A kind of water-based polyvinyl chloride emulsion, preparation method of functional film and application thereof

Abstract

The invention belongs to the technical field of polymer composite materials, and discloses a method for preparing an aqueous polyvinyl chloride emulsion and a functional film and applications thereof, wherein the preparation steps are as follows: firstly, a hydrophilic modifier and polyvinyl chloride are reacted to obtain hydrophilic modified polyvinyl chloride; then a quaternary ammonium salt is used to modify a lignin derivative to obtain a lignin quaternary ammonium salt; finally, the lignin quaternary ammonium salt and the hydrophilic modified polyvinyl chloride are uniformly dispersed in a mesh gel structure of sodium carboxymethyl cellulose to obtain an aqueous polyvinyl chloride emulsion, and further film-formed to obtain a polyvinyl chloride functional film. The polyvinyl chloride functional film provided by the invention has good hydrophilic properties, anti-ultraviolet and antibacterial properties, and the preparation process is convenient to operate, conforms to the concept of green environmental protection, and can be applied to the fields of film materials such as gloves and functionalized packaging.

Description

Technical Field

[0001] The invention relates to the technical field of polymer composite materials, and in particular to a water-based polyvinyl chloride emulsion, a preparation method of a functional film and applications thereof. Background Art

[0002] Polyvinyl chloride is the third most commonly used plastic in the world, second only to polypropylene and polyethylene. Its synthesis method is simple and fast, which makes it inexpensive and one of the most widely used synthetic materials in various fields. It has been mass-produced and used worldwide since the early 20th century. It is supplied to various industries and commerce in the form of various formulations, usually as white powder or colorless granules. The structure of polyvinyl chloride gives it a series of remarkable physical and chemical properties, such as strong mechanical strength and excellent chemical stability, resistance to moisture, weathering, acid, alkali, fat and oil, and many organic solvents, and good corrosion resistance. It is easy to color and can be manufactured in various forms including sheets, films, fibers and foams. Nowadays, the application of functional polymers is becoming more and more extensive. Polyvinyl chloride-based functional polymers are widely used in building materials, wires and cables, leather seats, industrial parts, biomedicine and packaging products.

[0003] In addition, with the continuous improvement of living standards, people pay more and more attention to health issues, and polyvinyl chloride film products are also required to have antibacterial and anti-ultraviolet effects. Therefore, in order to improve the antibacterial properties of plastic films, it is often necessary for the polymer itself to have certain antibacterial properties (such as the generation of oxidative free radicals) or to add some oxidative antibacterial materials (such as nanosilver, nanozinc oxide) to the polymer. In patent CN117586590A "Self-polarized polyvinylidene fluoride composites and their use in the preparation of antibacterial products", the polarized polyvinyl fluoride composite material produces a large number of reducing free radicals and oxidizing free radicals to achieve the antibacterial and bactericidal effect. However, free radicals can damage human proteins and genes, destroy cell membranes, and participate in the occurrence and development of various diseases such as inflammation, tumors and blood diseases. Patent CN117603544A "A kind of antibacterial and anti-mildew modified plastic and its preparation method" uses nano zinc oxide as an antibacterial modifier and adds it to modified polyvinyl chloride to improve the antibacterial property of polyvinyl chloride. However, recent studies have shown that although nano zinc oxide can kill bacteria, it can also damage animal mitochondria and DNA. Although the coating in patent CN117442787A "A kind of medical catheter surface lubricating antibacterial drug-loaded coating and its preparation method and application" has good biocompatibility, it is only applied to the polymer surface and has the problem of poor antibacterial performance sustainability and stability. Therefore, how to ensure the antibacterial performance of polyvinyl chloride film and be friendly to organisms while having good antibacterial stability and sustainability is of great significance to the application of the antibacterial performance of polyvinyl chloride film. Summary of the invention

[0004] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a water-based polyvinyl chloride emulsion, a method for preparing a functional film and its application. The polyvinyl chloride functional film has enhanced hydrophilicity, anti-ultraviolet properties and antibacterial properties, and can be applied to packaging products, biomedicine and other fields.

[0005] In order to achieve the purpose, the present invention adopts the following technical scheme:

[0006] The invention firstly provides an aqueous polyvinyl chloride emulsion and a functional film, which are obtained by blending hydrophilic modified polyvinyl chloride and lignin quaternary ammonium salt, wherein the hydrophilic modified polyvinyl chloride is obtained by modifying the polyvinyl chloride with hydrophilic modifiers such as triethanolamine, bifunctional thiophenol, acid anhydride, quaternary ammonium salt and the like.

[0007] The present invention further provides a method for preparing the aqueous polyvinyl chloride emulsion and the functional film: firstly, a hydrophilic modifier and polyvinyl chloride are reacted to obtain hydrophilic modified polyvinyl chloride; then a lignin derivative is modified with a quaternary ammonium salt to obtain a lignin quaternary ammonium salt; finally, the lignin quaternary ammonium salt and the hydrophilic modified polyvinyl chloride are uniformly dispersed in a mesh gel structure of sodium carboxymethyl cellulose to obtain an aqueous polyvinyl chloride emulsion, and further film-formed to obtain a polyvinyl chloride functional film. The polyvinyl chloride functional film provided by the present invention has hydrophilic groups such as hydroxyl, amino, and carboxyl groups, which can provide enhanced hydrophilicity, a benzene ring structure can provide anti-ultraviolet performance, and a quaternary ammonium salt structure can effectively kill bacteria.

[0008] Furthermore, the method for preparing the aqueous polyvinyl chloride emulsion and the functional film of the present invention specifically comprises the following steps:

[0009] (1) Preparation of hydrophilic modified polyvinyl chloride: dissolve polyvinyl chloride paste resin in a solvent, then add a catalyst and a hydrophilic modifier in sequence, and react at 50-65°C for 12-20 hours; wash the reaction mixture in methanol and water below 0-10°C in sequence, dry, and crush to obtain a primary hydrophilic modified polyvinyl chloride;

[0010] The primary hydrophilic modified polyvinyl chloride is dissolved in a solvent, and a hydrophilic modifier is added to react at 50-65° C. for 12-20 h; the reaction mixture is washed in methanol at 0-10° C., dried, and crushed to obtain a secondary hydrophilic modified polyvinyl chloride.

[0011] (2) Preparation of lignin quaternary ammonium salt: disperse the lignin derivative in water, add a sodium hydroxide aqueous solution with a concentration of 0.1-0.7 mol / L, heat at 80-100°C and add 2,3-epoxypropyltrimethylammonium chloride dropwise to react for 3-5 hours; dialyze the resulting mixed solution and freeze-dry to obtain a lignin quaternary ammonium salt; dissolve the obtained lignin quaternary ammonium salt in deionized water to prepare a lignin quaternary ammonium salt aqueous solution.

[0012] (3) Preparation of water-based polyvinyl chloride emulsion: The primary hydrophilic modified polyvinyl chloride or secondary hydrophilic modified polyvinyl chloride is mixed with polyvinyl chloride paste resin, water, emulsifier, calcium zinc stabilizer and defoamer at 20-100° C. and stirred for 0-1.5 h; then, a dispersing stabilizer, sodium carboxymethyl cellulose, is added and stirred evenly; then, the lignin quaternary ammonium salt aqueous solution obtained in step (2) is added and stirred for 0-1.5 h; finally, a plasticizer is added and stirred for 0-1.5 h to obtain a water-based polyvinyl chloride emulsion.

[0013] (4) Preparation of polyvinyl chloride functional film: The aqueous polyvinyl chloride emulsion obtained in step (3) is subjected to vacuum degassing, poured into a mold to form a film, dried, and demolded to obtain a polyvinyl chloride functional film.

[0014] Preferably, in step (1), the hydrophilic modifier is at least one of triethanolamine, p-hydroxythiophenol, p-aminothiophenol, thiosalicylic acid, maleic anhydride, chloroacetylated N,N-dimethyldodecyl ammonium chloride (preparation method reference: QMWang, S. Liu, WJ Chen, YB Ni, SH Zeng, PP Chen, Y. Xu, WY Nie, YFZhou. Strong, bacteriostatic and transparent polylactic acid-based composites by incorporating quaternary ammonium cellulose nanocrystals [J]. International Journal of Biological Macromolecules, 2024, 274: 132645.), 2,3-epoxypropyltrimethylammonium chloride, N,N-dimethylbenzylamine and trimethylamine aqueous solution. Furthermore, the mass concentration of the trimethylamine aqueous solution is 33%.

[0015] Preferably, in step (1), the solvent is at least one of cyclohexanone, N,N-dimethylformamide, chloroform, tetrahydrofuran and water.

[0016] Preferably, in step (1), the catalyst is at least one of potassium carbonate, cesium carbonate, sodium bicarbonate and diisopropylamine.

[0017] Preferably, in step (1), when preparing the primary hydrophilic modified polyvinyl chloride, the mass ratio of the polyvinyl chloride paste resin, the catalyst and the hydrophilic modifier is 1:0~4:0.5~3; when preparing the secondary hydrophilic modified polyvinyl chloride, the mass ratio of the primary hydrophilic modified polyvinyl chloride and the hydrophilic modifier is 1:0.5~3.

[0018] Preferably, in step (2), the lignin derivative is at least one of alkali lignin, sodium lignin sulfonate, calcium lignin sulfonate and sulfonated lignin. The mass ratio of the lignin derivative to the quaternary ammonium salt (2,3-epoxypropyltrimethylammonium chloride) is 1:0.5-1.

[0019] Preferably, in step (2), the molecular weight cut-off of the dialysis bag for dialysis is 1-14 kDa.

[0020] Preferably, in step (3), the plasticizer is at least one of diisononyl phthalate, epoxy soybean oil and tricresyl phosphate. The emulsifier is at least one of sorbitan oleate (Span-80) and polysorbate (Tween-80).

[0021] Preferably, in step (3), the mass ratio of the primary hydrophilic modified polyvinyl chloride or secondary hydrophilic modified polyvinyl chloride, polyvinyl chloride paste resin, water, emulsifier, calcium zinc stabilizer, sodium carboxymethyl cellulose, lignin quaternary ammonium salt aqueous solution, defoamer and plasticizer is 50:40~60:100~300:6~10:1~2:0.5~5:20~80:0.01~0.1:80~100, wherein the mass concentration of the lignin quaternary ammonium salt aqueous solution is 50%.

[0022] The polyvinyl chloride functional film prepared by the invention has enhanced hydrophilicity, anti-ultraviolet property and antibacterial property, and can be used for preparing functionalized packaging film or gloves.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] 1. The present invention firstly reacts a hydrophilic modifier with polyvinyl chloride to obtain hydrophilic modified polyvinyl chloride, wherein the hydrophilic groups such as hydroxyl, amino, carboxyl, etc. on the modified graft can provide enhanced hydrophilicity, and can be dispersed in water through the synergistic effect of a compound emulsifier and a dispersion stabilizer to prepare an aqueous emulsion, thereby reducing the use of solvents and achieving a green environmental protection concept.

[0025] 2. In the polyvinyl chloride functional membrane of the present invention, the quaternary ammonium salt of lignin obtained by using a quaternary ammonium salt-modified lignin derivative is used. The quaternary ammonium salt of lignin and the hydrophilic modified polyvinyl chloride are uniformly dispersed in the network gel structure of sodium carboxymethyl cellulose, and there are electrostatic adsorption, hydrogen bonding and complexation, which improves the dispersion stability and uniformity of the quaternary ammonium salt of lignin and the hydrophilic modified polyvinyl chloride.

[0026] 3. The quaternary ammonium salt of lignin added to the polyvinyl chloride functional film of the present invention contains a benzene ring structure, which has an absorption effect on the wavelength of the ultraviolet region, and thus can provide anti-ultraviolet performance. At the same time, the quaternary ammonium salt structure can adsorb negatively charged bacteria and destroy the cell wall of the bacteria, thereby being able to play an effective bactericidal role.

[0027] 4. The polyvinyl chloride functional film of the present invention has a convenient production process and utilizes the derivatives of cellulose and lignin that are abundant in nature, as well as environmentally friendly and degradable emulsifiers during the production process. The preparation cost is low, conforms to the green environmental protection concept, and is suitable for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The water contact angles of the hydrophilic modified polyvinyl chloride obtained in Examples 1-8 of the present invention and Comparative Example 2.

[0029] Figure 2 The curves of light transmittance of the polyvinyl chloride functional films obtained in Examples 9 to 12 of the present invention and Comparative Example 1 as a function of wavelength are shown.

[0030] Figure 3 The water contact angle test diagram of the polyvinyl chloride functional film obtained in Examples 9-12 of the present invention and Comparative Example 1 is shown in FIG. Figure 3 (a) corresponds to the water contact angle (0 to 50 s), Figure 3 (b) corresponds to the camera images of the water droplet at the initial stage and when it is completely absorbed on the polyvinyl chloride functional film.

[0031] Figure 4 The antibacterial effect diagram of the polyvinyl chloride functional membrane obtained in Examples 9-12 of the present invention and Comparative Example 1 after culturing Staphylococcus aureus for 0 min, 60 min, 120 min and 180 min.

[0032] Figure 5 The antibacterial rate change curves of the polyvinyl chloride functional films obtained in Examples 9 to 12 of the present invention and Comparative Example 1 after culturing Staphylococcus aureus for 0 min, 60 min, 120 min and 180 min.

[0033] Figure 6 The scanning electron microscope images are of the surface and cross-sectional morphologies of the polyvinyl chloride functional films obtained in Examples 9-12 of the present invention and Comparative Example 1. Figure 6(a1) and (a2) in the figure correspond to the surface and cross section of Example 1, respectively. Figure 6 (b1) and (b2) correspond to the surface and cross section of Example 9, respectively. Figure 6 (c1) and (c2) correspond to the surface and cross section of Example 10, respectively. Figure 6 (d1) and (d2) correspond to the surface and cross section of Example 11, respectively. Figure 6 (e1) and (e2) correspond to the surface and cross section of Example 12, respectively. DETAILED DESCRIPTION

[0034] The following is a detailed description of an embodiment of the present invention. This embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation method and a specific operation process are given, but the protection scope of the present invention is not limited to the following embodiment.

[0035] Example 1

[0036] This embodiment provides a method for preparing hydrophilic modified polyvinyl chloride, comprising the following steps:

[0037] 5 g of polyvinyl chloride paste resin was dissolved in 400 mL of cyclohexanone solvent, and 20 g of potassium carbonate and 10 g of triethanolamine were added, and the mixture was reacted in an oil bath at 60°C for 12 h. After the reaction, the reaction mixture was washed three times with methanol and water at 5°C, dried in a vacuum drying oven at 50°C for 24 h, and crushed to obtain hydrophilic modified polyvinyl chloride.

[0038] Example 2

[0039] This embodiment provides a method for preparing hydrophilic modified polyvinyl chloride, comprising the following steps:

[0040] 5 g of polyvinyl chloride paste resin was dissolved in 400 mL of cyclohexanone solvent, and 20 g of potassium carbonate and 10 g of p-hydroxythiophenol were added, and the mixture was reacted in an oil bath at 60°C for 12 h. After the reaction, the reaction mixture was washed three times with methanol and water at 5°C, dried in a vacuum drying oven at 50°C for 24 h, and crushed to obtain hydrophilic modified polyvinyl chloride.

[0041] Example 3

[0042] This embodiment provides a method for preparing hydrophilic modified polyvinyl chloride, comprising the following steps:

[0043] 5 g of polyvinyl chloride paste resin was dissolved in 400 mL of cyclohexanone solvent, and 20 g of potassium carbonate and 10 g of p-aminothiophenol were added, and the mixture was reacted in an oil bath at 60°C for 12 h. After the reaction, the reaction mixture was washed three times with methanol and water at 5°C, dried in a vacuum drying oven at 50°C for 24 h, and crushed to obtain hydrophilic modified polyvinyl chloride.

[0044] Example 4

[0045] This embodiment provides a method for preparing hydrophilic modified polyvinyl chloride, comprising the following steps:

[0046] 5 g of polyvinyl chloride paste resin was dissolved in 400 mL of cyclohexanone solvent, and 20 g of potassium carbonate and 10 g of thiosalicylic acid were added, and the mixture was reacted in an oil bath at 60°C for 12 h. After the reaction, the reaction mixture was washed three times with methanol and water at 5°C, dried in a vacuum drying oven at 50°C for 24 h, and crushed to obtain hydrophilic modified polyvinyl chloride.

[0047] Example 5

[0048] This embodiment provides a method for preparing hydrophilic modified polyvinyl chloride, comprising the following steps:

[0049] 5 g of the product of Example 3 was dissolved in 250 mL of N,N-dimethylformamide solvent, and the solution was deaerated by bubbling high-purity argon gas, and then 5 g of maleic anhydride was added. Under argon atmosphere, the reaction mixture was stirred in a 50°C oil bath for 12 h. After the reaction was completed, the reaction mixture was washed three times with 5°C methanol, dried in a 50°C vacuum drying oven for 24 h, and crushed to obtain hydrophilic modified polyvinyl chloride.

[0050] Example 6

[0051] This embodiment provides a method for preparing hydrophilic modified polyvinyl chloride, comprising the following steps:

[0052] 5 g of the product of Example 3 was dissolved in 400 mL of cyclohexanone solvent, 5 g of chloroacetylated N,N-dimethyldodecylammonium chloride was added, and the reaction mixture was stirred in a 50°C oil bath for 12 h. After the reaction was completed, the reaction mixture was washed three times with 5°C methanol, dried in a 50°C vacuum drying oven for 24 h, and crushed to obtain hydrophilic modified polyvinyl chloride.

[0053] Example 7

[0054] This embodiment provides a method for preparing hydrophilic modified polyvinyl chloride, comprising the following steps:

[0055] 5 g of the product of Example 4 was dissolved in 350 mL of chloroform solvent, 10 g of 2,3-epoxypropyltrimethylammonium chloride was added, and the reaction mixture was stirred in a 65°C oil bath for 20 h. After the reaction was completed, the reaction mixture was washed three times with 5°C methanol, dried in a 50°C vacuum drying oven for 24 h, and crushed to obtain hydrophilic modified polyvinyl chloride.

[0056] Example 8

[0057] This embodiment provides a method for preparing hydrophilic modified polyvinyl chloride, comprising the following steps:

[0058] 5 g of the product of Example 4 was dispersed in 15 mL of water, 10 g of trimethylamine aqueous solution was added, and the reaction mixture was stirred in a 50°C oil bath for 12 h. After the reaction was completed, the reaction mixture was washed three times with 5°C methanol, dried in a 50°C vacuum drying oven for 24 h, and crushed to obtain hydrophilic modified polyvinyl chloride.

[0059] Example 9

[0060] This embodiment provides a method for preparing a multifunctional modified polyvinyl chloride composite film and its application, comprising the following steps:

[0061] 1. Disperse 5 g of sodium lignin sulfonate in 10 mL of water, add 40 mL of 0.1 mol / L sodium hydroxide aqueous solution, heat at 85 °C and drop 5 g of 2,3-epoxypropyltrimethylammonium chloride to react for 4 h; dialyze the resulting mixed solution (the molecular weight cutoff of the dialysis bag is 1000 Da) and freeze-dry to obtain lignin quaternary ammonium salt; dissolve the obtained lignin quaternary ammonium salt in deionized water to prepare a 50 wt% lignin quaternary ammonium salt aqueous solution.

[0062] 2. Add 50 parts of the hydrophilic modified polyvinyl chloride prepared in Example 7, 50 parts of polyvinyl chloride paste resin, 100 parts of water, 4 parts of emulsifier Span-80, 4 parts of emulsifier Tween-80, 1.5 parts of calcium zinc stabilizer and 0.05 parts of defoamer into a flask, and stir in a 50°C oil bath for 10 min; then add 1.5 parts of sodium carboxymethyl cellulose, continue stirring in a 50°C oil bath for 20 min, then add 20 parts of lignin quaternary ammonium salt aqueous solution, and continue stirring in a 50°C oil bath for 30 min; finally, add 92 parts of diisononyl phthalate, and continue stirring in a 50°C oil bath for 20 min to obtain an aqueous polyvinyl chloride emulsion.

[0063] 3. The obtained aqueous polyvinyl chloride emulsion is vacuum degassed, then poured into a mold and cast into a film, first dried in an oven at 80°C for 10 h, then baked in an oven at 200°C for 10 min, taken out and cooled to room temperature before demolding to obtain a polyvinyl chloride functional film.

[0064] Example 10

[0065] This embodiment prepares a polyvinyl chloride functional film according to the same method and steps as in Embodiment 9, except that the number of parts of the lignin quaternary ammonium salt aqueous solution in Step 2 is changed from 20 parts to 40 parts.

[0066] Embodiment 11

[0067] This embodiment prepares a polyvinyl chloride functional film according to the same method and steps as in Embodiment 9, except that the number of parts of the lignin quaternary ammonium salt aqueous solution in Step 3 is changed from 20 parts to 60 parts.

[0068] Example 12

[0069] This embodiment prepares a polyvinyl chloride functional film according to the same method and steps as in Embodiment 9, except that the number of parts of the lignin quaternary ammonium salt aqueous solution in Step 3 is changed from 20 parts to 80 parts.

[0070] Comparative Example 1

[0071] In this comparative example, a polyvinyl chloride functional film is prepared according to the same method and steps as in Example 9, except that the number of parts of the lignin quaternary ammonium salt aqueous solution in step 3 is changed from 20 parts to 0 parts.

[0072] Comparative Example 2

[0073] The pure polyvinyl chloride sample was washed in methanol and water in turn, and then dried in a vacuum drying oven at 50 °C for 24 h.

[0074] The samples obtained in each embodiment were subjected to the following performance tests:

[0075] 1. Contact angle test of hydrophilic modified polyvinyl chloride

[0076] like Figure 1 As shown, the contact angle of Comparative Example 2 is 87.3°, and after modification in different ways, the contact angles of the hydrophilic modified polyvinyl chloride surfaces are all reduced to below 75°, and the hydrophilicity is improved. Among them, the most significant improvement in hydrophilicity is in Example 7, with a water contact angle of 62.7°, which is reduced by 24.6°.

[0077] 2. Anti-ultraviolet performance test of polyvinyl chloride functional film

[0078] The polyvinyl chloride functional films obtained in Examples 9-12 and Comparative Example 1 were cut into 5 cm×1 cm samples, and placed in a fixture. The light transmittance of the films was tested using a UV-2600i ultraviolet-visible-near-infrared spectrophotometer.

[0079] like Figure 2 As shown in the figure, with the increase of lignin quaternary ammonium salt content, the transmittance of the composite film continued to decrease in the visible light region (400 ~ 600 nm) and in the near-ultraviolet region (298 ~ 400 nm), and the decline gradually decreased. The decrease in transmittance in the entire visible spectrum indicates that the multifunctional modified polyvinyl chloride composite film has enhanced anti-ultraviolet properties.

[0080] 3. Dynamic contact angle test of polyvinyl chloride functional film

[0081] like Figure 3 As shown, compared with Comparative Example 1, it is found that the addition of lignin quaternary ammonium salt can significantly improve the water absorption of the polyvinyl chloride functional film, and as the content of lignin quaternary ammonium salt increases, the time from the water droplet dripping on the film surface to being completely absorbed becomes shorter and shorter. Example 9 requires 50 s to completely absorb the water droplet, while Example 12 only requires 4 s, and the water absorption of the composite film gradually increases.

[0082] 4. Antibacterial performance test of polyvinyl chloride functional film

[0083] The antibacterial test of this experiment was carried out in a biological safety cabinet, and the plate colony counting method was used to calculate the antibacterial rate of the polyvinyl chloride functional membrane obtained in Examples 9-12 and Comparative Example 1 against Staphylococcus aureus (S. aureus). Before the experiment, solid culture medium and liquid culture medium were prepared: 3g of trypsin soy bean liquid medium (TSB) was weighed and dissolved in 100mL of deionized water to prepare liquid culture medium, which was placed in a high-temperature autoclave at 120℃ for 1h for sterilization; 3g of trypsin soy bean liquid medium (TSB) and 1.5g of agar powder were weighed and dissolved in 100mL of deionized water, and solid culture medium was prepared by the same treatment. The polyvinyl chloride functional membrane was cut into discs with a diameter of 5 mm.

[0084] After the culture solution was sterilized at high temperature and high pressure, it was concentrated to 20 μL, poured into a 10 mL container, and then 6 mL of sterile water was added to ensure that it was completely dissolved. Then 200 μL of bacterial solution was taken out from the test tube and placed in a centrifuge tube, and then 3.3 mL of sterile water was added. After stirring evenly, 30 μL was taken and coated on the solid culture medium; 3 empty culture dishes were taken out and polyvinyl chloride functional membrane discs of the same size were placed in each of them, 200 μL of bacterial solution was dripped on each disc, and placed in a 37°C oven for 0 min to 180 min (time interval of 60 min). The composite membrane discs of each embodiment were cultured in the same way. After the culture was completed, it was placed in an empty centrifuge tube, 8 mL of PBS buffer was added, and ultrasonic treatment was performed for 5 minutes, and then 30 μL was taken out and coated on the surface. All the coated solid culture media were marked with a marker and placed in a 37°C oven for 21 to 24 h and counted. The antibacterial efficiency calculation formula is as follows:

[0085]

[0086] Where: R represents the antibacterial rate (%); B represents the number of colonies in the blank control group (pieces); C represents the number of colonies on the solid culture medium after culturing for 21 to 24 hours (pieces).

[0087] like Figure 4 and Figure 5 As shown, compared with Comparative Example 1, Examples 9 to 12 all showed significant inhibitory activity, indicating that the addition of lignin quaternary ammonium salt can increase the antibacterial properties of the polyvinyl chloride functional film. After 180 min, the antibacterial rate of Example 9 reached 97.2%, and the antibacterial rate of Example 10 reached 99.84%. The antibacterial rate of Example 12 reached 97.4% after 60 min, and Staphylococcus aureus was completely killed after 120 min, confirming that the multifunctional modified polyvinyl chloride composite film provided by the present invention can provide antibacterial ability.

[0088] 5. SEM morphology of polyvinyl chloride functional membrane

[0089] like Figure 6 As shown, compared with Comparative Example 1 ( Figure 6 By comparing (a1) and (a2) in the figure, it is found that after adding the quaternary ammonium salt of lignin, the surface and cross section of the polyvinyl chloride functional film obtained in Example 9 ( Figure 6 Both (b1) and (b2) in the examples have microporous structures, which is caused by the decomposition of some organic light component gases by lignin during film formation. This also indicates that the addition of lignin quaternary ammonium salt will affect the mechanical properties of the polyvinyl chloride functional film. Figure 6 (c1) and (c2)), Example 11 ( Figure 6The micropores on the surface of the polyvinyl chloride functional membrane obtained by (d1) and (d2)) increase, the cross-sectional pores increase, and gradually deepen grooves and cracks appear. The cross-sectional pores are connected to form gullies. The grooves are due to the ion adsorption of lignin quaternary ammonium salt as an anionic surfactant with sodium carboxymethyl cellulose, which reduces the compatibility of lignin quaternary ammonium salt with polyvinyl chloride. The cracks are caused by the rigid structure of the benzene ring of lignin quaternary ammonium salt. Example 12 ( Figure 6 The surface defects of (e1) and (e2) are more serious, and the aggregation of lignin quaternary ammonium salt or carboxymethyl cellulose particles appears. The cross section also shows the aggregation of particles, and even huge holes appear, which can be predicted to seriously affect the practical application of the composite membrane. When the content of lignin quaternary ammonium salt is 40 parts or less, the morphology has little effect on the practical application.

[0090] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. All modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a water-based polyvinyl chloride functional film, characterized in that: The steps include: (1) Preparation of hydrophilic modified polyvinyl chloride: dissolve polyvinyl chloride paste resin in a solvent, then add a catalyst and a hydrophilic modifier in sequence, and react at 50-65°C for 12-20 h; wash the reaction mixture in methanol and water at 0-10°C in sequence, dry, and crush to obtain a primary hydrophilic modified polyvinyl chloride; The primary hydrophilic modified polyvinyl chloride is dissolved in a solvent, and a hydrophilic modifier is added, and the reaction is carried out at 50-65° C. for 12-20 h; the reaction mixture is washed in methanol at 0-10° C., dried, and crushed to obtain a secondary hydrophilic modified polyvinyl chloride; The catalyst is at least one of potassium carbonate, cesium carbonate, sodium bicarbonate and diisopropylamine; the hydrophilic modifier is at least one of triethanolamine, p-hydroxythiophenol, p-aminothiophenol, thiosalicylic acid, maleic anhydride, chloroacetylated N,N-dimethyldodecyl ammonium chloride, 2,3-epoxypropyltrimethylammonium chloride, N,N-dimethylbenzylamine and trimethylamine aqueous solution; (2) Preparation of lignin quaternary ammonium salt: disperse the lignin derivative in water, add a sodium hydroxide aqueous solution with a concentration of 0.1-0.7 mol / L, heat at 80-100°C and drop 2,3-epoxypropyltrimethylammonium chloride to react for 3-5 h; dialyze the resulting mixed solution and freeze-dry to obtain a lignin quaternary ammonium salt; dissolve the obtained lignin quaternary ammonium salt in deionized water to prepare a lignin quaternary ammonium salt aqueous solution; (3) Preparation of water-based polyvinyl chloride emulsion: the primary hydrophilic modified polyvinyl chloride or secondary hydrophilic modified polyvinyl chloride is mixed with polyvinyl chloride paste resin, water, emulsifier, calcium zinc stabilizer and defoamer at 20-100° C. and stirred for 0-1.5 h; then, a dispersion stabilizer, sodium carboxymethyl cellulose, is added and stirred evenly, and then the lignin quaternary ammonium salt aqueous solution obtained in step (2) is added and stirred for 0-1.5 h; finally, a plasticizer is added and stirred for 0-1.5 h to obtain a water-based polyvinyl chloride emulsion; (4) Preparation of polyvinyl chloride functional film: The aqueous polyvinyl chloride emulsion obtained in step (3) is subjected to vacuum degassing, poured into a mold to form a film, dried, and demolded to obtain a polyvinyl chloride functional film.

2. The preparation method according to claim 1, characterized in that: In step (1): the solvent is at least one of cyclohexanone, N,N-dimethylformamide, chloroform, tetrahydrofuran and water.

3. The preparation method according to claim 1, characterized in that: In step (1): when preparing the primary hydrophilic modified polyvinyl chloride, the mass ratio of the polyvinyl chloride paste resin, the catalyst and the hydrophilic modifier is 1:0~4:0.5~3; when preparing the secondary hydrophilic modified polyvinyl chloride, the mass ratio of the primary hydrophilic modified polyvinyl chloride and the hydrophilic modifier is 1:0.5~3.

4. The preparation method according to claim 1, characterized in that: In step (2), the dialysis treatment uses a dialysis bag with a molecular weight cutoff of 1 to 14 kDa.

5. The preparation method according to claim 1, characterized in that: In step (2), the lignin derivative is at least one of alkali lignin, sodium lignin sulfonate, calcium lignin sulfonate and sulfonated lignin.

6. The preparation method according to claim 1, characterized in that: In step (2), the mass ratio of the lignin derivative to 2,3-epoxypropyltrimethylammonium chloride is 1:0.5-1.

7. The preparation method according to claim 1, characterized in that: In step (3), the mass ratio of the primary hydrophilic modified polyvinyl chloride or secondary hydrophilic modified polyvinyl chloride, polyvinyl chloride paste resin, water, emulsifier, calcium zinc stabilizer, sodium carboxymethyl cellulose, lignin quaternary ammonium salt aqueous solution, defoamer and plasticizer is 50:40~60:100~300:6~10:1~2:0.5~5:20~80:0.01~0.1:80~100, wherein the mass concentration of the lignin quaternary ammonium salt aqueous solution is 50%.

8. The preparation method according to claim 1, characterized in that: In step (3), the plasticizer is at least one of diisononyl phthalate, epoxy soybean oil and tricresyl phosphate, and the emulsifier is at least one of sorbitan oleate and polysorbate.

9. A polyvinyl chloride functional film obtained by the preparation method according to any one of claims 1 to 8.

10. Use of the polyvinyl chloride functional film according to claim 9 in functionalized packaging films or gloves.

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