An antibacterial biodegradable food packaging film and a method for preparing the same
By introducing tea polyphenols and hydrotalcite grafts into biodegradable food packaging films, the problems of insufficient antibacterial properties and mechanical properties were solved, and a biodegradable food packaging film with high antibacterial efficiency and high strength was prepared.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- GUANGDONG NANXIN PRINT & PACKAGING CO LTD
- Filing Date
- 2026-04-11
- Publication Date
- 2026-06-12
AI Technical Summary
Existing biodegradable food packaging films have insufficient antibacterial properties and mechanical defects, making it difficult to meet the long-term storage and transportation needs of food packaging.
Using polylactic acid and polybutylene succinate as the base materials, antibacterial and mechanical properties are enhanced by tea polyphenol grafts and hydrotalcite grafts. The tea polyphenol grafts are protected by hydroxyl-terminated polycaprolactone, and the hydrotalcite grafts are stabilized by a chitosan coating layer to prevent aggregation, thus preparing an antibacterial biodegradable food packaging film.
The prepared film has efficient antibacterial properties and excellent mechanical properties, which can effectively inhibit bacterial adhesion and biofilm formation, while maintaining good biodegradability.
Smart Images
Figure CN122188357A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of biomass conversion materials technology, specifically to an antibacterial biodegradable food packaging film and its preparation method. Background Technology
[0002] Food packaging is a core link in the food industry chain, ensuring food safety, extending shelf life, and preventing external pollution. It is also a significant contributor to environmental impact. Currently, mainstream food packaging films on the market are primarily made of petrochemical synthetic plastics such as polyethylene, polypropylene, and polystyrene. While these materials offer advantages such as low cost, good processability, and moderate mechanical strength, their core drawbacks are difficult to avoid: they are difficult to biodegrade naturally, damaging soil and aquatic ecosystems.
[0003] To address the environmental challenges of traditional plastic packaging, biodegradable packaging films have gradually become a hot topic in research and application. Commonly used substrates include natural or synthetic biodegradable polymers such as polylactic acid, chitosan, starch, and sodium alginate. These materials can be completely decomposed by microorganisms into harmless substances such as carbon dioxide and water in composting or natural environments, thus solving the problem of plastic pollution at its source. However, existing conventional biodegradable food packaging films generally suffer from two major technological shortcomings, which severely restrict their large-scale application in the food packaging field.
[0004] Most single biodegradable substrates themselves do not possess antibacterial activity. Only a few natural polymers have weak antibacterial effects, but these have narrow antibacterial spectra and low antibacterial efficiency, making it difficult to achieve broad-spectrum inhibition of common food bacteria and fungi. In existing technologies, some researchers have endowed degradable films with antibacterial function by directly adding tea polyphenol grafts, but this has drawbacks. Tea polyphenol grafts are prone to aggregation and precipitation, resulting in uneven antibacterial effects and poor stability, making them unsuitable for the antibacterial requirements of long-term food storage and transportation.
[0005] Biodegradable substrates generally have mechanical property defects. After film formation, single substrates often exhibit low tensile strength, high brittleness, poor flexibility, and weak tear resistance, making it difficult to meet the mechanical requirements during packaging, transportation, and use.
[0006] Therefore, it is of great significance to develop a biodegradable food packaging film with antibacterial and mechanical reinforcement as its core features. Summary of the Invention
[0007] The purpose of this invention is to provide an antibacterial biodegradable food packaging film and its preparation method.
[0008] The objective of this invention can be achieved through the following technical solutions: An antibacterial biodegradable food packaging film comprises the following components by weight fraction: 20-35 parts polylactic acid, 10-20 parts polybutylene succinate, 2-3 parts tea polyphenol graft, 1-2 parts hydrotalcite graft, and 0.5-1 part calcium stearate lubricant.
[0009] Furthermore, the preparation method of the tea polyphenol graft includes the following steps: Step S1: Add 5-6g of tea polyphenols to 80-90ml of acetone, stir well, add chloroacetyl chloride while controlling the temperature, and after the addition is complete, raise the temperature to 20-30℃ and stir the reaction for 4-6 hours. After the reaction is completed, dry to obtain the tea polyphenol intermediate. Step S2: Add 4-5g of terminal hydroxyl polycaprolactone to 90-100ml of dimethyl sulfoxide, stir well, then add 3-4g of tea polyphenol intermediate and 0.1-0.2g of triethylamine, heat to 60-70℃, stir and react for 6-8h, after the reaction is completed, dry to obtain tea polyphenol graft.
[0010] Furthermore, in step S1, the temperature control temperature is 0-5℃.
[0011] Furthermore, the molecular weight of the terminal hydroxyl polycaprolactone is 2000-3000.
[0012] Through the above technical solution, the hydroxyl groups on tea polyphenols react with the acyl chloride on chloroacetyl chloride to obtain tea polyphenol intermediates; under the action of a catalyst, the chlorine on the tea polyphenol intermediates reacts with the hydroxyl groups on the terminal hydroxyl polycaprolactone to obtain tea polyphenol grafts.
[0013] Furthermore, the preparation method of the hydrotalcite graft includes the following steps: Step SS1: Add 5-6g of hydrotalcite to 100-110ml of toluene, sonicate for 10-20min, add 1-2g of hexamethylene diisocyanate and 0.1-0.2g of dibutyltin dilaurate, heat to 90-100℃, stir and react for 8-10h, after the reaction is complete, dry to obtain the hydrotalcite intermediate; Step SS2: Add 4-5g of hydrotalcite intermediate to 90-100ml of N,N-dimethylformamide, sonicate for 10-20min, add 2.5-3.5g of chitosan and 0.1-0.2g of dibutyltin dilaurate, heat and stir for 4-6h, after the reaction is complete, dry to obtain hydrotalcite graft.
[0014] Furthermore, in step SS1, the particle size of the hydrotalcite is 1-3 nm.
[0015] Furthermore, in step SS2, the heating temperature is 50-60℃.
[0016] Through the above technical solution, the hydroxyl groups on the surface of hydrotalcite react with the isocyanate on hexamethylene diisocyanate to obtain a hydrotalcite intermediate; the isocyanate groups on the hydrotalcite intermediate then react with the amino groups on chitosan to obtain a hydrotalcite graft.
[0017] A method for preparing an antibacterial biodegradable food packaging film includes the following steps: Step A: Polylactic acid, polybutylene succinate, tea polyphenol graft, hydrotalcite graft, and calcium stearate lubricant are placed in a mixing tank and thoroughly mixed. After melt extrusion, stranding, water cooling and shaping, and pelleting, antibacterial masterbatch is obtained.
[0018] Step B: The antibacterial masterbatch is subjected to unidirectional casting extrusion stretching, cooling, traction, edge trimming, irradiation, and winding to obtain an antibacterial biodegradable food packaging film.
[0019] The beneficial effects of this invention are: (1) The antibacterial biodegradable film prepared by the present invention is made of polylactic acid and polybutylene succinate as base materials and tea polyphenol grafts and hydrotalcite grafts as auxiliary materials, so that the antibacterial biodegradable food packaging film prepared by the present invention has antibacterial properties and high mechanical strength.
[0020] (2) In the antibacterial biodegradable film prepared by the present invention, the tea polyphenol graft is obtained by grafting hydroxyl polycaprolactone onto the tea polyphenol. The tea polyphenol is protected by a polymer carrier, which solves the problem that tea polyphenol is easy to oxidize and migrate when used directly. This allows it to retain its antibacterial activity during the thermal processing of the film, effectively inhibiting bacterial adhesion and biofilm formation. Ultimately, the grafted product exhibits a more efficient and longer-lasting antibacterial effect in the biodegradable food packaging film.
[0021] (3) In the antibacterial biodegradable film prepared by the present invention, the hydrotalcite graft is prepared by grafting chitosan onto hydrotalcite. Chitosan molecules form a continuous and uniform polymer coating layer on the surface of the hydrotalcite layered particles. This coating layer can effectively block the direct contact between hydrotalcite particles, weaken the originally strong hydrogen bonding force and electrostatic attraction between particles, inhibit the spontaneous aggregation and interlayer stacking of nanoparticles from the source, avoid the formation of large-size agglomerates, and finally prepare a biodegradable film with stable mechanical properties.
[0022] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description
[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0024] Figure 1 This is a flowchart illustrating the preparation process of an antibacterial biodegradable food packaging film according to the present invention. Detailed Implementation
[0025] 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. Embodiment 1 A method for preparing an antibacterial biodegradable food packaging film includes the following steps: Step A: According to the weight fraction, 20 parts of polylactic acid, 10 parts of polybutylene succinate, 2 parts of tea polyphenol graft, 1 part of hydrotalcite graft, and 0.5 parts of calcium stearate are placed in a mixing tank and thoroughly mixed. After melt extrusion, stretching, water cooling and shaping, and pelleting, antibacterial masterbatch is obtained.
[0026] Step B: The antibacterial masterbatch is subjected to unidirectional casting extrusion stretching, cooling, traction, edge trimming, irradiation, and winding to obtain an antibacterial biodegradable food packaging film.
[0027] The preparation method of the tea polyphenol graft includes the following steps: Step S1: Weigh 5g of tea polyphenols and add them to 80ml of acetone. Stir well and add 1.5g of chloroacetyl chloride at 0℃. After the addition is complete, raise the temperature to 20℃ and stir the reaction for 4 hours. After the reaction is complete, dry the product to obtain the tea polyphenol intermediate. Step S2: Weigh 4g of terminal hydroxyl polycaprolactone and add it to 100ml of dimethyl sulfoxide. Stir well, then add 4g of tea polyphenol intermediate and 0.2g of triethylamine. Heat to 70℃ and stir for 8 hours. After the reaction is complete, dry to obtain tea polyphenol graft.
[0028] The preparation method of the hydrotalcite graft includes the following steps: Step SS1: Weigh 5g of hydrotalcite and add it to 100ml of toluene. Disperse it by sonication for 10min. Add 1g of hexamethylene diisocyanate and 0.1g of dibutyltin dilaurate. Heat to 100℃ and stir for 10h. After the reaction is complete, dry to obtain the hydrotalcite intermediate. Step SS2: Weigh 5g of hydrotalcite intermediate and add it to 100ml of N,N-dimethylformamide. Disperse the mixture by sonication for 20min. Add 3.5g of chitosan and 0.2g of dibutyltin dilaurate. Heat the mixture to 60℃ and stir for 6h. After the reaction is complete, dry the mixture to obtain the hydrotalcite graft. Example
[0029] A method for preparing an antibacterial biodegradable food packaging film includes the following steps: Step A: According to the weight fraction, 21 parts of polylactic acid, 11 parts of polybutylene succinate, 2.8 parts of tea polyphenol graft, 1.9 parts of hydrotalcite graft, and 0.6 parts of calcium stearate are placed in a mixing tank and thoroughly mixed. After melt extrusion, stretching, water cooling and shaping, pelleting is performed to obtain antibacterial masterbatch.
[0030] Step B: The antibacterial masterbatch is subjected to unidirectional casting extrusion stretching, cooling, traction, edge trimming, irradiation, and winding to obtain an antibacterial biodegradable food packaging film.
[0031] The preparation methods for the tea polyphenol grafts and hydrotalcite grafts are the same as in Example 1. Example
[0032] A method for preparing an antibacterial biodegradable food packaging film includes the following steps: Step A: According to the weight fraction, 35 parts of polylactic acid, 20 parts of polybutylene succinate, 3 parts of tea polyphenol graft, 2 parts of hydrotalcite graft, and 1 part of calcium stearate are placed in a mixing tank and thoroughly mixed. After melt extrusion, stretching, water cooling and shaping, and pelleting, antibacterial masterbatch is obtained.
[0033] Step B: The antibacterial masterbatch is subjected to unidirectional casting extrusion stretching, cooling, traction, edge trimming, irradiation, and winding to obtain an antibacterial biodegradable food packaging film.
[0034] The preparation methods for the tea polyphenol grafts and hydrotalcite grafts are the same as in Example 1.
[0035] Comparative Example 1 A method for preparing an antibacterial biodegradable food packaging film includes the following steps: Step A: According to the weight fraction, 21 parts of polylactic acid, 11 parts of polybutylene succinate, 1.9 parts of hydrotalcite graft and 0.6 parts of calcium stearate are placed in a mixing tank and thoroughly mixed. After melt extrusion, stretching, water cooling and shaping, pelleting is performed to obtain antibacterial masterbatch.
[0036] Step B: The antibacterial masterbatch is subjected to unidirectional casting extrusion stretching, cooling, traction, edge trimming, irradiation, and winding to obtain an antibacterial biodegradable food packaging film.
[0037] The preparation method of the hydrotalcite graft is the same as that in Example 1.
[0038] Comparative Example 2 A method for preparing an antibacterial biodegradable food packaging film includes the following steps: Step A: According to the weight fraction, 21 parts of polylactic acid, 11 parts of polybutylene succinate, 2.8 parts of tea polyphenol grafts and 0.6 parts of calcium stearate are placed in a mixing tank and thoroughly mixed. After melt extrusion, stretching, water cooling and shaping, and pelleting, antibacterial masterbatch is obtained.
[0039] Step B: The antibacterial masterbatch is subjected to unidirectional casting extrusion stretching, cooling, traction, edge trimming, irradiation, and winding to obtain an antibacterial biodegradable food packaging film.
[0040] The preparation method of the tea polyphenol graft is the same as that in Example 1.
[0041] Comparative Example 3 A method for preparing an antibacterial biodegradable food packaging film includes the following steps: Step A: According to the weight fraction, 21 parts of polylactic acid, 11 parts of polybutylene succinate, 2.8 parts of tea polyphenols, 1.9 parts of hydrotalcite graft and 0.6 parts of calcium stearate are placed in a mixing tank and thoroughly mixed. After melt extrusion, stretching, water cooling and shaping, pelleting is performed to obtain antibacterial masterbatch.
[0042] Step B: The antibacterial masterbatch is subjected to unidirectional casting extrusion stretching, cooling, traction, edge trimming, irradiation, and winding to obtain an antibacterial biodegradable food packaging film.
[0043] The preparation method of the hydrotalcite graft is the same as that in Example 1.
[0044] Comparative Example 4 A method for preparing an antibacterial biodegradable food packaging film includes the following steps: Step A: According to the weight fraction, 21 parts of polylactic acid, 11 parts of polybutylene succinate, 2.8 parts of tea polyphenol graft, 1.9 parts of hydrotalcite, and 0.6 parts of calcium stearate are placed in a mixing tank and thoroughly mixed. After melt extrusion, stretching, water cooling and shaping, pelleting is performed to obtain antibacterial masterbatch.
[0045] Step B: The antibacterial masterbatch is subjected to unidirectional casting extrusion stretching, cooling, traction, edge trimming, irradiation, and winding to obtain an antibacterial biodegradable food packaging film.
[0046] The preparation method of the tea polyphenol graft is the same as that in Example 1.
[0047] Test case The antibacterial biodegradable food packaging films prepared in the embodiments and comparative examples of the present invention were used to prepare test samples. Staphylococcus aureus and Escherichia coli were used as bacterial strains, and the antibacterial properties of the samples were tested according to standard QB / T 2591-2003; the tensile strength of the samples was tested according to standard GB / T 4456-2008.
[0048] Based on the experimental data above, the films prepared in Examples 1-3 all exhibited an antibacterial rate ≥98.7% and a tensile strength ≥26.3 MPa. The addition of tea polyphenol grafts and hydrotalcite grafts during the preparation process prevented tea polyphenols from migrating and oxidizing, thus enhancing their antibacterial properties. The hydrotalcite graft, consisting of chitosan grafted onto hydrotalcite, prevented hydrotalcite from agglomerating. Ultimately, the antibacterial biodegradable food packaging film prepared by this invention possesses excellent antibacterial properties and high strength.
[0049] Example 2 was compared with Comparative Examples 1 and 3. The antibacterial film prepared with added tea polyphenol grafts showed a higher antibacterial rate than the antibacterial films prepared without added tea polyphenol grafts and those prepared with added tea polyphenols. Therefore, the film prepared with added tea polyphenol grafts exhibits excellent antibacterial properties.
[0050] Example 2 was compared with Comparative Examples 2 and 4. The antibacterial film prepared with the addition of hydrotalcite grafts had a higher tensile strength than the antibacterial films prepared without hydrotalcite grafts and those prepared with hydrotalcite grafts. Therefore, the film prepared with the addition of hydrotalcite grafts exhibits high strength properties.
[0051] The above description is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the concept of the invention or exceed the scope defined in the claims, they should all fall within the protection scope of the present invention.
Claims
1. An antibacterial biodegradable food packaging film, characterized in that, The composition by weight fraction includes the following components: 20-35 parts polylactic acid, 10-20 parts polybutylene succinate, 2-3 parts tea polyphenol graft, 1-2 parts hydrotalcite graft, and 0.5-1 part calcium stearate lubricant.
2. The antibacterial biodegradable food packaging film according to claim 1, characterized in that, The preparation method of the tea polyphenol graft includes the following steps: Step S1: Add tea polyphenols to acetone, stir well, add chloroacetyl chloride while controlling the temperature, and after the addition is complete, raise the temperature to 20-30℃, stir the reaction for 4-6 hours, and after the reaction is completed, dry to obtain tea polyphenol intermediate; Step S2: Add hydroxyl-terminated polycaprolactone to dimethyl sulfoxide, stir until homogeneous, then add tea polyphenol intermediate and triethylamine, heat to 60-70℃, stir for 6-8 hours, after the reaction is complete, dry to obtain tea polyphenol graft.
3. The antibacterial biodegradable food packaging film according to claim 2, characterized in that, In step S1, the temperature control temperature is 0-5℃.
4. The antibacterial biodegradable food packaging film according to claim 2, characterized in that, In step S2, the molecular weight of the terminal hydroxyl polycaprolactone is 2000-3000.
5. The antibacterial biodegradable food packaging film according to claim 1, characterized in that, The preparation method of the hydrotalcite graft includes the following steps: Step SS1: Add hydrotalcite to toluene, sonicate for 10-20 min, add hexamethylene diisocyanate and dibutyltin dilaurate, heat to 90-100℃, stir and react for 8-10 h, after the reaction is completed, dry to obtain hydrotalcite intermediate; Step SS2: Add the hydrotalcite intermediate to N,N-dimethylformamide, ultrasonically disperse for 10-20 min, add chitosan and dibutyltin dilaurate, heat, stir and react for 4-6 h, after the reaction is complete, dry to obtain the hydrotalcite graft.
6. The antibacterial biodegradable food packaging film according to claim 5, characterized in that, In step SS1, the particle size of the hydrotalcite is 1-3 nm.
7. The antibacterial biodegradable food packaging film according to claim 5, characterized in that, In step SS2, the heating temperature is 50-60℃.
8. A method for preparing an antibacterial biodegradable food packaging film as described in claim 1, characterized in that, Includes the following steps: Step A: Polylactic acid, polybutylene succinate, tea polyphenol graft, hydrotalcite graft, and calcium stearate lubricant are placed in a mixing tank and thoroughly mixed. After melt extrusion, stranding, water cooling and shaping, and pelleting, antibacterial masterbatch is obtained. Step B: The antibacterial masterbatch is subjected to unidirectional casting extrusion stretching, cooling, traction, edge trimming, irradiation, and winding to obtain an antibacterial biodegradable food packaging film.