Antibacterial food packaging film and processing technology

Abstract

The application discloses an antibacterial food packaging film and a processing technology, and relates to the technical field of polyester plastics, which comprises a polyester degradable plastic base material; the application realizes the synergistic optimization of the antibacterial performance and the degradable performance of the packaging film by adopting a plurality of polyester materials to construct a base material blending system, collocating a compounded nano antibacterial material and adding auxiliary components, combining a solid-phase synthesis process and an antibacterial layer adhesion design on the surface of a plastic uptake forming die, forming a complementary effect through reasonable collocation of the plurality of polyester components, retaining the degradable characteristics of each component, and adapting to the forming requirements of the plastic uptake process; the compounded nano antibacterial material forms a synergistic effect based on different antibacterial mechanisms, can act on pathogenic bacteria in a targeted manner, the auxiliary components can enhance the internal bonding force of the antibacterial material and the adhesion force on the surface of the plastic uptake forming die, and the antibacterial nano material layer is closely attached to the base material in a die adhesion mode, thereby reducing the risk of falling and migration of the antibacterial components.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of polyester plastics, in particular to an antibacterial food packaging film and a processing technology. BACKGROUND

[0002] With the rapid development of the food industry, the circulation range of various products such as fresh fruits and vegetables, cooked meat products and instant foods is continuously expanding, and consumers' requirements for food shelf life and food safety are continuously increasing. At the same time, with the increasing global environmental awareness, the environmental pollution problem caused by traditional non-degradable plastic packaging is becoming increasingly prominent. Food packaging materials with antibacterial protection and degradability have become the core direction of industry transformation and market demand, and have irreplaceable practical significance in ensuring food quality and reducing environmental burden.

[0003] However, the antibacterial food packaging film and the processing technology in the prior art have some defects. In terms of the substrate, some products use a single polyester material, which is not designed by multiple components in cooperation, and it is difficult to balance the degradability and the adaptability of the plastic processing. In terms of the antibacterial system, the antibacterial material is mostly a single component or a disordered compound, and a targeted antibacterial system is not constructed, and no auxiliary component is added, which leads to uneven dispersion of the antibacterial component and weak bonding force with the carrier, and the antibacterial component is easy to fall off and migrate. In terms of the process, the synthesis process of the antibacterial material lacks effective control means, it is difficult to realize the precise structure-activity matching of the structural units, the antibacterial layer is attached in a simple way, the mold is not pretreated, and the forming process lacks cooperative design, and the detection process lacks standardized operation specification, so it is difficult to ensure the stability and consistency of the antibacterial effect. SUMMARY

[0004] The purpose of the present application is to make up for the deficiencies of the prior art, and to provide an antibacterial food packaging film and a processing technology. The present application uses multiple polyester materials to construct a substrate blending system, matches a compound nano-antibacterial material and adds an auxiliary component, combines a solid-phase synthesis process and an antibacterial layer attachment design on the surface of a plastic forming mold, realizes the cooperative optimization of the antibacterial performance and the degradability of the packaging film, and the multiple polyester components form a complementary effect through reasonable matching, which not only retains the degradability of each component, but also adapts to the forming requirements of the plastic processing. The compound nano-antibacterial material forms a synergistic effect based on different antibacterial mechanisms, can act on pathogenic bacteria in a targeted manner, the auxiliary component can enhance the internal bonding force of the antibacterial material and the adhesion force on the surface of the plastic forming mold, the antibacterial nano-material layer is closely attached to the substrate through the attachment of the mold, reduces the risk of falling off and migration of the antibacterial component, and forms a stable antibacterial protection system.

[0005] To solve the above technical problems, the application provides the following technical scheme: on the one hand, an antibacterial food packaging film, the packaging film comprising: a polyester degradable plastic substrate;

[0006] The polyester degradable plastic substrate is formed by a plastic absorption process, and the inner surface of the plastic absorption forming mold is attached with an antibacterial nanomaterial layer.

[0007] The antibacterial nanomaterial layer is composed of antibacterial functional nanomaterial synthesized by a solid phase method, and the structure unit scale of the antibacterial functional nanomaterial is 10nm-1μm.

[0008] The antibacterial food packaging film has an antibacterial width of 0.31mm or more for Staphylococcus aureus and an antibacterial width of 0.44mm or more for Escherichia coli.

[0009] Further, the polyester degradable plastic substrate is a blend of polylactic acid, polybutylene adipate, and polybutylene adipate terephthalate, and the mass ratio of each component in the blend is 40-60:20-35:15-30, and the melt index of the blend is 5-15g / 10min.

[0010] Further, the antibacterial functional nanomaterial is a compound of nano-zinc oxide, nano-silver, and nano-copper, and the mass ratio of each component in the compound is 40-70:5-15:20-45, and each component is mixed and reacted by a solid phase method to form a uniform antibacterial functional body.

[0011] Further, the compound of the antibacterial functional nanomaterial is added with a silane coupling agent, and the addition amount of the silane coupling agent is 3%-6% of the total mass of the antibacterial functional nanomaterial.

[0012] On the other hand, a processing process of an antibacterial food packaging film, the specific steps of which are as follows:

[0013] Material synthesis: take nano-zinc oxide, nano-silver, and nano-copper in a mass ratio of 40-70:5-15:20-45, and add a silane coupling agent accounting for 3-6% of the total mass of the three, synthesize antibacterial functional nanomaterial by a solid phase method, and adjust the synthesis parameters to obtain antibacterial functional nanomaterial with a structure unit scale of 10nm-1μm;

[0014] Mold pretreatment: clean and dry the plastic absorption forming mold to obtain a clean and impurity-free plastic absorption forming mold;

[0015] Antibacterial layer preparation: take the antibacterial functional nanomaterial, add deionized water, and add an emulsifier for emulsification treatment to obtain an emulsion, coat the emulsion on the inner surface of the plastic absorption forming mold, and form an antibacterial nanomaterial layer by baking treatment;

[0016] Blister forming: taking the polyester degradable plastic hard sheet with a melt index of 5-15 g / 10 min formed by blending polylactic acid, polybutylene adipate, and polybutylene adipate terephthalate at a mass ratio of 40-60:20-35:15-30, softening by heating, and then vacuum adsorbed on the surface of the blister forming mold with an antibacterial nano material layer, and then demolding after cooling to obtain an antibacterial food packaging film;

[0017] Performance detection: taking the antibacterial food packaging film, cutting a sample with a size of 20 mm x 20 mm, and detecting the antibacterial performance of Staphylococcus aureus and Escherichia coli.

[0018] Further, in the material synthesis, the step of synthesizing the antibacterial functional nano material by a solid phase method is: mixing nano zinc oxide, nano silver, nano copper, and silane coupling agent in proportion, mixing at a speed of 600-900 r / min and a temperature of 90-120℃ for 20-30 min, airflow crushing, and then screening to obtain an antibacterial functional nano material with a structure unit size of 10 nm-1 μm.

[0019] Further, in the mold pretreatment, the step of pretreating the blister forming mold is: cleaning the blister forming mold with an ultrasonic cleaning machine for 10-15 min at a cleaning power of 400-600 W, and then drying the blister forming mold in a drying oven at a temperature of 60-80℃ for 2-3 h.

[0020] Further, in the antibacterial layer preparation, the emulsifier is polyglycerol fatty acid ester or sucrose fatty acid ester, the addition amount of the emulsifier is 5-8% of the total mass of the antibacterial functional nano material and deionized water, the stirring speed of the emulsification treatment is 1200-1800 r / min, and the emulsification time is 20-30 min; air spraying is used for coating, the spraying pressure is 0.2-0.4 MPa, the baking temperature is 70-90℃, and the baking time is 40-60 min.

[0021] Further, in the blister forming, the heating temperature of the polyester degradable plastic hard sheet is 110-130℃, and the holding time is 2-4 min; the vacuum degree of vacuum adsorption is -0.08 MPa to -0.09 MPa, the adsorption time is 1-3 min, and the cooling process is natural cooling to room temperature.

[0022] Further, in the performance detection, the step of detecting the antibacterial performance is: sterilizing the sample, placing it in the center of a culture medium plate containing Staphylococcus aureus or Escherichia coli, tightly attaching the sample to the culture medium, incubating at 37℃ for 24-48 h, and then measuring the width of the antibacterial zone around the sample, wherein the antibacterial width for Staphylococcus aureus is ≥0.31 mm, and the antibacterial width for Escherichia coli is ≥0.44 mm.

[0023] Compared with the prior art, the antibacterial food packaging film and the processing technology have the following beneficial effects:

[0024] Firstly, the antibacterial food packaging film is prepared by adopting a plurality of polyester materials to construct a substrate blending system, matching a compounded nano antibacterial material, and adding auxiliary components, combining a solid phase synthesis process and a surface antibacterial layer attachment design of a blister forming mold, so as to realize the synergistic optimization of antibacterial performance and degradable performance of the packaging film. The plurality of polyester components form a complementary effect through reasonable matching, which not only retains the degradable characteristics of each component, but also adapts to the forming requirements of the blister process. The compounded nano antibacterial material forms a synergistic effect based on different antibacterial mechanisms, which can act on pathogenic bacteria in a targeted manner. The auxiliary components can enhance the internal bonding force of the antibacterial material and the adhesion force with the surface of the blister forming mold. The antibacterial nano material layer is closely attached to the substrate through the attachment of the mold, which reduces the risk of antibacterial component shedding and migration, and forms a stable antibacterial protection system.

[0025] Secondly, the antibacterial food packaging film is prepared by adopting a plurality of polyester materials to construct a substrate blending system, matching a compounded nano antibacterial material, and adding auxiliary components, combining a solid phase synthesis process and a surface antibacterial layer attachment design of a blister forming mold, so as to realize the synergistic optimization of antibacterial performance and degradable performance of the packaging film. The plurality of polyester components form a complementary effect through reasonable matching, which not only retains the degradable characteristics of each component, but also adapts to the forming requirements of the blister process. The compounded nano antibacterial material forms a synergistic effect based on different antibacterial mechanisms, which can act on pathogenic bacteria in a targeted manner. The auxiliary components can enhance the internal bonding force of the antibacterial material and the adhesion force with the surface of the blister forming mold. The antibacterial nano material layer is closely attached to the substrate through the attachment of the mold, which reduces the risk of antibacterial component shedding and migration, and forms a stable antibacterial protection system.

[0026] Other advantages, objects, and features of the present application will be apparent to those skilled in the art from the following specification, which is to be taken in conjunction with the accompanying drawings, wherein: BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creating any inventive labor.

[0028] Figure 1 The flow chart of the processing technology of the antibacterial food packaging film;

[0029] Figure 2 The flow chart of the processing technology of the antibacterial food packaging film;

[0030] Figure 3 A flow chart of the blister forming process in the processing technology of an antibacterial food packaging film. DETAILED DESCRIPTION

[0031] In order to further illustrate the technical means and effects adopted by the present application to achieve the predetermined inventive purposes, the specific embodiments, structures, features and effects according to the present application are described in detail below in combination with the drawings and preferred embodiments.

[0032] Example 1:

[0033] In the preparation scenario of the antibacterial food packaging film for fresh fruits and vegetables, 45 g of nano-zinc oxide, 10 g of nano-silver, and 45 g of nano-copper are weighed and uniformly mixed according to the mass ratio of 45:10:45 of nano-zinc oxide, nano-silver, and nano-copper, 4% of the total mass of the three, i.e. 4 g of silane coupling agent, is then added, the mixture is put into a high-speed mixer, the rotating speed is set to 750 r / min, the heating temperature is set to 105℃, and the mixture is continuously mixed for 25 min to ensure that the components are fully fused, and then the mixture is put into an airflow pulverizer for pulverization, and is sieved through a 1200-mesh standard sieve to collect the antibacterial functional nanomaterial with a structure unit scale of 50 nm-500 nm, as shown in FIG. 1, which is suitable for the light and thin requirements of fresh packaging and does not affect the air permeability. Figure 1

[0034] A blister forming mold with a size of 30 cm x 20 cm is selected to adapt to the common fresh packaging box specifications in supermarkets, the blister forming mold is put into an ultrasonic cleaner with a power of 500 W, a neutral cleaning agent aqueous solution is added, and the blister forming mold is cleaned for 12 min to remove the oil stains and metal debris remaining on the inner surface of the blister forming mold during the processing, the surface water is drained after cleaning, and the blister forming mold is dried in an electric heating constant temperature drying oven at 70℃ for 2.5 h to ensure that the inner surface of the blister forming mold is clean, free of impurities, and free of water residue, thereby providing a stable substrate for subsequent attachment of the antibacterial layer.

[0035] 20 g of the antibacterial functional nanomaterial is weighed, 300 g of deionized water is added, and then 20.4 g of an emulsifier is added, the emulsifier is polyglycerol fatty acid ester, which can improve the dispersion stability of the antibacterial material in water and adapt to the light and thin forming requirements of the fresh packaging film, the mixed system is placed in a high-speed dispersing machine and continuously emulsified at a rotating speed of 1500 r / min for 25 min to prepare a uniform and stable antibacterial nanomaterial emulsion, the air spray machine is used to uniformly coat the inner surface of the pretreated blister forming mold at a spraying pressure of 0.3 MPa, and the blister forming mold is moved into a drying oven at 80℃ for 50 min to bake and dry, thereby forming a dense antibacterial nanomaterial layer with a thickness of about 10 μm on the inner surface of the blister forming mold, as shown in FIG. 2, which ensures the antibacterial effect and does not affect the flexibility of the packaging film. Figure 2

[0036] ​​The polylactic acid, polybutylene adipate, and polybutylene adipate terephthalate are weighed according to a mass ratio of 50:25:25, which can balance the degradability and the flexibility of the plastic processing; the mixture is put into a double-screw extruder for mixing and granulation, and then a tablet press is used to press the polyester degradable plastic hard sheet material with a thickness of 0.3 mm and a melt index of 10 g / 10 min; the polyester degradable plastic hard sheet material is placed in the heating area of the blister machine, the heating temperature is set to 120 DEG C, and the material is kept soft for 3 min; then the softened polyester degradable plastic hard sheet material is covered on the surface of the blister forming mold with the antibacterial nano material layer, the vacuum device is started to keep the vacuum degree at-0.085 MPa for 2 min, so that the softened polyester degradable plastic hard sheet material is tightly attached to the surface of the blister forming mold, and then the vacuum device is turned off and naturally cooled to room temperature; after demolding, the antibacterial food packaging film suitable for fresh fruit and vegetable packaging is obtained.

[0037] Three 20 mm x 20 mm samples are cut from the demolded antibacterial food packaging film, placed in a high-pressure steam sterilization pot for sterilization for 20 min, and then placed in the center of LB medium plates containing Staphylococcus aureus and Escherichia coli, respectively, which are the most common pathogenic bacteria in the storage process of fresh fruits and vegetables; the samples are tightly attached to the medium by gently pressing with sterile tweezers; the LB medium plates are placed in a 37 DEG C constant temperature incubator for 24 h; after taking out, the width of the antibacterial zone around the sample is measured with a vernier caliper; the average antibacterial width of the three samples is 0.35 mm for Staphylococcus aureus and 0.48 mm for Escherichia coli, respectively, which meets the antibacterial and fresh-keeping requirements of fresh fruit and vegetable packaging.

[0038] In summary, for the packaging needs of fresh fruits and vegetables, the antibacterial functional nano material is prepared by compounding nano zinc oxide, nano silver, and nano copper, and adding a silane coupling agent to optimize the bonding performance of the material; the antibacterial material suitable for fresh packaging is obtained after synthesis by a solid phase method; the blister forming mold is cleaned and dried to provide a stable substrate for the attachment of the antibacterial layer; the polyglycerol fatty acid ester is used as an emulsifier to prepare an antibacterial nano material emulsion, which is sprayed and dried on the inner surface of the blister forming mold to form a dense antibacterial layer; the polyester degradable plastic hard sheet material is prepared by blending polylactic acid, polybutylene adipate, and polybutylene adipate terephthalate; the polyester degradable plastic hard sheet material is tightly combined with the antibacterial layer through the blister process; finally, the antibacterial food packaging film for fresh fruits and vegetables with the characteristics of lightness, breathability, antibacterial preservation, and degradability is prepared through antibacterial performance detection, which can effectively inhibit the common Staphylococcus aureus and Escherichia coli in the storage process of fresh fruits and vegetables.

[0039] Example Two:

[0040] In the preparation scene of the antibacterial food packaging film for cooked meat products, 60 g of nano-zinc oxide, 12 g of nano-silver, and 28 g of nano-copper are weighed, mixed according to the mass ratio of nano-zinc oxide, nano-silver, and nano-copper 60:12:28, 5% of the total mass of the three is added as a silane coupling agent, which is 5 g, and the addition amount can enhance the stability of the antibacterial material in the oil environment. The mixture is added to a high-speed mixer, set to 800 r / min and 110°C, and mixed for 28 min to ensure that the components are fully synergistic. After being crushed by an air flow crusher, it is sieved through a 1500 mesh standard sieve to obtain an antibacterial functional nanomaterial with a structure unit size of 80-800 nm, which meets the antibacterial strength requirements of cooked meat product packaging.

[0041] A 15 cm x 10 cm blister forming mold is selected, the blister forming mold is placed in an ultrasonic cleaner with a power of 550 W, and a cleaning agent aqueous solution is added for cleaning for 14 min. The oil stains and processing residues on the inner surface of the blister forming mold are thoroughly removed to avoid the influence of residual impurities on the adhesion effect of the antibacterial layer. After cleaning, the water stains on the surface of the blister forming mold are wiped dry, and the blister forming mold is placed in an electric heating drying oven at 75°C for drying for 2.8 h to ensure that the inner surface of the blister forming mold is free of impurities and moisture, meeting the strict cleanliness requirements of cooked meat product packaging.

[0042] Take 25 g of the prepared antibacterial functional nanomaterial, add 350 g of deionized water, and add 26.25 g of emulsifier, which is sucrose fatty acid ester. The emulsifier has strong stability in the oil environment and meets the packaging requirements of cooked meat products. The mixed system is placed in a high-speed emulsifier at a speed of 1600 r / min for 28 min to prepare a uniform emulsion. An air spray machine is used to uniformly coat the emulsion on the inner surface of the pretreated blister forming mold at a spraying pressure of 0.35 MPa. The pressure can ensure the density of the antibacterial layer. After coating, the blister forming mold is placed in an oven at 85°C for 55 min to form an antibacterial nanomaterial layer with a thickness of about 12 μm, which enhances the barrier effect on bacteria in the oil environment.

[0043] The polylactic acid, polybutylene adipate, and polybutylene adipate terephthalate are weighed according to a mass ratio of 60:20:20, which can improve the sealing property and grease resistance of the packaging film. After being mixed by a double-screw extruder, the polyester degradable plastic hard sheet material with a thickness of 0.25 mm and a melt index of 12 g / 10 min is pressed. The polyester degradable plastic hard sheet material is placed into a heat area of a blister machine, and the heating temperature is set to 125 ℃. The polyester degradable plastic hard sheet material is softened after being kept for 3.5 min. The softened polyester degradable plastic hard sheet material is covered on the surface of a blister forming mold with an antibacterial nano material layer. A vacuum device is started, and the vacuum degree is kept at -0.088 MPa for 2.5 min to adsorb the polyester degradable plastic hard sheet material to the blister forming mold. After being naturally cooled to room temperature, the blister forming mold is demolded to obtain an antibacterial food packaging film suitable for cooked meat product packaging, as shown in Figure 3

[0044] Three 20 mm x 20 mm samples are cut from the obtained antibacterial food packaging film, sterilized by high-pressure steam for 20 min, and then placed in the center of a nutrient agar culture medium plate containing Staphylococcus aureus and Escherichia coli, respectively, so that the sample is tightly attached to the culture medium. After being cultured in a 37 ℃ constant temperature incubator for 36 h, the width of the antibacterial zone is measured by a vernier caliper. The average antibacterial width of the three samples is 0.38 mm for Staphylococcus aureus and 0.50 mm for Escherichia coli, respectively, which meets the antibacterial protection requirements for long-term storage of cooked meat products.

[0045] In summary, for the packaging requirements of cooked meat products, the antibacterial functional nano material is formed by compounding nano zinc oxide, nano silver, and nano copper, and the stability of the antibacterial material in the grease environment is enhanced by adding a silane coupling agent. The required antibacterial material is synthesized by a solid phase method. The blister forming mold is cleaned and dried, and sucrose fatty acid ester is selected as an emulsifier to prepare a stable emulsion. The dense antibacterial nano material layer suitable for the grease environment is formed by air spraying and baking. The polyester degradable plastic hard sheet material with sealing property and grease resistance is prepared by blending polylactic acid, polybutylene adipate, and polybutylene adipate terephthalate. The polyester degradable plastic hard sheet material is tightly attached to the antibacterial layer by the blister forming process. Finally, the antibacterial performance is detected to obtain the antibacterial food packaging film for cooked meat products, which has outstanding antibacterial performance, good sealing property, and degradability, and can meet the antibacterial protection requirements for long-term storage of cooked meat products.

[0046] ​The above merely describes the preferred embodiments of the present application, and is not intended to limit the present application in any form. Although the present application has been disclosed with the preferred embodiments as above, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to the above disclosed technical content to obtain equivalent embodiments with equivalent changes, as long as the changes or modifications do not deviate from the technical solution of the present application. Any modification, change, equivalent change and modification of the above embodiments made according to the technical essence of the present application still belong to the scope of the technical solution of the present application.

Claims

1. An antibacterial food packaging film, characterized in that, The packaging film includes: a polyester biodegradable plastic substrate; The polyester biodegradable plastic substrate is formed by vacuum forming process. The inner surface of the vacuum forming mold is coated with an antibacterial nanomaterial layer. The polyester biodegradable plastic substrate is a blend of polylactic acid, polybutylene adipate, and polybutylene adipate terephthalate. The mass ratio of each component of polylactic acid, polybutylene adipate, and polybutylene adipate in the blend is 40-60:20-35:15-30. The melt index of the blend is 5-15 g / 10 min. The antibacterial nanomaterial layer is composed of antibacterial functional nanomaterials synthesized by solid-phase method. The antibacterial functional nanomaterials are a compound of nano zinc oxide, nano silver, and nano copper. The mass ratio of the components of nano zinc oxide, nano silver, and nano copper in the compound is 40-70:5-15:20-45. After the components are mixed and reacted by solid-phase method, a uniform antibacterial functional body is formed. The steps of solid-phase method synthesis of antibacterial functional nanomaterials are as follows: nano zinc oxide, nano silver, and nano copper are mixed with a silane coupling agent in a certain proportion, and mixed for 20-30 min at a speed of 600-900 r / min and a temperature of 90-120℃. After air jet pulverization, the mixture is sieved to obtain antibacterial functional nanomaterials with a structural unit size of 10 nm-1 μm. The structural unit size of the antibacterial functional nanomaterials is 10 nm-1 μm. The antibacterial food packaging film has an inhibition width of ≥0.31mm against Staphylococcus aureus and ≥0.44mm against Escherichia coli.

2. The antibacterial food packaging film according to claim 1, characterized in that, The antibacterial functional nanomaterial compound contains a silane coupling agent, and the amount of the silane coupling agent added is 3%-6% of the total mass of the antibacterial functional nanomaterial.

3. A processing method for an antibacterial food packaging film, wherein the processing method is applicable to the antibacterial food packaging film according to any one of claims 1-2, characterized in that, The specific steps of this processing technology are as follows: Material synthesis: Nano zinc oxide, nano silver, and nano copper were taken in a mass ratio of 40-70:5-15:20-45, and 3-6% of silane coupling agent was added. Antibacterial functional nanomaterials were synthesized by solid-phase method. The synthesis parameters were adjusted to obtain antibacterial functional nanomaterials with structural unit scale of 10nm-1μm. Mold pretreatment: The vacuum forming mold is cleaned and dried to obtain a clean and impurity-free vacuum forming mold; Preparation of antibacterial layer: Antibacterial functional nanomaterials are added to deionized water, and emulsifiers are added to emulsify the mixture to obtain an emulsion. The emulsion is then coated onto the inner surface of a vacuum forming mold and dried to form an antibacterial nanomaterial layer. Vacuum forming: Polylactic acid, polybutylene adipate, and polybutylene adipate in a mass ratio of 40-60:20-35:15-30 are blended to form a polyester biodegradable plastic rigid sheet with a melt index of 5-15 g / 10 min. After heating and softening, the sheet is vacuum-adsorbed onto the surface of a vacuum forming mold with an antibacterial nanomaterial layer. After cooling, the sheet is demolded to obtain an antibacterial food packaging film. Performance testing: Take antibacterial food packaging film, cut a sample with a size of 20mm×20mm, and test its antibacterial performance against Staphylococcus aureus and Escherichia coli.

4. The processing technology of an antibacterial food packaging film according to claim 3, characterized in that, In the mold pretreatment, the steps of the vacuum forming mold pretreatment are as follows: use an ultrasonic cleaner to clean the vacuum forming mold for 10-15 minutes with a cleaning power of 400-600W, and after cleaning, place the vacuum forming mold in a drying oven at 60-80℃ for 2-3 hours to dry.

5. The processing technology of an antibacterial food packaging film according to claim 3, characterized in that, In the preparation of the antibacterial layer, the emulsifier is polyglycerol fatty acid ester or sucrose fatty acid ester, and the amount of emulsifier added is 5-8% of the total mass of the antibacterial functional nanomaterials and deionized water. The stirring speed of the emulsification treatment is 1200-1800 r / min, and the emulsification time is 20-30 min. The coating is carried out by air spraying, with a spraying pressure of 0.2-0.4 MPa, a drying temperature of 70-90℃, and a drying time of 40-60 min.

6. The processing technology of an antibacterial food packaging film according to claim 3, characterized in that, In the vacuum forming process, the heating temperature of the polyester biodegradable plastic rigid sheet is 110-130℃, and the holding time is 2-4 min; the vacuum degree of vacuum adsorption is -0.08MPa to -0.09MPa, the adsorption time is 1-3 min, and the cooling process is natural cooling to room temperature.

7. The processing technology of an antibacterial food packaging film according to claim 3, characterized in that, In the performance testing, the antibacterial performance testing steps are as follows: After sterilization, the sample is placed in the center of a culture medium plate containing Staphylococcus aureus or Escherichia coli, and the sample is in close contact with the culture medium. After incubation at a constant temperature of 37°C for 24-48 hours, the width of the inhibition zone around the sample is measured. The inhibition width against Staphylococcus aureus is ≥0.31 mm, and the inhibition width against Escherichia coli is ≥0.44 mm.

Images