A packaging surface material with antibacterial effect and preparation method thereof

Abstract

The present invention provides a packaging surface material with antibacterial effect and a preparation method thereof, and relates to the field of material technology. The packaging surface material of the present invention comprises, from top to bottom, a sealing film, a coating layer 1, a non-woven fabric or a woven fabric, a coating layer 2, an aluminum film and an antibacterial coating layer; the antibacterial component is a silver particle antibacterial masterbatch, which comprises silver-loaded calcium carbonate powder, a compatibilizer and a resin. The preparation method thereof is as follows: the silver-loaded calcium carbonate powder is granulated with a compatibilizer and a resin to obtain a silver particle antibacterial masterbatch; low-density polyethylene 1c7a is mixed with a coating-grade polypropylene resin to obtain a composite material; the mixture is an adhesive to bond the sealing layer and the non-woven fabric to obtain a three-layer composite cloth; the mixture is an adhesive to bond the aluminum film and the three-layer composite cloth to obtain a five-layer composite cloth; the mixture is mixed with the silver particle antibacterial masterbatch, extruded into a film, and coated on the five-layer composite cloth. The present invention achieves the technical effect of significantly improving the antibacterial property of the packaging surface material under the premise of adding a small amount of antibacterial components.

Description

Technical Field

[0001] The invention relates to the technical field of materials, and in particular to a packaging surface material with antibacterial effect and a preparation method thereof. Background Art

[0002] Food is particularly susceptible to bacterial contamination and spoilage during storage. The bacterial flora present in the food supply chain is complex, some of which are highly pathogenic and pose significant risks to human health. Food packaging refers to the general term for containers, materials and auxiliary materials used to protect products during food circulation, facilitate storage and transportation, and promote sales. Due to the diversity of application scenarios, such as picnics, take-out, and bento, people are accustomed to processing some food in advance, putting it in disposable lunch boxes and then putting it in handbags for easy carrying. However, during the storage process, some food may rot or deteriorate, which not only loses the nutrients in the food, but also has a negative impact on human health if eaten by mistake.

[0003] Chinese patent CN 102963073 A discloses a heat-insulating and cold-insulating composite material, which is composed of OPP printed film, LDPE layer, non-woven fabric, EPE layer and aluminum-plated film from top to bottom. Compared with the prior art, it has the following advantages: good heat-insulating and cold-insulating performance, wide range of use, can be made into insulation cups or cold-insulating cups, insulation bags or cold-insulating bags, insulation bags or cold-insulating bags, can keep hot food warm in winter, can keep cold food cold in summer, can also be used to hold items, play a role of heat-insulating and cold-insulating. However, it does not have antibacterial effect and cannot meet consumers' requirements for food preservation.

[0004] Food packaging can protect and prolong the shelf life. As consumers demand products that are minimally processed and preservative-free, researchers in this field are increasingly looking to develop materials with film-forming and antimicrobial properties that can improve food safety and extend food storage life. Antimicrobial packaging is one of the most promising active packaging systems that has been found to effectively kill and inhibit spoilage bacteria and pathogenic microorganisms. The main goal of antimicrobial packaging systems is to provide food with safety and quality assurance and an extended shelf life.

[0005] Chinese patent CN 103600915 A discloses an antibacterial packaging paper, comprising: an antibacterial layer, a paper layer, an adhesive layer, a filter membrane layer and a flame retardant layer, wherein the antibacterial layer is connected to the paper layer; the paper layer is connected to the adhesive layer; the adhesive layer is connected to the filter membrane layer; and the filter membrane layer is connected to the flame retardant layer. However, its specific antibacterial ability is not recorded.

[0006] Chinese patent CN 106543540 A discloses a method for preparing a SiO2 silver-loaded mildew-proof fresh-keeping packaging bag, which belongs to the field of food packaging technology. With silver and SiO2 as the core antibacterial materials, silver ions are electrostatically adsorbed on the surface of SiO2 particles to form SiO2 silver-loaded antibacterial particles with dual antibacterial effects. Nano antibacterial particles are mixed with attapulgite, polyethylene plastic masterbatch, coupling agent, etc., and blown into a nano antibacterial composite film. The present invention adds dual-effect antibacterial SiO2 silver-loaded antibacterial particles to the main material polyethylene plastic masterbatch, wherein Ag can give the fresh-keeping bag a good inhibition of the reproduction of bacteria and fungi, and play a role in preservation and anticorrosion. Nano SiO2 particles can adjust O2 and CO2 in the packaging bag through silicon-oxygen bonds, thereby achieving the effect of preservation and water retention. However, its preparation process is complicated and not suitable for large-scale promotion.

[0007] In summary, the researchers of the present invention provide a packaging surface material with antibacterial effect and a preparation method thereof, which, from top to bottom, comprises OPP film, coating layer 1, non-woven fabric, coating layer 2, aluminum film and antibacterial coating layer. By optimizing the antibacterial coating layer, the prepared product significantly improves the antibacterial performance. Summary of the invention

[0008] In view of the above problems, the present invention provides a packaging surface material with antibacterial effect, which comprises, from top to bottom, an OPP film, a coating layer 1, a non-woven fabric, a coating layer 2, an aluminum film and an antibacterial coating layer. The multiple layers of surface material are combined together by lamination, and antibacterial components are added to the surface coating. By optimizing the components, proportions and preparation methods, less antibacterial agent is added to achieve a better antibacterial effect.

[0009] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0010] On the one hand, the present invention provides a packaging surface material with antibacterial effect, which comprises, from top to bottom, a sealing film, a coating layer 1, a non-woven fabric or a woven fabric, a coating layer 2, an aluminum film and an antibacterial coating layer; the antibacterial component is a silver particle antibacterial masterbatch, which includes silver-loaded calcium carbonate powder, a compatibilizer and a resin.

[0011] Preferably, the sealing film is selected from at least one of OPP film, BOPP film, CPP film and PET film; more preferably, the sealing film is OPP film.

[0012] Preferably, the non-woven fabric or woven fabric is a non-woven fabric; further preferably, the raw material of the non-woven fabric comprises polypropylene resin and filler; the mass ratio of the polypropylene resin to the filler is 3.5-4.5:1; more preferably, the mass ratio of the polypropylene resin to the filler is 4:1.

[0013] Preferably, the raw materials of the coating layer 1 and the coating layer 2 include low-density polyethylene 1c7a and coating-grade polypropylene resin;

[0014] Preferably, the melt flow rate of the coating-grade polypropylene resin is ≥60g / 10min;

[0015] Preferably, the mass ratio of the low-density polyethylene 1c7a to the coating-grade polypropylene resin is 1:3-5; further preferably, the mass ratio of the low-density polyethylene 1c7a to the coating-grade polypropylene resin is 1:4.

[0016] Preferably, the compatibilizer is maleic anhydride.

[0017] Preferably, the resin is polypropylene resin.

[0018] Preferably, the mass ratio of the silver-loaded calcium carbonate powder, the compatibilizer and the resin is 4-6:0.1-1:1; further preferably, the mass ratio of the silver-loaded calcium carbonate powder, the compatibilizer and the resin is 4-5:0.1-0.5:1; more preferably, the mass ratio of the silver-loaded calcium carbonate powder, the compatibilizer and the resin is 5:0.5:1.

[0019] In another aspect, the present invention provides a method for preparing the above-mentioned packaging surface material having an antibacterial effect, comprising the following steps:

[0020] S1: Sodium carbonate solution and calcium chloride solution are mixed, silver nitrate solution is added to obtain a precipitate, dried, and ground to obtain silver-loaded calcium carbonate powder;

[0021] S2: silver-loaded calcium carbonate powder, maleic anhydride and polypropylene resin are mixed and granulated to obtain silver antibacterial particle masterbatch; the silver content of the silver antibacterial particle masterbatch is 18%-35%;

[0022] S3: low-density polyethylene 1c7a is mixed with coating-grade polypropylene resin to obtain a mixture, which is extruded into a film;

[0023] S4: Using the mixture of S3 as an adhesive to bond the sealing layer and the non-woven fabric to obtain a three-layer composite fabric;

[0024] S5: using the mixture of S3 as an adhesive to bond the aluminum film and the three-layer composite cloth obtained in S4 to obtain a five-layer composite cloth;

[0025] S6: The mixed material of S3 is mixed with the silver antibacterial masterbatch of S2, and extruded into a film to obtain an antibacterial coating layer;

[0026] S7: Applying an antibacterial coating layer on the five-layer composite fabric.

[0027] Preferably, the mass fraction of the sodium carbonate solution in S1 is 12%-18%;

[0028] Preferably, the mass fraction of the calcium chloride solution described in S1 is 12%-18%;

[0029] Preferably, the volume ratio of the sodium carbonate solution to the calcium chloride solution in S1 is 1:1-1.2; further preferably, the volume ratio of the sodium carbonate solution to the calcium chloride solution in S1 is 1:1.

[0030] Preferably, the mass fraction of the silver nitrate solution in S1 is 15%-25%;

[0031] Preferably, the volume ratio of the sodium carbonate solution to the silver nitrate solution in S1 is 1:1-1.5;

[0032] Preferably, the drying temperature in S1 is 100-120°C; further preferably, the drying temperature in S1 is 100-110°C; more preferably, the drying temperature in S1 is 110°C.

[0033] Preferably, the silver content in the silver antibacterial masterbatch described in S2 is 20%-30%.

[0034] Preferably, the specific parameters of the extrusion described in S3 are: the temperature of the extruder is 160-180° C., and the extrusion pressure is 60-80 MPa.

[0035] Preferably, the mass ratio of the mixture of S3 described in S6 to the silver particle antibacterial masterbatch of S2 is 1:1-1.2; further preferably, the mass ratio of the mixture of S3 described in S6 to the silver particle antibacterial masterbatch of S2 is 1:1.

[0036] Preferably, the specific parameters of the extrusion described in S6 are: the temperature of the extruder is 180-220° C., and the extrusion pressure is 45-60 MPa.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The technical solution of the present invention prepares the antibacterial component with silver-loaded calcium carbonate powder, a compatibilizer and a resin, and makes an antibacterial coating layer. By optimizing the components, ratios and preparation methods, the technical effect of significantly improving the antibacterial properties of the packaging surface material under the premise of adding a small amount of antibacterial components is achieved, which meets the market demand for improving the antibacterial performance of food packaging and is suitable for large-scale promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic diagram of the structure of the packaging surface material prepared in Example 1; from left to right corresponds to the order of the packaging surface material from top to bottom. DETAILED DESCRIPTION

[0040] In order to make the technical means, creative features, purpose and effect of the present invention easy to understand, the present invention is further explained below in conjunction with specific embodiments, but the following embodiments are only preferred embodiments of the present invention, not all. Based on the embodiments in the implementation mode, other embodiments obtained by those skilled in the art without making creative work all belong to the protection scope of the present invention. It is worth noting that the raw materials used in the present invention are all common commercial products, and their sources are not specifically limited. The technology and scientific terms used in the embodiments have the meanings commonly understood by those of ordinary skill in the art to which the present invention belongs.

[0041] Example 1

[0042] A method for preparing a packaging surface material with antibacterial effect comprises the following steps:

[0043] 1. A 12%wt sodium carbonate solution and a 16wt% calcium chloride solution are mixed in a volume ratio of 1:1, and a 22wt% silver nitrate solution is added during the formation of a precipitate, wherein the volume ratio of the sodium carbonate solution to the silver nitrate solution is 1:1.2; the precipitate is filtered and dried at 110°C, and then ground to obtain silver-loaded calcium carbonate powder.

[0044] 2. Silver-loaded calcium carbonate powder, maleic anhydride, and high melt index polypropylene resin were mixed in a mass ratio of 5:0.5:1, and granulated by a twin-screw granulator to obtain silver particle antibacterial masterbatch, in which the silver content was 28%.

[0045] 3. Mix low-density polyethylene 1c7a and coating-grade polypropylene resin in a mass ratio of 1:4, and extrude into a film through a laminating machine. The extrusion temperature is 180°C and the extrusion pressure is 60MPa.

[0046] 4. Bond the OPP film and the non-woven fabric on a laminating machine through the mixture in step 3 to obtain a three-layer composite fabric;

[0047] 5. The aluminum film and the composite cloth obtained in step 4 are bonded on a laminating machine through the mixture in step 3, and the aluminum film is laminated to one side of the non-woven fabric to obtain a five-layer composite cloth;

[0048] 6. Low-density polyethylene 1c7a, coating-grade polypropylene resin and silver ion antibacterial masterbatch were sheared at 35°C for 30 minutes and extruded into film through a laminating machine at a mass ratio of 1:4:1; the extrusion temperature was 200°C and the extrusion pressure was 45MPa;

[0049] 7. Coat the film obtained in step 6 on the five-layer composite cloth, and laminate the film to the aluminum film to obtain a six-layer composite surface material.

[0050] Comparative Example 1

[0051] A method for preparing a packaging surface material with antibacterial effect comprises the following steps:

[0052] Compared with Example 1, only the ratio of sodium carbonate solution, calcium chloride solution and silver nitrate solution is changed, specifically:

[0053] 1. Mix 12%wt sodium carbonate solution and 16wt% calcium chloride solution in a volume ratio of 1:1, add 22wt% silver nitrate solution in the process of generating precipitation, the volume ratio of sodium carbonate solution to silver nitrate solution is 1:2, filter the precipitate and dry it at 110°C, and grind it to obtain silver-loaded calcium carbonate powder.

[0054] The rest is the same as Example 1.

[0055] Comparative Example 2

[0056] A method for preparing a packaging surface material with antibacterial effect comprises the following steps:

[0057] Compared with Example 1, only the ratio of silver-loaded calcium carbonate powder, maleic anhydride, and high melt index polypropylene resin is changed, specifically:

[0058] 1. A 12%wt sodium carbonate solution and a 16wt% calcium chloride solution are mixed in a volume ratio of 1:1, and a 22wt% silver nitrate solution is added during the formation of a precipitate, wherein the volume ratio of the sodium carbonate solution to the silver nitrate solution is 1:1.2; the precipitate is filtered and dried at 110°C, and then ground to obtain silver-loaded calcium carbonate powder.

[0059] 2. Silver-loaded calcium carbonate powder, maleic anhydride, and high melt index polypropylene resin are mixed in a mass ratio of 10:1.5:2, and granulated by a twin-screw granulator to obtain silver particle antibacterial masterbatch with a silver content of 35%.

[0060] The rest is the same as Example 1.

[0061] Comparative Example 3

[0062] A method for preparing a packaging surface material with antibacterial effect comprises the following steps:

[0063] Compared with Example 1, only the antibacterial silver particle antibacterial masterbatch is replaced with the modified nano zinc oxide prepared in Example 2 of Chinese patent CN 113372650B, specifically:

[0064] The preparation method of the modified nano zinc oxide is as follows: 5 parts by weight of 3-(2-aminoethylamine)propyltriethoxysilane is added to 150 parts by weight of an 80wt% ethanol aqueous solution, and after stirring at a speed of 800 rpm for 3 minutes at room temperature, 100 parts by weight of nano zinc oxide is added, and then stirred at a speed of 1500 rpm for 90 minutes at 80°C. After the reaction is completed, centrifugation is performed and the precipitate is dried to obtain modified nano zinc oxide.

[0065] The rest is the same as Example 1.

[0066] Comparative Example 4

[0067] A method for preparing a packaging surface material with antibacterial effect comprises the following steps:

[0068] Compared with Example 1, only the antibacterial component silver particle antibacterial masterbatch is replaced with chitosan.

[0069] The rest is the same as Example 1.

[0070] Test Example 1

[0071] The antibacterial components prepared in Example 1 and Comparative Examples 1-4 were added to a mixture of beef extract peptone and E. coli, and samples were placed in culture dishes. The samples were compared with blank samples (without adding antibacterial components) to test their sterilization rates against E. coli. The results are shown in Table 1.

[0072] Table 1. Sterilization rate against Escherichia coli / %

[0073] Group Sterilization rate against Escherichia coli / % Example 1 85％ Comparative Example 1 29％ Comparative Example 2 38％ Comparative Example 3 35％ Comparative Example 4 31％ Blank 0％

[0074] Compared with Example 1, Comparative Example 1 changes the raw material ratio in the preparation process of silver-loaded calcium carbonate powder, Comparative Example 2 changes the ratio of silver-loaded calcium carbonate powder, maleic anhydride, and high melt index polypropylene resin, and Comparative Examples 3-4 change the antibacterial components. It can be seen from the data in Table 1 that the bactericidal rates of Comparative Examples 1-4 against Escherichia coli are significantly lower than those in Example 1, indicating that the silver particle antibacterial masterbatch prepared in Example 1 of the present invention has a significant antibacterial effect, and the specific components and ratios are conducive to improving the antibacterial performance.

[0075] Test Example 2

[0076] The surface materials prepared in Example 1 and Comparative Examples 1-4 were made into handbags and compared with blank samples (the antibacterial coating layer was replaced by the coating layer). The food shelf life of the handbags containing antibacterial ingredients was tested at 25°C.

[0077] Table 2. Food shelf life

[0078] Group Food shelf life / h Example 1 50h Comparative Example 1 12h Comparative Example 2 13h Comparative Example 3 18h Comparative Example 4 15h Blank 2h

[0079] Compared with Example 1, Comparative Example 1 changed the raw material ratio in the preparation process of silver-loaded calcium carbonate powder, Comparative Example 2 changed the ratio of silver-loaded calcium carbonate powder, maleic anhydride, and high melt index polypropylene resin, and Comparative Examples 3-4 changed the antibacterial components. It can be seen from the data in Table 1 that the extension time of the food shelf life of Comparative Examples 1-4 is lower than that of Example 1, indicating that the packaging surface material prepared in Example 1 of the present invention has a significant antibacterial effect, and the specific components and ratios are conducive to improving the antibacterial performance.

[0080] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A packaging surface material with antibacterial effect, characterized in that: The packaging surface material is composed of a sealing film, a coating layer 1, a non-woven fabric, a coating layer 2, an aluminum film and an antibacterial coating layer from top to bottom; The raw materials of the coating layer 1 and the coating layer 2 include low-density polyethylene 1c7a and coating-grade polypropylene resin; the mass ratio of the low-density polyethylene 1c7a to the coating-grade polypropylene resin is 1:3-5; The preparation method of the antibacterial coating layer is as follows: S1: Sodium carbonate solution and calcium chloride solution are mixed, silver nitrate solution is added to obtain a precipitate, dried, and ground to obtain silver-loaded calcium carbonate powder; The mass fraction of the sodium carbonate solution is 12%-18%; The mass fraction of the calcium chloride solution is 12-18%; The mass fraction of the silver nitrate solution is 15%-25%; The volume ratio of the sodium carbonate solution to the calcium chloride solution is 1:1-1.2; The volume ratio of the sodium carbonate solution to the silver nitrate solution is 1:1-1.5; S2: silver-loaded calcium carbonate powder, maleic anhydride and polypropylene resin are mixed and granulated to obtain silver antibacterial particle masterbatch; the silver content in the silver antibacterial particle masterbatch is 18%-35%; the mass ratio of the silver-loaded calcium carbonate powder, maleic anhydride and polypropylene resin is 4-6:0.1-1:1; Low-density polyethylene 1c7a is mixed with coating-grade polypropylene resin to obtain a mixture; the mixture is mixed with the silver particle antibacterial masterbatch S2, extruded into a film, and an antibacterial coating layer is obtained; The mass ratio of the mixture to the silver antibacterial masterbatch of S2 is 1:1-1.

2.

2. The method for preparing the packaging surface material with antibacterial effect according to claim 1, characterized in that: The following steps are involved: S1: Sodium carbonate solution and calcium chloride solution are mixed, silver nitrate solution is added to obtain a precipitate, dried, and ground to obtain silver-loaded calcium carbonate powder; S2: silver-loaded calcium carbonate powder, maleic anhydride and polypropylene resin are mixed and granulated to obtain silver antibacterial particle masterbatch; the silver content of the silver antibacterial particle masterbatch is 18%-35%; S3: low-density polyethylene 1c7a is mixed with coating-grade polypropylene resin to obtain a mixture, which is extruded into a film; S4: Using the mixture of S3 as an adhesive to bond the sealing layer and the non-woven fabric to obtain a three-layer composite fabric; S5: using the mixture of S3 as an adhesive to bond the aluminum film and the three-layer composite cloth obtained in S4 to obtain a five-layer composite cloth; S6: The mixed material of S3 is mixed with the silver antibacterial masterbatch of S2, and extruded into a film to obtain an antibacterial coating layer; S7: Applying an antibacterial coating layer on the five-layer composite fabric.

3. The preparation method according to claim 2, characterized in that: The specific parameters of the extrusion described in S3 are: the temperature of the extruder is 160-180°C, and the extrusion pressure is 60-80MPa; the specific parameters of the extrusion described in S6 are: the temperature of the extruder is 180-220°C, and the extrusion pressure is 45-60MPa.

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