Antibacterial packaging material as well as preparation method and application thereof

Abstract

The invention discloses an antibacterial packaging material as well as a preparation method and application thereof. The antibacterial packaging material is prepared from pineapple leaf fiber carboxymethyl cellulose, carboxymethyl cellulose, cationic starch, 3-hydroxyl octoate, alpha-tocopherol, dimethylbiguanide hydrochloride, a plasticizer, nitrogen-doped carbon quantum dots, plant essential oil, nano zeolite powder, carvacrol and citric acid. The preparation method comprises the following steps: dispersing the cationic starch in the deionized water, dispersing the pineapple leaf fiber carboxymethyl cellulose and carboxymethyl cellulose in the deionized water, completely dissolving, adding into a starch solution, sequentially adding the rest components, uniformly mixing, heating, reacting, forming a film, and drying to obtain the packaging material. According to the antibacterial packaging material, the cationic starch, the carbon quantum dots, the plant essential oil and other related components are combined for the first time to form a novel antibacterial packaging material, the antibacterial performance is remarkably improved and kept for a long time through the synergistic effect of all the components, and the antibacterial packaging material is high in material stability, simple and convenient in preparation process, low in cost and high in application and popularization value.

Description

Technical Field

[0001] The present invention relates to the technical field of packaging materials, and more particularly to an antibacterial packaging material and a preparation method and application thereof. Background Art

[0002] In the field of food packaging, traditional antibacterial packaging materials mostly rely on chemically synthesized antibacterial agents, such as silver ions and titanium dioxide. Although these materials can effectively inhibit the growth of microorganisms to a certain extent, chemically synthesized antibacterial agents are difficult to biodegrade and will have an adverse impact on the environment. In addition, since traditional antibacterial agents are difficult to stably exist in complex food environments, they will enter food over time, not only contaminating food, but also significantly reducing the antibacterial effect over time. Long-term contact or ingestion of food packaged with chemical antibacterial materials will pose a potential threat to human health. It is also necessary to mention that although some high-end antibacterial materials are stable and safer, their production costs are high and the process is complex, which seriously limits their widespread application in the food packaging industry.

[0003] Therefore, how to develop a natural, degradable, stable and efficient antibacterial packaging material is an urgent problem to be solved by those skilled in the art. Summary of the invention

[0004] In view of this, the present invention provides an antibacterial packaging material, which adopts food-grade raw materials, undergoes a simple cross-linking process, and adds functional components to achieve a good and safe antibacterial effect.

[0005] To achieve the above object, the present invention adopts the following technical solution:

[0006] An antibacterial packaging material comprises the following components in parts by weight: 70-85 parts of pineapple leaf fiber carboxymethyl cellulose, 15-30 parts of carboxymethyl cellulose, 15-30 parts of cationic starch, 1-3 parts of 3-hydroxyoctanoate, 1-3 parts of alpha-tocopherol, 1-2 parts of dimethyl biguanide hydrochloride, 10-15 parts of plasticizer, 5-7 parts of nitrogen-doped carbon quantum dots, 2-4 parts of plant essential oil, 2-3 parts of nano zeolite powder, 0.5-1 part of carvacrol and 1-2 parts of citric acid.

[0007] Preferably, the preparation method of the pineapple leaf fiber carboxymethyl cellulose is as follows:

[0008] Step 1: crush the pineapple leaf fiber into 30 meshes, wash and dry it, disperse it in a 3 mol / L KOH aqueous solution, stir it for 24 hours, filter the sample and wash it until pH=7.0, dry it at 105°C, dissolve the dried sample in a 1 mol / L HCl aqueous solution, stir it for 8 hours, filter the sample and wash it until pH=7.0, and dry it at 105°C to obtain pineapple leaf fiber powder;

[0009] Step 2: adding 7% of NaOH by total weight to a solution with a volume ratio of isopropanol: water = 1:1, then adding 2% of pineapple leaf fiber powder by total weight to react for 20-60 minutes for activation, then adding 1% of epichlorohydrin by total weight for cross-linking, and finally adding 1% of sodium chloroacetate by total weight for carboxymethylation conversion, washing and drying, and obtaining pineapple leaf fiber carboxymethyl cellulose.

[0010] Preferably, the plasticizer is glycerol.

[0011] Preferably, the plant essential oil is one or more of cinnamon essential oil, sweet orange essential oil, camphor essential oil, peppermint essential oil, and garlic essential oil.

[0012] The present invention also provides a method for preparing the antibacterial packaging material as described in the above technical solution, comprising the following steps:

[0013] (1) dispersing cationic starch in deionized water to prepare a suspension, and then heating under stirring conditions to completely dissolve the starch to obtain a cationic starch solution;

[0014] (2) dispersing pineapple leaf fiber carboxymethyl cellulose and carboxymethyl cellulose in deionized water, stirring until completely dissolved, and then adding to the cationic starch solution prepared in step (1), mixing evenly, to obtain a composite membrane solution;

[0015] (3) adding 3-hydroxyoctanoate, α-tocopherol, dimethyl biguanide hydrochloride, plasticizer, nitrogen-doped carbon quantum dots, nano zeolite powder, plant essential oil and carvacrol to the composite membrane solution in sequence, mixing evenly, adding citric acid, homogenizing by high-pressure microfluidization, and then stirring under heating conditions for 1-2 hours, filtering and degassing by vacuum degassing machine for 0.5-2 hours to obtain a membrane-forming solution;

[0016] (4) Pour the film-forming liquid into a mold and obtain the antibacterial packaging material after drying.

[0017] Preferably, in step (1), the mass ratio of cationic starch to deionized water is 1:(1-2), the heating temperature is 45-50° C., and the time is 30-45 min.

[0018] Preferably, the ratio of the pineapple leaf fiber carboxymethyl cellulose and the carboxymethyl cellulose to deionized water in step (2) is 4-7 mg / ml.

[0019] Preferably, the heating temperature in step (3) is 60-65°C.

[0020] Preferably, the drying in step (4) is carried out by gradient temperature increase, first drying at 32-35°C for 3-4 hours, then heating to 40-50°C for drying for 24-36 hours.

[0021] In addition, the present invention also provides the use of the antibacterial packaging material or the antibacterial packaging material prepared by the method in food packaging.

[0022] It can be seen from the above technical solutions that, compared with the prior art, the present invention discloses an antibacterial packaging material and a preparation method and application thereof, which have the following beneficial effects:

[0023] In the antibacterial packaging material provided by the present invention, cationic starch and carboxymethyl cellulose are used as main raw materials, wherein cationic starch is used as the main material, has good biodegradability and film-forming performance, can quickly kill bacteria and viruses, and inhibit the growth and reproduction of fungi; pineapple leaf fiber carboxymethyl cellulose and carboxymethyl cellulose are used as thickeners and stabilizers, and are cross-linked with cationic starch under the action of a cross-linking agent to improve film-forming performance, increase the stability, mechanical strength and moisture retention capacity of the material, and at the same time promote the dispersion of mixed components in the preparation process, and effectively utilize agricultural waste; nitrogen-doped carbon quantum dots are added to the mixed material, and compared with simple carbon quantum dots, doped nitrogen atoms can improve the fluorescence quantum yield and emission intensity of the carbon quantum dots, thereby enhancing their bactericidal effect; 3-hydroxyoctanoate, α-tocopherol, and dimethylbiguanide hydrochloride all have good antibacterial properties. effect; the addition of glycerol can improve the compatibility of the system, and effectively improve the elongation at break and light transmittance of the material, and can also accelerate the degradation rate of the material, meeting the performance requirements of environmentally friendly food packaging materials; plant essential oils and carvacrol, as natural antibacterial ingredients, have broad-spectrum antibacterial activity against a variety of bacteria, and are safe and harmless to the human body; nano-zeolite powder enhances the antibacterial effect and fresh-keeping performance of the plastic wrap through its unique physical and chemical properties. It contains a variety of minerals, most of which exist in the form of oxides. After hydrolysis, they can release ions and be directly absorbed and utilized, thus having a good antibacterial effect, and can effectively adsorb and remove harmful substances through its reticular porous structure and ion exchange performance, thereby extending the shelf life of food. Nano-zeolite powder also has good mechanical properties and a large specific surface area, thereby enhancing the mechanical properties of the material, and is conducive to the adsorption of energy supply components and long-term sustained release. All ingredients of the antibacterial packaging material of the present invention are derived from nature or bioremediation, which significantly reduces the environmental burden. For the first time, related components are combined to form a new antibacterial packaging material. Through the synergistic effect of each component, the antibacterial performance is significantly improved and maintained for a long time. The material has strong stability, simple preparation process, low cost, and high promotion and application value. DETAILED DESCRIPTION

[0024] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] The nitrogen-doped carbon quantum dots can be prepared by conventional methods in the prior art such as chemical vapor deposition, arc discharge, laser ablation or hydrothermal method.

[0026] The nitrogen-doped carbon quantum dots used in the following examples were prepared by a hydrothermal method, specifically, using citric acid as a carbon source and 3-dimethylaminopropylamine as a nitrogen doping agent, and were prepared under hydrothermal conditions at 180°C.

[0027] The preparation method of pineapple leaf fiber carboxymethyl cellulose is as follows:

[0028] Step 1: crush the pineapple leaf fiber into 30 meshes, wash and dry it, disperse it in a 3 mol / L KOH aqueous solution, stir it for 24 hours, filter the sample and wash it until pH=7.0, dry it at 105°C, dissolve the dried sample in a 1 mol / L HCl aqueous solution, stir it for 8 hours, filter the sample and wash it until pH=7.0, and dry it at 105°C to obtain pineapple leaf fiber powder;

[0029] Step 2: adding 7% of NaOH by total weight to a solution with a volume ratio of isopropanol: water = 1:1, then adding 2% of pineapple leaf fiber powder by total weight to react for 20-60 minutes for activation, then adding 1% of epichlorohydrin by total weight for cross-linking, and finally adding 1% of sodium chloroacetate by total weight for carboxymethylation conversion, washing and drying, and obtaining pineapple leaf fiber carboxymethyl cellulose.

[0030] Example 1

[0031] The antibacterial packaging material comprises the following components in parts by weight: 70 parts of pineapple leaf fiber carboxymethyl cellulose, 15 parts of carboxymethyl cellulose, 30 parts of cationic starch, 1 part of 3-hydroxyoctanoate, 3 parts of α-tocopherol, 1 part of dimethyl biguanide hydrochloride, 12 parts of glycerol, 5 parts of nitrogen-doped carbon quantum dots, 4 parts of cinnamon essential oil, 3 parts of nano zeolite powder, 0.5 part of carvacrol, and 1 part of citric acid.

[0032] The method for preparing the antibacterial packaging material comprises the following steps:

[0033] (1) dispersing cationic starch in deionized water to prepare a suspension, wherein the mass ratio of cationic starch to deionized water is 1:1, and then heating to 48° C. under stirring for 35 minutes to completely dissolve the cationic starch to obtain a starch solution;

[0034] (2) dispersing pineapple leaf fiber carboxymethyl cellulose and carboxymethyl cellulose in deionized water, stirring until completely dissolved, wherein the ratio of pineapple leaf fiber carboxymethyl cellulose and carboxymethyl cellulose to deionized water is 4 mg / mL, and then adding to the starch solution prepared in step (1), mixing evenly, to obtain a composite membrane solution;

[0035] (3) 3-hydroxyoctanoate, α-tocopherol, dimethyl biguanide hydrochloride, glycerol, nitrogen-doped carbon quantum dots, nano zeolite powder, cinnamon essential oil and carvacrol were added to the composite membrane solution in sequence, mixed evenly, and then citric acid was added. The mixture was homogenized by high-pressure microfluidization, and then heated to 65° C. and stirred for 1 h. After filtering, the membrane-forming solution was degassed by a vacuum degassing machine for 1 h.

[0036] (4) The film-forming liquid is poured into a mold for forming, and then placed in a dryer and subjected to a gradient temperature increase treatment, first dried at 35° C. for 3 h, then heated to 50° C. for 24 h, and the antibacterial packaging material is obtained after drying.

[0037] Example 2

[0038] The antibacterial packaging material comprises the following components in parts by weight: 75 parts of pineapple leaf fiber carboxymethyl cellulose, 20 parts of carboxymethyl cellulose, 25 parts of cationic starch, 2 parts of 3-hydroxyoctanoate, 2 parts of α-tocopherol, 1 part of dimethyl biguanide hydrochloride, 10 parts of glycerol, 6 parts of nitrogen-doped carbon quantum dots, 3 parts of peppermint essential oil, 3 parts of nano zeolite powder, 1 part of carvacrol, and 2 parts of citric acid.

[0039] The method for preparing the antibacterial packaging material comprises the following steps:

[0040] (1) dispersing cationic starch in deionized water to prepare a starch suspension, wherein the mass ratio of cationic starch to deionized water is 1:1.5, and then heating to 45° C. under stirring for 45 minutes to completely dissolve the cationic starch to obtain a starch solution;

[0041] (2) dispersing pineapple leaf fiber carboxymethyl cellulose and carboxymethyl cellulose in deionized water, stirring until completely dissolved, wherein the ratio of pineapple leaf fiber carboxymethyl cellulose and carboxymethyl cellulose to deionized water is 6 mg / mL, and then adding to the starch solution prepared in step (1), mixing evenly, to obtain a composite membrane solution;

[0042] (3) 3-hydroxyoctanoate, α-tocopherol, dimethyl biguanide hydrochloride, glycerol, nitrogen-doped carbon quantum dots, nano zeolite powder, peppermint essential oil and carvacrol were added to the composite membrane solution in sequence, mixed evenly, and then citric acid was added. The mixture was homogenized by high-pressure microfluidization, and then heated to 63° C. and stirred for 1.5 h. After filtering, the membrane-forming solution was degassed in a vacuum degasser for 2 h.

[0043] (4) The film-forming liquid is poured into a mold for forming, and then placed in a dryer and subjected to a gradient temperature treatment, first dried at 35° C. for 3 h, then heated to 40° C. for 36 h, and the antibacterial packaging material is obtained after drying.

[0044] Example 3

[0045] The antibacterial packaging material comprises the following components in parts by weight: 80 parts of pineapple leaf fiber carboxymethyl cellulose, 25 parts of carboxymethyl cellulose, 20 parts of cationic starch, 3 parts of 3-hydroxyoctanoate, 1 part of α-tocopherol, 2 parts of dimethyl biguanide hydrochloride, 14 parts of glycerol, 7 parts of nitrogen-doped carbon quantum dots, 4 parts of sweet orange essential oil, 3 parts of nano zeolite powder, 0.5 parts of carvacrol, and 2 parts of citric acid.

[0046] The method for preparing the antibacterial packaging material comprises the following steps:

[0047] (1) dispersing cationic starch in deionized water to prepare a starch suspension, wherein the mass ratio of cationic starch to deionized water is 1:1, and then heating to 48° C. under stirring for 40 minutes to completely dissolve the cationic starch to obtain a starch solution;

[0048] (2) dispersing pineapple leaf fiber carboxymethyl cellulose and carboxymethyl cellulose in deionized water, stirring until completely dissolved, wherein the ratio of pineapple leaf fiber carboxymethyl cellulose and carboxymethyl cellulose to deionized water is 6 mg / mL, and then adding to the starch solution prepared in step (1), mixing evenly, to obtain a composite membrane solution;

[0049] (3) 3-hydroxyoctanoate, α-tocopherol, dimethyl biguanide hydrochloride, glycerol, nitrogen-doped carbon quantum dots, nano zeolite powder, sweet orange essential oil and carvacrol were added to the composite membrane solution in sequence, mixed evenly, and then citric acid was added. The mixture was homogenized by high-pressure microfluidization, and then heated to 63° C. and stirred for 1.8 h. After filtering, the membrane-forming solution was degassed by a vacuum degassing machine for 1.2 h.

[0050] (4) The film-forming liquid is poured into a mold for forming, and then placed in a dryer and subjected to a gradient temperature treatment, first dried at 33° C. for 4 h, then heated to 50° C. for 30 h, and the antibacterial packaging material is obtained after drying.

[0051] Example 4

[0052] The antibacterial packaging material comprises the following components in parts by weight: 85 parts of pineapple leaf fiber carboxymethyl cellulose, 15 parts of carboxymethyl cellulose, 15 parts of cationic starch, 2 parts of 3-hydroxyoctanoate, 2 parts of α-tocopherol, 2 parts of dimethyl biguanide hydrochloride, 15 parts of glycerol, 7 parts of nitrogen-doped carbon quantum dots, 4 parts of garlic essential oil, 3 parts of nano zeolite powder, 1 part of carvacrol, and 1.5 parts of citric acid.

[0053] The method for preparing the antibacterial packaging material comprises the following steps:

[0054] (1) dispersing cationic starch in deionized water to prepare a starch suspension, wherein the mass ratio of cationic starch to deionized water is 1:1.5, and then heating to 50° C. under stirring for 30 minutes to completely dissolve the cationic starch to obtain a starch solution;

[0055] (2) dispersing pineapple leaf fiber carboxymethyl cellulose and carboxymethyl cellulose in deionized water, stirring until completely dissolved, wherein the ratio of pineapple leaf fiber carboxymethyl cellulose and carboxymethyl cellulose to deionized water is 7 mg / mL, and then adding the mixture to the starch solution prepared in step (1), mixing evenly, to obtain a composite membrane solution;

[0056] (3) 3-hydroxyoctanoate, α-tocopherol, dimethyl biguanide hydrochloride, glycerol, nitrogen-doped carbon quantum dots, nano zeolite powder, garlic essential oil and carvacrol were added to the composite membrane solution in sequence, mixed evenly, and then citric acid was added. The mixture was homogenized by high-pressure microfluidization, and then heated to 65° C. and stirred for 2 h. After filtering, the membrane-forming solution was degassed in a vacuum degasser for 2 h.

[0057] (4) The film-forming liquid is poured into a mold for forming, and then placed in a dryer and subjected to a gradient temperature increase treatment, first dried at 35° C. for 3 h, then heated to 0° C. and dried for 36 h, to obtain an antibacterial packaging material.

[0058] Comparative Example 1

[0059] The difference from Example 4 is that no nitrogen-doped carbon quantum dots are added.

[0060] Comparative Example 2

[0061] The difference from Example 4 is that garlic essential oil is not added.

[0062] Comparative Example 3

[0063] The difference from Example 4 is that no nano zeolite powder is added.

[0064] Comparative Example 4

[0065] The difference from Example 4 is that carvacrol was not added.

[0066] Comparative Example 5

[0067] The difference from Example 4 is that corn starch is used as starch.

[0068] Comparative Example 6

[0069] The difference from Example 4 is that 3-hydroxyoctanoate is not added.

[0070] Comparative Example 7

[0071] The difference from Example 4 is that α-tocopherol was not added.

[0072] Comparative Example 8

[0073] The difference from Example 4 is that dimethylbiguanide hydrochloride is not added.

[0074] Experimental example

[0075] The packaging materials prepared in Examples 1-4 and Comparative Examples 1-8 were respectively tested for antibacterial rate. The method for testing the antibacterial rate was based on QB / T2591-2003 "Antibacterial Plastics - Antibacterial Performance Test Method and Antibacterial Effect". Each sample was tested 10 times and the results were averaged. The experimental data are shown in the table below.

[0076]

[0077] By comparing the data of Examples 1-4 with the data of Comparative Examples 1-4, it can be found that the packaging material prepared by the ingredients and method in the present application has a high antibacterial rate, can achieve a good antibacterial effect, and has good performance.

[0078] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0079] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An antibacterial packaging material, characterized in that: The invention comprises the following components in parts by weight: 70-85 parts of pineapple leaf fiber carboxymethyl cellulose, 15-30 parts of carboxymethyl cellulose, 15-30 parts of cationic starch, 1-3 parts of 3-hydroxyoctanoate, 1-3 parts of alpha-tocopherol, 1-2 parts of dimethyl biguanide hydrochloride, 10-15 parts of plasticizer, 5-7 parts of nitrogen-doped carbon quantum dots, 2-4 parts of plant essential oil, 2-3 parts of nano zeolite powder, 0.5-1 parts of carvacrol and 1-2 parts of citric acid.

2. The antibacterial packaging material according to claim 1, characterized in that: The preparation method of the pineapple leaf fiber carboxymethyl cellulose is as follows: Step 1: crush the pineapple leaf fiber into 30 meshes, wash and dry it, disperse it in a 3 mol / L KOH aqueous solution, stir it for 24 hours, filter the sample and wash it until pH=7.0, dry it at 105°C, dissolve the dried sample in a 1 mol / L HCl aqueous solution, stir it for 8 hours, filter the sample and wash it until pH=7.0, and dry it at 105°C to obtain pineapple leaf fiber powder; Step 2: adding 7% of NaOH by total weight to a solution with a volume ratio of isopropanol: water = 1:1, then adding 2% of pineapple leaf fiber powder by total weight to react for 20-60 minutes for activation, then adding 1% of epichlorohydrin by total weight for cross-linking, and finally adding 1% of sodium chloroacetate by total weight for carboxymethylation conversion, washing and drying, and obtaining pineapple leaf fiber carboxymethyl cellulose.

3. The antibacterial packaging material according to claim 1, characterized in that: The plasticizer is glycerol.

4. The antibacterial packaging material according to claim 1, characterized in that: The plant essential oil is one or more of cinnamon essential oil, sweet orange essential oil, camphor essential oil, peppermint essential oil and garlic essential oil.

5. A method for preparing the antibacterial packaging material according to any one of claims 1 to 4, characterized in that: The following steps are involved: (1) dispersing cationic starch in deionized water to prepare a suspension, and then heating under stirring conditions to completely dissolve the starch to obtain a cationic starch solution; (2) dispersing pineapple leaf fiber carboxymethyl cellulose and carboxymethyl cellulose in deionized water, stirring until completely dissolved, and then adding to the cationic starch solution prepared in step (1), mixing evenly, to obtain a composite membrane solution; (3) adding 3-hydroxyoctanoate, α-tocopherol, dimethyl biguanide hydrochloride, plasticizer, nitrogen-doped carbon quantum dots, nano zeolite powder, plant essential oil and carvacrol to the composite membrane solution in sequence, mixing evenly, adding citric acid, homogenizing by high-pressure microfluidization, and then stirring under heating conditions for 1-2 hours, filtering and degassing by vacuum degassing machine for 0.5-2 hours to obtain a membrane-forming solution; (4) Pour the film-forming liquid into a mold and obtain the antibacterial packaging material after drying.

6. The method for preparing an antibacterial packaging material according to claim 5, characterized in that: In step (1), the mass ratio of cationic starch to deionized water is 1:(1-2), the heating temperature is 45-50° C., and the time is 30-45 min.

7. The method for preparing an antibacterial packaging material according to claim 5, characterized in that: The ratio of pineapple leaf fiber carboxymethyl cellulose and carboxymethyl cellulose to deionized water in step (2) is 4-7 mg / ml.

8. The method for preparing an antibacterial packaging material according to claim 5, characterized in that: The heating temperature in step (3) is 60-65°C.

9. The method for preparing an antibacterial packaging material according to claim 5, characterized in that: The drying in step (4) is carried out by gradient temperature increase, first drying at 32-35°C for 3-4h, then heating to 40-50°C for drying for 24-36h.

10. Use of the antibacterial packaging material according to any one of claims 1 to 4 or the antibacterial packaging material prepared by the method according to any one of claims 5 to 9 in food packaging.

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