Ultraviolet deoxidizing and fresh-keeping packaging material and application thereof

Abstract

The invention relates to an ultraviolet deoxidizing and fresh-keeping packaging material and application thereof, and belongs to the technical field of packaging materials. According to the invention, trimethylolpropane triacrylate and ethylenediamine are used as raw materials, a hyperbranched polymer with terminal double bonds is constructed based on Michael addition, then a sulfydryl-containing hindered amine light stabilizer obtained by ester exchange of methyl thioglycolate and pentamethylpiperidinol is added, and the hindered amine light stabilizer and alkyl mercaptan are subjected to a sulfydryl-alkene click reaction together. The light stabilizer and plastic are subjected to melt blending and then subjected to curtain coating to form a film to serve as an outer layer, and one face of the outer layer is coated with coating liquid prepared from a dispersing agent, PET, an active substance capable of generating triplet excitons under irradiation of ultraviolet light, an antioxidant, an ultraviolet light absorber and a stabilizer. When the ultraviolet deoxidization fresh-keeping packaging material is applied to packaging of articles, deoxidization can be achieved through irradiation of ultraviolet light, and the degradation effect of the ultraviolet light on the outer layer is very little.

Description

Technical Field

[0001] The invention belongs to the technical field of packaging materials, and in particular relates to an ultraviolet deoxygenation and fresh-keeping packaging material and application thereof. Background Art

[0002] At present, physical or chemical methods are mostly used for deoxygenation in the packaging of oxidizable items such as food and medicine. Physical deoxygenation is to create a low-oxygen or even oxygen-free environment through vacuum or nitrogen filling treatment, while chemical deoxygenation is to absorb oxygen by adding chemical deoxidizers. Both physical and chemical methods have problems such as high cost and complex operation. Based on this, a technology for deoxygenation is born by adding active substances that can generate triplet excitons under ultraviolet light to packaging materials. However, this technology still has certain disadvantages that limit its actual application effect. This is because in order for triplet excitons to better interact with oxygen in the bag, it is necessary to cover the surface of the packaging material with an additional layer of polymer film such as polypropylene film, polyethylene film, etc., so as to block the external oxygen. However, since ultraviolet light irradiation is a necessary condition in the actual deoxygenation process, this layer of polymer film will inevitably face degradation, that is, accelerated aging, and ultimately all performances are seriously affected, which directly restricts the overall packaging effect and shortens the service life, which is not worth the loss. Summary of the invention

[0003] In view of the problems existing in the prior art, the purpose of the present invention is to provide an ultraviolet deoxygenation fresh-keeping packaging material and its application. The present invention uses trimethylolpropane triacrylate and ethylenediamine as raw materials, constructs a terminal double-bond hyperbranched polymer based on Michael addition, then adds a mercapto-containing hindered amine light stabilizer obtained by ester exchange of methyl thioglycolate and pentamethylpiperidinol and alkyl mercaptan to carry out a mercapto-ene click reaction, thereby preparing a light stabilizer, which is melt-blended with plastic and then cast into a film as an outer layer, and a coating liquid prepared by coating one side of the outer layer with a dispersant, PET, an active substance that can generate triplet excitons when irradiated with ultraviolet light, an antioxidant, an ultraviolet light absorber and a stabilizer, and finally obtains an ultraviolet deoxygenation fresh-keeping packaging material after drying. When applied to the packaging of articles, not only can deoxygenation be achieved by irradiation with ultraviolet light, but also the degradation effect of the outer layer by ultraviolet light is minimal.

[0004] The purpose of the present invention can be achieved through the following technical solutions:

[0005] A method for preparing an ultraviolet deoxygenation fresh-keeping packaging material, the preparation method comprising the following steps:

[0006] (1) mixing the plastic and the light stabilizer at a mass ratio of 98-100:1 at 195-200° C. for 5-10 min, and casting the film into a film with a thickness of 10-15 μm using a casting machine to obtain an outer layer;

[0007] (2) mixing the dispersant, polyethylene terephthalate, active substance, antioxidant, ultraviolet light absorber and stabilizer in a mass ratio of 100:20:0.2-1.6:0.02-0.1:0.02-0.1:0.02-0.1 under ultrasound at 80-85° C. for 12-14 h to obtain a coating solution;

[0008] (3) The coating liquid is applied on one side of the outer layer and dried to complete the preparation.

[0009] As a preferred technical solution of the present invention, the light stabilizer in step (1) is prepared by the following steps:

[0010] Step A: adding ethylenediamine solution dropwise to trimethylolpropane triacrylate while stirring at 40-50° C., stirring at a constant temperature for 6-8 hours after the addition is completed, and distilling under reduced pressure to obtain component A; the ethylenediamine solution refers to a solution of ethylenediamine and methanol mixed at a mass ratio of 1:8-10 at room temperature; the molar ratio of the trimethylolpropane triacrylate to the ethylenediamine is 1:0.25-0.26;

[0011] Step B: adding 15-20 parts by weight of methyl thioglycolate, 3-4 parts by weight of pentamethylpiperidinol and 1-2 parts by weight of magnesium methoxide to 100 parts by weight of dimethyl sulfoxide, and then heating under reflux at 70-75° C. for 8-10 hours, purifying, and obtaining component B;

[0012] Step C: Add 4 parts by weight of component A, 2 parts by weight of component B, 1-1.5 parts by weight of alkyl mercaptan and 0.5 parts by weight of benzoin dimethyl ether to 100 parts by weight of dimethyl sulfoxide, then stir and mix for 1-1.5 hours under ultraviolet light irradiation at 30-35° C., cool to 0-5° C., filter, take the filter residue, wash with deionized water, and finally vacuum dry at 50-70° C. until constant weight, and the preparation is completed.

[0013] Furthermore, the dripping rate in step A is controlled at 1-2 drops / s.

[0014] Furthermore, the reduced pressure distillation in step A refers to distillation at 30° C. under a vacuum degree of -0.07 MPa until the volatiles are completely removed.

[0015] Furthermore, the purification in step B refers to first distilling at 60°C for 30-45min to remove volatiles, then distilling at 125-130°C for 60min to collect the fraction and cool it to room temperature, then adding 25-30 parts by weight of deionized water, filtering, taking the filter residue, washing it with deionized water, and finally vacuum drying it at 40-60°C until constant weight.

[0016] Furthermore, the alkyl mercaptan in step C is at least one of tetradecanethiol, hexadecanethiol and octadecanethiol.

[0017] Furthermore, the wavelength of the ultraviolet light in step C is 365nm.

[0018] As a preferred technical solution of the present invention, the working parameters of the casting machine in step (1) are that the die temperature is controlled at 190-200°C, and the cooling roller temperature is controlled at 30-35°C.

[0019] As a preferred technical solution of the present invention, the dispersant in step (2) is at least one of dimethyl isosorbide, tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide and dimethyl sulfoxide; the antioxidant is at least one of antioxidant 1076, antioxidant 1010 and antioxidant 264; the ultraviolet light absorber is at least one of phenyl o-hydroxybenzoate, resorcinol monobenzoate and hexamethylphosphoric acid triamide; and the stabilizer is at least one of zinc stearate, cadmium stearate and lead stearate.

[0020] As a preferred technical solution of the present invention, the active substance in step (2) is at least one of benzophenone, a benzophenone derivative and a β-diketone derivative.

[0021] As a preferred technical solution of the present invention, the power of the ultrasound in step (2) is 400W.

[0022] As a preferred technical solution of the present invention, the drying in step (3) refers to drying at 60-70° C. for 24 hours.

[0023] An ultraviolet deoxygenation fresh-keeping packaging material prepared by the preparation method as described above.

[0024] As a preferred technical solution of the present invention, the thickness of the ultraviolet deoxygenation fresh-keeping packaging material is 18-20 microns.

[0025] An application of an ultraviolet deoxygenation fresh-keeping packaging material, wherein the ultraviolet deoxygenation fresh-keeping packaging material is applied to the packaging of articles.

[0026] A method for deoxygenating an ultraviolet deoxygenation fresh-keeping packaging material, the deoxygenation method comprising the following steps:

[0027] The ultraviolet deoxygenation fresh-keeping packaging material is made into a bag, the articles are put into the bag, the bag is sealed, and then the bag is irradiated with ultraviolet light having a wavelength of 300-400nm for 30-60min.

[0028] Beneficial effects of the present invention:

[0029] (1) The present invention uses trimethylolpropane triacrylate and ethylenediamine as raw materials, constructs a double-bonded hyperbranched polymer based on Michael addition, and then adds a thiol-containing hindered amine light stabilizer obtained by ester exchange between methyl thioglycolate and pentamethylpiperidinol to carry out a thiol-ene click reaction with alkyl mercaptan, thereby preparing a light stabilizer, which is melt-blended with plastic and then cast into a film as an outer layer, and a coating liquid prepared by coating one side of the outer layer with a dispersant, PET, an active substance that can generate triplet excitons when irradiated with ultraviolet light, an antioxidant, an ultraviolet light absorber and a stabilizer, and finally obtains an ultraviolet deoxygenation fresh-keeping packaging material after drying. When used for packaging of articles, it can not only achieve deoxygenation through ultraviolet light irradiation, but also the degradation effect of the outer layer by ultraviolet light is minimal.

[0030] (2) The present invention creatively prepares a light stabilizer, which enables the outer layer of the ultraviolet deoxygenation fresh-keeping packaging material to have excellent anti-aging and anti-degradation capabilities when exposed to ultraviolet light. On the one hand, the light stabilizer is a hindered amine light stabilizer, which itself cannot absorb ultraviolet rays, thereby effectively ensuring that the actual deoxygenation process can be carried out normally and efficiently. On the other hand, since the light stabilizer is prepared on the basis of a hyperbranched polymer, it not only has a high molecular weight, thereby achieving enhanced thermal stability and reduced precipitation in the polymer matrix, but also retains a spherical structure, and the molecular chain is not easy to entangle, thereby greatly improving the mass transfer and diffusion rate, and being able to obtain more excellent light stabilization activity. In addition, after being modified by a certain amount of alkyl mercaptan, the saturated hydrocarbon group of the alkyl mercaptan can have better interface compatibility with the plastic, thereby promoting the dispersion effect of the light stabilizer, thereby further improving the anti-aging and anti-degradation capabilities of the outer layer.

[0031] (3) When the ultraviolet deoxygenation fresh-keeping packaging material prepared by the present invention is used for packaging of articles, it can achieve deoxygenation only by being exposed to ultraviolet light. The specific principle is that the active substance absorbs photon energy and enters an excited state, and intersystem crossing occurs in the excited state to form triplet excitons. The triplet excitons have a long life and high energy. They can transfer energy with oxygen molecules, and excite the oxygen molecules from the ground state to the singlet state (singlet oxygen), thereby promoting the singlet oxygen to combine with other components in the ultraviolet deoxygenation fresh-keeping packaging material, and transforming them into harmless or inactive compounds, thereby finally achieving the purpose of deoxygenation.

[0032] (4) The UV deoxygenation fresh-keeping packaging material prepared by the present invention is particularly suitable for the packaging of easily oxidizable items such as food, cosmetics, and medicines. It is convenient to deoxygenate and has a significant deoxygenation effect, which effectively extends the shelf life of the items and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0034] Figure 1 This is a physical picture of the ultraviolet deoxygenation fresh-keeping packaging material prepared in Example 1 of the present invention during deoxygenation.

[0035] Figure 2 This is a comparison chart of the oxygen content in the bag of the ultraviolet deoxygenation fresh-keeping packaging material prepared in Example 1 of the present invention before and after ultraviolet light irradiation during deoxygenation.

[0036] Figure 3 This is a comparison chart of the oxygen content in the bag of the ultraviolet deoxygenation fresh-keeping packaging material prepared in Example 2 of the present invention before and after ultraviolet light irradiation during deoxygenation.

[0037] Figure 4 This is a comparison chart of the oxygen content in the bag of the ultraviolet deoxygenation fresh-keeping packaging material prepared in Example 3 of the present invention before and after ultraviolet light irradiation during deoxygenation.

[0038] Figure 5 This is a comparison chart of the oxygen content in the bag of the ultraviolet deoxygenation fresh-keeping packaging material prepared in Example 4 of the present invention before and after ultraviolet light irradiation during deoxygenation. DETAILED DESCRIPTION

[0039] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0040] The plastics in all the embodiments and comparative examples of the present invention are polypropylene, purchased from PetroChina Co., Ltd., model EPC30R-H; polyethylene terephthalate was purchased from Shanghai Xingxiang Plastics Co., Ltd., brand PET powder.

[0041] Example 1

[0042] A method for preparing an ultraviolet deoxygenation fresh-keeping packaging material, the preparation method comprising the following steps:

[0043] (1) mixing the plastic and the light stabilizer at a mass ratio of 98:1 at 195° C. for 5 min, and casting the film into a film with a thickness of 10 μm using a casting machine to obtain an outer layer;

[0044] (2) mixing a dispersant, polyethylene terephthalate, an active substance, an antioxidant, an ultraviolet light absorber, and a stabilizer in a mass ratio of 100:20:0.2:0.02:0.02:0.02 under ultrasonication at 80° C. for 12 h to obtain a coating solution;

[0045] (3) The coating liquid is applied on one side of the outer layer and dried to complete the preparation.

[0046] The light stabilizer in step (1) is prepared by the following steps:

[0047] Step A: adding ethylenediamine solution dropwise to trimethylolpropane triacrylate while stirring at 40° C., stirring at a constant temperature for 6 hours after the addition is completed, and distilling under reduced pressure to obtain component A; the ethylenediamine solution refers to a solution of ethylenediamine and methanol mixed at a mass ratio of 1:8 at room temperature; the molar ratio of the trimethylolpropane triacrylate to the ethylenediamine is 1:0.25;

[0048] Step B: adding 15 parts by weight of methyl thioglycolate, 3 parts by weight of pentamethylpiperidinol and 1 part by weight of magnesium methoxide to 100 parts by weight of dimethyl sulfoxide, and then heating under reflux at 70° C. for 8 hours to purify, thereby obtaining component B;

[0049] Step C: Add 4 parts by weight of component A, 2 parts by weight of component B, 1 part by weight of alkyl mercaptan and 0.5 parts by weight of benzoin dimethyl ether to 100 parts by weight of dimethyl sulfoxide, then stir and mix under ultraviolet light at 30°C for 1 hour, cool to 0°C, filter, take the filter residue, wash with deionized water, and finally vacuum dry at 50°C until constant weight, and the preparation is completed.

[0050] The rate of dripping in step A is controlled at 1 drop / s.

[0051] The reduced pressure distillation in step A refers to distillation at 30° C. under a vacuum degree of −0.07 MPa until the volatiles are completely removed.

[0052] The purification in step B refers to first distilling at 60°C for 30 minutes to remove volatiles, then distilling at 125°C for 60 minutes to collect the fraction and cool it to room temperature, then adding 25 parts by weight of deionized water, filtering, taking the filter residue, washing it with deionized water, and finally vacuum drying it at 40°C until constant weight.

[0053] The alkyl mercaptan in step C is tetradecanethiol.

[0054] The wavelength of the ultraviolet light in step C is 365nm.

[0055] The operating parameters of the casting machine in step (1) are that the die head temperature is controlled at 190° C. and the cooling roller temperature is controlled at 30° C.

[0056] In step (2), the dispersant is N,N-dimethylformamide; the antioxidant is antioxidant 1076; the ultraviolet light absorber is phenyl o-hydroxybenzoate; and the stabilizer is zinc stearate.

[0057] The active substance in step (2) is 4-methylbenzophenone.

[0058] The power of the ultrasound in step (2) is 400W.

[0059] The drying in step (3) refers to drying at 60° C. for 24 hours.

[0060] An ultraviolet deoxygenation fresh-keeping packaging material prepared by the preparation method as described above.

[0061] The thickness of the ultraviolet deoxygenation fresh-keeping packaging material is 18 microns.

[0062] An application of an ultraviolet deoxygenation fresh-keeping packaging material, wherein the ultraviolet deoxygenation fresh-keeping packaging material is applied to the packaging of articles.

[0063] A method for deoxygenating an ultraviolet deoxygenation fresh-keeping packaging material, the deoxygenation method comprising the following steps:

[0064] The ultraviolet deoxygenation fresh-keeping packaging material is made into a bag, the articles are put into the bag, the bag is sealed, and then the bag is irradiated with ultraviolet light having a wavelength of 365 nm for 30 minutes.

[0065] Example 2

[0066] Based on Example 1, 4-methylbenzophenone was replaced by p-bromobenzophenone of equal weight, and the rest remained unchanged.

[0067] Example 3

[0068] Based on Example 1, 4-methylbenzophenone was replaced by an equal weight of dibenzoylmethane, and the rest remained unchanged.

[0069] Example 4

[0070] Based on Example 1, 4-methylbenzophenone was replaced by an equal weight of 1-(4-hydroxyphenyl)-3-phenyl-1,3-propanedione, and the rest remained unchanged.

[0071] Example 5

[0072] A method for preparing an ultraviolet deoxygenation fresh-keeping packaging material, the preparation method comprising the following steps:

[0073] (1) mixing the plastic and the light stabilizer at a mass ratio of 100:1 at 200° C. for 10 min, and casting the film into a film with a thickness of 15 μm using a casting machine to obtain an outer layer;

[0074] (2) mixing a dispersant, polyethylene terephthalate, an active substance, an antioxidant, an ultraviolet light absorber, and a stabilizer in a mass ratio of 100:20:1.6:0.1:0.1:0.1 under stirring at 85° C. for 14 h in an ultrasonic bath to obtain a coating solution;

[0075] (3) The coating liquid is applied on one side of the outer layer and dried to complete the preparation.

[0076] The light stabilizer in step (1) is prepared by the following steps:

[0077] Step A: adding ethylenediamine solution dropwise to trimethylolpropane triacrylate while stirring at 50° C., stirring at a constant temperature for 8 hours after the addition is completed, and distilling under reduced pressure to obtain component A; the ethylenediamine solution refers to a solution of ethylenediamine and methanol mixed at a mass ratio of 1:10 at room temperature; the molar ratio of the trimethylolpropane triacrylate to the ethylenediamine is 1:0.26;

[0078] Step B: adding 20 parts by weight of methyl thioglycolate, 4 parts by weight of pentamethylpiperidinol and 2 parts by weight of magnesium methoxide to 100 parts by weight of dimethyl sulfoxide, and then heating under reflux at 75° C. for 10 hours for purification to obtain component B;

[0079] Step C: Add 4 parts by weight of component A, 2 parts by weight of component B, 1.5 parts by weight of alkyl mercaptan and 0.5 parts by weight of benzoin dimethyl ether to 100 parts by weight of dimethyl sulfoxide, and then stir and mix for 1.5 hours under ultraviolet light at 35°C, cool to 5°C, filter, take the filter residue, wash with deionized water, and finally vacuum dry at 70°C until constant weight, and the preparation is completed.

[0080] The dripping rate in step A is controlled at 2 drops / s.

[0081] The reduced pressure distillation in step A refers to distillation at 30° C. under a vacuum degree of −0.07 MPa until the volatiles are completely removed.

[0082] The purification in step B refers to first distilling at 60°C for 45 minutes to remove volatiles, then distilling at 130°C for 60 minutes to collect the fraction and cool it to room temperature, then adding 30 parts by weight of deionized water, filtering, taking the filter residue, washing it with deionized water, and finally vacuum drying it at 60°C until constant weight.

[0083] The alkyl mercaptan in step C is hexadecanethiol.

[0084] The wavelength of the ultraviolet light in step C is 365nm.

[0085] The operating parameters of the casting machine in step (1) are as follows: the die head temperature is controlled at 200° C., and the cooling roller temperature is controlled at 35° C.

[0086] In step (2), the dispersant is N,N-dimethylformamide; the antioxidant is antioxidant 1010; the ultraviolet light absorber is monobenzoic acid resorcinol ester; and the stabilizer is zinc stearate.

[0087] The active substance in step (2) is 4-methylbenzophenone.

[0088] The power of the ultrasound in step (2) is 400W.

[0089] The drying in step (3) refers to drying at 70° C. for 24 hours.

[0090] An ultraviolet deoxygenation fresh-keeping packaging material prepared by the preparation method as described above.

[0091] The thickness of the ultraviolet deoxygenation fresh-keeping packaging material is 20 microns.

[0092] An application of an ultraviolet deoxygenation fresh-keeping packaging material, wherein the ultraviolet deoxygenation fresh-keeping packaging material is applied to the packaging of articles.

[0093] A method for deoxygenating an ultraviolet deoxygenation fresh-keeping packaging material, the deoxygenation method comprising the following steps:

[0094] The ultraviolet deoxygenation fresh-keeping packaging material is made into a bag, the articles are put into the bag, the bag is sealed, and then the bag is irradiated with ultraviolet light having a wavelength of 365 nm for 60 minutes.

[0095] Example 6

[0096] A method for preparing an ultraviolet deoxygenation fresh-keeping packaging material, the preparation method comprising the following steps:

[0097] (1) mixing the plastic and the light stabilizer at a mass ratio of 99:1 at 198° C. for 8 min, and casting the film into a film with a thickness of 12 μm using a casting machine to obtain an outer layer;

[0098] (2) mixing a dispersant, polyethylene terephthalate, an active substance, an antioxidant, an ultraviolet light absorber, and a stabilizer in a mass ratio of 100:20:1:0.05:0.05:0.05 under stirring at 83° C. for 13 h in ultrasound to obtain a coating solution;

[0099] (3) The coating liquid is applied on one side of the outer layer and dried to complete the preparation.

[0100] The light stabilizer in step (1) is prepared by the following steps:

[0101] Step A: adding ethylenediamine solution dropwise to trimethylolpropane triacrylate while stirring at 45°C, continuing to stir at a constant temperature for 7 hours after the addition is completed, and distilling under reduced pressure to obtain component A; the ethylenediamine solution refers to a solution of ethylenediamine and methanol mixed at a mass ratio of 1:9 at room temperature; the molar ratio of the trimethylolpropane triacrylate to the ethylenediamine is 1:0.255;

[0102] Step B: adding 18 parts by weight of methyl thioglycolate, 3.5 parts by weight of pentamethylpiperidinol and 1.5 parts by weight of magnesium methoxide to 100 parts by weight of dimethyl sulfoxide, and then heating under reflux at 73° C. for 9 hours for purification to obtain component B;

[0103] Step C: Add 4 parts by weight of component A, 2 parts by weight of component B, 1.3 parts by weight of alkyl mercaptan and 0.5 parts by weight of benzoin dimethyl ether to 100 parts by weight of dimethyl sulfoxide, then stir and mix under ultraviolet light at 33° C. for 1.3 hours, cool to 3° C., filter, take the filter residue, wash with deionized water, and finally vacuum dry at 60° C. until constant weight, and the preparation is completed.

[0104] The rate of the dripping in step A is controlled at 1.5 drops / s.

[0105] The reduced pressure distillation in step A refers to distillation at 30° C. under a vacuum degree of −0.07 MPa until the volatiles are completely removed.

[0106] The purification in step B refers to first distilling at 60°C for 40 minutes to remove volatiles, then distilling at 128°C for 60 minutes to collect the fraction and cool it to room temperature, then adding 28 parts by weight of deionized water, filtering, taking the filter residue, washing it with deionized water, and finally vacuum drying it at 50°C until constant weight.

[0107] The alkyl mercaptan in step C is octadecyl mercaptan.

[0108] The wavelength of the ultraviolet light in step C is 365nm.

[0109] The operating parameters of the casting machine in step (1) are as follows: the die temperature is controlled at 195° C., and the cooling roller temperature is controlled at 33° C.

[0110] In step (2), the dispersant is N,N-dimethylformamide; the antioxidant is antioxidant 264; the ultraviolet light absorber is hexamethylphosphoric triamide; and the stabilizer is zinc stearate.

[0111] The active substance in step (2) is 4-methylbenzophenone.

[0112] The power of the ultrasound in step (2) is 400W.

[0113] The drying in step (3) refers to drying at 65° C. for 24 hours.

[0114] An ultraviolet deoxygenation fresh-keeping packaging material prepared by the preparation method as described above.

[0115] The thickness of the ultraviolet deoxygenation fresh-keeping packaging material is 19 microns.

[0116] An application of an ultraviolet deoxygenation fresh-keeping packaging material, wherein the ultraviolet deoxygenation fresh-keeping packaging material is applied to the packaging of articles.

[0117] A method for deoxygenating an ultraviolet deoxygenation fresh-keeping packaging material, the deoxygenation method comprising the following steps:

[0118] The ultraviolet deoxygenation fresh-keeping packaging material is made into a bag, the articles are put into the bag, the bag is sealed, and then the bag is irradiated with ultraviolet light having a wavelength of 365 nm for 45 minutes.

[0119] Comparative Example 1

[0120] Based on Example 6, the alkyl mercaptan in step C was replaced with an equal weight of dimethyl sulfoxide, and the rest remained unchanged.

[0121] Comparative Example 2

[0122] Based on Example 6, the alkyl mercaptan in step C was replaced by an equal weight of component B, and the rest remained unchanged.

[0123] Comparative Example 3

[0124] Based on Example 6, step A and step C are not performed, and the rest remain unchanged.

[0125] Comparative Example 4

[0126] Based on Example 6, the light stabilizer in step (1) was replaced with an equal weight of plastic, and the rest remained unchanged.

[0127] Test Example 1

[0128] Anti-ultraviolet aging test:

[0129] The mixed materials in step (1) of Example 6 and Comparative Examples 1-4 were extruded and naturally cooled to room temperature to obtain sheets with specifications of 120 mm*25 mm*4 mm, and then the tensile strength was tested according to standard GB / T 1040.2-2022 (the tensile speed was 5 mm / min), recorded as A1. At the same time, the above sheet was irradiated under ultraviolet light with a wavelength of 365 nm for 2000 h. After the irradiation, the tensile strength was tested again by the same method, recorded as A2, and the decrease rate of tensile strength can be calculated.

[0130] Table 1. Anti-UV aging test results

[0131] Tensile strength decrease rate / % Example 6 3.3 Comparative Example 1 7.1 Comparative Example 2 5.7 Comparative Example 3 18.6 Comparative Example 4 19.3

[0132] From the comparison between Example 6 and Comparative Examples 1-4 in Test Example 1, it can be seen that the outer layer of the UV deoxygenation fresh-keeping packaging material prepared by the present invention can have a more excellent ability to resist UV aging and degradation.

[0133] against Figure 1 The analysis showed that there was delayed photoluminescence under ultraviolet light, proving the generation of triplet excitons.

[0134] against Figure 2 According to the analysis, after exposure to ultraviolet light, the oxygen content in the bag dropped from 18% to 4%, proving that deoxygenation can be effectively performed.

[0135] against Figure 3 According to the analysis, after irradiation with ultraviolet light, the oxygen content in the bag dropped from 18% to 3.2%, proving that deoxygenation can be effectively performed.

[0136] against Figure 4 According to the analysis, after irradiation with ultraviolet light, the oxygen content in the bag dropped from 18% to 2.9%, proving that deoxygenation can be effectively performed.

[0137] against Figure 5 According to the analysis, after exposure to ultraviolet light, the oxygen content in the bag dropped from 18% to 5.3%, proving that deoxygenation can be effectively performed.

[0138] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for preparing an ultraviolet deoxygenation fresh-keeping packaging material, characterized in that: The preparation method comprises the following steps: (1) mixing the plastic and the light stabilizer at a mass ratio of 98-100:1 at 195-200° C. for 5-10 min, and casting the film into a film with a thickness of 10-15 μm using a casting machine to obtain an outer layer; (2) mixing the dispersant, polyethylene terephthalate, active substance, antioxidant, ultraviolet light absorber and stabilizer in a mass ratio of 100:20:0.2-1.6:0.02-0.1:0.02-0.1:0.02-0.1 under ultrasound at 80-85° C. for 12-14 h to obtain a coating solution; (3) The coating liquid is applied on one side of the outer layer and dried to complete the preparation.

2. The method for preparing a UV deoxygenation fresh-keeping packaging material according to claim 1, characterized in that: The light stabilizer in step (1) is prepared by the following steps: Step A: adding ethylenediamine solution dropwise to trimethylolpropane triacrylate while stirring at 40-50° C., stirring at a constant temperature for 6-8 hours after the addition is completed, and distilling under reduced pressure to obtain component A; the ethylenediamine solution refers to a solution of ethylenediamine and methanol mixed at a mass ratio of 1:8-10 at room temperature; the molar ratio of the trimethylolpropane triacrylate to the ethylenediamine is 1:0.25-0.26; Step B: adding 15-20 parts by weight of methyl thioglycolate, 3-4 parts by weight of pentamethylpiperidinol and 1-2 parts by weight of magnesium methoxide to 100 parts by weight of dimethyl sulfoxide, and then heating under reflux at 70-75° C. for 8-10 hours, purifying, and obtaining component B; Step C: Add 4 parts by weight of component A, 2 parts by weight of component B, 1-1.5 parts by weight of alkyl mercaptan and 0.5 parts by weight of benzoin dimethyl ether to 100 parts by weight of dimethyl sulfoxide, then stir and mix for 1-1.5 hours under ultraviolet light irradiation at 30-35° C., cool to 0-5° C., filter, take the filter residue, wash with deionized water, and finally vacuum dry at 50-70° C. until constant weight, and the preparation is completed.

3. The method for preparing a UV deoxygenation fresh-keeping packaging material according to claim 2, characterized in that: The reduced pressure distillation in step A refers to distillation at 30° C. under a vacuum degree of −0.07 MPa until the volatiles are completely removed.

4. The method for preparing a UV deoxygenation fresh-keeping packaging material according to claim 2, characterized in that: The purification in step B refers to first distilling at 60°C for 30-45min to remove volatiles, then distilling at 125-130°C for 60min to collect the fraction and cool it to room temperature, then adding 25-30 parts by weight of deionized water, filtering, taking the filter residue, washing it with deionized water, and finally vacuum drying it at 40-60°C until constant weight.

5. The method for preparing a UV deoxygenation fresh-keeping packaging material according to claim 2, characterized in that: The alkyl mercaptan in step C is at least one of tetradecanethiol, hexadecanethiol and octadecanethiol.

6. The method for preparing a UV deoxygenation fresh-keeping packaging material according to claim 1, characterized in that: The working parameters of the casting machine in step (1) are as follows: the die head temperature is controlled at 190-200°C, and the cooling roller temperature is controlled at 30-35°C.

7. The method for preparing a UV deoxygenation fresh-keeping packaging material according to claim 1, characterized in that: The dispersant in step (2) is at least one of dimethyl isosorbide, tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide and dimethyl sulfoxide; the antioxidant is at least one of antioxidant 1076, antioxidant 1010 and antioxidant 264; the ultraviolet light absorber is at least one of phenyl o-hydroxybenzoate, resorcinol monobenzoate and hexamethylphosphoric acid triamide; the stabilizer is at least one of zinc stearate, cadmium stearate and lead stearate; the active substance is at least one of benzophenone, benzophenone derivatives and β-diketone derivatives.

8. An ultraviolet deoxygenation fresh-keeping packaging material prepared by the preparation method according to any one of claims 1 to 7.

9. The ultraviolet deoxygenation fresh-keeping packaging material according to claim 8, characterized in that: The thickness of the ultraviolet deoxygenation fresh-keeping packaging material is 18-20 microns.

10. An application of the ultraviolet deoxygenation fresh-keeping packaging material prepared by the preparation method according to any one of claims 1 to 7, characterized in that: The ultraviolet deoxygenation fresh-keeping packaging material is used in the packaging of articles.

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