Barrier film with oxygen barrier effect and water vapor barrier effect and packaging material

Abstract

The invention belongs to the field of packaging materials, and particularly relates to a barrier film with oxygen barrier and water vapor barrier effects, the barrier film comprises an oxygen barrier layer and an oxygen uptake layer which are arranged adjacently, and the oxygen uptake layer comprises an oxygen uptake agent and an oxygen barrier agent. The invention also relates to a packaging material. The barrier film can effectively block oxygen and water vapor.

Description

Technical Field

[0001] The present invention belongs to the field of packaging materials, and in particular relates to a barrier film with oxygen barrier and water vapor barrier effects, and a packaging material comprising the barrier film. Background Art

[0002] The use of physical or chemical vapor deposition transparent coating (PVD / CVD), such as aluminum oxide, silicon oxide, etc., can effectively improve the barrier properties of film materials, but this process has high requirements for the surface polarity and heat resistance of the base film, and the base film used is generally PET, PA, etc. This process is difficult to obtain a high oxygen barrier rate and water vapor barrier rate on a polyolefin base film.

[0003] When using barrier resins such as ethylene-vinyl alcohol copolymer (EVOH), if a higher oxygen barrier effect is to be achieved, the barrier layer must be thicker, which is costly. Moreover, this type of material is only effective in blocking oxygen, but not in blocking water vapor.

[0004] Therefore, there is an urgent need for a film that has both high oxygen barrier effect and water vapor barrier effect. Summary of the invention

[0005] One object of the present invention is to provide a barrier film which can effectively block oxygen and water vapor. Another object of the present invention is to provide a packaging material.

[0006] In order to achieve the above object, the present invention provides a barrier film, comprising an oxygen barrier layer and an oxygen absorbing layer arranged adjacent to each other, wherein the oxygen absorbing layer comprises an oxygen absorber and an oxygen barrier agent.

[0007] Another aspect of the present invention provides a barrier film capable of blocking oxygen and water vapor, comprising an oxygen barrier layer and an oxygen absorbing layer disposed adjacent to each other, wherein the oxygen absorbing layer comprises an oxygen absorbent and an oxygen barrier.

[0008] In any embodiment of the present invention, the oxygen absorber is selected from one or more of cobalt salts, polybutadiene, and ethylene-propylene copolymers, and the oxygen barrier is selected from one or more of montmorillonite, hydrotalcite, graphene, barrier function masterbatch, and wollastonite fiber, preferably a barrier function masterbatch; and / or,

[0009] The oxygen barrier layer includes one or more of ethylene-vinyl alcohol copolymer, polyvinyl alcohol, and nylon.

[0010] In any embodiment of the present invention, in the oxygen absorbing layer, the weight ratio of the oxygen absorber to the oxygen barrier is 1:5-20:1, preferably 1:5-10:1, for example 1:4, 1:3, 1:2, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1.

[0011] In any embodiment of the present invention, the oxygen barrier is a sheet-like structure;

[0012] Optionally, the average thickness of the sheet-like structure is greater than 0 and less than 10 nm.

[0013] In any embodiment of the present invention, the total weight of the oxygen absorber and the oxygen barrier agent in the oxygen absorption layer accounts for 4%-15%, preferably 5%-15%, for example, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%.

[0014] In any embodiment of the present invention, the average thickness of the oxygen absorbing layer is 3-20 μm, preferably 5-20 μm, for example 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm.

[0015] In any embodiment of the present invention, the barrier film comprises an oxygen barrier layer and an oxygen absorption layer disposed adjacent to each other; or,

[0016] The barrier film comprises n+1 oxygen barrier layers and n oxygen absorption layers, where n is 1, 2 or 3, and the oxygen barrier layers and the oxygen absorption layers are arranged at intervals.

[0017] Without being bound by theory: when used in an environment with different internal and external oxygen partial pressures, the barrier film includes an adjacent oxygen barrier layer and an oxygen absorbing layer, wherein the oxygen barrier layer is suitable for blocking oxygen in an environment with higher oxygen partial pressure, and the oxygen absorbing layer is suitable for blocking oxygen in an environment with lower oxygen partial pressure; when used in an environment with the same internal and external oxygen partial pressure, the barrier film preferably includes two oxygen barrier layers and one oxygen absorbing layer, and the oxygen barrier layer and the oxygen absorbing layer are arranged at intervals.

[0018] In any embodiment of the present invention, the barrier film comprises one or more of the following:

[0019] 1) The cobalt salt is selected from one or more of cobalt stearate, cobalt decanoate, and cobalt neodecanoate;

[0020] 2) The weight average molecular weight of the polybutadiene is 1000-5000;

[0021] 3) The weight average molecular weight of the ethylene-propylene copolymer is 5000-50000, the molecular weight distribution coefficient is 1.5-2.5, and the molar content of ethylene is 15-50%;

[0022] 4) The barrier function masterbatch is selected from one or more of Gastop barrier function masterbatch of Ampacet Company and P-802 barrier function masterbatch of Nanocor Company;

[0023] 5) The weight average molecular weight of the ethylene-vinyl alcohol copolymer is 10,000-50,000, the molecular weight distribution coefficient is 1.5-2.5, and the molar content of ethylene is 15%-50%;

[0024] 6) the ethylene-vinyl alcohol copolymer is a block copolymer;

[0025] 7) The oxygen absorbing layer further comprises polyethylene;

[0026] 8) The average thickness ratio of the oxygen barrier layer to the oxygen absorption layer is 1:10-10:1, for example, 1:9, 1:8, 1:7, 1:5, 1:4, 1:2, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1.

[0027] In any embodiment of the present invention, the barrier film further comprises a substrate layer, which is disposed on a side of one or two outermost oxygen barrier layers away from the oxygen absorbing layer.

[0028] In any embodiment of the present invention, the barrier film further comprises an adhesive layer disposed between adjacent oxygen barrier layers and oxygen absorption layers and / or between adjacent substrate layers and oxygen barrier layers.

[0029] In any embodiment of the present invention, the barrier film further includes a color layer and / or an auxiliary material layer with other functions, which can be arranged between the adjacent oxygen barrier layer and the oxygen absorption layer, and / or between the adjacent base layer and the oxygen barrier layer. Optionally, the color layer and the auxiliary material layer with other functions are arranged adjacent to the bonding layer. Here, "other functions" can be functions that have auxiliary effects on oxygen absorption, oxygen barrier, water vapor barrier, bonding, coloring, etc., or can be functions other than oxygen absorption, oxygen barrier, water vapor barrier, bonding, and coloring.

[0030] In any embodiment of the present invention, the barrier film comprises one or more of the following:

[0031] A. the base layer comprises polyethylene;

[0032] B. the bonding layer comprises one or more of ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, and maleic anhydride grafted polyethylene;

[0033] C. The average thickness of the barrier film is 25-80 μm, for example, 28 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm.

[0034] In any embodiment of the present invention, the polyethylene is independently selected from one or both of high-density polyethylene and low-density polyethylene.

[0035] In any embodiment of the present invention, the weight average molecular weight of the polyethylene is independently 200,000-1,500,000, and the molecular weight distribution coefficient of the polyethylene is independently 1.5-2.5.

[0036] In any embodiment of the present invention, the weight average molecular weight of the polyvinyl alcohol is 30,000-60,000.

[0037] In any embodiment of the present invention, the weight average molecular weight of nylon is 10,000-50,000, and the molecular weight distribution coefficient is 1.5-2.5.

[0038] In any embodiment of the present invention, the weight average molecular weight of the ethylene-acrylic acid copolymer is 20,000-50,000, the molecular weight distribution coefficient is 1.5-2.5, and the molar content of ethylene is 85-98%.

[0039] In any embodiment of the present invention, the weight average molecular weight of the ethylene-methacrylic acid copolymer is 10,000-50,000, the molecular weight distribution coefficient is 1.5-2.5, and the molar content of ethylene is 80-95%.

[0040] In any embodiment of the present invention, the weight average molecular weight of the maleic anhydride grafted polyethylene is 20,000-2,000,000, the molecular weight distribution coefficient is 1.5-2.5, and the grafting rate of maleic anhydride is 0.1-2%.

[0041] Yet another aspect of the present invention provides a packaging material comprising the barrier film according to the previous aspect of the present invention.

[0042] Beneficial effects achieved by the present invention:

[0043] The barrier film of the present invention has a high oxygen barrier effect and a high water vapor barrier effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein:

[0045] Figure 1 This is a schematic diagram of the structure of the barrier film of Example 1 of the present invention;

[0046] 1- oxygen barrier layer, 2- oxygen absorption layer, 3- oxygen absorber, 4- oxygen barrier agent, 5- base layer, 6- bonding layer. DETAILED DESCRIPTION

[0047] The embodiments of the present invention will be described clearly and completely below in conjunction with the examples. Obviously, the described examples are only some examples of the present invention, rather than all examples. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the examples in the present invention, all other examples obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0048] Example 1

[0049] Preparation of the barrier film of this embodiment:

[0050] Using a multi-layer film blowing equipment, the materials of each layer are fed into the corresponding feeding port of the equipment, extruded and blown at the screw process temperature to obtain a barrier film. The materials, process temperatures and parameters of each layer are shown in Table 1. Among them, the screw process is divided into 5 temperature zones, and their temperatures are shown in Table 1.

[0051] Table 1 Materials, parameters and process conditions of each layer in the barrier film

[0052]

[0053]

[0054] The parameters of Examples 2-13 and Comparative Examples 1-2 are different from those of Example 1. The different parameters are detailed in Table 2. The rest are the same as Example 1.

[0055] The parameters such as molecular weight, molecular weight distribution coefficient, grafting rate, etc. of the polymers used in all the embodiments and comparative examples are within the aforementioned ranges of the present invention.

[0056]

[0057]

[0058]

[0059] Test method:

[0060] 1. Thickness test of sheet oxygen barrier agent:

[0061] The sheet-like oxygen barrier agent is cut in a direction perpendicular to its surface, the cross section is scanned by a transmission electron microscope, and the thickness is measured at 3-4 positions along the axial direction of the cross section to obtain the average value.

[0062] 2. Average thickness test of each layer:

[0063] The barrier film is cut in a direction perpendicular to its surface, and the cross section is detected by a scanning electron microscope. Since different materials show different contrasts, different layers on the cross section can be distinguished by a scanning electron microscope. The thickness of different layers is measured at an average of 8-10 positions along the length of the cross section, and the average value is taken to obtain the average thickness of each layer.

[0064] 3. D50 test:

[0065] Laser particle size analyzer is used to test D50. D50 refers to the particle size corresponding to when the cumulative particle size distribution percentage of the sample reaches 50%. Its physical meaning is that particles with a particle size larger than it account for 50%, and particles with a particle size smaller than it also account for 50%. D50 is also called the median diameter or median particle size.

[0066] 4. Oxygen permeability test:

[0067] The oxygen permeability of the barrier film is tested by professionals in accordance with GB / T 19789-2021 "Oxygen permeability test of plastic film and sheet for packaging materials - Coulometer test method".

[0068] 5. Water vapor transmission rate test:

[0069] The water vapor transmission rate is tested by professionals using Mocon water vapor barrier test equipment (model 3-34) in accordance with GB / T 26253-2010 "Determination of water vapor transmission rate of plastic film and sheeting - Infrared detector method".

[0070] The results are shown in Table 3.

[0071] Table 3 Results of oxygen permeability and water vapor permeability

[0072]

[0073]

[0074] From Table 3, we can see that:

[0075] Compared with comparative examples 1-2 using only an oxygen absorber or only an oxygen barrier agent, the oxygen barrier property and water vapor barrier property of the barrier film of the present invention are significantly higher;

[0076] Compared with Example 9 which uses a larger amount of oxygen absorbent, the oxygen barrier properties and water vapor barrier properties of the barrier films of Examples 1-5 of the present invention are significantly improved;

[0077] Compared with the oxygen barrier agents in other shapes used in Examples 10-11, the oxygen barrier property and water vapor barrier property of the barrier film in Example 1 of the present invention are significantly improved;

[0078] Compared with Example 12 in which the total weight of the oxygen absorber and the oxygen barrier agent in the oxygen absorbing layer accounts for a relatively small proportion, the oxygen barrier properties of the barrier films of Examples 1-5 of the present invention are significantly improved;

[0079] Compared with Example 13 which uses a thinner oxygen absorbing layer, the oxygen barrier property and water vapor barrier property of the barrier film of Example 1 of the present invention are significantly improved.

[0080] Therefore, the barrier film of the present invention has a very significant barrier effect on oxygen and water vapor.

[0081] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A barrier film comprising an oxygen barrier layer and an oxygen absorbing layer arranged adjacent to each other, wherein the oxygen absorbing layer comprises an oxygen absorbent and an oxygen barrier.

2. A barrier film having oxygen barrier and water vapor barrier effects, comprising an oxygen barrier layer and an oxygen absorbing layer arranged adjacent to each other, wherein the oxygen absorbing layer comprises an oxygen absorber and an oxygen barrier agent.

3. The barrier film according to claim 1 or 2, in, The oxygen absorbent is selected from one or more of cobalt salts, polybutadiene, and ethylene-propylene copolymers; the oxygen barrier is selected from one or more of montmorillonite, hydrotalcite, graphene, barrier functional masterbatch, and wollastonite fiber; and / or, The oxygen barrier layer includes one or more of ethylene-vinyl alcohol copolymer, polyvinyl alcohol, and nylon.

4. The barrier film according to any one of claims 1 to 3, in, In the oxygen absorbing layer, the weight ratio of the oxygen absorber to the oxygen barrier is 1:5-20:1, preferably 1:5-10:

1.

5. The barrier film according to any one of claims 1 to 4, in, The oxygen barrier agent is a sheet-like structure; Optionally, the average thickness of the lamellar structure is less than 10 nm.

6. The barrier film according to any one of claims 1 to 5, in, The total weight of the oxygen absorber and the oxygen barrier agent accounts for 4%-15% of the weight of the oxygen absorbing layer, preferably 5%-15%.

7. The barrier film according to any one of claims 1 to 6, in, The average thickness of the oxygen absorbing layer is 3-20 μm, preferably 5-20 μm.

8. The barrier film according to any one of claims 1 to 7, in, The barrier film comprises an oxygen barrier layer and an oxygen absorption layer arranged adjacent to each other; or, The barrier film comprises n+1 oxygen barrier layers and n oxygen absorption layers, n is 1, 2 or 3, and the oxygen barrier layers and the oxygen absorption layers are arranged at intervals.

9. The barrier film according to any one of claims 1 to 8, Features One or more of the following: 1) The cobalt salt is selected from one or more of cobalt stearate, cobalt decanoate, and cobalt neodecanoate; 2) The weight average molecular weight of the polybutadiene is 1000-5000; 3) The weight average molecular weight of the ethylene-propylene copolymer is 5000-50000, the molecular weight distribution coefficient is 1.5-2.5, and the molar content of ethylene is 15-50%; 4) The barrier function masterbatch is selected from one or more of Gastop barrier function masterbatch of Ampacet Company and P802 barrier function masterbatch of Nanocor Company; 5) The weight average molecular weight of the ethylene-vinyl alcohol copolymer is 10,000-50,000, the molecular weight distribution coefficient is 1.5-2.5, and the molar content of ethylene is 15%-50%; 6) The oxygen absorbing layer further comprises polyethylene; 7) The average thickness ratio of the oxygen barrier layer to the oxygen absorption layer is 1:10-10:

1.

10. The barrier film according to any one of claims 1 to 9, in, The barrier film further comprises a base layer, which is arranged on a side of one or two outermost oxygen barrier layers away from the oxygen absorbing layer, and optionally, the base layer comprises polyethylene; and / or, The barrier film also includes an adhesive layer, which is arranged between adjacent oxygen barrier layers and oxygen absorption layers and / or between adjacent substrate layers and oxygen barrier layers. Optionally, the adhesive layer includes one or more of ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, and maleic anhydride grafted polyethylene.

11. A packaging material comprising the barrier film according to any one of claims 1 to 10.

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