High-barrier film easy to tear

Abstract

The invention discloses an easy-to-tear high-barrier film, which belongs to the technical field of film packaging, and comprises a base material layer, a binder and a barrier layer from top to bottom, the barrier layer is prepared from the following raw materials in parts by weight: 70 to 90 parts of ethylene-vinyl alcohol copolymer, 5 to 15 parts of modified hexagonal boron nitride, 5 to 8 parts of plasticizer, 1 to 2 parts of lubricant and 0.05 to 2 parts of antioxidant. The prepared high-barrier film is a barrier layer prepared by taking an ethylene-vinyl alcohol copolymer as a main raw material and adding modified hexagonal boron nitride, a plasticizer, a lubricant and an antioxidant, and then the barrier layer is compounded with a base material layer and a binder, so that the high-barrier film with excellent tensile strength and elongation at break is obtained, meanwhile, the oxygen permeability is obviously reduced, and the service life of the high-barrier film is prolonged. And the film also has a certain antibacterial effect, can be widely applied to the fields of food packaging, medical packaging and the like, and has extremely high application value.

Description

Technical Field

[0001] The invention belongs to the technical field of film packaging, and in particular relates to an easily tearable high-barrier film. Background Art

[0002] Barrier film is a plastic packaging product, usually made through polymerization reaction with ethylene as the masterbatch. Its main function is to isolate gas or liquid to protect the packaged items from the influence of the external environment. It is widely used in the packaging and protection of food, medicine, cosmetics, electronic device packaging and other industries.

[0003] With the diversification of market demand, the rapid development of the soft packaging industry and the continuous improvement of living standards, people's demand for the convenience of use and barrier properties of packaging films has continued to increase. The easy-to-tear packaging film design allows consumers to easily and quickly open the package without the help of tools or laborious tearing, thereby improving the convenience and satisfaction of use. This is especially important for modern consumers who pursue instant gratification and convenience. In the existing film design, consumers can easily and quickly open the package without the help of tools or laborious tearing. Common barrier packaging materials include: 1) Polyvinylidene chloride (PVDC). The barrier performance of PVDC barrier film is several times, dozens of times, or even hundreds of times that of ordinary packaging materials. Food packaged with PVDC coating film has excellent protection for the color, aroma, taste, moisture resistance, etc. of food, and can greatly extend the shelf life of the contents, but its waste will produce C during combustion. 12 , will cause environmental pollution. With the enhancement of environmental awareness and the rise of the green packaging revolution, this type of film will gradually be replaced by other packaging materials with better performance and more environmentally friendly. 2) Nylon film is a general term for a class of amide-based polymers. Compared with other general plastic films (such as PE and PP), nylon film has many advantages such as high oxygen barrier properties, puncture strength and tear strength, high temperature resistance and printing performance. At the same time, compared with barrier materials such as EVOH and PVDC, it has the advantages of cost saving and compliance with environmental protection requirements. However, there are many factors that affect the oxygen barrier properties of nylon film, among which the influence of temperature, relative humidity, degree of stretching, raw materials and crystallinity are particularly prominent. The higher the temperature, the greater the oxygen permeability; while the effect of humidity on oxygen permeability is more complicated, and the effect of humidity on oxygen permeability at room temperature is very limited. The lower the viscosity of nylon, the higher the crystallinity, and the higher the oxygen barrier rate. 3) Aluminized film: Aluminized film has good flexibility and can avoid the problem of significantly reduced barrier performance due to bending and breaking of aluminum knots. In some cases, aluminized film has partially replaced aluminum foil and entered the ranks of barrier flexible packaging materials. However, it has defects such as opacity, microwave penetration blocking, and difficulty in recycling. When the packaging requirements are strict, the barrier performance cannot meet the requirements. Moreover, during high-temperature sterilization or boiling, the aluminum layer is prone to fall off.

[0004] In summary, how to obtain a packaging film with high barrier properties and easy tearability is a technical problem that needs to be solved at present. Summary of the invention

[0005] The object of the present invention is to provide an easily tearable high-barrier film to solve one of the technical problems mentioned in the background technology.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] An easily tearable high barrier film comprises, from top to bottom, a substrate layer, an adhesive, and a barrier layer; the barrier layer comprises the following raw materials in parts by weight: 70-90 parts of ethylene-vinyl alcohol copolymer, 5-15 parts of modified hexagonal boron nitride, 5-8 parts of plasticizer, 1-2 parts of lubricant, and 0.05-2 parts of antioxidant.

[0008] As a further embodiment of the present invention, the modified hexagonal boron nitride is prepared by the following steps:

[0009] Hexagonal boron nitride is added to a Tris-HCl buffer solution, ultrasonically dispersed for 4-4.5 hours, dopamine hydrochloride is added, the pH value is adjusted to 8.5-8.6, stirred at 25-27°C for 8-10 hours, centrifuged, washed, filtered, and dried to obtain modified hexagonal boron nitride. By using dopamine to modify hexagonal boron nitride, not only can some of the oxygen-containing groups on the hexagonal boron nitride be reduced, but also because the polydopamine generated by oxidation self-polymerization on the surface of hexagonal boron nitride contains a large number of active functional groups such as hydroxyl groups and amino groups, it can be coated on the surface of hexagonal boron nitride to improve the interaction with the matrix, which is beneficial to improve the compatibility of the dispersion performance of hexagonal boron nitride in the polymer matrix.

[0010] As a further embodiment of the present invention, the usage ratio of hexagonal boron nitride, Tris-HCl buffer solution and dopamine hydrochloride is 0.25-0.4 g:200 mL:0.4-0.5 g.

[0011] As a further embodiment of the present invention, the plasticizer is one of epoxidized soybean oil, triethyl citrate, tributyl citrate, acetyl triethyl citrate and acetyl tributyl citrate.

[0012] As a further embodiment of the present invention, the lubricant is at least one of paraffin, EBS, polyethylene wax, and magnesium stearate.

[0013] As a further embodiment of the present invention, the antioxidant is at least one of antioxidant 1010, antioxidant 168, and antioxidant 1076.

[0014] As a further solution of the present invention, the substrate layer is one of a polyethylene film, a polyethylene terephthalate film, and a polyvinylidene chloride film.

[0015] As a further embodiment of the present invention, the adhesive is at least one of an acrylic adhesive, a polyurethane adhesive, a silicone adhesive, and an epoxy adhesive.

[0016] As a further solution of the present invention, the high barrier film has a thickness of 80-100 μm.

[0017] As a further embodiment of the present invention, the method for preparing the easily tearable high barrier film comprises the following steps:

[0018] Step 1, weighing ethylene-vinyl alcohol copolymer, modified hexagonal boron nitride, plasticizer, lubricant and antioxidant according to weight, adding them into a twin-screw extruder for melt blending, extrusion and granulation to obtain a barrier masterbatch, and putting the barrier masterbatch into an auxiliary machine to obtain a barrier layer after cooling;

[0019] Step 2: Apply the adhesive to the lower surface of the substrate layer, then bond it to the upper surface of the barrier layer, and then perform transverse stretching and heat setting to obtain a high barrier film.

[0020] Beneficial effects of the present invention:

[0021] The high barrier film prepared by the present invention is a barrier layer prepared by using ethylene-vinyl alcohol copolymer as the main raw material, adding modified hexagonal boron nitride, plasticizer, lubricant and antioxidant, and then compounding it with a substrate layer and an adhesive to obtain a high barrier film with excellent tensile strength and elongation at break, while the oxygen permeability is significantly reduced, and it also has a certain antibacterial effect.

[0022] The present invention uses dopamine to modify the surface of hexagonal boron nitride to obtain modified hexagonal boron nitride, which not only improves the compatibility and dispersibility of hexagonal nitrogen nanosheets and polymers, but also adds hexagonal boron nitride nanosheets to blend, which can further extend the diffusion path of gas molecules, inhibit oxygen diffusion and improve the gas barrier performance of the film, and enhance the mechanical properties and mechanical strength of the barrier film. In addition, the surface of hexagonal boron nitride is covered with polydopamine of a specific structure, which enhances the antibacterial properties of hexagonal boron nitride and further enhances the antibacterial ability of the barrier layer.

[0023] The high barrier film prepared by the present invention has good barrier properties, tearability and antibacterial properties, can be widely used in food packaging, medical packaging and other fields, and has extremely high application value. DETAILED DESCRIPTION

[0024] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in 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] Example 1

[0026] This embodiment provides a modified hexagonal boron nitride, and the preparation steps are as follows:

[0027] 0.25 g of hexagonal boron nitride was added to 200 mL of Tris-HCl buffer solution (150 mmol), ultrasonically dispersed for 4.5 h, 0.4 g of dopamine hydrochloride was added, the pH value was adjusted to 8.5, stirred for reaction at 25 ° C for 8 h, centrifuged and washed 3 times, filtered, and dried to obtain modified hexagonal boron nitride.

[0028] Example 2

[0029] This embodiment provides a modified hexagonal boron nitride, and the preparation steps are as follows:

[0030] 0.4 g of hexagonal boron nitride was added to 200 mL of Tris-HCl buffer solution (150 mmol), ultrasonically dispersed for 4.5 h, 0.5 g of dopamine hydrochloride was added, the pH value was adjusted to 8.5, stirred and reacted at 25° C. for 8 h, centrifuged and washed 3 times, filtered, and dried to obtain modified hexagonal boron nitride.

[0031] Example 3

[0032] This embodiment provides an easily tearable high-barrier film, which includes a substrate layer, an adhesive, and a barrier layer from top to bottom;

[0033] The barrier layer comprises the following raw materials in parts by weight: 70 parts of ethylene-vinyl alcohol copolymer, 5 parts of modified hexagonal boron nitride in Example 1, 5 parts of epoxidized soybean oil, 1 part of paraffin wax, and 0.05 parts of antioxidant 1010.

[0034] The preparation steps are as follows:

[0035] Step 1, weighing ethylene-vinyl alcohol copolymer, modified hexagonal boron nitride in Example 1, epoxidized soybean oil, paraffin and antioxidant 1010 in parts by weight, adding them into a twin-screw extruder for melt blending, extrusion and granulation to obtain a barrier masterbatch, and adding the barrier masterbatch into an auxiliary machine to obtain a barrier layer after cooling;

[0036] Step 2: Apply the adhesive to the lower surface of the substrate layer, then bond it to the upper surface of the barrier layer, and then perform transverse stretching and heat setting to obtain a high barrier film (thickness of 80 μm).

[0037] Example 4

[0038] Compared with Example 3, the only difference is:

[0039] 5 parts of the modified hexagonal boron nitride in Example 1 were replaced with 5 parts of the modified hexagonal boron nitride in Example 2.

[0040] Example 5

[0041] Compared with Example 3, the only difference is:

[0042] Replace 5 parts of the modified hexagonal boron nitride in Example 1 with 10 parts of the modified hexagonal boron nitride in Example 1

[0043] Example 6

[0044] Compared with Example 3, the only difference is:

[0045] 5 parts of the modified hexagonal boron nitride in Example 1 were replaced with 15 parts of the modified hexagonal boron nitride in Example 1.

[0046] Example 7

[0047] Compared with Example 3, the only difference is:

[0048] The barrier layer comprises the following raw materials in parts by weight: 80 parts of ethylene-vinyl alcohol copolymer, 8 parts of modified hexagonal boron nitride in Example 1, 6 parts of epoxidized soybean oil, 1.5 parts of paraffin wax, and 1 part of antioxidant 1010.

[0049] Example 8

[0050] Compared with Example 3, the only difference is:

[0051] The barrier layer comprises the following raw materials in parts by weight: 90 parts of ethylene-vinyl alcohol copolymer, 13 parts of modified hexagonal boron nitride in Example 1, 7.5 parts of epoxidized soybean oil, 1.5 parts of paraffin wax, and 1.85 parts of antioxidant 1010.

[0052] Comparative Example 1

[0053] Compared with Example 3, the only difference is:

[0054] The barrier layer comprises the following raw materials in parts by weight: 70 parts of ethylene-vinyl alcohol copolymer, 5 parts of epoxidized soybean oil, 1 part of paraffin wax, and 0.05 parts of antioxidant 1010.

[0055] Comparative Example 2

[0056] Compared with Example 3, the only difference is:

[0057] The barrier layer comprises the following raw materials in parts by weight: 70 parts of ethylene-vinyl alcohol copolymer, 5 parts of hexagonal boron nitride, 5 parts of epoxidized soybean oil, 1 part of paraffin wax, and 0.05 parts of antioxidant 1010.

[0058] Comparative Example 3

[0059] Compared with Example 3, the only difference is:

[0060] Five parts of the modified hexagonal boron nitride in Example 1 were replaced with two parts of the modified hexagonal boron nitride in Example 2.

[0061] Comparative Example 4

[0062] Compared with Example 3, the only difference is:

[0063] 5 parts of the modified hexagonal boron nitride in Example 1 were replaced with 18 parts of the modified hexagonal boron nitride in Example 2.

[0064] Comparative Example 5

[0065] Compared with Example 3, the only difference is:

[0066] The barrier layer comprises the following raw materials in parts by weight: 60 parts of ethylene-vinyl alcohol copolymer, 5 parts of modified hexagonal boron nitride in Example 1, 5 parts of epoxidized soybean oil, 1 part of paraffin wax, and 0.05 parts of antioxidant 1010.

[0067] Comparative Example 6

[0068] Compared with Example 3, the only difference is:

[0069] The barrier layer comprises the following raw materials in parts by weight: 60 parts of ethylene-vinyl alcohol copolymer, 2 parts of modified hexagonal boron nitride in Example 1, 4 parts of epoxidized soybean oil, 1 part of paraffin wax, and 0.05 parts of antioxidant 1010.

[0070] The high barrier films obtained in Examples 3 to 8 and Comparative Examples 1 to 6 were subjected to the following performance tests:

[0071] 1) Tensile strength and elongation at break: According to GB / T 10801-2006 standard, (23±2)℃, (50±5)%RH, electronic universal material testing machine Z1.0, tensile speed 100mm / min;

[0072] 2) Oxygen permeability: According to ASTM D3985-2017 standard, oxygen permeability meter C230, 23°C, 75% RH;

[0073] 3) Antibacterial rate: The antibacterial performance test was carried out according to GB / T 37206-2018 standard.

[0074] The above test results are shown in Table 1:

[0075] Table 1

[0076]

[0077]

[0078] It can be seen from Table 1 that, compared with Comparative Examples 1-6, the high barrier films prepared in Examples 3-8 have good barrier properties, tearability and antibacterial properties, can be widely used in food packaging, medical packaging and other fields, and have extremely high application value.

[0079] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0080] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An easily tearable high barrier film, characterized in that: From top to bottom, it includes a substrate layer, an adhesive, and a barrier layer; the barrier layer includes the following raw materials in parts by weight: 70-90 parts of ethylene-vinyl alcohol copolymer, 5-15 parts of modified hexagonal boron nitride, 5-8 parts of plasticizer, 1-2 parts of lubricant, and 0.05-2 parts of antioxidant.

2. The easily tearable high barrier film according to claim 1, characterized in that: The modified hexagonal boron nitride is prepared by the following steps: The hexagonal boron nitride is added to a Tris-HCl buffer solution, ultrasonically dispersed for 4-4.5 hours, dopamine hydrochloride is added, the pH value is adjusted to 8.5-8.6, stirred for reaction at 25-27° C. for 8-10 hours, centrifuged, washed, filtered, and dried to obtain the modified hexagonal boron nitride.

3. The easily tearable high barrier film according to claim 2, characterized in that: The dosage ratio of hexagonal boron nitride, Tris-HCl buffer solution and dopamine hydrochloride is 0.25-0.4 g: 200 mL: 0.4-0.5 g.

4. The easily tearable high barrier film according to claim 1, characterized in that: The plasticizer is one of epoxidized soybean oil, triethyl citrate, tributyl citrate, acetyl triethyl citrate and acetyl tributyl citrate.

5. The easily tearable high barrier film according to claim 1, characterized in that: The lubricant is at least one of paraffin, EBS, polyethylene wax and magnesium stearate.

6. The easily tearable high barrier film according to claim 1, characterized in that: The antioxidant is at least one of antioxidant 1010 , antioxidant 168 , and antioxidant 1076 .

7. The easily tearable high barrier film according to claim 1, characterized in that: The substrate layer is one of a polyethylene film, a polyethylene terephthalate film and a polyvinylidene chloride film.

8. The easily tearable high barrier film according to claim 1, characterized in that: The adhesive is at least one of acrylic adhesive, polyurethane adhesive, silicone adhesive and epoxy adhesive.

9. The easily tearable high barrier film according to claim 1, characterized in that: The high barrier film has a thickness of 80-100 μm.

10. The easily tearable high barrier film according to claim 1, characterized in that: The method for preparing the easily tearable high-barrier film comprises the following steps: Step 1, weighing ethylene-vinyl alcohol copolymer, modified hexagonal boron nitride, plasticizer, lubricant and antioxidant according to weight, adding them into a twin-screw extruder for melt blending, extrusion and granulation to obtain a barrier masterbatch, and putting the barrier masterbatch into an auxiliary machine to obtain a barrier layer after cooling; Step 2: Apply the adhesive to the lower surface of the substrate layer, then bond it to the upper surface of the barrier layer, and then perform transverse stretching and heat setting to obtain a high barrier film.

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