High-barrier VMBOPP film

Abstract

A high-barrier VMBOPP film comprises a first aluminized layer, a second high-barrier coating, a third heat sealing layer and a fourth BOPP film layer from top to bottom, and the first aluminized layer is made of metal aluminum; the second layer of high-barrier coating is PVA polyvinyl alcohol; the third heat sealing layer is an ethylene-propylene-butylene terpolymer and / or an ethylene-propylene biopolymer; and the fourth BOPP film layer is a biaxially oriented polypropylene film. According to the invention, the BOPP base film with excellent performance is selected, is treated by a special heat sealing process, and is coated with the PVA coating liquid modified by a company, so that the original optical, mechanical and barrier properties of PVA are ensured, and the problem of poor water resistance is solved.

Description

Technical Field

[0001] The invention relates to the technical field of food outer packaging, in particular to a high-barrier VMBOPP film. Background Art

[0002] At present, the common high barrier materials in flexible packaging are PDVC, PVA, and EVOH. The common usage methods are liquid coating and co-extrusion film making. The produced BOPP high barrier film is compounded with a variety of substrates to replace the multi-layer barrier film composite structure, reduce product costs, and improve packaging quality and market competitiveness. It is mainly used in the outer packaging of biscuits, snacks, candies, chocolates, fried nuts and other foods.

[0003] These materials each have different barrier properties and application characteristics: 1. Affected by factors such as BOPP base film performance, processing technology, equipment fine plating, etc., the performance of VMBOPP high barrier film is often not met, such as: barrier properties, heat resistance, water resistance, poor aluminum plating adhesion, etc.

[0004] 2. The use of high barrier liquid for coating and film making also has performance or cost defects, such as: (21) EVOH barrier liquid is easy to absorb moisture, which affects its barrier properties. Therefore, it must usually be used in combination with other materials to prevent water absorption from affecting its barrier properties, which will significantly increase the overall cost.

[0005] (22) PDVC has high gas barrier, oxygen barrier and water barrier properties and excellent moisture resistance, but is limited by environmental protection and safety requirements, and has poor aluminum plating adhesion, so it is gradually being replaced.

[0006] (23) PVA has good transparency and toughness, low permeability to gases and organic chemical reagent vapors, excellent air tightness and fragrance retention. It has excellent stress cracking resistance, chemical resistance and oil resistance. Compared with EVOH and PDVC, it not only has performance advantages, but also has the advantage of lower prices. However, its poor water resistance is the main obstacle to its market promotion. Summary of the invention

[0007] In order to solve the above problems in the prior art, the present invention provides a high barrier VMBOPP film.

[0008] The technical solution adopted by the present invention to solve its technical problem is: A high barrier VMBOPP film comprises, from top to bottom, a first aluminum plating layer, a second high barrier coating layer, a third heat sealing layer and a fourth BOPP film layer, wherein: the first aluminum plating layer is metallic aluminum; the second high barrier coating layer is PVA polyvinyl alcohol; the third heat sealing layer is ethylene-propylene-butene terpolymer and / or ethylene-propylene binary copolymer; the fourth BOPP film layer is a biaxially oriented polypropylene film.

[0009] A preparation process of a high-barrier VMBOPP film, which takes the fourth BOPP film layer of the third heat-sealing layer as a substrate, uses a high-precision special coating machine to evenly coat a second high-barrier coating on the third heat-sealing layer, and after aging for 48 hours and 55°C, uses a vacuum aluminum coating machine to vacuum-plate aluminum on the second high-barrier coating to form a first aluminum coating layer. After testing, a high-barrier VMBOPP film is finally formed after all indicators are qualified.

[0010] The present invention also has the following additional technical features: as a further specific optimization of the technical solution of the present invention: the thickness of the first aluminum plating layer is 0.02-0.06μm; the thickness of the second high barrier coating layer is 0.5-1μm; the thickness of the third heat sealing layer is 0.5-1μm, and the heat sealing strength is above 2N; the thickness of the fourth BOPP film layer is 18-25μm, and the non-thermal heat sealing layer has a dyne of more than 38.

[0011] Compared with the prior art, the present invention has the following advantages: The invention solves the problem of poor adhesion of PVA when directly coating the BOPP base film.

[0012] The invention solves the problem that the aluminum layer has poor adhesion after the BOPP base film is coated with PVA and then aluminum is plated again.

[0013] The present invention selects a BOPP base film with excellent performance, processes it through a special heat-sealing process, and applies the modified PVA coating liquid, thereby ensuring the original optical, mechanical, and barrier properties of PVA and solving the problem of poor water resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the structure of the present invention.

[0015] Figure 2 This is the inspection report of the high barrier VMBOPP film of the present invention.

[0016] Figure 3 This is the product inspection report of the high barrier VMBOPP film of the present invention. DETAILED DESCRIPTION

[0017] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings.

[0018] Embodiment 1 A high barrier VMBOPP film includes, from top to bottom, a first aluminum-plated layer, a second high barrier coating layer, a third heat-sealing layer and a fourth BOPP film layer, wherein: the first aluminum-plated layer is metal aluminum; the second high barrier coating layer is PVA polyvinyl alcohol; the third heat-sealing layer is ethylene-propylene-butene terpolymer and / or ethylene-propylene binary copolymer; the fourth BOPP film layer is a biaxially oriented polypropylene film. The thickness of the first aluminum-plated layer is 0.02-0.06 μm; the thickness of the second high barrier coating layer is 0.5-1 μm; the thickness of the third heat-sealing layer is 0.5-1 μm, and the heat-sealing strength is above 2N; the thickness of the fourth BOPP film layer is 18-25 μm, and the non-thermal heat-sealing strength is above 38 dynes. Example

[0019] A preparation process for a high-barrier VMBOPP film, wherein the thickness of the third heat-sealing layer is 0.5-1μm, the thickness of the fourth BOPP film layer is 18-25μm, and the fourth BOPP film layer of the third heat-sealing layer is used as the substrate, and a high-precision special coating machine is used to evenly coat the second high-barrier coating on the third heat-sealing layer, and the thickness of the second high-barrier coating is 0.5-1μm. After 48H and 55℃ aging, a vacuum aluminum coating machine is used to vacuum-plate aluminum on the second high-barrier coating to form a first aluminum coating layer, and the thickness of the first aluminum coating layer is 0.02-0.06μm. After testing, a high-barrier VMBOPP film is finally formed after all indicators are qualified.

[0020] The present invention significantly improves the barrier properties of VMBOPP film through the combination of specific levels and material selection. In particular, PVA polyvinyl alcohol as a high barrier coating not only maintains its original excellent barrier properties, but also overcomes its disadvantage of poor water resistance through special process treatment, so that the film has good water resistance while maintaining high barrier properties.

[0021] In addition, the VMBOPP film structure of the present invention also ensures the overall strength and stability of the film by optimizing the thickness of each layer. The thickness of the aluminum-plated layer is controlled within the range of 0.02-0.06 μm, which not only ensures the adhesion and barrier effect of the aluminum layer, but also avoids the cost increase and performance degradation caused by excessive thickness. The thickness of the high-barrier coating is controlled within 3-7 μm, which not only meets the barrier performance requirements but also maintains the flexibility of the film. The design of the thickness and heat-sealing strength of the heat-sealing layer ensures the heat-sealing effect and sealing performance of the film during the packaging process.

[0022] In general, the VMBOPP film structure of the present invention solves the problems existing in the prior art through innovative layer design and material selection, improves the comprehensive performance of the film, and provides a new solution for the food outer packaging industry.

[0023] Comparative Example By comparison, it can be seen that the VMBOPP film of the present invention has achieved an ideal barrier effect in terms of oxygen permeability and water vapor permeability, and the aluminum plating adhesion is significantly improved, which is better than other similar products on the market. This improvement not only improves the barrier performance of packaging materials, but also enhances the reliability and durability of packaging, providing a better choice for fields such as food that require high barrier packaging.

[0024] In summary, Example 1, Example 2 and Comparative Example: The present invention has been verified through a large number of experiments. First, the BOPP base film is treated with a special coating and heat-sealing process to improve the adhesion of the PVA film. Secondly, under the premise of ensuring the high barrier performance of PVA, a variety of suitable molecular weight PVA base materials are selected for further processing and cross-linking reaction, so that the surface tension of the film after forming reaches more than 55 (the surface tension of conventional PVA film is within 48), so as to achieve the goal of improving the adhesion of the subsequent aluminum plating layer.

[0025] The present invention further performs a special water-resistant process on the surface of the PVA after film formation, so that its water resistance is effectively improved. After a series of process stability adjustments and deep processing of materials, the present invention finally makes the adhesion, water resistance stability, barrier properties and other indicators of our company's high barrier VMBOPP film reach the domestic leading level.

[0026] The above detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention but merely represents selected embodiments of the present invention.

Claims

1. A high barrier VMBOPP film, characterized in that: From top to bottom, it includes a first aluminum-plated layer, a second high-barrier coating layer, a third heat-sealing layer and a fourth BOPP film layer, wherein: the first aluminum-plated layer is metallic aluminum; the second high-barrier coating layer is PVA polyvinyl alcohol; the third heat-sealing layer is ethylene-propylene-butene terpolymer and / or ethylene-propylene binary copolymer; the fourth BOPP film layer is a biaxially oriented polypropylene film.

2. The high barrier VMBOPP film according to claim 1, characterized in that: The thickness of the first aluminum coating layer is 0.02-0.06μm; the thickness of the second high barrier coating layer is 0.5-1μm; the thickness of the third heat sealing layer is 0.5-1μm, and the heat sealing strength is above 2N; the thickness of the fourth BOPP film layer is 18-25μm, and the non-thermal heat sealing strength is above 38 dynes.

3. A process for preparing a high barrier VMBOPP film, characterized in that: Taking the fourth BOPP film layer of the third heat-sealing layer as the base material, a high-precision special coating machine is used to evenly coat the second high-barrier coating on the third heat-sealing layer. After aging for 48 hours and 55°C, a vacuum aluminum coating machine is used to vacuum-plate aluminum on the second high-barrier coating to form the first aluminum coating layer. After testing, all indicators are qualified and finally a high-barrier VMBOPP film is formed.

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