High-barrier composite material based on vacuum evaporation magnesium layer as well as preparation method and application of high-barrier composite material

Abstract

The invention relates to the field of packaging materials, and discloses a high-barrier composite material based on a vacuum evaporation magnesium layer, the high-barrier composite material comprises a selectable functional layer and a basic functional layer, the selectable functional layer comprises at least one of a protective layer and a heat sealing layer, the basic functional layer comprises a base material layer and a magnesium metal layer, the magnesium metal layer is deposited on the surface of the base material layer through a vacuum evaporation technology, and the magnesium metal layer is deposited on the surface of the base material layer. The optional functional layer is compounded on the surface of the metal magnesium layer. The technical prejudice that magnesium metal is difficult to directly replace aluminum in a packaging material is overcome, and the packaging material which is low in price and capable of actively reducing O2, ethylene and active oxygen in a package, creating a low-oxygen and high-CO2 controlled atmosphere environment, inhibiting fresh food breathing and oxidative aging and remarkably prolonging the refreshing time is obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of packaging materials, in particular to a high-barrier composite material based on vacuum evaporation magnesium layer, a preparation method and applications thereof. BACKGROUND

[0002] In the field of packaging materials, vacuum evaporation aluminum film as a high-performance barrier material is widely used in food, medicine and other packaging fields with high quality requirements, due to its excellent oxygen barrier, moisture barrier, light barrier and heat sealing performance. By heating and evaporating metal aluminum in a high vacuum environment, aluminum vapor is formed and deposited on the surface of a plastic substrate (such as PET, BOPP or PE, etc.) to form an extremely thin and dense aluminum layer, thereby significantly improving the barrier performance of the packaging material, effectively delaying the oxidation, moisture absorption and photolysis process of the contents, and prolonging the shelf life of the contents.

[0003] However, although vacuum evaporation aluminum film has significant advantages in functionality, since aluminum is not an essential trace element for the human body, there are some potential risks when it is used in food or medicine packaging. For example, when the packaging is damaged or the aluminum layer falls off, the aluminum debris may enter the human body with the contents. At the same time, since metal aluminum is an amphoteric metal, it can react with acids and bases. When the contents contain acidic or high-salt foods such as lemon, vinegar, ketchup or salted fish, the aluminum layer is easily corroded, leading to the dissolution of chloride ions. Although the migration of regular packaging usually meets the national standard (such as GB4806.10), the Expert Committee of the World Health Organization (WHO) and the Food and Agriculture Organization (FAO) believes that the intake of trace amounts of aluminum by the human body can be metabolized and excreted by the kidneys, as long as it does not exceed the "weekly tolerable intake" (PTWI), it is safe. However, since aluminum has an accumulative effect, if it is ingested in large amounts for a long time (combined with aluminum-containing food additives such as alum and aluminum cookware), excessive aluminum may accumulate in the body, potentially causing chronic toxicity to the nervous system (such as memory) and the skeletal system. SUMMARY

[0004] The present application aims to provide a high-barrier composite material based on vacuum evaporation magnesium layer, a preparation method and applications thereof, to replace the application of vacuum evaporation aluminum film in food or medicine packaging, thereby reducing the risk of excessive intake of aluminum elements by the human body.

[0005] To achieve the above-mentioned purpose, the present application adopts the following technical solution: a high-barrier composite material based on vacuum evaporation magnesium layer, comprising an optional functional layer and a basic functional layer, the optional functional layer comprising at least one of a protective layer and a heat sealing layer, the basic functional layer comprising a substrate layer and a metal magnesium layer, the metal magnesium layer being deposited on the surface of the substrate layer by vacuum evaporation technology and being mutually compounded with the substrate layer, and the optional functional layer being compounded on the surface of the metal magnesium layer.

[0006] The beneficial effects of the present scheme are: generally speaking, the person skilled in the art believes that, since magnesium metal is a kind of active metal, it is easy to oxidize, and the coating is brittle, it is difficult to directly replace aluminum in packaging materials, the technical scheme of the present application takes magnesium metal as the core layer of the packaging material, and the substrate layer is used to isolate the external environment from the fresh food, and the active chemical properties of magnesium metal are used, on the one hand, low-barrier materials can be selected as optional functional layers, and the oxidation-reduction reaction between the water vapor and oxygen generated by the retention of the fresh food bag and the physiological activity of the fresh food and the magnesium metal can reduce the oxygen concentration in contact with the fresh food, create and maintain a low-oxygen and high-carbon dioxide modified atmosphere environment, so that the respiration of the fresh food is inhibited, at the same time, the hydrogen atoms generated by the oxidation-reduction reaction actively remove ethylene and active oxygen generated by the physiological activity of hydrogen gas, so that the oxidation and aging rate of the fresh food is reduced, and the hydrogen gas escaping activates the stress resistance of the fresh food, so that the shelf life of the fresh food is greatly extended.

[0007] On the other hand, when the food to be packaged is meat and other foods with high barrier requirements for materials, the optional functional layer material with high barrier performance can be combined with the magnesium metal layer, at this time, the metal properties of magnesium metal can be used together with the optional functional layer material to form a firm physical barrier, providing barrier performance for the food in the package, and compared with aluminum, the density of magnesium metal is lower, and the price of magnesium metal is lower than that of aluminum, so that the weight of the packaging material made of magnesium metal is lighter, not only reducing the manufacturing cost, but also reducing the transportation cost.

[0008] Further, the optional functional layer is formed by a heat-sealing layer composite arranged on the surface of the magnesium metal layer. Through the arrangement of the heat-sealing layer, after the packaging is completed, the heat-sealing layer can be directly sealed by a heat press or a sealing machine, which improves the convenience and sealing performance of the packaging.

[0009] Further, the optional functional layer includes an inorganic protective layer, and the inorganic protective layer is formed by one of silicon dioxide (SiO2), aluminum oxide (Al2O3) or magnesium fluoride (MgF2) composite on the surface of the magnesium metal layer. Through the arrangement of the inorganic protective layer, the wear resistance of the side with the inorganic protective layer is greatly improved, which is beneficial to improve the mechanical strength of the material.

[0010] Further, the optional functional layer further includes a heat-sealing layer, and the heat-sealing layer is composite arranged on the surface of the inorganic protective layer.

[0011] Further, the material of the heat-sealing layer is one of cast polypropylene (CPP), polyethylene (PE), polypropylene (PP), ionic polymer or heat-sealing modified polyester (PET-G / APET).

[0012] Furthermore, the substrate layer is made of one of the following materials: polyethylene terephthalate (PET), biaxially oriented polypropylene (BOPP), polyamide (PA), cast polypropylene (CPP), polyethylene (PE), or polylactic acid (PLA).

[0013] Furthermore, the thickness of the magnesium metal layer is less than or equal to 10 μm.

[0014] Furthermore, the preparation method includes the following steps: S1. Pre-treat the substrate to achieve a surface tension of 38-46 dyn / cm; S2. Place the pretreated substrate and magnesium material in a vacuum chamber and evacuate until the base pressure does not exceed 5.0 × 10⁻⁶. - 2 Pa; S3. In a vacuum environment, the magnesium material is heated until it evaporates, and the deposition rate is controlled at 0.01-999nm / s to deposit a metallic magnesium layer on the substrate surface.

[0015] Furthermore, after the formation of the magnesium metal layer, the inorganic protective layer is deposited in situ on the surface of the magnesium layer by plasma-enhanced chemical vapor deposition (PECVD) or evaporation without disrupting the vacuum.

[0016] This solution also protects the application of high-barrier composite materials based on vacuum-deposited magnesium layers in food packaging, pharmaceutical packaging, or electronic component packaging. The high-barrier composite material based on vacuum-deposited magnesium layers includes an optional functional layer and a basic functional layer. The optional functional layer includes at least one of a protective layer and a heat-sealing layer. The basic functional layer includes a substrate layer and a magnesium metal layer. The magnesium metal layer is deposited on the surface of the substrate layer by vacuum evaporation technology and is composited with the substrate layer. The optional functional layer is composited on the surface of the magnesium metal layer. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of an embodiment of the present invention.

[0018] The reference numerals in the accompanying drawings include: substrate layer 1, magnesium metal layer 2, inorganic protective layer 3, and heat-sealing layer 4. Detailed Implementation

[0019] Example The basic implementation examples are as follows: Figure 1 As shown, Figure 1The high-barrier composite material based on vacuum-deposited magnesium layer shown includes an optional functional layer and a basic functional layer. The optional functional layer is at least one of a protective layer and a heat-sealing layer. The protective layer is made of one of silicon dioxide (SiO2), aluminum oxide (Al2O3), or magnesium fluoride (MgF2). The heat-sealing layer is made of one of cast polypropylene (CPP), polyethylene (PE), polypropylene (PP), ionomer, or heat-sealing modified polyester (PET-G / APET).

[0020] The basic functional layer includes a substrate layer and a magnesium metal layer. The substrate layer is made of one of the following materials: polyethylene terephthalate (PET), biaxially oriented polypropylene (BOPP), polyamide (PA), cast polypropylene (CPP), polyethylene (PE), or polylactic acid (PLA).

[0021] The magnesium metal layer is deposited on the surface of the substrate layer using vacuum evaporation technology and is then combined with the substrate layer.

[0022] The preparation method is as follows: S1. Pre-treat the substrate to make its surface tension reach 38-46 dyn / cm; S2. Place the pretreated substrate and magnesium material in a vacuum chamber and evacuate until the base pressure does not exceed 5.0 × 10⁻⁶. - 2 Pa; S3. Under vacuum conditions, the magnesium material is heated until it evaporates, and the deposition rate is controlled between 0.01-999 nm / s to deposit a metallic magnesium layer with a thickness of less than or equal to 10 μm on the substrate surface. In this embodiment, the thickness of the metallic magnesium layer is 1 μm. During evaporation, the evaporation boat is heated to room temperature - 1500°C, the substrate temperature is controlled between room temperature - 300°C, the distance between the evaporation boat and the substrate is controlled between 100-700 mm, the substrate stage rotation is controlled at ≤25 rpm, and the deposition rate is controlled between 0.01 nm / s and 999 nm / s.

[0023] After the magnesium metal composite is completed, the heat-sealing layer is bonded to the magnesium metal layer with adhesive while maintaining the vacuum. The adhesive can be selected from one of the following: polyurethane (PU) adhesive, acrylic ester adhesive, UV curing adhesive, modified acrylic (AB adhesive), acrylic pressure-sensitive adhesive, epoxy resin adhesive, or water-based composite adhesive. After applying the adhesive, the adhesive is rolled using a roller press, and then placed in an oven at 50℃-70℃ for 8-72 hours to complete the curing.

[0024] When in use, the heat-sealing surface faces the contents and is sealed using a heat press or sealing machine.

[0025] Example 2 Example 2 is basically the same as Example 1, except that the optional functional layer is an inorganic protective layer. The inorganic protective layer is disposed between the magnesium metal layer and the heat-sealing layer. Specifically, the inorganic protective layer is formed by composite of one of silicon dioxide (SiO2), aluminum oxide (Al2O3), or magnesium fluoride (MgF2) on the surface of the magnesium metal layer. During preparation, after the formation of the magnesium metal layer, and without disrupting the vacuum, the inorganic protective layer is deposited in situ on the surface of the magnesium layer by plasma-enhanced chemical vapor deposition (PECVD) or evaporation.

[0026] Example 3 Based on Example 1, the optional functional layer also includes an inorganic protective layer. The inorganic protective layer is disposed between the magnesium metal layer and the heat-sealing layer. During preparation, after the magnesium metal layer is formed, and without breaking the vacuum, the inorganic protective layer is deposited in situ on the surface of the magnesium layer by plasma-enhanced chemical vapor deposition (PECVD) or evaporation. After the inorganic protective layer is formed, the heat-sealing layer and the inorganic protective layer are bonded together with adhesive.

[0027] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that the technical means for solving problems in the above embodiments of the present invention can be used in combination to solve multiple technical problems simultaneously. For those skilled in the art, several modifications and improvements can be made without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. High barrier composite based on a vacuum evaporated magnesium layer, characterized in that: The high-barrier composite material comprises an optional functional layer and a basic functional layer, the optional functional layer comprises at least one of a protective layer and a heat-seal layer, and the basic functional layer comprises a substrate layer and a magnesium layer, the magnesium layer is deposited on the surface of the substrate layer by a vacuum evaporation technique and is combined with the substrate layer, and the optional functional layer is combined on the surface of the magnesium layer.

2. High barrier composite based on vacuum-evaporated magnesium layer according to claim 1, characterized in that: The optional functional layer is formed by combining the heat-seal layer on the surface of the magnesium layer.

3. The high barrier composite based on vacuum evaporated magnesium layer according to claim 1, characterized in that: The optional functional layer comprises an inorganic protective layer, the inorganic protective layer is formed by combining one of silicon dioxide (SiO2), aluminum oxide (Al2O3) or magnesium fluoride (MgF2) on the surface of the magnesium layer.

4. High barrier composite based on vacuum-evaporated magnesium layer according to claim 3, characterized in that: The optional functional layer further comprises a heat-seal layer, and the heat-seal layer is combined on the surface of the inorganic protective layer.

5. High barrier composite based on vacuum-evaporated magnesium layers according to claim 2 or 4, characterized in that: The heat-seal layer is made of one of cast polypropylene (CPP), polyethylene (PE), polypropylene (PP), an ionic polymer or a heat-seal modified polyester (PET-G / APET).

6. The high barrier composite based on vacuum evaporated magnesium layer according to claim 1, characterized in that: The substrate layer is made of one of polyethylene terephthalate (PET), biaxially oriented polypropylene (BOPP), polyamide (PA), cast polypropylene (CPP), polyethylene (PE) or polylactic acid (PLA).

7. The high barrier composite based on vacuum evaporated magnesium layer according to claim 1, characterized in that: The thickness of the magnesium layer is less than or equal to 10 μm.

8. High barrier composite based on vacuum-evaporated magnesium layers according to claim 3 or 4, characterized in that: The preparation method of the basic functional layer comprises the following steps: S1, pretreating the substrate to make the surface tension reach 38-46 dyn / cm; S2, the pretreated substrate and magnesium material are placed in a vacuum chamber, vacuumed to a base pressure of not higher than 5.0 x 10 -2 Pa; S3, heating the magnesium material to evaporate under a vacuum environment, controlling the deposition rate to be 0.01-999 nm / s, and depositing the magnesium layer on the surface of the substrate.

9. High barrier composite based on vacuum-evaporated magnesium layers according to claim 8, characterized in that: The combination method of the protective layer is that, after the magnesium layer is formed, the inorganic protective layer is deposited on the surface of the magnesium layer in situ by plasma enhanced chemical vapor deposition (PECVD) or evaporation method without destroying the vacuum.

10. Application of the high-barrier composite material based on the vacuum evaporation magnesium layer in the fields of food packaging, medicine packaging or electronic component packaging according to any one of claims 1-4.

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