Flexographic printing anti-counterfeiting high-activity dry yeast packaging composite film and preparation method thereof

Abstract

The invention discloses a flexographic printing anti-counterfeiting high-activity dry yeast packaging composite film and a preparation method thereof, the composite film is a composite film with a three-layer structure, the outer part is a printing layer, the middle part is a barrier layer, the inner part is a heat sealing layer, ultraviolet light explicit and implicit ink is printed on the film, and the layers are compounded by adopting an adhesive. The printing layer is a double-corona biaxially oriented polypropylene or biaxially oriented polyethylene glycol terephthalate film base material, the middle barrier layer is an aluminum foil or aluminized polyethylene glycol terephthalate film, and the inner printing layer is an antistatic PE film; a double-component polyurethane solvent-free adhesive is adopted between the layers to form a composite film. The flexographic printing mode is adopted, the height line number needed by anti-fake printing is achieved, the randomly-arranged pattern sequence is adopted, the forgery possibility is greatly reduced, due to the addition of the anti-reflection master batch, the film has higher transparency, and the definition of anti-fake printing is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of packaging, and in particular relates to a flexographic printing anti-counterfeiting high-activity dry yeast packaging composite film and a preparation method thereof. Background Art

[0002] Yeast (saccharomyces) is a single-cell fungus, an edible, nutritious single-cell microorganism. Yeast plays an important role in people's daily lives. In people's lives today, yeast is made into products in solid form and sold as active yeast cell products. We call this product active dry yeast. This product is easy to use and transport, and because of its low water content, it rehydrates quickly. After rehydration and activation under certain conditions, it returns to its natural state and has normal yeast activity. It is very popular because it can be stored at room temperature for a long time in life. Highly active dry yeast is widely used in the fields of fermented pasta processing, brewing, and medicine.

[0003] At present, in addition to requiring a high-barrier composite film to provide a long shelf life for highly active dry yeast, the aluminum-plastic composite film can provide high-active dry yeast with good barrier properties (blocking oxygen and water vapor), which is beneficial to the packaging and preservation of yeast. At the same time, the increasingly rampant existence of counterfeit and inferior products in the market will seriously damage the brand image, reduce consumers' trust in the brand, and further affect the brand's market share and long-term development. In view of this, the present invention proposes a flexographic printing anti-counterfeiting yeast packaging composite film and a preparation method thereof. Summary of the invention

[0004] In order to solve the above problems, the present invention aims to provide a flexographic printing anti-counterfeiting high-activity dry yeast packaging composite film and a preparation method thereof.

[0005] The technical solution of the present invention is as follows: A flexographic printing anti-counterfeiting high-activity dry yeast packaging composite film, the composite film is a composite film with a three-layer structure, wherein the outer layer is a printing layer, the middle layer is a barrier layer, and the inner layer is a heat-sealing layer. Ultraviolet invisible ink is printed on the film, and adhesives are used to compound the layers.

[0006] Preferably, the printing layer is a transparent biaxially stretched polypropylene or transparent biaxially stretched polyethylene terephthalate film substrate, with double-sided corona; the middle barrier layer is aluminum foil or aluminized polyethylene terephthalate film; the inner printing layer is an antistatic PE film. A two-component polyurethane solvent-free adhesive is used between the layers to form a composite film.

[0007] Preferably, the printing method is flexographic printing.

[0008] A method for preparing a flexographic printing anti-counterfeiting high-activity dry yeast packaging composite film, the preparation method comprising the following steps: S1. Put polyethylene terephthalate pellets or polypropylene pellets into the barrel of an extruder, add 3-5 parts of anti-reflection masterbatch, melt-extrude and then perform biaxial stretching to obtain a biaxially stretched polyethylene terephthalate film (BOPET) or a biaxially stretched polypropylene film (BOPP), and perform corona treatment on both sides of the obtained film; S2, using vacuum aluminum plating technology, under vacuum conditions, evaporating an AlOx layer to obtain a longitudinally stretched polyethylene AlOx-PE film; S3, using laser plate making to obtain the corresponding anti-counterfeiting printing flexographic printing plate, transferring the anti-counterfeiting special ink to the printing layer film through flexographic printing, with bright patterns printed on the front and dark patterns printed on the back; S4, using a longitudinally stretched polyethylene AlOx-PE film obtained by vacuum aluminum plating as a barrier layer; S5, using polyethylene synthesized by a metallocene catalyst gas phase method as a raw material, adding an antistatic agent, and using a three-layer co-extrusion blow molding process to process it into a heat-sealing layer film; S6, bonding the printed layer, the barrier layer and the heat-sealing layer by using an adhesive to obtain a composite film; S7, placing the composite film in a curing chamber for curing, and cutting it after cooling to obtain a finished composite film roll.

[0009] Preferably, in step S1, 3-5 parts of anti-reflection masterbatch are added to the printed film.

[0010] Preferably, in step S1, the obtained printed film is corona-treated on both sides, and the dyne value of the biaxially oriented polyethylene terephthalate film (BOPET) is not less than 50, and the dyne value of the biaxially oriented polypropylene film (BOPP) is not less than 38.

[0011] Preferably, in step S2, the film substrate used for vacuum AlOx deposition is a linear low-density PE film, on which a 8-10 nm AlOx layer is evaporated; the vacuum aluminum deposition conditions are 5*10 -2 Pa.

[0012] Preferably, in step S2, the rubber flexographic printing plate is made by laser plate making, the circumference of the printing plate is 450-550 mm, the screen line count is 130-135 LDI, and the thickness is 1.35-1.45 mm; the screen line count of the anilox roller is 350-450 L / cm.

[0013] Further preferably, in step S3, the rubber flexographic printing plate is made by laser plate making, the circumference of the printing plate is 500 mm, the screen line count is 133 LDI, and the thickness is 1.44 mm; the screen line count of the anilox roller is 400 L / cm.

[0014] Preferably, in step S3, the anti-counterfeiting print is composed of a front bright pattern and six types of back dark patterns; The order of anti-counterfeiting stamps is randomly generated; The anti-counterfeiting printing adopts Solimax special anti-counterfeiting ink.

[0015] Preferably, in step S3, the anti-counterfeiting front bright pattern is surface printing, and the back dark pattern is inner printing.

[0016] Preferably, in step S3, the printing method is flexographic printing. When performing flexographic printing, the positions of the plate rollers are specifically arranged to separate the anti-counterfeiting printing roller from the large-format background color.

[0017] Preferably, in step S4, the outer layer and the middle layer are made of linear low-density PE with a melt index of 1.0-2.0 g / 10min and a density of 0.8-0.9 g / cm 3 The inner layer is made of polyethylene synthesized by metallocene catalyst gas phase method, and 1-3 parts of antistatic agent are added, wherein the metallocene melt index is 1.0-2.0 g / 10min, the density is 0.85-0.9g / cm 3 ; In step S5, the adhesive is a two-component polyurethane solvent-free adhesive; In step S5, the layers are compounded without solvent; In step S6, each composite layer needs to be cured separately.

[0018] Compared with the prior art, the present invention has the following beneficial effects: The flexographic printing method is used to achieve the high line count required for anti-counterfeiting printing, and the random arrangement of the pattern sequence greatly reduces the possibility of counterfeiting. The addition of the anti-transparency masterbatch makes the film more transparent and increases the clarity of the anti-counterfeiting printing. At the same time, the different printing methods of the front bright pattern and the back dark pattern ensure the reliability of the anti-counterfeiting printing, and the double-sided corona film makes the printing more reliable. The barrier layer is a longitudinally stretched polyethylene AlOx-PE film, which avoids the problem that the aluminum-plastic composite packaging is not conducive to environmental protection after use, contains "aluminum" pollution, and cannot be recycled and reused. The composite film has anti-counterfeiting function and excellent barrier properties, meeting the requirements of yeast packaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1The present invention provides a structural schematic diagram of a flexographically printed anti-counterfeiting highly active dry yeast packaging composite film and a preparation method thereof, wherein 1 is a biaxially oriented polyethylene terephthalate film (BOPET) or a biaxially oriented polypropylene film (BOPP), 2 is an aluminized polyethylene terephthalate film (VMPET) or an alumina-plated polyethylene terephthalate film (AlOx-PE), and 3 is an antistatic PE.

[0020] Figure 2 This is a schematic diagram of the anti-counterfeiting printing design, which consists of bright patterns on the front and dark patterns on the back, including but not limited to this arrangement.

[0021] Figure 3 The present invention is a flow chart of an embodiment of a preparation method of a flexographic printing anti-counterfeiting highly active dry yeast packaging composite film and a preparation method thereof. DETAILED DESCRIPTION

[0022] The following will be combined with the specific embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. The embodiments described 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 making creative work belong to the protection scope of the present invention.

[0023] Example 1 A flexographic printing anti-counterfeiting high-activity dry yeast packaging composite film and a preparation method thereof, wherein the specific material structure is BOPET12 / VMPET18 / PE40.

[0024] The preparation method is as follows: 1) Preparation of the printing layer: 100 parts of polyethylene terephthalate pellets were placed into the barrel of an extruder, and 3 parts of an anti-reflection masterbatch (model BRUGGOLEN P250, manufacturer Brüggemann) were added. After melt extrusion, biaxial stretching was performed, and the film thickness was controlled to be 12 μm to obtain a biaxially stretched polyethylene terephthalate film (BOPET). The obtained biaxially stretched polyethylene terephthalate film (BOPET) was subjected to double-sided corona treatment, and the corona treatment conditions were a high-frequency voltage of 1000 V / m2, a film temperature of 45°C, and a dyne value of not less than 50; The conditions for biaxial stretching after melt extrusion are: temperature 290°C, stretching ratio 3.0x3.0, 2) Follow Figure 1 The anti-counterfeiting print is made into a printing plate by laser plate making, and the anti-counterfeiting ink is transferred to the printing layer by flexographic printing.

[0025] 3) Preparation of barrier layer: Aluminum film was evaporated on the surface of linear low-density polyethylene film by vacuum evaporation method. A BOBST K5 EXPERT vacuum coating machine was used to evaporate an AlOx layer with a thickness of 8 nm on the surface of the film to obtain an aluminum oxide film (AlOx-PE).

[0026] 4) Preparation of heat-sealing layer: The outer layer and the middle layer are made of linear low-density PE with a melt index of 1.5 g / 10min and a density of 0.85 g / cm3; the inner layer is made of polyethylene synthesized by a metallocene catalyst gas phase method as raw material, and 1 part of an antistatic agent is added, wherein the metallocene melt index is 1.0 g / 10min and the density is 0.85 g / cm3; a 40 μm antistatic polyethylene PE film is obtained by a three-layer co-extrusion blow molding process, the extrusion temperature is 180°C, and the blow-up ratio is 2.5; 5) Use laser plate making to obtain the corresponding anti-counterfeiting printing flexographic plate, and transfer the special anti-counterfeiting ink to the printing layer film through flexographic printing, with bright patterns printed on the front and dark patterns printed on the back; 6) A two-component polyurethane solvent-free adhesive is used between the layers to form a composite film. The printed layer and the barrier layer are laminated and aged at 45°C for 12 hours, and the barrier layer and the heat-sealing layer are laminated and aged at 45°C for 36 hours.

[0027] 7) After cooling to room temperature, cut the edges to obtain the finished roll film.

[0028] Example 2 A flexographic printing anti-counterfeiting high-activity dry yeast packaging composite film and a preparation method thereof, wherein the specific material structure is BOPP18 / AL7 / PE45.

[0029] The preparation method is as follows: 1) Preparation of printing layer: 100 parts of polypropylene pellets were placed into the barrel of the extruder, and 3 parts of anti-reflection masterbatch (TMB-5: aromatic dicarbonamide β-nucleating agent) were added. After melt extrusion, biaxial stretching was performed at a temperature of 235°C, a stretching ratio of 3.0x3.0, and a film thickness of 18 μm to obtain a biaxially oriented polypropylene film (BOPP). The obtained biaxially oriented polypropylene film (BOPP) was subjected to double-sided corona treatment under the conditions of a high-frequency voltage of 1000 V / m2, a film temperature of 45°C, and a dyne value of not less than 38. 2) Follow Figure 1 The anti-counterfeiting print is made into a printing plate by laser plate making, and the anti-counterfeiting ink is transferred to the printing layer by flexographic printing.

[0030] 3) Preparation of barrier layer: Aluminum film is deposited on the surface of linear low-density polyethylene film by vacuum evaporation method. A BOBST K5 EXPERT vacuum coating machine is used to deposit an AlOx layer with a thickness of 8-10 nm on the surface of the film to obtain an aluminum oxide film (AlOx-PE). 4) Preparation of heat-sealing layer: The outer layer and the middle layer are made of linear low-density PE with a melt index of 1.5 g / 10min and a density of 0.85 g / cm3; the inner layer is made of polyethylene synthesized by a metallocene catalyst gas phase method as raw material, and 2 parts of antistatic agent are added, wherein the metallocene melt index is 1.0 g / 10min and the density is 0.85 g / cm3; a 45 μm antistatic polyethylene PE film is obtained by a three-layer co-extrusion blow molding process, the extrusion temperature is 180°C, and the blow-up ratio is 2.5; 5) Use laser plate making to obtain the corresponding anti-counterfeiting printing flexographic plate, and transfer the special anti-counterfeiting ink to the printing layer film through flexographic printing, with bright patterns printed on the front and dark patterns printed on the back; 6) A two-component polyurethane solvent-free adhesive is used between the layers to form a composite film. The printed layer and the barrier layer are laminated and aged at 47°C for 12 hours, and the barrier layer and the heat-sealing layer are laminated and aged at 47°C for 36 hours.

[0031] 7) After cooling to room temperature, cut the edges to obtain the finished roll film.

[0032] Example 3 A flexographic printing anti-counterfeiting high-activity dry yeast packaging composite film and a preparation method thereof, wherein the specific material structure is BOPET12 / AL7 / PE50.

[0033] The preparation method is as follows: 1) Preparation of the printing layer: 100 parts of polyethylene terephthalate pellets were placed into the barrel of an extruder, and 5 parts of an anti-reflection masterbatch (model BRUGGOLEN P250, manufacturer Brüggemann) were added. After melt extrusion, biaxial stretching was performed, and the film thickness was controlled to be 12 μm to obtain a biaxially stretched polyethylene terephthalate film (BOPET). The obtained biaxially stretched polyethylene terephthalate film (BOPET) was subjected to double-sided corona treatment, and the corona treatment condition was a high-frequency voltage of 1000 V / m 2， The film temperature is 45°C, and the dyne value is not less than 50; the conditions for biaxial stretching after melt extrusion are: temperature 290°C, stretching ratio 3.0x3.0, 2) Follow Figure 1 The anti-counterfeiting print is made into a printing plate by laser plate making, and the anti-counterfeiting ink is transferred to the printing layer by flexographic printing.

[0034] 3) Preparation of barrier layer: Aluminum film is deposited on the surface of linear low-density polyethylene film by vacuum evaporation method. A BOBST K5 EXPERT vacuum coating machine is used to deposit an AlOx layer with a thickness of 8nm on the surface of the film to obtain an aluminum oxide film (AlOx-PE). 4) Preparation of heat seal layer: The outer and middle layers are made of linear low-density PE with a melt index of 1.5 g / 10min and a density of 0.85 g / cm3; the inner layer is made of polyethylene synthesized by metallocene catalyst gas phase method as raw material, and 3 parts of antistatic agent are added, of which the metallocene melt index is 1.0 g / 10min and the density is 0.85 g / cm 3 ; Through three-layer co-extrusion blow molding process, a 50 μm antistatic polyethylene PE film was obtained, the extrusion temperature was 180°C, and the blow ratio was 2.5; 5) Use laser plate making to obtain the corresponding anti-counterfeiting printing flexographic plate, and transfer the special anti-counterfeiting ink to the printing layer film through flexographic printing, with bright patterns printed on the front and dark patterns printed on the back; 6) A two-component polyurethane solvent-free adhesive is used between the layers to form a composite film. The printed layer and the barrier layer are laminated and aged at 46°C for 12 hours, and the barrier layer and the heat-sealing layer are laminated and aged at 46°C for 36 hours.

[0035] 7) After cooling to room temperature, cut the edges to obtain the finished roll film.

[0036] Comparative Example 1 A flexographic printing anti-counterfeiting high-activity dry yeast packaging composite film and a preparation method thereof, wherein the specific material structure is BOPET12 / AL7 / PE50.

[0037] The preparation method is as follows: 1) Preparation of printing layer: 100 parts of polyethylene terephthalate pellets were placed into the barrel of an extruder without adding a transparent masterbatch, and then melt-extruded and biaxially stretched. The film thickness was controlled to be 12 μm to obtain a biaxially stretched polyethylene terephthalate film (BOPET). The obtained biaxially stretched polyethylene terephthalate film (BOPET) was subjected to double-sided corona treatment under a high-frequency voltage of 1000 V / m 2， Film temperature 45°C, dyne value not less than 50; 2) Follow Figure 1 The anti-counterfeiting print is made into a printing plate by laser plate making, and the anti-counterfeiting ink is transferred to the printing layer by flexographic printing.

[0038] 3) Preparation of barrier layer: Aluminum film was deposited on the surface of linear low-density polyethylene film by vacuum evaporation method. A BOBST K5 EXPERT vacuum coating machine was used to deposit an AlOx layer with a thickness of 8 nm on the surface of the film to obtain an aluminum oxide film (AlOx-PE). 4) Preparation of heat seal layer: The outer and middle layers are made of linear low-density PE with a melt index of 1.5 g / 10min and a density of 0.85 g / cm3; the inner layer is made of polyethylene synthesized by metallocene catalyst gas phase method as raw material, and 3 parts of antistatic agent are added, of which the metallocene melt index is 1.0 g / 10min and the density is 0.85 g / cm 3 ; Through three-layer co-extrusion blow molding process, a 50 μm antistatic polyethylene PE film was obtained, the extrusion temperature was 180°C, and the blow ratio was 2.5; 5) Use laser plate making to obtain the corresponding anti-counterfeiting printing flexographic plate, and transfer the special anti-counterfeiting ink to the printing layer film through flexographic printing, with bright patterns printed on the front and dark patterns printed on the back; 6) A two-component polyurethane solvent-free adhesive is used between the layers to form a composite film. The printed layer and the barrier layer are laminated and aged at 46°C for 12 hours, and the barrier layer and the heat-sealing layer are laminated and aged at 46°C for 36 hours.

[0039] 7) After cooling to room temperature, cut the edges to obtain the finished roll film.

[0040] Printing layer performance test: light transmittance and haze test refer to GB / T2410-2008.

[0041] Composite film performance test: The thickness of the composite film is tested in accordance with GB / T 6672-2001, the peel strength test is carried out in accordance with GB / T8808-1988; the heat seal strength is carried out in accordance with QB / T 2358-1998; the water vapor transmission rate is carried out in accordance with GB / T 21529-2008; the oxygen transmission rate is carried out in accordance with GB / T 1038.1-2022; the solvent residue test is carried out in accordance with GB / T 10004-2008.

[0042] It can be seen from Table 1 that the composite films in the three embodiments have good physical properties. The yeast packaging composite film with low oxygen permeability and water vapor permeability can greatly extend the shelf life of the packaging. The tensile strength and tear strength of the film with the anti-reflection masterbatch added are stronger than those of the film without the masterbatch. From the appearance, the printing accuracy and brightness of Examples 1, 2, and 3 are better than those of the comparative example. The printing film ink is more uniform than that of the comparative example without the masterbatch. The printing accuracy of the film with the masterbatch added is significantly better than that of the film without the masterbatch.

[0043] Table 1 Comparison of Examples

[0044] This packaging film uses flexographic printing to print anti-counterfeiting patterns. It takes advantage of the high line count of flexographic printing and is suitable for high-precision anti-counterfeiting patterns. It uses a program random arrangement method to ensure the randomness of the anti-counterfeiting pattern and reduce the possibility of counterfeiting. At the same time, anti-reflection masterbatch is added to the printing film to ensure the accuracy of the printing appearance, and the printing film is double-sided corona to increase the firmness of the printing ink. The vacuum-plated aluminum oxide film is used as the barrier layer to ensure the barrier properties of the packaging while reducing aluminum pollution.

[0045] The technical solution of the present invention is explained through the above embodiments, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above specific embodiments to be implemented. Any improvements made by technicians in the relevant field based on the present invention, or equivalent replacement of the materials selected by the present invention, etc., fall within the scope of protection of the patent.

Claims

1. A flexographic printing anti-counterfeiting highly active dry yeast packaging composite film, characterized in that: The composite film is a composite film with a three-layer structure, wherein the outer layer is a printing layer (1), the middle barrier layer (2), and the inner layer is a heat-sealing layer (3). Ultraviolet invisible ink is printed on the film, and adhesives are used to laminate the layers.

2. The flexographic printing anti-counterfeiting highly active dry yeast packaging composite film according to claim 1, characterized in that: The printing layer is a double corona biaxially oriented polypropylene (BOPP) or biaxially oriented polyethylene terephthalate (BOPET) film substrate, the middle barrier layer (2) is an aluminum foil or an aluminized polyethylene terephthalate film, and the inner printing layer (3) is an antistatic PE film; a two-component polyurethane solvent-free adhesive is used between the layers to form a composite film.

3. The flexographic printing anti-counterfeiting highly active dry yeast packaging composite film according to claim 1, characterized in that: The printing method is flexographic printing.

4. A method for preparing a flexographic printing anti-counterfeiting high-activity dry yeast packaging composite film, characterized in that: The preparation method comprises the following steps: S1. Putting polyethylene terephthalate pellets or polypropylene pellets into the barrel of an extruder, adding an anti-reflection masterbatch, and performing biaxial stretching after melt extrusion to obtain a biaxially stretched polyethylene terephthalate film (BOPET) or a biaxially stretched polypropylene film (BOPP), and performing double-sided corona treatment on the obtained printed film; S2, using vacuum aluminum plating technology, under vacuum conditions, evaporating an AlOx layer to obtain a longitudinally stretched polyethylene AlOx-PE film; S3, using laser plate making to obtain the corresponding anti-counterfeiting printing flexographic printing plate, transferring the anti-counterfeiting ink to the printing layer film through flexographic printing, with bright patterns printed on the front and dark patterns printed on the back; S4, using a longitudinally stretched polyethylene AlOx-PE film obtained by vacuum aluminum plating as a barrier layer; S5, using polyethylene synthesized by a metallocene catalyst gas phase method as a raw material, adding an antistatic agent, and using a three-layer co-extrusion blow molding process to process it into a heat-sealing layer film; S6, bonding the printed layer, the barrier layer and the heat-sealing layer by using an adhesive to obtain a composite film; S7, placing the composite film in a curing chamber for curing, and cutting it after cooling to obtain a finished composite film roll.

5. The method for preparing the flexographic printing anti-counterfeiting highly active dry yeast packaging composite film according to claim 1, characterized in that: In the step S2, the rubber flexographic printing plate is made by laser plate making, the circumference of the printing plate is 450-550 mm, the screen line count is 130-135 LDI, and the thickness is 1.35-1.45 mm; the screen line count of the anilox roller is 350-450 L / cm; Preferably, the circumference of the printing plate is 500 mm, the screen line count is 133 LDI, and the thickness is 1.44 mm; the screen line count of the anilox roller is 400 L / cm.

6. The method for preparing the flexographic printing anti-counterfeiting highly active dry yeast packaging composite film according to claim 1, characterized in that: In step S2, the anti-counterfeiting print is composed of a front bright pattern and six back dark patterns; The order of anti-counterfeiting stamps is randomly generated; The anti-counterfeiting printing adopts Solimax special anti-counterfeiting ink.

7. The method for preparing the flexographic printing anti-counterfeiting highly active dry yeast packaging composite film according to claim 1, characterized in that: In the step S2, the printing method is flexographic printing. When the flexographic printing is performed, the positions of the plate rollers are specifically arranged to separate the anti-counterfeiting printing roller from the large-format background color.

8. The method for preparing the flexographic printing anti-counterfeiting highly active dry yeast packaging composite film according to claim 1, characterized in that: In step S3, the film substrate used for vacuum AlOx deposition is a linear low-density PE film, on which a 8-10 nm AlOx layer is evaporated; the vacuum aluminum deposition conditions are 5*10 -2 ~ 6*10 -2 Pa.

9. The method for preparing the flexographic printing anti-counterfeiting highly active dry yeast packaging composite film according to claim 1, characterized in that: In step S4, the outer layer and the middle layer are made of linear low-density PE with a melt index of 1.0-2.0 g / 10min and a density of 0.8-0.9 g / cm 3 The inner layer is made of polyethylene synthesized by metallocene catalyst gas phase method, and 1-3 parts of antistatic agent are added, wherein the metallocene melt index is 1.0-2.0 g / 10min, the density is 0.85-0.9g / cm 3 ; In step S5, the adhesive is a two-component polyurethane solvent-free adhesive; In step S5, the layers are compounded without solvent; In step S6, each composite layer needs to be cured separately.

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