Rubbing-resistant film, high-barrier packaging bag and preparation method

Abstract

The invention discloses a rubbing-resistant film, a high-barrier packaging bag and a preparation method, the rubbing-resistant film comprises a PET layer, a metal aluminum layer, a polyamide layer, a polyvinyl alcohol coating and a PE layer which are sequentially attached, and the PE layer comprises a first surface layer, a middle layer and a second surface layer; the first surface layer and the second surface layer are consistent in thickness, material and preparation process, and each of the first surface layer and the second surface layer comprises metallocene, linear low-density polyethylene and an opening slipping agent; the middle layer comprises metallocene, linear low-density polyethylene, a polyolefin elastomer, polypropylene and a maleic anhydride grafted copolymer, the bag is an ultrahigh-barrier rubbing-resistant packaging bag, tests show that the 24-hour gas barrier property can reach 0.1 cc or below, the heat sealing strength is larger than or equal to 90 N / 15 mm, and the leakage point is smaller than or equal to 3 after rubbing is conducted for 8100 times in the rubbing-resistant test.

Description

Technical Field

[0001] The present application relates to the technical field of packaging bags, and specifically to a rubbing-resistant film, a high-barrier packaging bag, and a preparation method thereof. Background Art

[0002] Ultra-high barrier and rubbing-resistant film materials are developed for the storage and transportation of new energy power battery raw materials. With the continuous growth of new energy production capacity, the demand for the storage and transportation of powdered lithium battery raw materials continues to expand.

[0003] Due to the strong oxidizing properties and extremely low copper metal pollution characteristics of power batteries, a variety of film materials with different barrier properties are needed to be superimposed and supplemented. At the same time, after long-distance transportation, the product itself will produce flexible cracks in the bag due to rubbing and deformation, which will reduce the barrier properties of the bag. High barrier materials can effectively prevent external oxygen, water vapor, odor, etc. from entering the packaging, and by reducing the penetration of oxygen and moisture, the quality of the product is not affected.

[0004] In addition to meeting the requirements of ultra-high barrier properties, good rubbing resistance is also required. During logistics and transportation, packaging may experience various physical stresses, including squeezing, folding, and friction. Packaging with good rubbing resistance can maintain its integrity under these conditions, avoiding product damage or contamination caused by packaging damage.

[0005] Therefore, a rubbing-resistant film and high-barrier packaging bag is expected by the market. Summary of the invention

[0006] The purpose of the present application is to provide a rubbing-resistant film, a high-barrier packaging bag and a preparation method. The film is an ultra-high barrier and rubbing-resistant packaging bag. After testing, the gas barrier performance for 24 hours reaches less than 0.1cc, the heat sealing strength is ≥90N / 15mm, and the leakage points for 8100 rubbing times in the rubbing resistance test are ≤3.

[0007] To achieve the above-mentioned objectives, the present application provides the following technical solutions: a rub-resistant film and a high-barrier packaging bag, comprising a PET layer, a metal aluminum layer, a polyamide layer, a polyvinyl alcohol coating and a PE layer laminated in sequence, the PE layer comprising a first surface layer, an intermediate layer and a second surface layer; the thickness, material and preparation process of the first surface layer and the second surface layer are consistent, the first surface layer and the second surface layer both comprise metallocene, linear low-density polyethylene and an opening lubricant; the intermediate layer comprises metallocene, linear low-density polyethylene, a polyolefin elastomer, polypropylene and a maleic anhydride grafted copolymer.

[0008] Since the traditional aluminum foil is easy to crack during actual use, resulting in a decrease in barrier performance, adding a layer of PVA coating can greatly reduce the decrease in oxygen permeability caused by the cracking of the aluminum foil. At the same time, combined with the high rubbing-resistant PE film layer, the number of flexible cracks after rubbing can be better controlled. After testing, the rubbing-resistant film and high-barrier packaging bag meet the 24-hour gas barrier performance of less than 0.1cc, the heat sealing strength ≥90N / 15mm, and the anti-rubbing test meets the leakage point of 8100 rubbing times ≤3.

[0009] Preferably, the thickness of the PET layer is 9-13 μm, the thickness of the metal aluminum layer is 5-8 μm, the thickness of the polyamide layer is 13-16 μm, the thickness of the polyvinyl alcohol coating is 6-10 μm, and the thickness of the PE layer is 111-140 μm.

[0010] Preferably, the metallocene content of the PE layer is 25-40%, the linear low-density polyethylene content is 50-70%, the opening lubricant content is 0.2-0.8%, the polyolefin elastomer content is 3-5%, the polypropylene content is 3-5%, and the maleic anhydride graft copolymer content is 2-4%. After testing, the PE layer of this formula can improve the rubbing resistance of the film as well as the stability of the film blowing and the compatibility between resins. The measured rubbing performance can be improved by more than 50% compared with the traditional PE film for packaging.

[0011] Preferably, the first surface layer and the second surface layer each include 7.5-12% metallocene, 15-21% linear low density polyethylene and 0.1-0.4% opening lubricant, and the middle layer includes 10-16% metallocene, 20-28% linear low density polyethylene, 3-5% polyolefin elastomer, 3-5% polypropylene and 2-4% maleic anhydride graft copolymer.

[0012] The present application also provides a method for preparing a rubbing-resistant film and a high-barrier packaging bag, which is used to prepare any of the rubbing-resistant films and high-barrier packaging bags described above, comprising: Step 1: The PET layer is laminated with the metal aluminum layer by applying glue on the PET layer through a solvent-free lamination process; Step 2: The metal aluminum layer is laminated with the polyamide layer by applying glue on the metal aluminum layer through a solvent-free lamination process; Step 3: The polyvinyl alcohol coating is formed by directly coating the polyvinyl alcohol on the polyamide layer; Step 4: The PE layer is compounded with the PVA coating using a solvent-free compounding process.

[0013] Preferably, the PE layer is blown by a film blowing machine to simultaneously blow the first surface layer, the middle layer and the second surface layer to form a three-layer co-extruded film.

[0014] Preferably, the process steps of film blowing include: Step 1: The raw materials of the first surface layer, the middle layer and the second surface layer are introduced into the film blowing machine through the inlet of the film blowing machine; Step 2: respectively set the regional temperature and speed of the screw corresponding to the first surface layer, the middle layer and the second surface layer, monitor the pressure and current of the screw corresponding to each layer to ensure that it does not exceed the set warning value, and input the raw materials of the first surface layer, the middle layer and the second surface layer into the corresponding screw after the state is stable; Step 3: Set the regional temperature of the die head to ensure uniform melt flow, control the upper traction speed for film blowing, and ensure uniform film thickness; Step 4: Corona treatment of the blown film to improve printing and lamination properties.

[0015] Preferably, the screws corresponding to the first surface layer, the middle layer and the second surface layer each include nine zone temperatures. The nine regions of the first surface layer and the second surface layer have the same temperature, and the nine regions of each layer include surface screw T1: 155-165°C, surface screw T2: 160-170°C, surface screw T3: 165-175°C, surface screw T4: 170-180°C, surface screw T5: 170-180°C, surface screw T6: 170-180°C, surface screw T7: 170-180°C, surface screw T8: 170-180°C, surface screw T9: 170-180°C; The nine zone temperatures of the middle layer include intermediate screw T1: 160-170°C, intermediate screw T2: 165-175°C, intermediate screw T3: 170-180°C, intermediate screw T4: 175-185°C, intermediate screw T5: 175-185°C, intermediate screw T6: 175-185°C, intermediate screw T7: 175-185°C, intermediate screw T8: 175-185°C, and intermediate screw T9: 175-185°C.

[0016] Preferably, the die includes five temperature zones, including die T1: 170-180°C, die T2: 170-180°C, die T3: 170-180°C, die T4: 167-177°C, and die T5: 165-175°C.

[0017] Preferably, the screw speeds corresponding to the first surface layer, the middle layer and the second surface layer are: the screw speed of the first surface layer is 35.8-45.8r / min, the screw speed of the middle layer is 42.3-52.3r / min, and the screw speed of the second surface layer is 35.5-45.5r / min. The pressure setting warning values ​​of the three screws are all ≤60MPa, the current setting warning value of the first surface layer screw is ≤117A, the current setting warning value of the middle layer screw is ≤152A, and the current setting warning value of the second surface layer screw is ≤117A. The upper traction speed is 10.7-14.7m / min, and the corona treatment is ≥42 dynes.

[0018] Compared with the prior art, the beneficial effects of this application are: 1. The rubbing-resistant film and high-barrier packaging bag have been tested to meet the gas barrier performance of less than 0.1cc for 24 hours, the heat sealing strength is ≥90N / 15mm, and the leakage points of 8100 rubbing times in the rubbing-resistant test are ≤3; 2. The PE layer in this application can improve the rubbing resistance of the film as well as the stability of the film blowing and the compatibility between resins. The measured rubbing performance can be improved by more than 50% compared with the traditional PE film for packaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a data analysis diagram of the rubbing resistance test of the PE film layer of the present invention and the existing PE film; Figure 2 The present invention is an attempt to analyze the rubbing resistance test data of the packaging bag of the present invention and the existing packaging bag. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present application are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0021] A rub-resistant film and a high-barrier packaging bag, comprising a PET layer, a metal aluminum layer, a polyamide layer, a polyvinyl alcohol coating layer, and a PE layer that are sequentially laminated. Among them, the thickness of the PET layer is 12 μm, the thickness of the metal aluminum layer is 7 μm, the thickness of the polyamide layer is 15 μm, the thickness of the polyvinyl alcohol coating layer is 7 μm, and the thickness of the PE layer is 125 μm. Among them, the PE layer includes a first surface layer, an intermediate layer, and a second surface layer. Both the first surface layer and the second surface layer include 9% metallocene, 18% linear low-density polyethylene, and 0.3% antiblocking and slip agent. The intermediate layer includes 12% metallocene, 24% linear low-density polyethylene, 3.4% polyolefin elastomer, 3% polypropylene, and 3% maleic anhydride graft copolymer. The PE has good flexibility and impact resistance; the PET has excellent mechanical strength and rigidity, is harder and more brittle than the PE, but the PET has good transparency, and the PET has excellent gas barrier properties, and the PET also has good chemical resistance and ultraviolet resistance; the metal aluminum layer can make the packaging bag have good corrosion resistance; the PVA has good barrier properties and thermal stability; the PA has the advantages of high strength and toughness, and has high tensile strength and impact resistance, good wear resistance and friction properties; the POE has the advantages of high elasticity, low-temperature toughness, and chemical resistance, the PP has high strength and rigidity, and has good chemical resistance; the linear low-density polyethylene has good mechanical properties, transparency, and flexibility; the metallocene can catalyze the PE resin, can significantly improve the flexibility, rub resistance, and processing performance of the film material, and ensure its reliability and durability in a complex environment. Through research and development and design, first, a rub-resistant PE film formulation and preparation method were developed, and then the rub-resistant PE film was introduced into the packaging bag formulation for further research and development, and a formulation and preparation method for a high-barrier and rub-resistant packaging bag were obtained. It was found that the rub resistance of the PE film of this application, the stability of film blowing, and the compatibility between resins are very good. The measured rub resistance of the PE film of this application can be improved by more than 50% compared with the traditional packaging PE film. It was found that the packaging bag of this application can greatly reduce the decrease in oxygen transmission rate caused by the cracking of the aluminum foil. At the same time, combined with the high rub-resistant PE film layer, the number of flexible cracks after rubbing can be better controlled.

[0022] Among them, the PET layer is laminated with the metal aluminum layer by coating glue on the PET layer through a solventless lamination process; the metal aluminum layer is laminated with the polyamide layer by coating glue on the metal aluminum layer through a solventless lamination process; the polyvinyl alcohol coating layer is formed by directly coating polyvinyl alcohol on the polyamide layer; the PE layer is laminated with the PVA coating layer using a solventless lamination process.

[0023] It should be noted that the PE layer is blown into a three-layer coextruded film by simultaneously blowing the first surface layer, the intermediate layer, and the second surface layer through a blown film machine. The specific blown film process includes: Step 1: The raw materials of the first surface layer, the middle layer and the second surface layer are introduced into the film blowing machine through the inlet of the film blowing machine.

[0024] Step 2: Set the area temperature and speed of the screw corresponding to the first surface layer, the middle layer and the second surface layer respectively, monitor the pressure and current of the screw corresponding to each layer to ensure that it does not exceed the set warning value, and input the raw materials of the first surface layer, the middle layer and the second surface layer into the corresponding screw after the state is stable. Specifically, The screws corresponding to the first surface layer, the middle layer and the second surface layer each include nine zone temperatures. The temperatures of the nine zones of the first surface layer and the second surface layer are the same, and the temperatures of the nine zones of each layer include surface screw T1: 160°C, surface screw T2: 165°C, surface screw T3: 170°C, surface screw T4: 175°C, surface screw T5: 175°C, surface screw T6: 175°C, surface screw T7: 175°C, surface screw T8: 175°C, and surface screw T9: 175°C.

[0025] The nine zone temperatures of the middle layer include intermediate screw T1: 165°C, intermediate screw T2: 170°C, intermediate screw T3: 175°C, intermediate screw T4: 180°C, intermediate screw T5: 180°C, intermediate screw T6: 180°C, intermediate screw T7: 180°C, intermediate screw T8: 180°C, and intermediate screw T9: 180°C.

[0026] Step 3: Set the regional temperature of the die to ensure uniform melt flow. The die includes five regional temperatures, including die T1: 175°C, die T2: 175°C, die T3: 175°C, die T4: 172°C, die T5: 170°C. Control the upper traction speed at 12.7m / min for film blowing to ensure uniform film thickness.

[0027] The screw speeds corresponding to the first surface layer, middle layer and second surface layer are: the screw speed of the first surface layer is 40.8r / min, the screw speed of the middle layer is 47.3r / min, and the screw speed of the second surface layer is 40.5r / min. The pressure setting warning values ​​of the three screws are all ≤60MPa, the current setting warning value of the first surface layer screw is ≤117A, the current setting warning value of the middle layer screw is ≤152A, and the current setting warning value of the second surface layer screw is ≤117A.

[0028] Step 4: Corona treat the blown film to a level of ≥42 dynes to improve printing and lamination performance.

[0029] The PE layer of the present application was subjected to 8100 times of rubbing resistance test, and the specific data are as follows: Among them, the diameter > 2mm is counted as "large" points, and the diameter ≤ 2mm is counted as "small" points. Figure 1 As shown, the component ratio of the packaging bag of the present application is: the first surface layer and the second surface layer each include 9% metallocene, 18% linear low-density polyethylene and 0.3% opening lubricant, and the middle layer includes 12% metallocene, 24% linear low-density polyethylene, 3.4% polyolefin elastomer, 3% polypropylene and 3% maleic anhydride graft copolymer.

[0030] .

[0031] The rubbing resistance test was carried out 8100 times on the rubbing resistance film and high barrier packaging bag of this application. The specific data are as follows: Among them, the diameter > 2mm is counted as a "large" point, and the diameter ≤ 2mm is counted as a "small" point. The bar chart is as follows Figure 2 As shown, the component ratio of the packaging bag parameters of the present application is: the thickness of the PET layer is 12μm, the thickness of the metal aluminum layer is 7μm, the thickness of the polyamide layer is 15μm, the thickness of the polyvinyl alcohol coating is 7μm, and the thickness of the PE layer is 125μm, wherein the PE layer includes a first surface layer, an intermediate layer and a second surface layer, the first surface layer and the second surface layer both include 9% of metallocene, 18% of linear low-density polyethylene and 0.3% of an opening lubricant, and the intermediate layer includes 12% of metallocene, 24% of linear low-density polyethylene, 3.4% of polyolefin elastomer, 3% of polypropylene and 3% of maleic anhydride grafted copolymer.

[0032] .

[0033] According to the above test results, the PE film of the present application has greatly improved rubbing resistance compared with the existing PE film, and even the large-sized test sample can be rubbed 8100 times without leakage. Compared with the existing packaging bags, the packaging bags of the present application have greatly improved rubbing resistance and excellent performance.

[0034] The methods used in the present invention, unless otherwise specified, are conventional methods in the art.

[0035] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent transformation made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A rubbing-resistant film and high-barrier packaging bag, characterized in that: It includes a PET layer, a metal aluminum layer, a polyamide layer, a polyvinyl alcohol coating and a PE layer laminated in sequence. The PE layer includes a first surface layer, an intermediate layer and a second surface layer; The thickness, material and preparation process of the first surface layer and the second surface layer are consistent, and the first surface layer and the second surface layer both include metallocene, linear low-density polyethylene and an opening lubricant; The intermediate layer includes metallocene, linear low density polyethylene, polyolefin elastomer, polypropylene and maleic anhydride graft copolymer.

2. The rubbing-resistant film and high-barrier packaging bag according to claim 1, characterized in that: The thickness of the PET layer is 9-13 μm, the thickness of the metal aluminum layer is 5-8 μm, the thickness of the polyamide layer is 13-16 μm, the thickness of the polyvinyl alcohol coating is 6-10 μm, and the thickness of the PE layer is 111-140 μm.

3. The rubbing-resistant film and high-barrier packaging bag according to claim 1 or 2, characterized in that: The PE layer has a metallocene content of 25-40%, a linear low-density polyethylene content of 50-70%, an opening lubricant content of 0.2-0.8%, a polyolefin elastomer content of 3-5%, a polypropylene content of 3-5%, and a maleic anhydride graft copolymer content of 2-4%.

4. The rubbing-resistant film and high-barrier packaging bag according to claim 3, characterized in that: The first surface layer and the second surface layer both include 7.5-12% metallocene, 15-21% linear low density polyethylene and 0.1-0.4% opening lubricant, and the middle layer includes 10-16% metallocene, 20-28% linear low density polyethylene, 3-5% polyolefin elastomer, 3-5% polypropylene and 2-4% maleic anhydride graft copolymer.

5. A method for preparing a rubbing-resistant film and a high-barrier packaging bag, used for preparing the rubbing-resistant film and the high-barrier packaging bag as claimed in any one of claims 1 to 4, characterized in that: include: Step 1: The PET layer is laminated with the metal aluminum layer by applying glue on the PET layer through a solvent-free lamination process; Step 2: The metal aluminum layer is laminated with the polyamide layer by applying glue on the metal aluminum layer through a solvent-free lamination process; Step 3: The polyvinyl alcohol coating is formed by directly coating the polyvinyl alcohol on the polyamide layer; Step 4: The PE layer is compounded with the PVA coating using a solvent-free compounding process.

6. The method for preparing the rubbing-resistant film and high-barrier packaging bag according to claim 5, characterized in that: The PE layer is blown by a film blowing machine to simultaneously blow the first surface layer, the middle layer and the second surface layer to form a three-layer co-extruded film.

7. The method for preparing the rubbing-resistant film and high-barrier packaging bag according to claim 6, characterized in that: The process steps of film blowing include: Step 1: The raw materials of the first surface layer, the middle layer and the second surface layer are introduced into the film blowing machine through the inlet of the film blowing machine; Step 2: respectively set the regional temperature and speed of the screw corresponding to the first surface layer, the middle layer and the second surface layer, monitor the pressure and current of the screw corresponding to each layer to ensure that it does not exceed the set warning value, and input the raw materials of the first surface layer, the middle layer and the second surface layer into the corresponding screw after the state is stable; Step 3: Set the regional temperature of the die head to ensure uniform melt flow, control the upper traction speed for film blowing, and ensure uniform film thickness; Step 4: Corona treatment of the blown film to improve printing and lamination properties.

8. The method for preparing the rubbing-resistant film and high-barrier packaging bag according to claim 7, characterized in that: The screws corresponding to the first surface layer, the middle layer and the second surface layer each include nine zone temperatures. The nine regions of the first surface layer and the second surface layer have the same temperature, and the nine regions of each layer include surface screw T1: 155-165°C, surface screw T2: 160-170°C, surface screw T3: 165-175°C, surface screw T4: 170-180°C, surface screw T5: 170-180°C, surface screw T6: 170-180°C, surface screw T7: 170-180°C, surface screw T8: 170-180°C, surface screw T9: 170-180°C; The nine zone temperatures of the middle layer include intermediate screw T1: 160-170°C, intermediate screw T2: 165-175°C, intermediate screw T3: 170-180°C, intermediate screw T4: 175-185°C, intermediate screw T5: 175-185°C, intermediate screw T6: 175-185°C, intermediate screw T7: 175-185°C, intermediate screw T8: 175-185°C, and intermediate screw T9: 175-185°C.

9. The method for preparing the rubbing-resistant film and high-barrier packaging bag according to claim 7, characterized in that: The die includes five temperature zones, including die T1: 170-180°C, die T2: 170-180°C, die T3: 170-180°C, die T4: 167-177°C, and die T5: 165-175°C.

10. The method for preparing the rubbing-resistant film and high-barrier packaging bag according to claim 7, characterized in that: The screw speeds corresponding to the first surface layer, middle layer and second surface layer are: the screw speed of the first surface layer is 35.8-45.8r / min, the screw speed of the middle layer is 42.3-52.3r / min, and the screw speed of the second surface layer is 35.5-45.5r / min. The pressure setting warning values ​​of the three screws are all ≤60MPa, the current setting warning value of the first surface layer screw is ≤117A, the current setting warning value of the middle layer screw is ≤152A, and the current setting warning value of the second surface layer screw is ≤117A. The upper traction speed is 10.7-14.7m / min, and the corona treatment is ≥42 dynes.

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