High-impact multilayer heavy duty packaging film composition and multilayer heavy duty packaging film and use thereof

Abstract

The application relates to the technical field of packaging materials, and discloses a high-impact multilayer heavy packaging film composition and a multilayer heavy packaging film and application thereof. The composition comprises an outer layer material, a core layer material and an inner layer material, wherein the core layer material contains linear low-density polyethylene, polypropylene and optional metallocene polyethylene; the components of the outer layer material and the components of the inner layer material are the same or different, and each contains linear low-density polyethylene, metallocene polyethylene, high-density polyethylene and ethylene-vinyl acetate copolymer or polyolefin elastomer. The multilayer heavy packaging film can improve the dart impact performance of the multilayer heavy packaging film.

Description

Technical Field

[0001] This invention relates to the field of packaging materials technology, specifically to a high-impact multilayer heavy-duty packaging film composition and multilayer heavy-duty packaging film and their applications. Background Technology

[0002] FFS film for heavy packaging (FFS is an abbreviation for Form, Fill and Seal integrated) has seen rapid development due to its advantages such as fast packaging, no pollution, good sealing and printability.

[0003] Currently, overseas manufacturers mainly achieve thinning while maintaining mechanical properties by developing high-performance metallocene polyethylene, thereby reducing packaging costs.

[0004] Polypropylene (PP) has high crystallinity and superior strength, rigidity, and heat resistance compared to polyethylene. It also exhibits high-temperature creep resistance. Therefore, the development of PP / PE heavy-duty packaging bags is of great significance, but there is currently limited research on this topic.

[0005] CN102501526A discloses a cast polypropylene heavy packaging film, which comprises a heat-sealing layer, a core layer, and a corona layer. The heat-sealing layer, core layer, and corona layer are all blends of polypropylene and an elastomer. The heat-sealing layer contains 20-30% elastomer, the core layer contains 30-50% elastomer, and the corona layer contains 10-20% elastomer. The polypropylene is homopolymer polypropylene, binary copolymer polypropylene, or ternary copolymer polypropylene. The elastomer is an ethylene-α-olefin copolymer. The density of the elastomer is 0.85-0.88 g / cm³. 3 However, a drawback is that both the inner and outer layers contain PP, which affects the material's impact resistance. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of insufficient impact resistance of existing films and to provide a high-impact multilayer heavy-duty packaging film composition, a multilayer heavy-duty packaging film and its application. Due to the addition of PP, EVA and POE, the multilayer heavy-duty packaging film can simultaneously improve the tensile strength and impact resistance (i.e., dart impact resistance) of the multilayer heavy-duty packaging film.

[0007] To achieve the above objectives, a first aspect of the present invention provides a heavy-duty packaging film composition, the composition comprising an outer layer material, a core layer material, and an inner layer material, wherein:

[0008] The core material contains linear low-density polyethylene, polypropylene, and optionally metallocene polyethylene;

[0009] The outer layer material may have the same or different components as the inner layer material, each containing linear low-density polyethylene, metallocene polyethylene, high-density polyethylene, and ethylene-vinyl acetate copolymer or polyolefin elastomer.

[0010] A second aspect of the present invention provides a heavy packaging film made from the aforementioned composition, wherein the heavy packaging film comprises at least an outer layer, a core layer and an inner layer stacked sequentially, wherein the outer layer is obtained by extruding an outer layer material, the core layer is obtained by extruding a core layer material, and the inner layer is obtained by extruding an inner layer material.

[0011] A third aspect of the present invention provides the application of the aforementioned heavy-duty packaging film in one or more of resin packaging, cement packaging, and rice packaging.

[0012] The above technical solution involves the coordinated blending of polypropylene with high crystallinity, high strength, and high stiffness with flexible polyethylene, and the introduction of POE and EVA to improve toughness. Combined with multilayer blown film technology, a high-strength and high-impact multilayer film is prepared. Detailed Implementation

[0013] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0014] A first aspect of the present invention provides a heavy-duty packaging film composition, the composition comprising an outer layer material, a core layer material, and an inner layer material, wherein:

[0015] The core material contains linear low-density polyethylene, polypropylene, and optionally metallocene polyethylene;

[0016] The outer layer material may have the same or different components as the inner layer material, each containing linear low-density polyethylene, metallocene polyethylene, high-density polyethylene, and ethylene-vinyl acetate copolymer or polyolefin elastomer.

[0017] According to the present invention, based on the total weight of the outer layer material, the content of linear low-density polyethylene is 20-60% by weight, the content of metallocene polyethylene is 20-70% by weight, the content of high-density polyethylene is 5-30% by weight, and the content of ethylene-vinyl acetate copolymer or polyolefin elastomer is 5-30% by weight; preferably, based on the total weight of the outer layer material, the content of linear low-density polyethylene is 20-50% by weight, the content of metallocene polyethylene is 20-50% by weight, the content of high-density polyethylene is 5-30% by weight, and the content of ethylene-vinyl acetate copolymer or polyolefin elastomer is 5-30% by weight; more preferably, based on the total weight of the outer layer material, the content of linear low-density polyethylene is 30-50% by weight, the content of metallocene polyethylene is 40-50% by weight, the content of high-density polyethylene is 10-15% by weight, and the content of ethylene-vinyl acetate copolymer or polyolefin elastomer is 10-15% by weight. In this invention, limiting the content of each component in the outer layer material to the range described above can improve the toughness and impact resistance of the film.

[0018] According to the present invention, based on the total weight of the inner layer material, the content of linear low-density polyethylene is 20-60% by weight, the content of metallocene polyethylene is 20-70% by weight, the content of high-density polyethylene is 5-30% by weight, and the content of ethylene-vinyl acetate copolymer or polyolefin elastomer is 5-30% by weight; preferably, based on the total weight of the inner layer material, the content of linear low-density polyethylene is 20-50% by weight, the content of metallocene polyethylene is 20-50% by weight, the content of high-density polyethylene is 5-30% by weight, and the content of ethylene-vinyl acetate copolymer or polyolefin elastomer is 5-30% by weight; more preferably, based on the total weight of the inner layer material, the content of linear low-density polyethylene is 30-40% by weight, the content of metallocene polyethylene is 40-50% by weight, the content of high-density polyethylene is 10-15% by weight, and the content of ethylene-vinyl acetate copolymer or polyolefin elastomer is 10-15% by weight. In this invention, limiting the content of each component in the inner layer material to the range described above can improve the toughness and impact resistance of the film.

[0019] According to the present invention, based on the total weight of the core layer material, the content of linear low-density polyethylene is 20-80% by weight, the content of polypropylene is 20-80% by weight, and the content of metallocene polyethylene is 0-40% by weight; preferably, based on the total weight of the core layer material, the content of linear low-density polyethylene is 20-70% by weight, the content of polypropylene is 20-70% by weight, and the content of metallocene polyethylene is 0-30% by weight; more preferably, based on the total weight of the core layer material, the content of linear low-density polyethylene is 20-40% by weight, the content of polypropylene is 50-60% by weight, and the content of metallocene polyethylene is 10-20% by weight. In the present invention, limiting the content of each component in the core layer material to the aforementioned range can improve the rigidity of the film.

[0020] According to the present invention, the polypropylene is homopolymer polypropylene, binary copolymer polypropylene, or ternary copolymer polypropylene; preferably, the binary copolymer polypropylene is a copolymer of propylene and ethylene monomers, and the molar content of ethylene monomers in the binary copolymer is 2-20 mol%, preferably 5-15 mol%.

[0021] According to the present invention, the ternary copolymer polypropylene is a ternary atactic polypropylene of polypropylene, 1-butene, and ethylene.

[0022] According to the present invention, the polypropylene (PP) has a melt flow rate of 0.3-10 g / 10 min at 230°C under a load of 2.16 kg density and a density of 0.86-0.96 g / cm³. 3 The melting point is 130-160℃; preferably, the polypropylene has a melt flow rate of 0.35-5 g / 10 min at 230℃ under a load of 2.16 kg density, and a density of 0.86-0.94 g / cm³. 3 Its melting point is 130-150℃.

[0023] According to the present invention, the linear low-density polyethylene (LLDPE) has a melt flow rate of 0.3-10 g / 10 min at 190°C under a load of 2.16 kg and a density of 0.910-0.940 g / cm³. 3 The melting point is 110-125℃; preferably, the linear low-density polyethylene has a melt flow rate of 0.3-5 g / 10 min at 190℃ under a 2.16 kg load and a density of 0.910-0.924 g / cm³. 3 Its melting point is 110-120℃.

[0024] According to the present invention, the metallocene polyethylene has a melt flow rate of 0.1-10 g / 10 min at 190°C under a load of 2.16 kg and a density of 0.85-0.94 g / cm³. 3 The melting point is 110-125℃; preferably, the metallocene polyethylene has a melt flow rate of 0.1-5 g / 10 min at 190℃ under a 2.16 kg load and a density of 0.85-0.92 g / cm³. 3 Its melting point is 110-120℃.

[0025] According to the present invention, the high-density polyethylene (HDPE) has a melt flow rate of 0.05-5 g / 10 min at 190°C under a load of 2.16 kg and a density of 0.94-0.96 g / cm³. 3 The melting point is 125-135℃; preferably, the high-density polyethylene has a melt flow rate of 0.1-3 g / 10 min at 190℃ under a 2.16 kg load and a density of 0.94-0.96 g / cm³. 3 Its melting point is 125-130℃.

[0026] According to the present invention, the ethylene-vinyl acetate copolymer (EVA) has a melt flow rate of 0.1-10 g / 10 min at 190°C under a load of 2.16 kg and a density of 0.92-0.98 g / cm³. 3 The melting point is 90-100℃; preferably, the EVA has a melt flow rate of 0.5-5 g / 10 min at 190℃ under a 2.16 kg load and a density of 0.934-0.97 g / cm³. 3 Its melting point is 90-100℃.

[0027] According to the present invention, the polyolefin elastomer (POE) has a melt flow rate of 0.5-10 g / 10 min at 190°C under a load of 2.16 kg and a density of 0.85-0.92 g / cm³. 3 The melting point is 80-100℃; preferably, the melt flow rate of the POE at 190℃ under a 2.16kg load is 0.5-5g / 10min, and the density is 0.86-0.902g / cm³. 3 Its melting point is 80-95℃.

[0028] In this invention, the performance parameters of the linear low-density polyethylene, the metallocene polyethylene, the polypropylene, the high-density polyethylene, the ethylene-vinyl acetate copolymer (EVA), and the polyolefin elastomer (POE) are limited to the ranges described above, which enables the prepared heavy-duty packaging film to have the advantages of a balance between rigidity and toughness, while maintaining high strength and impact resistance.

[0029] A second aspect of the present invention provides a heavy packaging film made from the aforementioned composition, wherein the heavy packaging film comprises at least an outer layer, a core layer and an inner layer stacked sequentially, wherein the outer layer is obtained by extruding an outer layer material, the core layer is obtained by extruding a core layer material, and the inner layer is obtained by extruding an inner layer material.

[0030] In this invention, the high-impact multilayer heavy-duty packaging film can also be referred to as PP / PE heavy-duty packaging film.

[0031] According to the present invention, the thickness ratio of the outer layer, the core layer and the inner layer is 1:(1-3):1, preferably 1:2:1.

[0032] According to the present invention, the total thickness of the heavy packaging film is 70-170 μm, preferably 100-140 μm.

[0033] According to the present invention, the heavy packaging film is prepared by multilayer co-extrusion; preferably, the heavy packaging film can be three, five, seven, nine or eleven layers; more preferably, it is three layers.

[0034] A third aspect of the present invention provides the application of the aforementioned heavy-duty packaging film in one or more of resin packaging, cement packaging, and rice packaging.

[0035] The present invention will be described in detail below through embodiments.

[0036] In the following examples and comparative examples:

[0037] (1) Puncture resistance test:

[0038] According to the GB / T-10004 testing standard, the sample is cut into pieces with a diameter of 10 cm; the cut sample is fixed and clamped on the sample stage of the puncture resistance tester, and the test needle descends at a speed of 50 mm / min to test the puncture resistance of the film. At least 5 samples are tested for each film.

[0039] (2) Thin film mechanical testing:

[0040] According to the GB / T-1040.3-2006 testing standard, the samples were cut into corresponding tensile strips, and a film tensile test was conducted on a universal tensile testing machine at a speed of 250 mm / min to obtain the yield strength, breaking strength, and elongation at break of the film. Five strips were taken from both the transverse and longitudinal directions, and the average value was calculated.

[0041] (3) Dart impact experiment:

[0042] The dart impact test was conducted according to the method specified in the national standard GB / T 9639.1-2008 "Test methods for impact resistance of plastic films and sheets - free-falling dart method - Part 1: step method".

[0043] (4) Resin source

[0044] LLDPE 7042, with a melt flow index (MFI) of 2 g / 10 min at 190°C under a load of 2.16 kg, has a density (ρ) of 0.924 g / cm³. 3 It has a melting point of 115℃ and is supplied by Shenhua Company.

[0045] HDPE B5703, under a load of 2.16 kg at 190 °C, has an MFI of 0.35 g / 10 min and a density ρ of 0.9600 g / cm³. 3 It has a melting point of 125℃ and was purchased from Yanshan Petrochemical.

[0046] Metallocene polyethylene 8784, with an MFI of 0.80 g / 10 min at 190°C under a load of 2.16 kg, has a density ρ of 0.914 g / cm³. 3 It has a melting point of 115°C and was purchased from ExxonMobil.

[0047] Polypropylene 4220, with an MFI of 0.36 g / 10 min at 230℃ under a load of 2.16 kg, has a density ρ of 0.893 g / cm³. 3 It has a melting point of 140℃ and was purchased from Yanshan Petrochemical.

[0048] EVA, with an MFI of 0.7 g / 10 min at 190°C under a load of 2.16 kg and a density ρ of 0.934 g / cm³, has a molecular weight distribution (MFI) of 0.7 g / 10 min. 3 It has a melting point of 95℃ and was purchased from Formosa Plastics Group in Taiwan (product name: 7140F).

[0049] POE, with an MFI of 1.0 g / 10 min at 190°C under a load of 2.16 kg and a density ρ of 0.902 g / cm³, has a molecular weight distribution (MFI) of 1.0 g / 10 min. 3 It has a melting point of 95°C and was purchased from Dow Chemical PL 1880G.

[0050] Example 1

[0051] This embodiment relates to a heavy-duty packaging film prepared using the composition of the present invention.

[0052] (1) Add 30kg of LLDPE, 50kg of mPE, 10kg of HDPE and 10kg of POE to the inner hopper and the outer hopper respectively, and add 20kg of LLDPE, 60kg of PP and 20kg of mPE to the core hopper (middle hopper).

[0053] (2) After being mixed evenly, the mixture is extruded through three screw extruders (working temperature is 185-200℃), and the outer, middle and inner layers are co-extruded and blown into a cylindrical film through the die head.

[0054] The outer layer of the prepared heavy packaging film has a thickness of 126 μm, where the ratio of inner layer thickness to core layer thickness to outer layer thickness is 1:2:1.

[0055] Examples 2-6

[0056] This embodiment relates to a heavy-duty packaging film prepared using the composition of the present invention.

[0057] The repackaging film was prepared using the same method as in Example 1, except that the components added to the outer hopper, core hopper, and inner hopper, and their contents, are shown in Table 1; the film thickness is shown in Table 2, wherein the ratio of inner layer thickness to core layer thickness to outer layer thickness is 1:2:1.

[0058] Comparative Example 1

[0059] Imported packaging bags are used. These are ExxonMobil resin commercial packaging bags made of polyethylene, with thicknesses as shown in Table 2.

[0060] Comparative Examples 2-4

[0061] The repackaging film was prepared using the same method as in Example 1, except that the components added to the outer hopper, core hopper, and inner hopper, as well as their contents, are shown in Table 1; the resulting thicknesses of each layer of the repackaging film are shown in Table 2.

[0062] Table 1

[0063]

[0064] Note: EVA / POE indicates either EVA or POE.

[0065] Test case

[0066] The films prepared in Examples 1-6 and Comparative Examples 1-4 were subjected to puncture resistance tests, film mechanical tests, and dart impact tests. The test results are shown in Table 2.

[0067] Table 2

[0068]

[0069] Note: The puncture resistance (N) is obtained by testing according to standard GB / T-10004. The puncture resistance (N / mm) is calculated by dividing the puncture resistance (N) by the film thickness.

[0070] As can be seen from the results in Table 2, by blending linear low-density polyethylene, metallocene polyethylene, polypropylene, high-density polyethylene, EVA and POE in a specific component ratio, the prepared heavy-duty packaging film can have the advantage of a balance between rigidity and toughness. While maintaining high strength, it also has excellent toughness, especially improving the impact resistance, i.e., dart impact resistance, of the multilayer heavy-duty packaging film.

[0071] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A heavy-duty packaging film composition, said composition comprising an outer layer material, a core layer material, and an inner layer material, characterized in that: The core material contains linear low-density polyethylene, polypropylene, and optionally metallocene polyethylene; The outer layer material may have the same or different composition as the inner layer material, and each contains linear low-density polyethylene, metallocene polyethylene, high-density polyethylene and ethylene-vinyl acetate copolymer or polyolefin elastomer. Wherein, based on the total weight of the outer layer material, the content of linear low-density polyethylene is 20-60% by weight, the content of metallocene polyethylene is 20-70% by weight, the content of high-density polyethylene is 5-30% by weight, and the content of ethylene-vinyl acetate copolymer or polyolefin elastomer is 5-30% by weight; Wherein, based on the total weight of the inner layer material, the content of linear low-density polyethylene is 20-60% by weight, the content of metallocene polyethylene is 20-70% by weight, the content of high-density polyethylene is 5-30% by weight, and the content of ethylene-vinyl acetate copolymer or polyolefin elastomer is 5-30% by weight; Based on the total weight of the core material, the content of linear low-density polyethylene is 20-80% by weight, the content of polypropylene is 20-80% by weight, and the content of metallocene polyethylene is 0-40% by weight.

2. The composition according to claim 1, wherein, Based on the total weight of the outer layer material, the content of linear low-density polyethylene is 20-50% by weight, the content of metallocene polyethylene is 20-50% by weight, the content of high-density polyethylene is 5-30% by weight, and the content of ethylene-vinyl acetate copolymer or polyolefin elastomer is 5-30% by weight.

3. The composition according to claim 1, wherein, Based on the total weight of the inner layer material, the content of linear low-density polyethylene is 20-50% by weight, the content of metallocene polyethylene is 20-50% by weight, the content of high-density polyethylene is 5-30% by weight, and the content of ethylene-vinyl acetate copolymer or polyolefin elastomer is 5-30% by weight.

4. The composition according to claim 3, wherein, Based on the total weight of the inner layer material, the content of linear low-density polyethylene is 30-40% by weight, the content of metallocene polyethylene is 40-50% by weight, the content of high-density polyethylene is 10-15% by weight, and the content of ethylene-vinyl acetate copolymer or polyolefin elastomer is 10-15% by weight.

5. The composition according to claim 1, wherein, Based on the total weight of the core material, the content of linear low-density polyethylene is 20-70% by weight, the content of polypropylene is 20-70% by weight, and the content of metallocene polyethylene is 0-30% by weight.

6. The composition according to claim 5, wherein, Based on the total weight of the core material, the content of linear low-density polyethylene is 20-40% by weight, the content of polypropylene is 50-60% by weight, and the content of metallocene polyethylene is 10-20% by weight.

7. The composition according to any one of claims 1-6, wherein, The polypropylene is homopolymer polypropylene, binary copolymer polypropylene, or ternary copolymer polypropylene.

8. The composition according to claim 7, wherein, The binary copolymer polypropylene is a copolymer of propylene and ethylene monomers, and the molar content of ethylene monomers in the binary copolymer polypropylene is 2-20 moles.

9. The composition according to claim 7, wherein, The ternary copolymer polypropylene is a ternary random polypropylene composed of propylene, 1-butene, and ethylene.

10. The composition according to claim 7, wherein, The polypropylene has a melt flow rate of 0.3-10 g / 10 min at 230°C under a load of 2.16 kg density, and a density of 0.86-0.96 g / cm³. 3 Its melting point is 130-160℃.

11. The composition according to any one of claims 1-6, wherein, The linear low-density polyethylene has a melt flow rate of 0.3-10 g / 10 min at 190°C under a load of 2.16 kg and a density of 0.91-0.94 g / cm³. 3 Its melting point is 110-125℃.

12. The composition according to any one of claims 1-6, wherein, The metallocene polyethylene has a melt flow rate of 0.1-10 g / 10 min at 190°C under a load of 2.16 kg and a density of 0.85-0.94 g / cm³. 3 Its melting point is 110-125℃.

13. The composition according to any one of claims 1-4, wherein, The high-density polyethylene has a melt flow rate of 0.05-5 g / 10 min at 190°C under a load of 2.16 kg and a density of 0.94-0.96 g / cm³. 3 Its melting point is 125-135℃.

14. The composition according to any one of claims 1-4, wherein, The ethylene-vinyl acetate copolymer has a melt flow rate of 0.1-10 g / 10 min at 190°C under a load of 2.16 kg and a density of 0.92-0.98 g / cm³. 3 Its melting point is 90-100℃; The polyolefin elastomer has a melt flow rate of 0.5-10 g / 10 min at 190°C under a load of 2.16 kg and a density of 0.85-0.92 g / cm³. 3 Its melting point is 80-100℃.

15. A reusable packaging film made from the composition according to any one of claims 1-14, characterized in that, The heavy packaging film comprises at least an outer layer, a core layer, and an inner layer stacked sequentially, wherein the outer layer is obtained by extruding an outer layer material, the core layer is obtained by extruding a core layer material, and the inner layer is obtained by extruding an inner layer material.

16. The repackaging film according to claim 15, wherein, The ratio of the thickness of the outer layer, the thickness of the core layer, and the thickness of the inner layer is 1:(1-3):

1.

17. The repackaging film according to claim 16, wherein, The thickness ratio of the outer layer, the core layer, and the inner layer is 1:2:

1.

18. The repackaging film according to claim 15, wherein, The thickness of the heavy packaging film is 70-170 μm.

19. The repackaging film according to claim 18, wherein, The thickness of the heavy packaging film is 100-140 μm.

20. The repackaging film according to any one of claims 15-19, wherein, The heavy-duty packaging film is produced by multilayer co-extrusion.

21. The repackaging film according to claim 20, wherein, The heavy packaging film has three, five, seven, nine, or eleven layers.

22. The use of a heavy-duty packaging film according to any one of claims 15-21 in one or more of resin packaging, cement packaging and rice packaging.

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