Thin multilayer heavy packaging film composition and thin multilayer heavy packaging film and application thereof

Abstract

The present invention relates to the technical field of packaging materials, and discloses a thin, multi-layer heavy-duty packaging film composition, a thin, multi-layer heavy-duty packaging film, and applications thereof. The composition comprises an outer layer material, a core layer material, and an inner layer material, wherein the core layer material comprises linear low-density polyethylene, metallocene polyethylene, polypropylene, and optionally low-density polyethylene; the outer layer material and the inner layer material may have the same or different components, each comprising linear low-density polyethylene, metallocene polyethylene, high-density polyethylene, and optionally low-density polyethylene. The multi-layer heavy-duty packaging film exhibits excellent tensile strength and puncture resistance.

Description

Technical Field

[0001] The invention relates to the technical field of packaging materials, in particular to a thin multi-layer heavy packaging film composition and a heavy packaging film and applications thereof. Background Art

[0002] FFS film for heavy packaging (FFS is the abbreviation of Form, Fill and Seal) has been rapidly developed due to its advantages such as fast packaging, no pollution, good sealing and printability.

[0003] At present, foreign countries mainly develop high-performance metallocene polyethylene to maintain mechanical properties while achieving thinning to reduce packaging costs.

[0004] On the other hand, polypropylene (PP) has high crystallinity, and its strength, stiffness, and heat resistance are superior to polyethylene, and it has high-temperature creep resistance. Therefore, the development of PP / PE heavy-duty packaging bags is of great significance.

[0005] CN102555392A discloses a PP / PE co-extruded heavy-duty packaging bag film, which has good performance and excellent quality and can better meet the requirements of heavy-duty packaging bags. The film is co-extruded in three layers and blown by the upward blowing method. The components of the three layers of the film are as follows: outer layer: 70%-80% resin B, 20%-30% resin A; middle layer: 40%-60% resin B, 40%-60% resin A; inner layer: 70%-80% resin B, 20%-30% resin A; the ratio of the outer, middle and inner layers to the film thickness is 1:1:1. Resin A is a copolymer of propylene and ethylene monomers, and the molar content of ethylene monomer in the copolymer is 2%-20%; the density of resin A is 0.86g / cm 3 -0.91g / cm 3 , melting point is 135-168 ℃; wherein, resin B is: C6 or C8 metallocene polyethylene; the density of resin B is 0.90g / cm 3 -0.94g / cm 3 , with a melting point of 96°C-128°C. However, the disadvantage is that the polyethylene components used are all metallocene polyethylene, which is difficult to process and has a high material cost.

[0006] Therefore, it is of great significance to research and develop a thin multi-layer heavy packaging film composition and a thin multi-layer heavy packaging film and application thereof. Summary of the Invention

[0007] The purpose of the present invention is to overcome the defects of the existing technology such as thick heavy packaging film, high packaging cost and unstable performance, and to provide a thin multi-layer heavy packaging film composition and a thin multi-layer heavy packaging film and its application, wherein the multi-layer heavy packaging film has good tensile strength and puncture resistance.

[0008] In order to achieve the above object, the first aspect of the present invention provides a thin multi-layer heavy packaging film composition, the composition comprising an outer layer material, a core layer material and an inner layer material, wherein:

[0009] The core layer material contains linear low density polyethylene, metallocene polyethylene, polypropylene and optional low density polyethylene;

[0010] The components of the outer layer material are the same as or different from those of the inner layer material, and each contains linear low-density polyethylene, metallocene polyethylene, high-density polyethylene and optionally low-density polyethylene.

[0011] The second aspect of the present invention provides a thin multi-layer heavy-duty packaging film made from the aforementioned composition, wherein the thin multi-layer heavy-duty packaging film comprises at least an outer layer, a core layer and an inner layer stacked in sequence, wherein the outer layer is extruded from an outer layer material, the core layer is extruded from a core layer material, and the inner layer is extruded from an inner layer material.

[0012] A third aspect of the present invention provides a use of the aforementioned thin multi-layer heavy-duty packaging film in resin packaging and / or rice packaging.

[0013] Through the above technical solution, polypropylene with high crystallinity, high strength and high rigidity is synergistically blended with flexible polyethylene, and combined with a multi-layer blown film process, a thin multi-layer film with good tensile strength and puncture resistance can be prepared. DETAILED DESCRIPTION

[0014] The endpoints of the ranges and any values ​​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 endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0015] The first aspect of the present invention provides a thin multi-layer heavy packaging film composition, the composition comprising an outer layer material, a core layer material and an inner layer material, wherein:

[0016] The core layer material contains linear low density polyethylene, metallocene polyethylene, polypropylene and optional low density polyethylene;

[0017] The components of the outer layer material are the same as or different from those of the inner layer material, and each contains linear low-density polyethylene, metallocene polyethylene, high-density polyethylene and optionally low-density polyethylene.

[0018] According to the present invention, based on the total weight of the outer layer material, the content of the linear low-density polyethylene is 20-60% by weight, the content of the metallocene polyethylene is 30-70% by weight, the content of the high-density polyethylene is 10-30% by weight, and the content of the low-density polyethylene is 0-40% by weight. Preferably, based on the total weight of the outer layer material, the content of the linear low-density polyethylene is 20-60% by weight, the content of the metallocene polyethylene is 30-60% by weight, the content of the high-density polyethylene is 10-30% by weight, and the content of the low-density polyethylene is 0-30% by weight. More preferably, based on the total weight of the outer layer material, the content of the linear low-density polyethylene is 30-50% by weight, the content of the metallocene polyethylene is 40-60% by weight, the content of the high-density polyethylene is 10-20% by weight, and the content of the low-density polyethylene is 0-20% by weight. In the present invention, limiting the content of each component in the outer layer material to the aforementioned ranges has the advantage of maintaining both toughness and rigidity and good processing performance.

[0019] According to the present invention, based on the total weight of the inner layer material, the content of the linear low-density polyethylene is 20-60% by weight, the content of the metallocene polyethylene is 30-70% by weight, the content of the high-density polyethylene is 10-30% by weight, and the content of the low-density polyethylene is 0-40% by weight. Preferably, based on the total weight of the outer layer material, the content of the linear low-density polyethylene is 20-60% by weight, the content of the metallocene polyethylene is 30-60% by weight, the content of the high-density polyethylene is 10-30% by weight, and the content of the low-density polyethylene is 0-30% by weight. More preferably, based on the total weight of the outer layer material, the content of the linear low-density polyethylene is 30-50% by weight, the content of the metallocene polyethylene is 40-60% by weight, the content of the high-density polyethylene is 10-20% by weight, and the content of the low-density polyethylene is 0-20% by weight. In the present invention, by limiting the content of each component in the inner layer material to the aforementioned ranges, both toughness and rigidity can be maintained, and processing performance is good.

[0020] According to the present invention, based on the total weight of the core material, the content of the linear low-density polyethylene is 20-80% by weight, the content of the metallocene polyethylene is 10-60% by weight, the content of the polypropylene is 10-70% by weight, and the content of the low-density polyethylene is 0-40% by weight. Preferably, based on the total weight of the core material, the content of the linear low-density polyethylene is 20-80% by weight, the content of the metallocene polyethylene is 10-50% by weight, the content of the polypropylene is 10-60% by weight, and the content of the low-density polyethylene is 0-30% by weight. More preferably, based on the total weight of the core material, the content of the linear low-density polyethylene is 20-30% by weight, the content of the metallocene polyethylene is 20-50% by weight, the content of the polypropylene is 20-60% by weight, and the content of the low-density polyethylene is 0-20% by weight. In the present invention, the content of each component in the core material is limited to the aforementioned range, which has the advantage of being able to be regulated while maintaining toughness and rigidity, and having good processing performance.

[0021] 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 monomer in the binary copolymer is 2-20 mol%, preferably 5-15 mol%.

[0022] According to the present invention, the terpolymer polypropylene is a terpolymer random polypropylene of propylene, 1-butene and ethylene.

[0023] 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 and a density of 0.86-0.96 g / cm 3 , melting point is 130-160 ℃; preferably, the melt flow rate of the polypropylene at 230 ℃ under a load of 2.16 kg is 0.35-5 g / 10 min, and the density is 0.86-0.94 g / cm 3 , melting point is 130-150℃.

[0024] According to the present invention, the linear low-density polyethylene has a melt flow rate of 0.3-10.0 g / 10 min at 190° C. under a load of 2.16 kg and a density of 0.91-0.94 g / cm 3 , melting point is 110-125 ℃; preferably, the linear low density polyethylene has a melt flow rate of 0.3-5.0 g / 10 min at 190 ℃ under a load of 2.16 kg and a density of 0.91-0.92 g / cm 3 , melting point is 110-120℃.

[0025] According to the present invention, the melt flow rate of the metallocene polyethylene at 190°C under a load of 2.16 kg is 0.1-10 g / 10 min, and the density is 0.85-0.94 g / cm 3 , melting point is 110-125 ℃; preferably, the melt flow rate of the metallocene polyethylene at 190 ℃ under a load of 2.16 kg is 0.1-5 g / 10 min, and the density is 0.85-0.92 g / cm 3 , melting point is 110-120℃.

[0026] 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 / cm 3 , melting point is 125-135 ℃; preferably, the melt flow rate of the high-density polyethylene at 190 ℃ under a load of 2.16 kg is 0.1-3 g / 10 min, and the density is 0.94-0.96 g / cm 3 , melting point is 125-130℃.

[0027] According to the present invention, the low-density polyethylene (LDPE) has a melt flow rate of 1-10 g / 10 min at 190° C. under a load of 2.16 kg and a density of 0.910-0.935 g / cm 3 , melting point is 105-115 ℃; preferably, the linear low density polyethylene has a melt flow rate of 1-5g / 10min at 190 ℃ under a load of 2.16kg and a density of 0.910-0.925g / cm 3 , melting point is 105-110℃.

[0028] In the present invention, the performance parameters of the polypropylene, the linear low-density polyethylene, the metallocene polyethylene, the high-density polyethylene and the low-density polyethylene are limited to the aforementioned ranges, so that a thin multilayer film with good tensile strength and puncture resistance can be prepared.

[0029] The second aspect of the present invention provides a thin multi-layer heavy-duty packaging film made from the aforementioned composition, wherein the thin multi-layer heavy-duty packaging film comprises at least an outer layer, a core layer and an inner layer stacked in sequence, wherein the outer layer is extruded from an outer layer material, the core layer is extruded from a core layer material, and the inner layer is extruded from an inner layer material.

[0030] In the present invention, the thin multi-layer heavy packaging film may also be referred to as a PP / PE heavy packaging film.

[0031] According to the present invention, 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, preferably 1:2:1.

[0032] According to the present invention, the total thickness of the thin multi-layer heavy packaging film is 70-170 μm, preferably 100-140 μm, and more preferably 110-130 μm.

[0033] According to the present invention, the thin multi-layer heavy packaging film is produced by a multi-layer co-extrusion method; preferably, the thin multi-layer heavy packaging film can be three-layer, five-layer, seven-layer, nine-layer or eleven-layer; more preferably three-layer.

[0034] A third aspect of the present invention provides a use of the aforementioned thin multi-layer heavy packaging film in resin and / or rice packaging.

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

[0036] In the following examples and comparative examples:

[0037] (1) Puncture resistance test:

[0038] According to the GB / T-10004 test standard, cut the sample into 10cm diameter pieces. Clamp the cut sample on the sample table of the puncture resistance tester. The test needle descends at a speed of 50mm / min to measure the film's puncture resistance. At least five samples are tested for each film.

[0039] (2) Film mechanical testing:

[0040] According to the GB / T-1040.3-2006 test standard, samples were cut into corresponding tensile strips and subjected to film tensile testing on a universal tensile machine at a test speed of 250mm / min to determine the film's yield strength, breaking strength, and elongation at break. Five strips were taken in both the horizontal and vertical directions, and the average value was calculated.

[0041] (3) Resin source

[0042] LDPE 2426H, melt flow rate (melt index) MFI = 1.9 g / 10 min at 190 ° C under a load of 2.16 kg, density ρ is 0.925 g / cm 3 , melting point 105℃, provided by Shenhua Company.

[0043] LLDPE 7042 (melt index MFI = 2 g / 10 min at 190 ° C under a load of 2.16 kg, density ρ is 0.924 g / cm 3 ), melting point 115°C, provided by Shenhua Company.

[0044] HDPE B5703, MFI = 0.35 g / 10 min at 190°C under a load of 2.16 kg; density ρ = 0.9600 g / cm 3 , melting point 125℃, purchased from Yanshan Petrochemical.

[0045] Metallocene polyethylene 8784, MFI = 0.80 g / 10 min at 190 ° C under a load of 2.16 kg, density ρ = 0.914 g / cm 3 , melting point 115 ° C, purchased from ExxonMobil.

[0046] Polypropylene 4220, MFI = 0.36 g / 10 min at 230°C under a load of 2.16 kg, density ρ = 0.893 g / cm 3 , melting point is 140℃, purchased from Yanshan Petrochemical.

[0047] Example 1

[0048] This embodiment is about a thin multi-layer heavy packaging film (PP / PE heavy packaging film) prepared by using the composition of the present invention.

[0049] (1) Add 30 kg of LLDPE, 10 kg of HDPE and 60 kg of mPE to the inner and outer hoppers respectively, and add 30 kg of LLDPE, 50 kg of PP and 20 kg of mPE to the core hopper (middle hopper);

[0050] (2) After being evenly mixed, the film 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.

[0051] Results The thickness of the prepared heavy packaging film was 120 μm, wherein the ratio of inner layer thickness: core layer thickness: outer layer thickness was 1:2:1.

[0052] Examples 2-6

[0053] This embodiment is about a thin multi-layer heavy-duty packaging film prepared using the composition of the present invention.

[0054] A thin multi-layer heavy-duty packaging film was prepared in the same manner as in Example 1, except that the components added to the outer layer hopper, the core layer hopper, and the inner layer hopper and the component contents were as shown in Table 1. As a result, the thickness of each layer of the prepared thin multi-layer heavy-duty packaging film was as shown in Table 2, wherein the thickness of the inner layer: the thickness of the core layer: the thickness of the outer layer = 1:2:1.

[0055] Comparative Example 1

[0056] Domestic heavy packaging bags are used, which are Shenhua Yulin polyolefin packaging bags, model 2426H, and made of polyethylene.

[0057] Comparative Examples 2-4

[0058] A thin multi-layer heavy-duty packaging film was prepared in the same manner as in Example 1, except that the components added to the outer layer hopper, the core layer hopper, and the inner layer hopper and the component contents were as shown in Table 1. As a result, the thickness of each layer of the prepared thin multi-layer heavy-duty packaging film was as shown in Table 2, wherein the thickness of the inner layer: the thickness of the core layer: the thickness of the outer layer = 1:2:1.

[0059] Table 1

[0060]

[0061] Test Case

[0062] The films prepared in Examples 1-6 and Comparative Examples 1-4 were subjected to puncture resistance test, film mechanical test and dart impact test. The test results are shown in Table 2.

[0063] Table 2

[0064]

[0065] Note: Puncture resistance (N) is tested according to standard GB / T-10004, and puncture resistance (N / mm) is calculated by dividing puncture resistance (N) by film thickness.

[0066] The results in Table 2 show that, by blending linear low-density polyethylene, metallocene polyethylene, polypropylene, high-density polyethylene and optional low-density polyethylene at specific component ratios in Examples 1-6 of the present invention, the prepared thin multi-layer heavy-duty packaging films have an excellent balance of rigidity and toughness, and have high yield strength, tensile strength and puncture resistance.

[0067] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A thin multi-layer heavy-duty packaging film composition comprising an outer layer material, a core layer material, and an inner layer material, characterized in that: The core layer material contains linear low-density polyethylene, metallocene polyethylene, polypropylene and optional low-density polyethylene; wherein, based on the total weight of the core layer material, the content of the linear low-density polyethylene is 20-80% by weight, the content of the metallocene polyethylene is 10-60% by weight, the content of the polypropylene is 10-70% by weight, and the content of the low-density polyethylene is 0-40%; The components of the outer layer material are the same as or different from those of the inner layer material, and each contains linear low-density polyethylene, metallocene polyethylene, high-density polyethylene, and optional low-density polyethylene; wherein, based on the total weight of the outer layer material, the content of the linear low-density polyethylene is 20-60% by weight, the content of the metallocene polyethylene is 30-70% by weight, the content of the high-density polyethylene is 10-30% by weight, and the content of the low-density polyethylene is 0-40%; based on the total weight of the inner layer material, the content of the linear low-density polyethylene is 20-60% by weight, the content of the metallocene polyethylene is 30-70% by weight, the content of the high-density polyethylene is 10-30% by weight, and the content of the low-density polyethylene is 0-40%; The thickness ratio of the outer layer obtained by extruding the outer layer material, the thickness of the core layer obtained by extruding the core layer material, and the thickness of the inner layer obtained by extruding the inner layer material is 1:(1-3):

1.

2. The composition according to claim 1, wherein The outer layer material contains linear low-density polyethylene, metallocene polyethylene, high-density polyethylene and optional low-density polyethylene, and based on the total weight of the outer layer material, the content of the linear low-density polyethylene is 20-60% by weight, the content of the metallocene polyethylene is 30-60% by weight, the content of the high-density polyethylene is 10-30% by weight, and the content of the low-density polyethylene is 0-30%.

3. The composition according to claim 2, wherein The outer layer material contains linear low-density polyethylene, metallocene polyethylene, high-density polyethylene and optional low-density polyethylene, and based on the total weight of the outer layer material, the content of the linear low-density polyethylene is 30-50% by weight, the content of the metallocene polyethylene is 40-60% by weight, the content of the high-density polyethylene is 10-20% by weight, and the content of the low-density polyethylene is 0-20%.

4. The composition according to claim 1, wherein The inner layer material contains linear low-density polyethylene, metallocene polyethylene, high-density polyethylene and optional low-density polyethylene, and based on the total weight of the inner layer material, the content of the linear low-density polyethylene is 20-60% by weight, the content of the metallocene polyethylene is 30-60% by weight, the content of the high-density polyethylene is 10-30% by weight, and the content of the low-density polyethylene is 0-30%.

5. The composition according to claim 4, wherein The inner layer material contains linear low-density polyethylene, metallocene polyethylene, high-density polyethylene and optional low-density polyethylene, and based on the total weight of the inner layer material, the content of the linear low-density polyethylene is 30-50% by weight, the content of the metallocene polyethylene is 40-60% by weight, the content of the high-density polyethylene is 10-20% by weight, and the content of the low-density polyethylene is 0-20%.

6. The composition according to claim 1, wherein The core layer material contains linear low-density polyethylene, metallocene polyethylene, polypropylene and optional low-density polyethylene, and based on the total weight of the core layer material, the content of the linear low-density polyethylene is 20-80% by weight, the content of the metallocene polyethylene is 10-50% by weight, the content of the polypropylene is 10-60% by weight, and the content of the low-density polyethylene is 0-30%.

7. The composition according to claim 6, wherein The core layer material contains linear low-density polyethylene, metallocene polyethylene, polypropylene and optional low-density polyethylene, and based on the total weight of the core layer material, the content of the linear low-density polyethylene is 20-30% by weight, the content of the metallocene polyethylene is 20-50% by weight, the content of the polypropylene is 20-60% by weight, and the content of the low-density polyethylene is 0-20%.

8. The composition according to claim 1 or 7, wherein The polypropylene is a homopolymer polypropylene, a binary copolymer polypropylene or a ternary copolymer polypropylene; And / or, the polypropylene has a melt flow rate of 0.3-10 g / 10 min at 230° C. under a load of 2.16 kg and a density of 0.86-0.96 g / cm 3 , melting point is 130-160℃.

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

10. The composition according to claim 8, wherein The terpolymer polypropylene is a terpolymer random polypropylene of propylene, 1-butene and ethylene.

11. The composition according to any one of claims 1 to 7, 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 / cm 3 , melting point is 110-125℃.

12. The composition according to any one of claims 1 to 7, 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 / cm 3 , melting point is 110-125℃.

13. The composition according to any one of claims 1 to 5, 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 / cm 3 , melting point is 125-135℃.

14. The composition according to any one of claims 1 to 7, wherein The low-density polyethylene has a melt flow rate of 1-10 g / 10 min at 190° C. under a load of 2.16 kg and a density of 0.910-0.935 g / cm 3 , melting point is 105-115℃.

15. A thin multi-layer heavy-duty packaging film made from the composition according to any one of claims 1 to 14, characterized in that: The thin multi-layer heavy packaging film comprises at least an outer layer, a core layer and an inner layer stacked in sequence, wherein the outer layer is extruded from an outer layer material, the core layer is extruded from a core layer material, and the inner layer is extruded from an inner layer material; wherein the thickness ratio of the outer layer, the thickness of the core layer and the thickness of the inner layer is 1:(1-3):

1.

16. The thin multi-layer heavy packaging film according to claim 15, wherein: The thickness ratio of the outer layer, the core layer and the inner layer is 1:2:

1.

17. The thin multi-layer heavy packaging film according to claim 15, wherein: The thickness of the thin multi-layer heavy packaging film is 70-170 μm.

18. The thin multi-layer heavy packaging film according to claim 16, wherein: The thickness of the thin multi-layer heavy packaging film is 100-140 μm.

19. The thin multi-layer heavy packaging film according to any one of claims 15 to 18, wherein: The thin multi-layer heavy packaging film is produced by a multi-layer co-extrusion method.

20. Use of the thin multi-layer heavy-duty packaging film according to any one of claims 15 to 19 in resin packaging and / or rice packaging.

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