Modified pe film, preparation method therefor, and use thereof

Abstract

The present invention relates to the technical field of high polymer materials. Disclosed are a modified PE film, a preparation method therefor, and a use thereof. The modified PE film comprises, in sequence, a first polyethylene (PE) layer, a first metallocene polyethylene layer, a first TiC bonding layer, an ethylene-vinyl alcohol copolymer barrier layer, a second TiC bonding layer, a second metallocene polyethylene layer, and a second polyethylene (PE) layer. The mass content of the first polyethylene (PE) layer and the mass content of the second polyethylene (PE) layer are each 20%-30% of the mass of the modified PE film; the mass content of the first metallocene polyethylene layer and the mass content of the second metallocene polyethylene layer are each 8%-12% of the mass of the modified PE film; the mass content of the first TiC bonding layer and the mass content of the second TiC bonding layer are each 5%-10% of the mass of the modified PE film; and the mass content of the ethylene-vinyl alcohol copolymer barrier layer is 15%-25% of the modified PE film. The modified PE film has high overall puncture resistance and good barrier properties, thus enhancing leakage prevention while ensuring high toughness.

Description

A modified PE film and its preparation method and application Technical Field

[0001] The present invention relates to the technical field of polymer materials, and more particularly to a modified PE film, a preparation method thereof, and applications thereof. Background Art

[0002] Currently, PE water supply pipes produced and used on the market are generally single-layer structures made of high-density polyethylene, which is extruded and cooled into shape by equipment, and then connected by heat-melt welding. Their high toughness and ability to withstand certain impacts make them the primary pipe material used for water supply in major corporate projects. However, these PE pipes have low mechanical strength, poor puncture resistance and leak-proofing, and a short service life. In complex environments or under certain objective factors, such as prolonged use, high operating temperatures, or the presence of corrosive elements in liquids, the pipes are prone to rupture, resulting in leakage, causing varying degrees of impact and loss for users.

[0003] Prior art discloses a modified polyolefin composite film composition and modified polyolefin composite film, as well as preparation methods and applications thereof. The composition comprises a first film layer, an intermediate film layer, and a third film layer, wherein the third film layer comprises a PE corona layer material, a barrier layer material, and a PE heat-seal layer material. The first film layer and the intermediate film material each comprise one or more of C4-C8 polyethylene, homopolypropylene, dipolymer polypropylene, and terpolymer polypropylene; and the barrier layer material comprises ethylene-vinyl alcohol copolymer and / or thermoplastic polyvinyl alcohol. This prior art also improves the puncture resistance of the modified polyolefin composite film, but the maximum puncture resistance force is only 13.2N, indicating that further improvement is needed.

[0004] Summary of the Invention

[0005] In order to overcome the defects and shortcomings of the existing PE water pipes, the present invention provides a modified PE film. The modified PE film has a layered structure. By controlling the components of each layer and the mass content of each layer, the puncture resistance of the modified PE film is synergistically improved, and it also has good barrier properties and leak-proof effects.

[0006] Another object of the present invention is to provide a method for preparing a modified PE film.

[0007] Another object of the present invention is to provide an application of a modified PE film in pipe preparation.

[0008] Another object of the present invention is to provide a PE water supply pipe.

[0009] Another object of the present invention is to provide a method for preparing the above-mentioned PE water supply pipe.

[0010] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0011] A modified PE film, comprising a seven-layer structure, comprising, in order, a first polyethylene (PE) layer, a first metallocene polyethylene (PE) layer, a first TiC adhesive layer, an ethylene-vinyl alcohol copolymer barrier layer, a second TiC adhesive layer, a second metallocene polyethylene (PE) layer, and a second polyethylene (PE) layer;

[0012] The mass content of the first polyethylene PE layer and the second polyethylene PE layer is 20% to 30% of the mass of the modified PE film;

[0013] The mass content of the first metallocene polyethylene layer and the second metallocene polyethylene layer is 8% to 12% of the mass of the modified PE film;

[0014] The mass content of the first TiC bonding layer and the second TiC bonding layer is 5% to 10% of the mass of the modified PE film;

[0015] The mass content of the ethylene-vinyl alcohol copolymer barrier layer is 15% to 25% of the modified PE film.

[0016] It should be noted that:

[0017] The modified PE film of the present invention comprises a multilayer structure, wherein the ethylene-vinyl alcohol barrier layer as the middlemost layer can improve the barrier and protective properties of the modified PE film. Since ethylene and vinyl acetate are copolymerized and then the copolymer is hydrolyzed to obtain ethylene-vinyl alcohol, the film still retains a high barrier effect and has significant improvements in moisture resistance and processing properties.

[0018] The outermost polyethylene (PE) layer and the penultimate metallocene polyethylene (MP) layer significantly enhance the modified PE film's tensile strength, adhesion, and puncture resistance. MPE is produced using metallocenes as polymerization catalysts, and therefore exhibits significant performance differences from PE produced using traditional Ziegler-Natta catalysts. MPE is the fastest-growing and most mature of these, boasting a lower melting point and a distinct melting zone, and significantly outperforming traditional polyethylene in toughness, transparency, hot tack, heat-sealing temperature, and low odor. Therefore, with the foundation of the MPE layer and the excellent barrier and protective properties of the EVA barrier layer, the modified PE film also exhibits significant improvements in anti-fouling properties.

[0019] The mass content of each of the above layers has a significant impact on the improvement of overall performance. Excessive or insufficient mass content of each layer will affect the synergistic effect of the layers, thereby affecting the overall puncture resistance, barrier properties, and leakproofness of the modified PE film, and the overall product effect will not reach the optimal state. Excessive or insufficient mass content of each layer will also affect the overall mechanical properties of the modified PE film.

[0020] Under the synergistic effect of the various layers of the present invention, the overall puncture resistance of the modified PE film can reach 23.5-25N. The water vapor transmission rate can well characterize the barrier property of the modified PE film, and the water vapor transmission rate can be reduced to 3.8g / m 2 *24h or less, while ensuring high toughness, the anti-leakage effect is improved, and the pipe body is not broken when subjected to 80℃ hot water hydraulic test for 165H and 1000H under fixed pressure.

[0021] In a specific embodiment, the mass content of the first polyethylene PE layer and the second polyethylene PE layer is 24% of the mass of the modified PE film.

[0022] In a specific embodiment, the mass content of the first metallocene polyethylene layer and the second metallocene polyethylene layer is 10% of the mass of the modified PE film.

[0023] In a specific embodiment, the mass content of the ethylene-vinyl alcohol copolymer barrier layer is 20% of the modified PE film.

[0024] In a specific embodiment, the mass content of the first TiC adhesive layer and the second TiC adhesive layer is 6% of the mass of the modified PE film.

[0025] In a specific embodiment, the number average molecular weight of the polyethylene of the polyethylene PE layer of the present invention is selected to be 10,000 to 100,000, the melt mass flow rate is selected to be 1.8-2.2 g / 10 min, and the test standard is ISO 1133-1-2011, 230° C., and 2.16 kg load.

[0026] In a specific embodiment, the metallocene polyethylene of the metallocene polyethylene layer of the present invention is selected to have a melt mass flow rate greater than or equal to 1.6 g / 10 min, tested according to ISO 1133-1-2011, 230° C., and a load of 2.16 kg.

[0027] In a specific embodiment, the melt mass flow rate of the ethylene-vinyl alcohol copolymer of the ethylene-vinyl alcohol copolymer barrier layer of the present invention is selected to be 1.8 to 2.2 g / 10 min, and the test standard is ISO 1133-1-2011, 230° C., and 2.16 kg load.

[0028] In actual production, the higher the molecular weight of polyethylene, the more difficult it is to process. Excessive difficulty will lead to more stringent requirements on production operations and other details.

[0029] The melt mass flow rate of each layer of the above-mentioned film (including the composite pipe) is controlled within a certain range to prevent sediment accumulation and organic matter adhesion caused by excessively high melt mass flow rate, which can reduce the breeding of aquatic organisms and bacteria. While preventing pipeline corrosion and scaling to a great extent, it also effectively reduces pipeline friction and improves flow conduction capacity, thereby ensuring pipeline stability and enhancing puncture resistance, barrier properties and leak-proof effects.

[0030] The present invention provides a method for preparing a modified PE film, comprising the following steps:

[0031] Polyethylene, metallocene polyethylene, TiC and ethylene-vinyl alcohol copolymer are extruded through a co-extruder, extruded through a multi-channel composite die head, and cooled and shaped to obtain a modified PE film.

[0032] In a specific embodiment, the extrusion temperature of co-extrusion is about 200-220°C. Too high or too low a temperature will affect the uniformity and completeness of the plasticization between molecules. The extrusion speed depends on the type of equipment. During the production process, the main operator adjusts it according to the actual situation. It is generally recommended to be 1.2-1.8m / min.

[0033] The present invention also protects the use of a modified PE film in the preparation of pipes.

[0034] The modified PE film of the present invention has excellent puncture resistance and barrier properties, can protect pipes and prevent them from rupturing, and has excellent leak-proof effect, thereby improving the practicality of the pipes.

[0035] The present invention particularly protects a PE water supply pipe comprising a modified PE film.

[0036] The above-mentioned PE water supply pipe contains the modified PE film of the present invention, has excellent puncture resistance and leakage prevention effects, high toughness, is not prone to leakage due to rupture even after long-term use or increase of corrosive elements in the liquid, and has a long service life.

[0037] Specifically, the PE water supply pipe includes a three-layer structure, the middle layer is a modified PE film, and the inner and outer layers are both PE layers.

[0038] The modified PE film described in this invention, applied to the surface of a water supply pipe as an intermediate layer, effectively prevents liquid from leaking through cracks in the inner layer, enhancing puncture resistance and leak prevention, and increasing the product's practicality and longevity. A protective outer layer of a strong PE material protects the puncture-resistant and leak-proof film and inner layer, preventing damage to the pipe from external factors and further extending its service life.

[0039] Specifically, the PE of the inner layer and the outer layer is HDPE.

[0040] Specifically, the mass ratio of the inner layer, middle layer, and outer layer is 3:5:2. This product doesn't strictly stipulate a fixed mass ratio for the inner, middle, and outer layers; only a suggested range is provided. The inner and outer PE layers primarily serve as a wrapping layer, and production has certain requirements for appearance. The middle layer is the core component that provides enhanced performance.

[0041] The present invention specifically protects a method for preparing the above-mentioned PE water supply pipe, comprising the following steps:

[0042] First, the inner layer of HDPE core pipe is extruded through an extruder and cooled to shape; the core pipe is heated to a certain temperature through a hot drying device, and a flowing film is extruded through a co-extruder to cover the outer wall of the core pipe to form a protective film; then a layer of HDPE material is attached to the outer layer of the protective film through an extruder; and the PE water supply pipe is produced by cooling and shaping through a cooling and shaping device.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] The modified PE film of the present invention has a layered structure, wherein the ethylene-vinyl alcohol barrier layer as the middle layer can improve the barrier and protection properties of the modified PE film. Since ethylene and vinyl acetate are copolymerized and the copolymer is hydrolyzed to obtain ethylene-vinyl alcohol, it still retains a high barrier effect. The outermost polyethylene PE layer and the penultimate metallocene polyethylene layer can significantly improve the tensile strength and puncture resistance of the modified PE film, and ultimately the overall puncture resistance of the modified PE film can reach 23.5-25N. The water vapor transmission rate can well characterize the barrier properties of the modified PE film, and the water vapor transmission rate can reach 3.8g / m 2 *24h or less, while ensuring high toughness, the anti-leakage effect is improved, and the pipe body is not broken when subjected to 80℃ hot water hydraulic test for 165H and 1000H under fixed pressure.

[0045] The modified PE film of the present invention is particularly suitable for the field of pipes, especially for preparing PE water supply pipes. It can improve the puncture resistance and leakage prevention effects of PE water supply pipes, ensure their toughness, and improve the practicality and service life of the products. DETAILED DESCRIPTION

[0046] The raw materials used in the following examples and comparative examples of the present invention are described as follows:

[0047] Polyethylene (PE): number average molecular weight of 56,200, melt mass flow rate of 1.86 g / 10 min, South Korea LG, SP980;

[0048] Metallocene polyethylene-1: melt mass flow rate is 1.767 g / 10 min, Qilu Petrochemical QHM32F;

[0049] Metallocene polyethylene-2: melt mass flow rate of 1.58 g / 10 min, Dongguan Renhong SP1520;

[0050] Ethylene vinyl alcohol copolymer-1: melt mass flow rate is 1.93 g / 10 min, Hubei Nona 25067-34-9;

[0051] Ethylene vinyl alcohol copolymer-2: melt mass flow rate is 1.65g / 10min, Dongguan Baojia H171B;

[0052] TiC: Jiangxi Ketai, KT2023;

[0053] High-density polyethylene (HDPE): Borouge in the Middle East, HE3490LSH;

[0054] The present invention will be further described below in conjunction with specific embodiments, but the examples do not limit the present invention in any form. Unless otherwise stated, the raw materials and reagents used in the examples of the present invention are conventionally purchased raw materials and reagents.

[0055] Example 1

[0056] A modified PE film, comprising a seven-layer structure, comprising a polyethylene (PE) layer, a metallocene polyethylene (MP) layer, a TiC adhesive layer, an ethylene-vinyl alcohol (EVA) copolymer barrier layer, a TiC adhesive layer, a metallocene polyethylene (MP) layer, and a polyethylene (PE) layer.

[0057] The mass content of the first polyethylene PE layer and the second polyethylene PE layer is 24% of the mass of the modified PE film;

[0058] The mass content of the first metallocene polyethylene layer and the second metallocene polyethylene layer is 10% of the mass of the modified PE film, and the metallocene polyethylene is metallocene polyethylene-1;

[0059] The mass content of the first TiC bonding layer and the second TiC bonding layer is 6% of the mass of the modified PE film;

[0060] The mass content of the ethylene-vinyl alcohol copolymer barrier layer is 20% of the modified PE film, and the ethylene-vinyl alcohol copolymer is ethylene-vinyl alcohol copolymer-1.

[0061] The preparation method of the modified PE film can be referred to as follows:

[0062] Polyethylene, metallocene polyethylene, TiC and ethylene-vinyl alcohol copolymer are extruded through a co-extruder, extruded through a multi-channel composite die head, and cooled and shaped to obtain a modified PE film.

[0063] Examples 2-3

[0064] A modified PE film, the structure of the modified PE film is the same as that of Example 1, and the differences are shown in Table 1.

[0065] Table 1. Mass content of different layers relative to the film in the modified PE film (%)

[0066] The preparation methods of the modified PE films of Examples 2 to 3 are the same as those of Example 1.

[0067] Example 4

[0068] A modified PE film, wherein the structure of the modified PE film is the same as that of Example 1, except that the metallocene polyethylene is metallocene polyethylene-2.

[0069] The preparation method of the modified PE film is the same as that in Example 1.

[0070] Example 5

[0071] A modified PE film, wherein the modified PE film structure is the same as that of Example 1, except that the ethylene-vinyl alcohol copolymer is ethylene-vinyl alcohol copolymer-2.

[0072] The preparation method of the modified PE film is the same as that in Example 1.

[0073] Examples 6 to 10

[0074] A PE water supply pipe comprises a three-layer structure, an inner layer, a middle layer and an outer layer. The mass ratio of the inner layer, the middle layer and the outer layer is 3:5:2. The middle layer is the modified PE film of Examples 1 to 5. The inner and outer layers are both PE layers. The PE of the inner and outer layers is HDPE.

[0075] The preparation method of PE water supply pipe is as follows:

[0076] First, the inner layer of HDPE core pipe is extruded through an extruder and cooled to shape; the core pipe is heated to a certain temperature through a hot drying device, and a flowing film is extruded through a co-extruder to cover the outer wall of the core pipe to form a protective film; then a layer of HDPE material is attached to the outer layer of the protective film through an extruder; and the final reinforced water supply pipe is produced by cooling and shaping through a cooling and shaping device.

[0077] Among them, Example 6 corresponds to the modified PE film of Example 1, Example 7 corresponds to the modified PE film of Example 2, and so on.

[0078] Comparative Example 1

[0079] A modified PE film, comprising a five-layer structure, comprising a first polyethylene PE layer, a first TiC adhesive layer, an ethylene-vinyl alcohol copolymer barrier layer, a second TiC adhesive layer, and a second polyethylene PE layer.

[0080] The mass content of the first polyethylene PE layer and the second polyethylene PE layer is 34% of the mass of the modified PE film;

[0081] The mass content of the first TiC bonding layer and the second TiC bonding layer is 6% of the mass of the modified PE film;

[0082] The mass content of the ethylene-vinyl alcohol copolymer barrier layer is 20% of the modified PE film, and the ethylene-vinyl alcohol copolymer is ethylene-vinyl alcohol copolymer-1.

[0083] The preparation method of the modified PE film is the same as that in Example 1.

[0084] Comparative Example 2

[0085] A modified PE film, comprising a seven-layer structure, comprising a polyethylene (PE) layer, a metallocene polyethylene (MP) layer, a TiC adhesive layer, an ethylene-vinyl alcohol (EVA) copolymer barrier layer, a TiC adhesive layer, a metallocene polyethylene (MP) layer, and a polyethylene (PE) layer.

[0086] The mass content of the first polyethylene PE layer and the second polyethylene PE layer is 28% of the mass of the modified PE film;

[0087] The mass content of the first metallocene polyethylene layer and the second metallocene polyethylene layer is 6% of the mass of the modified PE film, and the metallocene polyethylene is metallocene polyethylene-1;

[0088] The mass content of the first TiC bonding layer and the second TiC bonding layer is 6% of the mass of the modified PE film;

[0089] The mass content of the ethylene-vinyl alcohol copolymer barrier layer is 20% of the modified PE film, and the ethylene-vinyl alcohol copolymer is ethylene-vinyl alcohol copolymer-1.

[0090] The preparation method of the modified PE film is the same as that in Example 1.

[0091] Comparative Example 3

[0092] A modified PE film, comprising a seven-layer structure, comprising a polyethylene (PE) layer, a metallocene polyethylene (MP) layer, a TiC adhesive layer, an ethylene-vinyl alcohol (EVA) copolymer barrier layer, a TiC adhesive layer, a metallocene polyethylene (MP) layer, and a polyethylene (PE) layer.

[0093] The mass content of the first polyethylene PE layer and the second polyethylene PE layer is 20% of the mass of the modified PE film;

[0094] The mass content of the first metallocene polyethylene layer and the second metallocene polyethylene layer is 18% of the mass of the modified PE film, and the metallocene polyethylene is metallocene polyethylene-1;

[0095] The mass content of the first TiC bonding layer and the second TiC bonding layer is 6% of the mass of the modified PE film;

[0096] The mass content of the ethylene-vinyl alcohol copolymer barrier layer is 12% of the modified PE film, and the ethylene-vinyl alcohol copolymer is ethylene-vinyl alcohol copolymer-1.

[0097] The preparation method of the modified PE film is the same as that in Example 1.

[0098] Comparative Example 4

[0099] A modified PE film, comprising a seven-layer structure, comprising a polyethylene (PE) layer, a metallocene polyethylene (MP) layer, a TiC adhesive layer, an ethylene-vinyl alcohol (EVA) copolymer barrier layer, a TiC adhesive layer, a metallocene polyethylene (MP) layer, and a polyethylene (PE) layer.

[0100] The mass content of the first polyethylene PE layer and the second polyethylene PE layer is 24% of the mass of the modified PE film;

[0101] The mass content of the first metallocene polyethylene layer and the second metallocene polyethylene layer is 7% of the mass of the modified PE film, and the metallocene polyethylene is metallocene polyethylene-1;

[0102] The mass content of the first TiC bonding layer and the second TiC bonding layer is 6% of the mass of the modified PE film;

[0103] The mass content of the ethylene-vinyl alcohol copolymer barrier layer is 26% of the modified PE film, and the ethylene-vinyl alcohol copolymer is ethylene-vinyl alcohol copolymer-1.

[0104] The preparation method of the modified PE film is the same as that in Example 1.

[0105] Result detection

[0106] The specific test methods are as follows:

[0107] (1) Puncture resistance test

[0108] GB / T37841-2019 Test method for puncture resistance of plastic film and sheeting.

[0109] (2) Water vapor transmission rate test

[0110] GB1037-1988 Test method for water vapor permeability of plastic film and sheet (cup method).

[0111] GB / T 26253-2010 Plastic film and sheeting - Determination of water vapor transmission rate - Infrared detector

[0112] GB / T 30412-2013 Plastic film and sheeting - Determination of water vapor transmission rate - Humidity sensor method

[0113] (3) Leakage prevention effect

[0114] GB / T 13663.2-2018 “Polyethylene (PE) piping systems for water supply – Part 2: Pipes”.

[0115] See Table 2 for the results.

[0116] Table 2. Performance test data of puncture-resistant and leak-proof membrane

[0117] Among them, the greater the puncture resistance value, the better the puncture resistance of the modified PE film of the present invention. The water vapor permeability can well characterize the barrier property of the modified PE film. The lower the water vapor permeability value, the better the barrier property of the modified PE film. The leakage resistance test under 80°C hydraulic pressure shows that the modified PE film of the present invention can achieve a leakage resistance effect of 839h or more (the best can reach 1000h), indicating that the modified PE film of the present invention also has good barrier and leakage resistance effects.

[0118] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. A person skilled in the art would be able to make other variations or modifications based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A modified PE film, characterized in that: The PE film comprises a seven-layer structure, which is, in order, a first polyethylene (PE) layer, a first metallocene polyethylene (PE) layer, a first TiC adhesive layer, an ethylene-vinyl alcohol copolymer barrier layer, a second TiC adhesive layer, a second metallocene polyethylene (PE) layer, and a second polyethylene (PE) layer; The mass content of the first polyethylene PE layer and the second polyethylene PE layer is 20% to 30% of the mass of the modified PE film; The mass content of the first metallocene polyethylene layer and the second metallocene polyethylene layer is 8% to 12% of the mass of the modified PE film; The mass content of the first TiC bonding layer and the second TiC bonding layer is 5% to 10% of the mass of the modified PE film; The mass content of the ethylene-vinyl alcohol copolymer barrier layer is 15% to 25% of the modified PE film.

2. The modified PE film according to claim 1, wherein The number average molecular weight of the polyethylene in the first polyethylene PE layer and the second polyethylene PE layer is 10,000 to 100,000, and the melt mass flow rate is 1.8 to 2.2 g / 10 min.

3. The modified PE film according to claim 1, wherein The melt mass flow rate of the metallocene polyethylene of the first metallocene polyethylene layer and the second metallocene polyethylene layer is ≧1.6 g / 10 min.

4. The modified PE film according to claim 1, wherein The melt mass flow rate of the ethylene-vinyl alcohol copolymer of the ethylene-vinyl alcohol copolymer barrier layer is 1.8 to 2.2 g / 10 min.

5. A method for preparing the modified PE film according to any one of claims 1 to 4, characterized in that: The steps include: Polyethylene, metallocene polyethylene, TiC and ethylene-vinyl alcohol copolymer are extruded through a co-extruder, extruded through a multi-channel composite die head, and cooled and shaped to obtain a modified PE film.

6. Use of the modified PE film according to any one of claims 1 to 4 in the preparation of pipes.

7. A PE water supply pipe, characterized in that: The PE water supply pipe comprises the modified PE film according to any one of claims 1 to 4.

8. The PE water supply pipe according to claim 7, characterized in that: The PE water supply pipe comprises a three-layer structure, the middle layer is the modified PE film according to any one of claims 1 to 4, and the inner and outer layers are both PE layers.

9. The PE water supply pipe according to claim 8, characterized in that: The PE of the inner layer and the outer layer is HDPE.

10. A method for preparing the PE water supply pipe according to any one of claims 7 to 9, characterized in that: The steps include: First, the inner layer of HDPE core tube is extruded through an extruder and cooled to shape; the core tube is heated to a certain temperature by a hot drying device, and a flowing film is extruded through a co-extruder to cover the outer wall of the core tube to form a protective film; Then, an extruder is used to attach a layer of HDPE material to the outer layer of the protective film; and the PE water supply pipe is produced by cooling and shaping through a cooling and shaping device.

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