Multilayer co-extruded super-hydrophobic polyethylene film and preparation method thereof

Abstract

The invention discloses a multi-layer co-extruded super-hydrophobic polyethylene film and a preparation method thereof. The film is composed of two surface layers sandwiching an intermediate layer. The contact angle between the film surface and water is between 153° and 158°, the rolling angle is less than 9°, and the liquid adhesion rate is less than 0.1%. After rubbing the film surface with a rubber loaded with a 10N force for 100 to 200 times, the surface contact angle still reaches 153° to 156°. The preparation method comprises (1) uniformly mixing low-density polyethylene particles and nano-material particles and granulating; (2) co-extruding low-density polyethylene masterbatch, high-density polyethylene particles, and low-density polyethylene masterbatch in three layers to obtain a three-layer co-extruded thick film; (3) stretching the three-layer co-extruded thick film into a film to obtain a product. The multi-layer co-extruded super-hydrophobic polyethylene film of the present invention has stronger resistance to liquid adhesion, better surface wear resistance, better super-hydrophobic stability, and the preparation method is suitable for large-area preparation, and has excellent industrialization prospects.

Description

Technical Field

[0001] The invention belongs to the field of super hydrophobic films, and in particular relates to a multi-layer co-extruded super hydrophobic polyethylene film and a preparation method thereof. Background Art

[0002] In recent years, inspired by the lotus effect, super-hydrophobic films with a contact angle of more than 150° with water have become a hot topic of research at home and abroad. The typical characteristics of super-hydrophobic films are: water droplets or aqueous liquids (spray, saliva, blood, sewage, etc.) are usually spherical on the surface of super-hydrophobic films, and it is difficult for liquids to stay stably on the surface of super-hydrophobic films. As long as they are tilted at a very small angle or under the action of a breeze or slight external force, the liquid will quickly roll off the surface of the super-hydrophobic film, and while rolling, dust and other pollutants on the surface of the film will be taken away, thereby playing a self-cleaning role. When the super-hydrophobic film is immersed in water or aqueous liquid for a long time, there will be no liquid penetration, and after taking it out, its surface will not stick to droplets, so it has extremely strong waterproof, water-blocking, antibacterial, mildew-proof and anti-liquid adhesion properties. These unique properties make super-hydrophobic films have very broad application prospects in industry, agriculture and daily life.

[0003] Polyethylene film has the advantages of being non-toxic, tasteless, and cheap, and is widely used in packaging and industry and agriculture, but the contact angle of ordinary polyethylene film on the market with water is usually less than 110 °, and there is no self-cleaning property, and it is easily adhered to by materials such as dust and thick liquids. If the surface of the polyethylene film is given super-hydrophobicity, the adhesion of thick liquids on the surface of the film will be greatly reduced, and the surface will also be easier to clean, and the market demand is huge. At present, the method for preparing super-hydrophobic polyethylene film mainly includes: template method, etching method, microphase separation method, etc. However, the method for preparing super-hydrophobic polyethylene film reported is currently limited to the laboratory, and the main reason is that 2 bottlenecks are encountered: ① the method reported is difficult to prepare super-hydrophobic polyethylene film on a large scale, resulting in difficulty in practical application; ② the super-hydrophobic polyethylene film prepared by the reported method has poor surface wear resistance and poor super-hydrophobic stability.

[0004] Therefore, it is extremely important to develop a method that can be used for large-scale preparation and maintain high wear resistance and superhydrophobic stability on the surface of superhydrophobic polyethylene films. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a multilayer co-extruded super-hydrophobic polyethylene film which can be prepared over a large area and can maintain high wear resistance and super-hydrophobic stability on the surface of the super-hydrophobic polyethylene film and a preparation method thereof.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions.

[0007] A multi-layer co-extruded super-hydrophobic polyethylene film is composed of two surface layers with an intermediate layer sandwiched therebetween, wherein the surface layer is a nanoporous composite film layer made of low-density polyethylene particles and nanomaterial particles as raw materials, and the intermediate layer is a high-density polyethylene film layer; the contact angle between the surface of the multi-layer co-extruded super-hydrophobic polyethylene film and water is between 153° and 158°, the rolling angle of water droplets on the film surface is less than 9°, the adhesion rate of the multi-layer co-extruded super-hydrophobic polyethylene film after contact with liquid is less than 0.1%, and after rubbing the film surface with a rubber with a load of 10N for 100 to 200 times, the contact angle of the film surface still reaches 153° to 156°.

[0008] In the above-mentioned multi-layer co-extruded super-hydrophobic polyethylene film, preferably, the nano material particles include one or more of nano silicon dioxide particles, nano calcium carbonate particles and nano zinc oxide particles.

[0009] In the above-mentioned multi-layer co-extruded super-hydrophobic polyethylene film, preferably, the average particle size of the nano material particles is between 1 nm and 100 nm.

[0010] As a general technical concept, the present invention also provides a method for preparing the above-mentioned multi-layer co-extruded super-hydrophobic polyethylene film, comprising the following steps:

[0011] (1) uniformly mixing low-density polyethylene particles and nanomaterial particles and granulating them to obtain low-density polyethylene masterbatch; wherein the mass ratio of the low-density polyethylene particles to the nanomaterial particles is 5-10:2-1;

[0012] (2) placing low-density polyethylene masterbatch, high-density polyethylene particles, and low-density polyethylene masterbatch into three hoppers respectively, and performing three-layer co-extrusion to obtain a three-layer co-extruded thick film; wherein the mass ratio of the low-density polyethylene masterbatch, the high-density polyethylene particles, and the low-density polyethylene masterbatch is 1:5-50:1, and the thickness of the three-layer co-extruded thick film is 0.2 mm-1 mm;

[0013] (3) The three-layer co-extruded thick film is stretched to a film with a thickness of 0.005 mm to 0.1 mm to obtain a multi-layer co-extruded super-hydrophobic polyethylene film.

[0014] In the above-mentioned method for preparing the multi-layer co-extruded super-hydrophobic polyethylene film, preferably, in step (3), the three-layer co-extruded thick film is placed on a longitudinal and transverse stretching frame for stretching.

[0015] In the present invention, low-density polyethylene particles refer to commercial low-density polyethylene particle raw materials that have not been specially treated, with a density of 0.91-0.93 g / cm 3 .

[0016] In the present invention, high-density polyethylene particles refer to commercial high-density polyethylene particle raw materials that have not been specially treated, and have a density of 0.941-0.960 g / cm 3 .

[0017] In the present invention, the low-density polyethylene masterbatch refers to low-density polyethylene particles formed by mixing low-density polyethylene and nanoparticles.

[0018] Compared with the prior art, the advantages of the present invention are:

[0019] 1. Compared with the existing super-hydrophobic film, the multi-layer co-extruded super-hydrophobic polyethylene film of the present invention has stronger anti-liquid adhesion, better surface wear resistance, and better super-hydrophobic stability. The contact angle between the surface of the multi-layer co-extruded super-hydrophobic polyethylene film and water is between 153 ° and 158 °, and the rolling angle of water droplets on the film surface is less than 9 °. The multi-layer co-extruded super-hydrophobic polyethylene film has excellent anti-liquid adhesion performance, and the adhesion rate of liquids such as milk and ketchup after contacting them is less than 0.1%. After rubbing the film surface with a rubber with a load of 10N power for 100 to 200 times, the film surface contact angle still exceeds 153 °. The multi-layer co-extruded super-hydrophobic polyethylene film of the present invention can significantly reduce the adhesion of thick liquid on the film surface, and the surface is also easier to clean, and the film surface can also be kept dry for a long time, and there is a broader application prospect in the fields of packaging, glass and film, paper-plastic composite film of thick products (liquid milk, ketchup, etc.), and the market demand is huge.

[0020] 2. The preparation method of the present invention is low-cost, suitable for large-scale preparation, and has excellent industrialization prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a surface scanning electron microscope image of the multi-layer co-extruded super-hydrophobic polyethylene film obtained in Example 1 of the present invention.

[0022] Figure 2 This is a contact angle test diagram of the surface of the multi-layer co-extruded super-hydrophobic polyethylene film obtained in Example 1 of the present invention.

[0023] Figure 3 This is a contact angle test diagram of the surface of the multi-layer co-extruded super-hydrophobic polyethylene film obtained in Example 2 of the present invention.

[0024] Figure 4 This is a contact angle test diagram of the surface of the multi-layer co-extruded super-hydrophobic polyethylene film obtained in Example 3 of the present invention.

[0025] Figure 5 This is a contact angle test diagram of the surface of the multi-layer co-extruded super-hydrophobic polyethylene film obtained in Example 4 of the present invention.

[0026] Figure 6This is a contact angle test diagram of the surface of the multi-layer co-extruded super-hydrophobic polyethylene film obtained in Example 5 of the present invention. DETAILED DESCRIPTION

[0027] The present invention is further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the protection scope of the present invention is not limited thereby. The materials and instruments used in the following embodiments are all commercially available.

[0028] Example 1

[0029] A method for preparing a multi-layer co-extruded super-hydrophobic polyethylene film of the present invention comprises the following steps:

[0030] (1) low-density polyethylene particles and nano-silicon dioxide particles with an average particle size of 30 nm are uniformly mixed in a mass ratio of 5:2 and granulated to form a low-density polyethylene masterbatch;

[0031] (2) Weighing low-density polyethylene masterbatch, high-density polyethylene particles, and low-density polyethylene masterbatch in a mass ratio of 1:5:1, and placing them in corresponding hoppers, respectively, and extruding a three-layer co-extruded thick film with a thickness of 0.2 mm through a three-layer co-extruder;

[0032] (3) The three-layer co-extruded thick film was placed on a longitudinal and transverse stretching frame and stretched at a uniform speed to a film thickness of 0.005 mm to obtain a multi-layer co-extruded super-hydrophobic polyethylene film. The scanning electron microscope image of the film surface morphology is shown in FIG. Figure 1 shown.

[0033] The multi-layer co-extruded super-hydrophobic polyethylene film of this embodiment is composed of two surface layers (exterior layers) sandwiched by an intermediate layer, namely, surface layer-intermediate layer-surface layer. The two surface layers are nanoporous composite film layers, and the nanoporous composite film layers are made of low-density polyethylene particles and nanomaterial particles as raw materials. The intermediate layer is a high-density polyethylene film layer. Figure 2 As shown in the figure, the contact angle test results show that the contact angle of water droplets on the surface of the multi-layer co-extruded super-hydrophobic polyethylene film of this embodiment is 153°, and the rolling angle of water droplets on the film surface is 8°. The adhesion rate of milk after contacting the surface of the multi-layer co-extruded super-hydrophobic polyethylene film is less than 0.1%. After rubbing the film surface with a rubber with a load of 10N force for 100 times, the contact angle of the film surface is still maintained at 153°, which reflects excellent anti-liquid adhesion and wear resistance.

[0034] Example 2

[0035] A method for preparing a multi-layer co-extruded super-hydrophobic polyethylene film of the present invention comprises the following steps:

[0036] (1) mixing low-density polyethylene particles and nano-calcium carbonate particles with an average particle size of 60 nm in a mass ratio of 10:1 and granulating to form a low-density polyethylene masterbatch;

[0037] (2) Weighing low-density polyethylene masterbatch, high-density polyethylene particles, and low-density polyethylene masterbatch in a mass ratio of 1:50:1, and placing them in corresponding hoppers, respectively, and extruding a three-layer co-extruded thick film with a thickness of 1 mm through a three-layer co-extruder;

[0038] (3) The three-layer co-extruded thick film is placed on a longitudinal and transverse stretching frame and stretched at a uniform speed to a film thickness of 0.1 mm to obtain a multi-layer co-extruded super-hydrophobic polyethylene film.

[0039] The multi-layer co-extruded super-hydrophobic polyethylene film of this embodiment is composed of two surface layers sandwiched by an intermediate layer, the two surface layers are nanoporous composite film layers, the nanoporous composite film layers are made of low-density polyethylene particles and nanomaterial particles as raw materials, and the intermediate layer is a high-density polyethylene film layer. Figure 3 As shown, the contact angle test results show that the contact angle of water droplets on the surface of the multi-layer co-extruded super hydrophobic polyethylene film of this embodiment is 158°, the rolling angle of water droplets on the film surface is 2°, the adhesion rate of the film surface after contact with ketchup is less than 0.08%, and after rubbing the film surface with a rubber with a load of 10N force for 200 times, the contact angle of the film surface is still maintained at 155°, which reflects excellent resistance to liquid adhesion and wear resistance.

[0040] Example 3

[0041] A method for preparing a multi-layer co-extruded super-hydrophobic polyethylene film of the present invention comprises the following steps:

[0042] (1) low-density polyethylene particles and nano zinc oxide particles with an average particle size of 80 nm are uniformly mixed in a mass ratio of 8:2 and granulated to form a low-density polyethylene masterbatch;

[0043] (2) Weighing low-density polyethylene masterbatch, high-density polyethylene particles, and low-density polyethylene masterbatch in a mass ratio of 1:10:1, and placing them in corresponding hoppers, respectively, and extruding a three-layer co-extruded thick film with a thickness of 0.5 mm through a three-layer co-extruder;

[0044] (3) The three-layer co-extruded thick film is placed on a longitudinal and transverse stretching frame and stretched at a uniform speed to a film thickness of 0.05 mm to obtain a multi-layer co-extruded super-hydrophobic polyethylene film.

[0045] The multi-layer co-extruded super-hydrophobic polyethylene film of this embodiment is composed of two surface layers sandwiched by an intermediate layer, the two surface layers are nanoporous composite film layers, the nanoporous composite film layers are made of low-density polyethylene particles and nanomaterial particles as raw materials, and the intermediate layer is a high-density polyethylene film layer. Figure 4As shown in the figure, the contact angle test results show that the contact angle of water droplets on the film surface is 157°, and the rolling angle of water droplets on the film surface is 3°. The adhesion rate of milk after contacting the surface of the multi-layer co-extruded super-hydrophobic polyethylene film is less than 0.05%. After rubbing the film surface with a rubber with a load of 10N for 100 times, the contact angle of the film surface still remains at 156°, reflecting excellent anti-liquid adhesion and wear resistance.

[0046] Example 4

[0047] A method for preparing a multi-layer co-extruded super-hydrophobic polyethylene film of the present invention comprises the following steps:

[0048] (1) low-density polyethylene particles and nano zinc oxide particles with an average particle size of 50 nm are uniformly mixed in a mass ratio of 9:2 and granulated to form a low-density polyethylene masterbatch;

[0049] (2) Weighing low-density polyethylene masterbatch, high-density polyethylene particles, and low-density polyethylene masterbatch in a mass ratio of 1:20:1, and placing them in corresponding hoppers, respectively, and extruding a three-layer co-extruded thick film with a thickness of 0.6 mm through a three-layer co-extruder;

[0050] (3) The three-layer co-extruded thick film is placed on a longitudinal and transverse stretching frame and stretched at a uniform speed to a film thickness of 0.08 mm to obtain a multi-layer co-extruded super-hydrophobic polyethylene film.

[0051] The multi-layer co-extruded super-hydrophobic polyethylene film of this embodiment is composed of two surface layers sandwiched by an intermediate layer, the two surface layers are nanoporous composite film layers, the nanoporous composite film layers are made of low-density polyethylene particles and nanomaterial particles as raw materials, and the intermediate layer is a high-density polyethylene film layer. Figure 5 As shown in the figure, the contact angle test results show that the contact angle of water droplets on the surface of the multi-layer co-extruded super-hydrophobic polyethylene film of this embodiment is 155°, and the rolling angle of water droplets on the film surface is 5°. The adhesion rate of milk after contacting the surface of the multi-layer co-extruded super-hydrophobic polyethylene film is less than 0.03%. After rubbing the film surface with a rubber with a load of 10N for 150 times, the contact angle of the film surface is still maintained at 153°, which reflects excellent anti-liquid adhesion and wear resistance.

[0052] Example 5

[0053] A method for preparing a multi-layer co-extruded super-hydrophobic polyethylene film of the present invention comprises the following steps:

[0054] (1) low-density polyethylene particles and nano-calcium carbonate particles with an average particle size of 50 nm are uniformly mixed in a mass ratio of 9:1 and granulated to form a low-density polyethylene masterbatch;

[0055] (2) Weighing low-density polyethylene masterbatch, high-density polyethylene particles, and low-density polyethylene masterbatch in a mass ratio of 1:30:1, and placing them in corresponding hoppers, respectively, and extruding a three-layer co-extruded thick film with a thickness of 0.8 mm through a three-layer co-extruder;

[0056] (3) The three-layer co-extruded thick film is placed on a longitudinal and transverse stretching frame and stretched at a uniform speed to a film thickness of 0.01 mm to obtain a multi-layer co-extruded super-hydrophobic polyethylene film.

[0057] The multi-layer co-extruded super-hydrophobic polyethylene film of this embodiment is composed of two surface layers sandwiched by an intermediate layer, the two surface layers are nanoporous composite film layers, the nanoporous composite film layers are made of low-density polyethylene particles and nanomaterial particles as raw materials, and the intermediate layer is a high-density polyethylene film layer. Figure 6 As shown in the figure, the contact angle test results show that the contact angle of water droplets on the surface of the multi-layer co-extruded super-hydrophobic polyethylene film of this embodiment is 154°, and the rolling angle of water droplets on the film surface is 7°. The adhesion rate of ketchup after contact with the surface of the multi-layer co-extruded super-hydrophobic polyethylene film is less than 0.08%. After rubbing the film surface with a rubber with a load of 10N for 160 times, the contact angle of the film surface is still maintained at 153°, which reflects excellent anti-liquid adhesion and wear resistance.

[0058] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as above in the preferred embodiment, it is not used to limit the present invention. Any technician familiar with the art can make many possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention, still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A multi-layer co-extruded super-hydrophobic polyethylene film, characterized in that: The invention is composed of two surface layers sandwiching an intermediate layer, wherein the surface layer is a nanoporous composite film layer, the nanoporous composite film layer is made of low-density polyethylene particles and nanomaterial particles as raw materials, and the intermediate layer is a high-density polyethylene film layer; the contact angle between the surface of the multi-layer co-extruded super-hydrophobic polyethylene film and water is between 153° and 158°, the rolling angle of water droplets on the film surface is less than 9°, the adhesion rate of the multi-layer co-extruded super-hydrophobic polyethylene film after contact with liquid is less than 0.1%, and after rubbing the film surface with a rubber with a load of 10N for 100 to 200 times, the contact angle of the film surface still reaches 153° to 156°; The nano material particles include one or more of nano silicon dioxide particles, nano calcium carbonate particles and nano zinc oxide particles; The average particle size of the nanomaterial particles is between 1nm and 100nm; The multi-layer co-extruded super-hydrophobic polyethylene film is obtained by stretching a three-layer co-extruded thick film, and the thickness of the multi-layer co-extruded super-hydrophobic polyethylene film is 0.005 mm to 0.1 mm.

2. A method for preparing a multi-layer co-extruded super-hydrophobic polyethylene film as claimed in claim 1, characterized in that: The following steps are involved: (1) uniformly mixing low-density polyethylene particles and nanomaterial particles and granulating them to obtain low-density polyethylene masterbatch; wherein the mass ratio of the low-density polyethylene particles to the nanomaterial particles is 5-10:2-1; (2) placing low-density polyethylene masterbatch, high-density polyethylene granules, and low-density polyethylene masterbatch into three hoppers respectively, and performing three-layer co-extrusion to obtain a three-layer co-extruded thick film; wherein the mass ratio of the low-density polyethylene masterbatch, the high-density polyethylene granules, and the low-density polyethylene masterbatch is 1:5-50:1, and the thickness of the three-layer co-extruded thick film is 0.2 mm-1 mm; (3) The three-layer co-extruded thick film is stretched to a film with a thickness of 0.005 mm to 0.1 mm to obtain a multi-layer co-extruded super-hydrophobic polyethylene film.

3. The method for preparing a multi-layer co-extruded super hydrophobic polyethylene film according to claim 2, wherein: In step (3), the three-layer co-extruded thick film is placed on longitudinal and transverse stretching frames for stretching.

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