High-covering PE film and preparation method thereof

Abstract

The invention relates to the technical field of high polymer materials, in particular to a high-covering PE film and a preparation method thereof.The high-covering PE film comprises PE matrix resin and high-covering master batch added into the PE matrix resin, the PE matrix resin is a blend of linear low-density polyethylene and low-density polyethylene, and the high-covering master batch is composed of nanoscale carbon black, titanium dioxide and a dispersing agent; the preparation method of the high-covering master batch comprises the following steps: S1, preparing PE matrix resin; S2, preparing an intermediate A; S3, preparing the high-covering master batch; S4, preparing an intermediate B; according to the high-covering PE film and the preparation method thereof, the covering performance of the PE film is effectively improved by adding the nanoscale carbon black and the titanium dioxide, the packaging requirement for light-sensitive products can be met, the specific PE matrix resin formula and the specific preparation process are adopted, the covering performance is improved, and meanwhile, the high-covering PE film is prepared. Good comprehensive performances such as flexibility, good heat sealing performance and mechanical strength of the PE film are maintained.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, in particular to a high-hiding PE film and a preparation method thereof. Background Art

[0002] PE film refers to a film produced from polyethylene particles. It is moisture-proof and has low moisture permeability. Polyethylene is non-toxic and odorless, has excellent low-temperature resistance, good chemical stability, can withstand the erosion of most acids and alkalis, and has good insulation properties. It is widely used in various industries such as medicine, chemical industry, food, and printing.

[0003] At present, ordinary milky white PE film has shortcomings in some application scenarios that require high hiding properties, such as packaging light-sensitive products and items that require privacy protection. The traditional method of improving hiding properties requires adding aluminized film or aluminum foil in the middle of the composite film to improve hiding properties. This structure increases the material cost and production cost very high, and at the same time affects other properties of the PE film, such as flexibility and mechanical strength. It is necessary to develop a new material that has high hiding properties and maintains the good comprehensive performance of the PE film. Therefore, a high-hiding PE film and its preparation method are urgently needed to improve the above problems. Summary of the Invention

[0004] The object of the present invention is to solve at least one of the technical drawbacks.

[0005] To this end, one object of the present invention is to provide a high-hiding PE film and a preparation method thereof, so as to solve the problems mentioned in the background art and overcome the deficiencies in the prior art.

[0006] To achieve the above objectives, an embodiment of one aspect of the present invention provides a high-hiding PE film and a preparation method thereof, comprising a PE base resin and a high-hiding masterbatch added thereto, wherein the PE base resin is a blend of linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE), and the high-hiding masterbatch is composed of nano-scale carbon black, titanium dioxide, and a dispersant;

[0007] The preparation method of the high hiding masterbatch comprises the following steps:

[0008] S1: preparing a PE matrix resin by adding linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE) into a mixer and mixing them to obtain a PE matrix resin;

[0009] S2: preparing intermediate A by mixing nano-scale carbon black, titanium dioxide and a dispersant in a certain proportion so that the carbon black and titanium dioxide are uniformly dispersed in the dispersant to obtain intermediate A;

[0010] S3: preparing a high-cover masterbatch, adding intermediate A into a twin-screw extruder, and extruding and granulating by a twin-screw extruder to obtain a high-cover masterbatch;

[0011] S4: Prepare intermediate B, add high hiding masterbatch and PE matrix resin into the extruder according to the proportion, melt-blend the high hiding masterbatch and PE matrix resin to obtain intermediate B,

[0012] S5: preparing a high-hiding PE film, adding the intermediate B into a film blowing machine, and producing a high-hiding PE film through a film blowing process of the film blowing machine.

[0013] The present invention is further configured as follows: the mass fraction of LLDPE in the PE matrix resin is 60%-80%, and the mass fraction of LDPE is 10%-20%.

[0014] By adopting the above technical solution and using a specific PE matrix resin formula and preparation process, while improving the covering property, the good comprehensive properties of the PE film, such as flexibility, good heat sealing performance, and mechanical strength, are maintained.

[0015] The present invention is further configured such that the mass of the high hiding masterbatch is 10%-20% of the mass of the PE matrix resin.

[0016] The present invention is further configured as follows: in S2, nano-scale carbon black, titanium dioxide and dispersant are added into a high-speed stirrer according to proportion, and stirred and mixed at 100-150° C. for 30-60 minutes.

[0017] By adopting the above technical solution, the covering performance of the PE film is effectively improved.

[0018] The present invention is further configured as follows: in S4, the high hiding masterbatch and the PE matrix resin are added to the extruder in proportion, and melt-blended at 160-200°C.

[0019] By adopting the above technical solution, a high-hiding PE film can be produced.

[0020] In summary, the beneficial technical effects of the present invention are:

[0021] 1. This high-hiding PE film and its preparation method effectively improve the hiding properties of the PE film by adding nano-scale carbon black and titanium dioxide. Its visible light transmittance (T) is less than 5% and its haze (H) is 100%, meeting the packaging needs of light-sensitive products.

[0022] 2. The high-hiding PE film and its preparation method adopt a specific PE matrix resin formula and preparation process, which improves the hiding power while maintaining the good comprehensive properties of the PE film, such as flexibility, good heat sealing performance, and mechanical strength.

[0023] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned through practice of the present invention. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0025] Example 1

[0026] The present invention discloses a high-hiding PE film and a preparation method thereof, comprising a PE base resin and a high-hiding masterbatch added thereto, wherein the PE base resin is a blend of linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE), and the high-hiding masterbatch is composed of nano-scale carbon black, titanium dioxide, and a dispersant;

[0027] The preparation method of the high hiding masterbatch comprises the following steps:

[0028] S1: preparing a PE matrix resin by adding linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE) into a mixer and mixing them to obtain a PE matrix resin;

[0029] S2: preparing intermediate A by mixing nano-scale carbon black, titanium dioxide and a dispersant in a certain proportion so that the carbon black and titanium dioxide are uniformly dispersed in the dispersant to obtain intermediate A;

[0030] S3: preparing a high-cover masterbatch, adding intermediate A into a twin-screw extruder, and extruding and granulating by a twin-screw extruder to obtain a high-cover masterbatch;

[0031] S4: Prepare intermediate B, add high hiding masterbatch and PE matrix resin into the extruder according to the proportion, melt-blend the high hiding masterbatch and PE matrix resin to obtain intermediate B,

[0032] S5: preparing a high-hiding PE film, adding the intermediate B into a film blowing machine, and producing a high-hiding PE film through a film blowing process of the film blowing machine.

[0033] The mass fraction of LLDPE in the PE matrix resin is 60%-80%, and the mass fraction of LDPE is 10%-20%. A specific PE matrix resin formula and preparation process are adopted to improve the hiding property while maintaining the good comprehensive properties of the PE film, such as flexibility, good heat sealing performance, and mechanical strength. The mass of the high-hiding masterbatch is 10%-20% of the mass of the PE matrix resin. In S2, nano-scale carbon black, titanium dioxide and dispersant are added to a high-speed mixer in proportion, and stirred and mixed at 100-150°C for 30-60 minutes, thereby effectively improving the hiding property of the PE film. In S4, the high-hiding masterbatch and the PE matrix resin are added to an extruder in proportion, and melt-blended at 160-200°C to produce a high-hiding PE film.

[0034] A PE matrix resin was prepared by blending 75% LLDPE and 25% LDPE by weight. A high-hiding masterbatch (5% by weight of the PE matrix resin) was added to the PE matrix resin. The masterbatch was prepared by mixing nano-carbon black, titanium dioxide, and a dispersant in a high-speed blender at 120°C for 40 minutes, followed by extrusion and pelletization through a twin-screw extruder. The two mixtures were melt-blended in an extruder at 180°C, and then formed into a high-hiding PE film using a blown film process. Testing revealed that the film had a visible light transmittance of 3%, an elongation at break of 350%, and a tensile strength of 18 MPa.

[0035] Example 2

[0036] Based on the above embodiment, the preparation of the composite nano-modifier includes the following steps: blending 80% LLDPE and 20% LDPE with a mass fraction as a PE matrix resin, adding a high-hiding masterbatch with a mass of 3% of the mass of the PE matrix resin to the PE matrix resin, and preparing a high-hiding PE film according to the same method as Example 1. After testing, the film has a visible light transmittance of 4%, an elongation at break of 320%, and a tensile strength of 16 MPa.

[0037] The implementation principle of this embodiment is:

[0038] The high-hiding PE film and its preparation method are as follows: during preparation, the staff adds linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE) into a mixer and mixes them. During this process, the mass fraction of LLDPE is 60%-80%, and the mass fraction of LDPE is 10%-20%, so as to obtain a PE matrix resin. Subsequently, the staff adds nano-scale carbon black, titanium dioxide and a dispersant in a high-speed mixer according to a certain proportion and mixes them. This process lasts for 30-60 minutes, so that the carbon black and titanium dioxide are evenly dispersed in the dispersant to obtain an intermediate A. Subsequently, the staff adds the intermediate A into a twin-screw extruder and extrudes and granulates it through the twin-screw extruder to obtain a high-hiding masterbatch. Finally, the staff added the high-hiding masterbatch and PE matrix resin into the extruder in proportion, and melt-blended the high-hiding masterbatch and PE matrix resin at 160-200°C to obtain intermediate B. In this process, the mass of the high-hiding masterbatch is 10%-20% of the mass of the PE matrix resin. Subsequently, intermediate B will enter the interior of the film blowing machine, and the high-hiding PE film will be produced through the film blowing process of the film blowing machine. By adding nano-scale carbon black and titanium dioxide, the hiding performance of the PE film is effectively improved, which can meet the packaging requirements of light-sensitive products. The specific PE matrix resin formula and preparation process are used to improve the hiding property while maintaining the good comprehensive properties of the PE film such as flexibility, good heat sealing performance, and mechanical strength.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] 1. This high-hiding PE film and its preparation method effectively improve the hiding properties of the PE film by adding nano-scale carbon black and titanium dioxide. Its visible light transmittance (T) is less than 5% and its haze (H) is 100%, meeting the packaging needs of light-sensitive products.

[0041] 2. The high-hiding PE film and its preparation method adopt a specific PE matrix resin formula and preparation process, which improves the hiding power while maintaining the good comprehensive properties of the PE film, such as flexibility, good heat sealing performance, and mechanical strength.

[0042] The embodiments of this specific implementation method are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high hiding PE film, characterized by: It includes a PE matrix resin and a high-hiding masterbatch added thereto, wherein the PE matrix resin is a blend of linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE), and the high-hiding masterbatch is composed of nano-scale carbon black, titanium dioxide, and a dispersant; The preparation method of the high hiding masterbatch comprises the following steps: S1: preparing a PE matrix resin by adding linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE) into a mixer and mixing them to obtain a PE matrix resin; S2: preparing intermediate A by mixing nano-scale carbon black, titanium dioxide and a dispersant in a certain proportion so that the carbon black and titanium dioxide are uniformly dispersed in the dispersant to obtain intermediate A; S3: preparing a high-cover masterbatch, adding intermediate A into a twin-screw extruder, and extruding and granulating by a twin-screw extruder to obtain a high-cover masterbatch; S4: Prepare intermediate B, add high hiding masterbatch and PE matrix resin into the extruder according to the proportion, melt-blend the high hiding masterbatch and PE matrix resin to obtain intermediate B, S5: preparing a high-hiding PE film, adding the intermediate B into a film blowing machine, and producing a high-hiding PE film through a film blowing process of the film blowing machine.

2. The method for preparing a high-hiding PE film according to claim 1, wherein: The mass fraction of LLDPE in the PE matrix resin is 60%-80%, and the mass fraction of LDPE is 10%-20%.

3. The method for preparing a high-hiding PE film according to claim 1, wherein: The mass of the high hiding masterbatch is 10%-20% of the mass of the PE matrix resin.

4. The method for preparing a high-hiding PE film according to claim 1, wherein: In the S2, nano-scale carbon black, titanium dioxide and dispersant are added into a high-speed mixer according to a certain proportion, and stirred and mixed at 100-150° C. for 30-60 minutes.

5. The method for preparing a high hiding PE film according to claim 1, wherein: In the S4, the high hiding masterbatch and the PE matrix resin are added to the extruder in proportion and melt-blended at 160-200°C.