Multi-layer co-extrusion production process of high-density polyethylene film

Abstract

The invention provides a multi-layer co-extrusion production process of a high-density polyethylene film, and relates to the technical field of plastic film production. The multi-layer co-extrusion production process of the high-density polyethylene film comprises the following steps: selecting main raw materials and auxiliary materials; selecting a multi-layer co-extrusion extruder; respectively adding the prepared main raw materials and auxiliary materials into a multi-layer co-extrusion extruder to form a melt with a multi-layer structure; carrying out longitudinal stretching and transverse stretching on the melt; carrying out corona treatment on the stretched film; the treated film is wound through a winding device, and the finished high-density polyethylene film is formed. Through a multi-layer co-extrusion technology, high-density polyethylene resins with different properties are combined together, so that the film has better barrier property, mechanical property and heat sealing property on the basis of keeping the original advantages of high-density polyethylene, and the application range of the film is widened. Meanwhile, the production process has the advantages of high production efficiency, stable product quality and the like.

Description

Technical Field

[0001] The invention relates to the technical field of plastic film production, in particular to a multi-layer co-extrusion production process of a high-density polyethylene film. Background Art

[0002] High-density polyethylene (HDPE), also known as low-pressure polyethylene, is a highly crystalline, non-polar surface that is somewhat translucent. PE has excellent resistance to most household and industrial chemicals.

[0003] High-density polyethylene film has good mechanical strength, chemical stability and weather resistance, and is widely used in packaging, agriculture, construction and other fields. However, traditional single-layer HDPE film has limitations in certain properties, such as barrier properties and mechanical properties. The emergence of multi-layer co-extrusion technology provides an effective way to improve the performance of HDPE film, but the existing co-extrusion technology still has some problems, such as poor interlayer adhesion and low processing efficiency. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the deficiencies of the prior art, the present invention provides a multi-layer co-extrusion production process for high-density polyethylene film, which solves the problems raised by the background technology.

[0006] (II) Technical solution

[0007] To achieve the above object, the present invention is implemented by the following technical scheme: A multi-layer co-extrusion production process of high-density polyethylene film, comprising the following steps:

[0008] Step 1: Raw material preparation:

[0009] Select nylon, polyethylene, acid-modified polyolefin composites, ethylene tetrafluoroethylene polymers, and polytetrafluoroethylene as the main raw materials, and prepare auxiliary materials to improve the processing and use properties of the film;

[0010] Step 2: Extruder preparation:

[0011] Select a multi-layer co-extrusion extruder, and preheat and debug the multi-layer co-extrusion extruder;

[0012] Step 3: Extrusion molding:

[0013] The prepared main raw materials and auxiliary materials are added into the multi-layer co-extruder respectively, and melted and plasticized by heating and the shearing action of the screw, so that the molten materials converge at the die head to form a melt with a multi-layer structure;

[0014] Step 4: Stretch and shape:

[0015] The melt is longitudinally stretched by the mechanical force of extrusion blow molding in the extruder, and simultaneously or laterally stretched by compressed air blowing, and cooled, so that the multilayer composite film is blown into a thin film;

[0016] Step 5: Corona treatment:

[0017] Corona treatment is performed on the stretched film;

[0018] Step 6: Rolling up:

[0019] The treated film is rolled up by a rolling device to form a finished high-density polyethylene film.

[0020] Preferably, in step one, the auxiliary materials include a lubricant, an antistatic agent, an antioxidant and an antibacterial agent.

[0021] Preferably, the lubricant is polyethylene wax, the antistatic agent is ethylene bisstearamide, the antioxidant is 2,6-di-tert-butyl-p-cresol, and the antibacterial agent is nano-silver particles.

[0022] Preferably, in step 2, the multi-layer co-extrusion extruder comprises a plurality of extrusion units, each of which is responsible for extruding one type of material.

[0023] Preferably, in step three, the die head is a co-extrusion die head having a plurality of feed ports, each of which corresponds to an extrusion unit, to ensure that the raw materials of each layer converge evenly at the die head.

[0024] Preferably, in step four, the multi-layer co-extrusion extruder is co-extruded with multiple extrusion units, extruded at one die head, and the multi-layer co-extrusion extruder is equipped with a fan and a cooling ring located at the die head to cool the multi-layer film in the cooling line, and finally a high-density polyethylene film is obtained.

[0025] Preferably, in step 4, the cooling method is air cooling or water cooling.

[0026] Preferably, in step five, the corona treatment is operated by applying a high voltage to the film surface to generate a corona discharge phenomenon, thereby forming a fine concave-convex structure on the film surface, improving the surface tension and adhesion of the film, and making it easier to print and composite.

[0027] Preferably, in step six, the winding device includes a tension control device to ensure that the film maintains appropriate tension during the winding process to avoid the film from becoming loose or breaking.

[0028] Preferably, the multi-layer co-extrusion production process of the high-density polyethylene film further comprises the following steps:

[0029] Slitting: Place the shaped high-density polyethylene film on the slitting machine, and then start the slitting machine. After a period of time, the slitting machine will divide the high-density polyethylene film into several groups of equal amounts;

[0030] Inspection: The slit high-density polyethylene film is inspected by the existing inspection device. By observing the values ​​of the inspection device, it is determined whether the production of the fluororesin film meets the standards, and then the fluororesin film that does not meet the standards is processed again;

[0031] Step 8: Packaging: Label the multi-layer composite films that meet the relevant requirements and those that do not meet the relevant requirements after inspection. The films that meet the relevant requirements are packaged and put into the finished product raw material area.

[0032] (III) Beneficial effects

[0033] The present invention provides a multi-layer co-extrusion production process of a high-density polyethylene film, which has the following beneficial effects:

[0034] 1. Through multi-layer co-extrusion technology, high-density polyethylene resins with different properties are combined together, so that the film has better barrier properties, mechanical properties and heat sealing properties while maintaining the original advantages of high-density polyethylene, thus broadening its application range. At the same time, this production process has the advantages of high production efficiency and stable product quality.

[0035] 2. Improved the comprehensive performance of the film: Through the multi-layer co-extrusion technology, material layers with different characteristics can be superimposed together, thereby giving the film better barrier properties, mechanical strength and weather resistance, meeting the needs of different application fields, and improving the interlayer adhesion: The present invention optimizes the extrusion unit and die head design of the extruder to ensure that the raw materials of each layer are evenly converged during the extrusion process, thereby improving the interlayer adhesion and avoiding stratification.

[0036] 3. Enhanced the surface properties of the film: The corona treatment step forms a fine concave-convex structure on the surface of the film, increases the surface tension and adhesion, and makes the film easier to carry out subsequent printing and lamination operations.

[0037] In summary, the present invention provides a multi-layer co-extrusion production process for high-density polyethylene film, which not only improves the comprehensive performance and processing efficiency of the film, but also ensures product quality, and has significant economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of the production process of the present invention. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] Embodiment 1:

[0041] like Figure 1 As shown, an embodiment of the present invention provides a multi-layer co-extrusion production process of a high-density polyethylene film, comprising the following steps:

[0042] Step 1: Raw material preparation:

[0043] Nylon, polyethylene, acid-modified polyolefin composites, ethylene tetrafluoroethylene polymers, and polytetrafluoroethylene are selected as main raw materials, and auxiliary materials for improving the processing performance and use performance of the film are prepared, the auxiliary materials including a lubricant, an antistatic agent, an antioxidant, and an antibacterial agent. Specifically, the lubricant is polyethylene wax, the antistatic agent is ethylene bisstearamide, the antioxidant is 2,6-di-tert-butyl-p-cresol, and the antibacterial agent is nano silver particles;

[0044] Step 2: Extruder preparation:

[0045] Select a multi-layer co-extrusion extruder, which includes three extrusion units, each of which is responsible for extruding one material, and preheat and debug the multi-layer co-extrusion extruder;

[0046] Step 3: Extrusion molding:

[0047] The prepared main raw materials and auxiliary materials are added to the multi-layer co-extruder respectively, and melted and plasticized by heating and the shearing action of the screw, so that the molten materials converge at the die head. Specifically, the die head is a co-extrusion die head with three feed ports, each of which corresponds to an extrusion unit to ensure that the raw materials of each layer converge evenly at the die head to form a melt of a multi-layer structure;

[0048] Step 4: Stretch and shape:

[0049] The melt is longitudinally stretched by the mechanical force of extrusion blow molding in the extruder, and at the same time or later, is transversely stretched by compressed air blowing, and is cooled by air cooling, so that the multi-layer composite film is blown into a film, and then, it is co-extruded by multiple extrusion units of the multi-layer co-extrusion extruder, extruded in one die, and the multi-layer film in the cooling line is cooled by the fan of the multi-layer co-extrusion extruder and the cooling ring located in the die, and finally a high-density polyethylene film is obtained;

[0050] Step 5: Corona treatment:

[0051] The stretched film is subjected to corona treatment. Specifically, the operation method of the corona treatment is: applying a high voltage to the surface of the film to generate a corona discharge phenomenon, thereby forming a fine concave-convex structure on the surface of the film, improving the surface tension and adhesion of the film, making it easier to print and laminate;

[0052] Step 6: Rolling up:

[0053] The treated film is wound up by a winding device, which includes a tension control device to ensure that the film maintains appropriate tension during the winding process to avoid film relaxation or breakage, thereby forming a finished high-density polyethylene film.

[0054] Embodiment 2:

[0055] like Figure 1 As shown, an embodiment of the present invention provides a multi-layer co-extrusion production process of a high-density polyethylene film, comprising the following steps:

[0056] Step 1: Raw material preparation:

[0057] Nylon, polyethylene, acid-modified polyolefin composites, ethylene tetrafluoroethylene polymers, and polytetrafluoroethylene are selected as main raw materials, and auxiliary materials for improving the processing performance and use performance of the film are prepared, the auxiliary materials including a lubricant, an antistatic agent, an antioxidant, and an antibacterial agent. Specifically, the lubricant is polyethylene wax, the antistatic agent is ethylene bisstearamide, the antioxidant is 2,6-di-tert-butyl-p-cresol, and the antibacterial agent is nano silver particles;

[0058] Step 2: Extruder preparation:

[0059] Select a multi-layer co-extrusion extruder, which includes four extrusion units, each of which is responsible for extruding one material, and preheat and debug the multi-layer co-extrusion extruder;

[0060] Step 3: Extrusion molding:

[0061] The prepared main raw materials and auxiliary materials are added to the multi-layer co-extruder respectively, and melted and plasticized by heating and the shearing action of the screw, so that the molten materials converge at the die head. Specifically, the die head is a co-extrusion die head with four feed ports, each of which corresponds to an extrusion unit to ensure that the raw materials of each layer converge evenly at the die head to form a melt of a multi-layer structure;

[0062] Step 4: Stretch and shape:

[0063] The melt is longitudinally stretched by the mechanical force of extrusion blow molding in the extruder, and at the same time or later, is transversely stretched by compressed air blowing, and is cooled by water cooling, so that the multi-layer composite film is blown into a film, and then, it is co-extruded by multiple extrusion units of the multi-layer co-extrusion extruder, extruded in one die, and the multi-layer film in the cooling line is cooled by the fan of the multi-layer co-extrusion extruder and the cooling ring located in the die, and finally a high-density polyethylene film is obtained;

[0064] Step 5: Corona treatment:

[0065] The stretched film is subjected to corona treatment. Specifically, the operation method of the corona treatment is: applying a high voltage to the surface of the film to generate a corona discharge phenomenon, thereby forming a fine concave-convex structure on the surface of the film, improving the surface tension and adhesion of the film, making it easier to print and laminate;

[0066] Step 6: Rolling up:

[0067] The treated film is wound up by a winding device, which includes a tension control device to ensure that the film maintains appropriate tension during the winding process to avoid film relaxation or breakage, thereby forming a finished high-density polyethylene film.

[0068] Embodiment three:

[0069] On the basis of the second embodiment, the multi-layer co-extrusion production process of the high-density polyethylene film further comprises the following steps:

[0070] Slitting: Place the shaped high-density polyethylene film on the slitting machine, and then start the slitting machine. After a period of time, the slitting machine will divide the high-density polyethylene film into several groups of equal amounts;

[0071] Inspection: The slit high-density polyethylene film is inspected by the existing inspection device. By observing the values ​​of the inspection device, it is determined whether the production of the fluororesin film meets the standards, and then the fluororesin film that does not meet the standards is processed again;

[0072] Step 8: Packaging: Label the multi-layer composite films that meet the relevant requirements and those that do not meet the relevant requirements after inspection. The films that meet the relevant requirements are packaged and put into the finished product raw material area.

[0073] Comparative Example:

[0074] The difference between this comparative example and Example 1 is that only polyethylene is selected as the main raw material, and only antistatic agent is selected as the auxiliary material; secondly, a single-layer co-extrusion extruder is selected, and step five is removed.

[0075] Experimental example:

[0076] The performance of the high-density polyethylene films produced by the multi-layer co-extrusion production process of the high-density polyethylene films of Examples 1, 2, 3 and the comparative example is tested, and the results are shown in the following table:

[0077] Example Tensile strength(Mpa) Light transmittance (%) Antibacterial rate (%) Heat resistance(℃) Embodiment 1 35.2 96 98.4 104 Embodiment 2 36.5 96 98.7 105 Embodiment 3 37.1 96 99.1 106 Comparative Example 24.9 84 none 94

[0078] As can be seen from the table above, the high-density polyethylene films produced in Examples 1, 2, and 3 are superior to the comparative examples in various performance indicators, especially in terms of antibacterial performance. The films of the examples show extremely high antibacterial rates, which are mainly attributed to the added nano-silver particle antibacterial agent. In addition, since more extrusion units are used in Example 2, the multi-layer structure of the film is more uniform, thereby performing better in tensile strength and tear strength.

[0079] In summary, by using multi-layer co-extrusion technology, high-density polyethylene resins with different properties are combined together, so that the film has better barrier properties, mechanical properties and heat sealing properties while maintaining the original advantages of high-density polyethylene, thus broadening its application range. At the same time, this production process has the advantages of high production efficiency and stable product quality.

[0080] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A multi-layer co-extrusion production process for high-density polyethylene film, characterized in that: The following steps are involved: Step 1: Raw material preparation: Select nylon, polyethylene, acid-modified polyolefin composites, ethylene tetrafluoroethylene polymers, and polytetrafluoroethylene as the main raw materials, and prepare auxiliary materials to improve the processing and use properties of the film; Step 2: Extruder preparation: Select a multi-layer co-extrusion extruder, and preheat and debug the multi-layer co-extrusion extruder; Step 3: Extrusion molding: The prepared main raw materials and auxiliary materials are added into the multi-layer co-extruder respectively, and melted and plasticized by heating and the shearing action of the screw, so that the molten materials converge at the die head to form a melt with a multi-layer structure; Step 4: Stretch and shape: The melt is longitudinally stretched by the mechanical force of extrusion blow molding in the extruder, and simultaneously or laterally stretched by compressed air blowing, and cooled, so that the multilayer composite film is blown into a thin film; Step 5: Corona treatment: Corona treatment is performed on the stretched film; Step 6: Rolling up: The treated film is rolled up by a rolling device to form a finished high-density polyethylene film.

2. The multi-layer co-extrusion production process of a high-density polyethylene film according to claim 1, characterized in that: In step 1, the auxiliary materials include a lubricant, an antistatic agent, an antioxidant and an antibacterial agent.

3. The multi-layer co-extrusion production process of a high-density polyethylene film according to claim 2, characterized in that: The lubricant is polyethylene wax, the antistatic agent is ethylene bisstearamide, the antioxidant is 2,6-di-tert-butyl-p-cresol, and the antibacterial agent is nano silver particles.

4. The multi-layer co-extrusion production process of a high-density polyethylene film according to claim 1, characterized in that: In step 2, the multi-layer co-extrusion extruder includes a plurality of extrusion units, and each extrusion unit is responsible for extruding one material.

5. The multi-layer co-extrusion production process of a high-density polyethylene film according to claim 4, characterized in that: In step three, the die head is a co-extrusion die head having a plurality of feed ports, each of which corresponds to an extrusion unit, to ensure that the raw materials of each layer are uniformly converged at the die head.

6. The multi-layer co-extrusion production process of a high-density polyethylene film according to claim 5, characterized in that: In step 4, the multi-layer co-extrusion extruder is co-extruded by multiple extrusion units, extruded at one die head, and the multi-layer co-extrusion extruder is equipped with a fan and a cooling ring at the die head to cool the multi-layer film in the cooling line, and finally a high-density polyethylene film is obtained.

7. The multi-layer co-extrusion production process of a high-density polyethylene film according to claim 6, characterized in that: In step 4, the cooling method adopts air cooling or water cooling.

8. The multi-layer co-extrusion production process of a high-density polyethylene film according to claim 1, characterized in that: In step five, the corona treatment is operated by applying a high voltage to the film surface to generate a corona discharge phenomenon, thereby forming a fine concave-convex structure on the film surface, improving the surface tension and adhesion of the film, and making it easier to print and laminate.

9. The multi-layer co-extrusion production process of a high-density polyethylene film according to claim 1, characterized in that: In step six, the winding device includes a tension control device to ensure that the film maintains appropriate tension during the winding process to prevent the film from loosening or breaking.

10. A multi-layer co-extrusion production process for high-density polyethylene film according to any one of claims 1 to 9, characterized in that: The following steps are also included: Slitting: Place the shaped high-density polyethylene film on the slitting machine, and then start the slitting machine. After a period of time, the slitting machine will divide the high-density polyethylene film into several groups of equal amounts; Inspection: The slit high-density polyethylene film is inspected by the existing inspection device. By observing the values ​​of the inspection device, it is determined whether the production of the fluororesin film meets the standards, and then the fluororesin film that does not meet the standards is processed again; Step 8: Packaging: After inspection, the multi-layer composite films that meet the relevant requirements and those that do not meet the relevant requirements will be labeled, and the films that meet the relevant requirements will be packaged and sent to the finished product raw material area.

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