Production process of high-performance polyethylene film

Abstract

The invention provides a production process of a high-performance polyethylene film. The production process comprises the steps of raw material pretreatment, mixing and stirring, melt extrusion, tape casting, two-way stretching, cooling treatment, surface modification, trimming and rolling, finished product detection and the like. According to the scheme, by optimizing the raw material ratio and the pretreatment process, it is ensured that the raw materials are evenly mixed and thoroughly dried, bubbles and impurities generated after film forming are avoided, and the appearance and basic performance of the film are improved. The scheme has the advantages of a full-process continuous integration process, strict finished product detection and the like, ensures the production stability and the product quality consistency, is high in finished product percent of pass, and is suitable for industrial large-scale production.

Description

Technical Field

[0001] This invention relates to the field of film production, and more particularly to a production process for high-performance polyethylene film. Background Technology

[0002] Polyethylene film is widely used in packaging, agriculture, electronics, and other fields due to its advantages such as light weight, chemical resistance, and low cost. However, traditional polyethylene film production processes suffer from several drawbacks. Uneven raw material mixing can lead to fluctuations in film performance, and incomplete drying can cause air bubbles after molding, affecting appearance and strength. Insufficient temperature control precision during extrusion molding can result in incomplete plasticization of the raw materials, and poor matching of subsequent stretching process parameters can lead to disordered molecular orientation, thereby reducing the film's tensile strength and thermal stability. Furthermore, traditional films have poor surface adhesion, making it difficult to meet the requirements of subsequent printing and lamination processes. The lack of standardized performance criteria in finished product testing also results in inconsistent product quality. Summary of the Invention

[0003] The purpose of this invention is to overcome the above-mentioned problems and provide a production process for high-performance polyethylene film. The polyethylene film produced by this process has advantages such as high tensile strength and good thermal stability.

[0004] To achieve the above objectives, the present invention provides a production process for high-performance polyethylene film, which includes the following steps: A. Raw material pretreatment: Drying and impurity removal treatment is carried out on the composite raw materials to remove moisture and impurities in the raw materials to avoid the generation of bubbles or impurity defects in subsequent processing. B. Mixing and stirring: The pretreated raw materials are homogenized and stirred at high temperature using a twin-screw mixer to ensure that each component is evenly dispersed. C. Melt extrusion: The uniformly mixed raw materials are fed into a single screw extruder, and the heating temperature is set to fully melt and plasticize the raw materials to form a stable molten material flow; D. Casting: After the molten material is extruded through the T-die, it is bonded to the surface of a high-precision cooling roller for rapid cooling and shaping, forming a thick sheet substrate with uniform thickness. E. Biaxial stretching: The thick substrate is stretched longitudinally and laterally in sequence, and the molecular orientation structure of the film is improved by precise temperature control and rate adjustment. F. Heat setting: The stretched film is sent into a heat setting oven for heat preservation treatment to eliminate internal stress and stabilize the film size. G. Cooling treatment: A multi-stage cooling method is adopted to quickly reduce the film temperature and avoid performance fluctuations caused by the film reheating after heat setting. H. Surface modification: The cooled film surface is activated by plasma treatment technology to improve the film surface adhesion and compatibility with subsequent processing. I. Trimming and winding: The edges of the surface-modified film are trimmed, and irregular edge material is removed before being wound into film rolls by a winding machine; J. Finished Product Inspection: The physicochemical properties and appearance quality of the wound film are tested, and qualified finished products are selected.

[0005] In one or more embodiments, in step A above, polyethylene resin, reinforcing agent, heat-resistant modifier and antioxidant are mixed in a mass ratio of 85-92:3-8:2-5:0.5-1.5 and dried in a drying oven at 60-80°C for more than 2 hours.

[0006] In one or more embodiments, in step B above, a twin-screw mixer is used, the stirring speed is 400-500 r / min, the stirring temperature is controlled at 100-120℃, and the stirring time is 30-60 minutes, resulting in a raw material mixing uniformity ≥95%.

[0007] In one or more embodiments, in step C above, a single-screw extruder is used, with the temperature set at 190-210°C and the screw speed at 80-100 r / min.

[0008] In one or more embodiments, in step D above, after the molten material is extruded through a T-die, it is bonded to the surface of a cooling roller. The temperature of the cooling roller is 20-40°C, and the material cooling rate is 5-10°C / s, forming a thick sheet substrate.

[0009] In one or more embodiments, in step E above, biaxial stretching includes longitudinal stretching and transverse stretching, wherein the longitudinal stretching temperature is 90-110°C and the stretching ratio is 2.5-4.0 times; the transverse stretching temperature is 100-120°C and the stretching ratio is 3.0-5.0 times.

[0010] In one or more embodiments, in step F above, heat setting is performed in an oven at a temperature of 120-140°C for 10-20 seconds, and the heat shrinkage rate of the film after heat setting is ≤3%.

[0011] In one or more embodiments, in step H above, the plasma power is 100-300W, the processing time is 5-15 seconds, the contact angle of the thin film surface after processing is ≤60°, and the surface tension is ≥38mN / m.

[0012] In one or more embodiments, in step J above, the finished product inspection includes thickness inspection, tensile strength inspection and elongation at break inspection. The finished film thickness is 5-50 μm with a thickness deviation of ≤±2%; longitudinal tensile strength ≥25 MPa, transverse tensile strength ≥22 MPa; longitudinal elongation at break ≥300%, transverse elongation at break ≥280%.

[0013] Compared with the prior art, the advantages of this invention are: by optimizing the raw material ratio and pretreatment process, it ensures uniform mixing and thorough drying of raw materials, avoiding bubbles and impurities after film formation, and improving the appearance and basic properties of the film. This solution has advantages such as a fully continuous integrated process and rigorous finished product testing, ensuring production stability and product quality consistency, resulting in a high finished product qualification rate, and making it suitable for large-scale industrial production. Attached Figure Description

[0014] Figure 1 This is a flowchart of the polyethylene film production process of the present invention. Detailed Implementation

[0015] To enhance understanding of the present invention, the present invention will be further described in detail below with reference to embodiments and accompanying drawings. These embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0016] Please refer to the appendix. Figure 1 This application provides a production process for high-performance polyethylene film, which includes the following steps: A. Raw material pretreatment: Mix polyethylene resin, reinforcing agent, heat-resistant modifier and antioxidant in a mass ratio of 90:6:3:1 and dry in a drying oven at 70℃ for 3 hours; B. Mixing and stirring: A twin-screw mixer was used with a stirring speed of 450 r / min, a stirring temperature of 110℃, and a stirring time of 50 minutes, resulting in a raw material mixing uniformity of 97%.

[0017] C. Melt extrusion: A single-screw extruder is used, with the temperature set at 200℃ and the screw speed at 100r / min.

[0018] D. Casting: After the molten material is extruded through a T-die, it is bonded to the surface of a cooling roller. The temperature of the cooling roller is 3℃, and the material cooling rate is 8℃ / s, forming a thick sheet substrate.

[0019] E. Biaxial stretching: including longitudinal stretching and transverse stretching. The longitudinal stretching temperature is 100℃ and the stretching ratio is 3.0 times; the transverse stretching temperature is 110℃ and the stretching ratio is 4.0 times.

[0020] F. Heat setting: Heat setting is carried out in an oven at a temperature of 130°C for 15 seconds. The heat shrinkage rate of the film after heat setting is 2.5%.

[0021] G. Cooling Treatment: A multi-stage cooling method is employed to rapidly reduce the film temperature, preventing performance fluctuations caused by film re-temperature after heat setting. Specifically, a multi-stage cooling method combining air cooling and water cooling is used to rapidly reduce the film temperature, avoiding performance fluctuations caused by film re-temperature after heat setting. First, the film is air-cooled at 20-30℃ for 10-15 seconds, then water-cooled at 10-15℃ for 5-10 seconds. After cooling, the film temperature drops to room temperature ±5℃. This multi-stage cooling method balances cooling efficiency and film morphological stability, ensuring stable film performance.

[0022] H. Surface modification: The plasma power is 200W, the treatment time is 10 seconds, the contact angle of the treated film surface is 55°, and the surface tension is 40mN / m.

[0023] I. Trimming and winding: The edges of the surface-modified film are trimmed, and irregular edge material is removed before being wound into film rolls by a winding machine; J. Finished Product Inspection: This includes thickness inspection, tensile strength inspection, and elongation at break inspection. The finished film thickness is 20μm with a thickness deviation of ±1.5%; longitudinal tensile strength is 27MPa, transverse tensile strength is 24MPa; longitudinal elongation at break is 320%, and transverse elongation at break is 300%.

[0024] The above description is only a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. Any equivalent modifications or changes made by those skilled in the art based on the content disclosed in the present invention should be included within the scope of protection set forth in the claims.

Claims

1. A production process for high-performance polyethylene film, characterized in that, Includes the following steps: A. Raw material pretreatment: Drying and impurity removal treatment is carried out on the composite raw materials to remove moisture and impurities in the raw materials to avoid the generation of bubbles or impurity defects in subsequent processing. B. Mixing and stirring: The pretreated raw materials are homogenized and stirred at high temperature using a twin-screw mixer to ensure that each component is evenly dispersed. C. Melt extrusion: The uniformly mixed raw materials are fed into a single screw extruder, and the heating temperature is set to fully melt and plasticize the raw materials to form a stable molten material flow; D. Casting: After the molten material is extruded through the T-die, it is bonded to the surface of a high-precision cooling roller for rapid cooling and shaping, forming a thick sheet substrate with uniform thickness. E. Biaxial stretching: The thick substrate is stretched longitudinally and laterally in sequence, and the molecular orientation structure of the film is improved by precise temperature control and rate adjustment. F. Heat setting: The stretched film is sent into a heat setting oven for heat preservation treatment to eliminate internal stress and stabilize the film size; G. Cooling treatment: A multi-stage cooling method is adopted to quickly reduce the film temperature and avoid performance fluctuations caused by the film reheating after heat setting. H. Surface modification: The cooled film surface is activated by plasma treatment technology to improve the film surface adhesion and compatibility with subsequent processing. I. Trimming and winding: The edges of the surface-modified film are trimmed, and irregular edge material is removed before being wound into film rolls by a winding machine; J. Finished Product Inspection: The physicochemical properties and appearance quality of the wound film are tested, and qualified finished products are selected.

2. The production process of a high-performance polyethylene film according to claim 1, characterized in that: In step A above, polyethylene resin, reinforcing agent, heat-resistant modifier and antioxidant are mixed in a mass ratio of 85-92:3-8:2-5:0.5-1.5 and dried in a drying oven at 60-80℃ for more than 2 hours.

3. The production process of a high-performance polyethylene film according to claim 1, characterized in that: In step B above, a twin-screw mixer is used, with a stirring speed of 400-500 r / min, a stirring temperature controlled at 100-120℃, and a stirring time of 30-60 minutes, resulting in a raw material mixing uniformity of ≥95%.

4. The production process of a high-performance polyethylene film according to claim 1, characterized in that: In step C above, a single-screw extruder is used, with the temperature set at 190-210℃ and the screw speed at 80-100 r / min.

5. The production process of a high-performance polyethylene film according to claim 1, characterized in that: In step D above, the molten material is extruded through a T-die and then adhered to the surface of a cooling roller. The temperature of the cooling roller is 20-40℃, and the material cooling rate is 5-10℃ / s, forming a thick sheet substrate.

6. The production process of a high-performance polyethylene film according to claim 1, characterized in that: In step E above, biaxial stretching includes longitudinal stretching and transverse stretching. The longitudinal stretching temperature is 90-110℃ and the stretching ratio is 2.5-4.0 times. The transverse stretching temperature is 100-120℃ and the stretching ratio is 3.0-5.0 times.

7. The production process of a high-performance polyethylene film according to claim 1, characterized in that: In step F above, heat setting is carried out in an oven at a temperature of 120-140℃ for 10-20 seconds, and the heat shrinkage rate of the film after heat setting is ≤3%.

8. The production process of a high-performance polyethylene film according to claim 1, characterized in that: In step H above, the plasma power is 100-300W, the treatment time is 5-15 seconds, the contact angle of the thin film surface after treatment is ≤60°, and the surface tension is ≥38mN / m.

9. The production process of a high-performance polyethylene film according to claim 1, characterized in that: In step J above, the finished product inspection includes thickness inspection, tensile strength inspection and elongation at break inspection. The thickness of the finished film is 5-50μm, and the thickness deviation is ≤±2%; the longitudinal tensile strength is ≥25MPa, the transverse tensile strength is ≥22MPa; the longitudinal elongation at break is ≥300%, and the transverse elongation at break is ≥280%.

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