WO-2026092480-A1 - ANTI-ULTRAVIOLET HIGH-STRENGTH POLYETHYLENE FILM AND PREPARATION METHOD THEREFOR

Abstract

In the present invention, during ethylene polymerization, carbon black is added for in-situ polymerization to generate a carbon black-modified polyethylene raw material, the carbon black-modified polyethylene raw material is then processed into a polyethylene base film by means of a solid-state molding process, and the base film undergoes ultra-high ratio stretching to prepare an anti-ultraviolet high-strength polyethylene film. In the present invention, the carbon black is added in situ during the polymerization of an ethylene monomer, enabling more uniform dispersion of the carbon black in polyethylene powder without increasing the cost of raw material preparation. The present invention does not require additional high-temperature melting and high-speed mixing processes, effectively preventing molecular chain breakage, and preserving the integrity of polyethylene molecular chains to the greatest extent, thereby facilitating the achievement of high strength of polyethylene films.

Inventors

• SANG, TIAN
• Ma, Yuqian
• MA, Junying
• XU, Xiaokang
• QIAO, Xiaoyong

Assignees

• 郑州中远防务材料有限公司

Dates

Publication Date

20260507

Application Date

20251029

Priority Date

20241101

Claims (7)

1. A UV-resistant high-strength polyethylene film, characterized in that the UV-resistant high-strength polyethylene film comprises polyethylene, wherein the viscosity-average molecular weight of the polyethylene is not less than 500,000, the film further comprises carbon black, the carbon black content is 0.1-2.0 wt%, the thickness of the film is less than 100 μm, the strength is greater than 15 g/d, and the primary particle size of the carbon black is less than 35 nm.
2. According to claim 1, the UV-resistant polyethylene high-strength film is characterized in that the side lamellar size of the film is 90.133nm-152.319nm.
3. According to claim 1, the high-strength polyethylene film with UV resistance is characterized in that the film is subjected to accelerated UV aging test according to GB/T 16422.3-2022 "Laboratory Light Source Exposure Test Method for Plastics", and the strength of the high-strength polyethylene film decreases by no more than 10% after 500 hours of exposure.
4. A method for preparing a UV-resistant high-strength polyethylene film, characterized by comprising the following steps: 1) A certain amount of carbon black is added to an organic solvent and dispersed evenly. A co-catalyst and a catalyst are added, and ethylene is introduced to carry out a polymerization reaction under certain conditions to generate carbon black-modified polyethylene raw material in situ. 2) The polyethylene raw material obtained in step 1) is processed into a polyethylene-based film using a solid-state molding process; 3) The base film obtained in step 2) is subjected to super-stretching to obtain a UV-resistant polyethylene high-strength film.
5. The method for preparing UV-resistant high-strength polyethylene film according to claim 4 is characterized in that the solid forming process is hot pressing, molding, rolling, or pressing with a steel strip press.
6. A multilayer composite article for bulletproof applications, the article comprising the UV-resistant polyethylene high-strength film as described in any one of claims 1-3.
7. A product comprising the UV-resistant high-strength polyethylene film of claims 1-3 and/or the UV-resistant high-strength polyethylene film prepared according to the preparation method of claim 4, wherein the product is selected from architectural textiles, ropes, fishing lines and nets, cargo nets, straps, and restraints, gloves and other protective clothing used in transportation and aviation.

Description

A UV-resistant high-strength polyethylene film and its preparation method Technical Field This invention belongs to the field of polymer material processing, specifically relating to a UV-resistant high-strength polyethylene film and its preparation method. Background Technology Polyethylene is a common general-purpose plastic widely used in various fields. The application of carbon black in polyethylene can: (1) improve the mechanical properties of polyethylene materials, increase their hardness, strength and stiffness, reduce their ductility and improve their impact resistance; (2) improve the heat resistance and weather resistance of polyethylene materials, making them more suitable for outdoor use; (3) improve the electrical conductivity of polyethylene materials, making them more suitable for electronic products and conductive materials; (4) be used as a colorant in the manufacture of black polyethylene products. Patents CN106093614A and CN114479256A respectively prepared carbon black masterbatch for polyethylene pipes with a carbon black content of 25-50% and carbon black masterbatch for polyolefins with a carbon black content of 40-50% by internal mixer melt blending granulation and single screw melt extrusion granulation. Patent CN105086079B describes the preparation of a modified weather-resistant high-density polyethylene black sheath material for bridge cables with a carbon black content of approximately 2.6% using a twin-screw melt extrusion granulation method with carbon black masterbatch. Patent CN109593248A and patent CN111154164A respectively prepared antistatic ultra-high molecular weight polyethylene composite materials with a carbon black content of 1-10% and ultra-high molecular weight polyethylene composite materials with a carbon black content of 0.5-1.5% by high-speed mixing-high temperature molding and single screw melt extrusion methods, respectively. In the latter, carbon black is mainly used as a nano-nucleating plasticizer to regulate the crystallization properties of ultra-high molecular weight polyethylene. The aforementioned patents cover carbon black applications in polyethylene or polyolefin masterbatches, polyethylene sheathing materials, and polyethylene composites (sheets or pipes). The application of carbon black in polyethylene films has not yet been reported. Furthermore, in order to ensure the carbon black is dispersed as uniformly as possible in the matrix polymer, the aforementioned patents employ melt extrusion blending or high-speed mixing-high-temperature molding methods. The high shear and high temperature during processing inevitably cause a certain degree of breakage in the molecular chains of the matrix polymer, thereby reducing the strength of the product. Summary of the Invention To overcome the shortcomings of existing technologies and to ensure that carbon black can be uniformly dispersed in polyethylene while ensuring that the polyethylene molecular chains are not damaged during processing, this invention discloses a UV-resistant high-strength polyethylene film and its preparation method. To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention provides a UV-resistant high-strength polyethylene film, characterized in that the UV-resistant high-strength polyethylene film comprises polyethylene, wherein the polyethylene viscosity-average molecular weight is not less than 500,000, the film further comprises carbon black, the carbon black content is 0.1-2.0 wt%, the thickness of the film is less than 100 μm, the strength is greater than 15 g/d, and the original particle size of the carbon black is less than 35 nm. Furthermore, the viscosity-average molecular weight of the polyethylene raw material is preferably not less than 1 million, and more preferably not less than 1.5 million. Furthermore, the carbon black content in the high-strength polyethylene film is preferably 0.2-1.5%, more preferably 0.4-1.0%. If the carbon black content is too high, it will affect the stability of the film during processing; if the carbon black content is too low, the UV resistance will be significantly reduced. Furthermore, the thickness of the high-strength polyethylene film is preferably less than 50 μm, more preferably less than 30 μm. Furthermore, the strength of the high-strength polyethylene film is preferably greater than 20 g/d, more preferably greater than 25 g/d. Furthermore, by measuring using ASTM D3849-07 (2011), the primary particle size of carbon black in the high-strength polyethylene film is preferably less than 30 nm, more preferably less than 25 nm. It was observed that the smaller the primary particle size of carbon black, the better the UV resistance of the high-strength polyethylene film. Furthermore, the side lamellar size of the high-strength polyethylene film is 90.133 nm-152.319 nm. During polymerization, the introduction of carbon black increases the side lamellar size of the polyethylene