A kind of large-area ultra-high molecular weight polyethylene ultra-thin film and preparation method thereof

Abstract

The invention relates to a large-area ultra-thin ultra-high molecular weight polyethylene film and a preparation method thereof, belonging to the field of polymer processing. The invention provides a method for preparing a large-area ultra-high molecular weight polyethylene ultra-thin film. The preparation method comprises the following steps: 1) Stirring and melting polyultra-high molecular weight polyethylene, a solvent and an antioxidant to form a uniform suspension ; 2) The suspension is extruded or banburyed, and then pressed to form a gel film; 3) The obtained gel film is stretched, annealed, extracted and dried to obtain a large-area ultra-high molecular weight polyethylene film. The invention provides a method for preparing a large-area ultra-thin ultra-high molecular weight polyethylene film, which can obtain a large-area ultra-thin ultra-high molecular weight polyethylene film with a thickness of 70-200 nanometers and an area ≥ 0.6 square meters, and the obtained film Has high strength and stability.

Description

technical field [0001] The invention relates to a large-area ultra-thin ultra-high molecular weight polyethylene film and a preparation method thereof, belonging to the field of polymer processing. Background technique [0002] The current methods for preparing polyolefin microporous membranes mainly include melt stretching method (dry method) and thermally induced phase separation method (wet method). When preparing polyolefin microporous membranes by the dry method, although the equipment is simple, the cost is low, and the porosity is high, the shape of the pores is irregular and the control of the pore size is poor; the wet method is easier to control the film formation process and can prepare different morphologies. microporous structure. The invention avoids the disadvantages of the existing wet method film production, and performs process replacement and optimization to obtain a large-area ultrathin polyolefin microporous film. [0003] The existing wet method for p...

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Problems solved by technology

[0003] The existing wet method for preparing polyolefin microporous membranes usually adopts extruder extruding technology to prepare gel membranes, and carries out bidirectional synchronous stretching or unidirectional asynchronous stretching to the gel membranes to prepare microporous membranes. There are many defects in the method: because the extruded gel film is the precursor of the stretched film, whether the internal structure of the gel film is uniform seriously affects the subsequent preparation of the film, and the extrusion method inevitably causes orientation in the gel film, and its The source of orientation is usually near-melt state stretching and film collection curling process, the resulting orientation is usually an uncontrolled orientation produced in a non-isothermal process, the efficiency and effect of chain orientation are not ideal, resulting in many defects in the film , which in turn causes the film to break during stretching or the final stretched film to be thick and uneven in thickness

In addition, with the extrusion method, due to the limited size of the die, the cost of replacement is high, so it is difficult to prepare a gel film with a large size, and thus it is impossible to prepare an ultra-thin polyolefin microporous film at the square meter level;

[0004] For the stretching process, when bidirectional simultaneous stretching, the middle area of ​​the film is weak, easy to break when stretching, the film is thicker, and the failure rate is high

Unidirectional asynchronous stretching not only makes it difficult to achieve isotropic orientation of the stretched film, but also shows significant differences in structural properties between batches

The process is time-consuming and laborious, and causes a lot of waste of materials, so it is not suitable for industrial scale-up

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