Multilayer coextruded polyethylene film processed in down-blowing water-cooling ring film method

Abstract

The invention discloses a multilayer coextruded polyethylene film processed in a down-blowing water-cooling ring film method. The multilayer coextruded polyethylene film comprises a corona disposal layer and a heat seal layer, and can also consist of a core layer, wherein the formula for each layer comprises: 60-95 parts of polyethylene, 5-40 parts of butylene polymer or propylene polymer, 0.005-1 part of anti-blocking agent, 0.005-1 part of slipping agent, 0.005-0.5 part of nucleating agent, and 0-0.5 part of fluorocarbon resin. By introducing sphaerocrystal through adding the butylene polymer or the propylene polymer in the formula, improving the crystallinity under the effect of the nucleating agent, and regulating the microcosmic planeness of the film surface in the present of fluorocarbon resin, the film has both the high composite strength and good anti-blocking property of a composite film and high transparency, can withstand water boiling sterilization at a temperature over 100 DEG C and stewing sterilization at a temperature below 121 DEG C, has low friction coefficient and attractive appearance. The product prepared in the formula reaches the ideal mutual balance among processability, optical property, mechanical property and temperature tolerance, and can be used for mass production with low industrial production cost.

Description

technical field [0001] The invention relates to a polyethylene film, especially a polyethylene film which has excellent optical properties, easy processing, high composite strength, and resistance to boiling sterilization above 100 degrees Celsius and high temperature cooking sterilization below 121 degrees Celsius after being processed by the method of blowing down the water-cooled ring film. Co-extruded polyethylene film. Background technique [0002] The ring film blow molding method is a method of making a film by using an extruder, passing through a ring die, and adopting an inflation film forming process. [0003] At present, in the field of film production, the main film forming methods include casting method and ring film blowing method. [0004] The tape casting method is mainly used to process polypropylene. The advantages of this method are: good flatness of the film and good optical properties. The disadvantages are: high equipment cost, high product cost, diffi...

AI Technical Summary

Problems solved by technology

[0004]Casting method is mainly used to process polypropylene. The advantages of this method are: good film flatness and good optical performance. The disadvantages are: high equipment cost and high product cost , Difficult opening, large friction coefficient, etc., which are the reasons why it has not been widely used in the production process of polyethylene film for composite use in my country

[0005]The production process of ring film blow molding method is mainly divided into two cooling forms: upward blowing cooling and down blowing water cooling. The method of extruding from the machine, forming and extruding through a circular die, and forming a film after air cooling is mainly used to process polyethylene. Polypropylene cannot be processed by this method due to its slow crystallization speed and rapid shear thinning.

Its advantages are: easy film forming and low cost, but the disadvantages are: slow cooling and poor optical properties of the film

In the existing down-blown water-cooled ring film polyethylene formulation, usually the corona layer is polyethylene, the core layer is polyethylene, and the heat-sealing layer includes polyethylene, silicon oxide and erucamide. The problems of the multi-layer co-extruded film obtained by the water-cooled ring film method polyethylene formula are: (1) low breaking strength and poor mechanical properties, (2) inability to corona synchronously, after synchronous corona, the film has poor appearance and low composite strength, Composite film cannot be made, (3) winding is very easy to wrinkle, and cannot be produced on an industrial scale, (4) opening performance is poor, it is difficult to balance opening performance and composite performance at the same time, (5) not resistant to high temperatures above 100 degrees Celsius

Therefore, it cannot be applied to the demanding composite flexible packaging industry

Images