Method for manufacturing polymer film

Abstract

The invention relates to a method for manufacturing a polymer film. The method comprises a film forming step and a stretching step, wherein, in the film forming stage, the die gap of the head of an extruder is between 1.6 and 1.8mm, and film bubble cooling parts are arranged at a position close to the extruder outlet and a position which is 1 to 2 meters from the extruder outlet respectively; in the stretching stage, a group of preheat rollers are used for preheating, two groups of stretch roller pairs are used for stretching, and cold and heat alternated molding rollers are used for molding.The method has the characteristics that the film which is manufactured by a unilateral stretching process can be applied in packaging fields of printing, compounding and the like, can be boiled at a high temperature of 135 DEG C, has small vertical tear force and large transverse tear force, and is ensured to be torn straightly.

Description

technical field [0001] The invention relates to a method for manufacturing a polymer film, in particular to a method for producing a polymer film by blow molding and stretching. Background technique [0002] Film is a widely used packaging material in the food industry, and its manufacture mainly uses blow molding and stretch molding processes. Polyolefin (such as polyethylene, polypropylene, polyvinyl chloride, etc.) The film bubble is developed into a piece of film, which is directly sent to the longitudinal stretching machine through the guide roller, and the longitudinal stretching makes the film thinner. Generally, the stretching ratio is 3-7 times. The disadvantage of this manufacturing method is that in the blow molding process, cooling is only provided at the outlet of the extruder head, and the cooling air is blown to the bubble through the built-in or external cooling equipment. For thinner films such as Cooling can meet the requirements, but when the film thickn...

Images