Method for single layer or multilayer coextruding two-way extension polypropylene film and special equipment

Abstract

During the production of two-way extended polypropylene film, the tube extruder extruded polypropylene tube blank is cooled, set in a preheating extending tower and a high temperature setting tower, and wound in a winding system. The special equipment includes blank tube extruder, preheating extending tower, and corona film edge cutting and winding system as well as high temperature setting towercomprising film bubble stabilizing A-shaped plates, heating mechanism and cooling mechanism. The present invention makes it possible to make both single-layered film and multi-layered film, especially superlow temperature blast material with high quality, no surface damage and good longitudinal performance.

Description

1. Technical field [0001] The invention relates to a method for manufacturing polypropylene film and its special equipment, in particular to a method for single-layer or multi-layer co-extrusion biaxially stretched polypropylene film with three bubble tubes and its special equipment. 2. Background technology [0002] The existing single-layer or multi-layer co-extruded biaxially oriented polypropylene film (heat setting, referred to as BOPP film) has three manufacturing methods and corresponding special equipment; flat film sequential stretching method, flat film synchronous stretching method and gun barrel stretching method. [0003] 1. Problems in the flat film successive stretching method: [0004] 1) The equipment process of the flat film successive stretching method adopts longitudinal stretching first and then transverse stretching. The transverse physical properties of the produced products are better than the longitudinal properties, and any packaging film requires ...

AI Technical Summary

Problems solved by technology

[0006] 3) The contact preheating slab and longitudinal contact stretching method limit the use of three-layer co-extruded surface layer heat-sealing materials, let alone use ultra-low temperature heat-sealing materials (heat-sealing materials that are sticky below 105 degrees), thus It limits the development of heat-sealing film to high-speed packaging and low-temperature heat-sealing

[0008] 1) The main equipment and auxiliary equipment have a large investment, with a total investment of more than 400 million yuan, the input-output ratio is unscientific and unreasonable, the production cost is high, and it is not convenient to produce various products, and the equipment occupies a large area

[0009] 2) Although the product quality is very good and the longitudinal physical properties of the film are easy to adjust, the energy consumption of the product is high, which restricts the market application and development of the biaxially oriented polypropylene packaging film produced by the flat film synchronous stretching method equipment system

[0011] 1) At present, the single-layer single-bubble tube down-blowing method can only produce down-blown small-caliber polypropylene packaging film (the vertical and horizontal stretch ratio is about ten times)

[0012] 2) At present, the domestic polypropylene down-blown double-bubble tube stretching method can only produce down-blown polypropylene non-heat setting shrink packaging film (the shrinkage rate cannot be controlled without high temperature setting)

[0013] 3) At present, the most advanced biaxially oriented polypropylene film product (heat setting) produced by the double-bubble tube method in the world has the same performance as the flat film method (sequential stretching and synchronous stretching), using two types of setting equipment and application The corresponding process can be completed: a) The non-heat-sealable film adopts heating plate contact type setting to control the shrinkage rate of the film. To achieve heat-sealability, the film must enter another set of low-temperature coating equipment for low-temperature heat-sealing material coating ; b) The heat-sealing film is non-contact, and the film is held by clips and passed in a hot air oven, and the shrinkage rate of the film is controlled by high temperature setting. sealing material

In order to produce multi-variety (non-heat-sealable, heat-sealable, ultra-low temperature heat-sealable) biaxially oriented polypropylene films with the same performance under the same equipment system and the same process conditions, there is no precedent at home and abroad.

Images