Biaxially oriented polypropylene film
日期：2020/9/21 8:32:57 / 阅读： / 来源：本站
Biaxially oriented polypropylene filmTake biaxially stretched polypropylene film as an example.
Biaxially stretched polypropylene film (BOPP) has the advantages of light weight, transparency, non-toxicity, moisture resistance, and water resistance. It has good thermal stability, chemical stability and electrical properties, so it is used in food, candy, cigarettes, tea, medicine It is widely used in packaging of, juice, milk, textiles, etc., as well as the production of electrical adhesive tape. In recent years, the production of BOPP adopts a new seven-layer co-extrusion technology, which enables BOPP to be evenly distributed in the central gas barrier layer with acrylonitrile-butadiene copolymer, effectively blocking oxycarbon, water vapor and other corrosive substances The entry of this product greatly increases the anti-corrosion ability of the packaged objects and prolongs the storage period of the objects. Therefore, people give this BOPP film with a gas barrier layer the reputation of "Packaging Queen". www.handern.com Non-woven equipment
1. Main raw materials
BOPP film is made of isotactic PP as the main raw material, and is made with 3% to 5% of additive masterbatch according to different products and uses. The raw material should be a film-grade PP homopolymer, and should have the following characteristics: ①The melt flow rate is 1.5g/10min～4.0g/10min; ②The isotacticity is 95%～98%; ③The moisture content is <0.03%; ④ Ash content <0.2x10. Additives are auxiliary components for film making, and erucamide type lubricants, ethylenediamine type antistatic agents and antifreeze agents containing silica particles are generally used to improve the surface properties of the product. www.handern.com Non-woven equipment
2. Main equipment and basic process flow
The equipment is mainly manufactured by a professional company of BOPP automatic production line. Companies that can provide complete sets of BOPP equipment technology include Japan's Mitsubishi Heavy Industries (MIT-SUBISHI) and East (TOSHIIBA); France (CELLIER); Germany (BRUCKNER), Lenzing (LENZING) and the United States Marsall (MARSALL), etc. . Among these competitive technologies, Mitsubishi Heavy Industries and Bruckner are more advanced in technology. Mitsubishi Heavy Industries' technology is characterized by tandem twin-screw extrusion and multi-roll cooling molding; Bruckner is known for its multi-machine co-extrusion, two-cylinder filter roll water bath chilling, and the rational use of additives. Mitsubishi Heavy Industries' tandem twin-screw extrusion has good PP plasticization, uniform and stable pressure, small lateral shrinkage of thick sheets, and good tolerances of thick sheets. However, the multi-roll cooling process conditions are narrow, the cooling is slow, and large-scale high-speed production is restricted. Bruckner's multi-machine co-extrusion uses different extruder combinations and matching die heads to produce light film and multi-layer film; adopts double-cylinder filter device, which can replace the filter while producing; adopts large roller internal cooling Adding water bath external cooling, so that the molten material can quickly pass through the crystallization temperature zone and be quenched to room temperature, which is conducive to high-speed large-scale production; using additives to adjust the formula, the product has great variability and good film performance. However, the rapid cooling of the water bath causes shrinkage on both sides of the thick sheet, and the product tolerance is affected. The technologies of Mitsubishi Heavy Industries and Brückner represent two different molding processes today and have achieved coexistence and development. Regardless of the company’s process technology, the production of BOPP film is carried out according to the following basic process, namely PP→extrusion→filter→die head molding→quick cooling casting→thickness measurement→longitudinal stretching→horizontal stretching →Edge trimming→Film thickness measurement→Corona treatment→Rewinding→Aging treatment→Slitting and packaging. www.handern.com Non-woven equipment