Professional Plastic Packaging Machine Manufacturer - Bonada Machinery
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Professional Plastic Packaging Machine Manufacturer - Bonada Machinery
Technology theories comparison:
Casting film is non stretch、non orientation chill-cast plastic film after melt material casting and sudden chill, without obvious orientation structure.
Extrusion film commonly have single direction and double directions stretch types, double directions stretch is more popular technology in recent years.
The general theory of double directions stretch is: high polymer raw materials firstly heated and extruded into thick sheet by extruder, then, at appropriate temperature range (beyond glass transition melting point temperature), do certain multiple stretching on longitudinal and transverse sides by stretch machine, the molecular chain orientation in parallel to the plane of the membrane and orderly arrangement, then do heating to finalize the design when the film is in stretched form, make the orientation of macromolecule structure fixed, cooling and following treatment forming film.
Blown film commonly is made by extrusion blowing technology, material plastication、 extrusion, forming film bubble perform, blowing、cooling、taking up、rewinding.
Blown film has orientation.
As the above 3 kinds different film forming technologies, the produced film have Significantly different conductivity; and, compare to non stretch film, the stretch film barrier character is better, gas permeability decrease, optical performance、transparency degree and surface glossiness, thickness even uniformity better.
Application field comparison: (take CPP、BOPP and ordinary PP film for example)
CPP:transparency、softness、barrier character and good mechanical adaptability, high temperature steaming and boiling resistance (temperature is above 120℃)、low temperature heat sealing (temperature is not beyond125℃).
Mainly applied as inside base material of composite packages for foods、candies、cooked food、frozen foods、condiment、soup bases etc,could prolong the food quality grantee period, much beautiful appearance, also could be used for stationary products outside layer、interlayer and auxiliary films such as loose leaf & labels of photos、collectibles.
BOPP:splendid printing character, could be laminated with paper、PET and other base material, good clarity and glossiness、great Ink absorption and layer adsorption force、high stretch force、good grease barrier function、low static electricity performance etc. It has wide application in printing & laminating field,as well, often used as package material for tobacco etc aspects.
Blow film PP:simple technology, low cost, optical performance slightly lower than CPP and BOPP, mainly applied for snacks、breads、textile products、documents folder、CD covers、sport shoes etc package.
And, the BOPP and OPP, after laminating, the characters will increase, the application will be wider, has moisture resistance、transparency features, could be applied for packing dry foods such as peanuts、fast food、chocolate、snacks etc. In recent years, inChina, plastic films types are increasing, and they have different advantaged features, with the continually increasing of technology, package films have bright prospect.
