PE protective film is one of the days we common plastic products, it is by the rolling process, extrusion process, blow molding process to produce, such as film blowing method is to squeeze plastic material to the raw materials by extruder melting into a thin tube, and then blow it with compressed air, hot through cooling stereotypes of film products.
Blow molding film its primary use of the material: LDPE, HDPE, LLDPE, EVA, PVC, PP, PS, PA, etc.
Polyethylene blown film after molding process of material through the plasticizing extruder, forming tubular to blow molding, cooling, traction, coiling.
In blown film forming process, on the basis of extrusion and drawing has a flat of different direction under the blow, blow, blow three methods, it is a common molding process also have special blow molding, squeezing method as above, let's see what is the difference between these methods.
On the flat extrusion blowing method 】
This method is to use crosshead, namely the nose discharging direction and extruder straight, extrusion tube bad upward, traction to a certain interval, the herringbone powder gathering, the crowded tube from the bottom of the introduction of compressed air to blow it into bubble tube, and by how much compressed air volume to control its lateral size, the traction speed control longitudinal size, bubble tube by cooling shapes can get blown film.
Is suitable for blowing method of the primary types of plastic PVC, PE, PS, HDPE protective film.
Under the flat extrusion blowing method 】
The method using the crosshead, bubble tube from the head below the process under the said flat extrusion blowing method, this method is particularly suitable for low viscosity material and requirements of transparent plastic thin film.
Such as PP, PA, PVDC (
Flat extrusion method of blowing 】
The use and extruder screw concentric straight head, bubble on the surface of the tube and the nose center line at the same level process called flat extrusion blowing method, the law is only applicable to blowing small diameter thin film products, such as LDPE, PVC, PS membrane, flat blow method is also applicable to heating shorten the fruit of the film.
All three of these processes have their own defects, compared in table process merits defects on the flat extrusion blow bubble tube on the cooling pipe, traction safe cover an area of an area small, convenient to easily produce large diameter, thickness of the thicker protective film factory request high liquidity, high cost is not suitable for processing large plastic for protective film cooling, low production efficiency of the blow to produce protective film cooling, high energy efficiency processing liquidity larger plastic extruder higher off the ground, convenient operation does not produce unfavorable thinner coating with flat pressed flat nose blowing as the center, brief structure and protective film thickness is uniform operation is convenient, simple led film blowing ratio can not suitable for larger processing of big diameter, relative density of protective film covers an area of big bubble tube cooling slowly, not suitable for processing large liquid plastic.