Blowing film technology tips (1)

Blown film technology tips: blown film is actually a kind of film between biaxially oriented film and cast film. The inflation method can also be used to produce biaxially oriented films. As long as the temperature is appropriate and the ratio of inflation ratio and traction ratio is appropriate, the bidirectional orientation degree can be approximately the same. When the blown film is produced, if the drawing speed is too fast and the blow-up ratio is too different, the longitudinal orientation and the transverse orientation may differ too much. The result is the same as the process of uniaxial stretching to produce film split fibers. Low transverse strength, easy to break. The prevention method is to appropriately reduce the traction speed to match the expansion ratio; increase the air volume of the air ring to quickly cool the inflated film, and avoid being stretched orientated at a higher temperature and high elasticity. Take the 80 film blowing machine as an example: (different models have different specifications)
The first part of the feed heating zone is divided into 5 zones:
Rod (diameter 6CM), shell 8, 7CM, 11kw motor (host) drive. It is divided into one, two and three heating zones from the feed inlet.
The next turn is upwards, it belongs to four heating zones, and the parts are called three links, one link three zones, two links outlets, and three links five zones.
The fifth heating zone is the discharging zone, which is turned upward through the 3-port, called the film head, and is the most critical part of the machine. The accessory is a blower.

The second part is the traction area, which blows up and compresses the edges, the total height is about 3 to 5 meters, and the accessory is the air pump.
The third part is the winding area.
Main materials: low pressure polyethylene HPPE mixed with high pressure polyethylene LLDPE mixed materials, low pressure material mainly accounts for about 80%, the more high pressure is added, the better the tension, the disadvantage is that there is no stiffness, too much will cause the blown film to swing back and forth , The blown film is not neatly closed, and even cannot be blown at the end.
Start the film blowing process:
After preheating in the first, second, and third zones, the first zone should be lower, generally around 170 degrees, and the other zones around 200 degrees. If the temperature is high, it will not be able to be sent through the rod, and it will even be burnt and discolored.
Next is the four-zone or three-way zone. A 60 mesh -160 filter screen is placed in the tee to prevent impurities from entering the five zones. The larger the mesh, the finer the mesh, and it can blow thinner and more demanding films, including the transparency of the film, the smoothness of the hand, the tension, etc., But too much and too fine will prevent the material from passing through, and too much will not be blown out. Generally 3-5 sheets are suitable, and the thickness is determined according to the requirements.

When the material reaches the fifth zone, the discharging port becomes a 7cm diameter round sticky paste through the film head, and the temperature of the material is basically stable. The suitability of the entire heating process should be controlled according to the discharging mouth. If it is too high, the film is unstable. , And scorched and discolored, too low to pull the film. The unevenness of the membrane thickness must be adjusted by the membrane head thread.

Shantou Shuangli Machinery focuses on R&DPlastic film blowing machineMachinery manufacturing enterprises, welcome new and old customers to visit us, we will serve you wholeheartedly!

Contact: Yu Hongliang Manager
Phone: 18955651595
Phone: 86-1396-6902200
URL:www.stcmj.net
Address: Jinping District Industrial Park, Jinping District, Shantou City, Guangdong Province, China