High Speed Extrusion Lamination Compound Machine
High Speed Extrusion Lamination Compound Machine
High speed extrusion lamination compound machine is a special machine for making a film or paper with some other material like PE/ PP/ Metallized PET/ Al foil and Woven PP Sacks etc.high speed extrusion lamination compound machine It has a shaftless unwinder, hydraulic compounding, high efficiency corona and auto-height adjusting extruder etc. This machine is featured at high speed and intelligent operation, coating quality better and waste less.
Some companies have already started production with a variety of materials. One example is Alma Polska Wroclaw, Poland, which installed a BEX 75-mm extruder in February for making white ABS and PS sheet from 1 to 6 mm thick for refrigerator liners at a speed of 3000 lb/hr. Another pioneer is Huhtamaki in France, which is running a cast coex barrier PP line with a BEX 80-mm extruder at 800 rpm and producing 880 lb/hr of sheet.
The big challenge is achieving stable melt temperatures at such high speeds. This requires a screw with higher flight depth to compensate for the lower melting zone, and barrel heating or air cooling to control high temperatures in the feed zone. Screws also have to be modified to resist the high forces generated by the faster rotational speed. Many producers are finding that the use of a helical screw with a longer melt zone is critical to stable melt flow at high speeds.
Another issue is reducing melt flow and viscosity for improved adhesion between the substrates. This may require blending in blown film resins with tougher, metallocene catalysts such as m-VLDPE and m-ULDPE to reduce viscosity. It also might be necessary to use a thinner, more fluid coating formulation or increase the pressure on the chill rolls to force melt out more quickly.
In adhesive lamination, a low coefficient of friction (COF) between the substrates is essential for a strong bond. This can be achieved by adding a slip agent or using a matte chill roll to reduce inner layer contact. In addition, a stronger LDPE or other blown film sealant can improve the strength of an adhesive lamination.
Other issues include the temperature of the substrates and the ability to cool them rapidly at high speeds, which is possible only with newer, more efficient machines. In addition, there is the question of whether the film can be made with a lower melt temperature than in a conventional extruder to avoid excessive shrinkage and warping of the substrate.
Some companies are trying to solve these problems by modifying their equipment, adding a slip agent or using a more fluid coating formulation. In some cases, these adjustments might not address the root cause of the problem. For example, if the initial structure of the laminate is too asymmetrical, heat and subsequent cooling can result in curl as the asymmetrical side cools faster than the other. In that case, a solution might be to move the extruder carriage closer to the primary substrate side or to blend the LDPE with stiffer metallocene catalyst resins.