Dynamic die surface coating. Applied to making the perfect plastic film.
More demanding needs in industrial applications have led to new and improved plastic resins and production processes. One of the largest applications in polymer processing is films. Those made from polyolefin resins like LDPE, LLDPE or mLLDPE are used in several industries, such as packaging, agriculture, medical, and automotive.
Avoid processing defects
The resin and the production method used can lead to product defects – including melt fracture, die build-up, interfacial instability and gel formation. You can eliminate or reduce the risk using 3M™ Dynamar™ Polymer Processing Additives (PPA).
A PPA creates a dynamic, temporary fluoropolymer coating on the die surface. This gives a low surface energy interface between the metal wall and the molten polymer stream, preventing drag and allowing the melt to slip through the die more easily.
Stresses are reduced in the die and consequently melt fracture is eliminated. In addition, the lowered apparent viscosity allows the polymer melt to flow more freely through the die and reduces pressure.
Eliminate surface fractures
Adding a PPA to an LLDPE extrusion process eliminates surface melt fracturing. Die pressure and extrusion motor torque are reduced. The processing window is increased, leading to a potential reduction in extrusion process temperatures, an increase in extrusion output, a delay to the onset of die build-up at the die lip, increased flexibility in die geometry, and the use of higher viscosity polymers.
3M™ Dynamar™ Polymer Processing Additives (PPAs) are fluoropolymer-based additives used in the extrusion of various thermoplastic polymers to improve end product quality and output. This could be blown and cast film, pipes, sheets, cables, compounding, extrusion blow moulding, monofilaments, tapes or fibres.
Just one example of how PPAs have been widely adopted is the film processing industry. For many years PPAs have been improving the processing of high performance polyethylene such as linear low density polyethylene (LLDPE, mLLPDE) by reducing their apparent viscosity.
Any continuous extrusion process can be optimized by using PPA. Typical benefits, depending on resin, formulation and process, are:
• Reduction of die build-up
• Pressure reduction
• Faster colour changeover
• Energy savings
• Better surface quality
Our technical specialists will work with you on process and output improvement. The following applications may benefit from PPA:
• Sheet extrusion
• PP artificial grass
• PP carpet backing
• Cable extrusion
• Polyamide black compounds
• Polyamide barrier film
• Wood plastic composites (WPC)
Plastic has largely replaced metal, concrete and clay composites in pipe production. Which polymer to use – HDPE, MDPE, LLDPE, PP or PVC – will depend on whether the pipe is to be used for high pressure water or gas, underfloor heating, drainage, irrigation or sewerage, but each can suffer from defects during the manufacturing process. Problems relate to overall pipe dimensions, rheological behaviour of the polymer, and the presence of additives such as carbon black and pigments. Process issues include head pressure, die deposit, and surface defects. All can be eliminated or reduced by adding PPA at levels from 250 ppm up to 1000 ppm.