Each step of polymer processing consumes energy- particularly molding and extrusion that need a high energy for plasticization, pressure increase, heating and cooling, and mechanical work. Polymeric Processing Aids improve the flow behaviour, energy efficiency, end product quality and productivity, contributing cost saving, energy saving and waste reduction. PPAs improve quality of end products and reduce energy requirements of polymer processing. PPAs are not easily removable and, very often have interesting collateral effects such as ease of release, lower friction coefficients, plasticizing effects, impact enhancement. Fluorinated additives are a group of polymer processing aids to improve the processability of high molecular polymers. They are distinguished into external and internal lubricants, characterized by the compatibility or incompatibility with the base polymer. Conventional PPAs have been used for a very long time, including Polyethylene waxes, Modified polyethylenes, Polypropylenes, Metallocene polyolefins, Liquid polymers Innovative PPAs use Fluoropolymers, Siloxane or silicone masterbatches or powders, low viscosity polymers such as CBT or LCP and others, Hyperbranched processing aids (HBPAs), polymeric esters.
Some of the majr fluoropolymer grades are Daikin DA-810 and DA 310ST, Viton Z-100 and Z-200 from DuPont, Dynamar from Dyneon (3M Company). Some of the newer developments in PPA include:
EXCEREX is a high performance polymer processing aid. It is an innovative olefin oligomer, with a narrow molecular weight distribution, manufactured with Mitsui Chemical's leading edge metallocene catalysis technology. It acts to reduce torque in the extruder and thereby allows for an increase in screw speed and simultaneously permits operating at a lower barrel temperature. The end result is increased output, reduced heat defects (scorching) and shortened cooling cycles while maintaining finished product properties. All of this is achieved with only a small amount added as a dry blend to your resin feed.
Arkema’s Kynar Flex® PPA are PVDF based additives designed to aid in extrusion processes of thermoplastic resins. They can be used in blown film, cast film, blow molding, wire and cable jacketing, pipe and tube extrusion, and extruded fiber processes. When used at very low levels of 100–1000 ppm, it can provide benefits to a wide range of resins, particularly LLDPE, mLLDPE, LDPE, HDPE and PP. It helps in elimination of melt-fracture (sharkskin), reduction of die build-up, lower die pressure, increased output, reduced energy consumption, faster start-up and changeover time, lower processing temperatures, improved product appearance and physical properties.
Solvay’s offerings include Solef® 11010 PVDF and Tecnoflon® NM. Solef® 11010 PVDF is a typical thermoplastic material used as an additive in order to offer unique benefits to polymer resins, such as the elimination of melt fracture and the reduction of die buildup. Extrusion characteristics are greatly improved by its use. It offers in combination with a total fluorine content of 61%, excellent performance in many application areas as an attractive cost/performance solution. Tecnoflon® NM is a fluoroelastomer copolymer used as an additive in order to offer unique benefits to polymer resins, such as the elimination of melt fracture and the reduction of die buildup. The most common fluoropolymers which improve the processability of polymers are based on hexafluoropropylene (HFP) and vinylidenfluoride (VDF) monomers. It is based on an elastomeric structure, is an enriched, high value polymer with a maximum level of active fluorinated components. It delivers outstanding performance at even very low concentration levels. In addition to its use in traditional processing aid applications, Tecnoflon NM is the preferred candidate for sophisticated solutions to serve more demanding processing conditions. Both are available in a free flowing powder form, are easy to handle and to dose accurately in masterbatch and/or polymer resin benefits of solef and techno: The product family of fluorinated additives is an individual group of materials offering unique benefits, in particular, for the elimination of melt fracture and the reduction of die buildup for polymer resins. Due to their incompatibility with the majority of polymers and their fast movement in the molten flow, they build a thin coated layer on the metal surface of the die leading to a direct improvement of the processability of the extruded polymers (stabilization of flow instabilities). As a direct advantage, they offer the following benefits: Depending on the processing environment, a final concentration from 200-1000 ppm is sufficient to achieve the desired performance. They are good candidates as processing aids in addition to their major use in mLLDPE blown film applications and in other types of processing methods.
Daikin, a leading supplier of fluoropolymers’ polymer processing aids (PPA) has DA-810X and DA-310ST that are specially designed for films, pipes, tubes. Added in the formulation, Daikin's polymer processing aids improve productivity and the surface quality of PE films, pipes or tubes.