Polyolefin Additives 2009: a success for polyolefin compounding industry amid gloomy economy

The recent AMI conference, Polyolefin Additives 2009, in Cologne was very successful given the current economic climate, with representatives from across the compounding industry and the supply chain. Noru Tsalic of AMI Consulting reviewed the European market, outlining the 3% annual growth in polyolefins from 2005 to 2007, falling in 2008 but expected to grow slowly to 2012. Overall consumption in 2008 was 8.7 Mt of L/LDPE, 5.6 Mt of HDPE and 9.5 Mt of polypropylene (PP). The global agricultural film market was 3.55 Mt in 2007 with European demand at 0.71 Mt; 40% is used in greenhouses according to Enrique Espi of Repsol. Additives include photostabilisers, UV absorbers, NIR absorbers/reflectors, mineral fillers and surfactants. The European standard, EN 13206, covers some but not all of the property requirements. The three major problems are: the synergies and antagonisms in formulations, the lack of standard test procedures and matching field results to film properties. Croda Polymer Additives has launched new metal oxide additives, which are UV absorbers thus protecting both the polymer and, for example, packaging contents. When UV is absorbed the electrons move to an excited state and then relax releasing thermal energy. The issue for inorganic materials has been transparency: the new zinc oxide and titanium dioxide products are ultrafine. In tests the new products were still as effective after 1000 hours of exposure, whereas organic absorbers (benzophenone and benzotriazole) reduced significantly. Albemarle has studied stabilisation of PE for pipes and has developed two additives: Ethanox 330 (1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene) and Ethanox 310 (tetrakismethylene(3,5-di-t-butyl-4- hydroxyhydrocinnamate) methane). The oxidation induction time (OIT, ASTM D3895) was tested at different depths in the pipe wall: the outer layer is affected by loss of stabiliser. Performance was compared with Irganox 1010 and in combination with different pipe fittings. Ciba has examined stabilisation in a variety of applications including LLDPE sports grass, PP carpet yarn and a HDPE bottle crate. For example, IRGASTAB® FS 533 used in PP yarn provides process stabilisation during spinning, CHIMASSORB® 2020 is a light stabiliser and Filter Pressure Value (FPV) pigments provide the colour. The performance issues for the crate are dimensional control, light and weathering resistance and wash resistance. Phosphites are used as process stabilisers and Dover Chemical is a leading supplier. They are used as secondary stabilisers to prevent degradation due to heat, shear, catalysts, etc. and preserve colour and melt flow during processing. Trisnonylphenyl phosphite has good cost performance and ideal properties, indirect food contact approval and GRAS. There is a new high performance liquid phosphite currently undergoing approval. Silicones, such as those from Wacker Silicones, are used as process aids. Geniosil is a functional silane for crosslinking polyolefins and linking polymer and filler. Genioplast is an additive to improve polymer flow and surface properties. Antistatic agents are used extensively in polyolefins, chemicals include alkyl sulphonate, ethoxylated fatty alkyl amine, glyceryl monostearate and quaternary ammonium salts. GRAFE has new high performance antistat masterbatches combining synergistic organic antistats for non-food transparent and coloured applications: the effect lasts for more than 2 years. Food contact safety is vital for the many polyolefins used in packaging. TNO is one of the major European test houses for approvals. There are European, US (FDA) and national regulations. Framework Regulation (EC) 1935/2004 governs EU food safety - packaging materials should not endanger health, change food composition or alter organoleptic properties. There are positive lists of additives and migration limits. Milliken produces a sorbitol clarifier that is food contact approved. Millad® NX8000 allows polypropylene to approach the clarity and appearance of polystyrene and polycarbonate creating material substitution opportunities, for example in thin wall injection moulding. Atlas Material Testing Technology has looked at accelerated weathering testing to predict service life of materials. One example is pigmented, stabilized, long fibre-reinforced PP in car bumpers, where gloss loss, whitening and reduced mechanical properties occur. It is difficult to develop tests to reproduce what is seen in practice, as factors such as intermittent rain and temperature affect leaching of additives such as HALS. Long fibre reinforced PP is being used extensively in automotive applications. Future Advanced Composites & Technology compounds PP with 40-60% fibre, combined with heat stabiliser, anti-UV in a highly additivised concentrate format, for use in automotive compounds. BYK Chemie has addressed the issues of odour and emissions from polyolefins used in the automotive sector, which can be due to residuals from the polymerisation process, additives and processing aids. Traditional solutions include adding zeolites or charcoal as adsorbers (but these can affect properties), or injection of nitrogen, carbon dioxide or water during extrusion for extraction. The company has developed a stripping agent, which works by producing a surface micro-foam during , wetting the VOC and odour components. This foam collapses during downstream degassing and is removed. ICL Industrial Products supplies brominated flame retardants, which are very effective at preventing fires in many applications, for example in construction products such as PE sheets and in PP stadium seats. Tris (tribromoneopentyl) phosphate (FR-370) and TBBPA bis(2,3 dibromopropylether) (FR-720) give a V2 rating in PP and PE, while DecaBDE gives a V0 rating. There are also polymeric brominated flame retardants which have lower toxicity ratings. The photovoltaic market grew by 60% in 2006 in Germany, the world's leader. PolyOne has developed compounds to meet the demanding performance standards of fire and heat resistance, weatherability, flexibility and maintenance of electrical properties. The company has low smoke and fume, zero halogen (LSF0H) materials for primary and secondary insulation in wire and cable. Laser marking is difficult for PE and PP as they have low heat absorption and little colour change. It is a quick and food contact approved method of labelling, for example in bottle caps. DSM Micabs supplies an additive to facilitate laser marking. Borealis has studied beta-nucleation of polypropylene. It slightly increases glass transition, and improves impact strength. In copolymers, the molecular weight of the ethylene-propylene rubber (EPR) phase has a great effect on the ductile-brittle transition. Nanocomposites are the subject of intensive research. AkzoNobel is looking at layered double hydroxides (synthetic nanoclay) in polyolefins. It can improve impact strength, flame retardancy, barrier properties and rheology. Perkalite is patented and can be processed on conventional equipment. It can be used in polyolefin packaging with a fatty acid modifier. With constant changes in legislation for chemicals and applications, the polyolefin compounding market has to keep up to date to supply customers with the right materials. This combined with price pressures during the economic downturn and de-stocking, has left the industry looking for more cost-effective solutions as well. These are some of the issues that are up for debate at the next conference on Polyolefin Additives, which takes place from 23-25 March 2010 at the Maritim Hotel in Cologne, Germany. (Press Release)