New developments in rotational molding

Tag : spray foam catalysts

New developments in materials, processes and machinery wereintroduced at an annual meeting of Association of RotationalMolders (ARM).
Nova Chemicals introduced an octane based HDPE copolymer with abalance of processability & stiffness, with 3.5 MFR and 0.941density. In applications such as chemical and water tanks, cycletime is reduced by 10-15% as compared with a comparable 2 MFRgrade. It can fill complex parts as well as a 5 MFR hexenecopolymer. Very low catalyst residues are said to provide superiorwhiteness and easy demolding. Other applications include marineequipment and waste containers.
ICO Polymers has introduced the first crosslinkable semi-conductivePE compounds for rotomolding. It provides high flame resistance andtoughness for demanding static-sensitive applications.Non-crosslinkable semi-conductive LLDPE that is stiffer thanprevious grades is another new compound developed by ICO Polymers.
A new nucleating agent from Milliken Chemicals is used in MDPErotomolding grades. Already commercialized in packaging film,Hyperform HPN20E is said to provide faster cooling without warpage.The additive helps PE crystallize faster, reducing cooling time.The first commercial use is a rotomolded water tank in LatinAmerica, which boasts a 30-40% productivity improvement.
New labeling approaches are emerging to help rotomolders meetgrowing customer demand for product traceability, name-brandrecognition and decorative quality. The latest from New Zealand 'sPolymer Systems International Ltd., is a new in-mold labeling (IML)system which eliminates many of the limitations associated withapplying graphics to already molded parts. The olefin-based opaquelabel is compatible with PE and is placed manually in the mold,which can be at virtually any temperature. This enables molders tokeep cycle times to a minimum by not requiring longer cooling timesto bring molds within a low temperature range. No spray adhesive isrequired because the label carries its own. For applications whereIML is not practical, the label can be rolled onto a reheated partin a post-mold operation.
Winners of the ARM parts competition included the Cosmo container,claimed to be the industry's first plastic collapsible containerfor the portable storage and moving market. The 700-lb, 8x5x8 ft PEcontainer, developed by Nova Chemicals, collapses to less thanone-third of its height when empty. The prototype design, slatedfor commercial production early this year, replaces wood and metalstorage boxes.
Another innovative application was the industry's first rotomoldedfence from SimTek Fence, Utah . The simulated rock privacy fence isdesigned to fill a gap between extruded PVC and real stone. Itconsists of foam-filled posts and rotomolded hollow panels that aresteel-reinforced at the top and bottom. The 6x6 ft panels include120 hidden kiss-offs for structural integrity. Tongue-and-grooveassembly accommodates thermal expansion.