Latest thermoplastic elastomers offer benefits as modifiers

Latest thermoplastic elastomers offer benefits as modifiers

Additives for Polymers August 1998 The company has recently introduced a new clear impact modifier in its Blendex range, for use in all clear calend...

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Additives for Polymers

August 1998

The company has recently introduced a new clear impact modifier in its Blendex range, for use in all clear calendered PVC applications including furniture film, credit cards, advertising boxes, blister packs and applications such as bottles. Coded Blendex 415, it is claimed to offer an ideal balance between clarity and gloss with very low stress whitening, excellent thermoforming ability, easy processing and low haze. In combination with the 590 grade, it produces a formulation which virtually eliminates sticking problems. During the past year, the company broadened its product portfolio with the introduction of Ultranox 668, a general purpose complementing the highphosphite performance Ultranox 626 and 641 grades, the latter of which is now in full commercial production at GE’s new plant in West Virginia, USA. In practice, it has been found to give better processing both with polypropylene and polyethylene, including reduced screen plugging (a problem in fibre production, when molten polymer goes through fine screen packs in the extruder and leaves some impurities behind). It has also been found virtually to eliminate the problem of film build-up on the die-lip of the extruder. New phenolic antioxidants Ultranox 276 and 2 10 have also been added, improving the processing stability and long-term heat ageing performance of polymers. Contact: GE Specialty Chemicals Inc, PO Box 1868, 501 Avery Street, Parkersburg, WV 26102-1868. USA; tel: +I-304 424 5698

Latest thermoplastic elastomers offer benefits as modifiers Improved performance benefits for the automotive industq are offered by recent developments in thermoplastic elastomers as modifiers for plastics. Some insight was presented at the recent World Congress on Engineering Thermoplastics, held in Zurich, Switzerland, in June. Shell’s Kraton polymers team described recent developments in

01998 Elsevier Science

the Kraton G range which will assist manufacture of plastics components with an overmoulded ‘soft touch’ surface layer. Offering improved touch and grip, as well as better visual appeal, the surface layer modifies the hard base polymers to have the benefits of key properties of thermoplastic elastomers, such as better impact performance especially at low temperatures. Current uses of Kraton G include air bag covers, gear and handbrake handles, cables and coextruded door profiles. There is the potential for many other applications in interior and exterior surfacing, claims Shell. l

Kraton polymers are produced in several types. The D series has an unsaturated rubber midblock - styrene-butadiene-styrene (SBS), and styrene-isoprene-styrene (SIS) - and the G series has a saturated midblock - styrene ethylene/butylene styrene (SEBS) and styrene ethylene/propy- lene (SEP). The G series has increased resistance to oxidation and weathering, higher service temperature and better processing stability.

Contact: Shell International Chemical Co Ltd, Shell Centre, London SE1 7PG, UK; tel: +44-l 71 934 1234; fax: +44-I 71 934 5252

Innovative tin stabilizers are free of sulphur Two innovative sulphur-free tin stabilizers for PVC have been introduced by Elf Atothem: Thermolite 410 (for white and coloured rigid applications, such as window profiles) and Thermolite 450 (specifically developed for translucent applications, such as roofing). The additives, available in solid tablet form, and easy to handle, ensure that rigidity is maintained in the PVC compound. Being free of sulphur, there is no unpleasant odour during handling and extrusion. They have good self-lubricating properties and give end-products a high level of weatherability, offering a technical and cost-

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