August 1992 Additives for Polymers

PROCESSING

Thermoforming fibre- reinforced composites

GE Plastics’ Polymer Processing Development Center in Pittsfield, Mass., is experimenting with thermoplastic sheet containing over 30% discontinuous glass fibres for an automotive application and is developing new thermofo~able materials with even higher glass contents. Thermoforming Technologies Inc., Seabrook, N.H. is also developing a single- station pressure former with profile heating capability to form reinforced thermoplastic sheet with up to 70% continuous fibre for automotive and aircraft applications.

Paper mill waste for fining plastics

Paper mills in the UK produce over half a million tonnes of pulp residue each year, comprising kaolin and cellulose by- products.

Fosse, of Whetstone Magna, Leicester, (UK) has developed (and patented) technology for converting the pulp into reinforcing fillers for plastics and rubber, which it calls F-Stend.

According to Fosse, F-Stend can be used at higher levels than conventional fillers, while retaining commercially acceptable mechanical properties. Mouldings have good dimensional stability and low shrinkage, it says, and the flow properties highly filled F-Stend compounds are claimed to be superior those containing traditional fillers.

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Fosse is now producing small-scale quantities of the filler, and LDPE and PP copolymer compounds containing it under the name AuRIOL. F-Stend itself is grey, and is available in micronis~ and g~nular versions, for which the company quotes a density of 1.5. The addition rate varies with the properties desired, but property values quoted show that at 30 per cent it provides significant increases in flexural modulus and flexural strength in both LD and PP, with minor decreases in tensile strength. The company says that concentrations up to around 15 per cent can be dry blended, while normal ~om~unding techniques can be used for addition levels from 20 - 60 per cent, and it will advise on this. The AuRIOL LD and PP compounds so far available are aimed at injection and blow moulding, and profile extrusion, and processing advice is available. The LD compound, AuRIOL 103010, is of MFI 0.83 and density 1.080, and the PP compound, coded 203010, is of MFI 1.41, and density 1.060.

Brit. Ph. & Rubb., 1992, (June) 56

e1992 Elsevier Science PubIishers Ltd. 11