glass-fibre ribbon

glass-fibre ribbon

US licensee for Faircrete COMPOSITES Glass-reinforced propylopylene compound A new polypropylene compound reinforced with 25% glass fibre has been an...

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US licensee for Faircrete

COMPOSITES Glass-reinforced propylopylene compound A new polypropylene compound reinforced with 25% glass fibre has been announced by ICI Plastics Division. ICI call their product Propathene PXC 5563 and claim that it will provide the mechanical and physical properties associated with thermoplastics like nylon, polycarbonate, acetals and modified polyphenylene oxide, but at much lower cost. A patented chemical bonding system has been developed to provide a strong bond between the glass fibres and the polypropylene. T h e density, tensile stress, flexural modulus and Izod impact strength are given in the table. T h e tensile strength of PXC 5563 at 135°C is the same as that of unfilled polypropylene at 20°C, and the heat distortion temperature at a level of stress of 1"82 MN/m" is 152°C, which is close to the melting point of polypropylene. T h e increase in the rigidity and tensile strength of mouldings is accompanied by major reductions in linear thermal expansion and mould shrinkage (see table), Properties of Propathene PXC 5563

coupled glass-reinforced polypropylene compound Property Density* Tensile stress at break* Flexural modulus* Izod impact strength* Mould shrinkaget Coefficient of linear thermal expansion at 200C

Typical value 1.08 g/cm 3 90 M N / m ' 4.35 GN/m' 1.55 J 0.2-0.8% 3X10-~/°C

*At 230C. fThe material is anisotropic and~the values depend on the orientation of the glass fibres in the moulding. but the surface gloss of the mouldings is lower than that of unfilled grades of polypropylene. T h e material will lend itself best to components which, are subjected to high stress and must also withstand high temperatures, either continuously or for long periods intermittently. ICI envisage applications in the following fields: vehicles (eg housings for water

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pumps), domestic appliances (eg pump impellers), electrical and electronic components (eg housings for motor switch gear) and chemical plant (eg pipe flanges). Injection moulding conditions for PXC 5563 are similar to those used for unfilled polypropylene but dispersion of the glass fibres must also be achieved by suitable adjustment of the back pressure on the screw. High injection rates give the best surface finish but cause a greater breakdown of glass fibre. Shrinkage of Propathene PXC 5563 after moulding is significantly lower than that of unfilled polypropylene. However, like all anisotropic materials, the shrinkage in line of flow is greater than the transverse shrinkage. ICI Plastics Division, Polyolefines Group, Welwyn Garden City, Hertfordshire, UK

Carbon-fibre/glass-fibre ribbon A new form of carbon fibre reinforcement has been produced by Courtaulds Ltd, specifically for stiffening GRv structures. One or more tows of Grafil HM-S continuous filament carbon fibre are incorporated in a knitted glass fibre tape, approximately 16 mm wide. T h e carbon fibres, which have a diameter of between 2 and 5ram, lie in the centre of the glass fibre ribbon and the whole is impregnated with a resin (2-10% w/w) compatible with the resin system to be used in the composite. T h e ribbon is supplied in continuous lengths wound on a 3 in (76 mm) diameter spool and packed in cardboard cartons. Ribbon with two tows of carbon fibre will cost 10p per metre and with three tows 15p per metre. Significant price reductions are being offered to customers placing large orders. Courtaulds claim that the ribbon can be handled more easily and quickly than ordinary carbon fibre tows, without 'fly' or 'pick-up' problems, and that fibre damage is much reduced. Possible applications include: power boat bodies, sailing dinghies, racing car bodies, water skis, structures for the building industry, hovercraft bodies, furniture and caravans. Courtaulds Ltd, Carbon Fibre Unit, PO Box 16, Coventry CV6 5AE, UK

Laing Construction Services Inc, member company of the Laing Group in the USA, has signed an agreement for the manufacture in North America of Faircrete, a decorative concrete developed by Laing in the U K. The agreement is with Span-Deck Inc, of Nashville, Tennessee. Span-Deck will license precast concrete producers throughout the United States and Canada and will manufacture the necessary machinery for Faircrete production. Span-Deck is a concrete machinery manufacturer and licensor of a proprietary structural floor system which they market in North America. Faircrete was evolved by John Laing Research and Development Limited at Boreham Wood, Hertfordshire, UK. It is made from the conventional constituents of concrete, to which are added polypropylene fibres and air entraining agents. It has the unique ability to hold a deep profiled pattern, while retaining a high degree of workability. Sculptural effects in fine detail can be achieved. Laing Construction Services Inc was set up m the USA to promote the full range of Laing services and experience. Laing Group, 14 Regent Street, London SW1, UK

NRDC manufacturing licences T h e National Research Development Corporation of the United Kingdom recently published a list of inventions which can be licensed by interested companies. Four are directly concerned widl composite materials. (NRDC reference numbers are given in brackets.) Geodetic structure (52192/69) - - a technique for the fabrication of carbon fibre into structural members. Pultrusion (22043/69 cog 22083/69 cog 55188/69) - - a manufacturing procedure for the fabrication of carbon-fibre reinforced members with circular or other sections,

High work of fracture composites ( 4 4 1 8 1 / 6 9 ) - - c o n c e p t of a duplex fibre which increases work of fracture in composites (see Composites, Volume 2, page 80). Potential applications are invited.

Fibre-thermoplastic moulding compositiol:s (49365/69) - - process for preparing low density moulding compositions from short fibres and resins (eg asbestos and polypropylene). Further details about these inventions can be obtained by writing to the Information Officer, NRDC, Kingsgate House, 66-74 Victoria Street, London SW1E 6SL, UK

COMPOSITES January~February 1972

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