Abstracts of patents

Abstracts qf UK and US patents are supplied by Dr F.R. Jones, Dr W.E. Lee and Dr R.J. Hand of the University of Shefield, UK

UK PATENTS

Polyimide composition and prepreg and laminate thereof (Matsushita Electric Ltd., Japan) GE 2 230 785 A (31 October 1990) Addition of triallyisocyanurates to polyimide resin reduces the inherent viscosity and surface tension of the solution and improves resin impregnation into the fibres for laminate fabrication.

Preparation of bituminous concrete comprising wire pieces (N.V. Bakaert SA, Belgium) GB 2 231 574 A (21 November 1990) The manufacture of castable hot bituminous concrete in which a multiplicity of steel wires are dispersed, is described. The wires are held together by a binder that disintegrates both the cementitious concrete and by melting into the matrix of this disclosure, which enables the bundles to be used in both matrices.

Manufacture of composite vehicle drive shafts (Dana Corp., USA) GB 2 231 637 A (21 November 1990)

The title component is manufactured by filament winding a reinforcing sleeve onto a mandrel. Some of the fibres are aligned longitudinally and uniformally around the circumference and held in position by overwinding with fibres at angles to them. The preformed sleeve is trans- ferred onto a cylindrical aluminium tube, and secured to it during the consolidation process.

Manufacture of composite vehicle drive shafts (Dana Corp., USA) GB 2 231 638 A (21 November 1990) Individually fibre reinforced tubular elements for the title application are manufactured by dry filament winding with an independent resin stream, onto a longitudinally extending series of metal tubes formed internally with plugs. After resin curing, the tubes can be severed at the joints.

Moulding a reinforced article (Rover Group Limited, UK) GE 2 232 373 A (I2 December 1990) In a process similar to reinforced resin injection mbulding the discontinuous fibre resin dis- persion is injected into a mould containing a long fibre reinforcement. In the process, the area of the mould without preform, achieves a higher fibre volume fraction than in the original premix. In this way, the fibre volume fraction in areas (such as ribs) which are difficulty filled with preformed can be success- fully reinforced.

Composites Manufacturing March 1991

US PATENTS

Apparatus and method for impregnating continuous lengths of multifilament and multi- fibre structures Hilakos, W. (General Electric Company, Mt. Vernon, Ind, USA) US Pat 4 864 964 (12 September 1989) Apparatus for impregnating a continuous lengths of multiple fibres or filaments bundles with a molten thermoplastic resin is described. This consists of a chamber containing the molten thermoplastic resin and a shaped pathway through which the fibres or filaments are passed. The resulting composite is sized on exit from the chamber.

Prepress apparatus and method Bishop, R.B., Ash, C.E. and Herliczek, S.H. (Libbey-Owens-Ford Co., Toledo, Ohio, USA) US Pat 4 865 671 (I2 September 1989) Air is removed from between the interfaces of superimposed sheets by enclosing them in an evacuation ring that extends beyond the edges of the sheets and coupling this to a vacuum generator. After evacuation the assembly is pressed between rollers.

Moulding member and method of producing same Tamura, T. (Hashimoto Forming Industry Co., Ltd., Yokohama, Japan) US Pat 4 865 676 (I2 September 1989) A method of producing a composite moulding consiting of a synthetic resin about a core element to be used as a body component in a car or similar is described.

Method for the impregnation of filament would structures with thermoplastic binders Valiance, M.A., Tomkinson-Walles, G.D. and Johnson, R.N. (General Electric Company, Schenectady, NY, USA) US Pat 4 865 788 (I2 September 1989) A method for producing a fibre web using natural and synthetic fibres by mixing the fibres and coating them with a resinous powder is given. The fibres are re-mixed after coating and formed into a mat which is needled and cut.

Method of using composite reinforced grommet Moyer, J.D. (Downingtown, PA 19335, USA) US Pat 4 865 792 (I2 September 1989) A method of reinforcing a substrate containing a polymeric material with an aperture using a grommet consisting of braided filaments impregnated with a polymeric material is described. At least one end of the grommet is expanded radially to from a flange after insertion

into the aperture. Bonding is then achieved between the substrate and the grommet by curing them under pressure.

Process for preparation of composite materials containing nonmetallic particles in a metallic matrix Skibo, M.D. and Schuster, D.M. (Dural Aluminium Composites Corp., San Diego, CA, USA) US Pat 4 865 806 (I2 September 1989) A method for producing a composite consisting of a metallic alloy and a carbon containing nonmetallic refractory material in which particles of the refractory material are oxidized; added to the molten alloy and shear mixed. The resultant mixture is cast.

Method for in-place fabrication of graphite epoxy bushings in graphite epoxy structures Bannink, E.T. (Boeing Corp., Seattle, WA, USA) US Pat 4 867 822 (19 September 1989) The method enables fabrication of a graphite/ epoxy bushing having a desired hole diameter within an existing hole formed in a graphite/ epoxy structure. A cylindrical mandrel with a positive coefficient of thermal expansion which is smaller than the desired hole is provided. A strip of epoxy-impregnated graphite mat is wrapped around the mandrel to provide an assembly having a diameter approximately equal to the diameter of the existing hole. The assembly is inserted into the hole and the mandrel heated to expand it and cure the mat. Upon cooling the mandrel contracts away from the mat and is withdrawn leaving the mat forming a bushing that is bonded to the graphite/epoxy structure. A hole is machined in the bushing having the desired diameter.

Composite bearings having improved wear life Jacobson, C. (Garlock Bearings, Inc., Thorofare, NJ, USA) US Pat 4 867 889 (19 September 1989) A self-lubricating wear resistant composite bearing is made from a supporting shell with a polytetrafluoroethylene fibre lined surface would with a second fibrous material. These fibres are in a polymer matrix of 5-25 weight % powdered carbon and bond to the polymer matrix.

Method of manufacturing a molten metal- resistant ceramic fibre composition Waisala, S. J. and Sane, A.Y. (Stemcor Corp., Cleveland, OH, USA) US Pat 4 868 142 (I9 September 1989)

A frit of CaO, Al,O, and B,O, is mixed with a low temperature organic binder and blended with water and aluminosilicate ceramic fibres with a mean diameter of 1.2 microns. The mix

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