Abstracts of patents

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

UK PATENTS

Composite structure reinforcement (Foster-Miller Inc., USA) GE 2 2f I 142 A (22 June 1989) A novel technique for translaminar reinforce- ment of a composite structure is described. Perpendicularly arranged boron filaments are supported in a polymeric foam (e.g., Polyvinylchloride) which decomposes at the temperature at which the matrix (e.g., epoxy) resin is of minimum viscosity. During the consolidation and curing of the prepreg lay-up, bagged up in an autoclave, the boron filaments (for example) are forced through the release film into plies, without damaging the laminae.

Moulding a recess at an unreinforced location of a CRP panel incorporating reinforcing sheets (BTR Plc, UK) GB 2 21 I 780 A (12 July 1989) In order to locate anchorage points in a GRP freight vehicle body, pressure is applied to a recess-moulding panel is placed over unre- inforced areas and before full cure is reached. Thus a metal rail for anchorage is exposed within the reinforced laminated panel.

Curing a composite skin-stiffeners assembly (Canadair Inc., Canada) GE 2 213 761 A (23 August 1989) Integral stiffeners are incorporated into a laminated panel by laying the prepreg onto a corrugated surface. The valleys are filled with an expandable member and subsequently a prepreg skin layed across the corrugations. After curing the expandable member is removed.

Moulding (HP Chemie Pelzer Research and Development Ltd., Ireland) GB 2 216 062 A (4 October 1989) A technique for moulding automotive body panels from fibre reinforced plastics (eg. phenolic or polyurethane) is described. Compressed air is used to consolidate the plastic, through an overlying polymer mem- brane film. A non-woven fibrous layer or foam is incorporated between them in order to achieve sound absorption. The whole is enclosed in an appropriate mould.

US PATENTS

Continuous monitoring system for compaction behaviour of composite laminates in autoclave curing Jeon, E., Lee, W., Yoon, K. and Kim, T. (Korea Institute of Machinery and Metals, Kyongsangnamdo, Korea) LrS Pat 4831881 (‘3 May 1989) A measuring system for the continuous monitoring of compaction of composite laminates during autoclave curing is described. The system utilizes a thickness measuring sensor and strain amplifying device while the composite is held between steel plates.

Method of making an epoxy bonded rare earth- iron magnet Kass, A. (Eastman Kodak Co., Rochester NY, USA) US Pat 4 832 891 (23 May 1989) A bonded permanent magnet is fabricated by adding particles of the rare earth/iron/boron alloy to the uncured resin epoxy in a solvent, mixing at 120°F so that the metal is coated in resin, cold pressing and curing the epoxy at 250-350°F for l-2 hours.

Reinforced composite product Melee, D. and Lefere, G. (France) CS Pat 4 833 028 (23 May 1989) The product is a layered structure which is formed by rolling at least one lap onto itself in a helical winding or by concentrically forming tubular laps of fabric around an axis.

Method for producing composite ceramic structures Newkirk, M.S., White, D.R. and Dwivedi, R. K. (Lanxide Technology Co., Newark, Del USA) US Pat 4 833 110 (23 May 1989) A two stage method for producing a self- supporting ceramic body. In the first stage a parent metal is heated in the presence of vapour-phase oxidant to form a body of molten parent metal. Molten metal is drawn through the oxidation reaction product to give a polycrystalline material of the oxidation product. The second stage involves comminu- ting the polycrystals to a particulate size to use as a filler and forming a permeable mass of the filler. Molten parent metal formed as in the first stage is infiltrated and oxidized to give a composite.

Method for making an end connection for composite shafts Salzman, R.N., Blakley, R.A., Schutte, M.D. and McDermott. K.T. (General Signal Corpn., Stamford, CN, USA) US Par 4 834 932 (30 May 1989) Intersecting transverse and circumferential grooves are formed in the exterior surface of a composite filament libre reinforced solidified resin tube. Equivalent grooves are formed on the inside of a composite connector tube which is screwed onto the first tube. Resin is injected via keyways into the join and solidified.

Method of moulding fibre-reinforced articles Gardner. H.C. and Domeier, L.A. (Union Carbide Corpn.. Danbury CN. USA) US Par 4 834 933 (30 May 1989) Thermosetting organic material is injected into a bonded web of fibres in a heated metal die. The die temperature is high enough to cause curing. The thermosetting material contains one component with two or more polymeriza- ble carbon-carbon bonds, an ethylenically unsaturated monomer, and an initiator.

Method for making composite articles that include complex internal geometry Pyzik, A.J., Ott, J.J. and Jankowski, S.J. (Dow Chemical Co. Midland, MI, USA) LrS Par 4 834 938 (30 May 1989) An insert body with an external surface corresponding to the internal surface required is made of a material with a wetting temperature less than that of the product. A porous compact of the product material is formed about the insert which is heated so that the insert melts and infiltrates the porous compact giving the finished composite article.

Method for the production of whisker-reinforced refractory composites Freitag, D.W. (LTV Aerospace and Defense Co., Dallas, Texas, USA) LIS Pat 4 840 763 (20 June 1989) A suspension of colloidal refractory powder, colloidal sintering aid and refractory rein- forcing whiskers is made and conformed to a desired configuration and into contact with a semi permeable membrane. Pressure is applied to the suspension to expel liquid through the membrane and give a green body of 40% density. The body is dried and liquid phase sintered under nonoxidising conditions.

56 Composites Manufacturing March 1990