Abstracts of patents UK and US patents are prepared by Ors F.R. Jones and R.J. Hand of the University of Sheffield, UK
UK PATENTS Impact resistant fibrous laminate (ICI Americas Inc, USA) GB2242 160A (25 September 1991) An isocyanate-terminated prepolymer and organic carbonate such as propylene carbonate are impregnated into a wide variety of cellulosic materials (such as paper) to give a laminatable 'prepreg'. It may contain glass fibres. The carbonate acts as a reactable viscosity modifier for the impregnation by in situ decomposition into a glycol which can react with the isocyanate prepolymer. These paper-based laminates have superior mechanical properties and have applications such as tables, chairs and tubes. Fibre reinforced elastomeric sheet (T and N Technology Ltd, UK) GB 2 242 859 A (16 October 1991) The title material, which is useful for gaskets, is a laminate of non-woven fibrous fabric---e.g., glass or aramid tissue--impregnated with a suspension of inorganic filler such as calcium carbonate in a curable elastomer, using solution techniques. Lamination as opposed to the conventional 'calendering' produces a less anisotropic material. Siliconised silicon carbide article (T and N Technology Ltd, UK) GB 2 243 601 A (6 November 1991) The title artefact is made by injection moulding a mixture of SiC particles and organic binder, and removing the latter by heat to yield a porous SiC article which can be impregnated with molten silicon to convert the residual carbon to SiC. The latter acts as a binder. The technique has been improved by ensuring that the sprue from the original moulding is hollow and can act as a conduit for the molten silicon. The sprue has excellent properties and can be left intact. A typical example is a sealing ring. Friction material for railway disc pads (Ferodo Ltd, UK) GB 2 244 061 A (20 November 1991) The title materials comprise a reinforcing fibre, a polymeric binder and particulate material. The binder is a heat-resistant EPDM rubber which may optionally contain a resin. Thermoplastic composite material (Rogers Corp, USA) GB 2 244 274 A (27 November 1991) A highly filled thermoplastic extrudate, for use as a printed circuit board material, comprises a rubber-coated ceramic filler in a fluoro or chlorofluoro-carbon polymer. The filler is a fused silica surface treated with a silicone rubber, although glass spheres or microcrystalline silica are also described. Oxides which reduce filler-induced degradation can also be included.
COMPOSITES. MAY 1992
Coated filler particles and method for making same (Rogers Corp, USA) GB 2 244 489 A (4 December 1991) Fillers for composites which are based on silicone-rubber-coated minerals are described. The latter can be a range of particulates, microspheres or fibres. They are prepared by reacting a monofunctionalterminated polysiloxane with a multifunctional silane and silane cross-linking agent to form a reactive silicone network. They are useful as fillers for a range of thermosets and thermoplastics.
US PATENTS COMPONENTS Ceramic composite valve for internal combustion engines and the like Berneburg, P.L. and Rice, R.W. (W.R. Grace & Co-Conn, New York, NY, USA) US Pat 4 928 645 (29 May 1990) A finished ceramic composite valve or preform valve is described, the stem of which comprises a fibrous ceramic sleeving packed with an axially aligned unidirectional cluster of ceramic reinforcing fibres. This is attached to a ceramic bell which contains discontinuous ceramic fibres and is shaped to mate with the valve seat of the engine. Conveyor belt of PVC provided with a compound layer of reinforcing material and a process of weaving said reinforcing layer van Calker, F.R. (Akzo NV, Arnhem, The Netherlands) US Pat 4 928 812 (29 May 1990) A polyvinyl chloride conveyor belt contains a reinforcing compound woven fabric. The fabric has two outer layers of cotten yarns adhered to the PVC matrix and these layers are interconnected to the middle layer by binder warp yarns or filaments. The middle layer has aramid primary warp cables or cords which extend in the direction of the belt. The spaces between these warp cables are 0.5-2 times as wide as the outer diameter of the cables and are filled rectilinearly with nonaramid cotton filling warp members. Titanium diboride ceramic fibre composites for Hall--Heroult cells Besmann, T.M. and Lowden, R.A. (Martin Marietta Energy Systems Inc, Oak Ridge, TN, USA) US Pat 4 929 328 (29 May 1990) A preform fibre matrix is infiltrated with titanium diboride by holding the matrix at about 900°C whilst passing hydrogen, boron trichioride and titanium tetrachloride through the matrix. The fibres may be silicon carbide, carbon, alumina, mullite, aluminium nitride, boron nitride or mixtures thereof and the matrix has a means to mount the finished cathode in a HalI-Heroult cell for aluminium smelting.
Hollow shell fibre reinforced resin impregnated bicycle wheel construction and method therefore Lewis, R.H. (Hamilton-Sattui, Napa, CA, USA) US Pat 4 930 843 (5 June 1990) A bicycle wheel with not more than five spokes is described wherein both the spokes and the central hub have a hollow fibrereinforced resin construction. The rim consists of fibre-reinforced resin. Structure with a multiply fabric reinforcement and a method for producing same B6ttger, W. and Bicdermann, K. (Vorwerk & Co Interholding GmbH, FRG) US Pat 4 931 345 (5 June 1990) A multi-ply fabric comprises a yarn of aramid fibre, carbon fibre, ceramic fibre or fibreglass with filling weft threads of polyamide or polypropylene extending between the plies. The whole is impregnated with a resin and then cured. Pultruded composite sign and process therefore Perko, J.E., Wirth, G.J. and Foxgrovcr, B.A. (W.H. Brady Co, Milwaukee, Wl, USA) US Pat 4 935 279 (19 June 1990) A composite sign consists of a longitudinally continuous sheet of printed matter attached to a fibrous component. The whole of this sheet is pulled through a resinous component and a forming die so that the sheet is encapsulated by the resin and the information is visible. Transmission belt with anisotropic composite material having an elastomer matrix Colley, R., Lecouturicr, F. and Ledcvehat, C. (Caoutchouc Manufacture et Plastiques, Versailles, France) US Pat 4 936 814 (26 June
1990) A transmission belt comprises at least one layer. Each layer contains a fibre reinforcement means including fibres with a maximum length of about 30 mm generally uniaxially orientated in an elastomeric matrix containing at least one thermosetting resin. The direction of reinforcement of at least one layer is perpendicular to the longitudinal axis of the belt. Composite sign post Zion, E.M. and Freeman, J,E. (John E. Freeman, Big Spring, TX, USA) US Pat 4 939 037 (3 July 1990) A thin-walled tubular sign post with a slot-in ground anchor and locking means comprises at least one segment, each segment being constructed of a glass fibre-reinforced resin. The glass fibre content is between 55 and 75 weight % and the fibres arc orientated transversely to the longitudinal axis of the post.
MATERIAL S Preform wire for a carbon fibre reinforced aluminium composite material and a method for manufacturing the same
Kyono, T., Ohnishi, S., Hanano, T. and Hotta, T. (Agency of Industrial Science and Technology, Tokyo, Japan) US Pat 4 929 513 (29 May 1990) A continuous fibre bundle of carbon filaments, each covered with one or two materials selected from carbon, silicon carbide, titanium, titanium carbide, boron and titanium boride, is infiltrated with a matrix of aluminium or aluminium alloy each of which contains not more than 0.1% copper and 0.45% silicon. Fibre-reinforced thermoplastic panels Wahl, L. and Vogel, H. (BASF Aktiengesellschaft, Ludwigshafen, FRG) US Pat 4 931358 (5 June 1990) Fibre-reinforced, thermoformable, semifinished material contains a thermoplastic polymer, a needled textile fabric of at least two A layers of continuous filament yarn orientated in at least one preferred direction and at least one B layer of unorientated fibres. The A layer has an areal mass of not more than 0.3 kg m ' and the mass ratio of the A:B layer is between 80:20 and 40:60. Damage tolerant fibre-reinforced composites based on cyanate ester/urea thermosetting composition Quershi, S.P., Gardner, H.C. and NewmanEvans, R.H. (Amoco Corporation, Chicago, IL, USA) US Pat 4 931 496 (5 June 1990) A fibre-reinforced composition comprises a thermosetting composition and a reinforcing fibre. The thermosetting composition contains 100 parts by weight of a cyanate ester and 0.5-12 parts by weight of at least one urea compound with the formula RR INCON R2R 3 wherein R and R 2 are independently selected from hydrogen and organo radicals and R ~ and R 3 are independently selected from the organo radicals. Composite laminate of metal sheets and continuous filaments-reinforced synthetic layers Gunnink, J.W. (Akzo NV, Arnhem, The Netherlands) US Pat 4 935 291 (19 June 1990) A constant thickness covering laminate comprises at least two metal sheets between which there is synthetic layer containing continuous filaments, a large number of which are disposed in parallel lines in one direction at least. A base sheet of metal of variable thickness is covered and bonded on at least one side to the covering laminate. Coated glass fibre composites Rerup, H.J., Drake, E.N. and Duvdevani, I. (Exxon Research and Engineering Company, FIorham Park, N J, USA) US Pat 4 935 301 (19 June 1990) A composite comprises 0.1-60 weight % bundles of glass fibres encapsulated in a 0.l-100 p.m thick polymeric coating which does not impregnate the bundles. The coating is an interionic complex of neutralized sulphonated polymer and an amine-containing polymer. Fibre-reinforced composite comprising mica matrix or interlayer Beall, G.H., Chyung, K., Dawes, S.B., Gadkaree, K.P. and Hoda, S.N. (Coming Incorporated, Coming, NY, USA) US Pat 4 935 387 (19June 1990) A ceramic-matrix composite comprises a crystalline ceramic, glass-ceramic or glass matrix and amorphous or crystalline inor-
ganic fibres. A layer of sheet silicate crystals is present on or in close proximity to the fibres so that there is a sheet silicate interface between the fibres and the matrix. Prereaeted inhibitor powder for carboncarbon composites Gray, P.E. (Rohr Industries, Inc, Chula Vista, CA, USA) US Pat 4 937 101 (26 June 1990) Boron or a boron-containing compound is reacted with a metal, metalloid or compound of these to produce particles about 10 ~tm in diameter. These are homogeneously dispersed in a carbon char-yielding material and the whole is carbonized by heating to produce an oxygen-resistant carbonaceous structure. Core member for fabrication of shaped plastic Takashima, K. and Moriwaki, K. (Toyo Cloth Co Ltd, Sennan and U-PICA Co Ltd, Tokyo, both of Japan) US Pat 4 939 020 (3 July 1990) A porous core member has voids capable of being impregnated with a liquid resin between matrix portions that are made of non-woven fibres coated with a thiocyanatecontaining vinyl resin with microvoids in it, Composite materials having improved fracture toughness Petit, J.I., Bretz, P.E., Paris, H.G., Sawtell, R.R. and Denzer, D.K. (Aluminium Company of America, Pittsburgh, PA, USA) US Pat 4 939 032 (3 July 1990) The composite consists of a high strength aluminium alloy matrix, comprising essentially aluminium, iron and cerium, and inclusions which have a greater ductility than the matrix. The bonding between the inclusions and the matrix is such that a propagating crack is forced to pass through at least one inclusion. Light metallic composite material and method for producing thereof Inabata, T. (Inabata Techno Loop Corporation, Tokyo, Japan) US Pat 4 939 038 (3 July 1990) Matrix powders selected from aluminium, magnesium, zinc, copper, brass, bronze and light aluminium alloys are mixed with 10-70 volume % additives. The additives consist of at least one fine granular material selected from borosilicate, silica, silica-alumina and silica-alumina-calcium glasses; sintered metals; and silica, alumina and zirconia. Each of the additives has a lower density than the matrix powder and a particle diameter of less than 300 ~tm. The mixture is formed into a desired shape and heated to a temperature such that 30-70% of the matrix powders are softened, thus compositing the whole without melting any of the other components. Transformation toughened ceramic alloys Ketcham, T.D. (Corning Incorporated, Coming, NY, USA) US Pat 4 939 107 (3 July 1990) A transformation toughened ceramic consists of 79-99.5 mole % of ZrO 2, HfO2, ZrO 2HfO 2 solid solution or their partially stabilized equivalents and 0.25-15 mole % of at least one stabilizer oxide and 0.25-6 mole % of a toughening agent. The stabilizer may be 0-7 mole % scandia, yttria or a rare earth metal oxide of the form Re20 3 where Re may be La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb or Lu; or 0-15 mole % ceria or
titania. The toughening agent may be 0-6 mole % MgWO4, MgMoO4, CaWO4 or CaMoO4 or 0--4 mole % WO3 or MoO3. In addition a transformation-toughened ceramic resistant to attack by vanadium at elevated temperatures is described, consisting of 65-99.5 mole % hafnia, partially stabilized zirconia or hafnia, or zirconia/hafnia solid solution or its partially stabilized equivalent and 0.5-35 mole % MVO4 where M may be Mg2+ Ca2+, Sc,~+, y3+. Sn4+ Ti4+, La3+ Ce 3+, Ce 4+, pr 3+, Nd 3+ " Sm -~+, Eu 3+, Gd 3. , Tb 3+, Dy 3+, Ho 3+. Er 3+, Tm 3+, Yb 3+ or Lu 3+ " Glass fibre reinforced thermoplastic moulding compositions based on polyesters and graft polymers Seiler, E., Ruppmich, K., Knoll, M.. Heckmann, W., Lausberg, D. and Bueschl, R. (BASF Aktiengesellschaft, Ludwigshafen, FRG) US Pat 4 939 201 (3 July 1990) A thermoplastic moulding composition contains 45--90 weight % of a polyester (50-80 weight %) and a graft copolymer (10-25 weight %); 1-20 weight % of a polymeric component with carboxyl, carboxyl derivative, hydroxyl or epoxy groups; and 5-50 weight % glass fibres.
PROCESSES Surface-coated SiC whiskers, processes for preparing the same, ceramic reinforced with the same, and process for preparing said reinforced ceramic Sugihara, K., Yamamoto, M., Kida, T. and Fukazawa, M. (Tokai Carbon Co Ltd, Tokyo, Japan) US Pat 4 929 472 (29 May 1990) A thermosetting resin is dissolved in an organic solvent and SiC whiskers are dispersed in the resulting solution. The whiskers are then separated by filtration, the solvent removed by drying and then the thermosetting coating on the fibres is cured by heating. The fibres are then fired in a non-oxidizing atmosphere at temperatures between 800 and 1600°C to carbonize the thermosetting layer and thus produce thin carbonaceous layers on the surfaces of the SiC whiskers. Carbon--carbon composite structural assemblies and methods of making the same Washburn, R.M. and Dodson, J.D. (Acurex Corporation, Mt View, CA, USA) US Pat 4 929505 (29 May 1990) Carbon/carbon composite structures with at least one resilient surface are fitted together by compression such that they remain engaged when the external forces are removed, Before fitting a layer of charforming material is coated over at least one of the engaging surfaces. The whole is then heated after fitting to form a layer of charred material which connects the two assemblies. Method of obtaining a filament-containing composite with a boron nitride coated matrix Singh, R.N. and Gaddipafi, A.R. (General Electric Company, Schenectady, NY, USA) US Pat 4 931 311 (5 June 1990) Matrix-forming ceramic material is admixed with an organic binder and formed into a tape. Boron nitride is deposited on filaments with a diameter of at least 50 ~tm and a length of at least l0 times the diameter. These
COMPOSITES. MAY 1992