Abstracts of patents

UK and US patents are prepared by Drs F. R. Jones and W. E. Lee, of the University of Shefield, UK

UK PATENTS

Controlling injection mould filling by galvanic cell action (Alan Harper Plastech, UK) GB 2 227 567 A (I Augusr 1990) A galvanic cell with copper and zinc electrodes is created when they become immersed in the electrolyte: the liquid resin for resin injection moulding. In the example the fibres are located in the mould rather than in one component. It is claimed that the onset, rate and completion of mould filling as well as the completion of polymerization or resin cure can be monitored or controlled. The latter can be detected since the cured resin no longer acts as an electrolyte.

Logs (Arthur Andrew Curry of UK) GB 2 227 970 A ( I5 August 1990) A simulated log or other comparable articles such as coals or peat can be manufactured by sucking a fibrous slurry onto the surface of a hollow mould. The second layer without suction can be deformed with a tool before final consolidation under vacuum.

Slate-filled resin products (Rotile Ltd., UK) GB 2 228 889 A (12 September 1990) A formulation comprising 50-70% slate dust, IO-30% limestone, O-IO% glass fibre in polyester resin ( IS-30%) is extruded through a rectangular die and pressed between planar plates, one of which bears an impression of a natural slate product.

Forming a fibre reinforced thermoplastic article (Rover Group Ltd., UK) GB 2 229 392 (26 September 1990) A method of manufacturing an injection moulded article, such as a vehicle door backup beam, comprises placing a preform of relatively long reinforcing fibres in the cavity of the mould and injecting thermoplastic to encapsu- late it. Part of the cavity can be precoated with thermoplastic to provide a good surface finish. A good finish can also be obtained by slight opening of the mould for further injection of thermoplastic.

Moulding a lever (Aisin Seiki Kabushiki Kaisha, Japan) GB 2 229 668 A (3 October 1990) A method of manufacturing a lever for an automotive door check device is described, in which a reinforced plastic is injected into one end of a split mould containing a longitudinal metal insert so that the fibres are aligned longitudinally in the component.

Method of constructing tubular spars (I. C. Howlett ol UK) GB 2 230 225 A (17 October 1990) Tubular spars, for use on sailing vessels, are moulded by laying FRP into a splittable channel section mould to form the periphery. Removal

of the sides of the mould enables several spaced farmers to be mounted, onto which a skin, for example, of plywood, can be fixed. This acts as a support for the remaining layers of FRP. After curing, the farmers may be either removed or left as an integral part of the spar.

US PATENTS

Reinforced polymer sheet Van Breen, A. W. and Gillemans, J. C. M. (Shell Oil Co., Houston, TX, USA) I/S Put 4 861 428 (29 Augusr 1989) The process uses paper-making technology to produce fibre-reinforced polymer sheet. Particles and fibres ( < 2 mm long) of thermoplastic polyketone polymer are mixed with water to form an aqueous dispersion which is passed onto a filter. The water is then drained from the dispersion. The tibres ire used in the amount of 5-45 pbw per 100 pbw of polymer.

Impact resistant composites Browne, J. M. (Pleasant Hill, CA. USA) I/s Pat 4861812 (29 August 1989) The synthetic foam prepreg composite contains at least one layer of a thin film of uniform thickness of a syntactic foam containing rigid microballoons in a resin matrix. This layer is laminated toa prepregconstruction ofcontinu- ous filaments of high modulus fibre in a thermosetting resin matrix. The matrix resin of the syntactic foam is compatible and co-curable with the resin matrix of the prepreg. The layer is close enough to an impact-prone surface to withstand impact through the surface.

Compositions for preparing cement-adhesive reinforcing fibres McAlpin, J. J. and Chow, W. Y. (Exxon Chemical Patents Inc.. Linden, NJ, USA) LrS Pat 4 861 812 (29 August 1989) The cement contains from I-IO volume % fibres. The fibres are made of from 90-99 weight % of an olefinic polymer containing I - 10 weight % of a modifying agent which is the reaction product from dry blending an alkylamino alkoxysilane with an acid-modified polyolefin in an amount of from 50- I50 % of the stoichiometric amount required to react with the acid functionality of the acid-modified polyolelin.

Continuous reinforceme@ method for flexible bearing laminate McGreggor, J. D. (Morton Thiokol Inc., Chicago, IL, USA) US Par 4 863 367 (5 September 1989) A stacking tool is used for preparing a helix of pre-impregnated reinforcement material with a shaft and an attached conical member with a wide and narrow end. The conical member has a continuous helical ridge formed on the conical surface with one side sloped.

Method for the manufacture of a composite fibre, web, strand or woving Schlachter, F. (Manville Corp., Denver, CO, USA) US Pat 4863502 (5 September 1989) Glass fibres are drawn, attenuated onto a rotating drum, removed after one drum rotation and formed into a whirl which is drawn off as a web. The improvement consists of separating filaments of yarn of other fibres and uniformly introducing these separated fibres of other material to the glass tibres prior to forming.

Process for manufacturing composite reinforce- ment elements woven in three dimensions Cahuzac, G. J. and Monget, F. (Aerospatiale Societe Nationale Ind.. France) LIS Pat 4 863 660 (5 September 1989) The method utilizes a disposable loam mandrel. Rigid members are implanted into the mandrel so that some extend from the surface. Successive layers of tibres are stretched out between the rigid members so that they are crossed in at least two directions. The layers of fibres are interconnected by means of fibres extending perpendicularly by driving a needle having an eye carrying the fibres through the layers. The fibres are impregnated with a binder which is hardened and the needles and mandrel are withdrawn.

Continuous process for making coated composite hollow fibre membranes Puri, P. S. (Air Products and Chemicals Inc., Allentown, PA, USA) (is Pot 4 863 761 (5 September 1989) The process applies a generally uniform, semi-permeable coating on a hollow fibre substrate to produce a coated composite hollow fibre membrane. A hollow fibre substrate is passed at fixed tension and speed into a polymeric solution capable of forming a semi-permeable coating. The libre is axially drawn from the solution through a coated circular die such that a polymer solution coating is formed. The coated hollow fibre is dried by passing through a convective Row tunnel with predetermined temperature profile and air flow.

Damage tolerant composites containing infusible particles Gawin, I. (Hercules Inc., Wilmington, DE, USA US Pat 4 863 787 (5 September 1989) The prepreg manufacturing process requires forming a thermosettable epoxv resin composi- tion with infusible, IO-75 pm diameter, rubber polymer particles. The epoxy resin can be cured into a crosslinked phase-separated thermoset with a KI, above about I MPa m’jz. The resin and high strength filament bundles or tows are combined so that more than 50% of the rubber particles with diameter greater than 10 pm are on the surface rather than in the bundles or tows.

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