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Sawblade segments utilising polycrystalline diamond grit
positioned so that part of the concrete is retained within the apertures by the web member during the setting of the concrete. Sawblade segments utilising polycrystailine diamond grit Deakins, M.E., Slutz, D.E., Johnson, N.R., Clark, T.J. and Bovenkerk, H.P. (General Electric Company, Worthington, OH, USA) US Pat 4 883 500 (28 November 1989) A sawblade cutting segment has both thermally stable polycrystalline and single crystal diamond cutting elements dispersed in a bonding matrix. Composite and article using short length fibres at oblique angles Harpeil, G.A., Li, H.L., Kwon, Y.D. and Prevorsek, D.C. (Allied-Signal lnc, Morris Township, Morris County, N J, USA) US Pat 4883 700 (28 November 1989) Two multilayer composites are formed from a plurality of prepreg layers. In cases one and two each layer consists of either at least two coplanar fibrous elements or one fibrous element respectively. In both cases the elements consist of unidirectional fibres embedded in a polymeric matrix. The fibres are orientated at an angle of 30° to 60° to the longitudinal axis of the element and are up to 0.2 m (sic) in length.
MATERIALS Cementitious composition Viles, R.F. (Fosroc International Limited, Birmingham, UK) US Pat 4 875 937 (24 October 1989) A rapid setting and hardening, dry cementitious composition that forms ettringite on mixing with water consists of 10-50% high alumina cement; at least 11.4% 13-anhydrite; 1-13% by weight relative to the high alumina cement of aluminium sulphate; 3-9% by weight relative the high alumina cement of a source of free lime; and at least 10% of a reactive filler. Ceramic bodies having a plurality of stress zones. Virkar, A.V. (Ceramatec Inc, Salt Lake City, UT, USA) US Pat 4 876 148 (24 October 1989) A green ceramic body contains at least two compositional zones; the first consists of sinterable ceramic particles and the second of particles with the same composition plus a significant content of ceramic fibres or whiskers with a lower thermal expansion coefficient than the sinterable particles of the first layer. On sintering and cooling, tensile and compressive stresses are generated in the first and second layers respectively. Building material and method of producing the building material Eichen, H.R. (Treestone Corporation, Ventura, CA, USA) US Pat 4 876 151 (24 October 1989) A two layer composite building material is claimed in which the first layer consists of a cured mixture of approximately 20 wt% cellulose fibres and 20 wt% sand; the remainder of the mixture being cement. The second layer consists of approximately 5 wt% cellulose fibres and 35 wt% sand; the remainder of the mixture being cement.
Process for the preparation of cyanate resinbased prepregs and films which maintain their tack Thorfinnson, B.S. (BASF Corporation, Parsippany, N J, USA) US Pat 4 876 153 (24 October 1989) A multiple layer composition has a first layer of a cyanate-functional, heat-curable resin and a second layer which is a silicone-coated release film containing an amount of metal catalyst which is effective to cause no greater than a 2.5 fold increase in the resin viscosity after storage at room temperature for one week. Composite wood structures bonded by poly(vinyl acetate) emulsion adhesives containing an alkoxysilane Witucki, G.L. and Plueddemann, E.P. (Dow Corning Corporation, Midland, MI, USA) US Pat 4 876154 (24 October 1989) A composite wood structure is bonded by a water-borne emulsion adhesive based on a poly(vinyl acetate) resin and 0.5-5.0 wt% alkoxysilane containing a plasticizer for the resin. Reducing shrinkage of phenolic foam composites Stagg, M.J., Stern, E.P. and Vidyarthi, S. (BPCO, Inc, Canada) US Pat 4 877 671 (31 October 1989) A foam composite comprising first and second oppositely disposed corrugated skins has a cured foam material between them. A reinforcement material is located at the interface between the core and each skin, the foam extending through the pores of this medium and bonding to both this medium and the skin. Bearing resin material Jinno, O. and Fukuoka, T. (Taiho Kogyo Co, Ltd, Toyota, Japan) US Pat 4 877 813 (31 October 1989) A resinous bearing material consists of at least one thermoplastic resin selected from the following: polyacetal, polyamide, polycarbonate, polyphenylene sulphide, polyethylene terephthalate and ultrahigh molecular weight polyethylene. 0.05-15 wt% short, unentangled, aromatic polyamide fibres are uniformly distributed therein. Water resistance additive for cementitious compositions Shah, V.A. (Air Products and Chemicals, Inc, Allentown, PA, USA) US Pat 4 878 948 (7 November 1989) A cementitious composition comprises cement, aggregate, water soluble or dispersible polymer and a water-resistant additive consisting of about 0.5-3.0 wt%, based on the cement, of a polyethylene glycol ester of a Cs-C22 fatty acid having an HLB value from 11 to 20. Laminated composite of a rigid polyisocyanurate substrate and metal, plastic, cellulose, glass, ceramic or combinations thereof Younes, U.E. (Arco Chemical Technology, Inc, Wilmington, DE, USA) US Pat 4 879164 (7 November 1989) A laminated composite formed in a mould consists of at least one layer of a rigid polyisocyanurate thermoset composition and at least one layer of metal, cellulose, plastic, glass, ceramic or combinations thereof. The polyisocyanurate composition is produced by
reacting in the mould a mixture of di- or poly-isocyanate; 2-50 parts by weight of a cyclic alkylene carbonate based on the isocyanate-carbonate mixture; and a soluble adduct of a tertiary amine and a cyclic alkylene carbonate as catalyst at a concentration of 0.005-3.0 wt% based on total composition. Alumina-zirconia ceramic Manning, W.R. (Champion Spark Plug, Toledo, OH, USA) US Pat 4 879 260 (7 November 1989) The title ceramic is formed from 85-99% of a mixture of particulate (less than 15 Ixm particle size) AI203 and ZrO 2 (between 0.25 and 4% ZrO 2 based on the weight of AI203 and ZrO 2 in the ceramic) bound together with 1-15% calcium-magnesium silicate glass containing 45-80% SiO2, 8-55% CaO and MgO and not more than 15% AI:O 3. Intumescent fire-retardant coating material Hastings, O.H. (Mahwah, N J, USA) US Pat 4 879 320 (7 November 1989) A fire-retardant coating material is described for coating housing and building frames. The material comprises a fluid, intumescent base consisting of a blowing agent, a charring agent, a film-forming binder and a solvent. A refractory fibrous material consisting of 40-55 wt% A1203, 40-55 wt% SiO 2 and 1-5 wt% of one or more of Fe203, TiO2, KO2, Na20 and ZrO2. The fibrous material has fibre lengths of at least 0.8-25 mm. Articles of synthetic polymeric materials and glass bead filler therefore Laroche, P. (Glaverbel, Brussels, Belgium) US Pat 4 879 321 (7 November 1989) Coated glass beads are claimed for use as a filler material in synthetic polymers. The coating accounts for 0.02-1 wt% based on the weight of the uncoated beads and consists of at least one coating containing at least two coating agents. These agents consist of at least one silicon-functional silane and at least one synthetic polymer with a glass transition temperature below 15°C or shock absorbing properties. The polymer is selected from the group consisting of polymers and copolymers of butadienes, acrylonitriles, acrylates and aliphatic urethanes. Cementitious dough or paste comprising at least one hydraulic element and at least one polymer latex Rirsch, E.A. and Barker, H.A. (Redland Technology Limited, Surrey, UK) US Pat 4 880 467 (14 November 1989) An uncured, cementitious, dough or paste comprises at least one hydraulic cement and at least one polymer latex selected from the group consisting of natural rubber latex and a latex of synthetic hydrophobic polymer and water. The polymer is present in amount of 1 to 20 parts by weight and the water in amount from 8 to 20 parts by weight, both per 100 parts by weight of the cement. Organic reinforcing fibres with bundle separation during fibre cutting and storage Cordova, C.W. and Cordova, D.S. (AlliedSignal Inc, Morris Township, Morris County, NJ, USA) US Pat 4 880 704 (14 November 1989) A fibre with improved partitioning properties is used for reinforcing plastic composites. The fibre is made of polyester, aliphatic polya-
COMPOSITES. MAY 1991
255
MATERIALS Cementitious composition Viles, R.F. (Fosroc International Limited, Birmingham, UK) US Pat 4 875 937 (24 October 1989) A rapid setting and hardening, dry cementitious composition that forms ettringite on mixing with water consists of 10-50% high alumina cement; at least 11.4% 13-anhydrite; 1-13% by weight relative to the high alumina cement of aluminium sulphate; 3-9% by weight relative the high alumina cement of a source of free lime; and at least 10% of a reactive filler. Ceramic bodies having a plurality of stress zones. Virkar, A.V. (Ceramatec Inc, Salt Lake City, UT, USA) US Pat 4 876 148 (24 October 1989) A green ceramic body contains at least two compositional zones; the first consists of sinterable ceramic particles and the second of particles with the same composition plus a significant content of ceramic fibres or whiskers with a lower thermal expansion coefficient than the sinterable particles of the first layer. On sintering and cooling, tensile and compressive stresses are generated in the first and second layers respectively. Building material and method of producing the building material Eichen, H.R. (Treestone Corporation, Ventura, CA, USA) US Pat 4 876 151 (24 October 1989) A two layer composite building material is claimed in which the first layer consists of a cured mixture of approximately 20 wt% cellulose fibres and 20 wt% sand; the remainder of the mixture being cement. The second layer consists of approximately 5 wt% cellulose fibres and 35 wt% sand; the remainder of the mixture being cement.
Process for the preparation of cyanate resinbased prepregs and films which maintain their tack Thorfinnson, B.S. (BASF Corporation, Parsippany, N J, USA) US Pat 4 876 153 (24 October 1989) A multiple layer composition has a first layer of a cyanate-functional, heat-curable resin and a second layer which is a silicone-coated release film containing an amount of metal catalyst which is effective to cause no greater than a 2.5 fold increase in the resin viscosity after storage at room temperature for one week. Composite wood structures bonded by poly(vinyl acetate) emulsion adhesives containing an alkoxysilane Witucki, G.L. and Plueddemann, E.P. (Dow Corning Corporation, Midland, MI, USA) US Pat 4 876154 (24 October 1989) A composite wood structure is bonded by a water-borne emulsion adhesive based on a poly(vinyl acetate) resin and 0.5-5.0 wt% alkoxysilane containing a plasticizer for the resin. Reducing shrinkage of phenolic foam composites Stagg, M.J., Stern, E.P. and Vidyarthi, S. (BPCO, Inc, Canada) US Pat 4 877 671 (31 October 1989) A foam composite comprising first and second oppositely disposed corrugated skins has a cured foam material between them. A reinforcement material is located at the interface between the core and each skin, the foam extending through the pores of this medium and bonding to both this medium and the skin. Bearing resin material Jinno, O. and Fukuoka, T. (Taiho Kogyo Co, Ltd, Toyota, Japan) US Pat 4 877 813 (31 October 1989) A resinous bearing material consists of at least one thermoplastic resin selected from the following: polyacetal, polyamide, polycarbonate, polyphenylene sulphide, polyethylene terephthalate and ultrahigh molecular weight polyethylene. 0.05-15 wt% short, unentangled, aromatic polyamide fibres are uniformly distributed therein. Water resistance additive for cementitious compositions Shah, V.A. (Air Products and Chemicals, Inc, Allentown, PA, USA) US Pat 4 878 948 (7 November 1989) A cementitious composition comprises cement, aggregate, water soluble or dispersible polymer and a water-resistant additive consisting of about 0.5-3.0 wt%, based on the cement, of a polyethylene glycol ester of a Cs-C22 fatty acid having an HLB value from 11 to 20. Laminated composite of a rigid polyisocyanurate substrate and metal, plastic, cellulose, glass, ceramic or combinations thereof Younes, U.E. (Arco Chemical Technology, Inc, Wilmington, DE, USA) US Pat 4 879164 (7 November 1989) A laminated composite formed in a mould consists of at least one layer of a rigid polyisocyanurate thermoset composition and at least one layer of metal, cellulose, plastic, glass, ceramic or combinations thereof. The polyisocyanurate composition is produced by
reacting in the mould a mixture of di- or poly-isocyanate; 2-50 parts by weight of a cyclic alkylene carbonate based on the isocyanate-carbonate mixture; and a soluble adduct of a tertiary amine and a cyclic alkylene carbonate as catalyst at a concentration of 0.005-3.0 wt% based on total composition. Alumina-zirconia ceramic Manning, W.R. (Champion Spark Plug, Toledo, OH, USA) US Pat 4 879 260 (7 November 1989) The title ceramic is formed from 85-99% of a mixture of particulate (less than 15 Ixm particle size) AI203 and ZrO 2 (between 0.25 and 4% ZrO 2 based on the weight of AI203 and ZrO 2 in the ceramic) bound together with 1-15% calcium-magnesium silicate glass containing 45-80% SiO2, 8-55% CaO and MgO and not more than 15% AI:O 3. Intumescent fire-retardant coating material Hastings, O.H. (Mahwah, N J, USA) US Pat 4 879 320 (7 November 1989) A fire-retardant coating material is described for coating housing and building frames. The material comprises a fluid, intumescent base consisting of a blowing agent, a charring agent, a film-forming binder and a solvent. A refractory fibrous material consisting of 40-55 wt% A1203, 40-55 wt% SiO 2 and 1-5 wt% of one or more of Fe203, TiO2, KO2, Na20 and ZrO2. The fibrous material has fibre lengths of at least 0.8-25 mm. Articles of synthetic polymeric materials and glass bead filler therefore Laroche, P. (Glaverbel, Brussels, Belgium) US Pat 4 879 321 (7 November 1989) Coated glass beads are claimed for use as a filler material in synthetic polymers. The coating accounts for 0.02-1 wt% based on the weight of the uncoated beads and consists of at least one coating containing at least two coating agents. These agents consist of at least one silicon-functional silane and at least one synthetic polymer with a glass transition temperature below 15°C or shock absorbing properties. The polymer is selected from the group consisting of polymers and copolymers of butadienes, acrylonitriles, acrylates and aliphatic urethanes. Cementitious dough or paste comprising at least one hydraulic element and at least one polymer latex Rirsch, E.A. and Barker, H.A. (Redland Technology Limited, Surrey, UK) US Pat 4 880 467 (14 November 1989) An uncured, cementitious, dough or paste comprises at least one hydraulic cement and at least one polymer latex selected from the group consisting of natural rubber latex and a latex of synthetic hydrophobic polymer and water. The polymer is present in amount of 1 to 20 parts by weight and the water in amount from 8 to 20 parts by weight, both per 100 parts by weight of the cement. Organic reinforcing fibres with bundle separation during fibre cutting and storage Cordova, C.W. and Cordova, D.S. (AlliedSignal Inc, Morris Township, Morris County, NJ, USA) US Pat 4 880 704 (14 November 1989) A fibre with improved partitioning properties is used for reinforcing plastic composites. The fibre is made of polyester, aliphatic polya-
COMPOSITES. MAY 1991
255