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Reinforced composites
strength is found in two directions at right angles.. Applications in bitumen and plasucs composites are cited.
Yarns and like fibre assemblies
Benson, W. and Short, G. (Cotton, Silk and Man-Made Fibres Research Ass) UK Patent Specification,
1,240,470 (28 July 1971)
A yarn is made using the nip between two surfaces moving continuously in opposite directions causing fibres to accumulate in the nip with their axes substantially at right angles to the direction of movement of the surfaces. At the surface fluid flow causes the fibre to twist and it may be withdrawn as a continuous twisted strand. Carbon fibres which cannot be spun conventionally have been prepared in yarn form and used successfully .in metallic composites.
Method for producing a composite steel substance composed of fibres and elaslie materials
(Toray
UK Patent 1,241,382 (4 August
Industries Inc)
Specification, 1971)
A sheet is formed from b u n d l e s of fibres bonded longitudinally. T h e bonding a g e n t is solvent extracted and the sheet impregnated with afirst polymer solution. Further impregnation with an elastomeric polymer solution follows and then removal of the first polymer. T h e resultant composite is a good substitute for leather.
Production of carbonized and graphitized fibres
stabilit), at elevated temperatures. T o maintain these composite properties the addition of 0.5 to 5-0 wt% of an antioxidant, usually a phenolic compound, is required, otherwise deterioration at elevated temperatures occurs. Sheets and laminates of resinous and fibrous materials
(E. I. Du Pont de Nemours & Co) UK
Patent Specification, August 1971)
1,242,157 (11
A sheet of fibrous material is impregnated with a polyamide precursor, alone or containing a dispersion of 0-5-20wt% (based on precursor) inert, thermally-stable, colloidal particles. T h e use of carbon black, asbestos or amorphous silica effects a reduction in the void content of the laminate, improving dimensional stability a n d flexural strength.
Production filaments
of
continuous
carbon
Higgins, F. J. (Courtaulds Ltd) UK
Patent Specification, August 197.1)
1,242,388 (11
T h e continuous production of carbon filaments is described in which a' tow of organic filaments is passed through a pre-heating zone at 200-300°C in air enriched with oxygen or other gases capable of oxidizing organic filaments or nitrogen. T h e t o w then passes under tension over free runnlng rollers in a main heating zone under the same conditions for a period of ½-4 h before being carbonized for a similar time in an inert atmosphere between 1000°C and 2000°C. For graphitization a further heating zone preferably in excess of 2500°C is required.
(Monsanto Co) UK Patent Specification, 1,241,937 (4 August 1971) Carbonized or graphitized fibre or fibrOus web is prepared by heating at least part of a web formed from acrylonitrile or a copolymer with an alpha monoethylenically unsaturated copolymerizable monomer, or natural or regenerative cellulose or an aromatic polyamide. Heating in an atmosphere containing oxygen at 180-550°C is followed by heating to 700-1200°C in an oxygen-free atmosphere or further to 3600°C for a graphitized fibre. A lazer beam is used for the last two processes. T h e flexible carbonized or -graphitized fibres have been used in plastics composites.
Stabilized compositions of polypropylene and asbestos
(Farbewerke Hoeschst Akt-Ges) UK
Patent Specification, August 1971)
1,242,124 (ll
Composites of 30-90 parts by weight of crystalline polypropylene and 10-70 parts by weight of asbesfos are described. T h e addition of asbestos to polypropylene improves hardness, stiffness and especially the dimensional
264
COMPOSITES December 1971
Production of fibrous sheet compoaents
Ringe, W. (Hauni-Werbe Korber & Co) UK Patent Specification, 1,242,417
(11 August 1971)
T h e invention concerns the edge-zone treatment of glass fibre, sheet material in the production of resin-bonded composites. Glass fibre mats are placed in an overlapping m a n n e r and the edge zone is mechanically thinned to av'oid thickening at the overlap zones. T h e edge zone is supported by a feeder and glass fibres are removed in a direction perpendicular to the direction of feeder movement. Equipment is described to perform this operation.
Laminate structure having a high reverse impact strength
(General T y r e & R u b b e r Co) UK
Patent Specification, August 1971)
1,242,459 (11
T h e invention is a laminate possessing high reverse impact strength comprising layers of a glass-fibre-reinforced thermoset. Alternate layers and the outermost layers of the laminate contain a uniform dispersion of
particles of a solid elastomer. Elastomers particles provide points of local flexing in an otherwise rigid matrix where point injected energy from light impacts may be expended or absorbed. Conventional laminates crack easily under such impacts. Production of glass-fibre phenolic resin composites
reinforced
Morris, C. E. M. (Imperial Chemical Industries Ltd) UK Patent Specifica-
tion, 1,243,098 (18 August 1271)
A method of forming a glass-fibrereinforced phenolic resin is described. Glass fibres are first treated with a wetting promoter and then with uncured phenolic-resin composition. T h e wetting promoter is a specified organic alcohol, ether or an aminophenyl compound, which improves the resin-glass fibre adhesion. The composites have improved strength, particularly flexural modulus. Improvements in or relating to ehemical finishes for glass reinforcing materials
(Fibreglass Ltd) UK Patent Specification, 1,243,629 (25 August 1971) T h e limiting factor in the flexural strength of glass-reinforced resin composites is usually the strength of the glass-resin bond. Glass reinforcing materials treated with a reaction product of triethanolamine and glycidoxypro.pyl trimethoxysilane and used in resin composites resulted in markedly improved flexural strength. Reinforced structural plastics
Lubowitz, H. R. a n d Kendrick, W. D. ( T R W Inc) UK Patent Specification,
1,243,643 (25 August 1971)
Reinforcing materials such as carbon, silicates or borides are impregnated with a curable end-capped polyimide precursor obtained by reacting a polyamine, a polyanhydride and an end-capping monoanhydride. This precurs.o¢ gives a r a p i d cure and no precautions are necessary at the impregnation stage to exclude air. T h e final cure simply consists of applying heat and pressure to the structures. Applications include leading edges for aircraft or nose cones for space vehicles. Reinforced composites
Ball, C. G. and Grimm, A. C. (United States Steel Corp) UK Patent gpecifi-
cation, .1,243,672 (25 August 1971)
T h e invention is a reinforced concrete composite containing randomly distributed reinforcing filaments, sufficient to reinforce the concrete and restrict crack propagation. T h e non-round' discontinuous filaments may be glass copper, lead, steel or aluminium. Nonr o u n d filaments yield greater reinforcement than round filaments, also, fibre, nylon, titanium, tungsten, dispersion in the concrete matrix is easier. Reinforcing filaments may be used exclusively or in conjunction with conventional steel mesh or bars.
Yarns and like fibre assemblies
Benson, W. and Short, G. (Cotton, Silk and Man-Made Fibres Research Ass) UK Patent Specification,
1,240,470 (28 July 1971)
A yarn is made using the nip between two surfaces moving continuously in opposite directions causing fibres to accumulate in the nip with their axes substantially at right angles to the direction of movement of the surfaces. At the surface fluid flow causes the fibre to twist and it may be withdrawn as a continuous twisted strand. Carbon fibres which cannot be spun conventionally have been prepared in yarn form and used successfully .in metallic composites.
Method for producing a composite steel substance composed of fibres and elaslie materials
(Toray
UK Patent 1,241,382 (4 August
Industries Inc)
Specification, 1971)
A sheet is formed from b u n d l e s of fibres bonded longitudinally. T h e bonding a g e n t is solvent extracted and the sheet impregnated with afirst polymer solution. Further impregnation with an elastomeric polymer solution follows and then removal of the first polymer. T h e resultant composite is a good substitute for leather.
Production of carbonized and graphitized fibres
stabilit), at elevated temperatures. T o maintain these composite properties the addition of 0.5 to 5-0 wt% of an antioxidant, usually a phenolic compound, is required, otherwise deterioration at elevated temperatures occurs. Sheets and laminates of resinous and fibrous materials
(E. I. Du Pont de Nemours & Co) UK
Patent Specification, August 1971)
1,242,157 (11
A sheet of fibrous material is impregnated with a polyamide precursor, alone or containing a dispersion of 0-5-20wt% (based on precursor) inert, thermally-stable, colloidal particles. T h e use of carbon black, asbestos or amorphous silica effects a reduction in the void content of the laminate, improving dimensional stability a n d flexural strength.
Production filaments
of
continuous
carbon
Higgins, F. J. (Courtaulds Ltd) UK
Patent Specification, August 197.1)
1,242,388 (11
T h e continuous production of carbon filaments is described in which a' tow of organic filaments is passed through a pre-heating zone at 200-300°C in air enriched with oxygen or other gases capable of oxidizing organic filaments or nitrogen. T h e t o w then passes under tension over free runnlng rollers in a main heating zone under the same conditions for a period of ½-4 h before being carbonized for a similar time in an inert atmosphere between 1000°C and 2000°C. For graphitization a further heating zone preferably in excess of 2500°C is required.
(Monsanto Co) UK Patent Specification, 1,241,937 (4 August 1971) Carbonized or graphitized fibre or fibrOus web is prepared by heating at least part of a web formed from acrylonitrile or a copolymer with an alpha monoethylenically unsaturated copolymerizable monomer, or natural or regenerative cellulose or an aromatic polyamide. Heating in an atmosphere containing oxygen at 180-550°C is followed by heating to 700-1200°C in an oxygen-free atmosphere or further to 3600°C for a graphitized fibre. A lazer beam is used for the last two processes. T h e flexible carbonized or -graphitized fibres have been used in plastics composites.
Stabilized compositions of polypropylene and asbestos
(Farbewerke Hoeschst Akt-Ges) UK
Patent Specification, August 1971)
1,242,124 (ll
Composites of 30-90 parts by weight of crystalline polypropylene and 10-70 parts by weight of asbesfos are described. T h e addition of asbestos to polypropylene improves hardness, stiffness and especially the dimensional
264
COMPOSITES December 1971
Production of fibrous sheet compoaents
Ringe, W. (Hauni-Werbe Korber & Co) UK Patent Specification, 1,242,417
(11 August 1971)
T h e invention concerns the edge-zone treatment of glass fibre, sheet material in the production of resin-bonded composites. Glass fibre mats are placed in an overlapping m a n n e r and the edge zone is mechanically thinned to av'oid thickening at the overlap zones. T h e edge zone is supported by a feeder and glass fibres are removed in a direction perpendicular to the direction of feeder movement. Equipment is described to perform this operation.
Laminate structure having a high reverse impact strength
(General T y r e & R u b b e r Co) UK
Patent Specification, August 1971)
1,242,459 (11
T h e invention is a laminate possessing high reverse impact strength comprising layers of a glass-fibre-reinforced thermoset. Alternate layers and the outermost layers of the laminate contain a uniform dispersion of
particles of a solid elastomer. Elastomers particles provide points of local flexing in an otherwise rigid matrix where point injected energy from light impacts may be expended or absorbed. Conventional laminates crack easily under such impacts. Production of glass-fibre phenolic resin composites
reinforced
Morris, C. E. M. (Imperial Chemical Industries Ltd) UK Patent Specifica-
tion, 1,243,098 (18 August 1271)
A method of forming a glass-fibrereinforced phenolic resin is described. Glass fibres are first treated with a wetting promoter and then with uncured phenolic-resin composition. T h e wetting promoter is a specified organic alcohol, ether or an aminophenyl compound, which improves the resin-glass fibre adhesion. The composites have improved strength, particularly flexural modulus. Improvements in or relating to ehemical finishes for glass reinforcing materials
(Fibreglass Ltd) UK Patent Specification, 1,243,629 (25 August 1971) T h e limiting factor in the flexural strength of glass-reinforced resin composites is usually the strength of the glass-resin bond. Glass reinforcing materials treated with a reaction product of triethanolamine and glycidoxypro.pyl trimethoxysilane and used in resin composites resulted in markedly improved flexural strength. Reinforced structural plastics
Lubowitz, H. R. a n d Kendrick, W. D. ( T R W Inc) UK Patent Specification,
1,243,643 (25 August 1971)
Reinforcing materials such as carbon, silicates or borides are impregnated with a curable end-capped polyimide precursor obtained by reacting a polyamine, a polyanhydride and an end-capping monoanhydride. This precurs.o¢ gives a r a p i d cure and no precautions are necessary at the impregnation stage to exclude air. T h e final cure simply consists of applying heat and pressure to the structures. Applications include leading edges for aircraft or nose cones for space vehicles. Reinforced composites
Ball, C. G. and Grimm, A. C. (United States Steel Corp) UK Patent gpecifi-
cation, .1,243,672 (25 August 1971)
T h e invention is a reinforced concrete composite containing randomly distributed reinforcing filaments, sufficient to reinforce the concrete and restrict crack propagation. T h e non-round' discontinuous filaments may be glass copper, lead, steel or aluminium. Nonr o u n d filaments yield greater reinforcement than round filaments, also, fibre, nylon, titanium, tungsten, dispersion in the concrete matrix is easier. Reinforcing filaments may be used exclusively or in conjunction with conventional steel mesh or bars.