Compositions: coating or plastic – Coating or plastic compositions – Inorganic settable ingredient containing
Patent
1990-08-16
1992-03-31
Bell, Mark L.
Compositions: coating or plastic
Coating or plastic compositions
Inorganic settable ingredient containing
156 42, C04B 1442
Patent
active
051004747
DESCRIPTION:
BRIEF SUMMARY
This invention relates to a glass fibre reinforced plaster composition, methods of making the composition and to products made from the composition, comprising a glass-fibre reinforced plaster, a water-based phenolic resin, and additives to control the setting time of the composition.
In recent years there have been significant developments made in fire resistant, low smoke and toxic fume materials to satisfy a growing need for safe materials in public places and transport generally, e.g., aircraft industry, railways, underground and main line stations, BS 6853 1987 is now a British Standard Code of Practice for fire precautions in the design and construction of railway passenger rolling stock. In the last two years water-based phenolic resins have been developed for hand lay up methods of making glass-fibre reinforced plastics products, as the resin displays improved fire resistance and smoke emission compared with previously known resins.
According to one aspect of the present invention, there is provided a glass fibre-reinforced plaster composition comprising a settable fluid mix consisting of between 55% and 65% of a Gypsum plaster, between 20% and 30% by weight of mix of a water based phenol formaldehyde resin and between 3% and 5% by weight of mix of an acid hardener, and the mix also containing not less than 10% by weight of the mix of a fibre reinforcement.
The invention has the advantage that, by incorporating plaster with the phenolic resin, the resin content of the composition can be reduced, compared to the resin content of glass-fibre plastics products formed by the laying up technique, which results in a product which is less of a fire hazard and is also considerably cheaper to manufacture.
The invention has another advantage, in that the phenolic resin formulation contains 80% resin solids and 20% water. In the case of the resin/glass laminate glass-reinforced plastics material the 20% water retained after exothermy is driven off by evaporation usually in a drying chamber. As the water escapes from the hardening material pin holes are formed in the surface of the product which require filling with a wipe on/wipe off filler before application of a decorative surface coating. By incorporating plaster with the phenolic resin as in the preferred embodiment of the invention, the water contained in the phenolic resin plus added water is used to set the plaster and taken up by the process of hydrolysis. This occurs before exothermy of the resin and pin holing of the surface is prevented. The product cures more rapidly and does not require a heater chamber to complete the cure.
A preferred embodiment of the invention provides a glass-fibre reinforced plaster composition comprising a settable, fluid mix of between 55% and 65% of a plaster, between 20% and 30% by weight of mix of a water-based phenol formaldehyde resin, between 3% and 5% by weight of mix of an acid hardener, between 7% and 13% by weight of mix of water, and not less than 10% by weight of the mix of a glass fibre reinforcement.
In another aspect of the invention, the mix includes between 10% and 15% of a non combustible filler.
In yet another aspect of the invention, the mix includes between 10% and 20% of glass fibre reinforcement.
According to still other aspects of the invention as may be required for particular uses, the composition may include an acid hardening agent, a control agent based on calcium carbonate to control the Ph of the composition for pot life and setting time, and colouring agents.
In still another aspect of the invention, the mix may contain less than 15% water by weight of the mix and a water/plaster ratio of less than 25% by weight to provide a fluid workable mix to a consistency of thick cream suitable for hand lamination and hand-spray application.
In a preferred embodiment of the invention to provide a fire resistant material with low smoke and fume characteristics, a plaster reinforced composition comprises a mix which consists of 62.1% of gypsum plaster, 24.8% by weight of a water based phenolic resin, 4%
REFERENCES:
patent: 2664406 (1953-12-01), Armstrong
patent: 2871134 (1959-01-01), Loechl
patent: 2970127 (1961-01-01), Slayter et al.
patent: 3062670 (1962-11-01), Marzocchi et al.
patent: 4233368 (1980-11-01), Baehr et al.
Bell Mark L.
Green Anthony J.
Panel Craft-Benncroft Limited
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