Saint-gobain Placo

Bpb Limited

Certainteed Gypsum, Inc.

Saint-gobain Placo S.a.s.

Robin Daniel Fisher

Jan Rideout

Laura Brooks

Jeffrey Hamilton Peet

Peter L Mayer

Devang Umesh Khariwala

Henri Van Damme

Richard Ian Walton

Henry Van Damme

Peter Mayer

Disclosed is a building board construction with increased surface strength. More specifically, increased nail pull strength is achieved via the application of an external surface coating. The surface coating is ideally applied to a paper faced gypsum building board. In one possible embodiment, the coating is formed from a water soluble polymer.

Building boards with increased surface strength

The product is produced from a settable aqueous calcium sulphate dispersion which has a water to solids ratio of less than 0.4 to 1, and has distributed therethrough lightweight hollow bodies having water-impervious surfaces (such as expanded polystyrene beads). The dispersion contains a hydratable cement (such as calcium sulpho aluminate) which is capable of hydration in the presence of the calcium sulphate dispersion. The hydratable cement is such that it reacts with excess water in the dispersion thereby enhancing the water resistance of the resulting product.

Lightweight gypsum products having enhanced water resistance

The present invention provides calcium sulphate-based product having reduced shrinkage after exposure to high temperatures, the product comprising gypsum, a pozzolan source e.g. in an amount between 4-27 wt %) and a metal salt additive in an amount between 0.5 and 10 wt %). The pozzolan source may be selected from a kaolinitic clay material, fly ash, rice husk ash, diatomaceous earths, volcanic ashes and pumices, micro-silica, silica fume and silicone oil, The metal salt additive may be a metal salt which decomposes between a temperature of 300-500&#xb0; C. to yield a metal oxide, e.g. magnesium nitrate.

Fire resistant calcium sulphate-based products

A calcium sulphate-based product including gypsum and a shrinkage resistance additive. The shrinkage resistance additive is a metal nitrate, hydroxide, acetate or sulphate and is preferably provided in an amount greater than 4 wt % (based on the amount of additive and gypsum). The additive may be a nitrate of an alkali metal (e.g. potassium), an alkaline earth metal (e.g. magnesium or calcium), a transition metal (e.g. iron or zinc) or aluminium.

Calcium sulphase-based products

The present invention provides a calcium sulphate-based product (e.g. a wall board) comprising gypsum, a pozzolan source such as a clay additive, rice husk ash or diatomaceous earth and a metal salt additive. The product may be produced by drying an aqueous slurry comprising calcined gypsum, the pozzolan source and the metal salt additive. The clay additive may be a kaolinitic clay. The metal salt additive may be a magnesium salt e.g. magnesium nitrate, magnesium chloride or magnesium hydroxide.

This invention relates to improved high temperature resistant calcium sulphate-based products e.g. gypsum wallboard products and, in particular, to products having reduced shrinkage at high temperatures. The invention provides calcium sulphate-based product comprising gypsum and a shrinkage resistance additive. The shrinkage resistance additive is melamine polyphosphate or melamine pyrophosphate.

Calcium sulphate-based products

The present invention provides calcium sulphate-based product having reduced shrinkage after exposure to high temperatures, the product comprising gypsum, a pozzolan source (e.g. in an amount between 4-27 wt %) and a metal salt additive (in an amount between 0.5 and 10 wt %). The pozzolan source may be selected from a kaolinitic clay material, fly ash, rice husk ash, diatomaceous earths, volcanic ashes and pumices, micro-silica, silica fume and silicone oil. The metal salt additive may be a metal salt which decomposes between a temperature of 300-500&#xb0; C. to yield a metal oxide, e.g. magnesium nitrate.

Fire-resistant calcium sulphate-based products

The invention provides a calcium sulphate-based product comprising a phosphate as additive for increased fire resistance. Particularly preferred phosphate additives may be those containing aluminum or ammonium ions.

Calcium sulphate-based products and methods for the manufacture thereof

A water-resistant calcium sulphate based body comprises a matrix of crystalline calcium sulphate anhydrite, crystals of the matrix being connected to one another by water-resistant phosphate bonding zones, optionally also containing aluminum. The body can be produced by impregnating a porous calcium sulphate with a source of phosphate ions (optionally containing aluminum), and then calcining. Alternatively, a paste comprising calcium sulphate and a source of phosphate ions (optionally containing aluminum) is heated or compressed to form a 'green body' and then calcined to produce the body.

Calcium sulphate-based products having enhanced water resistance

A method of producing gypsum building board, in which there is added, to an aqueous gypsum slurry containing a water swellable clay, a basic water-soluble polymer having preferential affinity for clay. The slurry is allowed to set so as to form a board. The basic water-soluble polymer may be, for example, a polyvinyl alcohol or a polymer consisting essentially of carbon, nitrogen and hydrogen and having amine groups (which may be primary, secondary, tertiary or quaternary) in the polymer backbone and/or in side chains thereof.

Growing community of inventors

Coventry, United Kingdom

Robin Daniel Fisher