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Cellulose fibres such as wood pulp are made more suitable for reinforcement of cement products by a treatment which reduces their swelling in aqueous and alkaline mediums. The fibres are dispersed in water, allowed to swell, and impregnated with a solution of a titanium and/or zirconium chelate comp

Cellulose fibres such as wood pulp are made more suitable for reinforcement of cement products by a treatment which reduces their swelling in aqueous and alkaline mediums. The fibres are dispersed in water, allowed to swell, and impregnated with a solution of a titanium and/or zirconium chelate compound. After drying, the fibres are heated to react the chelate compound(s) with the hydroxyl groups on the cellulose fibres, preferably to produce cross-linking between hydroxyl group residues. The treated fibres are more stable in cement media, and, despite their increased hydrophobicity, are dispersible in cement slurries to give good web formation in the manufacture of cement products such as sheet. They impart improved flexural strength and modulus to cement products compared with untreated cellulose reinforcing fibres.

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A process for making cellulose fibres more suitable for cement reinforcement, characterised by dispersing the fibres in an aqueous medium which swells the fibres, impregnating the swollen fibres while dispersed in said aqueous medium with a titanium chelate compound and/or a zirconium chelate compou

A process for making cellulose fibres more suitable for cement reinforcement, characterised by dispersing the fibres in an aqueous medium which swells the fibres, impregnating the swollen fibres while dispersed in said aqueous medium with a titanium chelate compound and/or a zirconium chelate compound in aqueous solution under conditions which minimise hydrolysis of said chelate compound, mechanically extracting aqueous medium from said impregnated fibers to provide said fibers with a solids concentration of from about 20 to about 50 percent by weight, drying the hydroextracted fibers with a gaseous drying medium maintained at a temperature sufficiently low to minimise hydrolysis of the chelate compound by residual water in said fibers, and then effecting reaction between said chelate compound(s) and the hydroxyl groups on the cellulose fibres to form cross-links between residues of said hydroxyl groups on the surface and throughout the body of said fibres, the resulting cellulose reinforcing fibers having incorporated therein up to about 1%, by weight, of titanium, zirconium or mixtures thereof, based on the dry weight of cellulose fibres. A cellulose fibre product produced by the process of claim 1,