Patent ID: 6863971

Claim:
A treated fibrous porous material obtainable from an untreated porous fibrous material containing original hydrophilic reactive sites by (i) treating the untreated porous fibrous material with a low viscosity organic solution consisting of: (a) a solvent selected from the group consisting of aromatics, aliphatics, ethers, esters, ketones, halogenated solvents and alcohols; (b) an isocyanate component being a mono- or poly-isocyanate; (c) an organic peroxide activated at elevated temperature; (d) an unsaturated polyester resin which is hydroxyl epoxy or carboxyl containing; and (e) styrene monomer; wherein said treated fibrous porous material comprises 80 to 99% (w/w) of said fibrous porous material; 1 to 12% (w/w) of said unsaturated polyester resin; 0.1-5% (w/w) of said styrene monomer; 0.4 to 3% (w/w) isocyanate; 0.05 to 0.2% (w/w) of said organic peroxide; and 0.75 to 5% (w/w) of said solvent; and (ii) forming a treated fibrous porous material whose original reactive hydrophilic sites are covalently bonded to said isocyanate via urethane, allophanate or biuret bonds, and said isocyanate is further coupled to said unsaturated polyester resin via urethane, allophanate or biuret bonds, wherein said treated fibrous porous material contains said organic peroxide activated at elevated temperature, said styrene monomer and said unsaturated polyester resin therein.