摘要 |
A wet laid paper in which at least 1% by weight of the fibrous constituents are UF fibres made from an inorganic oxyacid radical modified UF resin. The inorganic oxyacid radicals are sulphite, phosphate, phosphite, or borate radicals and are present in such an amount that the UF fibres contain 0.2-15 inorganic oxyacid radicals per 100 methylene units. The modified resin is made by reacting urea with formaldehyde in the presence of a source of the oxyacid radicals. |