GB924179A - Process for improving cellulose-containing materials - Google Patents

Abstract

Compositions for treating cellulosic fibre material (see Group IV(c) comprise: (a) an intermediate aminoplast condensation product, soluble in water but capable of being further condensed to an insoluble form, (b) formaldehyde, and (c) an oxidant capable of dispersion in water, which in aqueous phase has a strong binding capacity neither for alkalies nor for acids, and which accelerates the curing of the aminoplast on fibre material by the formation of oxidation products. The condensation products may be obtained from formaldehyde and cyanamide, dicyandiamide, biguanide, melamine, melam, melem, formoguanamine, acetoguanamine, urea or the like or mixtures of two or more of these. The formaldehyde may be supplied as an excess of formaldehyde from the formation of the aminoplast, or may be added separately. The oxidant may be hydrogen peroxide, adducts of hydrogen peroxide with such compounds as sodium perborate or urea, chlorine dioxide or an adduct thereof, e.g. that with pyridine, or salts of peroxymono- or peroxydi-sulphuric acid. In one example, the composition comprises also (a) a resin emulsion consisting of the adduct of ethylene oxide with ditertbutyl-paracresol, hexamethylolmelamine etherified with butanol, and water, (b) a solution of a copolymer of methacrylic acid and methyl methacrylate, sodium hydroxide and water, (c) a copolymer of isobutyl acrylate, vinylidene chloride and acrylic acid with sodium alphahydroxyoctadecanesulphonate, triethanolamine and isooctanol, (d) sodium hydroxide and (e) water.ALSO:Cellulosic fibre material is impregnated with an aqueous liquor containing: (a) an intermediate aminoplast condensation product, soluble in water but capable of being further condensed to an insoluble form, (b) formaldehyde, and (c) an oxidant capable of dispersion in water, which in aqueous phase has a strong binding capacity neither for alkalies nor for acids, and which accelerates the curing of the aminoplast on fibre material by the formation of oxidation products; and the aminoplast is thereafter condensed to an insoluble form on the fibre material in the presence of water. The fibrous material may be cotton in the form of loose material, knitted goods or woven materials, rayon fabric, or paper. The condensation products may be obtained from formaldehyde and cyanamide, dicyandiamide, biguanide, melamine, melam, melem, formoguanamine, acetoguanamine, urea or the like or mixture of two or more of these. The formaldehyde may be supplied as an excess of formaldehyde from the formation of the aminoplast, or may be added separately. The oxidant may be hydrogen peroxide, adducts of hydrogen peroxide with such compounds as sodium perborate or urea, chlorine dioxide or an adduct thereof, e.g. that with pyridine, or salts of peroxymono-or peroxydi-sulphuric acid. Part of the excess liquor may be removed by expression or centrifugation or by drying at room or moderately higher temperature to a moisture content of 20 to 50%, before condensing the aminoplast by storing for a prolonged period at room or moderately elevated temperature or by subjecting the material to a short treatment at an elevated temperature, whilst avoiding drying out. The treated material is protected from the attack of microorganisms and deterioration by weathering, and may have reduced swelling value, and improved abrasion-resistance. Paper impregnated by the process can be disintegrated and made into rot-resistant sheets of carton thickness. The impregnating liquor may also contain pigments to give a dyed product, or microbiocidal or microbiostatic substances. In an example, the pigment paste used comprises (a) a resin emulsion consisting of the adduct of ethylene oxide with ditertbutyl-paracresol, hexamethylolmelamine etherified with butanol, and water, (b) a solution of a copolymer of methacrylic acid and methyl methacrylate, sodium hydroxide and water, (c) a copolymer of isobutyl acrylate, vinylidine chloride and acrylic acid with sodium alphahydroxyocta decanesulphonate, triethanolamine and isooctanol, (d) sodium hydroxide and (e) water.