GB883486A - Improvements in laminated structures - Google Patents

Abstract

A synthetic resin is prepared by heating together at the boil a mixture of water, aqueous formaldehyde solution, sodium hydroxide, benzoguanamines, melamine and thiourea. After filtering, water and isopropanol are added and the whole maintained at 87 DEG C. and pH9 for 4 hours 20 minutes. The product is used for laminating (see Group VIII).ALSO:A synthetic or cellulose ester fibrous material, for use in a laminate (see Group VIII), is optically brightened, as follows. Acetyl-cellulose or polyamide fibres may be brightened with quaternary oxacyanine derivatives of the formula <FORM:0883486/IV (c)/1> in which A1 and A2 represent each a benzene or naphthalene residue, R1 and R2 represent each an alkyl or hydroxyalkyl group and X represents the radical of a strong acid. Polyamide fibres may be brightened with 1 : 3 : 4-oxdiazole compounds. Polyacrylonitrile fibres may be brightened by treatment in an aqueous bath with a dibenzimidazyl compound of the type <FORM:0883486/IV (c)/2> which is free from groups imparting solubility in water, and in which formula R1 is a bridge member containing at least one C=C group in conjugation with the double bonds of the imidazole rings, e.g. para-phenylene, 2-5-furylene, or an ethylene bridge, and the benzene rings R may contain substituents, e.g. methyl, methoxy or chlorine. Cellulose acetate fibres and polyester fibres may be brightened with a : b -di-[benzoxazolyl-(2)]-ethylene compounds free from groups imparting solubility in water, e.g. compounds of the formula <FORM:0883486/IV (c)/3> in which Z1 and Z2 each represent a hydrogen atom or a methyl group. The brightening agent may be fixed on the finished fibrous material. In the example, a fabric of fibres of terephthalic acid-polyglycol ester is treated in a bath containing water, ammonia, and a finely dispersed paste prepared from a : b -di-[5-methyl-benzoxazoylyl-(2)]-ethylene, and an addition product of about 30 mols of ethylene oxide with a mixture of saturated fatty alcohol, preponderantly C18.