| 摘要 |
Shaped polyvinyl alcohol bodies are treated with a compound selected from the group consisting of dialdehydes, ketoaldehydes and acetals thereof. The term "polyvinyl alcohol" includes copolymers containing at least 80 per cent of the alcohol. Specified shaped bodies are fibres, filaments, tubes, envelopes and films and it is preferred that the body comprises a polyvinyl alcohol fibre which shrinks in water at 80 DEG C. not more than 5 per cent of its length. Specified compounds are glyoxal, succinic, malonic, adipic, alpha hydroxy adipic, suberic and pyruvic aldehydes and their acetals, phthalic, isophthalic, terephthalic, chloro- or nitro-substituted terephthalic, phenylmalonic and formylhydroxycinnamic aldehydes, diphenyl and diphenyldisulphide dialdehydes, mesitylene trialdehyde and phenylglyoxal, while mixtures of these compounds with each other or with other aldehydes such as formaldehyde may be used. The treatment with other aldehydes may also either precede or follow the dialdehyde treatment. They may be applied as vapours or in solution in water or in an organic solvent together with an acid catalyst in an amount of 0.5 to 25 per cent, or with a mixture of acid and inorganic salt in an amount of 5 to 25 per cent. The temperature of acetalization may be from 30 DEG to 90 DEG C. The shaped body may be heat-treated before the dialdehyde treatment, and may be reacted, after the dialdehyde treatment, with a compound which reacts with the carbonyl group, e.g. an amino compound or a phenol.
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