APPLYING PROTEASES TO CONFER IMPROVED SHRINK-RESISTANCE TO WOOL

The activity of an alkaline bacterial protease in conferring shrink-resistance to wool tops and woven cloth has been enhanced by pretreatment of the wool with sodium sulphite at pH 8.5–9.0. Among 16 proteases whose activities were compared, Esperase was found to be the most active, while causing the least damage when applied after sulphite treatment. None was found to confer adequate shrink-resistance to tops under these conditions without causing excessive damage. For some examples of woven cloth, sodium sulphite applied alone caused a significant reduction in shrinkage, and subsequent application of Esperase then afforded good washability. Excellent washability was obtained if the cloth was first oxidised with peroxymonosulphuric or monoperoxyphthalic acid before treating with Esperase.