A simultaneous antimicrobial and shrink resistance treatment of wool woven fabrics using the polymeric biocide polyhexamethylene biguanide

Recently, a novel, effective, and commercially viable antimicrobial treatment for wool was reported that used a peroxymonosulfate/sulfite pretreatment and the biocide polyhexamethylene biguanide (PHMB). Given the polymeric nature of PHMB used in this antimicrobial treatment, this study investigated whether the treatment would also lead to shrink resistance of woven wool fabrics. It was shown that up to 5% PHMB (on mass of fabric) could be exhausted onto the pretreated wool at 40 °C. Under scanning electron microscope, PHMB was observed to coat the wool surface with no obvious interfiber bonding. PHMB finishing was durable to laundering, had little effect on the tensile strength of the fabrics and only slightly increased the bending rigidity. The finishing conferred strong antimicrobial activity to the fabrics and at the same time reduced felting shrinkage after laundering to an acceptable level. Thus, a single finishing process achieved two important functionalities for wool fabrics, antimicrobial activity and shrink resistance.