Surface Whitening Research Articles

Surface Whitened, Shrink Resistant Wool Cloth of Improved Lightfastness

Chemically bleached woolen cloth was treated with a silicone based felt shrink resin and then with an acrylic resin that had a fluorescent whitening agent dissolved in it. The fluorescently surface whitened cloth thus obtained yellowed significantly more slowly, particularly when wet, then conventionally whitened cloth, in addition to being resistant to felt shrinkage. The two resin treatments were in a chlorinated organic solvent. The treated cloth had an acceptable handle and the treatment was fairly fast to gentle washing. A disadvantage was that the silicone treatment required 10-14 days for crosslinking on the cloth before the acrylic resin could be applied. Simultaneous treatment with both resins was successful only when using DC 109 silicone resin and dichloromethane as the solvent. Neither silicone nor acrylic resins yellowed the cloth upon application or caused accelerated photoyellowing afterwards. Surface whitening using an aqueous acrylic emulsion gave a satisfactory level of whiteness and rate of photoyellowing only when using a high concentration of resin on the cloth, which adversely affected its handle.