| In Part A, laminates were thermally bonded with cotton cores placed between nonwoven substrates. Six laminates were repellent finished to improve barrier properties. Laminates were tested for properties required in medical and hygiene applications. Finished laminates had better barrier properties and higher drapability, but lower strength. The laminate having 80% cotton had the best mechanical hand properties in KES analyses. Laminates having spunbond web had the highest MVTR. The Wilcoxon Signed Rank test was used to determine statistically significant differences in the properties of the unfinished and finished laminates at the 0.05 level. In comparing cotton laminates with commercial surgical gowns, it appeared that the SMS gown had better strength than cotton laminates which displayed better barrier properties. The SMS and cotton laminates failed the blood test. The Pro/Vent{dollar}spcircler{dollar} gown was found to be better than cotton laminates and SMS gown in all properties.; Part B attempted to overcome the two main deficiencies of Part A regarding stringent barrier requirements and higher processing speeds. The thermal bonding and preliminary adhesive bonding used Polytetrafluoroethylene Tetratex{dollar}rmsp{lcub}TM{rcub}{dollar} and Polyethylene Exxaire{dollar}spcircler{dollar} microporous films and point calendered the laminates at ambient and slightly elevated temperatures. While a few of these laminates passed the synthetic blood penetration test, none passed the more rigorous viral penetration test.; Subsequently, an adhesive melt blown line was used to coat the constituent layers and the laminates were smooth and point bonded at ambient temperature. The adhesive smooth bonded laminates passed the rigorous blood and viral penetration, had good moisture vapor transmission rates, had much faster processing speeds, and had no restrictions on the number of layers in a laminate. Statistically significant differences between smooth and point bonded laminates at the 0.05 level was determined by the Wilcoxon Signed Rank Test.; Darcy's equation and Textile Research Institute's Liquid-Air Displacement Apparatus was used to theoretically and experimentally, respectively, determine the permeability constant of cotton laminates. Both techniques determined that laminates having two spunbond webs were the most permeable followed by laminates having one spunbond and one melt blown layer followed by laminates having both melt blown layers. |
