Method of increasing the strength of wet glass fiber mats made by the wet-laid process

Claim 1

In the manufacture of glass fiber mat products by the wet-laid process at a high rate of production wherein an aqueous dispersion of glass fibers which contains a surfactant dispersant is formed from bundles of glass fibers of about 1/4 to 3 inches in length and tertiary amine oxide or cationic quaternary ammonium dispersant compound at a concentration of about 5-500 ppm and at a fiber consistency of about 0.001 to 3%, which dispersion is passed through a matforming screen to form a freshly-prepared wet-mat of said fibers, the improvement which comprises: applying to said freshly-prepared wet-mat an anionic surfactant selected from the group consisting of (1) an anionic surfactant having at least (a) a hydrophobic segment containing from 8 to 30 carbon atoms selected from the groups consisting of alkyl, aryl, alkylaryl, substituted alkyl, and substituted alkenyl groups, said groups being straight or branched chain, saturated or unsaturated, and (b) an anionic segment selected from the groups consisting of carboxy, sulfate ester, phosphate ester, sulfonic acid and phosphonic acid, or (2) a soap selected from sodium, potassium, ammonium and alkylolammonium salts of higher C 10 -C 20 fatty acids, thereby to improve the wet-strength properties of said freshly-prepared wet-mat so that it can be readily handled and transferred during other steps in said process, into a finished glass fiber mat product.