Method for forming wet-laid non-woven webs

Claim 1

The method of uniformly dispersing selected non-fibrillated fibers in a substantially binder free aqueous medium, a majority of the fibers being man made nonfibrillatable hydrophobic fibers of not less than about 1/4 inch in length and with a length to diameter ratio of between about 400:1 to about 700:1 including the steps of combining: water, a sufficient amount of the selected fibers for a dispersion having a fiber consistency of between about 0.35% to about 2% based on the bone dry weight of the fibers, and between about 0.007% to about 0.03% by weight of a wetting agent consisting of a selected combination of alkylaryl polyether alcohol (octylphenol series) and N-cyclohexyl-N-Palmitoyl-Taurine having the formula ##STR4## in a container to reduce the surface tension of the water to between about 30-35 dynes, and vigorously agitating the mixture in the container in the presence of air to create the tumbling vortex-free water surface conditions without the generation of any substantial amount of surface foam, thereby generating a steady state water/air emulsion in which the fibers are uniformly dispersed and in which the volume of air does not exceed about 4% of the volume of the water.

Claim 2

The method of uniformly dispersing selected non-fibrillated fibers in a substantially binder free aqueous medium, a majority of the fibers being man made nonfibrillatable hydrophobic fibers of not less than about 1/4 inch in length and with a length to diameter ratio of between about 400:1 to about 700:1 including the steps of combining: water, a sufficient amount of the selected fibers for a dispersion having a fiber consistency of between about 0.35% to about 2% based on the bone dry weight of the fibers, and between about 0.007% to about 0.03% by weight of a wetting agent consisting of a selected combination of alkylaryl polyether alcohol (octylphenol series) and N-cyclohexyl-N-Palmitoyl-Taurine having the formula ##STR4## in a container to reduce the surface tension of the water to between about 30-35 dynes, and vigorously agitating the mixture in the container in the presence of air to create the tumbling vortex-free water surface conditions without the generation of any substantial amount of surface foam, thereby generating a steady state water/air emulsion in which the fibers are uniformly dispersed and in which the volume of air does not exceed about 4% of the volume of the water.

Claim 12

The method of uniformly dispersing selected non-fibrillated fibers in a substantially binder free medium, a majority of the fibers being man made non-fibrillatable hydrophobic fibers of not less than about 1/4% in length and with a length to diameter ratio of between about 400:1 to about 700:1 including the steps of combining water, with a selected amount of a wetting agent consisting of N-cyclohexyl-N-Palmitoyl-Taurine having the formula ##STR7## in a container and vigorously agitating the two in the presence of air to create tumbling vortex-free water surface conditions, thereafter, while continuing the agitation, adding a predetermined quantity of alkylaryl polyether alcohol (octylphenol series) wetting agent during continued agitation of the medium, to reduce the water's surface tension to between about 30-35 dynes, to generate a water/air emulsion without any substantial amount of surface foam and in which the volume of air is less than about 4% that of the water, the total wetting agent being between about 0.007% to about 0.03% by weight of the water, followed by adding a sufficient amount of the fibers to the medium for a dispersion having a fiber consistency of between about 0.35% to about 2% based on the bone dry weight of the fibers, continuing to maintain the tumbling vortex-free water surface conditions until the fibers are uniformly dispersed in the water/air emulsion at the desired consistency and thereafter adding to the dispersion between about 0.0009% and about 0.06% by weight of long chain polyacrylamide having a molecular weight of at least 750,000 to about 6,000,000 to help stabilize the dispersion.

Claim 13

The method of uniformly dispersing selected non-fibrillated fibers in a substantially binder free medium, a majority of the fibers being man made non-fibrillatable hydrophobic fibers of not less than about 1/4% in length and with a length to diameter ratio of between about 400:1 to about 700:1 including the steps of combining water, with a selected amount of a wetting agent consisting of N-cyclohexyl-N-Palmitoyl-Taurine having the formula ##STR7## in a container and vigorously agitating the two in the presence of air to create tumbling vortex-free water surface conditions, thereafter, while continuing the agitation, adding a predetermined quantity of alkylaryl polyether alcohol (octylphenol series) wetting agent during continued agitation of the medium, to reduce the water's surface tension to between about 30-35 dynes, to generate a water/air emulsion without any substantial amount of surface foam and in which the volume of air is less than about 4% that of the water, the total wetting agent being between about 0.007% to about 0.03% by weight of the water, followed by adding a sufficient amount of the fibers to the medium for a dispersion having a fiber consistency of between about 0.35% to about 2% based on the bone dry weight of the fibers, continuing to maintain the tumbling vortex-free water surface conditions until the fibers are uniformly dispersed in the water/air emulsion at the desired consistency and thereafter adding to the dispersion between about 0.0009% and about 0.06% by weight of long chain polyacrylamide having a molecular weight of at least 750,000 to about 6,000,000 to help stabilize the dispersion.