Wetlaid nonwovens on high speed machines

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The term "polymeric surfactant" is defined as a molecule which contained a plurality, two or more, of both hydrophilic moieties and hydrophobic moieties.
This definition is derived from that of a simple surfactant, surface reactant agent, comprising a hydrophilic moiety and a hydrophobic moiety.
The difference in the hydrophilic and the hydrophobic portions of the polymeric surfactant molecules control the propensity of these molecules to arrange themselves in preferential molecular orientations at the interface between dissimilar substances.
In the case of the present invention, the polymer surfactants attach themselves to the surfaces of fibers at their interface with water as the suspending medium.
The key molecular feature is that the molecules contain both hydrophilic portions and hydrophobic portions.
The key distinction from simple surfactants is that these molecules would contain a multiplicity, two or more, of these types of groups.
The type of groups, as well as the relative positions of these ranges within specific molecules, can include a broad range of chemical moieties and distributions.
The associative thickener molecules have a multiplicity of hydrophobic and hydrophilic portions or "blocks" which form networks in an aqueous carrier medium, the exact nature of which is dependent upon the molecular shape and composition, as well as the nature of the solvent.
The formation of networks provides changes in the rheology of the solution that result in increases in viscosity; hence, the term "associative thickeners.
" Associative thickeners have been used in the paint industry for changing the rheological properties of paint formulations.
The present invention provides an improved method for forming fibrous webs from a water furnish containing textile length fibers which includes polymeric surfactant associative thickeners in the water making up the fiber furnish.
Such polymer surfactant associative thickeners have being developed primarily for use in the formation of latex paints