Preparation of crosslinked polymer latex from aqueous emulsion of solvent/polymer solution of precursor latex particle size

摘要

The preparation of aqueous latices from solvent dispersions of elastomers and other high polymer compositions has presented problems including excessive viscosity during processing and foaming and coagulation, which have produced losses and increased costs. Herein combinations of steps are disclosed which reduce or eliminate various of these problems; enable the preparation of latices from high solids, high viscosity cements as well as from high solids cements of low molecular weight polymer; enable preparation of latices of grafted or filler extended or filler reinforced elastomers; enable preparation of latices of low molecular weight polymer which are then modified to materially increase the molecular weight of the polymer and/or the latex particle size; and enable the preparation of improved latices both dilute and of high solids contents, which are useful for example for adhesive and film forming purposes. The process in common with that of related copending applications is characterized, inter alia, by the establishment of a flow of latex through the separating zone and the impingement on said flow of the coalesced latex droplets from the solvent vapor stream in which they are delivered to the separator, and in certain embodiments by the use of particular additive materials. New combinations of steps and of apparatus for performing the same are also disclosed and claimed. The part of the process herein claimed is concerned with the preparation of a cross-linked polymer latex from an emulsion of solvent/polymer solution of precursor latex particle size, by converting the emulsion into an aerosol with the aid of steam, separating the resulting latex phase from the gaseous phase of the aerosol, adding cross-linking agent to the latex phase, subjecting the combination to homogenization sufficient to establish intimate association between the particles and the cross-linking agent, and effecting reaction of the cross-linking agent with the polymer of the latex. The process disclosed is applicable to the production of latices from specified rubbery and non-rubbery polymer compositions, and certain of such latices are new and useful products also claimed therein.