Preparation of concentrated latices by alternately flashing and centrifuging

Claim 1

THE PROCESS FOR PRODUCING A CONCENTRATED LATEX COMPRISING EMULSIFYING A MIXTURE OF WATER, EMULSIFYING AGENT AND SOLUTION OF A SYNTHETIC ELASTOMER DISSOLVED IN AN ORGANIC SOLVENT IN AN AMOUNT RANGING FROM 5 TO 25% BY WEIGHT OF ELASTOMER, STRIPPING THE ORGANIC SOLVENT FROM THE EMULSION AT ELEVATED TEMPERATURES AND PRESSURES BELOW CONDITIONS AT WHICH WATER BOILS BY A PLURALITY OF FLASHINGS WHEREIN EACH FLASHING REMOVES PROGRESSIVELY LESSER AMOUNTS OF SOLVENT, THE SAID EMULSION CONTAINING FROM 3 TO 15% BY WEIGHT OF ELASTOMER, FROM ABOUT 5 TO 30.0 PHR. OF AN EMULSIFYING AGENT, FROM ABOUT 300 TO 1900 PHR. OF AN ORGANIC SOLVENT FOR THE ELASTOMER AND ABOUT 500 TO 3500 PHR OF WATER, THE FIRST FLASHING BEING FOLLOWED BY A PRECONCENTRATION BY CENTRIFUGING AND A FINAL CENTRIFUGING FOLLOWING THE LAST FLASHING, RECOVERING AND RECYCLING THE AQUEOUS PHASES FROM THE CENTRIFUGING STEPS, THE SAID AQUEOUS PHASES INCLUDING EMULSIFYING AGENT AND LESS THAN A TOTAL OF 2% BY WEIGHT OF ELASTOMER, AND RECOVERING THE CONCENTRATED LATEX FROM THE FINAL CENTRIFUGING WHEREIN THE SOLIDS CONTENT RANGES FROM ABOUT 55 TO ABOUT 75% BY WEIGHT OF ELASTOMER.