# US 7,745,567 B2 · Process for stripping polymer dispersions

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- Number: US 7,745,567 B2
- Document ID: US7745567B2
- Status: Granted
- Kind: B2
- Application number: 11/978,325
- Filed: 2007-10-29
- Published: 2008-05-01
- Granted: 2010-06-29
- Earliest claimed: 2006-10-30
- Assignees: Rohm and Haas Company
- Inventors: James Kent Carpenter; Adam Loyack
- Web page: https://patentgrep.com/patent/US7745567B2

## CPC

- C08F 6/003: {from polymer solutions, suspensions, dispersions or emulsions without recovery of the polymer therefrom}
- B01D 1/06: Evaporators with vertical tubes
- B01D 5/006: {with evaporation or distillation}
- B01J 8/067: {Heating or cooling the reactor (B01J8/062 takes precedence)}
- B01J 2219/00038: Processes in parallel
- B01J 2219/0004: Processes in series
- B01J 2219/00085: Plates; Jackets; Cylinders
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS

## Abstract

A process for continuously stripping a polymer dispersion comprising a heat exchanger with minimal internal obstructions for the stripper. The process is particularly adapted to dispersions that are heat and shear sensitive. The process is able to extract hydrophobic VOC's more efficiently than a single, jacketed tube design.

## Claims

### Claim 1

A process for continuously stripping polymer dispersions with volatile substances comprising:
providing a polymer dispersion and steam wherein the dispersion comprises aqueous emulsion polymer and volatile organic compounds;
feeding the polymer dispersion and steam into a stripper;
removing at least a portion of the volatile organic compounds from the dispersion;
transferring the portion of the volatile organic compounds to the steam; and
separating the steam from the aqueous emulsion polymer in a separator vessel
wherein the stripper:
(a) has a ratio of surface area to volume of at least 10:1 l/m;
(b) further comprises a vacuum wherein the pressure in the vacuum ranges from 100 to 40,000 Pa; and
(c) is comprised of one or more heat exchangers wherein the heat exchanger is a shell and tube heat exchanger or a spiral heat exchanger.

### Claim 2 (depends on 1)

The process of claim 1 wherein the stripper is a single pass shell and tube heat exchanger.

### Claim 3 (depends on 1, 2)

The process of claim 1 or 2 wherein the velocity of the polymer dispersion and steam is at least 30 m/s within the stripper.

### Claim 4 (depends on 1, 2)

The process of claim 1 or 2 further comprising:
applying heat to the exterior of the tubes within the stripper.

### Claim 5 (depends on 1)

The process of claim 1 wherein the polymer dispersion is fed at a temperature greater than the water vapor temperature for the vacuum.

### Claim 6 (depends on 1)

The process of claim 1 wherein the pressure in the vacuum is between 2700 and 27,000 Pa.

### Claim 7 (depends on 1)

The process of claim 1 wherein the separator vessel comprises a jacket, coil, or external heat exchanger.