Isolation of polymer resin from organic solution

Claim 2

A process for isolating polymer resin from organic solvent which comprises (a) admixing an aqueous slurry of from 0.5 to 20 weight percent solid polymer particles of a size ranging from 1 to 500 microns and one or more organic solvents, having dissolved therein about 1 to 50% by weight polymer resin to form an admixture; (b) volatilizing the organic solvents within the admixture while forming said admixture, the volatilization rate being sufficiently low to agglomerate the polymer resin in solution onto the solid polymer particles and form solid polymer granules; (c) maintaining the weight ration of water to total polymer within said admixture at a value in the range of about 1 to 50 during step (b); and (d) recovering water and solid polymer granules from the admixture.

Claim 3

A method as in claim 1 wherein the aqueous slurry contains about 0.5 to 10 weight % polymer particles.

Claim 4

A method as in claim 1 wherein the organic solvents contain about 10% to 30% by weight polymer resin.

Claim 5

A method as in claim 1 wherein the weight ratio of water to total polymer is maintained at a value within the range of about 2.5 to 20.

Claim 6

A method as in claim 1 wherein the organic solvents are selected from the group consisting of methylene chloride, 1,1,2,2-tetrachloroethane, 1 2-dichloroethylene, chloroform, 1,1,2-trichloroethane, pyridine, chlorobenzene, dichlorobenzene, benzene, xylene, toluene, mesitylene, hexane, heptane, and pentane.

Claim 7

A method as in claim 1 wherein admixing is achieved by a rotating impeller within an unbaffled vessel having a tip speed of at least about 5 feet per second.

Claim 8

A method as in claim 6 wherein said rotating impeller a tip speed of about 10 to 70 feet per second and the one or more organic solvents containing polymer resin is fed at an inlet located at the bottom of said vessel.

Claim 9

A method as in claim 1 wherein the solid polymer granules are recovered at a point near the top surface of the admixture.

Claim 10

A method as in claim 1 wherein volatilization of the one or more organic solvents is accomplished by maintaining the admixture at a temperature within the range of about 10° C. below to 30° C. above the boiling point of the organic solvents.

Claim 11

A method as in claim 1 wherein the one or more organic solvents are comprised of methylene chloride and volatilization is accomplished by maintaining the admixture at a temperature within the range of about 30° to 70° C. at atmospheric pressure.

Claim 12

A method as in claim 10 wherein the methylene chloride solution contains about 10 to 30 weight percent polycarbonate resin, the weight ratio of water to total polycarbonate within said admixture has a value within the range of 2.5 to 20 and the temperature of the admixture is maintained within the range of about 38° to 55° C. at one atmosphere pressure or less.

Claim 13

A method as in claim 11 wherein the polycarbonate is primarily cyclic, low molecular weight polycarbonate.

Claim 14

A method as in claim 1 wherein the organic solvents are comprised of toluene and volatilization is accomplished by maintaining the admixture at a temperature within the range of about 85° C. to 100° C. at atmospheric pressure.

Claim 15

A method as in claim 13 wherein the toluene solution contains about 10 to 30 weight percent polyphenylene ether resin, the weight ratio of water to total polyphenylene ether within said admixture has a value within the range of 2.5 to 20 and the temperature of the admixture is maintained below 100° C.

Claim 16

A method as in claim 13 wherein the toluene solution contains about 10 to 30 weight percent polystyrene resin, the weight ratio of water to total polystyrene within said admixture has a value within the range of 2.5 to 20 and the temperature of the admixture is maintained below 100° C.

Claim 17

A method as in claim 1 wherein the organic solvents are comprised of hexane and volatilization is accomplished by maintaining the admixture at a temperature within the range of about 60° to 75° C. at atmospheric pressure.

Claim 18

A method as in claim 16 wherein the hexane solution contains about 5 to 20 weight percent ethylene propylene rubber resin and the weight ratio of water to total ethylene-propylene-rubber within said admixture has a value within the range of 2.5 to 20.

Claim 19

A method as in claim 1 wherein said aqueous slurry of solid polymer particles is provided by a process comprising (a) admixing water with one or more organic solvents containing about 1 to 50 weight percent polymer resin to form an admixture; (b) volatilizing the organic solvents within the admixture to solidify the polymer resin within solution; and (c) maintaining the weight ratio of water to polymer resin within the admixture at a value above about 5.0 during step (b).

Claim 20

A method as in claim 18 wherein the weight ratio of water to polymer resin within said admixture is maintained at a value in the range of about 10 to 100.

Claim 21

A method as in claim 18 wherein the one or more organ solvents contain about 10% to 30% by weight polymer resin.

Claim 22

A method as in claim 18 wherein the organic solvents are selected from the group consisting of methylene chloride, 1,1,2,2-tetrachloroethane, 1,2-dichloroethylene, chloroform, 1,1,2-trichloroethane, chlorobenzene, pyridine, dichlorobenzene, benzene, hexane, pentane, heptane, xylene, toluene and mesitylene.

Claim 23

A method as in claim 18 wherein admixing is achieved a rotating impeller within a vessel having a tip speed of at least about 5 feet per second.

Claim 24

A method as in claim 22 wherein said rotating impeller has a minimum tip speed of about 10 to 70 feet per second.

Claim 25

A method as in claim 18 wherein the organic solvents contain about 10 to 30 weight percent polycarbonate, the weight ratio of water to polycarbonate resin has a value within the range of about 10 to 200 and volatilization is achieved by maintaining the admixture at a temperature within the range of about 0° to 35° C. above the boiling point of the organic solvents.

Claim 26

A method as in claim 18 wherein the organic solvents are comprised of toluene that contains about 10 to 30 weight percent polystyrene, the weight ratio of water to polystyrene resin has a value in the range of about 10 to 200 and volatilization is achieved by maintaining the admixture at a temperature within the range of about 95° to 100° C.

Claim 27

A method as in claim 18 wherein the organic solvents are comprised of toluene and contain about 10 to 30 weight percent polyphenylene ether, the weight ratio of water to polyphenylene ether resin has a value in the range of about 10 to 200 and volatilization is achieved by maintaining the admixture at a temperature in the range of 95° to 130° C.

Claim 28

A method as in claim 18 wherein the organic solvents are comprised of hexane and contain about 10 to 30 weight percent ethylene-propylene rubber, the weight ratio of water to rubber has a value within the range of 10 to 200 and volatilization is achieved by maintaining the admixture at a temperature within the range of 65° to 90° C.

Claim 29

A method as in claim 24 wherein the one or more organic solvents are comprised of methylene chloride and the temperature of the admixture is maintained within the range of about 45° C. to 75° C. at atmospheric pressure.

Claim 30

A method as in claim 1 wherein the one or more organic solvents are comprised of a methylene chloride solution of polycarbonate obtained from a polycarbonate polymerization process.

Claim 31

A method as in claim 1 wherein all steps are performed continuously.

Claim 32

A method as in claim 18 wherein the one or more organic solvents are comprised of a methylene chloride solution of polycarbonate obtained from a polycarbonate polymerization process.

Claim 33

A method as in claim 18 wherein all steps are performed continuously.

Claim 34

A method as in claim 1 wherein (a) the admixture is formed by feeding, with agitation, one or more organic solvents containing about 1 to 50% by weight polymer resin into a fixed volume of water at a rate within the range of about 0.5 to 10 weight % water per minute to provide a final concentration of solid polymer granules within the range of about 5-50 percent by weight; (b) the organic solvent is volatilized during formation of the admixture by maintaining the temperature of the admixture during feeding within the range of about 10° C. below to about 30° C. above the boiling point of the organic solvents; and (c) substantially all of the solid polycarbonate granules are recovered from the admixture upon volatilization of a substantial portion of the organic solvent.

Claim 35

A method as in claim 33 wherein the organic solvent contains about 10% to 30% by weight polycarbonate resin.

Claim 36

A method as in claim 34 wherein the final concentration of polycarbonate solids within the volume of water falls within the range of about 10 to 30% by weight.

Claim 37

A method as in claim 35 wherein the organic solvent containing polycarbonat is fed at a rate which provides a net feed within the range of about 1 to 5 Weight % per minute, based on water.

Claim 38

A method as in claim 36 wherein the organic solvent is methylene chloride and the admixture is maintained at a temperature in the range of about 35° to 50° C. at about 1 atmosphere pressure.

Claim 39

A method as in claim 37 wherein the methylene chloride solution contains about 10 to 30 weight percent polycarbonate and the feed rate of this methylene chloride falls within the range of about 0.5 to 2 weight percent per minute, based on water.

Claim 40

A method as in claim 1 wherein (aa) the aqueous slurry is obtained by feeding, with agitation, up to 10% of one or more organic solvents containing 1 to 50% by weight polymer resin into a fixed volume of water at a rate less than the feed rate of step (bb); (bb) the admixture is obtained by feeding, with agitation, the remaining portion of the organic solvents containing polymer resin into the aqueous slurry formed in step (aa) at a rate within the range of about 0.5 to 10 weight % water per minute to provide a final concentration of solid polymer granules within the range of 2-50 percent by weight; (cc) the organic solvent is volatilized during formation of the aqueous slurry and the admixture by maintaining their respective temperatures in the range of about 10° C. below to 30° C. above the boiling point of the organic solvents, and (dd) substantially all of the solid polycarbonate granules are recovered from the admixture upon volatilization of a substantial portion of the organic solvent.

Claim 41

A method as in claim 39 wherein 2.5 to 5% of the organic solvents are fed into volume of water during step (aa).

Claim 42

A method as in claim 39 wherein the organic solvent is comprised of methylene chloride and the aqueous slurry and admixture are maintained at temperatures in the range of about 35° to 50° C. at about one atmosphere.

Claim 43

A method as in claim 41 wherein the methylene chloride contains about 10 to 30 weight % polycarbonate resin, the final concentration of solid polycarbonate granules within the volume of water falls within the range of about 10 to 30 weight percent, the feed rate of methylene chloride during step (aa) falls within the range of about 0.1 to 0.5 weight percent water per minute and the feed rate of methylene chloride during step (bb) falls within the range of about 1 to 3 weight percent water per minute.