# US 10,766,974 B2 · Ultrafiltration of polyisoolefin copolymers and polyisoolefin copolymers with reduced oligomer content

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- Number: US 10,766,974 B2
- Document ID: US10766974B2
- Status: Granted
- Kind: B2
- Application number: 15/535,857
- Filed: 2015-07-07
- Published: 2017-12-07
- Granted: 2020-09-08
- Earliest claimed: 2014-12-19
- Applicants: ARLANXEO Singapore Pte. Ltd.
- Inventors: Conrad Siegers
- Web page: https://patentgrep.com/patent/US10766974B2

## CPC

- C08F 6/10: Removal of volatile materials, e.g. solvents {(C08F6/001, C08F6/003, C08F6/005, C08F6/006, C08F6/008, C08F6/02, C08F6/04 take precedence)}
- B01D 61/145: {Ultrafiltration}
- C08F 6/12: Separation of polymers from solutions
- C08F 210/12: with conjugated diolefins, e.g. butyl rubber
- C08J 3/24: Crosslinking, e.g. vulcanising, of macromolecules (mechanical aspects B29C35/00; crosslinking agents C08K)
- B01D 2315/10: Cross-flow filtration
- C08J 2323/22: Copolymers of isobutene; butyl rubber
- 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)
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)

## Abstract

A method of separating a polyisoolefin elastomer from non-polymeric components in an organic solvent involves ultrafiltration of a solution of the polyisoolefin elastomer and non-polymeric components in an organic solvent through a semipermeable membrane to substantially retain the polyisoolefin elastomer in a retentate and provide the non-polymeric components in a permeate. Advantageously, stabilizers for the polyisoolefin elastomer are retained in the retentate along with the polyisoolefin elastomer, permeate flux through the membrane is higher as concentration of the polyisoolefin elastomer in the solution increases up to a concentration limit, the separated polyisoolefin elastomer in the retentate has a molecular weight that can be substantially unchanged even when ultrafiltration is conducted at elevated temperature and the amount of polyisoolefin elastomer in the permeate is unmeasurable providing an oligomer-rich permeate uncontaminated by polyisoolefin elastomer. A process for curing a polyisoolefin copolymer involves reducing content of an oligomer to 900 ppm or less in a mixture of the oligomer and the polyisoolefin copolymer to produce an oligomer-depleted mixture, and adding a resin cure system to the oligomer-depleted mixture to cure the polyisoolefin copolymer.

## Claims

### Claim 1

A process for curing a polyisoolefin copolymer comprising isobutylene and isoprene units, the process comprising
reducing a content of an oligomer, the oligomer comprising one or both of a C13 and a C21 unsaturated cyclic oligomer, to 900 ppm or less in a mixture of the oligomer and the polyisoolefin copolymer comprising isobutylene and isoprene units to produce an oligomer-depleted mixture, and
adding a resin cure system to the oligomer-depleted mixture to cure the polyisoolefin copolymer.

### Claim 2 (depends on 1)

The process according to claim 1, further comprising reducing the content of the oligomer in the mixture by filtering the mixture of the oligomer and the polyisoolefin copolymer in an organic solvent through a semipermeable ultrafiltration membrane.

### Claim 3 (depends on 2)

The process according to claim 2, wherein the oligomer depleted mixture is a retentate of the filtration.

### Claim 4 (depends on 3)

The method according to claim 3, further comprising maintaining concentration of the polyisoolefin copolymer in the organic solvent at 2-40 wt. % based on total weight of the mixture.

### Claim 5 (depends on 3)

The process according to claim 3, wherein the filtering is performed at a temperature of from 30-200° C., optionally 40-130° C., optionally at a pressure in a range of from 2-50 bar.

### Claim 6 (depends on 3)

The process according to claim 3, wherein:
the organic solvent comprises one or more stabilizers for the polyisoolefin copolymer,
the one or more stabilizers comprise particulate solids insoluble in the organic solvent, non-permeating liquids immiscible in the organic solvent, or a combination thereof, and
at least one of the one or more stabilizers is retained in the retentate in an amount of from about 80-100 wt. % based on weight of the original amount of the at least one stabilizer in the organic solvent, optionally about 95-100 wt. %.

### Claim 7 (depends on 6)

The process according to claim 6, wherein the one or more stabilizers comprise an acid scavenger, optionally comprising a metal carboxylate, optionally in the form of a particulate solid, or a metal oxide or hydroxide, optionally comprising calcium stearate or sodium hydroxide, or a mixture of a metal carboxylate and a metal oxide or hydroxide.

### Claim 8 (depends on 3)

The process according to claim 3, wherein a molecular weight of the polyisoolefin is decreased by less than about 15% during the filtering step.

### Claim 9 (depends on 3)

The process according to claim 3, wherein the organic solvent comprises hexane, pentane, isohexane, isopentane or any mixture thereof and optionally the mixture comprises about 1-60 wt. % water based on the total weight of the mixture.

### Claim 10 (depends on 2)

The process according to claim 2, wherein the filtering comprises a crossflow ultrafiltration, optionally a constant volume crossflow ultrafiltration, optionally having a crossflow velocity of the solution across the ultrafiltration membrane in a range of from 0.5-10 m/s.

### Claim 11 (depends on 10)

The process according to claim 10, further comprising maintaining crossflow velocity (vCF) of the solution across the ultrafiltration membrane, concentration (yIIR) of the polyisoolefin copolymer in the solution and permeate flux (J) through the ultrafiltration membrane to satisfy Equation 1:
α
=
y
IIR
⁢
J
v
CF
Equation
⁢
⁢
1
where α is a unitless quantity greater than 3×10−7.

### Claim 12 (depends on 1)

The process according to claim 1, further comprising reducing the content of the oligomer in the mixture by precipitating the polyisoolefin copolymer from a solution of the mixture in a solvent.

### Claim 13 (depends on 1)

The process according to claim 1, wherein curing the polyisoolefin copolymer in the oligomer-depleted mixture increases cure state of the polyisoolefin copolymer by at least 8% compared to a cure state of the polyisoolefin copolymer when cured in a mixture having an oligomer content of more than 900 ppm.

### Claim 14 (depends on 1)

The process according to claim 1, wherein the content of the oligomer in the mixture is reduced to 250 ppm or less.

### Claim 15 (depends on 1)

The process according to claim 1, wherein the resin cure system includes a halogenated phenol formaldehyde resin.

### Claim 16 (depends on 15)

The process according to claim 15, wherein the resin cure system includes an activator.

### Claim 17 (depends on 15)

The process according to claim 15, wherein the resin cure system includes a metal oxide.

### Claim 18 (depends on 17)

The process according to claim 17, wherein the metal oxide is zinc oxide.

### Claim 19 (depends on 15)

The process according to claim 15, wherein the resin cure system includes a processing aid.

### Claim 20 (depends on 19)

The process according to claim 19, wherein the processing aid includes stearic acid.

### Claim 21 (depends on 15)

The process according to claim 15, wherein the amount of the resin is about 0.2 to about 10 parts by weight, based on the total weight of the polyisoolefin copolymer.

### Claim 22 (depends on 1)

The process according to claim 1, wherein resin cure system includes a phenol formaldehyde resin.

### Claim 23 (depends on 22)

The process according to claim 22, wherein the resin cure system includes an activator.

### Claim 24 (depends on 22)

The process according to claim 22, wherein the resin cure system includes a metal oxide.

### Claim 25 (depends on 24)

The process according to claim 24, wherein the metal oxide is zinc oxide.

### Claim 26 (depends on 22)

The process according to claim 22, wherein the resin cure system includes a processing aid.

### Claim 27 (depends on 26)

The process according to claim 26, wherein the processing aid includes stearic acid.

### Claim 28 (depends on 22)

The process according to claim 22, wherein the amount of the resin is about 0.2 to about 10 parts by weight, based on the total weight of the polyisoolefin copolymer.

### Claim 29 (depends on 1)

The process according to claim 1, wherein the resin cure system includes an alkyl phenol formaldehyde derivative.