Purification of plasticizer and use thereof in a polymer production process and plant

Patent metadata

Field	Value
Publication number	US-10450438-B2
Application number	US-201515517440-A
Country	US
Kind code	B2
Filing date	Oct 2, 2015
Priority date	Nov 12, 2014
Publication date	Oct 22, 2019
Grant date	Oct 22, 2019

Abstract

The invention relates to purification of plasticizer, particularly for use in a polymer production process and plant. More particularly, the invention relates to purification of plasticizer, such as by gas stripping, for use in a process for in-line blending of polymer and plasticizer.

First claim

What is claimed is:

1. A process for producing a plasticized polymer, comprising the steps of:
(a) providing a reactor, a separator connected to the reactor, and a vessel containing a plasticizer;
(b) contacting in the reactor olefin monomers with a catalyst to form a polymer reactor effluent comprising a polymer-monomer mixture;
(c) passing the polymer reactor effluent from the reactor through the separator to form a polymer-rich phase and a polymer-lean phase;
(d) separating the polymer-lean phase from the polymer-rich phase;
(e) purifying the plasticizer by gas stripping to produce a purified plasticizer, the gas stripping comprising
(i) heating the plasticizer to a temperature of about 40° C. to about 300° C. to increase the vapor pressure of volatile impurities present in the plasticizer;
(ii) contacting the plasticizer with an inert gas using a contacting device to form a purified plasticizer and a vapor product comprising volatile impurities and the inert gas; and
(iii) separating the purified plasticizer from the vapor product using a separator device;

(f) feeding the purified plasticizer to the process after step (b) to form a plasticized polymer blend stream, wherein the purified plasticizer meets at least one of the following impurity removal characteristics, by concentration (wppm) relative to the plasticizer prior to purification:
(1) at least 90% of oxygen is removed;
(2) at least 90% of water is removed;
(3) at least 40% of an impurity having a relative volatility (α ip ) between 1×10 5 and 5×10 5 is removed;
(4) at least 65% of an impurity having an α ip between 5×10 5 and 1×10 6 is removed;
(5) at least 75% of an impurity having an α ip between 1×10 6 and 5×10 6 is removed; and
(6) at least 90% of an impurity having an α ip greater than 5×10 6 is removed, where α ip is the relative volatility of the impurity relative to the plasticizer at 200° C. and 1 atm; and

(g) obtaining a plasticized polymer from the plasticized polymer blend stream.

2. The process of claim 1 , wherein the purified plasticizer of step (e) is fed to the polymer-rich phase after step (d).

3. The process of claim 1 , wherein the plasticizer is continuously purified and continuously fed to the process.

4. The process of claim 1 , wherein the purified plasticizer meets all of the impurity removal characteristics (1) through (6).

5. The process of claim 1 , wherein the purified plasticizer meets at least one of the following impurity removal characteristics, by concentration (wppm) relative to the plasticizer prior to step (e):
(7) at least 99% of oxygen is removed;
(8) at least 98% of water is removed;
(9) at least 65% of an impurity having a relative volatility (α ip ) between 1×10 5 and 5×10 5 is removed;
(10) at least 85% of an impurity having an α ip between 5×10 5 and 1×10 6 is removed;
(11) at least 90% of an impurity having an α ip between 1×10 6 and 5×10 6 is removed; and
(12) at least 98% of an impurity having an α ip greater than 5×10 6 is removed, where α ip is the relative volatility of the impurity relative to the plasticizer at 200° C. and 1 atm.

6. The process of claim 5 , wherein the plasticized polymer contains at least 5 phr of purified plasticizer.

7. The process of claim 1 , wherein the plasticizer is a mineral oil.

8. The process of claim 1 , wherein the plasticizer is a Group I or Group II paraffinic oil.

9. The process of claim 1 , wherein the separator is a high-pressure separator, and the process further comprises a low-pressure separator downstream of the high-pressure separator.

10. The process of claim 1 , wherein the polymer being produced in the polymer production process is an ethylene-propylene-diene rubber containing 10-100 phr of a plasticizer.

11. The process of claim 1 , wherein the contacting device is at least one of a sparger, sintered disc, vapor distributor, in-line mixer, and stripping column.

12. The process of claim 1 , wherein the separator device is at least one of a gravity settler, de-entrainment device, and centrifugal separator.

13. The process of claim 1 , wherein the vapor product is vented to a gas absorber where volatile impurities are separated from the inert gas, and the inert gas is vented to the atmosphere.

14. The process of claim 1 , wherein the inert gas is at least one of nitrogen, a Group 18 element, and a saturated hydrocarbon.

15. The process of claim 1 , wherein the inert gas is a saturated hydrocarbon, and the vapor product comprising volatile impurities and the saturated hydrocarbon is vented to a fuel gas system or a flare system.

16. The process of claim 1 , wherein the temperature in step (i) is below at least one of the bubble point and the decomposition point of the plasticizer.

17. The process of claim 1 , wherein the temperature in step (i) is from about 150° C. to about 250° C.

18. The process of claim 1 , wherein the plasticizer is contacted with the inert gas in step (ii) at a pressure of about 0.1 atm to 4 atm absolute.

19. The process of claim 1 , wherein the mass rate of the inert gas is about 0.1% to about 20% of the mass rate of the plasticizer.

20. The process of claim 1 , further comprising after step (ii):
cooling the vapor product comprising volatile impurities and the inert gas to condense and form condensed impurities separated from the inert gas; and
collecting and recycling the condensed impurities.

21. The process of claim 1 , wherein a water is removed from the plasticizer before step (i).

22. The process of claim 1 , further comprising purifying the plasticizer before feeding to the process after step (b) by at least one of: fixed-bed sorption, chemical scavenger, distillation, liquid-liquid extraction, filtration, gravity settling, and centrifugation.

Assignees

• Exxonmobil Chemical Patents Inc

Inventors

• Soisson John P
• Friedersdorf Christopher B
• Hancock Kyle B
• Barsan Florin
• Canich Jo Ann M

Classifications

• C08J2323/16

  Ethene-propene or ethene-propene-diene copolymers · CPC title

• C08J3/18

  Plasticising macromolecular compounds (plasticisers C08K) · CPC title

• C08F2/01

  characterised by special features of the polymerisation apparatus used · CPC title

• C08F6/003 Primary

  from polymer solutions, suspensions, dispersions or emulsions without recovery of the polymer therefrom · CPC title

• C08K5/0016

  Plasticisers · CPC title