Processes for the removal of rubber from non-Hevea plants

Patent metadata

Field	Value
Publication number	US-9611334-B2
Application number	US-201615130050-A
Country	US
Kind code	B2
Filing date	Apr 15, 2016
Priority date	Mar 6, 2012
Publication date	Apr 4, 2017
Grant date	Apr 4, 2017

Abstract

Provided herein are organic solvent-based processes for the removal of rubber from non- Hevea plants such as guayule shrubs. By the use of the processes, solid purified rubber can be obtained that contains 0.05-0.5 weight % dirt, 0.2-1.5 weight % ash, and 0.1-4 weight % resin (when it has been dried so as to contain 0.8 weight % volatile matter).

First claim

What is claimed is:

1. A method of increasing the rubber recovery from guayule plant matter comprising:
A. utilizing briquettes comprising (i) compressed chopped plant matter having an average size of 1.5″ or less, comprising bagasse, rubber, resin, residual water, (ii) no more than 5 weight % guayule plant leaves, and (iii) at least one antioxidant, wherein the briquettes have a density that is 40-325% higher than the density of the non-compressed plant matter;
B. subjecting the briquettes to an organic solvent extraction process whereby the briquettes are mixed with at least one polar organic solvent and at least one non-polar organic solvent to form a slurry that contains plant matter, organic solvents and 0.5-10 weight % water, wherein the at least one polar organic solvent and at least one non-polar organic solvent are present in relative weight amounts of 50-90% and 10-50%, respectively; and
C. processing the slurry to remove bagasse and resin and recover at least 95-99% by weight of the rubber contained within the briquettes.

2. The method of claim 1 , wherein (B) and (C) comprise:
a. preparing a slurry from (i) the briquettes wherein the briquettes contain guayule plant matter comprising bagasse, rubber and resin, (ii) the least one non-polar organic solvent and (iii) the least one polar organic solvent, wherein the slurry contains 10-50% by weight plant matter from the briquettes, 50-90% by weight of (ii) and (iii) combined, and 0.5-10 weight % water from the plant matter;
b. removing a majority of the bagasse from the slurry to produce a miscella and a first bagasse portion;
c. optionally adding additional polar organic solvent, non-polar organic solvent or a combination thereof to the miscella to form a reduced viscosity miscella where any polar organic solvent and non-polar organic solvent may be the same or different than those utilized in (a) and where the amount of any additional polar organic solvent that is added is less than the amount that causes the rubber contained with the reduced viscosity miscella to coagulate;
d. removing 80-95 weight % of bagasse from the miscella resulting from (b) or (c) (based on the total weight of bagasse present in the miscella) to form a purified miscella and a second bagasse fraction wherein the majority of the bagasse that is removed has a particle size of less than 105 microns;
e. optionally treating the purified miscella to remove additional bagasse thereby producing a clarified rubber solution that contains 0.01-1% by weight of bagasse (based on the total weight of bagasse present in the slurry) wherein 90-99% of the additional bagasse that is removed has a particle size greater than 45 microns;
f. increasing the relative amount of polar organic solvent as compared to non-polar organic solvent within the clarified rubber solution or the purified miscella so as to coagulate the rubber; and
g. producing solid purified rubber from the coagulated rubber where when said solid purified rubber contains 0.8 weight % volatile matter it also contains 0.05-0.5 weight % dirt, 0.2-1.5 weight % ash and 0.1-4 weight % resin;
wherein at least (a)-(e) are conducted at a temperature or temperatures of 10-80° C. and a pressure of 35 to 1000 kPa.

3. The method of claim 2 , wherein the chopped plant matter is passed over a mesh screen having a mesh rating of 16 to 30 mesh to remove undersize material prior to compressing into briquettes.

4. The method of claim 2 , wherein at least one of steps (b) and (d) comprises the use of a centrifuge.

5. The method of claim 2 , wherein removing of the majority of bagasse in (b) comprises use of a screw press.

6. The method of claim 2 , wherein the non-polar organic solvent and any additional non-polar organic solvent comprises hexane or cyclohexane or the combination thereof, and the polar organic solvent and any additional polar organic solvent comprises acetone.

7. The method of claim 2 , wherein the (ii) at least one non-polar organic solvent of (a); and the (iii) at least one polar organic solvent of (a) are present in relative weight amounts of 50-90% and 10-50%, respectively.

8. An organic solvent-based process for the removal of rubber from guayule plant matter comprising:
a. utilizing a slurry containing (i) guayule plant matter, the guayule plant matter comprising bagasse, rubber and resin; (ii) at least one non-polar organic solvent; and (iii) at least one polar organic solvent, wherein the slurry contains 10-50% by weight plant matter, 50-90% by weight of (ii) and (iii) combined, and 0.5-10 weight % water from the plant matter, and wherein the at least one polar organic solvent and at least one non-polar organic solvent are present in relative weight amounts of 50-90% and 10-50%, respectively;
b. removing a majority of the bagasse from the slurry to produce a miscella and a first bagasse portion;
c. optionally adding additional polar organic solvent, non-polar organic solvent or a combination thereof to the miscella to form a reduced viscosity miscella where any polar organic solvent and non-polar organic solvent may be the same or different than those utilized in (a) and where the amount of any additional polar organic solvent that is added is less than the amount that causes the rubber contained with the reduced viscosity miscella to coagulate;
d. removing 80-95 weight % of bagasse from the miscella resulting from (b) or (c) (based on the total weight of bagasse present in the miscella) to form a purified miscella and a second bagasse fraction wherein the majority of the bagasse that is removed has a particle size of less than 105 microns;
e. optionally treating the purified miscella to remove additional bagasse thereby producing a clarified rubber solution that contains 0.01-1% by weight of bagasse wherein 90-99% of any additional bagasse that is removed has a particle size greater than 45 microns;
f. increasing the relative amount of polar organic solvent as compared to non-polar organic solvent within the clarified rubber solution or the purified miscella so as to coagulate the rubber; and
g. producing solid purified rubber from the coagulated rubber where when said solid purified rubber contains 0.8 weight % volatile matter it also contains 0.05-0.5 weight % dirt, 0.2-1.5 weight % ash and 0.1-4 weight % resin;

wherein at least (a)-(e) are conducted at a temperature or temperature of 10-80° C. and a pressure of 35 to 1000 kPa.

9. The process of claim 8 , wherein the (i) guayule plant matter comprises chopped plant matter.

10. The process of claim 8 , wherein the majority of bagasse removed from the slurry in (b) is 60-95 weight % of the bagasse contained within the slurry.

11. The process of claim 8 , wherein removing of the majority of bagasse in (b) comprises use of a screw press.

12. The process of claim 8 , wherein removing of the majority of bagasse in (b) comprises use of a counter-current extractor and the majority is 70-95 weight %.

13. The process of claim 8 , wherein the plant matter in the slurry has been in contact with the solvents (ii) and (iii) for 0.3 to 3 hours prior to (b).

14. The process of claim 8 , wherein at least one of (b) or (d) comprises use of a centrifuge.

15. The process of claim 14 , wherein the centrifuge is a disk centrifuge operated a speed sufficient to generate a g force of 4,000-12,000.

16. The process of claim 8 , wherein at least a portion of at least one of the first bagasse portion and the second bagasse portion is recycled into the slurry, allowing for transfer of additional rubber or resin that is associated with the bagasse portion(s) into the miscel

Assignees

• Bridgestone Corp

Inventors

• Huang Yingyi
• Smale Mark W
• White Robert
• Mouri Hiroshi
• Cole William M

Classifications

• C08G83/00

  Macromolecular compounds not provided for in groups C08G2/00 - C08G81/00 · CPC title

• C08L2205/03

  containing three or more polymers in a blend · CPC title

• C08C2/02 Primary

  Purification · CPC title

• C08C3/02 Primary

  Purification · CPC title

• C08C4/00

  Treatment of rubber before vulcanisation, not provided for in groups C08C1/00 - C08C3/02 · CPC title