Processes for the removal of rubber from non-
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).
1. 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. removing 80-95 weight % of bagasse from the miscella, 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;
d. increasing the relative amount of polar organic solvent as compared to non-polar organic solvent within the purified miscella so as to coagulate the rubber; and
e. producing solid purified rubber from the coagulated rubber where when said solid purified rubber contains 0.8 weight % volatile matter it also 0.1-4 weight % resin;
wherein at least (a)-(c) are conducted at a temperature or temperatures of 10-80° C. and a pressure of 35 to 1000 kPa, and
wherein the at least one non-polar organic solvent in (a) and (d) comprises hexanes.
2. The process of claim 1 , wherein the at least one non-polar organic solvent in (a) and (d) consists of hexanes.
3. The process of claim 1 , wherein the rubber coagulated in (d) has a molecular weight of at least 1 million grams/mole.
4. The process of claim 1 , wherein in (d) the relative amount of polar organic solvent as compared to non-polar organic solvent within the clarified rubber solution is increased by adding additional polar organic solvent.
5. The process of claim 1 , wherein in (d) the relative amount of polar organic solvent as compared to non-polar organic solvent within the clarified rubber solution is increased by removing non-polar organic solvent.
6. The process of claim 1 , wherein the rubber coagulated in (d) has a molecular weight of 1 million to 1.5 million grams/mole.
7. The process of claim 2 , wherein the rubber coagulated in (d) has a molecular weight of 1 million to 1.5 million grams/mole.
8. The process of claim 1 , wherein the rubber coagulated in (d) has a molecular weight of about 1.5 million grams/mole.
9. The process of claim 2 , wherein the rubber coagulated in (d) has molecular weight of about 1.5 million grams/mole.
10. The process of claim 1 , wherein the at least one polar solvent in (a) and (d) comprises acetone.
11. 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. removing 80-95 weight % of bagasse from the miscella, 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;
d. increasing the relative amount of polar organic solvent as compared to non-polar organic solvent within the purified miscella so as to coagulate rubber having a molecular weight of at least 1 million grams/mole; and
e. producing solid purified rubber from the coagulated rubber where when said solid purified rubber contains 0.8 weight % volatile matter it also contains 0.1-4 weight % resin;
wherein at least (a)-(c) are conducted at a temperature or temperatures of 10-80° C. and a pressure of 35 to 1000 kPa, and
wherein the at least one non-polar organic solvent in (a) and (d) comprises hexanes.
12. The process of claim 11 , wherein the at least one non-polar organic solvent in (a) and (d) consists of hexanes.
13. The process of claim 11 , wherein in (d) the relative amount of polar organic solvent as compared to non-polar organic solvent within the clarified rubber solution is increased by adding additional polar organic solvent.
14. The process of claim 11 , wherein in (d) the relative amount of polar organic solvent as compared to non-polar organic solvent within the clarified rubber solution is increased by removing non-polar organic solvent.
15. The process of claim 11 , wherein the rubber coagulated in (d) has a molecular weight of 1 million to 1.5 million grams/mole.
16. The process of claim 12 , wherein the rubber coagulated in (d) has a molecular weight of 1 million to 1.5 million grams/mole.
17. The process of claim 11 , wherein the rubber coagulated in (d) has a molecular weight of about 1.5 million grams/mole.
18. The process of claim 12 , wherein the rubber coagulated in (d) has molecular weight of about 1.5 million grams/mole.
19. 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. removing 80-95 weight % of bagasse from the miscella, 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;
d. increasing the relative amount of polar organic solvent as compared to non-polar organic solvent within the purified miscella so as to coagulate rubber having a molecular weight of 1-1.5 million grams/mole; and
e. producing solid purified rubber from the coagulated rubber where when said solid purified rubber contains 0.8 weight % volatile matter it also contains 0.1-4 weight % resin;
wherein at least (a)-(c) are conducted at a temperature or temperatures of 10-80° C. and a pressure of 35 to 1000 kPa, and
wherein the at least one non-polar organic solvent in (a) and (d) consists of hexanes and the at least one polar organic solvent in (a) and (d) comprises acetone.
20. The process of claim 19 , wherein in (d) the relative amount of polar organic solvent as compared to non-polar organic solvent within the clarified rubber solution is increased by removing non-polar organic solvent.