Claims
- 1. A process for preparing a linear block copolymer having a number average molecular weight of 80,000 to 200,000 containing 5 or more alternating blocks of (A) polymerized styrene or alkyl styrene units, and (B) polymerized conjugated diene units, terminated by the (A) units, and comprising at least about 70% by weight of the blocks (A) and not more than about 30% by weight of the blocks (B), which process comprises anionic dispersion polymerization in a paraffinic or monoolefin dispersing medium which is not a solvent for the polymer in the presence of a block copolymer dispersant containing A and B units which produces the linear block polymer at a concentration of 20 to 40 weight percent in the dispersing medium.
- 2. The process of claim 1 in which the A blocks consist of polymerized styrene units and the B blocks consist of polymerized butadiene units.
- 3. The process of claim 1 in which the linear block copolymer has the configuration A-B-A-B-A.
- 4. The process of claim 2 in which the linear block copolymer has the configuration A-B-A-B-A.
- 5. The process of claim 1 in which said linear block copolymer has a number average molecular weight of 100,000 to 150,000.
- 6. The process of claim 2 in which said linear block copolymer has a number average molecular weight of 100,000 to 150,000.
- 7. The process of claim 4 in which said linear block copolymer has a number average molecular weight of 100,000 to 150,000.
- 8. The process of claim 1 wherein the dispersing medium is isobutane.
- 9. The process of claim 7 wherein the dispersing medium is isobutane.
- 10. The process of claim 3 in which the A blocks consist of polymerized para-methylstyrene units.
- 11. The process of claim 10 in which the B blocks consist of polymerized butadiene units.
- 12. The process of claim 10 in which the B blocks consist of polymerized isoprene units.
- 13. The process of claim 10 in which the B blocks consist of dimethyl-butadiene units.
- 14. The process of claim 4 in which the dispersant is a diblock polymer comprising styrene and butadiene blocks having a number average molecular weight of 140,000 and a styrene content of about 40% by weight.
- 15. The process of claim 14 wherein the copolymer comprises 70 to 90% by weight of the polymerized styrene and 10 to 30% by weight of the polymerized butadiene.
- 16. The process of claim 15 wherein the copolymer comprises 75 to 85% by weight of the polymerized styrene and 15 to 25% by weight of the polymerized butadiene.
- 17. The process of claim 11 wherein the copolymer comprises 70 to 90% by weight of polymerized para-methylstyrene and 10 to 30% by weight of polymerized butadiene.
- 18. The process of claim 12 wherein the copolymer comprises 70 to 90% by weight of polymerized para-methylstyrene and 10 to 30% by weight of polymerized isoprene.
- 19. The process of claim 13 wherein the copolymer comprises 70 to 90% by weight of the polymerized para-methylstyrene and 10 to 30% by weight of the polymerized dimethyl-butadiene.
- 20. The process of claim 4 wherein the dispersing medium is hexane.
- 21. The process of claim 4 which is conducted at a temperature of between 30 and about 100.degree. C.
- 22. The process of claim 21 which is conducted in the presence of an anionic catalyst, with the catalyst concentration being 10.sup.-1 to 10.sup.-4 moles/100 g of the monomers.
- 23. The process of claim 22 wherein the anionic catalyst is butyl-lithium, sec-butyl-lithium or t-butyl lithium.
- 24. The process of claim 23 wherein the dispersant is used in the amount of 0.1 to 5.0% by weight of the monomers.
- 25. The process of claim 24 wherein the block copolymer has 5-10 alternating blocks of (A) units and (B) units and is terminated by (A) units.
- 26. The process of claim 14 which is conducted in hexane as the dispersing medium, and in the presence of 0.5 ml of 1.4 M sec-butyl lithium to prepare a linear block copolymer containing polymerized styrene blocks (A) and polymerized butadiene blocks (B) to produce five block linear polymer having a number average molecular weight of about 150,000.
Parent Case Info
This is a divisional of application Ser. No. 901,506, filed on Aug. 28, 1986, now abandoned.
US Referenced Citations (5)
Foreign Referenced Citations (1)
Number |
Date |
Country |
46-3990 |
Jan 1971 |
JPX |
Divisions (1)
|
Number |
Date |
Country |
Parent |
901506 |
Aug 1986 |
|