Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Organic compound containing
Reexamination Certificate
2004-10-15
2008-09-30
Lorengo, Jerry (Department: 1793)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Organic compound containing
C502S150000, C502S157000, C502S171000
Reexamination Certificate
active
07429549
ABSTRACT:
Rubbery polymers made by anionic polymerization can be coupled with tin halides or silicon halides to improve the characteristics of the rubber for use in some applications, such as fire treads. In cases where the rubbery polymer was synthesized utilizing a polar modifier it is difficult to attain a high level of coupling. This invention is based upon the unexpected finding that coupling efficiency can be significantly improved by conducting the coupling reaction in the presence of a lithium salt of a saturated aliphatic alcohol, such as lithium t-amylate. This invention discloses a process for coupling a living rubbery polymer that comprises reacting the living rubbery polymer with coupling agent selected from the group consisting of tin halides and silicon halides in the presence of a lithium salt of a saturated aliphatic alcohol. The lithium salt of the saturated aliphatic alcohol can be added immediately prior to the coupling reaction or it can be present throughout the polymerization and coupling process. Lithium t-amylate reacts with water to form t-amyl alcohol during steam stripping. Since t-amyl alcohol forms an azeotrope with hexane, it co-distills with hexane and can contaminate recycle feed streams. This problem of recycle stream contamination can be solved by using metal salts of cyclic alcohols that do not co-distill with hexane or form compounds during steam stripping which co-distill with hexane. Thus, the use of metal salts of cyclic alcohols is preferred for this reason and because they are considered to be environmentally safe.
REFERENCES:
patent: 4843120 (1989-06-01), Halasa et al.
patent: 5047483 (1991-09-01), Halasa et al.
patent: 5061765 (1991-10-01), Hsu et al.
patent: 5096973 (1992-03-01), Herrmann et al.
patent: 5137998 (1992-08-01), Hsu et al.
patent: 5137999 (1992-08-01), Oxenrider et al.
patent: 5239009 (1993-08-01), Halasa et al.
patent: 5272220 (1993-12-01), Rodgers et al.
patent: 5405927 (1995-04-01), Hsu et al.
patent: 5486574 (1996-01-01), Himes et al.
patent: 5620939 (1997-04-01), Halasa et al.
patent: 5627237 (1997-05-01), Halasa et al.
patent: 5654384 (1997-08-01), Halasa et al.
patent: 5677402 (1997-10-01), Halasa et al.
patent: 5700888 (1997-12-01), Hall
patent: 6140434 (2000-10-01), Halasa et al.
patent: 6353056 (2002-03-01), Knoll et al.
patent: 6583244 (2003-06-01), Jasiunas et al.
Halasa Adel Farhan
Hsu Wen-Liang
Lorengo Jerry
McDonough James E
Rockhill Alvin T.
The Goodyear Tire & Rubber Company
LandOfFree
Process for improved coupling of rubbery polymers does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for improved coupling of rubbery polymers, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for improved coupling of rubbery polymers will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3979475