Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
1999-07-02
2001-10-02
Short, Patricia A. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S437000
Reexamination Certificate
active
06297330
ABSTRACT:
FIELD OF THE INVENTION
This invention concerns a process for polymerizing cyclic oligomers in the presence of one or more linear polymers.
TECHNICAL BACKGROUND OF THE INVENTION
U.S. Pat. No. 5,648,454 (to GE) discloses synthesis of co-polyesters from co-cyclic compositions. This patent does not disclose polymerization in the presence of linear polymer.
EP 0 655 476 A1 (to GE) discloses polymerization of polyester cyclic oligomers specifying that the cyclic oligomers be free of linear polyester at the beginning of polymerization.
Modification of a premanufactured linear polyester by copolymerization with a polyester cyclic oligomer of different chemical composition with the intent of preparing polyesters of lower ultimate crystallinity is described in Cook, T. D.; Evans, T. L.; McAlea, K. P.; Pearce, E. J., U.S. Pat. No. 5,300,590 (1994) to GE.
JP 47-6425 (to Nippon Ester) discloses a means of post-polymerization molecular weight enhancement of linear polyester by adding cyclic oligomer to a melt of linear polyester. In this process, the linear polyester is made by conventional means and the cyclic simply provides on-line molecular weight enhancement. Our invention provides an entirely new method of making polyester.
There are many references on cyclic oligomer polymerization. However, none of these references teach the benefits of cyclic polymerization in the presence of linear polyesters which overcomes the high melting points of the cyclic oligomers, a difficulty often associated with cyclic oligomer polymerization.
SUMMARY OF THE INVENTION
This invention consists of polymerizing cyclic oligomers in the presence of one or more linear polymers which may be recycled from the product stream. The polymer product of this process may be a homopolymer or a co-polymer, depending on whether the chemical composition of the cyclic oligomer is the same as that of the linear polymer. Homopolymers or copolymers produced include those selected from the group consisting of polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyethylene naphthenate, polyethylene isophthalate and sulfonated polyethylene isophthalate, polyalkylene or sulfonated polyalkylene terephthalate, polyalkylene or sulfonated polyalkylene naphthenate, polyalkylene and sulfonated polyalkylene isophthalate.
This process provides rapid on-line polymerization or polymer modification at atmospheric pressure.
This invention overcomes the high melting points of the cyclic oligomers, a difficulty normally associated with cyclic oligomer polymerization. The process may be run either with or without a recycle loop, and is optionally conducted in the presence of a catalyst. For example, cyclic oligo(ethylene terephthalate) trimer melts at 321° C. (see J. Brandrup and E. H. Immergut, eds., Polymer Handbook, 3rd Edn., Wiley-Interscience, New York, 1989, page IV/50) which greatly exceeds the thermal stability of its linear polymer, poly(ethylene terephthalate). The use of ring-opening polymerization in the presence of the linear polymer as described herein facilitates the dissolution of the cyclic oligomer and subsequent reaction at temperatures such as 270-285° C. at which the polymer is thermally stable.
Specifically disclosed is a process for producing polymers including polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyethylene naphthenate, polyethylene isophthalate and sulfonated polyethylene isophthalate, polyalkylene or sulfonated polyalkylene terephthalate, polyalkylene or sulfonated polyalkylene naphthenate, polyalkylene and sulfonated polyalkylene isophthalate from cyclic oligomers selected from the group consisting of cyclic forms of polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyethylene naphthenate, polyethylene isophthalate and sulfonated polyethylene isophthalate.
The process as described can be done while the reacting mixture is in a solid-state, melt, slurry, suspension and/or solution state.
REFERENCES:
patent: 3018272 (1962-01-01), Griffing
patent: 5281669 (1994-01-01), Kambour
patent: 5300590 (1994-04-01), Cook et al.
patent: 5648454 (1997-07-01), Brunelle
patent: 5663282 (1997-09-01), Todt
patent: 0 655 476 A1 (1995-05-01), None
patent: 47-6425 (1972-02-01), None
Burch, Jr. Robert Ray
Dembek Alexa Ann
Lustig Steven Raymond
Spinu Maria
E. I. Du Pont de Nemours and Company
Short Patricia A.
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