Synthesis of polycarbonates using Co2

Details Synthesis of polycarbonates using Co2 Synthesis of polycarbonates using Co2

1997-04-11

2001-09-11

Mosley-Boykin, Terressa (Department: 1711)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

From phenol, phenol ether, or inorganic phenolate

C528S198000

Reexamination Certificate

active

06288202

ABSTRACT:

FIELD OF THE INVENTION
The invention relates to a process of forming polycarbonates using carbon dioxide both as a reactant and a reaction medium.
BACKGROUND OF THE INVENTION
Polycarbonates represent a widely used class of materials which possess highly desirable physical properties relating to, for example, transparency, heat distortion resistance, toughness, and electrical resistance. These properties make the polycarbonates especially well suited for applications relating to, for example, molded products, extruded film, structural parts, tubing and piping, and prosthetic devices.
Polycarbonates generally encompass aliphatic and aromatic polycarbonates, with the aromatic polycarbonates being particularly desirable in commercial applications. Traditional methods for forming aliphatic polycarbonates have focused on the transesterification of diols with lower dialkyl carbonates, dioxolanones, or diphenyl carbonates in the presence of catalysts containing, for example, alkali metal, tin, and titanium compounds. Aliphatic polycarbonates have also been formed using zinc initiating species which copolymerize carbon dioxide and oxiranes.
Aromatic polycarbonates differ from aliphatic polycarbonates in that they typically possess a higher level of thermal stability. In general, these materials are synthesized by different methods. Typically, aromatic polycarbonates are prepared by reacting bisphenols with carbonic acid derivatives at high temperatures, e.g., by reacting a diphenol and a diphenyl carbonate. These reactions are usually carried out at low pressures (e.g., vacuum conditions) and high temperatures. Although these reactions may occur in the absence of organic solvents, the reactions are potentially disadvantageous in that complex apparatuses are often necessary, primarily due to the presence of a vacuum and the formation of a high viscosity of the melt polymer reaction product.
Solid state polymerization (“SSP”) techniques are significant in that they are primarily used to chain extend low molecular weight polycarbonates to form higher molecular weight polymers. In order to carry out an SSP, it is often necessary to crystallize the polycarbonates. The polycarbonates are typically exposed to organic solvents such as methylene chloride, chlorobenzene, or chloroform to induce crystallization. The use of such organic solvents may be disadvantageous in that it raises certain potential environmental risks.
It is therefore an object of the present invention to provide processes of forming polycarbonates which do not require organic solvents and are not carried out under vacuum or low pressure conditions.
SUMMARY OF THE INVENTION
To the above end and others, the present invention provides processes for forming polycarbonates. In one aspect, the process of the invention comprises providing a reaction mixture of at least one polycarbonate-forming monomer and carbon dioxide, and then reacting the polycarbonate-forming monomer and the carbon dioxide in the reaction mixture to form the polycarbonate. The monomer is preferably selected from the group consisting of diphenyl carbonate, bisphenol-A, dimethyl carbonate, bisphenol-A diphenyl carbonate, and bisphenol-A, dimethyl carbonate, substituted bisphenol-A monomers, and mixtures thereof. Preferably, the polycarbonate is an aromatic polycarbonate selected from the group consisting of bisphenol-A polycarbonates.
In a second aspect, the invention relates to a process of forming a polycarbonate having increased molecular weight. Specifically, the process comprises providing a reaction mixture comprising at least one polycarbonate-forming oligomer and carbon dioxide, and then reacting the oligomer and the carbon dioxide to form a polycarbonate having a weight average molecular weight ranging from about 2,000 g/mol to about 500,000 g/mol.
In a third aspect, the invention relates to a process for forming crystalline polycarbonate. The process comprises providing a reaction mixture comprising uncrystallized polycarbonate and carbon dioxide, and then treating the uncrystallized polycarbonate with carbon dioxide to form the crystalline polycarbonate. The crystalline polycarbonate is preferably an aromatic polycarbonate present in a structure selected from the group consisting of granules, chips, thin films, and mixtures thereof. In this instance, the process may further comprise the step of extruding the aromatic polycarbonate manufactured or crystallized in CO
2
into an article of manufacture.
In a fourth aspect, the invention relates to a reaction mixture which comprises at least one monomer and carbon dioxide, wherein the monomer is capable of reacting with the carbon dioxide to form a polycarbonate.


REFERENCES:
patent: 3294772 (1966-12-01), Cottle
patent: 3522228 (1970-07-01), Fukui et al.
patent: 3668139 (1972-06-01), Daniels et al.
patent: 3689462 (1972-09-01), Maximovich et al.
patent: 3891605 (1975-06-01), Larsen et al.
patent: 4238593 (1980-12-01), Duh
patent: 4452968 (1984-06-01), Bolon et al.
patent: 4748220 (1988-05-01), Hartmann et al.
patent: 4754017 (1988-06-01), Leitz et al.
patent: 4764323 (1988-08-01), Al-Ghatta
patent: 4791929 (1988-12-01), Jarrett et al.
patent: 4920203 (1990-04-01), Tang et al.
patent: 4990595 (1991-02-01), Traechkner et al.
patent: 5015724 (1991-05-01), Kawabe
patent: 5049647 (1991-09-01), Al-Ghatta
patent: 5073203 (1991-12-01), Al-Ghatta
patent: 5256764 (1993-10-01), Tang et al.
patent: 5312882 (1994-05-01), DeSimone et al.
patent: 5382623 (1995-01-01), DeSimone et al.
patent: 5412068 (1995-05-01), Tang et al.
patent: 5434239 (1995-07-01), Bhatia
patent: 5478910 (1995-12-01), Russell et al.
patent: 5506331 (1996-04-01), Nagao et al.
patent: 5625027 (1997-04-01), Kuze et al.
patent: 5698665 (1997-12-01), Odell
patent: 5710238 (1998-01-01), Sivaram et al.
patent: 3537455A1 (1987-04-01), None
patent: 0 300 981 A1 (1989-01-01), None
patent: 0356815 (1990-03-01), None
patent: 0356815 A3 (1990-03-01), None
patent: 0 222 714 B1 (1992-03-01), None
patent: 0 269 583 B1 (1993-06-01), None
patent: 1172713 (1967-05-01), None
patent: 3177407 (1991-08-01), None
patent: WO 90/07536 (1990-07-01), None
patent: WO 96/39456 (1996-12-01), None
E. Beckman et al.; Crystallization of Bisphenol a Polycarbonate Induced by Supercritical Carbon Dioxide,J. of Polymer Science: Part B: Polymer Physics25:1511-1517 (1987).
Garg et al, “Thermodynamics of Polymer Melts Swollen With Supercritical Gases”,Macromolecules, 1994, vol. 27, pp. 5643-5653.
Condo et al., “Glass Transitions of Polymers with Compressed Fluid Diluents: Type II and III Behavior”,Macromolecules, 1994, vol. 27, pp. 365-371.
Iyer, V.S., et al., “Solid-State polymerization of Poly(aryl carbonate)s: A Facile Route to High Molecular Weight Polycarbonates”,Macromolecules, 1993, vol. 26, pp. 1186-1187.
Radhakrishnan, S., et al., “Structure and Morphology of Polycarbonate Synthesized by Solid State Polycondensation”,Polymer, 1994, vol. 35, pp. 3789-3791.
Beckman, et al., “Copolymerization of 1,2-Epoxycyclohexane and Carbon Dioxide Using Carbon Dioxide as Both Reactant and Solvent”,Macromolecules, 1997, vol. 20, No. 3, pp. 368-372.
Shuichi Oi, et al., “Direct synthesis of polycarbonates from CO2, diols, and dihalides”,Macromolecular: Rapid Communications, Feb. 1994, vol. 15, No. 2, pp. 133-137.
DeSimone et al., Dispersion Polymerizations In Supercritical Carbon Dioxide, Science, 265:356-359 (Jul. 15, 1994).
H. Mark et al., Polyesters, The Encyclopedia of Polymer Science and Engineering, Eds., 2d ed., 12:1-60 (1985).
M. McHugh et al., Supercritical Fluid Chromatography Analysis Of Polystyrene, Excerpts from Supercritical Fluid Extraction, EDS., pp. 147-159 (1986).
Shaffer et al., Chain Polymerizations In Inert Near- and Supercritical Fluids, TRIP 3, No. 5:146-153, (May 1995).
Varadarajan, Free Radical Polymerization In Supercritical Fluid Solvents, Doctoral Thesis Digest, pp. 2-34, Nov. 29, 1990.
Scholsky, Supercritical Polymerication Reactions, pp. 685-686.
V. Krukonis et al., Supercritical Fluid Chromatography Analysis of Polystyrene, Polymer Fractionation, pp. 146-147, 156-1

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