Method of preparing polyestercarbonates

Details Method of preparing polyestercarbonates Method of preparing polyestercarbonates

2002-04-10

2003-07-29

Boykin, Terressa M. (Department: 1711)

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

Synthetic resins

From phenol, phenol ether, or inorganic phenolate

C528S196000, C528S271000, C528S272000, C568S716000, C568S717000, C568S722000, C568S723000, C568S724000, C568S749000, C568S750000

Reexamination Certificate

active

06600004

ABSTRACT:

BACKGROUND OF THE INVENTION
This invention relates to a method of preparing polyestercarbonates. More particularly the method relates to a method of preparing polyestercarbonates in which diacids rather than diesters are employed as starting materials and said diacids are incorporated into the polyestercarbonate backbone with a high level of efficiency.
Polyestercarbonates based on aliphatic diacids and aromatic bisphenols are known, commercially useful materials which are currently prepared under interfacial polymerization conditions comprising reaction of a mixture of a bisphenol such as bisphenol A (BPA) together with a dicarboxylic acid such as dodecandioic acid with phosgene in the presence of a solvent and an aqueous solution of an acid acceptor such as sodium hydroxide. “SP” polycarbonate which typifies such polyestercarbonates is a copolymer of BPA (~92 mole %) and dodecanedioic acid (DDDA) (~8 mole %) and is available from GE Plastics, Mt Vernon, Ind. Because the “SP” polycarbonate is prepared in the presence of a solvent, methylene chloride, the manufacture of “SP” polycarbonate currently requires a solvent removal. Solvent removal is typically carried out by introducing steam into a solution of the product polyestercarbonate, a process which can result in fusion of the isolated powder resin owing to the presence of solvent and the inherently lower glass transition temperatures of polyestercarbonates incorporating comonomer such as DDDA relative to the corresponding homopolycarbonates. Therefore only high molecular weight material can be manufactured this way.
An alternative route to polyestercarbonates using a melt process would be highly desirable to circumvent problems attending solvent removal and allow the manufacture of lower molecular weight polyestercarbonates having lower melt viscosities. However, utilizing the traditional melt polycarbonate approach utilizing diphenyl carbonate (DPC) as the carbonate source requires long reaction times and high temperatures to achieve high molecular weight. As an added drawback, less than 100% of the expensive DDDA is incorporated by this method. An alternate approach which circumvents this reduced reactivity of DDDA uses the diphenyl ester of DDDA in the melt polymerization. This approach, however, requires preparation of the diphenyl ester of the diacid and further escalates both the cost and complexity of the process. Thus, there exists a need for a new method which allows the efficient incorporation of diacid comonomers directly into polyestercarbonates without recourse to interfacial polymerization techniques and which demonstrate a higher level of efficiency than is observed using known melt polymerization techniques.
BRIEF SUMMARY OF THE INVENTION
The present invention provides a method for the preparation of polyestercarbonates, said method comprising preparing a mixture comprising at least one activated diaryl carbonate, at least one dihydroxy aromatic compound, at least one diacid, at least one melt polymerization catalyst and optionally one or more co-catalysts, and heating under melt polymerization conditions to afford a product polyestercarbonate.
The method further relates to the preparation of polycarbonate esters having a high level of polymer endcapping.
DETAILED DESCRIPTION OF THE INVENTION
The present invention may be understood more readily by reference to the following detailed description of preferred embodiments of the invention and the examples included therein. In the following specification and the claims which follow, reference will be made to a number of terms which shall be defined to have the following meanings:
The singular forms “a”, “an” and “the” include plural referents unless the context clearly dictates otherwise.
“Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not.
As used herein, the term “melt polycarbonate” refers to a polycarbonate made by the transesterification of a diaryl carbonate with a dihydroxy aromatic compound.
“BPA” is herein defined as bisphenol A or 2,2-bis(4-hydroxyphenyl)propane.
“Catalyst system” as used herein refers to the catalyst or catalysts that catalyze the transesterification of the bisphenol with the diaryl carbonate in the melt process.
“Catalytically effective amount” refers to the amount of the catalyst at which catalytic performance is exhibited.
As used herein the term “aliphatic radical” refers to a radical having a valence of at least one comprising a linear or branched array of atoms which is not cyclic. The array may include heteroatoms such as nitrogen, sulfur and oxygen or may be composed exclusively of carbon and hydrogen. Examples of aliphatic radicals include methyl, methylene, ethyl, ethylene, hexyl, hexamethylene and the like.
As used herein the term “aromatic radical” refers to a radical having a valence of at least one comprising at least one aromatic group. Examples of aromatic radicals include phenyl, pyridyl, furanyl, thienyl, naphthyl, phenylene, and biphenyl. The term includes groups containing both aromatic and aliphatic components, for example a benzyl group.
As used herein the term “cycloaliphatic radical” refers to a radical having a valance of at least one comprising an array of atoms which is cyclic but which is not aromatic. The array may include heteroatoms such as nitrogen, sulfur and oxygen or may be composed exclusively of carbon and hydrogen. Examples of cycloaliphatic radicals include cyclcopropyl, cyclopentyl cyclohexyl, tetrahydrofuranyl and the like.
As used herein the abbreviation “BMSC” stands for the activated diaryl carbonate bis(methyl salicyl) carbonate (CAS No. 82091-12-1).
The present invention provides a method for preparing polyestercarbonates by reacting under melt polymerization conditions at least one activated diaryl carbonate with at least one dihydroxy aromatic compound and at least one diacid in the presence of a catalytically effective amount of at least one melt polymerization catalyst and optionally one or more co-catalyst.
The activated diaryl carbonate used according to the method of the present invention is “activated” in the sense that it undergoes transesterification reaction under melt polymerization conditions with a dihydroxy aromatic compound at a rate faster than the rate of the corresponding reaction of diphenyl carbonate. Activated diaryl carbonates thus encompass diaryl carbonates substituted with one or more electronegative substitutents such as halogen, cyano, perhaloalky, nitro, acyl and the like. Examples of activated diaryl carbonates for use according to the method of the present invention include bis(2-acetylphenyl) carbonate, bis(4-acetylphenyl) carbonate, bis(2-pivaloylphenyl) carbonate, bis(4-pivaloylphenyl) carbonate, bis(2-cyanophenyl) carbonate, bis(4-cyanophenyl) carbonate, bis(2-chlorophenyl) carbonate, bis(4-chlorophenyl) carbonate, bis(2, 4-dichlorophenyl) carbonate, bis(2, 4, 6-trichlorophenyl) carbonate, bis(2-nitrophenyl) carbonate, bis(4-nitrophenyl) carbonate, bis(2-fluorophenyl) carbonate, bis(2, 4-difluorophenyl) carbonate, bis(2, 4, 6-trifluorophenyl) carbonate, bis(2-trifluoromethylphenyl) carbonate, bis(4-trifluoromethylphenyl) carbonate, bis(2-chloro-4-trifluoromethylphenyl) carbonate, and the like.
In one embodiment the activated diaryl carbonate used according to the method of the present invention has structure I
wherein R
1
and R
2
are independently C
1-C
20
alkyl radicals, C
4
-C
20
cycloalkyl radicals or C
4
-C
20
aromatic radicals, R
3
and R
4
are independently at each occurrence a halogen atom, cyano group, nitro group, C
1
-C
20
alkyl radical, C
4
-C
20
cycloalkyl radical, C
4
-C
20
aromatic radical, C
1
-C
20
alkoxy radical, C
4
-C
20
cycloalkoxy radical, C
4
-C
20
aryloxy radical, C
1
-C
20
alkylthio radical, C
4
-C
20
cycloalkylthio radical, C
4
-C
20
arylthio radical, C
1
-C
20
alkylsulfinyl radical,C
4
-C
20
cycloalkylsulfinyl radical, C
4
-C
20
arylsulfinyl radical, C
1
-

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