Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Reexamination Certificate
2002-01-15
2003-07-22
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
C502S164000, C502S161000
Reexamination Certificate
active
06596840
ABSTRACT:
The present invention provides a melt transesterification process for the production of polycarbonates.
The production of aromatic polycarbonates using the melt transesterification process is known from the literature and is described, for example, in
Encyclopedia of Polymer Science
, volume 10 (1969),
Chemistry & Physics of Polycarbonates, Polymer Reviews
, H. Schnell, volume 9, John Wiley & Sons Inc. (1964) and, on the basis of DE 1 031 512, described in various patents. Pat. EP 360 578demonstrates that the end groups of a polycarbonate which has been produced by melt transesterification may be exchanged by addition of a chain terminator. It has, however, been found that only a proportion of the introduced quantity of chain terminator actually remains as an end group in the polycarbonate. Since the end groups have a substantial influence upon mechanical properties, in particular of grades of PC having an elevated chain terminator content, in particular low molecular weight and branched grades of PC, it is desirable to ensure that the phenol end groups are replaced as completely as possible by other more suitable phenols. Moreover, when the phenol arising during polycondensation is removed from the process by distillation, it is contaminated by the chain terminator if this latter substance has not been completely incorporated. It is accordingly desirable to ensure maximally complete incorporation not only with regard to an elevated reaction yield, but also with regard to reuse of the phenol removed by distillation.
The object accordingly arose of providing a melt transesterification process which permits the production of polycarbonates, some of the end groups of which consist of phenols other than phenol, wherein as much of the introduced chain terminator as possible should be incorporated.
This object is achieved by a process for the production of polycarbonates from bisphenols, preferably from bisphenol A, and carbonic acid diesters, in the presence of a phenol suitable as a chain terminator, wherein the phenol used as chain terminator may be introduced in free form or as a compound transesterifiable under the conditions of synthesis, which process is characterised in that phosphonium salts, optionally combined with other catalysts, in particular sodium ions, are used as the catalyst.
For the purposes of the process according to the invention, phosphonium salts are those of the formula (I),
wherein R
1-4
may be identical or different C
1
-C
18
alkyls, C
6
-C
14
aryls, C
7
-C
12
aralkyls or C
5
-C
6
cycloalkyls, preferably methyl or C
6
-C
14
aryls, particularly preferably methyl or phenyl, and X
−
may be an anion such as sulfate, hydrogen sulfate, hydrogen carbonate, carbonate, acetate, hydridoborate, hydrogen phosphate, a halide, preferably fluoride, chloride or bromide, an alkoxide of the formula OR, wherein R is C
6
-C
14
aryl, C
7
-C
12
aralkyl, preferably phenyl. Preferred catalysts are
tetraphenylphosphonium fluoride
tetraphenylphosphonium tetraphenylhydridoborate,
particularly preferably tetraphenylphosphonium phenolate.
Sodium ion catalysts which may be used are hydroxides, hydrogen carbonates, carbonates, alkoxides, acetates, hydridoborates, hydrogen phosphates and hydrides, preferably hydroxides and alkoxides, particularly preferably the sodium salts of the phenols and bisphenols as mentioned in relation to the bisphenols and chain terminators and the sodium salt of phenol itself, very particularly preferably the sodium salt of 2,2-bis-(4-hydroxyphenyl)propane.
Alkylphenols suitable as chain terminators for the purposes of the process according to the invention are those of the formula (II),
wherein R, R′ and R″ may mutually independently comprise H, optionally branched C
1
-C
34
alkyl/cycloalkyl, C
7
-C
34
alkaryl or C
6
-C
34
aryl, for example
o-n-butylphenol, m-n-butylphenol, p-n-butylphenol,
o-isobutylphenol, m-isobutylphenol, p-isobutylphenol,
o-tert.-butylphenol, m-tert.-butylphenol, p-tert.-butylphenol,
o-n-pentylphenol, m-n-pentylphenol, p-n-pentylphenol,
o-n-hexylphenol, m-n-hexylphenol, p-n-hexylphenol,
o-cyclohexylphenol, m-cyclohexylphenol, p-cyclohexylphenol,
o-phenylphenol, m-phenylphenol, p-phenylphenol,
o-isooctylphenol, m-isooctylphenol, p-isooctylphenol,
o-n-nonylphenol, m-n-nonylphenol, p-n-nonylphenol,
o-cumylphenol, m-cumylphenol, p-cumylphenol,
o-naphthylphenol, m-naphthylphenol, p-naphthylphenol,
2,5-di-tert.-butylphenol, 2,4-di.-tert.-butylphenol, 3,5-di-tert.-butylphenol,
2,5-dicumylphenol, 3,5-dicumylphenol,
4-phenoxyphenol, 2-phenoxyphenol, 3-phenoxyphenol,
3-pentadecylphenol, 2-pentadecylphenol, 4-pentadecylphenol,
2-phenylphenol, 3-phenylphenol, 4-phenylphenol,
tritylphenol, 3-triphenylmethylphenol, 2-triphenylmethylphenol,
as well as benzotriazole derivatives of the general formula (III)
with the above-stated meaning of R, R′ and R″ for R
a
-R
f
and chromane compounds such as
preferably low-boiling phenols such as tritylphenol, cumylphenol, phenoxyphenol, pentadecylphenol or chromanes,
or also as compounds transesterifiable under the conditions of synthesis, such as for example carbonates, oxalates, o-carboxylic acid esters or the like, with preferred compounds being free phenols or carbonic acid diesters of the formula (IV)
and the formula (V),
wherein R, R′ and R″ correspond to those of the formula (II). Phenols or transesterifiable substances may be added to the synthesis individually or as a mixture. Preferred mixtures are those including diphenyl carbonate. Using the process according to the invention, it is possible to add the phenol or phenol-bearing compound at any time during the reaction, preferably at the beginning of the reaction, and addition may be divided into two or more portions. The entire proportion of carbonic acid esters is 100-130 mol %, preferably 103-120 mol %, relative to the dihydroxy compound.
When producing polycarbonates using the process according to the invention, the chain terminator is preferably added as an alkylphenol at a rate of 0.4-17 mol %, preferably of 1.3-8.6 mol % (relative to the dihydroxy compound). This addition may be made not only before the reaction but also entirely or in part during the reaction.
Dihydroxy compounds for the purposes of the process according to the invention are those of the formula (VI)
HO—Z—OH (VI)
in which Z is an aromatic residue having 6 to 30 C atoms, which residue may contain one or more aromatic rings, may be substituted and may contain aliphatic or cycloaliphatic residues or alkylaryls or heteroatoms as linking members.
Examples of dihydroxy compounds of the formula (VI) are
hydroquinone,
resorcinol,
dihydroxydiphenyls,
bis-(hydroxyphenyl)alkanes,
bis-(hydroxyphenyl)cycloalkanes,
bis-(hydroxyphenyl) sulfides,
bis-(hydroxyphenyl) ethers,
bis-(hydroxyphenyl) ketones,
bis-(hydroxyphenyl) sulfones,
bis-(hydroxyphenyl) sulfoxides,
&agr;,&agr;′-bis-(hydroxyphenyl)diisopropylbenzenes
together with the ring-alkylated and ring-halogenated compounds thereof.
These and further suitable other diphenols are described, for example, in U.S. Pat. Nos. 3 028 365, 3 148 172, 3 275 601, 2 991 273, 3 271 367, 3 062 781, 2 970 131 and 2 999 846, in DE-OS 1 570 703, DE-OS 2 063 050, DE-OS 2 063 052, DE-OS 2 211 0956, French patent 1 561 518 and in the monograph by H. Schnell,
Chemistry & Physics of Polycarbonates
, Interscience Publishers, New York 1964.
Preferred diphenols are, for example:
4,4′-dihydroxydiphenyl,
2,2-bis-(4-hydroxyphenyl)propane,
2,4-bis-(4-hydroxyphenyl)-2-methylbutane,
1,1-bis-(4-hydroxyphenyl)cyclohexane,
1,1-bis-(4-hydroxyphenyl)-4-methylcyclohexane,
&agr;,&agr;′-bis-(4-hydroxyphenyl)-p-diisopropylbenzene,
&agr;,&agr;′-bis-(4-hydroxyphenyl)-m-diisopropylbenzene,
bis-(4-hydroxyphenyl) sulfone,
bis-(4-hydroxyphenyl)methane,
1,1-bis-(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane,
2,2-bis-(2,6-dimethyl-4-hydroxyphenyl)propane,
2,2-bis-(4-hydroxyphenyl)hexafluoropropane,
1,1-(4-hydroxyphenyl)-1-phenylethane,
bis-(4-hydroxyphenyl)diphenylmethane,
dihydroxydiphenyl ethe
Bunzel Lothar
Hucks Uwe
Kratschmer Silke
Bayer Aktiengesellschaft
Boykin Terressa M.
Gil Joseph C.
Preis Aron
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