Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Reexamination Certificate
2002-10-02
2004-05-11
Boykin, Terressa (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From phenol, phenol ether, or inorganic phenolate
C264S176100, C264S219000, C359S107000, C369S047360, C528S198000
Reexamination Certificate
active
06734278
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates, in general to processes for the production of carbonates, and more specifically, to a two-stage process for the production of polyester carbonates with aliphatic dicarboxylic acids, the polyester carbonates obtained thereby, methods for the production of extrudates and molded articles from these polyester carbonates and the extrudates and molded articles obtained thereby.
BACKGROUND OF THE INVENTION
The transesterification process is well known in the art for the incorporation of aromatic dicarboxylic acids and is described, for example, in U.S. Pat. No. 4,459,384. The incorporation of aliphatic dicarboxylic acids is described in JP-A 2000 248 057.
The production of polyester carbonates from difunctional, aliphatic carboxylic acids and dihydroxy compounds via the phase interface process is described, for example, in EP-A 433 716, U.S. Pat. No. 4,983,706 and U.S. Pat. No. 5,274,068. EP-A 433 716 teaches that although the known carboxylic acids for polyester carbonates can be incorporated in significant amounts, this is possible only by a complicated, pH-controlled procedure.
In addition, the polyester carbonates produced by the phase interface process contain amounts of anhydrides of the employed dicarboxylic acids and/or free acid that are too low, which is undesirable according to EP-A 926 177. It is therefore desirable to incorporate the dicarboxylic acids as completely as possible into the polyester carbonate so that as many ester bonds as possible, in addition to few acid or anhydride structures, are present in the product, as those adversely affect the stability of the polyester carbonate.
In contrast to the complicated phase interface process, polyester carbonates may be synthesized considerably more easily by the transesterification process. Although the polyester carbonates contain hardly any anhydride structures, as is disclosed in DE Application No. 10131127.3, these compounds normally exhibit a fairly pronounced intrinsic coloration, which seriously affects their suitability for most applications.
SUMMARY OF THE INVENTION
The present invention, therefore, provides a process for the production of a polyester carbonate that is obtained without the need for a constant, complicated pH control, but that has a good intrinsic color and small amounts of anhydride structures. This has surprisingly been achieved by combining transesterification and phase interface processes.
DETAILED DESCRIPTION OF THE INVENTION
The present invention will now be described for purposes of illustration and not limitation.
The present invention provides a process for the production of polyester carbonates, wherein condensation takes place in a first stage as a melt transesterification process to form oligomers, which are condensed in a second stage by the phase interface process to form the polymeric polyester carbonate.
As the melt transesterification process for the production of the oligocarbonates in the first stage of the process according to the present invention, there may in principle be used any melt transesterification process for the production of polycarbonate known in the art. Such processes are described, for example, in the following applications and issued patents: DE-A-1 031 512, U.S. Pat. No. 3,022,272, U.S. Pat. No. 5,340,905, U.S. Pat. No. 5,399,659, DE-A 4 312 390, U.S. Pat. No. 5,912,318, U.S. Pat. No. 5,932,683, U.S. Pat. No. 5,912,289, WO 00/26 276 and EP-A 620 240. A process for the production of oligocarbonates is likewise described in German application no. 1 01 14 808.9. Further details of the melt transesterification process in general may be found, for example, in Hermann Schnell, Chemistry and Physics of Polycarbonates, Polymer Reviews, Vol. 9, 1964, pp. 44 to 51.
As the phase interface process for the condensation of the oligomers to the polymer in the second stage of the process according to the present invention, there may in principle be used any phase interface process for the production of polycarbonate known in the art. Such processes are described, for example, in
Schnell, “Chemistry and Physics of Polycarbonates”, Polymer Reviews, Volume 9, Interscience Publishers, New York, London, Sydney 1964, pp. 33 ff.,
D. C. Prevorsek, B. T. Debona and Y. Kesten, Corporate Research Center, Allied Chemical Corporation, Morristown, N.J. 07960: “Synthesis of Poly(ester Carbonate) Copolymers” in Journal of Polymer Science, Polymer Chemistry Edition, Vol. 18, (1980), pp. 75 ff.,
D. Freitag, U. Grigo, P. R. Müller, N. Nouvertne', BAYER A G, “Polycarbonates” in Encyclopedia of Polymer Science and Engineering, Volume 1 1, Second Edition, 1988, pp. 651 ff., and finally
Dres, U. Grigo, K. Kircher and P. R. Müller “Polycarbonate” in Becker/Braun, Kunststoff-Handbuch, Vol. 3/1, Polycarbonate, Polyacetale, Polyester, Celluloseester, Carl Hanser Verlag Munich, Vienna 1992, pp. 118 ff. and 138 ff.
According to the process of the present invention, in the first stage, a mixture of dihydroxy compound and diaryl carbonate is heated in an inert gas atmosphere and under reduced pressure to a temperature of 200° C.-290° C., following which, the resultant hydroxyaryl component is distilled off. A dicarboxylic acid or dicarboxylic acid mixture is then added and the reaction mixture is heated in vacuo and condensed to form the oligomer. At each point, the pressure is selected in a way that the hydroxyaryl component can be distilled off without any problem. In the second stage, the resultant oligomer is condensed in a phase interface process to form the polyester carbonate. For this stage, the oligomer is dissolved in an inert solvent before the condensation with phosgene takes place in the presence of aqueous, alkaline solution. The reaction temperature is between 0° C. and 50° C. The organic solution is purified by a subsequent washing and the solvent is removed.
The polyester carbonate obtained according to the invention is light colored, i.e. it has a color index of <0.1.
The remaining definitions, parameters and explanations given above, or subsequently, as generally applicable or applicable in preferred ranges may also be combined arbitrarily with one another, i.e. between the respective ranges and preferred ranges. They apply as appropriate to the end products as well as to the starting products and intermediate products, and to processes as well as process stages.
Dicarboxylic acids suitable for the process according to the present invention are those of the formula (I)
HOOC—T—COOH (I)
wherein T represents a branched or linear, saturated or unsaturated alkyl, arylalkyl or cycloalkyl radical consisting of 4-38 carbon atoms.
Preferred are saturated, linear alkyl diacids with 6-40 carbon atoms, particularly preferably those with 12 to 36 carbon atoms. Among these classes of substances, fatty acids are especially suitable, particularly preferably hydrogenated, dimeric fatty acids.
Moreover, the dicarboxylic acids of formula (I) can be mixed with aliphatic, araliphatic or aromatic hydroxy carboxylic acids with 4 to 40 carbon atoms like e.g. salicylic acid oder p-hydroxybenzoic acid.
Instead of the diacids their precursor compounds like e.g. anhydrides, lactones or phenyl esters may be used, provided that the free acids are liberated in situ under the conditions of the oligomer formation.
Preferred dicarboxylic acids of the formula (I) or mixtures of such acids are: adipic acid, cis or trans-1,2-cyclohexanedicarboxylic acid, cis or trans-1,3-Cyclohexanedicarboxylic acid, cis or trans-1,4-Cyclohexanedicarboxylic acid, sebacic acid, &agr;,&ohgr;-dodecanedioic acid, &agr;,&ohgr;-octadecanoic acid, phthalic acid, isophthalic acid, terephthalic acid, hydrogenated dimeric fatty acids, such as for example Pripol 1009 from Uniqema.
Hydrogenated dimeric fatty acids are acids, which are produced by dimerization of non-saturated monobasic fatty acids with 16 to 22 carbon atoms and subsequent hydrogenation. The required fatty acids can be derived from animal or plant sources. Synthesis and properties are e.g. described in Encycl
Alewelt Wolfgang
Bruder Friedrich-Karl
Bunzel Lothar
Fischer Peter
Haese Wilfried
Bayer Aktiengesellschaft
Boykin Terressa
Franks James R.
Gil Joseph C.
Mrozinski John E.
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