Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Reexamination Certificate
2002-06-26
2003-11-11
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
C528S198000, C528S271000, C528S272000
Reexamination Certificate
active
06646099
ABSTRACT:
FIELD OF THE INVENTION
The application relates to polyester carbonate and more particularly to a melt transesterification process for its manufacture.
SUMMARY OF THE INVENTION
A transesterification process for producing polyester is disclosed. In a first stage of the process there is heated, in an inert gas atmosphere, a first mixture containing at least one dihydroxy compound and at least one diaryl carbonate to form an oligocondensate. In a second stage there is added to the oligocondensate at least one dicarboxylic acid to form a second mixture. The second mixture is heated to a temperature not higher than 290° C. in the presence of a quaternary onium compound as catalyst to form polyester carbonate. Hydroxyaryl formed throughout the process is distilled-off under reduced pressure.
BACKGROUND OF THE INVENTION
The production of polyester carbonates from difunctional, aliphatic carboxylic acids and dihydroxy compounds via the interfacial 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. As is disclosed in EP-A 433 716, the known carboxylic acids for producing polyester carbonates can however be incorporated in significant amounts only by a complicated and expensive procedure in the interfacial process.
The incorporation of aromatic or aliphatic dicarboxylic acids via the so-called pyridine process is described in U.S. Pat. No. 3,169,121.
The transesterification process is well known 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 although here, as is generally the case, all monomers are added jointly at the start of the reaction and are heated and/or condensed in common.
JP-A 3 203 926 likewise describes a transesterification process for the incorporation of aliphatic dicarboxylic acids. The dicarboxylic acids are in this case reacted with aromatic dihydroxy compounds and dicarbonates, alkali metal or alkaline earth metal compounds being used as catalyst. Apart from the proportion of incorporated dicarboxylic acid, no further details are given concerning possible secondary reactions or the intrinsic color of the polymers that are obtained.
Polyester carbonates that are produced by the interfacial process have a good intrinsic color, but contain minor amounts of anhydrides of the employed dicarboxylic acids or even free acid, which is undesirable. This is described in EP-A 926 177. However, in principle the object is to incorporate the dicarboxylic acids as completely as possible into the polyester carbonate so that as many ester bonds as possible in addition to as few acidic or anhydride structures as possible are present in the product, since these impair the stability of the polyester carbonate.
In contrast to this, although polyester carbonates that have been synthesised by the transesterification process contain few anhydride structures, nevertheless they normally have a strong intrinsic coloration, which in turn has to be as low as possible for most applications.
The object therefore existed of producing a polyester carbonate that on the one hand contains as many ester bonds as possible in addition to as few acidic or anhydride structures as possible, but that nevertheless on the other hand has a good intrinsic color.
DETAILED DESCRIPTION OF THE INVENTION
This object was surprisingly achieved by the transesterification process according to the invention.
The present application accordingly provides a process for the production of polyester carbonates by transesterification of diaryl carbonates with dihydroxy compounds and dicarboxylic acids, characterised in that the condensation is carried out in the presence of quaternary onium compounds as catalysts, wherein the dicarboxylic acids are added only after the oligocondensation of the dihydroxy compounds and the temperature does not exceed 290° C.
Furthermore, the present application also provides the polyester carbonates per se that can be obtained by the process according to the invention.
According to the process of the invention, in a first stage a mixture of dihydroxy compound and diaryl carbonate is heated in an inert gas atmosphere and under reduced pressure for 30 to 300 minutes, preferably for 60 to 150 minutes, up to a temperature of 200 to 290° C., preferably 230 to 290° C., particularly preferably 250° to 280° C., and the hydroxyaryl component that is formed is distilled off. The dicarboxylic acid or dicarboxylic acid mixture is then added in a second stage and the reaction mixture is heated for between 60 and 200 minutes, preferably between 90 and 180 minutes, at a temperature of not higher than 290° C., and condensed to form the polyester carbonate. In each stage the pressure is chosen so that the hydroxyaryl component can be distilled off without any problem.
The polyester carbonate obtained according to the invention is light in color, i.e. it has a color number of <0.2, and contains particularly low amounts of free dicarboxylic acid or anhydride structures and therefore satisfies the formula
Q
=
x
+
[
10
(
5
y
+
4
z
)
]
2
x
<
1.3
where
Q: is a characteristic number
x: is the wt. % of the esterified acid in the polyester carbonate
y: is the wt. % of free COOH in the polyester carbonate
z: is the amount, in wt. % of anhydride structural units in the polyester carbonate
Suitable dicarboxylic acids for the process according to the invention are those of the formula (I)
HOOC—T—COOH (I)
where
T denotes a branched or linear, saturated or unsaturated alkyl, arylalkyl or cycloalkyl radical with 8 to 40 carbon atoms.
Saturated linear alkyl diacids with 8 to 40 carbon atoms are preferred, diacids with 12 to 36 carbon atoms being particularly preferred. Of these classes of substances fatty acids, particularly preferably hydrogenated dimeric fatty acids, are particularly suitable.
Examples of dicarboxylic acids of the formula (I) or mixtures of such fatty acids are:
sebacic acid,
dodecanedioic acid,
stearic acid,
palmitic acid,
hydrogenated dimeric fatty acid, such as for example Pripol 1009 from Uniqema.
Pripol 1009 from Uniqema is a mixture of hydrogenated dimeric fatty acids that according to details given by Uniqema has roughly the following composition:
Structure (in each case various isomers)
Uniqema Data
ca. 30%
Linear
ca. 50%
Cyclic
Bicyclic
ca. 15-20%
Aromatic
Aromatic bicyclic
Particularly preferred are dodecanedioic acid and Pripol 1009.
Most particularly preferred is Pripol 1009.
Both a dicarboxylic acid of the formula (I) as well as a plurality of dicarboxylic acids of the formula (I) may be used.
The employed dicarboxylic acids as well as also the other raw materials that are used should of course be as pure as possible. In the case of commercial products the purity often varies greatly however. In particular fatty acids or hydrogenated dimerised fatty acids may contain considerable amounts of byproducts that are formed in their production.
The dicarboxylic acids and dihydroxy compounds may be used in the process according to the invention in a molar ratio X:1 therebetween, where 0<X<10, preferably 0.01<X<1, particularly preferably 0.02<X<0.5 and most particularly preferably 0.08<X<0.2.
The general or preferred definitions of radicals, parameters and/or explanations given above or hereinafter may also be arbitrarily combined with one another, i.e. between the respective ranges and preferred ranges. The details apply as appropriate to the end products as well as to the precursors and intermediate products and for processes as well as process stages.
Suitable dihydroxy compounds for the process according to the invention are those of the formula (II)
HO—Ar—OH (II)
in which Ar is an aromatic radical with 6 to 30 C atoms, preferably with 6 to 25 C atoms, that may contain one or more aromatic nuclei, may be substituted, and may contain aliphatic or cycloaliphatic radicals or alkylaryl radicals or heteroatoms as bridge members.
Example of d
Alewelt Wolfgang
Bunzel Lothar
Kratschmer Silke
Wilms Renate
Bayer Aktiengesellschaft
Boykin Terressa M.
Gil Joseph C.
Preis Aron
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