Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Reexamination Certificate
1999-12-14
2001-10-23
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
Reexamination Certificate
active
06307006
ABSTRACT:
The present invention relates to a process for producing branched polycarbonates, by the melt transesterification of diphenols, diaryl carbonates and branching agents, optionally with the use of catalysts, at temperatures between 80 and 400° C. and at pressures between 1 atm. and 0.01 mbar, which is characterised in that tri- to hexahydric aliphatic alcohols of general formula (I)
are used as branching agents,
wherein
R′ is a single bond, a linear C
1
-C
36
alkylene or a branched C
3
-C
36
alkylene, preferably a linear alkylene comprising 1 to 18 C atoms,
wherein
R and R″ are the same or different, and denote H, a linear C
1
-C
30
alkyl, a branched C
3
-C
36
alkyl or R′″—OH, wherein R′″ is a linear C
1
-C
36
alkylene or a branched C
3
-C
36
alkylene, and
wherein
n is 2, 3, 4 or 5,
in amounts of 0.05 to 2 moles, preferably of 0.10 mole to 1.5 moles per 100 diphenol.
The preferred R and R″ radicals are H—, CH
3
— and C
2
H
5
—,
and the preferred R′″ radicals are CH
2
— and —CH
2
—CH
2
—.
In addition, suitable branching agents also include ethers, in fact monoethers and higher ethers also, which are formed by the self-condensation of alcohols of formula (I) with the separation of water.
The present invention thus relates to an extension of the process according to the invention, which is characterised in that instead of alcohols of formula (I) the ethers thereof, which are formed by self-condensation, are used in amounts of 0.05 moles to 2 moles, preferably of 0.1 mole to 1.5 moles, per 100 moles diphenol.
The polycarbonates produced by the process according to the invention are solvent-free and exhibit a light self-colour. They preferably have a low content of OH terminal groups of<1200 ppm, and are distinguished by their increased stability and intrinsic viscosity in the melt, and, compared with linear polycarbonate, by their reduced drip-off behaviour in the event of fire.
DE-A 15 70 533 describes the production of branched polycarbonates by the melt transesterification process. However, only phenolic compounds are employed as branching agents.
According to DE-A 25 00 092, 3,3-bis-(4-hydroxyaryl)-oxoindoles are used as branching agents for the production of branched polycarbonates.
EP-A 0 140 341 describes the production of a branched polycarbonate by way of the melt transesterification process, using triaryl esters of tricarboxylic acids, for example of trimellitic acid, as branching agents. In EP-A 0 708 130, 1,3,5-tris-(2-hydroxyethyl)-cyanuric acid (II)
is cited, amongst other compounds, as a branching agent in a special 2-step process (page 4, line 33 of EP-A 0 708 130), but is not used in the examples.
At the temperatures of melt transesterification, however, compound (II) should be transformed and decomposed, with the separation of
The same applies to 3,4,5-trihydroxyphenylethyl alcohol (III)
which is cited as a branching agent in EP-A 0 708 130 (page 4, line 41). Here also, the separation of
is conceivable.
In contrast, the aliphatic alcohols of formula (I) which are used according to the invention are thermally stable, and therefore do not decompose but are built up to form higher molecular weight ethers in all cases.
However, since aliphatic polyalcohols are not incorporated in a controlled manner in the phase boundary process used industrially, and since the process in organic solution which is termed the pyridine process is no longer used industrially, the process or melt transesterification according to the invention provides a practical process for incorporating aliphatic branching sites into thermoplastic, aromatic polycarbonates, with good reproducibility.
Thus the present invention also relates to thermoplastic, branched polycarbonates which can be obtained by the process according to the invention.
As mentioned above, these are distinguished by their high stability and intrinsic viscosity in the melt. At the same time, their drip-off behaviour in the event of fire is reduced compared with that of linear polycarbonate.
Examples of suitable alcohols (I) include pentaerythritol, glycerol, 1,2,3,6-hexanetetrol and 2,5-dimethyl-1,2,6-hexanetriol.
A suitable ether of (I) is dipentaerythritol, for example.
Diphenols which are suitable according to the invention are those of formula (IV)
HO—Z—OH (IV),
wherein
Z is a divalent radical, which preferably comprises 6 to 30 C atoms, which can be mononuclear or polynuclear, which may contain hetero atoms, which may be bridged or in ring form, and which may optionally contain inert substituents which do not change or do not react, either under the reaction conditions of the method according to the invention or under the known processing conditions for the polycarbonates obtainable according to the invention.
Examples which can be cited include hydroquinone, resorcinol, bis-(hydroxyphenyl)-alkanes, bis-(hydroxyphenyl)-cycloalkanes, bis-(hydroxyphenyl) sulphides, -ethers, -sulphoxides and -sulphones, and &agr;,&agr;-bis-(hydroxyphenyl)-diisopropylbenzenes, as well as compounds thereof which comprise alkylated and halogenated nuclei.
Examples of suitable diphenols are described in U.S. Pat. Nos. 3,028,365, 299,835, 3,062,781, 3,148,172 and 4,982,014, in DE-OS 1 570 703 and 2 063 050, and in the monograph by H. Schnell, “Chemistry and Physics of Polycarbonates”, Interscience Publishers, New York, 1964.
Preferred diphenols include
4,4′-dihydroxyphenyl,
2,2-bis-(4-hydroxyphenyl)-propane,
2,4-bis-(4-hydroxyphenyl)-2-methylbutane, 1,1-bis-(4-hydroxyphenyl)-cyclohexane,
&agr;,&agr;-bis-(4-hydroxyphenyl)-p-diisopropylbenzene,
&agr;,&agr;-bis-(4-hydroxyphenyl)-m-diisopropylbenzene,
2,2-bis-(3-methyl-4-hydroxyphenyl)-propane.
2,2-bis-(3-chloro-4-hydroxyphenyl)-propane,
bis-(3,5-dimethyl-4-hydroxyphenyl)-methane,
2,2-bis-(3,5-dimethyl-4-hydroxyphenyl)-propane,
bis-(3,5-dimethyl-4-hydroxyphenyl)-sulphone,
2,4-bis-(3,5-dimethyl-4-hydroxyphenyl)-2-methylbutane,
1-bis-(3,5-dimethyl-4-hydroxyphenyl)-cyclohexane,
&agr;,&agr;-bis-(3,5-dimethyl-4-hydroxyphenyl)-p-diisopropylbenzene,
1,1-bis-(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane,
1,1-bis-(4-hydroxyphenyl )-3-methylcyclohexane,
1, -bis-(4-hydroxyphenyl)-3,3-dimethylcyclohexane,
1,1-bis-(4-hydroxyphenyl)-4-methylcyclohexane,
2,2-bis-(3,5-dichloro-4-hydroxyphenyl)-propane,
2,2-bis-(3,5-dibromo-4-hydroxyphenyl)-propane,
1,1-bis-(4-hydroxyphenyl)-1-phenyl-ethane,
2,2-bis-(3,5-dimethyl-4-hydroxyphenyl)-2-phenyl-ethane,
2,2-bis-(4-hydroxyphenyl)-2,2-diphenyl-ethane,
9,9-bis-(4-hydroxyphenyl)-fluorene,
9,9-bis-(3,5-dimethyl-4-hydroxyphenyl)-fluorene.
Examples of particularly preferred diphenols include
9,9-bis-(4-hydroxyphenyl)-propane,
2,2-bis-(3,5-dimethyl-4-hydroxyphenyl)-propane,
1,1-bis-(4-hydroxyphenyl)-cyclohexane,
1,1-bis-(4-hydroxyphenyl)-1-phenyl-ethane,
1,1-bis-(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane,
1,1-bis-(4-hydroxyphenyl)-3-methylcyclohexane,
1,1-bis-(4-hydroxyphenyl)-4-methyl-cyclohexane.
9,9-bis-(3,5-dimethyl-4-hydroxyphenyl)-fluorene.
Most preferred diphenols include
2,2-bis-(4-hydroxyphenyl)-propane,
1,1-bis-(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, and
1,1-bis-(4-hydroxy-phenyl)-1-phenyl-ethane.
Any mixtures of the aforementioned diphenols can also be used.
Carboxylic acid esters in the sense of the present invention are di-C
6
-C
14
-aryl esters, preferably the diesters of phenol or alkyl-substituted phenols, namely diphenyl carbonate or dicresyl carbonate.
The carboxylic acid diesters are used in an amount of 1.01 to 1.30 moles, preferably 1.02 to 1.15 moles, with respect to 1 mole of bisphenol.
The diphenols, carboxylic acid diesters and branching agents are used in as pure a form as possible; this is self-evident to one skilled in the art. Pure diphenols and pure carboxylic acid esters are obtained in the known manner by recrystallisation, as is known to one skilled in the art. Washing or distillation are other possible ways of purifying the diphenols and carboxylic acid esters.
The catalysts which are preferably used are the ammonium and phosphonium salts which are known from th
Bunzel Lothar
Hucks Uwe
Konig Annett
Bayer Aktiengesellschaft
Boykin Terressa M.
Gil Joseph C.
Preis Aron
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