Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
08CL06~48
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PROCESS
BACRG}~OUND OF THE INVENTION
Polycarbonates are well known as a tough, clear,
highly impact resistant thermoplastic resin. However
the polycarbonates are also possessed of a relatively
high melt viscosity. Therefore in order to prepare a
molded article from polycarbonate, relatively high
extrusion and molding temperatures are re~uired.
Various efforts throughout the years to reduce the melt
viscosity while also maintaining the deYired physical
properties of the polycarbonates have been attempted.
These methods include the use of plagticizers, the use
of aliphatic chain stoppers, reduction of molecular
weight, the preparation of bisphenols having long chain
lS aliphatic substituents and various polycarbonate
copolymers a~ well as blends of polycarbonate with
other polymers.
With respect to plasticizers, these are generally
u~ed with thermoplastics to achieve higher melt flow.
However usually accompanying the plastici2er
incorporation into polycarbonate compositions are
undesirable features such as embrittlement and fugitive
characteristics of the plasticizer.
Increased flow can be fairly readily obtained with
the use of aliphatic chain stopper~, however impact
resistance as measured by notched izod drops
significantly. Embirttlement may also be problem.
When utilizing a bisphenol having a lengthy
aliphatic chain thereon, increases in flow can be
observed. However theqe are usually accompanied by
substantial decreases in the desirable property of
impact strength.
Various processes have been utilized to prepare
polycarbonates with increased processability. When
08CL06~48
i3~
--2--
utilizing a copolyestercarbonate with an aliphatic
segment, processes such as the pyridine solvent process
of USP 3,169,121, have been utilized as well as
processes utilizing diacid halides in an interfacial
process sequence such as disclosed in USP, 4,238,596
and USP, 4,238,597. Mditionally, high molecular
weight aliphatic segments have been introduced into the
polycarbonate (by interfacial methods) utilizing
dicarboxylic endcapped polyisobutylene segments, see
Mark and Peters USP, 4,677,183 and USP 4,628,081.
Additionally a method of incorporating aliphatic
dicarboxylic acids into polycarbonate is disclosed in
Rochanowski, USP, 4,280,683 wherein in an interfacial
process the diacids are reacted together with a
dihydric phenol and a carbonate precursor such as
phosgene.
As disclosed in the companion case filed on the
same day and designated as 8CL-6819, the incorporation
of aliphatic alpha omega medium chain acids of from ten
to twenty carbon atoms produced copolyestercarbonates
of sharply increased processability as measured by melt
flow together with a property spectrum which was at
least substantially similar to the usual aromatic
polycarbonate. Therefore great intere~t has been
generated in successfully synthesizing the
copolyestercarbonate with the aliphatic ester segment.
Although a standard interfacial process utilizing the
chloride derivative of the saturated aliphatic alpha
omega diacids can be employed to prepare the
copolyestercarbonate the availability of the diacid
chloride starting materials i9 a problem. Aliphatic
diacid chlorides are commercially available only in
limited quantities and at a very high cost.
08CL06~48
3 ~ ~
Furthermore even high purity diacid chlorides contain
color contaminants which cause the final molded parts
to display an unattractively high yellowness index.
Therefore attention was focused on the readily
available, relatively inexpensive diacid star~ing
materials. The previously mentioned Rochanowski patent
was studied. The disclosure is directed to the usage
of various aliphatic dibasic acids as disclo~ed at
column 5, lines 13 through 22 in combination with a
dihydric phenol and a carbonate precursor such as
phosgene in an interfacial process. According to
Rochanowski at column 6, lines 24 to 31, the reaction
was carried out at a pH of between about 4.5 and 8,
preferably between about 5.5 and 6.5 until the dibasic
acid is consumed. The pH of the reaction is then
raised to a value of between ~ and 11.5 to complete the
reaction. The polyestercarbonate is isolated according
to standard techniques, see column 6, lines 24 through
30 of Kochanow~ki. Experiments which followed the
Kochanowski disclosure were conducted. 50% of adipic
acid present as a 10 mole ~ reactant was incorporated
within the polycarbonate backbone therefore providing a
5 mole % copolyestercarbonate. Additionally it has
been discovered that the preferred pH range disclosed
in Kochanowski does not bring about complete incor-
poration of diacids into copolyestercarbonates in a
reasonable time period. The procedure of Example 6,
see column 9, lines 1 to 13 of Xochanowski, discloses
the preparation of an azelate containing bisphenol-A
copolyestercarbonate. The azelaic acid reactant was
present at 25 mole percent of the bisphenol-A. The
most incorporation of azelate observed was 18 mole%
following the procedure of Example 6. It is therefore
08CL06~48
-4-
clear that in many situations, the dibasic acid cannot be
consumed in a practical sense. The raising of the pH
therefore should not occur according to the Kochanowski
disclosure. It should also be noted that Rochanowski
uses a very high excess of phosgene.
A new proce~s ha~ been discovered which can about
complete incorporation of aliphatic alpha amega diacids
into aromatic polycarbonate backbones thereby producing a
copolyestercarbonate having a predictable quantity of
e~ter. A new pH stepwise range is followed to obtain
copolye~tercarbonate wherein there is e sentially no
detectable unreacted dicarboxylic acid which contam-
inates the waste product stream or the resultant polymer.
The excess of phosgene employed in Rochanow~ki can be
sub~tantially reduced.
SUMMARY OF T~E INVENTION
In accordance with the invention there is a
process for preparing a copolyestercarbonate which
comprises reacting interfacially a dihydric phenol, a
carbonate precursor and an aliphatic alpha omega
dicarboxylic acid having from 9 to about 20 carbon atoms,
wherein the ~aid diacid is from about 2 to about 20 mole
percent based on the dihydric phenol reactant content and
wherein the pH i9 from about 8 to about 9 for about 70 to
about 95% of the carbonate precursor addition time and
is then raised to a pH from about 10 to 12 for the
remainder of the carbonate precursor addition time.
DETAILED DESCRIPTION OF T~E INVENTION
The copolyestercarbonates of this invention are
prepared utilizing the standard dihydric phenol and
carbonate precursor. The ususal dihydric phenols usef~1
in preparation of aromatic polycarbonates are also
available here. Examples of these dihydric phenols are:
08CL06~3~8
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--5--
(R)n (R~nl
HO ~ (~b ~ OH
wherein
R is independently selected from halogen,
monovalent hydrocarbon, and monovalent hydrocarbonoxy
radicals;
R1 is independently selected from halogen,
monovalent hydrocarbon, and monovalent hydrocarbonoxy
radicals;
W is selected from divalent hydrocarbon
O O O
radicals, -S-, -S-S-, -O-, -S-, -~-, and -
~
o
n and n1 are independently selected from integers
having a value of from 0 to 4 inclusive; and
b is either zero or one.
The monovalent hydrocarbon radicals represented by
R and R1 include the alkyl, cycloalkyl, aryl, aralkyl
and alkaryl radicals. The preferred alkyl radicals arethose containing from 1 to about 12 carbon atomq. The
preferred cycloalkyl radicals are those containing from
4 to about 8 ring carbon atoms. The preferred aryl
radicals are those containing from 6 to 12 ring carbon
atoms, i.e., phenyl, naphthyl, and biphenyl. The
preferred alkaryl and aralkyl radicals are those
containing from 7 to about 14 carbon atoms.
The preferred halogen radicals represented by R and
R are chlorine and bromine.
The divalent hydrocarbon radicals represented by w
include the alkylene, alkylidene, cycloalkylene and
cycloalkylidene radicals. The preferred alkylene
radicals are those containing from 2 to about 30 carbon
atoms. The preferred alkylidene radicals are those
containing from 1 to about 30 carbon atoms.
08CL06~48
6~
The preferred cycloalkylene and cycloalkylidene
radicals are those containin~ from 6 to about 16 ring
carbon atoms.
The monovalent hydrocarbonoxy radicals represented
by R and R1 may be represented by the formula - oR2
wherein R2 is a monovalent hydrocarbon radical of the
type described hereinafore. Preferred monovalent
hydrocarbonoxy radicals are the alkoxy and aryloxy
radicals.
Some illustrative non-limiting examples of the
dihydric phenols falling within the scope of the Formula
include:
2,2-bis~4-hydroxyphenyl)propane (bisphenol-A);
2,2-bi~3,5-dibromo-4-hydroxyphenyl)propane;
2,2-bis~3,5-dimethyl-4-hydroxyphenyl)propane;
1,1-bis(4-hydroxyphenyl)cyclohexane;
1,1-bls~3,5-dlmethyl-4-hydroxyphenyl)cyclohexane;
1,1-bis~4-hydroxyphenyl)decane7
1,4-bls~4-hydroxyphenyl)propanes
1,1-bl~4-hydroxyphenyl)cyclododecanes
1,1-bis~3,5-dimethyl-4-hydroxyphenyl)cyclodcdecane;
4,4 -dlhydroxydlphenyl ether;
4,4 -thiodlphenol;
4,4 -dihydroxy-3,3 -dichlorodiphenyl ether; and
4,4 -dihydroxy-2,5-dihydroxydiphenyl ether.
Other u~eful dihydric phenols which are also
~ultable for use in the preparation of the above
polycarbonates are dlsclo~ed in U.S. Patent Nos.
2,999,835; 3,028,365; 3,334,154; and 4,131,575, all of
which are incorporated herein by reference.
08CL06~48
~ ~ 5~
The carbonate precursor utilized in the invention
can be any of the standard carbonate precursors used in
interfacial reaction such as phosgene, and the like.
When using the interfacial proce~s it is also standard
practice to use a catalyst system well known in the
synthesis of polycarbonates and copolyestercarbonates.
A typical catalyst system is that of an amine system
such as tertiaryamine, amidine or guanidine.
Tertiaryamines are generally employed in such reactions.
Trialkylmine~ such as triethylamine are generally
preferred.
A chain terminating agent to control the molecular
weight of the polymer is usually present. Generally a
monofunctional agent such as a carboxylic or phenol is
lS used. Phenols are preferred. Example of such phenols
include phenol, paratertiary butyl phenol, isoctyl-
phenol, isononyl phenol, chromanyl compounds such as
Chroman I and cumyl compounds such as paracumyl phenol.
Quantitie~ of chain terminating agents can range from
about 0.5 to about 7 mole percent based on the dihydric
phenol. The monomer which supplies the aliphatic ester
units in the copolyestercarbonate is an aliphatic alpha
omega dicarboxylic acid from 9 to about 20 carbon atoms.
The aliphatic system i~ normal, branched or cyclic.
Example~ of the ~ystem reactants include sebacic acid,
dodecanedioic acid and variou~ branched alkylene
groupings. The normal aliphatic alpha omega
dicarboxylic acids are preferred, generally from 9 to
about 14 carbon atoms, inclusive. Saturated diacids are
preferred. Dodecanedioic acid and sebacic acids are
most preferred.
08CL06~48
~ ~ ,r, ~ 9 ~
-8-
The stepwise pH range is critical to the process.
Generally, a pH range of about 8 to 8.5 is maintained
during the first 70-95% of the phosgenation. Preferably
75-85%. Following this period, the p~ is raised to a
level of about 10.0 to 12 preferably 10.2 to 11.2
wherein the remainder of the phosgenation is carried
out. Generally an excess of phosgene is utilized to
ensure as complete a reaction as pos~ible. This excegs
is generally no more than about 30% of that necessary on
a molar basis to provide complete reaction.
Amine catalyst with a range of about 0.75 to about
3.0 mole percent based on the dihydric phenol content
can be employed.
NON INVENTION PREPARATIONS
A. At a pH of 10 to 11 throughout the
phosgenation, interfacial reactions of bisphenol-A,
phosgene and various dicarboxylic acids of differing
carbon chain length were attempted. The pH was
controlled with sodium hydroxide. The organic phase waq
methylene chloride. The~e reactions resulted in little
or no incorporation of the diacids as shown by NMR. The
diacids attempted to be incorporated within the
polycarbonate backbone were adipic, pimelic, suberic,
azelaic, sebacic, and dodecanedioic.
Example 6 of Kochanowski patent was rerun utilizing
the same proportions and conditions as Kochanowski.
About 18 Mol ~ of diacid was incorporated, as observed
by 1% NMR.
08CL06848
_9~
EXAMPLE
Utilizing various dicarboxylic acids at a 10 mole~
reactant level and following the interfacial reaction
conditions described above for the invention the pH
profile of the phosgenation was adjusted by phosgenating
at a pH of 8 to 8.5 for 85~ of the phos~enation period
and then increasing the pH to 10-11 during the remainder
of the phosgenation. The total time period of
phosgenation was 30-35 minutes. The re~ults are shown
in the Table below. The percent incorporation is based
on lH NMR. The Tg of the resulting polymer was
measured .
TABLE I
15 Acid C % incorP. Tg(C)
Adipic 6 0 152
Pimelic 7 34 143
Suberic 8 57 139
Azelaic 9 99+ 135
Sebacic 10 100 131
Dodecanedioic 12 100 129
As shown by the results in the table, the shorter
chain aliphatic alpha cmega dicarboxylic acids were not
incorporated to a great extent, if at all. Rather the
first diacid which was incorporated to a substantial
extent was azelaic acid. Once sebacic acid was
utilized, the diacid was 100% incorporated.
08CLo6843
--10~ G'7 ~ ~
EXAMPLE 2
Utilizing dodecanedioic acid and sebacic acid, the
pH reliance of the interfacial reaction of the diacids
as well as the time dependence o~ the pH level and the
quantity of catalyst, were variables studied for the
effect of percent incorporation of acid into the copoly-
estercarbonate backbone. The dihydric phenol employed
was bi~phenol-A. Phosgene was the carbonate source.
The pH was controlled by sodium hydroxide. The organic
solvent was methylene chloride. Both the dodecanedioic
(DDDA) and sebacic (SA) acids were used at 10 mole
percent level, based on the bisphenol-A quantity. IV is
intrinsic viscosity as measured at 25C in methylene
chloride and reported as dl/g. Mole ~ TEA is mole
percent triethylamine based on bisphenol-A.
Below are the results:
TABLE II
Dlacid pH Profile mol%Unreacted IV
~time Period of) TEADlacid (~)
phosqenation)
DDDA 8 (28%); 11 (72%) 1.0 2.7 .53
DDDA 8 (56%); 11 (44%) 1.0 0.3 .53
DDDA 8 (84%); 11 (16%) 1.0 0 54
DDDA 8 llOO%);ll (end) 1.0 0 .56
SA 8 (28%); 11 (72%) 1.0 2.9 .53
SA 8 (56~); 11 (44%) 1.0 0.8 .55
SA 8 (84%); 11 (16~) 1.0 0 .52
As observed from the data in Table II, in
comparison with the non invention preparation data the
reaction i3 highly pH dependent. It is also dependent
08CL068 48
2~
upon the length of time that the phosgenation is held at
the respective p~'s. Even though the correct pH's are
utilized, there may be significant unreacted diacids
present which contaminate the waste stream if the proper
pH time period i8 not observed.
