Note: Descriptions are shown in the official language in which they were submitted.
~57185 8CL-3451
This invention is directed to a plasticized poly-
carbonate composition comprising an admixture of a high
molecular weight aromatic polycarbonate and a particular
organotin plasticizer.
BACKGROUND OF THE INVENTION
Aromatic polycarbonates are excellent molding materials
as products made therefrom having high impact strength,
toughness, high transparency, wide temperature limits (high
impact resistance below -60C and a UL thermal endurance
rating of 115C with impact), good dimensional stability,
high creep resistance and electrical properties which
qualify it as sole support for current carrying parts.
Polycarbonates are, however, very difficult to
fabricate from melts since such melts have exceptionally
high viscosities. Attempts to overcome this difficulty
in polycarbonates employing materials known to reduce the
viscosity of other resins have very generally been un-
successful. Many standard viscosity control agents appear
to have little or no effect on the viscosity of polycar-
bonate. Other compounds known to lower the viscosity of
resins cause degradation of polycarbonate resins. Some
compounds, conventionally employed to improve the work-
ability of polymers, produce an embrittling effect when
they are employed with polycarbonates which are subjected
to elevated molding temperatures. Still other materials,
while satisfactory stiffness modifying agents for other
plastics, are too volatile to be incorporated with poly-
carbonates since polycarbonates have much higher melting
points than many other thermoplastics.
DESCRIPTION OF THE INVENTION
It has been discovered that, by admixing a plasticizing
amount of a particular organic plasticizer with a halogen-
-- 1 -- ~
8CL-3451
~1~;
free, high molecular weight aromatic polycarbonate, the
resultant polycarbonate composition has reduced melt viscosity
and does not become brittle or degraded upon molding, thus
retaining its characteristic high impact strength.
In the practice of this invention, the organotin plasti-
cizers that can be employed are also halogen-free and are
represented by the following formulae:
I. l2 II. R5-Sn-R~
Rl-7n-R3
R4
B III.IR~ IV.
R2-Sn- I n-R2 R2-Sn-,~-Sn~R2
R2 R2 ~3 R3
V -IRl ~ VI. r Rl o ~ 1
_ -7n-O- - . I Sn-O-~-R7-C-O
R2 n L ~1 ~n
where Rl and R2 can independently be Cl to C20 alkyl, cyclo-
alkyl of 4 to 14 carbon atoms, alkenyl of 2 to 20 carbon
atoms, aryl, and substituted aryl of 6 to 14 carbon atoms
wherein the substituents on said substituted aryl can be
alkoxy of 1 to 20 carbon atoms, alkaryl of 7 to 36 carbon
atoms, and aralkyl of 7 to 36 carbon atoms; R3 and R4 can
independently be Cl and C20 alkyl, cycloalkyl of 4 to 14
carbon atoms, alkoxy of 1 to 20 carbon atoms, cycloalkoxy
of 4 to 14 carbon atoms, aryloxy, and substituted aryloxy
of 6 to 14 carbon atoms wherein the substituents on said
substituted aryloxy can be alkyl of 1 to 20 carbon atoms,
acyloxy of 1 to 30 carbon atoms including aliphatic,
cycloaliphatic, aromatic and substituted aromatic radicals
wherein the substituents on said substituted aromatic
radicals can be alkyl of 1 to 20 carbon atoms; R5 and R6
8CL-3451
7i~8S
can independently be acyloxy radicals of 1 to 30 carbon
atoms including aliphatic, cycloaliphatic, aromatic and
substituted aromatic radicals wherein the substituents on
said substituted aromatic radicals can be an alkyl of 1
to 20 carbon atoms; R7 is a divalent organic radical of 1
to 20 carbon atoms selected from the group consisting of
alkylene, cycloalkylene, alkenylene, arylene, alkylidene and
; cycloalkylidene radicals; and n is an integer from 1 to
20.
These organotin plasticizers can be prepared by methods
known in the art such as is described in Kirk-Othmer's
Encyclopedia of Chemical Technology, second edition, 1969,
Vol. 20, pp. 304-327, as well as in the references cited
therein.
The amount of organotin plasticizer employed in the
practice of this invention can be from about 0.005 - 1.0
parts per hundred parts of aromatic carbonate polymer,
preferably from about 0.01 - 0.5 parts per hundred parts
of aromatic carbonate polymer.
The high molecular weight aromatic polycarbonates
that can be employed herein are homopolymers and copolymers
and mixtures thereof which have an intrinsic viscosity
(I.V.) of 0.40 to 1.0 dl/g as measured in methylene
chloride at 25C and which can be prepared by reacting a
dihydric phenol with a carbonate precursor. Typical of
some of the dihydric phenols that can be employed are bis-
phenol-A, (2,2-bis(4-hydroxyphenyl) propane), bis(4-
hydroxyphenyl)methane, 2,2-bis(4-hydroxy-3-methylphenyl)
propane and 4,4-bis(4-hydroxyphenyl)heptane. Other
halogen-free dihydric phenols of the bisphenol type are
also available and are disclosed in U.S. Patents 2,999,835
dated September 12, 1961 to Goldberg, 3,028,365 to Schnell
~~ 8CL-3451
dated April 3, 1962 and U.S. Patent 3,334,154 to Kim dated
August 1, 1967.
Of course, it is possible to employ two or more different
dihydric phenols or a copolymer of a dihydric phenol with
a glycol or with hydroxy or acid terminated polyester, or
with a dibasic acid in the event a carbonate copolymer or
interpolymer rather than a homopolymer is desired for use
in the preparation of the aromatic carbonate polymers of
this invention. In addition, blends of any of these
materials can also be employed to provide the aromatic
carbonate polymer provide they are free of halogen.
The carbonate precursor can be either a carbonyl halide,
a carbonate ester or a haloformate. The carbonyl halides
which can be employed are carbonyl bromide, carbonyl chloride
and mixtures thereof. Typical of the carbonate esters
which can be employed are diphenyl carbonate, di-(halophenyl)
carbonates such as di(chlorophenyl) carbonate, di-(bromophenyl)
carbonate, di-(trichlorophenyl) carbonate, di-(tribromophenyl)
carbonate, etc., di-(alkylphenyl) carbonates such as di(tolyl)
carbonate, etc., di-(naphthyl) carbonate, di-(chloronaphthyl)
carbonate, phenyl tolyl carbonate, chlorophenyl chloronap-
hthyl carbonate, etc. or mixtures thereof. Suitable halo-
formates include bishaloformates of dihydric phenols
(bischloroformates of hydroquinone, etc.) or glycols
(bishaloformates of ethylene glycol, neopentyl glycol,
polyethylene glycol, etc.). While other carbonate precursors
will occur to those skilled in the art, carbonyl chloride,
also know as phosgene, is preferred.
Also included are the polymeric derivatives of a dihy-
dric phenol, a dicarboxylic acid and carbonic acid. Theseare disclosed in U.S. Patent No. 3,169,121 to Goldberg
dated February 9, 1965.
-- 4 --
~ S7~5 8cL-345l
The aromatic polycarbonates of this invention can be
prepared by employing a molecular weight regulator, an acid
acceptor and a catalyst. The molecular weight regulators
which can be employed include monohydric phenols such as
phenol, chroman-I, paratertiary-butylphenol, parabromophenol,
primary and secondary amines, etc. Preferably, phenol is
employed as the molecular weight regulator.
A suitable acid acceptor can be either an organic
or an inorganic acid acceptor. A suitable organic acid
acceptor is a tertiary amine and includes such materials
as pyridine, triethylamine, dimethylaniline, tributylamine,
etc. The inorganic acid acceptor can be one which can
either hydroxide, a carbonate, a bicarbonate, or a phosphate
of an alkali or alkaline earth metal.
The catalysts which can be employed are any of the
suitable catalysts that aid the polymerization of bis-
phenol-A with phosgene. Suitable catalysts include tertiary
amines such as, for example, triethylamine, tripropylamine,
N,N-dimethylaniline, quaternary ammonium compounds such as,
for example, tetraethylammonium bromide, cetyl triethyl
ammonium bromide, tetra-n-heptylammonium iodide, tetra-n-
propyl ammonium bromide, tetramethylammonium chloride,
tetramethyl ammonium hydroxide, tetra-n-butyl ammonium
iodide, benzyltrimethyl ammonium chloride and quaternary
phosphonium compounds such as, for example, n-butyltri-
phenyl phosphonium bromide and methyltriphenyl phosphonium
bromide.
Also, included herein are branched polycarbonates
wherein a polyfunctional aromatic compound is reacted with
the dihydric phenol and carbonate precursor to provide a
thermoplastic randomly branched polycarbonate.
These polyfunctional aromatic compounds contain at least
~57~5 8CL-3451
three functional groups which are carboxyl, carboxylic
anhydride, or mixtures thereof. Examples of these poly-
functional aromatic compounds which can be employed include
trimellitic anhydride, trimellitic acid, 4-chloroformyl
phthalic anhydride, pyromellitic acid, pyromellitic
dianhydride, mellitic acid, mellitic anhydride, trimesic
acid, benzophenonetetracarboxylic acid, benzophenonetetra-
carboxylic anhydride and the like. The preferred poly-
functional aromatic compounds are trimellitic anhydride or
trimellitic acid.
Also, included herein are blends of a linear poly-
carbonate and a branched polycarbonate.
The polycarbonate composition of the invention is
prepared by blending the high molecular weight aromatic
polycarbonate with the organotin plasticizer by employing
conventional methods.
PREFERRED EMBODIMENTS OF THE INVENTION
The following examples are set forth to more fully
describe the invention. Accordingly, the examples should
be construded as being illustrative and not limitative of
the invention. In the examples, all parts are percentages
are on a weight basis unless otherwise specified.
EXAMPLE 1
One hundred (100) parts of an aromatic, halogen-free
polycarbonate prepared from 2,2-bis(4-hydroxyphenyl) propane
(bisphenol-A) and phosgene in the presence of an acid
acceptor and a molecular weight regulator and having an
intrinsic viscosity of about 0.57, was mixed with the
plasticizer listed in the Table by tumbling the ingredients
together in a laboratory tumbler. The resulting mixture
was then fed to an extruder which was operated at about
265C, and the extrudate was comminuted into pellets.
~57~85 8CL-3451
The pellets were then fed into a plasticizer and
the flow rate of polymer was measured according to ASTM
D1238-70, Condition O. The melt flow rate is set forth
in the Table.
Additionally, the pellets were injection molded at
about 315C into test specimens of about 5 by 1/2 by 1/8
inch thick. The impact strength of these specimens was
then measured according to the Izod test, ASTM D256 and
the results obtained are also set forth in the Table.
The sample labeled CONTROL is the polycarbonate prepared
without plasticizer.
~ ~t 57~85 8CL 34 51
-
,S: H
C~ ~ .
. .
~ _
o o O
~1 ~ ~1 ~D O O ~ n ~`I o o ~ o ~ c~ 1` 0
. o ~ cc~ o _I 1` o ~ ~ ao r~
~I t1
a)--
~ _ ~
o Q ~ ,~ ~ ~ ~ _I ~ _
~ Q I ~ o o,~ o o o o o o o _
~;--
~1
X
o
X ~ ,
o U~
--~ -- X
x
X x ~ ~ >1 0 0
O Orq ~ ~ ~.,, ~ x a~
s~ ~ o
~ a) o o X ~ ~ ~ ~ er a) ~1 ~ a
N ~ O
.~ llS ~ ~ ~1 --X ~a~ ~1 o ~I t~ tO
~ ~ O O ~ ~ O ~ U~ I
,~ s~ x ~ X ~1 a) o rC ~n
o oa~ o ~ o ~ x
~n ~ X X ~ ~ ~ o Q~ X ~
U~ o o ~ O ~n
~1 H I l X ~ U~ l N ~
r~ O ~)~a ~ IVJ V~ Q ~
.,1 ~ ~ ~ O O ~ ~ ~ I
~J ~:1 o ~ ~ x x ~ o x o
o o ~ a) o o o ~~u o x
~: ~ I I A ~ ~ O ~ ~ ~ Q~
~ E~ O ~
tJ~ Z ~ ~1 ~1 ---- X ~ ~1~ A A A X
s~ o a) s~ 1 o
O C~ a ~ a ~ :~
~57~8S
8CL-3451
It can be seen from the data in the Table that when
the halogen-free organotin plasticizers of the invention
are added to a halogen-free high molecular weight aromatic
polycarbonate, the resulting polycarbonate composition
has reduced melt viscosity as shown by the higher melt
flow rate while retaining impact strength.
