Note: Descriptions are shown in the official language in which they were submitted.
~ CH-2554
This invention is directed to a plasticized polycarbonate
composition comprising in admixture a high molecular weight
aromatic carbonate polymer and a minor amount of an oligo-
polymeric siloxane plasticizer.
Polycarbonate polymers are excellent molding materials
as products made therefrom have high impact strength,
toughness, high transparency, wide temperature limits (high
impact resistance below -60C and a UL thermal endurance
rating of 1150C 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 for the reason that melts thereof have exception-
ally high viscosities. Attempts to overcome this difficulty
by the incorporation with the polycarbonate of materials
known to reduce the viscosity of other resins have very
generally been unsuccessful. Many standard viscosity
control agents appear to have little or no effect on the
viscosity of polycarbonate. Other compounds known to lower
the viscosity of resins cause degradation of polycarbonate
resins. Some compounds, conventionally employed to im-
provie the workability of polymers, produce an embrittling
effect on polycarbonates when they are mixed therewith and
the resin is subjected to elevated temperatures as in molding.
Still other materials, while satisfactory stiffness modify-
ing agents for other plastics, are too volatile to be in-
corporated agents for other plastics, are too volatile to
be incorporated with polycarbonates since polycarbonates
have much higher melting points than many other thermo-
plastics.
It has been surprisingly discovered that, by admixing
a minor amount of an oligo-polymeric siloxane plasticizer
-- 1 --
3CH-2594
with a high molecular weight aromatic carbonate polymer,
the resultant polycarbonate composition has reduced melt
viscosity and does not become brittle or degraded upon molding
and thus retains its characteristic high impact strength.
In the practiee of this invention, the oligo-polymerie
siloxane plasticizers are characterized by the following
formulae:
~ ~ ~ CH ~ +
(b) ~ 5 - 0 - ~ CH ~ ~ -20
(c) ' ~ ~
C,H3
--si - o _
CH2
CH2 - COOCH3 i
. 35
(d) L ~ o ~
4-20
(e)
- ,CH3 , 3
_ - Si 0 - CH - C - CH - 0 -
CH3 C 3
4-20
-- 2 --
,
~CH-2594
~f) CH3
--si - o _
CH2
,CH2
CN 35
(g) CH3
--si - o
C=O
NH
C18H37 35
These oligo-polymeric siloxane plasticizers are prepared
by well known methods in the art such as from the corresponding
dichloro silicone precursor with the dihydroxy compound in the
presence of bases.
The amount of oligo-polymeric siloxane plasticizer
employed in the prackice of thîs invention may vary from 0.05 to
about 5.0 parts per hundred parts of aromatic carbonate polymer.
Preferably, these organic plasticizers are employed in amounts of
from 0.25 to 2.0 parts per hundred parts of aromatic carbonate
polymer.
In the practice of this invention, the high molecular
weight aromatic polycarbonates that can be employed herein are
homopolymers and copolymers and mixtures thereof which have
an I.V. of 0.40 to 1.0 dl./g. as measured in methylene
chloride at 25C that are prepared by reacting a dihydric
phenol with a carbonate precursor. Typical of some of the
dihydric phenols that may be employed in the practice of
this invention are bisphenol-A (2,2-bis(4-hydroxyphenyl)-
propane), bis(4-hydroxyphenyl)methane, 2,2-bis(4-hydroxy-
3-methylphenyl)propane, 4,4-bis(4-hydroxyphenyl)heptane,
2,2-(3,5,3',5'-tetrachloro-4,4'-dihydroxydiphenyl)propane,
(3,3'-dichloro-4,4'-dihydroxydiphenyl)methane. Other dihydric
phenols of the bisphenol type are also available and are dis-
- 3 -
,. ..
~ 8CH-2594
, , .
closed in U.S. Patents 2,999,835 dated September 12, 1961
3,028,365 dated April 3, 1962 and U.S. patent No 3,334,154
dated August 1, 1967.
It is, oE course, possible to employ two or more dif-
ferent dihydric phenols or a copolymer of a dihydric phenol
with a ylycol or with hydroxy or acid terminated polyester,
or with a dibasic acid in the event a carbonate copolymer
or inter-polymer rather than a homopolymer is desired for
use in the preparation of the aromatic carbonate polymers
of this invention. Also employed in the practice of this
invention may be blends of any of the abo~e materials to
provide the aromatic carbonate polymer.
The carbonate precursor may be either a carbonyl
halide, a carbonate ester or a haloformate. The carbonyl
halides which can be employed herein are carbonyl bromide,
carbonyl chloride and mixtures thereof. Typical of the
carbonate esters which may be employed herein are diphenyl
carbonate, di-(halophenyl) carbonates such as di-(chloro-
phenyl) carbonate, di-(bromophenyl) carbonate, di-(trich-
lorophenyl) carbonate, di-(tribromophenyl) carbonate, etc.,
di-(alkylphenyl) carbonates such as di(tolyl) carbonate,
etc., di-(naphthyl) carbonate, di-(chloronaphthyl) car-
bonate, phenyl tolyl carbonate, chlorophenyl chlorona-
phthyl carbonate, etc., or mixtures thereof. The halofor-
mates suitable for use her~in include bis-haloformates of
dihydric phenols (bischloroformates of hydroquinone, etc.)
or glycols (bishaloformates of ethylene glycol, neopentyl
glycol, polyphenylene glycol, polyethtlene glycol, etc.).
While other carbonate precursors will occur to those skilled
in the art, carbonyl chloride, also known as phosgene, is
preferred.
Also included are the polymeric derivatives of a dihy-
4 --
- ~3~ 8C~1-2594
dric phenol, a dicarboxylic acid and carbonic acid. These are
disclosed in U.S. Pat 3,169,131 dated Feb/9/1965.
These aromatic carbonate polymers of this invention may
be prepared by employing a molecular weight regulator, an acid
acceptor and a catalyst. The molecular weight regulators which
can be employed in carrying out the process of this invention in-
clude monohydric phenols such as phenol, chroman-I, paraterti-
arybutylphenol, parabromophenol, primary and secondary amines,
etc. Preferably, phenol is employed as the molecular weight
regulator.
A suitable acid acceptor may 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, et. The inorganic
acid acceptor may be one which can be either a hydroxide, a
carbonate, a bicarbonate, or a phosphate of an alkali or
alkaline earth metal.
The catalysts which are employed herein can be any of the
suitable catalysts that aid the polymerization of bisphenol-A
with phosgene. Suitable catalysts include tertiary amines such
as, for example, triethylamine, tripropylamine, N,N-dimethyl-
aniline, quaternary ammonium compounds such as, for example,
tetraethylammonium bromide, cetyl triethyl ammonium bromide,
tetra-n-heptylammonium iodie, 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-butyltriphenyl phosphonium bromide and methyl-
triphenyl 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 ran-
domly branched polycarbonate.
8CH-2594
33~
These polyfunctional aromatic compounds contain at least
three functional groups which are carboxyl, carboxylic
anhydride, haloformyl or mixtures thereof. Examples of
these polyfunctional aromatic compounds which may be employed
in the practice of this invention include: trimellitic anhy-
dride, trimellitic acid, trimellityl trichloride, 4-chloro-
formyl phthalic anhydride, pyromellitic acid, pyromellitic
dianhydride, mellitic acid, mellitic anhydride, trimesic
acid, benzophenonetetracarboxylic acid, benzophenonetet-
racarboxylic anhydride and the like. The preferred poly-
functional aromatic compounds are trimellitic anhydride or
trimellitic acid or their haloformyl derivatives.
Also, included herein are blends of a linear poly-
carbonate and a branched polycarbonate.
The composition of the instant invention is prepared
by blending the high molecular weight aromatîc poly-
carbonate with the additive by conventional methods.
Obviously, other materials can also be employed with
the aromatic carbonate polymer of this invention and
include such materials as anti-static agents, pigments,
thermal stabilizers, ultraviolet stabilizers, reinforcing
fillers and the like.
In order to more full and clearly illustrate the
present invention, the following specific examples are
presented. It is intended that the examples be considered
as illustrative rather than limiting the invention dis-
closed and claimed herein. In the examples, all parts and
percentages are on a weight basis unless otherwise specified.
One hundred (100) parts of an aromatic polycarbonate,
prepared from 2,2-bis(~-hydroxyphenyl) propane and phosgene
in the presence of an acid acceptor and a molecular weight
regulator and having an intrinsic viscosity of about 0.57,
~ 33~ 8CH-2594
is mixed with the additive listed in the Table by tumbling
the ingredients together in a laboratory tumbler. The
re~ulting mixture is then fed to an extruder which is operated
at about 265 C, and the extrudate is comminuted into pellets.
The pellets are then fed into a plastomer and the flow
rate of the polymer is measured according to ASTM D1238-70,
condition 0. The melt flow rate is set forth in the Table,
Additionally, the pellets are 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 is then
measured according to the Izod test, ASTM D-256. The
impact strength is set forth in the Table. The sample
labeled CONTROL is the polycarbonate as prepared without
additive.
~L6331 8CH 2 5 9
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al h
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h
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4~ I I o ~ o ,1
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s ~ ~ ;3~3~3L 8CH 25g4
a~
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X 'U, ~ ~ 'U, ~ ~ . ~-- V--V--V
.633~ 8CH 2594
G
a) H
h
u~ u~
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r
I~ . ,~
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a
a~
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~3CH-~594
It can be seen from the data in the Table that when
the instant oligo-polymeric siloxane plasticizer is added to
a high molecular weight aromatic polycarbonate, the re-
sulting polycarbonate composition has reduced melt viscosity
as shown by the higher melt flow rate while retaining impact
strength.
It will thus be seen that the objects set forth above among
those made apparent from the preceding description are ef-
ficiently attained and since certain changes may be made in
carrying out the above process and in the composition set
forth without departing from the scope of this invention,
it is intended that all matters contained in the above
description shall be interpreted as illustrative and not
in a limiting sense.
~_
