Note: Descriptions are shown in the official language in which they were submitted.
?4!393
8CL-3605
GRAPHITE FILLED POLYESTER-CARBONATE COMPOSITIONS
This invention relates to reinforced thermo-
plastic molding compositions. More particularly, it
relates to thermoplastic molding compositions containing
a polyester-carbonate resin and graphite fibers.
BACKGROUND OF THE INVENTION
,
Polyester-carbonate resins and the methods for
their preparation are well known in the art as disclosed
in U.S. Patents 3,303,331, Looker et al, issued January
31, 1967; 3,169,121, Goldberg, issued February 9, 1965
and 3,207,814, Goldberg, issued September 21, 1965.
Other prior art disclosures of polyester-carbonates and
methods of their preparation include U.S. Patent 4,189,549,
Matsunaga, issued February 19, 1980, which discloses
polyester-carbonate compositions which are obtained
from a melt polymerization process employing para
hydroxy benzoic acid; U.S. Patent 4,156,069, Prevorsek,
issued May 22, 1979 r which discloses a process for
preparing an alternating ester-carbonate block copolymer
from dihydric phenols, dicarboxylic acid dihalides,
phosgene and a molecular weight regulator all in the
presence of pyridine; and U.S. Patent 4,194,038,
Baker et al, issued March 18, 1980, which discloses a
process for preparing poly(ester-carbonates) from
dihydric phenols, especially bisphenol A, aromatic or
cycloalipha~c dicarboxylic acids, especially
terephthalic acid, and phosgene as a carbonate
precursor wherein a reaction os the acid and phosgene
is carried out in a first stage forming dicarboxylic
acid chloride and then phosgene and bisphenol A are
added in separate streams, simultaneously during most
of the second or condensation stage.
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8CL-2605
Canadian Application Serial Number
350,529, filed April 24, 1980 and assigned -to the same
assignee as the instant application discloses copoly-
ester-carbonate compositions employing diacid chloride
copolymers in the preparation of the polyester portion
of the polyester-carbonate.
The use of these polyester-carbonates is
desirable as such resins are in general easy to process
and result in economic savings in both manufacturing
and materials cost. However, the use of these resins
is somewhat limited as they do not generally exhibit
all of the highly desirable physical properties of
high molecular weight aromatic polycarbonates.
DESCRIPTION OF T~IE INVENTION
It has now been found that polyester-carbonate
resin compositions can be obtained whose physical
properties permit them to be used in a broader range of
applications than was previously possible. This is
accomplished by adding graphite fibers to the polyester-
carbonate resin composition.
The preparation of polyester-carbonates which
may be employed in the compositions of the present
invention is described in U.S. Patents, 3,030,331,
Goldberg, issued April 17, 1962, 3,169,121, Looker et al,
issued January 31, 1967 and 4,194,038, Baker, issued
March 18, 1980 and 4,156,069, Prevorsek, issued May
22, 1979, as well as in co-pending application
Serial No. 350,529, ~iled April 24l 1980 and assigned
to the same Assignee as the instant application.
The polyester-carbonates can generally be
termed copolyesters containing carbonate groups,
carboxylate groups, and aromatic carbocyclic groups
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8CL~3605
in the polymer chain, in which at least some of the
carboxylate groups and at least some of the carbonate
groups are bonded directly to ring carbon atoms of the
aromakic carbocyclic groups. These polyester-carbonates
are, in general, prepared by reacting a difunctional
carboxylic acid or a reactive derivative of the acid
such as the acid dihalide, a dihydric phenol and a
carbonate precursor.
The dihydric phenols useful in formulating
the polyester-carbonates useful in the practice of
the present invention in general are represented by
the general formula
~(Y)ml ~(R)~ ~(Y) ~
I HO ~ A ~ ~ ~ l ~ OH
in which A represents an aromatic group such as phenylene,
biphenylene, naphthylene, etc. E may be an alkylene or
alkylidene group such as methlene, ethylene, propylene,
propylidene, isopropylidene, butylene, bu-tylidene,
isobutylidene, amylene, isoamylene, amylidene,
isoamylidene, etc. Where E is an alkylene or alkylidene
group, it may also consist of t~o or more alkylene or
alkylidene groups, connected by a non-alkylene or non-
alkylidene group such as an aromatic linkage, a
tertiary amino linkage, an ether linkage, a carbonyl
linkage, a silicone-containing linkage, or by a
sulfur-containing linkage such as sulfide, sulfoxide,
sulfone, etc. In addltion, E may be a cycloali-
phatic group (e.g. cyclopenty], cyclohexyl~; a sulfur-
containing linkage, such as sulfide, sulfoxide or
sulfone; an ether linkage; a carbonyl group, a tertiary
8CL-3605
nitrogen group; or a silicon-containing likage such as
silane, or siloxy. Other groups which E may represent
will occur to those skilled in the art. R represents
hydrogen or a monovalent hydrocarbon group such as
alkyl (methyl, ethyl, propyl, etc.), aryl (phenyl,
naphthyl, etc.), aralkyl (benzyl, ethylphenyl, etc.),
or cycloaliphatic (cyclopentyl, cyclohexyl, etc.). Y
may be an inorganic atom such as a halogen (fluorine,
bromine, chlorine, iodine), an inorganic group such
as the nitro group, an organic group such as R above,
or an oxy group such as OR, it being only necessary
that Y be inert to and unaffected by the reactants
and the reaction conditions. The letter m represents
any integer from and including zero through the number
of positions on A available for substitution; p
represents an integer from and including zero through
the number of positions on E available for substitution;
t represents an integer equal to at least one; s is
either zero or one; and u represents an integer including
zero.
In the dihydric phenol compound represented
by Forumula I above, when more than one Y substituent
is present, they may be the same or di~ferent. The
The same holds true for the R substituent. Where s is
zero in Forumula I and u is not zero, the aromatic
rings are directly joined with no intervening alkyl-
ene or other bridge. The positions of the hydroxyl
groups and Y on the aromatic nuclear residues A can
be varied in the ortho, meta or para positions and the
groupings can be in a vicinal, asym~etrical or symmetri-
cal relationship, where two or more ring carbon atoms
of the aromatic hydrocarbon residue are substituted with
Y and hydroxyl group.
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Some nonlimiting examples of dihydric phenol
compounds falling within the scope o Forumla I which
can be used in the preparation of the polyester-carbon-
ates useful in the practice of the present invention
include:
2,2-bis-(4-hydroxyphenyl)-propane (bisphenol A);
2,4'-dihydroxydiphenylmethane;
bis-(2-hydroxyphenyl)-methane;
bis-(4-hydroxyphenyl)-methane;
bis-(4-hydroxy-5-nitrophenyl)-methane;
bis-(4-hydroxy-2,6-dimethyl-3-methoxyphenyl)-methane;
1,1-bis-(4-hydroxyphenyl)-ethane;
1,1-bis-(4-hydroxy-2-chlorophenyl)-ethane;
2,2-bis-(3-phenyl-4-hydroxyphenyl3-propane;
bis-(4-hydroxyphenyl)-cyclohexylmethane; and
2,2-bis-(4-hydroxyphenyl)-1-phenylpropane.
These dihydri~ phenols may be used alone or
as mixtures of two or more different dihydric phenols.
In general any difunctional carboxylic acid,
or its reactive derivative such as the acid dihalide,
conventionally used in the preparation of polyesters
may be used for the preparation of the polyester-
carbonates useful in formulating the compositions
of the present invention. In general the carboxylic
acids which may be used are aliphatic carboxylic acids,
aliphatic-aromatic carboxylic acids, or aromatic
carboxylic acids. The aromatic dicarboxylic acids or
their derivatives such as the aromatic acid dihalids
are preferred as they produce the aromatic polyester-
carbonates wh:ich are most useful in the practice ofthe instant invention.
These carbocylic acids may be represented by
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the general formula
II. R { R ~ COOH
wherein Rl represents an alkylene, alkylidene or
cycloaliphatic group in the same manner as set ou-t
above for E in Formula I; an alkylene, alkylidene or
cycloaliphatic group containing ethylenic unsaturation;
an aromatic radical such as phenylene, naphthylene,
biphenylene, substituted phenylene, etc.; two or more
aromatic groups connected through non-aromatic linkages
such as those defined by E in Forumla I; or an aralkyl
radical such as tolylene, xylene, etc. R is either
a carboxyl or a hydroxyl group. The letter q represents
on where R is a hydroxyl group and either zero or one
where R is a carboxyl group. Thus the difunctional
acid will either be a monohydroxyl ~monocaxboxylic~
acid or a dicarboxylic acid. For purposes of the
present invention the dicarboxylic acids or their
reactive derivatives such as the acid dihalides are
preferred.
As mentioned previously the aromatic dicar-
boxylic acids are preferred. Thus in these preferred
acids R2 is a carboxyl group and Rl is an aromatic
radical such as phenylene, naphthylene, biphenylene,
substituted phenylene, etc.; two or more aromatic
groups connected through non-aromatic linkages; or an
aralkyl radical. Some non-limitlng examples of
suitable preferred aromatic and aliphatic-aromatic
dicarboxylic acids which may be used in preparing
the polyester-carbonates useful in the practice of
the present invention include phthalic, isophthalic,
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terephtalic, homophthalic, o-, m-, and p-phenylene-
diacetic acid; the polynuclear aromatic acids such
as diphenic acid, and l,~-naphthalic acid.
These acids may be used either alone or as
mixtures of two or more different acids.
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-(halo-
phenyl) carbonates such as di-(chlorophenyl)carbonate,
di-(bromophenyl) carbonate, di-(trichlorophenyl)
carbonate, di-(tribromophenyl) carbonate, etc.,
di-(alkylphenyl) carbonate, such as di-(tolyl)
carbonate, etc., di-(naphthyl) carbonate, di-(chloro-
~aphthyl carbonate, phenyl tolyl carbonate, choro-
phenyl chloronaphth~1 carbonate, etc., or mixtures
thereof. The haloformates suitable for use herein
include bis-haloformates 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 known as phosgene, is preferred.
The polyester-carbonates which are preferred
in the practice of the present invention are the
aromatic polyester-carbonates derived from dihydric
phenols, aromatic dicarboxylic acids or their reactive
derivatives such as the aromatic acid dihalides, e.~.,
di-chlorides, and phosgene. A quite useful class of
aromakic polyester-carbonates are those derived from
~2~ 3 8CL-3605
bisphenol A, aromatic dicarboxylic acids or -their reactive
derivatives such as terephthalic or isophtalic acid or
terephthaloyl or isophthaloyl dichloride, and phosgene.
Some particularly useful aromatic polyester-carbonates
are those derived from bisphenol A, a mixture of
isophthalic and terephthalic acids or isophthaloyl
dichloride and terephthaloyl dichloride in a weight
ratio of from 5:95 to 95:5, and phosgene.
The polyester-carbonate compositions of
the instant invention are formulated by admixing
graphite fibers with the polyester-carbonate resin.
These graphite fibers may generally have a diameter
of between about 0.1 and OoO01 millimeters, and
preferably have a diameter between about 0.05 and about
0.005 millimenters. Such graphite fibers are
commercially available and are marketed, for example,
by Celanese under the tradename Celion and by Union
Carbide under the tradename Thornel.
The amount of the graphite fibers employed
in the practice of this invention may generally vary
from between about 0.5 to about 45 weight percent based
on the weight of the polyester-carbonate resin compo-
sition~ Preferably the composition contains from about
5 to about 30 weight percent of the graphite fibers,
and more preferably from about 10 to about 20 weight
percent of the graphite fibers. Generally if less
than about 0.5 weight percent of the graphite fibers
are employed in the composition there is usually no
appreciable improvement in the physical properties of
the polyester-carbonate composition. If, on the
other hand, the composition contains more than about
3 8CL-3605
~5 weight percent of the graphite fibers the physical
properties, such as impact strength and processability,
of the resin compostion begin to be adversely affected
thereby reducing the usefulness of the resin composition
in providing molded articles of good quality.
The addition or incorporation of these
graphite fibers in the aforedescribed amounts in a
polyester-carbonate composition results in a compo-
sition having improved heat distortion, flame retard-
ance, rigidity and electrical conductivity. Thegraphite fibers are added to the polyester-carbonate
resins and are mixed or blended therewith by generally
mechanical means such as stirring, shaking, blending in
a mechanical blender, etc., to form the compositions of
the present invention.
The compositions of the present invention
may optionally contain other commonly known and used
additives such as anti-static agents, antioxidants,
mold reI~ase agents, colorants, glass fibers, impact
modifiers, stabilizers, fillers, and flame retardants.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The following examples are set forth to
further illustrate the present invention and are not
to be construed as limiting the invention thereto.
Unless otherwise specified, where parts or percents
are mentioned, they are parts or percents by weight.
_XAMPLE 1
This example illustrates the preparation
of an aromatic polyester-carbonate derived from
bisphenol A, a mixture of terephthaloyl dichloride
and isophthaloyl dichloride, and phosgene~
The resin of this example is prepared by
following the single pH profile disclosed in copending
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8CL-3605
Canadian Application Serial No. 343,169 filed
January 7, 1980 of common assignee.
To a ten gallon reactor vessel there are
added 8 liters of methylene chlorine, 6 liters of
water, 1906 grams (8.36 moles) of bisphenol A, 20
milliliters of triethylamine, 4 grams of sodium
gluconate, and 125 grams of chroman (I) (93% purity)
chain terminator. At a pH of between about 9-10.5,
1089.6 grams (5.37 moles) of a mixture of 15% by weight
of isophthaloyl dichloride and 85% by weight terephthaloyl
dichloride in two liters of methylene chloride are
added over a 10 minute interval while controlling the
pH at about 9-10.5 with 35% aqueous caustic. After
the addition of the diacid chloride mixture, phosgene
is added at a rate of 36 grams per minute for 12
minutes while controlling the pH at about 10-11 with
35% aqueous caustic. The polymer mixture is diluted
with 5 liters of methylene chloride and the brine
phase is separated. The resulting polymer phase is
washed with O.lN HCl (twice) and water (three times)
and is then recovered by high pressure steam pre-
cipitation to yield a white powder having an IV of
0.5 dl/g in methylene chloride. To this powder are
added minor amounts (less than about one part per
hundred parts of resin) of a phosphite stabilizer and
an epoxy stabilizer. This resin product is then fe~
to an extruder operating at a temperature of about
600F to extrude the resin into strands and the
ext~uded strands are chopped into pellets. The pellets
are then injection molded at about 650~ in-to tes-t
samples measuring about 2.5" x 1/2" x 1/8"~
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EXAMPLE 2
This example illustrates a polyester-carbonate
composition falling outside the scope of the present
invention.
A polyester-carbonate resin is prepared
substantially in accordance with the procedure of
Example 1. To the powdered polyester-carbonate
resin is added glass fiber in an amount of 10% by
weight of the resin composition. The glass and resin
powder are mixed by tumbling the ingredients together
in a laboratory tumbler. The mixture is then fed to
an extruder operating at a temperature of about 600F
to extrude the resin composition into strands and the
extruded strands are chopped into pellets. The pellets
are then injection molded at about 650F into test
samples measuring about 2.5" x l/2" x l/8".
EXA~lPLE 3
This example also illustrates a polyester-
carbonate composition falling outside the scope of
the instant invention.
A polyester-carbonate resin is prepared
substantially in accordance with the procedure of
Example 1. To the powdered polyester-carbonate resin
is added glass fiber in an amount of 20% by weight of
the resin composition. The glass and the resin powder
are mixed by tumbling the ingredients together in a
laboratory tumbler. The mixture is then fed -to an
extruder operating at a temperature of about 600~
to extrude the resin composition into strands and the
extruded strands are chopped into pellets. The pellets
are then injection molded at about 650F into test
samples measuring about 2.5" x l/2" x 1/8".
~)4i5 93 8CL-3605
EXAMPLE 4
This example illustrates a polyester-
carbonate composition falling within the scope of the
present invention.
A polyester-carbonate resin is prepared
substantially in accordance with the procedure of
Example 1. To the powdered polyester-carbonate
resin are added graphite fibers in an amount of 10%
by weight of the resin composition. The graphite
fibers and the resin powdex are mixed by tumbling the
ingredients together in a laboratory tumbler. The
mixture is then fed to an extruder operating at a
temperature of about 600F to extrude the composition
into strands and the extruded strands are chopped
into pellets. The peIlets are then injection
molded at about 650F into test samples measuring
about 2.5" x 1/2" x 1/8".
E~AMPLE 5
This example illustrates a polyester-
carbonate composition of the present invention.
A polyester-carbonate resin is prepared
in substantial accordance with the procedure of
Example 1. To the powdered resin are added graphite
fibers in an amount of 20% by weight of the resin
composition. The fibers and the resin are mixed by
tumbling the ingredients together. The mixture is
then fed to an extruder operating at a temperature
of about 600F to extrude the composition into strands
and the extruded strands are chopped into pellets.
The pellets are then injection molded at about 650 F
into test sarnples measuring about 2.5" x 1/2" x 1/8".
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Various physical properties of the test
samples obtained in Example 1-5 were determined
according to the following test procedures:
Heat Distortion Temperature Under Load
(DTUL) of the molded samples was determined accordiny
to ASTM D-648;
Notched Izod (NI) and Unnotched Izod (UNI)
impact on the 1/8" thick molded samples were
determined according to ASTM D-256;
Flexural Yield (FY) and Flexural Modulus
~FM) were determined according to ASTM D-790;
Flame Ret~rdanc~ (FR) of the molded samples
was determined by subjecting the sample (5 samples
for each Example) to the test procedures set forth
in Underwriters' Laboratories, Inc. Bulletin UL-94,
Burning Test for Classifying Materials, In accordance
with this test procedure,~te~ials so investigated are
rated either V-O, V-I or V-II based on the results of
5 specimens. The criteria for each V (for vertical)
rating per UL-94 is briefly as follows:
"~-0": Average flaming and/or glowing after
removal of the igniting flame shall
not exceed 5 seconds and none of the
speciments shall drip flaming particles
which ignite absorbent cotton.
"V-I": Average flaming and/or glowing a4ter
removal of the igniting flame shall
not exceed 25 seconds and the glowing
does not travel vertically for more
than l/8" of the specimen after
flaming ceases and glowing is incapable
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igniting-absor~n-t cotton.
"V-II": Average flaming and/or glowing after removal
of the igniting flame shall not exceed 25
seconds and the specimens drip flaming particles
which ignite absorbent cotton.
In addition, a ~est bar which continues to burn for more than
25 seconds after removal of the igniting flame is classified,
not by UL-94 but by the standard of the present invention, as
"burns". Further, UL-94 requires that all test bars in each test
group must meet the V-type rating to achieve that particular
classification. Otherwise, the 5 bars receive the rating of the
worst single bar.
The res~lts of these tests are set forth in Table I.
TABLE I
Example Example Example Example Example
~Y) 13,800 16,300 23,600 22,60028,~00
, p.s.i. p.s.i. p.s.i. p.s.i.p.s.i.
~FM) 319,00Q ~74,000718,000 797,0001,420,000
p.s.i. p.s.i. p.s.i. p.s.i.p.s.i/
(DTUL) 165C. 176'C. 179C. 180C. 181C.
(NI~ 7.3 2.7 2.4 1.5 1.4
ft.lb./ ft. lb./ ft~lb./ ft. lb.J ft. lb.l
in. width in. w. in. w. in. w. in. w.
(UNI) ~ 40 29.1 16.3 9.6 10.2
ft. lb./ ft.lb./ ft.b./ f~.lb./ ft.lb./
in. w. in. w. in.w. in.w. in.w.
(FR)* Burns Burns V-II V-I V-II
....... ........
J'; The test samples were l~i6 inch thick.
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As can be seen from the data in Table I the
graphite fiber filled polyester-carbonate compositlons,
i.e., Examples 4 and 5, have a high flexural yield
(FY) and flexural modulus (FM) than the unfilled
polyester-carbonate resin, i.e., Example l, and the
polyester-carbonate compositions which contain
comparable amounts of glass fibers, i.e., Examples 2 and
3. Furthermore, there is a dramatic increase in the
heat distortion temperature of the graphite filled
compositions as compared to the unfilled polyester-
carbonate resln and a significant increase as compared
to the glass fiber filled polyester-carbonate
compositions.
Furthermore, the graphite fiber containing
polyester~arbonate compositions of Examples 4 and 5
exhibit superior flame retardancy than the unfilled
polyester-carbonate resin of Example l and the
glass fiber filled polyester-carbonate compostiions
of Examples 2 and 3.
It will thus be seen that the objects set
forth above among those made apparent from the
preceding description are efficiently attained from
and since certain changes may be made in the processes
and compositions described above 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.
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