Note: Descriptions are shown in the official language in which they were submitted.
8CL--6838
BLOW--MOLDABLE POLYCARBONATE RESIN COMPOSITIONS
_~ ___ OF ~ GH IM~.ACT STRENGTH
BACRGROUND OF THE I ~ NTION
Field of the Invention
~ he invention relates to thermoplastic resin
compositions and ~ore particularly relates to
improved, blow-moldable polycarbonate resin
compositions and artieles molded therefrom.
Brief Description of th~e ~ior Art
Aromatic polycarbonate resins are a well known
class of synthetic polymeric resins, generally
prepared by the reaction of a polyhydric phenol with
a carbonate precursor: sae for exa~ple U.S. Patent
3,989,672. Although such polycarbonate resins have
been found to be thermoplastically moldable under a
broad range of molding conditions, only select
polycarbonate resin co~positions ar~ cuitable for
blow-molding. Thi~ is due to the unique
requirements of a ther~oplastic resin for blow-
molding operatio~.
In the conventional blow-molding operation, a
tube of the heat-softsned polycarbonate resin may be
extruded vertically into a mold. The extrudate is
then pressed unto ths ~old ~urfaces with a
pressurized gas fl~w (usually air or inert gas),
shaping the heat-softened resin. As appreciated by
~hose skilled in the art, the successful molding of
a given thermoplastic resin is dependent upon a
number of factors, including the characteristics and
physical propertie~ o~ the heat-softened resin.
Among so~tened resin properties to be con~idered are
the melt vi~cosity and the ~elt strength of the
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8CL-6838
resin. These two factors alone are of consider~le
importance in the successful blow-moldina _l any
resin, particularly in regard to t~- molding of
large articles.
Many aromatic pOly~arbonate resins are eminently
useful in blOw-m~laing operations because they meet
the nec~s~ry requirements of melt viscosity, melt
strength and other desirable physical properties.
Branched polycarbonate resins such as those
described in the U.S. Patents 4,101,184 and
4,474,999 are particularly useful ~or blow-molding,
having many o~ the desirable physical properties.
However, blow-molding the branched polycarbonate
resin compositions has not been completely
- satisfactory in all respects. In particular, many
of the prior art compositions may have an inherent
lack of a relatively high melt strength coupled with
a relatively low melt viscosity. Resin additiv~s
are known, such as amine types of aliphatic esters,
which when admixed with many branched polycarbonate
resins will lower the melt viscosity of the
composition. ~owever, the additives generally
degrade polycarbonate resin, and the molded articles
consequently exhibit lowered impact strength.
We have found that blow moldable polycarbonate
resin compositions containing a thermoplastic
copolymer of a styrenic monomer and an acrylonitrlle
monomer in addition to a conventional impact
modifier, can be blow-molded to obtain articles
exhibiting high impact strength. Most importantly
the compositions possess a high melt strength, but
also respond to shear-thinning, i.e.; under thermo-
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8CL--6838
processing conditions they exhibi~ low meltviscosities.
The improved processability is obtained without
a significant loss of other properties in thC molded
articles prepared from the compositio~o of the
invention. In ~act, in some instances the property
of impact strength may sho~ improvement.
SUMMARY OF THE INVENrION
The invention comprises blow-molding resin
compositions, which comprise;
a blow-moldable, branched polycarbonate resin;
a processability-modifying proportion of a
copolymer of a styrenic monomer and an acrylonitrile
monomer: and
an impact-modifying proportion of a
polycarbonate impact modifier.
The invention also comprises articles blow-
molded from compositions of the invention. The
articles of the invention are useful as bottles,
tool housings, automotive components and the like.
DETAILED DESCRIPTION OF THE PREF2RRED
EMBODIMENTS OF THE INVENTION
Blow Moldable, branched polycarbonate (PC)
resins are generally well known and may be prepared
by reacting a dihydric phenol and a polyfunctional
organic compound with a~carbonate precursor, such as
phosgene, a haloformate or a carbonate ester.
Generally speaking, such carbonate polymers may be
typified as possessing recurring structural units of
the formula:
~ O - D - O - C 3
(I)
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~3 ~.1 !3 J
8CL-6838
wherein D i~ a divalent aromatic radical, residue of
the dihydric phenol employed in the polymerization
reaction. Occasional branch moieties occur als~ in
the polymer chain bearing residues of the
polyfunctional organic compound. The ~ethod of
preparation is well known; see for example the
inter~acial polymerization met~od described in U.S.
Patents 4,001,18~ and ~,474,999, both of which are
herein incorporated by reference.
In general, the method of interfacial
polymerization comprises the reaction o~ the
dihydric phenol with a carbonyl halide (the
carbonate precursor~ and the polyfunctional organic
compound.
Although the reaction conditions of the
preparative processes may vary, several o~ the
preferred processes typically involve dissolving or
dispersing the dihydric phenol and polyfunctional
organic compound reactants in aqueous caustic,
adding the resulting mixture to a suitable water
immiscible solvent medium and contacting the
reactants with the carbonate precursor, such as
phosgene, in the presence of a suitable catalyst and
under controlled pH conditions. The most commonly
used water immiscible solvents include methylene
chloride, 1,2-dichloroethane, chlorobenzene,
toluene, and the lik~.
The catalyst employed accelerates the rate of
polymerization of the dihydric phenol reactant with
the carbonate precursor. Representative catalysts
include but are not limited to tertiary amines such
as triethylamine, quaternary phosphonium compounds,
guaternary ammonium compounds, and the like. The
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8CL-6838
preferrod process ~or Pre~aring polycarbonate resins
used in the invention comprises a phosgenation
reaction. The temperature at which the phosa~ n
reaction proceeds may vary from belo~ o C, to above
100C. The phosgenation reaction preferably
proceeds at temperatur~ of from room temperatures
(25C) to 50C. slnce the reaction is exothermic,
the rate of phosgene addition may be used to control
the reaction temperature. The amount of phosgene
required will generally depend upon the amount of
the dihydric phenol and the amount of polyfunctional
organic compound present.
The dihydric phenols employed are known, and
the reactive groups are the two phenolic hydroxyl
groups. Some of the dihydric phenols are
represented by the general fo~mula:
~ (X)4 ~ ~X)
H0 ~ A ~
(II)
wherein A is a divalent hydrocarbon radical
containing from l to about 15 carbon atoms; a
substituted divalent hydrocarbon radical containing
from l to about 15 carbon atoms and substituent
groups such as halogen;
-S- ; -S-S- ; -S(=0)- ; -S(=0)2- ; -0- : or -C(-0)- ;
wherain each X is independently selected from the
group consisting of hydrogen, halogen, and a
monovalent hydrocarbon radical such as an alkyl
group of ~rom l to about 8 carbon atoms, an aryl
group of from 6-l8 carbon atoms, an aralkyl group of
from 7 to about 14 carbon atoms, an alkaryl group of
from 7 to about 14 carbon atom~, an alkoxy group of
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8CL-~838
from 1 to about 8 carbon ato~s, or an aryloxy group
of from 6 to 18 carbon atoms; and wherein m is zero
or 1 and n is an integer of from 0 to 5.
Typical of some of the dihydric phenols that
can be employed in the practice of the present
invention are bis-phenols such as (4-hydroxy-
phenyl)methane, 2,2-bis(4-hydroxyphenyl)propane
(also known as bisphenol-A), 2,2 bis(4-hydroxy-3,5-
dibromophenyl)propane; dihydric phenol ethers such
as bis(4-hydroxyphenyl) ether, bis(3,5-dichloro-4-
hydroxyphenyl) ether; dihydroxydiphenyls such as
p,p' dihydroxydiphenyl, 3,3'-dichloro-4,4'-
dihydroxydiphenyl; dihydroxyaryl sulfones such as
bis(4-hydroxyphenyl) sulfone, bis (3,5-dimethyl-4-
hydroxyphenyl) sulfone~ dihydroxybenzenes such as
- resorcinol, hydroquinone, halo- and alkyl-
substituted dihydroxybenzenes such as 1,4-dihydroxy-
2,5-dichlorobenzene, 1,4-dihydroxy-3-methylbenzene;
and dihydroxydiphenyl sul~ides and sulfoxides such
as bis(4-hydro~yphQnyl) sul~ide, bis(4-hydroxy-
phenyl) sulfoxide and bis~3,5-dibromo-4-hydroxy-
phenyl) sulfoxide. A variety of additional dihydric
phenols ar~ available and are disclosed in U.S. Pat.
Nos. 2,g99,835; 3,028,365 and 3,153,008; all of
which are incorporated herein by reference. It is,
of course, possible to ~ploy two or more dif~erent
dihydric phenols or a combination of a dihydric
phenol with glycol~
The carbonate precursor can be either a
30 carbonyl halide, a diarylcarbonate or a bishalo-- -
formate. The carbonyl halides include carbonyl
bromide, carbonyl chloride, and mixtures thereof.
The bishaloformates include the bishaloformates of
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8CL-6838
dihydric phenols ~uch as bischloroformates of 2,2-
bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3,5-
dichlorophenyl)propane, hydroquinone, and th~ like,
or bishaloformates o~ glycols such as bishalo-
formates of ethylene glycol, and the like. Whileall of the above carbonate precursors are useful,
carbonyl chloride, also known as phosgene, is
preferred.
Branching results ~rom th~ inclusion of the
polyfunctional organic compound, which is a
branching agent. The polyfunctional organic
compounds are generally well Xnown, aromatic and
contain at least three functional groups which are
carboxyl, carboxylic anhydrides, phenol~,
haloformyls or mixtures thereof. Some nonlimiting
examples of these polyfunctional aromatic compounds
include l,l,l-tri(4-hydroxyphenyl) ethane,
trimellitic anhydride, trimellitic acid,
trimellitoyl trichloride, 4-chloroformyl phthalic
anhydride, pyromellitic acid, pyromellitic
dianhydride, mellitic acid, mellitic anhydride,
trimesic acid, benzophenonetetracarboxylic acid,
benzophenonetetracarboxylic anhydride, and the like.
The preferred polyfunctional aromatic compounds are
~5 l,l,l-tri~4-hydroxyphenyl)ethane, trimellitic
anhydride or trimellitic acid or their haloformyl
derivatives.
Also included herein are blends of a linear
polycarbonate and a branchad polycarbonate.
The aromatic carbonate branched polymers for
use as a component of the compositions of the
invention include polyester-carbonates, also known
a copolyester-polycarbonates, i.e., resin~ which
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8CL-6838
contain, in addition to recurring polycarbonate
chain units oP the formula (I), given above,
repeating or recurring carboxylate units, for
example of the ~ormula:
~ O-C(=O)-R1-C(-O)-O D~
wherein D is as defined above a~d Rl~s as defined
below.
In general ~he copolyester-polycarbonate resins
are prepared as d~cribed above for the preparation
of polycarbon~te homopolymers, but by the added
presence o~ a dicarboxylic acid (ester precursor) in
the water immiscible solvent.
In general, any dicarboxylic acid convention-
ally used in the preparation of linear polyesters
may be utilized in the preparation of the
copolyester-carbonate resins of the instant
invention. Generally, the dicarboxylic acids which
may be utilized include the aliphatic dicarboxylic
acids, the aromatic dicarboxylic acids, and the
2Q aliphatic-aro~atic dicarboxylic acids. These acids
are well known and are disclosed for example in U.S.
Pat. No. 3,169,121 which is hereby incorporated
herein by reference. Representative of such
aromatia dicarboxylic acids are those represented by
the general formula:
HOOC-RI-COOH
(IV)
wherein Rl represents an aromatic r~dical such as
phenylene, naph$hylene, biphenylene, substituted
phenylene and the like; a divalent aliphatic-
aromatic hydrocar~on radical such as an aralkyl or
alkaryl radical; or two or more aromatic groups
~;J ~ _i i .~ ~ i
8CL-6838
connected through non-aromatic linkages of the
formula:
- E -
wharein E is a dival~nt alkylene or alkylidene
group. E may also consist o~ two or more alkylene
or alkylidene groups, connected by a non-alkylene or
alkylidene group, connected by a non-alkylene or
non-alkylidene group, such a~ an aromatic linkage, a
tertiary amino linkage, an ether linkage, a carbonyl
linkage, a silicon-containing linkage, or by a
sulfur-containing linkage such as sulfide,
sulfoxide, sul~one and the like. In addition, E may
be a cycloaliphatic group o~ five to seven carbon
atoms, inclusive, ~e.g. cyclopentyl, cyclohexyl), or
a cycloalkylidene of five to sev~n carbon atoms,
inclusive, such as cyclohexylidene. E may al o be a
carbon-free sulfur-containing linkage, such as
sulfide, sulfoxide or ~ul~one; an ether linkage; a
carbonyl group; a direct bond; a tertiary nitrogen
group; or a silicon-containing linkage such as
silane or siloxy. Other groups which E may
represent will occur to those skilled in the art.
For purposes of th~ present invention, the aromatic
dicarboxylic acids ara preferred. Thus, in the
preferred aro~atic difunctional carboxylic acids, R
is an aromatic radical such as phenylene,
biphenylene, naphthylene, or substituted phenylene.
Some non-limiting examples of ~uitable aromatic
dicarboxylic acids which may be used in preparing
the poly(ester-Carbonate) or polyarylate resins o~
the instant invention include phthalic acid,
isophthalic acid, terephthalic acid, homophthalic
acid, o-~ m-, and p-phenylenediacetic acid, and the
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8CL-6838
polynuclear aromatic acids such as diphenyl
dicarboxylic acid, and isomeric naphthalene
dicarboxylic acids. The aromatics may be
substituted with Y groups. Y may be an inorganic
atom such as chlorine, bromine, fluorine and the
like; an oxganic group such as the nitro group; an
organic group such as alkyl; or an oxy group such as
alkoxy, it being only necessary that Y be inert to
and unaffected by the reactants and the reaction
conditions. Particularly use~ul aromatic
dicarboxylic acids are those represented by the
general formula: -
(R3)
HOOC ~
~ ~ COOH
(V)wherein j is a positive whole integer having a value
of from 0 to 4 inclusive; and each R3 is
independently selected from the group consisting of
alkyl radicals, preferably lower alkyl (1 to about 6
carbon atoms).
Mixtures of these dicarboxylic acids may be
employed. Therefore, where the term dicarboxylic
acid is used herein it is to be understood that this
term includes mixtures of two or more dicarboxylic
acids.
Most preferred as aromatic dicarboxylic acids
are isophthalic acid, terephthalic acids, and
mixtures thereof. A particularly useful
difunctional carboxylic acid comprises a mixture of
isophthalic acid and terephthalic acid wherein the
weight ratio of terephthalic acid to isophthalic
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8CL-6838
acid is in the range of from about 10:1 to about
002:9.8.
Rather than utilizing the dicarboxylic acid per
se, it is possible, and sometimes even preferred, to
employ the reactive derivatives of said acid.
Illustrative of these reactive derivatives are the
acid halides. The preferred acid halides are the
acid dichlorides and the acid dibromides. Thus, for
example instead of using isophthalic acid,
texephthalic acid or mixtures thereof, it is
possible to employ isophthaloyl dichlori~e,
terephthaloyl dichloride, and mixtures thereo~.
The proportions of reactants employed to
prepare the copolyester-carbonate resins of the
invention will vary in accordance with the proposed
use of the product resin. Those sXilled in the art
are aware of useful proportions, as described in the
U.S. patents referred to above. In general, the
amount of the ester bonds may be from about 5 to
about 90 mole percent, relative to the carbonate
bonds. For example, 5 moles of bisphenol A reacting
completely with 4 moles of isophthaloyl dichloride
and 1 mole of phosgene would give a copolyester-
carbonate of 80 mole percent ester bonds.
The preferred branched polycarbonates for use
in the present invention are those derived from
bisphenol A and phosgene and having an intrinsic
viscosity of 0.3 to 0.75 deciliters per gram,
measured in methylene chloride at 25 C.
In general, blow-moldable polycarbonate basPd
resins will have an R* value within the ranqe of
from about 1.4 to about 10Ø Relatively small
moldings are advantageously blow-molded from resins
having an R* value below about 4.3 while larger
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8CL-6838
moldings (on the order of about 4-20 Kg) will have
R* values above 5Ø The R* value is an indication
of blow~moldability of a composition and may be
calculated as follows:
STEP 1 - Generate viscosity (~ and
elastic modulus (G') da~a on test compositions at
three tempera~ures, with a rotational rheometer such
as the RD5 7000, (Rheometrics Inc.).
STEP 2 - Using the data ~rom STEP 1 fitted
to the Arrhenius type equations, calculate optimum
melt temperature for parison extrusion ti.e., the
temperature required to yield a malt viscosity of
20,000 poise at 100 sec~l).
STEP 3 - Calculats the ratio of viscosity
at low shear rate (1 sec 1 nominal) to viscosity at
100 sec 1 ~20,000 poise), R*, at temperature
estimated in STEP 2. Elastic modulus values (@ 1
sec 1) are also calculated at this temperature.
The copolymer of styrenic monomer and an
acrylonitrile monomer is added to the polycarbonate
in a processability-modifying proportion.
The term "processability-modifying proportion"
as used herein means a proportion of the processing
modifier sufficient to enhance the shear-thinning
property of the polycarbonate, when melted. In
general, such a proportion is within the range of
from about 5 to about 30 parts by weight of the
total molding composition polymers.
In accordance with the present invention, a
copolymer of a styrenic monomer and an acrylonitrile
monomer employed as components of resin blends o~
the invention include those sometimes referred to in
the art as "SAN types of polymers"~ Th~ "SAN types
of Polymers" are a wide variety of polymPrs, the
molecules of which contain two or more monomeric
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8CL-6~33~
parts that are copolymerized. One monomer or group
of monomers that may be co-polymerized and referred
to above as styrene types of monomer are
monovinylaromatic hydrocarbons. The
monovinylaromatic monomers may be generically
described by the formula:
X X
X ~/~--C C~
X ~ X
(VI)
wherein each X is independently selected from the
group consisting of hydrogen, alkyl of 1-5 carbon
atoms, chlorine or bromine. Examples of the
monovinylaromatic compounds and alkyl-, cycloalkyl-,
aryl-, alkaryl-, aralkyl-, alkoxy-, aryloxy-, and
other substituted vinylaromatic compounds include
styrene, 4-methyl- styrene; 3,5-diethylstyrene, 4-n-
propylstyrene, ~-methylstyrene; ~-methyl-
vinyltoluene, ~-chlorostyrene, ~-bromostyrene,
dichlorostyrene, dibromostyrene, tetra-
chlorostyrene, mixtures thereof, and the like. Thepreferred monovinyl- aromatic hydrocarbons used are
styrene and/or ~-methylstyrene and p-methylstyrene.
The second group of monomers, i.e.; the
acrylonitrile type that may be polymerized in
preparing the SAN type of copolymer are acrylic
monomers such as acrylonitrile and substituted
acrylonitrile. Minor amounts of acrylic acid
esters, or methyl acrylic esters exemplified by
alkyl acrylates such as methyl methacrylate may be
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8CL-6838
1~
present during the polymerization of the SAN type of
copolymers used hersin.
The acrylonitrile and substituted
acrylonitriles, are described generically by the
fo~mula:
X
~ C = C CN
(VII)
wherein X i5 as previously definedO Examples of
such monomers include ethacrylonitrile,
methacrylonitrile, ~-chloroacrylonitrile, ~-
chloroacrylonitrile, ~-bromoacrylonitrile, and ~-
bromoacrylonitrile.
The most preferred SAN copolymers employed in
the ~lends of the invention contain 20-35 percent
acrylonitrile segments (by weight) and 80-65%
styrene or alkyl-substituted styrene or mixtures
thereof, segments (by weight)~
It is advantageous that the compositions of the
invention include an impact-modifying proportion of
an impact modifier. Any o~ the known polycarbonate
impact modi$iers may be used. Representative of
such impact-modifiers are selectively hydrogenated
linear, sequential or ~adial teleblock copolymers o~
a vinyl aromatic compound ~A) and (A') n and an
olefinic elastomer (B) o~ the A-B-A~: A (B-A-B )nA; A
( B-A )n~; or B [( A-~) B]4 type wherein n is an
integer of from 1 to 10 inclusive.
The selectively hydrogenated line r block
copolymers are well known as are methods of their
preparation, and they are commercially available.
The selectively hydrogenated lineax block copolymers
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8CL-G838
are well known and are describad by Hae~ele et al,
U.S. Pat. No. 3,333,024, which is incorporated
herein by reference.
Prior to hydrogenation, the end blocks of these
copolymers comprise homopolymers or copolymers
preferably prepared from alkenyl aromatic
hydrocarbons and particularly vinyl aromatic
hydrocarbons wherein the aromatic moiety may be
either mono~yclic or polycyclic. Typical monomers
include styrene, alpha methyl styrene, vinyl xylene,
ethyl vinyl ~ylene, vinyl naphthalene, and the like,
or mixtures thereo~ The end block (A) ~nd (Al), may
be the same or dif~erent. They are preferably
selected from styrene, ~-m~thyl styrene, vinyl
toluene, vinyl xylene, vinyl naphthalene, especially
styrene. The center block (B) may be derived ~rom,
for example, butadiene, i~oprene, 1,3-pentadiene,
2,3,dimethyl butadiene, and the like, and it may
havs a linear, se~uential or teleradial structure.
The ratio of the copolymers and the average
molecular veights can vary broadly although the
molecular weight center block should be greater than
that of the co~bined terminal blocks. It is
preferred to form terminal blocks A having weight
average molecular weight~ of 2,000 to 100,000 and
center block B, e.g., a hydrogenated polybutadiene
block with a wei~ht average molecular weight of
25,000 to 1,000,000. 5till more prefera~ly, the
terminal blocks may have weight average molecular
weights of 8,000 to 60,000 while the hydrogenated
polybutadiene polymer blocks have a weight av~rage
molecular weight between 50,000 and 300lO00. The
terminal blocks will pre~erably comprise 2 to 60~ by
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8 CL- 6 8 3 8
16
weight, or more, preferably, 15 to 40~ by weight, of
the total block co-polymer. The preferred
copolymers will be those formed from a copolymer
having a hydrogenated/ saturated polybutadiene
S center block wherein 5 to 55%, or more, preferably,
30 to 50% of the butadiene carbon atoms, are vinyl
side chains.
The hydrogenated copolymers will have the
average unsaturation reduc d to less than 20% of the
original value. It is preferred to have the
unsaturation o~ the center block B reduced to 10%,
or less, preferably 5% of its original value.
The block copolymers are formed by techniques
well known to those skilled in the art.
Hydrogenation may be conducted utilizing a variety
of hydrogenation catalysts such as nickel on
kieselguhr, Raney nickel, copper chromate,
molybdenum sulfide and finely divided platinum or
other noble metals on a low surface area carrier.
Hydrogenation may be ~onducted at any desired
temperature or pressure, from atmospheric to 300
psig, the usual range being between 100 and 1,000
psig at temperatures from 75 F. to 600 F. for times
betwQen 0.1 and 2~ hours, preferably from 0.2 to 8
hours.
Hydrogenated block copolymers such as Kraton~ G-
6500, Kraton~ G-6521, Kratone G-1650 and Kraton~ &-
1652 are available from Shell Chemical Company,
Polymers Division. Kraton~ G-1550 and Kraton~ G-
1651 are preferred for use in the compositions ofthe invention. Also usable are the so-called
hydrogenated Solprenes of Phillips Petroleum Co.,
especially the product designated Solprene0-512.
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8CL--6838
The radial teleblock copolymers, of which the
Solprenes are typical examples, ca~ be characterized
as having at least three polymer bxanches with each
branch of the radial block polymer comprising
texminal non~elastomeric segments, e.g. ~A) and (Al )
as defined hereinaboveO The branches of the radial
block polymer contain a terminal non-elastomeric
segment attached to an elastomeric polymer segment,
e.g. (B) as defined above. These are described by
Marrs, U.S. Pat. No. 3,753,936 and by æelinski~ U.S.
Pat. No. 3,281,383, both o~ which are incorporated
herein by refer2nce, and they are selectivPly
hydrogenated by procedures as described above. In
any event, the term "selective hydrogenation" is
usPd herein to contemplate polymers in which the
elastomeric blocks (B) have been hydrogenated, but
the non-elastomeric blocks (A) and (A1) have been
left unhydrogenated, i.e., aromatic.
The selectively hydrogenated copol~er is used
in a proportion of from about 1 to 4 parts by weight
(prefarably 2 parts by weight for each 100 parts of
polycarbonate resin.
Preferred as the impact-modifier used in the
compositions o~ the invention are the so-called
"ABS" polymers. ABS polymers are defined, for
example, in the Modern Plastics Encyclopedia, 19~9
edition, page 92, as the family of thermoplastics
made from the three monvmers acrylonitrile,
butadiene and styrene, and more speci~ically as a
mixture (alloy) o~ ~tyrene-acrylonitrile copolymer
with SAN-gra~ted polybutadiene rubber.
The preferred ABS polymer of high rubber content
for use as an impact-modifier i5 an ABS having
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8CL-6838
1~
greater than 32% rubber content and made by emulsion
polymerization, rather than ~y bulk or suspension
polymerization which are processes ~requently used
to manufacture commercial ABS; an ABS made by
5 emulsion polymerization is U.S. Pat. 2,820,773
(1958) which is incorporated by reference. ABS
resins made by emulsion polymerization and having
high rubber content are commercially available, for
example the following:
Novalar made by ~ova Polymers, Inc.: a powdered ABS
having about 41% butadiene rubber content, a density
of 1.04 and a melt flow index of 4.0; and
Blendex 301 made by General Electric Company: a
powdered ABS having about 34~ polybutadien rubber
15 content, a specific gravity of 0.99 by ASTM D-792
Method A-l, and a heat deflection temperature of
172 F at 10 mil deflection and 264 psi (annealed) by
ASTM D-648.
Impact - modifying agents for use with the
polycarbonate compositions of the invention also
include the various polyacrylate resins known in the
art. For example, suitable polyacrylates can be
made in known ways, but are abundantly commercially
available from many sources, e.g., Rohm & Haas
Chemical Company, Philadelphia, Pa. under the trade
designations Acryloid~ KM 330, and 7709 XP; Goodyear
Tire & Rubber Company, Akron, Ohio under the trade
designation RXL~ 6886; from American Cyanamid
Company, Stamford, CT., ùnder the trade designation
CyanacrylX 770; from M&T Chemicals Co., Trenton, NJ,
under the trade designation Durostrength~ 200: and
from Polysar Corporation, Canada, under the trade
designation Polysar~ 100S. In general any of the
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8CL-6838
19
polyalkyl acrylates described by Brinkman et al.,
U.S. Pat. No. 3,591,659 can be used, especially
those containing units derived from n-butyl
acrylate. Preferably, the polyacrylate will
comprise a multiple stage polymer having a rubbery
first stage and a thermoplastic hard final stage as
described in Farnham et al., U.S. Pat. No. 4,096,202
incorporated herein by reference. It has also been
found advantageous to add both polyalky acrylate and
an acrylate-based core-shell polymer such as
Acryloid~ KM-330, above-mentioned.
The polyacrylate resin impact modifiers may be
added to the compositions of the invention in
conventional amounts of from 0.01% to 50% by weight
based on the weight of the overall composition and
usually in amounts of from 0.01% to 10% by weight on
the same basis.
Another class of known polycarbonate impact
modifiers which may be used as an ingredient of the
resin compositions of the invention are polyamide-
polyether block copolymers which may be represented
by the schematic formula: -
~O O
HO- - ~ - PA - ~ - O - PE - O- - H
n
(IX)
wherein PA represents the polyamide segment, PE
represents a polyether segment and n is an integer
such that the block copolymer has a weight average
molecular weight (~) of from about 5,000 to about
100,000. Polyamide-polyether bloc~ copolymers of
the class described above are generally well known
and may be prepared for example by the condensation
., :-, ~ . :
,:
~ 3
8CL 6838
reaction of a prepolyamide and a polyoxyalkylene
glycol, by conventional technique; see for example
the preparative methods described in U.S. Patents
4,20~,493; 4,230,838: 4,361,680: and 4,331,786, all
of which are incorporated herein by reference
thereto. The polyamide - polyether block copolymers
so prepared are commercially available and may be
wide ranging in their make-up from a wide range of
prepolyamides and polyoxyalkyiene glycols.
The prepolyamide may have an inherent viscosity
of at least about 0.1 (determined at a temperature
of 25~C. using o.25 ~m of polymer per 100 ml. of a
solvent consisting of 60 percent phenol and 40
percent by volume of tetrachloroethane) and will be
terminated with acid or amine groups. The
prepolyamide may be the polymerization product of a
difunctional diamine component and a difunctional
dicarboxylic acid.
In general, any aliphatic, alicyclic, and
aromatic difunctional diamine or mixture ot diamines
can be used to prepare the prepolyamide. Examples
of such diamines include polymethylenediamines of
the formula H2N (CH2~XNH2, wherein x is a positive
integar of ~rom 2 to 12 (such as dimethylenediamine,
trimethylenediamine, tetramethylenediamine,
pentamethylenediamine, hexamethylenediamine,
heptamethylenediamine, octamethylenediamine,
nonamethylenediamine, decamethylenediamine,
undecamethylenediamine, and dodecamethylenediamine);
1,1-, 1,2-, 1,3-, and 1,4- cyclohexane-bis-
(methylamines); o-, m-, and p-xylenediamines; l,2-,
1,3- and 1,4-cyclohexanediamines; 3-methylhexa-
methylenediamine; 3-methylheptamethyenediamine;
`, , ~ ~ . '' ' . "' . ' ' '
- .
8CL-6838
2,4-dimethylhexamethylenediamine;
2,4-toluenediamine; p,p'-diphenydiamine;
1,4-dimethyl 3,5-diaminobenezene;
2,5-norcamphane-bis-(methylamine); o-, m-, and
p-phenylenediamines; 2,5-,2,6-, and
2,7-naphthalenediamines; benzidine;
4,4'-methylenedianiline; and 3,4'-diaminodiphenyl.
The N,N'-diphenyldiamines of U.S. Pat. 3,297,656 can
also be employed.
In general, any aliphatic, alicyclic, and
aromatic difunctional dicarboxylic acid can be used
to prepare the prepolyamide. Examples of such acids
include oxalic; malonic; dimethylmalonic; succinic;
glutaric; adipic; trimethyladipic; pimelic;
2,2-dimethylglutaric; azelaic; sebacic; suberic;
fumaric; maleic, itaconic;
1,3-cyclopentanedicarboxylic:
1,2-cyclohexanedicarboxylic;
1,3-cyclohexanedicarboxylic;
1,4-cyclohexanedicarboxylic; phthalic; terephthalic;
isophthalic; t-butyl isophthalic;
2,5-norbornanedicarboxylic~
1,4-naphthalenedicarboxylic; diphenic;
4,4'-oxydiben~oic; diglycolic; thiodipropionic;
2,2,4-trimethyladipic; 4,4'-sulfonyldibenzoic;
2,5 naphthalenedicarboxylic;
2,6-naphthalenedicarboxylic; and
2,7-naphthalenedicarboxylic acids.
The prepolyamides are prepared by conventional
and known techniques for the preparation of a
polyamide resin and may have a weight average
molecular weight of from 300 to 15,000.
.
.
- :
.
: - .
8CL-6838
The polyoxyalkylene glycols used to prepare the
polyamidepolyether block copolymers used as
impact-modifiers in the pre~ent invention are well
known compounds and include for example
polyoxypropylene glycol, polyoxyethylene glycol and
polyoxybutylene glycol, each of which are
commercially available and have weight average
molecular weights (~) of from 200 to 15,000. The
preferred polyoxyalkylene glycols may also be
charactexized by an inherent viscosity of from 0.1
to 0.5 (determined a~ described above for the
determination of inharent viscosity of the
prepolyamide). The polyether can have diol and/or
diamine end groups, amino end groups can be prepared
through cyanoethylation of the polyether followed by
hydrogenation. Other modifications of the polyether
end groups can also be made to facilitate bonding to
the polyamide blocks.
The preferred impact-modifying
polyamide-polyether block copolymer employed in the
compositions and the method of the invention are of
the formula (IX) given above, wherein PA represen~s
a saturated amide sequence formed from a lactam or
an amino acid having a hydrocarbon chain containing
from 4 to 14 carbon atoms, inclusive, or from a
diamine and a dicarboxylic acide each having from 4
to 40 carbon atoms, inclusive; said amide having a
weight average molecular weight of from 300 to
15,000; and PE represents a polyether sequence
formed from a polyoxyalkylene glycol having a weight
of ~rom 200 to 15,000. Most preferred, the copolymer
will be one wherein the proportion by weight of
polyoxyalkylene glycol with respect to the total
. . , ~
8CL-6838
weight of the copolymer is from 5 to 85 percent. In
general, these preferred block copolymers will have
an intrinsic viscosity of from 0.8 to 2.05 as
measured in meta-cresol at 25 C. (initial
concentration: 0.8 gms/100 ml).
The polyamide-polyether impact-modifying
copolymer can be present in a wide range of
concentrations. However, to obtain the most useful
blends, it is preferable to maintain the
concentration of impact-modifying copolymer to less
than 40% by weight of the total composition of the
invention. Concentrations of from 2 to 30 weight
percent of impact-modifying copolymer provide a
significant enhancement in impact strength without a
significant enhancement in impact strength without a
significant loss to other desirable physical
properties of the blend, such as heat distortion
temperature. Concentrations bPlow 5% by weight can
be expected tohave an enhancing ~ffect on impact
strength but atlevels which correspond to the low
concentration. The most preferred concentrations
fall within the highest impact modifying e~ect
varying with the ratio of polycarbonate to
polyamide, as discuss~d above.
Other representative impact modifiers are the
synthetic polymeric resin elastomers such as
silicone rubber, polyether rubber and ethylene-
propylene-diene rubber; diene rubbers, i.e.,
homopolymers of conjugated dienes having, e.g. 4 to
8 carbon atoms, such as butadiene, isoprene,
norbornene, piperylene and chloroprene: and
copolymers of dienes such as ethylene with each
other or with styrene, acrylic acid, methacrylic
, :
: . ' ' `, `
-
:
:
. .
8 CL- 6 8 3 8
24
acid, or derivatives thereof (e.g., acrylonitrile,
methacrylo-nitrile, acrylic acid, methacrylic acid,
butyl acrylate and methyl methacrylate), or
isobutylene.
An impact-modifying proportion of the latter
impact modifers described above is generally within
the range of from about 0.05 to 15 parts by weight
of the composition, preferably from 3-10 parts, most
preferably 4 to 8 parts.
Other impact-modifying agents useful in the
compositions of the invention will be appreciated by
those skilled in the art.
It will be appreciated by those skilled in the
art that an impact modifying proportion of the
lS impact modifier used in the compositions of the
invention will be dependent upon the particular
modifier selected. In general however, the
proportion will be most preferably one within the
range of from about 5 to about 20 parts by weight of
the polycarbonate.
The compositions of the invention may be
prepared by homogeneously blending with the
polycarbonate the copolymer of the styrene-
acrylonitrile and the impact modifier described
above. The blending may be carried out by use of
conventional and known techniques and apparatus for
the blending together of synthetic polymeric resin
components. In general, the mixtures of components
may be blanded by pre-mixing in conventional mixing
rolls, dough mixers, Banbury mixers and the like and
by blending the pre-mix in an extruder or fluxing it
on a mill at an elevated temperature sufficient to
achieve a homogeneous blending. Upon cooling, the
-- , , : : .
~ S ~ ~..q ~
8CL-6838
blend may be palletized and stored for molding into
articles.
The thermoplastic blend o~ the invention may
also be compounded with conventional ~olding aids
such as, for example, antioxidant~; antistatic
agents; inert fillers such as glass, talc, mica, and
clay; ultraviolet radiation absorbers such as the
benzophenones, benzotriazoles, and the like:
hydrolytic stabilizers such as the epoxides
disclosed in U.S. Pats. Nos. 3,489,716, 4,138,379
and 3,839,247, all of which are incorporated herein
by reference: color stabilizers such as the
organophosphites; thermal stabilizers such as
phosphite; mold release agents and ~lame retardants.
Some particularly useful flame retardants are the
alkali and alkaline earth metal salts of sulfonic
acids. TheRe type~ of flame retardants are
disclosed in U.S. Pats. Nos. 3,933,734; 3,931,100;
3,978,~24; 3,948,851; 3,926,980; 3,919,167;
3,909,490; 3,953,396; 3~953/300; 3,917,559;
3,951,910 and 3,940,366, all o~ which are hereby
incoxporated herein by reference.
The following examples describe the manner and
proce~s of making and using the invention and set
forth the ~est mode contemplated by ths inventor ~or
carrying out the invention but are not to be
construed as limiting the scop~ of the invention.
All parts are by w~ightO Test results are in
accordance with the following test m~thode.
Inkrinsic Viscosity:
The intrinsic YisCOsity O~ polycarbonates was
measured at a temperature of 25C in methyl~ne
chloride and i8 reported in deciliters/gram (de/g).
.- ,
. , ~ . .
': ,
,~
8CL-6838
26
Tensile Stren~ths and Elonqation
ASTM Test Method D-638.
Flexural Yield and Modulus
ASTM Test Method D-790.
Notched Izod Impact Strength:
ASTM Test Method D~256; all specimens were 100%
ductile at failure, unless otherwise noted.
Melt Flow:
ASTM Test Method D-1232.
Weld Line Strenath:
ASTM Test ~ethod D-256.
R*:
R* may be calculated as follows:
STEP 1 - Generate viscosity (~*) and
elastic modulus (G') data on test compositions at
three temperatures, with a rotational rheometer such
as the RDS 7000, (Rheometrics Inc.).
STEP 2 - Using the data from STEP 1 fitted
to the Arrhenius type equations, calculate optimum
melt temperature for parison extrusion (i.e., the
temperature required to yield a melt viscosity of
20,000 poise at 100 sec~l).
STEP 3 - Calculate the ratio of viscosity
at low shear rate (1 sec 1 nominal) to viscosity at
100 sec 1 (20,000 polse), R*, at temperature
estimatad in STEP 2. Elastic modulus ~alues (@ 1
sec 1) are also calculated at this temperature.
Exa~ple 1:
Sixty-five parts by weight of a branched poly-
carbonate prepared according to the method described
in U.S. Patent No. 4,101,184 and having an intrinsic
viscosity of from about 0.5 to about 0.65
deciliters/gram dl/g) as determined in a methylene
chloride solution at a temperature o~ 25 C (LEXAN9
,
. -
:
' : ' '
8CL-6838
155, General Electric Co.) is mixed with 25 parts of
Blendex~ 580 SAN, General Electric Co., (a SAN
copolymer of styrene and acrylonitrile with a SAN
ratio of ~2:28) and 10 parts of Blendex~ 338,
Gen~ral Electric Co., supra. (a powdered ABS, made
by emulsion polymerization). The mixture is
uniformly blended together in a laboratory tumbler
and the blend then introduced into a melt extruder.
The extrudate is pelletized and the pellets are fed
to an injection molding machine to mold test ~ars of
5.715 cm x 1.27cnwith a thickness of 3.175mm. The
moldings are subjected to tests to determine their
blow-moldability and physical properties. The test
results are given in the Table, below.
Examples a- 4:
The procedure of Example 1, supra., is repeated
except that the proportions of the ingredients are
modified. The proportions of ingredients and test
results are given in the Table below.
Example 5 (Comparative Example!
The procedure of Exam~les 2-4, supra. is
repeated except that the weight proportion of ABS
resin as used therein is replaced by an equal
proportion of additional Lexan ~ 155 polycarbonate
resin. The test results are shown in the Table,
below.
All af the resin compositions prepared in
accordance with the Examples 1-4, supra., are
readily blow molded into articles such as bottles
and automotive parts having large dimensions and
exhibiting the same physical properties assigned to
the resin compositions from which they are molded.
..
- ' .
~ ,
, ~ ; ,, :
;.
.:
8CL-6838
28
.~
~ 1~1 O O I t~r~ H lo N Ir)
00 N I ~1 ~ N ~ -
~3 1~ ~
V
~r o o ou~ ~ 1 ~ ~`
CO _I ~1 ~ O ~ ~
t~
~¦ O U) LnN O ~7
~4 U)
O O O~ O O CO
~ ~ ~ D O ~
~1
E~ ~1 U) ~ ~ O ~ a~
~ r~
J~ @
~n a~ a
h
æ ~
O
H ~: u~ E3 ~U ~U o
F~ O ~H ~ ~ E~
~; O 1~ E~ ~ I E~
~ ~ Pl N 1~3 O ~ ¦ ~ H
U O l~ ~ . O . O ~ _
C~ 1~ 4 ~ ~ 1~ O
z E~ ~
~q ~ :Z ,1
~ ~ o ~ a~ *
m E~ Z Q ~
u~ o ~
.
.
~ 3~
-29-
8CL-6838
As can be seen from the Table above, the
compositions of the invention produce molded
articles useful where impact-resistance is required
and have processing properties useful in blow-
molding technique, particularly where articles of
relatively large size (circa 4-20 Kg) are molded.
,
