Note: Descriptions are shown in the official language in which they were submitted.
126Z9t97
-1- 8CT-4010
POLYCARBONATE/ADDITION POLY~ER BLENDS
This invention relates to thermoplastic
compositions containing a mixed polycarbonate and
thermoplastic addition polymer containing hetero
groups which are admixed to provide compatible blends.
More particularly, it relates to compositions comprising
a mixed polycarbonate which comprises units derived from
a first dihydric phenol which is a bis(hydroxyaryl)
sulfone and a second dihydric phenol, and one or more
thermoplastic polymers containing hetero groups to
provide a compatible blend.
BAC~GROUND OF TH~ INVENTION
At present, it is known to prepare a copolymer
consisting of the reaction product of bis(3,5-dimethyl-
4-hydroxyphenol) sulfone; 2,2-bis(4-hydroxyphenol)
propane and a carbonate precursor. U.S. Patent No.
3,737,409, issued June 5, 1973 to Fox describes a
process for making such a copolymer, which is disclosed
to lend itself to the preparation of textile fibers.
U.S. Patent No. 4,286,075, issued
August 25, 1981 to Robeson et al describes a molding
composition comprising blends of polyarylates derived
from a dihydric phenol and mixtures of terephthalic acid
and isophthalic acid, and at least one thermoplastic
polymer compatible therewith. A blend of the polyaryl-
ates and an aromatic polycarbonate, where a thermo-
plastic compatible polymer is optionally added is also
mentioned.
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- 2 - 8CT-4010
Polymer mixtures such as polycarbonates based on
2,2-bis(2,5-dimethyl-4-hydroxyphenyl) propane and ABS type
addition polymers were disclosed to have better molding
properties than mixtures where the polycarbonate was based
upon 2,2-bis(4-hydroxyphenyl)propane, in U.S. Patent No.
4,172,103, issued October 23, 1979 to Serini et al. Such
blends however showed a decrease in the elastic modulus.
Broadly disclosed, but not claimed, also are
mixtures comprising mixed polycarbonates and thermoplas~ic
resins. However, no data on the physical properties of
these such mixtures can be found in said patent.
When compositions suggested by the disclosure in
the 4,172,103 patent were proposed, as will be shown
hereinafter, they were inferior in certain important
physical properties, e.g., resistance to distortion by
heat and mechanical properties such as stiffness and
strength.
In applicant's Canadian Application Serial No.
441,945, filed November 25, 1983 there are disclosed and
claimed novel compositions comprising mixed polycarbonates
and thermoplastic condensation polymers, alone or in
further combination with addition polymer containing
hereto groups which are admixed to provide compatible
compositions.
SUMMARY OF THE INVENTION
Compatible mixtures of polycarbonates and
thermoplastics resins have generally not been produced
over a broad range of component proportions.
It is an object of this invention to provide
blends of polycarbonate and thermoplastic addition resins
which are compatible in mixtures having widely varying
ratios of components and which have improved properties.
When used herein and in the appended claims,
"compatible" refers to blends or compositions of polymers
in which the component polymers do not undergo phase
separation, thus helping to avoid stratification of the
1~
~262 ~7
8CT-4010
--3--
components during or after processing. Compatibility is
of great significance for an admixture of different resins,
because it ensures homogeneity, and a unity of properties
which greatly facilitates subsequent processing and use
of the composition. Incompatible blends separate into
phases containing predominantly their own separate
components, and thus may be considered to be immiscible.
This characteristic, combined with the often low physical
attraction forces across the phaseboundaries, usually
causes immiscible/incompatible blend systems to have poor
mechanical properties, ~.hus preventing the preparation of
useful polymer blends.
When blends of two polymers exhibit a single
glass transition temperature (Tg), it generally signifies
the resin components are compatible. However, a single Tg
is not a necessary condition for a compatible blend.
In accordance with the present invention, there
are provided thermoplastic compositions comprising a
polycarbonate resin and a thermoplastic addition polymer
resin which have been melt admixed to provide a compatible
composition.
Polycarbonates useful in accordance with the
present invention are well known and any, especially the
aromatic polycarbonates, may be employed. Intrinsic
25 viscosities of from 0.40 to 0.80 dl./g (as measured in
phenol/trichIoroethylene) are preferred. Such resins may
be formed from dihydric phenol, such as hydrocarbon
bisphenol monomerJ ordinarily by condensation with a
carbonate precursor such as carbonyl chloride to provide
a linear polymer consisting of units of the dihydric phenol
linked to one another through carbonate linkages. The
polycarbonate of the invention includes units derived from
a dihydric phenol and a dihydric aryl solfone.
In an especially preferred embodiment, a poly-
carbonate copolymer includes a diphenyl sufone as describedin U.S. Patent 3,737,409 to Fox. For these copolym~rs, a
mole or unit ratio of 1:5 to 5:1, is desirable. The
~2~L97
8CT-4010
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preferred diphenyl sulfone monomer for these resins is
bis(3,5-dimethylhydroxyphenyl) sulfone, also known as
dixylenol sulfone, which may be formed from 2,6-xylenol.
The other preferred monomer is 2,2-bis(4-hydroxyphenyl)
propane, also known as bisphenol.
The addition polymers which are mixed with the
polycarbonate to form the compatible composition are
comprised of units derived from repeat groups including a
heterogroup. Heterogroups are groups containing atoms
besides carbon and hydrogen; such atoms are designate
heteroatoms. The term heterogroup also contemplates the
heteroatoms themselves.
The polymers containing heterogroups can
have the heterogroups (A) as pendant groups on the
polymer chains or as linkages in the polymer chain:
--C ~ C -- --------
- C A C
Typical examples of heteroatoms are oxygen, sulfur,
nitrogen, halogen, etc. Examples of heterogroups are
esters (R-C-O-R'); nitrile (R-CN); anhydride (R-~-O-C-R' );
imide (R-C-N-CI-R"), carbonate (R-O-I-O-R') and the like.
From the foregoing, it follows that polymers within the
scope of this invention, without limitation, are
illustrated by styrene resins, alkyl acrylate resins,
vinyl halide polymers or combinations thereof.
Once formed, the product composition may be
employed (or further processed) in conventional manner.
Its applications include, for example, tough films useful
in packaging. It may also be injection molded or extruded
to produce a variety of useful thermoplastic articles.
~2~2~3~
8CT-4010
--5--
In addition to at least two polymeric components,
the present compositions may contain any of the conventional
additives, for the purposes for which they are known. These
additives include fire-retardants, impact modifiers, pig-
ments,tints, reinforcing materials such as glass fiber,anitoxidants and the like. They may be combined with the
compositions either before or after melt mixing.
Addition polymers suitable for admixing with
the polycarbonate are selected from the group consisting
of styrene resins, alkyl acrylate resins, vinyl halide
polymers, or combinations thereof.
(a) Styrene Resin
Styrene resins suitable for use herein are ABS
type polymers, the molecules of which contain two or more
polymeric parts of different compositions that are bonded
chemically. The polymer is preferably prepared by poly-
merizing a conjugated diene, such as butadiene or a
conjugated diene with a monomer copolymerizable therewith,
such as styrene, to provide a polymeric backbone~ After
formation of the backbone, at least one grafting monomer,
and preferably two, are polymerized in the presence of the
prepolymerized backbone to obtain the graft polymer. These
resins are prepared by methods known in the art.
The backbone polymer, as mentioned, is
preferably a conjugated diene polymer such as
polybutadiene, polyisoprene, or a copolymer, such as
butadiene-styrene, butadieneacrylonitrile, or the like.
The specific conjugated diene monomers
normally utilized in preparing the backbone of the graft
polymer are generally described by the following formula:
X X X X
C = C C = C~
wherein X is selected from the group consisting of hydrogen,
alkyl groups containing from one to five carbon atoms,
chlorine or bromine. Examples of dienes that may be used
1 ~62~9~
8CT-4010
-6-
are butadiene, isoprene, 1,3-heptadiene, methyl-1,3-
pentadiene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-
pentadiene; 1,3- and 2,4-hexadienes, chIoro and bromo
suhstituted butadienes such as dichlorobutadiene,
bromobutadiene, dibromobutadiene, mixtures thereof, and
the like. A preferred conjugated diene is butadiene.
One monomer or group of monomers that may be
polymerized in the presence of the prepolymerized backbone
are monovinylaromatic hydrocarbons. The monovinylaromatic
monomers utilized are generall~ described by the following
formula: X
X ~¢C =C\x
wherein X is as previously defined. Examples of the
monovinylaromatic compounds and alkyl-, cycloalkyl-,
aryl-, alkaryl-, aralkyl-, alkoxy-, aryloxy-, and other
substituted vinylaromatic compounds include styrene,
4-methylstyrene; 3,5-diethylstyrene, 4-n-propylstyrene,
-methylstyrene, a-methyl vinyltoluene, a-chlorostyrene~
~-bromostyrene, dichLorostyrene, dibromostyrene, tetra-
chlorostyrene, mixtures thereof, and the like. Thepreferred monovinylaromatic hydrocarbons used are
styrene and/or c~-methylstyrene.
A second group of monomers that may be
polymerized in the presence of the prepolymerized
backbone are acrylic monomers such as acrylonitrile,
substituted acrylonitrile, and/or acrylic acid esters,
exemplified by acrylonitrile, and alkyl acrylates such
as methyl methacrylate.
The acrylonitrile, substituted acrylonitrile,
or acrylic acid esters are described generically by the
following formula:
:JLZ~,f~';i97
8CT-4010
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X\
C = C Y
X/
wherein X is as previously defined and Y is selected from
the group consisting of cyano and carbalkoxy wherein the
alkoxy group of the carbalkoxy contains from one to about
twelve carbon atoms. Examples of such monomers include
acrylonitrile, ethacrylonitrile, methacrylonitrile, B-
chIoroacrylonitriler -3 -chIoroacrylonitrile, l~-bromo-
acrylonitrile, and ~ -bromoacrylonitrile, methyl acrylate,
methyl methacrylate, ethyl acrylate, butyl acrylate,
propyl acrylate, isopropyl acrylate and mixtures thereof.
The preferred acrylic monomer is acrylonitrile and the
preferred acrylic acid esters are ethyl acrylate and methyl
methacrylate.
In the preparation of the graft polymer, the
conjugat~d diolefin polymer or copolymer exemplified by
a 1,3-butadiene polymer or copolymer comprises about 50
by weight of the total graft polymer composition. The
monomers polymerized in the presence of the backbone,
exemplified by styrene and acrylonitrile, comprise from
about 40 to about 95~ of the total graft polymer
composition.
The second group of grafting monomers,
exemplified by acrylonitrile, ethyl acrylate or methyl
methacrylate, of the graft polymer composition, preferably
comprise from about 10% to about 40% by weight of the
total graft copolymer composition. The monovinylaromatic
hydrocarbon exemplified by styrene comprises from about 30
to about 70% by weight of the total graft polymer
composition.
In preparing the polymer, it is normal to have a
certain percentage of the polymerizing monomers that are
grafted on the backbone combine with each other and occur
1~i2 ~!~7
8CT~4010
--8--
as free copolymer. If styrene is utilized as one of the
grafting monomers and acrylonitrile as the second grafting
monomer, a certain portion of the composition will
copolymerize as free styrene-acrylonitrile copolymer.
In the case where~Z-methylstyrene (or other monomer)
is substituted for the styrene in the composition used
in preparing the graft polymer, a certain percentage of
the composition may be an c~-methylstyrene-acrylonitrile
copolymer. Also, there are occasions where a copolymer
such as ~-methylstyrene-acrylonitrile, is added to the
graft polymer copolymer blend. When a c3raft is polymer-
copolymer blend referred to herein, it is meant optionally
to include at least one copolymer blended with the graft
polymer composition and which may contain up to 90% of
free copolymer.
Optionally, the elastomeric backbone may be
an acrylate rubber, such as one based on n-butyl acrylate,
ethylacylate~ 2-ethylhexylacrylate, and the like.
Additionally, minor amounts of a diene may be copolymerized
in the acrylate rubber backbone to yield improved grafting
with the matrix polymer
These resins are well known in the art and many
are commercially available.
(b) Alkyl Acrylate Resin
The alkyl acrylate resin which may be used herein
includes a homopolymer of methyl methacrylate (i.e., poly-
methyl methacrylate) or a copolymer of methyl methacrylate
with a vinyl monomer (e.g., acrylonitrile, N-allylmaleimide
or N-vinyl maleimide), or an alkyl acrylate or methacrylate
in which the alkyl group contains from l to 8 carbon atoms,
such as methyl acrylate, ethyl acrylate, butyl acrylate,
methacrylate and butyl methacrylate. The amount of methyl
methacrylate is greater than about 70% by weight of this
copolymer resin.
The alkyl acrylate resin may be grafted onto an
unsaturated elastomeric backbone, such as polybutadiene,
1~62~9~
8CT-4010
_g _
polyisoprene, and/or butadiene or isoprene copolymers.
In the case of the graft copolymer, the alkyl acrylate
resin comprises greater than about 50 weight percent of
the graft copolymers
These resins are well known in the art and are
commercially available.
The methyl methacrylate resins have a reduced
viscosity of from 0.1 to about 2.0 dl/g in a one percent
chloroform solution at 25C.
VINYL _HLORIDE POLYMERS
The vinyl chloride polymers suitable for use
herein are polyvinyl chIoride and copolymers of vinyl
chloride and copolymers of vinyl chloride with
olefinically unsaturated polymerizable compounds which
contain at least 80 percent by weight of vinyl chloride
incorporated therein.
Olefinically unsaturated compounds which are
suitable for copolymerization include vinylidene halides,
such as vinylidene chloride and vinylidene fluoride,
vinyl esters, such as vinyl acetate, vinyl propionate,
vinyl butyrate, vinyl chloroacetate, vinyl benzoate,
acrylate and c<-alkyl-acrylate and their alkyl esters,
amides and nitriles, methacrylic acid, maleic acid or
anhydride,methyl methacrylate, ethyl acrylate, 2-ethyl
hyxylacrylate, butyl methacrylate, 2-hydroxypropyl
acrylate, acrylamide. N-methyl acrylamide, acrylonitrile
and methacrylonitrile, aromatic vinyl compounds, such as
styrene and vinyl naphthalene and olefinically unsaturated
hydrocarbons such as ethylene-bicyclo [2,2,2]-hept-2-ene
30 and bicyclo-[2,2,1]hepta-2,5~diene. Polymerized vinyl
acetate may be hydrolyzed to provide vinyl alcohol
moieties in the polymer.
These vinyl chloride polymers are well known
in the art and can be prepared by the usual methods of
solution, emulsion, suspension, bulk or mass polymer-
ization.
6,'Z~97
8CT-4010
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Vinyl chloride polymers which have molecular
weight of from about 40,000 to about 60,000 are preferred.
The intrinsic viscosities (I.V.) are all
determined in a solvent mixture comprising 60-40 w/w
phenol-tetrachloroethane at 30C.
In the Examples which follow, the general
procedure for mixing, molding and testing is as follows:
The components are melt mixed in an extruder operating
under the following conditions:
1 0 TEMPE~ATURE
RPM ZONEZONE ZONE ZONEDIE DIE AMP
12 ~ 3~ 4 2
. ~
400 F425 F 425 F 440 F450 F4S0 F 10.0
The extruded, blended polymer strands are chopped into pellets
which are dried and injection molded (into specimens suitable
for testing) in a 3 ounce/75 ton Newbury lnjection molding
- machine operating under the following conditions:
Barrell Temperature 465 F
Mold Temperature 150 F
Molding Pressure 1500 psi
The specimens were evaluated for flexural properties (ASTM
D790) and heat distortion temperature (ASTM D256)~
EXAMPLE 1
A physical mixture of 50 percent by weight of
dry polycarbonate having a 1:1 mole ratio of sulfone to
bisphenol and 50 percent by weight of ABS resin
(manufactured by Borg Warner Clenical under the trade mark
Cyclolac GMS) are extruded blended, injection molded and
tested for properties. The results are presented in
Table 1 below.
1'~62~97
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COMPARATIVE COMPOSITION A
-
A physical mixture of 50 percent by weight of
dry 2,2-bis(3,5 dimethyl-4-hydroxyphenyl)propane poly-
carbonate and 50 percent by weight ABS resin (manufactured
by Borg Warner Chemical under the trade mark Cyclolac GSM)
are extruded blended, injection molded, and tested for
properties. The results are presented in Table 1 below.
TABLE I
POLYCARBONATE BLENDS WITH ABS
Comparative
Composition A Example 1
Tg C 109,178 147
TDT oca 106 117
Flex modulus, psi374,000 405,000
Flex strength, psi9,210 14,000
Tensile modulus, psiC376,000 381,000
Tensile Strength, psi6,710 8,200
a) HDT-ASTM D648; b) Flexural properties-ASTM D790;
c) Tensile properties-ASTM D638
In each of the properties listed the bisphenol-A
sulfone polycarbonate blend is superior to that of the
2,2-bis(3,5 dimethyl-4-hydroxyphenyl)propane polycarbonate.
Indeed, the flexural strength is over 50~ higher with the
bisphenol-A sulfone polycarbonate.
EXAMPLE 2
A physical mixture of 30 percent by weight of dry
polycarbonate having a 1:1 mole ratio of sulfone to
bisphenol and 70 percent by weight of Cyclolac GSM-ABS
resin are extruded blended, injection molded, and tested
for properties. The results of this Example are presented
in Table II below.
9'~
8CT-4010
-12-
TABLE II
Property Example 2 Cyclolac GSM*
-
Tg ( C) 137 124
HDT ( C) 103 96
Flex. Mod., psi428,000 260,000
Flex. Str., psi12,300 8,000
Tensile Mod., psi357,000 260,000
Tensile Str., psi7,200 6,300
. _
*Control
EX~MPLE 3
A physcial mixture of 50 percent by weight of dry
polycarbonate having a 1:1 mole ratio of sulfone to
bisphenol and 50 percent ABS resin (manufactured by
Monsanto Company under the trade mark Lustran 461) are
extruder blended, injection molded, and tested for
pFopertles. The results of thls Example are as follows:
PropertyComposition Lustran 461
Tg ( C) 126 106
HDT ( C~ 105 89
20 Flex. Mod., psi432,000 420,000
Flex. Str., psi12,800 10,000
Tensile Mod., psi420,000 340,000
Tensile Str., psi7,300 6,000
EXAMPL~ 4
A physical mixture of 50 percent by weight of dry
polycarbonate having a 1:1 mole ratio of sulfone to
bisphenol and 5Q percent by weight of SAN-poly(styrene-
acrylonitrile) containing about 28~ acrylonitrile are
extruder blended, injection molded, and tested for
properties. Comparative results are as follows:
lZ62~97'
8CT-4010
-13-
Property C~o ition S~N
Tg ( C) 128 107
HDT ( C) 110 86
Flex. Mod., psi490,000 396,000
Flex. Str., psi14,000 15,900
EXAMPLE 5
A physical mixture of 20 percent by weight of dry
polycarbonate having a lol mole ratio of sulfone to
bisphenol and 80 percent by wei~ht of SAN are extruder
blended/ injection molded, and tested for properties.
Comparative results are as follows:
Composition SAN
HDT ( C) 91 107
Flex. Mod., psi520,000 396,000
15 Flex. Str., psi16~300 15,900
EXAMPLE 6
A physical mixture of 80 percent by weight of dry
polycarbonate having a 1:1 mole ratio of sulfone to
bisphenol and 20 percent by weight of SAN are extruder
blended, injection molded, and tested for properties.
Comparative results are as follows:
Composition SAN
HDT ( C) 140 107
Flex. Mod., psi455,000 396,000
25 Flex. Strenth, psi12,400 15,000
EXAMPLE 7
A physical mixture of 50 percent by weight of dry
polycarbonate having a 1:1 mole ratio of sulfone to
bisphenol and 50 percent by weight of poly(styrene-methyl
1~2~97
8CT-4010
-14-
methacrylate) containing 30% methyl methacrylate are
extruder blended, injection molded, and tested for
properties. The results are presented below.
HDT ( C) 89
Flex. Mod., psi 426,000
Flex. Str., psi 12,300
EXAMPLE 8
A physical mixture of 80 parts dry polycarbonate
having a 1:1 mole ratio of sulfone to bisphenol and 40
parts of polyIstyrene-maleic anhydride) (manufactured
by Arco under the designation Dylark 232) are extruder
blended, injection molded and tested for properties. The
results are described below.
HDT, C 130
Flex. Mod., psi470,000
Flex. Str., psi14,900
EXAMRLE 9
A phys cal mixture of 45 percent by weight of dry
polycarbonate having a 1:1 mole ratio of sulfone to
bisphenol, 45 percent by weight SAN, and 10 percent by
weight of an acrylate based polymer called KM 330 (sold
by Rohm and Haas) are extruder blended, injection molded,
and tested for properties. The results are described below.
Flex. Mod., psi 403,000
Flex. Str., psi 15,700
HDT, C 110
EXAMRLE 10
A physical mixture of 25 parts dry polycarbonate
having a 1:1 m~,le ratio of sulfone to bisphenol and 75
parts of Rovel ~EPDM grafted SAN) (manufactured by Uniroyal)
are extruder blended, injection molded and tested for
properties. The results are described below.
1~62~9~
8CT-4010
-15-
I~V. 0.90
Tg C 116
HDT 93
Notched Izod ft-lb/in 4.1
EXAMPLE 11
A physical mixture of 40 percent by weight of dry
polycarbonate having a 1:1 mole ratio of sulfone to
bisphenol, 40 percent by weight polymethylmethacrylate,
and 20 percent by weight of poly(ethylene terephthalate)
are extruder blended, injection molded, and tested for
properties. The results are described below.
HDT, C 101
Flex. Mod., psi 327,000
Flex. Str., psi 12,000
EXAMPLE 12
A physical mixture of 26 percent by weight of dry
polycarbonate having a 1:1 mole ratio of sulfone to
bisphenol, 35 percent by weight of polyvinylchloride, 26
percent by weight of poly(ethylene terephthalate) and 10
percent by weight of an acrylate based polymer called
KM-611 (sold by Rohm and Haas) are melt mixed, compression
molded and tested for properties. The results are
described below.
Flex. Mod., psi330,000
Flex. Str., psi8,900
Notched Izod ft-lbs/in 2.2
POLYMER SYNTHESIS
The dixylenol sulfone/bisphenol A (DXS/BPA)
described in the foregoing examples were prepared employing
interfacial polymerization, in which a rapidly stirred two
phase mixture of aqueous caustic~ polymer solvent,
bisphenols, a phase transfer catalyst, and monofunctional
1~24~7
8CT-4010
-16-
chain terminators is phosgenated. The growing polymer
dissolves in po]ymer solvent, unreacted bisphenols
dissolve in the aqueous caustic phase and the polymer
forms at the interface. The polymer is isolated by
precipitation in methanol and dried. The applicable
technology of the synthesis of polycarbonates is
described in "Chemistry and Physics of Polycarbonates"
by H. Schnell (Interscience, 1964).
Preferred blends are admixtures of a polycarbonate
resin including units derived from a first dihydric phenol,
which is a bis(hydroxyaryl)sulfone and a second dihydric
phenol, and a thermoplastic which is the resin product
of a condensation polymerization reaction. These resin
products would include vinyl addition polymers containing
hetero groups.
Obviously, other modifications and variations
of the present invention are possible in the light of
the above teachings. It is, therefore, to be understood
that changes may be made in the particular embodiments
of the invention described which are within the full
intended scope of the invention as defined by the appended
claims.
