Note: Descriptions are shown in the official language in which they were submitted.
1078091
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POLYMERIC POLYBI.~D COMPOSITIOtlS TOUGHE~IED BY ADDITIC~
OF llnUID POiY~II'RS ~E' ~ CO~JJUC~T~D DIL~ O~'O;I~
It is known that polyalkenyl aromatic polymers such as
polystyrene and styrene-acrylonitrile polymers (SAN) can have
their toughness properties such as impact strength, elon~ation
and overall toughness improved by incorporating commercial diene
rubbers having a molecular weight of 30,00~ to 250,000 in amounts
of 2 to 36 percent by weight. HIPS and ABS are used co~ercially
as tough engineering plastics for molding and sheet products
having great commercial utility.
The engineering properties of rubber reinforced HIPS and
ABS polymeric polyblends need further improvement to meet the
ever increasing industrial requirements of such plastics. In
particular, the elongation at fail without loss of tensile
stren~th has been found to be a critical property of toughness
that has been only adequate in known HIPS and ABS polyblends,
' It is known to add lubricants such as mineral oil and
waxes to improve the elongation at fail of such polyblends.
However, such additives lower the tensile strength and heat dis-
tortion temperature and have not improved overall toughness.
The present invention provides HIPS and ABSpolyblends having improved elongation at fail wi'cll~ut
loss of tensile strength giving i~proved overall toughness
by the blending of liquid polymers of conjugated diene monomers
in the polyblend and can be prepared by polymeri~ation
processes ~herein the incorporation of a liquid polymer o~
a con~ugated diene ~onomer in the -~olymeri~in~ composition
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does not inhibit tl~e polymerization process and Provides
a compatible additive for the rubber phase of the ~oly-
blend that i~proves elongation at fail and low ten-
, perature properties without loss of tensile strength or heat
distortion temperature of the polymeric polyblend.
It has been found that the foregoing and related objec-
tives can be readily attained broadly in a polymeric polyblend
composition comprising the polymerization product of:
(A) 13 to 97 parts by weight of at least
10one monoalkenyl aromatic monomer,
(B) 0 to 8S parts by weight of at least
one monoalkenyl nitrile monomer,
(C) 2 to 36 parts by weight of a diene
rubber, and about
15(D) 0.2 to 20 parts by weight of a liquid
polymer of a conjugated diene monomer,
the total polyblend being 100 parts
by weigh~.
The invention then is broadly applicable to improved
polymeric polyblend compositions of the HIPS and ABS class of
polyblends and their preparation wherein said polyblends have
improved elongation at fail without loss of tensile strength by
the incorporation of 0.2 to 20 parts by weight of a liquid poly-
.mer of a conjugated diene monomer in the polyblend, t~e poly-
blend being 10~ parts by weight.
08-12-0334 1078091
Polyblcnd Preparation -'
Those skilled in the art are aware that the term pol~-
blend as employed herein me~ns a` mixtu~e of polymers that are
substantially incompatible, ~IP~ polyblends are mixtures of
polystyrene as a matrix phase with a diene rubber phase dis-
persed therein wherein the rubber phase has been grafted with
polystyrene to aid in its dispersiqn as particles in the po~-
styrene phase. ABS polyblends are mixtures of diene rubbers
dispersed in a SAN polymer matrix phase with the rubber phase
grafted with SAN to aid in it,s dispersion as particles. The
polyblends may be prepared by:
(1) mechanical melt mixing of ~he two phases;
(2) mass polymerizing a solution of the diene
rubbers dissolved in the monomers under
15 ' agitation either batchwise or continuously;
~3) a combination of mass and suspension polymer-
ization wherein a monomer/rubber solution is
mass polymerized to 10 to 50 percent conver-
~ion under agitation followed by suspending
20~ ' the polymerization mixture in an inert liquid
Ce.g. water) and completing the polymerization,
and
(4) emuls-on polymerizing the monomers wherein
the monomers are added to a rubber latex
- emulsion, emulsi~ied with the rubber and
polymerized as a monomer~rubber mixture.
1078091
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These methods are known to those skilled in the art.
U.S.P. 3,488,743 teaches the mass/suspension polymerization of
HIPS polyblends and the melt mixing of HIPS polyblends in Ex-
ample 1. U.S.P. 3,509,237 teaches the emulsion polymerization,
the mass/suspension polymerization and melt blending of ABS
polyblends in Example 1, parts A, B and C respectively. The
continuous mass polymerization of HIPS and ABS polyblends has
been taught in U.S.P. 3,511,895.
The polyblend compositions of the present invention are
HIPS and ABS polyblends which have improved elongation at fail
yet high tensile strength, by the addition of about 0.2 to 20
parts by weight of a liquid polymer of a conjugated diene mono-
mer during the melt blending or polymerization of the polyblend.
The polyblend composition of the present invention can
be prepared as the polymerization product of methods (2), (3)
and (4) wherein the product is improved by the addition of about
0.2 to 20 parts of a liquid polymer of a conjugated diene mono-
mer to the polymerizing mixture of monomers and rubber. The
liquid polymer may be added as part of the feed composition or
at any stage of the polymerization. The liquid polymer has not
been found to effect the polymerization adversely, e.g. the
rates of polymerization, hence, can be added at any stage of
conversion. Preferably, it is most economically added as part
of the feed composition in the mass and massJsuspension pro-
cesses. In the emulsion processes it is preferably added mosteconomically to the rubber latex as a solution in said monomers
before polymerization. However, if the rubber latex is to be
agglomerated to form larger particles it is preferred to add the
liquid polymer with the monomers. It is ~nown to coagulate the
1078091
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rubber latex, separate the rubber and disperse it to the mono-
mers followed by mass polymeri~ation. It is preferred in such
processes to add the li~uid polymers with the rubber to the
monomers before or during mass polymerization. It is known to
solution polymerize said polyblend compositions or to mass
polymerize with 5 to 20 percent of a diluent to control the
heats of polymerization. In such processes it is preferred to
add the liquid polymers to the initial polymerizing composition,
although they can be added at any stage of polymerization if
desired.
,he melt blending of polymers to form polyblends is
known to those skilled in the art. Such melt blending can be
carried out in commercial extruders, banburys or any high shear-
ing mixer or colloiding device wherein the mixing and colloiding
of the matrix polymers, rubbers and liquid polymers are uni-
formly mixed and blended at the melt temperature of the matrix
phase. HIPS polyblends can be melt blended at temperatures of
150C. to 260C., preferably 200C. to 240C., whereas ABS are
melt blended at temperatures of 215C. to 260C., preferably
235C. to 250C.
Polyalkenyl Aromatic Polymers and Monomers
The alkenyi aromatic polymer of the polyblend comprises
at least one monoalkenyl aromatic monomer of the formula
`C = CH2
Ar
where Ar is selected from the group consisting of phenyl, halo-
phenyl, alkylphenyl and alkylhalophenyl and mixtures thereof
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and X is selected from the group consisting of hydrogen and an
alkyl radical of less than three carbon atoms.
Exemplary of the monomers that can be employed in poly-
merization are styrene; alpha-alkyl monovinylidene monoaromatic
compounds, e.g. alpha-methylstyrene, alph-ethylstyrene) alpha-
methylvinyltoluene, etc.; ring-substituted alkyl styrenes, e.g.
vinyl toluene, o-ethylstyrene, p-ethylstyrene, 2,4-dimethylsty-
rene, etc.; ring-substituted halostyrenes, e.g. o-chlorostyrene,
p-chlorostyrene, o-bromostyrene, 2,4-dichlorostyrene, etc.;
ring-alkyl, ring-halo-substituted styrenes, e.g. 2-chloro-4-
methylstyrene, 2,6-dichloro-4-methylstyrene, etc. If so de-
sired, mixtures of such monovinylidene aromatic monomers may be
employed. The average molecular weight of the monoalkenyl aro-
matic polymers can range from 20,000 to 100,000 Staudinger,
prefera~ly 40,000 to 60,000.
ln the HIPS polyblends the monoalkenyl aromatic monomer
can be present in amounts from about 13 to 98 parts, preferably
from about 60 to 97 parts and most preferably from about 80 to
9? parts by weight the polyblend being 100 parts by weight.
Diene Rubbers
The diene rubbers of the polyblend are any rubber poly-
mer (a rubbery polymer having a second order transition tempera-
ture not higher than 0 centigrade, preferably not higher than
-20 centigrade, as determined by ASTM Test D-746-52T) of one or
more of the conjugated, 1,3-dienes, e.g. butadiene, isoprene,
2-chloro-1,3 butadiene, 1 chloro-1,3 butadiene, piperylene,
etc., and also cyclopentadiene. Such rubbers include copolymers
and bloc~ copolymers of conjugated 1,3-dienes with up to an
equal amount by weight of one or more copolymerizable mono-
~ 078091
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ethylenically unsaturated monomers, such as monovinylidene aro-
matic hydrocarbons (e.g. styrene; an aralkylstyrene, the ar-
ethyl-styrenes, p-tert-butylstyrene, etc.; an alphamethylsty-
rene, alphaethylstyrene, alpha-methyl-p-methyl styrene, etc.;
S vinyl naphthalene, etc.); arhalo monovinylidene aromatic hydro-
carbons (e.g. the o-, m- and p-chlorostyrene, 2,4-dibromosty-
rene, 2-methyl -4- chlorostyrene, etc.); acrylonitrile; meth-
acrylonitrile; alkyl acrylates (e.g. methyl acrylate, butyl
acrylate, 2-ethylhexyl acrylate, etc.), the corresponding alkyl
methacrylates; acrylamides (e.g. acrylamide, methacrylamide, N-
butylacrylamide, etc.); unsaturated ketones (e.g. vinyl methyl
ketone, methyl isopropenyl ketone, etc.); alpha-olefins (e.g.
ethylene, propylene, etc.); pyridines; vinyl esters te.g. vinyl
acetate, vinyl stearate, etc.); vinyl and vinylidene halides
(e.g. the vinyl and vinylidene chlorides and vinylidene chlor-
ides and bromides, etc.); and the like.
Although the rubber may contain up to about 2.0 percent
of a crosslinking agent, based on the weight of the rubber-form-
ing monomer or monomers, crosslinkin~ may present problems in
dissolving the rubber in the monomers for the graft polymeriza-
tion reaction. In addition, excessive crosslinking can result
in loss of the rubbery characteristics.
~ preferred group of rubbers are the stereospecific
polybutadiene rubbers formed by the polymerization of 1,3 buta-
diene. The~e rubbers have a cis-isomer content of about 30-98
percent and a trans-isomer content of about 70-2 percent an~
generally contain at least about 85 percent of polybutadiene
formed by 1,4 addition with no more than about 15 percent by 1,2
addition. Mooney viscosities of the rubber (ML-4, 100C.) can
1078091
C-08-12-0334
range from about 20 to 70 with a second order transition tem-
perature of from about -50C. to -105C. as determined by ASTM
Test D-746-52T.
In the HIPS polyblends the diene rubber can be present
in amounts of from about 2 to 36 parts by weight, preferably
from about 2 to 20 parts by weight, the polyblend being 100
parts by weight.
In the ABS polyblends the diene rubber can be present in
amounts of from about 2 to 60 parts by weight, preferably from
about 2 to 36 parts by weight, the polyblend being 100 parts by
weight.
Alkenyl Nitrile Monomers and Polymers
Exemplary of the monoalkenyl nitrile monomers are those
having the formula:
CH2 = I - CN
R
wherein R is selected from the group consisting of hydrogen and
alkenyl radicals containing 1 through 4 carbon atoms. The
monoalkenyl nitrile monomers can be selected from the group
consisting of acrylonitrile, methacrylonitrile, ethacrylonitrile
and mixtures thereof.
In the ABS polyblends, the polymerizable monomers con-
tain at least 13 parts by weight of monoalkenyl aromatic mono-
mer and preferably from about 13 to g7 parts, most preferably
from about 50 to 75 parts by weight. The monoalkenyl monomers
can be present in amounts of from about 5 to 35 parts, most
preferably from 20 to 50 parts by weight, the polyblend being
100 parts by weight.
_ g _ .
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Exemplary of the monomers which may be interpolymerized
with the monoalkenyl aromatic and monoalkenyl nitrile monomers
are conjugated 1,3 dienes, e.g. butadiene, isoprene, etc.;
alpha- or beta-unsaturated mono-basic acids and derivatives
thereof, e.g. acrylic acid, methyl acrylate, ethyl acrylate,
butyl acrylate, 2-ethylhexyl acryl~te, methacrylic acid and the
corresponding esters thereof, acrylamide, methacrylamide; vinyl
halides such as vinyl chloride, vinyl bromide, etc.; vinylidene
chloride, vinylidene bromide, etc.; vinyl esters such as vinyl
acetate, vinyl propionate; etc.; dialkyl maleates or fumarates
such as dimethyl maleate, diethyl maleate, dibutyl maleate, the
corresponding fumarates, etc. Small amounts of the above mono-
mers can be used in HIPS and ABS polyblends, for improved
properties, preferably 1 to 25 parts, most preferably 5 to 15
parts by weight, the polyblend being 10~ parts by weight. Such
monomers can be used with the matrix monomers or the diene
rubber monomers as copolymer monomers.
Liquid Polymers of a Conjugated Diene Monomers
The liquid polymers of a conjugated diene monomer can
be prepared in mass, suspension, emulsion or solution. The
liquid polymer can be a homopolymer of a conjugated diene (di-
olefin~ monomer of 4 to 6 carbon atoms, e.g. 1,3 butadiene, 1
or 2 chlorobutadiene (chloroprene), isoprene, piperlene, cyclo-
pentadiene, 2~3 dimethyl butadiene or copolymers of said mono-
mers. Such liquid polymers of a conjugated diene monomer alsoinclude copolymers of diene monomers with monoalkenyl aromatic
and~or monoalkenyl nitrile monomers such as styrene, alpha
methyl styrene, acryloni~rile, methacrylonitrile and the like.
The liquid polymer of a copolymer of a conjugated diene monomer
107809~ .
C-08-12-0334
can have up to about 50 percent by weight of the above comono-
mers preferably ùp to about 20 percent. One procedure for pre-
paring liquid polymers of conjugated diene monomers is taught
in U.S.P. 3,462,516 using alkali metal catalysis in particular
sodium. The liquid polymers have molecular weights in the range
of 300 to 20,000, preferably 500 to 10,000. These polymers
are normally liquid and have no measurable large rotor Mooney
value at 212C., hence, are not considered to be rubbers. ~he
liquid polymers can be terminated with xanthate, mercaptan,
hydroxyl or carboxyl groups. Other terminating groups can be
used, such as SOH, S02H, S03H, SeO24, SeO3H~ LiO2H, SnO2H,
SbO2H, SbOH, SbO3H, TeO2H and the like.
Another procedure commonly used involved solution poly-
merization in the presence of the alkali metal catalyst lithium
as taught in U.S.P 3,462,516. The general reaction can be il-
lustrated graphically as follows:
M- R- M~ ~(C4H6)-~ M- R(C4H6~Y M
M-(C4H6)n -R- (C4H6)x-n M
or combinations thereof in which M R M is an organoalkali
metal compound. A specific example is:
Li- (CH )4 ~Li~x(CH2= CH- CH= CH) --~
~i -(CH2- CH =CH- CH~)n- (C~)4
- (CH2 -C~ - CH~~~H2)x-n
In the specific example9 1,4-addition of butadiene is
shown; however, it should be understood that 1,2-addition and
combinations of 1,4 and 1,2-addition can also occur.
Treatment of this resulting polymer with carbon dioxide
- and a mineral acid results in the lithium atoms ~eing replaced
~078091
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by a carboxy group with the lithium separating as the salt of
the acid. Thereby such treatment results in a carboxy-terminated
polymer. A hydroxy-terminated polymer containing reactive hy-
droxy end groups can be obtained by reacting the polymer having
S the terminal lithium atoms with an epoxy compound at elevated
temperatures, followed by treatment with a mineral acid to re-
place the lithium atoms with hydrogen atoms.
Liquid rubbers are formed in the range of between -100
and ~150C., preferably between -75 and ~75C. The particular
temperatures employed will depend upon both the monomers and the
initiators used in preparing the polymers and one skilled in the
art would have no difficulty in choosing the particular initia-
tor and the particular pressures and temperatures necessary to
achieve a particular result. This is well within the knowledge
of the art. The amount of catalyst employed can vary but is
preferably in the range of between about 1 and about 30 milli-
moles per 100 grams of monomer. It is preferred that the poly-
merization be carried out in the presence of a suitable diluent
such as benzene, toluene, cyclohexane, xylene, n-butane or the
like. Generally, the diluent is selected from hydrocarbons such
as paraffins, cycloparaffins, and aromatics containing from 4 to
10 carbon atoms per molecule.
The above liquid polybutadienes have functional terminal
groups only. A preferred class of liquid diene polymers are
those that are terminated with other than functional groups
classified as telomers. U.S.P. 3,760,025 discloses such telomers
having telogens or terminal groups terminating the polymer of
diene monomers or taxogens.
The telogens which are used are aromatic compounds, es-
- ~2 -
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pecially aromatic hydrocarbon compound~ containing at least one
hydrogen capable of being replaced by a lithium atom but devoid
of any other substituents as, for instance, hydroxyl, chlorine,
bromine, iodine, carboxyl, and nitro, which substituents are
reactive with the organolithium compositions-or complexes which
are utilized as catalysts. Illustrative examples of such telo-
gens are benzene, Cl-C4 mono-, di-and trialkyl benzenes exem-
plified by toluene, ethylbenzene, n-propylbenzene, isopropyl-
benzene, o-, m- and p-xylenes; 1,3,5-trimethyl-benzene; n-,
sec- and tertbutylbenzenes; cyclohexylbenzene; alkyl, notably
Cl-C4, and cycloalkyl substituted polycyclic aromatic compounds
exemplified by 1,2,3,4-tetrahydronaphthalene, l-methylnaphtha-
lene, l-isopropylnaphthalene, 1,3-isobutylnaphthalene, and 1-
cyclohexylnaphthalene; alkoxy-aromatic compounds exemplified by
anisole; 1,3-dimethoxybenzene; mono-propoxybenzene; 1-methoxy-
naphthalene and l,3-dimethoxynaphthalene; dialkylamino-aromatic
compounds, notably those in which the alkyl is Cl-C4, exempli-
fied by dimethylaminobenzene; 1,3-bis-(diisopropylaminobenzene)
and l-dimethylaminonaphthalene. Especially satisfactory is
toluene. Said telogens usually provide one terminal phenyl
group per diene polymer chain with the other end group being
the organo group of the organo metallic initiator, e.g., a
lower alkyl.
U. S. Patents 3,678,121 and 3,751,501 describe other
liquid diene polymers having various microstructures for the
diene moiety. Such liquid ~iene polymers can range from 75 to
95 percent unsaturation having a polybutadiene microstructure
of about 5 to 40 percent trans 1,4, about 5 to ~5 cis, 1~4 and
about 35 to 90 percent 1,2 vinyl ranBing preferably from about
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500 to 3000 in molecular weight and having 3 to 10 percent by
weight of terminal aralkyl groups. The polybutadiene micro-
structure may also contain from about 5 to 25 percent of
cyclized 1,2 structure. The terminal lithium group can be re-
moved with aralkyl or with acids such as hydrochloric to in-
troduce a hydrogen to terminate the chain.
Such liquid polymers of a conjugated diene monomer,
having unreactivity terminated polymers, are commercially avail-
able from the (1) Lithium Corporation of America, 2 Pennsylvania
Plaza, New York, N. Y., under the Trademark "Lithene"; (2) The
Richardson Company of Melrose Park, Illinois under the Trade-
mark "Ricon" or (3) The Dynachem Corporation, Sante Fe Spring~,
California under the Trademark "Hystel".
The invention then is broadly applicable to improved
polymeric polyblend compositions of the HIPS and ABS class of
polyblends and their preparation wherein said polyblends have
improved elongation at fail without loss of tensile strength by
the incorporation of 0.2 to 20 parts by weight of a liquid poly-
mer of a conjugated diene monomer in the polyblend, the poly-
blend being 100 parts by weight. On a weight percent basis,about 5 to 50, preferably 10 to 30 weight percent of the diene
rubber in the polymeric polyblend can be replaced with the
liquid polymer of a diene monomer described above to provide a
polymeric polyblend with improved elongation at fail and overall
toughness.
The following examples illustrate ways in which t~e
principle of the invention has been applied, but are not to be
construed as limiting in scope.
- 14 -
1078091
C-O 8-12-0 3 34
EXAMPLE .1
HIPS POLYBLEND PREPARATION
.
In a reaction vessel were stirred together 8 . O parts of
a butadiene homopolymer having a molecular weight of about
94,000 and 92.0 parts of styrene monomer. The admixture also
contained 0.1 part di-tert-butyl peroxide, 0.05 part tert-do-
decyl mercaptan, and minor amounts of antioxidant and mineral
oil.
Polymerization en masse was conducted to approximately
30.0 percent conversion and the syrup thus produced was there-
after admixed with 425.0 parts of water and a suspending agent
formulation provided by 0.5 part of an interpolymer of 95.5 mol
percent acrylic acid and 4.5 mol percent 2-ethylhexyl acrylate,
0.3 part calcium chloride and 1.0 part of the condensation prod-
uct of naphthalene sulfonic acid and aldehyde sold by R. T.
Vanderbilt under the Trademark DARYAN. The suspension was
stirred and initially heated to about 100 centigrade; there-
after, it was heated with stirring to about 155 centigrade for
a polymerization cycle rate of about four hours and at a pres-
sure of about 6.3 to 7.4 ~g/ cm2. Thereafter, the
batch was cooled, centrifuged, washed and dried to recover the
polymerized product in the form of small spherical beads. The
beads recovered from the polymerization process contained about
8-.0 percent by weight rubber which had been grafted to a super-
8trate:substrate ratio of 170:100, and the rubber particles had
a diameter of 0.4 to 2.0 microns with an average size of about
n. 8 micron.
Thereafter, 62.5 parts of the beads thus produced were
melt ~lended with 37.5 parts of polystyrene homopolymer, 0.3
1078091
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parts of an alkylated phenol antioxidant and 0.2 parts of a
stearate soap to provide a HIPS polyblend composition having 5
percent by weight of rubber. An extruded specimen produced
therefrom was found to have a tensile at yield of 2Q5 I~g/cm2 and
at fail 254 Kg/cm2 with a elongation at fail of 22 percent as de-
termined by ASTM D-638 tests.
EXAMPLE 2
ABS POLYBLEND PREPARATION
Part A
To a 250.0 parts of a latex of butadiene~acrylonitrile
copolymer (93:7) containing 50.0 percent solids and approximately
1.0 part of rubber reserve soap as an emulsifier were added 70.0
parts water, 1.0 part rubber reserve soap and 1.0 part potassium
persulfate.
This emulsion was heated to 65 centigrade with stirring
and then there were added thereto over a period of about six
hours 140.0 parts styrene, 60.0 parts acrylonitrile and 3.0 parts
of terpinolene. The emulsion was held at temperature for one
hour thereafter with stirring, cooled, coagulated by the addi-
tion of magnesium sulfate and the coagulant was then washed and
dried. The resulting graft copolymer has a superstrate to sub-
strate ratio of about 0.9:1.0 and a particle size ~number
average) of about 0.14 micron.
Part ~
Fourteen parts of a soluble ~utadiene rubber were dis-
solved in 26.0 parts of acrylonitrile and 60.0 parts styrene.
There were added thereto 0.07 part of a mixture of tertbutyl
peracetate, 0.05 part di-tert-butyl peroxide and stabilizers.
~he mixture was heated to 100~ centigrade with stirring. ~er-
1078091
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pinolene was added as a chain transfer agent over a period of
approximately five hours, at the end of which time an additional
0.4 part was added.
At 30.0 pereent conversion of the monomers, the par-
tially polymerized syrup was dispersed in 120.0 parts water to
which was added 2.0 parts styrene and, as a suspending agent,
0 3 part of an interpolymer of 95.5 mol percent of acrylic acid
and 4.5 mol percent of 2-ethylhexyl acrylate which has a speci-
fic viscosity of about 4.0 as determined in a 1.0 percent solu-
tion in water at 25 centigrade. The resulting suspension was
stirred and heated to polymerize the remaining monomer, cooled,
centrifuged, washed and dried to recover the graft copolymer in
the form of small spherical beads. The ratio of superstrate to
substrate was about 0.9 to 1.0:1.0, and the particle size was
about 0.9 micron.
Part C
The graft copolymer of Part A (21.4 parts) was melt
blended with 78.6 parts of a SAN copolymer to form a polyblend
having about 7.47 parts of diene ru~ber and tested. The tensile
strength at yield was 6,600 psi. (4.6 x 106 kgs/sq.m.), at fail
6,000 psi. (4.2 x 106 kgs/sq.m.) and the elongation at fail was
25 percent. (ASTM D-638).
Part D
The graft copolymer of Part (B) (51.0 parts) was blended
with 47.5 parts of SAN copolymer and 1.5 parts carbowax provid-
ing 7.21 parts by weight of diene rubber in the polyblend. The
tensile strength at yield was 6,000 psi. (4.2 x 106`kgs/sq.m.)
and at failure, 5,600 psi. (3.~ x 106 kgsJsq.m.) giving an
elongation at fail of about 20 percent (ASTM D-638).
- 17 -
1078091
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- _XAMPLE 3
HIPS Polyblend with Liq~id Polymers
Example 1 was repeated using 95 parts of styrene monomer,
4 parts of a homopolymer of butadiene (Mooney viscosity of 35)
and 1 part of a liquid polymer of a butadiene monomer ~Lithene
QH, 35 percent vinyl, molecular weight 3,000). The polymeriza-
tion product contains 4 parts of a diene rubber and 1 part of
liquid polymer comparable to the final blended product of Ex-
ample 1 having 5 parts of 5 percent by weight of a diene rubber.
The tensile strength at yield was 3,000 psi. (2.1 x 106 kgs/sq.
m.), a tensile strength at fail of 3,500 psi. (2.5 x 106 kgs~
s~.m.), and an elongation at fail of 46 percent (ASTM D-638).
It is evident that the polyblend having 1 part by weight (20
percent by weight) of a diene rubber replaced with a liquid
polymer of a butadiene monomer unexpectedly had about 100 per-
cent increase in elongation at fail without a loss of tensile
strength at yield providing superior overall toughness.
' EXAMPLE 4
ABS Polyblends with Liquid Polymers
Example 2, Parts A and C were repeated using 25.0 parts
or 20 percent by weight of a liquid polymer of a butadiene mono-
mer Lithene QH as 25.0 parts of the butadiene/acrylonitrile
diene rubber in Part A. The tensile strength (T.S.) of the
polyblend at yield was found to be 6,000 psi (4.2 x 106 kgs~
sq.m.) and the T.S. at fail to be 6,500 psi. (4.6 x 10~ kgs/
s~.m.) with the elongation at fail being about 51 percent
(ASTM D-63B).
Example 2, Parts B and D were repeated replacing 2.8
parts by weight of the diene rubber with 2.8 parts ~20 percent
- 18 -
1078091
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by weight) of the liquid polymer in Part B. The tensile strength
at yield of the polyblend was 6,500 psi. (4.6 x 106 kgs~sq.m.). 9
at fail 7,000 psi (4.9 x 106 kgs/sq.m.) and the elongation at
fail of about 45 percent (ASTM D-638). It was found unexpectedly
that the ABS polyblends had about an 100 percent increase in
elongation at failure without loss of tensile strength giving
overall improved toughness.
EXAMPLE 5
HIPS Polyblends Melt Blended with Liquid Polymer
Exa~ple 1 was repeated providing a HIPS polyblend with
about 8.0 percent by weight of diene rubber. Thereafter, 50.0
parts by weight of beads thus produced were melt blended with
1.0 parts of a liquid polymer of a butadiene monomer (Lithene
QH) and 49.0 parts of a polystyrene homopolymer providing a
polyblend with 4 parts by weight of diene rubber, 1 part by
weight (20 weight percent) of a liquid polymer and 95 parts by
weight of homopolymer. An extruded specimen produced therefrom
was found to have a tensile strength at yield of 3,000 psi
(2.1 x 106 kgs/sq.m~), at fail of 3,700 psi (2.6 x 106 kgs/sq.
m.) and an elongation at fail of about 42 percent (ASTM D-638).
It has been found that the HIPS polyblend products of melt
blending at HIPS polyblend with a liquid polymer of a butadiene
monomer unexpectedly provided greatly improved elongation at
fail without loss of tensile strength giving a polyblend of im-
proved overall toughness.
107809~
C-08-12-0334
EXAMPLE 6
ABS Polyblends Melt Blended with Liauid Polymer
~ xample 5 was repeated using the ABS polyblend produced
in Example 2D having 7.21 parts by weight ~weight percent) of
diene rubber in the ABS polyblend. About 66.0 parts of the
polyblend were melt blended with 1.44 parts of liquid polymer
(Lithene QH) and 27.8 parts of SAN polymer providing a polyblend
having 4.77 parts by weight of diene rubber, 1.44 parts by
weight (20 weight percent) liquid polymer. An extruded s?ecimen
produced therefrom had a tensile strength at yield of 6,300
psi (4.4 x 106 kgs/sq.m.), 6,600 psi (4.6 x 106 kgs/sq.m.),
at fail and an elongation at fail of about 43 percent.
EXAMPLES 7-18
HIPS and ABS polyblends were melt blended with varying
amount of liquid polymer as in Examples 5 and 6. The propor-
tions of the formulations are shown below along with test
properties.
- 20 -
1078091
~,-0 8-12-0 334
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-- 21 --
~ 07809~
C-08-12-0334
It is evident.from the.test data that the HIPS poly-
blend control tExample 7) having a 22 percent elongation at
fail and the ABS polyblend control (Example 11) having 25 per-
cent, have the elongation at fail greatly improved by incorpor-
ating a liquid polymer of a conjugated diene monomer thereinwherein about 10 to 50 percent by weight of the diene rubber
is replaced with the liquid polymer.
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