Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
1 336993
POLYPHENYLENE ETHER-HIGH IMPACT POLYSTYRENE 8LENDS
HAVING IMPROVED FLAMMABILITY PERFORMANCE
FIELD OF THE INvENTION
The present invention relates to polymer blend
compositions having improved flammability performance, and
more particularly, to polyphenylene ether-high impact
polystyrene polymer blend compositions having improved
flammability perfor~Ance.
BACKGROUND OF THE INvENTION
Polyphenylene ether resins are known in the art and
exhibit a desirable combination of chemical, physical and
electrical properties over a temperature range of more
than about 650 F, extending from a brittle point of about
-275 F to a heat distortion temperature of about 375 F.
This combination of properties renders polyphenylene ether
resins suitable for a broad ranse of applications.
However, the usefulness of polyphenylene ether resins is
limited in some applications as a consequence of
processability, impact resistance, and chemical
resistance.
As a result, polyphenylene ether resins have been
blended with other polymer resins in order to improve
1 336993
processibility, impact resistance and chemical resistance.
For example, the cizek U.S. patent No. 3,383,435 discloses
blends of polyphenylene ether and o~e or more styrene
resins having improved properties. Add~itionally, the Lee
S U.S. patent No. 3,819,7~1 discloses compositions
comprising a polyphenylene ether and ~ rubber modified
polystyrene resin, which compositio~ provide molded
articles exhibiting improvements in i~pact resistance,
surface appearance and solvent resistance Similarly, the
Lee, Jr. U.S. patent No. 3,835,200 discl~ses compositions
including a polyphenylene ether, a rubber styrene graft
copolymer and a block copolymer of ~ vinyl aromatic
compound and a con~ugated diene, which compositions may be
used to form molded articles having improved toughness
lS without impairing the gloss or surface appearance of the
articles. The Katchman U.S. paten$ No. 3,960,808
discloses polyphenylene ether compositions including a
rubber-modified high impact styrene resin and a
homopolystyrene having a number average molecular weight
between 30,000 and 60,000. Thes~ compositions are
disclosed as having improved surface appearance and a
reduced melt viscosity which facilitates the fabrication
of molded articles having complex configurations and
permits the use of faster molding cycles. Similarly, the
2s Katchman et al U.S. patent No. 3,994,856 discloses
compositions including a polyphenylene ether, a high
impact rubber modified polystyrene resin or a blend of a
high impact rubber modified polystyrene resin and a
homopolystyrene resin, and an elastomeric block copolymer
of a vinyl aromatic compound and a con~usated diene.
These compositions are disclosed as having improved impact
strengths and improved resistance to attack by aggressive
solvents such as gasoline.
1 336993
Additionally, the Sonoda U.S. patent No. 4,617,346,
the Sugio et al U.S. patent NO. 4,5~0,239 and the
Yonemitsu et al U.S. patent N~. ~,887,~46 di~close
- polyphenylene ether resin compositions including rubber
5 modified styrene polymers for improving impact resistance,
heat resistance and the like. Additional polyphenyl~ene
ether and polystyrene resin blends are disclosed in the
Izawa et al U.S. patent No. 3,929,931, the Haaf U.S.
patent No. 4,322,507, the Kuribayashi et al U.S. patent
No. 4,543,391 and the Ueda et al U.S . patent No.
4,599,380.
one 1 imitation which has been experienced in
polyphenylene ether-polystyrene polymer blends is that
their flame retardant properties are insufficient.
15 Particularly, many polyphenylene ether-polystyrene blends
cannot pass flammability tests such as the oxygen index,
UL 94 V or the UL 94 5v tests because of material
dripping. The UL tests are standard test procedures of
the Underwriters Laboratory. The poor flammability
20 performance of such polyphenylene ether-polystyrene blends
prevents the use of such blends in applications which
require improved flammability perforrn~nc~. Thus, a need
exists for polyphenylene ether-polystyrene blends which
exhibit improved flammability perform~nr~.
25 SU~ARY OF THE INvENTION
Accordingly, it is an object of the present invention
to provide polymer blend compositions comprising a
polyphenylene ether resin and a high impact polystyrene
resin. It is an additional ob~ect of the invention to
30 provide polyphenylene ether-high impact polystyrene
polymer blends which exhibit improved flammability
performance over known polyphenylene ether-high impact
polystyrene blends. Another ob~ect of t~e present
~ 336993
invention is to provide polyphenylene ether-high impact
polystyrene polymer blends which are flame retardant. A
specific ob~ect of the present invention is to provide
polyphenylene ether-hish impact polystyrene polymer blends
which exhibit improved flammability performance as
measured by, for example, the oxygen index, UL 94 V and/or
U~ 94 sv tests.
These and additional ob~ects are provided by the
polymer blend compositions according to the present
invention which comprise a polyphenylene ether resin, a
high impact polystyrene resin, a flame retardant, and a
high molecular weight polystyrene resin having a weight
average molecular weight, Mw, greater than about 400,000.
In accordance with the present invention, it has been
discovered that the flammability performance of
polyphenylene ether-high impact polystyrene polymer blends
may be significantly improved by further including a high
molecular weight polystyrene resin having a weight average
molecular weight, Mw, greater than about 400,000.
Inclusion of the high molecular weight polystyrene resin
~ having a weight average molecular weight, Mw, greater than
about 400,000 provides improved flammability performance
to polyphenylene ether-high impact polystyrene polymer
blends already including a conventional flame retardant.
The high molecular weight polystyrene resin is included in
the compositions in an amount sufficient to provide
improved flammability perfor~nce. Preferably, the hiSh
molecular weight polystyrene is included in an amount less
than the amount in which the high impact polystyrene resin
is included in order to retain the advantageous impact
properties of the blends.
These and additional ob~ects and advantages of the
compositions according to the present invention will be
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more fully understood i~ view of the following detailed
description.
DETAILED DESCRIPTION
It has now been discovered that the addition of a
small amount of a high molecular weight polymer to a
polymer blend composition improves the flammability
perfor~Anre of the blend compositions. More particularly,
the polymer blend compositions according to the present
invention having improved flammability performance
comprise a polyphenylene ether resin, a high impact
polystyrene resin, a flame retardant and a high molecular
weight polystyrene resin having a weight average molecular
weight, Mw, greater than about 400,000.
Polyphenylene ether resins adapted for use in the
polymer blend compositions of the present invention
comprise polymers and copolymers having repeating
struc~ural units of the following general formula:
wherein Rl, R2, R3, and R4 each individually represent a
monovalent substituent such as hydrogen, halogen, alkyl,
aryl, alkoxy and other hydrocarbon groups, and n
represents the degree of polymerization. Preferably, n is
at least 20, and more preferably, n is at least 50.
The polyphenylene ether resins suitable for use in
the polymer blend compositions of the present invention
are well known in the art and may ~e prepared by any of a
number of processes known in the art from corresponding
6 1 336993
phenols or reactive derivatives thereof. Examples of
polyphenylene ether resins and methods for their
production are set forth in the Hay U.S. patents Nos.
3,306,874 and 3,306,875 and in the Stamatoff U.S.
patents Nos. 3,257,357 and 3,257,358. Throughout the
Specification and Claims the term "polyphenylene ether"
includes unsubstituted polyphenylene ether, substituted
polyphenylene ether and polyphenylene ether copolymers.
Preferred polyphenylene ether resins adapted for
use in the polymer blend compositions of the present
invention include, but are not limited to, poly(2,6-
dimethyl-1,4-phenylene)ether; poly(2,6-diethyl-1,4-
phenylene)ether; poly(2-methyl-6-ethyl-1,4-phenylene)-
ether; poly(2-methyl-6-propyl-1,4-phenylene)ether;
poly(2,6-dipropyl-1,4-phenylene)ether; poly(2-ethyl-6-
propyl-1,4-phenylene)ether; poly(2,6-dilauryl-1,4-
phenylene)ether; poly(2,6-diphenyl-1,4-phenylene)ether;
poly(2,6-dimethoxy-1,4-phenylene)ether; poly(2,6-
diethoxy-1,4-phenylene)ether; poly(2-methoxy-6-ethoxy-
1,4-phenylene)ether; poly(2-ethyl-6-stearyloxy-1,4-
phenylene)ether; poly(2,6-dichloro-1,4-phenylene)ether;
poly(2-methyl-6-phenyl-1,4-phenylene)ether; poly(2,6-
dibenzyl-1,4-phenylene)ether; poly(2-ethoxy-1,4-
phenylene)ether; poly(2-chloro-1,4-phenylene)ether;
poly(2,6-dibromo-1,4-phenylene)ether; and the like.
The high impact polystyrene resin which is
included in the polymer blend compositions according to
the present invention comprises a combination of
polystyrene and an impact modifier. Specifically, the
high impact polystyrene comprises polymer units derived
from a styrene monomer having the following formula:
r,.
''' ~
7 1 336993
wherein Rl and R2 are selected from the group consisting
of lower alkyl or alkenyl sroups of from, for example, 1
to 6 carbon atoms and hydrogen, each R is selected from
the group consisting of halogen, hydrogen and lower alkyl
or alkenyl groups of from, for example, 1 to 6 carbon
atoms, and n is an integer of from 0 to S. Throughout the
specification and claims the term ~polystyrene resin~
includes unsubstituted polystyrene, substituted
polystyrene and polystyrene copolymer resins. For
example, suitable polystyrene resins include, but are not
1 i m i t ed to, homopolymers of polystyrene,
polychlorostyrene, polymethylstyrene and the like, and
styrene-containing copolymers such as styrene-
acrylonitrile copolymers, copolymers of ethyl vinyl
benzene and divinyl benzene, styrene-acrylonitrile-
methylstyrene terpolymers and the like. The methods for
preparing these polystyrenes are well known in the art.
The polystyrene resin which makes up the high impact
polystyrene resin generally has a weight average molecular
weight, Mw, of about 250,000 or le~-s.
The impact modifier included in the high impact
polystyrene resins according to the present invention
serves to improve the impact properties of the blends.
Impact modifiers are well known in the art and generally
comprise rubber or elastomer compounds. Both natural and
synthet~c rubber and elastomeric compounds are suitable
for use in the high impact polystyrene resin of the
8 1 336993
present invention. Preferred impact modifiers include
homopolymers or copolymers of one or more monomers such as
butadiene, isoprene and ethylene-propylene diene monomers.
Suitable impact modifiers for use in the present invention
include, but are not limited to, hydroxy- and carboxy-
terminated polybutadienes, poly-chlorobutadienes,
copolymers of dienes such as butadiene and isoprene with
various comonomers such as alkyl unsaturated esters, for
example methylmethacrylate, unsaturated ketones, for
example methylisopropenyl ketone, vinyl heterocyclics, for
example vinyl pyridine, and the like. Other impact
modifiers known in the art may also be used accordin~ to
the present invention.
Preferably, the impact modifier and the polystyrene
resin which are combined to form the high impact
polystyrene resin included in the polymer blend
compositions of the present invention are combined prior
to mixing with the other composition ingredients.
Additionally, the polystyrene resin and the impact
modifier are preferably combined in a ratio of at least
3:1 ~y weight to form the high impact polystyrene resin
which is then blended with the polyphenylene ether and the
remaining composition ingredients.
The flame retardant which is included in the polymer
blend compositions of the present invention may comprise
many of the flame retardants which are well known in the
art for polymer systems. Suitable flame retardants
include, but are not limited to, triaryl phosphates such
as triphenyl phosphate and isopropyl triphenyl phosphate,
and brominated aromatic compounds such as
decabromobiphenyl, pentabromophenyl, pentabromotoluene,
hexabromobenzene, decabromodiphenyl carbonate and
tetrabromothalic anhydride.
1 336993
The high molecular weight polystyrene resin which is
included in the polyme~ blend compositions of the present
invention has a weight average molecular weight, Mw,
greater than about 400,000. The high molecular weight
S polystyrene resin provides the polymer blend compositions
with improved flammability performance. Specifically, the
high molecular weight polystyrene resin improves the
perfor~nce of polyphenylene ether-high impact polystyrene
polymer blend compositions in the oxygen index, UL 94 V
and/or UL 94 5v tests. In a preferred embodiment, the
high molecular weight polystyrene resin has a weight
average molecular weight, Mw, greater than 600,000. The
high molecular weight polystyrene resin may be linear or
branched. At least a small degree of branching may
improve certain properties of the compositions, for
example, viscosity, and may reduce the amount of high
molecular weight polystyrene required to provide improved
flammability performance in a blend composition.
Additionally, the high molecular weight polystyrene resin
preferably comprises a polystyrene homopolymer or a
polystyrene copolymer formed from less than 10 weight
percent, and more preferably less than 5 weight percent,
of a non-styrene monomer. The non-styrene monomer
generally comprises a functional monomer which provides
the high molecular weight polystyrene with a degree of
branching structure.
The amounts of polyphenylene ether resin, high impact
polystyrene resin, flame retardant and high molecular
weight polystyrene resin included in the polymer blend
compositions of the present invention may be varied
depending on the specific nature of the high molecular
weight polystyrene resin and on the end use of the polymer
blend composition. The high molecular weight polystyrene
resin is included in an amount sufficient to provide the
- 1 336993
blends with improved flammability perform~nce. As will be
apparent to one skilled in the art, flammability
performance may be measured in various manners, including,
fo~ example, the oxygen index, UL 94 V and UL 94 sV tests.
The high molecular weight polystyrene resin is preferably
included in the blends in an amount less than the amount
in which the high impact polystyrene resin is included.
It is preferred that the high impact polystyrene is
included in a greater amount than the high molecular
weight polystyrene in order to retain the advantageous
properties of the polyphenylene-polystyrene blends.
Generally, the high molecular weight polystyrene resin is
included at least in an amount of about one weight percent
in order to provide the polymer blend composition with the
improved flammability performance. Moreover, no more than
about 10 weight percent of the high molecular weight
polystyrene is usually re~uired in the blends in order to
provide improvements in flammability performance.
Preferred amounts of the high molecular weight polystyrene
are from about 3 to about 8 weight percent. It is
_ believed that relatively lower amounts of the high
molecular weight polystyrene may be used if the high
molecular weight polystyrene comprises at least a small
degree of br~nching, while, if the high molecular weight
polystyrene is linear, relatively greater amounts may be
necessary to provide the improved flammability
performance.
The polymer blend compositions according to the
present inVentioQ also preferably comprise from about 5 to
about 90 weight percent of the polyphenylene ether resin,
from about 5 to about 90 weight percent of the high impact
polystyrene resin, and from about 0.1 to about 30 weight
percent of the flame retardant. In additionally preferred
embodiments, the polymer blend compositions according to
1 336993
the present invention comprise from about 25 to about 70
weight percent of the polyphenylene ether resin, from
about 25 to about 70 weight percent of the high impact
polystyrene resin, from about 1 to about 20 weight percent
S of the flame retardant and from about 3 to about 8 weight
percent of the high molecular weight polystyrene resin.
The method of forming the polymer blend composition
is not critical and prior art blending techniques are
suitable. As set forth above, a preferred method
comprises first blending the polystyrene resin and the
impact modifier and then blending the resultant high
impact polystyrene resin with the polyphenylene ether and
other components included in the polymer blend
composition.
Additionally, conventional amounts of conventional
additives for processibility, stability and the like may
be included in the polymer blend compositions of the
present invention. Fillers and/or reinforcing fillers may
also be included in the polymer blend compositions,
examples of which include powders, beads, whiskers, fibers
or platelets, of metals, for example aluminum, bronze,
iron and nickel, and/or nonmetals, for example carbon,
calcium silicate, asbestos, titanium dioxide, talc, clay,
glass flakes, glass fibers and the like.
The following Examples are provided to illustrate
specific embodiments of the present invention.
EXAMPLE 1
In accordance with the present invention, polymer
blend compositions were prepared including a polyphenylene
ether resin, a high impact polystyrene resin, a flame
retardant and a high molecular weight polystyrene. The
amounts, in weight percents, of the components included in
the compositions are set forth in Table 1. The flame
1 336993
12
retardant included in the compositions of this Example
comprised triphenyl phosphate. The high molPc~ r weight
polystyre~e comprised 2 commercially available, linear
high molecular weight polystyrene, celukavit S suppli~ed by
C.D.F. Chimie, having a weight average molecular weight,
Mw, of approximately 6 x 10 . The compositions of this
Example further included approximately 1.4 total weight
percent of additional additives comprising a butyl hydroxy
toluene antioxidant, an ethylene oxide/propylene oxide
copolymer lubricant and an octyldiphenyl phosphite
stabilizer. As set forth in Table 1, composition A did
not include any of the high molecular weight polystyrene
resin while compositions B-F included increasing amounts
of the high molecular weight polystyrene resin,
respectively. In~ection molded bars of the compositions
were subjected to the UL 94 5v and oxygen index tests in
order to determine flammability performA~c~. In this and
the following examples the UL tests were conducted
according to the standards of Underwriters Laboratory.
The oxygen index test was performed according to ASTM D-
2863. Various physical properties ~ the compositio~s
were also measured including the Not~hed Izod Impact
Strength according to ASTM D-256, method A, the Mobay
viscosity according to a method substantially similar to
ASTM D-3835 at 550F and the tensile properties according
to ASTM D-639. The results of these tests and
measurements are also set forth in Table 1. In the UL 94
sv tests set forth in Table 1, F-5 indicates that the
sample failed the test during the fifth ignition, that i8,
the sample dripped during the fifth ignition.
Compositions B-F show improved fl~mmability perform~nce as
measured by the oxygen index test, while compositions D-F
also exhibited improved flammability performance as
measured by the UL 94 sV test. The res~lts set forth in
-
1 336993
13
Table 1 further indicate that the physical properties of
the polymer blend compositions of the present invention,
for example notched Izod impact strength, viscosity and
tensile strength, modulus and elongatio~, ~ere not
unreasonably affected by the i~clusion of the high
molecular weight polystyrene resin in the compositions as
compared with the Comparative Composition A.
14 l 336993
TABLE 1
ComPonent, wt % A B C D E F
F~ Jh ~ Ether 41.6 41.6 41.6 41.6 41.6 41.6
High Impact 41.6 39.1 38.3 37.5 36.6 35.0
F~ Resin
Flame Retardant 15.4 15.4 15.4 15.4 15.4 15.4
High MDI~ ~ r --- 2.5 3.3 4.1 5.0 6.6
Weight F~ JI~
Additives 1.4 1.4 1.4 1.4 1.4 1.4
UL 94 5V (.125" thick) F-5 F-5 F-5 PASS PASS PASS
IZOD IMPACT STRENGTH, 8.4 8.2 8.0 8.2 7.4 7.5
ft-lbs/in
SPECIFIC GRAVITY 1.099 1.1001.100 1.100 1.101 1.101
OXYGEN INDEX (%) 28.5 30.0 31.0 31.5 31.5 33.0
MOBAY VISCOSITY, 100 SEC.-1 3745 4123 4062 4056 4372 4448
(550F) 500 SEC.-1 1772 1997 2003 2008 2138 2218
1000 SEC.-1 1284 1461 1477 1483 1572 1644
TENSILE ST., PSI 5555 5823 5940 5850 6250 6090
MOD., PSI~105 3.5 3.5 3.6 3.3 3.4 3.5
ELONG., % 62 59 62 70 60 59
-
1 336993
EXAMPLE 2
Polymer blend compositions were prepared comprising a
polyphenylene ether, a high impa~ct polystyrene resin, a
flame retardant and a high molecular weight polystyrene
resin in a manner similar to that set forth in Example 1.
The amounts of the components, in weight percents, are
indicated in Table 2. The flame retardant included in the
polymer blend compositions comprised triphenyl phosphate.
The high molecular weight polystyrene comprised the linear
Celukavit S set forth in Example 1. Compositions A and B
did not include a high molecular weight polystyrene resin
in accordance with the present invention. Composition A
of this Example also included approximately 2 total weight
percent of additives comprising a butyl hydroxy toluene
antioxidant, an ethylene oxide/propylene oxide copolymer
lubricant, and an octyldiphenyl phosphite stabilizer as
described in Example 1 and a substituted hydroxyphenyl
benzotriazol UV stabilizer. Compositions B-D included
approximately 2.5 total weight percent of additives
comprising the aforementioned antioxidant, lubricant and
phosphite stabilizer. ~njection molded bars of these
compositions were sub~ected to the UL 94 5v test and other
tests for measuring physical prcperties as set forth in
Example 1. The compositions wer- also subjected to the
heat distortion temperature test accordins to ASTM D-696.
The results of these tests are set forth in Table 2.
Composition D relating to a preferred composition of the
present invention including sreater than 3 percent by
weight of the high molecular weight linear polystyrene
successfully passed the UL 94 5v test. Additionally, the
physical properties of composition D were not adversely
affected by the inclusion of the high molecular weight
polystyrene.
16 l 336993
TABLE 2
ComPonent,wt % A B C D
Pol~lJh~ ~lene Ether 32.3 32.2 32.2 32.2
HighImpact 52.8 52.5 50.0 48.3
Poly~ly~ Resin
Flame Retardant 12.8 12.7 12.7 12.7
High Molecular -- -- 2.5 4.2
Weight Poly~lyrl
Additives 2.1 2.6 2.6 2.6
UL 94 5V (.125" thick) F-5 F-5 F-5 PASS
IZOD IMPACT STRENGTH, 4.0 4.2 3.8 3.9
ft-lbs/in
HDT, F 155 154 156 156
MOBAY VISCOSITY, 100 SEC.-13156 3132 3666 3227
(550F) 500 SEC.-1 1484 1478 1668 1607
1000 SEC.-1 1072 1070 1188 1191
TENSILE ST., PSI 5460 5180 5180 5430
MOD., PSIx105 3.5 3.6 3.5 3.4
ELONG., % 40 37 37 51
~ 33699~
17
EXAMPLE 3
~ olymer blend compositio~s according to the present
invention were prepared, the components of which are set
forth in weight percent in Table 3. Composition A of this
Example did not include a high molecular weight
polystyrene. The flame retardant comprised triphenyl
phosphate while the high molecular weight polystyrene
comprised the linear Celukavit S. Compositions A-C all
included approximately 1 total weight percent of the
aforementioned antioxidant, lubricant and phosphite
stabilizer. In~ection molded bars of the polymer blend
compositions were subjected to the UL 94 sv test and to
measurements of the notched Izod impact, Mobay viscosity
and tensile strength, modulus and elongation as set forth
in Example 1, the results of which are set forth in Table
3. The results in Table 3 also indicate that the physical
properties of composition C were not adversely affected by
the high molecular weight polystyrene resin.
-
18 l 336993
TABLE 3
Component~wt % A B C
Polyphenylene Ether 41.8 41.8 41.8
High Impact 47.1 44.4 42.7
Pol~ly~ e.,e Resin
FlameRetardant 9.8 9.8 9.8
~igh Molecular -- 2.7 4.4
Weight Poly~lyrene
Additives 1.3 1.3 1.3
UL 94 5V (.125" thick) F-4 F-5 Pass
Burn Time, sec. dripped dripped 10
IZOD IMPACT STRENGTH, 5.0 5.2 5.3
ft-lbs/in
I~DT, F 184 186 190
MOBAY VISCOSITY, 100 SEC.-15024 5347 5409
(550F) 500 SEC.-1 2450 2536 2667
1000 SEC.-1 1799 1944 1967
TENSILE ST., PSI 7415 7695 7850
MOD., PSIx105 3.5 3.5 3.6
ELONG., % 30 29 31
19 1 336993
EXAMPLE 4
Polymer blend compositions were prepared in this
Example according to the present invention, the amounts of
the components of which are set forth in weight percents
S in Table 4. The flame retardant comprised triphenyl
phosphate and the high molecular weight polystyrene
comprised the linear Celukavit S. The compositions also
included approximately 1 total weight percent of additives
comprising the aforementioned antioxidant, a
trinonylphenyl phosphite stabilizer and a magnesium oxide
filler. Both solid and foamed samples of the polymer
blend compositions were subjected to the UL 94 sv test.
The foamed samples were prepared using a polyolefin
~ blowing agent (Nortech 1226 supplied by Enron Chemical
company) and had a 10 percent weight reduction as compared
with the solid samples. The results of the UL 94 sv tests
are set forth in Table 4. These results indicate that the
solid szmples of the compositions according to the present
invention, B-D, passed the UL 94 sv tests with burn times
of 7, 8 and 10 seconds, respectively, while the solid
sample of composition A not including the high molecular
weight polystyrene failed the UL 94 sv test at the fifth
isnition. Additionally, the foamed sample of composition
D according to the present invention also passed the UL 94
sv test.
- 20 l 336993
TABLE 4
Component,wt % A B C D
Polyphenylene Ether 41.5 41.5 41.5 41.5
High Impact
Polystyrene Resin 45.0 42.4 40.7 38.1
Flame Retardant 12.5 12.5 12.5 12.5
High Molecular -- 2.6 4.3 6.9
Weight Polystyrene
Additives 1.0 1.0 1.0 1.0
UL94 5V, SOLID, (.150" thick) F-5 Pass Pass Pass
BURN TIME dripped 7 8 10
UL 94 5V, FOAMED, (.150" thick) F-5 F-5 F-5 Pass
BURN TIME dripped dripped dripped 10
21 ~ 336993
EXAMPLE S
Polymer blend compositions were prepared in this
Example according to the present invention, the components
of which are set forth in weisht percents in Table 5. The
flame retardant included in these compositions comprised
triphenyl phosphate. Composition A did not include a high
molecular weight polystyrene resin. Compositions B-G
included high molecular weight polystyrene resins
comprising branched networks. These high molecular weight
polystyrene resins were prepared by incorporating small
amounts of di- or tri-functional monomers as the
polystyrenes were formed. The functional monomer was
added continuously at a low level in order to maintain an
extremely low level of monomer during polymer synthesis.
Compositions B-D included a high molecular weight
polystyrene copolymer resin formed from 99.3 percent
styrene monomer and 0.7 percent diallyl maleate monomer.
The high molecular weight polystyrene formed a gel in THP
and toluene solvents so the approximate molecular weight
could not be determined by liquid chromatography.
Compositions E-G included a high molecular weight
polystyrene copolymer resin prepared from 99.9 percent
styrene monomer and 0.1 percent divinyl benzene monomer.
The high molecular weight polystyrene copolymer resin had
a weight average molecular weight, Mw, of approximately
670,000 as measured by liquid chromatography in toluene
solution with linear polystyrene standards. The
- compositions of this Example also included approximately 1
weight percent of the additives set forth in Example 3.
In~ection molded bars of the compositions of this Example
were sub~ected to the UL 94 5V test and to measurement of
various physical properties, the results of which are set
forth in Table 5. AS may be observed from the results set
-
22 ~ 336993
forth in Table 5, comparative composition A not including
a high molecular weight polystyrene did not pass the UL 94
5v test while compositions B-G according to the present
invention successfully passed the UL 94 5v tes~s with burn
times ranging from 9 to 14 seconds. The additional
results set forth in Table S indicate that the physical
properties of the compositions according to the present
invention were not adversely affected by the high
molecular weight polystyrene as compared with the
properties of comparative composition A.
23 1 336993
TABLE S
ComPonent,wt % A B C D E F G
Polyphenylene Ether 41.8 41.8 41.8 41.8 41.8 41.8 41.9
High Impact
Polystyrene Resin 47.1 45.3 44.4 43.5 44.4 43.5 42.7
Flame Retardant 9.8 9.8 9.8 9.8 9.8 9.8 9.8
High Molecular
Weight Polystyrene -- 1.8 2.7 3.6 2.7 3.6 4.4
Additives 1.3 1.3 1.3 1.3 1.3 1.3 1.3
UL 94 5V (.125" thick) F-5 Pass Pass Pass Pass Pass Pass
Burn Time, sec. drippe 9 9 9 14 11 10
IZOD IMPACT STRENGTH, 4.7 4.6 4.9 4.5 4.9 4.5 4.6
ft-lbs/in
MOBAYVISCOSITY, 100 SEC.-l 5057 5108 4599 5081 4612 4875 5161
(550F) 500 SEC.-1 2403 2542 2270 2555 2269 2464 2552
1000 SEC.-1 1744 1882 1675 1900 1671 1837 1884
TENSILE ST., PSI 7945 7967 7880 8250 7740 7915 8135
MOD., PSIx105 3.3 3.2 3.4 3.4 3.4 3.4 3.5
ELONG., % 29 29 26 24 30 29 26
24
1 336993
EXAMPLE 6
Polymer blend compositions were prepared in this
Example according to the present invention, the components
of which are set forth by weight percent in Table 6. The
flame retardant included in the compositions of this
Example comprised triphenyl phosphate. The high molecular
weight polystyrene resin comprised a copolymer formed from
99.6 percent styrene monomer and 0.4 percent allyl
methacrylate monomer. The high molecular weight
polystyrene copolymer resin had a weight average molecular
weight, Mw, of approximately 856,000 as measured by the
chromatography techniques described in Example 5. The
compositions of this Example also included approximately 1
total weight percent of the aforementioned antioxidant,
lS lubricant and octyldiphenyl phosphite stabilizer.
In~ection molded bars of these polymer blend compositions
were sub-jected to the UL 94 5v test and to measurements of
various physical properties, the results of which are set
forth in Table 6. As may be observed from Table 6, the
compositions B-D according to the present invention pas~ed
the UL 94 5v tests with burn times of from 12 to 14
seconds while comparative composition A not including a
high molecular weight polystyrene resin did not pass the
UL 94 5v test. The remaining results set forth in Table 6
indicate that the various physical properties measured
were not adversely affected by the inclusion of the high
molecular weight polystyrene resins.
1 336993
TABLE 6
Component,wt % A B C D
Polyphenylene Ether 41.8 41.8 41.8 41.8
High Impact
Polystyrene Resin 47.1 44.4 43.5 42.7
Flame Retardant 9.8 9.8 9.8 9.8
High Molecular
Weight Polystyrene -- 2.7 3.6 4.4
Additives 1.3 1.3 1.3 1.3
UL 94 5V (.125" thick) F-5 Pass Pass Pass
BurnTime, sec. dripped 14 12 13
IZOD IMPACT STRENGTH, 5.6 5.7 5.6 5.6
~-lbs/in
HDT, F 184 188 186 190
MOBAYVISCOSITY, 100 SEC.-1 4914 5431 5767 5651
(550F) 500 SEC.-1 2496 2721 2992 2771
1000 SEC.-l 1964 2021 3149 2038
TENSILE ST., PSI 7535 8090 8325 8375
MOD., PSIx105 3.5 3.5 3.7 3.6
ELONG., % 32 27 26 27
1 336993
26
The preceding Examples are set forth to illustrate
specific embodiments of the invention and are not intended
to limit the scope of the compositions of the present
invention. Additional embodiments and advantages within
S the scope of the claimed invention will be apparent to one
of ordinary skill in the art.
