Note: Descriptions are shown in the official language in which they were submitted.
~ ,~ 8 CH 2419
This invention relates to thermoplastic molding
compositions of a polyphenylene ether resin, a styrene resin,
- and a radial teleblock copolymer of a vinyl aromatic compound
and a saturated rubber. The compositions of this invention
provide molded articles having good mechanical properties,
including improved impact resistance. Reinforced and flame-
retardant compositions are also provided.
The polyphenylene ether resins are a family of
engineering thermoplastics that are well known to the polymer
art. These polymers may be made by a variety of catalytic
and non-catalytic processes from the corresponding phenols
or reactive derivatives thereof. By way of illustration,
certain of the polyphenylene ethers are disclosed in Hay,
U.S. 3,306,874 dated February 28, 1967 and 3,306,875 dated
February 28, 1967; and in Stamatoff, U.S. 3,257,357 dated
June 21, 1966 and 3,257,358 dated June 21, 1966. In the Hay
patents, the polyphenylene ethers are prepared by an
oxidative coupling reaction comprisiny passing an oxygen-
containing gas through a reac-tion solution of a phenol and
a metal-amine complex catalys-t. Other disclosures relating
to processes for preparing polyphenylene ether resins,
including graft copolymers of polyphenylene ethers with
styrene type compounds, are ~ound in Fox, U.S. 3,356,761
dated December 5, 1967; Sumitomo, U.K. 1,291,609; Bussink
et al., U.S. 3,337,499 dated August 22, 1967; Blanchard et al.,
U.S. 3,219,626 November 23, 1965; Laakso et al., U.S.
3, 34~
3,342,892 dated September 19, 1967; Borman, U.S. ~,~4,1~
dated September 26, 1967; ~lori et al, U.S. 3,384,619 dated
May 21, 1968; Faurote et al., U.S. 3,440, 217 dated April
22, 1969; and disclosures relating to metal based catalysts
which do not include amines, are known from patents such as
~ieden et al., U.S. 3,442,885 dated May 6r 1969 (copper-
- 1 ~
~ ~ 8CH-2419
amidines); Nakashio et al, U.S. Patent 3,573,257 dated March 30,
1971 (metal-alcoholate or -phenolate); Xobayashi et al, U.S.
Patent 3,455,880 dated July 15, 1969 (cobalt chelates); and
the like. In the Stamatoff patents, the polyphenylene ethers
are produced by reacting the corresponding phenolate ion with
an initiator, such as peroxy acid salt, an acid peroxide, a
hypohalite, and the like, in the presence of a complexing
agent. Disclosures relating to non-catalytic processes,
such as oxidation with lead dioxide, silver oxide, etc., are
described in Price et al, U.S. Patent 3,382,212 dated May 7, 1968.
Cizek, U.S. Patent 3,383,435 dated May 14, 1968 disclosures
polyphenylene ether-styrene resin compositions.
The processing of polyphenylene ether resins on
injection molding and extrusion equipment is enhanced when the
polyphenylene ethers are combined with styrene resins, e.g.,
crystal homopolystyrene or rubber modified high-impact poly-
styrenes. These polymers are combinable in a wide range of
; proportions, e.g., from 1 to 99 parts of polyphenylene ether
and from 99 to 1 parts of styrene resin. Compositions com-
prising from 10 to 60 parts of polyphenylene ether and 90 to
- 40 parts of styrene resin offer an especially wide range of
desirable design properties.
Such combinations are disc]osed in Cizek, U~S.
Patent 3,383,435 dated May 14, 1968. The thermoplastic
composition disclosed in Cizek can include a rubber-modified
high-impact styrene resin, as well as a homopo]ystyrene.
High-impact styrene resins are especially useful in providing
polyphenylene ether compositions which possess good resistance
to impact.
It is disclosed in copending, commonly assigned
Canadian patent application Serial No. 274,750 filed
- 2 -
~ 8 CH 2419
March 25, 1977 that compositions of a polyphenylene ether
resin, a styrene resin, and a radial telebloclc copolymer of
a vinyl aromatic compound and a conjugated diene, e.g., a
styrene-butadiene radial teleblock copolymer, provide molded
articles of good impact strength.
It has now been surprisingly discovered that when
compositions are prepared from a polyphenylene ether resin, a
styrene resin, and a hydrogenated radial teleblock copolymer
of a vinyl aromatic compound and a saturated rubber, the re-
sulting compositions provide molded articles of improved
surface gloss. The radial hydrogenated teleblock copolymers
employed in the present invention have been found to be
compatible with, and effective for, compositions of relatively
high polyphenylene ether resin content, e.g., 50 parts by
weight or more, and low molecular weight crystal polystyrene,
as well as compositions of relatively low polyphenylene ether
resin content, e.g., 35 parts by weight or less, and high-
impact polystyrene.
As used herein, the term "hydrogenated radial tele-
block copolymer" refers to branched polymers having segments,
or blocks, which are comprised of a saturated rubber, blocks of
a vinyl aromatic polymer, and a coupling agent. More particu-
larly, in the copolymer structure r several chains of the
rubber, usually three or more, e~tend from a coupling agent,
with each chain terminating at its other end with a block of
the vinyl aromatic polymer. It is generally believed that
incompatibility of the block segments in the radial teleblock
copolymer promotes the formation of a two-phase system with
blocks of the vinyl aromatic polymer coalescing to form
discrete regions, or "domains". These domains simulate the
effect of cross-links between the chains of elastomer, and a
branched elastomeric network is thus formed comprising blocks
~97~ 8CH-2419
of a saturated rubber, blocks of vinyl aroma-tic polymer, and
a coupling agent.
Radial teleblock copolymers are known in the art.
For instance, detailed descriptions of these materials are
given by Marrs et al in ADHESIVES AGE, December, 1971, pp.
15-20 and by Haws et al. in RUBB~R WORLD, January, 1973, pp.
27-32. Hydrogenation of radial teleblock copolymers is
also known in the art.
It is, therefore, a primary object of this
invention to provide improved compositions based on poly-
phenylene ether resins, styrene resins, and hydrogenated
radial teleblock copolymers.
Another object of this invention is to provide
molding compositions and molded articles based on polyphenylene
ether resins, styrene resins, and hydrogenated radial teleblock
copolymers that have improved surface gloss.
Still another object of this invention is to
provide molding compositions and molded articles based on
polyphenylene ether resins, styrene resins, and hydrogenated
radial teleblock copolymers that have improved impact strength.
It is also an object of this invention to provide
the above-described, improved molding compositions in reinforced
and/or flame-retardant embodiments.
According to the present invention, there are provided
thermoplastic molding compositions which comprise an intimate
admixture of:
(i) a polyphenylene ether resin;
(ii) a styrene resin; and
(iii) a hydrogenated radial teleblock
copolymer of a vinyl aromatic compound,
a saturated rubber, and a coupling agent.
- 4 -
8 CH 2~19
Within the invention broadly described above, the
styrene resin component (ii) can be ei-ther homopolystyrene
or a rubber-modified high-impact polystyrene. The radial
teleblock copolymer (iii) is preferably a branched copolymer
of styrene and hydrogenated rubber containing a relatively
small, effective amount of a coupling agent selected from
~M
among epoxidized-polybutadiene (e.g., Oxiron 2000 or Oxiron ~ -~
2001), SiC14, or mixtures thereof.
The polyphenylene ether resin (i) is preferably
one of a family having repeating units represented by the
formula: -
Q
wherein the oxygen ether atom of one unit is connected to the `
benzene nucleus of the next adjoining unit, n is a posi-tive
integer and is at least 50, and each Q is a monovalent sub-
stituent selected from the group consisting of hydrogen,halogen, hydrocarbon radicals free of a tertiary alpha-carbon
atom, halohydrocarbon radicals having at least two carbon
atoms between the halogen atom and the phenyl nucleus,
hydrocarbonoxy radicals, and halohydrocarbonoxy radicals ~`
having at least two carbon atoms between the halogen atom
and the phenol nucleus.
Examples of polyphenylene ethers corresponding to
the above formula can be found in the above-re~erenced patents
of Hay and Stamatoff.
For purposes of the present invention an especially
preferred family of polyphenylene ethers includes those having
8 CH 2419
alkyl substitution in the two positions ortho to the oxygen
ether atom, i.e. those of the above formula wherein each Q
is alkyl, most preferably having from 1 to 4 carbon atoms.
Illustrative members of this class are: 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; and the like.
The most preferred polyphenylene ether resin is poly(2.6-
dimethyl-1,4-phenylene)ether, preferably having an intrinsic
viscosity of about 0.5 deciliters per gram as measured in
chloroform at 30~.
The preferred styrene resins (ii) will be those
having at least 25% by weight of repeating units derived from
a vinyl aromatic monomer of the formula:
1 2
CR = CHR
~II) ~ ~ ~ R3
R6
wherein Rl and R2 are se]ec-ted from the group consisting of
hydrogen and lower alkyl or alkenyl groups of from 1 to 6
carbon atoms; R3 and R4 are selected from the group consisting
of chloro, bromo, hydrogen, and lower alkyl groups of from
1 to 6 carbon atoms; and R5 and R6 are selected from the
group consisting of hydrogen and lower slkyl and alkenyl
groups of from 1 to 6 carbon atoms or R5 and R6 may be
concatenated together with hydrocarbyl groups to form a
naphthyl group. These compounds are free of any substituent
that has a tertiary carbon atom.
~ ' ~1197~2 8 CH 2419
~:`. Specific examples of vinyl aromatic monomers include
styrene, chlorostyrene, ~ -methylstyrene, vinyl xylene,
divinylbenzene, and vinyl naphthalene.
..~
~ The vinyl aromatic monomer may be copolymerized .~
:i
i with materials such as those having the general formula:
.~ 8
;. R
~ R - C(H)n ~ ~ - C ~ ~ (CH2)m
..... .
; ~ , .
wherein the dotted lines each represent a single or a double
carbon to carbon bond; R7 and R8 taken together represent a
I C)
C--O--C linkage; R is selected from the group consis~ting of
: hydrogen, vinyl, alkyl of from 1 to 12 carbon atoms, alkenyl of
; from 1 to 12 carbon atoms, alkylcarboxylic of from 1 to 12 ~ :.
carbon atoms, and alkenylcarboxylic of from 1 to 12 carbon ~.
~ ~ .
atoms; n is 1 or 2, depending on the position of the carbon- ;
carbon double bond; and m is an integer of fxom 0 to about 1~. . .
li Examples include maleic anhydride, citraconic anhydride, ita- :
;',,,~! 20 conic anhydride, aconitic anhydride, and the like.
,:
i Merely by way of illustration, the styrene resins
(ii) include homopolymers such as polystyrene and monochloro~
; polystyrene, the modified polystyrenes, such ~s rubber~ ~:
" ~
modified, high-impact polystyrene, and the styrene containing
i copolymers, such as the styrene-acrylonitrile copolymers,
~! styrene-butadiene copolymers, styrene~acrylonitrile-o~ kyl
.. styrene copolymers, styrene-acrylonitrile-butadiene copolymers, :,,
~- poly-~ -methyl-styrene, copolymers of ethylvinylbenzene, and
divinylbenzene, styrene-maleic anhydride copolymers, styrene- ~.
i 30 butadiene-styrene block copolymers and styrene-butadiene
block copolymers, and styrene-butadiene-styrene maleic
~ anhydride block copolymers. -
- 7 -
~ 8 C~ 2419
The styrene-maleic anhydride copolymers are
described in U.S. 3,336,267 dated August 15, 1967 and U.S.
2,769,804 dated November 6, 1956.
Especially preferred styrene resins are homopoly-
styrene and rubber-modified high-impact polystyrene resins,
i.e., those which have been modified by natura] or synthetic
polymeric materials which are elastomers at room temperature,
e.g., 20 to 25C~, such as polystyrene resins containing poly-
butadiene or ruhbery styrene-butadiene copolymers.
A preferred high-impact polystyrene is FG 834,
available from Foster-Grant Co., which is a rubber-modiEied
high-impact polystyrene containing about 8% polybutadiene
rubber. A preferred low molecular weight homopolystyrene is
KPTL-5, commercially available from Arco Polymers, Inc.,
Pittsburgh, Pa., having a number average molecular weight of
about 40,000. A preferred homopolystyrene of relatively high
molecular weight is DYL-8G, with a number average molecular
weight of about 150,000, also available from Arco.
Radial teleblock copolymers are available
commercially or can be prepared by following the teachings of
the prior art. As an illustration, they can be made by poly-
merizing conjugated dienes, e.g., butadier~e, and vinyl
aromatic compounds, e.g., styrene in the presence of an organo-
metallic initiator, e.g., n-butyllithium, to produce copolymers
which contain an ac-tive metal atom, such as lithium, on one
end of each of the polymer chains. These metal atom-terminated
polymers are then reacted wi-th a coupling agent which has at
least three active sites capable of reacting with the carbon-
metal atom bonds on the polymer chains and replacing the metal
atoms on the chains. This results in polymers which have
relatively long branches which radiate from a nucleus formed
by the poly~functional coupling agent. Such a method of
-- 8
~ 8CH 2419
.'~
preparation is described in detail in Zelinski et al., U.S.
3,281,383 dated October 25, 1966.
The coupling agents for radial teleblock copolymers
~~ can be chosen from among polyepoxides, polyisocyanates, poly-
^~ imines, polyaldehydes, polyketones, polyanhydrides,
polyesters, polyhalides and the like. These materials can
contain two or more types of functional groups, such as the
;:;
combination of epoxy and aldehyde groups or isocyanate and
halide groups. The coupling agents are described in detail
- 10 in the above-mentioned U.S. 3,281,383 dated October 25, 1966.
The conjugated dienes of radial teleblock
copolymers include compounds such as 1,3-butadiene, isoprene,
2,3-dimethyl 1,3-butadiene, 1,3-pentadiene, 3-butyl-1,
.
3-octadiene, and the like.
The vinyl aromatic polymers may be prepared from
~i
- vinyl aromatic compounds of Formula II. They include styrene,
l-vinylnaphthalene, 2-vinylnaphthalene, and the alkyl, cyclo-
alkyl, aryl, alkaryl, and aralkyl derivatives thereof.
Examples include 3-methylstyrene, 4-n-propylstyrene,
4-cyclohexylstyrene, 4-dodecylstyrene, 2-ethyl-4-benzylstyrene,
, !
4-p-tolystyrene, 4-(4-phenyl-n-butyl) styrene, and the like.
I ~ .
Hydrogenation of radial teleblock copolymers to
; form the hydrogenated radial teleblock copolymers (iii) can;
be carried out by any of several known procedures. See by
i way of illustration, de Vault, U.S. 3,696,088.
In preferred compositions, the hydrogenated radial
teleblock copolymer will be a radial teleblock copolymer of
styrene and a saturated rubber, with terminal blocks derived
from styrene, and a coupling agent selected from epoxidized
polybutadiene, SiC14, or mixtures thereof. Especially preferred
epoxidized polybutadiene coupling agents are available commer-
., .
.~ _ g _
X
.
' ' ' ` "'
~ CEi 2~19
,"
cially under the trade names Oxiron 2000 and O~iron 2001.
The molecular weight of the hydrogenated radial
teleblock copolymer and the ratios of the co-monomers thereof
can vary broadly. In preferred embodiments the molecular
weight of the hydrogenated radial teleblock copolymer will be
from about 75,000 to about 350,000 and will comprise from 1
to 45 parts by weight of the vinyl aromatic compound and from
99 to 55 parts by weight of the saturated rubber, based on
the weight of the radial teleblock copolymer. The amount of
coupling agent in the copolymer will depend on the particular
agent and the amount of organometal:Lic initiator used. Gen-
erally, relatively small amounts of coupling agent, e.g.,
from 0.1 to l part by weight per 100 parts of resin are em-
ployed.
Preferred hydrogenated radial teleblock copolymers
. r~
include Solprene 502 and 512 (containing about 70 parts by
weight of hydrogenated butadiene units and about 30 parts
by weight of styrene units), which are available commercially
from Philips Petroleum Co., Stowe, Ohio. These ma-terials
also include a relatively ~linor amount of a coupling agent,
e.g., less than l part by weight of a coupling agent per
100 parts by weight of copolymer.
Components (i), (ii), and (iii) are combinable
in a fairly wide range of proportions. Preferably, the compo-
sitions of this invention will comprise from about 10 to about
65 parts by weight of polyphenylene ether resin (i), from
about 90 to about 35 parts by weight of styrene resin (ii),
and from about 1 to about 25 parts by weight of hydrogenated
radial teleblock copolymer (iii), based on the total weight of
the composition.
The compositions of the invention can also include
other ingredients, such as flame-retardants, extenders,
processing aids, pigments, stabilizers, and the like, for
-- 10 --
~ 8 CH 2419
their conventionally employed purposes. Reinforcing fillers,
in amounts sufficient to impart reinforcement, can be used,
such as aluminum, iron or nickel, and the like, and non-metals,
such as carbon filaments, silicates, such as acicular calcium
silicate, asbestos, titanium dioxide, potassium titanate and
titanate whiskers, glass flakes and fibers, and the like.
It is to be understood that, unless the filler adds to the
strength and stiffness of the composition, it is only a filler
and not a reinforcing filler as contemplated herein. In
particular, the reinforcing fillers increase the flexural
strength, the flexural modulus, the tensile strength and the
heat distortion temperature.
Although it is only necessary to have at least a
reinforcing amount of the reinforcement present, in general,
the combination of components (i), (ii), and (iii) will
comprise from about 10 to about 90 parts by weight and the
filler will comprise from about 10 to about 90 parts by weight
of the total composition.
In particular, the preferred reinforcing fillers
are of glass, and it. is preferred to use fibrous glass fila-
ments comprised of lime-aluminum borosilicate glass that is
relatively soda free. This is known as "E" glass. However,
other glasses are useful where electrical properties are not
so important, e.g., the low soda glass known as "C" glass.
The filaments are made by standard processes, e.g., by steam
or air blowing, by flame blowing, or by mechanical pulling.
The preferred filaments for plastics reinforcement are made
by mechanical pulling. The filament diameters range from
; about 0.000112" to 0.00075", but this is not critical to
the present invention.
In general, the best properties will be obtained
if the sized filamentous glass reinforcement comprises from
8 CH 2419
7~
about 1 -to about 80% by weight based on the combined weight
of glass and polymers and preferably from about 10 to about
50% by weight. Especially preferably the glass will comprise
from about 10 to about 40% by weight based on the combined
weight of glass and resin. Generally, for direct molding use,
up to about 60% of glass can be present without causing flow
; problems. However, it is useful also to prepare the
compositions containing substantially greater quantities, e.g.,
up to 70-80% by weight of glass. These concentrates can then
be custom blended with resin compostions that are not glass
reinforced to provide any desired glass content of a lower
value.
The length of the glass filaments and whether or
not they are bundled into fibers and the fibers bundled in
turn to yarns, ropes or rovings/ or woven into mats, and the
like, are also not critical to the invention. However, in
preparing the p:resent compositions it is convenient to use
the filamentous glass in the form of chopped strands of from
about 1/8" to about 1" long, preferab]y less than 1/4" long.
In articles molded from the compositions, on the other hand,
even shorter lengths will be encountered because, during
compounding, considerable fragmentation will occur. This is
desirable, however, because the best properties are exhibited
by thermoplastic injection molded articles in which the fila-
ment lengths lie between about 0.000005" and 0.125'l
Because i* has been found that certain commonly
used flammable sizings on the glass, e.g., dextrinized starch
or synthetic polymers, contribute flammability often in
greater proportion than expected from the amount present, it
is preferred to use lightly sized or unsized glass rein-
forcements in those compositions of the present invention
which are flame-.retardant. Sizings, if present, can readily
- 12 -
~ 8 CH 2419
be removed by heat cleaning or other techniques well known
to those skilled in the art.
It is a preferred feature of this invention also to
provide flame-retardant thermoplastic compositions, as defined
above, by modifying the composition to include a flame-
retardant additive in a minor proportion but in an amount at
least sufficient to render the composition non-burning or self-
extinguishing.
A preferred feature of the invention is a flame-
retardant composition as above defined, which also includes a
halogenated organic compound, a halogenated organic compound
in admixture with an antimony compound r elemental phosphorus,
or a phosphorus compound or compounds containing phosphorus-
nitrogen bonds, or a mixture of two or more of the foregoing.
When used herein, the terms "non-burning", "self
extinguishing", and "non-dripping" are used to describe compo-
sitions which meet the standards of ASTM test method D-635
and Underwriters' Laboratories Bulletin No.94. Another
recognized procedure to determine flame resistance of resinous
compositions is the Oxygen Index Test or LOI (Limiting Oxygen
Index). This test is a direct measure of a products combus-
tibility based on the oxygen content of the combustion atmo-
sphere. Appropriate specimens are placed in a combustion
chimney, and the oxygen is reduced stepwise until the material
no longer supports a flame. The IOI is defined as the percent
oxygen times 100 divided by the sum of the percentages of
nitrogen and oxygen in the gas used to burn the material under
test. Further details of the Oxygen Index Test are found in
ASTM test Method D-2863~ The compositions of this invention
which contain flame~retardant additives in the speci~ied
amounts have a substantially higher oxygen index and thus are
much less combustible than the controls.
- 13 -
~ 7,~ 8 CH 2419
The flame-retardant additives useful in this inven-
tion comprise a family of chemica] compounds well known to
those skilled in the axt. Cenerally speaking, the more
important of these compounds contain chemical elements employed
for their ability to impart flame resistance, e.g., bromine,
chlorine, antimony, phosphorus, and nitrogen. It is
preferred tha-t the flame-retardant additive comprise a
halogenated organic compound (brominated or chlorinated); a
halogen-containing organic compound in admixture with antimony
oxide; elemental phosphorus or a phosphorus compound; a
halogen-containing compound in admixture with a phosphorus
compound or compounds containing phosphorus-nitrogen bonds;
or a mixture of two or more of the foregoing.
The amount of flame-retardant additive used is not
critical to the invention, so long as it is present in a minor
proportion based on the thermoplastic composition -- major
proportions will detract from physical properties -- but at
least sufficient to render the composition non-burning or self-
extinguishing. Those skilled in the art are well aware that
the amount will vary with the nature of the polymers in the
composition and with the efficiency of the additive. In gen-
eral, however, the amount of additive will be from about 0.5
to 50 parts be weight per hundred parts of components (i),
(ii), and (iii). A preferred range will be from about 3 to 25
parts and an especially preferred range will be from about
5 to 15 parts of additive per 100 parts of (i), (ii), and (iii).
Smaller amounts of compounds highly concentrated in the ele-
ments responsible for flame-retardance will be sufficient,
e.g., elemental red phosphorus will be preferred at about
0.5 to 10 parts by weight per hundred parts of (i), (ii), and
(iii), while phosphorus in the form of triphenyl phosphate
will be used at about 5 to 25 parts of phosphate per part of
- 14 -
~ 8 C~ 2419
(i~, (ii), and (iii), and so forth. Halogenated aromatics
will be used at about 2 to 20 parts and synergists, e.g.,
antimony oxide, will be used at about 1 to 10 parts by weight
per 100 parts of components (i), (ii), and (iii).
Among the useful halogen containing compounds are
those of the formula
( ~ ~ ~ b ~ ~ c )
wherein n is 1 to 10 and R is an alkylene, alkylidene, or
cycloaliphatic linkage, e.g., methylene, ethylene, propylene,
isopropylene, isopropylidene, butylene, isobutylene, amylene,
cyclohexylene, cyclopentylidene, and the like; or a linkage
selected from the group consisting of ether; carbonyl; amine;
a sulfur-containing linkage, e.g., sulfide, sulfoxide, or
sulfone; carbonate; a phosphorus-containing linkage; and the
like. R can also consist of two or more alkylene or
alkylidene lin]cages connected by such groups as aromatic,
amino, ether, ester, carbonyl, sulfide, sulfoxide, sulfone,
a phosphorus-containing linkage, and the like. R can be
dihydric phenol, e.g., bisphenol-A, carbonate linkage. Other
groups which are represented by R will occur to those skilled
in the art.
Ar and Ar' are ~mono- or polycarbocyclic aromatic
groups such as phenylene, biphenylene, terphenylene,
naphthylene, and the like. Ar and Ar' may be the same or
different.
X is a monovalent hydrocarbon group exemplified by
'
15 -
~ 8 ~H 2419
`
the following: alkyl groups, such as methyl, ethyl, propyl,
isopropyl, butyl, decyl, and the like, aryl groups, such as
phenyl, naphthyl, biphenyl, xylyl, totyl, and the like; aralkyl
groups, such as benzyl, ethylphenyl, and the like; cyclo-
aliphatic groups, such as cyclopentyl, cyclohexyl, and the
li]~e, as well as monovalent hydrocarbon groups containing
inert substituents therein. It will be understood that where
more than one X is used, they may be alike or different.
Y is a substituent selected from the group consisting
of organic, inorganic, and organometallic radicals. The sub-
stituents represented by Y include (1) halogen, eOg., chlorine,
bromine, iodine, or fluorine, (2) ether groups of the general
formula OE, wherein E is a monovalent hydrocarbon radical
~; similar to X, (3) monovalent hydrocarbon groups of the type
represented by R, and (4) other substituents, e.g., nitro,
cyano, etc., said substituents being essentially inert provided
there be at least one and pxeferably two halogen atoms per
aryl, e.g., phenyl, nucleus.
The letter d represents a whole number ranging from
1 to a maximum equivalent to the number of replaceable
hydrogens substituted on the aromatic rings comprising Ar or Ar'.
The letter e represents a whole number ranging from 0 to a
maximum controlled by the number of replaceable hydrogens
on R. The letters a,b, and c represent whole numbers
including 0. When b is not 0, neither a nor c may be 0, and
when b is 0, either a or c, but not both, may be 0. Where b
is 0, the aromatic groups are ~oined by a direct carbon-
carbon bond.
The hydroxyl and Y substituents on the aromatic
groups, Ar and Ar', can be varied in the ortho, meta, or para
positions on the aromatic rings, and -the groups can be in any
possible geometric relationship with respect to one another.
~ 8 ~H 2419
:
Included withln the scope of the above formula are
di-aromatics of which the following axe representative
2,2-bi.s (3,5-dichlorophenyl~propane
bis-(2-chlorophenyl)methane
bis-(2,6-dibromophenyl)methane
l,l-bis-(4-iodophenyl)ethane
1,2-bis-(2,6-dichlorophenyl)ethane
l,l-bis-(2-chloro-4-iodophenyl)ethane
l,l-bis-(2-chloro-4-methylphenyl)ethane
1,1-bis-(3,5-dichlorophenyl)ethane
2,2-bis-(3-phenyl~4-bromophenyl)ethane
2,3-bis-(4,6-dichloronaphthyl)propane
2,2-bis-(2,6-dichlorophenyl)pentane
2,2-bis-(3,5-dichromophenyl)hexane
bis-(4-chlorophenyl)phenylmethane
bis-(3,5-di.chlorophenyl)cyclohexylmethane
bis-(3-nitro-4-bromophenyl)methane
bis-(4-hydroxy-2,6-dichloro-3-methoxyphenyl)methane
2,2-bis-(3,5-dichloro-4-hydroxyphenyl~propane
2,2-bis-(3-bromo-4-hydroxyphenyl)propane
The preparation of these and other applicable bi-
phenyls are known in the art~ In the above examples sulfide,
sulfoxy, and the like may be substituted in place of the di-
valent aliphatic group.
Included within the above structural formula are
substituted benzenes exemplified by tetrabromobenzene,
hexachlorobenzene, hexabromobenzene, and biphenyls such as
2,2'-dichlorobiphenyl, 2,4'-dibromobiphenyl, 2,4'-dichloro-
biphenyl, hexabromobiphenyl, octabromobiphenyl, decabromo-
biphenyl, and halogenated diphenyl ethers containing from
2 to lO halogen atoms.
The preferred halogen compounds for this invention
~ 7~ 8 CH 2419
are aromatic halogen compounds such as chlorinated benzene,
brominated benzene r chlorinated biphenyl, chloxinated
terphenyl, brominated biphenyl, brominated terphenyl, or a
compound comprising two phenyl radicals separated by a divalent
alkylene group and having at least two chlorine or bromine
atoms per phenyl nucleus, or mixtures of at least two of the
foregoing.
Especially preferred are hexabromobenzene and
chlorinated biphenyls or terphenyls, alone, or mixed with
antimony oxideO
Special mention is made of flame-retardant
additives consisting of aromatic carbonate homopolymers
having repeating units of the formula.
(Xl~m Rl (~2)r
~ \\ 11 ~
~ c ~ o c~oJ
R2
wherein R and R are hydrogerL, (:Lower)alkyl or phenyl, Xl
and x2 are bromo or chloro and m and r are from 1 to 4. These
materials may be prepared by techniques well known to those
skilled in the art. Also preferred are aromatic carbonate
copolymers in which from 25 to 75 weight percent of the
repeating units comprise chloro- or bromo-substituted
dihydric phenol, glycol or dicarboxylic acid units. See, e.g.,
A. D. Wambach, U.S. 3,915,926 dated October 28, 1975
above mentioned.
An especially preferred flame-retardant agent will
comprise an aromatic carbonate copolymer of tetrabromobis-
phenol-A and bisphenol-A, preferably in a 50:50 ratio, in
- 18 -
~ CH 2419
combination with an organic or inorganic antimony containing
compound, e.g., antimony oxide, prepared as described in
U.S. 3,915,926 above mentioned.
In general, the preferred phosphate compounds are
selected from the group of elemental phosphorus and organic
phosphonic acids, phosphonates, phosphinates, phosphonites,
phosphinites, phosphene oxides, phosphines, phosphites, and
phosphates. Illustrative is triphenyl phosphene oxide. These
can be used alone or mixed with hexabromobenzene or a chlori-
nated biphenyl and, optionally, antimony oxide.
Typical of the preferred phosphorus compounds to
be employed in this invention would be those having the general
formula
O .
Il .
QO -~ P - OQ
OQ
and nitrogen analogs thereof where each Q represents the same
or different radicals including hydrocarbon radicals such as
alkyl, cycloalkyl, aryl, alkyl substituted aryl, and aryl
substituted alkyl; halogen; hydrogen; and combinations thereof
provided that at least one of said Q's is aryl. Typical
examples of suitable phosphates include, phenylbisdodecyl
phosphate, phenylbisneopentyl phosphate, phenylethylene
hydrogen phosphate, phenylbis~(3,5,5'-trimethylhexyl phosphate),
ethyl-diphenyl phosphate, 2-ethylhexyl di(p-tolyl) phosphate,
diphenyl hydrogen phosphate, bis(2-ethylhexyl? p-tolylphosphate,
tritolyl phosphate, bis-(2-ethylhexyl)-phenyl phosphate, tri
- (nonylphenyl) phosphate, phenylmethyl hydrogen phosphate,
di(dodecyl) p-tolyl phosphate~ tricresyl phosphate, triphenyl
- 19 -
8 CH 2419
~'
phosphate, halogenated triphenyl phosphate, dibutylphenyl
phosphate, 2-chloroethyl-diphenyl phosphate, p-toly:L bis(
2,5,5'-trimethylhexyl) phosphate, 2-ethylhexyldiphenyl
phosphate, diphenyl hydrogen phosphate, and the like. The
preferred phosphates are those where each Q is aryl. The most
preferred phosphate is triphenyl phosphate. It is also pre-
ferred to use triphenyl phosphate in combination with
hexabromobenzene and, optionally, antimony oxide.
Also suitable as flame-retardant additives for this
invention are compounds containing phosphorus-nitrogen bonds,
such as phosphonitrilic chloride, phosphorus ester amides,
phosphoric acid amides, phosphonic acid amides, phosphinic
acid amides, tris(axiridinyl)phosphine oxide, or tetrakis
(hydroxymethyl) phosphonium chloride. These flame-retardant
additives are commercially available.
The compositions of the invention may be formed by
conventional techniques, that is, by first dry mixing the
components to form a premix, and then passing the premix
through an extruder at an elevated temperature, e.g., 425 to
640 F.
By way of illustration, glass roving (a bundle of
strands of filaments) is chopped into small pieces, e.g.,
l/8" to l" in length, and preferably less than l/4" in length
and put into an extrusion compounder with (i) the
polyphenylene ether resin, (ii) the styrene resin, (iii) the
hydroyenated radial teleblock copolymer, and (iv) the flame-
retardant additive (s), to produce molding pellets. The
fibers are shortened and predispersed in the process, coming
out a~ less than l/16" long. In another procedure, glass
filaments are ground or milled to short lengths, are mixed
with the polyphenylene ether resin, the styrene resin, the
radial teleblock copolymer, and optionally, flame-retardant
- 20 ~
~ 8 CH 2419
additive, by dry blending, and then are either fluxed on a
mill and ground, or are extruded and chopped.
In addition~ compounding should be carried out to
insure that the residence time in the machine is short;
that the temperature is carefully controlled; that -the
frictional heat is utilized; and that an intimate mixture
between the resins and the additives is obtained.
The following examples are set forth as further
illustration of the invention and are not to be construed as
limiting the invention thereto.
Comparative Example I. (Sample A)
A premix comprised of 55 parts by weight of poly-
(2,6-dimethyl-1,4-phenylene)ether resin (PPO), and 45 parts
by weight of Foster-Grant's Fostuflex 834 (FG 834), a rubber-
modified polystyrene containing about 8% polybutadiene rubber
was prepared by dry mixing these components with 4 parts tri-
phenyl phosphate, 1.5 parts polyethylene, 1 part tridecyl-
phosphite, 0.15 parts zinc sulfide, and 0~15 parts zinc oxide.
The premix was then compounded on a 28mm twin-screw extruder
at about 500F. The extrudate was cooled and chopped into
pellets~ and the pellets were molded into test bars on a
Newbury injection molding machine.
Example I. (Sample B)
Comparative Example I was repeated with the ex-
ception that the 45 parts of FG 834 were replaced by 30 parts
of Sinclair-Kopper Co.'s Dylene-8G (DYL-8G), "crystal'~ poly-
styrene, and phillips Petroleum's Solprene 502CX ~SOL-502),
which is a radial teleblock copolymer containing hydrogenated
rubber blocks.
Example II.
The composition prepared in the Comparative Example
and Example I were tested, and the results were as follows:
- 21 -
7~
8 CH 2419
Composition ToY~ T.E. Izod GIMP HDT GLOSS MV
Sample A 8900 83 3.0 210 245 53 2100
Sample B 7900 20 6.0 225 259 65 2150
T.Y. - Tensile Yield Strength (psi)
T.E. - Tensile Elongation ~%)
Izod - Notched Izod Impact Strength (ft. lbs./in. notch)
GIMP - Gardner Impact (in. lbs.)
HDT - Heat Deflection Temperature ( F)
&LOSS - 45" Surface Gloss (dimensionless)
MV - Melt Viscosity @ 540F, 1500 sec 1 (poise)
As can be seen above, a thermoplastic composition in
accordance with the invention, Sample B, demonstrated improved
impact resistance and unexpected improvements in surface gloss
over a typical commercial composition, Sample A.
Comparative Example II. (Sample C)
A premix comprised of 50 par-ts by weight of PPO and
50 parts by weight FG 834 was prepared by dry mixing these
components with 3 parts triphenyl phosphate, 1.5 parts poly-
ethylene, 1 part tridecylphosphite, 0.15 parts zinc sulfide,
0.15 parts zinc oxide, and 3 parts titanium dioxide. The pre-
- mix was then compounded on a 28mm twin-screw extruder at about
500F. The extrudate was cooled and chopped into pellets, and
the pe]lets were molded into test bars on a Newbury injection
molding machine.
Comparative Exam~le III. (Sample D)
Comparative Example II was repeated with the
exception that the 50 parts of FG 834 were replaced by 42
parts of DYL-8G and 8 parts of Phillips Petroleum's Solprene
411 (SOL-411), a radial teleblock copolymer comprising
styrene and butadiene.
- 22 -
~ 8 CH 2419
Example III. (Sample E)
,,
The procedure of Comparative Example II was
repeated with the exception that the 50 parts of FG 834
were replaced by 38 parts of DYL-8G and 12 parts o~ SOL-502.
Example IV.
The compositions prepared in Comparative Examples II
and III and Example II were tested to determine the effect of
aging, and the results were as follows:
Izod T.E.
. _
Days @ 115C _ D _ C D
6 4.5 4.0 4.3 94 89 25
11 3.0 3.3 2.5 30 20 16
28 2.2 2.1 2.4 16 7 13
1.0 1.1 1.9 6 6 10
63 1.8 9
91 1.3 8
The results unquestionably show the improved reten-
tion of ductility during heat aging of Sample E, a composition
in accordance with the invention, over Samples C and D, two
known compositions.
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