U.S. patent application number 12/254173 was filed with the patent office on 2009-02-12 for method of making poly(arylene ether) compositions.
This patent application is currently assigned to SABIC INNOVATIVE PLASTICS IP B.V.. Invention is credited to Montgomery M. Alger, Robert Hossan, Torben P. Kempers, Geoffrey H. Riding, David J. Swanson, Michael L. Todt.
Application Number | 20090039320 12/254173 |
Document ID | / |
Family ID | 34968324 |
Filed Date | 2009-02-12 |
United States Patent
Application |
20090039320 |
Kind Code |
A1 |
Alger; Montgomery M. ; et
al. |
February 12, 2009 |
METHOD OF MAKING POLY(ARYLENE ETHER) COMPOSITIONS
Abstract
A method of making a thermoplastic composition comprises melt
mixing a concentrate comprising a first thermoplastic, a second
thermoplastic and an additive with a component selected from the
group consisting of a third thermoplastic, fire retardant additive,
reinforcing agent, electrically conductive filler, non-electrically
conductive filler and combinations of two or more of the
foregoing.
Inventors: |
Alger; Montgomery M.;
(Schnectady, NY) ; Hossan; Robert; (Delmar,
NY) ; Kempers; Torben P.; (Bergen op Zoom, NL)
; Riding; Geoffrey H.; (Castleton, NY) ; Swanson;
David J.; (Stuyvesant Falls, NY) ; Todt; Michael
L.; (Rexford, NY) |
Correspondence
Address: |
CANTOR COLBURN LLP - SABIC (NORYL)
20 Church Street, 22nd Floor
Hartford
CT
06103
US
|
Assignee: |
SABIC INNOVATIVE PLASTICS IP
B.V.
Bergen op Zoom
NL
|
Family ID: |
34968324 |
Appl. No.: |
12/254173 |
Filed: |
October 20, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10815881 |
Mar 31, 2004 |
7439284 |
|
|
12254173 |
|
|
|
|
Current U.S.
Class: |
252/500 ;
524/508; 525/132 |
Current CPC
Class: |
C08L 51/04 20130101;
B29C 48/022 20190201; C08K 5/0008 20130101; B29C 48/40 20190201;
C08J 3/22 20130101; B29C 48/04 20190201; C08L 71/12 20130101; C08J
3/20 20130101; C08K 5/0008 20130101 |
Class at
Publication: |
252/500 ;
524/508; 525/132 |
International
Class: |
C08L 71/12 20060101
C08L071/12; C08F 283/08 20060101 C08F283/08; H01B 1/20 20060101
H01B001/20 |
Claims
1. A thermoplastic composition comprising a blend comprising: a
first thermoplastic, a second thermoplastic and an additive with a
component selected from the group consisting of a third
thermoplastic, fire retardant additive, reinforcing agent,
electrically conductive filler, non-electrically conductive filler,
and combinations of two or more of the foregoing, wherein the first
thermoplastic comprises poly(arylene ether), wherein the second
thermoplastic and third thermoplastic are selected from the group
consisting of poly(alkenyl aromatic) homopolymer resin, rubber
modified poly(alkenyl aromatic) homopolymer resin, polyamide,
polyolefin and combinations of two or more of the foregoing,
wherein the composition comprises less than or equal to about 800
parts per million by weight butyraldehyde based on the total weight
of the poly(arylene ether), less than or equal to about 30 parts
per million by weight trimethylanisole based on the total weight of
the poly(arylene ether), less than or equal to about 100 parts per
million by weight toluene based on the total weight of the
poly(arylene ether), or a combination thereof.
2. The composition of claim 1, wherein the second and third
thermoplastics are the same.
3. The composition of claim 1, wherein the second and third
thermoplastics are different.
4. The composition of claim 1, wherein the second and third
thermoplastics comprise rubber modified polystyrene.
5. The composition of claim 1, wherein the concentrate further
comprises an impact modifier.
6. The composition of claim 5, wherein the impact modifier is
present in an amount of about 1 to about 10 weight percent based on
the total weight of the concentrate.
7. The composition of claim 1, wherein the second thermoplastic
comprises a poly(alkenyl aromatic) resin and the poly(alkenyl
aromatic) resin is present in an amount of about 3 to about 50
weight percent based on the total weight of the concentrate.
8. The composition of claim 1, wherein the second thermoplastic
comprises a polyamide and the polyamide is present in an amount of
about 5 to about 50 weight percent based on the total weight of the
concentrate.
9. The composition of claim 1, wherein the second thermoplastic
comprises a polyolefin and the polyolefin is present in an amount
of about 5 to about 80 weight percent based on the total weight of
the concentrate.
10. The composition of claim 1, wherein the additive is present in
an amount of about 1 to about 25 weight percent based on the total
weight of the concentrate.
11. The composition of claim 1, wherein the concentrate comprises a
combination of additives and the combination of additives is
present in an amount of about 1 to about 25 weight percent based on
the total weight of the concentrate.
12. The composition of claim 1, wherein the composition further
comprises a blowing agent.
13. The composition of claim 1, wherein the additive is selected
from the group consisting of coupling agents, antioxidants, mold
release agents, UV absorbers, light stabilizers, heat stabilizers,
lubricants, plasticizers, pigments, dyes, colorants, anti-static
agents, nucleating agents, anti-drip agents, acid scavengers, and
combinations of two or more of the foregoing.
14. A thermoplastic composition comprising a blend comprising a
poly(arylene ether), a second thermoplastic and an additive with a
component selected from the group consisting of a third
thermoplastic, fire retardant additive, reinforcing agent,
electrically conductive filler, non-electrically conductive filler,
and combinations of two or more of the foregoing, wherein the
second thermoplastic and third thermoplastic are selected from the
group consisting of polystyrene, rubber modified polystyrene and
combinations thereof, and wherein the composition comprises less
than or equal to about 800 parts per million by weight
butyraldehyde, based on the total weight of the poly(arylene
ether), less than or equal to about 30 parts per million by weight
trimethylanisole, based on the total weight of the poly(arylene
ether), and less than or equal to about 100 parts per million by
weight toluene, based on the total weight of the poly(arylene
ether).
15. A method of making a thermoplastic composition comprising melt
mixing a concentrate comprising poly(arylene ether), a second
thermoplastic and an additive with a component selected from the
group consisting of a third thermoplastic, fire retardant additive,
reinforcing agent, electrically conductive filler, non-electrically
conductive filler, and combinations of two or more of the
foregoing, wherein the second thermoplastic and third thermoplastic
are selected from the group consisting of poly(alkenyl aromatic)
homopolymer resin and rubber modified poly(alkenyl aromatic)
homopolymer resin and combinations of two or more of the foregoing,
wherein the concentrate is solid prior to melt mixing, wherein the
concentrate comprises 50 to 99 weight percent poly(arylene ether)
based on the total weight of the concentrate, and wherein the
composition comprises greater than or equal to 34 weight percent
poly(arylene ether), based on the total weight of the
composition.
16. A method of making a thermoplastic composition comprising melt
mixing a concentrate comprising a poly(arylene ether), a second
thermoplastic and an additive with a component selected from the
group consisting of a third thermoplastic, fire retardant additive,
reinforcing agent, electrically conductive filler, non-electrically
conductive filler, and combinations of two or more of the
foregoing, wherein the second thermoplastic and third thermoplastic
are polyamide, wherein the concentrate is solid prior to melt
mixing, wherein the concentrate comprises 50 to 99 weight percent
poly(arylene ether) based on the total weight of the concentrate.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 10/815,881, filed on Mar. 31, 2004, which is
incorporated herein in its entirety.
BACKGROUND OF INVENTION
[0002] This disclosure relates to methods of making poly(arylene
ether) compositions. In particular, the disclosure relates to
methods of making poly(arylene ether) compositions in an
economical, efficient manner.
[0003] Poly(arylene ether) is a thermoplastic material that is
widely used due to a broad range of desirable properties. In some
instances, particularly food related applications, there is a
desire for a more efficient manner of producing poly(arylene ether)
compositions with a low level of volatile, odiferous compounds.
Additionally, there is a general desire to produce poly(arylene
ether) compositions in a more efficient manner. Currently,
poly(arylene ether) compositions are typically produced in a
batchwise manner, with the typical delays associated with a batch
process.
[0004] Accordingly there is a need for a more efficient method of
producing poly(arylene ether) compositions, particularly
poly(arylene ether) compositions having low levels of volatile,
odiferous compounds.
BRIEF DESCRIPTION OF THE INVENTION
[0005] The aforementioned need is met by a method of making a
thermoplastic composition comprising melt-mixing a concentrate
comprising a first thermoplastic, a second thermoplastic and an
additive with a component selected from the group consisting of a
third thermoplastic, fire retardant additive, reinforcing agent,
electrically conductive filler, non-electrically conductive filler,
impact modifier, and combinations of two or more of the
foregoing.
DETAILED DESCRIPTION
[0006] A method of making a thermoplastic composition comprises
continuously melt-mixing a concentrate comprising a first
thermoplastic, a second thermoplastic and an additive with a
component selected from the group consisting of a third
thermoplastic, fire retardant additive, conductive filler,
non-conductive filler, reinforcing agent, impact modifier and
combinations of two or more of the foregoing. The first
thermoplastic is different from the second thermoplastic,
preferably differing in chemical structure not merely molecular
weight. The third thermoplastic may be the same as or different
from the first or second thermoplastic. The concentrate may
optionally comprise an impact modifier. When a third thermoplastic
is present the composition may further comprise a blowing agent.
Use of a concentrate permits the production of thermoplastic
compositions in a more efficient and economical manner with less
waste. In one embodiment the first thermoplastic comprises
poly(arylene ether) and the second thermoplastic and third
thermoplastic are selected from the group consisting of
poly(alkenyl aromatic) resin, polyamide, polyolefin and
combinations of two or more of the foregoing.
[0007] As used herein a concentrate contains an amount of the first
thermoplastic and additive(s) that is higher than is found in the
final composition. The amount of the second thermoplastic may be
higher, lower or the same as that found in the final
composition.
[0008] The terms "first," "second," and the like, herein do not
denote any order or importance, but rather are used to distinguish
one element from another. The terms "a" and "an" herein do not
denote a limitation of quantity, but rather denote the presence of
at least one of the referenced item.
[0009] In one embodiment the concentrate comprises a dry blend of
the first thermoplastic, second thermoplastic and an additive. The
dry blend may be stored until needed, shipped to a second location,
or fed directly to an extruder. The term dry blend, as used herein,
describes a blend produced by mixing the components at a
temperature below the melt temperature of the first and second
thermoplastics. The additive(s) may be in particulate or liquid
form. The dry blend may be continuously added to a melt-mixing
device such as an extruder or kneader. The component melt mixed
with the concentrate (referred to herein as the additional
component) may also be continuously added to the melt in an amount
sufficient to obtain the desired properties in the final
composition. The additional component may be added with the dry
blend concentrate (at the feedthroat of an extruder) or
sequentially (downstream in an extruder). Alternatively, the
additional component may be added initially (at the feedthroat) and
the dry blend concentrate added subsequently (downstream). In one
embodiment the additional component comprises a third
thermoplastic. If the composition comprises more than one
additional component they may be added together or separately.
Changing the amount and/or identity of the additional component
being added can simply and easily vary the makeup of the extruded
composition. Thus differing grades of a material can be produced
without shutting down the production line. During the switch to
producing a different composition the produced material may be fed
back to the melt-mixing device to prevent waste. The amount of
material that is fed back to the melt mixing device depends upon
the design of the device (screw speed and screw design in the case
of an extruder) and can be readily determined by one of ordinary
skill in the art.
[0010] In another embodiment the concentrate comprises a pelletized
blend of the first thermoplastic, second thermoplastic and
additive(s). The concentrate is melt mixed and pelletized. The
pellets may then be stored until needed, shipped to a second
location if necessary, and fed to a melt mixing device or fed
directly to a second melt mixing device such as an extruder or
kneader. The pelletized blend may be fed continuously to the
melt-mixing device. The additional component may also be added
continuously in an amount sufficient to obtain the desired
properties in the final composition. The additional component may
be added simultaneously with the pelletized blend or the pelletized
blend and additional component may be added sequentially. When
added sequentially either the pelletized blend or the additional
component may be added first. In one embodiment the additional
component comprises a third thermoplastic. If the composition
comprises more than one additional component they may be added
together or separately. Changing the amount and/or identity of the
additional component being added can simply and easily vary the
makeup of the final composition. Thus differing grades of a
material can be produced without shutting down the production line.
During the switch to producing a different composition the produced
material may be fed back to the melt-mixing device to prevent
waste. The amount of material that is fed back to the melt mixing
device depends upon the design of the melt mixing device (screw
speed and screw design in the case of an extruder) and can be
readily determined by one of ordinary skill in the art.
[0011] Alternatively, the pelletized concentrate, and additional
component may be dry blended, added to an injection molder and
injection molded or added to the injection molder directly without
prior mixing and injection molded.
[0012] When a pelletized concentrate is employed the resulting
thermoplastic composition has a low odor level, particularly odors
associated with butyraldehyde, trimethylanisole and toluene.
Butyraldehyde can be detected by the human nose at a concentration
as low as 9 billion parts by weight in water. Interestingly,
butyraldehyde concentration typically increases after the first
compounding, particularly when compounded at temperatures greater
than or equal to 300.degree. C. A second compounding step can
decrease the butyraldehyde concentration by about 50% or more. A
decrease in the butyraldehyde concentration is useful particularly
in articles to be used with food and beverages since smells can
have a significant impact on organoleptic properties. In
compositions prepared using the pelletized concentrate the
butyraldehyde level is less than or equal to about 800 parts per
million by weight, based on the total weight of the poly(arylene
ether). Within this range, the butyraldehyde level may be less than
or equal to about 500, or, more specifically, less than or equal to
about 200 parts per million by weight.
[0013] The level of trimethylanisole may be less than or equal to
about 30 parts per million by weight, based on the total weight of
the poly(arylene ether). Within this range, the trimethylanisole
level may be less than or equal to about 5, or, more specifically,
less than or equal to about 1 parts per million by weight.
[0014] The level of toluene may be less than or equal to about 100
parts per million by weight, based on the total weight of the
poly(arylene ether). Within this range, the toluene level may be
less than or equal to about 50, or, more specifically, less than or
equal to about 20 parts per million by weight.
[0015] In another embodiment, the components of the concentrate are
directly and continuously added to a melt mixing device and melt
mixed. The additional component may also be added continuously to
the melt mix in an amount sufficient to obtain the desired
properties in the final composition. The additional component may
be added simultaneously (at the same location as the concentrate
components in an extruder) or sequentially (either upstream or
downstream of the concentrate in an extruder). In one embodiment
the additional component comprises a third thermoplastic. If the
composition comprises more than one additional component the
additional components may be added together or separately. Changing
the amount and/or the identity of the additional component being
added can simply and easily vary the makeup of the extruded
composition. Thus differing grades of a material can be produced
without shutting down the production line. During the switch to
producing a different composition the produced material may be fed
back to the melt-mixing device to prevent waste. The amount of
material that is fed back to the melt mixing device depends upon
the design of the device (screw speed and screw design in an
extruder) and can be readily determined by one of ordinary skill in
the art.
[0016] The term poly(arylene ether) includes polyphenylene ether
(PPE) and poly(arylene ether) copolymers; graft copolymers;
poly(arylene ether) ether ionomers; block copolymers of alkenyl
aromatic compounds, vinyl aromatic compounds, and poly(arylene
ether); and combinations comprising at least one of the foregoing.
Poly(arylene ether)s per se, are known polymers comprising a
plurality of structural units of the formula (I):
##STR00001##
wherein for each structural unit, each Q.sup.1 is independently
hydrogen, halogen, primary or secondary lower alkyl (e.g., alkyl
containing up to 7 carbon atoms), phenyl, haloalkyl, aminoalkyl,
hydrocarbonoxy, halohydrocarbonoxy wherein at least two carbon
atoms separate the halogen and oxygen atoms, or the like; and each
Q.sup.2 is independently hydrogen, halogen, primary or secondary
lower alkyl, phenyl, haloalkyl, hydrocarbonoxy, halohydrocarbonoxy
wherein at least two carbon atoms separate the halogen and oxygen
atoms, or the like. In one embodiment, each Q.sup.1 is alkyl or
phenyl, especially C.sub.1-4 alkyl, and each Q.sup.2 is
hydrogen.
[0017] Both homopolymer and copolymer poly(arylene ether) are
included. Exemplary homopolymers include those containing
2,6-dimethylphenylene ether units. Suitable copolymers include
random copolymers containing, for example, such units in
combination with 2,3,6-trimethyl-1,4-phenylene ether units or
copolymers derived from copolymerization of 2,6-dimethylphenol with
2,3,6-trimethylphenol. Also included are poly(arylene ether)
containing moieties prepared by grafting vinyl monomers or polymers
such as polystyrenes, as well as coupled poly(arylene ether) in
which coupling agents such as low molecular weight polycarbonates,
quinones, heterocycles and formals undergo reaction in known manner
with the hydroxy groups of two poly(arylene ether) chains to
produce a higher molecular weight polymer. Poly(arylene ether)s
further include combinations comprising at least one of the
above.
[0018] The poly(arylene ether) generally has a number average
molecular weight of about 3,000-40,000 atomic mass units (amu) and
a weight average molecular weight of about 20,000-80,000 amu, as
determined by gel permeation chromatography. The poly(arylene
ether) may have an intrinsic viscosity of about 0.10 to about 0.60
deciliters per gram (dl/g), or, more specifically, about 0.29 to
about 0.48 dl/g, as measured in chloroform at 25.degree. C. It is
also possible to utilize a high intrinsic viscosity poly(arylene
ether) and a low intrinsic viscosity poly(arylene ether) in
combination. Determining an exact ratio, when two intrinsic
viscosities are used, will depend somewhat on the exact intrinsic
viscosities of the poly(arylene ether) used and the ultimate
physical properties that are desired.
[0019] Poly(arylene ether) is typically prepared by the oxidative
coupling of at least one monohydroxyaromatic compound such as
2,6-xylenol or 2,3,6-trimethylphenol. Catalyst systems are
generally employed for such coupling; they typically contain at
least one heavy metal compound such as a copper, manganese or
cobalt compound, usually in combination with various other
materials.
[0020] Particularly useful poly(arylene ether) for many purposes
are those which comprise molecules having at least one
aminoalkyl-containing end group. The aminoalkyl radical is
typically located in an ortho position to the hydroxy group.
Products containing such end groups may be obtained by
incorporating an appropriate primary or secondary monoamine such as
di-n-butylamine or dimethylamine as one of the constituents of the
oxidative coupling reaction mixture. Also frequently present are
4-hydroxybiphenyl end groups, typically obtained from reaction
mixtures in which a by-product diphenoquinone is present,
especially in a copper-halide-secondary or tertiary amine system. A
substantial proportion of the polymer molecules, typically
constituting as much as about 90% by weight of the polymer, may
contain at least one aminoalkyl-containing and/or 4-hydroxybiphenyl
end groups.
[0021] Based upon the foregoing, it will be apparent to those
skilled in the art that the contemplated poly(arylene ether) resin
may include many of those poly(arylene ether) resins presently
known, irrespective of variations in structural units or ancillary
chemical features.
[0022] The poly(arylene ether) is present in the concentrate in an
amount of about 50 to about 99 weight percent based on the total
weight of the concentrate. Within this range the poly(arylene
ether) may be present in an amount greater than or equal to about
50, or, more specifically, preferably greater than or equal to
about 60, or, even more specifically, and more preferably greater
than or equal to about 80 weight percent. Also within this range
the poly(arylene ether) may be present in an amount less than or
equal to about 95, or more specifically, less than or equal to
about 90 weight percent.
[0023] The term "poly(alkenyl aromatic) resin" as used herein
includes polymers prepared by methods known in the art including
bulk, suspension, and emulsion polymerization, which contain at
least 25% by weight of structural units derived from an alkenyl
aromatic monomer of the formula
##STR00002##
wherein W.sup.1 is hydrogen, C.sub.1-C.sub.8 alkyl, or halogen;
Z.sup.1 is vinyl, halogen or C.sub.1-C.sub.8 alkyl; and p is 0 to
5. Exemplary alkenyl aromatic monomers include styrene,
chlorostyrene, and vinyltoluene. The poly(alkenyl aromatic) resins
include homopolymers of an alkenyl aromatic monomer; random
copolymers of an alkenyl aromatic monomer, such as styrene, with
one or more different monomers such as acrylonitrile, butadiene,
alpha-methylstyrene, ethylvinylbenzene, divinylbenzene and maleic
anhydride; and rubber-modified poly(alkenyl aromatic) resins
comprising blends and/or grafts of a rubber modifier and a
homopolymer of an alkenyl aromatic monomer (as described above),
wherein the rubber modifier may be a polymerization product of at
least one C.sub.4-C.sub.10 nonaromatic diene monomer, such as
butadiene or isoprene, and wherein the rubber-modified poly(alkenyl
aromatic) resin comprises about 98 to about 70 weight percent of
the homopolymer of an alkenyl aromatic monomer and about 2 to about
30 weight percent of the rubber modifier, or more specifically,
about 88 to about 94 weight percent of the homopolymer of an
alkenyl aromatic monomer and about 6 to about 12 weight percent of
the rubber modifier wherein the weight percents are based on the
total weight of the rubber-modified poly(alkenyl aromatic)
resin.
[0024] The stereoregularity of the poly(alkenyl aromatic) resin may
be atactic or syndiotactic. Highly preferred poly(alkenyl aromatic)
resins include atactic and syndiotactic homopolystyrenes. Suitable
atactic homopolystyrenes are commercially available as, for
example, EB3300 from Chevron, and P1800 from BASF. Suitable
syndiotactic homopolystyrenes are commercially available from Dow
Chemical Company and from Idemitsu Kosan Company, Ltd. Highly
preferred poly(alkenyl aromatic) resins further include the
rubber-modified polystyrenes, also known as high-impact
polystyrenes or HIPS, comprising about 88 to about 94 weight
percent polystyrene and about 6 to about 12 weight percent
polybutadiene. These rubber-modified polystyrenes are commercially
available as, for example, GEH 1897 from General Electric Plastics,
and BA 5350 from Chevron.
[0025] The concentrate may comprise the poly(alkenyl aromatic)
resin in an amount of about 3 to about 50 weight percent based on
the total weight of the concentrate. Within this range the
poly(alkenyl aromatic) resin may be present in an amount greater
than or equal to about 5, or, more specifically, greater than or
equal to about 10, or even more specifically, greater than or equal
to about 15 weight percent. Also within this range the poly(alkenyl
aromatic) resin may be present in an amount less than or equal to
about 50, or, more specifically, less than or equal to about 40,
or, even more specifically less than or equal to about 25 weight
percent.
[0026] Polyamide resins are a generic family of resins known as
nylons, characterized by the presence of an amide group
(--C(O)NH--). Nylon-6 and nylon-6,6 are the generally preferred
polyamides and are available from a variety of commercial sources.
Other polyamides, however, such as nylon-4,6, nylon-12, nylon-6,10,
nylon 6,9, nylon 6/6T and nylon 6,6/6T with triamine contents below
about 0.5 weight percent, as well as others, such as the amorphous
nylons may be useful for particular PPO-polyamide applications.
Mixtures of various polyamides. as well as various polyamide
copolymers, are also useful. The most preferred polyamide is
polyamide-6,6.
[0027] The polyamides can be obtained by a number of well known
processes such as those described in U.S. Pat. Nos. 2,071,250;
2,071,251; 2,130,523; 2,130,948; 2,241,322; 2,312,966; and
2,512,606. Nylon-6, for example, is a polymerization product of
caprolactam. Nylon-6,6 is a condensation product of adipic acid and
1,6-diaminohexane. Likewise, nylon 4,6 is a condensation product
between adipic acid and 1,4-diaminobutane. Besides adipic acid,
other useful diacids for the preparation of nylons include azelaic
acid, sebacic acid, dodecane diacid, as well as terephthalic and
isophthalic acids, and the like. Other useful diamines include
m-xylyene diamine, di-(4-aminophenyl)methane,
di-(4-aminocyclohexyl)methane; 2,2-di-(4-aminophenyl)propane,
2,2-di-(4-aminocyclohexyl)propane, among others. Copolymers of
caprolactam with diacids and diamines are also useful.
[0028] Polyamides having viscosity of up to about 400 ml/g can be
used, or, more specifically, having a viscosity of about 90 to
about 350 ml/g, or, even more specifically, about 110 to about 240
ml/g, as measured in a 0.5 wt % solution in 96 wt % sulphuric acid
in accordance with ISO 307.
[0029] The concentrate may comprise polyamide in an amount of about
5 to about 50 weight percent, based on the total weight of the
concentrate. Within this range polyamide may be present in an
amount greater than or equal to about 7, or, more specifically,
greater than or equal to about 10, or, even more specifically,
greater than or equal to about 15 weight percent. Also within this
range polyamide may be present in an amount less than or equal to
about 45, or more specifically, less than or equal to about 35, or
even more specifically, less than or equal to about 25 weight
percent.
[0030] In compositions comprising poly(arylene ether) and polyamide
a compatibilizing agent may be present, preferably in the
concentrate, to improve the physical properties of the
polyphenylene ether-polyamide resin blend, as well as to enable the
use of a greater proportion of the polyamide component. When used
herein, the expression "compatibilizing agent" refers to those
polyfunctional compounds which interact with the polyphenylene
ether, the polyamide, or, preferably, both. This interaction may be
chemical (e.g. grafting) or physical (e.g. affecting the surface
characteristics of the dispersed phases). In either case the
resulting polyphenylene ether-polyamide composition appears to
exhibit improved compatibility, particularly as evidenced by
enhanced impact strength, mold knit line strength and/or
elongation. As used herein, the expression "compatibilized
polyphenylene ether-polyamide base resin" refers to those
compositions which have been physically or chemically
compatibilized with an agent as discussed above, as well as those
compositions which are physically compatible without such agents,
as taught, for example, in U.S. Pat. No. 3,379,792.
[0031] Suitable compatibilizing agents include, for example, liquid
diene polymers, epoxy compounds, oxidized polyolefin wax, quinones,
organosilane compounds, polyfunctional compounds, and
functionalized polyphenylene ethers obtained by reacting one or
more of the previously mentioned compatibilizing agents with
polyphenylene ether. Use of compatibilizing agent is well known and
readily determinable by one of ordinary skill in the art. In one
embodiment the compatibilizing agent comprise citric acid, maleic
anhydride or a combination thereof.
[0032] Polyolefins have the general structure: C.sub.2H.sub.2n and
include polyethylene, polypropylene and polyisobutylene with
preferred homopolymers being polyethylene, LLDPE (linear low
density polyethylene), HDPE (high density polyethylene) and MDPE
(medium density polyethylene) and isotatic polypropylene.
Polyolefin resins of this general structure and methods for their
preparation are well known in the art and are described for example
in U.S. Pat. Nos. 2,933,480, 3,093,621, 3,211,709, 3,646,168,
3,790,519, 3,884,993, 3,894,999, 4,059,654, 4,166,055 and
4,584,334.
[0033] Copolymers of polyolefins may also be used such as
copolymers of ethylene and alpha olefins like propylene,
4-methylpentene-1 and octene. Copolymers of ethylene and
C.sub.3-C.sub.10 monoolefins and non-conjugated dienes, herein
referred to as EPDM copolymers, are also suitable. Examples of
suitable C.sub.3-C.sub.10 monoolefins for EPDM copolymers include
propylene, 1-butene, 2-butene, 1-pentene, 2-pentene, 1-hexene,
2-hexene and 3-hexene. Suitable dienes include 1,4 hexadiene and
monocylic and polycyclic dienes. Mole ratios of ethylene to other
C.sub.3-C.sub.10 monoolefin monomers can range from 95:5 to 5:95
with diene units being present in the amount of from 0.1 to 10 mol
%. EPDM copolymers can be functionalized with an acyl group or
electrophilic group for grafting onto the polyphenylene ether as
disclosed in U.S. Pat. No. 5,258,455.
[0034] The concentrate may comprise polyolefin in an amount of
about 5 to about 80 weight percent, based on the total weight of
the concentrate. Within this range polyolefin may be present in an
amount greater than or equal to about 5, or, more specifically,
greater than or equal to about 30, or, even more specifically,
greater than or equal to about 50 weight percent. Also within this
range polyolefin may be present in an amount less than or equal to
about 80, or, more specifically, less than or equal to about 70,
or, even more specifically less than or equal to about 60 weight
percent.
[0035] The concentrate comprises one or more additives including,
but not limited to, coupling agents, antioxidants, mold release
agents, UV absorbers, light stabilizers, lubricants, plasticizers,
pigments, fire retardants, dyes, colorants, anti-static agents,
nucleating agents anti-drip agents, acid scavengers, and
combinations of two or more of the foregoing.
[0036] The concentrate may comprise an additive or combination of
additives in an amount of about 1 to about 25 weight percent based
on the total weight of the concentrate. Within this range the
combination of additives may be present in an amount greater than
or equal to about 2, or, more specifically, greater than or equal
to about 5, or even more specifically greater than or equal to
about 10. Also within this range the combination of additives may
be present in an amount less than or equal to about 23, or, more
specifically, less than or equal to about 20 or, even more
specifically, less than or equal to about 15 weight percent.
[0037] The concentrate may optionally contain an impact modifier.
Impact modifiers include olefin-containing copolymers such as
olefin acrylates and olefin diene terpolymers. An example of an
olefin acrylate copolymer impact modifier is ethylene ethylacrylate
copolymer available from Union Carbide as DPD-6169. Other higher
olefin monomers can be employed as copolymers with alkyl acrylates,
for example, propylene and n-butyl acrylate. Olefin diene
terpolymers known in the art and generally fall into the EPDM
(ethylene propylene diene monomer) family of terpolymers. They are
commercially available such as, for example, EPSYN 704 from
Copolymer Rubber Company. In some embodiments one EPDM polymer may
be employed as the polyolefin component and a separate EPDM polymer
employed as an impact modifer.
[0038] Various rubber polymers and copolymers can also be employed
as impact modifiers. Examples of such rubber polymers are
polybutadiene, polyisoprene, and various other polymers or
copolymers having a rubbery dienic monomer, for example random
copolymers of styrene and butadiene (SBR).
[0039] Other suitable thermoplastic impact modifiers are block
copolymers, for example, A-B diblock copolymers and A-B-A triblock
copolymers having of one or two alkenyl aromatic blocks A, which
are typically styrene blocks, and a rubber block, B, which is
typically an isoprene or butadiene block. The butadiene block may
be partially hydrogenated. Mixtures of these diblock and triblock
copolymers are especially useful.
[0040] Suitable A-B and A-B-A copolymers include but are not
limited to polystyrene-polybutadiene,
polystyrene-poly(ethylene-propylene), polystyrene-polyisoprene,
poly(.alpha.-methylstyrene)-polybutadiene,
polystyrene-polybutadiene-polystyrene (SBS),
polystyrene-poly(ethylene-propylene)-polystyrene,
polystyrene-poly(ethylene-butylene)-polystyrene,
polystyrene-polyisoprene-polystyrene and
poly(alpha-methylstyrene)-polybutadiene-poly(alpha-methylstyrene),
as well as the selectively hydrogenated versions thereof, and the
like. Mixtures of the aforementioned block copolymers are also
useful. Styrene-containing polymers can also be used as impact
modifiers.
[0041] Other copolymers containing vinyl aromatic compounds, for
example styrene, para-methyl styrene, or alpha methyl styrene and
vinyl cyanides, for example acrylonitrile or methacyrlonitrile, may
also be useful as impact modifiers. One example is
styrene-acrylonitrile (SAN), comprising 15 to 30 percent by weight
acrylonitrile (AN) with the remainder styrene. The SAN may be
further modified by grafting to a rubbery substrate such as a
1,4-polybutadiene to produce a rubber graft polymer, e.g.,
acrylonitrile-butadiene-styrene (ABS), and
methacrylonitrile-butadiene-styrene (MBS). High rubber content
(greater than about 50 wt. %) resins of this type (e.g., HRG-ABS)
may be especially useful.
[0042] These types of polymers are often available as core-shell
polymers. The core usually consists substantially of an acrylate
rubber or a butadiene rubber, wherein one or more shells have been
grafted on the core. Usually these shells are built up from a
vinylaromatic compound, a vinylcyanide, an alkyl acrylate or
methacrylate, acrylic acid, methacrylic acid, or a combination of
the foregoing. The core and/or the shell(s) often comprise
multi-functional compounds that may act as a cross-linking agent
and/or as a grafting agent. These polymers are usually prepared in
several stages.
[0043] Other known impact modifiers include various elastomeric
materials such as organic silicone rubbers, elastomeric
fluorohydrocarbons, elastomeric polyesters, random block
polysiloxane-polycarbonate copolymers, and the like. Preferred
organopolysiloxane-polycarbonate block copolymers are the
dimethylsiloxane-polycarbonate block copolymers.
[0044] The concentrate may comprise the optional impact modifier in
an amount of about 1 to about 10 weight percent based on the total
weight of the concentrate. Within this range impact modifier may be
present in an amount greater than or equal to about 2, or, more
specifically, greater than or equal to about 3 weight percent. Also
within this range impact modifier may be present in an amount less
than or equal to about 9, or, more specifically, less than or equal
to about 8, or, even more specifically, less than or equal to about
5 weight percent.
[0045] Impact modifier may also be added to the concentrate to form
the composition, either as the third thermoplastic or in addition
to the third thermoplastic. The amounts of impact modifier added to
the concentrate will depend upon the type of impact modifier and
the desired properties of the final composition.
[0046] As mentioned above, reinforcing agent, electrically
conductive filler, non-electrically conductive filler, reinforcing
agent flame retardant, a third thermoplastic or a combination of
the foregoing may be added to the concentrate.
[0047] Reinforcing agents may be defined as particulate materials
that increase strength or improve another mechanical property.
Reinforcing agents include materials such as, for example,
silicates, fibers, glass fibers (including continuous and chopped
fibers), carbon fibers, carbon nanotubes, graphite, mica, clay,
talc, aramid fibers and combinations of two or more of the
foregoing.
[0048] Electrically conductive fillers include, but are not limited
to, metal flake, metal powder and conductive carbon black. Some
materials, such as carbon nanotubes and metal fiber can function as
both a reinforcing agent and a conductive filler.
[0049] Non-electrically conductive fillers include, but are not
limited to, metal oxides such as titanium dioxide, non-conductive
carbon black, calcium carbonate, or talc. Non electrically
conductive fillers are typically used to change the color, density
or other non-mechanical property of the composition.
[0050] Flame retardants include a range of materials including
organic phosphate flame retardants. An organic phosphate flame
retardant is phosphate compound of the formula (I):
##STR00003##
where R is the same or different and is alkyl, cycloalkyl, aryl,
alkyl substituted aryl, halogen substituted aryl, aryl substituted
alkyl, halogen, or a combination of any of the foregoing. In one
embodiment at least one R is aryl.
[0051] Examples include phenyl bisdodecyl phosphate,
phenylbisneopentyl phosphate, phenyl-bis (3,5,5'-tri-methyl-hexyl
phosphate), ethyldiphenyl phosphate,
2-ethyl-hexyldi(p-tolyl)phosphate, bis-(2-ethylhexyl)
p-tolylphosphate, tritolyl phosphate, bis-(2-ethylhexyl) phenyl
phosphate, tri-(nonylphenyl) phosphate, di-(dodecyl) p-tolyl
phosphate, tricresyl phosphate, triphenyl phosphate, dibutylphenyl
phosphate, 2-chloroethyldiphenyl phosphate, p-tolyl
bis(2,5,5'-trimethylhexyl) phosphate, 2-ethylhexyldiphenyl
phosphate, and the like. In another embodiment each R is aryl.
[0052] Alternatively, the organic phosphate can be a di- or
polyfunctional compound or polymer having the formula
##STR00004##
including mixtures thereof, in which R.sup.1, R.sup.3 and R.sup.5
are, independently, hydrocarbon; R.sup.2, R.sup.4, R.sup.6 and
R.sup.7 are, independently, hydrocarbon or hydrocarbonoxy; X.sup.1,
X.sup.2 and X.sup.3 are halogen; m and r are 0 or integers from 1
to 4, and n and p are from 1 to 30.
[0053] Examples include the bis diphenyl phosphates of resorcinol,
hydroquinone and bisphenol-A, respectively, or their polymeric
counterparts.
[0054] Methods for the preparation of the aforementioned di- and
polyfunctional aromatic phosphates are described in British Patent
No. 2,043,083.
[0055] Another development is the use of certain cyclic phosphates,
for example, diphenyl pentaerythritol diphosphate, as a flame
retardant agent for poly(arylene ether) resins, as is described by
Axelrod in U.S. Pat. No. 4,254,775.
[0056] Also suitable as flame-retardant additives are compounds
containing phosphorus-nitrogen bonds, such as phosphonitrilic
chloride, phosphorus ester amides, phosphoric acid amides,
phosphonic acid amides, phosphinic acid amides, tris(aziridinyl)
phosphine oxide, or tetrakis(hydroxymethyl) phosphonium chloride.
These flame-retardant additives are commercially available.
[0057] In one embodiment the phosphate flame retardants include
those based upon resorcinol such as, for example, resorcinol
tetraphenyl diphosphate, those based upon bis-phenols such as, for
example, bis-phenol A tetraphenyl diphosphate and triphenyl
phosphates which may be substituted or unsubstituted. The flame
retardant may also comprise a combination of two or more of the
foregoing.
[0058] In the final composition, the flame retardant, when
employed, is present in at least the minimum amount necessary to
impart a degree of flame retardancy to the composition to pass the
UL-94 protocol at a rating of V-0, V-1, or V-2 depending on the
specific application requirements. The particular amount will vary,
depending on the molecular weight of the organic phosphate, the
amount of the flammable resin present and possibly other normally
flammable ingredients which might also be included in the
composition. The organic phosphate flame retardants are generally
present in compositions in amounts of about 2 to about 35 weight
percent, or, more specifically, about 5 to about 30 weight percent,
ore even more specifically, about 10 to about 25 weight percent
based on the total weight of the composition.
[0059] In some embodiments it is desirable for the final
composition to have a heat deflection temperature (HDT) of about
70.degree. C. to about 130.degree. C. as determined at 1.8 mega
Pascals (MPa) by ASTM D648. The concentrate may have an HDT
significantly higher than the HDT of the final composition.
[0060] The method is further illustrated by the following
non-limiting examples.
EXAMPLES
[0061] The materials employed in the following examples are listed
in Table 1.
TABLE-US-00001 TABLE 1 COMPONENT DESCRIPTION/SUPPLIER PPO
Poly(arylene ether) having an intrinsic viscosity of 0.40 dl/g as
measured in chloroform at 25.degree. C. ZnS Zinc sulfide TSAN
Polytetrafluoroethylene encapsulated in styrene- acrylonitrile
resin at a weight ratio of 1:1. TDP Triisodecyl phosphite MgO
Magnesium oxide PE Polyethylene SBS Styrene-butadiene-styrene block
copolymer HIPS Rubber modified polystyrene RDP Resorcinol
diphosphate BPADP Bisphenol A diphosphate
Example 1
[0062] A concentrate as shown in Table 1 was melt mixed and
pelletized. Amounts shown in Table 2 are in weight percent, based
on the total weight of the concentrate. The concentrate was used in
later examples.
TABLE-US-00002 TABLE 2 COMPONENT AMOUNT PPO 74.7 ZnS 0.15 TSAN 0.19
TDP 0.65 MgO 0.15 PE 2.1 SBS 3.3 HIPS 18.7
Examples 2-4
[0063] The concentrate from Example 1 was melt mixed with
additional rubber modified polystyrene as shown in Table 3. The
amount of rubber modified polystyrene is the amount of additional
rubber modified polystyrene in weight percent based on the total
weight of the composition. The compositions were molded and tested.
The concentrate itself was molded and tested for comparison.
TABLE-US-00003 TABLE 3 2 3 4 HIPS 0 25 50 Tensile yield
strength.sup.1 70 64 55 Tensile elongation.sup.1 21.4 21.0 23.7
Flexural modulus.sup.2 2,540 2,490 2,450 Flexural yield
strength.sup.2 108 98 85 Notched Izod.sup.3 125 167 230 HDT.sup.4
153 136 119 .sup.1Determined according to ASTM D638. Yield strength
is in MPa. Elongation is in percent. .sup.2Determined according to
ASTM D790. Results are in MPa. .sup.3Determined according to ASTM
D256. Results are in joules per meter (J/m). .sup.4Determined
according to ASTM D648 at 1.8 MPa and 0.64 centimeters (cm).
Results are in .degree. C.
[0064] Examples 2-4 show that performance varies in a substantially
linear fashion based on the amount of additional rubber modified
polystyrene.
Examples 5-16
[0065] The concentrate from Example 1 was melt mixed with
additional rubber modified polystyrene and RDP as shown in Table 4.
The added amount of RDP and rubber modified polystyrene are in
weight percent based on the total weight of the composition. The
compositions were molded and tested.
[0066] Flammability results are reported as "probability of first
time pass" or p (FTP). Twenty bars were burned by the UL 94 method
and the average and standard deviation of the flame out times was
used to calculate the probability that in the standard test of five
bars the sample would have received a V-0 rating (p(FTP) V0) or a
V-1 rating (p(FTP)V1). A 90% or greater probability of passing the
first time (i.e., p(FTP) of 0.9 or greater) is considered
acceptable performance. Values significantly lower than 0.9 are
considered unacceptable. p(FTP) is calculated only for samples that
do not fail by dripping. Flammability results were obtained for
bars with thickness of 1.5 mm.
TABLE-US-00004 TABLE 4 5 6 7 8 9 10 11 12 13 14 HIPS 25 18.75 0
12.5 12.5 0 0 25 6.25 25 Concentrate 57.5 69.5 82.5 81.5 70 88.25
94 69 82 63.25 RDP 17.5 11.75 17.5 6 17.5 11.75 6 6 11.75 11.75
p(FTP) V0 0.98 0.326 1.00 0 0.986 0.627 0 0 0 0.397 p(FTP) V1 1.00
.999 1.00 0.815 1.00 1.00 0.877 0.914 0.805 0.998 Specific 1.12
1.11 1.14 1.10 1.13 1.12 1.10 1.10 1.12 1.11 gravity Tensile yield
58 63 68 67 63 70 73 60 68 60 strength.sup.1 Tensile 16.2 19.5 15.7
18.3 18.2 19.4 15.3 24.6 18.2 21.4 elongation.sup.1 Flexural 2550
2590 2570 2560 2470 2490 2540 2570 2490 2540 modulus.sup.2 Flexural
yield 86 96 104 101 94 106 109 92 101 91 strength.sup.2 Notched 103
120 107 145 111 105 111 143 113 136 Izod.sup.3 Heat 82 98 95 123 88
12 130 114 109 95 deflection temperature.sup.4 .sup.1Determined
according to ASTM D638. Yield strength is in MPa. Elongation is in
percent. .sup.2Determined according to ASTM D790. Results are in
MPa. .sup.3Determined according to ASTM D256. Results are in J/m.
.sup.4Determined according to ASTM D648 at 1.8 MPa and 0.64 cm.
Results are in .degree. C.
[0067] As can be seen by Examples 5-14 a range of compositions with
a range of physical properties can be made using a single
concentrate.
Examples 15-24
[0068] The concentrate from Example 1 was melt mixed with
additional rubber modified polystyrene and BPADP as shown in Table
5. The added amount of RDP and rubber modified polystyrene is in
weight percent based on the total weight of the composition. The
compositions were molded and tested. Flame retardance was
determined as in Examples 5-14.
TABLE-US-00005 TABLE 5 15 16 17 18 19 20 21 22 23 24 HIPS 25 18.75
0 12.5 12.5 0 0 25 6.25 25 Concentrate 57.5 69.5 82.5 81.5 70 88.25
94 69 82 63.25 BPADP 17.5 11.75 17.5 6 17.5 11.75 6 6 11.75 11.75
p(FTP) V0 0.692 0.583 1.000 0 0.938 0.104 0 0 0.005 0.016 p(FTP) V1
0.996 1.000 1.000 0.471 1.00 0.986 0.714 0.283 0.970 0.912 Specific
1.11 1.11 1.28 1.09 1.12 1.11 1.10 1.09 1.11 1.11 gravity Tensile
yield 62 66 73 67 69 73 73 61 69 68 strength.sup.1 Tensile 18.18
16.19 12.34 1.76 14.05 13.21 14.82 23.52 12.68 16.44
elongation.sup.1 Flexural 2680 2690 2780 2510 2760 2630 2590 2450
2580 2650 modulus.sup.2 Flexural yield 87 101 113 103 103 110 112
95 107 97 strength.sup.2 Notched 125 132 113 139 114 117 129 163
127 160 Izod.sup.3 Heat 84 101 99 125 94 117 135 119 114 101
deflection temperature.sup.4 .sup.1Determined according to ASTM D
638. Yield strength is in MPa. Elongation is in percent.
.sup.2Determined according to ASTM D 790. Results are in MPa.
.sup.3Determined according to ASTM D256. Results are in J/m.
.sup.4Determined according to ASTM D648 at 1.8 MPa and 0.64 cm.
Results are in .degree. C.
[0069] Similar to Examples 5-14, Examples 15-24 show that a range
of compositions with a range of physical properties can be made
using a single concentrate regardless of the choice of flame
retardant.
Example 25
[0070] A sample of 0.40 IV polyphenylene ether powder with a
butyraldehyde level of 114 parts per million by weight was extruded
on a 53 millimeter (mm) twin screw extruder at a rate of 50
kilograms per hour (kg/hr), a screw speed of 310 rotations per
minute (rpm), and a barrel temperature of 290.degree. C. The
extruder used 2 separate water injection zones each followed by a
vacuum vent. Water was injected at a rate of 1.5 kg/hr into each
zone with a vacuum vent pressure of 950 millibar of vacuum. The
extruded product was pelletized and a portion was re-extruded under
the same conditions. This process was repeated 2 more times. The
level of butyraldehyde and other volatiles in the samples is shown
in Table 6.
TABLE-US-00006 TABLE 6 Butyraldehyde Trimethylanisole Sample in ppm
in ppm Toluene in ppm Powder feed 114 26 187 1.sup.st extrusion
pellets 134 1.1 26 2.sup.nd extrusion pellets 49 0.2 0 3.sup.rd
extrusion pellets 25 0 0 4.sup.th extrusion pellets 14 0 0
[0071] As seen in Table 6, although the level of trimethylanisole
and toluene decreased after the first extrusion with water
injection, the level of butyraldehyde was not reduced until after 2
extrusion steps.
Example 26
[0072] A sample of 0.40 IV polyphenylene ether powder with a
butyraldehyde level of 48 parts per million was extruded on a 30 mm
twin screw extruder at a rate of 13.6 kg/hr, a screw speed of 300
rpm, and a barrel temperature of 315.degree. C. The extruder used a
single vacuum vent operated at 600 millibar of vacuum. The extruded
product was pelletized and a portion was re-extruded under the same
conditions. This process was repeated 2 more times. An additional
powder sample was extruded once under the conditions described
above except that the feed rate was 6.8 kg/hr to double the
residence time in the extruder. The level of butyraldehyde and
other volatiles in the samples is shown in Table 7.
TABLE-US-00007 TABLE 7 Butyraldehyde in Trimethylanisole in Sample
ppm ppm powder feed 48 1.02 1.sup.st extrusion pellets 746 1.48
2.sup.nd extrusion pellets 490 0.88 3.sup.rd extrusion pellets 235
0.44 4.sup.th extrusion pellets 129 0.26 1.sup.st extrusion, double
663 1.2 residence time
[0073] This example again shows that the level of butyraldehyde
rises sharply after a single extrusion but begins to drop after
multiple passes through the extruder. This example also shows that
making the residence time of the first extrusion pass equal to the
residence time of two passes is not as effective as two individual
extrusions.
Examples 27-34
[0074] Samples of a blend of 90 weight percent 0.40 IV
polyphenylene ether and 10 weight percent crystal clear polystyrene
were extruded on a 28 mm twin screw extruder at a screw speed of
300 rpm, a barrel temperature of 310.degree. C., and rates of 3.0,
7.5, and 12.0 kg/hr. The extruder used an atmospheric vent plus a
single vacuum vent operated at 800 millibar of vacuum. The extruded
samples were pelletized and re-extruded with additional crystal
clear polystyrene, SEBS rubber, glass fibers, and other additives
to give a final composition of 34 weight percent polyphenylene
ether, 35.5 weight percent polystyrene, 5.5 weight percent rubber,
10 weight percent glass fibers, and 15 weight percent other
additives. Additional samples with the same formulation were
extruded using polyphenylene ether powder instead of the extruded
pellets. These glass filled samples were extruded on a 28 mm twin
screw extruder at a rate of 15 kg/hr, a screw speed of 300 rpm, and
a barrel temperature of 290.degree. C. The extruder used an
atmospheric vent plus a single vacuum vent operated at 800 millibar
of vacuum. Water was injected into the melt before the vacuum vent
at a rate of 0.225 kg/hr to reduce the level of volatile components
in the mixture.
[0075] The pelletized samples were injection molded into 10
centimeter dics, which were then examined by a panel of trained
odor evaluators who gave each sample a score proportional to the
intensity of the odor; scores can vary between 1 (no odor) and 6
(unbearable). The sample scores are shown in Table 8.
TABLE-US-00008 TABLE 8 Sample Odor Number PPO Source for Sample
Score 27 pre-extruded with 10% polystyrene at 12.0 kg/hr 3.3 28
pre-extruded with 10% polystyrene at 7.5 kg/hr 3.0 29 pre-extruded
with 10% polystyrene at 3.0 kg/hr 3.2 30 pre-extruded with 10%
polystyrene at 3.0 kg/hr 3.3 31 PPO powder 4.6 32 PPO powder 3.8 33
PPO powder 3.8 34 PPO powder 3.8
[0076] All of the samples (27-30) made with the polyphenylene
ether/polystyrene blend that was extruded once before compounding
with additional components exhibited lower odor intensity than
samples made directly from polyphenylene ether powder even though
steam stripping was employed.
[0077] While the invention has been described with reference to a
preferred embodiment, it will be understood by those skilled in the
art that various changes may be made and equivalents may be
substituted for elements thereof without departing from the scope
of the invention. In addition, many modifications may be made to
adapt a particular situation or material to the teachings of the
invention without departing from essential scope thereof Therefore,
it is intended that the invention not be limited to the particular
embodiment disclosed as the best mode contemplated for carrying out
this invention, but that the invention will include all embodiments
falling within the scope of the appended claims.
[0078] All cited patents, patent applications, and other references
are incorporated herein by reference in their entirety.
* * * * *