U.S. patent application number 13/602522 was filed with the patent office on 2013-04-04 for fire-resisting thermoplastic composition for plenum raceways and other conduits.
This patent application is currently assigned to TICONA LLC. The applicant listed for this patent is Kaushik Chakrabarty, Christopher McGrady, David McIlroy, Xinyu Zhao. Invention is credited to Kaushik Chakrabarty, Christopher McGrady, David McIlroy, Xinyu Zhao.
Application Number | 20130081850 13/602522 |
Document ID | / |
Family ID | 46964021 |
Filed Date | 2013-04-04 |
United States Patent
Application |
20130081850 |
Kind Code |
A1 |
McGrady; Christopher ; et
al. |
April 4, 2013 |
Fire-Resisting Thermoplastic Composition for Plenum Raceways and
Other Conduits
Abstract
A conduit that contains an elongate member that defines a hollow
passageway is provided. The conduit may be used to convey
electricity (e.g., jacket of a communication cable, raceway for
protecting a communication cable, etc.), fluids (e.g., pipes), etc.
In one embodiment, for example, the conduit may be a raceway for
use in a plenum of a building structure. Regardless of the type of
conduit, at least a portion of the elongate member is formed from a
thermoplastic composition that contains a polyarylene sulfide and
fire-resisting system. Due in part to the specific nature and
concentration of these components, the present inventors have
discovered that the resulting thermoplastic composition may have a
relatively high melting temperature.
Inventors: |
McGrady; Christopher;
(Florence, KY) ; Chakrabarty; Kaushik; (Florence,
KY) ; McIlroy; David; (Cincinnati, OH) ; Zhao;
Xinyu; (Cincinnati, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
McGrady; Christopher
Chakrabarty; Kaushik
McIlroy; David
Zhao; Xinyu |
Florence
Florence
Cincinnati
Cincinnati |
KY
KY
OH
OH |
US
US
US
US |
|
|
Assignee: |
TICONA LLC
Florence
KY
|
Family ID: |
46964021 |
Appl. No.: |
13/602522 |
Filed: |
September 4, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61541364 |
Sep 30, 2011 |
|
|
|
Current U.S.
Class: |
174/68.3 ;
524/102; 524/126; 524/127; 524/133 |
Current CPC
Class: |
C08K 5/0066 20130101;
Y10T 428/1397 20150115; C08L 81/02 20130101; F16L 9/147 20130101;
F16L 11/125 20130101; Y10T 428/139 20150115; Y10T 428/1393
20150115; C08K 5/0066 20130101; C08K 3/016 20180101 |
Class at
Publication: |
174/68.3 ;
524/133; 524/126; 524/127; 524/102 |
International
Class: |
C08K 5/5313 20060101
C08K005/5313; C08L 81/04 20060101 C08L081/04; H02G 3/04 20060101
H02G003/04; C08K 5/521 20060101 C08K005/521 |
Claims
1. A plenum raceway comprising an elongate member that defines a
hollow passageway for receiving a communication cable, wherein at
least a portion of the elongate member is formed from a
thermoplastic composition that comprises a polyarylene sulfide and
a fire-resisting system, the fire-resisting system comprising at
least one halogen-free, fire-resisting agent, and wherein the
thermoplastic composition has a melting temperature of from about
200.degree. C. to about 500.degree. C.
2. The plenum raceway of claim 1, wherein polyarylene sulfides
constitute from about 30% by weight to about 90% by weight of the
composition, and wherein the fire-resisting system constitutes from
about 1% by weight to about 40% by weight of the composition.
3. The plenum raceway of claim 1, wherein the fire-resisting agent
is an organophosphorous compound.
4. The plenum raceway of claim 3, wherein the organophosphorous
compound is a phosphinate having the general formula (I) and/or
formula (II): ##STR00007## wherein, R.sub.7 and R.sub.8 are,
independently, hydrogen or substituted or unsubstituted, straight
chain, branched, or cyclic hydrocarbon groups having 1 to 6 carbon
atoms; R.sub.9 is a substituted or unsubstituted, straight chain,
branched, or cyclic C.sub.1-C.sub.10 alkylene, arylene,
arylalkylene, or alkylarylene group; Z is a metal or protonated
nitrogen base; m is from 1 to 4; n is from 1 to 4; p is from 1 to
4; and y is from 1 to 4.
5. The plenum raceway of claim 4, wherein the phosphinate is a salt
of dimethylphosphinic acid, ethylmethylphosphinic acid,
diethylphosphinic acid, methyl-n-propylphosphinic acid,
methane-di(methylphosphinic acid), ethane-1,2-di(methylphosphinic
acid), hexane-1,6-di(methylphosphinic acid),
benzene-1,4-di(methylphosphinic acid), methylphenylphosphinic acid,
diphenylphosphinic acid, hypophosphoric acid, or a mixture
thereof.
6. The plenum raceway of claim 3, wherein the organophosphorous
compound is a polyphosphate having the following general formula:
##STR00008## v is from 1 to 1000; and Q is a nitrogen base.
7. The plenum raceway of claim 6, wherein the nitrogen base is a
triazine in which one or more of the carbon atoms in the ring
structure are substituted by an amino group.
8. The plenum raceway of claim 6, wherein the nitrogen base is
melamine.
9. The plenum raceway of claim 1, wherein organophosphorous
compounds constitute from about 1% by weight to about 40% by weight
of the thermoplastic composition.
10. The plenum raceway of claim 1, wherein the fire-resisting
system includes an inorganic compound.
11. The plenum raceway of claim 10, wherein the inorganic compound
includes an inorganic molybdate.
12. The plenum raceway of claim 11, wherein the weight ratio of
organophosphorous compounds to inorganic molybdates is from about
0.1 to about 10.
13. The plenum raceway of claim 11, wherein the inorganic molybdate
is zinc molybdate.
14. The plenum raceway of claim 10, wherein the inorganic compound
includes an inorganic borate.
15. The plenum raceway of claim 1, wherein the fire-resisting
system further comprises a nitrogen-containing synergist.
16. The plenum raceway of claim 1, wherein the fire-resisting
system further comprises a fluoropolymer.
17. The plenum raceway of claim 1, wherein the thermoplastic
composition further comprises an impact modifier, aminosilane
coupling agent, mineral filler, fibrous filler, lubricant, or a
combination thereof.
18. The plenum raceway of claim 1, wherein the thermoplastic
composition comprises calcium carbonate.
19. The plenum raceway of claim 1, wherein the polyarylene sulfide
is polyphenylene sulfide.
20. The plenum raceway of claim 1, wherein the thermoplastic
composition exhibits a Limiting Oxygen Index of about 35 or more,
as determined in accordance with ASTM D2863-10.
21. The plenum raceway of claim 1, wherein the thermoplastic
composition exhibits a peak heat release rate of 200 kW/m.sup.2 or
less, as determined in accordance with ASTM E1354-11b.
22. The plenum raceway of claim 1, wherein the thermoplastic
composition exhibits an average specific extinction area of about
0.800 m.sup.2/g or less, as determined in accordance with ASTM
E1354-11b.
23. The plenum raceway of claim 1, wherein the thermoplastic
composition exhibits a maximum average heat of emission of about
150 kW/m.sup.2 or less, as determined in accordance with ASTM
E1354-11b.
24. The plenum raceway of claim 1, wherein the thermoplastic
composition has a halogen content of about 15,000 ppm or less.
25. The plenum raceway of claim 1, wherein the elongate member is
corrugated.
26. A thermoplastic composition, the thermoplastic composition
comprising a polyarylene sulfide and a fire-resisting system, the
fire-resisting system comprising a halogen-free organophosphorous
flame retardant and an inorganic molybdate or inorganic borate,
wherein polyarylene sulfides constitute from about 30% by weight to
about 90% by weight of the composition, and wherein the
fire-resisting system constitutes from about 1% by weight to about
40% by weight of the composition, and wherein the thermoplastic
composition has a melting temperature of from about 200.degree. C.
to about 500.degree. C.
27. The thermoplastic composition of claim 26, wherein the
organophosphorous flame retardant is a phosphinate having the
general formula (I) and/or formula (II): ##STR00009## wherein,
R.sub.7 and R.sub.8 are, independently, hydrogen or substituted or
unsubstituted, straight chain, branched, or cyclic hydrocarbon
groups having 1 to 6 carbon atoms; R.sub.9 is a substituted or
unsubstituted, straight chain, branched, or cyclic C.sub.1-C.sub.10
alkylene, arylene, arylalkylene, or alkylarylene group; Z is a
metal or protonated nitrogen base; m is from 1 to 4; n is from 1 to
4; p is from 1 to 4; and y is from 1 to 4.
28. The thermoplastic composition of claim 27, wherein the
phosphinate is a salt of dimethylphosphinic acid,
ethylmethylphosphinic acid, diethylphosphinic acid,
methyl-n-propylphosphinic acid, methane-di(methylphosphinic acid),
ethane-1,2-di(methylphosphinic acid),
hexane-1,6-di(methylphosphinic acid),
benzene-1,4-di(methylphosphinic acid), methylphenylphosphinic acid,
diphenylphosphinic acid, hypophosphoric acid, or a mixture
thereof.
29. The thermoplastic composition of claim 28, wherein the
organophosphorous flame retardant is a polyphosphate having the
following general formula: ##STR00010## v is from 1 to 1000; and Q
is a nitrogen base.
30. The thermoplastic composition of claim 26, wherein the nitrogen
base is a triazine in which one or more of the carbon atoms in the
ring structure are substituted by an amino group.
31. The thermoplastic composition of claim 26, wherein the nitrogen
base is melamine.
32. The thermoplastic composition of claim 26, wherein
organophosphorous flame retardants constitute from about 1% by
weight to about 40% by weight of the thermoplastic composition.
33. The thermoplastic composition of claim 26, wherein the weight
ratio of organophosphorous flame retardants to inorganic molybdates
is from about 0.1 to about 10.
34. The thermoplastic composition of claim 26, wherein the
inorganic molybdate is zinc molybdate.
35. The thermoplastic composition of claim 26, wherein the
fire-resisting system further comprises a nitrogen-containing
synergist.
36. The thermoplastic composition of claim 26, wherein the
fire-resisting system further comprises a fluoropolymer.
37. The thermoplastic composition of claim 26, wherein the
thermoplastic composition further comprises an impact modifier,
aminosilane coupling agent, mineral filler, fibrous filler,
lubricant, or a combination thereof.
38. The thermoplastic composition of claim 26, wherein the
polyarylene sulfide is polyphenylene sulfide.
39. The thermoplastic composition of claim 26, wherein the
thermoplastic composition exhibits a Limiting Oxygen Index of about
35 or more, as determined in accordance with ASTM D2863-10.
40. The thermoplastic composition of claim 26, wherein the
thermoplastic composition exhibits a peak heat release rate of 200
kW/m.sup.2 or less, as determined in accordance with ASTM
E1354-11b.
41. The thermoplastic composition of claim 26, wherein the
thermoplastic composition exhibits an average specific extinction
area of about 0.800 m.sup.2/g or less, as determined in accordance
with ASTM E1354-11b.
42. The thermoplastic composition of claim 26, wherein the
thermoplastic composition exhibits a maximum average heat of
emission of about 150 kW/m.sup.2 or less, as determined in
accordance with ASTM E1354-11b.
43. The thermoplastic composition of claim 26, wherein the
thermoplastic composition has a halogen content of about 15,000 ppm
or less.
44. A conduit comprising an elongate member that defines a hollow
passageway, wherein at least a portion of the elongate member is
formed from a thermoplastic composition that comprises a
polyarylene sulfide and a fire-resisting system, the fire-resisting
system comprising at least one halogen-free, fire-resisting agent,
and wherein the thermoplastic composition has a melting temperature
of from about 200.degree. C. to about 500.degree. C. and a halogen
content of about 15,000 ppm or less.
45. The conduit of claim 44, wherein the hollow passageway is
configured to receive a fluid.
46. The conduit of claim 44, wherein the hollow passageway is
configured to receive a cable.
Description
RELATED APPLICATIONS
[0001] The present application claims priority to U.S. Provisional
Application Ser. No. 61/541,364, filed on Sep. 30, 2011, which is
incorporated herein in its entirety by reference thereto.
BACKGROUND OF THE INVENTION
[0002] Buildings are usually designed with a space between a drop
ceiling and a structural floor from which the ceiling is suspended
to serve as a return air plenum for elements of heating and cooling
systems. Alternatively, the building can employ raised floors as a
plenum. Due to the open space provided by the plenum,
communications cables are routinely routed therethrough. While
convenient, this can sometimes introduce safety hazards, both to
the cables and the buildings. For example, when a fire occurs in an
area between a floor and a drop ceiling, it may be contained by
walls and other building elements that enclose that area. However,
if the fire reaches the plenum space, and especially if flammable
material occupies the plenum, it can spread quickly. Also, smoke
can be conveyed through the plenum to adjacent areas and to other
floors.
[0003] For the reasons noted above, the National Electrical Code
(NEC) generally requires the use of conduits (e.g., raceways) to
enclose communication cables within a plenum space. When formed
from a plastic material, the NEC further requires that the conduits
are both flame retardant and possess low smoke generating
properties. In this regard, various materials have been employed in
an attempt to satisfy the NEC requirements for plastic conduits.
One such material is polyvinylidene fluoride ("PVDF").
Unfortunately, PVDF is a fluorocarbon that contains a significant
amount of fluorine, which can result in the emission of toxic and
undesirable gases when heated to high temperatures in a fire.
Alternative polymeric materials have also been employed, such as
polyvinyl chloride ("PVC") and chlorinated polyvinyl chloride
("CPVC"). PVC and CPVC are, however, generally inflexible, which
makes it difficult to readily manipulate the conduit during
installation of the communication cables. Further, due to their
high chlorine content, PVC and CPVC can still emit by-product gases
(e.g., hydrogen chloride) when heated to high temperatures. Various
halogen-free polymers have also been employed, such as high density
polyethylene ("HDPE"). Due to its relatively low melting point,
however, HDPE still does not provide sufficient thermal protection,
particularly if employed near a hot water line within a building.
Furthermore, it is often necessary to employ a bromine-based flame
retardant in HDPE conduits to help improve resistivity to fire.
Once again, the presence of a substantial amount of bromine in the
conduit can still lead to the production of toxins at high
temperatures.
[0004] As such, a need currently exists for a thermoplastic
composition that is generally fire-resisting, has a low halogen
content, and also has a relatively high melting point so that it
can be employed in plenum raceways and other conduits.
SUMMARY OF THE INVENTION
[0005] In accordance with one embodiment of the present invention,
a plenum raceway is disclosed that comprises an elongate member
that defines a hollow passageway for receiving a communication
cable. At least a portion of the elongate member is formed from a
thermoplastic composition that comprises a polyarylene sulfide and
a fire-resisting system. The fire-resisting system comprises at
least one halogen-free, fire-resisting agent, and the thermoplastic
composition has a melting temperature of from about 200.degree. C.
to about 500.degree. C.
[0006] In accordance with another embodiment of the present
invention, a thermoplastic composition for use in an elongate
member of a conduit is disclosed. The thermoplastic composition
comprises a polyarylene sulfide and a fire-resisting system that
comprises a halogen-free organophosphorous flame retardant and an
inorganic molybdate or inorganic borate. Polyarylene sulfides
constitute from about 30% by weight to about 90% by weight of the
composition and the fire-resisting system constitutes from about 1%
by weight to about 40% by weight of the composition. The
thermoplastic composition has a melting temperature of from about
200.degree. C. to about 500.degree. C.
[0007] In accordance with yet another embodiment of the present
invention, a conduit is disclosed that comprises an elongate member
that defines a hollow passageway. At least a portion of the
elongate member is formed from a thermoplastic composition that
comprises a polyarylene sulfide and a fire-resisting system. The
fire-resisting system comprises at least one halogen-free,
fire-resisting agent, and the thermoplastic composition has a
melting temperature of from about 200.degree. C. to about
500.degree. C. and a halogen content of about 15,000 ppm or
less.
[0008] Other features and aspects of the present invention are set
forth in greater detail below.
BRIEF DESCRIPTION OF THE FIGURES
[0009] A full and enabling disclosure of the present invention,
including the best mode thereof to one skilled in the art, is set
forth more particularly in the remainder of the specification,
including reference to the accompanying figures, in which:
[0010] FIG. 1 is a perspective view of one embodiment a conduit
that may be formed in accordance with the present invention;
[0011] FIG. 2 is a perspective view of the communication cable
shown in FIG. 1; and
[0012] FIG. 3 is a cross-sectional view of yet another embodiment
of a conduit that may be formed in accordance with the present
invention.
DETAILED DESCRIPTION
[0013] It is to be understood by one of ordinary skill in the art
that the present discussion is a description of exemplary
embodiments only, and is not intended as limiting the broader
aspects of the present invention.
[0014] Generally speaking, the present invention is directed to a
conduit that contains an elongate member that defines a hollow
passageway. The conduit may be used to convey electricity (e.g.,
jacket of a communication cable, raceway for protecting a
communication cable, etc.), fluids (e.g., pipes), etc. In one
embodiment, for example, the conduit may be a raceway for use in a
plenum of a building structure. Regardless of the type of conduit,
at least a portion of the elongate member is formed from a
thermoplastic composition that contains a polyarylene sulfide and
fire-resisting system. Due in part to the specific nature and
concentration of these components, the present inventors have
discovered that the resulting thermoplastic composition may have a
relatively high melting temperature, such as from about 200.degree.
C. to about 500.degree. C., in some embodiments from about
225.degree. C. to about 400.degree. C., and in some embodiments,
from about 250.degree. C. to about 350.degree. C. The high melting
temperature can allow the conduit to be employed in various high
temperature applications, such as adjacent to hot water lines in a
building.
[0015] Various embodiments of the thermoplastic composition and the
resulting conduit will now be described in more detail.
I. Thermoplastic Composition
[0016] A. Polyarylene Sulfide
[0017] To help achieve the properties noted above, the
thermoplastic composition may comprise at least one polyarylene
sulfide that is able to withstand relatively high temperatures
without melting. Although the actual amount may vary depending on
desired application, polyarylene sulfide(s) typically constitute
from about 30% by weight to about 90% by weight, in some
embodiments from about 40% by weight to about 85% by weight, and in
some embodiments, from about 50% by weight to about 80% by weight
of the thermoplastic composition. The polyarylene sulfide(s)
generally have repeating units of the formula:
--[(Ar.sup.1).sub.n--X].sub.m--[(Ar.sup.2).sub.l--Y].sub.j--[(Ar.sup.3).-
sub.k--Z].sub.l--[(Ar.sup.4).sub.o--W].sub.p--
wherein,
[0018] Ar.sup.1, Ar.sup.2, Ar.sup.3, and Ar.sup.4 are independently
arylene units of 6 to 18 carbon atoms;
[0019] W, X, Y, and Z are independently bivalent linking groups
selected from --SO.sub.2--, --S--, --SO--, --CO--, --O--, --C(O)O--
or alkylene or alkylidene groups of 1 to 6 carbon atoms, wherein at
least one of the linking groups is --S--; and
[0020] n, m, i, j, k, l, o, and p are independently 0, 1, 2, 3, or
4, subject to the proviso that their sum total is not less than
2.
[0021] The arylene units Ar.sup.1, Ar.sup.2, Ar.sup.3, and Ar.sup.4
may be selectively substituted or unsubstituted. Advantageous
arylene units are phenylene, biphenylene, naphthylene, anthracene
and phenanthrene. The polyarylene sulfide typically includes more
than about 30 mol %, more than about 50 mol %, or more than about
70 mol % arylene sulfide (--S--) units. For example, the
polyarylene sulfide may include at least 85 mol % sulfide linkages
attached directly to two aromatic rings. In one particular
embodiment, the polyarylene sulfide is a polyphenylene sulfide,
defined herein as containing the phenylene sulfide structure
--(C.sub.6H.sub.4--S).sub.n-- (wherein n is an integer of 1 or
more) as a component thereof.
[0022] Synthesis techniques that may be used in making a
polyarylene sulfide are generally known in the art. By way of
example, a process for producing a polyarylene sulfide can include
reacting a material that provides a hydrosulfide ion (e.g., an
alkali metal sulfide) with a dihaloaromatic compound in an organic
amide solvent. The alkali metal sulfide can be, for example,
lithium sulfide, sodium sulfide, potassium sulfide, rubidium
sulfide, cesium sulfide or a mixture thereof. When the alkali metal
sulfide is a hydrate or an aqueous mixture, the alkali metal
sulfide can be processed according to a dehydrating operation in
advance of the polymerization reaction. An alkali metal sulfide can
also be generated in situ. In addition, a small amount of an alkali
metal hydroxide can be included in the reaction to remove or react
impurities (e.g., to change such impurities to harmless materials)
such as an alkali metal polysulfide or an alkali metal thiosulfate,
which may be present in a very small amount with the alkali metal
sulfide.
[0023] The dihaloaromatic compound can be, without limitation, an
o-dihalobenzene, m-dihalobenzene, p-dihalobenzene, dihalotoluene,
dihalonaphthalene, methoxy-dihalobenzene, dihalobiphenyl,
dihalobenzoic acid, dihalodiphenyl ether, dihalodiphenyl sulfone,
dihalodiphenyl sulfoxide or dihalodiphenyl ketone. Dihaloaromatic
compounds may be used either singly or in any combination thereof.
Specific exemplary dihaloaromatic compounds can include, without
limitation, p-dichlorobenzene; m-dichlorobenzene;
o-dichlorobenzene; 2,5-dichlorotoluene; 1,4-dibromobenzene;
1,4-dichloronaphthalene; 1-methoxy-2,5-dichlorobenzene;
4,4'-dichlorobiphenyl; 3,5-dichlorobenzoic acid;
4,4'-dichlorodiphenyl ether; 4,4'-dichlorodiphenylsulfone;
4,4'-dichlorodiphenylsulfoxide; and 4,4'-dichlorodiphenyl ketone.
The halogen atom can be fluorine, chlorine, bromine or iodine, and
two halogen atoms in the same dihalo-aromatic compound may be the
same or different from each other. In one embodiment,
o-dichlorobenzene, m-dichlorobenzene, p-dichlorobenzene or a
mixture of two or more compounds thereof is used as the
dihalo-aromatic compound. As is known in the art, it is also
possible to use a monohalo compound (not necessarily an aromatic
compound) in combination with the dihaloaromatic compound in order
to form end groups of the polyarylene sulfide or to regulate the
polymerization reaction and/or the molecular weight of the
polyarylene sulfide.
[0024] The polyarylene sulfide(s) may be homopolymers or
copolymers. For instance, selective combination of dihaloaromatic
compounds can result in a polyarylene sulfide copolymer containing
not less than two different units. For instance, when
p-dichlorobenzene is used in combination with m-dichlorobenzene or
4,4'-dichlorodiphenylsulfone, a polyarylene sulfide copolymer can
be formed containing segments having the structure of formula:
##STR00001##
and segments having the structure of formula:
##STR00002##
or segments having the structure of formula:
##STR00003##
[0025] The polyarylene sulfide(s) may also be linear, semi-linear,
branched or crosslinked. Linear polyarylene sulfides typically
contain 80 mol % or more of the repeating unit --(Ar--S)--. Such
linear polymers may also include a small amount of a branching unit
or a cross-linking unit, but the amount of branching or
cross-linking units is typically less than about 1 mol % of the
total monomer units of the polyarylene sulfide. A linear
polyarylene sulfide polymer may be a random copolymer or a block
copolymer containing the above-mentioned repeating unit.
Semi-linear polyarylene sulfides may likewise have a cross-linking
structure or a branched structure introduced into the polymer a
small amount of one or more monomers having three or more reactive
functional groups. By way of example, monomer components used in
forming a semi-linear polyarylene sulfide can include an amount of
polyhaloaromatic compounds having two or more halogen substituents
per molecule which can be utilized in preparing branched polymers.
Such monomers can be represented by the formula R'X.sub.n, where
each X is selected from chlorine, bromine, and iodine, n is an
integer of 3 to 6, and R' is a polyvalent aromatic radical of
valence n which can have up to about 4 methyl substituents, the
total number of carbon atoms in R' being within the range of 6 to
about 16. Examples of some polyhaloaromatic compounds having more
than two halogens substituted per molecule that can be employed in
forming a semi-linear polyarylene sulfide include
1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene,
1,3-dichloro-5-bromobenzene, 1,2,4-triiodobenzene,
1,2,3,5-tetrabromobenzene, hexachlorobenzene,
1,3,5-trichloro-2,4,6-trimethylbenzene,
2,2',4,4'-tetrachlorobiphenyl, 2,2',5,5'-tetra-iodobiphenyl,
2,2',6,6'-tetrabromo-3,3',5,5'-tetramethylbiphenyl,
1,2,3,4-tetrachloronaphthalene, 1,2,4-tribromo-6-methylnaphthalene,
etc., and mixtures thereof.
[0026] Regardless of the particular structure, the number average
molecular weight of the polyarylene sulfide is typically about
15,000 g/mol or more, and in some embodiments, about 30,000 g/mol
or more. In certain cases, a small amount of chlorine may be
employed during formation of the polyarylene sulfide. Nevertheless,
the polyarylene sulfide may still have a low chlorine content, such
as about 1000 ppm or less, in some embodiments about 900 ppm or
less, in some embodiments from about 1 to about 800 ppm, and in
some embodiments, from about 2 to about 700 ppm. In certain
embodiments, however, the polyarylene sulfide is generally free of
chlorine or other halogens.
[0027] B. Fire-Resistinq System
[0028] In addition to a polyarylene sulfide, the thermoplastic
composition may also comprise a fire-resisting system that is
capable of achieving the desired flammability performance, smoke
suppression, and mechanical properties without the use of
conventional halogen-based flame retardants. Consequently, the
fire-resisting system includes at least one low halogen
fire-resisting agent, such as flame retardants, char-forming
agents, smoke suppressants, etc., as well as mixtures of the
foregoing. The halogen (e.g., bromine, chlorine, and/or fluorine)
content of such an agent is about 500 parts per million by weight
("ppm") or less, in some embodiments about 100 ppm or less, and in
some embodiments, about 50 ppm or less. In certain embodiments, the
fire-resisting agents are free of halogens (i.e., "halogen
free").
[0029] In this regard, the fire-resisting system includes at least
one halogen-free, fire-resisting agent, such as flame retardants,
char-forming agents, smoke suppressants, etc., as well as mixtures
of the foregoing. One example of a suitable flame retardant, for
instance, is an organophosphorous compound, such as a salt of
phosphinic acid and/or diphosphinic acid (i.e., "phosphinate")
having the general formula (I) and/or formula (II):
##STR00004##
[0030] wherein,
[0031] R.sub.7 and R.sub.8 are, independently, hydrogen or
substituted or unsubstituted, straight chain, branched, or cyclic
hydrocarbon groups (e.g., alkyl, alkenyl, alkylnyl, aralkyl, aryl,
alkaryl, etc.) having 1 to 6 carbon atoms, particularly alkyl
groups having 1 to 4 carbon atoms, such as methyl, ethyl, n-propyl,
iso-propyl, n-butyl, or tert-butyl groups;
[0032] R.sub.9 is a substituted or unsubstituted, straight chain,
branched, or cyclic C.sub.1-C.sub.10 alkylene, arylene,
arylalkylene, or alkylarylene group, such as a methylene, ethylene,
n-propylene, iso-propylene, n-butylene, tert-butylene, n-pentylene,
n-octylene, n-dodecylene, phenylene, naphthylene, methylphenylene,
ethylphenylene, tert-butylphenylene, methylnaphthylene,
ethylnaphthylene, t-butylnaphthylene, phenylethylene,
phenylpropylene or phenylbutylene group;
[0033] Z is a metal (e.g., magnesium, calcium, aluminum, antimony,
tin, germanium, titanium, iron, zirconium, cesium, bismuth,
strontium, manganese, lithium, sodium, potassium, etc.) or
protonated nitrogen base;
[0034] m is from 1 to 4, in some embodiments from 1 to 3, and in
some embodiments, from 2 to 3 (e.g., 3);
[0035] n is from 1 to 4, in some embodiments from 1 to 3, and in
some embodiments, from 2 to 3 (e.g., 3);
[0036] p is from 1 to 4, in some embodiments from 1 to 3, and in
some embodiments, from 1 to 2; and
[0037] y is from 1 to 4, in some embodiments from 1 to 3, and in
some embodiments, from 1 to 2.
[0038] The phosphinates may, for instance, be prepared using any
known technique, such as by reacting a phosphinic acid with metal
carbonates, metal hydroxides or metal oxides in aqueous solution.
Suitable phosphinates include, for example, salts (e.g., aluminum
or calcium salt) of dimethylphosphinic acid, ethylmethylphosphinic
acid, diethylphosphinic acid, methyl-n-propylphosphinic acid,
methane-di(methylphosphinic acid), ethane-1,2-di(methylphosphinic
acid), hexane-1,6-di(methylphosphinic acid),
benzene-1,4-di(methylphosphinic acid), methylphenylphosphinic acid,
diphenylphosphinic acid, hypophosphoric acid, etc. The resulting
salts are typically monomeric compounds; however, polymeric
phosphinates may also be formed. Additional examples of suitable
phosphinic compounds and their methods of preparation are described
in U.S. Pat. Nos. 7,087,666 to Hoerold, et al.; 6,716,899 to Klatt,
et al.; 6,270,500 to Kleiner, et al.; 6,194,605 to Kleiner;
6,096,914 to Seitz; and 6,013,707 to Kleiner, et al. One
particularly suitable phosphinate is an aluminum salt of
diethylphosphinic acid, such as commercially available from
Clariant under the name EXOLIT.RTM. (e.g., EXOLIT.RTM. OP 935, OP
930, OP 1230).
[0039] Another suitable halogen-free organophosphorous flame
retardant may be a polyphosphate having the following general
formula:
##STR00005##
[0040] v is from 1 to 1000, in some embodiments from 2 to 500, in
some embodiments from 3 to 100, and in some embodiments, from 5 to
50; and
[0041] Q is a nitrogen base. Suitable nitrogen bases may include
those having a substituted or unsubstituted ring structure, along
with at least one nitrogen heteroatom in the ring structure (e.g.,
heterocyclic or heteroaryl group) and/or at least one
nitrogen-containing functional group (e.g., amino, acylamino, etc.)
substituted at a carbon atom and/or a heteroatom of the ring
structure. Examples of such heterocyclic groups may include, for
instance, pyrrolidine, imidazoline, pyrazolidine, oxazolidine,
isoxazolidine, thiazolidine, isothiazolidine, piperidine,
piperazine, thiomorpholine, etc. Likewise, examples of heteroaryl
groups may include, for instance, pyrrole, imidazole, pyrazole,
oxazole, isoxazole, thiazole, isothiazole, triazole, furazan,
oxadiazole, tetrazole, pyridine, diazine, oxazine, triazine,
tetrazine, and so forth. If desired, the ring structure of the base
may also be substituted with one or more functional groups, such as
acyl, acyloxy, acylamino, alkoxy, alkenyl, alkyl, amino, aryl,
aryloxy, carboxyl, carboxyl ester, cycloalkyl, hydroxyl, halo,
haloalkyl, heteroaryl, heterocyclyl, etc. Substitution may occur at
a heteroatom and/or a carbon atom of the ring structure. For
instance, one suitable nitrogen base may be a triazine in which one
or more of the carbon atoms in the ring structure are substituted
by an amino group. One particularly suitable base is melamine,
which contains three carbon atoms in the ring structure substituted
with an amino functional group. Such bases may form a melamine
polyphosphate, such as those commercially available from BASF under
the name MELAPUR.RTM. (e.g., MELAPUR.RTM. 200 or 200/70).
[0042] In certain embodiments of the present invention, the
fire-resisting system may be formed entirely of one or more
organophosphorous compounds, such as those described above. In
certain embodiments, however, it may be desired to employ
additional compounds to help increase the effectiveness of the
system. Yet, even in such embodiments, organophosphorous compounds
typically constitute about 40% by weight or more, in some
embodiments from about 50% by weight to about 90% by weight, and in
some embodiments, from about 55% by weight to 85% by weight of the
fire-resisting system. Further, in such embodiments,
organophosphorous compounds may likewise constitute from about 1%
by weight to about 40% by weight, in some embodiments from about 2%
by weight to about 30% by weight, and in some embodiments, from
about 5% by weight to about 25% by weight of the thermoplastic
composition.
[0043] In some embodiments of the present invention, inorganic
compounds may be employed as low halogen char-forming agents and/or
smoke suppressants in combination with an organophosphorous
compound. Suitable inorganic compounds (anhydrous or hydrates) may
include, for instance, inorganic molybdates, such as zinc molybdate
(e.g., commercially available under the designation Kemgard.RTM.
from Huber Engineered Materials), calcium molybdate, ammonium
octamolybdate, zinc molybdate-magnesium silicate, etc. Other
suitable inorganic compounds may include inorganic borates, such as
zinc borate (commercially available under the designation
Firebrake.RTM. from Rio Tinto Minerals), etc.); zinc phosphate,
zinc hydrogen phosphate, zinc pyrophosphate, basic zinc chromate
(VI) (zinc yellow), zinc chromite, zinc permanganate, silica,
magnesium silicate, calcium silicate, calcium carbonate, titanium
dioxide, magnesium dihydroxide, and so forth. When employed, the
weight ratio of the organophosphorous compound(s) to inorganic
compounds (e.g., inorganic molybdates) may be selectively
controlled to achieve a suitable balance between flame retardancy
and mechanical properties. For example, the ratio may be within the
range of from about 0.1 to about 10, in some embodiments from about
0.5 to about 6, and in some embodiments, from about 1 to about 4.
Inorganic compounds (e.g., inorganic molybdates) may, for example,
constitute about 60% by weight or less, in some embodiments from
about 10% by weight to about 50% by weight, and in some
embodiments, from 15% by weight to about 45% by weight of the
fire-resisting system. The inorganic compounds (e.g., inorganic
molybdates) may also constitute from about 0.5% by weight to about
25% by weight, in some embodiments from about 1% by weight to about
20% by weight, and in some embodiments, from about 3% by weight to
about 15% by weight of the thermoplastic composition.
[0044] If desired, other additives may also be employed in the
fire-resisting system of the present invention. For instance,
nitrogen-containing synergists may be employed that act in
conjunction with the organophosphorous compound(s) to result in a
more effective fire-resisting system. Such nitrogen-containing
synergists may include those of the formulae (III) to (VIII), or a
mixture of thereof:
##STR00006##
[0045] wherein,
[0046] R.sub.5, R.sub.6, R.sub.7, R.sub.9, R.sub.10, R.sub.11,
R.sub.12, and R.sub.13 are, independently, hydrogen;
C.sub.1-C.sub.8 alkyl; C.sub.5-C.sub.16-cycloalkyl or
alkylcycloalkyl, optionally substituted with a hydroxy or a
C.sub.1-C.sub.4 hydroxyalkyl; C.sub.2-C.sub.8 alkenyl;
C.sub.1-C.sub.8 alkoxy, acyl, or acyloxy; C.sub.6-C.sub.12-aryl or
arylalkyl; OR.sup.8 or N(R.sup.8)R.sup.9, wherein R.sup.8 is
hydrogen, C.sub.1-C.sub.8 alkyl, C.sub.5-C.sub.16 cycloalkyl or
alkylcycloalkyl, optionally substituted with a hydroxy or a
C.sub.1-C.sub.4 hydroxyalkyl, C.sub.2-C.sub.8 alkenyl,
C.sub.1-C.sub.8 alkoxy, acyl, or acyloxy, or C.sub.6-C.sub.12 aryl
or arylalkyl;
[0047] m is from 1 to 4;
[0048] n is from 1 to 4;
[0049] X is an acid that can form adducts with triazine compounds
of the formula III. For example, the nitrogen-containing synergist
may include benzoguanamine, tris(hydroxyethyl) isocyanurate,
allantoin, glycoluril, melamine, melamine cyanurate, dicyandiamide,
guanidine, etc. Examples of such synergists are described in U.S.
Pat. Nos. 6,365,071 to Jenewein, et al.; 7,255,814 to Hoerold, et
al.; and 7,259,200 to Bauer, et al. One particularly suitable
synergist is melamine cyanurate, such as commercially available
from BASF under the name MELAPUR.RTM. MC (e.g., MELAPUR.RTM. MC 15,
MC25, MC50).
[0050] The weight ratio of the organophosphorous compound(s) to the
optional nitrogen-containing synergist(s) may be within a range of
from about 0.1 to about 10, in some embodiments from about 0.5 to
about 6, and in some embodiments, from about 1 to about 4.
Nitrogen-containing synergists may, for example, constitute about
50% by weight or less, in some embodiments about 40% by weight or
less, and in some embodiments, from 0% by weight to about 20% by
weight of the fire-resisting system. The optional synergists may
likewise constitute from about 0.5% by weight to about 20% by
weight, in some embodiments from about 1% by weight to about 15% by
weight, and in some embodiments, from about 1% by weight to about
10% by weight of the thermoplastic composition.
[0051] Although not necessarily required, the fire-resisting system
and/or the composition itself may also have a relatively low
content of halogens (i.e., bromine, fluorine, and/or chlorine),
such as about 15,000 parts per million ("ppm") or less, in some
embodiments about 5,000 ppm or less, in some embodiments about
1,000 ppm or less, in some embodiments from about 1 ppm to about
800 ppm, and in some embodiments, from about 2 ppm to about 600
ppm. Nevertheless, in certain embodiments of the present invention,
halogen-based fire-resisting agents may still be employed.
Particularly suitable halogen-based fire-resisting agents are
fluoropolymers, such as polytetrafluoroethylene (PTFE), fluorinated
ethylene polypropylene (FEP) copolymers, perfluoroalkoxy (PFA)
resins, polychlorotrifluoroethylene (PCTFE) copolymers,
ethylene-chlorotrifluoroethylene (ECTFE) copolymers,
ethylene-tetrafluoroethylene (ETFE) copolymers, polyvinylidene
fluoride (PVDF), polyvinylfluoride (PVF), and copolymers and blends
and other combination thereof. When employed, such halogen-based
fire-resisting agents typically constitute only about 40 wt. % or
less, in some embodiments about 30 wt. % or less, and in some
embodiments, from about 1 to about 30 wt. % of the fire-resisting
composition. Likewise, the halogen-based fire-resisting agents
typically constitute about 20 wt. % or less, in some embodiments
about 15 wt. % or less, and in some embodiments, from about 1 wt. %
to about 10 wt. % of the thermoplastic composition.
[0052] Regardless of the particular components employed, the
fire-resisting system typically constitutes from about 1% by weight
to about 40% by weight, in some embodiments from about 2% by weight
to about 30% by weight, and in some embodiments, from about 4% by
weight to about 25% by weight of the thermoplastic composition.
[0053] C. Other Additives
[0054] In addition to the polyarylene sulfide and fire-resisting
system, the thermoplastic composition may also contain a variety of
other additives to enhance its processability and/or properties. In
one embodiment, for example, at least one impact modifier may be
employed in the composition to help improve its mechanical
properties. Examples of suitable impact modifiers may include, for
instance, polyepoxides, polyurethanes, polybutadiene,
acrylonitrile-butadiene-styrene, polysiloxanes etc., as well as
mixtures thereof. In one particular embodiment, a polyepoxide
modifier is employed that contains at least two oxirane rings per
molecule. The polyepoxide may be a linear or branched, homopolymer
or copolymer (e.g., random, graft, block, etc.) containing terminal
epoxy groups, skeletal oxirane units, and/or pendent epoxy groups.
The monomers employed to form such polyepoxides may vary. In one
particular embodiment, for example, the polyepoxide modifier
contains at least one epoxy-functional (meth)acrylic monomeric
component. The term "(meth)acrylic" includes acrylic and
methacrylic monomers, as well as salts or esters thereof, such as
acrylate and methacrylate monomers. Suitable epoxy-functional
(meth)acrylic monomers may include, but are not limited to, those
containing 1,2-epoxy groups, such as glycidyl acrylate and glycidyl
methacrylate. Other suitable epoxy-functional monomers include
allyl glycidyl ether, glycidyl ethacrylate, and glycidyl
itoconate.
[0055] If desired, additional monomers may also be employed in the
polyepoxide to help achieve the desired melt viscosity. Such
monomers may vary and include, for example, ester monomers,
(meth)acrylic monomers, olefin monomers, amide monomers, etc. In
one particular embodiment, for example, the polyepoxide modifier
includes at least one linear or branched .alpha.-olefin monomer,
such as those having from 2 to 20 carbon atoms and preferably from
2 to 8 carbon atoms. Specific examples include ethylene, propylene,
1-butene; 3-methyl-1-butene; 3,3-dimethyl-1-butene; 1-pentene;
1-pentene with one or more methyl, ethyl or propyl substituents;
1-hexene with one or more methyl, ethyl or propyl substituents;
1-heptene with one or more methyl, ethyl or propyl substituents;
1-octene with one or more methyl, ethyl or propyl substituents;
1-nonene with one or more methyl, ethyl or propyl substituents;
ethyl, methyl or dimethyl-substituted 1-decene; 1-dodecene; and
styrene. Particularly desired .alpha.-olefin comonomers are
ethylene and propylene. In one particularly desirable embodiment of
the present invention, the polyepoxide modifier is a copolymer
formed from an epoxy-functional (meth)acrylic monomeric component
and .alpha.-olefin monomeric component. For example, the
polyepoxide modifier may be poly(ethylene-co-glycidyl
methacrylate). One specific example of a suitable polyepoxide
modifier that may be used in the present invention is commercially
available from Arkema under the name Lotader.RTM. AX8840.
Lotader.RTM. AX8840 has a melt flow rate of 5 g/10 min and has a
glycidyl methacrylate monomer content of 8% by weight.
[0056] Still another suitable additive that may be employed to
improve the mechanical properties of the thermoplastic composition
is an organosilane coupling agent. The coupling agent may, for
example, be any alkoxysilane coupling agent as is known in the art,
such as vinlyalkoxysilanes, epoxyalkoxysilanes, aminoalkoxysilanes,
mercaptoalkoxysilanes, and combinations thereof. Aminoalkoxysilane
compounds typically have the formula: R.sup.5--Si--(R.sup.6).sub.3,
wherein R.sup.5 is selected from the group consisting of an amino
group such as NH.sub.2; an aminoalkyl of from about 1 to about 10
carbon atoms, or from about 2 to about 5 carbon atoms, such as
aminomethyl, aminoethyl, aminopropyl, aminobutyl, and so forth; an
alkene of from about 2 to about 10 carbon atoms, or from about 2 to
about 5 carbon atoms, such as ethylene, propylene, butylene, and so
forth; and an alkyne of from about 2 to about 10 carbon atoms, or
from about 2 to about 5 carbon atoms, such as ethyne, propyne,
butyne and so forth; and wherein R.sup.6 is an alkoxy group of from
about 1 to about 10 atoms, or from about 2 to about 5 carbon atoms,
such as methoxy, ethoxy, propoxy, and so forth. In one embodiment,
R.sup.5 is selected from the group consisting of aminomethyl,
aminoethyl, aminopropyl, ethylene, ethyne, propylene and propyne,
and R.sup.6 is selected from the group consisting of methoxy
groups, ethoxy groups, and propoxy groups. In another embodiment,
R.sup.5 is selected from the group consisting of an alkene of from
about 2 to about 10 carbon atoms such as ethylene, propylene,
butylene, and so forth, and an alkyne of from about 2 to about 10
carbon atoms such as ethyne, propyne, butyne and so forth, and
R.sup.6 is an alkoxy group of from about 1 to about 10 atoms, such
as methoxy group, ethoxy group, propoxy group, and so forth. A
combination of various aminosilanes may also be included in the
mixture.
[0057] Some representative examples of aminosilane coupling agents
that may be included in the mixture include aminopropyl
triethoxysilane, aminoethyl triethoxysilane, aminopropyl
trimethoxysilane, aminoethyl trimethoxysilane, ethylene
trimethoxysilane, ethylene triethoxysilane, ethyne
trimethoxysilane, ethyne triethoxysilane,
aminoethylaminopropyltrimethoxysilane, 3-aminopropyl
triethoxysilane, 3-aminopropyl trimethoxysilane, 3-aminopropyl
methyl dimethoxysilane or 3-aminopropyl methyl diethoxysilane,
N-(2-aminoethyl)-3-aminopropyl trimethoxysilane,
N-methyl-3-aminopropyl trimethoxysilane, N-phenyl-3-aminopropyl
trimethoxysilane, bis(3-aminopropyl)tetramethoxysilane,
bis(3-aminopropyl)tetraethoxy disiloxane, and combinations thereof.
The amino silane may also be an aminoalkoxysilane, such as
.gamma.-aminopropyltrimethoxysilane,
.gamma.-aminopropyltriethoxysilane,
.gamma.-aminopropylmethyldimethoxysilane,
.gamma.-aminopropylmethyldiethoxysilane,
N-(.beta.-aminoethyl)-.gamma.-aminopropyltrimethoxysilane,
N-phenyl-.gamma.-aminopropyltrimethoxysilane,
.gamma.-diallylaminopropyltrimethoxysilane and
.gamma.-diallylaminopropyltrimethoxysilane. One suitable amino
silane is 3-aminopropyltriethoxysilane which is available from
Degussa, Sigma Chemical Company, and Aldrich Chemical Company.
[0058] Fillers may also be employed in the thermoplastic
composition to help achieve the desired physical properties and/or
color. When employed, such mineral fillers typically constitute
from about 5% by weight to about 40% by weight, in some embodiments
from about 10% by weight to about 35% by weight, and in some
embodiments, from about 10% by weight to about 30% by weight of the
thermoplastic composition. Clay minerals may be particularly
suitable for use in the present invention. Examples of such clay
minerals include, for instance, talc
(Mg.sub.3Si.sub.4O.sub.10(OH).sub.2), halloysite
(Al.sub.2Si.sub.2O.sub.5(OH).sub.4), kaolinite
(Al.sub.2Si.sub.2O.sub.5(OH).sub.4), illite
((K,H.sub.3O)(Al,Mg,Fe).sub.2(Si,Al).sub.4O.sub.10[(OH).sub.2,(H.sub.2O)]-
), montmorillonite
(Na,Ca).sub.0.33(Al,Mg).sub.2Si.sub.4O.sub.10(OH).sub.2nH.sub.2O),
vermiculite
((MgFe,Al).sub.3(Al,Si).sub.4O.sub.10(OH).sub.24H.sub.2O),
palygorskite ((Mg,Al).sub.2Si.sub.4O.sub.10(OH)4(H.sub.2O)),
pyrophyllite (Al.sub.2Si.sub.4O.sub.10(OH).sub.2), etc., as well as
combinations thereof. In lieu of, or in addition to, clay minerals,
still other mineral fillers may also be employed. For example,
other suitable mineral fillers may also be employed, such as
calcium silicate, aluminum silicate, mica, titanium dioxide,
diatomaceous earth, wollastonite, calcium carbonate, and so forth.
Mica, for instance, may be a particularly suitable mineral for use
in the present invention. There are several chemically distinct
mica species with considerable variance in geologic occurrence, but
all have essentially the same crystal structure. As used herein,
the term "mica" is meant to generically include any of these
species, such as muscovite
(KAl.sub.2(AlSi.sub.3)O.sub.10(OH).sub.2), biotite
(K(Mg,Fe).sub.3(AlSi.sub.3)O.sub.10(OH).sub.2), phlogopite
(KMg.sub.3(AlSi.sub.3)O.sub.10(OH).sub.2), lepidolite
(K(Li,Al).sub.2-3(AlSi.sub.3)O.sub.10(OH).sub.2), glauconite
(K,Na)(Al,Mg,Fe).sub.2(Si,Al).sub.4O.sub.10(OH).sub.2), etc., as
well as combinations thereof.
[0059] Fibrous fillers may also be employed in the thermoplastic
composition. When employed, such fibrous fillers typically
constitute from about 5% by weight to about 40% by weight, in some
embodiments from about 10% by weight to about 35% by weight, and in
some embodiments, from about 10% by weight to about 30% by weight
of the thermoplastic composition. The fibrous fillers may include
one or more fiber types including, without limitation, polymer
fibers, glass fibers, carbon fibers, metal fibers, and so forth, or
a combination of fiber types. In one embodiment, the fibers may be
chopped glass fibers or glass fiber rovings (tows). Fiber diameters
can vary depending upon the particular fiber used and are available
in either chopped or continuous form. The fibers, for instance, can
have a diameter of less than about 100 .mu.m, such as less than
about 50 .mu.m. For instance, the fibers can be chopped or
continuous fibers and can have a fiber diameter of from about 5
.mu.m to about 50 .mu.m, such as from about 5 .mu.m to about 15
.mu.m.
[0060] Lubricants may also be employed in the thermoplastic
composition that are capable of withstanding the processing
conditions of poly(arylene sulfide) (typically from about
290.degree. C. to about 320.degree. 0) without substantial
decomposition. Exemplary of such lubricants include fatty acids
esters, the salts thereof, esters, fatty acid amides, organic
phosphate esters, and hydrocarbon waxes of the type commonly used
as lubricants in the processing of engineering plastic materials,
including mixtures thereof. Suitable fatty acids typically have a
backbone carbon chain of from about 12 to about 60 carbon atoms,
such as myristic acid, palmitic acid, stearic acid, arachic acid,
montanic acid, octadecinic acid, parinric acid, and so forth.
Suitable esters include fatty acid esters, fatty alcohol esters,
wax esters, glycerol esters, glycol esters and complex esters.
Fatty acid amides include fatty primary amides, fatty secondary
amides, methylene and ethylene bisamides and alkanolamides such as,
for example, palmitic acid amide, stearic acid amide, oleic acid
amide, N,N'-ethylenebisstearamide and so forth. Also suitable are
the metal salts of fatty acids such as calcium stearate, zinc
stearate, magnesium stearate, and so forth; hydrocarbon waxes,
including paraffin waxes, polyolefin and oxidized polyolefin waxes,
and microcrystalline waxes. Particularly suitable lubricants are
acids, salts, or amides of stearic acid, such as pentaerythritol
tetrastearate, calcium stearate, or N,N'-ethylenebisstearamide.
When employed, the lubricant(s) typically constitute from about
0.05% by weight to about 1.5% by weight, and in some embodiments,
from about 0.1% by weight to about 0.5% by weight of the
thermoplastic composition.
[0061] Still other additives that can be included in the
composition may include, for instance, antimicrobials, pigments,
antioxidants, stabilizers, surfactants, waxes, flow promoters,
solid solvents, and other materials added to enhance properties and
processability.
[0062] The materials used to form the thermoplastic composition may
be combined together using any of a variety of different techniques
as is known in the art. In one particular embodiment, for example,
the polyarylene sulfide, fire-resisting system, and other optional
additives are melt processed as a mixture within an extruder to
form the thermoplastic composition. The mixture may be melt-kneaded
in a single-screw or multi-screw extruder at a temperature of from
about 250.degree. C. to about 320.degree. C. In one embodiment, the
mixture may be melt processed in an extruder that includes multiple
temperature zones. By way of example, the mixture may be melt
processed using a twin screw extruder such as a Leistritz 18-mm
co-rotating fully intermeshing twin screw extruder. A general
purpose screw design can be used to melt process the mixture. In
one embodiment, the mixture including all of the components (e.g.,
polyarylene sulfide, fire-resisting system, and other optional
additives) may be fed to the feed throat in the first barrel by
means of a volumetric feeder. In another embodiment, different
components may be added at different addition points in the
extruder, as is known. For example, the polyarylene sulfide and
other optional additives may be applied at the feed throat, and the
fire-resisting system may be supplied at a temperature zone located
downstream therefrom. Likewise, when the fire-resisting system
contains different components, those components may also be
supplied at the same or different location along the extruder.
Regardless, the resulting mixture can be melted and mixed then
extruded through a die. The extruded thermoplastic composition can
then be quenched in a water bath to solidify and granulated in a
pelletizer followed by drying. The melt viscosity of the extruded
composition may be about 8 kilopoise or less, in some embodiments
from about 0.5 to about 6 kilopoise, and in some embodiments, from
about 3 to about 5 kilopoise, as determined in accordance with ISO
Test No. 11443 at a shear rate of about 1200 s.sup.-1 and at a
temperature of 316.degree. C.
[0063] As a result of the present invention, a thermoplastic
composition may be formed that has a relatively high melting point
and a relatively low melting point, as discussed above.
Furthermore, the composition is generally flame retardant, which
may be quantified in a variety of different ways. For example, the
degree to which the composition can extinguish a fire ("char
formation") may be represented by its Limiting Oxygen Index
("LOI"), which is the volume percentage of oxygen needed to support
combustion. More particularly, the LOI of the thermoplastic
composition may be about 35 or more, in some embodiments about 40
or more, and in some embodiments, from about 50 to 100, as
determined in accordance with ASTM D2863-10. Another parameter that
represents the flammability of a composition is the peak rate of
heat release, which generally expresses the maximum intensity of a
fire. The thermoplastic composition may, for example, exhibit a
peak heat release rate of about 200 kW/m.sup.2 or less, in some
embodiments from about 10 to about 180 kW/m.sup.2, and in some
embodiments, from about 20 to about 150 kW/m.sup.2, as measured by
a cone calorimeter in accordance with ASTM E1354-11b. Another
property that represents the flammability of the composition is the
maximum average rate of heat emission, which expresses the
sustained heat supplied by combustion of the composition. The
thermoplastic composition of the present invention may, for
example, exhibit a maximum average rate of heat emission of about
150 kW/m.sup.2 or less, in some embodiments from about 10 to about
100 kW/m.sup.2, in some embodiments, from about 20 to about 80
kW/m.sup.2, as measured by a cone calorimeter in accordance with
ASTM E1354-11b.
[0064] In addition to possessing flame retardant properties, the
thermoplastic composition may also exhibit a relatively low degree
of smoke production. For example, the thermoplastic composition may
exhibit a maximum smoke density ("D.sub.s") that is about 250 or
less, in some embodiments about 200 or less, and in some
embodiments, from about 5 to about 150, as determined at an
exposure period of 4 minutes in accordance with the smoke density
test as set forth in ASTM E662-09. The composition may also exhibit
an average specific extinction area (smoke production) of about
0.800 m.sup.2/g or less, in some about 0.500 m.sup.2/g or less, and
in some embodiments, from about 0.050 to about 0.450 m.sup.2/g, as
measured by a cone calorimeter in accordance with ASTM
E1354-11b.
II. Conduit
[0065] The conduit of the present invention generally includes an
elongate member that defines a hollow passageway for receiving at
least one cable, conductor, fluid, etc. The term "cable" may refer
to a single insulated conductor, or a group of conductors insulated
from each other and forming a stranded assembly that may be further
insulated by outside wrappings, such as, for example, metal wire
(e.g., copper wire), telephone line, fiber optic cable,
telecommunications cable, electrical transmission/distribution
lines, lines for promoting support of elevated structures (e.g.,
guide wires), etc. Signals carried by a cable may include
electrical and/or optical signals. The conduit may be used in a
wide variety of applications, such as buildings, oil wells, etc.
When employed in a building, for instance, the conduit may be used
to enclose riser cables, plenum cables, etc.
[0066] Referring to FIG. 1, one particular embodiment of a conduit
10 is shown that may be employed as a plenum raceway. The conduit
10 includes an elongate member 12 that has a first end portion 14
and a second end portion 16 opposing the first end portion 14. The
elongate member 12 may contain one or more multiple layers, one or
more of which may be formed by the thermoplastic composition of the
present invention. The elongate member 12 also defines a hollow
passageway 20 for receiving at least one cable 22 therethrough. The
passageway 20 has a cross-sectional dimension that is substantially
circular. Of course, any of a variety of other shapes may also be
employed. For example, the passageway 20 may have a polygonal
(e.g., square or rectangular) cross-sectional shape. The size of
the passageway 20 may also vary, such as from about 0.5 to about 2
inches. If desired, some or all of an outer surface 29 of the
elongate member 12 may be corrugated. For example, in FIG. 1, a
portion of the elongate member 12 is shown as having corrugations
26. However, this is by no means a required feature, and some or
all of the surface 29 may be substantially continuous along the
length of the elongate member 12.
[0067] Rather than being employed to enclose a communication cable
as shown in FIG. 1, the thermoplastic composition may also employed
in the cable itself. Referring to FIG. 2, for example, one
embodiment of the communication cable 22 of FIG. 1 is shown in more
detail. More particularly, the cable 22 may contain an elongated
jacket 112 having a circular cross-sectional shape that defines a
passageway 117, which receives a cable core 114 formed by a
plurality of individually insulated conductors 116 (e.g., copper
wire). In one particular embodiment, the thermoplastic composition
of the present invention may be used to form the jacket 112. In the
embodiment shown in FIG. 2, the jacket 112 is constructed of a
single layer. Alternatively, the jacket may be constructed of
multiple layers. In FIG. 3, for instance, a cable 222 is shown that
contains a jacket formed from an outer layer 224 and an inner layer
223. In certain embodiments, the outer layer 224 is formed from the
thermoplastic composition of the present invention, while the inner
layer 223 is formed from a metallic shield material. As shown, the
jacket itself may also enclose at least one conductor 216 that
contains a conductive core 218 surrounded by insulation layers 218
and 220.
Test Methods
[0068] Limiting Oxygen Index:
[0069] The Limiting Oxygen Index ("LOI") may be determined by ASTM
D2863-10, which may be technically equivalent to ISO 4589-1,2. LOI
is the minimum concentration of oxygen that will just support
flaming combustion in a flowing mixture of oxygen and nitrogen.
More particularly, a specimen may be positioned vertically in a
transparent test column and a mixture of oxygen and nitrogen may be
forced upward through the column. The specimen may be ignited at
the top. The oxygen concentration may be adjusted until the
specimen just supports combustion. The concentration reported is
the volume percent of oxygen at which the specimen just supports
combustion.
[0070] Peak Heat Release Rate:
[0071] This value represents the peak heat release rate
(kW/m.sup.2) as determined in accordance with ASTM E1354-11b.
[0072] Maximum Average Rate of Heat Emission:
[0073] This value represents the maximum average rate of heat
emission (kW/m.sup.2) as determined in accordance with ASTM
E1354-11b.
[0074] Average Specific Extinction Area:
[0075] This value represents the average area of smoke (m.sup.2/kg)
generated during a flammability test conducted in accordance with
ASTM E1354-11b.
[0076] Melting Temperature:
[0077] The melting temperature ("Tm") may be determined by
differential scanning calorimetry ("DSC") as is known in the art.
The melting temperature is the differential scanning calorimetry
(DSC) peak melt temperature as determined by ISO Test No. 11357.
Under the DSC procedure, samples may be heated and cooled at
20.degree. C. per minute as stated in ISO Standard 10350 using DSC
measurements conducted on a TA Q2000 Instrument.
[0078] Melt Viscosity:
[0079] The melt viscosity may be reported as scanning shear rate
viscosity as determined in accordance with ISO Test No. 11443
(technically equivalent to ASTM D3835) at a shear rate of about
1200 s.sup.-1 and at a temperature of 316.degree. C. using a
Dynisco 7001 capillary rheometer. The rheometer orifice (die) may
have a diameter of 1 mm, a length of 20 mm, an L/D ratio of 20.1,
and an entrance angle of 180.degree.. The diameter of the barrel
may be 9.55 mm 0.005 mm and the length of the rod may be 233.4
mm.
[0080] Tensile Modulus, Tensile Stress (at Break and Yield Points),
and Tensile Strain (at Break and Yield Points):
[0081] Tensile properties may be tested according to ISO Test No.
527 (technically equivalent to ASTM D638). Modulus and strength
measurements may be made on the same test strip sample having a
length of 80 mm, thickness of 10 mm, and width of 4 mm. The testing
temperature may be 23.degree. C., and the testing speeds may be 1
or 5 mm/min.
[0082] Flexural Modulus and Flexural Stress (at 3.5% Strain):
[0083] Flexural properties can be tested according to ISO Test No.
178 (technically equivalent to ASTM D790). This test can be
performed on a 64 mm support span. Tests can be run on the center
portions of uncut ISO 3167 multi-purpose bars. The testing
temperature may be 23.degree. C. and the testing speed may be 2
mm/min.
[0084] Chlorine Content:
[0085] Chlorine content can be determined according to an elemental
analysis using Parr Bomb combustion followed by Ion
Chromatography.
[0086] The present invention may be better understood with
reference to the following examples.
Example 1
[0087] The ability to form a flame thermoplastic composition is
demonstrated. More particularly, the components listed in the table
below are mixed in a Werner Pfleiderer ZSK 25 co-rotating
intermeshing twin-screw extruder having a 25 mm diameter and eight
(8) different heated mixing zones (feed throat and Zones 1-7).
TABLE-US-00001 Components Sample Sample Sample Sample Sample Sample
Sample Sample Sample (% by weight) 1 2 3 4 5 6 7 8 9 Fortron .RTM.
79.45 75.46 63.47 75.46 63.47 75.46 63.47 59.45 59.45 0214 B1 (PPS)
Glycolube .RTM. 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 P Lotader .RTM.
20 18.99 15.98 18.99 15.98 18.99 15.98 10 15 AX8840 Shin-ETSU 0.25
0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 KBE-903 Aminosilane Melapur
.RTM. -- -- -- 5 20 -- -- 30 15 200 Melapur .RTM. -- 5 20 -- --
1.67 6.67 -- -- MC 15 Exolit .RTM. OP -- -- -- -- -- 3.33 13.3 --
-- 935 Kemgard -- -- -- -- -- -- -- -- 5 911B Firebrake -- -- -- --
-- -- -- -- 5 500
[0088] The fire-resisting system is supplied to a heated mixing
zone, while the polymer and remaining materials are supplied at the
feed throat. Once compounded, parts are then molded from each
sample on a Mannesmann Demag D100 NCIII injection molding machine
and tested. The results are set forth below.
TABLE-US-00002 Sample Sample Sample Sample Sample Sample Sample
Sample Sample Properties 1 2 3 4 5 6 7 8 9 Melting 278.6 279.2
279.6 278.5 278.2 279.4 279 279 281 Temp. (.degree. C.) Halogen 516
490 412 490 412 490 412 380 380 Content (ppm).sup.1 Melt Viscosity
3300 3393 5034 3863 5414 4598 4310 1295 2719 (316.degree. C., 1200
s.sup.-1) (poise) Limiting 44.2 44.2 42 50.1 53.3 44.2 49.8 57.9
49.5 Oxygen Index ("LOI") Tensile 1936 1955 2008 2042 2331 1982
2448 3207 2553 Modulus (MPa) Tensile 44.29 42.96 37.9 41.91 37.87
42.31 38.1 -- -- Stress at Yield (MPa) Tensile Strain 14.54 14.47
14.96 5.39 5.21 17.61 5.72 -- -- at Yield (%) Tensile 43.65 42.49
37.43 40.74 37.54 40.54 37.1 47.46 44.51 Stress at Break (MPa)
Tensile Strain 35.95 17.11 16.94 6.85 4.71 20.77 9.6 2.54 3.66 at
Break (%) Flexural 2320 2210 2427 2186 2633 2267 2700 3252 2725
Modulus (MPa) Flexural 61.06 56.21 56.65 57.79 63.71 58.43 64.1
83.64 70.36 Stress at 3.5% Strain (MPa) Peak Heat 200.7 -- -- --
121.15 137 134 139 Release Rate (kW/m.sup.2) Maximum 123.69 -- --
-- 85.47 -- 82 55 83 Average Rate of Heat Emission Specific 0.522
-- -- -- 0.435 -- 0.38 0.433 0.571 Extinction Area (m.sup.2/g)
.sup.1The Fortron .RTM. PPS 0214 B1 resin used herein has a
chlorine content of 649 ppm. The halogen content of the
thermoplastic composition is thus calculated on the basis that no
other halogens are present.
[0089] As indicated above, the samples of the present invention
have a high melting temperature and a high LOI value, as well as a
low peak heat release rate and low specific extinction area, all of
which are accomplished without sacrificing mechanical
properties.
Example 2
[0090] The ability to form a flame thermoplastic composition is
demonstrated. More particularly, the components listed in the table
below are mixed in a Werner Pfleiderer ZSK 25 co-rotating
intermeshing twin-screw extruder having a 25 mm diameter and eight
(8) different heated mixing zones (feed throat and Zones 1-7).
TABLE-US-00003 Components (% by weight) Sample 10 Fortron .RTM.
0205 B4 (PPS) 59.45 Glycolube .RTM. P 0.3 Lotader .RTM. AX8840 15
Shin-ETSU KBE-903 (Aminosilane} 0.25 Melapur .RTM. 200 5 Kemgard
.TM. 911B (Zinc Molybdate) 5 Fluon .TM. FL1690 (PTFE) 15
[0091] The fire-resisting system is supplied to a heated mixing
zone, while the polymer and remaining materials are supplied at the
feed throat. Once compounded, parts are then molded from each
sample on a Mannesmann Demag D100 NCIII injection molding machine
and tested. The results are set forth below.
TABLE-US-00004 Properties Sample 10 Melting Temp. (.degree. C.) 281
Melt Viscosity (316.degree. C., 1200 s.sup.-1) (poise) 280 Limiting
Oxygen Index ("LOI") 43.6 Tensile Modulus (MPa) 1946 Tensile Stress
at Break (MPa) 38 Tensile Strain at Break (%) 7.76 Flexural Modulus
(MPa) 1986 Flexural Stress at 3.5% Strain (MPa) 55.4 Peak Heat
Release Rate (kW/m.sup.2) 83 Maximum Average Rate of Heat Emission
58 Specific Extinction Area (m.sup.2/g) 0.11
Prophetic Example
[0092] The components listed in the table below may be mixed in a
Werner Pfleiderer ZSK 25 co-rotating intermeshing twin-screw
extruder having a 25 mm diameter and eight (8) different heated
mixing zones (feed throat and Zones 1-7).
TABLE-US-00005 Components (% by weight) Sample 11 Fortron .RTM.
0205 B4 (PPS) 54.55 Glycolube .RTM. P 0.3 Lotader .RTM. AX8840 15
Shin-ETSU KBE-903 (Aminosilane) 0.25 Melapur .RTM. 200 5 Kemgard
.TM. 911B (Zinc Molybdate) 5 Fluon .TM. FL1690 (PTFE) 15 Vicron
.TM. 15-15 (CaCO.sub.3) 5
[0093] The fire-resisting system may be supplied to a heated mixing
zone, while the polymer and remaining materials may be supplied at
the feed throat.
[0094] These and other modifications and variations of the present
invention may be practiced by those of ordinary skill in the art,
without departing from the spirit and scope of the present
invention. In addition, it should be understood that aspects of the
various embodiments may be interchanged both in whole or in part.
Furthermore, those of ordinary skill in the art will appreciate
that the foregoing description is by way of example only, and is
not intended to limit the invention so further described in such
appended claims.
* * * * *