U.S. patent application number 12/336358 was filed with the patent office on 2009-08-27 for polymer fiber containing flame retardant, process for producing the same, and material containing such fibers.
Invention is credited to Wouter Koen Harteveld, Hans Joachim Heinen, Robert Van Den Berg, Thomas Paul Von Kossak-Glowczewski.
Application Number | 20090214813 12/336358 |
Document ID | / |
Family ID | 38834967 |
Filed Date | 2009-08-27 |
United States Patent
Application |
20090214813 |
Kind Code |
A1 |
Van Den Berg; Robert ; et
al. |
August 27, 2009 |
POLYMER FIBER CONTAINING FLAME RETARDANT, PROCESS FOR PRODUCING THE
SAME, AND MATERIAL CONTAINING SUCH FIBERS
Abstract
A flame retardant polymer fiber, a process for making such a
fiber, and a material containing such fibers are provided. The
flame retardant polymer fiber is a high tenacity fiber formed of a
poly(trimethylene terephthalate) co-polymer containing a
trimethylene terephthalate monomer and a phosphorous containing
flame retardant monomer. The flame retardant PTT co-polymer fiber
is produced by a process in which the trimethylene terephthalate
monomer or its precursors and the phosphorous containing flame
retardant monomer or its precursors are combined to form the PTT
co-polymer in one or more pre-polymerization and polymerization
steps, and the PTT co-polymer is spun into a fiber. Materials
including such flame retardant PTT co-polymer fibers, e.g. carpets
and textiles, are also provided.
Inventors: |
Van Den Berg; Robert;
(Munich, DE) ; Harteveld; Wouter Koen; (Amsterdam,
NL) ; Heinen; Hans Joachim; (Gummerbach, DE) ;
Von Kossak-Glowczewski; Thomas Paul; (Gummersbach,
DE) |
Correspondence
Address: |
SHELL OIL COMPANY
P O BOX 2463
HOUSTON
TX
772522463
US
|
Family ID: |
38834967 |
Appl. No.: |
12/336358 |
Filed: |
December 16, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61014529 |
Dec 18, 2007 |
|
|
|
Current U.S.
Class: |
428/96 ; 264/103;
442/141; 525/441 |
Current CPC
Class: |
C10J 3/526 20130101;
C10J 2200/152 20130101; C10K 1/101 20130101; C10K 1/06 20130101;
C10J 3/84 20130101; C10K 1/10 20130101; Y02E 20/18 20130101; Y10T
428/23986 20150401; F28C 3/08 20130101; C10J 3/845 20130101; C10K
1/16 20130101; Y10T 442/2672 20150401; F28G 1/00 20130101 |
Class at
Publication: |
428/96 ; 525/441;
442/141; 264/103 |
International
Class: |
D03D 27/00 20060101
D03D027/00; C08L 67/00 20060101 C08L067/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 4, 2007 |
EP |
07115657.4 |
Claims
1. A flame retardant polyester fiber comprised of a polymer formed
of from 50 mol % to 99.9 mol % of a trimethylene terephthalate
component of formula (I) and from 0.1 mol % to 50 mol % of a
phosphorous containing component of formula (II) ##STR00014## where
p is from 1 to 2500, q is from 1 to 1250, and R.sub.1 is an alkyl
alcohol residuum having from 1 to 5 carbon atoms, an alkyl acid
residuum having from 1 to 5 carbon atoms, an alkyl ester residuum
having from 1 to 5 carbon atoms, or an oxygen atom; where the fiber
has a tenacity of at least 1.5 g/d.
2. The flame retardant polyester fiber of claim 1 further
comprising from 0.5 wt. % to 25 wt. % of a polyamide or a polyester
other than the polymer formed of the trimethylene terephthalate
component of formula (I) and the phosphorous containing component
of formula (II).
3. A material, comprising a plurality of fibers wherein at least 5%
of the fibers are comprised of a polymer comprised of from 50 mol %
to 99.9 mol % of a trimethylene terephthalate component of formula
(I) and from 0.1 mol % to 50 mol % of a phosphorous containing
component of formula (II) ##STR00015## where p is from 1 to 2500, q
is from 1 to 1250, and R.sub.1 is an alkyl alcohol residuum having
from 1 to 5 carbon atoms, an alkyl acid residuum having from 1 to 5
carbon atoms, an alkyl ester residuum having from 1 to 5 carbon
atoms, or an oxygen atom.
4. The material of claim 3 wherein the fibers comprised of the
trimethylene terephthalate component of formula (I) and the
phosphorous containing component of formula (II) have a tenacity of
at least 1.5 g/d.
5. The material of claim 3 wherein the material is a carpet.
6. The carpet material of claim 5 having a flame resistance such
that the probability that a methanamine tablet ignited on the
carpet material in a pill test will char the carpet material a
distance of at most 7.62 cm from the tablet is at least 85%.
7. The carpet material of claim 5 wherein the carpet material has
an average minimum radiant flux of at least 0.22 watts per square
centimeter.
8. The material of claim 3 wherein the material is a textile.
9. A process for producing a flame retardant polyester fiber,
comprising: providing a flame retardant poly(trimethylene
terephthalate) co-polymer comprising from 50 mol % to 99.9 mol % of
a trimethylene terephthalate component of formula (I) and from 0.1
mol % to 50 mol % of a phosphorous containing component of formula
(II) ##STR00016## where p is from 1 to 2500, q is from 1 to 1250,
and R.sub.1 is an alkyl alcohol residuum having from 1 to 5 carbon
atoms, an alkyl acid residuum having from 1 to 5 carbon atoms, an
alkyl ester residuum having from 1 to 5 carbon atoms, or an oxygen
atom; heating the poly(trimethylene terephthalate) co-polymer to a
temperature of from 240.degree. C. to 280.degree. C. to melt the
co-polymer; and passing the molten poly(trimethylene terephthalate)
co-polymer through a spinneret to form a fiber.
10. The process of claim 9 further comprising providing a
supplementary polymer selected from the group consisting of a
polyamide, a polyester different from the poly(trimethylene
terephthalate) co-polymer, and mixtures thereof, mixing the
supplementary polymer and the poly(trimethylene terephthalate)
co-polymer at a temperature of from 240.degree. C. to 280.degree.
C. to form a molten mixture of the supplementary polymer and the
co-polymer, and passing the molten mixture through a spinneret to
form a fiber.
11. The process of claim 9 wherein the fiber is a filament and
further comprising combining the filament with a plurality of
filaments comprised of the trimethylene terephthalate component of
formula (I) and the phosphorous containing component of formula
(II) and forming the combined filaments into a fully oriented
yarn.
12. The process of claim 9 wherein the fiber is a filament and
further comprising combining the filament with a plurality of
filaments comprised of the trimethylene terephthalate component of
formula (I) and the phosphorous containing component of formula
(II) and forming the combined filaments into a partially oriented
yarn.
13. The process of claim 9 wherein the fiber is a filament further
comprising combining the filament with a plurality of filaments
comprised of the trimethylene terephthalate component of formula
(I) and the phosphorous containing component of formula (II) and
forming the combined filaments into an undrawn yarn.
14. The process of claim 13 further comprising drawing and
texturing the undrawn yarn, and cutting the drawn, textured yarn
into staple fibers having a length of from 0.5 cm to 15 cm.
15. The process of claim 9 wherein the fiber is a filament further
comprising combining the filament with a plurality of filaments
comprised of the trimethylene terephthalate component of formula
(I) and the phosphorous containing component of formula (II) and
forming the filaments into a bulk continuous filament yarn.
Description
[0001] This application claims the benefit of U.S. Provisional
Application No. 61/014,529, filed Dec. 18, 2007, which is
incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention is directed to a polymer fiber
containing a flame retardant, a process for producing the fiber,
and materials containing the fiber. More particularly, the present
invention is directed to a polymer fiber containing a flame
retardant co-polymer component, a process for producing the same,
and a material containing such fibers.
BACKGROUND OF THE INVENTION
[0003] Flame retardants are frequently added to or incorporated in
polymers to provide flame retardant properties to the polymers. The
flame retardant polymers may then be spun into fibers that may be
used in applications in which resistance to flammability is
desirable, for example, in textile or carpet applications.
[0004] A large variety of compounds have been used to provide flame
retardancy to polymers. For example, numerous classes of
phosphorous containing compounds, halogen containing compounds, and
nitrogen containing compounds have been utilized as flame
retardants in polymers. Classes of halogen containing compounds
that have been used a flame retardants in polymers include
polyhalogenated hydrocarbons. Classes of phosphorous containing
compounds that have been used as flame retardants in polymers
include inorganic phosphorous compounds such as red phosphorous,
monomeric organic phosphorous compounds, orthophosphoric esters or
condensates thereof, phosphoric ester amides, phosphonitrilic
compounds, phosphine oxides (e.g. triphenylphosphine oxides), and
metal salts of phosphinic, phosphoric, and phosphonic acids. The
metal salts of phosphinic acids (metal salt phosphinates) that have
been utilized as flame retardants in polymers comprise a large
variety of compounds themselves, including monomeric, oligomeric,
and polymeric species with one, two, three, or four phosphinate
groups per coordination center including metals selected from
beryllium, magnesium, calcium, strontium, barium, titanium,
zirconium, vanadium, antimony, bismuth, chromium, molybdenum,
tungsten, manganese, iron, ruthenium, cobalt, rhodium, iridium,
nickel, platinum, palladium, copper, silver, zinc, cadmium,
mercury, aluminum, tin, and lead.
[0005] Such flame retardant compounds have been used in a wide
variety of polymers. For example, phosphorous containing compounds
have been used as flame retardants in polymers such as polymers of
mono- and di-olefins such as polypropylene, polyisobutylene,
polyisoprene, and polybutadiene; aromatic homopolymers and
copolymers derived from vinyl aromatic monomers such as styrene,
vinylnaphthalene, and p-vinyltoluene; hydrogenated aromatic
polymers such as polycyclohexylethylene; halogen containing
polymers such as polychloroprene and polyvinylchloride; polymers
derived from .alpha.,.beta.-unsaturated acids and derivatives
thereof such as polyacrylates and polyacrylonitriles; polyamides
such as poly(.epsilon.-caproamide) sold as NYLON-6 and
poly(hexamethylene adipamide) sold as NYLON-6,6; polysulfones; and
polyesters such as polyethylene terephthalate (PET) and
polybutylene terephthalate (PBT).
[0006] Poly(trimethylene terephthalate) ("PTT") is a polyester that
has recently been commercially developed as a result of the recent
availability of commercial quantities of 1,3-propanediol, a
requisite compound for forming PTT. PTT has an array of desirable
characteristics when used in fiber applications relative to other
polymers used in fiber applications such as polyamides,
polypropylenes, and its polyester counterparts PET and PBT, such as
soft touch, good stain resistance, and resilience and shape
recovery due to its spring-like molecular structure.
[0007] It is desirable to provide PTT fibers with flame retardant
properties by incorporating a flame retardant in PTT fibers.
Incorporation of a flame retardant in a PTT fiber, however, has
proven difficult since PTT fibers containing effective amounts of
flame retardants are prone to breakage during spinning of the fiber
due to the presence of the flame retardant in the PTT. As a result,
a PTT fiber having a high tenacity, for example a tenacity of at
least 1.5 gram per denier (g/d), and an effective amount of flame
retardant has proven elusive. A PTT fiber having a high tenacity is
necessary to produce quality yarns, carpets, and textiles from the
PTT fiber. It would be useful to have a PTT fiber containing a
highly effective flame retardant in which the fiber has a tenacity
of at least 1.5 g/d, where the fiber has reduced flame retardant
induced breakage when melt spun relative to presently available PTT
fibers containing flame retardants.
[0008] U.S. Pat. Nos. 4,180,495; 4,208,321; and 4,208,322 provide
poly(metal phosphinate) flame retardants that may be added to
polyester resins, polyamide resins, or polyester-polyamide resins.
Among several other applications, the resins may be spun into
fibers and thereafter be made into fabric and clothing. One of the
polyester resins to which such flame retardants may be added is
PTT. The list of poly(metal phosphinate) flame retardants that may
be added to the polyester, polyamide, or polyester-polyamide resins
is extensive, and includes the metal salts of phosphinic acids
(metal salt phosphinates) listed above--e.g. monomeric, oligomeric,
and polymeric species with one, two, three, or four phosphinate
groups per coordination center including metals selected from
beryllium, magnesium, calcium, strontium, barium, titanium,
zirconium, vanadium, antimony, bismuth, chromium, molybdenum,
tungsten, manganese, iron, ruthenium, cobalt, rhodium, iridium,
nickel, platinum, palladium, copper, silver, zinc, cadmium,
mercury, aluminum, tin, and lead. The poly(metal phosphinate) flame
retardants may be utilized in the polymers in an amount from 0.25
to 30 parts by weight per 100 parts by weight of polymer resin.
These references, however, do not provide a PTT fiber having a high
tenacity, e.g. a tenacity of at least 1.5 g/d, containing an
effective amount of flame retardant since they do not provide a PTT
fiber that is not prone to breakage in melt spinning due to the
presence of the flame retardant in the PTT when the flame retardant
is present in amounts sufficient to effectively reduce the
flammability of the fiber.
[0009] Co-polymers comprising a polyester and a flame retardant
monomer are also known. Synthesis and Characterization of
Copolyesters Containing the Phosphorous Linking Pendent Groups, J.
App. Polymer Sci., Vol. 72, 109-122 (1999) provides a flame
retardant poly(ethylene terephthalate)-co-poly(ethylene
9,10-dihydro-10[2,3-di-(hydroxy
carbonyl)propyl]-10-phosphaphenanthrene-10-oxide) [PET-co-PEDDP]
co-polymer. The flame retardant PET-co-PEDDP co-polymer provides
improved flame retardant characteristics relative to a PET
homopolyester. The PET-co-PEDDP co-polymer, however, has a
significantly decreased tensile strength relative to the PET
homopolyester, where inclusion of 0.7 wt. % of phosphorous (from
the flame retardant) in the co-polymer reduces that tensile
strength by a third, and increasing levels of phosphorous from the
flame retardant further decrease the tensile strength of the
co-polymer. The tensile strength of a polymer is related to its
tenacity, as both are measures of tensile stress-therefore, the
PET-co-PEDDP co-polymer would be expected to have a significantly
lower tenacity than a PET homopolyester since the co-polymer has
significantly decreased tensile strength relative to the
homopolyester.
SUMMARY OF THE INVENTION
[0010] In one aspect, the invention is directed to a flame
retardant polyester fiber comprised of a polymer formed of from 50
mol % to 99.9 mol % of a trimethylene terephthalate component of
formula (I) and from 0.1 mol % to 50 mol % of a phosphorous
containing component of formula (II)
##STR00001##
where p is from 1 to 2500, q is from 1 to 1250, and R.sub.1 is an
alkyl alcohol residuum having from 1 to 5 carbon atoms, an alkyl
acid residuum having from 1 to 5 carbon atoms, an alkyl ester
residuum having from 1 to 5 carbon atoms, or an oxygen atom; where
the fiber has a tenacity of at least 1.5 g/d.
[0011] In another aspect, the invention is directed to a material
comprising a plurality of fibers wherein at least 5% of the fibers
are comprised of a polymer comprised of from 50 mol % to 99.9 mol %
of a trimethylene terephthalate component of formula (I) and from
0.1 mol % to 50 mol % of a phosphorous containing component of
formula (II)
##STR00002##
where p is from 1 to 2500, q is from 1 to 1250, and R.sub.1 is an
alkyl alcohol residuum having from 1 to 5 carbon atoms, an alkyl
acid residuum having from 1 to 5 carbon atoms, an alkyl ester
residuum having from 1 to 5 carbon atoms, or an oxygen atom.
[0012] In another aspect, the invention is directed to a process
for producing a flame retardant polyester fiber, comprising:
[0013] providing a flame retardant poly(trimethylene terephthalate)
co-polymer comprising from 50 mol % to 99.9 mol % of a trimethylene
terephthalate component of formula (I) and from 0.1 mol % to 50 mol
% of a phosphorous containing component of formula (II)
##STR00003##
where p is from 1 to 2500, q is from 1 to 1250, and R.sub.1 is an
alkyl alcohol residuum having from 1 to 5 carbon atoms, an alkyl
acid residuum having from 1 to 5 carbon atoms, an alkyl ester
residuum having from 1 to 5 carbon atoms, or an oxygen atom;
[0014] heating the poly(trimethylene terephthalate) co-polymer to a
temperature of from 240.degree. C. to 280.degree. C. to melt the
co-polymer; and
[0015] passing the molten poly(trimethylene terephthalate)
co-polymer through a spinneret to form a fiber.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Advantages of the present invention will become apparent to
those skilled in the art with the benefit of the following detailed
description and upon reference to the accompanying drawings in
which:
[0017] FIG. 1 is a schematic of a process for producing a fiber of
the present invention incorporated into a yarn.
[0018] FIG. 2 is a schematic of a process for producing a fiber of
the present invention as a bulk continuous filament.
DETAILED DESCRIPTION OF THE INVENTION
[0019] The present invention provides a flame retardant polymer
fiber comprised of a poly(trimethylene terephthalate) co-polymer
containing a flame retardant phosphorous component and trimethylene
terephthalate as monomers in the co-polymer. Surprisingly the
co-polymer fiber does not have significantly reduced tenacity
relative to a PTT homopolymer fiber when the phosphorous containing
component is included in the co-polymer fiber in an amount
sufficient to provide effective flame retardancy to the fiber. The
PTT co-polymer fiber of the present invention may exhibit a
tenacity of at least 1.5 grams/denier (hereinafter "g/d"), or at
least 1.6 g/d, or at least 1.7 g/d. The flame retardant PTT
co-polymer fiber's maintenance of a relatively high tenacity as
compared with a PTT homopolymer was unexpected since analogous
(e.g. containing the same or substantially similar flame retardant
monomer) flame retardant poly(ethylene terephthalate) (PET)
co-polymers exhibit a substantial decrease of tensile strength
relative to a PET homopolymer. Tensile strength and tenacity are
each measures of tensile stress, so a significant decrease in
tensile strength in the flame retardant PET co-polymer relative to
a PET homopolymer would be expected to correlate to a similar
decrease in tenacity in an analogous flame retardant PTT co-polymer
relative to a PTT homopolymer.
[0020] The high tenacity flame retardant PTT co-polymer fiber of
the present invention has sufficient strength to be formed into
flame retardant yarns that may be used to produce flame retardant
materials such as carpets and textiles. Unlike PTT polymers
combined with flame retardant additives, the flame retardant PTT
co-polymer fiber of the invention has a flame retardant component
incorporated into the polymer itself so the flame retardancy of the
polymer is uniformly distributed in the fiber, and the flame
retardant is not subject to being gradually removed from the fiber.
Further, the high tenacity flame retardant PTT co-polymer fiber may
be spun without significant fiber breakage due to either the low
tenacity/tensile stress of the fiber or due to particulate flame
retardant additives.
[0021] The flame retardant PTT co-polymer fiber of the present
invention is comprised of a PTT containing co-polymer comprising at
least 50 mol %, or at least 80 mol %, or at least 95 mol %, or at
least 97 mol %, or from 50 mol % to 99.9 mol %, or from 70 mol % to
99.5 mol %, or from 80 mol % to 95 mol % of a trimethylene
terephthalate monomer, shown as Formula (I)
##STR00004##
and greater than 0 mol % but at most 50 mol %, or at most 30 mol %,
or at most 20 mol %, or at most 10 mol %, or from 0.1 mol % to 50
mol %, or from 0.5 mol % to 30 mol %, or from 5 mol % to 20 mol %
of a phosphorous containing monomer of formula (II).
##STR00005##
[0022] In formula (I), p may be from 1 to 2500, and preferably is
from 4 to 250. In formula (II), q may be from 1 to 1250, or from 1
to 10, and preferably is from 1 to 5. In formula (II), R.sub.1 may
be an alkyl alcohol residuum having from 1 to 5 carbon atoms, an
alkyl acid residuum having from 1 to 5 carbon atoms, an alkyl ester
residuum having from 1 to 5 carbon atoms, or an oxygen atom. An
alkyl alcohol residuum, as used herein, has the structure of
--[R.sub.2--O]--, where R.sub.2 is a branched or linear hydrocarbon
comprising 1 to 5 carbon atoms. An alkyl acid residuum and an alkyl
ester residuum, as used herein, may have the structure of
##STR00006##
where R.sub.3 is a branched or linear hydrocarbon comprising 1 to 4
carbon atoms. In one embodiment, R.sub.1 may be
--[CH.sub.2--CH.sub.2--CH.sub.2--O]--. In another embodiment,
R.sub.1 may be --[CH.sub.2--CH.sub.2--O]--. In another embodiment,
R.sub.1 may be
##STR00007##
[0023] The flame retardant PTT containing co-polymer fiber of the
present invention may also contain minor amounts of monomers other
than the trimethylene terephthalate component of formula (I) and
the phosphorous containing component of formula (II). Such monomers
include, but are not limited to, esterification products of one or
more diols selected from the group consisting of ethylene glycol,
1,3-propanediol, 1,4-butanediol, 1,4-butenediol, and 1,4
cyclohexanedimethanol with a dicarboxylic acid selected from the
group consisting of oxalic acid, succinic acid, phthalic acid,
2,6-naphthalenedicarboxylic acid, 5-sodiumsulfoisophthalic acid,
isophthalic acid, adipic acid, terephthalic acid (except with
1,3-propanediol, which would form a trimethylene terephthalate
monomer), and mixtures thereof; or transesterification products of
one or more of the diols listed above with one or more esters of
one or more of the dicarboxylic acids listed above. The PTT
containing co-polymer fiber may contain up to 25 mol % of these
monomers, or may contain at most 15 mol %, or at most mol %, or at
most 5 mol % of these monomers. The flame retardant PTT containing
co-polymer fiber of the present invention may also contain no
monomers other than the trimethylene terephthalate component of
formula (I) and the phosphorous containing component of formula
(II).
[0024] Other polymers may be included in minor amounts in the flame
retardant PTT containing co-polymer fiber of the present invention
along with the flame retardant PTT containing co-polymer. Polymers
that may also be included in the flame retardant PTT containing
co-polymer fiber include polysulfones, polyesters such as
poly(ethylene terephthalate), poly(butylene terephthalte),
poly(ethylene naphthalate) and poly(trimethylene naphthalate), and
polyamides such as poly(.epsilon.C-caproamide) (NYLON-6) and
poly(hexamethylene adipamide) (NYLON-6,6). The polymers that may be
included in the fiber of the present invention with the flame
retardant PTT containing co-polymer do not exceed 25 wt. %, or 15
wt. %, or 10 wt. %, or 5 wt. % of the composition. In an embodiment
of the composition of the invention, the flame retardant PTT
containing co-polymer may be present in the fiber in a weight ratio
to other polymers of at least 3:1, or at least 4:1, or at least
5:1, or at least 6:1. In an embodiment, no other polymer is present
in the flame retardant PTT containing co-polymer fiber other than
the PTT containing co-polymer itself.
[0025] The flame retardant PTT co-polymer fiber of the present
invention has a tenacity of at least 1.5 g/d. In an embodiment of
the fiber of the present invention, the fiber may have a tenacity
of at least 1.6 g/d, or at least 1.7 g/d. Tenacity, for purposes of
the present invention, is measured with a Statimat ME tester with a
load cell of 100 newtons. A pretension force of 0.05 g/d is applied
to the fiber/yarn with a gauge length of 110 mm, and the tenacity
is measured at a cross-head speed of 300 mm/min. The test is
repeated ten times on segments of a selected yarn or fiber, and the
average value of the ten measurements is defined as the tenacity of
the yarn or fiber for purposes of the present invention.
[0026] The flame retardant PTT co-polymer fiber of the invention
may contain dispersed therein minor amounts of a flame retardant
component that does not have a melting point equal to or below
280.degree. C., which is defined for purposes of the present
invention as a "non-fusible flame retardant component". The
non-fusible flame retardant component, if present, does not have a
melting point equal to or below 280.degree. C., although the
non-fusible flame retardant component may, but does not
necessarily, have a melting point above 280.degree. C. since the
non-fusible flame retardant component may decompose rather than
melt at temperatures above 280.degree. C. Such non-fusible flame
retardants may include: phosphinate metal salts of the formula
(III) that do not melt at or below a temperature of 280.degree.
C.
##STR00008##
[0027] where R.sub.4 and R.sub.5 may be identical or different, and
are C.sub.1-C.sub.18 alkyl, linear or branched, and/or aryl, M is
Mg, Ca, Al, Sb, Ge, Ti, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, or K, and m
is from 1 to 4; other phosphorous containing compounds that are
non-fusible at a temperature of equal to or below 280.degree. C.,
including inorganic phosphorous compounds such as red phosphorous;
monomeric organic phosphorous compounds; orthophosphoric esters or
condensates thereof; phosphoric ester amides; phosphonitrilic
compounds; phosphine oxides (e.g. triphenylphosphine oxides); metal
salts of phosphoric and phosphonic acids; diphosphinic salts;
nitrogen containing compounds such as benzoguanamine compounds,
ammonium polyphosphate, and melamine compounds such as melamine
borate, melamine oxalate, melamine phosphate, melamine
pyrophosphate, polymeric melamine phosphate, and melamine
cyanurate; and polyhalogenated hydrocarbons.
[0028] If present, the non-fusible flame retardant component in the
fiber is present as a minor component of the flame retardant PTT
co-polymer fiber so that the non-fusible flame retardant will not
negatively affect the melt spinning of the fiber by inducing
breakage in the fiber as it is spun. The non-fusible flame
retardant component may comprise from 0 wt. % to 5 wt. %, or from 0
wt. % to 2.5 wt. %, or from 0 wt. % to 1 wt. % of the flame
retardant PTT co-polymer fiber.
[0029] If present, the non-fusible flame retardant component in the
fiber may be particulate. The particle size of the non-fusible
flame retardant component of the fiber of the invention may range
up to a mean particle size of 150 .mu.m. In an embodiment, the mean
particle size of the non-fusible flame retardant component may be
at most 10 .mu.m, or the non-fusible flame retardant may contain
nanoparticles and may have a mean particle size of at most 1 .mu.M.
Smaller mean particle size of the non-fusible flame retardant in
the fiber provides at least two benefits: 1) a more homogeneous
dispersion of the particulate flame retardant in the fiber; and 2)
reduced breakage in melt spinning the fibers as a result of few or
no large particulates in the polymer melt as it is spun into the
fiber.
[0030] In an embodiment, the flame retardant PTT co-polymer fiber
of the present invention may contain dispersed therein minor
amounts of a flame retardant component that has a melting point
equal to or below 280.degree. C., which is defined for purposes of
the present invention as a "fusible flame retardant component". The
fusible flame retardant component may be at least one flame
retardant fusible phosphinate metal salt having a melting point of
equal to or below 280.degree. C., or below 270.degree. C., or below
250.degree. C., or below 230.degree. C., or below 200.degree. C.,
or below 180.degree. C.
[0031] The flame retardant fusible phosphinate metal salt(s) may be
any phosphinate metal salt having the structure shown in formula
(IV) and having a melting point equal to or below 280.degree. C.,
or below 270.degree. C., or below 250.degree. C., or below
230.degree. C., or below 200.degree. C., or below 180.degree.
C.
##STR00009##
[0032] In formula (IV), R.sub.1 and R.sub.2 may be identical or
different, and are C.sub.1-C.sub.18 alkyl, linear or branched,
and/or aryl, M is Mg, Ca, Al, Sb, Ge, Ti, Fe, Zr, Ce, Bi, Sr, Mn,
Li, Na, or K, and m is from 1 to 4. The flame retardant fusible
phosphinate metal salt must have a melting point equal to or below
280.degree. C., or below 270.degree. C., or below 250.degree. C.,
or below 230.degree. C., or below 200.degree. C., or below
180.degree. C. so that it may be melted and dispersed in the PTT
co-polymer at a temperature that will not substantially degrade the
co-polymer.
[0033] In a preferred embodiment, the flame retardant fusible
phosphinate metal salt is a zinc phosphinate having a melting point
equal to or below 280.degree. C., or below 270.degree. C., or below
250.degree. C., or below 230.degree. C., or below 200.degree. C.,
or below 180.degree. C. and having the structure of formula (IV)
where R.sub.1 and R.sub.2 are identical or different and are
hydrogen, C.sub.1-C.sub.18 alkyl, linear or branched, and/or aryl,
M is zinc, and m is 2. In one embodiment the zinc phosphinate has a
melting point of equal to or below 280.degree. C., or below
270.degree. C., or below 250.degree. C., or below 230.degree. C.,
or below 200.degree. C., or below 180.degree. C. and is of the
formula (IV), where R.sub.1 and R.sub.2 are identical or different
and are methyl, ethyl, isopropyl, n-propyl, t-butyl, n-butyl, or
phenyl, M is zinc, and m is 2. In a preferred embodiment, the zinc
phosphinate is selected from the group consisting of zinc
diethylphosphinate, zinc dimethylphospinate, zinc
methylethylphosphinate, zinc diphenylphosphinate, zinc
ethylbutylphosphinate, and zinc dibutylphosphinate. In a most
preferred embodiment, the zinc phosphinate is zinc
diethylphosphinate.
[0034] If present, the fusible flame retardant component is present
as a minor component of the flame retardant PTT co-polymer fiber.
The fusible flame retardant component may comprise from 0 wt. % to
5 wt. %, or from 0 wt. % to 2.5 wt. %, or from 0 wt. % to 1 wt. %
of the flame retardant PTT co-polymer fiber. In an embodiment, the
flame retardant PTT co-polymer fiber may contain minor amounts of
both a fusible flame retardant component and a non-fusible flame
retardant component. If both a fusible flame retardant component
and a non-fusible flame retardant component are present in the
flame retardant PTT co-polymer fiber, the combined fusible and
non-fusible flame retardant components may comprise up to 5 wt. %,
or up to 2.5 wt. %, or up to 1 wt. % of the flame retardant PTT
co-polymer fiber.
[0035] In an embodiment of the invention, the flame retardant PTT
co-polymer fiber may contain a filler. "Filler" as the term is used
herein is defined as "a particulate or fibrous material having no
flame retardant activity". Too much filler may negatively affect
the melt spinning of the fiber of the present invention by inducing
breakage in the fiber as it is spun, therefore, the fiber may
contain from 0 wt. % to 5 wt. % filler, or may contain from 0 wt. %
to 3 wt. % filler. In an embodiment of the fiber of the present
invention, a filler may be included in the fiber as a delusterant.
A preferred filler for inclusion in the fiber as a delusterant is
titanium dioxide. Other examples of filler materials that may be
included in the fiber include fibrous materials such as glass
fiber, asbestos fiber, carbon fiber, silica fiber, fibrous
woolastonite, silica-alumina fiber, zirconia fiber, potassium
titanate fiber, metal fibers, and organic fibers with melting
points above 300.degree. C.; and particulate or amorphous materials
such as carbon black, white carbon, silicon carbide, silica, powder
of quartz, glass beads, glass powder, milled fiber, silicates such
as calcium silicate, aluminum silicate, clay, and diatomites, metal
oxides such as iron oxide, zinc oxide, and alumina, metal
carbonates such as calcium carbonate and magnesium carbonate, metal
sulfates such as calcium sulfate and barium sulfate, and metal
powders.
[0036] In an embodiment, the flame retardant PTT co-polymer fiber
of the present invention may contain one or more modifying agents
to provide selected properties to the fiber. "Modifying agent", as
the term is used herein, is defined as a material useful to modify
the physical, chemical, color, or electrical characteristics of the
flame retardant PTT co-polymer fiber, excluding the filler
materials and non-fusible flame retardants discussed above.
Modifying agents may include conventional antioxidants, lubricants,
dyes and other colorants, UV absorbers, and antistatic agents.
[0037] The flame retardant PTT co-polymer fiber of the present
invention may be undrawn, partially oriented, or fully oriented
depending on the conditions used to produce the fiber. An undrawn
fiber of the present invention is defined herein as a fiber
comprising a PTT co-polymer as described above having an elongation
to break of at least 120%. The undrawn fiber may have a
birefringence of less than 0.3 or less than 0.2. A partially
oriented fiber of the present invention is defined herein as a
fiber comprising a PTT co-polymer as described above having an
elongation to break of from 50% up to 120%. The partially oriented
fiber may have a birefringence of from 0.3 up to 0.9. A fully
oriented fiber of the present invention is defined herein as a
fiber comprising a PTT co-polymer as described above having an
elongation to break of up to 50%. The fully oriented fiber may have
a birefringence of greater than 0.9.
[0038] The flame retardant PTT co-polymer fiber of the present
invention has fiber-like dimensions, namely, that the length of the
fiber is much greater than the width or diameter of the fiber. The
fiber has a length of at least 100 times the width of the fiber,
and, in one embodiment, has a length of at least 1000 times the
width of the fiber. In one embodiment the fiber may be a filament,
e.g. a fiber of extreme length. In one embodiment the fiber is a
bulk continuous filament in which the filament has been textured,
e.g. by jet air texturing, to provide the filament with bulk. In
another embodiment, the fiber may be a staple fiber having a length
of from 0.5 cm to 15 cm (0.2 in. to 6 in.).
[0039] In one aspect, the present invention is directed to a
process for producing the fiber of the present invention.
[0040] In an embodiment, the fiber may be produced by
co-polymerizing a trimethylene terephthalate containing material
and a phosphorous containing compound of formula (V)
##STR00010##
where R.sub.6 and R.sub.7 may be the same or different and are a
hydrogen atom, an alkyl hydrocarbon group having from 1 to 5
carbons, or an alkyl alcohol group having from 1 to 5 carbons and
one or more alcohol substituents to form a flame retardant PTT
containing polymer (the PTT co-polymer) having an intrinsic
viscosity of at least 0.7 dl/g, then passing the PTT co-polymer in
a molten phase through a spinneret to form the fiber.
[0041] In an embodiment, the trimethylene terephthalate containing
material and the phosphorous containing compound of formula (V) may
be contacted at a temperature of from 230.degree. C. to 280.degree.
C. and a pressure of from 0.01 kPa to 5 kPa (0.1 mbar to 50 mbar)
to co-polymerize the trimethylene terephthalate containing material
and the phosphorous containing compound. In an embodiment, the
amounts of the trimetheylene terephthalate containing material and
the phosphorous containing compound of formula (V) utilized in the
co-polymerization may be selected to provide a mole ratio of
trimethylene terephthalate to phosphorous containing compound of
from 1:1 to 999:1.
[0042] In an embodiment, the flame retardant PTT containing polymer
for use in forming the fiber may be produced by 1) reacting
terephthalic acid with 1,3-propanediol to form a trimethylene
terephthalate containing material which may comprise trimethylene
terephthalate and/or an oligomer thereof (the esterification step);
and 2) co-polymerizing the trimethylene terephthalate containing
material with a phosphorous containing compound of formula (V) (the
co-polymerization step).
[0043] In the esterification step, the pressure may be adjusted to
and maintained in a range of from 70 kPa to 550 kPa (0.7 bar to 5.5
bar) and the temperature may be adjusted to and maintained in the
range of from 230.degree. C. to 280.degree. C., or from 240.degree.
C. to 270.degree. C. In an embodiment of the process, the
instantaneous concentration of unreacted 1,3-propanediol in the
reaction mass in the esterification step may be kept low to
minimize formation of dipropyleneglycol by regulation of the
reactant feeds--e.g. 1,3-propanediol and terephthalic acid may be
regulated such that they are added to the reaction mass in a molar
ratio of 1.15:1 to 2.5:1 to minimize formation of dipropylene
glycol--and the reaction pressure may be kept low, e.g. less than
300 kPa absolute (3 bar absolute), to remove excess unreacted
1,3-propanediol from the reaction medium in the reaction overhead
gases.
[0044] In an embodiment, minor amounts of other compounds may be
included in the esterification step that may be incorporated into
the trimethylene terephthalate containing material. For example,
compounds such as ethylene glycol, 1,4 butanediol, 1,4-butenediol,
1,4-cyclohexanedimethanol, oxalic acid, succinic acid, phthalic
acid, 2,6-naphthalenedicarboxylic acid, 5-sodiumsulfoisophthalic
acid, isophthalic acid, and/or adipic acid may be included in the
esterification step. Such compounds may be included in amounts that
they comprise, along with any other such compounds utilized in the
co-polymerization step, at most 25 mol %, or at most 15 mol %, or
at most 10 mol %, or at most 5 mol % of the final PTT containing
co-polymer composition to be spun into fiber.
[0045] An esterification catalyst may be used to promote the
esterification reaction. Esterification catalysts useful for
promoting the esterification reaction include titanium and
zirconium compounds, including titanium alkoxides and derivatives
thereof such as tetra(2-ethylhexyl)titanate, tetrastearyl titanate,
diisopropoxy-bis(acetylacetonato)titanium, tributyl
monacetyltitanate, triisopropyl monoacetyltitanate;
di-n-butoxy-bis(triethanolaminoato) titanium, tetrabenzoic acid
titanate, and titanium tetrabutoxide; titanium complex salts such
as alkali titanium oxalates and malonates, potassium
hexafluorotitanate and titanium complexes with hydroxycarboxylic
acids such as tartaric acid, citric acid, or lactic acid, catalysts
such as titanium dioxide/silicon dioxide co-precipitate and
hydrated alkaline-containing titanium dioxide; and the
corresponding zirconium compounds. Catalysts of other metals, such
as antimony, tin, and zinc, may also be used. A preferred catalyst
for use in promoting the esterification reaction is titanium
tetrabutoxide. The esterification catalyst may be provided to the
esterification reaction mass in an amount effective to catalyze the
esterification, and may be provided in an amount in the range of 5
to 250 ppm (metal), or in the range of 10 ppm to 100 ppm (metal),
based on the weight of the final PTT containing co-polymer
composition to be spun into fiber.
[0046] The esterification may be carried out in stages in a single
or multiple vessels at one or more temperatures and/or pressures
with one or more catalysts or catalyst amounts present in each
stage. For example, a two-stage esterification step may include a
first stage carried out in a first esterification vessel at or a
little above atmospheric pressure in the presence of 5 to 50 ppm
titanium catalyst and a second stage carried out in a second
esterification vessel at or below atmospheric pressure with an
additional 20 to 150 ppm of titanium catalyst added, where both
stages are conducted at a temperature of from 230.degree. C. to
280.degree. C., or from 240.degree. C. to 270.degree. C. The first
esterification stage may be conducted until a selected amount of
terephthalic acid is consumed, for example, at least 80%, or at
least 85%, or at least 90%, or at least 95%, or from 85% to 95%.
The second esterification stage may also be conducted until a
selected amount of terephthalic acid is consumed, for example, at
least 97%, or at least 98%, or at least 99%. In a continuous
process, the esterification steps may be carried out in separate
reaction vessels.
[0047] The conditions of the esterification may be selected to
produce a low molecular weight oligomeric esterification product
containing trimethylene terephthalate monomers. The oligomeric
trimethylene terephthalate containing material may have an
intrinsic viscosity of less than 0.2 dl/g, or from 0.05 to 0.15
dl/g (corresponding to a degree of polymerization of 3 to 10, e.g.
the value of p of formula (I) above is from 3 to 10).
[0048] In the co-polymerization step, the trimethylene
terephthalate containing material produced in the esterification
step may be contacted and mixed with the phosphorous containing
compound of formula (V) under conditions effective to induce
co-polymerization of the trimethylene terephthalate containing
material and the phosphorous containing compound. The
co-polymerization step may comprise several steps, for example: a
pre-polycondensation step in which the reaction mixture containing
the trimethylene terephthalate containing material and the
phosphorous containing compound of formula (V) may be processed
under selected temperature and pressure conditions to produce a
product having an intrinsic viscosity of from 0.15 to 0.4 dl/g
(corresponding to a degree of polymerization of 10 to 30, e.g., the
sum of the values of p of formula (I) and q of formula (II) is from
10 to 30); a melt polycondensation step in which the reaction
mixture comprising the product of the pre-polycondensation step or
alternatively, the trimethylene terephthalate containing material
from the esterification step and the phosphorous containing
compound of formula (V), may be processed under selected
temperature and pressure conditions to produce a melt co-polymer
product having an intrinsic viscosity of at least 0.25 dl/g or
least 0.7 dl/g, or at least 0.8 dl/g, or at least 0.9 dl/g; and a
solid state polymerization step in which the melt co-polymer may be
solidified, optionally dried and annealed, heated, and charged to a
solid state polymerization reactor for further polycondensation to
raise the intrinsic viscosity of the co-polymer. The
co-polymerization step may optionally contain fewer than the three
steps specified above, for example, an all melt PTT co-polymer may
be produced by omitting the solid state polymerization step, where
the pre-polycondensation step and the melt polycondensation step
produce a melt co-polymer having a intrinsic viscosity of at least
0.7 dl/g, or at least 0.8 dl/g, or at least 0.9 dl/g.
[0049] The phosphorous containing compound of formula (V) where
R.sub.6 and R.sub.7 are both hydrogen atoms may be produced by
reacting equimolar amounts of
9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, shown as
formula (VI),
##STR00011##
with itaconic acid, shown as formula (VII),
##STR00012##
at a temperature of from 120.degree. C. to 200.degree. C. or from
140.degree. C. to 180.degree. C. for a period effective to convert
at least a majority, or at least 75%, or at least 85%, or at least
90% of the reactants to the phosphorous compound of formula (V)
where R.sub.6 and R.sub.7 are hydrogen atoms, which may be a period
of at least 15 minutes, or at least 30 minutes, or at least 60
minutes, or at least 90 minutes. In an embodiment, the preparation
of the phosphorous compound of formula (V) may be conducted under
an inert atmosphere, for example under a nitrogen atmosphere. Where
R.sub.6 and/or R.sub.7 of the phosphorous compound of formula (V)
are an alkyl hydrocarbon group having from 1 to 5 carbons, the
phosphorous compound of formula (V) having R.sub.6 and R.sub.7
hydrogen atoms may be reacted with an alkyl alcohol to produce the
desired phosphorous compound, where the molar ratio of the alkyl
alcohol to the phosphorous compound may range from 0.5:1 to 2.5:1,
or from 1:1 to 2:1. Where R.sub.6 and/or R.sub.7 of the phosphorous
compound of formula (V) are an alkyl alcohol group having 1 to 5
carbon atoms and having one or more alcohol substituents, the
phosphorous compound of formula (V) having R.sub.6 and R.sub.7
hydrogen atoms may be reacted with an alkyl diol or polyol to
produce the desired phosphorous compound, where the molar ratio of
the alkyl diol or polyol to the phosphorous compound may range from
0.5:1 to 2.5:1, or from 1:1 to 2:1. The phosphorous compound having
R.sub.6 and R.sub.7 hydrogen atoms and the alkyl alcohol, diol, or
polyol may be reacted at a temperature of from 75.degree. C. to
200.degree. C., or from 100.degree. C. to 150.degree. C. for a
period of time effective to replace the R.sub.6 and/or R.sub.7
hydrogen atom with the alkyl group, or alkyl alcohol, diol, or
polyol group. In an alternative embodiment, the alkyl alcohol,
diol, or polyol may be added to the reaction mixture of the
9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and itaconic
acid in an amount from equimolar to two times the respective molar
amounts of each of the other reactants.
[0050] In an embodiment of the process, minor amounts of other
compounds may be included in the co-polymerization step that may be
incorporated into the PTT co-polymer product to be used to form the
fiber. For example, compounds such as ethylene glycol, 1,4
butanediol, 1,4-butenediol, 1,4-cyclohexanedimethanol, oxalic acid,
succinic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid,
5-sodiumsulfoisophthalic acid, isophthalic acid, and/or adipic acid
may be included in the co-polymerization step. Such compounds may
be included in amounts that they comprise, in combination with any
such compounds utilized in the esterification step, at most 25 mol
%, or at most 15 mol %, or at most 10 mol %, or at most 5 mol % of
the final PTT co-polymer composition to be spun into fiber.
[0051] The relative amounts of the 1,3-propanediol and terephthalic
acid components used to form the trimethylene terephthalate
containing material in the esterification step and the phosphorous
containing compound of formula (V) in the co-polymerization
reaction step are selected so that trimethylene terephthalate in
the esterification product may be present in the mixture in an
amount of at least 50 mol %, or at least 70 mol %, or at least 90
mol %, or at least 95 mol %, or at least 99 mol % of the total
moles of reactants in the copolymerization step, and the
phosphorous containing compound may be present in the
co-polymerization reaction mixture in an amount greater than 0 mol
% up to 50 mol % of the total moles of reactants in the
copolymerization step, or up to 30 mol %, or up to 10 mol %, or up
to 5 mol %, or up to 1 mol % of the total moles of reactants in the
copolymerization step. In an embodiment, trimethylene terephthalate
may be present in the mixture for co-polymerization an amount of
from 50 mol % to 99.9 mol %, or from 70 mol % to 99 mol % of the
total moles of reactants in the copolymerization step and the
phosphorous containing compound may be present in the mixture in an
amount of from greater than 0 mol % to 50 mol %, or from 0.1 mol %
to 30 mol %, or from 0.5 mol % to 10 mol % of the total moles of
reactants in the copolymerization step. Alternatively, trimethylene
terephthalate may be present in the mixture for copolymerization in
an amount of at least 20 wt. %, or at least 25 wt. %, or at least
30 wt. % up to 99.9 wt. %, or up to 99.5 wt. %, or up to 99 wt. %
of the total weight of the reactants, and the phosphorous compound
of formula (V) may be present in the mixture in an amount of at
least 0.1 wt. %, or at least 0.3 wt. %, or at least 1 wt. %, or at
least 2 wt %, up to 80 wt. %, or up to 75 wt. %, or up to 50 wt. %
of the total weight of the reactants.
[0052] In an embodiment, it may be preferable to maximize the
poly(trimethylene terephthalate) character of the co-polymer by
maximizing the trimethylene terephthalate monomer of formula (I)
content and minimizing the phosphorous containing component of
formula (II) content in the co-polymer. This may be useful to
provide a polymer having characteristics similar to a
poly(trimethylene terephthalate) homopolymer yet having improved
flame retardance relative to a PTT homopolymer. In this embodiment,
the minimum amount of the phosphorous containing compound of
formula (V) required to provide a desired degree of flame
retardancy is included in the co-polymerization step. For example,
at most 5 mol %, or at most 4 mol %, or at most 3 mol %, or at most
2 mol %, or from 0.25 mol % to 3 mol %, or from 0.5 mol % to 2 mol
% of the phosphorous containing compound of formula (V), relative
to the total moles of reactants, may be included in the mixture for
co-polymerization to provide a PTT co-polymer having flame
retardancy with a minimal amount of the phosphorous containing
component of formula (II) monomer. Alternatively, at most 5 wt. %,
or at most 4 wt. %, or at most 3 wt. %, or from 0.5 wt. % to 4 wt.
%, or from 1 wt. % to 3 wt. % of the phosphorous containing
compound of formula (V), based on the total weight of the
reactants, may be included in the mixture for co-polymerization to
provide a PTT co-polymer having flame retardancy with a minimal
amount of the phosphorous containing component monomer.
[0053] The co-polymerization may comprise an optional
pre-polycondensation step which is useful to obtain a high
intrinsic viscosity PTT melt co-polymer, particularly in the
absence of subsequent a solid state polymerization step. In the
pre-polycondensation step, the trimethylene terephthalate
containing material from the esterification step and the
phosphorous containing compound of formula (V) may be mixed and
reacted where the reaction pressure may be reduced to less than 20
kPa (200 mbar), or less than 10 kPa (100 mbar), or from 0.2 kPa to
20 kPa (2 mbar to 200 mbar), or from 0.5 kPa to 10 kPa (5 mbar to
100 mbar) and the temperature may be from 230.degree. C. to
280.degree. C., or from 240.degree. C. to 275.degree. C., or from
250.degree. C. to 270.degree. C. The pre-polycondensation step of
the co-polymerization may be carried out at two or more vacuum
stages, where each stage may have a successively lower pressure.
For example, a two-stage pre-polycondensation may be effected in
which the phosphorous containing compound of formula (V) and the
trimethylene terephthalate containing material from the
esterification step are mixed at an initial pressure of from 5 kPa
to 20 kPa (50 mbar to 200 mbar) and then mixed at a second pressure
of from 0.2 kPa to 2 kPa (2 mbar to 20 mbar) while being held at a
temperature of from 230.degree. C. to 280.degree. C., preferably
from 250.degree. C. to 270.degree. C. The pre-polycondensation step
may be conducted until the pre-polycondensation reaction product
has the desired intrinsic viscosity, which may be for at least 10
minutes, or at least 25 minutes, or at least 30 minutes, and up to
4 hours, or up to 3 hours, or up to 2 hours, or from 10 minutes to
4 hours, or from 25 minutes to 3 hours, or from 30 minutes to 2
hours.
[0054] The pre-polycondensation step of the co-polymerization may
be carried out in the presence of a pre-polycondensation catalyst.
The pre-polycondensation catalyst is preferably a titanium or
zirconium catalyst selected from the titanium and zirconium
catalysts discussed above in relation to the esterification step
due to the high activity of these metals. The pre-polycondensation
catalyst may be provided to the pre-polycondensation reaction mass
in an amount effective to catalyze the reaction, and may be
provided in an amount in the range of 5 to 250 ppm (metal), or in
the range of 10 ppm to 100 ppm (metal), based on the weight of the
final co-polymer. In an embodiment, at least a portion or all of
the pre-polycondensation catalyst may be the catalyst used in the
esterification reaction and included in the pre-polycondensation
reaction in the esterification product mixture.
[0055] The co-polymerization includes a polycondensation step which
may produce a PTT melt co-polymer having an intrinsic viscosity of
at least 0.4 dl/g or at least 0.7 dl/g, or at least 0.8 dl/g, or at
least 0.9 dl/g. In the polycondensation step, the
pre-polycondensation step product, or alternatively the
trimethylene terephthalate containing material from the
esterification step and the phosphorous containing compound of
formula (V), may be mixed and reacted where the reaction pressure
may be reduced to 0.02 kPa to 0.25 kPa (0.2 mbar to 2.5 mbar) and
the temperature may be from 240.degree. C. to 275.degree. C., or
from 250.degree. C. to 270.degree. C. The polycondensation step may
be carried out for a period of time effective to provide a PTT melt
co-polymer having the desired intrinsic viscosity, which is at
least 0.4 dl/g where a subsequent solid state polymerization step
is effected or at least 0.7 dl/g in an all melt process without a
subsequent solid state polymerization step. In general, the
polycondensation step may require from 1 to 6 hours, with shorter
reaction times preferred to minimize the formation of color
bodies.
[0056] The polycondensation step of the co-polymerization includes
a polycondensation catalyst, preferably a titanium or zirconium
compound, such as those discussed above in relation to the
esterification step because of the high activity of these metals. A
preferred polycondensation catalyst is titanium butoxide. The
polycondensation catalyst may be provided to the polycondensation
reaction mass in an amount effective to catalyze the reaction, and
may be provided in an amount in the range of 5 to 250 ppm (metal),
or in the range of 10 ppm to 100 ppm (metal), based on the weight
of the final co-polymer. In an embodiment, at least a portion or
all of the polycondensation catalyst may be the catalyst used in
the pre-polycondensation reaction and/or the esterification
reaction and included in the polycondensation reaction in the
pre-polycondensation product mixture and/or the esterification
product mixture.
[0057] The polycondensation step is most suitably carried out in a
high surface area generation reactor capable of large vapor mass
transfer, such as a cage-type, basket, perforated disk, disk ring,
or twin screw reactor. Optimum results are achievable in the
process from the use of a cage-type reactor or a disk ring reactor,
which promote the continuous formation of large film surfaces in
the reaction product and facilitate evaporation of excess
1,3-propanediol and polymerization by-products.
[0058] The polycondensation step may optionally include the
addition to the reaction mixture of stabilizers, coloring agents,
fillers, and other additives for polymer property modification.
Specific additives include coloring agents such as cobalt acetate
or organic dyes; stabilizers such as hindered phenols; branching
agents such as polyfunctional carboxylic acids, polyfunctional acid
anhydrides, and polyfunctional alcohols; and particulate fillers
including delustering agents such as titanium dioxide, fibrous
materials such as glass fiber, asbestos fiber, carbon fiber, silica
fiber, fibrous woolastonite, silica-alumina fiber, zirconia fiber,
potassium titanate fiber, metal fibers, and organic fibers with
melting points above 300.degree. C., and particulate or amorphous
materials such as carbon black, white carbon, silicon carbide,
silica, powder of quartz, glass beads, glass powder, milled fiber,
silicates such as calcium silicate, aluminum silicate, clay, and
diatomites, metal oxides such as iron oxide, zinc oxide, and
alumina, metal carbonates such as calcium carbonate and magnesium
carbonate, metal sulfates such as calcium sulfate and barium
sulfate, and metal powders To limit particulate induced breakage of
the fiber to be spun from the polycondensed PTT co-polymer,
particulate additives, such as fillers, may be included in the
polycondensation step in a limited amount of from 0 wt. % to 5 wt.
% of the PTT co-polymer composition, more preferably from 0 wt. %
to 3 wt. % of the PTT co-polymer composition.
[0059] Optionally, in an "all-melt" process, upon completion of the
polycondensation (i.e. upon achieving the desired intrinsic
viscosity in the polycondensation mixture), the polycondensation
product may be cooled to produce the flame retardant PTT
co-polymer. The polycondensation product may be cooled, solidified,
and pelletized using a strand pelletizer, an underwater pelletizer,
or a drop forming device.
[0060] The co-polymerization may comprise an optional solid state
polymerization step which is useful to obtain a high intrinsic
viscosity PTT co-polymer, particularly in the absence of
pre-polycondensation step. The polycondensation product may be
cooled, solidified, and pelletized using a strand pelletizer, and
underwater pelletizer, or a drop forming device. The resulting PTT
co-polymer pellets may then be fed into a crystallizer/preheater in
which the pellets are rapidly preheated to a solid state reaction
temperature which is between 150.degree. C. and up to 1.degree. C.
below the melting temperature of the PTT co-polymer. The PTT
co-polymer pellets may be pre-heated for a period of time typically
of from 5 to 60 minutes or from 10 to 30 minutes.
[0061] The crystallizer/preheater may be a fluid bed or an agitated
heat exchanger. Suitable types of fluid beds include standard
(stationary) fluid beds, vibrating fluid beds, and pulsating fluid
beds. Multiple heating zones may be used to narrow the residence
time distribution of the PTT co-polymer pellets as well as to
improve energy efficiency. In a single-zone
crystallizer/pre-heater, the temperature of the direct heat
transfer medium (i.e. hot nitrogen or hot air in a fluid bed) or
the heat transfer surface (of an agitated heat exchanger) is at
least as high as the intended solid state reactor temperature. Thus
the PTT co-polymer is exposed to the reaction temperature as soon
as it is charged into the single-zone crystallizer/preheater. In a
multiple-zone crystallizer/preheater, the heat transfer medium or
heat transfer surface temperature of the first zone may be lower or
no lower than the solid state reactor temperature. Thus the PTT
co-polymer may be exposed to the solid state reaction temperature
in the first or later zones of the multiple-zone
crystallizer/preheater.
[0062] The preheated pellets may then be discharged from the
crystallizer/preheater into a solid state reactor. Inside the solid
state reactor, solid state polycondensation takes place as the PTT
co-polymer pellets move downward by gravitational force in contact
with a stream of inert gas, typically nitrogen, which flows
upwardly to sweep away reaction by-products such as
1,3-propanediol, water, allyl alcohol, acrolein, and cyclic dimer.
The nitrogen flow rate may be from 0.11 to 0.45 kg/min per kg of
PTT co-polymer (0.25 to 1.0 pound per pound of PTT co-polymer). The
nitrogen may be heated or unheated before entering the reactor. The
exhaust nitrogen may be purified and recycled after exiting the
reactor.
[0063] The PTT co-polymer pellets may be discharged as solid-stated
product from the bottom of the solid state reactor, after having
acquired the desired intrinsic viscosity. The solid-stated product
may be cooled to below 65.degree. C. in a product cooler, which may
be a fluid bed or an agitated heat exchanger. The solid-stated PTT
co-polymer product may be cooled in an atmosphere of nitrogen or
air.
[0064] In an embodiment in which the co-polymerization includes a
solid-state polymerization step, the esterfication and
copolymerization steps may be conducted so that a
pre-polycondensation step is not required. The esterification step
may be conducted as described above, where the esterification step
is conducted under a super-atmospheric pressure of from 205 kPa to
550 kPa absolute (2.05 bar to 5.5 bar absolute) in the absence of
an esterification catalyst to produce the trimethylene
terephthalate containing material. The co-polymerization may be
conducted utilizing a polycondensation step and a solid-state
polymerization step, where the polycondensation step includes the
addition of from 10 to 400 ppm of a polycondensation catalyst based
on the weight of the co-polymer, as described above, under reaction
conditions for polycondensation as described above, except that the
polycondensate product needs only have an intrinsic viscosity of at
least 0.25 dl/g. The polycondensate PTT co-polymer product may then
be solid-state polymerized as described above to produce a PTT
co-polymer having an intrinsic viscosity sufficient to be spun into
a fiber, e.g. at least 0.7 dl/g. or at least 0.8 dl/g, or at least
0.9 dl/g.
[0065] In a preferred embodiment, the co-polymerization does not
require a solid state polymerization step, and a PTT co-polymer
having an intrinsic viscosity sufficient to be spun into fiber
(e.g. at least 0.7 dl/g, or at least 0.8 dl/g, or at least 0.9
dl/g) may be produced using an all-melt process in which the
esterification, pre-polycondensation step and the polycondensation
step, as described above, are sufficient to produce the PTT
co-polymer with the required intrinsic viscosity.
[0066] In an alternative embodiment, dimethylterephthalate (DMT)
may be substituted for terephthalic acid in the esterification step
(which becomes a transesterification step upon the substitution).
The process of producing a PTT co-polymer using DMT in place of
terephthalic acid in a transesterification step may be performed in
a similar manner as the process utilizing terephthalic acid in the
esterification step as described above, except that DMT is
substituted for terephthalic acid. The transesterification
generates an alcohol, specifically methanol, which is distilled off
as a byproduct under the transesterification reaction
conditions.
[0067] In another embodiment, the flame retardant PTT co-polymer
composition may be produced by forming the phosphorous containing
compound of formula (V) from
9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, itaconic acid,
and, optionally selected alkyl alcohols, alkyl diols, and/or alkyl
polyols as described above, and including the phosphorous
containing compound of formula (V) in the esterification or
transesterification step described above, followed by the
co-polymerization step as described above. Optionally, in this
embodiment, addition of the phosphorous containing compound of
formula (V) may be excluded from the co-polymerization step
provided sufficient amounts of the phosphorous compound are added
in the esterification or transesterification step to provide the
PTT co-polymer composition with sufficient flame retardancy.
Sufficient amounts of the phosphorous compound required in the
process to provide an effective degree of flame retardancy to the
PTT co-polymer composition are described above. The amounts of
1,3-propanediol, a compound selected from the group consisting of
terephthalic acid, dimethylterephthalate, and mixtures thereof, and
the phosphorous containing compound are also selected to provide
the flame retardant PTT co-polymer composition with from 50 mol %
to 99.9 mol % of the trimethylene terephthalate monomer of formula
(I) in the PTT co-polymer.
[0068] In another embodiment,
9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, itaconic acid,
and, optionally selected alkyl alcohols, alkyl diols, and/or alkyl
polyols as described above, may be directly included in the
esterification or transesterification step of 1,3-propanediol and
terephthalic acid or dimethylterephthalate as described above. In
this embodiment, a phosphorous containing compound of formula (V)
need not be added in either the esterification or
transesterification step or in the copolymerization step, however,
optionally, a phosphorous containing compound of formula (V) may be
added in either of these steps. The amounts of 1,3-propandiol and
terephthalic acid or dimethylterephthalate in the esterification
mixture relative to each other are described above in the
description of the esterification step. The
9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and itaconic
acid may be added in equimolar amounts relative to each other in
the esterification reaction. The amounts of
9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and itaconic
acid relative to 1,3-propanediol and terephthalic acid or
dimethylterephthalate in the esterification reaction mixture may be
selected to provide a final PTT co-polymer composition comprising
at least 50 mol %, or at least 70 mol %, or at least 90 mol %, or
at least 95 mol %, or at least 99 mol % trimethylene terephthalate
monomer of formula (I) above.
[0069] In an embodiment of the process of the present invention, a
supplementary polymer may be mixed with the flame retardant PTT
co-polymer to form a flame retardant PTT containing co-polymer
composition to be spun into a fiber. The flame retardant PTT
co-polymer and supplementary polymer may be mixed at a temperature
of from 180.degree. C. to 280.degree. C. where the temperature is
selected so that flame retardant PTT co-polymer and the
supplementary polymer each have a melting point below the selected
temperature. The supplementary polymer may be mixed with the flame
retardant PTT co-polymer in an amount of up to 25 wt. %, or up to
15 wt. %, or up to 10 wt. %, or up to 5 wt. % of the mixture of the
flame retardant PTT co-polymer and supplementary polymer. In one
embodiment, the supplementary polymer is selected from the group
consisting of polyamides, polysulfones, and polyesters. In an
embodiment, the supplementary polymer may be NYLON-6, NYLON-6,6,
poly(ethylene terephthalate), poly(butylene terephthalate),
poly(ethylene naphthalate), poly(trimethylene naphthalate), or
mixtures thereof.
[0070] In an embodiment of the process of the present invention, a
non-fusible flame retardant that does not have a melting point
below 280.degree. C. may be incorporated in the flame retardant PTT
containing co-polymer to be spun into fiber to provide additional
flame retardancy to the fiber, if desired. Such non-fusible flame
retardants may include: polyhalogenated hydrocarbon compounds;
phosphinate metal salts of the formula (III) above that do not melt
or decompose at or below a temperature of 280.degree. C.; other
phosphorous containing compounds that are non-fusible at a
temperature of equal to or below 280.degree. C., including
inorganic phosphorous compounds such as red phosphorous; monomeric
organic phosphorous compounds; orthophosphoric esters or
condensates thereof; phosphoric ester amides; phosphonitrilic
compounds; phosphine oxides (e.g. triphenylphosphine oxides); metal
salts of phosphoric and phosphonic acids; diphosphinic salts; and
nitrogen containing compounds such as benzoguanamine compounds,
ammonium polyphosphate, and melamine compounds such as melamine
borate, melamine oxalate, melamine phosphate, melamine
pyrophosphate, polymeric melamine phosphate, and melamine
cyanurate. In an embodiment of the process of the present
invention, a non-fusible flame retardant may be incorporated in the
flame retardant PTT containing co-polymer composition by heating
the co-polymer composition to a temperature above the melting point
of the co-polymer composition but below 280.degree. C. and mixing
the non-fusible flame retardant in the molten co-polymer.
[0071] If a non-fusible flame retardant is mixed in the flame
retardant PTT containing co-polymer composition, the non-fusible
flame retardant component in the composition is added in a minor
amount such that the non-fusible flame retardant component may
comprise from 0 wt. % to 5 wt. %, or from 0 wt. % to 2.5 wt. %, or
from 0 wt. % to 1 wt. % of the total weight of the flame retardant
PTT containing composition (including any other polymers, fillers,
or modifying agents mixed with the flame retardant PTT co-polymer)
and the non-fusible flame retardant. Further, if a non-fusible
flame retardant is mixed in the flame retardant PTT containing
co-polymer composition, the non-fusible flame retardant component
mixed in the composition may be particulate. The particle size of
the non-fusible flame retardant component in the composition may
range up to a mean particle size of 150 .mu.m. In an embodiment,
the mean particle size of the non-fusible flame retardant component
may be at most 10 .mu.m, or the non-fusible flame retardant may
contain nanoparticles and may have a mean particle size of at most
1 .mu.m.
[0072] In an embodiment of the process of the present invention, a
fusible flame retardant that has a melting point equal to or less
than 280.degree. C. may be incorporated into the flame retardant
PTT containing co-polymer to be spun into fiber to provide
additional flame retardancy to the fiber, if desired. Such fusible
flame retardants are described above. The fusible flame retardant
may be incorporated into the flame retardant PTT co-polymer
composition by heating the fusible flame retardant and the flame
retardant PTT co-polymer, separately or together, to a temperature
above the melting points of the fusible flame retardant and the
flame retardant PTT co-polymer, then mixing the molten fusible
flame retardant and molten flame retardant PTT co-polymer to
disperse the fusible flame retardant in the PTT co-copolymer.
[0073] If a fusible flame retardant is mixed in the flame retardant
PTT co-polymer composition, the fusible flame retardant component
may be added in a minor amount such that the fusible flame
retardant may comprise from 0 wt. % to 5 wt. %, or from 0.1 wt. %
to 2.5 wt. %, or from 0.1 wt. % to 1 wt. % of the total weight of
the flame retardant PTT co-polymer composition (including any other
polymers, fillers, reinforcing agents, modifying agents, and
non-fusible flame retardant components) mixed with the flame
retardant PTT co-polymer) and the fusible flame retardant.
[0074] In an embodiment of the process of the present invention, a
filler may be mixed into the flame retardant PTT containing
co-polymer composition to be spun into a fiber. "Filler" as the
term is used herein is defined as "a particulate or fibrous
material having no flame retardant activity". Examples of filler
materials that may be utilized in the process of the present
invention include fibrous materials such as glass fiber, asbestos
fiber, carbon fiber, silica fiber, fibrous woolastonite,
silica-alumina fiber, zirconia fiber, potassium titanate fiber,
metal fibers, and organic fibers with melting points above
300.degree. C., carbon black, white carbon, silicon carbide,
silica, powder of quartz, glass beads, glass powder, milled fiber,
silicates such as calcium silicate, aluminum silicate, clay, and
diatomites, metal oxides such as iron oxide, titanium oxide, zinc
oxide, and alumina, metal carbonates such as calcium carbonate and
magnesium carbonate, metal sulfates such as calcium sulfate and
barium sulfate, and metal powders. For purposes of delustering the
fiber of the present invention, titanium dioxide is a preferred
filler. In an embodiment of the process of the present invention, a
filler may be incorporated in the flame retardant PTT containing
co-polymer composition by heating the co-polymer composition to a
temperature above the melting point of the co-polymer composition
but below 280.degree. C. and mixing the filler in the molten
co-polymer. Filler may be mixed in the flame retardant PTT
containing composition such that the filler comprises from 0 wt. %
to 5 wt. %, or from 0 wt. % to 2.5 wt. % or from 0.5 wt. % to 1.0
wt. % of the total weight of the flame retardant PTT containing
co-polymer composition (including any other polymers, flame
retardants, or modifying agents mixed with the flame retardant PTT
co-polymer) and the filler.
[0075] In an embodiment of the process of the present invention, a
modifying agent may be mixed into the flame retardant PTT
containing co-polymer composition to be spun into fiber. "Modifying
agent", as the term is used herein, is defined as a material useful
to modify the physical, chemical, color, or electrical
characteristics of the flame retardant PTT co-polymer composition,
excluding filler materials and reinforcing agents, as defined
above. Modifying agents may include conventional antioxidants,
lubricants, dyes and other colorants, UV absorbers, and antistatic
agents. In an embodiment of the process of the present invention, a
modifying agent may be incorporated in the flame retardant PTT
containing co-polymer composition by heating the co-polymer
composition to a temperature above the melting point of the
co-polymer composition but below 280.degree. C. and mixing the
modifying agent in the molten co-polymer. The modifying agent may
be mixed in the flame retardant PTT containing co-polymer
composition such that the modifying agent comprises from 0 wt. % to
25 wt. %, or from 0 wt. % to 10 wt. % or from 1 wt. % to 5 wt. % of
the total weight of the flame retardant PTT containing co-polymer
composition (including any other polymers, flame retardants, or
filler mixed with the flame retardant PTT co-polymer) and the
modifying agent.
[0076] Once formed, the flame retardant PTT co-polymer composition
may be spun into a fiber. To spin the flame retardant PTT
co-polymer into a fiber, the flame retardant PTT co-polymer may be
heated (or maintained) at a temperature of from 240.degree. C. to
280.degree. C. and drawn or extruded through a spinneret die. The
resulting fiber may then be solidified by cooling. A PTT co-polymer
fiber of the present invention has a tenacity of at least 1.5 g/d,
or at least 1.6 g/d, or at least 1.7 g/d.
[0077] In an embodiment of the process of the invention, the flame
retardant PTT co-polymer, including any additional supplemental
polymer, may be spun into a plurality of fibers that may be
combined and formed into a fully oriented yarn, a partially
oriented yarn, or an undrawn yarn useful in textile or carpet
applications. Referring now to FIG. 1, the flame retardant PTT
co-polymer may be melt blended in extruder at a temperature of from
180.degree. C. to 280.degree. C., preferably from 240.degree. C. to
280.degree. C., where the temperature is selected to be above the
melting point of the flame retardant PTT co-polymer. The molten PTT
co-polymer may then be passed through a spinneret 1 located at the
extruder outlet into a plurality of melt spun continuous
fibers/filaments 2 (as used herein a "filament" is a fiber of
extreme length, and is intended to be encompassed within the
definition of a fiber). The die holes in the spinneret 1 may have a
size and shape selected to provide desired characteristics to a
yarn 3 formed of a plurality of the filaments 2. Multiple
spinnerets (not shown) may be coupled to the extruder to enable
multiple yarns to be spun simultaneously from the molten flame
retardant PTT co-polymer.
[0078] The filaments 2 may be rapidly cooled and converged into a
multifilament yarn 3. The filaments 2 may be cooled by contacting
the filaments 2 with cold air, preferably by blowing cold air over
the filaments 2. In one embodiment, the filaments 2 may pass
through a quench air box or cylinder 4 surrounding the filaments
which defines a cold air zone. The cold air may be directed inward
from the interior surface of the quench air box or cylinder 4 to
cool the filaments 2.
[0079] The multi-filament yarn 3 may be passed through a spin
finish applicator 5, shown in FIG. 1 as an oiling roll, to apply a
finishing agent on the yarn 3. The finishing agent is preferably an
oil agent containing a fatty acid ester and/or mineral oil, or a
polyether.
[0080] The multi-filament flame retardant PTT yarn 3 may then be
processed into a fully drawn yarn, a partially oriented yarn, or an
undrawn yarn.
[0081] If the yarn 3 is to be a fully oriented yarn, the yarn 3 may
be drawn in a one or two-stage drawing process over feed 6 and
drawing rolls 7 and 8 prior to being taken up by a take-up
mechanism 9, where the feed 6 and drawing rolls 7 and 8 may include
at least one heated roll and the relative speeds of the feed 6 and
drawing rolls 7 and 8 and take-up mechanism 9 may be set to produce
a fully oriented yarn. For example, a fully drawn yarn may be
produced by drawing the yarn 3 at a first draw ratio of from 1.01
to 2, and the temperatures of the feed roller 6 and draw rollers 7
and 8 are controlled so the feed roller 6 is operated at a
temperature of less than 100.degree. C. and the draw rollers 7 and
8 are operated at temperatures of greater than the temperature of
the feed roller 6 and within the range of 50.degree. C. to
150.degree. C. The first draw ratio may be controlled by
controlling the speeds of the feed roller 6 relative to the draw
roller 7, for example, the feed roller 6 may rotate at a speed of
1000 m/min and the draw roller 7 may have a speed of 1050 m/min.
The yarn is subsequently drawn at a second draw ratio of at least
2.2 times that of the first draw ratio where the draw roller 8 is
heated to a temperature greater than the draw roller 7 and within
the range of from 100.degree. C. to 200.degree. C. The second draw
ratio may be controlled by controlling the speeds of the draw
roller 8 relative to the draw roller 7, for example, the draw
roller 8 may have a speed of 3000 m/min and the draw roller 7 may
have a speed of 1050 m/min. The drawn yarn may subsequently be
wound with the take-up mechanism 9. Denier control rolls 10 and an
optional relax roller 11 may be used to facilitate the yarn
spinning process. The drawn yarn may be textured prior to or after
winding in accordance with conventional yarn texturing
processes.
[0082] If the yarn 3 is to be a partially oriented yarn, the yarn 3
may be either drawn in a one or two stage process over feed 6 and
drawing rolls 7 and 8 prior to being taken up by a take-up
mechanism 9, or the yarn may be directly taken-up by the take-up
mechanism 9. If the partially oriented yarn is produced by drawing
prior to being taken up by a take-up mechanism, the draw ratio is
less than that used to produce a fully oriented yarn, as described
above, resulting in only partial longitudinal orientation of the
polymer molecules. For example, the yarn 3 may be heated above the
glass transition temperature of the yarn, e.g. at least 45.degree.
C. or at least 60.degree. C., and drawn at a draw ratio of 0.7 to
1.3 in a single stage draw process where the feed roll 6 is
operated at a speed of from 1800 to 3500 m/min and the draw rolls 7
and 8 are operated at the same speed of from 1250 m/min to 4550
m/min, where the relative speed of the draw rolls 7 and 8 to the
feed roll 6 determines the draw ratio. If the partially oriented
yarn is produced by being directly taken up by the take-up
mechanism 9, the take-up mechanism 9 is operated at a speed
effective to induce partial orientation in the yarn. For example,
the take-up mechanism 9 may operate at a speed of 3500 to 4500
m/min or at a speed of from 2000 to 2600 m/min to induce partial
orientation in the yarn while winding the yarn. The partially
oriented yarn may be wound onto a yarn package, and may be
subsequently textured.
[0083] If the yarn 3 is to be an undrawn yarn, the yarn may be
directly taken up by the take-up mechanism 9 at a speed that does
not induce longitudinal orientation of the polymer molecules in the
yarn fiber. For example, the take-up mechanism 9 may operate at a
speed of from 500 m/min to 1500 m/min, or at a speed of from 800
m/min to 1200 m/min, to produce an undrawn yarn. The undrawn yarn
may be subsequently stored in a tow can, textured, drawn, and cut
into staple fibers.
[0084] The textured fully oriented yarn, textured partially
oriented yarn, and textured undrawn yarn may be utilized to produce
textiles or carpets in accordance with known conventional
techniques for forming textiles or carpets from fully oriented,
partially oriented, or undrawn yarns.
[0085] In another embodiment, as shown in FIG. 2, extruded
filaments of the flame retardant PTT co-polymer may be formed into
bulk continuous filaments particularly useful for forming carpets.
Molten PTT polymer may be passed through a spinneret 13 into a
plurality of continuous filaments 14, at a temperature of from
180.degree. C. to 280.degree. C., preferably from 240.degree. C. to
280.degree. C., where the temperature is selected so the
temperature is above the melting point of the flame retardant PTT
co-polymer. The filaments 14 may be rapidly cooled, preferably by
contact with cold air, and converged into a multifilament yarn 15.
The multifilament yarn 15 may be contacted with a spin finish
applicator 16 to apply a finishing agent on the yarn 15. The
finishing agent is preferably an oil agent containing a fatty acid
ester and/or mineral oil, or a polyether.
[0086] The multifilament yarn 15 may be fed to a first drawing
stage by control rolls 17 and 18. The first drawing stage is
defined by feed roll 19 and a draw roll 20. Between rolls 19 and
20, yarn 21 may drawn at a relatively low draw ratio, within the
range of 1.01 to 2 and preferably within the range of 1.01 to 1.35,
where the draw ratio is controlled by selecting the speed of the
rolls 19 and 20. The temperature of the feed roll 19 is kept low,
where preferably the feed roll 19 is unheated, but at most the
temperature of the feed roll 19 is from 30.degree. C. to 80.degree.
C. The draw roll 20 may be heated to a temperature of from
50.degree. C. to 150.degree. C., preferably about 90.degree. C. to
140.degree. C., to facilitate drawing the yarn 21 without breaking
the yarn.
[0087] The drawn yarn 21 may be passed to a second drawing stage
defined by draw rolls 20 and 22. The second stage draw may be
carried out at a relatively high draw ratio with respect to the
first stage draw ratio, generally at least 2.2 times that of the
first stage draw ratio, preferably at a draw ratio within the range
of 2.2 to 3.4 times of that of the first stage. Draw roll 22 may be
maintained at a temperature in the range of 100 to 200.degree. C.
In general, the three rollers 18, 19, and 22 will be sequentially
higher in temperature.
[0088] Drawn yarn 23 may be passed to heated rolls 24 and 25 to
preheat the drawn yarn 23 prior to texturing. The heated drawn yarn
26 may then be texturized by passing the yarn 26 through a
texturing air jet 27 for bulk enhancement of the yarn 26, and then
to a jet cooling drum 28. The bulk textured yarn 29 may then be
passed through tension controls 30, 31, and 32 and through idler 33
to an optional entangler 34 for yarn entanglement. Entangled yarn
35 may be advanced by idler 36 to an optional spin finish
applicator 37 and then is wound onto winder 38. The bulk continuous
filament yarn can then be processed by twisting, texturing, and
heat-setting as desired and tufted into carpet according to
conventional methods.
[0089] In another aspect, the present invention is directed to a
material comprising a plurality of fibers wherein at least 5% of
the fibers are comprised of a flame retardant PTT co-polymer
comprising from 50 mol % to 99.9 mol % of a trimethylene
terephthalte component of formula (I) and from 0.1 mol % to 50 mol
% of a phosphorous containing component of formula (II), as
described above. Such PTT containing co-polymer fibers and
processes for producing them are described above, and may include
additives such as filler, particularly a delusterant, and
supplementary polymers as described above.
[0090] In an embodiment, the material is a carpet. Preferably the
carpet contains at least 50%, or at least 75%, or at least 90%, of
the flame retardant PTT co-polymer fibers. The carpet may be
prepared with the flame retardant PTT co-polymer fibers in
accordance with conventional methods for producing carpets from
synthetic polymer fibers. In an embodiment, the flame retardant PTT
co-polymer fiber used to produce the carpet is a bulk continuous
filament fiber. In another embodiment, the flame retardant PTT
co-polymer fiber used to produce the carpet is a staple fiber
having a length of from 0.5 cm to 15 cm (0.2 in. to 6 in.).
[0091] The carpet of the present invention is a PTT co-polymer
fiber based carpet that is more surface flame resistant than
conventional PTT homopolymer fiber based carpets. The carpet of the
present invention may have sufficient flame resistance to pass a
small-scale ignition test, in particular the "pill test" as
described in 16 C.F.R. .sctn.1630 (.sctn.1630.1-1630.4) (Jan. 1,
2006 Edition) or a comparable test with at least a 85% pass rate,
or at least a 90% pass rate. Specifically, the carpet of the
present invention has a flame resistance such that the probability
that a methanamine tablet ignited on the carpet in a pill test will
char the carpet a distance of at most 7.62 cm (3 in.) from the
tablet is at least 85% or at least 90%.
[0092] The "pill test" as provided in 16 C.F.R. .sctn.1630 (Jan. 1,
2006 Edition) or a comparable test, for purposes of the present
invention, includes the following steps and criteria. A sample of
carpet that includes a circular area having a diameter greater than
20.32 cm (8 in.), more preferably having a diameter of
22.86.+-.0.64 cm (9.+-.1/4 in.) is provided. For purposes of the
present invention the sample may be any shape, e.g. square or
circular, but the sample must include a circular area having a
diameter of at least 20.32 cm--the C.F.R. test requires a square
sample having 22.86.+-.0.64 cm sides. The sample may be washed and
dried 10 times using a wash temperature of 60.degree..+-.3.degree.
C. and a tumble dry exhaust temperature of 66.+-.5.degree. C.
(washing and drying is required in the CFR test, but is not
necessary for a test in accordance with the present invention). The
sample is cleaned until it is free of loose ends and any material
that may have worked into the pile during handling, preferably with
a vacuum cleaner. The sample is placed in a drying oven in a manner
to permit free circulation of air at 105.degree. C. around the
sample for 2 hours, and then is placed in a dessicator with the
carpet traffic surface up until cooled to room temperature, but no
less than 1 hour. The sample is then removed from the dessicator
and brushed with a gloved hand to raise the pile of the sample. The
sample is placed horizontally flat in a test chamber and a metal
plate flattening frame having 20.32 cm (8 in.) diameter hole in its
center is centered and placed on top of the sample (preferably the
metal plate is a 22.86 cm.times.22.86 cm (9 in..times.9 in.) steel
plate with an 20.32 cm diameter hole therein). A methenamine tablet
weighing approximately 0.149 gram is then placed on the sample in
the center of the 20.32 cm hole in the flattening frame. The tablet
is ignited by touching a lighted match or an equivalent lighting
source to the top of the tablet. The test is continued until either
the last vestige of flame or glow disappears or the flaming or
smoldering has approached to within 2.54 cm (1 in.) of the edge of
the hole in the flattening frame at any point. When all combustion
has ceased the shortest distance between the edge of the hole in
the flattening frame and the charred area is measured and recorded.
A sample that passes the test is a sample in which the charred area
is more than 2.54 cm (1 in.) from the edge of the hole in the
flattening frame at any point (is charred less than or equal to
7.62 cm (3 in.) from the location of the pill).
[0093] The carpet of the present invention may also possess
sufficient flame resistance to meet Class I or Class II categories
of the flooring radiant panel test of the American Association of
Testing and Materials ASTM-E-648, incorporated herein by reference.
A sample meeting the Class I category has an average minimum
radiant flux of 0.45 watts per square centimeter, and a sample
meeting the Class II category has an average minimum radiant flux
of 0.22 watts per square centimeter. The flooring radiant panel
test ASTM-E-648 includes the following steps. A 100.times.20 cm (39
in.times.8 in.) carpet sample is horizontally mounted on the floor
of a test chamber having an air/gas-fired radiant energy panel
mounted above the specimen. The air/gas fired radiant energy panel
is positioned to generate a maximum of approximately 1.1 watts per
square centimeter of radiant energy immediately under the panel and
a minimum of approximately 0.1 watts per square centimeter of
radiant energy at the far end of the sample remote from the panel.
A gas-fired pilot burner is used to initiate the flaming of the
sample. The test is continued until the sample ceases to burn. The
distance from the sample burns is measured and recorded. The
radiant heat energy exposure at the point the sample
"self-extinguished" is noted and is reported as the sample's
critical radiant flux--which is the minimum energy needed to
sustain flame propagation.
[0094] In another embodiment, the material is a textile. Preferably
the textile contains at least 5%, or at least 10%, or at least 25%,
or at least 50%, or at least 75%, or at least 90% of the flame
retardant PTT co-polymer fibers. The textile may be prepared with
the flame retardant PTT co-polymer fibers in accordance with
conventional methods for producing textile from synthetic polymer
fibers. In an embodiment, the flame retardant PTT co-polymer fiber
used to produce the textile is a fully oriented yarn or a partially
oriented yarn. In an embodiment, the flame retardant PTT co-polymer
fiber used to produce the textile is a staple fiber.
Example 1
[0095] A fiber composition of the present invention was made in
accordance with the process of the present invention. Terephthalic
acid and 1,3-propanediol were mixed to form a paste, where the
molar ratio of terephthalic acid to 1,3-propanediol was 1:1.25. 20
ppm cobalt acetate and 270 ppm Irganox 1076 were added to the
terephthalic acid and 1,3-propanediol mixture. The paste was then
gradually charged to an esterifier reactor over a period of 60
minutes, where the mass temperature in the esterifier reactor was
maintained at a temperature of 250.degree. C. and the reaction was
conducted under a nitrogen pressure of 0.2 MPa. The esterification
reaction was conducted until 80% of the terephthalic acid was
consumed, a period of 207 minutes, then the esterification product
was transferred to a pre-polycondensation reactor. The
esterification product was initially treated in the
pre-polycondensation reactor at a temperature of 250.degree. C. and
a pressure of 0.15 MPa for a period of 62 minutes. 60 ppm of a
titanium catalyst and 3 wt. % of a mixture of the phosphorous
compound shown below and ethylene glycol, where the ethylene glycol
formed 33 wt. % of the mixture, was then added to the reaction
mixture.
##STR00013##
The pre-polycondensation reactor was then evacuated to a pressure
of 2 kPa over a period of 25 minutes. After achieving vacuum
pressure below 5 kPa the mass temperature in the reactor was
increased to 265.degree. C. in two steps. After the 25 minute
pressure drop in the pre-polycondensation reactor, the reaction
mass was transferred to a polymerization reactor. In the
polymerization reactor, the reaction pressure was decreased to
below 1 kPa and the mass temperature of the reaction mass was
initially increased to 268.degree. C. and then maintained at
264.degree. C. for the duration of the polymerization process.
Polymerization was continued until the co-polymer had an intrinsic
viscosity of 0.74 dl/g, a period of 84 minutes. The co-polymer was
then cooled and casted for solid state polymerization. The solid
co-polymer was then solid state polymerized in a tumbler drier at a
temperature of 205.degree. C. for 7 hours to produce a final
co-polymer product. Properties of the final co-polymer product are
provided in Table 1.
TABLE-US-00001 TABLE 1 Glass Cold % Transition Crystallizaton
Melting Hunter dipropylene Temp. Temp Temp Intrinsic Color Hunter
Hunter glycol (T.sub.g) (T.sub.cc) (T.sub.m) Viscosity L* Color a
Color b ether 45.4.degree. C. 74.degree. C. 224.6.degree. C. 0.95
dl/g 80.5 -4.2 11.4 1.2
[0096] The final co-polymer product was heated to melt the
co-polymer, and then was spun into fiber. The co-polymer was heated
by feeding the co-polymer through an extruder having six heating
zones, where the temperatures of the respective heating zones
ranged from 235.degree. C. to 251.degree. C., where the final
heating zone had a temperature of 251.degree. C. Upon passing
through the extruder the molten co-polymer had a temperature of
260.degree. C. The extruded molten co-polymer was then passed
through a spinning pump operating at 16.8 rpm and extruded through
a spinneret having a capillary size of 0.285.times.0.95 and 68 Y
shaped die holes to form 68 filaments. The filaments were cooled
and combined to form a PTT co-polymer yarn. A Lurol 8666 spin
finish was applied to the PTT co-polymer yarn, and the yarn was
loaded onto a pretension godet roll operating at 1100 m/min. The
PTT co-polymer yarn was then passed to a first draw roll operating
at a speed of 1130 m/min and having temperature of 55.degree. C.,
and was drawn between the first draw roll and a second draw roll
operating at a speed of 3000 m/min at a temperature of 135.degree.
C. The draw ratio on the PTT co-polymer yarn was 2.7. The drawn PTT
co-polymer yarn was then textured with hot air from an airheater
having a temperature of 170.degree. C. The textured PTT co-polymer
yarn was then cooled on a cooling drum operating at 30 rpm and was
drawn up by a third draw roll operating at a speed of 2488 m/min at
ambient temperature. The PTT co-polymer yarn was then wound up on a
winder operating at 2465 m/min to provide a bulk continuous
filament PTT co-polymer yarn. Properties of the PTT co-polymer yarn
are shown in Table 2.
TABLE-US-00002 TABLE 2 Maximum Tenacity elongation Elongation to
Denier (g/d) (%) Break (%) 1515 1.79 60 45
Example 2
[0097] For comparative purposes, a fiber and yarn were prepared
from a poly(trimethylene terephthalate) homopolymer. A
poly(trimethylene terephthalate) polymer was prepared by
esterifying 1,3-propanediol and terephthalic acid under the
conditions set forth in Example 1, except no phosphorous containing
compound was added during the pre-polycondensation step.
The final PTT polymer product was heated to melt the polymer, and
then was spun into fiber. The PTT polymer was heated by feeding the
polymer through an extruder having six heating zones, where the
temperatures of the respective heating zones ranged from
235.degree. C. to 250.degree. C., where the final heating zone had
a temperature of 250.degree. C. Upon passing through the extruder
the molten PTT polymer had a temperature of 255.degree. C. The
extruded molten PTT polymer was then passed through a spinning pump
operating at 16.8 rpm and extruded through a spinneret having a
capillary size of 0.285.times.0.95 and 68 Y shaped die holes to
form 68 filaments. The filaments were cooled and combined to form a
PTT yarn. A Lurol 8666 spin finish was applied to the PTT yarn, and
the PTT yarn was loaded onto a pretension godet roll operating at
1000 m/min. The PTT yarn was then passed to a first draw roll
operating at a speed of 1030 m/min and having temperature of
55.degree. C., and was drawn between the first draw roll and a
second draw roll operating at a speed of 3000 m/min at a
temperature of 144.degree. C. The draw ratio on the PTT yarn was
2.9. The drawn PTT yarn was then textured with hot air from an
airheater having a temperature of 175.degree. C. The textured PTT
yarn was then cooled on a cooling drum operating at 40 rpm and was
drawn up by a third draw roll operating at a speed of 2519 m/min at
ambient temperature. The PTT yarn was then wound up on a winder
operating at 2505 m/min to provide a bulk continuous filament PTT
yarn. Properties of the PTT yarn are shown in Table 3.
TABLE-US-00003 TABLE 3 Maximum Tenacity elongation Elongation to
Denier (g/d) (%) Break (%) 1515 1.85 62 45
[0098] It may be seen by comparing the tenacity of the PTT
co-polymer yarn from Table 2 and the tenacity of the PTT yarn from
Table 3 that the tenacity of the PTT co-polymer yarn is only
slightly lower than the tenacity of the PTT yarn.
Example 3
[0099] A carpet in accordance with the present invention was made
from the PTT co-polymer yarn produced in Example 1, and a carpet
for comparative purposes was made from the PTT polymer yarn
produced in Example 2. The carpets formed from the yarn of Example
1 and Example 2 contained no other fibers or yarns. The yarns were
twisted at 4.75 twists-per-inch and Superba heat-set textured at
138.degree. C. (280.degree. F.). Each yarn was then back wound on
144 packages, and then was creeled and tufted as a 0.57 m (2 ft.)
wide band in 28.8 cm (12 inch) wide broadloom carpet on a 5/32
gauge cutpile machine at 25 opsy. Filler yarn was used for the edge
bands on either side. Each resulting carpet was then beck-dyed in a
dark red color in a pressure beck at atmospheric pressure and
finished with a 600 filler load latex (no ATH). A pill test was
conducted 16 times on samples from the carpets. The results are
shown in Table 4 below.
TABLE-US-00004 TABLE 4 Pill Test Pill Test Sample (Pass/Total) (%
pass) PTT co- 14/16 87.5 polymer, 38 oz. latex weight (Example 1)
PTT polymer, 6/16 37.5 38 oz. latex weight (Example 2)
[0100] Table 4 shows that the carpets having the PTT co-polymer
fibers exhibited reduced flammability relative to carpets having
PTT polymer fibers with no phosphorous containing co-polymer, as
shown by the pill test.
* * * * *