U.S. patent application number 15/268050 was filed with the patent office on 2017-01-05 for phosphorus-containing polymer, article, and processes for producing the same.
The applicant listed for this patent is Milliken & Company. Invention is credited to Warren W. Gerhardt, Stephen D. Lucas, Daniel T. McBride, Rajib Mondal, Jason M. Spruell, Petr Valenta.
Application Number | 20170002150 15/268050 |
Document ID | / |
Family ID | 51985621 |
Filed Date | 2017-01-05 |
United States Patent
Application |
20170002150 |
Kind Code |
A1 |
Gerhardt; Warren W. ; et
al. |
January 5, 2017 |
PHOSPHORUS-CONTAINING POLYMER, ARTICLE, AND PROCESSES FOR PRODUCING
THE SAME
Abstract
A phosphorus-containing polymer comprises a plurality of
phosphorus atoms, wherein about 75% or more of the phosphorus atoms
in the phosphorus-containing polymer are present in phosphine oxide
moieties. An article comprises a textile material having at least
one surface and a phosphorus-containing polymer disposed on a least
a portion of the surface, wherein the phosphorus-containing polymer
comprises a plurality of phosphorus atoms, and wherein about 75% or
more of the phosphorus atoms in the phosphorus-containing polymer
are present in phosphine oxide moieties.
Inventors: |
Gerhardt; Warren W.;
(Spartanburg, SC) ; Spruell; Jason M.;
(Spartanburg, SC) ; McBride; Daniel T.; (Chesnee,
SC) ; Valenta; Petr; (Greer, SC) ; Mondal;
Rajib; (Greer, SC) ; Lucas; Stephen D.;
(Boiling Springs, SC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Milliken & Company |
Spartanburg |
SC |
US |
|
|
Family ID: |
51985621 |
Appl. No.: |
15/268050 |
Filed: |
September 16, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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14292144 |
May 30, 2014 |
9453112 |
|
|
15268050 |
|
|
|
|
61831131 |
Jun 4, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
D03D 13/00 20130101;
D03D 1/00 20130101; C09K 21/14 20130101; D03D 25/00 20130101; C09K
21/00 20130101; C09K 3/00 20130101; D06M 13/285 20130101; D06M
2200/30 20130101; Y10T 442/277 20150401; Y10T 442/20 20150401; D03D
15/00 20130101; B05D 3/02 20130101; D06M 15/431 20130101; C09D 5/18
20130101; C09D 185/02 20130101; C08G 79/04 20130101; B05D 3/10
20130101; D10B 2201/00 20130101 |
International
Class: |
C08G 79/04 20060101
C08G079/04; C09D 185/02 20060101 C09D185/02; C09D 5/18 20060101
C09D005/18 |
Claims
1. A phosphorus-containing polymer comprising a plurality of
phosphorus atoms, wherein about 75% or more of the phosphorus atoms
in the phosphorus-containing polymer are present in phosphine oxide
moieties conforming to a structure selected from the group
consisting of Formula (X), Formula (XI), and Formula (XII)
##STR00011## wherein, in each structure, R.sub.1 is independently
selected from the group consisting of hydrogen, C.sub.1-C.sub.3
alkyl, C.sub.1-C.sub.3 haloalkyl, C.sub.2-C.sub.3 alkenyl, and
C.sub.2-C.sub.3 haloalkenyl; T.sub.1 and T.sub.2 are independently
selected from the group consisting of a hydroxy group and univalent
moieties comprising at least one nitrogen atom; and L is a
polyvalent linking group comprising at least one nitrogen atom.
2. The phosphorus-containing polymer of claim 1, wherein about 80%
or more of the phosphorus atoms in the phosphorus-containing
polymer are present in phosphine oxide moieties conforming to the
structure of Formula (X).
3. The phosphorus-containing polymer of claim 2, wherein about 85%
or more of the phosphorus atoms in the phosphorus-containing
polymer are present in phosphine oxide moieties conforming to the
structure of Formula (X).
4. The phosphorus-containing polymer of claim 1, wherein the
remaining phosphorus atoms in the phosphorus-containing polymer are
present in moieties selected from the group consisting of phosphine
moieties and phosphonium moieties.
5. The phosphorus-containing polymer of claim 1, wherein R.sub.1 is
hydrogen.
6. The phosphorus-containing polymer of claim 1, wherein L is a
polyvalent linking group produced by a reaction with a compound
selected from the group consisting of ammonia, urea, alkylene urea
compounds, melamine, guanidine, guanidine derivatives,
dicyandiamide, and mixtures thereof.
7. A process for producing a phosphorus-containing polymer, the
process comprising the steps of: (a) providing a phosphonium
compound comprising at least one phosphonium moiety, the
phosphonium moiety conforming to the structure of Formula (I)
##STR00012## wherein R.sub.1 is selected from the group consisting
of hydrogen, C.sub.1-C.sub.3 alkyl, C.sub.1-C.sub.3 haloalkyl,
C.sub.2-C.sub.3 alkenyl, and C.sub.2-C.sub.3 haloalkenyl; (b)
providing a nitrogen-containing cross-linking compound, the
nitrogen-containing cross-linking compound comprising two or more
nitrogen-hydrogen bonds; (c) reacting the phosphorus-containing
compound and the nitrogen-containing cross-linking compound in a
condensation reaction to produce a first intermediate polymer; (d)
exposing the first intermediate polymer to a Bronsted base under
conditions sufficient to convert at least a portion of the
phosphonium moieties to phosphine moieties thereby producing a
second intermediate polymer; (e) oxidizing the second intermediate
polymer by exposing the second intermediate polymer to a suitable
oxidizing agent under conditions sufficient to oxidize at least a
portion of the phosphorus atoms in the polymer to a pentavalent
state thereby producing a phosphorus-containing polymer; and (f)
exposing the phosphorus-containing intermediate polymer to a
Bronsted base to neutralize at least a portion of acid generated by
the preceding oxidation step.
8. The process of claim 7, wherein about 75% or more of the
phosphorus atoms in the phosphorus-containing polymer are present
in phosphine oxide moieties conforming to a structure selected from
the group consisting of Formula (X), Formula (XI), and Formula
(XII) ##STR00013## wherein, in each structure, R.sub.1 is
independently selected from the group consisting of hydrogen,
C.sub.1-C.sub.3 alkyl, C.sub.1-C.sub.3 haloalkyl, C.sub.2-C.sub.3
alkenyl, and C.sub.2-C.sub.3 haloalkenyl; T.sub.1 and T.sub.2 are
independently selected from the group consisting of a hydroxy group
and univalent moieties comprising at least one nitrogen atom; and L
is a polyvalent linking group comprising at least one nitrogen
atom.
9. The process of claim 8, wherein about 80% or more of the
phosphorus atoms in the phosphorus-containing polymer are present
in phosphine oxide moieties conforming to a structure selected from
the group consisting of Formula (X), Formula (XI), and Formula
(XII).
10. The process of claim 9, wherein about 85% or more of the
phosphorus atoms in the polymer are present in phosphine oxide
moieties conforming to a structure selected from the group
consisting of Formula (X), Formula (XI), and Formula (XII).
11. The process of claim 7, wherein the remaining phosphorus atoms
in the phosphorus-containing polymer are present in moieties
selected from the group consisting of phosphine moieties and
phosphonium moieties.
12. The process of claim 7, wherein R.sub.1 is hydrogen.
13. The process of claim 7, wherein the nitrogen-containing
cross-linking compound is selected from the group consisting of
ammonia, urea, alkylene urea compounds, melamine, guanidine,
guanidine derivatives, dicyandiamide, and mixtures thereof
14. An article comprising a textile material having at least one
surface and a phosphorus-containing polymer disposed on a least a
portion of the surface, wherein the phosphorus-containing polymer
comprises a plurality of phosphorus atoms, and wherein about 75% or
more of the phosphorus atoms in the phosphorus-containing polymer
are present in phosphine oxide moieties conforming to a structure
selected from the group consisting of Formula (X), Formula (XI),
and Formula (XII) ##STR00014## wherein, in each structure, R.sub.1
is independently selected from the group consisting of hydrogen,
C.sub.1-C.sub.3 alkyl, C.sub.1-C.sub.3 haloalkyl, C.sub.2-C.sub.3
alkenyl, and C.sub.2-C.sub.3 haloalkenyl; T.sub.1 and T.sub.2 are
independently selected from the group consisting of a hydroxy group
and univalent moieties comprising at least one nitrogen atom; and L
is a polyvalent linking group comprising at least one nitrogen
atom.
15. The article of claim 14, wherein the textile material is a
fabric selected from the group consisting of woven fabrics and knit
fabrics.
16. The article of claim 14, wherein the textile material comprises
cellulosic fibers.
17. The article of claim 14, wherein about 80% or more of the
phosphorus atoms in the phosphorus-containing polymer are present
in phosphine oxide moieties conforming to a structure selected from
the group consisting of Formula (X), Formula (XI), and Formula
(XII).
18. The article of claim 17, wherein about 85% or more of the
phosphorus atoms in the phosphorus-containing polymer are present
in phosphine oxide moieties conforming to a structure selected from
the group consisting of Formula (X), Formula (XI), and Formula
(XII).
19. The article of claim 14, wherein R.sub.1 is hydrogen.
20. The article of claim 14, wherein L is a polyvalent linking
group produced by a reaction with a compound selected from the
group consisting of ammonia, urea, alkylene urea compounds,
melamine, guanidine, guanidine derivatives, dicyandiamide, and
mixtures thereof
21. The article of claim 14, wherein the remaining phosphorus atoms
in the phosphorus-containing polymer are present in moieties
selected from the group consisting of phosphine moieties and
phosphonium moieties.
22. A process for producing an article, the process comprising the
steps of: (a) providing a textile material having at least one
surface; (b) providing a phosphonium compound comprising at least
one phosphonium moiety, the phosphonium moiety conforming to the
structure of Formula (I) ##STR00015## wherein R.sub.1 is selected
from the group consisting of hydrogen, C.sub.1-C.sub.3 alkyl,
C.sub.1-C.sub.3 haloalkyl, C.sub.2-C.sub.3 alkenyl, and
C.sub.2-C.sub.3 haloalkenyl; (c) providing a nitrogen-containing
cross-linking compound, the nitrogen-containing cross-linking
compound comprising two or more nitrogen-hydrogen bonds; (d)
applying the phosphorus-containing compound and the
nitrogen-containing compound to at least a portion of the surface
of the textile material; (e) reacting the phosphorus-containing
compound and the nitrogen-containing cross-linking compound in a
condensation reaction to produce a first intermediate polymer on
the surface of the textile material, the first intermediate polymer
comprising a plurality of phosphorus atoms, at least a portion of
the phosphorus atoms being present in phosphonium moieties; (f)
exposing the textile material to a Bronsted base under conditions
sufficient to convert at least a portion of the phosphonium
moieties in the first intermediate polymer to phosphine moieties
thereby producing a second intermediate polymer on the surface of
the textile material; (g) oxidizing the second intermediate polymer
on the surface of the textile material by exposing the textile
material to a suitable oxidizing agent under conditions sufficient
to oxidize at least a portion of the phosphorus atoms in the
polymer to a pentavalent state thereby producing a
phosphorus-containing polymer on the surface of the textile
material; and (h) exposing the textile material to a Bronsted base
to neutralize at least a portion of acid generated by the preceding
oxidation step.
23. The process of claim 22, wherein the textile material is a
fabric selected from the group consisting of woven fabrics and knit
fabrics.
24. The process of claim 22, wherein the textile material comprises
cellulosic fibers.
25. The process of claim 22, wherein about 75% or more of the
phosphorus atoms in the phosphorus-containing polymer are present
in phosphine oxide moieties conforming to a structure selected from
the group consisting of Formula (X), Formula (XI), and Formula
(XII) ##STR00016## wherein, in each structure, R.sub.1 is
independently selected from the group consisting of hydrogen,
C.sub.1-C.sub.3 alkyl, C.sub.1-C.sub.3 haloalkyl, C.sub.2-C.sub.3
alkenyl, and C.sub.2-C.sub.3 haloalkenyl; T.sub.1 and T.sub.2 are
independently selected from the group consisting of a hydroxy group
and univalent moieties comprising at least one nitrogen atom; and L
is a polyvalent linking group comprising at least one nitrogen
atom.
26. The process of claim 25, wherein about 80% or more of the
phosphorus atoms in the phosphorus-containing polymer are present
in phosphine oxide moieties conforming to a structure selected from
the group consisting of Formula (X), Formula (XI), and Formula
(XII).
27. The process of claim 26, wherein about 85% or more of the
phosphorus atoms in the polymer are present in phosphine oxide
moieties conforming to a structure selected from the group
consisting of Formula (X), Formula (XI), and Formula (XII).
28. The process of claim 22, wherein the remaining phosphorus atoms
in the phosphorus-containing polymer are present in moieties
selected from the group consisting of phosphine moieties and
phosphonium moieties.
29. The process of claim 22, wherein R.sub.1 is hydrogen.
30. The process of claim 22, wherein the nitrogen-containing
cross-linking compound is selected from the group consisting of
ammonia, urea, alkylene urea compounds, melamine, guanidine,
guanidine derivatives, dicyandiamide, and mixtures thereof.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims, pursuant to 35 U.S.C.
.sctn.119(e)(1), priority to and the benefit of the filing date of
U.S. Patent Application No. 61/831,131 filed on Jun. 4, 2013 and
U.S. patent application Ser. No. 14/292,144 filed on May 30, 2014
which applications are hereby incorporated by reference in their
entirety.
TECHNICAL FIELD OF THE INVENTION
[0002] This application relates to flame retardant,
phosphorus-containing polymers, processes for producing such
polymers, articles comprising such polymers (e.g., textile
materials treated with such polymers), and processes for producing
such articles.
BACKGROUND
[0003] Flame retardant, phosphorus-containing polymers are
well-known in the industry. These polymers are used to impart a
degree of flame resistance to cellulose-containing fabrics, such as
cotton fabrics. The polymers typically are produced by padding a
tetrahydroxymethyl phosphonium compound and a suitable
cross-linking agent onto the fabric and reacting the two to form
the polymer. The polymers produced by this reaction are known to
release formaldehyde overtime, which can be problematic for a
variety of reasons. The industry has attempted to develop means to
solve this formaldehyde generation problem, but these means seldom
provide a long term solution. Indeed, many of the solutions lose
their efficacy after the treated fabric is washed only a couple of
times and the polymer on the fabric then begins to release
formaldehyde.
[0004] A need therefore remains for improved flame retardant,
phosphorus-containing polymers that generate reduced amounts of
formaldehyde. A need also remains for processes for producing such
polymers and articles treated with such polymers. The invention
described in this application aims to satisfy such need.
BRIEF SUMMARY OF THE INVENTION
[0005] In a first embodiment, the invention provides a
phosphorus-containing polymer comprising a plurality of phosphorus
atoms, wherein about 75% or more of the phosphorus atoms in the
phosphorus-containing polymer are present in phosphine oxide
moieties conforming to a structure selected from the group
consisting of Formula (X), Formula (XI), and Formula (XII)
##STR00001##
wherein, in each structure, R.sub.1 is independently selected from
the group consisting of hydrogen, C.sub.1-C.sub.3 alkyl,
C.sub.1-C.sub.3 haloalkyl, C.sub.2-C.sub.3 alkenyl, and
C.sub.2-C.sub.3 haloalkenyl; T.sub.1 and T.sub.2 are independently
selected from the group consisting of a hydroxy group and univalent
moieties comprising at least one nitrogen atom; and L is a
polyvalent linking group comprising at least one nitrogen atom.
[0006] In a second embodiment, the invention provides a process for
producing a phosphorus-containing polymer, the process comprising
the steps of:
[0007] (a) providing a phosphonium compound comprising at least one
phosphonium moiety, the phosphonium moiety conforming to the
structure of Formula (I)
##STR00002##
wherein R.sub.1 is selected from the group consisting of hydrogen,
C.sub.1-C.sub.3 alkyl, C.sub.1-C.sub.3 haloalkyl, C.sub.2-C.sub.3
alkenyl, and C.sub.2-C.sub.3 haloalkenyl;
[0008] (b) providing a nitrogen-containing cross-linking compound,
the nitrogen-containing cross-linking compound comprising two or
more nitrogen-hydrogen bonds;
[0009] (c) reacting the phosphorus-containing compound and the
nitrogen-containing cross-linking compound in a condensation
reaction to produce a first intermediate polymer, the first
intermediate polymer comprising a plurality of phosphorus atoms, at
least a portion of the phosphorus atoms being present in
phosphonium moieties;
[0010] (d) exposing the first intermediate polymer to a Bronsted
base under conditions sufficient to convert at least a portion of
the phosphonium moieties to phosphine moieties thereby producing a
second intermediate polymer; and
[0011] (e) oxidizing the second intermediate polymer by exposing
the second intermediate polymer to a suitable oxidizing agent under
conditions sufficient to oxidize at least a portion of the
phosphorus atoms in the polymer to a pentavalent state thereby
producing a phosphorus-containing polymer.
[0012] In a third embodiment, the invention provides an article
comprising a textile material having at least one surface and a
phosphorus-containing polymer disposed on a least a portion of the
surface, wherein the phosphorus-containing polymer comprises a
plurality of phosphorus atoms, and wherein about 75% or more of the
phosphorus atoms in the phosphorus-containing polymer are present
in phosphine oxide moieties conforming to a structure selected from
the group consisting of Formula (X), Formula (XI), and Formula
(XII)
##STR00003##
wherein, in each structure, R.sub.1 is independently selected from
the group consisting of hydrogen, C.sub.1-C.sub.3 alkyl,
C.sub.1-C.sub.3 haloalkyl, C.sub.2-C.sub.3 alkenyl, and
C.sub.2-C.sub.3 haloalkenyl; T.sub.1 and T.sub.2 are independently
selected from the group consisting of a hydroxy group and univalent
moieties comprising at least one nitrogen atom; and L is a
polyvalent linking group comprising at least one nitrogen atom.
[0013] In a fourth embodiment, the invention provides a process for
producing an article, the process comprising the steps of:
[0014] (a) providing a textile material having at least one
surface;
[0015] (b) providing a phosphonium compound comprising at least one
phosphonium moiety, the phosphonium moiety conforming to the
structure of Formula (I)
##STR00004##
[0016] wherein R.sub.1 is selected from the group consisting of
hydrogen, C.sub.1-C.sub.3 alkyl, C.sub.1-C.sub.3 haloalkyl,
C.sub.2-C.sub.3 alkenyl, and C.sub.2-C.sub.3 haloalkenyl;
[0017] (c) providing a nitrogen-containing cross-linking compound,
the nitrogen-containing cross-linking compound comprising two or
more nitrogen-hydrogen bonds;
[0018] (d) applying the phosphorus-containing compound and the
nitrogen-containing compound to at least a portion of the surface
of the textile material;
[0019] (e) reacting the phosphorus-containing compound and the
nitrogen-containing cross-linking compound in a condensation
reaction to produce a first intermediate polymer on the surface of
the textile material, the first intermediate polymer comprising a
plurality of phosphorus atoms, at least a portion of the phosphorus
atoms being present in phosphonium moieties;
[0020] (f) exposing the textile material to a Bronsted base under
conditions sufficient to convert at least a portion of the
phosphonium moieties in the first intermediate polymer to phosphine
moieties thereby producing a second intermediate polymer on the
surface of the textile material; and
[0021] (g) oxidizing the second intermediate polymer on the surface
of the textile material by exposing the textile material to a
suitable oxidizing agent under conditions sufficient to oxidize at
least a portion of the phosphorus atoms in the polymer to a
pentavalent state thereby producing a phosphorus-containing polymer
on the surface of the textile material.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is the .sup.31P nuclear magnetic resonance (NMR)
spectrum for the flame retardant, phosphorus-containing polymer
from a commercially-available flame resistant textile article.
[0023] FIG. 1A shows the .sup.31P NMR spectrum from FIG. 1 with a
"deconvoluted" spectrum superimposed over the original spectrum.
FIG. 1A also includes a table providing the calculated area for
each of the "deconvoluted" peaks.
[0024] FIG. 2 is the .sup.31P NMR spectrum for the flame retardant,
phosphorus-containing polymer from another commercially-available
flame resistant textile article.
[0025] FIG. 2A shows the .sup.31P NMR spectrum from FIG. 2 with a
"deconvoluted" spectrum superimposed over the original spectrum.
FIG. 2A also includes a table providing the calculated area for
each of the "deconvoluted" peaks.
[0026] FIG. 3 shows the .sup.31P NMR spectrum for the flame
retardant, phosphorus-containing polymer from another
commercially-available flame resistant textile article. FIG. 3 also
shows a "deconvoluted" spectrum superimposed over the original
spectrum. FIG. 3 also includes a table providing the calculated
area for each of the "deconvoluted" peaks.
[0027] FIG. 4 is the .sup.31P NMR spectrum for a flame retardant,
phosphorus-containing polymer according to the invention that has
been applied to a textile material.
[0028] FIG. 4A shows the .sup.31P NMR spectrum from FIG. 4 with a
"deconvoluted" spectrum superimposed over the original spectrum.
FIG. 4A also includes a table providing the calculated area for the
"deconvoluted" peaks.
DETAILED DESCRIPTION OF THE INVENTION
[0029] In a first embodiment, the invention provides a
phosphorus-containing polymer. The polymer comprises a plurality of
phosphorus atoms. Most of these phosphorus atoms are present in the
"backbone" of the polymer, meaning that the phosphorus atoms are
joined together by intervening linking moieties. This is in
contrast to some phosphorus-containing polymers in which the
phosphorus atoms are contained in pendant groups that are attached
to the polymer backbone.
[0030] The phosphorus atoms are present in the polymer in
phosphorus-containing moieties. As noted above, these
phosphorus-containing moieties are bonded to adjacent
phosphorus-containing moieties, thereby forming the backbone of the
polymer chain. In these moieties, the phosphorus atoms can be
present in different oxidation states, which yield different
phosphorus-containing moieties. In particular, it is believed that
within the polymer the phosphorus atoms can exist in one of two
oxidation states: phosphorus (III) or phosphorus (V). The
phosphorus atoms in the phosphorus (III) oxidation state can be
present in phosphine moieties or phosphonium moieties; and the
phosphorus atoms in the phosphorus (V) oxidation state are present
in phosphine oxide moieties.
[0031] Preferably, at least a portion of the phosphorus atoms are
present in the phosphorus-containing polymer in phosphine oxide
moieties conforming to a structure selected from the group
consisting of Formula (X), Formula (XI), and Formula (XII)
##STR00005##
In the structures of Formula (X), Formula (XI), and Formula (XII),
R.sub.1 can be any suitable group, such as an alkyl group, a
haloalkyl group, an alkenyl group, or a haloalkenyl group; T.sub.1
and T.sub.2 are independently selected from the group consisting of
a hydroxy group and univalent moieties comprising at least one
nitrogen atom; and L is a polyvalent linking group comprising at
least one nitrogen atom. As used herein, the term "polyvalent" in
reference to the linking group L means that the linking group has
two or more bonds to adjacent moieties. Thus, even though the
structures set forth in the application only show two bonds
emanating from the linking group, it is possible for the linking
group to be bonded to more than two adjacent moieties.
[0032] In a preferred embodiment, R.sub.1 is independently selected
from the group consisting of hydrogen, C.sub.1-C.sub.3 alkyl,
C.sub.1-C.sub.3 haloalkyl, C.sub.2-C.sub.3 alkenyl, and
C.sub.2-C.sub.3 haloalkenyl. In the structure of Formula (X),
Formula (XI), Formula (XII), and the structures that follow, the
partial bonds (i.e., the bonds truncated by the wavy line)
represent bonds to adjacent phosphorus-containing moieties, such as
moieties conforming to the structures of Formula (X), (XI), and
(XII) as well as the other phosphorus-containing moieties described
below. In a preferred embodiment, R.sub.1 is hydrogen.
[0033] In another preferred embodiment, T.sub.1 and T.sub.2 are
independently selected from the group consisting of a hydroxy group
and univalent moieties comprising at least one nitrogen atom that
are produced by a reaction with a compound selected from the group
consisting of urea, an alkylene urea, a guanidine (i.e., guanidine,
a salt thereof, or a guanidine derivative), melamine, a melamine
derivative, guanamine, guanyl urea, glycoluril, ammonia, an
ammonia-formaldehyde adduct, an ammonia-acetaldehyde adduct, an
ammonia-butyraldehyde adduct, an ammonia-chloral adduct,
glucosamine, a polyamine (e.g., polyethyleneimine, polyvinylamine,
polyetherimine, polyethyleneamine, polyacrylamide, chitosan,
aminopolysaccharides), glycidyl ethers, isocyanates, blocked
isocyanates and combinations thereof. Given the manner in which the
polymer is produced (which is described in detail below), the
structure of the T can vary from phosphine oxide moiety to
phosphine oxide moiety. This can occur if only a portion of the
terminal hydroxy groups on the phosphonium compound react with the
cross-linking compound, which would yield a polymer containing a
mixture of terminal hydroxy groups and terminal nitrogen moieties.
This can also occur if a mixture of different cross-linking
compounds is used to produce the polymer. Preferably, T.sub.1 and
T.sub.2 are independently selected from the group consisting of a
hydroxy group and moieties produced by a reaction with a compound
selected from the group consisting of ammonia, urea, alkylene urea
compounds, melamine, guanidine, guanidine derivatives,
dicyandiamide, and mixtures thereof.
[0034] In another preferred embodiment, each L is a polyvalent
linking group produced by a reaction with a compound selected from
the group consisting of urea, an alkylene urea, a guanidine (i.e.,
guanidine, a salt thereof, or a guanidine derivative), melamine, a
melamine derivative, guanamine, guanyl urea, glycoluril, ammonia,
an ammonia-formaldehyde adduct, an ammonia-acetaldehyde adduct, an
ammonia-butyraldehyde adduct, an ammonia-chloral adduct,
glucosamine, a polyamine (e.g., polyethyleneimine, polyvinylamine,
polyetherimine, polyethyleneamine, polyacrylamide, chitosan,
aminopolysaccharides), glycidyl ethers, isocyanates, blocked
isocyanates and combinations thereof. Given the manner in which the
polymer is produced (which is described in detail below), the
structure of the linking group (L) can vary from phosphine oxide
moiety to phosphine oxide moiety. This can occur if a mixture of
different cross-linking compounds is used to produce the polymer.
Preferably, L is a polyvalent linking group produced by a reaction
with a compound selected from the group consisting of ammonia,
urea, alkylene urea compounds, melamine, guanidine, guanidine
derivatives, dicyandiamide, and mixtures thereof.
[0035] In a preferred embodiment, about 75% or more of the
phosphorus atoms in the phosphorus-containing polymer are present
in phosphine oxide moieties conforming to a structure selected from
the group consisting of Formula (X), Formula (XI), and Formula
(XII). More preferably, about 80% or more of the phosphorus atoms
in the phosphorus-containing polymer are present in phosphine oxide
moieties conforming to a structure selected from the group
consisting of Formula (X), Formula (XI), and Formula (XII). Most
preferably, about 85% or more (e.g., about 90% or more) of the
phosphorus atoms in the phosphorus-containing polymer are present
in phosphine oxide moieties conforming to a structure selected from
the group consisting of Formula (X), Formula (XI), and Formula
(XII).
[0036] The remaining phosphorus atoms in the phosphorus-containing
polymer preferably are present in moieties selected from the group
consisting of phosphine moieties and phosphonium moieties. The
phosphine moieties preferably conform to a structure selected from
the group consisting of Formula (XV), Formula (XVI), and Formula
(XVII)
##STR00006##
In the structures of Formula (XV), Formula (XVI), and Formula
(XVII), R.sub.1 can be any suitable group, such as an alkyl group,
a haloalkyl group, an alkenyl group, or a haloalkenyl group;
T.sub.1 and T.sub.2 are independently selected from the group
consisting of a hydroxy group and univalent moieties comprising at
least one nitrogen atom; and L is a polyvalent linking group
comprising at least one nitrogen atom. In a preferred embodiment,
R.sub.1 is independently selected from the group consisting of
hydrogen, C.sub.1-C.sub.3 alkyl, C.sub.1-C.sub.3 haloalkyl,
C.sub.2-C.sub.3 alkenyl, and C.sub.2-C.sub.3 haloalkenyl. In a
preferred embodiment, R.sub.1 is hydrogen. In another preferred
embodiment, T.sub.1 and T.sub.2 are independently selected from the
group consisting of a hydroxy group and univalent moieties
comprising at least one nitrogen atom that are produced by a
reaction with a compound selected from the group consisting of
urea, an alkylene urea, a guanidine (i.e., guanidine, a salt
thereof, or a guanidine derivative), melamine, a melamine
derivative, guanamine, guanyl urea, glycoluril, ammonia, an
ammonia-formaldehyde adduct, an ammonia-acetaldehyde adduct, an
ammonia-butyraldehyde adduct, an ammonia-chloral adduct,
glucosamine, a polyamine (e.g., polyethyleneimine, polyvinylamine,
polyetherimine, polyethyleneamine, polyacrylamide, chitosan,
aminopolysaccharides), glycidyl ethers, isocyanates, blocked
isocyanates and combinations thereof. As with the structures of
Formula (X), Formula (XI), and Formula (XII), the structure of T
can vary from phosphine moiety to phosphine moiety. Preferably,
T.sub.1 and T.sub.2 are independently selected from the group
consisting of a hydroxy group and moieties produced by a reaction
with a compound selected from the group consisting of ammonia,
urea, alkylene urea compounds, melamine, guanidine, guanidine
derivatives, dicyandiamide, and mixtures thereof. In another
preferred embodiment, each L is a polyvalent linking group produced
by a reaction with a compound selected from the group consisting of
urea, an alkylene urea, a guanidine (i.e., guanidine, a salt
thereof, or a guanidine derivative), melamine, a melamine
derivative, guanamine, guanyl urea, glycoluril, ammonia, an
ammonia-formaldehyde adduct, an ammonia-acetaldehyde adduct, an
ammonia-butyraldehyde adduct, an ammonia-chloral adduct,
glucosamine, a polyamine (e.g., polyethyleneimine, polyvinylamine,
polyetherimine, polyethyleneamine, polyacrylamide, chitosan,
aminopolysaccharides), glycidyl ethers, isocyanates, blocked
isocyanates and combinations thereof. As with the structures of
Formula (X), Formula (XI), and Formula (XII), the structure of the
linking group (L) can vary from phosphine moiety to phosphine
moiety. Preferably, L is a polyvalent linking group produced by a
reaction with a compound selected from the group consisting of
ammonia, urea, alkylene urea compounds, melamine, guanidine,
guanidine derivatives, dicyandiamide, and mixtures thereof.
[0037] The phosphonium moieties preferably conform to a structure
selected from the group consisting of Formula (XX), Formula (XXI),
Formula (XXII), and Formula (XXIII)
##STR00007##
In the structures of Formula (XX), Formula (XXI), Formula (XXII),
and Formula (XXIII), R.sub.1 can be any suitable group, such as an
alkyl group, a haloalkyl group, an alkenyl group, or a haloalkenyl
group; T.sub.1, T.sub.2, and T.sub.3 are independently selected
from the group consisting of a hydroxy group and univalent moieties
comprising at least one nitrogen atom; and L is a polyvalent
linking group comprising at least one nitrogen atom. In a preferred
embodiment, R.sub.1 is independently selected from the group
consisting of hydrogen, C.sub.1-C.sub.3 alkyl, C.sub.1-C.sub.3
haloalkyl, C.sub.2-C.sub.3 alkenyl, and C.sub.2-C.sub.3
haloalkenyl. In a preferred embodiment, R.sub.1 is hydrogen. In
another preferred embodiment, T.sub.1, T.sub.2, and T.sub.3 are
independently selected from the group consisting of a hydroxy group
and univalent moieties comprising at least one nitrogen atom that
are produced by a reaction with a compound selected from the group
consisting of urea, an alkylene urea, a guanidine (i.e., guanidine,
a salt thereof, or a guanidine derivative), melamine, a melamine
derivative, guanamine, guanyl urea, glycoluril, ammonia, an
ammonia-formaldehyde adduct, an ammonia-acetaldehyde adduct, an
ammonia-butyraldehyde adduct, an ammonia-chloral adduct,
glucosamine, a polyamine (e.g., polyethyleneimine, polyvinylamine,
polyetherimine, polyethyleneamine, polyacrylamide, chitosan,
aminopolysaccharides), glycidyl ethers, isocyanates, blocked
isocyanates and combinations thereof. As with the structures of
Formula (X), Formula (XI), and Formula (XII), the structure of T
can vary from phosphonium moiety to phosphonium moiety. Preferably,
T.sub.1, T.sub.2, and T.sub.3 are independently selected from the
group consisting of a hydroxy group and moieties produced by a
reaction with a compound selected from the group consisting of
ammonia, urea, alkylene urea compounds, melamine, guanidine,
guanidine derivatives, dicyandiamide, and mixtures thereof. In
another preferred embodiment, each L is a polyvalent linking group
produced by a reaction with a compound selected from the group
consisting of urea, an alkylene urea, a guanidine (i.e., guanidine,
a salt thereof, or a guanidine derivative), melamine, a melamine
derivative, guanamine, guanyl urea, glycoluril, ammonia, an
ammonia-formaldehyde adduct, an ammonia-acetaldehyde adduct, an
ammonia-butyraldehyde adduct, an ammonia-chloral adduct,
glucosamine, a polyamine (e.g., polyethyleneimine, polyvinylamine,
polyetherimine, polyethyleneamine, polyacrylamide, chitosan,
aminopolysaccharides), glycidyl ethers, isocyanates, blocked
isocyanates and combinations thereof. As with the structures of
Formula (X), Formula (XI), and Formula (XII), the structure of the
linking group (L) can vary from phosphonium moiety to phosphonium
moiety. Preferably, L is a polyvalent linking group produced by a
reaction with a compound selected from the group consisting of
ammonia, urea, alkylene urea compounds, melamine, guanidine,
guanidine derivatives, dicyandiamide, and mixtures thereof.
[0038] The phosphonium moieties conforming to a structure selected
from the group consisting of Formula (XX), Formula (XXI), Formula
(XXII), and Formula (XXIII) can have any suitable counterion.
Suitable counterions include, but are not limited to, halides
(e.g., chloride), sulfate, hydrogen sulfate, phosphate, acetate,
carbonate, bicarbonate, borate, and hydroxide.
[0039] Preferably, about 25% or less of the phosphorus atoms in the
phosphorus-containing polymer are present in phosphine moieties and
phosphonium moieties, such as the moieties of Formulae (XV), (XVI),
(XVII), (XX), (XXI), (XXII), and (XXIII) above. More preferably,
about 20% or less of the phosphorus atoms in the
phosphorus-containing polymer are present in phosphine moieties and
phosphonium moieties, such as the moieties of Formulae (XV), (XVI),
(XVII), (XX), (XXI), (XXII), and (XXIII) above. Most preferably,
about 15% or less (e.g., about 10% or less) of the phosphorus atoms
in the phosphorus-containing polymer are present in phosphine
moieties and phosphonium moieties, such as the moieties of Formulae
(XV), (XVI), (XVII), (XX), (XXI), (XXII), and (XXIII) above.
[0040] The phosphorus-containing polymer preferably comprises a
relatively small amount of phosphorus atoms in phosphine moieties.
In a preferred embodiment, about 5% or less of the phosphorus atoms
in the phosphorus-containing polymer are present in phosphine
moieties, such as the moieties of Formulae (XV), (XVI), and (XVII)
above. More preferably, about 3% or less of the phosphorus atoms in
the phosphorus-containing polymer are present in phosphine
moieties, such as the moieties of Formulae (XV), (XVI), and (XVII)
above. Most preferably, about 1% or less of the phosphorus atoms in
the phosphorus-containing polymer are present in phosphine
moieties, such as the moieties of Formulae (XV), (XVI), and (XVII)
above.
[0041] The amount of phosphorus atoms present in each of the
oxidation states and corresponding moieties can be determined by
any suitable method. Since the amounts and ranges provided above
refer to the amounts of atoms throughout the polymer, the method
used to characterize the phosphorus atoms in the polymer should be
selected so that it can characterize atoms located throughout the
polymer, rather than only those atoms proximate to the surface of
the polymer film. Preferably, the polymer is analyzed using solid
state .sup.31P nuclear magnetic resonance (NMR) using a direct
acquire Bloch decay pulse sequence (direct excitation and detection
on phosphorus run with proton decoupling). In order to increase the
resolution of the NMR spectra, the samples should be spun at 11 kHz
at the magic angle with respect to the direction of the magnetic
field. This magic angle spinning results in spinning sidebands
emanating from the isotropic peak at 11 kHz periods. In the
resulting spectra, phosphorus atoms in different oxidation states
exhibit different chemical shifts. The phosphorus atoms in the
phosphine moieties exhibit an isotropic peak at a chemical shift of
approximately -27 ppm. The phosphorus atoms in the phosphonium
moieties exhibit an isotropic peak at a chemical shift of
approximately 28 ppm with sidebands at approximately -80 ppm and 81
ppm. The phosphorus atoms in the phosphine oxide moieties exhibit
an isotropic peak at a chemical shift of approximately 45 ppm with
sidebands at approximately -65 ppm, -11 ppm, and 153 ppm. The
isotropic peaks and the sideband peaks at these different chemical
shifts can be used to both qualitatively confirm the presence of
phosphorus atoms in a given oxidation state and to quantify the
relative amount of phosphorus atoms in each oxidation state.
[0042] In order to quantify the relative amount of phosphorus atoms
in each oxidation state, the resulting NMR spectra can be analyzed
using global peak deconvolution (line fitting) performed by
suitable analytical software, such as Mnova 6.0 software, with peak
position, width, and Lorentzian/Gaussian character being the
independent variables. In this method, the fitting iterations are
continued until an acceptable fit is achieved. The resulting
"deconvoluted" spectrum then shows a series of separate peaks at
each chemical shift, and the area under these separate peaks (or at
least a portion of the separate peaks) can be used to determine the
relative amount of phosphorus atoms in each oxidation state. FIGS.
1, 2, and 3 show the .sup.31P NMR spectra of three
phosphorus-containing polymers from commercially-available, flame
resistant fabrics. FIGS. 1A, 2A, and 3 also show a "deconvoluted"
spectrum superimposed over the original NMR spectrum. FIGS. 1A, 2A,
and 3 also include a table providing the area of each
"deconvoluted" peak. As noted above, the area of these peaks can be
used to calculate the relative amount of phosphorus atoms in each
oxidation state.
[0043] FIG. 4 shows the .sup.31P NMR spectrum for a representative
phosphorus-containing polymer according to the invention that has
been applied to a textile material. FIG. 4A shows a "deconvoluted"
spectrum superimposed over the original NMR spectrum. As can be
seen from the analysis of the spectrum and table, about 92% or more
of the phosphorus atoms in the polymer are present in phosphine
oxide moieties. In analyzing this spectrum, only the peaks
appearing at chemical shifts of approximately 45 ppm (corresponding
to the phosphine oxide moiety) and 28 ppm (corresponding to the
phosphonium moiety) were used. This is due to the fact that the
polymer contained a very low amount of phosphorus atoms in
phosphonium moieties, and the only peak for the phosphonium
moieties that could be reliably "deconvoluted" from the original
NMR spectrum was the peak at a chemical shift of approximately 28
ppm.
[0044] The phosphorus-containing polymer of the invention is
believed to contain a substantially greater amount of phosphorus
atoms in phosphine oxide moieties than previously-known
phosphorus-containing polymers. As noted above, applicants analyzed
several commercially-available fabrics that have been treated with
similar, known phosphorus-containing polymers. The NMR spectra for
three such commercially-available fabrics are set forth as FIGS.
1-3. These analyses revealed that only about 67-72% of the
phosphorus atoms were present in phosphine oxide moieties. This is
substantially less than the amount of phosphorus atoms in phosphine
oxide moieties contained in the polymer of the invention.
Furthermore, the results for the commercially-available fabrics
were very surprising. The conventional thinking in the industry was
that all or substantially all of the phosphorus atoms in the
polymers would be present in phosphine oxide moieties. Indeed,
those in the industry believed that the conditions used to produce
the phosphorus-containing polymers on these fabrics were sufficient
to oxidize all or substantially all of the phosphorus atoms into
phosphine oxide moieties. However, the NMR analyses described above
clearly show that this is not the case--a relatively large portion
of the phosphorus atoms remain in either phosphine or phosphonium
moieties.
[0045] The observed difference in the amount of phosphorus atoms
present in phosphine oxide moieties is not a trivial matter. For
example, the phosphine oxide moiety is more robust and less
susceptible to degradation than the phosphine and phosphonium
moieties. So, increasing the amount of phosphorus atoms in
phosphine oxide moieties should increase the durability of the
resulting polymer. A more durable polymer will impart better long
term flame resistance to those substrates (e.g., textile materials)
to which it is applied. In particular, Applicants have observed
improved durability of the phosphorus-containing polymer to
industrial washing conditions where the high temperature, high
detergency, and high pH of the wash water can lead to the
hydrolytic degradation of phosphorus-containing polymers.
[0046] In addition to increased durability, a higher content of
phosphine oxide moieties has been observed to improve the thermal
protective performance of the polymer and any substrate (e.g.,
textile material) on which the polymer is disposed. As the
phosphorus-containing polymer of the invention and similar
phosphorus-containing polymers are exposed to high heat, the
phosphorus atoms in the polymer are oxidized to various oxides of
phosphorus, such as phosphoric acid, phosphates, and/or related
species. The resulting oxides of phosphorus aid the formation of a
"char" on the substrate that separates the flame or heat from the
remaining polymer (or the substrate on which the polymer is
disposed) and slows the heat transfer to this unburned fuel. The
slowed heat transfer in turn provides flame resistance and thermal
protection. However, the oxidation of the phosphorus atoms is an
exothermic reaction, and it is believed that the heat released
during this reaction can actually decrease the thermal protective
performance of a polymer. As noted above, the phosphorus-containing
polymer of the invention contains a relatively high amount of
phosphorus atoms in the pentavalent, phosphine oxide state. These
phosphorus atoms, which are already highly oxidized, will undergo
less oxidation and release less heat before they are converted to
the above-described oxides of phosphorus. Conversely, a polymer
containing a relatively large amount of phosphorus atoms in
phosphine moieties and/or phosphonium moieties, such as
conventional polymers produced by known processes, will release a
greater amount of heat as more of the phosphorus atoms in the
polymer undergo oxidation to form the oxides of phosphorus.
[0047] Also, while not wishing to be bound to any particular
theory, Applicants believe that phosphonium moieties in these
phosphorus-containing polymers are largely responsible for the
evolution of formaldehyde that has been observed with prior art
polymers. More specifically, Applicants believe that the
phosphonium moieties are relatively unstable and will over time
degrade to yield a phosphine moiety and generate formaldehyde and
other by-products. For example, the commercially-available fabrics
tested above (i.e., the fabrics used to determine relative amounts
of phosphorus atoms in different phosphorus-containing moieties)
exhibited extractable formaldehyde contents of about 120-300 ppm as
received. By way of contrast, the phosphorus-containing polymer of
the invention, with its increased amount of phosphine oxide
moieties, exhibits a much lower extractable formaldehyde content.
For example, a textile material treated with a
phosphorus-containing polymer according to the invention having
about 86% of its phosphorus atoms in phosphine oxide moieties
exhibited an extractable formaldehyde content of only about 80 ppm.
Another textile material treated with a phosphorus-containing
polymer according to the invention having about 95% of its
phosphorus atoms in phosphine oxide moieties exhibited an
extractable formaldehyde content of only about 18 ppm. These
relatively low formaldehyde contents are desirable and can be
easily remediated to acceptable levels using formaldehyde
scavengers if necessary. The extractable formaldehyde content of
the polymer and/or a substrate to which the polymer is applied can
be measured using any suitable technique. Preferably, the
extractable formaldehyde content is measured in accordance with
International Standard ISO 14184-1 entitled "Textiles-Determination
of formaldehyde."
[0048] The phosphorus-containing polymer can be produced by any
suitable process. However, in another embodiment, the invention
provides a process for producing the phosphorus-containing polymer.
The process generally comprises the steps of: (a) providing a
phosphonium compound comprising at least one phosphonium moiety;
(b) providing a nitrogen-containing cross-linking compound, the
nitrogen-containing cross-linking compound comprising two or more
nitrogen-hydrogen bonds; (c) reacting the phosphorus-containing
compound and the nitrogen-containing cross-linking compound in a
condensation reaction to produce a first intermediate polymer; (d)
exposing the first intermediate polymer to a Bronsted base under
conditions sufficient to convert at least a portion of the
phosphonium moieties to phosphine moieties thereby producing a
second intermediate polymer; (e) oxidizing the second intermediate
polymer by exposing the second intermediate polymer to a suitable
oxidizing agent under conditions sufficient to oxidize at least a
portion of the phosphorus atoms in the polymer to a pentavalent
state thereby producing a phosphorus-containing polymer; and (f)
exposing the phosphorus-containing intermediate polymer to a
Bronsted base to neutralize at least a portion of acid generated by
the preceding oxidation step.
[0049] The phosphonium compound used in the method preferably
comprises a phosphonium moiety conforming to the structure of
Formula (I)
##STR00008##
[0050] In the structure of Formula (I), R.sub.1 is selected from
the group consisting of hydrogen, C.sub.1-C.sub.3 alkyl,
C.sub.1-C.sub.3 haloalkyl, C.sub.2-C.sub.3 alkenyl, and
C.sub.2-C.sub.3 haloalkenyl. In the structure of Formula (I), the
partial bonds (i.e., the bonds truncated by the wavy line)
represent bonds to other groups or moieties. For example, these
other group or moieties can be hydroxyalkyl groups having a similar
structure to those depicted in Formula (I), or they can be moieties
comprised of a linking group bonded to another phosphonium moiety
having a similar structure.
[0051] Thus, in certain embodiments, the phosphonium compound can
be a phosphonium salt conforming to the structure of Formula
(II)
##STR00009##
In the structure of Formula (II), R.sub.1 can be any suitable
group, such as an alkyl group, a haloalkyl group, an alkenyl group,
or a haloalkenyl group. In a preferred embodiment, R.sub.1 is
selected from the group consisting of hydrogen, C.sub.1-C.sub.3
alkyl, C.sub.1-C.sub.3 haloalkyl, C.sub.2-C.sub.3 alkenyl, and
C.sub.2-C.sub.3 haloalkenyl. In another preferred embodiment,
R.sub.1 can be hydrogen. In the structure of Formula (II), X
represents an anion and can be any suitable monatomic or polyatomic
anion. In a preferred embodiment, X can be an anion selected from
the group consisting of halides (e.g., chloride), sulfate, hydrogen
sulfate, phosphate, acetate, carbonate, bicarbonate, borate, and
hydroxide. In another preferred embodiment, X is a sulfate anion.
In the structure of Formula (II), b represents the charge of the
anion X. Therefore, in order to provide a phosphonium compound that
is charge neutral, the number of phosphonium cations present in the
compound is equal to (-b). Examples of such phosphonium compounds
that are suitable for use in the process of the invention include,
but are not limited to, tetrahydroxymethyl phosphonium salts, such
as tetrahydroxymethyl phosphonium chloride, tetrahydroxymethyl
phosphonium sulfate, tetrahydroxymethyl phosphonium acetate,
tetrahydroxymethyl phosphonium carbonate, tetrahydroxymethyl
phosphonium borate, and tetrahydroxymethyl phosphonium
phosphate.
[0052] The phosphonium compound used in the process can also be a
"precondensate," which is a phosphonium compound made by reacting a
phosphonium salt with a suitable cross-linking agent. Phosphonium
salts suitable for use in making such precondensates include, but
are not limited to, the phosphonium salt compound conforming to the
structure of Formula (II) above. Cross-linking agents suitable for
making such precondensates include, but are not limited to, urea,
alkylene urea, a guanidine (i.e., guanidine, a salt thereof, or a
guanidine derivative), guanyl urea, glycoluril, ammonia, an
ammonia-formaldehyde adduct, an ammonia-acetaldehyde adduct, an
ammonia-butyraldehyde adduct, an ammonia-chloral adduct,
glucosamine, a polyamine (e.g., polyethyleneimine, polyvinylamine,
polyetherimine, polyethyleneamine, polyacrylamide, chitosan,
aminopolysaccharides), glycidyl ethers, isocyanates, blocked
isocyanates and combinations thereof. Phosphonium condensates
suitable for use in generating the polymer of the invention are
well known in the art. Examples of such precondensates are
described, for example, in U.S. Pat. No. 7,713,891 (Li et al.);
U.S. Pat. No. 8,012,890 (Li et al.); and U.S. Pat. No. 8,012,891(Li
et al.). The synthesis of such condensates is also described, for
example, in Frank et al. (Textile Research Journal, November 1982,
pages 678-693) and Frank et al. (Textile Research Journal, December
1982, pages 738-750). Some of these precondensates are also
commercially available, for example, as PYROSAN.RTM. CFR from
Emerald Performance Materials.
[0053] In one possible embodiment, the phosphonium compound can be
a precondensate made by reacting a phosphonium salt, such as that
described above, with melamine or a melamine derivative.
Preferably, the melamine compound conforms to the structure of
Formula (III)
##STR00010##
In the structure of Formula (III), R.sub.2, R.sub.3, R.sub.4,
R.sub.5, R.sub.6, and R.sub.7 can be any suitable groups. In a
preferred embodiment, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6,
and R.sub.7 are independently selected from the group consisting of
hydrogen, hydroxymethyl, and alkoxymethyl. Suitable compounds
include, but are not limited to, melamine, methylolated melamines,
and alkoxymethyl melamines (e.g., etherified methylol melamines).
Such a precondensate can be made by reacting the phosphonium salt
with one melamine compound or a mixture of two or more melamine
compounds.
[0054] The reactant mixture used to make the precondensate
described above can contain any suitable amounts of the phosphonium
salt and the melamine compound. The amounts of the phosphonium salt
and the melamine compound in the reactant mixture can be expressed
through a molar ratio of the two components in the reactant
mixture. However, as will be understood by those skilled in the art
(and as illustrated below), it is the phosphonium cation(s) in the
phosphonium salt that participate in the reaction between the
phosphonium salt and the melamine compound. (The phosphonium salt's
counterion is simply there to balance the charge.) Thus, in order
to accurately express the relative amount of each reactive
component present in the reactant mixture, the molar amount of the
phosphonium salt present in the reactant mixture should be
normalized to express the number of reactive phosphonium cations
contributed to the reactant mixture by the phosphonium salt. This
can be simply done by taking the number of moles of the phosphonium
salt present in the reactant mixture and multiplying this value by
the number of phosphonium cations present in a molecule of the
phosphonium salt. For example, if the reactant mixture contains one
mole of a phosphonium salt containing two phosphonium cations per
molecule (e.g., tetrahydroxymethyl phosphonium sulfate), then the
reactant mixture will contain two moles of reactive phosphonium
cations ([1 mole of tetrahydroxymethyl phosphonium
sulfate].times.[2 phosphonium cations per molecule of
tetrahydroxymethyl phosphonium sulfate]=2 moles of phosphonium
cations). If two or more phosphonium salts are present in the
reactant mixture, then this calculation must be separately
performed for each phosphonium compound. The results from each
calculation can then be added to arrive at the total number of
moles of reactive phosphonium cations present in the reactant
mixture. The figure representing the number of moles of phosphonium
cations present in the reactant mixture and the molar amount of the
melamine compound can then be used to express the relative amounts
of the phosphonium salt and the melamine compound in the reactant
mixture (e.g., a molar ratio of phosphonium cations to melamine
compound), as discussed below.
[0055] Preferably, the phosphonium salt and the melamine compound
are present in the reactant mixture in an initial molar ratio of
phosphonium cations to melamine compound of about 50:1 or less,
about 40:1 or less, about 30:1 or less, about 25:1 or less, about
20:1 or less, about 15:1 or less, about 10:1 or less, or about 8:1
or less. The phosphonium salt and the melamine compound preferably
are present in the reactant mixture in an initial molar ratio of
phosphonium cations to melamine compound of about 3:1 or more or
about 6:1 or more. In a preferred embodiment, the phosphonium salt
and the melamine compound are present in the reactant mixture in an
initial molar ratio of phosphonium cations to melamine compound of
about 50:1 to about 3:1. In another preferred embodiment, the
phosphonium salt and the melamine compound are present in the
reactant mixture in an initial molar ratio of phosphonium cations
to melamine compound of about 40:1 to about 3:1, about 30:1 to
about 3:1, about 25:1 to about 3:1, about 20:1 to about 3:1, about
15:1 to about 3:1 (e.g., about 15:1 to about 6:1), about 10:1 to
about 3:1, or about 8:1 to about 3:1 (e.g., about 6:1).
[0056] The reactant mixture used to produce the precondensate of a
phosphonium salt and a melamine compound can contain other
components in addition to the phosphonium salt and the melamine
compound described above. For example, the reactant mixture can
contain other nitrogenous compounds, such as urea, guanazole,
biguanide, or alkylene ureas. While these other nitrogenous
compounds can be present in the reactant mixture, they are
typically present in a relatively small amount as compared to the
amount of the melamine compound present in the reactant mixture.
The reactant mixture can also contain a surfactant, such as an
alkoxylated alcohol, which aids in the dispersion of the melamine
compound. The reactant mixture can also contain one or more pH
buffers, such as acetate salts (e.g., sodium acetate), phosphate
salts (e.g., alkaline metal phosphate salts), tertiary amines, and
amino alcohols.
[0057] The process can utilize one of the above-described
phosphonium compounds, or the process can utilize a mixture of two
or more such phosphonium compounds. For example, the process can
utilize only a phosphonium salt or a precondensate as described
above. Alternatively, the process can utilize a mixture of
different phosphonium salts, a mixture of precondensates, or a
mixture of one or more phosphonium salts and one or more
precondensates.
[0058] The process of the invention utilizes a nitrogen-containing
cross-linking compound to react with the phosphonium compound to
produce an intermediate polymer. The nitrogen-containing
cross-linking compound preferably comprises two or more
nitrogen-hydrogen bonds. In the cross-linking compound, these
hydrogen atoms can be bonded to the same nitrogen atom (such as in
ammonia), or the hydrogen atoms can be bonded to different nitrogen
atoms. Suitable cross-linking compounds include, for example, urea,
alkylene urea, a guanidine (i.e., guanidine, a salt thereof, or a
guanidine derivative), melamine, a melamine derivative, guanamine,
guanyl urea, glycoluril, ammonia, an ammonia-formaldehyde adduct,
an ammonia-acetaldehyde adduct, an ammonia-butyraldehyde adduct, an
ammonia-chloral adduct, glucosamine, a polyamine (e.g.,
polyethyleneimine, polyvinylamine, polyetherimine,
polyethyleneamine, polyacrylamide, chitosan, aminopolysaccharides),
glycidyl ethers, isocyanates, blocked isocyanates and combinations
thereof. Preferably, the nitrogen-containing cross-linking compound
is selected from the group consisting of ammonia, urea, alkylene
urea compounds, melamine, guanidine, guanidine derivatives,
dicyandiamide, and mixtures thereof.
[0059] In the process, the phosphonium compound and the
nitrogen-containing cross-linking compound are reacted in a
condensation reaction to produce a first intermediate polymer. In
this condensation reaction, hydrogen-bearing nitrogen atoms in the
cross-linking compound react with hydroxyalkyl groups on the
phosphonium compound to form a link and eliminate water. The exact
functional group produced by the reaction will vary depending on
the nature of the cross-linking compound used. Further, because the
nitrogen-containing cross-linking compound contains at least two
nitrogen-hydrogen bonds, the cross-linking compound can react with
at least two hydroxyalkyl groups, thereby allowing the polymer
chain to be propagated. In this reaction step, the phosphonium
compound and the nitrogen-containing cross-linking compound can be
reacted in any suitable amount. The amounts of the two components
can be expressed in terms of the initial weight ratio of the two
components. In a preferred embodiment, the phosphonium compound and
the cross-linking compound are present in the treatment composition
in an initial weight ratio of about 1:2 or more, about 1:1 or more,
about 3:2 or more, about 2:1 or more, or about 3:1 or more. In
another preferred embodiment, the phosphonium compound and the
cross-linking compound are present in the treatment composition in
an initial weight ratio of phosphonium compound to cross-linking
compound of about 10:1 or less, about 9:1 or less, about 8:1 or
less, about 7:1 or less, about 6:1 or less, about 5:1 or less,
about 4:1 or less, or about 3:1 or less. Thus, in certain preferred
embodiments, the phosphonium compound and the cross-linking
compound are present in the treatment composition in an initial
weight ratio of phosphonium compound to cross-linking compound of
about 1:2 to about 10:1 (e.g., about 1:2 to about 5:1), about 1:1
to about 10:1 (e.g., about 1:1 to about 8:1, about 1:1 to about
6:1, about 1:1 to about 5:1, or about 1:1 to about 4:1), about 3:2
to about 10:1 (e.g., about 3:2 to about 8:1, about 3:2 to about
4:1), or about 2:1 to about 10:1 (e.g., about 2:1 to about 8:1,
about 2:1 to about 6:1, about 2:1 to about 5:1, about 2:1 to about
4:1, or about 2:1 to about 3:1). As noted above, more than one
nitrogen-containing cross-linking compound can be used. If multiple
nitrogen-containing cross-linking compounds are used, then the
ratios above refer to the total amount of all of the
nitrogen-containing cross-linking compounds.
[0060] In order to accelerate the condensation reaction between the
phosphonium compound and the cross-linking compound, the reactant
mixture can be heated. Such heating is not always necessary to
achieve a satisfactory reaction rate. For example, when ammonia is
used as the cross-linking compound, heating is not required. The
time and elevated temperature used in this step can be any suitable
combination of time and temperature that results in the reaction of
the phosphonium compound and cross-linking compound to the desired
degree. Suitable temperatures and times for this step will vary
depending upon the oven used and the speed with which heat is
transferred to the substrate, but suitable conditions can range
from temperatures of about 149.degree. C. (300.degree. F.) to about
177.degree. C. (350.degree. F.) and times from about 1 minute to
about 3 minutes.
[0061] After the phosphonium compound and the nitrogen-containing
cross-linking compound react to form the first intermediate
polymer, the first intermediate polymer is exposed to a Bronsted
base. While not wishing to be bound to any particular theory, it is
believed that phosphorus atoms in the intermediate polymer exist in
equilibrium between trivalent phosphorus in phosphine moieties and
tetravalent phosphorus in phosphonium moieties. When the first
intermediate polymer is exposed to a Bronsted base, this
equilibrium is shifted and at least a portion of the phosphorus
atoms contained in phosphonium moieties in the polymer are
converted to phosphine moieties. These phosphine moieties are more
easily oxidized to phosphine oxide moieties in the following
step(s). The result is a phosphorus-containing polymer containing a
relatively high amount of phosphorus atoms in phosphine oxide
moieties, higher than had been previously accomplished using known
or conventional techniques for producing these polymers. This step
of exposing the first intermediate polymer to the Bronsted base
prior to oxidation is believed to be unique to the present process.
Conventional processes for producing similar phosphorus-containing
polymers entail the oxidation of an intermediate polymer prior to
exposing the polymer to a Bronsted base. In such conventional
processes, the polymer is not exposed to the oxidizing agent after
it is exposed to the Bronsted base. Therefore, fewer of the
phosphorus atoms are in an oxidation state that can be readily
oxidized to the pentavalent state and, consequently, the polymers
produced by these conventional processes contain fewer phosphorus
atoms in phosphine oxide moieties than the polymers of the present
invention. Applicants discovery of this effect is surprising and
unexpected because the step of exposing the polymer to the Bronsted
base was previously viewed simply as a means to neutralize acid
produced by the oxidation step--no one realized it could convert
phosphorus-containing moieties within the polymer to a state that
is more easily oxidized to the desired pentavalent, phosphine oxide
state.
[0062] The Bronsted base used in this step can be any suitable
base, but strong bases, such as alkalis, are preferred. For
example, sodium hydroxide (soda), potassium hydroxide (potash),
calcium hydroxide (lime), or any combination thereof can be used.
The Bronsted base typically is provided in the form of an aqueous
solution that is applied to the intermediate polymer or in which
the intermediate polymer is submerged. The Bronsted base can be
contained in this solution in any suitable amount, but preferably
the concentration of the base is great enough to yield a solution
having a pH of about 12 or greater (e.g., about 13 or greater, or
about 14). Preferably, the first intermediate polymer is exposed to
the Bronsted base under conditions sufficient to raise the pH of
the first intermediate polymer and/or the medium in which the first
intermediate polymer is contained to about 6 or more.
[0063] Next, the second intermediate polymer (the polymer resulting
from exposing the first intermediate polymer to the Bronsted base)
is exposed to an oxidizing agent in order to oxidize at least a
portion of the phosphorus atoms in the second intermediate polymer
to phosphine oxide moieties, thereby yielding the desired
phosphorus-containing polymer. Suitable oxidizing agents include,
but are not limited to, oxygen (e.g., gaseous oxygen), hydrogen
peroxide, sodium perborate, sodium hypochlorite, percarbonate
(e.g., alkaline metal percarbonates), ozone, peracetic acid, and
mixtures or combinations thereof. Suitable oxidizing agents also
include compounds that are capable of generating hydrogen peroxide
or peroxide species, which compounds can be used alone or in
combination with any of the oxidizing agents listed above. In a
preferred embodiment, the oxidizing agent is selected from the
group consisting of hydrogen peroxide, sodium perborate, or sodium
hypochlorite, and combinations thereof, with hydrogen peroxide
being particularly preferred. The amount of oxidant can vary
depending on the actual materials used, but typically the oxidizing
agent is incorporated in a solution containing about 5% or more,
about 10% or more, about 15% or more, about 20% or more, about 25%
or more, or about 30% or more by weight of the oxidizing agent.
[0064] After the second intermediate polymer is oxidized, the
resulting phosphorus-containing polymer preferably is further
exposed to a Bronsted base. This second exposure to the Bronsted
base can serve two purposes. First, it neutralizes at least a
portion of the acid that is generated by the oxidation step. If
such acid is not neutralized, it can over time degrade the polymer
or a substrate to which the polymer is applied. Second, the second
exposure to the Bronsted base can be used in preparation for a
second oxidation step as described below. In this second scenario,
the exposure to the Bronsted base can convert at least a portion of
any remaining phosphonium moieties into phosphine moieties which
will enable an even greater degree of oxidation of the phosphorus
atoms to the desired pentavalent phosphine oxide state. This
additional step can be performed using the conditions described
above for the initial neutralization step performed on the first
intermediate polymer. Preferably, the polymer is exposed to the
Bronsted base under conditions sufficient to raise the pH of the
polymer and/or the medium in which the polymer is contained to
about 6 or more.
[0065] If the phosphorus-containing polymer is exposed to a
Bronsted base an additional time as described above, the polymer
can be again exposed to an oxidizing agent in order to further
oxidize more of the phosphorus atoms in the polymer to phosphine
oxide moieties. This step can be performed using the conditions
described above for the initial oxidation step.
[0066] If the polymer is subjected to a second oxidation step as
described above, the polymer can again be exposed to a Bronsted
base. This step can be performed using the conditions described
above for the initial neutralization step performed on the first
intermediate polymer. Preferably, the polymer is exposed to the
Bronsted base under conditions sufficient to raise the pH of the
polymer and/or the medium in which the polymer is contained to
about 6 or more.
[0067] The order of the steps in the process can, within certain
parameters, be changed from the specific order mentioned above. For
example, in one embodiment, the first intermediate polymer can
first be oxidized as described above, then exposed to the Bronsted
base, then oxidized again, and finally exposed to the Bronsted base
again. The common parameter for any variation of the process steps
will be that the polymer is exposed to a Bronsted base, then
oxidized, and again exposed to a Bronsted base after the oxidation.
As discussed above, Applicants believe that exposure to a Bronsted
base prior to the oxidation step is needed in order to convert a
greater portion of the phosphorus moieties in the polymer into a
state that can be converted to phosphine oxide moieties in the
oxidation step.
[0068] The conditions used in the process described above
preferably yield a phosphorus-containing polymer in which about 75%
or more of the phosphorus atoms in the polymer are present in
phosphine oxide moieties conforming to a structure selected from
the group consisting of Formula (X), Formula (XI), and Formula
(XII). More preferably, about 80% or more of the phosphorus atoms
in the polymer are present in phosphine oxide moieties conforming
to a structure selected from the group consisting of Formula (X),
Formula (XI), and Formula (XII). Most preferably, about 85% or more
(e.g., about 90% or more) of the phosphorus atoms in the polymer
are present in phosphine oxide moieties conforming to a structure
selected from the group consisting of Formula (X), Formula (XI),
and Formula (XII).
[0069] In each of the neutralization steps described above (i.e.,
steps in which the intermediate polymer is exposed to a Bronsted
base), the solution comprising the Bronsted base can optionally
further comprise a formaldehyde scavenging compound. Any compound
capable of binding formaldehyde can be used, such as sodium
sulfite. While not wishing to be bound to any particular theory,
Applicants believe that the presence of the formaldehyde scavenging
compound leads to the conversion of at least some of the
phosphonium moieties to phosphine moieties, which can then be
oxidized to phosphine oxide moieties as described above. More
specifically, Applicants believe that the phosphonium moieties in
the intermediate polymer react to yield a phosphine moiety and
release formaldehyde and other by-products. However, even under the
highly basic conditions employed in the above-described
neutralization steps, the equilibrium for this reaction heavily
favors the phosphonium moiety. In other words, only a relatively
small quantity of phosphonium moieties will be converted to
phosphine moieties before the reaction equilibrates and the
conversion stops. Applicants believe that by binding the
formaldehyde that is produced by this reaction, the formaldehyde
can be effectively removed from the equilibrium reaction. And, by
consuming one of the products in the equilibrium reaction, the
equilibrium can be disturbed causing more phosphonium moieties to
be converted into phosphine moieties. Then, it is believed there
will be a greater number of phosphine moieties that are available
to be converted into phosphine oxide moieties in subsequent
oxidation steps. The end result will be a polymer containing a
higher percentage of phosphine oxide moieties than would be
achieved using conventional production processes.
[0070] After the above-described neutralization step, the resulting
phosphorus-containing polymer can be rinsed to remove any
impurities and unreacted materials. This rinse can be performed in
any suitable solvent or medium, provided the medium does not
degrade the phosphorus-containing polymer. Typically, the polymer
is rinsed in water (e.g., running water) until the pH of the water
is relatively neutral, such as a pH of about 6 to about 8, or about
7.
[0071] As briefly mentioned above, the phosphorus-containing
polymer according to the invention is believed to be particularly
well suited for use as a treatment to impart flame resistance to
substrates, such as textile materials. As utilized herein, the term
"flame resistant" refers to a material that burns slowly or is
self-extinguishing after removal of an external source of ignition.
The flame resistance of textile materials can be measured by any
suitable test method, such as those described in National Fire
Protection Association (NFPA) 701 entitled "Standard Methods of
Fire Tests for Flame Propagation of Textiles and Films," ASTM D6413
entitled "Standard Test Method for Flame Resistance of Textiles
(vertical test)", NFPA 2112 entitled "Standard on Flame Resistant
Garments for Protection of Industrial Personnel Against Flash
Fire", ASTM F1506 entitled "The Standard Performance Specification
for Flame Resistant Textile Materials for Wearing Apparel for Use
by Electrical Workers Exposed to Momentary Electric Arc and Related
Thermal Hazards", and ASTM F1930 entitled "Standard Test Method for
Evaluation of Flame Resistant Clothing for Protection Against Flash
Fire Simulations Using an Instrumented Manikin."
[0072] Thus, in another embodiment, the invention provides an
article comprising a textile material and a phosphorus-containing
polymer according to the invention. The textile material has at
least one surface, and the phosphorus-containing polymer described
above is on at least a portion of this surface.
Phosphorus-containing polymers suitable for use in this embodiment
of the invention have been described, and each of the
phosphorus-containing polymers described therein can be used in
this article embodiment of the invention.
[0073] The article of the invention can comprise any suitable
amount of the phosphorus-containing polymer. In a preferred
embodiment, the phosphorus-containing polymer is present in the
article in an amount that provides about 0.5% or more (e.g., about
1% or more, about 1.5% or more, about 2% or more, about 2.5% or
more, about 3% or more, about 3.5% or more, about 4% or more, or
about 4.5% or more) of elemental phosphorus based on the weight of
the untreated textile material. In another preferred embodiment,
the phosphorus-containing polymer is present in the article in an
amount that provides about 5% or less (e.g., about 4.5% or less,
about 4% or less, about 3.5% or less, about 3% or less, about 2.5%
or less, about 2% or less, about 1.5% or less, or about 1% or less)
of elemental phosphorus based on the weight of the untreated
textile material. Preferably, the phosphorus-containing polymer is
present in the article in an amount that provides about 1% to about
4%, about 1% to about 3%, or about 1% to about 2.5% of elemental
phosphorus based on the weight of the untreated textile
material.
[0074] The textile material used in this embodiment of the
invention can be any suitable textile material. The textile
material generally comprises a fabric formed from one or more
pluralities or types of yarns. The textile material can be formed
from a single plurality or type of yarn (e.g., the fabric can be
formed solely from yarns comprising a blend of cellulosic fibers
and synthetic fibers, such as polyamide fibers), or the textile
material can be formed from several pluralities or different types
of yarns (e.g., the fabric can be formed from a first plurality of
yarns comprising cellulosic fibers and polyamide fibers and a
second plurality of yarns comprising an inherent flame resistant
fiber).
[0075] The yarns used in making the textile materials of the
invention can be any suitable type of yarn. Preferably, the yarns
are spun yarns. In such embodiments, the spun yarns can be made
from a single type of staple fiber (e.g., spun yarns formed solely
from cellulose fibers or spun yarns formed solely from inherent
flame resistant fibers), or the spun yarns can be made from a blend
of two or more different types of staple fibers (e.g., spun yarns
formed from a blend of cellulose fibers and thermoplastic synthetic
staple fibers, such as polyamide fibers). Such spun yarns can be
formed by any suitable spinning process, such as ring spinning,
air-jet spinning, or open-end spinning. In certain embodiments, the
yarns are spun using a ring spinning process (i.e., the yarns are
ring spun yarns).
[0076] The textile materials of the invention can be of any
suitable construction. In other words, the yarns forming the
textile material can be provided in any suitable patternwise
arrangement producing a fabric. Preferably, the textile materials
are provided in a woven construction, such as a plain weave, basket
weave, twill weave, satin weave, or sateen weave. Suitable plain
weaves include, but are not limited to, ripstop weaves produced by
incorporating, at regular intervals, extra yarns or reinforcement
yarns in the warp, fill, or both the warp and fill of the textile
material during formation. Suitable twill weaves include both
warp-faced and fill-faced twill weaves, such as 2/1, 3/1, 3/2, 4/1,
1/2, 1/3, or 1/4 twill weaves. In certain embodiments of the
invention, such as when the textile material is formed from two or
more pluralities or different types of yarns, the yarns are
disposed in a patternwise arrangement in which one of the yarns is
predominantly disposed on one surface of the textile material. In
other words, one surface of the textile material is predominantly
formed by one yarn type. Suitable patternwise arrangements or
constructions that provide such a textile material include, but are
not limited to, satin weaves, sateen weaves, and twill weaves in
which, on a single surface of the fabric, the fill yarn floats and
the warp yarn floats are of different lengths.
[0077] Preferably, the textile material comprises cellulosic
fibers. As utilized herein, the term "cellulosic fibers" refers to
fibers composed of, or derived from, cellulose. Examples of
suitable cellulosic fibers include cotton, rayon, linen, jute,
hemp, cellulose acetate, and combinations, mixtures, or blends
thereof. Preferably, the cellulosic fibers comprise cotton
fibers.
[0078] In those embodiments of the textile material comprising
cotton fibers, the cotton fibers can be of any suitable variety.
Generally, there are two varieties of cotton fibers that are
readily available for commercial use in North America: the Upland
variety (Gossypium hirsutum) and the Pima variety (Gossypium
barbadense). The cotton fibers used as the cellulosic fibers in the
invention can be cotton fibers of either the Upland variety, the
Pima variety, or a combination, mixture, or blend of the two.
Generally, cotton fibers of the Upland variety, which comprise the
majority of the cotton used in the apparel industry, have lengths
ranging from about 0.875 inches to about 1.3 inches, while the less
common fibers of the Pima variety have lengths ranging from about
1.2 inches to about 1.6 inches. In a preferred embodiment, at least
some of the cotton fibers used in the textile material are of the
Pima variety, which are preferred due to their greater, more
uniform length.
[0079] In those embodiments in which the textile material comprises
cellulosic fibers, the cellulosic fibers can be present in the
yarns making up the textile material in any suitable amount. For
example, in preferred embodiments, the cellulosic fibers can
comprise about 20% or more (e.g., about 30% or more), by weight, of
the fibers present in one of the pluralities or types of yarn used
in making the textile material. In a possibly preferred embodiment,
the cellulosic fibers can comprise about 100%, by weight, of the
fibers used in making the textile material. In certain other
preferred embodiments, the yarn can include non-cellulosic fibers.
In such preferred embodiments, the cellulosic fibers can comprise
about 20% to about 100% (e.g., about 30% to about 90%), by weight,
of the fibers present in one of the pluralities or types of yarn
used in making the textile material. The remainder of the yarn can
be made up of any suitable non-cellulosic fiber or combination of
non-cellulosic fibers, such as the thermoplastic synthetic fibers
and inherent flame resistant fibers discussed below.
[0080] In those embodiments in which the textile material comprises
cellulosic fibers, the cellulosic fibers can be present in the
textile material in any suitable amount. For example, in certain
embodiments, the cellulosic fibers can comprise about 15% or more,
about 20% or more, about 25% or more, about 30% or more, or about
35% or more, by weight, of the fibers present in the textile
material. While the inclusion of cellulosic fibers can improve the
comfort of the textile material (e.g., improve the hand and
moisture absorbing characteristics), the exclusive use of
cellulosic fibers can deleteriously affect the durability of the
textile material. Accordingly, it may be desirable to use other
fibers (e.g., synthetic fibers) in combination with the cellulosic
fibers in order to achieve a desired level of durability. Thus, in
such embodiments, the cellulosic fibers can comprise about 95% or
less or about 90% or less, by weight, of the fibers present in the
textile material. More specifically, in certain embodiments, the
cellulosic fibers can comprise about 15% to about 95%, about 20% to
about 95%, about 25% to about 95%, about 30% to about 95%, or about
30% to about 90%, by weight, of the fibers present in the textile
material.
[0081] In certain embodiments of the invention, one or more of the
yarns in the textile material can comprise thermoplastic synthetic
fibers. For example, the yarn can comprise a blend of cellulosic
fibers and thermoplastic synthetic fibers. These thermoplastic
synthetic fibers typically are included in the textile material in
order to increase its durability to, for example, industrial
washing conditions. In particular, thermoplastic synthetic fibers
tend to be rather durable to abrasion and harsh washing conditions
employed in industrial laundry facilities and their inclusion in,
for example, a cellulosic fiber-containing spun yarn can increase
that yarns durability to such conditions. This increased durability
of the yarn, in turn, leads to an increased durability for the
textile material. Suitable thermoplastic synthetic fibers include,
but are not necessarily limited to, polyester fibers (e.g.,
poly(ethylene terephthalate) fibers, poly(propylene terephthalate)
fibers, poly(trimethylene terephthalate) fibers, poly(butylene
terephthalate) fibers, and blends thereof), polyamide fibers (e.g.,
nylon 6 fibers, nylon 6,6 fibers, nylon 4,6 fibers, and nylon 12
fibers), polyvinyl alcohol fibers, and combinations, mixtures, or
blends thereof.
[0082] In those embodiments in which the textile material comprises
thermoplastic synthetic fibers, the thermoplastic synthetic fibers
can be present in one of the pluralities or types of yarn used in
making the textile material in any suitable amount. In certain
preferred embodiments, the thermoplastic synthetic fibers comprise
about 65% or less, about 60% or less, or about 50% or less, by
weight, of the fibers present in one of the pluralities or types of
yarn used in making the textile material. In certain preferred
embodiments, the thermoplastic synthetic fibers comprise about 5%
or more or about 10% or more, by weight, of the fibers present in
one of the pluralities or types of yarn used in making the textile
material. Thus, in certain preferred embodiments, the thermoplastic
synthetic fibers comprise about 0% to about 65% (e.g., about 5% to
about 65%), about 5% to about 60%, or about 10% to about 50%, by
weight, of the fibers present in one of the pluralities or types of
yarn used in making the textile material.
[0083] In one preferred embodiment, the textile material comprises
a plurality of yarns comprising a blend of cellulosic fibers and
synthetic fibers (e.g., synthetic staple fibers). In this
embodiment, the synthetic fibers can be any of those described
above, with polyamide fibers (e.g., polyamide staple fibers) being
particularly preferred. In such an embodiment, the cellulosic
fibers comprise about 30% to about 90% (e.g., about 40% to about
90%, about 50% to about 90%, about 70% to about 90%, or about 75%
to about 90%), by weight, of the fibers present in the yarn, and
the polyamide fibers comprise about 10% to about 50% (e.g., about
10% to about 40%, about 10% to about 35%, about 10% to about 30%,
or about 10% to about 25%), by weight, of the fibers present in the
yarn.
[0084] In those embodiments in which the textile material comprises
thermoplastic synthetic fibers, the thermoplastic synthetic fibers
can be present in the textile material in any suitable amount. For
example, in certain embodiments, the thermoplastic synthetic fibers
can comprise about 1% or more, about 2.5% or more, about 5% or
more, about 7.5% or more, or about 10% or more, by weight, of the
fibers present in the textile material. The thermoplastic synthetic
fibers can comprise about 40% or less, about 35% or less, about 30%
or less, about 25% or less, about 20% or less, or about 15% or
less, by weight, of the fibers present in the textile material.
More specifically, in certain embodiments, the thermoplastic
synthetic fibers can comprise about 1% to about 40%, about 2.5% to
about 35%, about 5% to about 30% (e.g., about 5% to about 25%,
about 5% to about 20%, or about 5% to about 15%), or about 7.5% to
about 25% (e.g., about 7.5% to about 20%, or about 7.5% to about
15%), by weight, of the fibers present in the textile material.
[0085] As noted above, certain embodiments of the textile material
of the invention contain yarns comprising inherent flame resistant
fibers. As utilized herein, the term "inherent flame resistant
fibers" refers to synthetic fibers which, due to the chemical
composition of the material from which they are made, exhibit flame
resistance without the need for an additional flame retardant
treatment. In such embodiments, the inherent flame resistant fibers
can be any suitable inherent flame resistant fibers, such as
polyoxadiazole fibers, polysulfonamide fibers, poly(benzimidazole)
fibers, poly(phenylenesulfide) fibers, meta-aramid fibers,
para-aramid fibers, polypyridobisimidazole fibers,
polybenzylthiazole fibers, polybenzyloxazole fibers,
melamine-formaldehyde polymer fibers, phenol-formaldehyde polymer
fibers, oxidized polyacrylonitrile fibers, polyamide-imide fibers
and combinations, mixtures, or blends thereof. In certain
embodiments, the inherent flame resistant fibers are preferably
selected from the group consisting of polyoxadiazole fibers,
polysulfonamide fibers, poly(benzimidazole) fibers,
poly(phenylenesulfide) fibers, meta-aramid fibers, para-aramid
fibers, and combinations, mixtures, or blends thereof.
[0086] The inherent flame resistant fibers can be present in one of
the pluralities or types of yarn used in making the textile
material in any suitable amount. For example, in certain
embodiments, the inherent flame resistant fibers can comprise about
100%, by weight, of the fibers present in one of the pluralities or
types of yarn used in making the textile material. In those
embodiments in which the textile material comprises a yarn
containing a blend of cellulosic fibers and inherent flame
resistant fibers, the inherent flame resistant fibers can comprise
about 5% or more, about 10% or more, about 20% or more, about 30%
or more, about 40% or more, or about 50% or more, by weight, of the
fibers present in the yarn. Thus, in such embodiments, the inherent
flame resistant fibers can comprise about 5% to about 95% or about
10% to about 65%, by weight, of the fibers present in the yarn.
More preferably, in such an embodiment, the inherent flame
resistant fibers can comprise about 20% to about 50%, by weight, of
the fibers present in the yarn.
[0087] The inherent flame resistant fibers can be present in the
textile material in any suitable amount. Generally, the amount of
inherent flame resistant fibers included in the textile material
will depend upon the desired properties of the final textile
material. In certain embodiments, the inherent flame resistant
fibers can comprise about 20% or more, about 25% or more, about 30%
or more, about 35% or more, about 40% or more, or about 45% or
more, by weight, of the fibers present in the textile material. In
certain embodiments, the inherent flame resistant fibers can
comprise about 75% or less, about 70% or less, about 65% or less,
about 60% or less, about 55% or less, about 50% or less, about 45%
or less, or about 40% or less, by weight, of the fibers present in
the textile material. Thus, in certain embodiments, the inherent
flame resistant fibers can comprise about 20% to about 70%, about
25% to about 75% (e.g., about 25% to about 60%, about 25% to about
50%, about 25% to about 45%, or about 25% to about 40%), about 30%
to about 70%, about 35% to about 65%, about 40% to about 60%, or
about 45% to about 55%, by weight, of the fibers present in the
textile material.
[0088] The article of the invention preferably exhibits relatively
low levels of extractable formaldehyde. For example, the article of
the invention preferably exhibits an extractable formaldehyde
content about 90 ppm or less. The article of the invention more
preferably exhibits an extractable formaldehyde content of about 85
ppm or less, about 80 ppm or less, about 75 ppm or less, about 70
ppm or less, about 65 ppm or less, about 60 ppm or less, about 55
ppm or less, about 50 ppm or less, about 45 ppm or less, about 40
ppm or less, about 35 ppm or less, about 30 ppm or less, about 25
ppm or less, or about 20 ppm or less. The extractable formaldehyde
content can be measured by any suitable method, but preferably is
measured by the ISO method noted above.
[0089] The article of the invention can be made by any suitable
process. However, in another embodiment, the invention provides a
process for producing the article described above. The process
comprises the steps of: (a) providing a textile material having at
least one surface; (b) providing a phosphonium compound comprising
at least one phosphonium moiety; (c) providing a
nitrogen-containing cross-linking compound, the nitrogen-containing
cross-linking compound comprising two or more nitrogen-hydrogen
bonds; (d) applying the phosphonium compound and the
nitrogen-containing compound to at least a portion of the surface
of the textile material; (e) reacting the phosphorus-containing
compound and the nitrogen-containing cross-linking compound in a
condensation reaction to produce a first intermediate polymer on
the surface of the textile material; (f) exposing the textile
material to a Bronsted base to under conditions sufficient to
convert at least a portion of the phosphonium moieties to phosphine
moieties thereby producing a second intermediate polymer; (g)
oxidizing the second intermediate polymer on the surface of the
textile material by exposing the textile material to a suitable
oxidizing agent under conditions sufficient to oxidize at least a
portion of the phosphorus atoms in the polymer to a pentavalent
state thereby producing a phosphorus-containing polymer on the
surface of the textile material; and (h) exposing the textile
material to a Bronsted base to neutralize at least a portion of
acid generated by the preceding oxidation step.
[0090] The process for producing the article is very similar to the
process for producing the phosphorus-containing polymer described
above, with the polymer being produced on a textile material as
opposed to some other medium. Accordingly, the phosphonium
compound, nitrogen-containing cross-linking compound, Bronsted
base, oxidizing agent, and reaction conditions described above can
be used in this process embodiment of the invention. Furthermore,
any of the textile materials described above in connection with the
article embodiment can be used in this process.
[0091] The phosphonium compound and the nitrogen-containing
cross-linking compound can be applied to the textile material in
any suitable manner. For example, the phosphonium compound and the
nitrogen-containing cross-linking compound can be contained in a
treatment composition that is padded onto the textile material.
[0092] In order to accelerate the condensation reaction between the
phosphonium compound and the nitrogen-containing cross-linking
compound, the treated textile substrate can be heated to a
temperature sufficient for the phosphonium compound and the
nitrogen-containing cross-linking compound to react and produce an
intermediate polymer on the textile material. The time and elevated
temperature used in this step can be any suitable combination of
time and temperature that results in the reaction of the
phosphonium compound and nitrogen-containing cross-linking compound
to the desired degree. When the textile material comprises
cellulosic fibers, the time and elevated temperatures used in this
step can also promote the formation of covalent bonds between the
cellulosic fibers and the intermediate polymer produced by the
condensation reaction, which is believed to contribute to the
durability of the flame retardant treatment. However, care must be
taken not to use excessively high temperatures or excessively long
cure times that might result in excessive reaction of the
intermediate polymer with the cellulosic fibers, which might weaken
the cellulosic fibers and the textile material. Furthermore, it is
believed that the elevated temperatures used in the curing step can
allow the phosphonium compound and nitrogen-containing
cross-linking compound to diffuse into the cellulosic fibers where
they then react to form the intermediate polymer within the
cellulosic fibers. Suitable temperatures and times for this step
will vary depending upon the oven used and the speed with which
heat is transferred to the textile substrate, but suitable
conditions can range from temperatures of about 149.degree. C.
(300.degree. F.) to about 177.degree. C. (350.degree. F.) and times
from about 1 minute to about 3 minutes.
[0093] As with the process for producing the phosphorus-containing
polymer described above, the process of preparing the treated
textile material can entail additional oxidation and neutralization
steps. Also, the order of the process steps can be varied within
certain parameters. For example, the textile material can first be
oxidized as described above, then exposed to the Bronsted base,
then oxidized again, and finally exposed to the Bronsted base
again. The common parameter for any variation of the process steps
will be that the textile material is exposed to a Bronsted base,
then oxidized, and again exposed to a Bronsted base after the
oxidation. As discussed above, Applicants believe that exposure to
a Bronsted base prior to the oxidation step is needed in order to
convert a greater portion of the phosphorus moieties in the polymer
into a state that can be converted to phosphine oxide moieties in
the oxidation step.
[0094] After the treated textile material has been contacted with
the Bronsted base solution and the oxidizing agent as described
above, the treated textile material typically is rinsed to remove
any unreacted components from the treatment composition, any
residual oxidizing agent, and any residual components from the
neutralizing solution. The treated textile material can be rinsed
in any suitable medium, provided the medium does not degrade the
phosphorus-containing polymer. Typically, the treated textile
material is rinsed in water (e.g., running water) until the pH of
the water is relatively neutral, such as a pH of about 6 to about
8, or about 7. After rinsing, the treated textile material is dried
using suitable textile drying conditions.
[0095] If desired, the textile material can be treated with one or
more softening agents (also known as "softeners") to improve the
hand of the treated textile material. The softening agent selected
for this purpose should not have a deleterious effect on the
flammability of the resultant fabric. Suitable softeners include
polyolefins, alkoxylated alcohols (e.g., ethoxylated alcohols),
alkoxylated ester oils (e.g., ethoxylated ester oils), alkoxylated
fatty amines (e.g., ethoxylated tallow amine), alkyl glycerides,
alkylamines, quaternary alkylamines, halogenated waxes, halogenated
esters, silicone compounds, and mixtures thereof. In a preferred
embodiment, the softener is selected from the group consisting of
cationic softeners and nonionic softeners.
[0096] The softener can be present in the textile material in any
suitable amount. One suitable means for expressing the amount of
treatment composition that is applied to the textile material is
specifying the amount of softener that is applied to the textile
material as a percentage of the weight of the untreated textile
material (i.e., the textile material prior to the application of
the treatment composition described herein). This percentage can be
calculated by taking the weight of softener solids applied,
dividing this value by the weight of the untreated textile
material, and multiplying by 100%. Preferably, the softener is
present in the textile material in an amount of about 0.1% or more,
about 0.2% or more, or about 0.3% or more, by weight, based on the
weight of the untreated textile material. Preferably, the softener
is present in the textile material in an amount of about 10% or
less, about 9% or less, about 8% or less, about 7% or less, about
6% or less, or about 5% or less, by weight, based on the weight of
the untreated textile material. Thus, in certain preferred
embodiments, the softener is present in the textile material in an
amount of about 0.1% to about 10%, about 0.2% to about 9% (e.g.,
about 0.2% to about 8%, about 0.2% to about 7%, about 0.2% to about
6%, or about 0.2% to about 5%), or about 0.3% to about 8% (e.g.,
about 0.3% to about 7%, about 0.3% to about 6%, or about 0.3% to
about 5%), by weight, based on the weight of the untreated textile
material.
[0097] The softener can be applied to the textile material at any
suitable time. For example, the softener can be added to the
treatment composition described above (i.e., the treatment
composition comprising the precondensate compound and the
cross-linking composition) so that the softener is applied to the
textile material at the same time as the phosphorus-containing
polymer. The softener can also be applied to the textile material
following treatment of the textile material with the treatment
composition described above. In this instance, the softener
typically would be applied after the textile material has been
treated, dried, cured, oxidized, and, if desired, rinsed as
described above. In a preferred embodiment of the method described
herein, the softener is applied to the textile material in two
separate applications. The first application is incorporated into
the treatment composition (i.e., the treatment composition
comprising the phosphonium compound and the cross-linking
composition), and the second application is applied to the dry,
treated textile material following the steps of treatment, drying,
curing, oxidation, rinsing, and drying as described above. In this
embodiment, the softener is divided among the two applications so
that the final amount of softener applied to the treated textile
material falls within one of the ranges described above.
[0098] To further enhance the textile material's hand, the textile
material can optionally be treated using one or more mechanical
surface treatments. A mechanical surface treatment typically
relaxes stress imparted to the fabric during curing and fabric
handling, breaks up yarn bundles stiffened during curing, and
increases the tear strength of the treated fabric. Examples of
suitable mechanical surface treatments include treatment with
high-pressure streams of air or water (such as those described in
U.S. Pat. No. 4,918,795, U.S. Pat. No. 5,033,143, and U.S. Pat. No.
6,546,605), treatment with steam jets, needling, particle
bombardment, ice-blasting, tumbling, stone-washing, constricting
through a jet orifice, and treatment with mechanical vibration,
sharp bending, shear, or compression. A sanforizing process may be
used instead of, or in addition to, one or more of the above
processes to improve the fabric's hand and to control the fabric's
shrinkage. Additional mechanical treatments that may be used to
impart softness to the treated fabric, and which may also be
followed by a sanforizing process, include napping, napping with
diamond-coated napping wire, gritless sanding, patterned sanding
against an embossed surface, shot-peening, sand-blasting, brushing,
impregnated brush rolls, ultrasonic agitation, sueding, engraved or
patterned roll abrasion, and impacting against or with another
material, such as the same or a different fabric, abrasive
substrates, steel wool, diamond grit rolls, tungsten carbide rolls,
etched or scarred rolls, or sandpaper rolls.
Example 1
[0099] A fiber blend of 88% pima cotton, and 12% type (6,6) nylon
was carded, and drawn into a sliver. The sliver was subsequently
spun into a roving and ring spun into a textile yarn. Yarns used
for the warp were spun to a standard cotton count of 16/1 while the
fill yarns were spun to a cotton count of 12/1. The fabric was
woven using a yarn density of 90 ends per inch in the warp and 38
picks per inch in the fill direction in a 3.times.1 left-hand twill
pattern. The resulting woven fabric was scoured, mercerized and
range-dyed.
[0100] A flame retardant treatment formulation was created, which
contained the following components:
TABLE-US-00001 TABLE 1 Flame retardant treatment formulation for
the treatment of Sample 1. Component (Source) Amount
Tetrahydroxymethyl phosphonium urea 50 parts by weight condensate
(sold by Emerald Performance Materials under the trade name PYROSAN
.RTM. C-FR) Softening agent, which was a mixture of 4.4 parts by
weight ethoxylated alcohol and alkyl ester (sold by Boehme Filatex
under the trade name HIPOSOFT .RTM. SFBR) Urea (from Aldrich
Corporation) 8.8 parts by weight Sodium hydroxide solution, 12% by
weight 2 part by weight Water 34.8 parts by weight
[0101] The dyed, woven fabric was impregnated with the above
solution by padding, resulting in a wet pick-up of about 60% by
weight. The fabric was then dried for about 4 minutes in a
convection oven at a temperature of about 121.degree. C.
(250.degree. F.). The fabric was then cured in the same convection
oven at a temperature of about 177.degree. C. (350.degree. F.) for
2-3 minutes.
Oxidation and Neutralization
[0102] No further processing was done for this example. The fabric
was not oxidized or neutralized. The resulting treated fabric will
hereinafter be referred to as Sample 1.
Example 2
[0103] A fiber blend of 88% pima cotton, and 12% type (6,6) nylon
was carded, and drawn into a sliver. The sliver was subsequently
spun into a roving and ring spun into a textile yarn. Yarns used
for the warp were spun to a standard cotton count of 16/1 while the
fill yarns were spun to a cotton count of 12/1. The fabric was
woven using a yarn density of 90 ends per inch in the warp and 38
picks per inch in the fill direction in a 3.times.1 left-hand twill
pattern. The resulting woven fabric was scoured, mercerized and
range-dyed.
[0104] A flame retardant treatment formulation was created, which
contained the following components:
TABLE-US-00002 TABLE 2 Flame retardant treatment formulation for
the treatment of Sample 2. Component (Source) Amount
Tetrahydroxymethyl phosphonium urea 50 parts by weight condensate
(sold by Emerald Performance Materials under the trade name PYROSAN
.RTM. C-FR) Softening agent, which was a mixture of 4.4 parts by
weight ethoxylated alcohol and alkyl ester (sold by Boehme Filatex
under the trade name HIPOSOFT .RTM. SFBR) Urea (from Aldrich
Corporation) 8.8 parts by weight Sodium hydroxide solution, 12% by
weight 2 part by weight Water 34.8 parts by weight
[0105] The dyed, woven fabric was impregnated with the above
solution by padding, resulting in a wet pick-up of about 60% by
weight. The fabric was then dried for about 4 minutes in a
convection oven at a temperature of about 121.degree. C.
(250.degree. F.). The fabric was then cured in the same convection
oven at a temperature of about 177.degree. C. (350.degree. F.) for
2-3 minutes.
Oxidation and Neutralization
[0106] The fabric was then immersed in an aqueous solution
containing hydrogen peroxide (25% by weight) for about 60 seconds
at room temperature. The fabric was rinsed win warm tap water, and
immediately thereafter, the fabric was immersed in an aqueous
solution containing sodium hydroxide (6.0% by weight) for about 60
seconds at room temperature. The fabric was then rinsed in warm tap
water and dried. The resulting treated fabric will hereinafter be
referred to as Sample 2.
Example 3
[0107] A fiber blend of 88% pima cotton, and 12% type (6,6) nylon
was carded, and drawn into a sliver. The sliver was subsequently
spun into a roving and ring spun into a textile yarn. Yarns used
for the warp were spun to a standard cotton count of 16/1 while the
fill yarns were spun to a cotton count of 12/1. The fabric was
woven using a yarn density of 90 ends per inch in the warp and 38
picks per inch in the fill direction in a 3.times.1 left-hand twill
pattern. The resulting woven fabric was scoured, mercerized and
range-dyed.
[0108] A flame retardant treatment formulation was created, which
contained the following components:
TABLE-US-00003 TABLE 3 Flame retardant treatment formulation for
the treatment of Sample 3. Component (Source) Amount
Tetrahydroxymethyl phosphonium urea 50 parts by weight condensate
(sold by Emerald Performance Materials under the trade name PYROSAN
.RTM. C-FR) Softening agent, which was a mixture of 4.4 parts by
weight ethoxylated alcohol and alkyl ester (sold by Boehme Filatex
under the trade name HIPOSOFT .RTM. SFBR) Urea (from Aldrich
Corporation) 8.8 parts by weight Sodium hydroxide solution, 12% by
weight 2 part by weight Water 34.8 parts by weight
[0109] The dyed, woven fabric was impregnated with the above
solution by padding, resulting in a wet pick-up of about 60% by
weight. The fabric was then dried for about 4 minutes in a
convection oven at a temperature of about 121.degree. C.
(250.degree. F.). The fabric was then cured in the same convection
oven at a temperature of about 177.degree. C. (350.degree. F.) for
2-3 minutes.
Oxidation and Neutralization
[0110] The fabric was then immersed in an aqueous solution
containing sodium hydroxide (6% by weight) for about 60 seconds at
room temperature. The fabric was rinsed win warm tap water, and
immediately thereafter, the fabric was immersed in an aqueous
solution containing hydrogen peroxide (12.0% by weight) for about
60 seconds at room temperature. The fabric was then rinsed in warm
tap water and dried. The resulting treated fabric will hereinafter
be referred to as Sample 3.
Example 4
[0111] A fiber blend of 88% pima cotton, and 12% type (6,6) nylon
was carded, and drawn into a sliver. The sliver was subsequently
spun into a roving and ring spun into a textile yarn. Yarns used
for the warp were spun to a standard cotton count of 16/1 while the
fill yarns were spun to a cotton count of 12/1. The fabric was
woven using a yarn density of 90 ends per inch in the warp and 38
picks per inch in the fill direction in a 3.times.1 left-hand twill
pattern. The resulting woven fabric was scoured, mercerized and
range-dyed.
[0112] A flame retardant treatment formulation was created, which
contained the following components:
TABLE-US-00004 TABLE 4 Flame retardant treatment formulation for
the treatment of Sample 4. Component (Source) Amount
Tetrahydroxymethyl phosphonium urea 50 parts by weight condensate
(sold by Emerald Performance Materials under the trade name PYROSAN
.RTM. C-FR) Softening agent, which was a mixture of 4.4 parts by
weight ethoxylated alcohol and alkyl ester (sold by Boehme Filatex
under the trade name HIPOSOFT .RTM. SFBR) Urea (from Aldrich
Corporation) 8.8 parts by weight Sodium hydroxide solution, 12% by
weight 2 part by weight Water 34.8 parts by weight
[0113] The dyed, woven fabric was impregnated with the above
solution by padding, resulting in a wet pick-up of about 60% by
weight. The fabric was then dried for about 4 minutes in a
convection oven at a temperature of about 121.degree. C.
(250.degree. F.). The fabric was then cured in the same convection
oven at a temperature of about 177.degree. C. (350.degree. F.) for
2-3 minutes.
Oxidation and Neutralization
[0114] The fabric was then immersed in an aqueous solution
containing hydrogen peroxide (25% by weight) for about 60 seconds
at room temperature. The fabric was rinsed in warm tap water, and
immediately thereafter, the fabric was immersed in an aqueous
solution containing sodium hydroxide (6.0% by weight) at ambient
temperature for about 60 seconds. The fabric was then immersed
again in an aqueous solution containing hydrogen peroxide (25% by
weight) for about 60 seconds at room temperature and rinsed in warm
tap water. Immediately thereafter, the fabric was immersed in an
aqueous solution containing sodium hydroxide (6.0% by weight) at
ambient temperature for about 60 seconds. The fabric was then
rinsed in warm tap water and dried. The resulting treated fabric
will hereinafter be referred to as Sample 4.
Discussion of Examples 1-4
[0115] The relative percentage of phosphorus atoms present in
phosphine oxide, phosphonium, and phosphine moieties within the
polymer on each fabric sample was measured using the solid state
NMR spectroscopy technique described above. In particular, a
portion of each sample was cryogenically frozen and then ground to
a powder that was used in the solid state NMR measurements. The
values obtained by the NMR measurements were also qualitatively
verified by a calorimetric test procedure. In particular, a known
volume of an aqueous solution of hydrogen peroxide (15 mL of a 50%
by weight solution) was dispensed into an insulated vessel and the
temperature recorded using a precise digital thermometer. A 5 cm by
5 cm (2 inch by 2 inch) square piece of each sample fabric was
immersed in the hydrogen peroxide solution and the temperature of
the solution was allowed to equilibrate and then measured. The
difference in temperature between the final equilibrated solution
and the initial temperature was calculated and recorded. This
calorimetric test provides an indirect measure of the degree of
oxidation of the phosphorus atoms in the polymer on a fabric
sample. In particular, if a similar fabric substrate is used and
the amount of polymer on the fabric substrate is approximately
equal, a higher change in temperature indicates that a greater
percentage of the phosphorus atoms are present in lower oxidation
states, such as the P(III) oxidation state. As can be seen from
Table 5 below, this calorimetric measurement correlates well with
the direct measurements obtained by the NMR method.
TABLE-US-00005 TABLE 5 Summary of NMR data and calorimetry data for
Samples 1-4. Calculated Percentage of Phosphorus Atoms Phosphine
Sample Oxide Phosphonium Phosphine Calorimetry (.DELTA..degree. C.)
1 5 83 12 1.8 2 35 37 29 2.3 3 89 11 0 0.5 4 91 9 0 0.5
[0116] As can be seen from the data set forth in Table 5, the
phosphorus-containing polymers on Samples 3 and 4, which were
produced by a process of the invention (i.e., a process in which
the intermediate polymer is exposed to a Bronsted base prior to
oxidation), contain a greater percentage of phosphorus atoms in
phosphine oxide moieties than the polymers produced by other
processes. For example, a comparison of the phosphine oxide content
of the polymers on Samples 2, 3, and 4 reveals that the phosphine
oxide content of the polymers of the invention (i.e., Samples 3 and
4) was over 50 percentage points higher than the phosphine oxide
content of a polymer produced by a conventional process (i.e.,
Sample 2). Applicants submit that this result is very surprising
given, for example, the fact that the only difference between the
processes used to make Sample 2 and Sample 3 is the order of the
oxidation and neutralization steps; all other conditions were the
same.
[0117] Furthermore, Applicants submit that these differences in the
oxidation states of the phosphorus atoms in the
phosphorus-containing polymer are not a trivial matter. As
discussed above, the higher phosphine oxide content of the polymers
of the invention enable the polymer to better withstand the harsh
industrial washing conditions typically used to launder fabrics
treated with this type of polymer. Furthermore, the high oxidation
state of the phosphorus atoms in the polymer means that less heat
will be generated when the polymer (or a substrate on which the
polymer is disposed) is exposed to a flame or other high heat
event. With less heat being released by the polymer, an individual
wearing a fabric treated with the polymer is less likely to suffer
from harmful burns. In view of these differences, Applicants
believe that the polymers of the invention and substrates treated
with such polymers will prove particularly effective as flame
retardants and flame resistant garments.
[0118] All references, including publications, patent applications,
and patents, cited herein are hereby incorporated by reference to
the same extent as if each reference were individually and
specifically indicated to be incorporated by reference and were set
forth in its entirety herein.
[0119] The use of the terms "a" and "an" and "the" and similar
referents in the context of describing the subject matter of this
application (especially in the context of the following claims) are
to be construed to cover both the singular and the plural, unless
otherwise indicated herein or clearly contradicted by context. The
terms "comprising," "having," "including," and "containing" are to
be construed as open-ended terms (i.e., meaning "including, but not
limited to,") unless otherwise noted. Recitation of ranges of
values herein are merely intended to serve as a shorthand method of
referring individually to each separate value falling within the
range, unless otherwise indicated herein, and each separate value
is incorporated into the specification as if it were individually
recited herein. All methods described herein can be performed in
any suitable order unless otherwise indicated herein or otherwise
clearly contradicted by context. The use of any and all examples,
or exemplary language (e.g., "such as") provided herein, is
intended merely to better illuminate the subject matter of the
application and does not pose a limitation on the scope of the
subject matter unless otherwise claimed. No language in the
specification should be construed as indicating any non-claimed
element as essential to the practice of the subject matter
described herein.
[0120] Preferred embodiments of the subject matter of this
application are described herein, including the best mode known to
the inventors for carrying out the claimed subject matter.
Variations of those preferred embodiments may become apparent to
those of ordinary skill in the art upon reading the foregoing
description. The inventors expect skilled artisans to employ such
variations as appropriate, and the inventors intend for the subject
matter described herein to be practiced otherwise than as
specifically described herein. Accordingly, this disclosure
includes all modifications and equivalents of the subject matter
recited in the claims appended hereto as permitted by applicable
law. Moreover, any combination of the above-described elements in
all possible variations thereof is encompassed by the present
disclosure unless otherwise indicated herein or otherwise clearly
contradicted by context.
* * * * *