U.S. patent application number 13/524578 was filed with the patent office on 2012-10-04 for stable, water-soluble near infrared dyes.
This patent application is currently assigned to EPOLIN, INC.. Invention is credited to MURRAY S. COHEN.
Application Number | 20120248389 13/524578 |
Document ID | / |
Family ID | 41087961 |
Filed Date | 2012-10-04 |
United States Patent
Application |
20120248389 |
Kind Code |
A1 |
COHEN; MURRAY S. |
October 4, 2012 |
STABLE, WATER-SOLUBLE NEAR INFRARED DYES
Abstract
The synthesis of stable, water-soluble tris and tetrakis aminium
dyes. More particularly, carboxylic-acid modified tris and tetrakis
dye intermediates, as well as salts and near-infrared dyes formed
therefrom, as well as compositions including the dyes.
Inventors: |
COHEN; MURRAY S.;
(MORRISTOWN, NJ) |
Assignee: |
EPOLIN, INC.
NEWARK
NJ
|
Family ID: |
41087961 |
Appl. No.: |
13/524578 |
Filed: |
June 15, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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12051238 |
Mar 19, 2008 |
8227637 |
|
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13524578 |
|
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Current U.S.
Class: |
252/582 ;
524/239; 552/301; 562/457 |
Current CPC
Class: |
C09B 67/0013 20130101;
C07C 229/18 20130101; C09B 67/009 20130101 |
Class at
Publication: |
252/582 ;
552/301; 562/457; 524/239 |
International
Class: |
C07C 229/18 20060101
C07C229/18; C08K 5/18 20060101 C08K005/18; C09D 11/00 20060101
C09D011/00; C08K 3/20 20060101 C08K003/20; C07C 251/20 20060101
C07C251/20; G02B 5/20 20060101 G02B005/20 |
Claims
1-10. (canceled)
11. A compound of the formula: ##STR00039## where R is dimethylene
or where R has the formula R.sup.3CH.sub.2CH.sub.2-- and R.sup.3 is
methylene or a C.sub.2 to C.sub.10 polymethylene group of the
formula --(CH.sub.2).sub.n-- where 2.ltoreq.n.ltoreq.10.
12. A compound of claim 11 which has the formula: ##STR00040##
13. A salt produced from the compound of claim 11, the salt having
the formula: ##STR00041## wherein R.sup.1.dbd.Na.sup.+, K.sup.+,
NH.sub.4.sup.+, (CH.sub.3).sub.4N.sup.+, (CH.sub.3).sub.3NH.sup.+,
(R.sup.2).sub.3NH.sup.+ or R.sup.2NH.sub.4.sup.+, and
R.sup.2.dbd.CH.sub.3(CH.sub.2).sub.n, wherein n=2 to 10.
14. A monovalent dye salt produced from the salt of claim 13, the
dye having the formula: ##STR00042## wherein X.dbd.NO.sub.3.sup.-,
SbF.sub.6.sup.-, PF.sub.6.sup.-, BF.sub.4.sup.-, I.sup.-, Cl.sup.-,
Br.sup.- or CH.sub.3SO.sub.3.sup.-.
15. A divalent dye salt produced from the salt of claim 13, the dye
having the formula: ##STR00043## wherein X.dbd.NO.sub.3.sup.-,
SbF.sub.6.sup.-, PF.sub.6.sup.-, BF.sub.4.sup.-, I.sup.-, Cl.sup.-,
Br.sup.- or CH.sub.3SO.sub.3.sup.-.
16-23. (canceled)
24. A water-soluble polymeric composition comprising a blend of the
dye of claim 14 and a water-soluble polymer.
25. An aqueous composition comprising the dye of claim 14, a
water-soluble polymer and water.
26. A water-soluble polymeric composition comprising a blend of the
dye of claim 15 and a water-soluble polymer.
27. An aqueous composition comprising the dye of claim 15, a
water-soluble polymer and water.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to the synthesis of tris and tetrakis
aminium dyes. More particularly, the invention pertains to aminium
dye precursors, as well as salts and near infrared (IR) dyes formed
therefrom.
[0003] 2. Description of the Related Art
[0004] Near IR dyes are well known in the art. The spectral
properties of infrared light absorbing aminium dyes was first
reported by Otto Neunhoeffer and Peter Heitmann (see Neunhoeffer et
al., Chemische Berichte 92, 245-251 (1959) and Neunhoeffer et al.,
Chemische Berichte 94, 2511-2515 (1961)). Subsequent development of
these dyes at the American Cyanamid Company of Stamford, Conn. by
Peter Susi and colleagues is reported in U.S. Pat. Nos. 3,341,464,
3,440,257, 3,484,467, 3,575,871, 3,631,147, 3,637,769, 3,670,025
and 3,709,830 to Susi et. al., as well as U.S. Pat. No. 3,400,156
(Milionis et al.), U.S. Pat. No. 3,962,290 (Grosso) and U.S. Pat.
No. 5,686,639 (Cohen et al.), the disclosures of which are
incorporated herein by reference. Various other patents disclose
methods of preparation of intermediates and the use of such aminium
salts as near infrared dyes.
[0005] In general these dyes have the property of passing light in
the visible portion of the spectrum (450 to 700 nanometers) and
absorbing strongly in the near IR portion of the spectrum (900 to
1300 nanometers). By their use, it is possible to sequester about
35 to 50 percent of the sun's total energy. The amount is much
higher when absorbing radiation from tungsten filament lamps. These
dyes can be incorporated in a variety of plastics and can be used
as sunglasses, welding shields, laser protection eyewear, windows,
television filters, projection lenses and other products which can
attenuate the heat from radiant sources or absorb specific laser
radiation. As described in the referenced patents, the dye is
incorporated into plastic film or sheet by molding the plastic with
the dye, imbibing the dye into the preformed plastic sheet or by
forming the sheet by cell casting and polymerizing the
polymerizable monomer containing the dissolved dye.
[0006] Near infrared dyes are commonly synthesized from tris and
tetrakis amines. These intermediates are converted into salts and
oxidized to form dyes. For example, U.S. Pat. No. 3,709,830
provides p-Quinonediimonium salts and their use as infrared
absorbers. This patent discloses the synthesis of
N,N',N'',N'''-tetrakis(4-[di(2-hydroxyethyl)amino]-phenyl)-p-benzoquinone-
bis(imonium hexafluoro-antimonate) by combining
N,N',N'',N'''-tetrakis(4-[di(2-hydroxyethyl)amino]phenyl)-p-phenylenediam-
ine with methanol and silver hexafluoroantimonate. This SbF.sub.6
salt is not water-soluble and other salts have minimal water
solubility. The present invention provides a new class of
water-soluble, near infrared dyes that are obtained by the
oxidation of carboxylic acid-modified tris or tetrakis amines.
These dyes allow a similar maximization of the frequency range of
absorption while at the same time allowing transmission in the
visible range to be as transparent as possible. Further, one
particular advantage offered by these water-soluble dyes is their
very high solubility in mixed aqueous coating systems. These
coatings are very thin (approx 0.5 mil to 1.0 mils). For example,
if the concentration of dye used in an 80 mil optical lens requires
0.1 to 0.5% of near infrared dye, then a thin coating would need a
concentration of dye 50-100 times as great, and approximately 4% by
weight of dye in the dry coating weight would be used in such a
coating. Accordingly, the present invention provides a solution to
the existing needs in the art.
SUMMARY OF THE INVENTION
[0007] The invention provides a compound of the formula:
##STR00001##
[0008] where R is dimethylene or where R has the formula
R.sup.3CH.sub.2CH.sub.2-- and R.sup.3 is methylene or a C.sub.2 to
C.sub.10 polymethylene group of the formula --(CH.sub.2).sub.n--
where 2.ltoreq.n.ltoreq.10.
[0009] The invention also provides a process for producing a
carboxyl-modified compound, comprising reacting a tris amine of the
formula:
##STR00002##
[0010] with an alkenyl-substituted carboxylic acid of the formula
RCOOH, where R is dimethylene or where R has the formula
R.sup.3CH.sub.2CH.sub.2-- and R.sup.3 is methylene or a C.sub.2 to
C.sub.10 polymethylene group of the formula --(CH.sub.2).sub.n--
where 2.ltoreq.n.ltoreq.10, to produce a carboxyl-modified compound
of the formula:
##STR00003##
[0011] The invention further provides a compound of the
formula:
##STR00004##
[0012] where R is dimethylene or where R has the formula
R.sup.3CH.sub.2CH.sub.2-- and R.sup.3 is methylene or a C.sub.2 to
C.sub.10 polymethylene group of the formula --(CH.sub.2).sub.n--
where 2.ltoreq.n.ltoreq.10
[0013] The invention also provides a process for producing a
carboxyl-modified compound, comprising reacting a tetrakis amine of
the formula:
##STR00005##
[0014] with an alkenyl-substituted carboxylic acid of the formula
RCOOH, where R is dimethylene or where R has the formula
R.sup.3CH.sub.2CH.sub.2-- and R.sup.3 is methylene or a C.sub.2 to
C.sub.10 polymethylene group of the formula --(CH.sub.2).sub.n--
where 2.ltoreq.n.ltoreq.10, to produce a carboxyl-modified compound
of the formula:
##STR00006##
DESCRIPTION OF THE INVENTION
[0015] The stable, water-soluble near infrared dyes of the
invention are synthesized from either tris or tetrakis amine
starting materials. Such tris amine starting materials have the
formula:
##STR00007##
[0016] Such tetrakis amine starting materials have the formula:
##STR00008##
[0017] With regard to tris dyes, a tris amine is modified by
reaction with an alkenyl-substituted carboxylic acid of the formula
RCOOH, where R is dimethylene or where R has the formula
R.sup.3CH.sub.2CH.sub.2-- and R.sup.3 is methylene or a C.sub.2 to
C.sub.10 polymethylene group of the formula --(CH.sub.2).sub.n--
where 2.ltoreq.n.ltoreq.10, to form a carboxyl-modified
compound:
##STR00009##
[0018] where R.sup.3 will bond to nitrogen. Suitable carboxylic
acid monomers non-exclusively include unsaturated aliphatic
monocarboxylic acids such as acrylic acid, methacrylic acid,
crotonic acid and oleic acid. Of these, acrylic acid is most
preferred, producing a tris di-2-carboxyethylaminophenyl amine
compound of the formula:
##STR00010##
[0019] Typically, the reaction is conducted by allowing the tris
amine to react with an excess of the carboxylic acid. The reaction
temperatures are ordinarily from about 20.degree. C. to about
70.degree. C., with 60.degree. C. most preferred. The reaction is
typically conducted for about 1 to about 3 hours and may be
catalyzed by acrylic acid itself, acetic acid and/or other
aliphatic carboxylic acids in amounts up to equimolar which is
typically added prior to the addition of the unsaturated carboxylic
acid. The product may be recovered by the addition of about 5 to
about 10 volumes of water, allowing solids to precipitate which are
separated by filtration and washed with water and air dried.
[0020] The carboxyl-modified compound is subsequently reacted with
a base such as compounds R.sup.1--OH, R.sup.1.sub.2CO.sub.3 or
R.sup.1HCO.sub.3, which forms a salt having the formula:
##STR00011##
[0021] wherein R.sup.1.dbd.Na.sup.+, K.sup.+, Ca.sup.++,
(CH.sub.3).sub.4N.sup.+, NH.sub.4.sup.+, (CH.sub.3).sub.3NH.sup.+,
(R.sup.2).sub.3NH.sup.+ or R.sup.2NH.sub.2.sup.+ and
R.sup.2.dbd.CH.sub.3(CH.sub.2).sub.n, wherein n=2 to 10. An example
of a salt produced from reaction with (R.sup.2).sub.3NH.sup.+ is
the formula:
##STR00012##
[0022] Weak bases, such as NH.sub.3, (CH.sub.3).sub.3N, NaHCO.sub.3
and CaCO.sub.3, may also be used, and these may also be defined as
a compound R.sup.1OH because NH.sub.3 exists as
NH.sub.4.sup.+OH.sup.-, (CH.sub.3).sub.3N as
(CH.sub.3).sub.3NH.sup.+OH.sup.-, NaHCO.sub.3 as
Na.sup.+OH.sup.-+CO.sub.2, and CaCO.sub.3 as
Ca.sup.++(OH.sup.-).sub.2+2CO.sub.2. Other amines, such as
NH.sub.4.sup.+OH.sup.- and R.sub.3NH.sup.+OH.sup.-, etc., may also
be used as compound R.sup.1OH. The reaction with the carboxylic
acid group thereby gives a salt as though derived from
R.sup.1OH.
[0023] When R above comprises an ethyl group, as is preferred, the
salt has the formula:
##STR00013##
[0024] The salt formation with R.sup.1OH depends upon the strength
of the base used. When a strong base is used, such as NaOH, KOH,
Ca(OH).sub.2, tetramethylammonium hydroxide or other quaternary
ammonium hydroxides, the carboxylic acid is almost completely
neutralized, achieving complete replacement of the acid hydrogen of
all the carboxylic acid groups. When a weak base is used, such as
NH.sub.3, NaHCO.sub.3 or (CH.sub.3).sub.3N, the ratio of free
--COOH groups to weak base salts varies with the base strength due
to competition with zwitterion formation. For example, when R is an
ethyl group and an NH.sub.4.sup.+OH.sup.- base is utilized, a
zwitterion may be formed having the formula:
##STR00014##
[0025] With the strong bases, the stoichiometry approaches about 1
mole of base for each --COOH group. When a weak base is used, the
ratio of base to --COOH is less than equimolar. The reaction
temperatures used in the salt formation reactions are not critical.
Ordinarily, temperatures from about 20.degree. C. to about
50.degree. C. are used.
[0026] Most preferably, the carboxyl-modified compound is reacted
with a strong base, such as NaOH. However, because the --N group is
a base and the --COOH group is an acid, in aqueous solution, an
H.sup.+ ion may be transferred from the carboxylic acid group to
the basic amine to form a zwitterion (hybrid ion), having the
formula:
##STR00015##
[0027] or when R comprises a dimethylene group, the zwitterion has
the formula:
##STR00016##
[0028] The zwitterion is simultaneously electrically charged and
electrically neutral as it contains equal positive and negative
charges, so that the net charge on the molecule is zero. This
typically occurs due to reaction with a weak base, such as
NaHCO.sub.3, NH.sub.3, R.sub.3N and other amines, such as
NH.sub.4.sup.+OH.sup.-, R.sub.3NH.sup.+OH.sup.-, etc. The reaction
with any one of the bases, both organic and inorganic, will give a
zwitterion corresponding to the degree of basicity of the base.
Thus, NaHCO.sub.3, and organic amines will have similar but
somewhat different isoelectric points (degree of internal salt
formation) than that of strong bases such as NaOH, KOH or even
CaCO.sub.3 and K.sub.2CO.sub.3. Even these to some small extent may
not go all the way to the corresponding salt. Zwitterions also can
form when there is a free --COOH group and an amine in close
proximity.
[0029] After formation of the salt, the dyes of the invention are
formed by oxidation of this salt with an oxidant. Suitable oxidants
non-exclusively include copper salts such as cupric chloride,
cupric bromide, cupric sulfate and acetate, as well as silver salts
including silver nitrate (AgNO.sub.3), silver acetate
(AgC.sub.2H.sub.3O.sub.2), silver hexafluoroantimonate
(AgSbF.sub.6) silver hexafluorophosphate (AgPF.sub.6). Cupric
chloride, cupric bromide, cupric sulfate and cupric nitrate are
also used. Generally any cupric or silver salt which is soluble to
an appreciable extent in a compatible organic solvent may be used
in the oxidation reaction. Other useful oxidants include
N-bromo-succinimide, FeCl.sub.3 or a peroxide, particularly alkyl
peroxides such as tert-butyl hydroperoxide or benzoyl peroxide.
However, these give intermediates which are suitable as will be
explained for substation with NaSbF.sub.6, NaPF.sub.6 or other
salts of strong acids. Oxidation of the tris salt forms a dye
having the formula:
##STR00017##
[0030] or the zwitterion:
##STR00018##
[0031] wherein X is preferably an anion of a strong acid and
preferably comprises NO.sub.3.sup.-, Cl.sup.-, Br.sup.-,
tetrafluoroborate (BF.sub.4.sup.-), hexafluorophosphate
(PF.sub.6.sup.-) or hexafluoroantimonate (SbF.sub.6.sup.-). Most
preferably, X comprises NO.sub.3.sup.-, SbF.sub.6.sup.- or
PF.sub.6.sup.-. All of the compounds represented by these formulas
(I)(A), (B) (and formula (II)(A), (B) and III(C), (D) as shown
below) are stable, water-soluble near IR dyes in that they absorb
electromagnetic radiation in the range of 900 nanometers to 1300
nanometers. Any of the above compounds may be blended with most
water-soluble polymers and/or stable aqueous latex formulations to
form IR absorbing compositions.
[0032] The oxidation reaction is preferably carried out in a mixed
aqueous-alcohol solvent in which the carboxyl-modified salt and the
oxidant are at least partially soluble. The solvent used is not
critical provided it is inert to the reactants and the product
under the reaction conditions. Water and methanol are preferred
solvents due to their ease of handling, however, other solvents,
such as dimethylformamide, dimethylacetamide and tetrahydrofuran
also give good results. The amount of the oxidant used in the
oxidation reaction is about one mole per mole of the
carboxyl-modified salt. The reaction temperatures used in the
oxidation are not critical. Ordinarily, temperatures from about
20.degree. C. to about 50.degree. C. are used. Generally, following
completion of the oxidation, any remaining oxidant is removed by
filtering and the product is isolated from solution by
precipitation with acetone. The product is then filtered off,
washed free of solvent and dried, according to standard
techniques.
[0033] Thereafter, the oxidized dye may be further treated by
displacing the ion X.sup.- of the ionized dye compound with one or
more counter-ions Y.sup.- to form another salt of the dye, having
the formula:
##STR00019##
[0034] where Y is preferably NO.sup.-.sub.3, SbF.sup.-.sub.6,
BF.sup.-.sub.4 or PF.sub.6.sup.-.
[0035] To effect this replacement of anions, the dye that is
formed, usually as a nitrate salt, is dissolved in methanol and
treated with an excess of a salt of the substituted counter ion. In
the case of NaSbF.sub.6, such treatment results in the
precipitation of sodium nitrate which is removed from the reaction
mixture by filtration. The product containing the substituted
anion, is precipitated by the addition of acetone.
[0036] This optional treatment can add a cation to the carboxylic
acid, forming a neutrally charged species of the dye which is more
stable and more easily isolated. However, in some cases the dye may
be made from the carboxylic acid itself.
[0037] Similar reactions apply with regard to tetrakis dyes using
similar procedures to prepare and isolate the tetrakis carboxylic
acid as the tris product. A tetrakis amine is modified by reaction
with an alkenyl-substituted carboxylic acid of the formula RCOOH,
where R is dimethylene or where R has the formula
R.sup.3CH.sub.2CH.sub.2-- and R.sup.3 is methylene or a C.sub.2 to
C.sub.10 polymethylene group of the formula --(CH.sub.2).sub.n--
where 2.ltoreq.n.ltoreq.10, to form a carboxyl-modified
compound:
##STR00020##
[0038] Suitable carboxylic acid monomers are those described
previously for the tris dyes. Most preferably, the carboxylic acid
is acrylic acid, producing a tetrakis-2-dicarboxyethylaminophenyl
phenylene diamine compound of the formula:
##STR00021##
[0039] The carboxyl-modified compound is subsequently reacted with
a base compound such as R.sup.1--OH, R.sup.1.sub.2CO.sub.3 or
R.sup.1HCO.sub.3 to form a salt having the formula:
##STR00022##
[0040] wherein R.sup.1.dbd.Na.sup.+, K.sup.+, Ca.sup.++,
(CH.sub.3).sub.4N.sup.+, NH.sub.4.sup.+, (CH.sub.3).sub.3NH.sup.+,
(R.sup.2).sub.3NH.sup.+ or R.sup.2NH.sub.2.sup.+ and
R.sup.2.dbd.CH.sub.3(CH.sub.2).sub.1, wherein n=2 to 10. As
described above, a compound R.sup.1--OH includes weak bases, such
as NH.sub.3, (CH.sub.3).sub.3N, NaHCO.sub.3 and CaCO.sub.3 and
other amines, such as NH.sup.+.sub.4OH.sup.- and
R.sub.3NH.sup.+OH.sup.-, etc, where reaction with the carboxylic
acid group gives a salt as though derived from R.sup.1OH as
previously mentioned.
[0041] The general conditions described for the tris compounds are
applicable to the preparation of carboxylate salts of the tetrakis
products.
[0042] When R comprises an ethyl group, the salt has the
formula:
##STR00023##
[0043] Most preferably, the carboxyl-modified compound is reacted
with a strong base, whereas a weak base may form a zwitterion
having the formula:
##STR00024##
[0044] or when R comprises an ethyl group, the zwitterion has the
formula:
##STR00025##
[0045] After formation of the salt, the dyes of the invention are
formed by oxidation of this salt with an oxidant. Suitable oxidants
and oxidation conditions are the same as described above for the
tris dyes. However, oxidation of the tetrakis salt can form two
dyes having the formulas (II)(A) and (II)(B), and II(C) and II(D),
to represent the mono and dioxidized dyes:
[0046] The monovalent dye salt:
##STR00026##
[0047] or the zwitterion:
##STR00027##
[0048] For the divalent dye salt:
##STR00028##
[0049] or the zwitterion:
##STR00029##
[0050] wherein X is preferably an anion of a strong acid and
preferably comprises NO.sub.3.sup.-, tetrafluoroborate,
hexafluorophosphate or hexafluoroantimonate. Most preferably, the
acid comprises the salt of a strong acid. Preferred oxidants and
oxidation conditions are the same as described above for the tris
dyes. All of the compounds represented by these formulas (II)(A),
(II)(B), (II)(C) and (II)(D) (and formulas (I)(A) and (I)(B) above)
are stable, water-soluble near IR dyes and any of the above
compounds may be blended with water-soluble polymers and lattices
or latex emulsion polymers such as those enumerated herein to form
IR absorbing compositions.
[0051] Thereafter, the oxidized dye may be further treated by
reacting the ion X of the ionized dye compound with one or more
counter-ions Y to form another salt of the dye, having the formula
as shown for mono and di-oxidized dyes as illustrated in A and B
below. Both the dyes are represented here as pure carboxylic acid
salts but their zwitterions would behave similarly.
[0052] Monovalent Dye Salt:
[0053] A.
##STR00030##
[0054] Divalent Dye Salt:
[0055] B.
##STR00031##
[0056] where Y is preferably NO.sup.-.sub.3, SbF.sup.-.sub.6,
BF.sup.-.sub.4 or PF.sub.6.sup.-.
[0057] Similar to the tris dyes, this optional treatment adds a
cation to the carboxylic acid, forming a neutrally charged species
of the dye which is more stable and more easily isolated.
[0058] These stable, water-soluble near IR dyes have many of the
same absorption properties described in earlier patents for near
infrared dyes such as those claimed in U.S. Pat. Nos. 3,341,464,
3,440,257, 3,484,467, 3,575,871, 3,631,147, 3,637,769, 3,670,025
and 3,709,830. All of the dyes described in these patents absorb
radiant energy in the near infrared portion of the spectrum, but
they differ from the dyes of the present invention in that the
present dyes are soluble in water and are environmentally safe to
use.
[0059] The dyes of the invention may be blended with water-soluble
polymers or lattices, or may be dissolved in aqueous solutions of
water-soluble polymers, forming blend compositions. The blends may
be coated onto a substrate or may be applied between two
substrates, or may be extruded and/or molded into objects after
partial or complete evaporation of water from the blends. Suitable
water-soluble polymers are commercially available and well known in
the art and non-exclusively include aqueous binders such as
polyvinyl alcohol, silanol-modified polyvinyl alcohol, salts of
partially hydrolyzed polyvinyl acetate, salts of hydrolyzed
polyvinyl chloride-acetate copolymers, polysaccharide, starch,
cationized starch, casein, gelatin, gelatin derivatives, cellulose
and water-soluble cellulose derivatives such as water-soluble
cellulose nitrate, water-soluble cellulose acetate, water-soluble
cellulose propionate, water-soluble carboxymethyl cellulose,
water-soluble hydroxyethyl cellulose, and water-soluble cellulose
ethers such as ethyl and methyl cellulose polyvinylpyrrolidone,
polyalkylene oxide and polyalkylene oxide derivative, aqueous
acrylic resins and copolymers of acrylic acid, such as polyacrylic
acid, methyl acrylate, methyl methacrylate, methylolacrylamide,
polyacrylamide and copolymers thereof, aqueous alkyd resins,
sulfonic acid salts of polystyrene and water-dispersible polymers
such as aqueous latexes, including styrene butadiene latex,
styrene-acryl latexes, and polyurethane latexes, and water-soluble
emulsions, such as acryl emulsions. These aqueous binders can be
used individually or in combination of two or more thereof. Of
particular interest are those polymers such as cellulose acetate,
propionate and natural products such as paper which have a natural
affinity for water-soluble dyes.
[0060] When blended with aqueous solutions of water-soluble
polymers, the dyes are preferably present in such the aqueous
solution in an amount of from about 0.1% to about 10.0% by weight
of the water plus the water-soluble polymer, preferably from about
4% to about 10% of the water plus the polymer, where the polymer
comprises from about 30% to about 50% of the remainder with water
comprising the balance. In most instances, parts or objects
fabricated from these water-soluble polymers/dye formulations have
a light path (thickness) from about 2 mils (50.8 .mu.m) to about 20
mils (508 .mu.m). However, there are applications in which it is
desirable to use a very thin dye coating to block the near infrared
portion of the spectrum. It is in that kind of application that the
water-soluble dyes have special value. The thickness of the dye
coating is usually less than about 0.1 mil (2.54 .mu.m) to about
0.2 mil (5.08 .mu.m). This requires dye concentrations in the
polymer that are 10 to 100 times the concentration used in a solid
plastic. The water-soluble dyes must be used in concentrations that
are much greater than that accessible with most dyes formulated in
plastic especially for so short a light path. Furthermore, a
coating does not experience the thermal stress found in an
injection molding operation. By using the water-soluble dye in an
aqueous substrate, one is not constrained by concentration limits
no matter how thin the coating.
[0061] In addition to being highly water soluble, the near infrared
dye compositions have a greater thermal stability and greater water
solubility than prior compositions. Accordingly, they are useful in
a variety of applications. For example, when blended with a host
polymer the dyes may be used to produce light-filtering or
light-sensing elements or devices, such as optical filters
including contact lenses, and filters for night vision devices,
which may be fabricated by one of several conventional methods,
such as injection molding. They are also useful as security inks.
In formulation with available water-soluble stabilizers as well as
other dyes, one may obtain tailored spectra meeting most
application requirements. The dyes may include other additives or
dyes to provide, for example, UV stabilization or a tailored
spectral curve. The dye compositions also are useful in infrared
elements in combination with other absorptive, reflective,
refractive, or diffractive elements for optical radiation from the
ultraviolet through the infrared.
[0062] The following examples serve to illustrate the
invention:
EXAMPLE 1
Preparation of .beta.-Alanine,
N,N',N''-(nitrilotri-4,1-phenylene)tris[N-2 carboxyethyl]
##STR00032##
[0064] To 25 grams (0.086 mole) tris p-amino phenyl amine, is added
75 grams (1.04 mole) of acrylic acid. The exotherm from the
addition rises the temperature to 40.degree. C. to 45.degree. C.
Heating is continued with stirring at 50.degree. C. for 2 to 21/2
hours after which water (200 ml) is added. The precipitated solids
are separated and washed repeatedly with water. The solids are
collected on a filter and allowed to air dry. The solids weigh 45
grams, (70% of theory); melting pt.=165.degree. C.-168.degree. C.
Calculated for C.sub.36H.sub.42N.sub.4 (based on atomic weights):
C, 59.83; H, 5.82; N, 7.76 Found: C, 59.34; H, 5.77; N, 7.65
EXAMPLE 2
Ammonium Salt of .beta.-alanine, N,N',N''-(nitrilotri
4,1-phenylene)tris N-2 carboxyethyl--Using Weak Base
##STR00033##
[0066] 5.0 grams of the carboxylic acid from Example 1 was treated
with 10 ml of concentrated ammonia in 50 ml of water. To this was
added 200 ml of acetone which precipitated a dark green solid. The
solid was washed on a filter with acetone and dried in vacuum. The
analysis shows this to be a partially ammoniated salt of the
carboxylic acid. Analysis for the mono ammonium salt is shown as
follows:
[0067] Calculated for C.sub.36H.sub.51N.sub.7O.sub.12: C, 55.80; H,
6.60; N, 12.67
[0068] Found: C, 54.20; H, 7.30; N, 13.28
EXAMPLE 3
Sodium Salt of .beta.-alanine, N,N',N'' nitrilotri 4,1-phenylene
tris N-2-carboxylethyl Using Strong Base
##STR00034##
[0070] 5.0 grams (0.0069 mole) of the carboxylic acid from example
1 was added to 20 ml of water. The slurry was stirred while adding
84 ml if 0.5 N NaOH (0.042 equiv). A solution forms which is
filtered to remove any insolubles. To the filtered solution there
is added 200 ml of acetone. A precipitate forms, washed with
acetone and dried. Product weight: 6.1 g.
[0071] Calculated for C.sub.36H.sub.36N.sub.4O.sub.12Na.sub.6: C,
50.58; H, 4.22; N, 6.56
EXAMPLE 4
Dye Obtained by Oxidation of the Free Acid .beta.-alanine, N,N',N''
nitrilotri 4,1-phenylene tris N-2-carboxylethyl
##STR00035##
[0073] 7.2 g (0.01 mole) of the parent carboxylic acid was
dissolved in warm methanol. Filter the solution to remove any
insolubles. Add 0.17 g (0.001 mole) of silver nitrate dissolved in
a minimum amount of water. Heat the resulting mixture for 2 hours
at 50.degree. C. Filter off the silver precipitate with the
addition of a celite filter aid (or another diatomaceous earth) and
add 3 volumes of acetone to the methanol-water filtrate. Collect
the solids that precipitate and wash them with acetone. Allow the
solids to air dry. The yield, 6.0 g (76% of theory) had a .lamda.
max=954 nm, melting pt.=116.degree. C.-120.degree. C.
EXAMPLE 5
Dye Obtained by Oxidation of the Ammonium Salt of .beta.-alanine,
N,N',N'' nitrilotri 4,1-phenylene tris N-2-carboxylethyl: Using a
Weak Base
##STR00036##
[0075] 25.0 g (0.0866 mole) of tris p-aminophenyl amine was placed
in a 500 ml flask to which was added 75 g (1.06 mole) of acrylic
acid. The exotherm was complete when the temperature reaches
45.degree. C. The mixture was heated with stifling for 2 hours at
50.degree. C. At this point 25.0 g (0.08 mole) of concentrated
ammonia was added and the reaction mixture was held at 50.degree.
C. for 30 minutes. Silver nitrate, 14.0 g (0.086 moles) was added
in a minimum quantity of water and stirred for 2 hours at
50.degree. C. The precipitated silver metal powder formed was
removed by vacuum filtration using a filter aid such as celite. The
filter cake was washed with three 25 ml portions of water. All
filtrates were combined to which was added 1.5 liters of acetone.
The solids that separate were allowed to settle and were recovered
by decanting the acetone--water--acrylic acid mixture. The
precipitated semi-solid was treated with 3.times.100 ml of acetone.
The material collected was places in a vacuum dessicater over
concentrated sulfuric acid and held under vacuum for 2 days. A
glass--like solid was obtained. The solid was dissolved in warm
methanol, filtered and the filtrate treated with 2.times. volume of
acetone. A green solid separated and was collected on a filter,
washed with acetone and air dried. The yield of product is 55 g
(79% of theory). The dye has a .lamda. max of 956 nm and
absorptivity of 18.0.
EXAMPLE 6
Preparation of .beta.-Alanine, N,N',N'',N'''-[1,4-phenylenebis
nitrilo-di-4,1-phenylene]tetrakis N-(2 carboxyethyl)
##STR00037##
[0077] 20 grams of
N,N',N'',N'''-tetrakis(p-aminophenyl)-p-phenylene-diamine is mixed
with 48.8 g of acrylic acid to give a slurry. This mixture reacts
spontaneously, increasing in temperatures to about 40.degree. C.
Continue to heat the stirred mixture at 50.degree. C. for 2 to 3
hours. At the end of the reaction 200 ml of water was added to wash
out the excess acrylic acid. The precipitated solids were removed
by filtration and washed with water. The solids were allowed to air
dry. The yield was 38.5 grams or 87% of theory; melting
pt.=137.degree. C.-138.degree. C. Analysis gave the following
results:
[0078] Calculated for C.sub.54H.sub.60O.sub.16N.sub.6: C, 61.36; H,
6.44; N, 7.94
[0079] Found: C, 60.25; H, 5.86; N, 8.01
EXAMPLE 7
Sodium Salt of .beta.-Alanine N,N',N'',N''' 1,4-phenylene
bis-nitrilo-di 4,1-phenylene]tetrakis N(2-carboxyethyl) Using a
Weak Base
##STR00038##
[0081] The above mixture was formed when 6.2 g (0.1 mole) of
tetrakis parent amine is added to 57.6 g (0.8 mole) of acrylic
acid. This mixture was heated at 50-60.degree. C. for 4 hours with
stifling. Add to the cooled solution over 1 hour 57.6 g (0.8 mole)
of sodium bicarbonate dissolved in 100 ml of water. There was
instantaneous gas evolution which gradually ceases during the
addition. Addition of 400 ml of acetone gave a dark green
precipitate. This was washed with acetone and dried in vacuum over
concentrated H.sub.2SO.sub.4 as desiccant. A sample was subjected
to analysis to give the following results:
[0082] Calculated for C.sub.54H.sub.56O.sub.16N.sub.6Na.sub.4
(assuming the product is the zwitterion):
[0083] C, 57.04; H, 4.93; N, 7.39; Na, 8.09
[0084] Found: C, 53.01; H, 4.58; N, 6.71; Na, 12.10
[0085] Calculated for C.sub.54H.sub.52O.sub.16N.sub.6Na.sub.8
(assuming the product is the fully neutralized salt):
[0086] C, 52.94; H, 4.25; N, 6.86; Na, 15.03
[0087] Found: C, 53.01; H, 4.58; N, 6.71; Na, 12.10
EXAMPLE 8
Dye from the Sodium Salt of .beta.-Alanine N,N',N'',N''' 1,
4-phenylene bis nitrilo-di 4,1-phenylenel tetrakis N(2
carboxyethyl) Using a Strong Base
[0088] 10.0 g (0.0095 mole) of N,N',N'',N''' tetrakis(p-amino
phenyl)-p-phenylene diamine was neutralized with eight equivalents
of 0.5 N sodium hydroxide (152.6 ml). To this solution there was
added 3.244 g (0.019 mole) of silver nitrate in 10 cm.sup.3 of warm
water. The solution darkened and was stirred while heating at
50.degree. C. for 21/2 hours. The precipitated silver was removed
by filtration using filter aid such as celite. The filter cake was
washed with 2.times.20 ml of water and the washings combined with
the filtrate. To this dark solution there was added 3.times. the
volume of acetone. A precipitate separated. It was allowed to
settle and the supernatant was decanted. The solid was collected on
a filter and was washed with 2.times.20 ml of acetone and allowed
to air dry. The dye had a .lamda. max in water of 1037 nm and an
absorptivity of 18.0.
EXAMPLE 9
Dye from the Sodium Salt of .beta.-Alanine N,N',N'',N''' 1,
4-phenylene bis nitrilo-di 4,1-phenylene]tetrakis N(2 carboxyethyl)
Using a Weak Base
[0089] 10.48 g (0.01 mole) of N,N',N'',N''' tetrakis(p-amino
phenyl)-p-phenylene diamine was added to 90 ml of water. The slurry
was stirred at room temperature as 6.72 g (0.08 mole) of sodium
bicarbonate was added portion wise to the slurry. Gas evolution
occurred with each addition but was easily controllable. When the
addition was complete, a dark solution formed. To this solution,
silver nitrate, 1.7 g (0.01 mole), was added in 10 ml of warm
water. The solution was stirred and held at 45.degree. C. for 1.5
hours. The silver precipitate was removed by filtration in vacuum
with the addition of filter aid such as celite. The dark aqueous
filtrate was added to 350 ml of acetone. The solid that separated
was washed with acetone. It was placed in a vacuum dessicator over
conc. Sulfuric acid. The yield of solid was 11.5 g or 94% of
theory; showed a color change at 203.degree. C. but no melting up
to 250.degree. C. The spectrum of this dye in methanol had a
.lamda. max of 913 nm whereas a spectrum in water shows a peak
absorption at 1030 nm.
EXAMPLE 10
Dye from the Ammonium Salt of .beta.-Alanine N,N',N'',N'''
1,4-phenylene bis nitrilo-di 4,1-phenylenel tetrakis N(2
carboxyethyl) Using a Weak Base
[0090] 31.6 g (0.03 mole) of N,N',N'',N''' tetrakis(p-amino
phenyl)-p-phenylene diamine was placed in a 500 ml beaker with a
magnetic stirring bar. To this was added 14.6 g of concentrated
(28%) ammonia in 75 ml of water. The solids went into solution. At
this point 12.2 g of silver nitrate dissolved in 50 ml of warm
water was added. The solution darkened and was stirred at
50.degree. C. After 1 hour an additional 14.6 g of concentrated
ammonia was added and stirred at 50.degree. C. for an additional
hour. A celite filter aid was added to the solution to aid
filtration by vacuum. The dark solution was then added to 500 ml of
acetone. A precipitate formed which was isolated by decanting the
supernatant liquid. The solids were washed with acetone to form a
dark solid. The yield, 31 g is 83% of theory; melting
pt.=156.degree. C.-159.degree. C. The spectrum of the product has a
.lamda. max at 950 nm.
[0091] While the present invention has been particularly shown and
described with reference to preferred embodiments, it will be
readily appreciated by those of ordinary skill in the art that
various changes and modifications may be made without departing
from the spirit and scope of the invention. It is intended that the
claims be interpreted to cover the disclosed embodiment, those
alternatives which have been discussed above and all equivalents
thereto.
* * * * *