Note: Descriptions are shown in the official language in which they were submitted.
- CA 02226849 1998-01-13 - -
42,452A-F 1 , , 7 ~ ,,, "" ,,~,.. ,
~''' ' 7 ' 7' ~ ,
POLYNITRILE OXIDES
The present invention relates to stable polynitrile oxides.
Nitrile oxides react with unsaturated compounds to form cyclic compounds. For
5 example, nitrile oxides reactwith a) olefins and alkynes to form isoxazolines and isoxazoles,
respectively; b) aldehydes and ketones to form 1,3,4-dioxazoles; c) thiocarbonyls to form
thiooxazoles; d) imino compounds to form 1,2,4-oxadiazolines; e) isocyanates to form 1,2,4-
oxadiazolinones; and fl carboxyls to form hydroximic acids. (See Grundmann and Grunanger,
Nitrile Oxides, Springer, NewYork, pp. 85-139, 1971.)
Nitrile oxides can be prepared by a number of methods, most notably from the
dehydrohalogenation of the corresponding hydroximic acid halide, which can be prepared by
the halogenation of the corresponding aldoxime. The aldoxime, in turn, can be prepared by
reacting the corresponding aldehyde with a hydroxyl amine. General methods that teach the
preparation of nitrile oxides are described in Nitrile Oxides, supra, pp.31-61.
Because nitrile oxides tend to dimerize in the absence of stabilizing groups, it is
desirable to either prepare the nitrile oxides in situ, or to prepare stabilized nitrile oxides.
Nitrile oxides can be stabilized by the presence of substituents, such as ethyl, methyl, methoxy,
or methylsulfide groups adjacentto the nitrile oxide group (see Nitrile Oxides, supra, p.14).
Examples of stable nitrile oxides, including stable bis-nitrile oxides are disclosed in Nitrile
20 Oxides, supra, pp.16-21; Izv. Akad. Nauk SSSR, Ser. Khim., No. 5, pp.1201-1203 (1991); and
izv.Akad.NaukSSSR,Ser.Khim.,No.7,pp.1609-1615(1991). Onesuchstablebis-nitrileoxide,
2,4,6-triethylbenzene-1,3-bis(nitrile oxide), has been shown to be useful for the vulcanization
of natural rubber.
None of the above-cited art suggests the use of stable polynitrile oxides as
25 curatives for latexes. It would be an advance in the artto cure latexes using a one-part, room-
temperature curative.
The present invention is a water-insoluble aqueous dispersion comprising a stable
polynitrile oxide represented by the structure:
G-(C g N +-O~)~
30 where x is an integer greater than 1, G is an aromatic, aliphatic, or cycloaliphatic group having
at least one substituent adjacent to each nitrile oxide group, the substituent characterized by
inhibiting dimerization of nitrile oxide, and being non-interfering with a reaction between
nitrile oxide groups and unsaturated groups.
In a second aspect, the present invention is a method of curing a latex having a35 polyunsaturated disperse phase, comprising the steps of:
a) mixing with the latex a water-insoluble, stable polynitrile oxide represented by
the structure:
G-(C = N +-~~)x
~MEI~E~ S~IE~T
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where x i5 an integer greater than 1, preferably an integer from 2 to 6, G is anaromatic, aliphatic, or cycloaliphatic group having at least one substituent
adjacent to each nitrile oxide group, the substituent characterized by inhibiting
dimerization of nitrile oxide, and being non-interfering with a reaction betweennitrile oxide groups and unsaturated groups; and
b) removing water from the mixture, preferably by evaporation.
In a further aspect, the present invention is a compound having the structure:
Ç5N+-O-
~
(R~) ~ X' Y'
n~
15 wherein each R' is independently C1-C12-alkyl, F, Cl, Br, I, O-C1-C12-alkyl, or S-C1-C12-alkyl; each
R~ is a substituent that does not spontaneously react with the nitrile oxide group; each n' is
independently 0, 1, or 2; n " is an integer greater than 1; each X' is independently a bond or a
connecting group; and Y' is a polyvalent radical containing an ether, ester, amide, amine,
carbonate, ketone, urethane, arylene, or thioether moiety; or each X' and Y' together are a
20 bond connecting the benzene rings.
The present invention provides a simple means of preparing one-part coating
systems that can be cured at room temperature without the release of by-products.
The polynitrile oxides suitable for the practice of the present invention are
hindered polynitrile oxides. The term "polynitrile oxide" is used herein to referto two or more
25 aromatic nitrile oxide groups per molecule. It is to be understood that the term "aromatic"
includes heteroaromatic moieties such as pyridines, furans and thiophenes. The term
"unsaturated" is used herein to denote a site of the type A=A', or A=A', where A is a carbon
atom, and A' is a carbon, oxygen, nitrogen, sulfur, or phosphorus atom. For the purposes of
this invention, a nitrile oxide group is not an unsaturated group. The term " polyunsaturated "
30 is used herein to denote more than one unsaturated group. The preferred unsaturated groups
include olefins and alkynes.
Each nitrile oxide is adjacent to at least one substituent that is 1 ) unreactive with
nitrile oxide and 2) non-interfering with the reaction between the nitrile oxide groups and
unsaturated groups, preferably olefinically or acetylenically unsaturated groups.
Traditionally, nitrile oxides are prepared in situ in the presence of an unsaturated r
substrate with which the nitrile oxides are intended to react. However, the stable polynitrile
oxide used as a curing agent in the present invention can be prepared separately and is
sufficiently stable in the absence of the reactive substrate to be effective as a curing agent.
--2--
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Preferably, the stable polynitrile oxide forms less than 10 percent, more preferably less than
5 percent, and most preferably less than 1 percent dimers in 30 days at room temperature.
Examples of hindered aromatic polynitrile oxides include:
(~C----N+--O ) i C----N+-O-
R~,R2 R~R7
R6 R8
R3 C----N+ - O -
( -O -N+--C ) ~ ( C--N+ - O~ ) n
R4
R~ ( C----N+ - O - ) n
(-O-N+--C)
where Rl, R2, and R3, and R4 are each independently H, R, halo, SH, SR, SOR, SO2R, hydroxy, or
OR, with the proviso that at least one of Rl, R2, R3, and R4 that is adjacent to a nitrile oxide
group is not H; R5, R6, R7, and R8 are each independently H, R, halo, S-H, SR, SOR, 502R,
hydroxy, or OR, wherein R is a C1-C12 linear, branched, or cyclic alkyl group, preferably a Cl-C4
25 linear or branched alkyl group, more preferably ethyl or methyl; or R5 and R6, or R7 and R8~
together with the carbon atoms to which they are attached, form a benzene ring, wherein at
least one of R5 or R7 is not H, and at least one of R6 or R8 is not H;iis 2 or 3; m and n are each 0,
1, or 2, and n + m 2 2, preferably 2 or 3.
Other examples of hindered aromatic polynitrile oxides include compounds
30 represented by the following structures:
( -O-N+----C~ C--N+-O- ) u
where R9, Rl~, R11, and Rl2are each independently H, R, halo, SH, SR, SOR, 5O2R, hydroxy, or OR
with the proviso that at least one of R9 and Rllis not H when a nitrile oxide group is adjacent to
--3--
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(-O-N+-- C)p (C a N+-O )r
R3 R3
R9 Rl~ (C a N+-O )r
(-O-N+ - C)~ 12 , and
~ ~ C -- Nt-O-)r
(-O-N+ a C) ~ R12
both R9 and R11, and at least one of R10 and R12 is not H when a nitrile oxide group is adjacent
to both R10 and R12; m, p, and r are each 0, 1, or 2, and p + r 2 2; X is CHz, C(R)2, carbonyl, O, S,
20 SO, SO2, NH, SO2NH, SO2NR, or NR; t and u are each 0, 1, 2, or 3; and t + u 2 2; Y is a bond,
CH2, C(R)2, carbonyl, O, S, SO, 5~2, NH, NR, 9,9'-fluoreno, or phenylene.
Examples of specific hindered aromatic polynitrile oxides that are suitable for the
practice of the present invention include the following compounds:
C, - N+-O-
2 ~
C - N+-O-
3 O-N+ - C C, - N+-O-
~ ' ~
~o2cH3
_-O-N+ a C ~ C -- N+-O
~ '
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~ ~~
O-N+-c C-N+-O-
-O-N+-C ~ C -- N+-O
~ , and
-O-N+ - C~ = N+-O
W~ .
Stable aliphatic or cycloaliphatic polynitrile oxides can be prepared from a
suitably functionalized aliphatic or cycloaliphatic polyaldehyde. The polyaldehyde can then be
reacted with hydroxylamine to form the polyaldoxime, which can then be treated with bleach
and caustic treatment to form the desired aliphatic polynitrile oxide.
A suitably functionalized aromatic mononitrile oxide or monoaldehyde can be
used to prepare a polynitrile oxide represented by the following formula:
~ - N+-O-
(R~)n~ X~ Y
n~
wherein each R' is independently Cl-C12-alkyl, F, Cl, Br, 1, O-C1-C12-alkyl, or S-C1-C12-alkyl; more
preferably ethyl, methyl, n-propyl, isopropyl, n-butyl, isobutyl, methoxy, ethoxy; most
preferably ethyl, methyl, or methoxy; each R~ is a substituent that does not spontaneously react
with the nitrile oxide group, preferably ethyl, methyl, n-propyl, isopropyl, n-butyl, isobutyl,
30 methoxy, ethoxy, F, Cl, Br, or l; each n' is independently 0, 1, or 2; n' is an integer greater than
1, preferably 2,3, or 4, more preferably 2 or 3, and most preferably 2; each X' is independently
a bond or a connecting group such as an alkylene, cycloalkylene, or arylene group, more
preferably a bond, a methylene group, or a phenylene group; and Y' is a polyvalent radical,
preferably a divalent radical, containing an ether, ester, amide, carbonate, ketone, urethane,
35 arylene, or thioether group; or each X' and Y' together are a bond connecting the benzene
rings.
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Suitablyfunctionalized hindered aromatic mononitrile oxides or monoaldehydes
preferably include 2,6-disubstituted benzonitrile oxides or benzaldehydes having an ester,
acetate, hydroxy, epoxy, fluorine, chlorine, bromine, or iodine group connected directly to the
benzene ring or indirectly through a connecting group. Preferably, the suitably functionalized
5 2,6-disubstituted benzonitrile oxide or benzaldehydes is represented by the following
structure:
Q
R
( R~ ) X ' - Z '
where R', R~, X', and n' are previously defined; Q is -C--N+O- or -CHO; and Z' is an ester,
acetate, amine, hydroxy, epoxy, amide, keto, aldehyde, fluorine, chlorine, bromine, or iodine
1 5 group.
For example, 3-hydroxymethyl-2,4,6-trimethylbenzonitrile oxide or its
corresponding benzaldehyde precursor can be: (a) transesterified with a diester or condensed
with a diacid chloride to form a dinitrile oxide diester; (b) reacted with phosgene to form a
dinitrile oxide containing a carbonate group; (c) reacted with a diisocyanate to form a dinitrile
20 oxide containing urethane groups; (d) reacted with a dibenzyl chloride to form a dinitrile oxide
containing two ether groups; (e) reacted with a diglycidyl ether to form a dinitrile oxide
containing ether groups and hydroxy groups reacted with an acid to form a dinitrile oxido
dibenzyl ether.
Similarly, the suitably functionalized hindered aromatic nitrile oxide can be
25 reacted with a second suitably functionalized hindered aromatic nitrile oxide to form a dinitrile
oxide. For example, 3-hydroxymethyl-2,4,6-trimethylbenzonitrile oxide can be reacted with
3-chloromethyl-2,6-dimethylbenzene nitrile oxide to form a bis(nitrile oxide) dimethyl ether.
Polynitrile oxides having a functionality of greater than 2 ffor example, a trinitrile
oxide) can readily be prepared by reacting a dinitrile oxide with a compound having more than
30 2 unsaturated sites. For example, 2,4,6-triethylbenzene-1,3-dinitrile oxide can be reacted with
trimethylol propane triacrylate to form the following trinitrile oxide:
c33c z-o-c~\c~2c~3
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An aqueous dispersion of the stable polynitrile oxide is prepared, then
advantageously combined with an aqueous dispersion of a polyunsaturated monomer or
polymer or a combination thereof, to make a stable multicomponent dispersion. The term
~ "stable multicomponent dispersion" is used herein to mean that microscopic mixing (and
5 therefore, the reaction rate) of the polynitrile oxide and the polyunsaturated monomer and/or
. polymer is slower than it would be in the absence of the aqueous medium. Preferably, the
extent of the reaction between the polynitrile oxide and polyunsaturated monomer and/or
polymer dispersions is less than 10 percent in 8 hours, more preferably less than 10 percent in 30
days, and most preferably less than 10 percent in 1 year.
The aqueous dispersion of the polynitrile oxide can be prepared by emulsifying an
emulsifiable concentrate of the polynitrile oxide. This concentrate can be prepared, for
example, by mixing a solution of the polynitrile oxide with a surfactant.
The polynitrile oxide may itself be prepared as a surfactant, for example, by
reacting an excess of a dinitrile oxide with a polyunsaturated surfactant:
Ar-(C-N+-O )2 + = = ~ X"
(excess)
I
~ ~ Ar-C-N+-O- ~ ~ Ar-C--N+-O-
\ \ X"
or, for example, by reacting a trinitrile oxide with a monounsaturated surfactant:
Ar-(C-N+-O )3 + = X"
C-N+-O
-O-N+-C-Ar ~
X "
where X" is a hydrophilic group, such as a poly(oxyethylene), a carboxylate, or a sulfate.
Other methods of forming a polynitrile oxide surfactant include reacting the
polynitrile oxide with a polymeric surfactant having polyunsaturation:
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I COOH
Ç=~ b o + R(C -- N+-O-)2
0cH2c9(oH)cH2oc-cH=cH2
COOH
1 ~ ~ RC - N+-O-
f=~_ b R ~, 'y
OCH2CH(OH)CH2OC ~C CH2
H
where b i5 an integer greater than 1.
Aqueous dispersions of polyunsaturated polymers are disperse polymers having a
plurality of untaturated sites, which dispersions can be prepared by emulsion polymerization of
suitable monomers or by emulsification of previously prepared polymers (artificial latexes).
Suitable emulsion polymers can be prepared from the emulsion polymerization of
a-olefinically unsaturated aromatic monomers and dienes, preferably conjugated dienes, such
as styrene-butadiene latex, ~-methylstyrene-butadiene latex, styrene-isoprene latex, and a-
methylstyrene-isoprene latex.
However, the unsaturated latexes need not be prepared from conjugated diene
monomers, but may be prepared by polymerizing or copolymerizing unsaturated monomers
containing unsaturated groups having different reactivity. For example, the emulsion
copolymerization of a monofunctional alkyl acrylate or methacrylate, such as methyl or butyl
acrylate or methacrylate, with a difunctional acrylate or methacrylate having a vinyl group and
a less reactive double bond, such as crotyl acrylate or methacrylate, can produce a latex having
a plurality of pendant olefin groups.
A suitably functionalized latex, which need not be unsaturated, may be post-
reacted with compounds that impart unsaturated sites to the latex, for example, by reacting a
latex containing carboxyl functionality, such as a
poly(methylmethacrylate/butylmethacrylate/methacrylic acid) latex, with glycidylmethacrylate. Similarly, a latex containing pendant benzyl chloride groups can be reacted with
a vinyl monomer containing a tertiary amine group to form the polyunsaturated latex.
Artificial latexes, particularly polyunsaturated triblock copolymers of unsaturated
aromatic monomers and conjugated dienes, such as ~-methylstyrene-butadiene-~-
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methylstyrene, ~-methylstyrene-isoprene-~-methylstyrene, styrene-isoprene-styrene, and
styrene-butadiene-styrene are also suitable.
Other suitable aqueous dispersions include those of polyester resins, such as
~ maleate- and fumarate-containing polyesters and vinylically and allylically unsaturated acrylate
5 copolyesters; butadiene-acrylonitrile copolymers; ethylene-propylene-dicyclopentadiene
~ terpolymers; polyisoprene; polybutadiene, including 1,2-polybutadiene; unsaturated
polyurethanes; and polyether copolymers and terpolymers containing at least two unsaturated
epoxide constituents, such as propylene oxide-allyl glycidyl ether copolymers and ethylene
oxide-epichlorohydrin-allyl glycidyl etherterpolymers.
Aqueous dispersions of polyunsaturated monomers include dispersions of
conjugated or non-conjugated monomers, particularly monomers having a boiling point
greaterthan 100~C.
The polynitrile oxide is used at an effective amount to cure the polyunsaturatedlatex. Preferably, the concentration of polynitrile oxide is in the range of about 0.01 to about
1.10 nitrile oxide groups per unsaturated group.
The following examples are for illustrative purposes only and are not intended to
limitthe scope of the invention.
Example 1 - Curing an S/B Latex with an Emulsifiable Concentrate of 2,4,6-Triethylbenzene-
1,3-Dinitrile Oxide
20 A. Preparation of a Polymeric Surfactant and an Emulsifiable Concentrate of
2,4,6-Triethylbenzene-1,3-Dinitrile Oxide
A polymeric surfactant suitable for forming an emulsifiable concentrate of the
dinitrile oxide was prepared in two stages as follows:
Stage 1 - Hydrophobic Monomer Polymerization
A mixture of 793.8 parts TERGITOL'~ NP-7 surfactant (a trademark of Union
Carbide) and 18.4 parts t-butyl peroctoate were heated to 90~C in a stirred glass reactor and
blanketed with an inert atmosphere of nitrogen. A mixture of 433.1 parts styrene, 144.4 parts
2-ethylhexyl acrylate, 35.0 parts glycidyl methacrylate and a separate feed of 18.4 parts t-butyl
peroctoate were added continuously and proportionately to the reactor over 1.5 hours. During
30 this addition period, the reaction temperature reached a maximum temperature of 99~C.
Stage 2 - Hydrophilic Monomer Polymerization
The following feed solutions were added continuously and proportionately to the
reactor over 1.5 hours with the reaction temperature decreasing from 99~C to 92~C: 1 ) 87.5
parts 2-acrylamido-2-methylpropane sulfonic acid (AMPS) admixed with 87.5 parts deionized
35 (Dl) water, and 41.0 parts dibutyl amine; 2) 1176.7 parts TERGlTOL'" NP-7; and 3) 0.7 parts
2-mercaptoethanol admixed with 15.8 parts Dl water. The reactor contents were maintained at
90~C for an additional 2 hours. The polymer/non-ionic/water reaction mixture (PC-3) was
transferred to a steam still and the residual monomers were removed with the aid of a vacuum.
g
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A solution containing 1.9 9 of 2,4,6-triethylbenzene-1,3-dinitrile oxide (TON-2)and 5.8 9 butyl benzyl phthalate was prepared and mixed with 1.1 9 of PC-3 along with 2.9 9 of
TERGlTOL'~ NP-7 to form the emulsifiable concentrate.
B. The Curing Step
The emulsifiable concentrate from Part A was diluted with 11.7 9 of distilled
water and shaken to form an aqueous dispersion. This aqueous dispersion was then added to
76.6 9 of a polyunsaturated styrene/butadiene/acrylic acid latex (54.7 percent styrene, 43.3
percent butadiene,2 percent acrylic acid) having a pH of 3.5 and containing 38.7 9 solids and
37.9 9 water. This material was cast into 10-mil (0.25 mm) films on a glass substrate and cured
10 upon evaporation of water, at room temperature for 24 hours. When a portion of the
resultant film (0.42 9) was mixed with 8.5 9 of toluene, the film swelled, but ddid not dissolve.
In contrast, a comparable film that was prepared in the same manner, but did not contain the
dinitrile oxide, was found to dissolve partially in toluene. Thus, the dinitrile oxide-treated film
was found to be more highly crosslinked than the control that does not contain the dinitrile
oxide curative.
Exam~ie 2 - Crosslinking of Crotyl Methacrylate-Containing Latex with TON-2
Phase (A): Synthesis of a Latex
A 5-L, five-necked round-bottomed flask equipped with a nitrogen inlet, a refluxcondenser connected to an oil bubbler with a nitrogen outlet, a mechanical stirrer, and five
20 feed streams was immersed into a water bath and purged with nitrogen a suspension of latex
seed (prepared from styrene/acrylic acid 96/4; median particle size 240 A; 40 weight percent;
22.28 9) and VERSENOLrU 120 chelating agent (a trademark of The Dow Chemical Company,
8.32 9 of 1 percent solution) in water (642.8 9) were placed into the flask and heated at 60~C.
Butyl acrylate (399.36 9), methyl methacrylate (357.6 9), and methacrylic acid (16.64 9) were
25 pre-mixed to give a basic monomer mixture (773.6 9). Using five syringes and syringe pumps,
the following components were added to the flask while constantly maintaining the nitrogen
atmosphere and the temperature of 60~C:
(a) crotyl methacrylate (43.2 9) and a portion of the basic monomer mixture
(40 9);
(b) the remaining basic monomer mixture (733.6 9);
(c) t-dodecyl mercaptan (16.649);
(d) the solution of t-butyl hydroperoxide (4.64 9 of 70 percent active; 3.25
percent active) and DOWFAX'U (a trademark of The Dow Chemical Company) 2EP
surfactant (17.76 9) in water (83.2 9); and
(e) the solution of sodium formaldehyde sulfoxylate (SFS, 2.52 9 in 28 9 of water). Y
Component (b) was added over the first five hours, followed by the addition of
component (a) over an additional hour. Components (c), (d), and (e) were added over six hours.
After the addition of all components, stirring at 60~C was continued for an additional hour.
--10-
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The resuiting latex was then filtered through a 200-mesh screen and cooled to ambient
temperature. The conversion was 99.4 percent, and the recovery 97.8 percent. This latex had
50.4 percent solids, and particles with a mean and median size of 1442 A and 1341 A,
~ respectively.
5 Phase (B): Crosslinking of a Coating
An emulsion of TON-2 (12.5 weight percent in ethyl benzoate/water) was
prepared by a slow addition of the solution of TON-2 (3.125 9) in ethyl benzoate (9.375 9) to a
solution of RHODAPEX'~ C0-436 surfactant (a trademark of Rhane Poulenc,0.215 9 of 58
percent aqueous solution) in water (12.285 9) with high shear. A portion (8.01 9) of this
10 emulsion was added to the crotyl methacrylate-containing latex (42.00 9) described in Phase
(A) of this example. The resulting latex/TON-2 mixture was cast and dried, and aged at 22~C
and 50 percent relative humidityfor 18 hours. A piece of the resulting film (about 1 9) was
isolated and weighed, then placed in a vial with toluene (35 mL). The mixture was shaken at
high speed for 1 hour, and the soluble phase was removed. The mass of the residual gel-state
polymer in a wet state was recorded and the wet gel was then dried in vacuo at 65~C. The mass
of the resulting dry gel was recorded, and the swell index (that is, the difference in weights of
wet gel and dry gel divided by the weight of a dry gel) and percent gel (that is, the ratio of
weights of dry gel and the initial sample multiplied by 100) measured. In this example, the film
prepared from the latex/TON-2 mixture hadsa swell index of 4.2 and 86.8 percent gel,
20 indicating a high degree of crosslinking. A reference coating prepared from the same latex,
but without TON-2 added dissolved completely, confirming the absence of crosslinking in latex
alone.
Example 3 - Crosslinking of Glycidyl Methacrylate- Containing Latex with TON-2
Phase (A): Synthesis of a Latex
To a 1-gallon reactor equipped with a reflux condenser, a mechanical stirrer, and
nitrogen inlet and outlet was placed a suspension of latex seed (prepared from styrene/acrylic
acid96/4;medianparticlesize270A;40weightpercent; 19.34g)andVERSENOL'4 120(15.299of 1 percent solution) in water (1255.32 9). The flask was maintained at a temperature of 90~C
under a nitrogen purge. The following components were simultaneously added to the flask
30 over 230 minutes:
(a) butyl acrylate (779.60 9) and methacrylic acid (91.72 9);
(b) methyl methacrylate (657.31 9) and t-dodecylmercaptan (15.29 9); and
(c) the solution of ammonium persulfate (7.64 9) and DOWFAX~" 2EP surfactant
(33.97 9) in water (152.86 9).
After all the components were added, stirring at 90~C was continued for 30
minutes. The resulting latex was then filtered through a 200-mesh screen and cooled to
ambienttemperature. This latex had 51.9 percentsolids, particleswith a median size of 1380A,
andapHof2.2.
1 1
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The latex (250 9) was adjusted to a pH of 7.8, whereupon water (Z0 9) and
4-methoxyphenol (0.20 9) were added. This solution was placed into the 500-mL,3-necked
round-bottomed flask equipped with an air inlet, a reflux condenser with an air outlet, and a
mechanical stirrer. The flask was immersed into a water bath, heated to 90~C, and the air-flow
was established. Glycidyl methacryiate (5.2 9) was added over 3 hours, and the resulting latex
was cooled to ambient temperature. A milky suspension with no coagulates was obtained,
having 46.3 percent solids.
Phase (B): Crosslinking of a Coating
An emulsion of TON-Z as prepared in Example 2 (12.5 weight percent in ethyl
benzoate/water; 8.01 9) was added to the glycidyl methacrylate-containing latex (65.34 9)
described in Phase (A) of this example. The resulting latex/TON-2 mixture was cast to give a
coating with 61.3 percent gel.
Exam,ole 4 - Crosslinking of S/B Latex with TON-2
The S/B latex used in this example was prepared using styrene (57.5 percent),
butadiene (38 percent with a 1,2: 1,4 ratio of 15/85), and acrylic acid (4.5 percent). An emulsion
of TON-2 (12.5 percent in toluene/water) was prepared by a slow addition of the solution of
TON-2 (3.125 9) in toluene (9 375 g) to a solution of RHODAPEX'~ C0-436 surfactant (0.215 g of
58 percent aqueous solution) in water (12.285 9) with high shear. A portion of this emulsion
(6.40 9) was added to the S/B latex (100.0 9), and toluene was evaporated off. The resulting
latex/TON-2 mixture gave a coating which had 90.9 percent gel, a swell index of 4.9, and a
tensile strength of 1032.2 psi.
Exam,~le 5 - Preparation Of Di(3-Fulmido-2,4,6-trimethyl)-benzyl Ether
Di(3-fulmido-2,4,6-trimethyl)-benzyl ether was prepared in two steps from
3-hydroxymethyl-2,4,6-trimethylbenzaldehyde, which was prepared according to A. P.
Yakubov et al. in Izv. Akd. Nauk SSR, Ser. Khim., No.7, pp.1609-1615.
To a flask fitted by a 10-cm Vigeux column to which was attached a Barret trap
and reflux condenser was added a mixture of 3-hydroxymethyl-2,4,6-trimethylbenzaldehyde
(23 9, 0.129 mole) and sulfuric acid (0.2 9,96 percent in 130 mL of benzene). The mixture was
refluxed vigorously for 60 minutes. Benzene was removed in vacuo and the crude product was
dissolved in chloroform (about 60 mL), whereupon isopropanol (about 200 mL) was added at
60~C. The mixture was cooled to 5~C, and a crystalline precipate was filtered and determined to
be di(3-formyl-2,4,6-trimethyl)benzyl ether (18.7 g,85 percent yield), m.p.158~C to 161~C.
To a flask containing di(3-formyl-2,4-6-trimethyl)benzyl ether (9.8 9, 0.029 mole)
and ethanol (110 mL) was added in one portion a solution of NaOH (4.64 9,0.116 mole) and
hydroxylamine hydrochloride (8.06 9,0.116 mole) in water (20 mL). The mixture was heated for ~f
2.5 hours with vigorous stirring, then cooled to 5~C, whereupon a crystalline precipitate was
filtered and washed with ethanol (30 mL) and water. The precipitate was predetermined to be
CA 02226849 1998-01-13
W O 97/03034 PCTrUS96/11499
di(3-hydroximinomethyl-2,4,6-trimethyl)benzyl ether (8.9 9, 83 percent yield), m.p. 210~C to
213~C.
To a flask maintained at 5~C and containing a vigorousiy stirred suspension of
di(3-hydroximinomethyl-2,4,6-trimethyl)benzyl ether (7.9 9 0.0215 mole) in methylene chloride
(100 mL) was added (NaOCI (53 mL of a 15 percent solution). The reaction mixture was stirred
for 2 hours at 5~C to 10~C, whereupon the organic layer was separated, and the aqueous phase
was extracted with methylene chloride (50 mL). The organic phases were combined, then
washed with water (3 x 200 mL). The solvent was then removed in vacuo, and the resultant
mixture was cooled to 20~C. A crystalline precipitate was filtered and determined to be
di(3-fulmido-2,4,6-trimethyl)benzyl ether (7.5 9, 96 percent yield), m.p.156~C to 158~C.
Infrared spectroscopy showed a strong narrow band at 2300 cm~l corresponding to nitrile
oxide.
