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United States Patent 0 "
3,743,665
Patented July 3, 1973
1
wherein each of X and Y is O or S, R1 is an alkyl, aralkyl
or aryl, all of which may be substituted by one or more
halogens, ——NO2, —CN, alkyl or alkoxy, and R2 is a
3,743,665
STABILIZED ISOCYANATE COMPOSITION
Kenji Naito, Katsuhiko Ogino, and Hiroshi Okudo,
Toyonaka, Michio Tanaka, Suita, Yoshio Kamatam,
bivalent hydrocarbon residue.
Referring to the general formulae the alkyl group for
R1 and the substituent thereof is exempli?ed by methyl,
Osaka, Hiroshi Mukai, Toyonaka, and Tatsuro Take
uchi, Suita, Japan, assignors to Takeda Chemical In
dustries, Ltd., Osaka, Japan
ethyl, propyl, i~propyl, butyl, s-butyl, i-butyl, t-butyl,
No Drawing. Filed June 19, 1970, Ser. No. 47,913
Int. Cl. C07c 119/04
US. Cl. 260-453 SP
pentyl, hexyl, dodecyl, decyl, or the like. It is preferable
_
that the alkyl group has carbon atoms not more than 12.
17 Clauns
10
ABSTRACT OF THE DISCLOSURE
The aralkyl group represented by R1 is exempli?ed by
benzyl, phenethyl or the like, and preferably those having
carbon atoms at most 12.
Stabilized organic isocyanate composition containing
The aryl group represented by R1 is exempli?ed by
an organic ester or esters of isocyanic acid such as xylene,
phenyl, tolyl, naphthyl or the like, and, preferably those
w,w’-diisocyanate in combination with a stabilizer which 15 having carbon atoms not more than 10.
The alkoxy group is exempli?ed by methoxy, ethoxy,
is one or more of the acyl isocyanates encompassed by
propoxy, i-propoxy, butoxy, s-butoxy, i-butoxy, t-butoxy,
the formula
pentyloxy, hexyloxy, decyloxy, dodecyloxy, or the like.
Among them, it is recommended that the alkoxy group is
R1-CX--NCY
R2 (CX—NCY) z
R1—SO2-NCO
20 that of at most 12 carbon atoms.
The halogen atoms include bromine, chlorine, ?uorine
or the like.
wherein each of X and Y is O or S, R1 is an alkyl, aralkyl,
The bivalent hydrocarbon residue represented by R2 is
aryl, all of which may be substituted by one or more
exempli?ed by methylene, ethylene, propylene, phenyl
halogens, —NO2, -CN, alkyl or alkoxy, and R2 is a
bivalent hydrocarbon residue, the amount of the acyl iso 25 ene, biphenylene or the like, however, preferably those
having carbon atoms not more than 12.
cyanate or acyl isocyanates being about 0.001 to 1.0
Among the acyl isocyanates shown by the general for
percent by weight relative to the organic isocyanate ester.
mulae, the commercially available or the easily prepara
The present invention also involves a method of stabiliz
ble are, for example, acetyl isocyanate, dichloroacetyl iso
ing an organic isocyanate ester by incorporating the afore
mentioned stabilizer or stabilizers therein.
30
cyanate, trichloroacetyl isocyanate, tri?uoroacetyl isocya
nate, nitroacetyl isocyanate, phenylacetyl isocyanate,
benzoyl isocyanate, o-chlorobenzoyl isocyanate, p-nitro
benzoyl isocyanate, thioacetyl isocyanate, thiobenzoyl iso
The present invention relates to a stabilized isocyanate
composition. More concretely, the present invention re
cyanate, p-chlorothiobenzoyl isocyanate, acetyl isothio
lates to an organic isocyanate composition stabilized 35 cyanate, benzoyl isothiocyanate, p-cyano benzoylisocya
against undesirable polymerization and coloration.
nate, terephthaloyl diisocyanate, isophthaloyl diisocya
In the present speci?cation as well as in claims, the
term “organic isocyanate” it to be construed as meaning
“organic ester or esters of isocyanic acid,” the ester having
nate, methanesulfonyl isocyanate, benzenesulfonyl iso
cyanate, o- or p-toluenesulfonyl isocyanate, o- or p-chloro
benzenesulfonyl isocyanate, p-methoxybenzoyl isocyanate
the structure of an ester between HNCO and an alcoholic 40 or the like.
or phenolic hydroxyl compound, and the ester may have
These acyl isocyanates are employed in this invention
one or more —NCO groups in its molecule. Organic iso
singly, in combination with one another or in combina
cyanates are unstable because of the high reactivity of
tion with one or more stabilizers.
their isocyanato groups, and have the consequent disad
The organic isocyanates, i.e. alcoholic or phenolic ester
vantage that they are liable to be deteriorated during stor 45 of isocyanic acid, are usually those simple organic isocy
age, becoming colored and giving rise to cyclic isocya
anates in which the -—NCO group is attached to a hy
nurates, dimers, oligomers and higher polymers.
Various stabilizers for incorporation in organic isocya
drocarbon residue. The hydrocarbon residue may be
straight, or cyclic, aliphatic or aromatic, mono- or poly
nates to improve stability on storage have previously been
valent and may also contain inert substituent such as
proposed, such as phenols, phosphites, acyl halides, car
bon dioxide, sulfur dioxide, N,N'-disubstituted thioureas
and phosphorus chlorides, but none of them has pro
halogen or alkoxy. Among the organic isocyanates, the
commercially available or the easily preparable ones in
clude, for example, such monoisocyanates as methyl iso
cyanate, ethyl isocyanate, phenyl isocyanate, benzyl iso
vided a satisfactory stabilization e?iect.
cyanate, xylyl isocyanate, etc., such diisocyanates as 2,4
It has been found unexpectedly by the present inventors
that the organic isocyanates can be stabilized against said 55 and 2,6-tolylene diisocyanates, 0-, m- and p-phenylene
diisocyanates, 4,4'-diphenylmethane diisocyanate, m- and
unfavorable coloration and polymerization by the incor
p-xylene w,w'-diisocyanate and a mixture of m-isomer
poration of a small amount of an acyl isocyanate as a
and p-isomer, 1,10-decamethylene diisocyanate, 1,6-hexa
stabilizer.
methylene diisocyanate, 1,4-cyclohexylene diisocyanate,
Therefore, it is the main object of the present inven
tion to provide an organic isocyanate composition which 60 4,4'-dicyclohexylmethane diisocyanate, 1,3- and 1,4-bis
isocyanatomethylcyclohexane, 4,4'-biphenylene diisocy
is stabilized against polymerization and coloration.
anate, 4,4'-methylene-bis(2 - methylphenyl)diisocyanate,
Another object of the present invention is to provide a
method for stabilizing an organic isocyanate against un
4,4'-meth_ylene-bis(2 - methoxyphenyl)diisocyanate, 1,5
naphthalene diisocyanate, 4,4’-diisocyanatodiphenylether,
favorable polymerization and coloration.
Said objects are realized by incorporating into the or 65 2,2’-bis(4»isocyanatophenyl)-propane, etc., and such poly
ganic isocyanate an effective amount of one or more of
isocyanates as 4,4’,4" - triphenlymethane triisocyanate,
acyl isocyanates which are represented by the formulae:
toluene-2,4,G-triisocyanate, etc.
The organic isocyanates may be employed singly, in
70
combination, or in a mixture of its isomers, for example,
xylene w,w’-diisocyanate may be any of o-, m- and p
isomers or a mixture of more than one of them.
3,743,665
'
3
4
The effective amount of the acyl isocyanate or acyl
isocyanates for stabilizing the organic isocyanates is usu
EXPERIMENT 1
ally about 0.00‘1% to 1% by weight, more preferably
XDI (m-isomer 70%, p-isomer 30%) prepared by ?rst,
about 0.03% to 0.2% by Weight, relative to the organic
phosgenating dimethylbenzene-w,w'-diamine and then sub
isocyanates to be Stabilized, and Said ingredients in the 5 jecting the product to repeated fractional distillation until
particular ratio are brought into an intimate contact with
its hydrolyzable chlorine content reaches 0.01%, is re
each other.
distilled. On the other hand, test samples of stabilizers
The Organic isocyanates are usually prepared by alloware weighed into as many 50 cc. clear colorless bottles,
ing the corresponding amines to react with phosgene and
respectively. The distilled XDI is poured in each of the
are recovered from the reaction mixture by means of dis 10 bottles and air within each bottle is replaced with nitro
tillation. The incorporation of the stabilizer may be made
gen gas. The bottles are sealed and stored. Every week 1
to a recovered isocyanate or alternatively to said reacgram each of the samples is taken out, and is dissolved
tion mixture containing thus produced organic isocya-
in 20 milliliters of toluene to examine the solubility of
nates. In the latter case, the reaction mixture in admix- 15 each sample.
ture with the stabilizer is preferably followed by the disThe results are as follows.
Amount of
Solubility in toluene after
the stabilizer
(percent) 1 week
Stabilizer
2 weeks
3 weeks
4 weeks
Stabilizer of this invention:
Trichloroacetyl isocyanate ....... -'__
. 05
...... -- Clear.
Tri?uoroacetyl isocyanate.
. 05
D0.
Dichloroacetyl isocyanate
0. 05
Do.
Benzoyl isocyanate. _ _.--_
0. 05
D0.
Benzenesulfonyl isocyanat
p-Toluenesulionyl isocyanate
0. 05
0. 05
D0
Do.
Thioacetyl isocyanate ..... ..
Benzoyl isothlocyanate. _ --.
0. 05
0. 05
Do.
Do.
Terephthaloyl diisocyanate.
0. 05
> Do.
0. 05
D0.
p-Cyanobenzoyl isocyanate.
Control:
::::.:::.- After 3 days, the composition itself is turbid and
0. 05
0. 05
0.05
0. 05
Triphenyl phosphit
Phosphorous pentachlorlde._
gives a number of precipitates in toluene.
-
0.05
Gelatiou..._- Turbidity ............... -..
Benzoyl chloride ........ _.
....
0.05
Clear ........... ._do ................... ..
Acetyiehlon'de....
..
0.05 _..-.do ..... .. Clear ...... .- Turbidity...
..
-..
1 0. 1
Geiation after 2 days
io.1 Clear.-...._- Clear ...... .. Turbidity...
Carbon dioxide..
Sulfur dioxide---
Phosgene ......................... .-
~
Turbidity after 4 days.
Gelation after 1 day.
Turbidity after 2 days.
Geiation after 2 days.
0.05
do
do
Clear
Turbidity.
1 Approximately.
'
tillation so as to obtain the stabilized isocyanate com-
It is also to be noted that the XDI compositions con
position containing the organic isocyanate and the sta~
taining any of the present stabilizers can be safely stored
bilizer.
‘10 for a long period of time (e.g._longer than one year)
Many organic isocyanates are unstable, but xylene w,w'Without causing any polymerization or coloring.
diisocyanate (hereinafter referred to as XDI) is particEXPERIMENT 2
ularly unstable. For example, when the hydrolyzable
'
~
chlorine content of XDI is less than 0.01 percent on
XDI (m-isomer 70%, p-isomer 30%) containing 0.01
weight basis, XDI sometimes is converted into a solid 45 percent ‘by weight of hydrolyzable chlorine ‘shows turbid
polymer or forms a turbid liquid containing a polymer
ity in relatively a short period of storage. Various sta
on storage for a few weeks. Even when no change in the
appearance of XDI is recognized, the formation of an
insoluble material is observed upon adding the stored
bilizers are added to this turbid XDI. The resulting mix
tures are distilled again to give stable XDI compositions.
To each of these XDI compositions, 0.1% of sodium
XDI into toluene. In this connection, polymerization of 50 cyanide is added and the mixture is allowed to stand
XDI can be intentionally accelerated by the addition of
a small amount of sodium cyanide.
According to the present invention, even such an XDI
containing a basic material, for example, sodium cyanide
at 15° C. so as to see if turbidity occurs. Portions of the
XDI compositions are stored in nitrogen-?lled bottles to
examine the solubility of 1 gram of each sample in 20
milliliters of toluene. The results are as follows.
‘
Amount of the
stabilizer Gelation by sodium
_
Stabilizer
(percent)
cyanide
Solubility in toluene after 4
weeks
_
Stabilizer of this invention:
Trichloroaeetylisoeyanate .... ..
0.1
Tri?uoroacetylisocyanate ..... ..
0.1
Benzenesulfouyl isocyanate“ .
0. 1
Thioacetyl isocyanate ......... ..
0. 1
p-Nitrobenzoyl isocyanate.
Control:
No stabilizer
-
~
~~---
0. 1
—‘-~-
~
M ~
do
1
>
.
Do.
Slightly turbid.
D0.
Clear.
“ " ‘ Immediate gelation-.- Composition itself shows tur
Benzoyl ehioride__-.
Carbon dioxide_-...
Unchanged forddays. Clear.
Do.
.-
Do.
N,N’-d.ibutylthiourea ......... .-
Do.
or the hydrolyzable chlorine in sa1d range can be stabi-
EXPERIMENT 3
'
-
v
_
d .
lized remarkably.
'
70
4,4’-d1phenylmethane dusocyanate, prepared by phos»
The followin ex eriments will serve to illustrate the
genating _p,p"methylene'dianiline aqdty PPYifYin$ the
resent inventiogn 850w,“ a an of usefulness and un_
product, is distilled. At 45° 0., the distillate 1S fractional
p
.
’
g,
p
_
_
_
_ _
obviousness of the present invention without limiting the
scope of this invention thereto.
'- ly poured in 50 cc. clear colorless bottles each bottles
previously containing weighed ‘portion of the followingv
75 stabilizers.
3,743,665
5
an effective amount of one or more of acyl isocyanates
represented by the formulae:
R1—CX-—NCY and RKCO-NCO);
days, 1 gram of each sample is added into 20 milliliters
of toluene, and the amount of insolubles formed is meas
ured.
wherein each of X and Y is O or S, R1 is an alkyl having
The results are as follows.
Amount of the
‘ ’
Stabilizer
6
which comprises incorporating into the organic isocyanate
After the air in each bottle is replaced with nitrogen '
gas, the bottles are sealed and stored at 60° C. After 15
Insolubles
stabilizer
in toluene
(percent) Precipitation
(percent)
Stabilizer of this invention;
Triehloroacetyl isocyanate .......... ..
Tri?uoroacetyl isocyanate ____ __
<0. 01
<0. 01
Benzenesulfonyl isocyanate. . . .
<0. 01
p-Cyanobenzoyl isocyanate. -
<0. 01
Thioacetyl isocyanate ______ _ .
<0. 01
Terephthaloyl diisocyanate. _._
<0. 01
Control;
No stahiliver
0,3
Pyrogallol __________________________ --
0. 03
Guaieol _________________ __
0. 05
Triphenyl phosphite ____ ._
1. 0
Phosphorus pentachloride
0.05
Benzoyl chloride.
0.05
Acetyl chloride. _
0. 05
Phosgene ______ --
0. 07
Carbon dioxide ____ - _
0. 8
Sulfur dioxide _________ __
0. 2
N ,N’-dibutylthiou.rea .............. -.~-
0. 76
an intimate admixture with one or more of acyl isocya
not more than 12 carbon atoms, aralkyl having at most
12 carbon atoms, or aryl having not more than 10 carbon
atoms, all of which may be substituted by one or more
halogens, -NO2, —ON, or alkoxy having at most 12 car
nates which are represented by the formulae:
bon atoms, and R2 is phenylene.
What is claimed is:
1. A stabilized organic isocyanate composition com
prising, as the main component, an organic isocyanate, in
10. A method as claimed in claim 9 ,wherein the
30 amount of the acyl isocyanate or acyl isocyanates is
about 0.001% to 1% by weight relative to the organic
wherein each of X and Y is O or S, R1 is an alkyl having
not more than 12 carbon atoms, aralkyl having at most
12 carbon atoms, aryl having not more than 10 carbon
atoms, all of which may be substituted by one or more
isocyanate.
11. A method as claimed in claim 9, wherein the acyl
isocyanate is trichloroacetyl isocyanate.
12. A method as claimed in claim 9,
halogens, -NO2, --CN, or alkoxy having at most 12 35
isocyanate is trifiuoroacetyl isocyanate.
carbon atoms, and R2 is phenylene, and the amount of
13. A method as claimed in claim 9,
the acyl isocyanate or acyl isocyanates being about 0.001
isocyanate is benzoyl isocyanate.
to 1.0 percent by weight relative to the organic isocyanate
14. A method as claimed in claim 9,
contained.
isocyanate is benzoyl isothiocyanate.
2. A composition as claimed in claim 1, wherein the
15. -A method as claimed in claim 9,
acyl isocyanate is trichloroacetyl isocyanate.
isocyanate is p-nitrobenzoyl isocyanate.
3. A composition as claimed in claim 1, wherein the
wherein the acyl
wherein the acyl
wherein the acyl
wherein the acyl
16. A method as claimed in claim 9, wherein the acyl
4. A composition as claimed in claim 1, wherein the 45 isocyanate is p-cyanobenzoyl isocyanate.
17. A method as claimed in claim 9, wherein the acyl
acyl isocyanate is benzoyl isocyanate.
isocyanate is terephthaloyl diisocyanate.
5. A composition as claimed in claim 1, wherein the
acyl isocyanate is tri?uoroacetyl isocyanate.
acyl isocyanate is benzoyl isothiocyanate.
’
6. A composition as claimed in claim 1, wherein the
acyl isocyanate is p-nitrobenzoyl isocyanate.
7. A composition as claimed in claim 1, wherein the
acyl isocyanate is p-cyanobenzoyl isocyanate.
8. A composition as claimed in claim 1, wherein the
acyl isocyanate is terephthaloyl diisocyanate.
References Cited
UNITED STATES PATENTS
50
3,330,849
7/1967
Ulrich ___________ __ 260-453
LEWIS GO'ITS, Primary Examiner
9. A method for stabilizing an organic isocyanate, 55 D. H. TORRENOE, Assistant Examiner
UNITED STATES PATENT OFFICE‘
CERTIFICATE OF CORRECTION
Patent No.
3 , 743 , 665
Dated Juli 3 ,
1973
Kenji Naito, Katsuhiko Ogino, Hiroshi Okudo,
lnvento?s)
Michio Tanaka, Yoshio Kamatani , Hiroshi Mukai
Tatsuro Takeuchi
It is certified that error appears in the above-identified patent
and that said Letters Patent are hereby corrected as shown below:
Column 1, between lines 6 and 7, under the title,
please‘ insert the following:
\
-- Claims priority, application Japan, JuneIZO, 1969,
Serial No.
48748/1969 ——.
Signed and sealed this 18th day of December 1973. I
(SEAL)
Attest:
EDWARD M. FLETCHER, JR.
At‘testing Officer
’
RENE D. TEGTMEYER
_
Acting Commissioner of Patents