Note: Descriptions are shown in the official language in which they were submitted.
13~4848
PROCESS FOR THE PRODUCTION OF POLYISOCYANATES
WHICH CONTAIN ISOCYANURATE GROUPS
BACKGROUND OF THE INVENTION
Numerous processes for the production of
isocyanurate-containing polyisocyanates are known.
Typical of such processes are those described in U.S.
Patents 3,248,372, 3,330,828, 3,645,979 and 3,996,223.
Typical of the catalysts described are tertiary amines
such as N,N-dialkylethanolamines (U.S. 3,248,372),
alkali metal and alkaline metal compounds (U.S.
3,330,828), organic phosphines (U.S. 3,645,9793, and
mixtures of Mannich bases and carbamic acid esters (U.S.
3,996,223). Although these references broadly indicate
that reaction temperatures ranging from as low as -40C
to as high as 200C can be used, in the examples the
temperatures used are generally less than 150C, with
relatively long reaction times. Thus, U.S. 3,248,372
utilizes temperatures of from 70 to 140C, with reaction
times ranging from 10 to almost 15 hours. U.S.
3,330,828 exemplifies reaction temperatures of from 30
to 65C with reaction times ranging from 10 minutes to
almost 5 hours. U.S. 3,645,979 exemplifies reaction
temperatures of from 60 to 120C, with reaction times
ranging from 6 minutes to over 5 hours. Finally, U.S.
3,996,223 exemplifies reaction temperatures of from 70
to 150C with reaction times ranging from 30 minutes to
6 hours.
As is apparent, many different compounds have
been used as catalysts. Furthermore, with both
aliphatic and aromatic diisocyanates, temperatures of
less than 100C are typically used due to the
instability of the catalysts at higher temperatures. In
addition the same catalyst cannot generally be used to
trimerize both aliphatic and aromatic diisocyanates.
133~848
Catalysts which contain both tertiary amine
groups and aliphatic hydroxy groups are known and are
used in the production of polyisocyanurate foams. See,
e.g., U.S. Patents 3,824,239, 3,824,240 and 4,026,840.
DESCRIPTION OF THE lNV ~:N LION
The present invention is directed to a process
for the preparation of a polyisocyanate, and preferably
a liquid polyisocyanate, having an isocyanurate
structure which comprises heating an organic
10 diisocyanate to a temperature of from 100 to 275C in
the presence of a catalytic amount of an organic
compound containing at least one aliphatic tertiary
amine group and at least one aliphatic hydroxy group and
having a molecular weight of no more than about 500 for
15 a period of from about 0.1 minute to about 360 minutes.
Starting isocyanates suitable for use in the
present invention include substantially any aromatic,
aliphatic and cycloaliphatic diisocyanate. In general,
such diisocyanates are represented by the formula:
R(NCO)2
in which R represents an organic group obtainable by
removal of the isocyanate groups from an organic
25 diisocyanate having a molecular weight of from about 112
to 1000, and preferably from about 140 to 400.
Preferred diisocyanates are those in which R represents
a divalent aliphatic hydrocarbon group having from 4 to
18 carbon atoms, a divalent cycloaliphatic hydrocarbon
30 group having from 5 to 15 carbon atoms, or a divalent
araliphatic hydrocarbon group having from 7 to 15 carbon
atoms. Examples of the organic diisocyanates which are
particularly suitable for the process include
tetramethylene diisocyanate; 1,6-hexamethylene
35 diisocyanate, dodecamethylene diisocyanate;
133~848
cyclohexane-1,3- and -1,4-diisocyanate; l-isocyanato-
3-isocyanatomethyl-3,5,5-trimethyl-cyclohexane
(isophorone diisocyanate or IPDI); bis-(4-isocyanato-
cyclohexyl)-methane; 1,3- and 1,4-bis-(isocyanato-
5 methyl)cyclohexane; bis-(4-isocyanato-3-methyl-
cyclohexyl)-methane; and ~ '-tetramethyl-xylylene
diisocyanate. Preferred diisocyanates are 1,6-hexa-
methylene diisocyanate, isophorone diisocyanate and
bis(4-isocyanatocyclohexyl)-methane. Mixtures of
10 diisocyanates can, of course, be used. In addition to
the organic diisocyanates containing aliphatically-
and/or cycloaliphatically- bound isocyanate groups
previously set forth, it is also possible in accordance
with the present invention to use aromatic diisocyanates
15 wherein R represents a difunctional aromatic hydrocarbon
radical having from 6 to 15 carbon atoms. Suitable
aromatic diisocyanates include 2,4-diisocyanato toluene,
2,6-diisocyanato toluene, and mixtures of these isomers;
4,4'-diisocyanato diphenyl methane and its isomeric
20 mixtures with 2,4'- and optionally 2,2'-diisocyanato
diphenyl methane; and 1,5-diisocyanato naphthalene. In
addition it is possible according to the present
invention to use mixtures of aromatic and aliphatic
isocyanates.
The catalysts of the present invention are
organic compounds which have molecular weights of no
more than about 500 and which contain at least one
aliphatic tertiary amine group and at least one
aliphatic hydroxy group. Specific compounds include
30 N,N,N'-trimethylaminoethylethanolamine;
N,N'-dimethyl-N,N'-bis(hydroxyethyl)ethylene diamine;
N-hydroxyethyl-N,N',N'-tetramethyldiethylene triamine;
dimethyl-ethanolamine; N,N,N',N'-tetramethyl-
amino-2-propanol; triethanolamine; N-methyl-
35 diethanolamine; 1-(2-hydroxyethyl)pyrrolidine;
- 1334848
l-methyl-2-pyrrolidine ethanol; N,N-diethylethanolamine;
N-isopropyldiethanolamine; N-t-butyldiethanolamine; N-
piperidine-ethanol; 4-(2-hydroxyethyl)morpholine;
N-ethyldiethanolamine; l-[N,N-bis(2-hydroxyethyl)amino]-
5 2-propanol; 1,4-piperazine-diethanol;
triisopropanolamine; 3-(~-hydroxyethyl)-oxazolidine;
l-piperazine propanol; and the like. Preferred are
those compounds having molecular weights of less than
about 250 and containing only one tertiary amine group.
When carrying out the process of the invention,
the amount of catalyst used is generally less than one
percent by weight (based on the combined weight of the
isocyanate and catalyst) and is preferably used in an
amount of from about 0.1 to about 0.9 percent by weight
15 and most preferably from about 0.3 to about 0.7 percent
by weight.
The reaction in accordance with the present
invention is carried out at a temperature of from 100C
to 275C, preferably at a temperature of from 125C to
20 250C, and most preferably at a temperature of from
150C to 250C. The reaction is carried out for a
period of from about 0.1 minutes to about 360 minutes,
preferably for from about 1 to about 180 minutes and
most preferably for from about 3 to about 10 minutes.
25 (These times exclude the heat-up and cool down periods).
In general, the higher the temperature, the shorter the
reaction time. It is also preferred that the reaction
be carried out in the absence of oxygen because the
product thus formed is substantially improved with
30 respect to color.
In the practice of the present invention, the
diisocyanate is introduced into a reaction vessel and
the catalyst is added thereto. Appropriate reaction
vessels are known in the art. It is preferred, however,
35 that a hot tube plug flow reaction be used.
--4--
1334848
It has also been found that use of hydroxy
compounds such as alcohols and diols (or their urethane
derivatives) will significantly enhance the catalytic
activity of the catalysts used.
When the reaction is carried out at a
temperature greater than 200C, a trimer-modified
isocyanate is formed which is storage stable at 25C
and, therefore, there is no need for the addition of an
acidic stopper. However, when the reaction is carried
10 out at a lower temperature (i.e., less than 200C), the
addition of an acidic stopper such as hydrogen chloride
(one equivalent of acidic compound per equivalent of
tertiary amine group) is required when the ratio of
tertiary nitrogen to NCO group is greater than 0.01
15 and/or when the ratio of total hydroxy group to NCO
group is greater than 0.02.
Several observations have been made when
following the present invention:
1. The catalyst lose most of their activity at
higher temperatures (200C or more) after a
short time. (See Example 10 vs. 46 or 9
vs. 47; Examples 1, 5, 6, 7). Therefore,
the addition of a stopper is not necessary.
2. The catalysts can be used as trimerization
catalysts for both aromatic and aliphatic
isocyanates. The catalysts can be used to
make mixed trimer products. (See Example
95).
3. The presence of oxygen inhibits the
catalyst and causes darkly colored products
(see Examples 64-67).
4. The catalysts give, with N2 purging, darker
colored products at higher temperatures.
For example, at 250C a color of APHA of
more than 200, while at 150C, APHA is 35.
- 13348~8
5. Hydroxy groups (or their urethane
derivative) enhance the activity of these
catalysts. The hydroxy groups can first be
converted to urethane groups (Example 4) or
added and heated directly to the reaction
temperature (Example 2).
6. The catalysts, when mixed with isocyanates
at ambient temperature (~25C) are stable
for extended periods of time yet still keep
their reactivity at high temperature
(>100C) as long as the ratio of tertiary
nitrogens to NCO groups is less than 0.01
and/or the ratio of total hydroxy groups to
NCO groups is less than 0.02. (See Examples
68-71).
7. In general, the more removed the OH group
is from the tertiary nitrogen group the
less reactive the catalyst. (Compare
Examples 10 and 12).
8. In general, the less sterically hindered
the tertiary nitrogen and the more OH
groups present in the molecule, the more
reactive the catalyst. (Compare Example 48
to Example 24).
9. Relative to point 2 above, the amino
alcohols appear to be better high
temperature catalysts for aliphatic
isocyanates than aromatic isocyanates which
is the opposite of what is found normally.
(Examples 48 and 86). However, at lower
temperatures (<200C), the reverse is true.
(Compare Examples 91 and 92 to Examples 56,
57 and 58).
The invention is further illustrated but is not
35 intended to be limited by the following examples in
-` 1334848
which all parts and percentages are by weight unless
otherwise specified.
All the examples were purged with dry nitrogen
to eliminate water vapor and oxygen. The latter
5 inhibits the catalyst and causes darker colored
products.
Example 1
To a 250 ml 3-neck flask were added 100 grams
of hexamethylene diisocyanate and 0.3 grams of
10 triethanolamine. The stirred reaction mixture was
heated over a 4 minute period to 250C, held for 2
minutes, then cooled over a 6 minute period to below
70C. The resulting clear liquid had an % NCO content
of 40.0% (this % NCO did not change after 40 months
15 storage at 25C). An IR analysis of the mixture gave
strong absorptions at 1692 cm 1 and 1466 cm 1 indicative
of trimer. Unreacted hexamethylene diisocyanate was
removed by thin layer distillation to afford a liquid
product with a viscosity of 4030 mPa.s at 25C and an
20 isocyanate content of 21.5%. The product contained
0.05% unreacted hexamethylene diisocyanate.
Example 2
To a 250 ml 3-neck flask were added 100 grams
of hexamethylene diisocyanate, 0.4 grams of
25 N-methyldiethanolamine, and 0.4 g n-butanol. The
stirred reaction mixture was heated over a 4 minute
period to 250C, held for 2 minutes and then cooled over
a 6 minute period to below 70C. The resulting clear
liquid had an % NCO content of 34.0%. An IR analysis
30 indicated trimerization.
Example 3
To a 250 ml 3-neck flask were added 100 grams
of hexamethylene diisocyanate and 0.4 grams of N-methyl-
diethanolamine. The reaction mixture was stirred at
35 25C until all the hydroxy groups had been converted to
1'3348~8
urethane groups affording an NCO content of 49.5%. The
stirred reaction mixture was then heated over a 4 minute
period to 250C, held for 2 minutes and then cooled over
a 6 minute period to below 70C. The resulting clear
5 liquid had an % NCO content for 39.3. An IR analysis
indicated trimerization.
Example 4
To a 250 ml 3-neck flask were added 100 grams
of hexamethylene diisocyanate, 0.4 grams of N-methyl-
10 diethanolamine, and 0.4 grams n-butanol. The reaction
mixture was stirred at 25C until all the hydroxy groups
had been converted to urethane groups affording an NCO
content of 49.1%. The stirred reaction mixture was then
heated over a 4 minute period to 250C, held for 2
15 minutes and then cooled over a 6 minute period to below
70C. The resulting clear liquid had an % NCO content
of 35.4%. An IR analysis indicated trimerization.
Example 5
To a feed tank was added a mixture of 100 parts
20 hexamethylene diisocyanate, 0.4 parts n-butanol and 0.2
parts l-(2-hydroxyethyl) pyrrolidine. This material was
then pumped, at 25C, through a hot tube plug flow
reactor at 265C. The heat-up from 25C to 265C
required 2.1 minutes. The reaction mixture was
25 maintained at 265C for 2.3 minutes and then quench
cooled to 40C. The isocyanate content of the resulting
reaction mixture was 41.9%. The unreacted hexamethylene
diisocyanate was removed by thin layer distillation to
af~ord a clear liquid product with a viscosity of 3390
30 mPa.s at 25C and an isocyanate content of 21.0%. The %
NCO did not change after 8 months storage at 25C. The
product contained 0.4% unreacted hexamethylene
diisocyanate.
1~4848
Example 6
The procedure of Example S was repeated using
100 parts of hexamethylene diisocyanate, 1.5 parts of
n-butanol and 0.15 parts of 1-(2-hydroxyethyl)
5 pyrrolidine. The isocyanate content of the resulting
reaction mixture was 38.6%. The unreacted hexamethylene
diisocyanate was removed by thin layer distillation to
afford a clear liquid product with a viscosity of 4710
mPa.s at 25C and an isocyanate content of 19.5%. The %
10 NCO did not change after 8 months storage at 25C. The
product contained 0.4% unreacted hexamethylene
diisocyanate.
Example 7
To a feed tank was added a mixture of 100 parts
15 hexamethylene diisocyanate, 4.4 parts n-butanol and 0.02
parts 1-(2-hydroxyethyl) pyrrolidine. This material was
then pumped, at 25C, through a preheater which brought
the mixture to about 160C. The mixture then entered a
stirred overflow reactor purged with nitrogen and was
20 held at 260C for an average residence time of 3.4
minutes. The overflow material was quench cooled to
about 40C and was found to have a 38.6% NCO content.
Unreacted hexamethylene diisocyanate was removed by thin
layer distillation to afford a clear liquid product with
25 a viscosity of 1910 mPa.s at 25C and an isocyanate
content of 18.0%. The % NCC did not change after 8
months storage at 25C. The product contained l.Qh
unreacted hexamethylene diisocyanates.
Examples 8-57
Using the procedure described in Example 2
above, the following trimerizations of aliphatic
isocyanates were carried out using the specified
reagents and conditions set forth in the table. HX is
hexAmethylene diisocyanate.
- 1334848
~ - 00 ~ ~ ~ O ~D
8 ~ o ~ ~o ~ ~ ~
Z C~ ~ ~ ~ ~ ~ ~ ;~
~P~ ~
o
C C~
4 0 0 0 0 0 0
a~
P E~--~
~ ~ ~î C C
0 u~ u~ u~ u~ u~ u~ u~ u~ u~ u~ u~ u~
g ~ ~ o ~ ~ g ~ g ~ og ~ g
~o o ~o O ~o ~0 ~o ~o o
--10--
13348~8
t~ot5~ t~oC`J o t~o
~ C~ ~ ~ ~ t~o
Z ~ Y;~ ~r ~ ~ ~ ~
~P ~
E~ `--
~ t~
o o o o O o
, ~~ ~ ~ ~ C~ C~J
P E
_ tL~ ~C
P E~ ~ t
C
? ~ s s
. L æ
r ~ ~ ~ ~ C
~ Z ~ ~ z .~ J .~
tn u~ q tntn tn ~q 0 tn tn tn tn t;q tn
t'tP~ r~ r~ ~ ~ ~ ~ rl. r~ r~ ~ ~ ~ ~ P~
O`J 0~ ~0~ 0~ ~0~ O`J
ro~ o oo o
ry
u~ ~ I~ t~O t~
--11--
1334818
~ ~ ~ ~ t~o ~
8 . _~,, ," ~
Z Y ~ ~ ~ ~ ~ ~
, .~
r~ ~,
o o o O o o
~ E~t~ t~ t~l t~ c~
~ t tLI
t~l
~î ~
C C
~r ~ ~ tL ~ tL L
r ,~ r~ ~ r~
- r- - r- ~ ~ ?~ ~ ~ r- ~
cr~Z~ L ~Z ~ r~
n L~
t~ t`~t~ t~ t~t~ t.~ td t~d t.~ c~ t~
O`J 0~ ~0~ 0~ ~ 0~ 0~
o o o o o o -
~4 r-l O _I O 0~1 0 ~1 0 0 ~1 0 ~ O O
tL~
7 o ~ ~ ~ ~
t~ t~i t.~ t~ c~1
--12--
~3348~8
o ~ . . ~ ,` ~ U~
y ~ U~ ~ oo C~
,~ C7
o o o o o o
, ~ ~ ~ ~ ~ ~ C~
E~
_
~ P
~,
~ ~ ~ ,, ,
@~
r ~ ~ ~;
I I I I
~ r~ r f~ rl
u ~ z ~ z c ~ c ~ z 1 ~ z ~ c
Lu~ u~ u~ u~ u~ u~ t~ u~ u~ u~ :q u~ u~ co u~
c~ ~ ~ J~ 4 J-) IJ 4 4 4 --~ ~ L
0~ 0~ 0~ 0~ ~ 0~ o~
O ~ O ~ ~ O O O o
0 ~00 ~0 .--10 0 ~0 ~10 0
o
r,~ rr) r,r
--13--
1334848
n l ~ o c~ ~
z ~ ~ J ~ ~ ~ ~ ~
._ o
-- O O O O O O
r ~ C~l
P E I~
r!
c~ ~-rl c~
~ E~ ~
r~
~ E~ ~
r~ ~î
!1 r~ ~ 5
~ C
a a ~ a
L r 1 r - ~ ~ ~r ~.r ~ ~ r r~
? c ~? c
~ - r r I .~
u ~ r' ~ r~
o~ o~ ~ 0~ 0~ 0~ ~J 0~ U~
o o o o o O o
~o ~00 ~o ~00 ~0 o ~o o
--14--
1334818
~ 1
Or -- ~ ~ ~ o
Q
Z t~ Y
U E~ `--
C U
., o
t ~ ,~, o ~, o
~ E ~
U~
~ ~a~
I
*
E~
C ~ C ~
?C cn C _ _~
~ U-~ ~ .
O `J ~ O `J ~0 ~ 0 ~ O `J 0~ `J 0 ~
o o o o o o o o -
ioo ~o ~' o~o ~o o ~o
a~
~I
o
13348~8
~ "
Q ~ . oo
y ~ oo o ~ U~
jZ:j X ~ ~ C~ ~ ~ `J
~l
o ~
~C~
._ o
o o o o o o
E~
o
v~ v~ vn v~ u~ cn v~ vn cn n v~ v~ vn cn cq v~
o~ ~o~ o~ ~ o~ o~ oc~
o o o o o o -
~o o~o ~o o ~o ~oo ~oo
~I
o
--16--
133~8~8
o,
Y
O E-~
C
O U~ O O O h'~
.
~ O ~ O
~ C a~ C L\ C ~ C _ C ~)
`_ L ~ ~ lL
_
;OC~ 0~ 0~10~_~ 0~_I 01~
~0 ~ o ~ ~ o ~ C~i o
--17--`
1334848
~ 1J
O ~D
o,
o ~ ~ ,~ o o~
Y ~ ~ ~ C~ C`~
o ~
C C~
n o o o o o
o o o o C~ o
J~ ~ a
-' -~ _,
a
~ ~ C ~
~ i#? a ~ ~ a L ~ a
c, I ~ c _~ c~
~)`--_ C~ ~ ~ ~ f t~l ~
~,~,' ~ ~ ^ I ~ z ~ r ~ ~ ~ ~z
0 1~ ~ O `J ~ 0~ ~ O~J r~ O C~ ~ O C~ ~
o o o o o o o -
r~r~o ~r~o r~o r~oo r~oo
a~
o~ ~ o ~ c~
u~ ~ u
--18--
1334818
1~
., ",
o,
Z " ,'
o,~
P E~
_
- 8-~q C~l
PE~
~ ~-q
c
-
L r
~ r-
_ ~
~ r~ Z
~ U)~
~ OC~
O O -
00
--19--
`- 1334848
Examples 64 and 65
The procedure of Example 2 was repeated except
there was no purging of this reaction vessel with
nitrogen before or during the reaction. To 100 parts of
5 hexamethylene diisocyanate was added 0.4 parts of
triethanolamine. The isocyanate content of the
resulting reaction mixture after being heated at 250G
for 2 minutes was 43.3%. The reaction was repeated
except the reaction vessel was purged with dry nitrogen
10 before and during the reaction to afford an isocyanate
content of 33.7%.
Examples 66 and 67
The procedure of Examples 64 and 65 was
repeated except triethanolamine was replaced by 0.4
15 parts of N-methyldiethanolamine. The resulting % NCO
with no nitrogen purging was 46.0% and with nitrogen
purging was 40.6%.
Examples 68, 69, 70 and 71
To a 2-liter 3-neck flask were added 1000 grams
20 of hexamethylene diisocyanate, 4.0 grams triethanolamine
and 4.0 grams n-butanol. The stirred reaction mixture
was held at 50C for 1 hour, then cooled to ambient
temperature while being purged with dry nitrogen. After
one hour, 100 grams (having a titrated NCO content of
25 48.6% compared to a theoretical NCO of 48.7%) of this
material was heated at 250C for 2 minutes as described
in Example 2 to afford on cooling a clear solution with
an NCO content of 34.6%. After 24 hours another sample
(having an NCO content of 48.6%) was heated at 250C for
30 2 minutes to give an NC0 content of 32.2%. The process
was repeated after 8 and 108 days (initial % NCO
starting mix in both runs was 48.6%) to afford 34.4% and
32.2% NCO, respectively.
-20-
13348~8
Examples 72-92
Using the procedure described in Example 2
above the following trimerization of aromatic
isocyanates were carried out using the specified
5 reagents and conditions set forth in the following
table. MDI is methylene bis(phenylisocyanate).
1334848
~ - O ~ ~ r-- ~ u) ~
~3 t _ ~~ ~ ~o o ~
o ~ ~ ~ ~ ~ ~ ~ ~ ~J
~ ~,
o o o o o o o
t, ~ o o U~ U~ o o o
~ U~
c~ P E~--~
~e~
.~ I r
a ~ a ~ ~ a ~ ~ a
C ~ C ~ ~ C
- I v ~ C _ --
- ~ E ~E ~ ~o ~ ~E
U` ~ I ~ Z
C cn ~ ~ 0
.
o~ oC~ o ~ o ~ o ~ o ~ o
, o. o. o o . o . o . o .
F ~ ~o ~o ~ o ~ o ~ o ~ o _l O
--22--
1334848
o
o o o
Z
~c ,~
r
~3 E~
., o
o o o o o o o o
~ 1 o o n o o o
t~ 3 c~ c~
ca~ E ~
C E~ E ,
C~
a~ E~
.~ .~
1~ r . ' 1--1 (3 ~ , ~ , ~ H ~
u ~ z ~ Z ~ !~ t ~! z
u~ u~ u~ u~ 0 u~ u~u~ u~ u~ u~ u~ u~ u~ cn u~ u~ u~
~ o~ o~ $~ ~ g~ o~ g~ g~
,~oo,~o ,~o ,~o,~o ~oo,~o ,~o
o ,~
--23--
-- 1334848
o I - . . . . . .
o ~ ~ oo oo t-- o ~
~ a
O ~ r
~3 E~
~ C~
o o o o U~ U~
E
U~
~ E~
C~
~ ~a ~
~ E~
~ ~a ~3 3
- Ç
L 1 a ~ ~ IL
r ~ ,~
n~ - a) ~ a.1 c~ -
n H 1; ~1~3 1~ E ~1 ~_ ~ 1~ ~, _
z ~ !~ æ ~ z ~ æ ~ ~ ~r~ ~ rl ~ ~
~ ~ ~ ~ t~ ~ ~ ~ ~ ~ ~ u u U
r-
o ~ ~ o o~ o o~ o oo o c~ ~ o c`~
O ~1 0 ~1 0 r-l O O ~_ O
O ~ C~
--24 ~-
133~848
Example 93
To a 250 ml 3-neck flask were added 100 grams
of hexamethylene diisocyanate, 2.7 grams
1,3-propanediol, and 0.3 grams 1-(2-hydroxyethyl)
5 pyrrolidine. The stirred reaction mixture was heated
over a 5 minute period to 125C. After 3 hours at
125C, the NCO content had dropped to 30.4%. At this
time, 0.022 grams of hydrogen chloride (~210 ppm) was
added. After 0.5 hours at 125C the NCO content was
10 30.4% and after an additional 0.5 hours at 125C, the
NCO content was unchanged from the previous reading.
Example 94 (Compare to 91 and 92)
To a 250 ml 3-neck flask were added 100 grams
of MDI, 1.4 grams 1,3-propanediol and 0.2 grams
15 1-(2-hydroxyethyl) pyrrolidine. The stirred reaction
mixture was heated over a 5 minute period to 125C.
After 2 minutes at 125C, the NCO content was 32.2%. At
this time 0.022 grams of hydrogen chloride (~210 ppm)
was added. After 0.5 hours at 125C the NCO content was
20 31.8% and after an additional 0.5 hours at 125C the NCO
content was unchanged from the previous reading.
Example 95
To a 250 ml 3-neck flask were added 49.1 grams
of hexamethylene diisocyanate, 50.9 grams of 2,4-toluene
25 diisocyanate and 0.2 grams of N-methylethanolamine. The
stirred reaction mixture was heated over a 4 minute
period to 200C. After 10 minutes at 200C, the
reaction mixture was cooled over a 2 minute period to
50C. The resulting clear yellow liquid had a 40.1% NCO
30 content. Using HPLC analysis, the polymeric trimer
product was found to have an aliphatic component of
about 30%.
Although the invention has been described in
detail in the foregoing for the purpose of illustration,
35 it is to be understood that such detail is solely for
-25-
- 1334848
that purpose and that variations can be made therein by
those skilled in the art without departing from the
spirit and scope of the invention except as it may be
limited by the claims.
-26-
