U.S. patent application number 15/712181 was filed with the patent office on 2018-01-11 for process for preparing polycarbamate and reaction product thereof.
The applicant listed for this patent is Dow Global Technologies LLC. Invention is credited to Paul Foley, Yiyong He, John W. Hull, JR., Xinrui Yu.
Application Number | 20180009947 15/712181 |
Document ID | / |
Family ID | 51300906 |
Filed Date | 2018-01-11 |
United States Patent
Application |
20180009947 |
Kind Code |
A1 |
Yu; Xinrui ; et al. |
January 11, 2018 |
PROCESS FOR PREPARING POLYCARBAMATE AND REACTION PRODUCT
THEREOF
Abstract
A first process to produce polycarbamate comprising providing
urea in liquid form; and adding the liquid urea to a polyol is
provided. A second process for producing polycarbamate comprising
adding solid urea to a polyol in liquid form to form a reaction
mixture is provided. Also provided is a reaction product produced
by the first process or second process.
Inventors: |
Yu; Xinrui; (Midland,
MI) ; He; Yiyong; (Midland, MI) ; Hull, JR.;
John W.; (Midland, MI) ; Foley; Paul;
(Traverse City, MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Dow Global Technologies LLC |
Midland |
MI |
US |
|
|
Family ID: |
51300906 |
Appl. No.: |
15/712181 |
Filed: |
September 22, 2017 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
13955507 |
Jul 31, 2013 |
9796815 |
|
|
15712181 |
|
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C08G 71/04 20130101;
C08G 65/33303 20130101 |
International
Class: |
C08G 71/04 20060101
C08G071/04; C08G 65/333 20060101 C08G065/333 |
Claims
1. (canceled)
2. (canceled)
3. (canceled)
4. (canceled)
5. (canceled)
6. (canceled)
7. (canceled)
8. (canceled)
9. (canceled)
10. (canceled)
11. A second process for producing polycarbamate comprising: adding
solid urea to a polyol in liquid form to form a reaction mixture;
wherein the polyol is dissolved in a solvent; and wherein the
polyol is selected from the group consisting of acrylic,
styrene-acrylic, styrene-butadiene, saturated polyester,
polyalkylene polyols, urethane, alkyd, polyether and
polycarbonate.
12. The second process according to claim 11, wherein the
temperature of the reaction mixture is above the melting point of
urea.
13. The second process according to claim 11, wherein the adding
the solid urea to the polyol is conducted in a semi-batch
manner.
14. The second process according to claim 12, wherein the adding
the solid urea to the polyol in liquid form is conducted in the
presence of a catalyst.
15. The second process according to claim 11, wherein the solid
urea is added to the polyol in liquid form at a constant, pulsed,
or variable rate of addition.
16. (canceled)
17. A reaction product produced by the second process according to
claim 11.
Description
FIELD OF INVENTION
[0001] The instant invention relates to a process for preparing
polycarbamate and a reaction product thereof.
BACKGROUND OF THE INVENTION
[0002] Polyurethane is a polymer composed of a chain of organic
units with carbamate linkages. Polyurethanes may be produced using
isocyanate as a starting material. However, trace amounts of
residual isocyanates raise health and safety concerns. As an
alternative, polyurethanes have been produced using polyols and
methyl carbamate as the starting materials. Methyl carbamate,
however, also gives rise to health and safety concerns. There
remains a need for alternative polyurethane production methods
which provide polyurethanes useful in a variety of applications
while minimizing health and safety concerns.
SUMMARY OF THE INVENTION
[0003] The instant invention is a process for preparing a
polycarbamate and a reaction product thereof.
[0004] In one embodiment, the instant invention provides a first
process to produce polycarbamate comprising: providing urea in
liquid form; and adding the liquid urea to a polyol. In an
alternative embodiment, the instant invention provides a second
process to produce polycarbamate comprising: adding solid urea to a
polyol in liquid form to form a reaction mixture.
DETAILED DESCRIPTION OF THE INVENTION
[0005] The instant invention is a process for preparing a
polycarbamate and a reaction product thereof.
First Process
[0006] The first process according to the present invention
comprises providing urea in liquid form; and adding the liquid urea
to a polyol.
Urea
[0007] The liquid form of the urea (or "liquid urea") may be
achieved in any acceptable manner. For example, the urea may be
dissolved in a first solvent. Alternatively, the urea may be
melted. In yet another alternative, the urea may be suspended in a
clathrate. A urea clathrate may also be known as a urea inclusion
compound and may have the structure as described in "Supramolecular
Chemistry" John Wiley & Sons, Jonathan w. Steed, Jerry L.
Atwood, pp. 393-398 and Harris, K. D. M., "Fundamental and Applied
Aspects of Urea and Thiourea Inclusion Compounds", Supramol. Chem.
2007, 19, 47-53.
[0008] The liquid form of the urea may alternatively be present in
a combination of liquid forms.
[0009] In a particular embodiment, the urea is dissolved in water.
In another embodiment, the urea may be dissolved in a mixture of
two or more first solvents. Such first solvents include organic
solvents. In an alternative embodiment, the urea is dissolved in
one or more first solvents selected from water and organic
alcohols. In one embodiment, urea is partially soluble in the first
solvent or mixture of first solvents. In yet another embodiment,
urea is fully soluble in the first solvent or mixture of first
solvents.
Polyol
[0010] As used herein, the term "polyol" means an organic molecule
having at least 2 --OH functionalities. As used herein, the term
"polyester polyol" means a subclass of polyol that is an organic
molecule having at least 2 alcohol (--OH) groups and at least one
carboxylic ester (CO.sub.2--C) functionality. The term "alkyd"
means a subclass of polyester polyol that is a fatty acid-modified
polyester polyol wherein at least one carboxylic ester
functionality is preferably derived from an esterification reaction
between an alcoholic --OH of the polyol and a carboxyl of a
(C.sub.8-C.sub.60) fatty acid. The polyol may be any polyol; for
example, the polyol may be selected from the group consisting of
acrylic, styrene-acrylic, styrene-butadiene, saturated polyester,
polyalkylene polyols, urethane, alkyd, polyether or polycarbonate.
In one exemplary embodiment, the polyol component comprises
hydroxyethyl acrylate. In another exemplary embodiment, the polyol
component comprises hydroxyethyl methacrylate.
[0011] The reaction mixture may comprise from 10 to 100 percent by
weight of polyol; for example, from 30 to 70 percent by weight of
polyol. In one embodiment, the polyol has a functional structure of
a 1,2-diol, 1,3-diol, or combinations thereof.
[0012] The polyol can be non-cyclic, straight or branched; cyclic
and nonaromatic; cyclic and aromatic, or a combination thereof. In
some embodiments the polyol comprises one or more non-cyclic,
straight or branched polyols. For example, the polyol may consist
essentially of one or more non-cyclic, straight or branched
polyols.
[0013] In one embodiment, the polyol consists essentially of
carbon, hydrogen, and oxygen atoms. In another embodiment, the
polyol consists of primary hydroxyl groups. In yet another
embodiment, the hydroxyl groups are in the 1,2 and/or 1,3
configuration. Exemplary polyol structures are shown below for
illustrative purposes.
##STR00001##
[0014] Polyol useful in embodiments of the inventive process
include oligomers or polymers derived from hydroxy-containing
acrylic monomeric units. Suitable monomers may be, but are not
limited to, hydroxyethyl acrylate, hydroxypropyl acrylate,
hydroxybutyl acrylate, hydroxydodecyl acrylate, hydroxyethyl
methacrylate, hydroxypropyl methacrylate, hydroxybutyl
methacrylate, hydroxydodecyl methacrylate, hydroxybutyl vinyl
ether, diethylene glycol vinyl ether and a combinations thereof.
The polyol useful in embodiments may be prepared by reacting at
least one hydroxyl-containing monomer with one or more monomers.
Suitable monomers may be, but are not limited to, vinyl monomers
such as styrene, vinyl ether, such as ethyl vinyl ether, butyl
vinyl ether, cyclohexyl vinyl ether, ester of unsaturated carbonic
acid and dicarbonic acid, such as methyl acrylate, methyl
methacrylate, ethyl acrylate, ethyl methacrylate, 2-ethylhexyl
acrylate, 2-ethylhexyl methacrylate, dodecyl acrylate, dodecyl
methacrylate, dimethyl maleate and a mixture thereof.
[0015] Polyols useful in certain embodiments of the inventive
process include polyether polyols and polyester polyols. Suitable
polyols include, for example, ethylene glycol, diethylene glycol,
neopentyl glycol, 1,4-butanediol, 1,6-hexanediol, glycerol,
pentaerythritol, sorbitol and mannitol. Suitable glycols thus
include ethylene glycol, propylene glycol, diethylene glycol,
triethylene glycol, tetraethylene glycol, pentaethylene glycol,
hexaethylene glycol, heptaethylene glycol, octaethylene glycol,
nonaethylene glycol, decaethylene glycol, neopentyl glycol,
glycerol, 1,3-propanediol, 2,4-dimethyl-2-ethyl-hexane-1,3-diol,
2,2-dimethyl-1,2-propanediol, 2-ethyl-2-butyl-1,3-propanediol,
2-ethyl-2-isobutyl-1,3-propanediol, 1,3-butanediol, 1,4-butanediol,
1,5-pentanediol, 1,6-hexanediol, 2,2,4-tetramethyl-1,6-hexanediol,
thiodiethanol, 1,2-cyclohexanedimethanol,
1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol,
2,2,4-trimethyl-1,3-pentanediol,
2,2,4-tetramethyl-1,3-cyclobutanediol, p-xylenediol, hydroxypivalyl
hydroxypivalate, 1,10-decanediol, hydrogenated bisphenol A,
trimethylolpropane, trimethylolethane, pentaerythritol, erythritol,
threitol, dipentaerythritol, sorbitol, mannitol, glycerine,
dimethylolpropionic acid, and the like.
[0016] Polycarboxylic acids useful in the invention may include,
but are not limited to, phthalic anhydride or acid, maleic
anhydride or acid, fumaric acid, isophthalic acid, succinic
anhydride or acid, adipic acid, azeleic acid, and sebacic acid,
terephthalic acid, tetrachlorophthalic anhydride,
tetrahydrophthalic anhydride, dodecanedioic acid, sebacic acid,
azelaic acid, 1,4-cyclohexanedicarboxylic acid,
1,3-cyclohexanedicarboxylic acid, 2,6-naphthalenedicarboxylic acid,
glutaric acid, trimellitic anhydride or acid, citric acid,
pyromellitic dianhydride or acid, trimesic acid, sodium
sulfoisophthalic acid, as well as from anhydrides of such acids,
and esters thereof, where they exist. Optionally monocarboxylic
acids may be employed including, but not limited to, benzoic acid.
The reaction mixture for producing alkyds includes one or more
aliphatic or aromatic polycarboxylic acids, esterified
polymerization products thereof, and combinations thereof. As used
herein, the term "polycarboxylic acid" includes both polycarboxylic
acids and anhydrides thereof. Examples of suitable polycarboxylic
acids for use in the present invention include phthalic acid,
isophthalic acid, terephthalic acid, tetrahydrophthalic acid,
naphthalene dicarboxylic acid, and anhydrides and combinations
thereof.
Addition Step
[0017] In a certain embodiment of the first process, the adding the
urea in liquid form to the polyol is conducted in the presence of a
catalyst. Suitable catalysts for use in this process include, but
are not limited to, organo-tin compounds. The use of this type of
catalyst is well known in the art. Examples of catalysts useful in
the present invention include, but are not limited to, dibutyltin
diacetate, and dibutyltin oxide. In a particular embodiment, the
catalyst is used in an amount from 0.1% to 1.0 wt % based on polyol
weight. All individual values and subranges from 0.1 to 1.0 wt %
are included herein and disclosed herein; for example, the catalyst
amount may range from a lower limit of 0.1, 0.2, 0.4, 0.6 or 0.8 wt
% based on polyol weight to an upper limit of 0.15, 0.3, 0.5, 0.7,
0.9 or 1.0 wt % based on polyol weight. For example, the catalyst
amount, in certain embodiments, may be from 0.1 to 1.0 wt % based
on polyol weight, or in the alternative, from 0.5 to 1.0 wt % based
on polyol weight, or in the alternative, from 0.1 to 0.6 wt % based
on polyol weight.
[0018] The adding the urea in liquid form to polyol may be
accomplished by any means. In a particular embodiment of the first
process, the adding the urea in liquid form to the polyol is
conducted in a batch manner. In a particular embodiment of the
first process, the adding the urea in liquid form to the polyol is
conducted in a semi-batch manner. In one embodiment, the urea in
liquid form is added at a constant rate over a period of time in
which the reaction proceeds. In yet another embodiment, the urea in
liquid form is added to the polyol at more than one rate, with the
rate changing over the time period in which the reaction proceeds.
In yet another embodiment, the urea in liquid form is added to the
polyol using a pulsed constant rate in which the urea is added at a
rate for a first period of time, followed by a second period of no
urea addition, followed by urea addition at the same rate for a
third period of time, and so on. In another alternative embodiment,
the urea in liquid form is added to the polyol using a pulsed
variable rate in which the urea is added at a first rate for a
first period of time, followed by a second period of no urea
addition, followed by urea addition at a second rate for a third
period of time, and so on.
[0019] In one embodiment of the first process, the polyol is
complete polyol in the absence of any solvent. In an alternative
embodiment of the first process, the polyol is dissolved in a
second solvent prior to the adding the liquid urea to the dissolved
polyol. The second solvent may be any solvent or mixture of
solvents in which the polyol is soluble or partially soluble. In
certain embodiments, the first and second solvents form a
heterogeneous azeotrope allowing removal of the first solvent by
decantation or other means. In certain embodiments, removal of the
first solvent from a heterogenous azeotrope permits concurrent
removal of certain by-products, such as ammonia, which are soluble
in the first solvent. In yet an alternative embodiment, the first
and second solvents form a heterogeneous azeotrope allowing removal
of the first solvent and further wherein the second solvent is
returned to the reactor.
[0020] In certain embodiments, the first process achieves at least
a 50% conversion of hydroxyl groups of the polyol. All individual
values and subranges from at least 50% conversion are included
herein and disclosed herein; for example, the hydroxyl conversion
may range from a lower limit of 50%, or in the alternative, the
hydroxyl conversion may range from a lower limit of 55%, or in the
alternative, the hydroxyl conversion may range from a lower limit
of 60%, or in the alternative, the hydroxyl conversion may range
from a lower limit of 65%, or in the alternative, the hydroxyl
conversion may range from a lower limit of 70%, or in the
alternative, the hydroxyl conversion may range from a lower limit
of 75% or in the alternative, the hydroxyl conversion may range
from a lower limit of 80%, or in the alternative, the hydroxyl
conversion may range from a lower limit of 85%.
Reaction Product of First Process
[0021] In another alternative embodiment, the instant invention
provides a reaction product of any of the embodiments of the first
process disclosed herein.
[0022] In one embodiment, the reaction product of the first process
exhibits a Gardner color of less than or equal to 2. All individual
values and subranges are included herein and disclosed herein; for
example, the Gardner color index may be from an upper limit of 2 or
1.
[0023] In one embodiment, the reaction product of the second
process exhibits a Gardner color of less than or equal to 2. All
individual values and subranges are included herein and disclosed
herein; for example, the Gardner color index may be from an upper
limit of 2 or 1.
[0024] In specific embodiments, a 100% solids reaction product of
the first process comprises less than 0.2 wt % cyanuric acid. All
individual values and subranges from less than 0.2 wt % are
included herein and disclosed herein. For example, the amount of
cyanuric acid may be less than 0.2 wt %, or in the alternative,
less than 0.1 wt %, or in the alternative, less than 0.09 wt %, or
in the alternative, less than 0.07 wt %, or in the alternative,
less than 0.04 wt %, or in the alternative, less than 0.02 wt %. In
a particular embodiment, the amount of cyanuric acid present in a
100% solids reaction product is from 0.05 to 0.15 wt %, or in the
alternative, from 0.1 to 0.2 wt %.
[0025] In specific embodiments, a 100% solids reaction product of
the first process comprises less than 0.6 wt % biuret. All
individual values and subranges from less than 0.6 wt % are
included herein and disclosed herein. For example, the amount of
biuret may be less than 0.6 wt %, or in the alternative, less than
0.55 wt %, or in the alternative, less than 0.52 wt %, or in the
alternative, less than 0.4 wt %, or in the alternative, less than
0.36 wt %, or in the alternative, less than 0.1 wt %. In a
particular embodiment, the amount of biuret present in a 100%
solids reaction product of the first process is from 0.35 to 0.6 wt
%, or in the alternative, from 0.4 to 0.6 wt %, or in the
alternative, from 0.01 to 0.1 wt %.
[0026] In specific embodiments, a 100% solids reaction product of
the first process comprises less than 2 wt % polyallophanate. All
individual values and subranges from less than 2 wt % are included
herein and disclosed herein. For example, the amount of
polyallophanate present in a 100% solids reaction product is less
than 2 wt %, or in the alternative, less than 1.8 wt %, or in the
alternative, less than 1.0 wt %, or in the alternative, less than
0.6 wt %, or in the alternative, less than 0.3 wt %, or in the
alternative, less than 0.1 wt %. In a particular embodiment, the
amount of polyallophanate present in a 100% solids reaction product
of the first process is from 0.3 to 2 wt %, or in the alternative,
from 0.55 to 0.15 wt %., or in the alternative, from 0.01 to 0.05
wt %.
Second Process
[0027] In an alternative embodiment, the instant invention further
provides a second process for producing polycarbamate comprising
adding solid urea to a polyol in liquid form to form a reaction
mixture.
[0028] Polyols suitable for use in the second process are identical
to those discussed in connection with the first process. The liquid
form of the polyol may arise from any means, such as, by
dissolution in a solvent, a non-dissolved yet liquid polyol or by
melting.
[0029] In one specific embodiment, the temperature of the reaction
mixture is above the melting point of urea.
[0030] In one embodiment of the second process, the adding the
solid urea is conducted in a batch manner. In yet another
embodiment of the second process, the adding the solid urea to the
polyol is conducted in a semi-batch manner. In one embodiment, the
urea is added at a constant rate over a period of time in which the
reaction proceeds. In yet another embodiment, the urea is added to
the polyol at more than one rate, with the rate changing over the
time period in which the reaction proceeds. In yet another
embodiment, the urea is added to the polyol using a pulsed constant
rate in which the urea is added at a rate for a first period of
time, followed by a second period of no urea addition, followed by
urea addition at the same rate for a third period of time, and so
on. In another alternative embodiment, the urea is added to the
polyol using a pulsed variable rate in which the urea is added at a
first rate for a first period of time, followed by a second period
of no urea addition, followed by urea addition at a second rate for
a third period of time, and so on.
[0031] In a certain embodiment of the second process, the adding
the urea to the polyol is conducted in the presence of a catalyst.
Suitable catalysts for use in this process include, but are not
limited to, organo-tin compounds. The use of this type of catalyst
is well known in the art. Examples of catalysts useful in the
present invention include, but are not limited to, dibutyltin
diacetate, and dibutyltin oxide. In a particular embodiment, the
catalyst is used in an amount from 0.1% to 1.0 wt % based on polyol
weight. All individual values and subranges from 0.1 to 1.0 wt %
are included herein and disclosed herein; for example, the catalyst
amount may range from a lower limit of 0.1, 0.2, 0.4, 0.6 or 0.8 wt
% to an upper limit of 0.15, 0.3, 0.5, 0.7, 0.9 or 1.0 wt %. For
example, the catalyst amount, in certain embodiments, may be from
0.1 to 1.0 wt %, or in the alternative, from 0.5 to 1.0 wt %, or in
the alternative, from 0.1 to 0.6 wt %.
[0032] In another alternative embodiment, the instant invention
provides a reaction product of any of the embodiments of the second
process disclosed herein.
[0033] In one embodiment, the reaction product of the second
process exhibits a Gardner color of less than or equal to 2. All
individual values and subranges are included herein and disclosed
herein; for example, the Gardner color index may be from an upper
limit of 2 or 1.
[0034] In specific embodiments, a 100% solids reaction product of
the second process comprises less than 0.2 wt % cyanuric acid. All
individual values and subranges from less than 0.2 wt % are
included herein and disclosed herein. For example, the amount of
cyanuric acid present in the 100% solids reaction product is less
than 0.2 wt %, or in the alternative, less than 0.1 wt %, or in the
alternative, less than 0.09 wt %, or in the alternative, less than
0.07 wt %, or in the alternative, less than 0.04 wt %, or in the
alternative, less than 0.02 wt %. In a particular embodiment, the
amount of cyanuric acid present in the 100% solids reaction product
is from 0.01 to 0.2 wt %, or in the alternative, from 0.1 to 0.2 wt
%.
[0035] In specific embodiments, a 100% solids reaction product of
the second process comprises less than 0.6 wt % biuret. All
individual values and subranges from less than 0.6 wt % are
included herein and disclosed herein. For example, the amount of
biuret present in the 100% solids reaction product is less than 0.6
wt %, or in the alternative, less than 0.55 wt %, or in the
alternative, less than 0.52 wt %, or in the alternative, less than
0.4 wt %, or in the alternative, less than 0.36 wt %. In a
particular embodiment, the amount of biuret present in the 100%
solids reaction product of the second process is from 0.35 to 0.4
wt %, or in the alternative, from 0.35 to 0.38 wt %.
[0036] In specific embodiments, a 100% solids reaction product of
the second process comprises less than 2 wt % polyallophanate. All
individual values and subranges from less than 2 wt % are included
herein and disclosed herein. For example, the amount of
polyallophanate present in the 100% solids reaction product is less
than 2 wt %, or in the alternative, less than 1.8 wt %, or in the
alternative, less than 1.0 wt %, or in the alternative, less than
0.6 wt %, or in the alternative, less than 0.3 wt %. In a
particular embodiment, the amount of polyallophanate present in the
100% solids reaction product of the second process is from 0.25 to
1.2 wt %, or in the alternative, from 0.26 to 0.75 wt %.
EXAMPLES
[0037] The following examples illustrate the present invention but
are not intended to limit the scope of the invention.
Example 1--Batch Process to Produce Polycarbamate from Reaction of
Urea and Polyol
[0038] A 1-L reactor with heating mantle was used in the reaction.
The reactor was equipped with an agitator, a thermal-couple and a
nitrogen sparger. A water-cooled condenser was connected to the
adaptor on the reactor lid. The overhead condensate was collected
by a receiver and the non-condensable went through a bubbler filled
with mineral oil and then entered a 1-L scrubber filled with
water.
[0039] 850 g PARALOID.TM. AU-608X polyol which consists of 58%
solid and 42% solvent (xylenes) was added to the reactor. PARALOID
AU-608X is an acrylic polyol which is commercially available from
The Dow Chemical Company. The polyol used in Inventive Example 1
has 0.76 mol hydroxyl functionality. 5.20 g dibutyltin oxide (98%
pure) was added to the reactor. 45.87 g 99% pure urea was used in
this reaction. The heating mantle was started and set at
158.degree. C. The nitrogen sparging flow rate was set at 20 sccm.
The reaction mixture was agitated at 100 rpm and then adjusted to
400 rpm when the reactor temperature was over 60.degree. C. Urea
was added to the reactor when the reactor temperature was over
130.degree. C. The reaction was carried out at 138-142.degree. C.
for 12 hours. After the reaction was complete, the heating mantle
was shut down and the agitation rate was reduced to 60 rpm. When
the reactor temperature dropped to 60.degree. C., the polycarbamate
product was poured out from the reactor. The final product was
analyzed using .sup.13C NMR. 800.6 g polycarbamate with hydroxyl
conversion of 82.3% was obtained. The starting polyol was clear and
colorless. The polycarbamate product had a Gardner color of 3 and
further contained solid particles. By microscopic examination, the
solid particles were amorphous in shape and had a size ranging from
5 to 60 .mu.m across the largest dimension. By-product
concentration was measured based upon the 100% solids product
weight. Table 1 provides the results of by product testing.
TABLE-US-00001 TABLE 1 Biuret + Cyanuric Biuret (wt % in Cyanuric
Acid Polyallophanate acid + polyallophate 100% solids (wt % in 100%
(wt % in p100% (wt % in 100% product) solids product) solids
product) solids product) 0.47% 0.10% 1.70% 2.27%
Example 2--Semi-Batch Process to Produce Polycarbamate from Solid
Urea and Polyol
[0040] A 1-L reactor with heating mantle was used in this reaction.
The reactor had a glass agitator at the center neck on the lid and
a nitrogen sparger to the bottom of the reactor. The reactor
temperature was measured using a thermal couple. A water-cooled
condenser was connected to the adaptor on the reactor lid. The
overhead condensate was collected by a receiver and the
non-condensable went through a bubbler filled with mineral oil and
then entered a 1-L scrubber filled with water.
[0041] 929.35 g polyol PARALOID.TM. AU-608X which consists of 58%
solid and 42% solvent (xylenes) was added to the reactor, which had
0.83 mol hydroxyl functionality. 5.69 g dibutyltin oxide (98% pure)
was added to the reactor. 52.9 g 99% pure urea was used for this
reaction. The heating mantle was started and set at 158.degree. C.
The nitrogen sparging flow rate was set at 20 sccm. The reaction
mixture was agitated at 100 rpm and then adjusted to 400 rpm when
the reactor temperature was over 60.degree. C.
[0042] Urea was added to the reactor using a semi-batch method.
When the reactor temperature was over 130.degree. C., 60% of the
total urea (31.7 g) was added to the reactor. The reaction was
carried out at 138-142.degree. C. The rest 40% of total urea (21.2
g) was added into the reactor in 4 equal portions (10% of the total
urea each portion, 5.02 g) at 5 hrs, 9.5 hrs, 13.5 hrs and 16.5
hrs. The total reaction time was 20 hours. After the reaction was
complete, the heating mantle was shut down and the agitation rate
was reduced to 60 rpm. When the reactor temperature dropped to
60.degree. C., the polycarbamate product was poured out from the
reactor. The final product was analyzed using .sup.13C NMR. 915.0 g
polycarbamate with hydroxyl conversion of 85.6% was obtained.
[0043] The starting polyol was clear and colorless. The
polycarbamate product had a Gardner color of 2 and no solid
particles were detected visually or by microscopic examination.
By-product concentrations were measured based upon the 100% solids
polycarbamate product weight. Table 2 provides the results of by
product testing.
TABLE-US-00002 TABLE 2 Biuret + Cyanuric Biuret (wt % in Cyanuric
Acid Polyallophanate acid + polyallophate 100% solids (wt % in 100%
(wt % in 100% (wt % in 100% product) solids product) solids
product) solids product) 0.35% 0.01% 0.26% 0.62%
Example 3 Semi-Batch Process to Produce Polycarbamate from Aqueous
Urea Solution and Polyol
[0044] A 1-L reactor with heating mantle was used in this reaction.
The reactor had a glass agitator at the center neck on the lid and
a nitrogen sparger to the bottom of the reactor. The reactor
temperature was measured using a thermal couple. A water-cooled
condenser was connected to the adaptor on the reactor lid. The
overhead condensate was collected by a receiver and the
non-condensable went through a bubbler filled with mineral oil and
then entered a 1-L scrubber filled with water. A syringe pump with
accurate feeding rate was used for urea aqueous solution feeding.
Another syringe pump was used for solvent recycling.
[0045] 800.1 g polyol PARALOID.TM. AU-608X which consists of 58%
solid and 42% solvent (xylenes) was added to the reactor, which had
0.71 mol hydroxyl functionality. 4.90 g dibutyltin oxide (98% pure)
was added to the reactor. 100.0 g xylenes was added to the reactor
to keep a low viscosity for the reaction. The heating mantle was
started and set at 158.degree. C. The nitrogen sparging flow rate
was set at 20 sccm. The reaction mixture was agitated at 100 rpm
and then adjusted to 400 rpm when the reactor temperature was over
60.degree. C.
[0046] 43.17 g 99% pure urea was dissolved in 40.0 g deionized
water to form a urea aqueous solution. The solution was charged
into a syringe. When the reactor temperature reached 140.degree.
C., the syringe pump was started at 2 ml/min for a period of 10
minutes 51 seconds, during which 30% of total urea solution (21.7
ml) was fed into the reactor. The pump feeding was stopped. When
the reaction time reached 3 hrs 10 minutes, the pump feeding was
started at 40 ml/hr for approximate 38 minutes to add 35% urea
solution (25.3 ml) to the reactor. The pump was then stopped. When
the reaction time reached 8 hrs, the pump feeding was started at 5
ml/hr for the rest 35% urea solution (25.3 ml). At reaction time of
13 hrs, urea solution feed was complete. During urea aqueous
solution feeding, an azeotrope of water and xylenes was collected
in the overhead receiver. The overhead liquid was collected and
separated every hour from the receiver. The xylenes phase was
rinsed with equal mass of deionized water and pumped back to the
reactor.
[0047] The total reaction time was 17 hours. After the reaction was
complete, the heating mantle was shut down and the agitation rate
was reduced to 60 rpm. When the reactor temperature dropped to
60.degree. C., the polycarbamate product was poured out from the
reactor. The final product was analyzed using .sup.13C NMR. 804 g
polycarbamate with hydroxyl conversion of 80.4% was obtained.
[0048] The starting polyol was clear and colorless. The
polycarbamate product had a Gardner color of less than or equal to
1 and no solid particles were detected visually or by microscopic
examination. By-product concentrations were measured based upon the
100% solids polycarbamate product weight. Table 3 provides the
results of by product testing.
TABLE-US-00003 TABLE 3 Biuret + Cyanuric Biuret (wt % in Cyanuric
Acid Polyallophanate acid + polyallophate 100% solids (wt % in 100%
(wt % in 100% (wt % in 100% product) solid product) solids product)
solids product) 0.05% 0.01% 0.03% 0.09%
Test Methods
[0049] Test methods include the following:
OH Number Titration
[0050] Where OH number is the magnitude of the hydroxyl number for
a polyol as expressed in terms of milligrams potassium hydroxide
per gram of polyol (mg KOH/g polyol). Hydroxyl number (OH #)
indicates the concentration of hydroxyl moieties in a composition
of polymers, particularly polyols. The hydroxyl number for a sample
of polymers is determined by first titrating for the acid groups to
obtain an acid number (mg KOH/g polyol) and secondly, acetylation
with pyridine and acetic anhydride in which the result is obtained
as a difference between two titrations with potassium hydroxide
solution, one titration with a blank for reference and one
titration with the sample. A hydroxyl number is the weight of
potassium hydroxide in milligrams that will neutralize the acetic
anhydride capable of combining by acetylation with one gram of a
polyol plus the acid number from the acid titration in terms of the
weight of potassium hydroxide in milligrams that will neutralize
the acid groups in the polyol. A higher hydroxyl number indicates a
higher concentration of hydroxyl moieties within a composition. A
description of how to determine a hydroxyl number for a composition
is well-known in the art, for example in Woods, G., The ICI
Polyurethanes Book, 2.sup.nd ed. (ICI Polyurethanes, Netherlands,
1990).
[0051] Gardner Color:
[0052] was measured according to ASTM D1544 "Standard Test Method
for Color of Transparent Liquids (Gardner Color Scale)" using a
HunterLab colorimeter.
[0053] .sup.13C NMR:
[0054] All samples were characterized by .sup.13C NMR in solutions.
For a typical sample preparation, 0.6 g dry material was dissolved
in 2.5 mL DMSO-d.sub.6 solvent at room temperature in a glass vial.
The DMSO-d.sub.6 solvent contains 0.015 M Cr(acac).sub.3 as a
relaxation agent. The solution was then transferred to a 10 mm NMR
tube for characterization. Quantitative inverse-gated .sup.13C NMR
experiments were performed on a Bruker Avance 400 MHz (.sup.1H
frequency) NMR spectrometer equipped with a 10 mm DUAL C/H
cryoprobe. All experiments were carried out without sample spinning
at 25.0.degree. C. Calibrated 90.degree. pulse was applied in the
inverse-gated pulse sequence. The relaxation delay between
consecutive data acquisitions is 5*T.sub.1, where T.sub.1 is the
longest spin-lattice relaxation time of all nuclei in the measured
system. The .sup.13C NMR spectra were processed with a line
broadening of 1 Hz, and referenced to 39.5 ppm for the DMSO-d.sub.6
resonance peak.
[0055] Information that can be obtained from .sup.13C NMR spectra
includes the percent of hydroxyl conversion, byproduct levels and
solid content of the reaction product. The carbon next to a
hydroxyl group has a chemical shift change after the carbamylation
reaction. The hydroxyl conversion was calculated from the peak
intensity ratio of the carbon after and before a carbamylation
reaction. In a quantitative .sup.13C NMR spectrum, each component
of the measured system has a unique resonance peak, and its peak
intensity is proportional to the molar concentration of that
species. The byproduct levels and solid content were calculated by
integrating the desired peaks. The molar concentration can be
converted to weight percentage if the molecular weights for all
species are known. In calculating the solid content, any components
other than known solvents are classified as solid.
[0056] The present invention may be embodied in other forms without
departing from the spirit and the essential attributes thereof,
and, accordingly, reference should be made to the appended claims,
rather than to the foregoing specification, as indicating the scope
of the invention.
* * * * *