Process to produce polycarbamate using a gradient feed of urea

Patent metadata

Field	Value
Publication number	US-9683082-B2
Application number	US-201414908843-A
Country	US
Kind code	B2
Filing date	Jul 28, 2014
Priority date	Jul 31, 2013
Publication date	Jun 20, 2017
Grant date	Jun 20, 2017

Abstract

A process to produce polycarbamate comprising providing urea in liquid form; and adding the urea in liquid form to a polyol in a reduced gradient profile to form polycarbamate product is provided. Also provided are: (a) a reaction product of the process and (b) an apparatus for operating the process.

First claim

The invention claimed is:

1. An article comprising a polycarbamate obtained by a process comprising:
providing urea in liquid form;
adding the urea in liquid form to a polyol in a reduced gradient profile to form polycarbamate product;
wherein the polycarbamate product comprises less than or equal to 0.1 wt % cyanuric acid.

2. The article according to claim 1 , wherein the urea in liquid form is urea dissolved in a solvent.

3. The article according to claim 2 , wherein the solvent is water.

4. The article according to claim 1 , wherein the urea feeding rate is dynamically updated according to the following:

C
u

≈

constant
⁢

⁢
during
⁢

⁢
feeding
⁢

⁢
time

;

F
u

⁡

(
t
)

·

ρ
soln

·

Conc
⁡

(
urea
)

/

M
urea

V
r

=

α
·

C
OH

=

α
·

C
OH
0

⁢

ⅇ

-

kC
u

⁢
t

⁢

⁢
and

⁢

∫
0

t
f

⁢

F
u

⁡

(
t
)

⁢

⁢

ⅆ
t

=

V
u

,

wherein t f =urea solution feeding time; C u =concentration of urea in reactor during feeding, C u ≦ solubility of urea in the reaction system; F u (t)=urea solution feeding rate; ρ soln =urea solution density; M urea =urea molecular weight; Conc(urea)=concentration of urea in the feeding stream; C OH =hydroxyl molar concentration; C OH 0 =initial hydroxyl molar concentration; k=reaction rate coefficient of the desired reaction; α=proportional coefficient of OH concentration and feeding rate; V r =total reactant mixture volume in reactor and V u =total urea solution volume.

5. The article according to claim 4 , wherein hydroxyl molar concentration, C OH is determined by measurement.

6. The article according to claim 5 , wherein the adding the urea in liquid form to a polyol occurs in a reactor and measurement is conducted in the reactor or by sampling from the reactor followed by analysis external to the reactor.

7. The article according to claim 4 , wherein the reactor volume, Vr, is measured.

8. The article according to claim 4 , wherein the hydroxyl molar concentration, C OH is determined by kinetic modeling.

9. The article according to claim 8 , wherein the kinetic modeling is based upon

F
u

⁡

(
t
)

=

α
·

C
OH
0

⁢

ⅇ

-

kC
u

⁢
t

·

V
r

·

M
urea

ρ
soln

·

conc
⁡

(
urea
)

.

Assignees

• Dow Global Technologies Llc

Inventors

• Yu Xinrui
• He Yiyong
• Leng Ronald H

Classifications

• B01J19/24

  Stationary reactors without moving elements inside (B01J19/08, B01J19/26 take precedence; with stationary particles B01J8/02) · CPC title

• C08G71/04 Primary

  Polyurethanes · CPC title

• C09D161/24

  with urea or thiourea · CPC title

• B01J2219/24

  Stationary reactors without moving elements inside · CPC title

• C09D175/12

  from compounds containing nitrogen and active hydrogen, the nitrogen atom not being part of an isocyanate group · CPC title