U.S. patent application number 09/861044 was filed with the patent office on 2001-12-20 for continuous, solvent-free process for making copolymers of maleic anhydride and c1-4 alkyl vinyl ether.
This patent application is currently assigned to ISP INVESTMENTS INC.. Invention is credited to Biss, Russell, Cohen, Jeffrey, Lynn, Jeffrey A., Plochocka, Krystyna, Zamora, John.
Application Number | 20010053829 09/861044 |
Document ID | / |
Family ID | 24386759 |
Filed Date | 2001-12-20 |
United States Patent
Application |
20010053829 |
Kind Code |
A1 |
Biss, Russell ; et
al. |
December 20, 2001 |
Continuous, solvent-free process for making copolymers of maleic
anhydride and C1-4 alkyl vinyl ether
Abstract
A continuous, solvent-free process for obtaining solvent-free,
fine white powders of high molecular weight alternating copolymers
of maleic anhydride and a C.sub.1-C.sub.4 alkyl vinyl ether,
without odor or taste, having the molecular structure (A-B).sub.n,
where A is maleic anhydride, B is an alkyl vinyl ether and n is an
integer indicative of the molecular weight of the copolymer, which
comprises feeding alkyl vinyl ether as reactant and solvent in
excess over the desired 1:1 mole ratio of A:B in the copolymer,
molten maleic anhydride and a free radical initiator, continuously
at predetermined feeding rates into a reactor heated at a reaction
temperature of about 50.degree. to 100.degree. C., charging the
reactor and withdrawing reaction product, residual alkyl vinyl
ether and initiator from the reactor at the same rate as the feed
rate of reactants into the reactor simultaneously thereby
maintaining a constant volume in the reactor, stripping residual
alkyl vinyl ether from the reaction product, drying the copolymer
obtained of any remaining traces of alkyl vinyl ether, and
recycling recovered alkyl vinyl ether back into reactor as reactant
and solvent.
Inventors: |
Biss, Russell; (Wayne,
NJ) ; Cohen, Jeffrey; (Fair Lawn, NJ) ;
Zamora, John; (Paramus, NJ) ; Plochocka,
Krystyna; (Scotch Plains, NJ) ; Lynn, Jeffrey A.;
(West Milford, NJ) |
Correspondence
Address: |
Att: William J. Davis, Esq.
INTERNATIONAL SPECIALTY PRODUCTS
Legal Department, Building No. 10
1361 Alps Road
Wayne
NJ
07470
US
|
Assignee: |
ISP INVESTMENTS INC.
|
Family ID: |
24386759 |
Appl. No.: |
09/861044 |
Filed: |
May 18, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09861044 |
May 18, 2001 |
|
|
|
09596297 |
Jun 15, 2000 |
|
|
|
Current U.S.
Class: |
526/68 ; 526/266;
526/270; 526/271; 526/70 |
Current CPC
Class: |
C08F 2/02 20130101; Y02P
20/582 20151101; C08F 216/18 20130101; C08F 222/06 20130101 |
Class at
Publication: |
526/68 ; 526/70;
526/266; 526/270; 526/271 |
International
Class: |
C08F 002/00 |
Claims
What is claimed is:
1. A continuous, solvent-free process for obtaining solvent-free,
fine white powders of high molecular weight alternating copolymers
of maleic anhydride and a C.sub.1-C.sub.4 alkyl vinyl ether,
without odor or taste, having the molecular structure (A-B).sub.n,
where A is maleic anhydride, B is an alkyl vinyl ether and n is an
integer indicative of the molecular weight of the copolymer, which
comprises feeding alkyl vinyl ether as reactant and solvent in
excess over the desired 1:1 mole ratio of A:B in the copolymer,
molten maleic anhydride and a free radical initiator, continuously
at a predetermined feeding rate into a reactor heated to a reaction
temperature of about 50.degree. to 100.degree. C., charging the
reactor and withdrawing reaction product, residual alkyl vinyl
ether and initiator from the reactor at the same rate as the feed
rate of reactants into the reactor, simultaneously, thereby
maintaining a constant volume in the reactor, stripping residual
alkyl vinyl ether from the reaction product, drying the copolymer
there-obtained of any remaining traces of alkyl vinyl ether, and
recycling recovered alkyl vinyl ether back into reactor as reactant
and solvent, wherein the mole ratio of alkyl vinyl ether to molten
maleic anhydride is about 25:1 to 5:1, wherein the initiator
concentration is 0.01 to 0.2% based on copolymer, wherein the %
copolymer solids in the reaction product removed from the
polymerization reactor is about 10 to 40%.
2. A continuous, solvent-free process according to claim 1 wherein
said alkyl vinyl ether is methyl vinyl ether.
3. A continuous, solvent-free process according to claim 1 wherein
said mole ratio is 12:1 to 7:1.
4. A continuous, solvent-free process according to claim 1 wherein
the drying step is carried out at 40.degree. to 100.degree. C.
under vacuum or atmospheric pressure.
5. A continuous, solvent-free process according to claim 1 wherein
the average residence time of reactants in the reactor during the
process is about 0.5 to 5 hours.
Description
CROSS REFERENCE TO RELATED PATENT APPLICATION
[0001] This application is a continuation-in-part of pending U.S.
patent application Ser. No. 09/596,297, filed Jun. 15, 2000.
DESCRIPTION OF RELATED U.S. PATENTS
[0002] This invention is related to U.S. Pat. Nos. 5,959,053 and
5,939,506 assigned to the same assignee as herein.
BACKGROUND OF THE INVENTION
[0003] 1. Field of the Invention
[0004] This invention relates to copolymers of maleic anhydride and
a C.sub.1-C.sub.4 alkyl vinyl ether, and, more particularly, to a
continuous, solvent-free process for making solvent-free, fine
white powders of such copolymers having advantageous properties
useful for oral care compositions.
[0005] 2. Description of the Prior Art
[0006] A batch, solvent-free process (i.e. no solvent other than
reactants themselves) for making fine powders of high molecular
alternating copolymers of maleic anhydride (MAN) and a
C.sub.1-C.sub.4 alkyl vinyl ether (AVE) having a molecular
structure of (A-B).sub.n where A=MAN, B=AVE and n is an integer
which is indicative of its molecular weight, is described in U.S.
Pat. Nos. 5,959,053 and 5,939,506. In such process, excess AVE
monomer is present over a 1:1 molar ratio of monomers, to function
both as reactant and solvent in the system. No other solvent is
present in the reactor. Accordingly, after stripping the excess AVE
from the reaction product, a solvent-free copolymer is obtained.
However, a batch process requires an extended amount of time to
effect the reaction, usually necessitating about 9-13 hours to
complete each batch.
[0007] Accordingly, it is an object of this invention to provide a
continuous, solvent-free process for making solvent-free, fine
white powders of copolymers of MAN and AVE having advantageous
properties useful for oral care compositions.
SUMMARY OF THE INVENTION
[0008] What is described herein is a continuous, solvent-free
process for obtaining solvent-free, fine white powders of high
molecular weight alternating copolymers of maleic anhydride and a
C.sub.1-C.sub.4 alkyl vinyl ether, without odor or taste, having
the molecular structure (A-B).sub.n, where A is maleic anhydride, B
is an alkyl vinyl ether, and n is an integer indicative of the
molecular weight of the copolymer. The process herein comprises
feeding continuously alkyl vinyl ether as monomer reactant and
solvent in excess of the desired 1:1 mole ratio of A:B in the
copolymer, molten maleic anhydride and a free radical initiator, at
predetermined feeding rates, into a reactor heated at a reaction
temperature of about 50.degree. to 100.degree. C., charging the
reactor and withdrawing reaction product, residual alkyl vinyl
ether and initiator from the reactor at the same rate as the feed
rate of reactants into the reactor simultaneously thereby
maintaining a constant volume in the reactor, stripping residual
alkyl vinyl ether from the reaction product, drying the copolymer
obtained of any remaining traces of alkyl vinyl ether, and
recycling recovered alkyl vinyl ether back into reactor.
[0009] In the preferred embodiments of the continuous solvent-free
process of the invention, the alkyl vinyl ether is methyl vinyl
ether, the mole ratio of methyl vinyl ether to molten maleic
anhydride is about 25:1 to 5:1, most preferably 12:1 to 7:1. The
initiator concentration is 0.01 to 0.2% based on the weight of
copolymer, and the % copolymer solids removed from the
polymerization reactor is about 10 to 40%.
DETAILED DESCRIPTION OF THE INVENTION
[0010] Referring now to the FIGURE, which is a schematic drawing
for making solvent-free copolymers of maleic anhydride (MAN) and
C.sub.1-4 alkyl vinyl ethers (AVE) by a continuous, solvent-free
process. The continuous solvent-free process of the invention
consists of the solvent feed system 100, the molten maleic
anhydride feed system 200, the catalyst or initiator feed system
300, the reactor system 400, the product recovery and drier systems
500 and 600, and the solvent recovery system 700 and 800.
[0011] The average residence time* of the monomers in the reactor
system should be sufficient to completely react MAN, e.g. from 0.5
to 5 hours. To ensure complete reaction of MAN, higher temperature
and/or initiator booster can be used at the end of reaction zone.
The specific viscosity (SV) of the copolymer is controlled by
adding a chain transfer agent, preferably acetaldehyde, to the AVE
and/or by controlling the reaction temperature and/or the amount of
initiator. * The "average residence time" of monomer molecules
spent between inlet and outlet in the process is mathematically
equal to 1/feeding rate of reactants in vol./time X Vol of
Reactor.
[0012] In system 100, the liquified solvent monomer (methyl vinyl
ether) is pressurized and fed at a constant flow to the reactor
system 400 which may consist of a Continuous Stirred Tank Reactor
(CSTR) or of two or more CSTRs in series, or an agitated back mixed
reactor, or a plug flow tubular reactor, which is maintained at a
constant temperature between about 40.degree. C. to 120.degree. C.,
preferably 60-90.degree. C. Molten maleic anhydride (MAN), in 200,
also pressurized, is fed and mixed well with the solvent monomer at
a constant rate in the reactor; where, with a constant addition of
an initiator having a half-life of 2 to 10 hours, e.g. lauroyl or
decanoyl peroxide (or any other radical initiator) from 300, can
rapidly react to form a slurry of the desired solid product (10-40%
by weight) in the excess of liquid solvent monomer. In this
continuous process, the molar ratio of AVE/MAN in the reactor is
about 25:1 to 5:1, preferably about 12:1 to 7:1.
[0013] With the maintenance of a constant volume in the reactor,
the slurry mixture is continually withdrawn and fed to a low
pressure drier system 500; where, with the addition of heat, the
excess solvent monomer is vaporized and the solid product is
separated and removed. The recovered monomer is then cooled and
re-pressurized in the recovery system 800. Following compositional
adjustments, the monomer solvent is returned to the solvent feed
system 100.
[0014] AVE may be separated from polymer by continuous drying or by
filtration, and recycled after continuous purification e.g. by
continuous distillation, washing with water of pH>9, and
drying.
[0015] While the invention has been described with particular
reference to certain embodiments thereof, it will be understood
that changes and modifications may be made which are within the
skill of the art. Accordingly, it is intended to be bound only by
the following claims, in which:
* * * * *