Continuous process for the production of controlled...

Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymerizing in tubular or loop reactor

Reexamination Certificate

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C526S173000, C526S263000, C526S265000, C526S328500, C526S329100, C526S328000, C526S338000, C526S347000

Reexamination Certificate

active

06716935

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a continuous process for the production of polymer using high solids loadings of polymerizable monomers in a stirred, plug-flow, temperature-controlled reactor.
BACKGROUND INFORMATION
Various types of polymers can be prepared from different monomeric materials, the particular type formed being generally dependent upon the procedures followed in contacting the materials during polymerization. For example, random copolymers can be prepared by the simultaneous reaction of the copolymerizable monomers. Block copolymers are formed by sequentially polymerizing different monomers. Useful classes of polymers can be synthesized via anionic, cationic, and free-radical methods.
SUMMARY OF THE INVENTION
An ongoing need exists for processes that allow for continuously making controlled architecture polymers. Controlled architecture refers to a polymer with a designed topology (linear, branched, star, combination network), composition (block copolymer, random copolymer, homopolymer, graft copolymer, tapered or gradient copolymer), and/or functionality (end, site specific, telechelic, multifunctional, macromonomers). Of particular importance is the ability to perform controlled architecture polymerizations at high monomer concentrations or in the absence of solvent. Polymerizations at high solids offer beneficial economic and environmental advantages. The present invention addresses that need.
As used herein:
“axial mixing” means mixing in a direction parallel to the overall direction of flow in a reactor;
“block copolymer” means a polymer having at least two compositionally discrete segments, e.g., a di-block copolymer, a tri-block copolymer, a random block copolymer, and a star-branched block copolymer;
“branching agent” means a multifunctional anionically polymerizable monomer or multifunctional quenching or coupling agent, the addition of which results in the formation of starbranched polymer;
“continuous” means that reactants enter a reactor at the same time (and, generally, at the same rate) that polymer product is exiting the same reactor;
“di-block copolymer” or “tri-block copolymer” means a polymer in which all the neighboring monomer units (except at the transition point) are of the same identity, e.g., -AB is a di-block copolymer comprised of an A block and a B block that are compositionally different, ABA is a tri-block copolymer in which the A blocks are compositionally the same, but different from the B block, and ABC is a tri-block copolymer comprised of A, B, and C blocks, each compositionally different;
“high solids loading” refers to a solution in which the initial reactants and/or reaction products comprise more than 50 wt % solids to an upper limit of 100 wt % solids;
“living anionic polymerization” means, in general, a chain polymerization that proceeds via an anionic mechanism without chain termination or chain transfer. (For a more complete discussion of this topic, see
Anionic Polymerization Principles and Applications
. H. L. Hsieh, R. P. Quirk, Marcel Dekker, NY, N.Y. 1996. Pg 72-127);
“living end” means a polymerizable reactive site , present in the absence of termination at the end of a polymer chain;
“oligomeric” means a polymer molecule consisting of only a few monomer units (e.g., dimers, trimers, tetramers);
“plug” means a three dimensional slice of the reaction mixture;
“plug flow reactor (PFR)” means a reactor that ideally operates without axial mixing (see An Introduction to Chemical Engineering Kinetics and Reactor Design; Charles G. Hill, J. Wiley and Sons 1977, p. 251) or shows no radial variation in concentration as materials are consumed as they travel in the axial direction (see Elements of Chemical Reaction Engineering; H. Scott Fogler, Prentice Hall, 1999;
“polydispersity” means the weight average molecular weight divided by the number average molecular weight; polydispersity is reported on a polydispersity index (PDI);
“radial mixing” means mixing in a direction perpendicular to the overall direction of flow in a reactor;
“random block copolymer” means a copolymer having at least two distinct blocks wherein at least one block comprises a random arrangement of at least two types of monomer units;
“reaction zone” means that portion of a reactor or reactor system where the majority of reaction occurs;
“residence time” means the time necessary for a theoretical plug of reaction mixture to pass completely through a reactor;
“segment” refers to a block of polymer formed by the addition of a specific monomer or a branching agent;
“starbranched polymer” means a polymer consisting of several linear chains linked together at one end of each chain by a single branch or junction point (See
Anionic Polymerization Principles and Applications
. H. L. Hsieh, R. P. Quirk, Marcel Dekker, NY, N.Y. 1996. Pg 333-368);
“star-branched block polymer” or “hyper-branched block copolymer” means a polymer consisting of several linear block chains linked together at one end of each chain by a single branch or junction point, also known as a radial block copolymer (See
Anionic Polymerization Principles and Applications
. H. L. Hsieh, R. P. Quirk, Marcel Dekker, New York, N.Y. 1996. Pg 333-368);
“temperature-sensitive monomer” means a monomer susceptible to significant side reactions of the living ends with reactive sites, such as carbonyl groups, on the same, or a different, polymer chain as the reaction temperature rises; and
“temperature profile” means the temperature or temperatures experienced by a reaction mixture plug over time as it moves through a reactor.
An advantage of at least one embodiment of the present invention is that the ability to control architectures at high solids offers increased convenience and favorable environmental considerations.
An advantage of at least one embodiment of the present invention is that the temperature of the reaction mixture can be controlled to such an extent that side reactions are minimized. This is especially advantageous when temperature-sensitive monomers are used.
Another advantage of at least one embodiment of the present invention is that the average molecular weight of resulting polymers can be controlled well by controlling the amount of initiator added to the reaction mixture.
Another advantage of at least one embodiment of the present invention is that various polymer architectures can be tailored and synthesized to be suitable for specific applications.
Another advantage of at least one embodiment of the present invention is that the ability to control the temperature enables the reaction materials to be maintained in solution, which facilitates the desired reaction.
Other advantages of at least one embodiment of the present invention is that it allows for controlled reaction kinetics, optimum reaction mixture viscosity and polymer solubility.


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patent: 0 936 225 (1999-08-01), None

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