Process for continuous synthesis of polymer compositions as...

Details Process for continuous synthesis of polymer compositions as... Process for continuous synthesis of polymer compositions as...

2000-11-13

2003-10-28

Zalukaeva, T. (Department: 1713)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Polymers from only ethylenic monomers or processes of...

C526S145000, C526S146000, C526S147000, C526S307100, C526S319000, C526S318400, C526S090000, C526S096000, C526S135000, C526S118000

Reexamination Certificate

active

06639029

ABSTRACT:

The invention relates to processes for synthesis of polymer compositions, wherein ethylenically unsaturated monomers are polymerized by means of initiators containing a transferable atom or group of atoms and one or more catalysts comprising at least one transition metal in the presence of ligands which can form a coordination compound with the metal catalyst or catalysts.
Radical polymerization is an important commercial process for synthesis of diverse polymers, such as PMMA and polystyrene. It suffers from the disadvantage that it is relatively difficult to control the composition of the polymers, the molecular weight and the molecular weight distribution.
One solution to this problem is offered by the so-called ATRP process (=Atom Trasfer Radical Polymerization). It is assumed that this process comprises “living” radical polymerization, although the description of the mechanism is not to be construed as limitative. In this process a transition metal compound is reacted with a compound containing a transferable atom or group of atoms. Under these conditions the transferable atom or group of atoms is transferred to the transition metal compound, whereby the metal is oxidized. A radical that adds onto the ethylenic groups is formed in this reaction. The transfer of the atom or group of atoms to the transition metal compound is reversible, however, and so the atom or group of atoms is transferred back to the growing polymer chain, whereby a controlled polymerization system is formed. Accordingly, it is possible to control the composition of the polymer, the molecular weight and the molecular weight distribution.
This reaction procedure is described, for example, by J-S. Wang et al., J. Am. Chem. Soc., Vol. 117, pp. 5614-5615, and by Matyjaszewski, Macromolecules., Vol. 28, pp. 7901-7910 (1995). Furthermore, International Patent Applications WO 96/30421, WO 97/47661, WO 97/18247, WO 98/20050, WO 98/40415 and WO 99/10387 disclose modifications of the aforesaid ATRP.
The mechanism described hereinabove is not undisputed. WO 97/47661, for example, states that polymerization takes place by insertion, and not by a radical mechanism. Such a differentiation is not pertinent to the present invention, however, since in the reaction procedure disclosed in WO 97/47661 there are used compounds which are also employed for ATRP.
The monomers, transition metal catalysts, ligands and initiators are chosen on the basis of the polymer solution desired. It is assumed that a high rate constant of the reaction between the transition metal/ligand complex and the transferable atom or group of atoms as well as a low equilibrium concentration of free radicals, is essential for a narrow molecular weight distribution. If the free radical concentration is too high, typical termination reactions will occur, leading to a broad molecular weight distribution. The exchange rate depends, for example, on the transferable atom or group of atoms, on the transition metal, on the ligands and on the anion of the transition metal compound. The person skilled in the art will find valuable advice on selection of these compounds in, for example, International Patent WO 98/40415.
The advantages of known ATRP processes, however, are largely limited to monomers which are themselves polar or which are readily soluble in polar media. Certainly the occasional use of nonpolar aprotic hydrocarbons such as benzene, toluene, xylene, cyclohexane and hexane is also known from the literature, but the polymers synthesized with these solvents exhibit much greater polydispersity. This effect is described in, for example, WO 98/40415.
The same document also discloses the possibility of polymerizing polar monomers such as methyl methacrylate or styrene by means of metallic copper, but the molecular weight distribution is much more unfavorable than in the use of a mixture of Cu
0
/CuBr or Cu
0
/CuBr
2
.
In Pol. Preprint (ACS, Div. Pol. Chem)., 1999, 40(2), 432, M. J. Ziegler et al. state among other facts that the polymerization of t-butyl methacrylate is difficult to control if the said process takes place in bulk. Both the molecular weight and the polydispersity can be improved by using approximately 20 to 25 wt % of polar solvents. Of course, because of the limited solubility in polar solvents of ethylenically unsaturated ester compounds containing alkyl or heteroalkyl groups with at least 8 carbon atoms, it is difficult by means of the known ATRP processes to polymerize ethylenically unsaturated monomer mixtures that contain at least 50 wt % of ethylenically unsaturated ester compounds containing alkyl or heteroalkyl chains with at least 8 carbon atoms. Furthermore, depending on use, these large volumes of polar solvents must be separated from the composition after synthesis of the polymers.
A further disadvantage of the known ATRP processes can be seen in the fact that they have only limited suitability for applications on the large industrial scale. In the first place the batch sizes for polymerization cannot be arbitrarily increased, especially because of reasons of thermal control and mixing of the reaction composition. Furthermore, after each polymerization batch the reaction must be removed from the reaction vessel, the reaction vessel must be cleaned if necessary and the new educt composition must be introduced into the reaction vessel. The maximum polymer yield achievable per unit time by such ATRP processes is therefore reltively small.
From the industrial viewpoint, however, polymerization processes are required that can be scaled simply and in principle arbitrarily and that deliver the highest possible polymer yields per unit time. At the same time, it should be possible to carry out the polymerization processes simply and inexpensively. Intermediate steps such as emptying and possibly cleaning the reaction vessel must be avoided.
In view of the prior art, it was now an object of the present invention to provide, for synthesis of a polymer composition, a process that can be scaled simply and in principle arbitrarily and that delivers the highest possible polymer yields per unit time. In particular, it should be possible to carry out the process for synthesis of a polymer composition simply and inexpensively, without necessitating any intermediate steps such as emptying and cleaning the reaction vessel.
A further object of the present invention was also to provide, for synthesis of a polymer composition, a process in which the polymers contained in the composition have a structure in which at least 50 wt % comprises (meth)acrylates containing alkyl or heteroalkyl chains with at least 8 carbon atoms.
Another object of the present invention was that the polymers contained in the composition must have a narrow molecular weight distribution. In particular, it is intended that the use of relatively complex processes such as anionic polymerization for synthesis of the polymer mixture will be avoided.
A further object was also to be seen in providing, for synthesis of a polymer composition, a process which permits by simple procedures the synthesis of copolymers with a non-statistical structure, especially the synthesis of two-block, three-block and gradient copolymers.
Another object of the present invention was to provide a polymerization process by which polymers with higher or high molecular weights can be obtained.
Yet another object was to provide a process that can be performed inexpensively and applied on a large industrial scale. Furthermore, the process should be possible easily and simply with commercially available components.
These objects are achieved by a process for synthesis of a polymer composition having all features of claim 1, as are other objects which are not explicitly cited but which can be obviously derived or inferred from the relationships discussed herein in the introduction. Advantageous modifications of the inventive process are protected in the dependent claims which refer back to claim 1.
By using a process of the type mentioned in the introduction to polymerize ethylenically unsaturated mono

Affiliated with

Also associated with

Rating

Process for continuous synthesis of polymer compositions as... does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Process for continuous synthesis of polymer compositions as..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for continuous synthesis of polymer compositions as... will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3163112