Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
1999-11-30
2002-02-19
Wu, David W. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C526S092000, C526S095000, C526S124800, C526S335000, C526S344000, C525S192000, C525S217000, C525S221000, C525S222000
Reexamination Certificate
active
06348554
ABSTRACT:
The invention concern a method for preparation of a liquid polymer composition, where ethylenically unsaturated monomers are polymerized by means of initiators that have a transferable atomic group, and one or more catalysts that contain at least one transition metal, in the presence of ligands that can form a coordination compound with the metallic catalyst(s). The invention also concerns the use of these polymer compositions and a method for isolation of polymers from such a polymer solution.
Radical polymerization is an important commercial method for producing a large number of polymers such as PMMA and polystyrene. It is disadvantageous here that it is relatively difficult to control the constitution of the polymers, the molecular weight and the molecular weight distribution.
One solution to this problem is offered by the so called ATRP method (Atom Transfer Radical Polymerization). It is assumed that here one is dealing with a “living” radical polymerization without any limitation being intended by the description of the mechanism. In these methods a transition metal compound is reacted with a compound that has a transferable atomic group. Here the transferable atomic group is transferred to the transition metal compounds, whereby the metal becomes oxidized. A radical that adds to ethylenic groups is formed in this reaction. However, the transfer of the atomic group to the transition metal compound is reversible, so that the atomic group is transferred back to the growing polymer chain, through which a controlled polymerization system is formed. Accordingly, the constitution of the polymer, the molecular weight and molecular weight distribution can be controlled.
This reaction method is described, for example, by J-S. Wang, et al., J. Am. Chem. Soc., Vol. 117, pp. 5614-5615 (1995), by Matyjaszewski, Macromolecules, Vol. 28, pp. 7901-7910 (1995). Moreover, the patent applications WO 96/30421, WO 97/47661, WO 97/18247, WO 98/40415 and WO 99/10387 disclose variations of the ATRP, explained above.
The mechanism described above is not undisputed. For example, it is described in WO 97/47661 that the polymerization takes place not by a radical mechanism but rather by insertion. However, for the present invention this differentiation is immaterial, since with the reaction methods disclosed in WO 97/47661 compounds are used that are also used in an ATRP.
A disadvantage with the known ATRP polymerization method is the fact that the transition metal catalysts that are used have to be separated from the polymers, since the transition metals discolor the polymers and molded articles that may be made from them. On top of that, the metals can have undesirable effects, in each case according to the use of the polymers. Up to now the polymers had been precipitated from the solution by the addition of suitable compounds such as methanol, and then separated from the metal-containing solution by filtration or centrifuging. Moreover, the transition metal can be separated by chromatographic methods. These methods, however, are hardly suitable for large scale use, since they are time consuming and expensive.
Taking into account the prior art, it is now the task of this invention to make available a method for preparation of liquid polymer compositions that are essentially free of transition metal compounds, where the polymers contained in the composition are supposed to have a narrow molecular weight distribution. In particular, the use of expensive methods like chromatographic methods are supposed to be avoided in the separation of the transition metal compounds.
Another task was to specify a method that can be carried out at reasonable cost and can be used on an industrial scale. Moreover, the method should be able to be carried out with commercially available components in an easy and simple manner.
These tasks, as well as other tasks that are not explicitly mentioned but which can easily be derived or developed from the introductory material, are solved by a method for preparation of a liquid polymer composition with all of the characteristics of claim
1
. Protection is provided for suitable modifications of the method in accordance with the invention in the subclaims that relate back to claim
1
. With regard to the method for preparation of polymers, claim
13
provides a solution of the underlying task, while claim
14
protects a preferred use of a polymer solution prepared in accordance with the present method.
Because the transition metal of the catalyst is oxidized after the polymerization and the catalyst is then separated by filtration, where the composition contains a solvent with a dielectric constant ≦4, it is possible to make available a not readily foreseeable method for preparation of a liquid polymer composition that is essentially free of transition metal compounds, where ethylenically unsaturated monomers are polymerized by means of initiators that exhibit transferable atomic groups, and one or more catalysts that include at least one transition metal, in the presence of ligands that can form a coordination compound with the metallic catalyst. This manner of preparation can be carried out at especially reasonable costs.
The fact that the catalysts can be separated by a traditional filtration method if the composition has a solvent with a dielectric constant ≦4 is particularly surprising since many of the compositions used for ATRP are heterogeneous systems. If these reaction mixtures are filtered, one finds that a considerable part of the transition metal catalyst does not remain behind on the filter, since the particle size of the catalyst is too small. An essentially complete separation from the composition is not possible. Here one should in particular bear in mind that the resulting polymers elevate the viscosity of the composition, so that the pore size of the filter cannot be chosen to be as small as one wishes.
At the same time a number of additional advantages can be achieved through the method in accordance with the invention. Among these are:
A narrow distribution of the polymers in the polymer composition prepared by the method.
The method in accordance with the invention enables excellent control of the molecular weight of the polymers contained in the compositions.
The conduct of the polymerization is relatively unproblematic with respect to pressure, temperature and solvent, and results that are acceptable under certain circumstances are achieved even at moderate temperatures.
The method in accordance with the invention is low in side reactions.
The method can be carried out at reasonable costs.
Polymers with a predefined constitution and targeted structure can be produced by means of the method of this invention.
Any radically polymerizable monomer can serve as a monomer in this invention. However, particularly suitable as monomers for polymerization in accordance with this invention are monomers that correspond to the formula:
where R
1*
and R
2*
are independently selected from the group consisting of hydrogen, halogens, CN, linear or branched alkyl groups with 1 to 20, preferably 1 to 6 and especially preferably 1 to 4 carbon atoms, which can be substituted with 1 to (2n+1) halogen atoms, where n is the number of carbon atoms of the alkyl group (for example CF
3
), &agr;, &bgr;-unsaturated linear or branched alkenyl or alkynyl groups with 2 to 10, preferably 2 to 6 and especially preferably 2 to 4 carbon atoms, which can be substituted with 1 to (2n−1) halogen atoms, preferably chlorine, where n is the number of carbon atoms of the alkyl group, for example CH
2
═CCl—, cycloalkyl groups with 3 to 8 carbon atoms, which can be substituted with 1 to (2n−1) halogen atoms, preferably chlorine, where n is the number of carbon atoms of the cycloalkyl group; C(═Y*)R
5*
, C(═Y*)NR
6*
R
7*
, Y*C(═Y*)R
5*
, SOR
5*
, SO
2
R
5*
, OSO
2
R
5*
, NR
8*
SO
2
R
5*
, PR
5*
2
, P(═Y*)R
5*
2
, Y*PR
5*
2
, Y*P(
50
Y*)R
5*
2
, NR
8*
2
, which can be quatemized with an additional R
8*
, aryl, or heterocyclyl group, where Y* can
Eisenberg Boris
Mueller Michael
Roos Sebastian
RohMax Additives GmbH
Wu David W.
Zalukawa Tanya
LandOfFree
Method for preparation of a liquid polymer composition and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for preparation of a liquid polymer composition and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for preparation of a liquid polymer composition and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2967047