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
2002-06-11
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...
C526S328000, C526S328500, C526S090000, C526S095000
Reexamination Certificate
active
06403746
ABSTRACT:
The invention concerns a method for preparation of a composition that contains polymeric ester compounds with long-chain alkyl residues, where ethylenically unsaturated monomer mixtures, which contain at least 50 wt % ethylenically unsaturated ester compounds with alkyl or heteroalkyl chains with at least 6 carbon atoms, are polymerized with initiators that contain 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 preparation of a large number of polymers such as PMMA and polystyrene. It is disadvantageous here that the constitution of the polymers, the molecular weight and the molecular weight distribution are ralatively diffcult to control.
One solution to these problem is offered by the so called ATRP process (=Atom Transfer Radical Polymerization). It is assumed that this is a “living” radical polymerization without any limitation being intended by the description of the mechanism. In this method a transition metal compound is reacted with a compound that has a transferable atomic group. In doing so the transferable atomic group is transferred to the transition metal compound, so that the metal becomes oxidized. In this reaction a radical forms and adds to ethylenic groups. The transfer of the atomic group to the transition metal compound, however, is reversible, so that the atomic group is transferred back to the growing polymer chain, whereby 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), and 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, WO 97/47661 indicates that the polymerization takes place not via a radical mechanism but rather via insertion. However, for the present invention this differentiation is unimportant, since compounds are used in the reaction method disclosed in WO 97/47661 that are also used in an ATRP.
The monomers, the transition metal catalysts, the ligands and the initiators are chosen each according to the desired polymer solution. It is assumed that a high reaction rate constant for the reaction between the transition metal-ligand complex and the transferable atomic group and a low concentration of free radicals in equilibrium are important for a narrow molecular weight distribution. If the concentration of free radicals is too high, typical termination reactions that are responsible for a broad molecular weight distribution occur. The exchange rate is dependent, for example, on the transferable atomic group, the transition metal, the ligands and the anion of the transition metal compound. The specialist will find valuable advice for choosing these components in, for example, WO 98/40415.
The advantages of the known ATRP polymerization method are limited, however, to monomers that are themselves polar or that exhibit good solubility in polar media. The isolated used of nonpolar aprotic hydrocarbons like benzene, toluene, xylene, cyclohexane and hexane is also known from the litature, but the polymers made with these solvents have clearly higher polydispersities. This effect is described, for example, in WO 98/40415. In Pol. Preprint (ACS, Div. Pol. Chem.), 1999, 40(2), 432, M. J. Ziegler et al. described, among other things, the poor cotrollability of the polymerization of t-butyl methacrylate if it takes place in bulk. If about 20-25 wt % polar solvents are used, both the molecular weight as well as the polydispersity can be improved. However, ethylenically unsaturated monomer mixtures that contain at least 50 wt % ethylenically unsaturated ester compounds with alkyl or hetroalkyl chains that have at least 6 carbon atoms, because of the limited solubility of ethylenically unsaturated ester compounds with alkyl or heteroalkyl residues with at least 6 carbon atoms, can be polymerized only poorly in polar solvents using the known ATRP methods. Moreover, these large amounts of polar solvents, in each case according to use, have to be separated from the composition after preparation of the polymers.
Taking into account the prior art, it is now the task of this invention to make available a methods for preparation of a poly(methy)acrylate composition where the polmers contained in the composition are to be formed of at least 50 wt % (meth)acrylates with alkyl or heteroalkyl chains with at least 6 carbon atoms. Moreover, the polymers contained in the composition have a narrow molecular weight distribution. In particular, the use of costly methods, for instance anionic polymerization, is to be avoided in the preparation of the polymer of the mixture.
Another task was to provide a method that can be carried out on an economical basis that is usable in large scale industry. Moreover, it should be possible to conduct the method easily and simply with commercially available components.
These as well as other not explicitly mentioned tasks, which however can easily be derived or developed from the introductory material, are solved by a method for preparation of a poly(meth)acrylate composition with all of the characteristics of claim
1
. Expedient modifications of the method in accordance with the invention are protected in the subclaims that refer back to claim
1
. With regard to the method for preparation of polymers claim
13
offers a solution to the underlying task, while claim
14
protects a preferred use of a polymer solutions
By polymerizing ethylenically unsaturated monomers, which contain 50-100 wt %, with respect to the total weight of the ethylenically unsaturated monomers, of one or more ethylenically unsaturated ester compounds of formula (I)
where R is hydrogen or methyl, R
1
means a linear or branched alkyl residue with 6-40 carbon atoms, R
2
and R
3
independently mean hydrogen or a group of the formula —COOR′, where R′ is hydrogen or a linear or branched alkyl residue with 6-40 carbons atoms, in the presence of 5-95 wt % mineral oil with respect to the total weight of the composition, one succeeds in making available, in a not easily foreseeable way, a method for preparation of a poly(meth)acrylate composition, with which a narrow polymer distribution can be achieved. Here 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). This preparation method can be carried out on a particularly cost favorable basis and to that extent is of industrial unterest.
It is particularly surprising that mineral oils can be used as solvents with particular success because many of the compositions used for the ATRP polymerization method contain polar solvents. The polymerization of mixtures of etheylenically unsaturated monomers, which contain up to at least 50 wt % ethylenically unsaturated ester compounds with longer-chain alkyl or heteroalkyl chains with at least 6 carbon atoms is hindered by the limited solubility of these compounds in polar solvents. If nonpolar solvents are used instead, one finds that polymer mixtures with considerably greater polydispersities are obtained than when conventional polar solvents are used. Moreover, the polymer yields in nonpolar solvents are in many cases lower. The product properties of such widely distributed polymer properties [sic] are insufficient for many industrial
Bollinger Joseph Martin
Eisenberg Boris
Roos Sebastian
Scherer Markus
Cheung William K
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
RohMax Additives GmbH
Wu David W.
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