Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
2001-12-11
2004-01-27
Chang, Ceila (Department: 1625)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C546S016000, C546S019000, C546S020000, C546S064000, C546S186000, C546S218000, C546S223000, C546S225000, C544S180000
Reexamination Certificate
active
06683142
ABSTRACT:
The present invention relates to 1-alkoxy-polyalkyl-piperidine derivatives, a polymerizable composition comprising a) at least one ethylenically unsaturated monomer and b) a 1-alkoxy-polyalkyl-piperidine derivative. Further aspects of the present invention are a process for polymerizing ethylenically unsaturated monomers, and the use of 1-alkoxy-polyalkyl-piperidine derivatives for controlled polymerization. The intermediate N-oxyl derivatives, a composition of the N-oxyl derivatives with ethylenically unsaturated monomers and a free radical initiator X., as well as a process for polymerization are also subjects of the present invention.
The compounds of the present invention provide polymeric resin products having low polydispersity. The polymerization process proceeds with enhanced monomer to polymer conversion efficiency. In particular, this invention relates to stable free radical-mediated polymerization processes which provide homopolymers, random copolymers, block copolymers, multiblock copolymers, graft copolymers and the like, at enhanced rates of polymerization and enhanced monomer to polymer conversions.
Polymers or copolymers prepared by free radical polymerization processes inherently have broad molecular weight distributions or polydispersities which are generally higher than about four. One reason for this is that most of the free radical initiators have half lives that are relatively long, ranging from several minutes to many hours, and thus the polymeric chains are not all initiated at the same time and the initiators provide growing chains of various lengths at any time during the polymerization process. Another reason is that the propagating chains in a free radical process can react with each other in processes known as combination and disproportionation, both of which are irreversibly chain-terminating reaction processes. In doing so, chains of varying lengths are terminated at different times during the reaction process, resulting in resins consisting of polymeric chains which vary widely in length from very small to very large and which thus have broad polydispersities. If a free radical polymerization process is to be used for producing narrow molecular weight distributions, then all polymer chains must be initiated at about the same time and termination of the growing polymer-chains by combination or disproportionation processes must be avoided.
Conventional radical polymerization reaction processes pose various significant problems, such as difficulties in predicting or controlling the molecular weight, the polydispersity and the modality of the polymers produced. These prior art polymerization processes produce polymers having broad polydispersities and in some instances, low polymerization rates. Furthermore, free radical polymerization processes in bulk of the prior art are difficult to control because the polymerization reaction is strongly exothermic and an efficient heat removal in the highly viscous polymer is mostly impossible. The exothermic nature of the prior art free radical polymerization processes often severely restricts the concentration of reactants or the reactor size upon scale-up.
Due to the above mentioned uncontrollable polymerization reactions, gel formation in conventional free radical polymerization processes are also possible and cause broad molecular weight distributions and/or difficulties during filtering, drying and manipulating the product resin.
U.S. Pat. No. 4,581,429 to Solomon et al., issued Apr. 8, 1986, discloses a free radical polymerization process which controls the growth of polymer chains to produce short chain or oligomeric homopolymers and copolymers, including block and graft copolymers. The process employs an initiator having the formula (in part) R′R″N—O—X, where X is a free radical species capable of polymerizing unsaturated monomers. The reactions typically have low conversion rates. Specifically mentioned radical R′R″N—O. groups are derived from 1,1,3,3 tetraethylisoindoline, 1,1,3,3 tetrapropylisoindoline, 2,2,6,6 tetramethylpiperidine, 2,2,5,5 tetramethylpyrrolidine or di-t-butylamine. However, the suggested compounds do not fulfill all requirements. Particularly the polymerization of acrylates does not proceed fast enough and/or the monomer to polymer conversion is not as high as desired.
Recently other attempts to develop new polymerization regulators have been published. WO 98/4408 and WO 98/30601 disclose heterocyclic compounds suitable for controlled polymerization processes. WO 98/13392 discloses open chain alkoxyamines which are derived from NO gas or from nitroso compounds.
EP-A-735 052 discloses a method for preparing thermoplastic polymers of narrow poly-dispersities by free radical-initated polymerization, which comprises adding a free radical initiator and a stable free radical agent to the monomer compound.
This method has the disadvantage that uncontrollable recombinations of initiator radicals may occur immediately after their formation, thus producing variable ratios between initiator radicals and stable free radicals. Consequently in some cases there is no good control of the polymerization process.
There is therefore still a need for polymerization processes for the preparation of narrow polydispersity polymeric resins with defined molecular weights using the economical free radical polymerization techniques. These polymerization processes will also control the physical properties of the polymers such as viscosity, hardness, gel content, processability, clarity, high gloss, durability, and the like.
The polymerization processes and resin products of the present invention are useful in many applications, including a variety of specialty applications, such as for the preparation of block copolymers which are useful as compatibilizing agents for polymer blends, or dispersing agents for coating systems or for the preparation of narrow molecular weight resins or oligomers for use in coating technologies and thermoplastic films or as toner resins and liquid immersion development ink resins or ink additives used for electrophotographic imaging processes.
Surprisingly, it has now been found that it is possible to overcome the afore mentioned shortcomings of the prior art by providing a polymerizable composition containing specific initiator compounds. Polymerization of the composition results in a polymer or copolymer of narrow polydispersity and a high monomer to polymer conversion even at relatively low temperatures and at short reaction times, making the polymerization process particularly suitable for industrial applications. The resulting copolymers are of high purity and in many cases colorless, therefore not requiring any further purification.
One object of the present invention is to provide a 1-alkoxy-polyalkyl-piperidine derivative containing a structural element of formula (I):
wherein
G
1
, G
2
, G
3
, G
4
are independently C
1
-C
6
alkyl with the proviso that at least one is not methyl or G
1
and G
2
or G
3
and G
4
, or G
1
and G
2
and G
3
and G
4
together form a C
5
-C
12
cycloalkyl group;
G
5
, G
6
independently are H, C
1
-C
18
alkyl, phenyl, naphthyl or a group COOC
1
-C
18
alkyl and X represents a group having at least one carbon atom and is such that the free radical X. derived from X is capable of initiating polymerization of ethylenically unsaturated monomers, with the proviso that compounds A1 and A2 are excluded:
The alkyl radicals in the various substituents may be linear or branched. Examples of alkyl containing 1 to 18 carbon atoms are methyl, ethyl, propyl, isopropyl, butyl, 2-butyl, isobutyl, t-butyl, pentyl, 2-pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, t-octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, hexadecyl and octadecyl.
C
5
-C
12
cycloalkyl is typically, cyclopentyl, methylcyclopentyl, dimethylcyclopentyl, cyclohexyl, methylcyclohexyl.
Preferred compounds or mixture of compounds are any of formulae A to S;
wherein
G
1
, G
2
, G
3
and G
4
are independently alkyl of 1 to 4 carbon atoms, or G
1
and G
2
tog
Kramer Andreas
Nesvadba Peter
Chang Ceila
Ciba Specialty Chemicals Corporation
Stevenson Tyler A.
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