Heterocyclic alkoxyamines as regulators in controlled...

Details Heterocyclic alkoxyamines as regulators in controlled... Heterocyclic alkoxyamines as regulators in controlled...

2002-07-09

2003-12-16

Pezzuto, Helen L. (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

Reexamination Certificate

active

06664353

ABSTRACT:

The present invention relates to heterocyclic alkoxyamine compounds, a polymerizable composition comprising a) at least one ethylenically unsaturated monomer and b) a heterocyclic alkoxyamine compound. Further aspects of the present invention are a process for polymerizing ethylenically unsaturated monomers, and the use of heterocyclic alkoxyamine compounds for controlled polymerization. The intermediate N-oxyl derivatives, a composition of the N-oxyl derivatives with ethylenically unsaturated monomers and a free radical initiator, as well as a process for polymerization are also subjects of the present invention. Further subjects of the invention are novel amine precursors and a novel process for manufacturing 5-ring heterocyclic amines.
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. 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.
WO 98/13392 describes open chain alkoxyamine compounds which have a symmetrical substitution pattern and are derived from NO gas or from nitroso compounds.
EP-A-735 052 discloses a method for preparing thermoplastic polymers of narrow polydispersities by free radical-initated polymerization, which comprises adding a free radical initiator and a stable free radical agent to the monomer compound.
WO 96/24620 describes a polymerization process in which very specific stable free radical agents are used, such as for example
WO 98/30601 discloses specific nitroxyls based on imidazolidinons. Nitroxylethers are generically mentioned but not specifically disclosed.
WO 98/44008 discloses specific nitroxyls based on morpholinones, piperazinones and piperazindiones. The nitroxylethers are also generically mentioned but not specifically disclosed.
Despite the above mentioned attempts to improve the control of radical polymerization reactions there is still a need for new polymerization regulators, which are highly reactive, and give an equally good or better control of the molecular weight of the polymer.
Surprisingly it has been found that particularly 5 and 6 membered heterocyclic alkoxyamines or their nitroxyl precursors, which have a high sterical hindrance in &agr;-position to the alkoxyamine group lead to regulators/initiators which allow polymerization very efficient and fast at higher temperatures, but also work at relatively low temperatures such as for example 100° C. The higher sterical hindrance may be introduced by at least one higher alkyl substituent than methyl in &agr;-position to the alkoxyamine group. In many cases even higher hindrance by two, three or four higher alkyl groups may be advantageous. The higher sterical hindrance may be also advantageous for 7 and 8 membered heterocyclic alkoxyamines or their nitroxyl precursors.
One subject of the present invention is a polymerizable composition, comprising
a) at least one ethylenically unsaturated monomer or oligomer, and
b) a compound of formula (Ia) or (Ib)
wherein
R
1
, R
2
, R
3
and R
4
independently of each other are C
1
-C
18
alkyl, C
3
-C
18
alkenyl, C
3
-C
18
alkinyl, C
1
-C
18
alkyl, C
3
-C
18
alkenyl, C
3
-C
18
alkinyl which are substituted by OH, halogen or a group —O—C(O)—R
5
, C
2
-C
18
alkyl which is interrupted by at least one O atom and/or NR
5
group, C
3
-C
12
cycloalkyl or C
6
-C
10
aryl or R
1
and R
2
and/or R
3
and R
4
together with the linking carbon atom form a C
3
-C
12
cycloalkyl radical;
with the proviso that if Q in formula (Ia) is a direct bond, —CH
2
— or CO, at least one of R
1
, R
2
, R
3
or R
4
is different from methyl;
R
5
, R
6
and R
7
independently are hydrogen, C
1
-C
18
alkyl or C
6
-C
10
aryl;
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;
Z
1
is O or NR
8
;
R
8
is hydrogen, OH, C
1
-C
18
alkyl, C
3
-C
18
alkenyl, C
3
-C
18
alkinyl, C
1
-C
18
alkyl, C
3
-CC
18
alkenyl, C
3
-C
18
alkinyl which are substituted by one or more OH, halogen or a group —O—C(O)—R
5
, C
2
-C
18
alkyl which is interrupted by at least one O atom and/or NR
5
group, C
3
-C
12
cycloalkyl or C
6
-C
10
aryl, C
7
-C
9
phenylalkyl, C
5
-C
10
heteroaryl, —C(O)—C
1
-C
18
alkyl, —O—C
1
-C
18
alkyl or —COOC
1
-C
18
alkyl;
Q is a direct bond or a divalent radical CR
9
R
10
, CR
9
R
10
—CR
11
R
12
, CR
9
R
10
CR
11
R
12
CR
13
R
14
, C(O) or CR
9
R
10
C(O), wherein R
9
, R
10
, R
11
, R
12
, R
13
and R
14
are independently hydrogen, phenyl or C
1
-C
18
alkyl;
with the proviso that the compounds (A) and (B) are excluded
Halogen is F, Cl, Br or I, preferably Cl or Br.
The alkyl radicals in the various substituent

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