Process for preparation of a dendritic polyol

Details Process for preparation of a dendritic polyol Process for preparation of a dendritic polyol

2000-02-29

2001-04-03

Troung, Duc (Department: 1711)

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

Synthetic resins

From ketone or ketene reactant

C528S230000, C528S247000, C528S272000, C525S437000, C525S441000

Reexamination Certificate

active

06211329

ABSTRACT:

The present invention relates to a process for synthesis of a polymeric polyalcohol (polyol) substantially and preferably built up from polyester units, optionally in combination with ether, polyether, amide or polyamide units. The polymeric polyalcohol is a hyperbranched dendritic polyester alcohol having reactive or protected terminal hydroxyl groups, which polyester alcohol is synthesized by repeated addition of acetal protected chain extenders to an initiator molecule, whereby each addition is followed by deprotection in the form of acetal decomposition and product recovery. The initiator molecule has n reactive unprotected groups to which n branches each consisting of g branching generations are added, whereby n and g are integers and at least 1. The branching generations comprises at least one polymeric or monomeric branching chain extender having three reactive groups of which two are acetal protected hydroxyl groups.
Compounds with a highly branched, treelike, molecular structure have been known for a long time. Literature discussing various hyperbranched and dendritic molecules and macromolecule include:
“Polybenzyl Type Polymers” by Howard C. Haas et al published in
J. Polymer Sci.
col XV (1995) pp. 503-515, wherein nonrandomly substituted highly branched benzyl type polymers are synthesized and analysed.
“Strukturuntersuchungen an Sternmolekülen mit Glykogen als Kern” by Walther Burchard et al published in
Makromolekulare Chemie
150 (1971) pp. 63-71, wherein the structure of molecules having treelike amylose chains and a glycogen core are disclosed.
“Statistical Mechanism of Random Coil Networks” and “Elasticity and Chain Dimensions in Gaussian Networks”, by William W. Graessley published in pp 865-868, wherein molecules comprising tri and tetrafunctional central cores (initiators) and concentrically treelike (dendritic) branches are disclosed. The term micronetworks is introduced to describe these molecules.
“Static and Dynamic Scattering Behaviour of Regularly Branched Chains: A Model of Soft-Sphere Microgels” by Walther Burchard et al published in
J. Polymer Sci. Polym. Phys. Ed.
vol 20 (1982) pp. 157-171, wherein is disclosed, among other models, the theory behind a molecular model comprising a trifunctional core being symmetrically branched whereby continued branch replication yields increased branch multiplicity and an increased number of terminal groups.
The birth of dendritic or “cascade” chemistry is formally realized in the first reported preparation, separation and characterization of structures with branched topologies obtained via an iterative methodology “‘Cascade’—and ‘Nonskid-Chain-Like’ Synthesis of Molecular Cavity Topologies”—
Synthesis
1978, pp. 155-158, E. Buhleier et al.
Structures such as starbranched, dense starbranched, dendrimers and hyperbranched dendritic molecules and macromolecules are from these and a large number of similar works published in the 1950's, 1960's and especially in the 1970's easily visualized but not easily synthesized.
Various hyperbranched and dendritic materials have during the last one or two decades attracted general attention. Patents, patent applications and other works issued or published during the last decades are summarized by for instance H. Galina et al in
Polymery;
English translation in
Int. Polym. Sci. Tech.
1995, 22, 70.
Hyperbranched dendritic macromolecules, including dendrimers, can generally be described as three dimensional highly branched molecules having a treelike structure. Dendrimers are highly symmetric, while similar macromolecules designated as hyperbranched and/or dendritic may to a certain degree hold an asymmetry, yet maintaining the highly branched treelike structure. Dendrimers can be said to be monodisperse-determined molecular weight (M
w
)
ominal molecular weight (M
n
)=1—or substantially monodisperse (M
w
/M
n
≈1) hyperbranched macromolecules. Hyperbranched and dendritic macromolecules normally consist of an initiator or nucleus having one or more reactive sites and a number of branching layers and optionally a layer of chain terminating molecules. Continued replication of branching layers normally yields increased branch multiplicity and, where applicable or desired, increased number of terminal groups. The layers are usually called generations and the branches dendrons, which are designations hereinafter used.
Synthesis of perfect dendritic material, that is substantially monodisperse molecules comprising symmetrical treelike (dendritic) branches which optionally emanate symmetrically as well as concentrically from a core or initiator molecule, is a challenging task as high yield and selectivity is required in all reaction steps. Various processes have been suggested for dendritic, near dendritic and perfect dendritic products, but complex and inefficient synthesis is still an obstacle to technical and commercial use of monodisperse dendritic products. Most disclosed processes yield either polydisperse and/or too expensive products. A number of patents and patent applications disclosing various hyperbranched and/or dendritic macromolecules and processes for synthesis thereof have for various types of products been issued or published and include EP 0 115 771, SE 468 771, WO 93/18075, EP 0 575 596, SE 503 342 and U.S. Pat. No. 5,561,214.
EP 0 115 771 claims a dense star polymer having at least three symmetrical core branches, each core branch having at least one terminal group, and a ratio terminal groups to core branches being greater than 2:1. The properties of claimed polymer is specified through a comparative relation to an unspecified and allegedly known star polymer. Claim
1
can due to inoperable teaching of terminal groups and unspecified comparison not be interpreted. EP 0 115 771 also relates to a process, which process substantially also is disclosed in U.S. Pat. No. 4,410,688, for synthesis of a symmetrical dense star polymer. The process teaches a repeated and alternately addition of alkyl acrylate and alkylene diamine to a core consisting of ammonia.
SE 468 771 discloses a hyperbranched dendritic macromolecule substantially built up from polyester units and a process for synthesis of said macromolecule. The macromolecule is composed of an initiator, having at least one hydroxyl group, to which initiator at least one branching generation comprising at least one chain extender, having at least one carboxyl group and at least two hydroxyl groups, is added. The macromolecule is optionally chain terminated. The process for synthesis of said macromolecule teaches a co-esterification of the initiator and the chain extender, optionally followed by a chain termination. The process yield inexpensive polydisperse hyperbranched dendritic macromolecules.
WO 93/18075 teaches a hyperbranched polymer having at least six terminal hydroxyl or carboxyl groups and a process for its synthesis. The hyperbranched polymer is synthesized by repeated and alternately addition of a compound having at least one anhydride group followed by a compound having at least one epoxide group to a nucleus having at least one hydroxyl group.
EP 0 575 596 discloses a dendritic macromolecule comprising a core having 1-10 functional groups and branches synthesized from vinyl cyanide units as well as a process for synthesis thereof. The process involves three repeated steps beginning with a reaction between the core and monomeric vinyl cyanide units followed by reduction of incorporated nitrile groups to amine groups. In a third step said amine groups are reacted with monomeric vinyl cyanide units.
SE 502 342 discloses a hyperbranched dendritic macromolecule of polyester type and a process for synthesis of said macromolecule. The macromolecule is substantially composed of a nucleus, having at least one epoxide group, to which nucleus at least one branching generation comprising at least one chain extender, having at least three reactive functions of which at least one is a carboxyl or epoxide group and at least one is a hydroxyl group, is added. The macromolecule is optio

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