Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Patent
1994-07-13
1995-05-23
Acquah, Samuel A.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
528271, 528274, 528279, 528281, 528282, 528283, 5282955, 528300, 528301, 528303, 528306, 525438, 525440, 525442, 525444, 5254445, 525445, 525449, 525450, C08F 2000
Patent
active
054183014
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/SE93/00148 filed Feb. 24, 1993.
The present invention relates to a dendritic macromolecule, comprising composed of a central initiator molecule or initiator polymer having one or more reactive groups (A), which groups (A) under formation of an initial tree structure are bonded to reactive carboxyl groups (B) of a monomeric chain extender containing the two reactive groups (A) and (B). The tree structure is optionally extended and further branched from the initiator molecule or initiator polymer by an addition of further molecules of a monomeric chain extender by means of bonding between the reactive groups (A) and (B) thereof and is optionally further extended by reaction with a chain stopper.
The invention also comprises a process for preparation of the dendritic macromolecule.
Various dendritic macromolecules, so called dendrimers are by Tamalia et al described in Angew. Chem. Int. Ed. Engl. 29 pages 138-175 (1990). The macromolecules hold a tree structure.
Products quite different from the present invention are in said publication described, which publication discloses the preparation of polyamide amines of the dendrimer type. As initiator molecule are NH.sub.3 used and as chain extender methyl acrylate and ethylene diamine. The yielded macromolecules are NH.sub.2 terminated. Chain stoppers are, according to this process, not used.
However, the present invention refers to a dendritic, that is a hyperbranched, macromolecule of the polyester type.
Ordinary polyesters are well-known and have been manufactured for a very long time. They exhibit many good properties but are also submitted to some drawbacks, which until now have been regarded as impossible to avoid.
An alkyd is a typical example of a polyester type having a very large commercial significance. Alkyds are normally used as components in paint binders.
The composition of an alkyd can be illustrated by the following structural formula ##STR1## where R.sub.1 is the alkyl moiety of an unsaturated fatty acid of such a type that it is reactive to air oxygen thereby providing the polyester with air drying properties
An alkyd is most often a high molecular and randomly branched compound with a broad dispersivity, which not is illustrated by above simplified formula. An alkyd exhibits due to this a very high viscosity and large amounts of solvents must thus be added to obtain so low a viscosity that it can be utilised.
Further examples are so called conventional polyesters. They are in principal composed similar to above structural formula, but with the difference that R.sub.1 is the alkyl moiety of a saturated monofunctional acid and that some of the alcohol moieties in the chain are unesterified, i.e. the polyesters contain unreacted hydroxyl groups. Curing is performed by a crosslinking between the unreacted hydroxyl groups and e.g. a melamine resin. The demand for viscosity reducing solvents is to obtain applicable lacquers in this case also very high.
According to the present invention above drawbacks have quite unexpectedly been avoided and a hyperbranched macromolecule of the dendrimer type has been brought about. The dendritic macromolecule according to the invention comprises a central initiator molecule or initiator polymer having one or more reactive groups (A), which groups (A) under formation of an initial tree structure are bonded to reactive groups (B) of a monomeric chain extender holding the two reactive groups (A) and (B), which tree structure optionally is extended and further branched from the initiator molecule or initiator polymer by an addition of further molecules of a monomeric chain extender through bonding between the reactive groups (A) and (B) thereof. The tree structure is optionally further extended by reaction with a chain stopper. The macromolecule is characterised in that the reactive groups (A) and (B) are hydroxyl groups (A) and carboxyl groups (B), respectively, and that the chain extender has at least one carboxyl group (B) and at least two hydroxyl groups (A) or hydroxyalkyl substitu
REFERENCES:
patent: 5041516 (1991-08-01), Frechet et al.
patent: 5136014 (1992-08-01), Figuly
Tomalia, et al. (1990) "Starburst Dendrimers: Molecular-Level Control of Size, Shape, Surface Chemistry, Topology, and Flexibility from Atoms to Macroscopic Matter", Angew. Chem. Int. Ed. Engl. 29:138-175.
Hult Anders
Johansson Mats
Malmstrom Eva
Sorensen Kent
Acquah Samuel A.
Perstorp AB
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