Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Rod – strand – filament or fiber
Patent
1999-03-17
2000-09-19
Acquah, Samuel A.
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Rod, strand, filament or fiber
528 80, 528 81, 528 83, 528272, 528288, 528289, 528300, 528301, 528302, 528306, 528307, 528308, 5283086, 525437, 525440, D02G 300, C08F 2000, C08G 6302
Patent
active
061208957
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
The present invention relates to biodegradable polyesters obtainable from building blocks dicarboxylic acid or its ester-forming derivative and ester-forming derivative and their mixtures (b.sub.11) or at least one compound (b.sub.12) which contains two functional groups capable of reacting with the end groups of polyester A or mixtures of b.sub.11 and b.sub.12, or at least one compound (b.sub.22) which contains three functional groups capable of reacting with the end groups of polyester A or mixtures of b.sub.21 and b.sub.22, or at least one compound (b.sub.32) which contains four functional groups capable of reaction with the end groups of polyester A or mixtures of b.sub.31 and b.sub.32 and isocyanurate (b.sub.41) or mixtures of different isocyanurates (b.sub.41).
The present invention furthermore relates to molding compositions which comprise the biodegradable polyesters, to processes for preparing the biodegradable polyesters and to their use for producing moldings, films or fibers. The invention furthermore relates to the moldings, films or fibers produced using the biodegradable polyesters.
Biodegradable polyesters which comprise repeating units derived from a mixture of aromatic and aliphatic dicarboxylic acids or their derivatives are disclosed, for example, in U.S. Pat. No. 5,446,079. This describes linear, random, semicrystalline polyesters having an intrinsic viscosity of about 0.5-1.8 dl/g (measured in phenol/tetrachloroethane, 60/40 ratio by weight, at a concentration of 0.5 g/100 ml and at 25.degree. C.), the dicarboxylic acid mixture comprising from 5 to 65 mol % of aliphatic and from 35 to 95 mol % of aromatic dicarboxylic acids.
Chain-extended or branched polyesters are likewise known. Also known are polyesters which are both branched and chain-extended. Diisocyanates are frequently used to extend the chains, and polyfunctional acids and/or alcohols are often employed as branching agents. Isocyanates of higher functionality, polyisocyanates, are generally used as crosslinkers. In order to produce moldings with thick walls, U.S. Pat. No. 3,553,157 recommends drum application of polyisocyanates before processing onto polyethylene terephthalate (PET) so that the PET crosslinks during processing. The molded articles produced in this way are, however, not free of specks; the surface quality is thus unsatisfactory. U.S. Pat. No. 2,999,851 describes, for example, linear polyesters which are chain-extended with diisocyanates and can be crosslinked with polyisocyanates. Polyesters modified in this way are, in particular, easily ground. However, they are not amenable to melt processing, nor are they suitable for preparing polymer blends. WO 89/11497 discloses polyesters from cycloaliphatic and aromatic monomers, which are branched in a first step and reacted with polyisocyanates in another step. These polyesters can be processed to films. A disadvantage is, however, that these polyesters are not thermoplastic. The films must therefore be produced by rolling. Production of satisfactory films by blow molding is not possible with these polyesters. Adhesives made from aliphatic/aromatic polyesters chain-extended with diisocyanates and crosslinked with polyisocyanates are disclosed in U.S. Pat. No. 3,804,810.
EP-A1-572 682 discloses that biodegradable films can be obtained from aliphatic polyesters which have, for example, been branched with pyromellitic dianhydride and chain-extended with polyisocyanates. Aliphatic/aromatic polyesters chain-extended with diisocyanates and capable of biodegradation are disclosed in DE-A1-44 40 858.
The biodegradable polyesters disclosed to date do not yet meet all requirements, in particular for producing films. In addition, the aliphatic polyesters show, although chain-extended and branched, a tendency to stick. Furthermore, they have the disadvantage that their melting points are too low and thus they have inadequate heat resistance. It is true that succinic acid can be employed to raise the melting points. However, this dicarboxylic acid is too costly fo
REFERENCES:
patent: 2999851 (1961-09-01), Elmer
patent: 3553157 (1971-01-01), Dijkstra et al.
patent: 3804810 (1974-04-01), Fryd
patent: 5446079 (1995-08-01), Buchanan et al.
patent: 5484861 (1996-01-01), Ihm et al.
Bauer Peter
Beimborn Dieter Bernhard
Bruchmann Bernd
Faller Uwe
Kowitz Christoph
Acquah Samuel A.
BASF - Aktiengesellschaft
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