Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Patent
1997-11-24
1999-12-28
Szekely, Peter A.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
523128, 524211, 524386, 524591, C08L 302, C08L 7500, C08K 521, C08K 5053
Patent
active
060082763
DESCRIPTION:
BRIEF SUMMARY
The invention relates to thermoplastically processable and biodegradable, starch-containing polymer blends, a process for their production and their use for producing mouldings, films, fibres, coatings or laminates by thermoplastic processing.
The property profile of thermoplastically processable starch can be improved and optimized by mixing the starch, e.g. during an extrusion process, with synthetic polymers.
Suitable polymers for this purpose are, in particular, hydrophilic polymers such as polyvinyl alcohol or cellulose ethers (DE 4 237 535) or ionic polysaccharide derivatives or ionic polymers (U.S. Pat. No. 5,095,054). In addition, the patent literature describes a wide variety of blends of starch with organic mixing components, in particular plastics such as polyurethanes, polyamides, polyesteramides, polystyrene, polyacrylonitrile, polyacrylates and the like (cf. for example WO 94/03543, WO 92/19680, DE 4 038 732, and also the European patent applications published under the numbers 536 679, 409 783, 409 788, 409 789, 407 781, 408 501, 408 502, 408 503, 407 350, 404 723, 404 728 or 327 505).
The biodegradability of starch-containing polymer blends requires that all constituents of the blend are biodegradable. However, it is known that the conventional polymers having a continuous C--C linkage are, with the exception of PVA, not biodegradable (cf. for example Agricultural and Synthetic Polymers, Biodegradability and Utilization, ASC Symposium Series 433, 1990, page 6, edited by J. S. Glass and G. Swift). The commercially available polyamides and most of the known polysaccharide derivatives are also not biodegradable.
However, examples of biodegradable blending partners for starch are poly-.epsilon.-caprolactone, polyhydroxybutyric acid-valeric acid copolymers or polylactide-glucolide copolymers (DE 4 237 535). These polymers are, however, hydrophobic substances which can be combined with the starch to give the polymer blend only with concomitant use of phase compatibilizers or of further hydrophilic polymers.
It was therefore an object of the invention to provide new, thermoplastically processable and biodegradable, starch-containing polymer blends which can be thermoplastically processed to give end products having good mechanical properties and can be produced by combining the starch with aqueous dispersions of self-emulsifiable plastics.
This object was able to be achieved by means of the polymer blends described in detail below or by means of the process for their production.
The invention provides thermoplastically mouldable, biodegradable, starch-containing polymer blends consisting essentially of urea and/or at least one polyhydric alcohol of the molecular weight range from 62 to 400 and component B) comprises polyurethanes containing urea groups which have been prepared by known methods, with the equivalence ratio of isocyanate groups to groups capable of reacting with isocyanate groups being from 1:1 to 2:1, from weight, based on the mixture, of 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane and/or 4,4'-diisocyanatodicyclohexylmethane and/or 1-methyl-2,4(6)diisocyanatocyclohexane together with the hydroxyl group content of from 500 to 10,000 from (i) adipic acid and/or succinic acid and (ii) at least one alkanediol having from 2 to 6 carbon atoms or on the total weight of the component b), of alkanediols having from 2 to 6 carbon atoms and optionally containing ether groups, the total amount of the groups capable of reacting with isocyanate groups and present in the components b) and c), comprising the total weight of the component c), of ethylenediamine, optionally components b), c) and d), and optionally of isocyanate groups to groups capable of reacting with isocyanate groups, atoms, and 4000, whose alkylene oxide units comprise at least 40% of ethylene oxide units and the remainder are propylene oxide units.
The invention also provides a process for producing such polymer blends by mixing the individual components at from 80 to 150.degree. C. in plastics processing machine
REFERENCES:
patent: 3004934 (1961-10-01), Dosman et al.
patent: 3639309 (1972-02-01), Starkman
patent: 5095054 (1992-03-01), Lay et al.
patent: 5412005 (1995-05-01), Bastioli et al.
patent: 5436078 (1995-07-01), Buhler et al.
patent: 5439953 (1995-08-01), Ritter et al.
patent: 5543494 (1996-08-01), Perego et al.
Agricultural & Synthetic Polymers, Biodegradability & Utilization, ASC Symposium Series 433, 1990, pp. 3-13, edited by J.S. Glass & G. Swift.
Kalbe Jochen
Koch Rainhard
Muller Hanns-Peter
Bayer Aktiengesellschaft
Szekely Peter A.
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