Plastic and nonmetallic article shaping or treating: processes – Forming articles by uniting randomly associated particles
Patent
1997-11-04
1999-10-05
Niland, Patrick D.
Plastic and nonmetallic article shaping or treating: processes
Forming articles by uniting randomly associated particles
264165, 26417211, 26417713, 264178F, 264555, 428227, 428357, 524 47, 524590, 524591, 524839, 524840, 524507, B27N 300, B28B 1118, B29C 3914, B29C 4322
Patent
active
059619066
DESCRIPTION:
BRIEF SUMMARY
The invention relates to the use of aqueous dispersions of selected polyurethanes, containing urea groups, for the production of biodegradable and compostable shaped bodies, including sheet structures, optionally via the intermediate stage of granules prepared from the dispersions by spray drying.
Fully biodegradable and compostable plastics will in the future acquire ever greater economic and technical importance (T. Jopski, Kunststoffe 83 (1993) 10). The major challenge is to produce plastics which have the necessary functionality yet degrade under the stimulation of a biologically active environment. The initiating factor may be microbiological, hydrolytic or oxidative degradation at a specific site in the main chain of the polymer. All degradation products must be safe, non-toxic and non-accumulable in nature, i.e. must be subject to complete microbial degradation. To date, three general categories of the abovementioned materials have become known: polyester-like polymers, plastics based on naturally occurring polymers, and other degradable plastics, for example polyvinyl alcohol. The polyester-like polymers include polylactic acid, polyhydroxybutyrate, polyhydroxyvalerate, polycaprolactone and high molecular weight aliphatic polyesters (EP-A-0 572 256, 1993). In order to obtain sufficiently high molecular weights, the polyesters specified in EP-A-0 572 256 are extended with organic diisocyanates to form the end product. The use of thermoplastic poly-(esterurethanes) as compostable plastics is described in EP-A-0 593 975.
Biodegradable thermoplastic polyurethane filaments are described in DE-C-4 319 439. The thermoplastically processable polyurethanes are linear and, accordingly, have difunctional polyesterdiols and difunctional polyethylene glycols built into the polymer chain, and are built up using hexamethylenediisocyanate and butanediol or hexanediol as chain extenders (Examples 1 to 3, DE-C-4 319 439).
Degradable shaped bodies or sheet structures comprising polyurethanes which contain urea groups have not hitherto been disclosed. The use, according to the invention, as described below in more detail, of aqueous dispersions of selected polyurethanes which contain urea groups shows a simple route to such plastics.
The invention relates to the use of aqueous dispersions of polyurethanes which contain urea groups, optionally via the intermediate stage of granules obtained by spray drying the dispersions, for the production of fully biodegradable shaped bodies, including sheet structures, especially coatings on any substrates, characterized in that, as polyurethanes which are dispersed in water and contain urea groups, use is made of reaction products which are prepared by known methods, observing a ratio of equivalents of isocyanate groups to isocyanate-reactive groups of from 1:1 to 2:1, from
a) a diisocyanate component consisting of 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, with
b) a diol component consisting of calculated from the hydroxyl content, of from 500 to 10,000 of (i) adipic acid and/or succinic acid and (ii) at least one alkanediol having 2 to 6 carbon atoms, or total weight of component b), of alkanediols having 2 to 6 carbon atoms and optionally containing ether groups,
c) a diamine component in a quantity of from 2 to 50 equivalent-%, based on the total quantity of the isocyanate-reactive groups present in components b) and c), consisting of the total weight of component c), of ethylenediamine, and optionally
d) hydrophilic polyether alcohols of the general formula components b), c) and d), and also, optionally,
e) water, which is not included in the calculation of the ratio of equivalents of isocyanate groups to isocyanate-reactive groups, and to 4000, at least 40% of whose alkylene oxide units consist of ethylene oxide units while the remainder consist of propylene oxide units.
Aqueous dispersions of polyurethanes which contain urea groups and
REFERENCES:
patent: 4237264 (1980-12-01), Noll et al.
patent: 5061777 (1991-10-01), Yoda et al.
patent: 5310782 (1994-05-01), Takiyama et al.
patent: 5496909 (1996-03-01), Muhfeld et al.
T. Jopski, Biologisch abbaubare Kunststoffe 83 (1993) 10.
Kalbe Jochen
Koch Rainhard
Muller Hanns-Peter
Bayer Aktiengesellschaft
Brown N. Denise
Gil Joseph C.
Niland Patrick D.
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