Reclaimed poly (ethylene terephthalate) coating
AssigneeSun Chemical Corporation
InventorsSubhankar Chatterjee, Albert A. Kveglis, Neil Young, Robert Kern, Thomas F. O'Malley, Bhalendra J. Patel
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Abstract
An organic oligomer binder produced by depolymerizing virgin, scrap, recycled or reclaimed polyethylene terephthalate via an alcoholysis reaction with branched glycols and esterifiing the resulting polyol oligomer with polybasic carboxylic acids and/or anhydrides.
Claims22
A polyethylene terephthalate oligomer having a number average molecular weight of about 850 to 5000, a weight average molecular weight of about 4,000 to 25,000 and an acid value about 5 to 50 mg KOH per gram comprised of about 40 to 70 weight percent recurring ethylene terephthalate units, recurring units of C.sub.3.sup.+ alpha alkylene terephthalate, hydroxy alkylene terephthalate and pendant units of polybasic aliphatic, alicyclic or aromatic monocarboxylate.
A process for converting poly ethylene terephthalate polymer into binder resin having an acid value between 5 and 50 mg KOH/g comprising:
- a) reacting PET particles with between 3 and 25 weight percent of a mixture of C.sub.3.sup.+ 1,2-alkylene glycol and polyhydric aliphatic alcohol in a weight ratio of 1:2 to 1:5, respectively in the presence of an alcoholysis catalyst for a time sufficient to convert said polymer into an oligomeric PET polyol;
- and
- b) contacting said oligomer with about 5 to 40 weight percent of a polybasic aliphatic, alicyclic or aromatic organic acid or acid anhydride under esterification conditions.
A polyethylene terephthalate oligomer comprising between 40 and 70 weight percent recurring ethylene terephthalate units having the structure:
- ##STR3## wherein R.sub.3 is alkyl;
- R.sub.1 and R.sub.2, alike or different, are hydrogen, aliphatic, alicyclic or aromatic carbonyl or carboxy carbonyl;
- x is an integer of 1 to 20, and y and z are integers of 1-10.
Dependencies are inferred from the claim text.