Process for continuously producing polyester articles with scrap recycle in a continuous melt-to-preform process
AssigneeEastman Chemical Company
InventorsMichael Paul Ekart, Max Lamar Carroll, Jr., Eric Gray Olsen, Lanney Calvin Treece
Life of this patent
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Abstract
A process for producing polyester articles, which generates little or no polyester waste. The process provides esterification or transesterification of one or more dicarboxylic acids or their dialkyl esters, polycondensation to produce a high molecular weight polyester, and molding or shaping of the polyester for produce the desired product. Scrap produced during the molding process is recycled back to the esterification or transesterification or polycondensation portion of the process. Optionally, the scrap may also be recycled to intermediate steps prior to the molding operation.
Claims19
A process for the continuous production of shaped molded polyester articles which comprises:
- a) reacting dibasic acid and glycol precursors of polyester homopolymer or copolymer in a reactor under
- i) esterification or transesterification conditions, followed by
- ii) polycondensation conditions,
- thereby producing a stream of molten polyester homopolymer or copolymer;
- b) flowing the stream of molten polyester into at least one molding apparatus and forming solid molded articles and polyester scrap therefrom without solidifying the polyester prior to entry into the molding apparatus;
- c) separating the polyester scrap from the solid molded articles;
- and
- d) recycling the polyester scrap to step (a) by adding it to the stream of molten polyester homopolymer or copolymer or their precursors.
Dependencies are inferred from the claim text.