Jerome S Schaul

US Patent:

42231280, Sep 16, 1980

Filed:

May 16, 1978

Appl. No.:

5/906393

Inventors:

George W. Halek - Summit NJ
William T. Freed - Madison NJ
Jerome S. Schaul - Caldwell NJ
Raymond W. Rupp - Greenville SC
Stanley L. Pauls - Taylors SC

Assignee:

Celanese Corporation - New York NY

International Classification:

C08G 6322

US Classification:

528481

Abstract:

There is disclosed a process for reducing the acetaldehyde content and the generation rate of acetaldehyde of polyethylene terephthalate chip which has a crystallinity of at least about 30% in order to render the polyethylene terephthalate suitable for making containers which are useful in the carbonated beverage industry. This process comprises stabilizing the polyethylene terephthalate by heating it at an elevated temperature in air and maintaining an air to chip ratio at a predetermined value of at least about 0. 8 standard cubic foot of air per minute/pound of resin per hour and at a vapor velocity of at least about 0. 5 foot per second. The air used in the stabilization process has a dew point of less than about -30. degree. C. The stabilized polyethylene terephthalate produced by this process has an acetaldehyde level of less than about 2. 5 parts per million, a generation rate of acetaldehyde of less than about 3.