Celanese Gmbh

George W Halek

Raymond W Rupp

John S Gall

Jerome S Schaul

Stanley L Pauls

William T Freed

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 3.0 parts per million per minute and an intrinsic viscosity of from about 0.60 to about 0.95 deciliters per gram. There is also disclosed a process for molding a polyethylene terephthalate preform comprising melting the above described polymer, forming it into the desired preform shape, and cooling the molten polymer. This preform may then be reheated above its glass transition temperature and molded into the desired container shape.

Process for preparing polyethylene terephthalate useful for beverage

Blow molded polybutylene terephthalate articles and a process for making them. A polybutylene terephthalate melt at a temperature in the range of the melt temperature of polybutylene terephthalate and 495.degree.F., and having an intrinsic viscosity of at least 1.05 deciliters per gram is blow molded in an extrusion blow molding apparatus the mold of which is maintained at a temperature of less than 150.degree.F. to produce polybutylene terephthalate blown articles possessing excellent strength characteristics. Bottles, especially aerosol pressurized bottles, are a primary application of the type of articles produced by this process.

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Summit, NJ, United States of America

George W Halek