| abstract |
Polyols with at least one primary hydroxy function and at least one other primary, secondary or tertiary hydroxy function in the 2 and/or 3 position are used as additives in concentrations from 50 ppm to 5,000 ppm in order to reduce the acetaldehyde content of extruded products of polyetheylene terephthalate. Sugar alcohols, such as sorbitol, mannitol or xylitol, are preferably used. Additionally, ionic compounds, preferably easily soluble ionic compounds, such as alkali compounds, can be admixed in amounts from 0.05 ppm to 50 ppm. According to the present invention, aqueous polyol solutions are sprayed onto polyethylene terephthalate pellets after polycondensation or after the second polycondensation stage, also known as solid state polymerization, or said pellets are produced through extrusion with a polyol content of less than or equal to 25 percent by weight, pelletized, and admixed as a masterbatch with a polyester prior to processing. |