Aldehyde emission reduction for dibenzylidene sorbitol clarified plastics

The present invention is generally related to clarifying agents or transparency enhancing agents used in conjunction with polyolefin resins, such as polypropylene. More specifically, the present invention includes an additive that is used in conjunction with certain dibenzylidene sorbitol-type (DBS) clarifiers within polyolefin resins to reduce the release of aldehydes formed as a result of the use of such clarifying agents. An additive that is used in conjunction with certain dibenzylidene sorbitol-type (DBS) clarifiers and acid scavengers within polyolefin resins to reduce the release of aldehydes from polypropylene material is disclosed. Hydrazides have been shown to be effective at removing residual aldehyde from polyolefins, such as polypropylene. This function can be accomplished with a minimal impact on optical transparent properties imparted to the polypropylene by the clarifying agent. The net effect is an improvement in the organoleptic performance of resins containing clarifiers, and a reduction in the UV-absorbing extractables. Particularly, adipic dihydrazide, when co-compounded into polypropylene homopolymer with 4-methyl DBS, improves the organoleptic performance of the clarifier. Incorporation of dihydrazides into polypropylene pellets reduced air-released aldehyde by nearly 100%.