Baybond PU 402A Aliphatic polyester urethane Bayer MaterialScience Polyurethane (PU) - Polyurethane dispersions (PUDs) >> Polyester Baybond PU 402A is an anionic dispersion of an aliphatic polyester urethane resin in water/toluene. Baybond PU 402A polyurethane dispersion is useful for the sizing of glass fibers used to reinforce thermoplastics. The dispersion displays excellent mechanical stability. As with any product, use of Baybond PU 402A polyurethane dispersion in a given application must be tested (including but not limited to field testing) in advance by the user to determine suitability. Anionic dispersion of an aliphatic polyester urethane resin. Offers very good mechanical stability.