U.S. Pat. No. 6,171,654 describes preparing fiberglass insulation using a water soluble or water-dispersible curable polyester resin binder formed by reacting a polyol, such as pentaerythritol, a terephthalate polymer, such as recycled polyethylene terephthalate (PET), a polyacid, such as isophthalic and terephthalic acid, an end (mono-functional) acid, a reactive diluent (crosslinker) such as a m