Process for production of polyester polyoles by using of terephthalate waste materials and their application for producing PUR foams

摘要

A process for the production of polyester-polyols (I) based on phthalic anhydride (PAA), polyhydric di-alcohols and waste polyethylene or polybutylene terephthalate (PET or PBT) fibre, optionally combined with waste PET bottle material. In this process, (a) no additional transesterification catalyst is added if titanium dioxide-pigmented fibre is used, (b) trans- esterification and simultaneous esterification are carried out at 200-250 degrees C, (c) low-mol. wt. alcohols in a concentration of 0.01-0.1 wt% and PAA are added at the start of esterification, (d) the final product shows a density in the same range as the solvated metal compounds and a viscosity of more than 2000 mPa.s at 20 degrees C, and (e) the product is processed directly to polyurethane (PUR) foam by reaction with di-isocyanate without adding catalyst.