Patent ID: 6669407
Filing Date: 2003-12-30
Classification: C08G

Abstract:
A polyurethane geotextile composite liner comprising a geotextile impregnated with a water resistant polyurethane which is a reaction product of a mixture comprising:a) a liquid polyisocyanate having an isocyanate content of at least 10% by weight, b) an isocyanate-reactive component comprising: (i) 20 to 90% by weight, based on total by weight of b), of castor oil having an OH number of from about 160 to about 170, a viscosity of about 500 to about 900 mPaÂ·s at 25Â° C., and a water content of less than 0.5% by weight, based on the weight of castor oil; (ii) 10 to 80% by weight, based on total weight of b), of a polyether polyol having an OH number of from 28 to 700, a functionality of from 2 to 8, a number average molecular weight of from about 240 to about 6,000, and a viscosity of from 50 to 35,000 mPaÂ·s at 25Â° C., The polyether polyol being the reaction product of an initiator compound with an alkylene oxide of which at least 70% by weight is propylene oxide; and (iii) from 0 to 10% by weight, based on total weight of b), of a low molecular weight diol or triol having an equivalent weight of from 31 to 99; c) a catalyst which catalyzes the reaction between hydroxyl groups and isocyanate groups; and optionally, d) a filler, wherein said polyurethane geotextile composite liner has improved water resistance, and wherein said improved water resistance comprises a water absorption at 24 hours with a maximum value of about 0.4% or less and said liner is suitable as a ditch or canal liner.