| 摘要 |
PURPOSE:To obtain a mulching sheet which has moderate gas permeability and prevents the evaporation of soil moisture, the elevation or falling of ground temperature and the escape of soil, by expanding and curing a composition comprising a hydroxyl group-containing liquid diene polymer and a polyisocyanate compound. CONSTITUTION:A composition is obtained by mixing 100pts.wt. hydroxyl group- containing liquid diene polymer (A) having a number-average MW of 300-25,000 and a hydroxyl group content of 0.1-10meq/g with a polyisocyanate compound (B) (e.g., diphenylmethane diisocyanate) in an amount to provide a molar ratio of the isocyanate groups to the hydroxyl groups of component A (NCO/OH) of 0.25-25, 1-1,000pts.wt. polyol compound (e.g., 1,2-propylene glycol) of a MW of 50-500 and/or polyamine compound (C) (e.g., hexamethylenediamine) and a blowing agent. This composition is poured into a molding frame and is expanded and cured to obtain a mulching sheet having 0.1-1.0mm fine cells. |
