Process for the production of a wiping material for a vacuum chamber

摘要

The present invention provides a wiping material for a vacuum chamber having sufficient sludge wiping properties and water retention attained by easy control over cell diameter and use of a polyurethane foam which has been foamed free from a silicone-based surface active agent and a process for the production thereof. A wiping material made of a polyurethane foam for a vacuum chamber for use in the preparation of a silicon wafer is described, wherein the polyurethane foam is free of silicone and has an open-cell structure comprising cells the diameter of which are controlled to fall within the range of from 500 mum to 3,000 mum.