Patent ID: 7670517

Claim:
A method of producing a polyurethane foam sheet, comprising the steps of applying a liquid mixture, obtained by mixing together a heated and melted hot melt urethane prepolymer (A), with a number average molecular weight within a range of 1,000 to 10,000 and containing isocyanate groups at molecular terminals, and a diol (B), onto a substrate in a sheet-like manner, and water foaming said liquid mixture by bringing said sheet-like liquid mixture into contact with water vapor by spray misting, wherein a ratio of a weight equivalence of active hydrogen atom-containing groups within said diol (B), relative to a weight equivalence of isocyanate groups within said hot melt urethane prepolymer (A) [isocyanate group equivalence/active hydrogen atom-containing group equivalence], is within a range of 1.5 to 20.0, the atmospheric temperature at the surface of the sheet-like liquid mixture is set to a temperature within a range of 40 to 120° C. the atmospheric humidity is set to at least 60%, and the humidification time period is set to a value within a range of 0.5 seconds to 10 minutes, and the foaming degree of the polyurethane foam sheet is within a range of 1.5 to 3.0.