Optically transparent pressure-sensitive adhesive sheet, laminate, process for producing laminate, and display device with touch panel

An optically clear adhesive sheet consisting of:

• a cured product of a heat-curable polyurethane composition,
• the heat-curable polyurethane composition containing a polyol component and a polyisocyanate component, wherein the heat-curable polyurethane composition does not contain an tackifier,
• the polyol component consisting of a polyol having an olefin skeleton, wherein the polyol having an olefin skeleton is the only polyol component in the heat-curable polyurethane composition,
• the polyisocyanate component containing at least one of an acyclic aliphatic polyisocyanate, an alicyclic polyisocyanate, a modified acyclic aliphatic polyisocyanate and a modified alicyclic polyisocyanate, wherein
• the modified acyclic aliphatic polyisocyanate is obtained by reacting an acyclic aliphatic polyisocyanate having an isocyanate group with an ether compound having an ethylene oxide unit,
• the modified alicyclic polyisocyanate is obtained by reacting an alicyclic polyisocyanate having an isocyanate group with an ether compound having an ethylene oxide unit, and wherein
• an α ratio (A/B) of the number of moles of OH groups (A) derived from the polyol component to the number of moles of NCO groups (B) derived from the polyisocyanate component is 1.3 to 1.8.