Flexible foam has limited flexible and reshaped properties with open cell structures. It is known as sponge by public. Low density foam (13-40 kg/m3) is produced in continous line by slabstock technology. High density foam is produced in discontinue line by molding. In molding technology polyol and isocyanates are injected by injection machine. As a result of reaction, the foam takes the shape of the mold with a flexible structure. The prepolymer isocyanates are used in this reaction are TDI or MDI based. If polyol systems are not used with the right isocyanates, there can be some technical problems or desired foam cannot be obtained. Semi flexible or memory foam (visco) are in this type. Today with developing technologies, the desired foam with  various hardness, flexibility and density can be produced easily.