Optimization of Exothermic, Foaming, and Mechanical Properties of Modified Polyurethane as Filling Material for Goaf Sealing Wall

Table 4

Physical and chemical properties of component A, component B, and their mixture.

Properties	Component A	Component B	Mixture by mass ratio
Color	Brown	Opaque	Brown
Density (g·cm^−3)	1.022	1.203	1.119–1.143
Gel time (s)			57–73
Curing time (min)			9–13
Viscosity @ 25°C (MPa·s)			253–298