Large size, sensitive response thermally expandable microspheres for the manufacture of suede‐like leather

Abstract A large size, sensitive response thermally expandable microspheres (TEMs) for suede‐like leather manufacture was prepared by suspension polymerization using acrylonitrile (AN), methyl methacrylate (MMA) and vinyl acetate (VAC) as the shell monomers and iso‐pentane as the foaming component. The effect of the interfacial tension and viscosity of polymerization system on the particle size of TEMs, and in turn, the effect of the particle size of TEMs on the expansion temperature, expansion ratio and thermal response performance were investigated in detail. The results showed that increasing the interface tension and viscosity of the polymerization system was beneficial for preparing large size TEMs. Under the optimized conditions of 300 rpm, 25 wt% iso‐pentane dosage, and 9:3:1 mass ratio of AN/MAA/VAC, the TEMs shown above 100 μm particle size and 4 times expansion ratio at 150°C. Moreover, TEMs with 18% encapsulation ratio ( E r ) of the foaming component can complete foaming in the narrow temperature range (Δ T ≤ 10°C), showing a sensitive thermal response. The mixture of waterborne polyurethane and quantitative TEMs was coated on the surface of synthetic leather base, and a new type of suede‐like leather was obtained after foaming, which can substitute genuine suede leather.