The characteristic of RIM process is the material flow rate is very high .Then stoste's viscosity can not be very high .Such as the viscosity of polyurethane mixture is about 0.1 Pa s.and flow rate control at 600 g/s in mold falling .
Polyurethane two-component mixture have very high reactivity after injected in the mold ,so it complete curing in ten more minutes .But plastic's conductivity is not good , so most heat can not release from a large chemical reaction condition , so that the outside temperature are higher than inside, so the curing development is from inside to outside .
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