... Grade HT-10HT-13HT-23 Number Average Molecular Weight Mn1,0001,3002,300Distribution≤2.0≤2.0≤ ... 4≤4Na.K.Fe ppm222Food Grade GradeViscosity Average Molecular Weight MvDistributionStaudinger IndexVolatiles 150°C 2hwt%Heavy metal(pb) ... .0≤0.5≤10.0≤0.5≤10,000≤30365,000130,000HT-95095,0003.446.0-52. ... 5≤10,000≤30604,000240,000Industrial Grade And so on . PIB polyisobutene Lower ,middle and high weight PIB ,made ...