Kraton G series 1657 rubber is used as an additive to low molecular weight resins such as Regalrez 1094. When using Kraton rubber always be sure to use Tinuvin 292. The rubber improves the flexibility of a final varnish, improves scratch resistance and increases the varnishes viscosity which yields a better feeling varnish when applying by brush (low molecular weight resins tend to feel very thin). Kraton G 1657 can be added in the range of 1-3% by weight of resin. One helpful hint, Kraton rubber does not dissolve well in low aromatic solvents, try pre-dissolving the Kraton rubber in a small amount of high aromatic solvent such as xylene.