second polymer with a relatively high solubility parameter such as polystyrene and poly and a block copolymer containing blocks of the first and second or other structurally similar constituting monomeric units examples of the block copolymers include ethylene styrene copolymer propylene styrene copolymer and isoprene styrene copolymer etc the binder composition is dispersed in an appropriate dispersant such as an oil or wax then blended with a metal powder to form a metal powder injection composition the metal powder injection composition forms a green compact with a predetermined shape and dimension using an injection molding machine finally the green compact is sintered to form the final product the present binder composition eliminates the incompatibility problem which is often encountered when using multi component binders this allows the green compact to maintain excellent dimensional and physical integrities both before and during the sintering step and thus ensures the precise dimension of the final products application_number US 28836794 A description the present invention discloses a binder composition which comprises 1 a first polymer having a relatively high crystallinity and low solubility parameter 2 a second polymer having a relatively low crystallinity and high solubility parameter and 3 a block copolymer containing blocks of the constituting monomers of the first and second polymers or of monomers of respectively similar structures in the binder composition disclosed in the present invention the block copolymer serves as a solubilization aid causing the first and the second polymers to be mutually miscible to thereby form a homogeneous liquid mixture as discussed below the first polymer is preferably polypropylene the second polymer is preferably polystyrene and the copolymer is preferably a copolymer.