Abstract: A method to purifying reclaimed polymers for improving the grade and consistency in the properties of mixed recycled plastic to increase their use in secondary applications. A desired property of the purified reclaimed polymer is determined with a first parameter value of a reclaimed polymer feedstock also determined to provide the desired property in the purified reclaimed polymer. Ratios of polymer feedstocks with differing parameter values are combined to give the first parameter value. These polymer feedstocks are then dissolved into a solution before the purer polymer with the desired property is separated out. Embodiments of reactor vessels for the dissolution step are described. Polyethylene feedstocks can be used with parameters of density and molecular weight to provide high grade polyethylene with desired physical and mechanical properties such as density, molecular weight, strength, stress, stiffness and impact resistance.

Abstract: A method for the fractionation of reclaimed polymer in at least one solvent in a process for purifying reclaimed polymers plastic recycling to increase their use in secondary applications. The reclaimed polymer is dissolved in a solvent within a reactor vessel having a stack of perforated discs which are oscillated. The linear motion of the stack speeds up dissolution time to minutes rather than hours and the required polymer to solvent ratio can be increased to 0.3 to 10% wt addition. Temperature and time effects are used to fractionate polymers of differing molecular weights to provide purified and graded plastics for secondary use at a commercially viable scale.

Abstract: A method to purifying reclaimed polymers for improving the grade and consistency in the properties of mixed recycled plastic to increase their use in secondary applications. A desired property of the purified reclaimed polymer is determined with a first parameter value of a reclaimed polymer feedstock also determined to provide the desired property in the purified reclaimed polymer. Ratios of polymer feedstocks with differing parameter values are combined to give the first parameter value. These polymer feedstocks are then dissolved into a solution before the purer polymer with the desired property is separated out. Embodiments of reactor vessels for the dissolution step are described. Polyethylene feedstocks can be used with parameters of density and molecular weight to provide high grade polyethylene with desired physical and mechanical properties such as density, molecular weight, strength, stress, stiffness and impact resistance.

Abstract: A method to dissolve a polymer in a solvent in a process for the removal of additives in plastics, in which the polymer and solvent are combined in a reactor vessel having a stack of perforated discs which are oscillated. The linear motion of the stack speeds up dissolution time to minutes rather than hours and the required polymer to solvent ratio can be increased to 0.3 to 10% wt addition. The reactor vessel can be heated with pressure remaining at atmospheric. The method lends itself to commercial scale processing with reactor vessels of 1,000 litres and greater.