Patent ID: 7750078

Claim:
A process comprising: a) combining to form a reaction mixture (i) a first reactant comprising a molten copolymer of propylene and 1-hexene comprising at least 50 mol % of propylene where the copolymer has a branching index (g′) of 0.95 or less measured at the z-average molecular weight (Mz) said polymer having a weight average molecular weight of less than or equal to about 100,000 g/mol, a crystalline peak melting point (T m ) of between 40-130° C., and a melt viscosity of less than or equal to about 40,000 cPs at 190° C.; (ii) an initiator comprising an organic peroxide having a decomposition half-life of less than about 30 minutes at the temperature of said reaction mixture; and (iii) a second reactant comprising an unsaturated carboxylic acid-based functionalizing agent, wherein the aliquots of initiator are completely added to the reaction mixture all at once and wherein the aliquots of the second reactant are added to the reaction mixture over a time interval equal to from about 1.5 to about 2.5 times the half-life of the organic peroxide and wherein the combining step comprises sequentially adding to the first reactant alternating aliquots of first the initiator and then the second reactant with addition of each such aliquot timed to allow the reaction mixture resulting from said aliquot addition to react for a time interval equal to from about 80% to 120% of the half-life of the organic peroxide after complete addition of each such aliquot before the next aliquot is added, b) maintaining the resulting reaction mixture at a temperature of 130° C. to form a reaction product comprising acid-grafted propylene-based polymeric material, and having a Grafting Efficiency of at least about 70% and a Gardner Color Index of less than about 4; and c) using the reaction product in a hot melt adhesive.