herein by reference the process involves applying to the down feathers an aqueous emulsion of a curable zirconium acetate and curing said polymer the emulsion can be applied by exhaustion for example the feathers are thoroughly cleansed prior to application of said copolymer which can be accomplished by means of a water wash followed by partial water removal so as to leave a residual moisture content of 5 to 45 based on the weight of completely dry feathers the copolymer can be cured at 130 degrees to 170 degrees c alternatively the water repellent properties for down natural fibers can be imparted using different techniques which are not just limited to wet bath or dry spraying processes various surface energy modification techniques which are well known in the art such as plasma treatment can also be employed to treat the down clusters for providing water repellent properties such treatments or processes arc explained in u s pat no 4 869 922 u s pat no 5 262 208 u s pat no 5 895 558 u s pat no 6 416 633 u s pat no 7 510 632 u s pat no 8 309 033 and u s pat no 8 298 627 the entire contents of which is incorporated herein by reference the preferred short cut synthetic man made fibers.