30 min 1800 s was measured with 1000 psig 6 89 kpa nitrogen pressure on the filtration cell the fluid loss measure was then multiplied by 2 so as to adjust for the size of the screen used with the filtration cell polyamine 300 503 5 g and 825 5 g of water were placed in a 1 liter vessel the temperature of the solution was controlled at 30 u00b0 c while 1858 g of epichlorohydrin was added the reactants were stirred at 70 u00b0 c overnight and an amber product was removed from the flask crosslinker solution prepared in a above 10 3 g was added to 150 g of polyalkylenepolyamine prepared as in example 1 a the mixture of reactants was heated at 60 u00b0 70 u00b0 c for 4 hours 14400 s an amber solution was removed from the vessel it was tested as a fluid loss additive by the procedure described in example 1 d the results are given in table i to 300 g of polyalkylenepolyamine prepared in example 1 a was added 8 g of epichlorohydrin the mixture was reacted in a 60 u00b0 c shaker both overnight an amber solution was produced this material was tested according to example 1 d the results are given in table i to 250 g of polyamine 300 was added 640 g of water epichlorohydrin.