c emulsification was conducted in the same manner as in example 1 except for changing the sizing ingredients 3 and 4 in example 1 a to those given in the following table to measure the amount of precipitated particles of the emulsions table 1______________________________________ run no no 1 no 2______________________________________compound 3 used in 10 parts 0 partexample 1compound 4 used in 0 part 10 partsexample 1amount of precipitated 9 92 emulsion particles______________________________________ further carbon fibers were treated with the composition of run no 1 in the same manner as in example 1 b and a cfrp bar was prepared therefrom this cfrp bar showed an ilss value of 9 8 kg mm 2 at room temperature and 6 8 kg mm 2 in 80 u00b0 c air from these results it is seen that sizing agents not containing either of the compounds i or ii formed a large amount of an emulsion particle precipitate thus lacking emulsion stability leading to low ilss of cfrp and adversely affecting physical properties of cfrp emulsions and cfrp bars were prepared in the same manner as in example 1 except for changing the sizing agent ingredients 3 and 4 to a popularly known surfactant noigen ea 190 trade name of polyethylene glycol adduct of 25 moles of ethylene oxide lauryl ether made by dai ichi kogyo seiyaku co ltd these were tested in the same manner as in example 1 with respect to the same items to obtain the results shown in table 2 from the results given in table 2 it is seen that the use of the conventionally used surfactant provided inferior results to those in example 1 with.