naps such that all the spaces between the naps are at least partially not filled thus allowing the film to have air permeability as a result as shown in the images of fig6 a and 6b it is possible to produce synthetic leather having properties similar to the air permeability and surface texture of genuine leather for example if the amount of water soluble pu resin solution applied is less than about 50 g m 2 most of the resin solution penetrates the spaces between the naps which make it difficult to form a uniform film on the nap thus degrading the texture of the film moreover if the amount of pu resin solution applied exceeds about 60 g m 2 a uniform film can be formed on the nap to improve the texture of the film however the thus formed film covers the spaces between the naps which make it difficult to ensure the space thus reducing the air permeability thus the most preferable range is in between 50 g m 2 and 60 g m 2 of pu resin these results were obtained by examining the differences in air permeability and texture through various examples example 1 to 3 and comparative examples 1 to 3 performed by varying the amount of thermosetting resin solution applied in the film forming process s 4 of the method for producing synthetic resin in which the softening process s 1 the brushing process s 2 the back reinforcing process s 3 and the film forming process s 4 are sequentially performed and the results are shown in the following table 1 here the air permeability was evaluated by cutting the synthetic leathers produced in.