摘要 |
A heat exchanger is immersed in a hydrophilic-film-forming solution in order to form a hydrophilic film on the surface of the heat exchanger. The film applied on the heat exchanger is then dried to a semi-dry state and while this film is semi-dry, an antimicrobial agent is permeated into the hydrophilic film. Then it is completely dried. By following this process, it is possible to permeate a large amount of antimicrobial agent near the surface of the film, increasing the antimicrobial effect and at the same time, the effect is retained over a long period of time because the antimicrobial agent is not coated on the surface and, therefore, is not washed away with water. |