| abstract |
(57) [Problem] To provide a switch and the like, a small air hole is opened in a case in order to discharge corrosive gas such as nitric acid generated when opening and closing a contact. When foreign matter such as the like enters, it adheres to the contact and the like, and the switch may malfunction. SOLUTION: A photosensitive composition 6 is formed in an air hole 5 of a case 2. a is applied and cured by irradiating electromagnetic waves, A porous coating film 6 having air permeability was formed in the air hole 5. The photosensitive composition 6a has a photopolymerizable monomer, a substance that is incompatible with the photopolymerizable monomer, and is soluble in both the photopolymerizable monomer and the incompatible substance. A liquid containing a common solvent and a photopolymerization initiator for curing the photopolymerizable monomer by electromagnetic wave irradiation, and is cured by irradiation with ultraviolet light to obtain a porous film having air permeability. |