Abstract: A curable polymer containing one or more type(s) of structural units (UX) represented by the following formula and which is for production of a prepreg, a metal clad laminate or a wiring board: in which X is a single bond or an oxygen atom; the benzene ring optionally has a substituent other than the substituent in the above formula; and n is an integer of 0 or more.

Abstract: An ion generator can generate clean ionized gas, in which no foreign matters are mixed, and apply the same to a treated object. Ultraviolet rays from an ultraviolet generating source 15 are irradiated to a photo receiver 11a provided with a coating layer 14 made of titanium oxide, and air surrounding the photo receiver is electrically separated to generate positively charged particles and negatively charged particles. An electric field is created by the electrode 17 in a space containing the electrically separated air to ionize the charged particles. The ionized charged particles are blown toward the treated object W by a blower 20.