| abstract |
The present invention relates to a method for preparing a rigid polyurethane foam, comprising the steps of emulsifying the nucleating agent with a polyol and foam stabilizer, and at least any one of the water, catalyst, and blowing agent before the emulsifying step, during the emulsifying step, and after the emulsifying step. Mixing in one to prepare a polyol mixture, and reacting the polyol mixture with a polyisocyanate. Thereby, the size of an independent bubble can be made small and the rigid polyurethane foam which is excellent in heat insulation effect can be manufactured. |