摘要 |
PROBLEM TO BE SOLVED: To incorporate excellent heat insulation performance and to improve mechanical strength such as compression strength by holding conditions such as a constitution of a mixer and temperature and pressure in the mixer in specific ranges. SOLUTION: A mixer has a mixing unit A having an agitating unit for mixing resol with foaming agent, a mixing unit B similarly having an agitating unit for mixing resol and foaming agent with catalyst, and a distributing unit C for distributing mixture obtained via the units A and B to a desired shape. Pressure PA of the mixture of the unit A is larger than vapor pressure of the agent at a temperature TA of the unit A. Temperature TB and pressure PB of the mixture at an outlet of the unit B satisfy 30 deg.C<=TB<=70 deg.C, Pmin<=PB<=Pmax (where Pmax: vapor pressure of the foaming agent at the temperature T, Pmin: 0.5×Pmax). |