| 摘要 |
PURPOSE:To decrease binding force of furan resins and to improve the collapsing property of molds by compounding >=1 kind amount phosphates, phosphites, phosphonates and phosphines with urea-modified furan resins. CONSTITUTION:A urea-modified furan resin is obtd. by using 0.5-5mol urea and 0.1-1.0mol formaldehyde per 1.0mol furfuryl alcohol and cocodensating these with acidity or alkalinity. At least >=1 kind selected among orthophosphates such as trimethyl phosphate, phosphites such as trimethyl phosphite and phosphines such as diphenyl phosphines are compounded with 100pts.wt the urea- modified furan resin. The reasons for limiting the urea and formaldehyde lie in that the binding force of the furan resins is made adequate. |
