| 摘要 |
PROBLEM TO BE SOLVED: To provide a cashew novolac resin having further excellent heat resistance and strength, a method for preparing the resin, and a curing agent for an epoxy resin, the agent containing the above cashew novolac resin. SOLUTION: The cashew novolac resin is obtained by reacting a cashew nut shell liquid with, if necessary, other phenolic resins and aldehydes in the presence of a weak acidic catalyst, and has a number average molecular weight of not less than 2,000 and a melt viscosity of not more than 500 mPa s at 150°C. Upon sequentially adding aldehydes to the cashew nut shell liquid, it is preferable to carry out the reaction while removing the water content in the system. The cashew novolac resin is effective as a curing agent for an epoxy resin. COPYRIGHT: (C)2009,JPO&INPIT |
