Formaldehyde → Benzoxazines

Participants

Reaction Conditions

Reaction Steps

The steps include: in a 2 L four-necked glass reactor equipped with a heating mantle, a temperature controller, an electric mixer and a condenser, 350 g of phenolic resin (C) having high proportion of tri-functional resin monomer and 246 g of paraformaldehyde are dissolved thoroughly in the presence of 816 g of a solvent propylene glycol monomethyl ether at 85° C., 334.4 g of aniline is dropped in the course of 3 hours into the reactor at constant speed by a quantitative pump to proceed the reaction at 85° C. After finishing the dropping addition of aniline, the temperature is kept at 85° C. for aging for 2 hours, then the temperature is raised to 105° C. After water and part of the solvent are removed, a benzoxazine resin solution with 56 wt % solid is obtained. According to gel permeation chromatography (GPC) analysis, the proportion of the tri-functional resin monomer in this benzoxazine resin is up to 60 area percent (Area %) or more.

Provenance & Evidence