| 摘要 |
A polymer composition that can be used to cure a novolac resin at a lower temperature than conventional novolac curing agents and with reduced emission of volatile compounds is disclosed. The novolac curing agent polymer composition is prepared by mixing and reacting in aqueous solution a phenolic monomer and an aldehyde in the presence of a basic catalyst to forum an intermediate resin, and reacting the intermediate resin with an amine to form the polymer composition. The aldehyde to phenolic monomer molar ratio in the reaction should be at least about 1.0:1, and preferably is at least about 2.0:1. The preferred amine is hexamethylenetetramine, and it is preferred that the hexamethylenetetramine to phenolic monomer molar ratio is at least about 0.12:1. In a preferred version, the aldehyde is formaldehyde, and the phenolic monomer is selected from the group consisting of phenol, substituted phenols, and mixtures thereof, with phenol itself being the most preferred phenolic monomer. The polymer is particularly advantageous in that the reaction temperature is lowered compared to other conventional curing agents, the unreacted phenolic monomer in the polymer composition may be adjusted to levels less than about 0.5 weight percent, and the unreacted aldehyde in the polymer composition may be adjusted to levels less than about 0.1 weight percent. As a result, the polymer releases minimal volatile compounds when used to cure novolac resins, and unlike conventional resole curing agents, has an indefinite shelf life in both the pure form and when blended with a novolac resins. |
