Лако-красочные материалы — производство

The number of patents on lignin as a substitute or extender for phenolic wood adhesives during the past four decades is high [2]. Under certain conditions, up to 40% of PF adhesive can be replaced by lignosulfonate or black liquor without significantly extending the curing time or worsening board properties. Lignin-PF formulations have been used in manufacturing particleboard, fiberboard, and plywood. The reason for their application has to be seen in the lowering of costs, resulting from the difference in cost between PF and lignin. However, in most cases the lignin has to be pretreated by deionization, ultrafiltra­tion, or cation change. Two recent procedures that have become better known are dis­cussed next in more detail.