Composite foaming agent for urea-formaldehyde resin, preparing method and application thereof

The present invention discloses a composite foaming agent for urea-formaldehyde resin, a preparing method and an application thereof. The composite foaming agent of the invention is composed of a foaming agent, a foam stabilizer and a dispersing agent. After the composite foaming agent is added into the urea-formaldehyde resin additive, the volume of the urea-formaldehyde resin can be increased for 2-3 times for forming the fine, uniform and long-lasting foamed urea-formaldehyde resin, effectively regulating the surface tension of the glue solution, reducing the conglobation phenomenon of flour, increasing the fluidity of the urea-formaldehyde resin, settling the adverse phenomena of glue bleeding, glue leakage, non-homogeneous adhesive layer, etc. which commonly exist in the prior urea-formaldehyde resin adhesive, so that the urea-formaldehyde resin on the plate blank of the veneer board has excellent homogeneity and the bleeding balancing is kept and the total usage of flour and theurea-formaldehyde resin a