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 the urea-formaldehyde resin after adhesive mixing is reduced for 10-30%. Additionally, the composite foaming agent of the invention has the advantages of excellent safety, no adverse effect in the using process and capability for effectively reducing the release amount of the formaldehyde of the artificial board. Furthermore the mechanical properties of the prepared artificial board can equally obtain the requirement of the national standard.