Study On Coating Adhesion Improvment Of Heat-treated Wood

Effective finishing can beautify wood products,as well as increase their performance and quality and prolong their life.High temperature heat treatment,which can improve the moisture resistance and dimensional stability of wood products,has been a new development direction in wood processing industry.But it is harmful to the film adhesion of wood coating,because the surface wettability of heat-treated wood is low.The purpose of this paper is to improve the coatings film adhesion of heated-wood.The research is carried out from three aspects.1)Three chemicals was chosen to modify the wood surface to study the influence of each chemical and quantities on surface wettability and wood paint film adhesion.the morphology of UV coating section SEM was investigated as well.2)In order to determine a better coating structure,elastic coating and UV coating were used to research the influence of coating composition on adhesion of paint film,flexibility,hardness,etc.3)Nano-microcrystalline Cellulose(MCC)was used to study physical and chemical action between modified MCC and Heat treated wood surface,the influence of coupling agent modified MCC on reinforcing styrene acrylic wood coating adhesion was discussed.The main results and conclusions were summarized as follows:(1)The heat-treated wood's surface wettability decreased,the UV coating on the surface of the wood has lower permeability and bad film adhesion.(2)Fluorocarbon surfactant(FC4430),vinyltriacetoxysilane(VAS),and silane coupling agent(KH550)were used to modify the heat-treated wood and natural wood surface.It turned out that KH550 or VAS can improve the surface wettability of wood and the permeability of coating,for was the opposite.KH550 treatment can improve the adhesion force of UV curing coating on heat-treated wood,Adhesion grade from grade 2 to grade 1;No significant improvement was observed after FC4430 or VAS treatment.(3)The fracture surface SEM micrograph of UV curing coating showed: after KH550 treatment,a more uniform surface film was formed on heat-treated wood surface and more compact film inside,the combination of the paint film with wood more closely.(4)Under the same coating weight and curing condition,the composition and structure of the coating had some degree impact on the adhesion,hardness,wearing resistance.The floor paint composed by three UV high-elastic undercoat and two UV wear-resisting finishing coat had excellent performance with 3H hardness,wearing resistance is 0.086g/100 r,grade 1 adhesion,6.88% maximum elongation at break.The complex coating composed by UV high-elastic undercoat and UV wear-resisting finishing.coat can effectively solve the problem of floor and UV coating micro crack.(5)MCC with KH550 modification to add the wood styrene acrylic polymerization emulsion had different impact on the property of coating.The film adhesion,tensile strength and wear resistance of modified styrene acrylic waterborne wood lacquer was increased,film breaking elongation and flexibility is reduced,smaller film hardness change.The addition of modified MCC lead to styrene acrylic polymerization emulsion's wettability can fell slightly,but the film adhesion on heat-treated wood has certain improvement,Compound to add MCC after the completion of the emulsion preparation,on the film performance,especially has the greatest effect in the film adhesion,2 levels higher than that of before modification.