| Due to the shortage of wood resources,low effective utilization rate and high cost in the industry of solid wood furniture,wood-based panel have gradually become the mainstream product.With the development of science and technology and the improvement of the quality of life,people’s requirements for the quality of wood-based panels are getting higher and higher.Among them,melamine-formaldehyde（MF）resin impregnated adhesive film paper veneer board with MF resin colorless transparent,high bonding strength of the most rapid development.However,it still has disadvantages such as poor hydrophobic performance,high brittleness,poor storage stability and high free formaldehyde content,which limit its development to a certain extent.Therefore,improving MF resin performance is of great value in the practical application of impregnated adhesive film paper veneer board.The main research contents and achievements are as follows:（1）Polyvinyl alcohol grafted with sodium methyl silicate（SMS-PVA）was synthesized to modify MF resin.Firstly,the synthesis process of pure MF resin was determined as formaldehyde/melamine molar ratio of 2.5,p H=8～9,T=80℃.Under this condition,the solid content of pure MF resin was 54.44%,the viscosity was 15.70",the free formaldehyde was0.77%,and the storage life was 7d.The comprehensive performance was good and the cost was economical.Secondly,the optimum synthesis condition of SMS-PVA is that 15%PVA solution reacts with 10%SMS solution at 80℃for 2h to prepare clear and transparent SMS-PVA modifier.Under this condition,the modifier has good water resistance and storage stability,moderate viscosity,and is easy to use and transport.Finally,the modification agent was added in the basic synthesis stage of MF resin,and the modification agent and MF resin were characterized and analyzed by FT-IR,XRD,1H-NMR,DSC,SEM and EDS.The results showed that Si-O-C bond was formed in sm S-PVA and MF resin modified by SMS-PVA,that is,SMS was successfully grafted by PVA and MF resin was modified.（2）PMM resin was introduced to improve the compatibility of SMS and MF resin,and SMS-PVA-PMM modifier was synthesized to modify MF resin.Firstly,PMM resin was synthesized under the conditions of formaldehyde/melamine/methanol mole ratio of 2.5:1:6,p H=5～5.5,T=50℃.The content of free formaldehyde,solid content and etherification degree of PMM resin were moderate.Then,the synthesis conditions of SMS-PVA-PMM modifier were determined as PVA:SMS:PMM=15%:20%:3%,and the reaction time was 2h at 70℃.Under these conditions,the modified agent was clear and transparent,with excellent viscosity and storage stability.Finally,the modifier and MF resin before and after modification were characterized and analyzed by FT-IR,XRD,1H-NMR,DSC,SEM and EDS.The results showed that SMS-PVA-PMM and MF resin modified by SMS-PVA-PMM contained ether bond C-O-C.The existence of vibration absorption peaks of-CH2and-CH3hydrogen atoms in N-CH2-O-CH3indicates that the modifier SMS-PVA-PMM has been successfully crosslinked and modified MF resin.（3）MF resin modified by SMS-PVA and SMS-PVA-PMM was practically applied to impregnated paper decorative panels.Firstly,the impregnation drying and hot pressing laminating process of modified MF resin in the actual application in the factory was determined.Secondly,the toughness of impregnated paper made with SMS-PVA and SMS-PVA-PMM modified MF resin was studied.Finally,the surface hydrophobicity,stability,gloss,abrasion resistance and scratch resistance of impregnated paper pressed into decorative panel were tested.The results show that the two modifiers can improve the flexibility of MF resin impregnated paper,improve the hydrophobicity,wear resistance and scratch resistance of the decorative panel,and reduce the gloss. |
PDF Full Text Request