Research Of Low-formaldehyde Melamine Resin As Wet Strengthening Agents

With the rapid progress of science and technology and the continuous improvement of living standards,people have a higher requirement about the quality of their living conditions.Using different impregnated paper and veneers plate,can produce realistic texture and soft smooth pockmarked face,the laminate floor generally recognized and widely used by the furniture industry and interior decoration industry, one of which is the laminate floor covering decorated with melamine-formaldehyde resin impregnated paper,which has developed fastest and become the main product of Chinese wooding floor market.But it has many shortcomings,such as poor flexibility,low solid content and poor storage stability,especially the high content of free formaldehyde limit its development.Therefore,the study of low formaldehyde resins,while improving the performance of resin,has important economic value and environmental significance.By the determination of the appearance,reaction time,solid content,free formaldehyde content,storage stability and mechanical properties of impregnated paper of MF resins,We explore the better synthesis process of melamine-formaldehyde wet strength agent and use modern instrumental to analysis the products.The main results are shown as follows:(l)The better reaction conditions of solution polymerization are described as below: n(formaldehyde):n(melarnine)=2.5:1,n(ethylene glycol):n(melamine)=2.0:1,triethanolamine as the catalyst,pH=8-9,the reaction temperature is 80～90℃, melamine using three feeding method (50%-40%-10%),the Water dilution of reaction end point should be controlled in 2～3.(2)Compared with the single formaldehyde absorber,caprolactam collaboration with H2O2 as formaldehyde absorbent,can reduce the free formaldehyde content of MF resins more effectively,while increasing the storage stability and impregnated paper mechanical properties.(3)FTIR indicates the exist of the ethylene glycol monomer in the MF resins.Ethylene glycol toughened MF resin is successfully prepared. By the FTIR study of cured and uncured MF resins,proved that the melamine resin curing by methylene or dimethylene cross-linked with each other in the form of ether bond.(4)DSC study shows the addition of ethylene glycol makes the curing temperature of MF resins rise, but MF resin modified with caprolactam and H2O2 has a lower curing temperature.Successfully avoided the degradation and decreased in performance of MF resins because of high temperature.