Producted And Modified Water-Borne Polyurethane In Wooden Furniture

With the strong demand for protecting environment, wate r-borne coatings of low VOC are being studied in the coatin gs industry. But water-borne polyurethane used to wooden fu rniture has some shortcomings of its film in hardness and w ater resistance. In order to improve the hardness and waterresistance, a number of experiments are done by studying o n prescription of water-borne polyurethane and content of i ts composition.Firstly, we should prepare polyester glycol in order toprepare water-borne polyurethane emulsion used to wooden f urniture. Polyester giycols having designed molecular weigh t of 1000 are synthesized by ethylene glycol and mixture ofphthalic anhydride and adipic acid (morl radio =40:60)on condition that molar excess content of glycol is 15%, and h igh vacuum time is 8h.The produced polyester glycols havingthe same molecular weight as designed measure up to standard of material. And Water-borne polyurethane emulsion' s hardness is better than others are produced by aliphatic po lyester glycol.Through the experiment, we find the effects of major fa ctors such as content of DMBA, content of chain extender an d NCO/OH ratio, and confirm their content: Content of DMBA is about 7%, content of chain extender is about 15%, and NC 0,/OH ratio is 1.2:1. But it is no obvious improvement in wa ter resistance of water -borne polyurethane. So polyacrylat e modified water-borne polyurethane is studied in this pape r in order to improve the water resistance of water-borne p olyurethane.We consider that the mixture is the best synthetic meth od in the three methods. Polyacrylate modified water-borne poly -urethane emulsion with qualified hardness and improve d water resistance can be prepared by studying its influenc e factors on condition that PA/PU mass ratio is 60:40. Beca use Polyacrylate emulsion ' s vitrification point is higher than room- temperature, we must add film assistant in to re action in order to reduce vitrification point of polyacryia te modified water-borne polyurethane.In conclusion, water-borne polyurethane is produced by...