| Summary: | 碩士 === 南臺科技大學 === 化學工程與材枓工程系 === 107 === A series of water soluble phenolic resin (WPF) for printing inks were synthesized with different molar ratios (0.25, 0.5, 0.75, 1, 1.25, 1.5) of formaldehyde to phenol (F/P) with calcium phenol, polyaldehyde, calcium oxide and hexamethylenetetramine (HMTA) as additives. The viscosity and surface tension of WPF was WPF-1 = 43.6 mN/m、WPF-2 = 46.5 mN/m and WPF-3 = 48.6 mN/m, respectively. The effects of F/P molar ratios on the physical properties of WPF were investigated by thermogravimetric, DSC and Rheological analysis, respectively. Form the TGA curves, the weight ratio of WPF were up to 85wt.%. Rheological behavior of the WPF reveals the viscosity of WPF was increased to 74 Pa·s at 60 °C in 3 hour, which illustrated that WPF can start to take place crosslinking reaction at 60 °C. On the other hands, amount of the free aldehyde within WPF was removed from 5,000 ppm to 0.1 ppm by reduction reaction using hydroxylammonium chloride. Finally, the compression strength of sand molds, which was manufactured by using the blend of casting sand with 3 wt.% of WPF and HMTA crosslinkers, were ca. 150~300 N/m2 after 3 points bending test.
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