| 摘要 |
PURPOSE:To provide the titled agglomerate giving improved whiteness of paper and opacity of print, by adding urea to a precondensate of urea and formaldehyde, mixing the mixture with an acidic aqueous solution, and curing the product, wherein the mixing of the aqueous solution to the mixture is carried out at a specific molar ratio. CONSTITUTION:Condensed urea (U1) is made to react with formaldehyde (F) and other additive to obtain a precondensate. Additional urea (U2) is added to the precondensate to obtain a homogeneously mixed solution, which is mixed with an acidic aqueous solution (e.g. sulfuric acid) and cured usually at room temperature - about 100 deg.C within 50sec. The molar ratio of U1+U2:F is 1:1-1:2, and U2/(U1+U2) is 0.10-0.70. USE:Filler for reducing the weight of newsprint paper roll, printing paper, etc. |
