| 摘要 |
<p>Paper sizing compsn. contains:- (I) aqs. fortified rosin size having K+ as is not 50, pref. is not 75 mole% of metal cations, acid value is not 5, solids content 62.5 - 72.5 wt.% on compsn.; and (II) 13.5-18 wt.% on solids of a water-miscible monohydric alcohol. It is prepared by mixing rosin with 0.25 - 12% of its wt of an alpha, beta-unsatd. acid, anhydride, half ester (or mixt.); saponifying and diluting to the given acid value and solid content; and adding (II). Tall oil rosin is preferred, and it is pref, first treated with 4.5-8% of formaldehyde using 0.05-1% of an acid catalyst, esp. an organosulphonic acid, which is afterwards neutralised Sufficient rosin is then added to give a blend with formaldehyde content of 2-4 wt.%, which is heated at 240-290 deg.C for 1/2 - 3 hrs.</p> |
