A METHOD FOR INCREASING OPACITY OF PAPER AND PAPER PRODUCED BY SUCH METHOD

摘要

A method for the hydrothermal preparation of calcium silicate hydrates. Multi-phase calcium silicate hydrates, having unique physical and chemical properties, are prepared by hydrothermal reaction of specified ratios of CaO and SiO2, normally starting from slurries of slaked lime and from fluxed calcined diatomaceous earth, each of which is at about the atmospheric boiling point before being mixed and charged to the reactor, and pressurized. The hydrothermal reaction is carried out while maintaining the initial dilution for a pre-selected reaction time at a pre-selected reaction temperature. The calcium silicate hydrates produced have high water absorption and light scattering power, and have optical and physical properties making them highly desirable as a filler substitute in papermaking.