Paper and paper coating products produced using multi-phase calcium silicate hydrates

Abstract

A paper composition including multiphasic calcium silicate hydrate fillers. 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 a reactor, and pressurized. The hydrothermal reaction is carried out while maintaining the initial dilution for a preselected reaction time at a preselected reaction temperature. The calcium silicate hydrates have high water absorption and light scattering power, and have optical and physical properties making them highly desirable as a filler in papermaking.

1 . A paper composition, said composition comprising: an effective amount of a filler, said filler comprising a multiple phase calcium silicate hydrate comprising foshagite and xonotlite, and having peaks in the XRD patterns from the foshagite and xenotlite components in the complex having the characteristic XDR shown in  FIG. 1 .  
     
     
         2 . A paper composition according to  claim 1 , wherein said multiple phase calcium silicate hydrate has a water absorption range of at least about 500 percent.  
     
     
         3 . A paper composition according to  claim 1 , wherein said multiple phase calcium silicate hydrate has a water adsorption range of up to approximately 1000 percent.  
     
     
         4 . A highly absorbent coating formulation mixture for coating on a printing paper substrate, said coating formulation mixture comprising: 
 an effective amount of a multiphasic calcium silicate hydrate, said multiphasic calcium silicate hydrate comprising foshagite and xonotlite having peaks in the XRD patterns from foshagite and xenotlite components with the characteristic XDR shown in  FIG. 1 .    an aqueous starch solution;    a dispersant; and    a binder.    
     
     
         5 . A slurry of multiphasic calcium silicate hydrate, said slurry comprising: 
 fibrous primary crystals interlocked in secondary particles of calcium silicate, said primary crystals and said secondary particles having peaks in XRD patterns from the foshagite and xenotlite components having the characteristic XDR shown in  FIG. 1 ; and    wherein said interlocked fibrous primary crystals and secondary particles are dispersed in water.    
     
     
         6 . A slurry of multiphasic calcium silicate crystals as defined in  claim 5  in which contains the water is present in an amount of 80 percent or more by weight in said slurry.  
     
     
         7 . A slurry of multiphasic calcium silicate crystals as defined in  claim 6  wherein at least about 95% of the secondary particles are less than 40 microns in outside diameter.  
     
     
         8 . A slurry of multiphasic calcium silicate crystals as defined in  claim 7  wherein at least about 80% of the secondary particles are 10 to 40 microns in outside diameter.