Fire resistant materials

In a method forming a laminated corrugated cellulose product comprising at least two sheets of cellulose material including at least one liner board and at least one fluted medium sheet, the improvement wherein an aqueous solution of sodium silicate adhesive material is applied to at least one of said sheets in an amount of at least three pounds per thousand square feet of laminated product, and the sheets are placed in pressing relationship under conditions to promote curing of said adhesive, the sodium silicate being dried-in-place, substantially under ambient drying conditions, whereby bound water molecules contained in the sodium silicate are retained.

A method of improving the fire resistance of a laminated corrugated cellulose product comprising at least two sheets of cellulose material including at least one liner board and at least one fluted medium sheet affixed to one another by a sodium silicate adhesive applied as an aqueous solution, the improvement wherein said sodium silicate is dried-in-place, substantially under ambient drying conditions, whereby bound water molecules contained in the sodium silicate are retained, said dried-in-place sodium silicate being present in an amount (dry weight) of at least about three pounds per thousand square feet of laminated product, said dried-in-place sodium silicate being heat-foamable to produce a mechanically stable further element capable of resisting the passage of fire therethrough in the event said product is exposed to fire or heat.

A new use of sodium silicate as a combination laminating adhesive and fire resistant barrier for laminated corrugated cellulose products, said sodium silicate being applied to said products from an aqueous solution and dried-in-place, substantially under ambient drying conditions, whereby bound water molecules contained in the sodium silicate are retained, whereby to provide an element present in an amount (dry weight) of at least about three pounds per thousand square feet of laminated product and which is heat-foamable to produce a barrier capable of resisting the passage of heat or fire therethrough in the event said product is exposed to fire or heat.

In a method for manufacturing a laminated corrugated cellulose product comprising at least two sheets, wherein said at least one of said sheets comprises a cellulose liner board and at least one other of said sheets comprises a fluted cellulose medium sheet, the improvement wherein said sheets are adhesively fixed to one another by means of a sodium silicate applied from aqueous solution in an amount of at least three pounds per thousand square feet of laminated product and dried-in-place while said sheets are maintained in pressing relationship, the step of drying said sodium silicate in-place occurring substantially under ambient drying conditions, whereby bound water molecules contained in the sodium silicate are retained.