Method of making corrugated fibre board and products obtained thereby

Claim 1

TRIPLE WALL CORRUGATED PAPER BOARD WHICH IS FLAT AND ADAPTED FOR SCORING AND BENDING TO FORM A SHIPPING CONTAINER COMPRISING FOUR PAPER LINERS, THE OUTERMOST LINERS WEIGHING ABOUT 90 POUNDS PER 100 SQUARE FEET AND BEING FROM ABOUT .023 TO ABOUT .030 OF AN INCH THICK, TWO INTERMEDIATE LINERS WEIGHING ABOUT 42 POUNDS PER 100 SQUARE FEET AND BEING FROM ABOUT .013 TO ABOUT .016 OF AN INCH THICK, THREE CORRUGATED PAPER MEDIUMS, THE MEDIUMS BEING INTERPOSED BETWEEN THE LINERS IN EACH INSTANCE WITH HE CORRUGATIONS OF THE MEDIUM BEING PARALLEL TO EACH OTHER THROUGHOUT SAID BOARD, TWO OF SAID MEDIUMS BEING MADE WITH DEEP CORRUGATIONS OF THE A-TYPE HAVING A FLUTE DEPTH OF ABOUT 3/16 OF AN INCH WITH ABOUT 36 FLUTES PER LINEAL FOOT, AND A THIRD OF SAID MEDIUMS ON THE OUTSIDE OF THE CENTRAL ONE BEING MADE WITH LESS DEEP CORRUGATIONS OF THE C-TYPE HAVING A FLUTE DEPTH OF ABOUT 5/32 OF AN INCH WITH ABOUT 42 FLUTES PER LINEAL FOOT, THE WEIGHT AND CALIPER OF THE MEDIUMS BEING IN A RANGE FROM 30 POUNDS TO ABOUT 52 POUNDS PER 1000 SQUARE FEET AND FROM ABOUT .011 TO ABOUT .018 OF AN INCH, RESPECTIVELY, FIRST AND SECOND ADHESIVES APPLIED TO THE RIDGES OF THE MEDIUMS'' CORRUGATIONS FOR INTIMATELY AND RIGIDLY BONDING THE MEDIUMS AND LINERS TOGETHER, SAID FIRST ADHESIVE BONDING EACH OF THE CORRUGATED MEDIUMS AT ONE SIDE THEREOF TO A DIFFERENT ONE OF THE LINERS, TO FORM A SINGLE FACE CORRUGATED PAPER BOARD SHEET, SAID FIRST ADHESIVE HAVING A FIRST PREDETERMINED SETTING TEMPERATURE AND BEING ONE OF A SODIUM SILICATE MIX ADDED WITH ABOUT 12% CLAY AND A STARCH MIXTURE CONTAINING 40 POUNDS IN A 666 GALLON BATCH AND GIVING A CAUSTIC CONTENT OF ABOUT 3.3%, SAID SECOND ADHESIVE BEING APPLIED TO THE RIDGES AT THE OPPOSITE SIDE OF THE MEDIUM OF EACH OF SAID SINGLE FACE SHEETS AND HAVING A SECOND SETTING TEMPERATURE WHICH IS LOWER THAN SAID FIRST SETTING TEMPERATURE OF SAID FIRST ADHESIVE, SAID SECOND ADHESIVE BEING OF A SODIUM SILICATE FORMULA CONTAINING ABOUT 70% SODIUUM SILICATE, 6% STARCH, 18% CLAY, AND 6% BORAX ON A DRY WEIGHT BASIS AND A STARCH FORMULA MODIFIED TO CONTAIN ABOUT 20% OF A POLYVINYL ACETATE EMUULSION, THE LOWER SETTING TEMPERATURE OF SAID SECOND ADHESIVE ENABLING SAID SECOND ADHESIVE TO BE SET BY SAID ADDITIONAL HEATING AT A TEMPERATURE WHICH SAFEGUARDS SAID FIRST ADHESIVE FROM OVERHEATING.