Process of incorporating foamable materials in corrugated paperboard and the article derived therefrom

Claim 1

THE PROCESS OF MAKING FOAM FILLED CORRUGATED PAPERBOARD WHICH IS COMPRISED OF TWO SPACED SUBSTANTIALLY PARALLEL OUTER SHEETS, A CORRUGATED INNER SHEET BETWEEN SAID OUTER SHEETS, WHICH COMPRISES FORMING AN ADHESIVE FOAMING MIXTURE COMPRISING 100 PARTS BY WEIGHT OF A CASTOR OIL BASED URETHANE POLYMER CONTAINING BY WEIGHT 85 PARTS OF CASTOR OIL, 15 PARTS OF POLYETHYLENE GLYCOL AND 100 PARTS OF TOLYLENE-DIISOCYANATE CONTAINING 80% 2,4-ISOMER AND 20% 2,6-ISOMER HAVING A VISCOSITY OF APPROXIMATELY 1 M POISES, HEATING THE URETHANE POLYMER TO 70*C. AND THEREAFTER COOLING THE SAME TO 25*-30*C. ADDING TO THE SAID URETHANE POLYMER 6.8 PARTS BY WEIGHT OF A BUFFER CATALYST COMPRISING BY WEIGHT 24 PARTS OF 35% HYDROCHLORIC ACID, 42 PARTS OF DIETHYL ETHANOLAMINE AND 34 PARTS OF WATER, THROUGHLY MIXING THE COMPONENTS FOR 30 TO 40 SECONDS UNTIL THE MIXTURE IS ABOUT THE CONSISTENCY OF WHIPPED CREAM, COATING THE MIXTGURE ON THE INNER FACE OF AT LEAST ONE LINER SHEET, APPLYING THE COATED INNER FACE OF THE SAID ONE LINER SHEET TO THE PEAKS OF CORRUGATIONS ON ONE FACE OF THE CORRUGATED SHEET WITH SAID COATING BEING ADHESIVELY SECURED TO THE PEAKS AND SPACING THE SAME FROM THE INNER FACE OF SAID ONE SHEET, PERMANENTLY ADHERING THE OTHER LINER SHEET TO THE OTHER FACE OF THE CORRUGATED SHEET, AND FOAMING THE SAID MIXTURE IN SITU WITH SUFFICIENT PRESSURE ON THE LINEARS TO ALSO FILL AT LEAST THE VOIDS BETWEEN ADJACENT FLUTES ON SAID ONE FACE OF THE CORRUGATED SHEET WITH THE FOAMED MIXTURE.