Method and apparatus for preparing thin films of high melting point thermoplastics and the application thereof to paper and the like

Claim 1

THE METHOD OF COATING A WEB OF MATERIAL SUCH AS PAPER OR THE LIKE WITH A HIGHLY VISCOUS COATING COMPOSITION HAVING A VISCOSITY AT 190* C. AT LEAST OF THE ORDER OF THE VISCOSITY OF POLYETHYLENE HAVING A MOLECULAR WEIGHT OF THE ORDER OF 19,000 AND HAVING A MINIMUM WORKING TEMPERATURE IN EXCESS OF 240* F., WHICH COMPRISES DRYING THE WEB TO REDUCE THE MOISTURE CONTENT THEREOF SUBSTANTIALLY TO ZERO, BRINING THE WEB OF MATERIAL INTO CONTACT WITH A ROATING HEATED ROLL, CARRYING THE WEB ON SAID ROLL TO THE NIP FORMED BETWEEN SAID ROTATING ROOL A SUBSTANTIALLY STATIONARY PARELLEL ROLL, FEEDING A SUFFICIENT AMOUNT OF THE COATING COMPOSITION HEATED TO AT LEAST ITS MINIMUN WORKING TEMPERATURE BETWEEN SAID ROTATING ROLL AND THE SUBSTANTIALLY STATIONARY ROLL TO FORM A ROTATING ROLL-LIKE MASS OF SAID COATING COMPOSITION THEREBETWEEN EXTENDING SUBSTANTIALLY THE LENGTH OF THE NIP AND CONTINUOUSLY SUPPLY THE COATING COMPOSITION HEATED TO AT LEAST ITS MINIMUM WIRKING TEMPERATURE INTO THE ROATING ROOL-LIKE MASS WITHOUT PRECONTACTING ANY PORTION OF THE WEB THEREWITH TP PROVIDE A SUPPLY OF THE COATING COMPOSITION SUBSTANTIALLY UNITFORMYL BETWEEN THE ROLLS WHEREBY CONTACT BETWEEN THE ROTATING ROLL-LIKE MASS AND THE WEB IS LIMITED TO PREVENT CHARRING OF THE WEB, PRESSURE THE TWO ROLLS TOGETHER, AND CORRELATING THE TEMPERATURE OF THE COATING COMPOSITION, THE ROLLS AND THE WEB WITH THE PRESSURE SO AS TO PASS THROUGH THE NIP, THE WEB AND A COATING OF PREDETERMINED THICKNESS OF THE COATING COMPOSITION ON THE SURFACE THEREOF.

Claim 2

THE METHOD OF COATING A WEB OF MATERIAL SUCH AS PAPER OR THE LIKE WITH A HIGHLY VISCOUS COATING COMPOSITION HAVING A VISCOSITY AT 190* C. AT LEAST OF THE ORDER OF THE VISCOSITY OF POLYETHYLENE HAVING A MOLECULAR WEIGHT OF THE ORDER OF 19,000 AND HAVING A MINIMUM WORKING TEMPERATURE IN EXCESS OF 240* F., WHICH COMPRISES DRYING THE WEB TO REDUCE THE MOISTURE CONTENT THEREOF SUBSTANTIALLY TO ZERO, BRINING THE WEB OF MATERIAL INTO CONTACT WITH A ROATING HEATED ROLL, CARRYING THE WEB ON SAID ROLL TO THE NIP FORMED BETWEEN SAID ROTATING ROOL A SUBSTANTIALLY STATIONARY PARELLEL ROLL, FEEDING A SUFFICIENT AMOUNT OF THE COATING COMPOSITION HEATED TO AT LEAST ITS MINIMUN WORKING TEMPERATURE BETWEEN SAID ROTATING ROLL AND THE SUBSTANTIALLY STATIONARY ROLL TO FORM A ROTATING ROLL-LIKE MASS OF SAID COATING COMPOSITION THEREBETWEEN EXTENDING SUBSTANTIALLY THE LENGTH OF THE NIP AND CONTINUOUSLY SUPPLY THE COATING COMPOSITION HEATED TO AT LEAST ITS MINIMUM WIRKING TEMPERATURE INTO THE ROATING ROOL-LIKE MASS WITHOUT PRECONTACTING ANY PORTION OF THE WEB THEREWITH TP PROVIDE A SUPPLY OF THE COATING COMPOSITION SUBSTANTIALLY UNITFORMYL BETWEEN THE ROLLS WHEREBY CONTACT BETWEEN THE ROTATING ROLL-LIKE MASS AND THE WEB IS LIMITED TO PREVENT CHARRING OF THE WEB, PRESSURE THE TWO ROLLS TOGETHER, AND CORRELATING THE TEMPERATURE OF THE COATING COMPOSITION, THE ROLLS AND THE WEB WITH THE PRESSURE SO AS TO PASS THROUGH THE NIP, THE WEB AND A COATING OF PREDETERMINED THICKNESS OF THE COATING COMPOSITION ON THE SURFACE THEREOF.