Process for resin impregnating cellulosic fabrics

Claim 1

THE PROCESS OF FINISHING FABRICS OF CELLULOSE AND REGENERATED CELLULOSE AND MIXTURES THEREOF WHICH COMPRISES INPREGNATING THE FABRIC WITH AN AQUEOUS SOLUTION OF WATER-SOLUBLE ACID-CATALYZABLE THERMOSETTING TEXTILE RESINS OF THE ALDEHYDE TYPE IN CONCENTRATION OF FROM SUBSTANTIALLY 5% TO SUBSTANTIALLY 20% BY WEIGHT OF THE SOLUTION CARBAZIDE HYDROCHLORIDE AS A CATALYST, IN MINOR PART BY WEIGHT, WITH A SOLUTION PICK-UP OF FROM SUBSTANTIALLY 70% TO SUBSTANTIALLY 90 % BY WEIGHT OF THE FABRIC IN THE DRY STATE, DRYING THE FABRIC AT TEMPERATURES BETWEEN ABOUT 200 F. AND ABOUT 350* F. UNTIL IT IS SUBSTANTIALLY DEVOID OF FREE MOISTURE, THE DRYING BEING AT A TEMPERATURE AND FOR A TIME SUCH THAT THE PH OF THE DRIED FABRIC IS NOT BELOW 6 PH AS DETERMINED BY INDICATOR SOLUTIONS, PROMPTLY AFTER SUCH DRYING, COOLING THE FABRIC SO SUBSTANTIALLY ROOM TEMPERATURE, PASSING THE DRIED, COOLED FABRIC THROUGH A PRESSURE MECHANICAL FINISHING CALENDER HEATED TO A TEMPERATURE SUCH THAT THE FABRIC IS HEATED TO A TEMPERATURE OF BETWEEN FROM SUSTANIALLY 100* F. TO SUBSTANTIALLY 200* F. IN ITS PASSAGE THERETHROUGHT, AND PASSING THE FABRIC THROUGH AN ATMOSPHERE HEATED TO FROM SUBSTANTIALLY 250* F. TO SUBSTANITALLY 350* F. FOR A RESIDENCY TIME FROM SUBSTANTIALLY 8 MINUTES AT THE LOWER TEMPERATURE TO SUBSTANTIALLY 2 MINUTES AT THE HIGHER TEMPERATURE.