Polyvinyl alcohol fibers and process of treating

Claim 1

A METHOD OF IMPROVING ORIENTED FILAMENTS OF LINEAR SYNTHETIC POLYMERS IN WHICH FROM 45 TO 50% OF THE CARBON ATOMS OF THE LINEAR POLYMER CHAIN ARE ATTACHED TO HYDROXYL GROUPS WHICH POLYMERS CONSIST TO THE EXTENT OF AT LEAST 90%, BY WEIGHT, OF VINYL ALCOHOL, -CH2CHOH-, UNITS, ANY REMAINDER BEING POLYMERIZABLE VINYLIDENE COMPOUND UNITS, WHICH COMPRISES HEATING THE ORIENTED FILAMENTS UNDER TENSION CONTROLLED TO PREVENT MORE THAN 60% SHRINKAGE REFERRED TO THE INITIAL DRAWN LENGTH OF THE FIBER AT A TEMPERATURE WITHIN THE RANGE OF 190-255*C. AND WITHIN THE RANGE FROM 1*C. BELOW TO 30*C. BELOW THE SOFTENING POINT OF THE FILAMENTS FOR A TIME BETWEEN ABOUT ONE SECOND AND ABOUT FORTY MINUTES UNTIL THE FILAMENTS SHRINK NOT MORE THAN 10% WHEN IMMERSED IN WATER AT 60*C. AND DRIED, THE HEATING AT 190-255*C. BEING DISCONTINUED BEFORE THE FILAMENTS BECOME DISCOLORED; SWELLING THE FILAMENTS BY IMMERSION IN AN INERT AQUEOUS MEDIUM CONTAINING 50-100% WATER AT A TEMPERATURE OF AT LEAST 60*C. BUT NOT HIGHER THAN 1*C. BELOW THE TEMPERATURE AT WHICH THE FILAMENTS STICK TOGETHER FOR A TIME BETWEEN ABOUT THREE SECONDS AND BOUT FIFTEEN MINUTES UNTIL THE FILAMENTS ARE SATURATED BUT DISCONTINUING THE IMMERSION BEFORE THE FILAMENTS HAVE LOST 20% OF THEIR INITIAL DRY TENSILE STRENGTH; DRYING THE FILAMENTS IN THEIR SWOLLEN CONDITION; AND TREATING THE SUBSTANTIALLY WATER-FREE, SWOLLEN, HEAT-SET, ORIENTED FILAMENTS IN AN INERT, SUBSTANTIALLY ANHYDROUS MEDIUM WITH A MONOALDEHYDE OF UP TO TWENTY CARBONS HAVING THE ALDEHYDE, -CHO, GROUP ATTACHED TO ANNULAR CARBON OF A CYCLIC NUCLEUS OF AT LEAST FIVE ANNULAR ATOMS AT A TEMPERATURE OF AT LEAST 50*C. BUT BELOW THE DECOMPOSITION POINT OF THE REACTANTS UNTIL, AS INDICATED BY GAIN IN WEIGHT, 25-75% OF THE HYDROXYL GROUPS IN THE FILAMENT HAVE REACTED WITH THE ALDEHYDE.

Claim 2

A METHOD OF IMPROVING ORIENTED FILAMENTS OF LINEAR SYNTHETIC POLYMERS IN WHICH FROM 45 TO 50% OF THE CARBON ATOMS OF THE LINEAR POLYMER CHAIN ARE ATTACHED TO HYDROXYL GROUPS WHICH POLYMERS CONSIST TO THE EXTENT OF AT LEAST 90%, BY WEIGHT, OF VINYL ALCOHOL, -CH2CHOH-, UNITS, ANY REMAINDER BEING POLYMERIZABLE VINYLIDENE COMPOUND UNITS, WHICH COMPRISES HEATING THE ORIENTED FILAMENTS UNDER TENSION CONTROLLED TO PREVENT MORE THAN 60% SHRINKAGE REFERRED TO THE INITIAL DRAWN LENGTH OF THE FIBER AT A TEMPERATURE WITHIN THE RANGE OF 190-255*C. AND WITHIN THE RANGE FROM 1*C. BELOW TO 30*C. BELOW THE SOFTENING POINT OF THE FILAMENTS FOR A TIME BETWEEN ABOUT ONE SECOND AND ABOUT FORTY MINUTES UNTIL THE FILAMENTS SHRINK NOT MORE THAN 10% WHEN IMMERSED IN WATER AT 60*C. AND DRIED, THE HEATING AT 190-255*C. BEING DISCONTINUED BEFORE THE FILAMENTS BECOME DISCOLORED; SWELLING THE FILAMENTS BY IMMERSION IN AN INERT AQUEOUS MEDIUM CONTAINING 50-100% WATER AT A TEMPERATURE OF AT LEAST 60*C. BUT NOT HIGHER THAN 1*C. BELOW THE TEMPERATURE AT WHICH THE FILAMENTS STICK TOGETHER FOR A TIME BETWEEN ABOUT THREE SECONDS AND BOUT FIFTEEN MINUTES UNTIL THE FILAMENTS ARE SATURATED BUT DISCONTINUING THE IMMERSION BEFORE THE FILAMENTS HAVE LOST 20% OF THEIR INITIAL DRY TENSILE STRENGTH; DRYING THE FILAMENTS IN THEIR SWOLLEN CONDITION; AND TREATING THE SUBSTANTIALLY WATER-FREE, SWOLLEN, HEAT-SET, ORIENTED FILAMENTS IN AN INERT, SUBSTANTIALLY ANHYDROUS MEDIUM WITH A MONOALDEHYDE OF UP TO TWENTY CARBONS HAVING THE ALDEHYDE, -CHO, GROUP ATTACHED TO ANNULAR CARBON OF A CYCLIC NUCLEUS OF AT LEAST FIVE ANNULAR ATOMS AT A TEMPERATURE OF AT LEAST 50*C. BUT BELOW THE DECOMPOSITION POINT OF THE REACTANTS UNTIL, AS INDICATED BY GAIN IN WEIGHT, 25-75% OF THE HYDROXYL GROUPS IN THE FILAMENT HAVE REACTED WITH THE ALDEHYDE.