Gas Content

A tissue sheet with variable formation and moisture interacts unevenly with the Yankee dryer and creping blade. The result is a variable crepe structure, local softness differences, reduced bulk uniformity, and irregular surface appearance. The crepe process amplifies pre-existing sheet non-uniformities rather than correcting them.

Gas can produce bubbles in the forming zone, causing thin areas, pinholes, and weak spots. Tissue grades are particularly sensitive to these effects because their low basis weight provides little opportunity to mask sheet non-uniformities. Holes and weak spots originating at the headbox may be amplified by creping, leading to problems such as sheet breaks and quality rejects.