In the manufacture of soft tissues and related paper products such as facial tissue, bath tissue, kitchen towels and dinner napkins, aqueous suspensions of papermaking fibers are deposited onto a forming fabric to form an embryonic web. The embryonic web is dewatered, dried and thereafter creped to soften the resulting sheet. In carrying out the creping step, a creping adhesive is typically sprayed onto the surface of a rotating creping cylinder, such as a Yankee dryer, to help build an adhesive (dryer) coating to which the tissue sheet is adhered. The adhered tissue is dislodged from the surface of the creping cylinder by contact with a doctor blade. Crepe quality is maintained by regularly changing the doctor blades in order to maintain a uniform dryer coating, which becomes uneven due to skulch formation on the dryer surface. A non-uniform dryer coating is one of the major reasons for very frequent doctor blade changes. Blade life may be as short as 30 minutes in some instances. Necessary and frequent blade changes contribute to waste and delay and are also an expense to be minimized.
Hence there is a need for improved creping methods which are more economical and provide more consistent quality.
USPTO Backgrounds
USPTO Backgrounds