| 摘要 |
A wet-laid composite, soft, bulky and absorbent paper structure is prepared from two or more layers of furnish which are preferably comprised of different fiber types. The layers are preferably formed from the deposition of separate streams of dilute fiber slurries, the fibers typically being relatively long softwood and relatively short hardwood fibers as used in tissue papermaking, upon one or more endless foraminous screens. The layers are subsequently combined to form a unitary web, and the layered, unitary web is dewatered by the application of fluid forces. The moist, layered web is thereafter transferred to an open mesh drying/imprinting fabric. The application of a fluid force to the web creates patterned discrete areas of fibers numbering from about 100 to about 3600 per square inch of projected surface area on the side of the web which contacts the drying/imprinting fabric. The undensified discrete areas which correspond to the mesh openings in the drying/imprinting fabric extend outwardly from the fabric side of the layered web and generally assume the form of totally-enclosed pillows, conically grouped arrays of fibers, combinations thereof or the like. Following transfer of the moist, layered paper web to the drying/imprinting fabric, the web is thermally predried to a fiber consistency of at least about 30 percent. The thermally predried, layered paper web may then be compacted in discrete areas corresponding to the knuckles of the drying/imprinting fabric to impart strength and to adhere the web to the surface of a dryer drum for final drying and/or creping. In the alternative, the thermally predried, layered paper web may be finally dried directly on the drying/imprinting fabric without any compaction by the fabric knuckles. In the latter event, the finally dried web is preferably subjected to mechaical micro-creping to impart softness, flexibility and drape to the fnished sheet. The above described layered structures exhibit significantly improved bulk, flexibility, compressibility, drape and absorptive capacity when compared to prior art paper sheets formed by similar processing techniques from a single slurry comprised of a homogeneous mixture of similar fibers. In addition, the structures which are stratified with respect to fiber type typically yield finished paper sheets having significantly improved tactile impression and softness. |
