Disposable paper towels are commonly manufactured and widely used. A primary function of these towels is absorbing liquid. Paper towels posses varying degrees of certain qualities which make them suitable for different tasks. Some of these qualities are softness, absorbent capacity, absorbent rate, and strength. The absorbent capacity is the maximum amount of liquid a paper towel can absorb, and the absorbent rate is the speed with which the paper towel can absorb liquid. The strength of a paper towel is generally the tensile strength of the paper towel which is a measure of the stress required to pull the paper towel apart.
Hand or wiper towels are a particular type of paper towel and are often used in washrooms for drying hands and for cleaning up liquid spills. These towels are also used for wiping surfaces clean with a solvent such as in washing windows or counter tops. Accordingly, towels must absorb relatively large quantities of liquid very quickly and possess enough strength so that they do not break apart when subjected to stress even when the towels are saturated with liquid. Further, it is also desirable for hand or wiper towels to be soft, particularly when the towels are used for drying hands so that they are comfortable to the user's skin and when wiping finished surfaces, such as desk tops or automobile exteriors, so that the towels do not scratch the finished surfaces.
Prior art hand or wiper towels which are made from cellulosic fibers are normally strong even when saturated with liquid, but often lack desirable levels of absorbent capacity, absorbent rate, and softness. These prior art towels are generally made with a conventional wet forming process wherein the beginning furnish contains chemical bonding agents to bind the cellulosic fibers together and promote the strength of the towel. The furnish is deposited on a traveling foraminous belt thereby forming a web of moist cellulosic fibers on top of the foraminous belt. The moist fibrous web is transferred to an absorbent carrier belt and then pressed by one or a series of rollers to remove water from the fibrous web and to compact the fibers in the web to further promote the strength of the towel. The pressed fibrous web is transferred to the outer surface of a rotating steam-heated dryer whereby part of the remaining water is evaporated from the fibrous web. The fibrous web is then "creped" by a blade positioned adjacent the outer surface of the dryer which scrapes the partially-dried fibrous web from the outer surface of the dryer. The creped fibrous web is then conveyed over a series of steam-heated dryers to evaporate the 20-50% moisture remaining in the web after creping. The creping enhances the absorbent capacity and absorbent rate of the towel.
The conventional process for making soft paper towels is similar to the conventional process for making hand or wiper towels; however, creping of the fibrous web is done when moisture content has been reduced to 10% or less. An adhesive solution is also applied to the outer surface of the "Yankee" creping dryer so that the fibrous web adheres tightly to the surface of the dryer. The creped fibrous web requires no further drying in this process. The resulting soft towels possess high levels of absorbent capacity and absorbent rate; however, these soft towels are also very weak and tend to break apart when saturated with liquid. Accordingly, soft paper towels are not an adequate substitute for hand or wiper paper towels.
The creping step in the prior art processes for making hand or wiper towels and soft towels is a particularly costly step in those processes. Due primarily to the abrasiveness of the fibrous webs, the creping blades are quickly dulled and often have to be replaced. In addition to the cost of the replacement blades, there is lost production time when the paper making process must be shut down to replace the blades.
Therefore, there is a need for a hand or wiper paper towel which possesses a high level of strength as well as high levels of absorbent capacity, absorbent rate, and softness.