Paper making and fiber liberation – Processes and products – Running or indefinite length work forming and/or treating...
Reexamination Certificate
1998-12-17
2002-08-13
Fortuna, Jose (Department: 1731)
Paper making and fiber liberation
Processes and products
Running or indefinite length work forming and/or treating...
C162S206000, C162S164100, C162S164300, C162S168300, C162S158000
Reexamination Certificate
active
06432272
ABSTRACT:
FIELD OF THE INVENTION
The present invention generally relates to absorbent fibrous paper-based structures such as hand towels, tissues, wipers, and the like, and more specifically, to compressed absorbent fibrous structures.
BACKGROUND OF THE INVENTION
Absorbent fibrous structures, such as hand towels, wipers, tissues, and the like, as well as various components for other fluid-handling and absorbing materials are well known in the art. These structures may be formed from materials that allow them to be absorbent so that the structures will typically absorb, in varying degrees, liquids from one's body or elsewhere. Such liquids may include water, coffee, milk, cleaning formulations, oil, etc., and various bodily fluids such as blood, urine, nasal discharge and other body exudates. Various natural wood pulp fibers, as well as synthetic fibers, may be useful for making such fibrous structures.
Often, absorbent fibrous structures such as hand towels (commonly referred to as “paper towels”) will be wound onto various types of paperboard cores. These paperboard cores, with towels wound onto them, may be placed in various types of dispensing mechanisms to allow users to dispense one or more towel at a time from the roll. The rolls of towels may be perforated at various points to divide bulk rolls into single sheet towels. During dispensing, a user may tear one or more towels along the perforation lines for use. When the towels are not perforated, teeth may be provided on the dispenser for assisting in tearing the roll into individual towels.
Due to the bulkiness of the paper rolls, only a defined number or length of towels, and thus a defined number of drying uses, may be available from each roll. This number of drying uses may be typically referred to as the number of hand dries available.
The size of the paper rolls, and thus the resulting number of hand dries, may be limited by the size of the dispensers in which the rolls may be kept. Most standard-sized roll towel dispensers may accept a paper towel roll of approximately 8 to 9 inches in diameter. Often, use of the paper towels from the roll must be monitored and the dispenser must be refilled frequently in order to prevent depletion of the product.
Some paper towels, on the other hand, may be provided in a folded condition with multiple towels stacked on top of one another. In such arrangements, a single towel may be dispensed one at a time. Often, like the roll towel dispensers, the dispensers in which folded towels are stacked and dispensed also may have a limited capacity and must, likewise, be monitored and refilled frequently.
Towel run-out occurs when the towels within a dispenser are exhausted and a janitor has not yet replenished the dispenser with a fresh or additional supply of new towels. Towel run-out may be one of the most common complaints from hand towel end users. Preventing towel run-out may require either more frequent visits by the janitor or the addition of more towels in the dispenser. The former solution is most likely not desired by towel end users or the entities that purchase the towels for end use because an increase in janitorial visits obviously increases labor costs. It seems that the latter solution has not heretofore been workable because of the fixed sizes of the dispensers and the thicknesses of the typical towels.
Even when rolls of towels are added on a frequent basis, the presently-employed roll towels may result in significant waste. Often, it will be necessary to replace a roll of towels prior to completely using the entire roll in order to prevent towel run-out. The amount of towels remaining on the roll may not justify continued utilization of the remainder of towels on the roll and, thus, the remainder of the yet-to-be-used towels are often discarded along with the core.
It has generally been perceived that the bulkier, or thicker, that a paper towel, tissue, or wiper is, then the more absorbent and “softer” it is. While such attributes are desirable and may be obtained by creating fibrous structures with greater thicknesses, the additional thickness creates numerous disadvantages. For example, as the thickness of a towel increases, the number or length of towels, and thus the number of drying uses, that can be placed inside a standard dispenser decreases.
Another consideration that is a disadvantage when using conventional-sized towels is that there is a defined number of hand dries per case of towel rolls or case of folded towel packages. It would be desirable from a shipping cost standpoint (both freight and shipping materials cost) and from a storage standpoint to fit more hand dries into each case of towels. In particular, the end user would need to store fewer cases of towels at its facilities if more hand dries could be found in a case.
Moreover, when using rolled towels, the inner core upon which the towels are wound must be disposed of. The more towels that can be placed on a roll, the less frequent is the disposal of such cores. If additional numbers of towels could be wound onto a roll, conservation and recycling efforts could be enhanced by allowing a core to be used for a longer period of time.
The present invention addresses some of the needs outlined above and provides an improvement to towel run-out and excessive waste by providing more towels within a standard-sized towel dispenser.
U.S. Pat. No. 5,779,860 to Hollenberg et al., which is commonly owned by the assignee of the present invention is directed to a product and process that utilizes compression techniques to increase the density of and decrease the caliper of various webs so that space-saving towels of the type discussed herein may be obtained. However, the absorbent structures discussed therein are compressed into structures that will have a thickness of less than about 50% of the thickness of the original uncompressed structure. In other words, the uncompressed webs of Hollenberg et al. are compressed so as to increase their densities at least about 50%. For example, an uncompressed web having a density of about 0.2 grams per cubic centimeter may be compressed so that its density is increased to about 0.3 grams per cubic centimeter or greater. In particular, the webs containing high yield pulps, such as bleached chemithermomechanical pulp, may be compressed at such ranges and still maintain their structure and wet strength. In fact, when saturated with water, the density of such compressed webs will decrease about 20 percent or greater. As discussed herein the present inventive webs provide certain of the advantages of the webs described in Hollenberg et al., but are formed from different materials and with different processes.
SUMMARY OF THE INVENTION
In accordance with the present invention, certain advantages are accomplished by compressing a paper web that has a temporary or permanent wet strength. The resulting paper web may allow more feet of towels to be added to a towel roll (or more towels to be added to a stack of folded towels) without substantially increasing the diameter of the roll (or the thickness of the stack of towels). More sheets on a roll (or more towels in a folded towel stack) may mean fewer roll (or folded towel) changes and replenishings for the end user. Fewer rolls per case and a reduced case size may translate into fewer cores and shipping cases to be disposed of. The invention may also allow more towels to be shipped on the same truck or placed into a standard shipping storage compartment.
A compression force may be applied to the paper web to provide a compressed paper web having a certain reduced caliper. The amount of compression applied to the paper web may be expressed as a “caliper compression ratio” as defined herein.
Desirably, the caliper compression ratio will be between about 0.1 and about 0.5 in order to meet the requirements of the present invention.
In addition, the compressed webs of the present invention will have a water absorbent capacity of at least about 70% of the water absorbent capacity of the same web prior to compression, desirably at least about 80
Hollenberg David H.
Hsu Jay C.
Hu Sheng H.
Kuchibhotla Anand
McConnell Wesley J.
Dority & Manning P.A.
Fortuna Jose
Kimberly--Clark Worldwide, Inc.
LandOfFree
Compressed absorbent fibrous structures does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Compressed absorbent fibrous structures, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Compressed absorbent fibrous structures will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2913699