Paper making and fiber liberation – Processes and products – Non-uniform – irregular or configured web or sheet
Reexamination Certificate
1997-12-19
2001-05-15
Chin, Peter (Department: 1731)
Paper making and fiber liberation
Processes and products
Non-uniform, irregular or configured web or sheet
C162S134000, C162S135000, C162S158000, C162S184000
Reexamination Certificate
active
06231719
ABSTRACT:
BACKGROUND OF THE INVENTION
Recently a process has been disclosed in U.S. Pat. No 5,607,551 issued Mar.4, 1997 to Farrington, Jr. et al. which allows the production of soft absorbent tissue structures without the use of traditional Yankee dryer creping. Sheets produced by this uncreped throughdried process can be characterized as being very three dimensional with high bulk, high absorbent capacity and fast absorbent rate. However, because of the high degree of surface contour, such sheets can also abrade the skin. In addition, while the high absorbent capacity and fast absorbent rate of sheets produced in this manner can be ideal for some absorbent products, soft tissues such as facial and bathroom tissue often find advantages in a more controlled, even slow, absorbent rate while maintaining high absorbent capacity.
While it is known to provide tissues with lotions that can improve softness, the addition of such materials can decrease the thickness of the tissue sheets due to a partial collapse of the crepe structure when exposed to moisture and processing pressures.
Furthermore, the general approach in the industry has been that the greater the quantity of additive on the tissue, the greater the benefit. Contributing to this approach is the fact that particular additives may be absorbed into the tissue, leaving less additive on the surface to provide the intended benefit. One major drawback to the “more is better”philosophy is cost. Additives to address skin abrasion can represent a significant portion of the cost of a tissue sheet. Also, for some additives, relatively high addition levels can be difficult to manufacture.
Thus, there is first a need to enhance sheet softness and/or reduce the potential for skin abrasion with an economical, yet effective, surface additive without losing the thickness of the uncreped throughdried tissue. Secondly there is a need for a cost effective method to manufacture uncreped throughdried tissue products including such an additive.
SUMMARY OF THE INVENTION
It has now been discovered that, surprisingly, uncreped throughdried tissue products containing an additive adapted to reduce skin irritation and redness can be manufactured with substantially lower total add-on amounts without decreasing the effectiveness of the additive. Applicants have discovered that an array of primary delivery zones with a relatively high additive add-on amount in combination with supplementary delivery zones with a relatively lower add-on amount can be used effectively to maximize consumer benefit while minimizing the total amount of additive on the tissue.
In one embodiment, a tissue product is formed with one or more uncreped throughdried tissue plies and defines a major surface having a planar surface area. The tissue product comprises an additive composition disposed on the major surface in at least one primary delivery zone and at least one supplementary delivery zone. The primary delivery zone has a primary add-on level and the supplementary delivery zone has a supplementary add-on level. The supplementary add-on level is greater than zero and from about 0.5 to about 80 percent of the primary add-on level.
In another embodiment, a tissue product is formed with one or more uncreped throughdried tissue plies. The tissue product comprises an additive composition disposed on a major surface in at least one primary delivery zone having a primary add-on level and at least one supplementary delivery zone having a supplementary add-on level. The supplementary add-on level is greater than zero and the primary add-on level is greater than the supplementary add-on level. The primary delivery zone covers from about 30 to about 90 percent of the tissue surface area and the supplementary delivery zone covers from about 10 to about 70 percent of the tissue surface area.
The primary and supplementary add-on amounts, and the number, size, shape, and position of the primary and supplementary delivery zones, can be selected to maximize the overall benefit provided to the consumer while minimizing the total add-on amount.
The terms “primary add-on amount” and “primary add-on level” refer to the basis weight of additive composition in the primary delivery zone or zones, typically measured in grams per square meter (gsm). In contrast, the terms “supplementary add-on amount” and “supplementary add-on level” refer interchangeably to the basis weight of additive composition in the supplementary delivery zone or zones. Thus, for any given tissue including a surface additive composition segmented into zones having different add-on amounts, the zone or zones having higher add-on amounts are deemed the primary delivery zones and the zone or zones having lower add-on amounts are deemed the supplementary delivery zones. The primary and supplementary delivery zones may be used on one or both surfaces of the tissue.
For purposes of the present invention, the primary add-on amount is generally set as the level of the selected additive that provides a high degree of satisfaction on the part of the consumer. The supplementary add-on amount provides a lesser degree of consumer satisfaction than the primary add-on amount, but significantly, it still provides some degree of benefit. The actual basis weight values for the primary and supplementary add-on amounts may need to be determined by comparing the consumer benefits obtained from a series of test tissue products that differ from one another only in the additive add-on amount, each having a uniform application of the additive deposited on one surface or both surfaces. The primary add-on amount will be the same as or similar to the add-on amount on the test tissue products that deliver the desired level of consumer benefit. The supplementary add-on amount will then be greater than zero but less than the primary add-on amount.
The number, size, shape and position of the primary delivery zone or zones on a particular tissue are selected so as to obtain the same or substantially the same consumer benefit as would be obtainable from a tissue having a uniform add-on amount equal to the primary add-on amount. One or more supplementary delivery zones are provided on the tissue product so as not to detract from the benefit delivered by the primary delivery zones. The supplementary delivery zones allow for a reduction in the cost of the tissue product compared to what would result if the total coverage area included the additive composition at the primary add-on amount. It is theorized that “additive void areas,” that is, areas on the surface of the tissue that do not contain the additive composition, significantly detract from the benefit provided by the primary delivery zone or zones. The combination of primary and supplementary delivery zones is thought to allow delivery of the consumer benefit afforded by the primary add-on amount but at a lower cost.
By way of illustration, a single primary delivery zone may be centrally located on the tissue surface and comprise about 65 percent of the planar surface area of the tissue. A single supplementary delivery zone may completely surround the primary delivery zone and comprise about 35 percent of the planar surface area. In this embodiment, the primary delivery zone is centrally located to maximize the opportunity for the higher, primary add-on amount of additive to contact the skin during product use to yield maximum benefit. The supplementary delivery zone provides some benefit, and importantly does not detract from the benefit derived from the primary delivery zone. Such a tissue is believed to be capable of providing consumer benefits comparable to a tissue having a uniform additive add-on amount equal to the primary add-on amount centrally located over 100 percent of the planar surface area, and at a reduced cost.
By way of further illustration, the tissue product may comprise an alternating pattern of primary and supplementary delivery zones. This product as well is capable of providing the consumer benefits associated exclusively with the higher add-on amount, but at a reduced cost because the prim
Couture Marc David
Drozd Robert Timothy
Garvey Lee Patrick
Henderson Cynthia Watts
Charlier Patricia A.
Chin Peter
Gage Thomas M.
Kimberly--Clark Worldwide, Inc.
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