Stock material or miscellaneous articles – Structurally defined web or sheet – Continuous and nonuniform or irregular surface on layer or...
Reexamination Certificate
1999-08-27
2002-07-16
Kelly, Cynthia H. (Department: 1774)
Stock material or miscellaneous articles
Structurally defined web or sheet
Continuous and nonuniform or irregular surface on layer or...
C428S156000, C428S165000, C428S172000, C428S195100, C442S097000, C442S102000, C442S118000, C442S119000, C442S152000, C442S413000, C442S414000, C162S113000, C162S127000, C162S134000, C162S158000, C162S164400, C162S184000
Reexamination Certificate
active
06420013
ABSTRACT:
TECHNICAL FIELD
This invention relates, in general, to multi-ply soft tissue paper products; and more specifically, to multi-ply soft tissue paper products having a multi-region paper structure with a surface-applied chemical softeners applied to at least one of the regions.
BACKGROUND OF THE INVENTION
Sanitary paper tissue products are widely used. Such items are commercially offered in formats tailored for a variety of uses such as facial tissues, toilet tissues and absorbent towels.
All of these sanitary products share a common need, specifically to be soft to the touch. Softness is a complex tactile impression evoked by a product when it is stroked against the skin. The purpose of being soft is so that these products can be used to cleanse the skin without being irritating. Effectively cleansing the skin is a persistent personal hygiene problem for many people. Objectionable discharges of urine, menses, and fecal matter from the perineal area or otorhinolaryngogical mucus discharges do not always occur at a time convenient for one to perform a thorough cleansing, as with soap and copious amounts of water for example. As a substitute for thorough cleansing, a wide variety of tissue and toweling products are offered to aid in the task of removing from the skin and retaining such discharges for disposal in a sanitary fashion. Not surprisingly, the use of these products does not approach the level of cleanliness that can be achieved by the more thorough cleansing methods, and producers of tissue and toweling products are constantly striving to make their products compete more favorably with thorough cleansing methods.
Shortcomings in tissue products for example cause many to stop cleaning before the skin is completely cleansed. Such behavior is prompted by the harshness of the tissue, as continued rubbing with a harsh product can abrade the sensitive skin and cause severe pain. The alternative, leaving the skin partially cleansed, is chosen even though this often causes malodors to emanate and can cause staining of undergarments, and over time can cause skin irritations as well. Disorders of the anus, for example hemorrhoids, render the perianal area extremely sensitive and cause those who suffer such disorders to be particularly frustrated by the need to clean their anus without prompting irritation.
Accordingly, making soft tissue and toweling products has long been the goal of the engineers and scientists who are devoted to research into improving tissue paper. While softness is the paramount attribute affecting the desirability and effectiveness of a tissue paper product, it's achievement has often been pursued even at the expense of making performance impairing sacrifices.
For example, it is well known that there is an inverse relationship between softness of tissue paper products and the strength of those products. Strength is the ability of the product, and its constituent webs, to maintain physical integrity and to resist tearing, bursting, and shredding under use conditions. Tissue paper webs are normally moderated in strength to the minimum level required in order to maximize the potential for softness.
Another area which has been long been sacrificed to maximize softness is texture. A tissue paper web is typically sided due to the processes used to produce paper products. Sidedness is the tendency for one side of the paper web to be smoother than the other side. For example, in a so-called Yankee-type or dry creped process, there is substantial smoothing achieved by contact of one side of the sheet with the Yankee. Analogously, in an uncreped process, the different drying fabrics with which the sides of the web are in contact during production have different smoothness characteristics; these differences are replicated in the surfaces of the resultant product. The resultant smooth versus. textured side of tissue paper webs present the manufacturer of tissue paper products with a dilemma when the tissue paper webs are used to assemble a multi-ply product. For example, in common two-ply tissue product, it is typical practice to orient the smoother side of the individual tissue paper webs toward the outward facing surfaces. This orientation is selected to maximize softness by maximizing the smoothness of the tissue paper product. Smoothness is one characteristic used by consumers to determine relative softness and is a tactilely perceivable difference in texture (lowering texture increases smoothness) resulting from the intrinsic nature of the tissue papermaking process. Those skilled in the art will recognize that the perceived softness improvement from orienting the smoother side out is accompanied by a sacrifice in the cleaning potential (or perceived cleaning potential) of the product that would be provided by the rougher texture (An example of the recognition by the art of the value of texture to cleaning can be found in U.S. Pat. No. 4,112,167, issued to Dake, et al. on Sep. 5, 1978, which describes tissue structures having surface depressions, the structure being treated with a lipophilic cleansing emollient at a level of between about 10 percent and about 150 percent of the tissue weight). Notwithstanding the sacrifice in cleaning potential, the art has consistently chosen to convert multi-ply products smooth side out because of the softness deficiencies of products converted with the rougher side out. Thus, it would be highly desirable to convert the tissue paper webs into multi-ply products so that textured surfaces face outward, if softness could be maintained.
Various methods have been undertaken to increase softness of tissue paper webs. For, example, one area that has been exploited in this regard has been to select and modify cellulose fiber morphologies and engineer paper structures to take optimum advantages of the various available morphologies. Applicable art in this area includes: Vinson et. al. in U.S. Pat. No. 5,228,954, issued Jul. 20, 1993, Vinson in U.S. Pat. No. 5,405,499, issued Apr. 11, 1995, Cochrane et al. in U.S. Pat. No. 4,874,465 issued Oct. 17, 1989, and Hermans, et. al. in U.S. Statutory Invention Registration H 1672, published on Aug. 5, 1997, all of which disclose methods for selecting or upgrading fiber sources to tissue and toweling of superior properties. Applicable art is further illustrated by Carstens in U.S. Pat. No. 4,300,981, issued Nov. 17, 1981, which discusses how fibers can be incorporated to be compliant to paper structures so that they have maximum softness potential. While such techniques as illustrated by these prior art examples are recognized broadly, they can only offer some limited potential to make tissues truly effective comfortable cleaning products.
Another area which has received a considerable amount of attention is the addition of chemical softening agents (also referred to herein as “chemical softeners”) to tissue and toweling products.
As used herein, the term “chemical softening agent” refers to any chemical ingredient which improves the tactile sensation perceived by the consumer who holds a particular paper product and rubs it across the skin. Although somewhat desirable for towel products, softness is a particularly important property for facial and toilet tissues. Such tactile perceivable softness can be characterized by, but is not limited to, friction, flexibility, and smoothness, as well as subjective descriptors, such as a feeling like lubricious, velvet, silk or flannel. which imparts a lubricious feel to tissue. This includes, for exemplary purposes only, basic waxes such as paraffin and beeswax and oils such as mineral oil and silicone oil as well as petrolatum and more complex lubricants and emollients such as quaternary ammonium compounds with long alkyl chains, functional silicones, fatty acids, fatty alcohols and fatty esters.
The field of work in the prior art pertaining to chemical softeners has taken two paths. The first path is characterized by the addition of softeners to the tissue paper web during its formation either by adding an attractive ingredient to the vats of pulp whi
Ho-Kleinwaechter Monica
Trokhan Paul Dennis
Vinson Kenneth Douglas
Gray J. M.
Kelly Cynthia H.
Milbrada Edward J.
Murphy Stephen T.
The Procter & Gamble & Company
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