Stock material or miscellaneous articles – Composite – Of silicon containing
Reexamination Certificate
2002-09-19
2004-03-16
Loney, Donald J. (Department: 1772)
Stock material or miscellaneous articles
Composite
Of silicon containing
C428S153000, C428S154000, C428S156000, C428S166000, C428S172000, C162S164400
Reexamination Certificate
active
06706410
ABSTRACT:
TECHNICAL FIELD
This invention relates to a soft tissue paper having the combination of softness, strength, absorbency and reopenability.
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.
It has long been recognized that four important physical attributes of these products are their strength, their softness, their absorbency, and their lint resistance. Strength is the ability of the product to maintain physical integrity and to resist tearing, bursting and shredding under use conditions, particularly when wet. Softness is the tactile sensation perceived by the consumer as she holds a particular product, rubs it across her skin, or crumples it with her hand. Absorbency is the measure of the ability of a product to absorb quantities of liquid, particularly aqueous solutions or dispersions. Lint resistance is the ability of the fibrous product to bind together under use conditions, especially when wet. The literature is replete with examples of research and development efforts to improve one or more of these basic attributes, showing the delicacy of the balance of these attributes. A desire to improve a fifth physical attribute, while maintaining the high beneficial performance as to the other four attributes, dramatically adds to the complexity of the development process.
Despite this additional complexity, consumers continue to demand and appreciate additional benefits. One of these new physical attributes which creates a consumer benefit is the ease of reopening a paper tissue product once it is wet. This is especially true of more durable tissue products typically used for household cleaning, such as paper towels.
It is the object of the present invention to provide a tissue paper product with increased reopenability which has enhanced softness and which does not substantially sacrifice absorbency, strength, and lint resistance.
SUMMARY OF THE INVENTION
The present invention relates to a soft tissue paper product having two outer surfaces, the soft tissue paper product comprising:
a) one or more plies of a tissue paper having a total wet tensile strength of at least about 200 g/in; and
b) a chemical softening composition deposited on at least one outer surface of said tissue, said chemical softening composition comprising a silicoxane-polyalkyleneoxide copolymer comprising greater than about 10% by weight of polyalkyleneoxide;
wherein the copolymer has a surface tension of less than about 40 mN/m at 0.1%, has a Ross Miles foam height of less than about 60 mm, and has an HLB of greater than about 4.
All percentages, ratios and proportions herein are by weight, unless otherwise specified.
All documents cited are, in relevant part, incorporated herein by reference; the citation of any document is not to be construed as an admission that it is prior art with respect to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The Soft Tissue Paper Product
The present invention provides a soft tissue paper product which has improved reopenability. The paper product comprises one or more plies of tissue paper and a chemical softening composition.
Tissue Paper
The present invention is applicable to tissue paper in general, including but not limited to: conventionally felt-pressed tissue paper; pattern, densified tissue paper, and high-bulk, uncompacted tissue paper. The tissue paper may be of a homogenous or multilayered construction; and tissue paper products made therefrom may be of a single-ply or multi-ply construction. The soft tissue paper product preferably has a basis weight of between about 10 g/m
2
and about 80 g/m
2
, and density of about 0.60 g/cc or less. Preferably, the basis weight will range from about 20 g/m
2
to about 65 g/m
2
and more preferably from about 30 g/m
2
to about 50 g/m
2
; and the density will be about 0.30 g/cc or less. Most preferably, the density will be between about 0.04 g/cc and about 0.20 g/cc.
Conventionally pressed tissue paper and methods for making such paper are known in the art. Such paper is typically made by depositing a papermaking furnish on a foraminous forming wire. This forming wire is often referred to in the art as a Fourdrinier wire. Once the furnish is deposited on the forming wire, it is referred to as a web. Overall, water is removed from the web by vacuum, mechanical pressing and thermal means. The web is dewatered by pressing the web and by drying at elevated temperature. The particular techniques and typical equipment for making webs according to the process just described are well known to those skilled in the art. In a typical process, a low consistency pulp furnish is provided in a pressurized headbox. The headbox has an opening for delivering a thin deposit of pulp furnish onto the Fourdrinier wire to form a wet web. The web is then typically dewatered to a fiber consistency of between about 7% and about 45% (total web weight basis) by vacuum dewatering and further dried by pressing operations wherein the web is subjected to pressure developed by opposing mechanical members, for example, cylindrical rolls. The dewatered web is then further pressed and dried by a stream drum apparatus known in the art as a Yankee dryer. Pressure can be developed at the Yankee dryer by mechanical means such as an opposing cylindrical drum pressing against the web. Multiple Yankee dryer drums may be employed, whereby additional pressing is optionally incurred between the drums. The tissue paper structures which are formed are referred to hereinafter as conventional, pressed, tissue paper structures. Such sheets are considered to be compacted, since the web is subjected to substantial overall mechanical compression forces while the fibers are moist and are then dried while in a compressed state. The resulting structure is strong and generally of singular density, but very low in bulk, absorbency and in softness.
Pattern densified tissue paper is characterized by having a relatively high-bulk field of relatively low fiber density and an array of densified zones of relatively high fiber density. The high-bulk field is alternatively characterized as a field of pillow regions. The densified zones are alternatively referred to as knuckle regions. The densified zones may be discretely spaced within the high-bulk field or may be interconnected, either fully or partially, within the high-bulk field. Preferred processes for making pattern densified tissue webs are disclosed in U.S. Pat. No. 3,301,746, issued to Sanford and Sisson on Jan. 31, 1967, U.S. Pat. No. 3,974,025, issued to Ayers on Aug. 10, 1976, and U.S. Pat. No. 4,191,609, issued to Trokhan on Mar. 4, 1980, and U.S. Pat. No. 4,637,859, issued to Trokhan on Jan. 20, 1987.
In general, pattern densified webs are preferably prepared by depositing a papermaking furnish on a foraminous forming wire such as a Fourdrinier wire to form a wet web and then juxtaposing the web against an array of supports as it is transferred from the forming wire to a structure comprising such supports for further drying. The web is pressed against the array of supports, thereby resulting in densified zones in the web at the locations geographically corresponding to the points of contact between the array of supports and the wet web. The remainder of the web not compressed during this operation is referred to as the high-bulk field. This high-bulk field can be further dedensified by application of fluid pressure, such as with a vacuum type device or a blow-through dryer, or by mechanically pressing the web against the array of supports. The web is dewatered, and optionally predried, in such a manner so as to substantially avoid compression of the high-bulk field. This is preferably accomplished by fluid pressure, such as with a vacuum type device or blow-through dryer, or alternately by mechanically pressing the web against an array of supports wherein the high-bulk field is not compressed. The operations of dewatering, optional predrying and for
Douglas Brian David
Horenziak Steven Anthony
Ostendorf Ward William
Loney Donald J.
Murphy Stephen T.
Patel Ken K.
The Procter & Gamble & Company
Weirich David M.
LandOfFree
Soft tissue paper having a softening composition containing... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Soft tissue paper having a softening composition containing..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Soft tissue paper having a softening composition containing... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3232027