CA3005763A1

CA3005763A1 - Flushable fibrous structures

Info

Publication number: CA3005763A1
Application number: CA3005763A
Authority: CA
Inventors: Khosrow Parviz Mohammadi
Original assignee: Procter and Gamble Co
Current assignee: Procter and Gamble Co
Priority date: 2015-12-18
Filing date: 2016-12-14
Publication date: 2017-06-22
Anticipated expiration: 2036-12-14
Also published as: EP3390716A2; US20170175338A1; WO2017106299A3; CA3005763C; WO2017106299A2

Abstract

Flushable fibrous structure products, including sanitary tissue products, are described. As discussed in the background section, there is a relatively narrow desirable range of floatation/sink time that can be predicative of flushability success. Fibrous structures that float can have difficulty exiting a toilet bowl. And fibrous structures that sink too fast can cause a plug at the exit point of a toilet bowl. Thus, fibrous structures and sanitary tissue products comprising the same that do not float but sink sufficiently slow when placed into a toilet so as not to cause a plug are provided.

Description

2 DETAILED DESCRIPTION OF THE INVENTION
The following text sets forth a broad description of numerous different embodiments of the present invention. The description is to be construed as exemplary only and does not describe every possible embodiment since describing every possible embodiment would be impractical, if not impossible. And it will be understood that any feature, characteristic, component, composition, ingredient, product, step or methodology described herein can be deleted, combined with or substituted for, in whole or part, any other feature, characteristic, component, composition, ingredient, product, step or methodology described herein. Numerous alternative embodiments could be implemented, using either current technology or technology developed after the filing date of this patent, which would still fall within the scope of the claims.
It should also be understood that, unless a term is expressly defined in this specification using the sentence "As used herein, the term ______________________ is hereby defined to mean..." or a similar sentence, there is no intent to limit the meaning of that term, either expressly or by implication, beyond its plain or ordinary meaning, and such term should not be interpreted to be limited in scope based on any statement made in any section of this patent (other than the language of the claims). No term is intended to be essential to the present invention unless so stated. To the extent that any term recited in the claims at the end of this patent is referred to in this patent in a manner consistent with a single meaning, that is done for sake of clarity only so as to not confuse the reader, and it is not intended that such a claim term be limited, by implication or otherwise, to that single meaning. Finally, unless a claim element is defined by reciting the word "means" and a function without the recital of any structure, it is not intended that the scope of any claim element be interpreted based on the application of 35 U.S.C. 112, sixth paragraph.
"Fiber" as used herein means an elongate physical structure having an apparent length greatly exceeding its apparent diameter, i.e. a length to diameter ratio of at least about 10. Fibers having a non-circular cross-section and/or tubular shape are common; the "diameter" in this case may be considered to be the diameter of a circle having cross-sectional area equal to the cross-sectional area of the fiber. More specifically, as used herein, "fiber" refers to fibrous structure-making fibers. The present invention contemplates the use of a variety of fibrous structure-making fibers, such as, for example, natural fibers, such as trichome fibers and/or wood pulp fibers, or synthetic fibers, or any other suitable fibers, and any combination thereof.
"Fibrous structure" as used herein means a structure that comprises one or more fibers.
Non-limiting examples of processes for making fibrous structures include known wet-laid products comprising the same that do not float but sink sufficiently slow when placed into a toilet so as not to cause a plug.
Flushability evaluations can be made according to the Flushability Test methods described below. These methods can assess toilet bowl clearances during a flushing event, and can also assess the float and sink characteristics of a sanitary tissue product. Independent of the flushability assessments, the inventors have discovered that contact angle of a fibrous structure is one indicator of how well it will flush according to the present invention.
Some fibrous structures and sanitary tissue embodiments of the present invention have a contact angle of greater than or equal to 75 degrees, 80 degrees, 90 degrees, and 100 degrees.
While relatively high contact angles can be desirable, fibrous structures of the present invention should not float indefinitely when placed into a toilet bowl, as it can negatively impact ultimate flushability of the structure.
Fibrous structures of the present preferably comprise a fiber blend. The fibers blends typically include wood fibers, which can often be referred to as wood pulps include chemical pulps, such as kraft (sulfate) and sulfite pulps, as well as mechanical and semi-chemical pulps including, for example, groundwood, thermomechanical pulp, chemi-mechanical pulp (CMP), chemi-thermomechanical pulp (CTMP), neutral semi-chemical sulfite pulp (NSCS).
Chemical pulps, however, may be preferred since they impart a superior tactile sense of softness to tissue sheets made therefrom. Pulps derived from both deciduous trees (hereinafter, also referred to as "hardwood") and coniferous trees (hereinafter, also referred to as "softwood") may be utilized.
The hardwood and softwood fibers can be blended, or alternatively, can be deposited in layers to provide a stratified and/or layered web. U.S. Patent Nos. 4,300,981 and

3,994,771 disclose layering of hardwood and softwood fibers. Also applicable to the present invention are fibers derived from recycled paper, which may contain any or all of the above categories as well as other non-fibrous materials such as fillers and adhesives used to facilitate the original papermaking. The wood pulp fibers may be short (typical of hardwood fibers) or long (typical of softwood fibers). Non-limiting examples of short fibers include fibers derived from a fiber source selected from the group consisting of Acacia, Eucalyptus, Maple, Oak, Aspen, Birch, Cottonwood, Alder, Ash, Cherry, Elm, Hickory, Poplar, Gum, Walnut, Locust, Sycamore, Beech, Catalpa, Sassafras, Gmelina, Albizia, Anthocephalus, and Magnolia. Non-limiting examples of long fibers include fibers derived from Pine, Spruce, Fir, Tamarack, Hemlock, Cypress, and Cedar. Softwood fibers derived from the Test each of the samples in the same manner, recording the above measured values from each test. Average the values for each property obtained from the samples tested to obtain the reported value for that property.
Total Dry Tensile (TDT) = Peak Load MD Tensile (g/in) + Peak Load CD Tensile (g/in) The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as "40 mm" is intended to mean "about 40 mm."
The citation of any document, including any cross referenced or related patent or application and any patent application or patent to which this application claims priority or benefit thereof is not an admission that it is prior art with respect to any invention disclosed or claimed herein or that it alone, or in any combination with any other reference or references, teaches, suggests or discloses any such invention. Further, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document cited herein, the meaning or definition assigned to that term in this document shall govern.
While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.

Claims

What is claimed is:

1. A single or multi ply sanitary tissue for disposal in a toilet, the sanitary tissue comprising a fibrous structure comprising a contact angle value of greater than or equal to 75 degrees.

2. The sanitary tissue of Claim 1, wherein the fibrous structure comprises hydrophobic fibers.

3. The sanitary tissue of Claim 1, wherein the hydrophobic fibers comprise fibers harvested from a plant.

4. The sanitary tissue of Claim 4, wherein the plant is in the Stachys genus.

5. The sanitary tissue of Claim 1, wherein the fibrous structure comprises trichome fibers.

6. The sanitary tissue of Claim 1, wherein the fibrous structure comprises a fiber blend that comprises softwood fibers, hardwood fibers, and hydrophobic fibers.

7. The sanitary tissue of Claim 1, wherein sheets of the sanitary tissue do not float when placed into a toilet bowl.

8. The sanitary tissue of Claim 1, wherein a sheet of the sanitary tissue sinks in a time no faster than 2.5 seconds.

9. The sanitary tissue of Claim 1, wherein the fibrous structure comprises both hydrophobic fibers and a hydrophobic additive.

10. The sanitary tissue of Claim 9, wherein the hydrophobic fibers comprises trichome fibers and the hydrophobic additive comprises a silicone.

11. The sanitary tissue of Claim 1, wherein the fibrous structure further comprises a softener additive.

12. The sanitary tissue product of Claim 1, wherein the fibrous structure further comprises a temporary wet strength additive.

13. A single or multi ply sanitary tissue for disposal in a toilet, the sanitary tissue comprising a fibrous structure comprising a fiber blend of wood fibers and hydrophobic fibers, and a contact angle value of greater than or equal to about 85, wherein at least some of the hydrophobic fibers have a length of less than 100 microns.

14. The sanitary tissue of Claim 13, wherein the hydrophobic fibers comprise fibers harvested from a plant.

15. The sanitary tissue of Claim 14, wherein the plant is in the Stachys genus.

16. The sanitary tissue of Claim 14, wherein the fibrous structure further comprises a softener additive.

17. The sanitary tissue product of Claim 14, wherein the fibrous structure further comprises a temporary wet strength additive.

18. A single of multi ply sanitary tissue for disposal in a toilet, the sanitary tissue comprising a fibrous structure that comprises a fiber blend, the fiber blend comprises softwood fibers and hardwood fibers, wherein at least one of the following is included: i) hydrophobic fibers in the fibrous structure and ii) hydrophobic additive disposed on an outer surface of the fibrous structure, wherein 30 sheets of the sanitary tissue product does not float when placed into a toilet bowl, and wherein the 30 sheets of the sanitary tissue product clears a toilet bowl at a level of greater than 30% of the time according to the Flushability Test described herein.

19. The sanitary tissue of Claim 18, wherein the fibrous structure comprises hydrophobic fibers comprising trichome fibers.

20. The sanitary tissue of Claim 18, wherein at least some of the trichome fibers have a fiber length of less than 100 microns.