U.S. patent application number 11/820511 was filed with the patent office on 2008-01-03 for nonwoven fibrous structure comprising a multifilament fiber.
Invention is credited to Arnold William Trueman, Kenneth Douglas Vinson.
Application Number | 20080003913 11/820511 |
Document ID | / |
Family ID | 38846075 |
Filed Date | 2008-01-03 |
United States Patent
Application |
20080003913 |
Kind Code |
A1 |
Vinson; Kenneth Douglas ; et
al. |
January 3, 2008 |
Nonwoven fibrous structure comprising a multifilament fiber
Abstract
Fibrous structures including a fiber and/or a multifilament
fiber, sanitary tissue products employing such fibrous structures
and methods for making such fibrous structures are provided.
Inventors: |
Vinson; Kenneth Douglas;
(Toone, TN) ; Trueman; Arnold William; (Cedar
Grove, TN) |
Correspondence
Address: |
THE PROCTER & GAMBLE COMPANY;INTELLECTUAL PROPERTY DIVISION - WEST BLDG.
WINTON HILL BUSINESS CENTER - BOX 412, 6250 CENTER HILL AVENUE
CINCINNATI
OH
45224
US
|
Family ID: |
38846075 |
Appl. No.: |
11/820511 |
Filed: |
June 20, 2007 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60817321 |
Jun 29, 2006 |
|
|
|
Current U.S.
Class: |
442/344 ;
162/109; 57/288 |
Current CPC
Class: |
D21H 11/12 20130101;
D21H 27/002 20130101; D21H 15/06 20130101; D21H 25/14 20130101;
Y10T 442/619 20150401 |
Class at
Publication: |
442/344 ;
162/109; 57/288 |
International
Class: |
D04H 1/00 20060101
D04H001/00 |
Claims
1. A nonwoven fibrous structure comprising a multifilament
fiber.
2. The fibrous structure according to claim 1 wherein the
multifilament fiber is selected from the group consisting of:
twisted multifilaments, tow multifilaments and mixtures
thereof.
3. The fibrous structure according to claim 1 wherein the
multifilament fiber comprises two or more monofilaments.
4. The fibrous structure according to claim 3 wherein the
monofilaments are selected from the group consisting of natural
fibers, non-naturally occurring fibers and mixtures thereof.
5. The fibrous structure according to claim 3 wherein the
multifilament fiber exhibits an average fiber diameter of at least
about 1.2 times the average fiber diameter of the largest average
fiber diameter monofilament present in the fibrous structure.
6. The fibrous structure according to claim 1 wherein the
multifilament fiber exhibits an average effective fiber diameter of
at least about 30 microns.
7. The fibrous structure according to claim 1 wherein the
multifilament fiber is associated with an ingredient and/or
characteristic of the fibrous structure.
8. A single- or multi-ply sanitary tissue product comprising a
fibrous structure according to claim 1.
9. A method for making a fibrous structure according to claim 1,
the method comprising the step of depositing a fibrous slurry
comprising a multifilament fiber on a forming belt such that the
fibrous structure is formed.
10. A method for making a nonwoven fibrous structure according to
claim 7, the method comprising the steps of incorporating a
multifilament fiber into a fibrous structure wherein the
multifilament fiber is associated with an ingredient and/or
characteristic of the fibrous structure such that a consumer is
able to determine by looking at the multifilament fiber that the
fibrous structure and/or sanitary tissue product comprising such
fibrous structure contains a certain ingredient and/or exhibits a
certain characteristic.
11. A nonwoven fibrous structure comprising a fiber wherein the
fiber is associated with an ingredient and/or characteristic of the
fibrous structure.
12. A method for making a nonwoven fibrous structure according to
claim 11, the method comprising the steps of incorporating a fiber
into a fibrous structure wherein the fiber is associated with an
ingredient and/or characteristic of the fibrous structure such that
a consumer is able to determine by looking at the fiber that the
fibrous structure and/or sanitary tissue product comprising such
fibrous structure contains a certain ingredient and/or exhibits a
certain characteristic.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional
Application No. 60/817,321 filed Jun. 29, 2006.
FIELD OF THE INVENTION
[0002] The present invention relates to nonwoven fibrous
structures, more particularly to nonwoven fibrous structures
comprising multifilament fibers, methods for making such fibrous
structures and sanitary tissue products employing such fibrous
structures.
BACKGROUND OF THE INVENTION
[0003] Unlike woven fibrous structure, such as textiles, nonwoven
fibrous structures have not employed multifilament fibers. Nonwoven
fibrous structures have conventionally been made of monofilament
fibers. Wood pulp fibers, staple synthetic fibers, continuous
polymeric fibers all have been used in their monofilament form to
produce fibrous structures. No multifilament fibers have been used
in the past in nonwoven fibrous structures.
[0004] Accordingly, there is a need for nonwoven fibrous structures
comprising multifilament fibers, methods for making such fibrous
structures and sanitary tissue products comprising such fibrous
structures.
SUMMARY OF THE INVENTION
[0005] The present invention fulfills the needs described above by
providing a fibrous structure comprising a multifilament fiber, a
method for making such a fibrous structure and a sanitary tissue
product comprising such a fibrous structure.
[0006] In one example of the present invention, a nonwoven fibrous
structure comprising a multifilament fiber is provided.
[0007] In another example of the present invention, a nonwoven
fibrous structure comprising a fiber and/or a multifilament fiber
wherein the fiber and/or the multifilament fiber is associated with
an ingredient (other than the fiber or multifilament itself) and/or
characteristic present in the fibrous structure, is provided.
[0008] In yet another example of the present invention, a method
for making a nonwoven fibrous structure, the method comprising the
steps of incorporating a fiber and/or multifilament fiber into a
fibrous structure wherein the fiber and/or multifilament fiber is
associated with an ingredient and/or characteristic of the fibrous
structure such that a consumer is able to determine by looking at
the fiber and/or the multifilament fiber that the fibrous structure
and/or sanitary tissue product comprising such fibrous structure
contains a certain ingredient and/or exhibits a certain
characteristic, is provided.
[0009] In another example of the present invention, a method for
making a nonwoven fibrous structure comprising a multifilament
fiber, wherein the method comprises forming a nonwoven fibrous
structure from a fibrous slurry and/or fibrous composition
comprising a multifilament fiber, is provided.
[0010] A fibrous slurry as used herein means a mixture of
multifilaments and/or monofilaments. Such mixtures of
multifilaments and/or monofilaments may be used in wet laid process
or an air laid process
[0011] In yet another example of the present invention, a single-
or multi-ply sanitary tissue product comprising a nonwoven fibrous
structure according to the present invention, is provided.
[0012] Accordingly, the present invention provides nonwoven fibrous
structures comprising a multifilament fiber, methods for making
such a fibrous structure, and sanitary tissue products comprising
such a fibrous structure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a schematic representation of a multifilament
fiber in accordance with the present invention;
[0014] FIG. 2 is a schematic representation of a fibrous structure
in accordance with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Definitions
[0015] "Multifilament fiber" as used herein means a fiber that
comprises two or more monofilaments that are substantially
unbonded, but physically associated with one another to form a
unitary structure. Nonlimiting examples of suitable multifilament
fibers may be derived from yarns (continuous strands of twisted
monofilaments) or from tow (an untwisted bundle of continuous
filaments) most preferably by cutting such yarns or tow into
papermaking length. The dispersion energy from the papermaking
operation is insufficient to separate the multifilament fibers.
Groups of fibers with substantial bonding among the filaments,
including but not limited to such as nits, shives, and flakes, are
not multifilament fibers but rather are termed herein
"bonded-multifilament fibers".
[0016] The multifilament fiber may exhibit a length of at least
about 1 mm. The multifilament fiber may exhibit any shape, for
example it may be substantially cylindrical in shape. The
multifilament fiber may exhibit an average effective diameter that
is at least 1.2 times and/or at least 1.4 times and/or at least 1.5
times and/or at least 2 times and/or at least 10 times the average
effective diameter of any monofilaments within a fibrous structure.
Effective diameter means the calculated diameter based on the
diameter of a circle having the same area as the area of the
filament or multifilament in question. In one example, the
multifilament fiber exhibits a length of less than about 12.70 cm
(5 inches) and/or less than about 10.16 cm (4 inches) and/or less
than about 7.62 cm (3 inches) and/or less than about 5.08 cm (2
inches) and/or less than about 2.54 cm (1 inch).
[0017] In one example, the multifilament fiber of the present
invention exhibits an average effective diameter of at least about
30 microns and/or at least about 100 microns and/or at least about
500 microns.
[0018] The multifilament fibers of the present invention may
comprise natural fibers, non-naturally occurring fibers, such as
spun cellulose fibers and/or spun starch fibers, and/or other
synthetic fibers, such as polymeric fibers including but not
limited to nylon fibers, polyester fibers, polyolefin fibers and
combinations thereof.
[0019] In one example, at least one type of multifilament fiber of
the present invention is different in color than the other types of
multifilament fibers and the monofilament fibers comprising the
fibrous structure of the present invention. Preferably the color
difference is sufficient to render the multifilament fiber visually
discernible.
[0020] As shown in FIG. 1, a multifilament fiber 10, which is in
the form of a cut yarn, comprises two or more monofilaments 12. In
this example of a multifilament fiber, the multifilament fiber 10
is in the form of sheaves characterized by frayed ends 14, which
are present on at least one end 16 of the multifilament fiber
10.
[0021] A multifilament fiber may be a bonded multifilament fiber
and/or a non-bonded multifilament fiber.
[0022] "Bonded multifilament fiber" is an assembly of monofilaments
that are physically attached to one another directly or indirectly
(such as via a bonding agent), to form a bonded multifilament
fiber. Nonlimiting examples of bonded multifilament fibers include
flakes, nit and shives.
[0023] "Non-bonded multifilament fiber" is an assembly of
monofilaments that are in contact with one another at least one
point along their lengths but are not physically attached to one
another. Nonlimiting examples of non-bonded multifilament fibers
include yarn (monofilaments twisted about one another along their
lengths) and tow (monofilaments not twisted about one another along
their lengths).
[0024] In one example, the multifilament fibers of the present
invention are used in the fibrous structures of the present
invention in the form of cut yarn and/or cut tow that exhibit
suitable lengths for inclusion in the fibrous structures of the
present invention.
[0025] "Monofilament Fiber" as used herein means an elongate
particulate having an apparent length greatly exceeding its
apparent width, i.e. a length to diameter ratio of at least about
10. More specifically, as used herein, "fiber" refers to
papermaking fibers. The present invention contemplates the use of a
variety of papermaking fibers, such as, for example, natural fibers
or synthetic fibers, or any other suitable fibers, and any
combination thereof. Papermaking fibers useful in the present
invention include cellulosic fibers commonly known as wood pulp
fibers. Applicable wood pulps include chemical pulps, such as
Kraft, sulfite, and sulfate pulps, as well as mechanical pulps
including, for example, groundwood, thermomechanical pulp and
chemically modified thermomechanical pulp. 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
web. U.S. Pat. No. 4,300,981 and U.S. Pat. No. 3,994,771 are
incorporated herein by reference for the purpose of disclosing
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.
[0026] In addition to the various wood pulp fibers, other
cellulosic fibers such as cotton linters, rayon, and bagasse can be
used in this invention. Synthetic fibers and/or non-naturally
occurring fibers, such as polymeric fibers, can also be used.
Elastomeric polymers, polypropylene, polyethylene, polyester,
polyolefin, and nylon, can be used. The polymeric fibers can be
produced by spunbond processes, meltblown processes, and other
suitable methods known in the art.
[0027] An embryonic fibrous web can be typically prepared from an
aqueous dispersion of papermaking fibers, though dispersions in
liquids other than water can be used. The fibers are dispersed in
the carrier liquid to have a consistency of from about 0.1 to about
0.3 percent. It is believed that the present invention can also be
applicable to moist forming operations where the fibers are
dispersed in a carrier liquid to have a consistency of less than
about 50% and/or less than about 10%.
[0028] "Fibrous structure" as used herein means a structure that
comprises one or more multifilament fibers. In one example, a
fibrous structure according to the present invention means an
orderly arrangement of multifilament fibers alone or in combination
with monofilament fibers within a structure in order to perform a
function. Nonlimiting examples of fibrous structures of the present
invention include composite materials (including reinforced
plastics and reinforced cement), paper, fabrics (including woven,
knitted, and non-woven), and absorbent pads (for example for
diapers or feminine hygiene products). A bag of loose fibers is not
a fibrous structure in accordance with the present invention.
[0029] "Nonwoven" or "Nonwoven fibrous structure" as used herein
means a web that is produced by a process other than knitting or
some other woven process. A nonwoven fibrous structure is a web
that comprises a plurality of fiber and/or monofilaments and/or
multi-filaments that is produced by a process other than knitting
or some other woven process.
[0030] Nonlimiting examples of processes for making nonwoven
fibrous structures include known wet-laid papermaking processes and
air-laid papermaking processes. Such processes typically include
steps of preparing a fiber composition in the form of a suspension
in a medium, either wet, more specifically aqueous medium, or dry,
more specifically gaseous, i.e. with air as medium. The aqueous
medium used for wet-laid processes is oftentimes referred to as a
fiber slurry. The fibrous suspension is then used to deposit a
plurality of fibers onto a forming wire or belt such that an
embryonic fibrous structure is formed, after which drying and/or
bonding the fibers together results in a fibrous structure. Further
processing the fibrous structure may be carried out such that a
finished fibrous structure is formed. For example, in typical
papermaking processes, the finished fibrous structure is the
fibrous structure that is wound on the reel at the end of
papermaking, and may subsequently be converted into a finished
product, e.g. a sanitary tissue product.
[0031] The fibrous structures of the present invention may be
homogeneous or may be layered. If layered, the fibrous structures
may comprise at least two and/or at least three and/or at least
four and/or at least five layers.
[0032] "Sanitary tissue product" as used herein means a soft, low
density (i.e. <about 0.15 g/cm3) web useful as a wiping
implement for post-urinary and post-bowel movement cleaning (toilet
tissue), for otorhinolaryngological discharges (facial tissue), and
multi-functional absorbent and cleaning uses (absorbent towels).
The sanitary tissue product may be convolutedly wound upon itself
about a core or without a core to form a roll of sanitary tissue
product.
[0033] In one example, the sanitary tissue product of the present
invention comprises a fibrous structure according to the present
invention.
[0034] "Basis Weight" as used herein is the weight per unit area of
a sample reported in lbs/3000 ft.sup.2 or g/m.sup.2. Basis weight
is measured by preparing one or more samples of a certain area
(m.sup.2) and weighing the sample(s) of a fibrous structure
according to the present invention and/or a paper product
comprising such fibrous structure on a top loading balance with a
minimum resolution of 0.01 g. The balance is protected from air
drafts and other disturbances using a draft shield. Weights are
recorded when the readings on the balance become constant. The
average weight (g) is calculated and the average area of the
samples (m.sup.2). The basis weight (g/m.sup.2) is calculated by
dividing the average weight (g) by the average area of the samples
(m.sup.2).
[0035] "Machine Direction" or "MD" as used herein means the
direction parallel to the flow of the fibrous structure through the
papermaking machine and/or product manufacturing equipment.
[0036] "Cross Machine Direction" or "CD" as used herein means the
direction perpendicular to the machine direction in the same plane
of the fibrous structure and/or paper product comprising the
fibrous structure.
[0037] "Ply" or "Plies" as used herein means an individual fibrous
structure optionally to be disposed in a substantially contiguous,
face-to-face relationship with other plies, forming a multiple ply
fibrous structure. It is also contemplated that a single fibrous
structure can effectively form two "plies" or multiple "plies", for
example, by being folded on itself.
[0038] As used herein, the articles "a" and "an" when used herein,
for example, "an anionic surfactant" or "a fiber" is understood to
mean one or more of the material that is claimed or described.
[0039] All percentages and ratios are calculated by weight unless
otherwise indicated. All percentages and ratios are calculated
based on the total composition unless otherwise indicated.
[0040] Unless otherwise noted, all component or composition levels
are in reference to the active level of that component or
composition, and are exclusive of impurities, for example, residual
solvents or by-products, which may be present in commercially
available sources.
Fibrous Structure
[0041] The fibrous structures of the present invention comprise one
or more fibers and/or one or more multifilament fibers.
[0042] When present, the fibrous structure may comprise at least
about 0.1% by weight, on a dry fibrous structure basis of a
multifilament fiber. In one example, the fibrous structure may
comprise at least about 0.1% and/or at least about 0.2% and/or at
least about 0.4% and/or at least about 1% to about 25% and/or to
about 10% and/or to about 5% and/or to about 2.5% by weight, on a
dry fibrous structure basis of a multifilament fiber.
[0043] In addition to the multifilament fiber, the fibrous
structures of the present invention may comprise one or more
monofilament fibers. In addition to the multifilament fiber and
monofilament fibers, if any, the fibrous structures of the present
invention may comprise any suitable ingredients known in the art.
Nonlimiting examples of suitable ingredients that may be included
in the fibrous structures include permanent and/or temporary wet
strength resins, dry strength resins, softening agents, wetting
agents, lint resisting agents, absorbency-enhancing agents,
immobilizing agents, especially in combination with emollient
lotion compositions, antiviral agents including organic acids,
antibacterial agents, polyol polyesters, antimigration agents,
polyhydroxy plasticizers, opacifying agents and mixtures thereof.
Such ingredients, when present in the fibrous structure of the
present invention, may be present at any level based on the dry
weight of the fibrous structure. Typically, such ingredients, when
present, may be present at a level of from about 0.001 to about 50%
and/or from about 0.001 to about 20% and/or from about 0.01 to
about 5% and/or from about 0.03 to about 3% and/or from about 0.1
to about 1.0% by weight, on a dry fibrous structure basis.
[0044] The fibrous structures of the present invention may be of
any type, including but not limited to, conventionally felt-pressed
fibrous structures; pattern densified fibrous structures; and
high-bulk, uncompacted fibrous structures. The fibrous structures
may be creped or uncreped and/or through-dried or conventionally
dried. The sanitary tissue products made therefrom may be of a
single-ply or multi-ply construction.
[0045] The fibrous structures of the present invention and/or
sanitary tissue products comprising such fibrous structures may
have a basis weight of between about 10 g/m.sup.2 to about 120
g/m.sup.2 and/or from about 14 g/m.sup.2 to about 80 g/m.sup.2
and/or from about 20 g/m.sup.2 to about 60 g/m.sup.2.
[0046] The fibrous structures of the present invention and/or
sanitary tissue products comprising such fibrous structures may
have a total dry tensile strength of greater than about 59 g/cm
(150 g/in) and/or from about 78 g/cm (200 g/in) to about 394 g/cm
(1000 g/in) and/or from about 98 g/cm (250 g/in) to about 335 g/cm
(850 g/in).
[0047] The fibrous structures of the present invention and/or
sanitary tissue products comprising such fibrous structures may
have a density of about 0.60 g/cc or less and/or about 0.30 g/cc or
less and/or from about 0.04 g/cc to about 0.20 g/cc.
[0048] As shown in FIG. 2, a fibrous structure 20 comprises a
multifilament fiber 10 comprised of two or more monofilaments 12.
The fibrous structure 20 also comprises one or more monofilaments
12 which are not associated with other monofilaments 12 to form a
multifilament 10.
[0049] In one example, a multifilament fiber 10 can be used within
a fibrous structure 20 to convey to a consumer of the fibrous
structure 20 and/or sanitary tissue product comprising such fibrous
structure 20 that the fibrous structure 20 exhibits a certain
property or characteristic. In other words, the multifilament fiber
10 may function as a visual cue to inform a consumer that the
fibrous structure contains or does not contain a particular
ingredient (other than the fact that a multifilament fiber is
present) and/or that the fibrous structure exhibits a certain
property/characteristic such as softness.
[0050] In another example, a fibrous structure may comprise a fiber
that provides a visual cue that is associated with the presence of
a certain ingredient (other than the fact that a certain fiber is
present) and/or characteristic (i.e., certain property) is
provided. The fiber may be noticeable to a consumer of the fibrous
structure by being colored, of a different size, of a different
shape, of a different length, different texture from other fibers
within the fibrous structure.
[0051] In one example, the fibrous structure of the present
invention is a nonwoven fibrous structure.
Method for Making a Fibrous Structure
[0052] A fibrous structure comprising a multifilament fiber may be
made by any suitable method known in the art. In one example, a
method for making a fibrous structure comprising a multifilament
fiber comprises the step of forming a fibrous slurry and/or fibrous
composition comprising a multifilament fiber and depositing the
fibrous slurry and/or fibrous composition onto a forming belt such
that a fibrous structure is formed.
NONLIMITING EXAMPLES
Example 1
[0053] This Example illustrates a process for making a multi-ply
sanitary tissue product (i.e., a bathroom tissue) according to the
present invention using a through-air dried process.
[0054] An aqueous slurry of Northern Softwood Kraft (NSK) of about
3% consistency is made up using a conventional pulper and is passed
through a stock pipe toward the headbox of the Fourdrinier. A
dispersion of Parez 750C (available from Kemira Corporation of
Kennesaw, Ga.) wet strength resin about 1% in concentration is
mixed with this stock in an amount sufficient to deliver a total of
about 3 lb of resin per ton of finished paper product. Distribution
of the Parez 750C is aided by an in-line mixer. This wet strength
resin treated stock is diluted at the inlet of a first fan-pump
with recycled white water to a consistency of about 0.2%.
[0055] An aqueous slurry of acacia fibers (from Riau
Andalan--Indonesia) of about 3% by weight is made up using a
conventional repulper. After the acacia fibers are added to the
pulper, green cotton thread (spun cotton of 2 ply of 120.times.120
denier) cut to a length of 1/4'' is added to the pulper in an
amount to equal to about 1% of the final sheet weight. The pulping
intensity is controlled to fibrillate the multifilament threads at
the ends, but leaving the majority of the filament shaft intact.
The frayed ends will add to the attractiveness of the finished
product as well as improve the anchoring of the multifilaments in
the structure. The acacia & cotton thread slurry passes to the
second fan pump where it is diluted with white water to a
consistency of about 0.2%.
[0056] The slurries of NSK and acacia/thread are directed into a
multi-channeled headbox suitably equipped with layering leaves to
maintain the streams as separate layers until discharged onto a
traveling Fourdrinier wire. A three-chambered headbox is used. The
acacia/thread slurry containing 70% of the dry weight of the
ultimate paper is directed to the chambers leading to the two outer
layers while the NSK slurry comprising 30% of the dry weight of the
ultimate paper is directed to the chamber leading to the center
layer. The NSK and acacia/thread slurries are combined at the
discharge of the headbox into a composite slurry.
[0057] The composite slurry is discharged onto the traveling
Fourdrinier wire and is dewatered assisted by a deflector and
vacuum boxes. The embryonic wet web is transferred from the
Fourdrinier wire, at a fiber consistency of about 17% by weight at
the point of transfer, to a patterned drying fabric. The drying
fabric is designed to yield a pattern-densified tissue with
discontinuous low-density deflected areas arranged within a
continuous network of high density (knuckle) areas. This drying
fabric is formed by casting an impervious resin surface onto a
fiber mesh supporting fabric. The supporting fabric is a
48.times.52 filament, dual layer mesh. The thickness of the resin
cast is about 12 mil above the supporting fabric. The knuckle area
is about 40% and the open cells remain at a frequency of about 400
per square inch. The open cells are generally elliptical in shape
with the longer direction disposed in the machine direction and
having an aspect ratio of 0.866.
[0058] Further de-watering is accomplished by vacuum assisted
drainage until the web has a fiber consistency of about 22% by
weight. While remaining in contact with the patterned forming
fabric, the patterned web is pre-dried by air blow-through
pre-dryer to a fiber consistency of about 58% by weight.
[0059] The semi-dry web is then adhered to the surface of a Yankee
dryer with a sprayed creping adhesive comprising a 0.250% aqueous
solution of polyvinyl alcohol. The creping adhesive is delivered to
the Yankee surface at a rate of 0.1% adhesive solids based on the
dry weight of the web.
[0060] The fiber consistency is increased to about 98% before the
is dry creped from the Yankee with a doctor blade. The doctor blade
has a bevel angle of about 20.degree. and is positioned with
respect to the Yankee dryer to provide an impact angle of about
76.degree.. The Yankee dryer is operated at a temperature of about
350.degree. F. (177.degree. C.) and a speed of about 800 fpm (feet
per minute) (about 244 meters per minute). The paper is wound in a
roll using a surface driven reel drum having a surface speed of
about 680 fpm (about 207 meters per minute), thus resulting in a
crepe of about 15%.
[0061] After the doctor blade, the web is calendered across all its
width with a steel to rubber calendar roll to achieve the caliper
desired in the product. Resulting fibrous structure has a basis
weight of about 20 g/m2; a 1-ply total dry tensile between 250 and
about 300 g/in, a 1-ply initial total wet tensile between about 30
and about 35 g/in and a 1-ply caliper of about 0.018 inches.
Resulting fibrous structure is then plied together with a like
sheet to form a two-ply, creped, pattern densified fibrous
structure so that the Yankee-contacting surface, which is the
flatter surface, of each ply faces inward while the non-Yankee
contacting surface face outward. The plies are minimally tacked
together using about 1/2'' wide stripe of hot melt adhesive to
prevent the plies from easily separating. The resulting two-ply
fibrous structure has a) a total basis weight of about 40 g/m2 and
a caliper of about 0.028 inches.
[0062] The cotton threads provide an attractive and prominent
visual signal to consumers that a certain ingredient (not merely
that a cotton thread is present) and/or a certain property is
present in the fibrous structure.
Example 2
[0063] Example 1 is repeated except that the chopped cotton thread
is replaced with denim pulp. The denim pulp is made from recovered
scraps from the manufacture of clothing articles such as jeans
using denim fabric. It is processed by an entirely mechanical
process using a refiner until the fibers are chopped to
satisfactory papermaking lengths. Some of the denim filaments
retain their multifilament character. The denim pulp is added to
the pulper with the acacia fibers. Otherwise the practice of
Example 1 is repeated. The denim pulp multifilaments provide an
attractive and prominent visual signal to consumers that a certain
ingredient (not merely that a denim pulp multifilament is present)
and/or a certain property is present in the fibrous structure.
Example 3
[0064] Example 1 is repeated except that the chopped cotton thread
is replaced with green dyed polyester tow. The tow is 200 ends of 2
dpf polyester chopped to. Some of the tow bundles their
multifilament character. The denim pulp is added to the pulper with
the acacia fibers and the time and intensity of the pulping is
moderated so that most of the tow bundles retain a multifilament
character. The ends of the chopped tow segments tend to feather
outward creating a sheave appearance. This adds to their appearance
in the finished product as well as helping to anchor the tow in the
fibrous structure. Otherwise the practice of Example 1 is repeated.
The polyester tow multifilaments provide an attractive and
prominent visual signal to consumers that a certain ingredient (not
merely that a polyester tow multifilament is present) and/or a
certain property is present in the fibrous structure.
[0065] All documents cited in the Detailed Description of the
Invention 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. To the
extent that any meaning or definition of a term in this written
document conflicts with any meaning or definition of the term in a
document incorporated by reference, the meaning or definition
assigned to the term in this written document shall govern.
[0066] 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".
[0067] 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.
* * * * *