U.S. patent application number 12/040662 was filed with the patent office on 2009-09-03 for embossed fibrous structures.
Invention is credited to Douglas Jay Barkey, Charles Chidozie Ekenga, Thorsten Knobloch, John Allen Manifold, Kathleen Diane Sands.
Application Number | 20090220741 12/040662 |
Document ID | / |
Family ID | 40806723 |
Filed Date | 2009-09-03 |
United States Patent
Application |
20090220741 |
Kind Code |
A1 |
Manifold; John Allen ; et
al. |
September 3, 2009 |
EMBOSSED FIBROUS STRUCTURES
Abstract
Embossed fibrous structures that exhibit a Geometric Mean
Flexural Rigidity (GM Rigidity) of less than 7.48 cm as measured
according to the Flexural Rigidity Test and/or a Cross-Machine
Direction Flexural Rigidity (CD Flexural Rigidity) of less than as
measured according to the Flexural Rigidity Test Method are
provided.
Inventors: |
Manifold; John Allen;
(Milan, IN) ; Ekenga; Charles Chidozie;
(Cincinnati, OH) ; Barkey; Douglas Jay; (Hamilton
Township, OH) ; Sands; Kathleen Diane; (West Chester,
OH) ; Knobloch; Thorsten; (Loveland, OH) |
Correspondence
Address: |
THE PROCTER & GAMBLE COMPANY;Global Legal Department - IP
Sycamore Building - 4th Floor, 299 East Sixth Street
CINCINNATI
OH
45202
US
|
Family ID: |
40806723 |
Appl. No.: |
12/040662 |
Filed: |
February 29, 2008 |
Current U.S.
Class: |
428/141 |
Current CPC
Class: |
Y10T 428/24355 20150115;
D21H 27/005 20130101 |
Class at
Publication: |
428/141 |
International
Class: |
D06N 7/04 20060101
D06N007/04 |
Claims
1. An embossed fibrous structure that exhibits a GM Flexural
Rigidity of less than 7.48 cm as measured according to the Flexural
Rigidity Test Method and a Dry Burst of from greater than 225 g as
measured according to the Dry Burst Test Method.
2. The embossed fibrous structure according to claim 1 wherein the
embossed fibrous structure exhibits a GM Flexural Rigidity of less
than about 7 cm as measured according to the Flexural Rigidity Test
Method.
3. The embossed fibrous structure according to claim 1 wherein the
embossed fibrous structure exhibits a Dry Burst of than about 250 g
as measured according to the Dry Burst Test Method.
4. The embossed fibrous structure according to claim 1 wherein the
embossed fibrous structure comprises cellulosic pulp fibers.
5. The embossed fibrous structure according to claim 1 wherein the
embossed fibrous structure is a throughdried embossed fibrous
structure.
6. The embossed fibrous structure according to claim 1 wherein the
embossed fibrous structure is an uncreped embossed fibrous
structure.
7. The embossed fibrous structure according to claim 1 wherein the
embossed fibrous structure exhibits a basis weight of greater than
15 gsm to about 120 gsm as measured according to the Basis Weight
Test Method.
8. The embossed fibrous structure according to claim 1 wherein the
embossed fibrous structure is a sanitary tissue product.
9. The embossed fibrous structure according to claim 8 wherein the
sanitary tissue product is in roll form.
10. The embossed fibrous structure according to claim 8 wherein the
sanitary tissue product is a multi-ply sanitary tissue product.
11. An embossed fibrous structure that exhibits a CD Flexural
Rigidity of less than 7.75 cm as measured according to the Flexural
Rigidity Test Method and a Dry Burst of greater than 225 g as
measured according to the Dry Burst Test Method.
12. The embossed fibrous structure according to claim 11 wherein
the embossed fibrous structure exhibits a CD Flexural Rigidity of
less than 7.5 cm as measured according to the Flexural Rigidity
Test Method.
13. The embossed fibrous structure according to claim 11 wherein
the embossed fibrous structure exhibits a CD Flexural Rigidity of
greater than about 250 g as measured according to the Dry Burst
Test Method.
14. The embossed fibrous structure according to claim 11 wherein
the embossed fibrous structure comprises cellulosic pulp
fibers.
15. The embossed fibrous structure according to claim 11 wherein
the fibrous structure is a throughdried embossed fibrous
structure.
16. The embossed fibrous structure according to claim 11 wherein
the embossed fibrous structure is an uncreped embossed fibrous
structure.
17. The embossed fibrous structure according to claim 11 wherein
the embossed fibrous structure exhibits a basis weight of greater
than 15 gsm to about 120 gsm as measured according to the Basis
Weight Test Method.
18. The embossed fibrous structure according to claim 11 wherein
the embossed fibrous structure is a sanitary tissue product.
19. The embossed fibrous structure according to claim 18 wherein
the sanitary tissue product is in roll form.
20. The embossed fibrous structure according to claim 18 wherein
the sanitary tissue product is a multi-ply sanitary tissue product.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to embossed fibrous structures
that exhibit a Geometric Mean Flexural Rigidity (GM Flexural
Rigidity) of less than 7.48 cm as measured according to the
Flexural Rigidity Test Method and/or a Cross-Machine Direction
Flexural Rigidity (CD Flexural Rigidity) of less than 7.75 cm as
measured according to the Flexural Rigidity Test Method.
BACKGROUND OF THE INVENTION
[0002] Fibrous structures, particularly sanitary tissue products
comprising fibrous structures, are known to exhibit different
values for particular properties. These differences may translate
into one fibrous structure being softer or stronger or more
absorbent or more flexible or less flexible or exhibit greater
stretch or exhibit less stretch, for example, as compared to
another fibrous structure.
[0003] One property of fibrous structures that is desirable to
consumers is the Flexural Rigidity of the fibrous structure. It has
been found that at least some consumers desire embossed fibrous
structures that exhibit a GM Flexural Rigidity of less than 7.48
and/or a CD Flexural Rigidity of less than 7.75 cm as measured
according to the Flexural Rigidity Test Method.
SUMMARY OF THE INVENTION
[0004] The present invention fulfills the needs described above by
providing an embossed fibrous structure that exhibits a GM Flexural
Rigidity of less than 7.48 cm and/or a CD Flexural Rigidity of less
than 7.75 cm as measured according to the Flexural Rigidity Test
Method.
[0005] In one example of the present invention, an embossed fibrous
structure that exhibits a GM Flexural Rigidity of less than 7.48 cm
and a Dry Burst of greater than 225 g as measured according to the
Dry Burst Test Method is provided.
[0006] In another example of the present invention, an embossed
fibrous structure that exhibits a CD Flexural Rigidity of less than
7.75 cm as measured according to the Flexural Rigidity Test Method
and a Dry Burst of greater than 225 g as measured according to the
Dry Burst Test Method is provided.
[0007] Accordingly, the present invention provides embossed fibrous
structures that exhibit a GM Flexural Rigidity of less than 7.48 cm
as measured according to the Flexural Rigidity Test Method and/or a
CD Flexural Rigidity of less than 7.75 cm as measured according to
the Flexural Rigidity Test Method.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a plot of GM Flexural Rigidity to Dry Burst for
embossed fibrous structures of the present invention and
commercially available fibrous structures, both single-ply and
multi-ply, embossed and unembossed sanitary tissue products,
illustrating the relatively low level of GM Flexural Rigidity
exhibited by the embossed fibrous structures of the present
invention;
[0009] FIG. 2 is a plot of CD Flexural Rigidity to Dry Burst for
embossed fibrous structures of the present invention and
commercially available fibrous structures, both single-ply and
multi-ply sanitary tissue products, illustrating the relatively low
level of CD Flexural Rigidity exhibited by the embossed fibrous
structures of the present invention;
[0010] FIG. 3 is a schematic representation of an example of a
fibrous structure in accordance with the present invention;
[0011] FIG. 4 is a cross-sectional view of FIG. 3 taken along line
4-4;
[0012] FIG. 5 is a schematic representation of a prior art fibrous
structure comprising linear elements.
[0013] FIG. 6 is an electromicrograph of a portion of a prior art
fibrous structure;
[0014] FIG. 7 is a schematic representation of an example of a
fibrous structure according to the present invention;
[0015] FIG. 8 is a cross-section view of FIG. 7 taken along line
8-8;
[0016] FIG. 9 is a schematic representation of an example of a
fibrous structure according to the present invention;
[0017] FIG. 10 is a schematic representation of an example of a
fibrous structure according to the present invention;
[0018] FIG. 11 is a schematic representation of an example of a
fibrous structure according to the present invention;
[0019] FIG. 12 is a schematic representation of an example of a
fibrous structure comprising various forms of linear elements in
accordance with the present invention;
[0020] FIG. 13 is a schematic representation of an example of a
method for making a fibrous structure according to the present
invention;
[0021] FIG. 14 is a schematic representation a portion of an
example of a molding member in according with the present
invention;
[0022] FIG. 15 is a cross-section view of FIG. 14 taken along line
15-15.
DETAILED DESCRIPTION OF THE INVENTION
Definitions
[0023] "Fibrous structure" as used herein means a structure that
comprises one or more filaments and/or fibers. In one example, a
fibrous structure according to the present invention means an
orderly arrangement of filaments and/or fibers within a structure
in order to perform a function. Nonlimiting examples of fibrous
structures of the present invention include paper, fabrics
(including woven, knitted, and non-woven), and absorbent pads (for
example for diapers or feminine hygiene products).
[0024] Nonlimiting examples of processes for making 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 slurry 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.
[0025] 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.
[0026] The fibrous structures of the present invention may be
co-formed fibrous structures.
[0027] "Co-formed fibrous structure" as used herein means that the
fibrous structure comprises a mixture of at least two different
materials wherein at least one of the materials comprises a
filament, such as a polypropylene filament, and at least one other
material, different from the first material, comprises a solid
additive, such as a fiber and/or a particulate. In one example, a
co-formed fibrous structure comprises solid additives, such as
fibers, such as wood pulp fibers, and filaments, such as
polypropylene filaments.
[0028] "Solid additive" as used herein means a fiber and/or a
particulate.
[0029] "Particulate" as used herein means a granular substance or
powder.
[0030] "Fiber" and/or "Filament" 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. In one example, a "fiber" is an elongate particulate as
described above that exhibits a length of less than 5.08 cm (2 in.)
and a "filament" is an elongate particulate as described above that
exhibits a length of greater than or equal to 5.08 cm (2 in.).
[0031] Fibers are typically considered discontinuous in nature.
Nonlimiting examples of fibers include wood pulp fibers and
synthetic staple fibers such as polyester fibers.
[0032] Filaments are typically considered continuous or
substantially continuous in nature. Filaments are relatively longer
than fibers. Nonlimiting examples of filaments include meltblown
and/or spunbond filaments. Nonlimiting examples of materials that
can be spun into filaments include natural polymers, such as
starch, starch derivatives, cellulose and cellulose derivatives,
hemicellulose, hemicellulose derivatives, and synthetic polymers
including, but not limited to polyvinyl alcohol filaments and/or
polyvinyl alcohol derivative filaments, and thermoplastic polymer
filaments, such as polyesters, nylons, polyolefins such as
polypropylene filaments, polyethylene filaments, and biodegradable
or compostable thermoplastic fibers such as polylactic acid
filaments, polyhydroxyalkanoate filaments and polycaprolactone
filaments. The filaments may be monocomponent or multicomponent,
such as bicomponent filaments.
[0033] In one example of the present invention, "fiber" refers to
papermaking fibers. 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.
[0034] In addition to the various wood pulp fibers, other
cellulosic fibers such as cotton linters, rayon, lyocell and
bagasse can be used in this invention. Other sources of cellulose
in the form of fibers or capable of being spun into fibers include
grasses and grain sources.
[0035] "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 sanitary tissue product
roll.
[0036] In one example, the sanitary tissue product of the present
invention comprises a fibrous structure according to the present
invention.
[0037] The sanitary tissue products and/or fibrous structures of
the present invention may exhibit a basis weight of greater than 15
g/m2(9.2 lbs/3000 ft2) to about 120 g/m.sup.2 (73.8 lbs/3000 ft2)
and/or from about 15 g/m.sup.2 (9.2 lbs/3000 ft.sup.2) to about 110
g/m.sup.2 (67.7 lbs/300 ft .sup.2) and/or from about 20 g/m.sup.2
(12.3 lbs/3000 ft.sup.2) to about 100 g/m.sup.2 (61.5 lbs/3000
ft.sup.2) and/or from about 30 (18.5 lbs/3000 ft.sup.2) to 90
g/m.sup.2 (55.4 lbs/3000 ft.sup.2). In addition, the sanitary
tissue products and/or fibrous structures of the present invention
may exhibit a basis weight between about 40 g/m2 (24.6 lbs/3000
ft.sup.2) to about 120 g/m.sup.2 (73.8 lbs/3000 ft.sup.2) and/or
from about 50 g/m.sup.2 (30.8 lbs/3000 ft.sup.2) to about 110 g/m2
(67.7 lbs/3000 ft.sup.2) and/or from about 55 g/m.sup.2 (33.8
lbs/3000 ft2) to about 105 g/m (64.6 lbs/3000 ft.sup.2) and/or from
about 60 (36.9 lbs/3000 ft2) to 100 g/m.sup.2 (61.5 lbs/3000
ft.sup.2).
[0038] The sanitary tissue products of the present invention may
exhibit 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). In addition, the sanitary tissue product of the present
invention may exhibit a total dry tensile strength of greater than
about 196 g/cm (500 g/in) and/or from about 196 g/cm (500 g/in) to
about 394 g/cm (1000 g/in) and/or from about 216 g/cm (550 g/in) to
about 335 g/cm (850 g/in) and/or from about 236 g/cm (600 g/in) to
about 315 g/cm (800 g/in). In one example, the sanitary tissue
product exhibits a total dry tensile strength of less than about
394 g/cm (1000 g/in) and/or less than about 335 g/cm (850
g/in).
[0039] In another example, the sanitary tissue products of the
present invention may exhibit a total dry tensile strength of
greater than about 196 g/cm (500 g/in) and/or greater than about
236 g/cm (600 g/in) and/or greater than about 276 g/cm (700 g/in)
and/or greater than about 315 g/cm (800 g/in) and/or greater than
about 354 g/cm (900 g/in) and/or greater than about 394 g/cm (1000
g/in) and/or from about 315 g/cm (800 g/in) to about 1968 g/cm
(5000 g/in) and/or from about 354 g/cm (900 g/in) to about 1181
g/cm (3000 g/in) and/or from about 354 g/cm (900 g/in) to about 984
g/cm (2500 g/in) and/or from about 394 g/cm (1000 g/in) to about
787 g/cm (2000 g/in).
[0040] The sanitary tissue products of the present invention may
exhibit an initial total wet tensile strength of less than about 78
g/cm (200 g/in) and/or less than about 59 g/cm (150 g/in) and/or
less than about 39 g/cm (100 g/in) and/or less than about 29 g/cm
(75 g/in).
[0041] The sanitary tissue products of the present invention may
exhibit an initial total wet tensile strength of greater than about
118 g/cm (300 g/in) and/or greater than about 157 g/cm (400 g/in)
and/or greater than about 196 g/cm (500 g/in) and/or greater than
about 236 g/cm (600 g/in) and/or greater than about 276 g/cm (700
g/in) and/or greater than about 315 g/cm (800 g/in) and/or greater
than about 354 g/cm (900 g/in) and/or greater than about 394 g/cm
(1000 g/in) and/or from about 118 g/cm (300 g/in) to about 1968
g/cm (5000 g/in) and/or from about 157 g/cm (400 g/in) to about
1181 g/cm (3000 g/in) and/or from about 196 g/cm (500 g/in) to
about 984 g/cm (2500 g/in) and/or from about 196 g/cm (500 g/in) to
about 787 g/cm (2000 g/in) and/or from about 196 g/cm (500 g/in) to
about 591 g/cm (1500 g/in).
[0042] The sanitary tissue products of the present invention may
exhibit a density (measured at 95 g/in.sup.2) of less than about
0.60 g/cm.sup.3 and/or less than about 0.30 g/cm.sup.3 and/or less
than about 0.20 g/cm.sup.3 and/or less than about 0.10 g/cm.sup.3
and/or less than about 0.07 g/cm.sup.3 and/or less than about 0.05
g/cm.sup.3 and/or from about 0.01 g/cm.sup.3 to about 0.20
g/cm.sup.3 and/or from about 0.02 g/cm.sup.3 to about 0.10
g/cm.sup.3.
[0043] The sanitary tissue products of the present invention may
exhibit a total absorptive capacity of according to the Horizontal
Full Sheet (HFS) Test Method described herein of greater than about
10 g/g and/or greater than about 12 g/g and/or greater than about
15 g/g and/or from about 15 g/g to about 50 g/g and/or to about 40
g/g and/or to about 30 g/g.
[0044] The sanitary tissue products of the present invention may
exhibit a Vertical Full Sheet (VFS) value as determined by the
Vertical Full Sheet (VFS) Test Method described herein of greater
than about 5 g/g and/or greater than about 7 g/g and/or greater
than about 9 g/g and/or from about 9 g/g to about 30 g/g and/or to
about 25 g/g and/or to about 20 g/g and/or to about 17 g/g.
[0045] The sanitary tissue products of the present invention may be
in the form of sanitary tissue product rolls. Such sanitary tissue
product rolls may comprise a plurality of connected, but perforated
sheets of fibrous structure, that are separably dispensable from
adjacent sheets.
[0046] The sanitary tissue products of the present invention may
comprises additives such as softening agents, temporary wet
strength agents, permanent wet strength agents, bulk softening
agents, lotions, silicones, wetting agents, latexes, especially
surface-pattern-applied latexes, dry strength agents such as
carboxymethylcellulose and starch, and other types of additives
suitable for inclusion in and/or on sanitary tissue products.
[0047] "Weight average molecular weight" as used herein means the
weight average molecular weight as determined using gel permeation
chromatography according to the protocol found in Colloids and
Surfaces A. Physico Chemical & Engineering Aspects, Vol. 162,
2000, pg. 107-121.
[0048] "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 and is measured
according to the Basis Weight Test Method described herein.
[0049] "Caliper" as used herein means the macroscopic thickness of
a fibrous structure. Caliper is measured according to the Caliper
Test Method described herein.
[0050] "Bulk" as used herein is calculated as the quotient of the
Caliper (hereinafter defined), expressed in microns, divided by the
basis weight, expressed in grams per square meter. The resulting
Bulk is expressed as cubic centimeters per gram. For the products
of this invention, Bulks can be greater than about 3 cm.sup.3/g
and/or greater than about 6 cm.sup.3/g and/or greater than about 9
cm.sup.3/g and/or greater than about 10.5 cm.sup.3/g up to about 30
cm.sup.3/g and/or up to about 20 cm.sup.3/g. The products of this
invention derive the Bulks referred to above from the basesheet,
which is the sheet produced by the tissue machine without post
treatments such as embossing. Nevertheless, the basesheets of this
invention can be embossed to produce even greater bulk or
aesthetics, if desired, or they can remain unembossed. In addition,
the basesheets of this invention can be calendered to improve
smoothness or decrease the Bulk if desired or necessary to meet
existing product specifications.
[0051] "Basis Weight Ratio" as used herein is the ratio of low
basis weight portion of a fibrous structure to a high basis weight
portion of a fibrous structure. In one example, the fibrous
structures of the present invention exhibit a basis weight ratio of
from about 0.02 to about 1. In another example, the basis weight
ratio of the basis weight of a linear element of a fibrous
structure to another portion of a fibrous structure of the present
invention is from about 0.02 to about 1.
[0052] "Geometric Mean ("GM") Elongation" as used herein is
determined as described in the Elongation Test Method described
herein.
[0053] "Dry Burst" as used herein is determined as described in the
Dry Burst Test Method described herein.
[0054] "Geometric Mean ("GM") Modulus" as used herein is determined
as described in the Modulus Test Method described herein.
[0055] "Machine Direction" or "MD" as used herein means the
direction parallel to the flow of the fibrous structure through the
fibrous structure making machine and/or sanitary tissue product
manufacturing equipment.
[0056] "Cross Machine Direction" or "CD" as used herein means the
direction parallel to the width of the fibrous structure making
machine and/or sanitary tissue product manufacturing equipment and
perpendicular to the machine direction.
[0057] "Ply" as used herein means an individual, integral fibrous
structure.
[0058] "Plies" as used herein means two or more individual,
integral fibrous structures disposed in a substantially contiguous,
face-to-face relationship with one another, forming a multi-ply
fibrous structure and/or multi-ply sanitary tissue product. It is
also contemplated that an individual, integral fibrous structure
can effectively form a multi-ply fibrous structure, for example, by
being folded on itself.
[0059] "Linear element" as used herein means a discrete,
unidirectional, uninterrupted portion of a fibrous structure having
length of greater than about 4.5 mm. In one example, a linear
element may comprise a plurality of non-linear elements. In one
example, a linear element in accordance with the present invention
is water-resistant. Unless otherwise stated, the linear elements of
the present invention are present on a surface of a fibrous
structure. The length and/or width and/or height of the linear
element and/or linear element forming component within a molding
member, which results in a linear element within a fibrous
structure, is measured by the Dimensions of Linear Element/Linear
Element Forming Component Test Method described herein.
[0060] In one example, the linear element and/or linear element
forming component is continuous or substantially continuous with a
usable fibrous structure, for example in one case one or more 11
cm.times.11 cm sheets of fibrous structure.
[0061] "Discrete" as it refers to a linear element means that a
linear element has at least one immediate adjacent region of the
fibrous structure that is different from the linear element.
[0062] "Unidirectional" as it refers to a linear element means that
along the length of the linear element, the linear element does not
exhibit a directional vector that contradicts the linear element's
major directional vector.
[0063] "Uninterrupted" as it refers to a linear element means that
a linear element does not have a region that is different from the
linear element cutting across the linear element along its length.
Undulations within a linear element such as those resulting from
operations such creping and/or foreshortening are not considered to
result in regions that are different from the linear element and
thus do not interrupt the linear element along its length.
[0064] "Water-resistant" as it refers to a linear element means
that a linear element retains its structure and/or integrity after
being saturated.
[0065] "Substantially machine direction oriented" as it refers to a
linear element means that the total length of the linear element
that is positioned at an angle of greater than 45.degree. to the
cross machine direction is greater than the total length of the
linear element that is positioned at an angle of 45.degree. or less
to the cross machine direction.
[0066] "Substantially cross machine direction oriented" as it
refers to a linear element means that the total length of the
linear element that is positioned at an angle of 45.degree. or
greater to the machine direction is greater than the total length
of the linear element that is positioned at an angle of less than
45.degree. to the machine direction.
Fibrous Structure
[0067] The fibrous structures of the present invention may be a
single-ply or multi-ply fibrous structure.
[0068] In one example of the present invention as shown in FIG. 1,
a fibrous structure exhibits a GM Flexural Rigidity of less than
7.48 cm and/or less than about 7 cm and/or less than about 5.7 cm
and/or greater than about 3 cm and/or greater than about 4.5 cm as
measured according to the Flexural Rigidity Test Method.
[0069] In another example of the present invention as shown in FIG.
2, a fibrous structure exhibits a MD Modulus of greater than 1350
at 15 g/cm and/or greater than about 1355 at 15 g/cm and/or greater
than about 1357 at 15 g/cm and/or to less than about 7000 at 15
g/cm and/or to less than about 5000 at 15 g/cm and/or to less than
about 4000 at 15 g/cm and/or to less than about 3000 at 15 g/cm as
measured according to the Modulus Test Method.
[0070] In another example of the present invention as shown in FIG.
3, a fibrous structure exhibits a CD Flexural Rigidity of less than
7.75 cm and/or less than about 7.5 cm and/or less than about 7 cm
and/or to greater than about 0.5 cm and/or to greater than about 1
cm and/or to greater than about 3 cm as measured according to the
Flexural Rigidity Test Method.
[0071] In another example of the present invention as shown in FIG.
3, a fibrous structure, for examples a single-ply fibrous
structure, exhibits a Dry Burst of greater than 360 g and/or
greater than about 370 g and/or greater than about 400 g and/or
greater than about 425 g and/or to less than 605 g and/or to less
than about 575 g and/or to less than about 550 g and/or to less
than about 500 g as measured according to the Dry Burst Test
Method. In another example of the present invention as shown in
FIG. 3, a fibrous structure, such as a multi-ply fibrous structure,
exhibits a Dry Burst of greater than 360 g and/or greater than
about 370 g and/or greater than about 400 g and/or greater than
about 425 g and/or to less than about 2000 g and/or to less than
about 1500 g and/or to less than about 1000 g and/or to less than
about 800 g and/or to less than about 740 g and/or to less than
about 605 g and/or to less than about 575 g and/or to less than
about 550 g/and/or to less than about 500 g as measured according
to the Dry Burst Test Method.
[0072] Table 1 below shows the physical property values of some
fibrous structures in accordance with the present invention and
commercially available fibrous structures.
TABLE-US-00001 GM CD Flexural Flexural MD Dry Basis # of Rigidity
Rigidity Modulus Burst Weight Fibrous Structure Plies Embossed cm
cm 15 g/cm g gsm Invention 2 Y 6.7 6.4 1187 399 38.3 Invention 2 Y
5.6 5.1 1357 439 39.1 Charmin .RTM. Basic 1 N 3.8 4.4 583 215 29.4
Charmin .RTM. Basic 1 N 3.7 4.5 375 194 28.8 Charmin .RTM. Ultra
Strong 2 Y 7.5 7.8 1049 303 38.1 Cottonelle .RTM. Ultra 2 N 5.9 4.6
1205 357 44.5 Cottonelle .RTM. Ultra 2 N 5.9 4.6 1347 342 42.8
Cottonelle .RTM. with 1 N 4.8 3.6 1032 259 30.5 Ripples Bounty
.RTM. Basic 1 N 6.2 6.7 1116 606 43.7 Kleenex Viva .RTM. 1 N 5.1
5.4 554 663 65.5 Quilted Northern .RTM. 2 Y 5.4 5.8 571 149 45.7
Ultra Quilted Northern .RTM. 2 Y 5.2 5.4 775 218 37.5 Angel Soft
.RTM. 2 Y 4.4 4.5 1104 217 34.3
[0073] In another example of the present invention, a fibrous
structure exhibits a Dry Burst of greater than 225 g and/or greater
than 250 g and/or greater than 300 g and/or 360 g and/or greater
than about 395 g and/or greater than about 425 g and/or less than
about 2000 g and/or less than about 1500 g and/or less than about
1000 g and/or from about 360 g to about 1000 g and/or from about
395 g to about 600 g and/or from about 395 g to about 500 g as
measured according to the Dry Burst Test Method.
[0074] In even yet another example of the present invention, an
embossed fibrous structure comprises cellulosic pulp fibers.
However, other naturally-occurring and/or non-naturally occurring
fibers and/or filaments may be present in the fibrous structures of
the present invention.
[0075] In one example of the present invention, an embossed fibrous
structure comprises a throughdried fibrous structure. The embossed
fibrous structure may be creped or uncreped. In one example, the
embossed fibrous structure is a wet-laid fibrous structure.
[0076] In another example of the present invention, an embossed
fibrous structure may comprise one or more embossments.
[0077] The embossed fibrous structure may be incorporated into a
single- or multi-ply sanitary tissue product. The sanitary tissue
product may be in roll form where it is convolutedly wrapped about
itself with or without the employment of a core.
[0078] A nonlimiting example of a fibrous structure in accordance
with the present invention is shown in FIGS. 3 and 4. FIGS. 3 and 4
show a fibrous structure 10 comprising one or more linear elements
12. The linear elements 12 are oriented in the machine or
substantially the machine direction on the surface 14 of the
fibrous structure 10. In one example, one or more of the linear
elements 12 may exhibit a length L of greater than about 4.5 mm
and/or greater than about 6 mm and/or greater than about 10 mm
and/or greater than about 20 mm and/or greater than about 30 mm
and/or greater than about 45 mm and/or greater than about 60 mm
and/or greater than about 75 mm and/or greater than about 90 mm.
For comparison, as shown in FIG. 5, a schematic representation of a
commercially available toilet tissue product 20 has a plurality of
substantially machine direction oriented linear elements 12 wherein
the longest linear element 12 present in the toilet tissue product
20 exhibits a length L' of 4.3 mm or less. FIG. 6 is a micrograph
of a surface of a commercially available toilet tissue product 30
that comprises substantially machine direction oriented linear
elements 12 wherein the longest linear element 12 present in the
toilet tissue product 30 exhibits a length L'' of 4.3 mm or
less.
[0079] In one example, the width W of one or more of the linear
elements 12 is less than about 10 mm and/or less than about 7 mm
and/or less than about 5 mm and/or less than about 2 mm and/or less
than about 1.7 mm and/or less than about 1.5 mm to about 0 mm
and/or to about 0.10 mm and/or to about 0.20 mm. In another
example, the linear element height of one or more of the linear
elements is greater than about 0.10 mm and/or greater than about
0.50 mm and/or greater than about 0.75 mm and/or greater than about
1 mm to about 4 mm and/or to about 3 mm and/or to about 2.5 mm
and/or to about 2 mm.
[0080] In another example, the fibrous structure of the present
invention exhibits a ratio of linear element height (in mm) to
linear element width (in mm) of greater than about 0.35 and/or
greater than about 0.45 and/or greater than about 0.5 and/or
greater than about 0.75 and/or greater than about 1.
[0081] One or more of the linear elements may exhibit a geometric
mean of linear element height by linear element of width of greater
than about 0.25 mm.sup.2 and/or greater than about 0.35 mm.sup.2
and/or greater than about 0.5 mm.sup.2 and/or greater than about
0.75 mm.sup.2.
[0082] As shown in FIGS. 3 and 4, the fibrous structure 10 may
comprise a plurality of substantially machine direction oriented
linear elements 12 that are present on the fibrous structure 10 at
a frequency of greater than about 1 linear element/5 cm and/or
greater than about 4 linear elements/5 cm and/or greater than about
7 linear elements/5 cm and/or greater than about 15 linear
elements/5 cm and/or greater than about 20 linear elements/5 cm
and/or greater than about 25 linear elements/5 cm and/or greater
than about 30 linear elements/5 cm up to about 50 linear elements/5
cm and/or to about 40 linear elements/5 cm.
[0083] In another example of a fibrous structure according to the
present invention, the fibrous structure exhibits a ratio of a
frequency of linear elements (per cm) to the width (in cm) of one
linear element of greater than about 3 and/or greater than about 5
and/or greater than about 7.
[0084] The linear elements of the present invention may be in any
shape, such as lines, zig-zag lines, serpentine lines. In one
example, a linear element does not intersect another linear
element.
[0085] As shown in FIGS. 7 and 8, a fibrous structure 10' of the
present invention may comprise one or more linear elements 12'. The
linear elements 12' may be oriented on a surface 14' of a fibrous
structure 12' in any direction such as machine direction, cross
machine direction, substantially machine direction oriented,
substantially cross machine direction oriented. Two or more linear
elements may be oriented in different directions on the same
surface of a fibrous structure according to the present invention.
In the case of FIGS. 7 and 8, the linear elements 12' are oriented
in the cross machine direction. Even though the fibrous structure
10' comprises only two linear elements 12', it is within the scope
of the present invention for the fibrous structure 10' to comprise
three or more linear elements 12'.
[0086] The dimensions (length, width and/or height) of the linear
elements of the present invention may vary from linear element to
linear element within a fibrous structure. As a result, the gap
width between neighboring linear elements may vary from one gap to
another within a fibrous structure.
[0087] In one example, the linear element may comprise an
embossment. In another example, the linear element may be an
embossed linear element rather than a linear element formed during
a fibrous structure making process.
[0088] In another example, a plurality of linear elements may be
present on a surface of a fibrous structure in a pattern such as in
a corduroy pattern.
[0089] In still another example, a surface of a fibrous structure
may comprise a discontinuous pattern of a plurality of linear
elements wherein at least one of the linear elements exhibits a
linear element length of greater than about 30 mm.
[0090] In yet another example, a surface of a fibrous structure
comprises at least one linear element that exhibits a width of less
than about 10 mm and/or less than about 7 mm and/or less than about
5 mm and/or less than about 3 mm and/or to about 0.01 mm and/or to
about 0.1 mm and/or to about 0.5 mm.
[0091] The linear elements may exhibit any suitable height known to
those of skill in the art. For example, a linear element may
exhibit a height of greater than about 0.10 mm and/or greater than
about 0.20 mm and/or greater than about 0.30 mm to about 3.60 mm
and/or to about 2.75 mm and/or to about 1.50 mm. A linear element's
height is measured irrespective of arrangement of a fibrous
structure in a multi-ply fibrous structure, for example, the linear
element's height may extend inward within the fibrous
structure.
[0092] The fibrous structures of the present invention may comprise
at least one linear element that exhibits a height to width ratio
of greater than about 0.350 and/or greater than about 0.450 and/or
greater than about 0.500 and/or greater than about 0.600 and/or to
about 3 and/or to about 2 and/or to about 1.
[0093] In another example, a linear element on a surface of a
fibrous structure may exhibit a geometric mean of height by width
of greater than about 0.250 and/or greater than about 0.350 and/or
greater than about 0.450 and/or to about 3 and/or to about 2 and/or
to about 1.
[0094] The fibrous structures of the present invention may comprise
linear elements in any suitable frequency. For example, a surface
of a fibrous structure may comprises linear elements at a frequency
of greater than about 1 linear element/5 cm and/or greater than
about 1 linear element/3 cm and/or greater than about 1 linear
element/cm and/or greater than about 3 linear elements/cm.
[0095] In one example, a fibrous structure comprises a plurality of
linear elements that are present on a surface of the fibrous
structure at a ratio of frequency of linear elements to width of at
least one linear element of greater than about 3 and/or greater
than about 5 and/or greater than about 7.
[0096] The fibrous structure of the present invention may comprise
a surface comprising a plurality of linear elements such that the
ratio of geometric mean of height by width of at least one linear
element to frequency of linear elements is greater than about 0.050
and/or greater than about 0.750 and/or greater than about 0.900
and/or greater than about 1 and/or greater than about 2 and/or up
to about 20 and/or up to about 15 and/or up to about 10.
[0097] In addition to one or more linear elements 12'', as shown in
FIG. 9, a fibrous structure 10'' of the present invention may
further comprise one or more non-linear elements 16''. In one
example, a non-linear element 16'' present on the surface 14'' of a
fibrous structure 10'' is water-resistant. In another example, a
non-linear element 16'' present on the surface 14'' of a fibrous
structure 10'' comprises an embossment. When present on a surface
of a fibrous structure, a plurality of non-linear elements may be
present in a pattern. The pattern may comprise a geometric shape
such as a polygon. Nonlimiting example of suitable polygons are
selected from the group consisting of: triangles, diamonds,
trapezoids, parallelograms, rhombuses, stars, pentagons, hexagons,
octagons and mixtures thereof.
[0098] One or more of the fibrous structures of the present
invention may form a single- or multi-ply sanitary tissue product.
In one example, as shown in FIG. 10, a multi-ply sanitary tissue
product 30 comprises a first ply 32 and a second ply 34 wherein the
first ply 32 comprises a surface 14''' comprising a plurality of
linear elements 12''', in this case being oriented in the machine
direction or substantially machine direction oriented. The plies 32
and 34 are arranged such that the linear elements 12''' extend
inward into the interior of the sanitary tissue product 30 rather
than outward.
[0099] In another example, as shown in FIG. 11, a multi-ply
sanitary tissue product 40 comprises a first ply 42 and a second
ply 44 wherein the first ply 42 comprises a surface 14''''
comprising a plurality of linear elements 12'''', in this case
being oriented in the machine direction or substantially machine
direction oriented. The plies 42 and 44 are arranged such that the
linear elements 12'''' extend outward from the surface 14'''' of
the sanitary tissue product 40 rather than inward into the interior
of the sanitary tissue product 40.
[0100] As shown in FIG. 12, a fibrous structure 10''' of the
present invention may comprise a variety of different forms of
linear elements 12''''', alone or in combination, such as
serpentines, dashes, MD and/or CD oriented, and the like.
Methods for Making Fibrous Structures
[0101] The fibrous structures of the present invention may be made
by any suitable process known in the art. The method may be a
fibrous structure making process that uses a cylindrical dryer such
as a Yankee (a Yankee-process) or it may be a Yankeeless process as
is used to make substantially uniform density and/or uncreped
fibrous structures.
[0102] The fibrous structure of the present invention may be made
using a molding member. A "molding member" is a structural element
that can be used as a support for an embryonic web comprising a
plurality of cellulosic fibers and a plurality of synthetic fibers,
as well as a forming unit to form, or "mold," a desired
microscopical geometry of the fibrous structure of the present
invention. The molding member may comprise any element that has
fluid-permeable areas and the ability to impart a microscopical
three-dimensional pattern to the structure being produced thereon,
and includes, without limitation, single-layer and multi-layer
structures comprising a stationary plate, a belt, a woven fabric
(including Jacquard-type and the like woven patterns), a band, and
a roll. In one example, the molding member is a deflection
member.
[0103] A "reinforcing element" is a desirable (but not necessary)
element in some embodiments of the molding member, serving
primarily to provide or facilitate integrity, stability, and
durability of the molding member comprising, for example, a
resinous material. The reinforcing element can be fluid-permeable
or partially fluid-permeable, may have a variety of embodiments and
weave patterns, and may comprise a variety of materials, such as,
for example, a plurality of interwoven yarns (including
Jacquard-type and the like woven patterns), a felt, a plastic,
other suitable synthetic material, or any combination thereof.
[0104] In one example of a method for making a fibrous structure of
the present invention, the method comprises the step of contacting
an embryonic fibrous web with a deflection member (molding member)
such that at least one portion of the embryonic fibrous web is
deflected out-of-plane of another portion of the embryonic fibrous
web. The phrase "out-of-plane" as used herein means that the
fibrous structure comprises a protuberance, such as a dome, or a
cavity that extends away from the plane of the fibrous structure.
The molding member may comprise a through-air-drying fabric having
its filaments arranged to produce linear elements within the
fibrous structures of the present invention and/or the
through-air-drying fabric or equivalent may comprise a resinous
framework that defines deflection conduits that allow portions of
the fibrous structure to deflect into the conduits thus forming
linear elements within the fibrous structures of the present
invention. In addition, a forming wire, such as a foraminous member
may be arranged such that linear elements within the fibrous
structures of the present invention are formed and/or like the
through-air-drying fabric, the foraminous member may comprise a
resinous framework that defines deflection conduits that allow
portions of the fibrous structure to deflect into the conduits thus
forming linear elements within the fibrous structures of the
present invention.
[0105] In another example of a method for making a fibrous
structure of the present invention, the method comprises the steps
of:
[0106] (a) providing a fibrous furnish comprising fibers; and
[0107] (b) depositing the fibrous furnish onto a deflection member
such that at least one fiber is deflected out-of-plane of the other
fibers present on the deflection member.
[0108] In still another example of a method for making a fibrous
structure of the present invention, the method comprises the steps
of:
[0109] (a) providing a fibrous furnish comprising fibers;
[0110] (b) depositing the fibrous furnish onto a foraminous member
to form an embryonic fibrous web;
[0111] (c) associating the embryonic fibrous web with a deflection
member such that at least one fiber is deflected out-of-plane of
the other fibers present in the embryonic fibrous web; and
[0112] (d) drying said embryonic fibrous web such that that the
dried fibrous structure is formed.
[0113] In another example of a method for making a fibrous
structure of the present invention, the method comprises the steps
of:
[0114] (a) providing a fibrous furnish comprising fibers;
[0115] (b) depositing the fibrous furnish onto a first foraminous
member such that an embryonic fibrous web is formed;
[0116] (c) associating the embryonic web with a second foraminous
member which has one surface (the embryonic fibrous web-contacting
surface) comprising a macroscopically monoplanar network surface
which is continuous and patterned and which defines a first region
of deflection conduits and a second region of deflection conduits
within the first region of deflection conduits;
[0117] (d) deflecting the fibers in the embryonic fibrous web into
the deflection conduits and removing water from the embryonic web
through the deflection conduits so as to form an intermediate
fibrous web under such conditions that the deflection of fibers is
initiated no later than the time at which the water removal through
the deflection conduits is initiated; and
[0118] (e) optionally, drying the intermediate fibrous web; and
[0119] (f) optionally, foreshortening the intermediate fibrous
web.
[0120] The fibrous structures of the present invention may be made
by a method wherein a fibrous furnish is applied to a first
foraminous member to produce an embryonic fibrous web. The
embryonic fibrous web may then come into contact with a second
foraminous member that comprises a deflection member to produce an
intermediate fibrous web that comprises a network surface and at
least one dome region. The intermediate fibrous web may then be
further dried to form a fibrous structure of the present
invention.
[0121] FIG. 13 is a simplified, schematic representation of one
example of a continuous fibrous structure making process and
machine useful in the practice of the present invention.
[0122] As shown in FIG. 13, one example of a process and equipment,
represented as 50 for making a fibrous structure according to the
present invention comprises supplying an aqueous dispersion of
fibers (a fibrous furnish) to a headbox 52 which can be of any
convenient design. From headbox 52 the aqueous dispersion of fibers
is delivered to a first foraminous member 54 which is typically a
Fourdrinier wire, to produce an embryonic fibrous web 56.
[0123] The first foraminous member 54 may be supported by a breast
roll 58 and a plurality of return rolls 60 of which only two are
shown. The first foraminous member 54 can be propelled in the
direction indicated by directional arrow 62 by a drive means, not
shown. Optional auxiliary units and/or devices commonly associated
fibrous structure making machines and with the first foraminous
member 54, but not shown, include forming boards, hydrofoils,
vacuum boxes, tension rolls, support rolls, wire cleaning showers,
and the like.
[0124] After the aqueous dispersion of fibers is deposited onto the
first foraminous member 54, embryonic fibrous web 56 is formed,
typically by the removal of a portion of the aqueous dispersing
medium by techniques well known to those skilled in the art. Vacuum
boxes, forming boards, hydrofoils, and the like are useful in
effecting water removal. The embryonic fibrous web 56 may travel
with the first foraminous member 54 about return roll 60 and is
brought into contact with a deflection member 64, which may also be
referred to as a second foraminous member. While in contact with
the deflection member 64, the embryonic fibrous web 56 will be
deflected, rearranged, and/or further dewatered.
[0125] The deflection member 64 may be in the form of an endless
belt. In this simplified representation, deflection member 64
passes around and about deflection member return rolls 66 and
impression nip roll 68 and may travel in the direction indicated by
directional arrow 70. Associated with deflection member 64, but not
shown, may be various support rolls, other return rolls, cleaning
means, drive means, and the like well known to those skilled in the
art that may be commonly used in fibrous structure making
machines.
[0126] Regardless of the physical form which the deflection member
64 takes, whether it is an endless belt as just discussed or some
other embodiment such as a stationary plate for use in making
handsheets or a rotating drum for use with other types of
continuous processes, it must have certain physical
characteristics. For example, the deflection member may take a
variety of configurations such as belts, drums, flat plates, and
the like.
[0127] First, the deflection member 64 may be foraminous. That is
to say, it may possess continuous passages connecting its first
surface 72 (or "upper surface" or "working surface"; i.e. the
surface with which the embryonic fibrous web is associated,
sometimes referred to as the "embryonic fibrous web-contacting
surface") with its second surface 74 (or "lower surface"; i.e., the
surface with which the deflection member return rolls are
associated). In other words, the deflection member 64 may be
constructed in such a manner that when water is caused to be
removed from the embryonic fibrous web 56, as by the application of
differential fluid pressure, such as by a vacuum box 76, and when
the water is removed from the embryonic fibrous web 56 in the
direction of the deflection member 64, the water can be discharged
from the system without having to again contact the embryonic
fibrous web 56 in either the liquid or the vapor state.
[0128] Second, the first surface 72 of the deflection member 64 may
comprise one or more ridges 78 as represented in one example in
FIGS. 11 and 12. The ridges 78 may be made by any suitable
material. For example, a resin may be used to create the ridges 78.
The ridges 78 may be continuous, or essentially continuous. In one
example, the ridges 78 exhibit a length of greater than about 30
mm. The ridges 78 may be arranged to produce the fibrous structures
of the present invention when utilized in a suitable fibrous
structure making process. The ridges 78 may be patterned. The
ridges 78 may be present on the deflection member 64 at any
suitable frequency to produce the fibrous structures of the present
invention. The ridges 78 may define within the deflection member 64
a plurality of deflection conduits 80. The deflection conduits 80
may be discrete, isolated, deflection conduits.
[0129] The deflection conduits 80 of the deflection member 64 may
be of any size and shape or configuration so long at least one
produces a linear element in the fibrous stricture produced
thereby. The deflection conduits 80 may repeat in a random pattern
or in a uniform pattern. Portions of the deflection member 64 may
comprise deflection conduits 80 that repeat in a random pattern and
other portions of the deflection member 64 may comprise deflection
conduits 80 that repeat in a uniform pattern.
[0130] The ridges 78 of the deflection member 64 may be associated
with a belt, wire or other type of substrate. As shown in FIGS. 14
and 15, the ridges 78 of the deflection member 64 is associated
with a woven belt 82. The woven belt 82 may be made by any suitable
material, for example polyester, known to those skilled in the
art.
[0131] As shown in FIG. 15, a cross sectional view of a portion of
the deflection member 64 taken along line 15-15 of FIG. 14, the
deflection member 64 can be foraminous since the deflection
conduits 80 extend completely through the deflection member 64.
[0132] In one example, the deflection member of the present
invention may be an endless belt which can be constructed by, among
other methods, a method adapted from techniques used to make
stencil screens. By "adapted" it is meant that the broad, overall
techniques of making stencil screens are used, but improvements,
refinements, and modifications as discussed below are used to make
member having significantly greater thickness than the usual
stencil screen.
[0133] Broadly, a foraminous member (such as a woven belt) is
thoroughly coated with a liquid photosensitive polymeric resin to a
preselected thickness. A mask or negative incorporating the pattern
of the preselected ridges is juxtaposed the liquid photosensitive
resin; the resin is then exposed to light of an appropriate wave
length through the mask. This exposure to light causes curing of
the resin in the exposed areas. Unexpected (and uncured) resin is
removed from the system leaving behind the cured resin forming the
ridges defining within it a plurality of deflection conduits.
[0134] In another example, the deflection member can be prepared
using as the foraminous member, such as a woven belt, of width and
length suitable for use on the chosen fibrous structure making
machine. The ridges and the deflection conduits are formed on this
woven belt in a series of sections of convenient dimensions in a
batchwise manner, i.e. one section at a time. Details of this
nonlimiting example of a process for preparing the deflection
member follow.
[0135] First, a planar forming table is supplied. This forming
table is at least as wide as the width of the foraminous woven
element and is of any convenient length. It is provided with means
for securing a backing film smoothly and tightly to its surface.
Suitable means include provision for the application of vacuum
through the surface of the forming table, such as a plurality of
closely spaced orifices and tensioning means.
[0136] A relatively thin, flexible polymeric (such as
polypropylene) backing film is placed on the forming table and is
secured thereto, as by the application of vacuum or the use of
tension. The backing film serves to protect the surface of the
forming table and to provide a smooth surface from which the cured
photosensitive resins will, later, be readily released. This
backing film will form no part of the completed deflection
member.
[0137] Either the backing film is of a color which absorbs
activating light or the backing film is at least semi-transparent
and the surface of the forming table absorbs activating light.
[0138] A thin film of adhesive, such as 8091 Crown Spray Heavy Duty
Adhesive made by Crown Industrial Products Co. of Hebron, Ill., is
applied to the exposed surface of the backing film or,
alternatively, to the knuckles of the woven belt. A section of the
woven belt is then placed in contact with the backing film where it
is held in place by the adhesive. The woven belt is under tension
at the time it is adhered to the backing film.
[0139] Next, the woven belt is coated with liquid photosensitive
resin. As used herein, "coated" means that the liquid
photosensitive resin is applied to the woven belt where it is
carefully worked and manipulated to insure that all the openings
(interstices) in the woven belt are filled with resin and that all
of the filaments comprising the woven belt are enclosed with the
resin as completely as possible. Since the knuckles of the woven
belt are in contact with the backing film, it will not be possible
to completely encase the whole of each filament with photosensitive
resin. Sufficient additional liquid photosensitive resin is applied
to the woven belt to form a deflection member having a certain
preselected thickness. The deflection member can be from about 0.35
mm (0.014 in.) to about 3.0 mm (0.150 in.) in overall thickness and
the ridges can be spaced from about 0.10 mm (0.004 in.) to about
2.54 mm (0.100 in.) from the mean upper surface of the knuckles of
the woven belt. Any technique well known to those skilled in the
art can be used to control the thickness of the liquid
photosensitive resin coating. For example, shims of the appropriate
thickness can be provided on either side of the section of
deflection member under construction; an excess quantity of liquid
photosensitive resin can be applied to the woven belt between the
shims; a straight edge resting on the shims and can then be drawn
across the surface of the liquid photosensitive resin thereby
removing excess material and forming a coating of a uniform
thickness.
[0140] Suitable photosensitive resins can be readily selected from
the many available commercially. They are typically materials,
usually polymers, which cure or cross-link under the influence of
activating radiation, usually ultraviolet (UV) light. References
containing more information about liquid photosensitive resins
include Green et al, "Photocross-linkable Resin Systems," J. Macro.
Sci-Revs. Macro. Chem, C21(2), 187-273 (1981-82); Boyer, "A Review
of Ultraviolet Curing Technology," Tappi Paper Synthetics Conf.
Proc., Sep. 25-27, 1978, pp 167-172; and Schmidle, "Ultraviolet
Curable Flexible Coatings," J. of Coated Fabrics, 8, 10-20 (July,
1978). All the preceding three references are incorporated herein
by reference. In one example, the ridges are made from the
Merigraph series of resins made by Hercules Incorporated of
Wilmington, Del.
[0141] Once the proper quantity (and thickness) of liquid
photosensitive resin is coated on the woven belt, a cover film is
optionally applied to the exposed surface of the resin. The cover
film, which must be transparent to light of activating wave length,
serves primarily to protect the mask from direct contact with the
resin.
[0142] A mask (or negative) is placed directly on the optional
cover film or on the surface of the resin. This mask is formed of
any suitable material which can be used to shield or shade certain
portions of the liquid photosensitive resin from light while
allowing the light to reach other portions of the resin. The design
or geometry preselected for the ridges is, of course, reproduced in
this mask in regions which allow the transmission of light while
the geometries preselected for the gross foramina are in regions
which are opaque to light.
[0143] A rigid member such as a glass cover plate is placed atop
the mask and serves to aid in maintaining the upper surface of the
photosensitive liquid resin in a planar configuration.
[0144] The liquid photosensitive resin is then exposed to light of
the appropriate wave length through the cover glass, the mask, and
the cover film in such a manner as to initiate the curing of the
liquid photosensitive resin in the exposed areas. It is important
to note that when the described procedure is followed, resin which
would normally be in a shadow cast by a filament, which is usually
opaque to activating light, is cured. Curing this particular small
mass of resin aids in making the bottom side of the deflection
member planar and in isolating one deflection conduit from
another.
[0145] After exposure, the cover plate, the mask, and the cover
film are removed from the system. The resin is sufficiently cured
in the exposed areas to allow the woven belt along with the resin
to be stripped from the backing film.
[0146] Uncured resin is removed from the woven belt by any
convenient means such as vacuum removal and aqueous washing.
[0147] A section of the deflection member is now essentially in
final form. Depending upon the nature of the photosensitive resin
and the nature and amount of the radiation previously supplied to
it, the remaining, at least partially cured, photosensitive resin
can be subjected to further radiation in a post curing operation as
required.
[0148] The backing film is stripped from the forming table and the
process is repeated with another section of the woven belt.
Conveniently, the woven belt is divided off into sections of
essentially equal and convenient lengths which are numbered
serially along its length. Odd numbered sections are sequentially
processed to form sections of the deflection member and then even
numbered sections are sequentially processed until the entire belt
possesses the characteristics required of the deflection member.
The woven belt may be maintained under tension at all times.
[0149] In the method of construction just described, the knuckles
of the woven belt actually form a portion of the bottom surface of
the deflection member. The woven belt can be physically spaced from
the bottom surface.
[0150] Multiple replications of the above described technique can
be used to construct deflection members having the more complex
geometries.
[0151] The deflection member of the present invention may be made
or partially made according to U.S. Pat. No. 4,637,859, issued Jan.
20, 1987 to Trokhan.
[0152] As shown in FIG. 14, after the embryonic fibrous web 56 has
been associated with the deflection member 64, fibers within the
embryonic fibrous web 56 are deflected into the deflection conduits
present in the deflection member 64. In one example of this process
step, there is essentially no water removal from the embryonic
fibrous web 56 through the deflection conduits after the embryonic
fibrous web 56 has been associated with the deflection member 64
but prior to the deflecting of the fibers into the deflection
conduits. Further water removal from the embryonic fibrous web 56
can occur during and/or after the time the fibers are being
deflected into the deflection conduits. Water removal from the
embryonic fibrous web 56 may continue until the consistency of the
embryonic fibrous web 56 associated with deflection member 64 is
increased to from about 25% to about 35%. Once this consistency of
the embryonic fibrous web 56 is achieved, then the embryonic
fibrous web 56 is referred to as an intermediate fibrous web 84.
During the process of forming the embryonic fibrous web 56,
sufficient water may be removed, such as by a noncompressive
process, from the embryonic fibrous web 56 before it becomes
associated with the deflection member 64 so that the consistency of
the embryonic fibrous web 56 may be from about 10% to about
30%.
[0153] While applicants decline to be bound by any particular
theory of operation, it appears that the deflection of the fibers
in the embryonic web and water removal from the embryonic web begin
essentially simultaneously. Embodiments can, however, be envisioned
wherein deflection and water removal are sequential operations.
Under the influence of the applied differential fluid pressure, for
example, the fibers may be deflected into the deflection conduit
with an attendant rearrangement of the fibers. Water removal may
occur with a continued rearrangement of fibers. Deflection of the
fibers, and of the embryonic fibrous web, may cause an apparent
increase in surface area of the embryonic fibrous web. Further, the
rearrangement of fibers may appear to cause a rearrangement in the
spaces or capillaries existing between and/or among fibers.
[0154] It is believed that the rearrangement of the fibers can take
one of two modes dependent on a number of factors such as, for
example, fiber length. The free ends of longer fibers can be merely
bent in the space defined by the deflection conduit while the
opposite ends are restrained in the region of the ridges. Shorter
fibers, on the other hand, can actually be transported from the
region of the ridges into the deflection conduit (The fibers in the
deflection conduits will also be rearranged relative to one
another). Naturally, it is possible for both modes of rearrangement
to occur simultaneously.
[0155] As noted, water removal occurs both during and after
deflection; this water removal may result in a decrease in fiber
mobility in the embryonic fibrous web. This decrease in fiber
mobility may tend to fix and/or freeze the fibers in place after
they have been deflected and rearranged. Of course, the drying of
the web in a later step in the process of this invention serves to
more firmly fix and/or freeze the fibers in position.
[0156] Any convenient means conventionally known in the papermaking
art can be used to dry the intermediate fibrous web 84. Examples of
such suitable drying process include subjecting the intermediate
fibrous web 84 to conventional and/or flow-through dryers and/or
Yankee dryers.
[0157] In one example of a drying process, the intermediate fibrous
web 84 in association with the deflection member 64 passes around
the deflection member return roll 66 and travels in the direction
indicated by directional arrow 70. The intermediate fibrous web 84
may first pass through an optional predryer 86. This predryer 86
can be a conventional flow-through dryer (hot air dryer) well known
to those skilled in the art. Optionally, the predryer 86 can be a
so-called capillary dewatering apparatus. In such an apparatus, the
intermediate fibrous web 84 passes over a sector of a cylinder
having preferential-capillary-size pores through its
cylindrical-shaped porous cover. Optionally, the predryer 86 can be
a combination capillary dewatering apparatus and flow-through
dryer. The quantity of water removed in the predryer 86 may be
controlled so that a predried fibrous web 88 exiting the predryer
86 has a consistency of from about 30% to about 98%. The predried
fibrous web 88, which may still be associated with deflection
member 64, may pass around another deflection member return roll 66
and as it travels to an impression nip roll 68. As the predried
fibrous web 88 passes through the nip formed between impression nip
roll 68 and a surface of a Yankee dryer 90, the ridge pattern
formed by the top surface 72 of deflection member 64 is impressed
into the predried fibrous web 88 to form a linear element imprinted
fibrous web 92. The imprinted fibrous web 92 can then be adhered to
the surface of the Yankee dryer 90 where it can be dried to a
consistency of at least about 95%.
[0158] The imprinted fibrous web 92 can then be foreshortened by
creping the imprinted fibrous web 92 with a creping blade 94 to
remove the imprinted fibrous web 92 from the surface of the Yankee
dryer 90 resulting in the production of a creped fibrous structure
96 in accordance with the present invention. As used herein,
foreshortening refers to the reduction in length of a dry (having a
consistency of at least about 90% and/or at least about 95%)
fibrous web which occurs when energy is applied to the dry fibrous
web in such a way that the length of the fibrous web is reduced and
the fibers in the fibrous web are rearranged with an accompanying
disruption of fiber-fiber bonds. Foreshortening can be accomplished
in any of several well-known ways. One common method of
foreshortening is creping. The creped fibrous structure 96 may be
subjected to post processing steps such as calendaring, tuft
generating operations, and/or embossing and/or converting.
[0159] In addition to the Yankee fibrous structure making
process/method, the fibrous structures of the present invention may
be made using a Yankeeless fibrous structure making process/method.
Such a process oftentimes utilizes transfer fabrics to permit rush
transfer of the embryonic fibrous web prior to drying. The fibrous
structures produced by such a Yankeeless fibrous structure making
process oftentimes a substantially uniform density.
[0160] The molding member/deflection member of the present
invention may be utilized to imprint linear elements into a fibrous
structure during a through-air-drying operation.
[0161] However, such molding members/deflection members may also be
utilized as forming members upon which a fiber slurry is
deposited.
[0162] In one example, the linear elements of the present invention
may be formed by a plurality of non-linear element, such as
embossments and/or protrusions and/or depressions formed by a
molding member, that are arranged in a line having an overall
length of greater than about 4.5 mm and/or greater than about 10 mm
and/or greater than about 15 mm and/or greater than about 25 mm
and/or greater than about 30 mm.
[0163] In addition to imprinting linear elements into fibrous
structures during a fibrous structure making process/method, linear
elements may be created in a fibrous structure during a converting
operation of a fibrous structure. For example, linear elements may
be imparted to a fibrous structure by embossing linear elements
into a fibrous structure.
Nonlimiting Example
[0164] A fibrous structure in accordance with the present invention
is prepared using a fibrous structure making machine having a
layered headbox having a top chamber, a center chamber, and a
bottom chamber. A eucalyptus fiber slurry is pumped through the top
headbox chamber, a eucalyptus fiber slurry is pumped through the
bottom headbox chamber (i.e. the chamber feeding directly onto the
forming wire) and, finally, an NSK fiber slurry is pumped through
the center headbox chamber and delivered in superposed relation
onto the Fourdrinier wire to form thereon a three-layer embryonic
web, of which about 33% of the top side is made up of the
eucalyptus blended fibers, 33% is made of the eucalyptus fibers on
the bottom side and 33% is made up of the NSK fibers in the center.
Dewatering occurs through the Fourdrinier wire and is assisted by a
deflector and vacuum boxes. The Fourdrinier wire is of a 5-shed,
satin weave configuration having 87 machine-direction and 76
cross-machine-direction monofilaments per inch, respectively. The
speed of the Fourdrinier wire is about 750 fpm (feet per
minute).
[0165] The embryonic wet web is transferred from the Fourdrinier
wire, at a fiber consistency of about 15% at the point of transfer,
to a patterned drying fabric. The speed of the patterned drying
fabric is the same as the speed of the Fourdrinier wire. The drying
fabric is designed to yield a pattern of substantially machine
direction oriented linear channels having 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 45.times.52 filament, dual layer
mesh. The thickness of the resin cast is about 11 mils above the
supporting fabric.
[0166] Further de-watering is accomplished by vacuum assisted
drainage until the web has a fiber consistency of about 20% to
30%.
[0167] While remaining in contact with the patterned drying fabric,
the web is pre-dried by air blow-through pre-dryers to a fiber
consistency of about 65% by weight.
[0168] After the pre-dryers, the semi-dry web is transferred to the
Yankee dryer and adhered to the surface of the Yankee dryer with a
sprayed creping adhesive. The creping adhesive is an aqueous
dispersion with the actives consisting of about 22% polyvinyl
alcohol, about 11% CREPETROL A3025, and about 67% CREPETROL R6390.
CREPETROL A3025 and CREPETROL R6390 are commercially available from
Hercules Incorporated of Wilmington, Del. The creping adhesive is
delivered to the Yankee surface at a rate of about 0.15% adhesive
solids based on the dry weight of the web. The fiber consistency is
increased to about 97% before the web is dry creped from the Yankee
with a doctor blade.
[0169] The doctor blade has a bevel angle of about 25 degrees and
is positioned with respect to the Yankee dryer to provide an impact
angle of about 81 degrees. The Yankee dryer is operated at a
temperature of about 350.degree. F. (177.degree. C.) and a speed of
about 750 fpm. The fibrous structure is wound in a roll using a
surface driven reel drum having a surface speed of about 656 feet
per minute. The fibrous structure may be subjected to post
treatments such as embossing and/or tuft generating. The fibrous
structure may be subsequently converted into a two-ply sanitary
tissue product having a basis weight of about 39 g/m.sup.2. For
each ply, the outer layer having the eucalyptus fiber furnish is
oriented toward the outside in order to form the consumer facing
surfaces of the two-ply sanitary tissue product.
[0170] The sanitary tissue product is soft, flexible and
absorbent.
Test Methods
[0171] Unless otherwise specified, all tests described herein
including those described under the Definitions section and the
following test methods are conducted on samples that have been
conditioned in a conditioned room at a temperature of 73.degree.
F..+-.40.degree. F. (about 23.degree. C..+-.2.2.degree. C.) and a
relative humidity of 50%.+-.10% for 2 hours prior to the test. All
plastic and paper board packaging materials must be carefully
removed from the paper samples prior to testing. Discard any
damaged product. All tests are conducted in such conditioned
room.
Flexural Rigidity Test Method
[0172] This test is performed on 1 inch.times.6 inch (2.54
cm.+-.15.24 cm) strips of a fibrous structure sample. A Cantilever
Bending Tester such as described in ASTM Standard D 1388 (Model
5010, Instrument Marketing Services, Fairfield, N.J.) is used and
operated at a ramp angle of 41.5 .+-.0.5.degree. and a sample slide
speed of 0.5.+-.0.2 in/second (1.3.+-.0.5 cm/second). A minimum of
n=16 tests are performed on each sample from n=8 sample strips.
[0173] No fibrous structure sample which is creased, bent, folded,
perforated, or in any other way weakened should ever be tested
using this test. A non-creased, non-bent, non-folded,
non-perforated, and non-weakened in any other way fibrous structure
sample should be used for testing under this test.
[0174] From one fibrous structure sample of about 4 inch.times.6
inch (10.16 cm.times.15.24 cm), carefully cut using a 1 inch (2.54
cm) JDC Cutter (available from Thwing-Albert Instrument Company,
Philadelphia, Pa.) four (4) 1 inch (2.54 cm) wide by 6 inch (15.24
cm) long strips of the fibrous structure in the MD direction. From
a second fibrous structure sample from the same sample set,
carefully cut four (4) 1 inch (2.54 cm) wide by 6 inch (15.24 cm)
long strips of the fibrous structure in the CD direction. It is
important that the cut be exactly perpendicular to the long
dimension of the strip. In cutting non-laminated two-ply fibrous
structure strips, the strips should be cut individually. The strip
should also be free of wrinkles or excessive mechanical
manipulation which can impact flexibility. Mark the direction very
lightly on one end of the strip, keeping the same surface of the
sample up for all strips. Later, the strips will be turned over for
testing, thus it is important that one surface of the strip be
clearly identified, however, it makes no difference which surface
of the sample is designated as the upper surface.
[0175] Using other portions of the fibrous structure (not the cut
strips), determine the basis weight of the fibrous structure sample
in lbs/3000 ft.sup.2 and the caliper of the fibrous structure in
mils (thousandths of an inch) using the standard procedures
disclosed herein. Place the Cantilever Bending Tester level on a
bench or table that is relatively free of vibration, excessive heat
and most importantly air drafts. Adjust the platform of the Tester
to horizontal as indicated by the leveling bubble and verify that
the ramp angle is at 41.5.+-.0.5.degree.. Remove the sample slide
bar from the top of the platform of the Tester. Place one of the
strips on the horizontal platform using care to align the strip
parallel with the movable sample slide. Align the strip exactly
even with the vertical edge of the Tester wherein the angular ramp
is attached or where the zero mark line is scribed on the Tester.
Carefully place the sample slide bar back on top of the sample
strip in the Tester. The sample slide bar must be carefully placed
so that the strip is not wrinkled or moved from its initial
position.
[0176] Move the strip and movable sample slide at a rate of
approximately 0.5.+-.0.2 in/second (1.3.+-.0.5 cm/second) toward
the end of the Tester to which the angular ramp is attached. This
can be accomplished with either a manual or automatic Tester.
Ensure that no slippage between the strip and movable sample slide
occurs. As the sample slide bar and strip project over the edge of
the Tester, the strip will begin to bend, or drape downward. Stop
moving the sample slide bar the instant the leading edge of the
strip falls level with the ramp edge. Read and record the overhang
length from the linear scale to the nearest 0.5 mm. Record the
distance the sample slide bar has moved in cm as overhang length.
This test sequence is performed a total of eight (8) times for each
fibrous structure in each direction (MD and CD). The first four
strips are tested with the upper surface as the fibrous structure
was cut facing up. The last four strips are inverted so that the
upper surface as the fibrous structure was cut is facing down as
the strip is placed on the horizontal platform of the Tester.
[0177] The average overhang length is determined by averaging the
sixteen (16) readings obtained on a fibrous structure.
Overhang Length MD = Sum of 8 MD reading 8 ##EQU00001## Overhang
Length CD = Sum of 8 CD reading 8 ##EQU00001.2## Overhang Length
Total = Sum of all 16 reading 8 ##EQU00001.3## Bend Length MD =
Overhang Length MD 2 ##EQU00001.4## Bend Length CD = Overhang
Length CD 2 ##EQU00001.5## Bend Length Total = Overhang Length
Total 2 ##EQU00001.6## Flexural Rigidity = 0.1629 .times. W .times.
C 3 ##EQU00001.7##
wherein W is the basis weight of the fibrous structure in lbs/3000
ft.sup.2; C is the bending length (MD or CD or Total) in cm; and
the constant 0.1629 is used to convert the basis weight from
English to metric units. The results are expressed in mg-cm.
GM Flexural Rigidity=Square root of (MD Flexural Rigidity.times.CD
Flexural Rigidity)
Basis Weight Test Method
[0178] Basis weight of a fibrous structure sample is measured by
selecting twelve (12) usable units (also referred to as sheets) of
the fibrous structure and making two stacks of six (6) usable units
each. Perforation must be aligned on the same side when stacking
the usable units. A precision cutter is used to cut each stack into
exactly 8.89 cm.times.8.89 cm (3.5 in..times.3.5 in.) squares. The
two stacks of cut squares are combined to make a basis weight pad
of twelve (12) squares thick. The basis weight pad is then weighed
on a top loading balance with a minimum resolution of 0.01 g. The
top loading balance must be protected from air drafts and other
disturbances using a draft shield. Weights are recorded when the
readings on the top loading balance become constant. The Basis
Weight is calculated as follows:
Basis Weight ( lbs / 3000 ft 2 ) = Weight of basis weight pad ( g )
.times. 3000 ft 2 453.6 g / lbs .times. 12 ( usable units ) .times.
[ 12.25 in 2 ( Area of basis weight pad ) / 144 in 2 ] ##EQU00002##
Basis Weight ( g / m 2 ) = Weight of basis weight pad ( g ) .times.
10 , 000 cm 2 / m 2 79.0321 cm 2 ( Area of basis weight pad )
.times. 12 ( usable units ) ##EQU00002.2##
Caliper Test Method
[0179] Caliper of a fibrous structure is measured by cutting five
(5) samples of fibrous structure such that each cut sample is
larger in size than a load foot loading surface of a VIR Electronic
Thickness Tester Model II available from Thwing-Albert Instrument
Company, Philadelphia, Pa. Typically, the load foot loading surface
has a circular surface area of about 3.14 in.sup.2. The sample is
confined between a horizontal flat surface and the load foot
loading surface. The load foot loading surface applies a confining
pressure to the sample of 15.5 g/cm.sup.2. The caliper of each
sample is the resulting gap between the flat surface and the load
foot loading surface. The caliper is calculated as the average
caliper of the five samples. The result is reported in millimeters
(mm).
Elongation, Tensile Strength, TEA and Modulus Test Methods
[0180] Remove five (5) strips of four (4) usable units (also
referred to as sheets) of fibrous structures and stack one on top
of the other to form a long stack with the perforations between the
sheets coincident. Identify sheets 1 and 3 for machine direction
tensile measurements and sheets 2 and 4 for cross direction tensile
measurements. Next, cut through the perforation line using a paper
cutter (JDC-1-10 or JDC-1-12 with safety shield from Thwing-Albert
Instrument Co. of Philadelphia, Pa.) to make 4 separate stacks.
Make sure stacks 1 and 3 are still identified for machine direction
testing and stacks 2 and 4 are identified for cross direction
testing.
[0181] Cut two 1 inch (2.54 cm) wide strips in the machine
direction from stacks 1 and 3. Cut two 1 inch (2.54 cm) wide strips
in the cross direction from stacks 2 and 4. There are now four 1
inch (2.54 cm) wide strips for machine direction tensile testing
and four 1 inch (2.54 cm) wide strips for cross direction tensile
testing. For these finished product samples, all eight 1 inch (2.54
cm) wide strips are five usable units (sheets) thick.
[0182] For the actual measurement of the elongation, tensile
strength, TEA and modulus, use a Thwing-Albert Intelect II Standard
Tensile Tester (Thwing-Albert Instrument Co. of Philadelphia, Pa.).
Insert the flat face clamps into the unit and calibrate the tester
according to the instructions given in the operation manual of the
Thwing-Albert Intelect II. Set the instrument crosshead speed to
4.00 in/min (10.16 cm/min) and the 1st and 2nd gauge lengths to
2.00 inches (5.08 cm). The break sensitivity is set to 20.0 grams
and the sample width is set to 1.00 inch (2.54 cm) and the sample
thickness is set to 0.3937 inch (1 cm). The energy units are set to
TEA and the tangent modulus (Modulus) trap setting is set to 38.1
g.
[0183] Take one of the fibrous structure sample strips and place
one end of it in one clamp of the tensile tester. Place the other
end of the fibrous structure sample strip in the other clamp. Make
sure the long dimension of the fibrous structure sample strip is
running parallel to the sides of the tensile tester. Also make sure
the fibrous structure sample strips are not overhanging to the
either side of the two clamps. In addition, the pressure of each of
the clamps must be in full contact with the fibrous structure
sample strip.
[0184] After inserting the fibrous structure sample strip into the
two clamps, the instrument tension can be monitored. If it shows a
value of 5 grams or more, the fibrous structure sample strip is too
taut. Conversely, if a period of 2-3 seconds passes after starting
the test before any value is recorded, the fibrous structure sample
strip is too slack.
[0185] Start the tensile tester as described in the tensile tester
instrument manual. The test is complete after the crosshead
automatically returns to its initial starting position. When the
test is complete, read and record the following with units of
measure:
[0186] Peak Load Tensile (Tensile Strength) (g/in)
[0187] Peak Elongation (Elongation) (%)
[0188] Peak TEA (TEA) (in-g/in.sup.2)
[0189] Tangent Modulus (Modulus) (at 15 g/cm)
[0190] Test each of the samples in the same manner, recording the
above measured values from each test.
Calculations:
[0191] Geometric Mean (GM) Elongation=Square Root of [MD Elongation
(%).times.CD Elongation (%)]
Total Dry Tensile (TDT)=Peak Load MD Tensile (g/in)+Peak Load CD
Tensile (g/in)
Tensile Ratio=Peak Load MD Tensile (g/in)/Peak Load CD Tensile
(g/in)
Geometric Mean (GM) Tensile=[Square Root of (Peak Load MD Tensile
(g/in).times.Peak Load CD Tensile (g/in))].times.3
TEA=MD TEA (in-g/in.sup.2)+CD TEA (in-g/in.sup.2)
Geometric Mean (GM) TEA=Square Root of [MD TEA
(in-g/in.sup.2).times.CD TEA (in-g/in.sup.2)]
Modulus=MD Modulus (at 15 g/cm)+CD Modulus (at 15 g/cm)
Geometric Mean (GM) Modulus=Square Root of [MD Modulus (at 15
g/cm).times.CD Modulus (at 15 g/cm)]
Dry Burst Test Method
[0192] Fibrous structure samples for each condition to be tested
are cut to a size appropriate for testing (minimum sample size 4.5
inches.times.4.5 inches), a minimum of five (5) samples for each
condition to be tested are prepared.
[0193] A burst tester (Burst Tester Intelect-II-STD Tensile Test
Instrument, Cat. No. 1451-24PGB available from Thwing-Albert
Instrument Co., Philadelphia, Pa.) is set up according to the
manufacturer's instructions and the following conditions: Speed:
12.7 centimeters per minute; Break Sensitivity: 20 grams; and Peak
Load: 2000 grams. The load cell is calibrated according to the
expected burst strength.
[0194] A fibrous structure sample to be tested is clamped and held
between the annular clamps of the burst tester and is subjected to
increasing force that is applied by a 0.625 inch diameter, polished
stainless steel ball upon operation of the burst tester according
to the manufacturer's instructions. The burst strength is that
force that causes the sample to fail.
[0195] The burst strength for each fibrous structure sample is
recorded. An average and a standard deviation for the burst
strength for each condition is calculated.
[0196] The Dry Burst is reported as the average and standard
deviation for each condition to the nearest gram.
Horizontal Full Sheet (HFS) Test Method
[0197] The Horizontal Full Sheet (HFS) test method determines the
amount of distilled water absorbed and retained by a fibrous
structure of the present invention. This method is performed by
first weighing a sample of the fibrous structure to be tested
(referred to herein as the "dry weight of the sample"), then
thoroughly wetting the sample, draining the wetted sample in a
horizontal position and then reweighing (referred to herein as "wet
weight of the sample"). The absorptive capacity of the sample is
then computed as the amount of water retained in units of grams of
water absorbed by the sample. When evaluating different fibrous
structure samples, the same size of fibrous structure is used for
all samples tested.
[0198] The apparatus for determining the HFS capacity of fibrous
structures comprises the following:
[0199] 1) An electronic balance with a sensitivity of at least
+0.01 grams and a minimum capacity of 1200 grams. The balance
should be positioned on a balance table and slab to minimize the
vibration effects of floor/benchtop weighing. The balance should
also have a special balance pan to be able to handle the size of
the sample tested (i.e.; a fibrous structure sample of about 11 in.
(27.9 cm) by 11 in. (27.9 cm)). The balance pan can be made out of
a variety of materials. Plexiglass is a common material used.
[0200] 2) A sample support rack (FIG. 16) and sample support rack
cover (FIG. 17) is also required. Both the rack and cover are
comprised of a lightweight metal frame, strung with 0.012 in.
(0.305 cm) diameter monofilament so as to form a grid as shown in
FIG. 16. The size of the support rack and cover is such that the
sample size can be conveniently placed between the two.
[0201] The HFS test is performed in an environment maintained at
23.+-.1.degree. C. and 50.+-.2% relative humidity. A water
reservoir or tub is filled with distilled water at 23.+-.1.degree.
C. to a depth of 3 inches (7.6 cm).
[0202] Eight samples of a fibrous structure to be tested are
carefully weighed on the balance to the nearest 0.01 grams. The dry
weight of each sample is reported to the nearest 0.01 grams. The
empty sample support rack is placed on the balance with the special
balance pan described above. The balance is then zeroed (tared).
One sample is carefully placed on the sample support rack. The
support rack cover is placed on top of the support rack. The sample
(now sandwiched between the rack and cover) is submerged in the
water reservoir. After the sample is submerged for 60 seconds, the
sample support rack and cover are gently raised out of the
reservoir.
[0203] The sample, support rack and cover are allowed to drain
horizontally for 120.+-.5 seconds, taking care not to excessively
shake or vibrate the sample. While the sample is draining, the rack
cover is carefully removed and all excess water is wiped from the
support rack. The wet sample and the support rack are weighed on
the previously tared balance. The weight is recorded to the nearest
0.01 g. This is the wet weight of the sample.
[0204] The gram per fibrous structure sample absorptive capacity of
the sample is defined as (wet weight of the sample-dry weight of
the sample). The horizontal absorbent capacity (HAC) is defined as:
absorbent capacity=(wet weight of the sample-dry weight of the
sample)/(dry weight of the sample) and has a unit of gram/gram.
Vertical Full Sheet (VFS) Test Method
[0205] The Vertical Full Sheet (VFS) test method determines the
amount of distilled water absorbed and retained by a fibrous
structure of the present invention. This method is performed by
first weighing a sample of the fibrous structure to be tested
(referred to herein as the "dry weight of the sample"), then
thoroughly wetting the sample, draining the wetted sample in a
vertical position and then reweighing (referred to herein as "wet
weight of the sample"). The absorptive capacity of the sample is
then computed as the amount of water retained in units of grams of
water absorbed by the sample. When evaluating different fibrous
structure samples, the same size of fibrous structure is used for
all samples tested.
[0206] The apparatus for determining the VFS capacity of fibrous
structures comprises the following:
[0207] 1) An electronic balance with a sensitivity of at least
.+-.0.01 grams and a minimum capacity of 1200 grams. The balance
should be positioned on a balance table and slab to minimize the
vibration effects of floor/benchtop weighing. The balance should
also have a special balance pan to be able to handle the size of
the sample tested (i.e.; a fibrous structure sample of about 11 in.
(27.9 cm) by 11 in. (27.9 cm)). The balance pan can be made out of
a variety of materials. Plexiglass is a common material used. 2) A
sample support rack (FIG. 16) and sample support rack cover (FIG.
17) is also required. Both the rack and cover are comprised of a
lightweight metal frame, strung with 0.012 in. (0.305 cm) diameter
monofilament so as to form a grid as shown in FIG. 16. The size of
the support rack and cover is such that the sample size can be
conveniently placed between the two.
[0208] The VFS test is performed in an environment maintained at
23.+-.1.degree. C. and 50.+-.2% relative humidity. A water
reservoir or tub is filled with distilled water at 23.+-.1.degree.
C. to a depth of 3 inches (7.6 cm).
[0209] Eight 19.05 cm (7.5 inch).times.19.05 cm (7.5 inch) to 27.94
cm (11 inch).times.27.94 cm (11 inch) samples of a fibrous
structure to be tested are carefully weighed on the balance to the
nearest 0.01 grams. The dry weight of each sample is reported to
the nearest 0.01 grams. The empty sample support rack is placed on
the balance with the special balance pan described above. The
balance is then zeroed (tared). One sample is carefully placed on
the sample support rack. The support rack cover is placed on top of
the support rack. The sample (now sandwiched between the rack and
cover) is submerged in the water reservoir. After the sample is
submerged for 60 seconds, the sample support rack and cover are
gently raised out of the reservoir.
[0210] The sample, support rack and cover are allowed to drain
vertically for 60.+-.5 seconds, taking care not to excessively
shake or vibrate the sample. While the sample is draining, the rack
cover is carefully removed and all excess water is wiped from the
support rack. The wet sample and the support rack are weighed on
the previously tared balance. The weight is recorded to the nearest
0.01 g. This is the wet weight of the sample.
[0211] The procedure is repeated for with another sample of the
fibrous structure, however, the sample is positioned on the support
rack such that the sample is rotated 90.degree. compared to the
position of the first sample on the support rack.
[0212] The gram per fibrous structure sample absorptive capacity of
the sample is defined as (wet weight of the sample-dry weight of
the sample). The calculated VFS is the average of the absorptive
capacities of the two samples of the fibrous structure.
Dimensions of Linear Element/Linear Element Forming Component Test
Method
[0213] The length of a linear element in a fibrous structure and/or
the length of a linear element forming component in a molding
member is measured by image scaling of a light microscopy image of
a sample of fibrous structure.
[0214] A light microscopy image of a sample to be analyzed such as
a fibrous structure or a molding member is obtained with a
representative scale associated with the image. The images is saved
as a *.tiff file on a computer. Once the image is saved,
SmartSketch, version 05.00.35.14 software made by Intergraph
Corporation of Huntsville, Ala., is opened. Once the software is
opened and running on the computer, the user clicks on "New" from
the "File" drop-down panel. Next, "Normal" is selected.
"Properties" is then selected from the "File" drop-down panel.
Under the "Units" tab, "mm" (millimeters) is chosen as the unit of
measure and "0.123" as the precision of the measurement. Next,
"Dimension" is selected from the "Format" drop-down panel. Click
the "Units" tab and ensure that the "Units" and "Unit Labels" read
"mm" and that the "Round-Off" is set at "0.123." Next, the
"rectangle" shape from the selection panel is selected and dragged
into the sheet area. Highlight the top horizontal line of the
rectangle and set the length to the corresponding scale indicated
light microscopy image. This will set the width of the rectangle to
the scale required for sizing the light microscopy image. Now that
the rectangle has been sized for the light microscopy image,
highlight the top horizontal line and delete the line. Highlight
the left and right vertical lines and the bottom horizontal line
and select "Group". This keeps each of the line segments grouped at
the width dimension ("mm") selected earlier. With the group
highlighted, drop the "line width" panel down and type in "0.01
mm." The scaled line segment group is now ready to use for scaling
the light microscopy image can be confirmed by right-clicking on
the "dimension between", then clicking on the two vertical line
segments.
[0215] To insert the light microscopy image, click on the "Image"
from the "insert" drop-down panel. The image type is preferably a
*.tiff format. Select the light microscopy image to be inserted
from the saved file, then click on the sheet to place the light
microscopy image. Click on the right bottom corner of the image and
drag the corner diagonally from bottom-right to top-left. This will
ensure that the image's aspect ratio will not be modified. Using
the "Zoom In" feature, click on the image until the light
microscopy image scale and the scale group line segments can be
seen. Move the scale group segment over the light microscopy image
scale. Increase or decrease the light microscopy image size as
needed until the light microscopy image scale and the scale group
line segments are equal. Once the light microscopy image scale and
the scale group line segments are visible, the object(s) depicted
in the light microscopy image can be measured using "line symbols"
(located in the selection panel on the right) positioned in a
parallel fashion and the "Distance Between" feature. For length and
width measurements, a top view of a fibrous structure and/or
molding member is used as the light microscopy image. For a height
measurement, a side or cross sectional view of the fibrous
structure and/or molding member is used as the light microscopy
image.
[0216] 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."
[0217] Every document cited herein, including any cross referenced
or related patent or application, is hereby incorporated herein by
reference in its entirety unless expressly excluded or otherwise
limited. The citation of any document 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 incorporated by reference, the meaning
or definition assigned to that term in this document shall
govern.
[0218] 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.
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