U.S. patent application number 11/713930 was filed with the patent office on 2008-09-11 for deeply embossed roll paper products having reduced gapping on the machine direction edges.
Invention is credited to James Paul Farwig, Nicholas Jerome Wilke.
Application Number | 20080216975 11/713930 |
Document ID | / |
Family ID | 39684129 |
Filed Date | 2008-09-11 |
United States Patent
Application |
20080216975 |
Kind Code |
A1 |
Farwig; James Paul ; et
al. |
September 11, 2008 |
Deeply embossed roll paper products having reduced gapping on the
machine direction edges
Abstract
A roll paper product having a machine direction, cross machine
direction, two machine direction edges, and one or more plies of a
fibrous structure having a pattern embossed on the surface thereof
wherein the embossing pattern has a plurality of embossments having
a height, one or more first tracts having a cross machine direction
width, and one or more second tracts having a cross machine
direction width, wherein the first tract has the lower percent
unembossed than the second tract; and wherein the roll paper
product has been cut such that at least one machine direction edge
is tangential to a first tract.
Inventors: |
Farwig; James Paul;
(Cincinnati, OH) ; Wilke; Nicholas Jerome;
(Independence, KY) |
Correspondence
Address: |
THE PROCTER & GAMBLE COMPANY;INTELLECTUAL PROPERTY DIVISION - WEST BLDG.
WINTON HILL BUSINESS CENTER - BOX 412, 6250 CENTER HILL AVENUE
CINCINNATI
OH
45224
US
|
Family ID: |
39684129 |
Appl. No.: |
11/713930 |
Filed: |
March 5, 2007 |
Current U.S.
Class: |
162/109 |
Current CPC
Class: |
B31F 1/07 20130101; B31F
2201/0794 20130101; B31F 2201/0738 20130101; B31F 2201/0733
20130101 |
Class at
Publication: |
162/109 |
International
Class: |
D21H 27/02 20060101
D21H027/02 |
Claims
1. A roll paper product comprising a machine direction, cross
machine direction, two machine direction edges, and one or more
plies of a fibrous structure having a pattern embossed on the
surface thereof: wherein the embossing pattern comprises a
plurality of embossments having a height, one or more first tracts
having a cross machine direction width, and one or more second
tracts having a cross machine direction width, wherein the first
tract has the lower percent unembossed than the second tract; and
wherein the roll paper product has been cut such that at least one
machine direction edge is tangential to a first tract.
2. The roll paper product according to claim 1 wherein the machine
direction edges are tangential from about 1/4 to about 3/4 of the
cross machine direction width of one or more first tracts.
3. The roll paper product according to claim 2 wherein the machine
direction edges are tangential from about 1/3 to about 2/3 of the
cross machine direction width of one or more first tracts.
4. The roll paper product according to claim 3 wherein the machine
direction edges are tangential from about a midpoint of the cross
machine direction width of one or more first tracts.
5. The roll paper product according to claim 1 wherein the
embossments have a height of from about 650 .mu.m to about 4000
.mu.m.
6. The roll paper product according to claim 5 wherein the
embossments have a height of from about 900 .mu.m to about 1800
.mu.m.
7. A roll paper product according to claim 1 wherein a first tract
and a second tract further comprises an Unemboss to Emboss factor
of from about 1 to about 2.3.
8. A roll paper product according to claim 7 wherein the first
tract and the second tract comprises an Unemboss to Emboss factor
of from about 1.5 to about 2.
9. A roll paper product according to claim 1 wherein the first
tracts have a percent unembossed of from about 0% to about 40%.
10. A roll paper product according to claim 9 wherein the first
tracts have a percent unembossed of from about 0% to about 25%.
11. A roll paper product according to claim 1 wherein the roll
paper product has a length of from about 3 inches to about 13
inches.
12. A roll paper product according to claim 11 wherein the roll
paper product has a length of from about 4 inches to about 11
inches.
13. A roll paper product according to claim 1 wherein the roll
paper product is a paper towel product.
14. A method for cutting a paper log into rolls of paper product
wherein the method comprises: providing a paper log comprising a
machine direction, a cross machine direction, and one or more plies
of a fibrous structure; dividing the surface of the embossed paper
plies into two or more tracts along the machine direction;
measuring the percent of unembossed areas within each tract and
identifying one or more first tracts having a cross machine
direction width and one or more second tracts having a cross
machine direction width wherein the one or more first tracts have a
lower percent of unembossed areas than the one or more second
tracts; and cutting the paper log to form roll paper products
comprising a machine direction, a cross machine direction, one or
more plies of an embossed paper product, and 2 machine direction
edges; wherein the paper log is cut such that at least one machine
direction edge is tangential to a first tract.
15. The method according to claim 14 wherein the paper log is cut
such that the machine direction edge is tangential to from about
1/4 to about 3/4 of the cross machine direction width of the first
tract.
16. The method according to claim 15 wherein the paper log is cut
such that the machine direction edge is tangential to from about a
midpoint of the cross machine direction width of the first
tract.
17. The method according to claim 14 wherein the embossments have a
height of from about 650 .mu.m to about 4000 .mu.m.
18. The method according to claim 17 wherein the embossments have a
height of from about 900 .mu.m to about 1800 .mu.m.
19. The method according to claim 14 wherein the paper log is from
about 80 inches to about 120 inches in length.
20. The method according to claim 14 wherein the paper towel rolls
are from about 3 inches to about 13 inches in length.
21. A roll paper product comprising a machine direction, cross
machine direction, two machine direction edges, and one or more
plies of a cellulosic fibrous structure having a pattern embossed
on the surface thereof: wherein the embossing pattern comprises a
plurality of embossments having a height of from about 900 .mu.m to
about 1800 .mu.m, one or more first tracts having a cross machine
direction width, and one or more second tracts having a cross
machine direction width, wherein the first tracts has a lower
percent unembossed than the second tracts and wherein a first tract
and a second tract comprise an Unemboss to Emboss factor of from
about 1 to about 2.3; wherein the roll paper product has been cut
such that at least one edge is tangential to from about 1/3 to
about 2/3 of the cross machine direction width of a first tract;
and wherein the roll paper product has a length of from about 3
inches to about 13 inches.
Description
FIELD OF THE INVENTION
[0001] This invention is directed to a roll paper product having
highly defined embossments and wherein the roll paper product is
such that it has the appearance of tightly packed, or
non-corrugated, edges.
BACKGROUND OF THE INVENTION
[0002] Consumers often make conclusions regarding the quality of a
product based on the product's appearance. For example, a consumer
may make a judgment about a product based on its appearance while
the product is on the shelf. However, many consumers do not stop
opining about a product once they take the product home. Many
consumers may make a second judgment about the product based on the
product's appearance again once the product is being used in that
consumer's home. That being said, providing a positive visual
experience to the consumer may provide a variety of obstacles for a
manufacturer. For instance, increasing the visibility of one
positive visual aspect of a product may cause another positive
visual aspect of that product to decrease.
[0003] Some products have certain qualities associated with certain
visual signals. For example, a roll paper towel product that has
deep, crisp, and clear embossments tends to convey a product that
is highly absorbent, strong, and soft. Similarly, a roll paper
towel product in which the surfaces formed from the plies of paper
being wound around an axis, or machine direction edges, of the roll
do not have many gaps or spaces is perceived by the consumer to
provide a good value because it is often thought that a roll paper
product having less corrugation has more sheets than a roll paper
product having more corrugation. However, when a roll paper product
has exceptionally deep embossing, this roll paper product tends to
cause the edges of the roll to have a higher level of corrugation
than roll paper products with less deep embossing and the same
number of sheets.
[0004] Thus, there exists the need for roll paper products and
methods of cutting rolled paper products to optimize the machine
direction edges of the cut rolls such that the consumer will not
make any negative conclusions about the product.
SUMMARY OF THE INVENTION
[0005] The present invention relates to a roll paper product
comprising a machine direction, cross machine direction, two
machine direction edges, and one or more plies of a fibrous
structure having a pattern embossed on the surface thereof, wherein
the embossing pattern comprises a plurality of embossments having a
height, one or more first tracts having a cross machine direction
width, and one or more second tracts having a cross machine
direction width, wherein the first tract has the lower percent
unembossed than the second tract; and wherein the roll paper
product has been cut such that at least one machine direction edge
is tangential to a first tract.
[0006] In another embodiment, the present invention relates to a
method for cutting a paper log into rolls of paper product wherein
the method comprises: providing a paper log comprising a machine
direction, a cross machine direction, and one or more plies of a
fibrous structure; dividing the surface of the embossed paper plies
into two or more tracts along the machine direction; measuring the
percent of unembossed areas within each tract and identifying one
or more first tracts having a cross machine direction width and one
or more second tracts having a cross machine direction width
wherein the one or more first tracts have a lower percent of
unembossed areas than the one or more second tracts; and cutting
the paper log to form roll paper products comprising a machine
direction, a cross machine direction, one or more plies of an
embossed paper product, and 2 machine direction edges; wherein the
paper log is cut such that at least one machine direction edge is
tangential to a first tract.
[0007] In another embodiment, the present invention relates to a
roll paper product comprising a machine direction, cross machine
direction, two machine direction edges, and one or more plies of a
cellulosic fibrous structure having a pattern embossed on the
surface thereof: wherein the embossing pattern comprises a
plurality of embossments having a height of from about 900 .mu.m to
about 1800 .mu.m, one or more first tracts having a cross machine
direction width, and one or more second tracts having a cross
machine direction width, wherein the first tracts has a lower
percent unembossed than the second tracts and wherein a first tract
and a second tract comprise an Unemboss to Emboss factor of from
about 1 to about 2.3; wherein the roll paper product has been cut
such that at least one edge is tangential to from about 1/3 to
about 2/3 of the cross machine direction width of a first tract;
and wherein the roll paper product has a length of from about 3
inches to about 13 inches.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a schematic side view of one embodiment of an
apparatus that can be used to perform the deep-nested embossing of
the present invention.
[0009] FIG. 2 is an enlarged side view of the nip formed between
the embossing rolls of the apparatus shown in FIG. 1.
[0010] FIG. 3 is a schematic side view of one embodiment of an
apparatus that can be used to perform the deep-nested embossing of
the present invention.
[0011] FIG. 4 is a schematic side view of an alternative apparatus
that can be used to perform the deep-nested embossing of the
present invention.
[0012] FIG. 5 is a side view of the gap between two engaged emboss
cylinders of the apparatus for deep-nested embossing of the present
invention.
[0013] FIG. 6 is a side view of an embodiment of the embossed paper
product of the present invention.
[0014] FIG. 7 is a plan view of an embodiment of one section of an
emboss pattern that may be applied to the surface of the embossed
paper product of the present invention.
[0015] FIG. 8A is a plan view of an embodiment of one section of an
emboss pattern that may be applied to the surface of the embossed
paper product produced of the present invention.
[0016] FIG. 8B is a plan view of an embodiment of one section of an
emboss pattern that may be applied to the surface of the embossed
paper product produced by the process of the present invention.
[0017] FIG. 9A is a plan view of an embodiment of a paper log that
may be used by the process of the present invention.
[0018] FIG. 9B is a front view of an embodiment of a paper log that
may be used by the process of the present invention.
[0019] FIG. 10A is a plan view of an embodiment of a paper roll
that has been cut from the paper log of FIGS. 9A-B along lines
550-550 and 560-560.
[0020] FIG. 10B is a plan view of an embodiment of a paper roll
that has been cut from the paper log of FIGS. 9A-B along lines
550-550 and 560-560.
[0021] FIG. 11A is a photograph of an embodiment of an edge of a
roll of paper product that has been cut by the process of the
present invention.
[0022] FIG. 11B is a photograph of an embodiment of an edge of a
roll of paper product that has been cut by the process of the
present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0023] As used herein, "paper product" refers to any formed,
fibrous structure products, traditionally, but not necessarily,
comprising cellulose fibers. In one embodiment, the paper products
of the present invention may include tissue-towel paper products
and toilet tissue products.
[0024] As used herein, "roll paper product" refers to any paper
product that is wound about an axis. In an embodiment, a roll paper
product is provided by winding a paper product around a core.
[0025] As used herein, "ply" or "plies", as used herein, means an
individual fibrous structure or sheet of fibrous structure,
optionally to be disposed in a substantially contiguous,
face-to-face relationship with other plies, forming a multi-ply
fibrous structure. It is also contemplated that a single fibrous
structure can effectively form two "plies" or multiple "plies", for
example, by being folded on itself. In one embodiment, the ply has
an end use as a tissue-towel paper product. A ply may comprise one
or more wet-laid layers, air-laid layers, and/or combinations
thereof. If more than one layer is used, it is not necessary for
each layer to be made from the same fibrous structure. Further, the
layers may or may not be homogenous within a layer. The actual
makeup of a fibrous structure product ply is generally determined
by the desired benefits of the final tissue-towel paper product, as
would be known to one of skill in the art. The fibrous structure
may comprise one or more plies of non-woven materials in addition
to the wet-laid and/or air-laid plies.
[0026] As used herein, "fibrous structure" means an arrangement of
fibers produced in any papermaking machine known in the art to
create a ply of paper. "Fiber" means an elongate particulate having
an apparent length greatly exceeding its apparent width. More
specifically, and as used herein, fiber refers to such fibers
suitable for a papermaking process. The present invention
contemplates the use of a variety of paper making fibers, such as,
natural fibers, synthetic fibers, as well as any other suitable
fibers, starches, and combinations thereof. Paper making 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; mechanical pulps
including groundwood, thermomechanical pulp; chemithermomechanical
pulp; chemically modified pulps, and the like. Chemical pulps, are
particularly well suited in tissue towel embodiments since they are
known to those of skill in the art to impart a superior tactical
sense of softness to tissue sheets made therefrom. Pulps derived
from deciduous trees (hardwood) and/or coniferous trees (softwood)
can be utilized herein. Such hardwood and softwood fibers can be
blended or deposited in layers to provide a stratified web.
Exemplary layering embodiments and processes of layering are
disclosed in U.S. Pat. Nos. 3,994,771 and 4,300,981. Additionally,
fibers derived from non-wood pulp such as cotton linters, bagesse,
and the like, can be used. Additionally, fibers derived from
recycled paper, which may contain any or all of the pulp categories
listed above, as well as other non-fibrous materials such as
fillers and adhesives used to manufacture the original paper
product may be used in the present web. In addition, fibers and/or
filaments made from polymers, specifically hydroxyl polymers, may
be used in the present invention. Non-limiting examples of suitable
hydroxyl polymers include polyvinyl alcohol, starch, starch
derivatives, chitosan, chitosan derivatives, cellulose derivatives,
gums, arabinans, galactans, and combinations thereof. Additionally,
other synthetic fibers such as rayon, lyocel, polyester,
polyethylene, and polypropylene fibers can be used within the scope
of the present invention. Further, such fibers may be latex bonded.
Other materials are also intended to be within the scope of the
present invention as long as they do not interfere or counter act
any advantage presented by the instant invention.
[0027] As used herein, "Machine Direction" or "MD" means the
direction parallel to the flow of the fibrous structure through the
papermaking machine and/or product manufacturing equipment.
[0028] As used herein, "Cross Machine Direction" or "CD" means the
direction perpendicular to the machine direction in the same plane
of the fibrous structure and/or fibrous structure product
comprising the fibrous structure.
[0029] As used herein, "Machine Direction pitch" or "MD pitch"
means the distance between the centers of two emboss protrusions
that are adjacent and collinear in the machine direction.
[0030] As used herein, "Cross Machine Direction pitch" or "CD
pitch" means the distance between the centers of two emboss
protrusions that are adjacent and collinear in the cross machine
direction.
[0031] As used herein, "Machine Direction edge" or "MD edge" means
the surface of a roll paper product parallel to the machine
direction that is formed as a result of the sheets of roll paper
product being wound about an axis.
[0032] As used herein "paper log" or "log" refers to a long roll of
paper that has not been cut into smaller rolls that are suitable
for sale to consumers. Paper logs may be from about 80 inches to
about 120 inches in length and from about 3 inches to about 8
inches in diameter. In one embodiment a paper log may be disposed
around an inner core that may be made of any suitable material for
supporting the paper log.
[0033] As used herein, "tract" refers to one or more bands that
divides an emboss pattern. In one embodiment, a tract comprises
boundaries that are parallel in the machine direction.
Embossing
[0034] The embossing of webs, such as the paper webs that are used
to make paper products, is well known in the art. Embossing of webs
can provide improvements to the web such as increased bulk,
improved water holding capacity, improved aesthetics and other
benefits. Both single ply and multiple ply (or multi-ply) webs are
known in the art and can be embossed. Multi-ply paper webs are webs
that include at least two plies superimposed in face-to-face
relationship to form a laminate.
[0035] During a typical embossing process, a web is fed through a
nip formed between juxtaposed generally axially parallel rolls or
cylinders. Embossing protrusions on the rolls co7 mpress and/or
deform the web. If a multi-ply product is being formed, two or more
plies are fed through the nip and regions of each ply are brought
into a contacting relationship with the opposing ply. The embossed
regions of the plies may produce an aesthetic pattern and provide a
means for joining and maintaining the plies in face-to-face
contacting relationship.
[0036] Embossing is typically performed by one of two processes;
knob-to-knob embossing or nested embossing. Knob-to-knob embossing
typically consists of generally axially parallel rolls juxtaposed
to form a nip within which the embossing protrusions, or knobs, on
opposing rolls are aligned to press the web between the faces of
the aligned protrusions. Nested embossing typically consists of
embossing protrusions of one roll meshed in between the embossing
protrusions of the other roll. Examples of knob-to-knob embossing
and nested embossing are illustrated in the prior art by U.S. Pat.
Nos. 3,414,459, 3,547,723, 3,556,907, 3,708,366, 3,738,905,
3,867,225, 4,483,728, 5,468,323, 6,086,715, 6,277,466, 6,395,133,
and 6,846,172 B2.
[0037] Knob-to-knob embossing generally produces a web comprising
very compressed areas and surrounding pillowed regions which can
enhance the thickness of the product. However, the pillows have a
tendency to collapse under pressure due to lack of support.
Consequently, the thickness benefit is typically lost during the
balance of the converting operation and subsequent packaging,
diminishing the quilted appearance and/or thickness benefit sought
by the embossing.
[0038] Nested embossing has proven in some cases to be a more
desirable process for producing products exhibiting a softer, more
quilted appearance that can be maintained throughout the balance of
the converting process, including packaging. As the two plies
travel through the nip of the embossing rolls, the patterns are
meshed together. Nested embossing aligns the knob crests on the
male embossing roll with the low areas on the female embossing
roll. As a result, the embossed sites produced on one side of the
structure provide support for the uncontacted side of the structure
and the structure between embossment sites.
[0039] Another type of embossing, deep-nested embossing has been
developed and used to provide unique characteristics to the
embossed web. Deep-nested embossing refers to embossing that
utilizes paired emboss rolls, wherein the protrusions from the
different emboss rolls are coordinated such that the protrusions of
one roll fit into the spaces between the protrusions of the other
emboss roll. Exemplary deep-nested embossing techniques are
described in U.S. Pat. Nos. 5,686,168 and 5,294,475; U.S. patent
application Ser. Nos. 11/059,986 and 10/700,131 and U.S. Patent
Provisional Application Ser. No. 60/573,727. Exemplary high
definition embossing techniques are described in U.S. patent
application Ser. No. 11/516,892 and U.S. Ser. No. 10/952,119.
[0040] An exemplary process for embossing a web substrate in
accordance with the present invention incorporates the use of a
deep-nested embossment technology. By way of a non-limiting
example, a tissue ply structure is embossed in a gap between two
embossing rolls. The embossing rolls may be made from any material
known for making such rolls, including, without limitation, steel,
rubber, elastomeric materials, and combinations thereof. As known
to those of skill in the art, each embossing roll may be provided
with a combination of emboss protrusions and gaps. Each emboss
protrusion comprises a base, a face, and one or more sidewalls.
Each emboss protrusion also has a height, h. The height of the
emboss protrusions may range from about 1.8 mm. (0.070 in.) to
about 3.8 mm. (0.150 in.), preferably from about 2.0 mm. (0.080
in.) to about 3.3 mm. (0.130 in.).
[0041] FIG. 1 shows one embodiment of the apparatus 10 of the
present invention. The apparatus 10 includes a pair of rolls, first
embossing roll 20 and second embossing roll 30. (It should be noted
that the embodiments shown in the figures are just exemplary
embodiments and other embodiments are certainly contemplated. For
example, the embossing rolls 20 and 30 of the embodiment shown in
FIG. 1 could be replaced with any other embossing members such as,
for example, plates, cylinders or other equipment suitable for
embossing webs. Further, additional equipment and steps that are
not specifically described herein may be added to the apparatus
and/or process of the present invention.) The embossing rolls 20
and 30 are disposed adjacent each other to provide a nip 40. The
rolls 20 and 30 are generally configured so as to be rotatable on
an axis, the axes 22 and 32, respectively, of the rolls 20 and 30
are typically generally parallel to one another. The apparatus 10
may be contained within a typical embossing device housing. Each
roll has an outer surface 25 and 35 comprising a plurality of first
embossing protrusions 50 and second embossing protrusions 60 (shown
in more detail in FIG. 2) which are generally arranged in a
non-random pattern. The embossing rolls 20 and 30, including the
respective surfaces 25 and 35 of the rolls 20 and 30 as well as the
embossing protrusions 50 and 60, may be made out of any material
suitable for the desired embossing process. Such materials include,
without limitation, steel and other metals, ebonite, and hard
rubber or a combination thereof. As shown in FIG. 1, the first and
second embossing rolls 20 and 30 provide a nip 40 through which a
web 100 can pass. In the embodiment shown, a web 100 is made up of
a single ply 80 and is shown passing through the nip 40 in the
machine direction MD where it is embossed.
[0042] FIG. 2 is an enlarged view of the portion of the apparatus
10 (identified by callout 2 in FIG. 1.) The figure shows a more
detailed view of the web 100 passing through the nip 40 between the
first embossing roll 20 and the second embossing roll 30. As can be
seen in FIG. 2, the first embossing roll 20 includes a plurality of
first embossing protrusions 50 extending from the outer surface 25
of the first embossing roll 20. The second embossing roll also
includes a plurality of second embossing protrusions 60 extending
outwardly from the outer surface 35 of the second embossing roll
30. (It should be noted that when the embossing protrusions 50
and/or 60 are described as extending from a surface of an embossing
member, the embossing protrusions may be integral with the surface
of the embossing member or may be separate protrusions that are
joined to the surface of the embossing member.) As the ply of the
unconverted web 80 is passed through the nip 40, it is nested and
macroscopically deformed by the intermeshing of the first embossing
protrusions 50 and the second embossing protrusions 60. The
embossing shown is deep-nested embossing, as described herein,
because the first embossing protrusions 50 and the second embossing
protrusions 60 intermesh with each other, for example like the
teeth of gears. Thus, the resulting embossed web 100 is deeply
embossed and nested, as will be described in more detail below, and
includes plurality of undulations that can add bulk and caliper to
the web 100.
[0043] While the apparatus shown in FIG. 1 may be used for webs
having one ply, the apparatus may be used to make multi-ply
products as well. FIG. 3 shows an embodiment to the process of the
present invention where a two ply product is produced where both
plies are embossed. The first ply 80 and second ply 90 and
resulting web 100 are first joined together between marrying roll
70 and the first embossing roll 20. The plies 80 and 90 can be
joined together by any known means, but typically an adhesive
application system is used to apply adhesive to one or both of the
plies 80 and 90 prior to the plies being passed between the nip 75
formed between the marrying roll 70 and the first embossing roll
20. The combined web 100 is then passed through the nip 40 formed
between the first embossing roll 20 and the second embossing roll
30 where it is embossed.
[0044] In yet another possible embodiment of the present invention
to produce multi-ply products, as shown in FIG. 4, the plies 80 and
90 are passed through the nip 40 formed between the first embossing
roll 20 and the second embossing roll 30 where the plies are placed
into contact with each other and embossed. At this stage, it is
also common to join the webs together using conventional joining
methods such as an adhesive application system, but, as noted
above; other joining methods can be used. The combined web 100 is
then passed through the nip 75 between the first embossing roll 20
and the marrying roll 70. This step is often used to ensure that
the plies 80 and 90 of the web 100 are securely joined together
before the web 100 is directed to further processing steps or
winding.
[0045] It should be noted that with respect to any of the methods
described herein, the number of plies is not critical and can be
varied, as desired. Thus, it is within the realm of the present
invention to utilize methods and equipment that provide a final
roll paper product having a single ply, two plies, three plies,
four plies or any other number of plies suitable for the desired
end use. In each case, it is understood that one of skill in the
art would know to add or remove the equipment necessary to provide
and/or combine the different number of plies. Further, it should be
noted that the plies of a multi-ply roll paper product need not be
the same in make-up or other characteristics. Thus, the different
plies can be made from different materials, such as from different
fibers, different combinations of fibers, natural and synthetic
fibers or any other combination of materials making up the base
plies. Further, the resulting web 100 may include one or more plies
of a cellulosic web and/or one or more plies of a web made from
non-cellulose materials including polymeric materials, starch based
materials and any other natural or synthetic materials suitable for
forming fibrous webs. In addition, one or more of the plies may
include a nonwoven web, a woven web, a scrim, a film a foil or any
other generally planar sheet-like material. Further, one or more of
the plies can be embossed with a pattern that is different that one
or more of the other plies or can have no embossments at all.
[0046] In the deep-nested emboss process, one example of which is
shown in FIG. 5, the embossing protrusions 50 and 60 of the
embossing members (in this case embossing plates 21 and 31) engage
such that the distal end 110 of the first embossing protrusions 50
extend into the space 220 between the second embossing protrusions
60 of the second embossing roll 30 beyond the distal end 210 of the
second embossing protrusions 60. Accordingly, the distal ends 210
of the second embossing protrusions 60 should also extend into the
space 120 between the first embossing protrusions 50 of the first
embossing roll 20 beyond the distal end 110 of the first embossing
protrusions 50. The depth of the engagement E may vary depending on
the level of embossing desired on the final product and can be any
distance greater than zero. Typical deep-nested embodiments have a
engagement E greater than about 0.01 mm (0.000394 inches), greater
than about 0.05 mm (0.001969 inches), greater than about 1.0 mm
(0.03937 inches), greater than about 1.25 mm (0.049213 inches),
greater than about 1.5 mm (0.059055), greater than about 2.0 mm
(0.07874 inches), greater than about 3.0 mm (0.11811 inches),
greater than about 4.0 mm (0.15748 inches), greater than about 5.0
mm (0.19685 inches), between about 0.01 mm (0.000394 inches) and
about 5.0 mm (0.19685 inches) or any number within this range. It
should be noted that although the description in this paragraph
describes certain relationships between the embossing protrusions
50 and 60 disposed on embossing members that are embossing plates
21 and 31, the same engagement characteristics are applicable to
embossing protrusions 50 and 60 that are disposed on embossing
members that are not plates, but rather take on a different form,
such as, for example, the embossing rolls 20 and 30 shown in FIG.
1.
[0047] In certain embodiments, as shown, for example, in FIG. 5, at
least some of the first embossing protrusions 50 and/or the second
embossing protrusions 60, whether they are linear or discrete, may
have at least one transition region 130 between the face and the
sidewalls of the protrusion that has a radius of curvature of
curvature r. When a transition region is employed, the transition
region 130 is disposed between the distal end of the embossing
element and the sidewall of the embossing element. (As can be seen
in FIG. 5, the distal end of the first embossing element is labeled
110, while the sidewall of the first embossing element is labeled
115. Similarly, the distal end of the second embossing element is
labeled 210, while one of the sidewalls of the second embossing
element is labeled 215.) The radius of curvature of curvature r is
typically greater than about 0.075 mm (0.002953 inches). Other
embodiments have radii of greater than 0.1 mm (0.003937 inches),
greater than 0.25 mm (0.009843 inches), greater than about 0.5 mm
(0.019685 inches), between about 0.075 mm (0.002953 inches) and
about 0.5 mm (0.019685 inches) or any number within this range. The
radius of curvature of curvature r of any particular transition
region is typically less than about 1.8 mm (0.070866 inches). Other
embodiments may have embossing protrusions with transition regions
130 having radii of less than about 1.5 mm (0.059055 inches), less
than about 1.0 mm (0.03937 inches), between about 1.0 mm (0.03937
inches) and about 1.8 mm (0.070866 inches) or any number within the
range. (Although FIG. 5 shows an example of two intermeshing
embossing plates 21 and 31, the information set forth herein with
respect to the embossing protrusions 50 and 60 is applicable to any
type of embossing platform or mechanism from which the embossing
protrusions can extend, such as rolls, cylinders, plates and the
like.)
[0048] The "rounding" of the transition region 130 typically
results in a circular arc rounded transition region 130 from which
a radius of curvature of curvature is determined as a traditional
radius of curvature of the arc. The present invention, however,
also contemplates transition region configurations which
approximate an arc rounding by having the edge of the transition
region 130 removed by one or more straight line or irregular cut
lines. In such cases, the radius of curvature of curvature r is
determined by measuring the radius of curvature of a circular arc
that includes a portion which approximates the curve of the
transition region 130.
[0049] In other embodiments, at least a portion of the distal end
of one or more of the embossing protrusions other than the
transition regions 130 can be generally non-planar, including for
example, generally curved or rounded. Thus, the entire surface of
the embossing element spanning between the sidewalls 115 or 215 can
be non-planar, for example curved or rounded. The non-planar
surface can take on any shape, including, but not limited to smooth
curves or curves, as described above, that are actually a number of
straight line or irregular cuts to provide the non-planar surface.
One example of such an embossing element is the embossing element
62 shown in FIG. 5. Although not wishing to be bound by theory, it
is believed that rounding the transition regions 130 or any portion
of the distal ends of the embossing protrusions can provide the
resulting paper with embossments that are more blunt with fewer
rough edges. Thus, the resulting paper may be provided with a
smoother and/or softer look and feel.
[0050] One example of an embossed paper product is shown in FIG. 6.
The embossed fibrous structure 100 comprises one or more plies,
wherein at least one of the plies comprises a plurality of discrete
embossments 310 and a plurality of linear embossments 315 wherein
the difference in elevation between the apex of the discrete
embossments 310 and linear embossments 315 comprises an embossment
height 320. (Generally, the embossments take on a shape that is
similar to the embossing protrusions used to form the embossments,
thus, for the purposes of this application, the shapes and sizes of
the embossing protrusions described herein can also be used to
describe suitable embossments. However, it should be noted that the
shape of the embossments may not correspond exactly to the shape of
any particular embossing element or pattern of embossing
protrusions and thus, embossments of shapes and sizes different
than those described herein with regard to the embossing
protrusions are contemplated.) In some embodiments, the ply or
plies which are embossed are embossed in a deep-nested embossing
process such that the embossments exhibit an embossment height h of
at least about 650 .mu.m, at least about 800 .mu.m, at least about
900 .mu.m, at least about 1300 .mu.m, at least about 1550 .mu.m,
and at least about 1800 .mu.m. In one embodiment, the embossment
height is from about 650 .mu.m to about 4000 .mu.m. In another
embodiment, the embossment height is from about 800 .mu.m to about
3000 .mu.m. In another embodiment, the embossment height is from
about 900 .mu.m to about 1800 .mu.m. In another embodiment, the
embossment height is from about 1300 .mu.m to about 1550 .mu.m. The
embossment height h of the fibrous structure 100 is measured by the
Embossment Height Test method set forth below.
Measuring the Percentage of Unembossed Method
[0051] FIGS. 7 and 8 show one embodiment of a portion of an
exemplary embossing pattern 400 as it would appear on a paper web
comprising a plurality of discrete embossments 310. In one
embodiment the diameter of the emboss protrusions used to form the
discrete embossments 310 have a diameter D of from about 0.05
inches to about 0.20 inches. In another embodiment, the emboss
protrusions used to form the embossments 410 have a diameter D of
from about 0.06 inches (1.524 mm) to about 0.15 inches (3.81 mm).
In another embodiment, the emboss protrusions used to form the
emboss pattern 400 have a cross machine direction pitch P.sub.CD of
from about 0.1 inches (2.54 mm) to about 0.25 inches (6.35 mm). In
another embodiment, the emboss protrusions used to form the emboss
pattern 400 have a P.sub.CD of from about 0.15 inches (3.81 mm) to
about 0.2 inches (5.08 mm). In one embodiment, the emboss
protrusions used to form the emboss pattern 400 have a machine
direction pitch P.sub.MD of from about 0.1 inches (2.54 mm) to
about 0.3 inches (7.62 mm). In another embodiment, the emboss
protrusions used to form the emboss pattern 410 have a P.sub.MD of
from about 0.13 (3.302 mm) inches to about 0.18 inches (4.572
mm).
[0052] Because paper logs are normally cut in the machine direction
to form roll paper products, the density of embossments and
percentage of unembossed areas may be divided into tracts that are
segmented in the machine direction. To divide an emboss pattern 400
into one or more tracts, it is first necessary to identify
continuous unembossed elements. For the purpose of identifying
continuous unembossed elements, a region that comprises embossments
having similar spacing between embossments is said to not be a
continuous unembossed element, and will have a percent unembossed
(defined below) of zero. As used herein, "similar spacing between
embossments" means having less than a 30% variation between
P.sub.MD and/or P.sub.CD. In some embodiments, a continuous
unembossed element may be identified as any area having no
embossments where two or more embossments (having the same spacing
in the machine, and cross machine, direction as the embossments
around that area) may have been, but are not, located.
[0053] FIG. 8A shows a nonlimiting example of an emboss pattern 400
that, in one embodiment, may be tessellated with like emboss
patterns 400 to form a larger emboss pattern. As stated above, the
continuous unembossed areas are any areas having no embossments,
although two or more embossments (separated by similar spacing as
the surrounding embossments) could have been placed in that space.
In the exemplary emboss pattern 400, continuous unembossed areas
are hexagons and are delineated by broken lines 430 and referred to
as "trace lines." Tract lines 440 are drawn parallel to the machine
direction such that the tract lines 440 touch the outermost edges
or points in the cross machine direction of the continuous
unembossed areas 430. Each set of parallel tract lines forms a
tract. Sketch lines 410 are drawn around the emboss pattern 400 and
serve as boundaries for calculating percent unemboss. The area that
the embossed and unembossed areas occupy (which is bounded by the
sketch lines 410, trace lines 430, and tract lines 440) is measured
by calculating the total area for each figure that is bounded by a
set of lines sketch lines 410, trace lines 430 and tract lines 440
and has no lines sketch lines 410, trace lines 430, and tract lines
440 running through it.
[0054] For a tract that encompasses both embossed and unembossed
areas, the area of the unembossed area is divided by the sum of the
embossed and unembossed areas for that tract to provide the percent
unembossed. For a tract that has no unembossed areas then the
percent unembossed is 0. Repeat this step for each tract. If two
adjacent tracts have the same percentage unembossed then these
tracts can be merged into one tract. In an embodiment, the tracts
with the lowest percent unembossed are the first tracts. In an
embodiment, the tracts with the highest percent unembossed are the
second tracts. In other words, the second tracts 442 are tracts
that have a higher percent unembossed than the first tracts 441.
Any tract with an intermediate percent unembossed are neither first
nor second tracts. In one embodiment, the first tract has a percent
unembossed from about 0% to about 40%. In another embodiment, the
first tract has a percent unembossed from about 0% to about 25%. If
there is only one tract, then there the log may be cut anywhere
along the pattern.
[0055] Referring to FIG. 8B, the first tracts 441 are any tracts of
the pattern which have the lowest percentage unembossed and the
second tracts 442 are any tracts of the pattern which have the
highest percentage unembossed. In the exemplary embodiment shown in
FIG. 8B the first tracts 441 have a percent unembossed of 0 and the
second tracts 442 have a percent unembossed of about 23.8%. An
ideal cut line 443 is a line in a first tract that is furthest from
the adjacent second tracts. In one embodiment an ideal cut line 443
bisects a first tract 441 along the cross machine direction width
W.sub.CD of the first tract. In certain embodiments a cut may be
made between from about 1/4 to about 3/4 of the W.sub.CD of the
first tract. In another embodiment a cut is made between from about
1/3 to about 2/3 of the W.sub.CD of the first tract. In an
embodiment the second tracts 442 have the highest percentage
unembossed. In one embodiment, the first tracts 441 have a higher
percent unembossed than the second tracts 442. The relationship
between the percent unembossed of one first tract and one second
tract may be described by a "Unembossed to Emboss factor", U/E,
which is simply the exponential of the percent unembossed of the
first tract divided by the percent unembossed of the second tract
as described below:
U / E = Exp [ PU 1 PU 2 ] ##EQU00001##
Where:
[0056] U/E is the Unemboss to Emboss factor [0057] PU1 is the
percent unembossed of one first tract [0058] PU2 is the percent
unembossed of one second tract
[0059] In another embodiment U/E is from about 1 to about 2.3. In
another embodiment the U/E is from about 1.5 to about 2.
Cutting the Paper Logs
[0060] Methods for cutting a paper log are well known in the art.
During a typical papermaking process a paper log roll is processed
and then cut into smaller rolls for retail sale. An exemplary
process for cutting paper logs is shown in U.S. Pat. No.
5,038,647.
[0061] When a highly embossed paper web log is cut into smaller
rolls for retail sale the top and bottom surfaces of the rolls, or
edges, may exhibit spaces or gaps between the plies that result
from the embossing process. This spacing effect is referred to
herein as "gapping." Without being limited by theory it is thought
that cutting a paper log within tracts that have a low percent
embossments (i.e., having a large number of unembossed areas)
causes the differences in height between embossments and unembossed
areas to become highly visually apparent on the edges of the
resultant paper rolls in the form of gapping.
[0062] FIGS. 9A and 9B show an exemplary embodiment of a paper log
500 having the exemplary embossing pattern 400. In one embodiment
the log is wound around a core 510. The log can be cut to smaller
rolls of any length. The length of the log that is to be cut may be
any length. In one embodiment, the length of the log L.sub.log
prior to cutting is from about 80 inches to about 120 inches. In
another embodiment, the length of the log to be cut is from about
95 inches to about 105 inches.
[0063] FIGS. 10A and 10B show an exemplary embodiment of a paper
roll 600 that has been cut from the paper log 500 of FIGS. 9A and
9B having the exemplary embossing pattern 400 along lines 550-550
and 560-560 shown in FIGS. 9A and 9B. The paper roll 600 has a
surface 610 on which the embossing pattern 400 is disposed and an
edge 620 on each of the axial surfaces. In one embodiment, the
paper log 500 has been cut such that an edge 620 of the paper roll
600 is tangential to one or more first tracts 441. In another
embodiment, the paper log 500 has been cut such that the edge 620
of the paper roll 600 is tangential from about 1/4 to about 3/4 of
the cross machine direction width W.sub.CD of one or more first
tracts 441. In another embodiment, the paper log 500 has been cut
such that the machine direction edge 620 of the paper roll 600 is
tangential from about 1/3 to about 2/3 of the W.sub.CD of one or
more first tracts. In another embodiment, the paper log 500 has
been cut such that the machine direction edge 620 of the paper roll
600 is tangential from about the midpoint of the W.sub.CD of one or
more first tracts 441. In one embodiment, the machine direction
edge of the roll exhibits small spaces or gaps 630. The length of
the rolls L.sub.roll that a paper log may be cut into can be any
length that is less than the length of the original paper log. In
one embodiment, the rolls are from about 3 inches to about 13
inches long. In another embodiment the rolls are from about 4
inches to about 11 inches long.
Embossment Height Test Method
[0064] Embossment height is measured using an Optical 3D Measuring
System MikroCAD compact for paper measurement instrument (the "GFM
MikroCAD optical profiler instrument") and ODSCAD Version 4.0
software available from GFMesstechnik GmbH, Warthestra.beta.e E21,
D14513 Teltow, Berlin, Germany. The GFM MikroCAD optical profiler
instrument includes a compact optical measuring sensor based on
digital micro-mirror projection, consisting of the following
components: [0065] A) A DMD projector with 1024.times.768 direct
digital controlled micro-mirrors. [0066] B) CCD camera with high
resolution (1300.times.1000 pixels). [0067] C) Projection optics
adapted to a measuring area of at least 27.times.22 mm. [0068] D)
Recording optics adapted to a measuring area of at least
27.times.22 mm; a table tripod based on a small hard stone plate; a
cold-light source; a measuring, control, and evaluation computer;
measuring, control, and evaluation software, and adjusting probes
for lateral (X-Y) and vertical (Z) calibration. [0069] E) Schott
KL1500 LCD cold light source. [0070] F) Table and tripod based on a
small hard stone plate. [0071] G) Measuring, control and evaluation
computer. [0072] H) Measuring, control and evaluation software
ODSCAD 4.0. [0073] I) Adjusting probes for lateral (x-y) and
vertical (z) calibration.
[0074] The GFM MikroCAD optical profiler system measures the height
of a sample using the digital micro-mirror pattern projection
technique. The result of the analysis is a map of surface height
(Z) versus X-Y displacement. The system should provide a field of
view of 27.times.22 mm with a resolution of 21 .mu.m. The height
resolution is set to between 0.10 .mu.m and 1.00 .mu.m. The height
range is 64,000 times the resolution. To measure a fibrous
structure sample, the following steps are utilized: [0075] 1. Turn
on the cold-light source. The settings on the cold-light source are
set to provide a reading of at least 2,800 k on the display. [0076]
2. Turn on the computer, monitor, and printer, and open the
software. [0077] 3. Select "Start Measurement" icon from the ODSCAD
task bar and then click the "Live Image" button. [0078] 4. Obtain a
fibrous structure sample that is larger than the equipment field of
view and conditioned at a temperature of 73.degree. F..+-.2.degree.
F. (about 23.degree. C..+-.1.degree. C.) and a relative humidity of
50%+2% for 2 hours. Place the sample under the projection head.
Position the projection head to be normal to the sample surface.
[0079] 5. Adjust the distance between the sample and the projection
head for best focus in the following manner. Turn on the "Show
Cross" button. A blue cross should appear on the screen. Click the
"Pattern" button repeatedly to project one of the several focusing
patterns to aid in achieving the best focus. Select a pattern with
a cross hair such as the one with the square. Adjust the focus
control until the cross hair is aligned with the blue "cross" on
the screen. [0080] 6. Adjust image brightness by changing the
aperture on the lens through the hole in the side of the projector
head and/or altering the camera gains setting on the screen. When
the illumination is optimum, the red circle at the bottom of the
screen labeled "I.O." will turn green. [0081] 7. Select technical
surface/rough measurement type. [0082] 8. Click on the "Measure"
button. When keeping the sample still in order to avoid blurring of
the captured image. [0083] 9. To move the data into the analysis
portion of the software, click on the clipboard/man icon.
[0084] Click on the icon "Draw Cutting Lines." On the captured
image, "draw" six cutting lines (randomly selected) that extend
from the center of a positive embossment through the center of a
negative embossment to the center of another positive embossment.
Click on the icon "Show Sectional Line Diagram." Make sure active
line is set to line 1. Move the cross-hairs to the lowest point on
the left side of the computer screen image and click the mouse.
Then move the cross-hairs to the lowest point on the right side of
the computer screen image on the current line and click the mouse.
Click on the "Align" button by marked point's icon. Click the mouse
on the lowest point on this line and then click the mouse on the
highest point of the line. Click the "Vertical" distance icon.
Record the distance measurement. Increase the active line to the
next line, and repeat the previous steps until all six lines have
been measured. Perform this task for four sheets equally spaced
throughout the Finished Product Roll, and four finished product
rolls for a total of 16 sheets or 96 recorded height values. Take
the average of all recorded numbers and report in mm, or .mu.m, as
desired. This number is the embossment height.
EXAMPLE
Cut Along a Second Tract
[0085] One fibrous structure useful in achieving the roll paper
product of the present invention is the through-air-dried (TAD),
differential density structure described in U.S. Pat. No.
4,528,239. Such a structure may be formed by the following
process.
[0086] A Fourdrinier, through-air-dried papermaking machine is used
in the practice of this invention. A slurry of papermaking fibers
is pumped to the headbox at a consistency of about 0.15%. The
slurry consists of about 55% Northern Softwood Kraft fibers, about
30% unrefined Eucalyptus fibers and about 15% repulped product
broke. The fiber slurry contains a cationic
polyamine-epichlorohydrin wet burst strength resin at a
concentration of about 10.0 kg per metric ton of dry fiber, and
carboxymethyl cellulose at a concentration of about 3.5 kg per
metric ton of dry fiber.
[0087] Dewatering occurs through the Fourdrinier wire and is
assisted by vacuum boxes. The wire is of a configuration having
41.7 machine direction and 42.5 cross machine direction filaments
per cm, such as that available from Asten Johnson known as a "786
wire".
[0088] The embryonic wet web is transferred from the Fourdrinier
wire to a TAD carrier fabric. The sheet side of the carrier fabric
consists of a continuous, patterned network of photopolymer resin,
the pattern containing about 90 deflection conduits per inch. The
deflection conduits are arranged in an amorphous configuration, and
the polymer network covers about 25% of the surface area of the
carrier fabric.
[0089] The consistency of the web is about 65% after the action of
the TAD dryers operating about a 254.degree. C., before transfer
onto the Yankee dryer. An aqueous solution of creping adhesive
consisting of animal glue and polyvinyl alcohol is applied to the
Yankee surface by spray applicators at a rate of about 0.66 kg per
metric ton of production. The fiber consistency is increased to an
estimated 95.5% before creping the web with a doctor blade. The
Yankee dryer is operated at about 157.degree. C., and Yankee hoods
are operated at about 120.degree. C.
[0090] The dry, creped web is passed between two calendar rolls and
rolled on a reel. The resulting paper has a basis weight of about
23 grams per square meter (gsm) and has a MD stretch of about 21%
and a CD stretch of about 9%.
[0091] The paper described above is then subjected to the
deep-nested embossing process of this invention. Two emboss rolls
are engraved with complimentary, nesting embossing protrusions
shown in FIGS. 1-6. The rolls are mounted in the apparatus with
their respective axes being generally parallel to one another. The
rolls are engraved such that the protrusions are in a non-random
overall pattern having a multiple repeating pattern of the pattern
shown in FIG. 8. The discrete embossing protrusions are
frustaconical in shape, with a face (top or distal--i.e. away from
the roll from which they protrude) diameter of about 2.79 mm and a
floor (bottom or proximal--i.e. closest to the surface of the roll
from which they protrude) diameter of about 4.12 mm. The linear
protrusions have a width similar to that of the discrete embossing
protrusions of about 2.79 mm. The height of the embossing
protrusions on each roll is from about 2.718 mm to about 2.845 mm.
The planar projected area of each embossing pattern single pattern
unit is about 25 cm.sup.2. The paper described above is fed through
the engaged gap at a speed between 300 and 400 meters per minute.
The resulting paper has an embossment height of greater than about
1000 .mu.m.
[0092] The embossment pattern of the present example invention is
that shown in FIGS. 8A and 8B. The first tracts have a percentage
unembossed of 0. The second tracts have a percentage unembossed of
about 23.8%. The paper log is cut along the second tract and yields
a product that has machine direction edges that are highly gapped
as shown in FIG. 11A.
EXAMPLE
Cut Along a First Tract
[0093] In another embodiment of the roll paper product, the cutting
process of Example 1 is modified such that the paper of Example 1
is cut within a first tract. The resulting paper yields a product
with machine direction edges having relatively little gapping as
shown in FIG. 11B.
[0094] It is noted that terms like "specifically," "preferably,"
"typically", "generally", and "often" are not utilized herein to
limit the scope of the claimed invention or to imply that certain
features are critical, essential, or even important to the
structure or function of the claimed invention. Rather, these terms
are merely intended to highlight alternative or additional features
that may or may not be utilized in a particular embodiment of the
present invention. It is also noted that terms like "substantially"
and "about" are utilized herein to represent the inherent degree of
uncertainty that may be attributed to any quantitative comparison,
value, measurement, or other representation.
[0095] 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".
[0096] All documents cited in the Detailed Description of the
Invention are, in relevant part, incorporated herein by reference;
the citation of any document is not to be construed as an admission
that it is prior art with respect to the present invention. To the
extent that any meaning or definition of a term in this written
document conflicts with any meaning or definition of the term in a
document incorporated by reference, the meaning or definition
assigned to the term in this written document shall govern.
[0097] 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.
* * * * *