Note: Descriptions are shown in the official language in which they were submitted.
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WET-PRESSED TISSUE AND TOWEL PRODUCTS WITH ELEVATED CD
STRETCH AND LOW TENSILE RATIOS MADE WITH A HIGH SOLIDS
FABRIC CREPE PROCESS
This application is directed, in part, to a process wherein a web
is compactively dewatered, creped into a creping fabric and dried wherein
processing is controlled to produce products with high Cross-machine direction
(CD) stretch
and low tensile ratios.
Background
Methods of making paper tissue, towel, and the like are well known,
including various features such as Yankee drying, throughdrying, fabric
creping,
dry creping, wet creping and so forth. Conventional wet pressing processes
have
certain advantages over conventional through-air drying processes including:
(1)
lower energy costs associated with the mechanical removal of water rather than
transpiration drying with hot air; and (2) higher production speeds which are
more
readily achieved with processes which utilize wet pressing to form a web. On
the
other hand, through-air drying processing has been widely adopted for new
capital investment, particularly for the production of soft, bulky, premium
quality
tissue and towel products.
Fabric creping has been employed in connection with papermaking
processes which include mechanical or compactive dewatering of the paper web
30
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as a means to influence product properties. See United States Patent Nos.
4,689,119 and 4,551,199 of Weldon; 4,849,054 and 4,834,838 of Klowak; and
6,287,426 of Edwards et al. Operation of fabric creping processes has been
hampered by the difficulty of effectively transferring a web of high or
intermediate consistency to a dryer. Note also United States Patent No.
6,350,349
to Hermans et al. which discloses wet transfer of a web from a rotating
transfer
surface to a fabric. Further patents relating to fabric creping more generally
include the following: 4,834,838; 4,482,429 4,445,638 as well as 4,440,597 to
Wells et al.
In connection with papermaking processes, fabric molding has also been
employed as a means to provide texture and bulk. In this respect, there is
seen in
United States Patent No. 6,610,173 to Lindsey et al. a method for imprinting a
paper web during a wet pressing event which results in asymmetrical
protrusions
corresponding to the deflection conduits of a deflection member. The '173
patent
reports that a differential velocity transfer during a pressing event serves
to
improve the molding and imprinting of a web with a deflection member. The
tissue webs produced are reported as having particular sets of physical and
geometrical properties, such as a pattern densified network and a repeating
pattern
of protrusions having asymmetrical structures. With respect to wet-molding of
a
web using textured fabrics, see, also, the following United, States Patents:
6,017,417 and 5,672,248 both to Wendt et al.; 5,508,818 and 5,510,002 to
Hennans et al. and 4,637, 859 to Trokhan. With respect to the use of fabrics
used
to impart texture to a mostly dry sheet, see United States Patent No.
6,585,855 to
Drew et al., as well as United States Publication No. US 2003/00064.
Throughdried, creped products are disclosed in the following patents:
United States Patent No. 3,994,771 to Morgan, Jr. et al.; United States Patent
No.
4,102,737 to Morton; and United States Patent No. 4,529,480 to Trokhan. The
processes described in these patents comprise, very generally, forming a web
on a
foraminous support, thermally pre-drying the web, applying the web to a Yankee
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dryer with a nip defined, in part, by an impression fabric, and creping the
product
from the Yankee dryer. A relatively permeable web is typically required,
making
it difficult to employ recycle furnish at levels which may be desired.
Transfer to
the Yankee typically takes place at web consistencies of from about 60% to
about
70%; although in some processes the transfer occurs at much higher
consistencies,
sometimes even approaching air-dry.
As noted in the above, throughdried products tend to exhibit enhanced
bulk and softness; however, thermal dewatering with hot air tends to be energy
intensive. Wet-press operations wherein the webs are mechanically dewatered
are
preferable from an energy perspective and are more readily applied to
furnishes
containing recycle fiber which tends to form webs with less permeability than
virgin fiber. Many improvements relate to increasing the bulk and absorbency
of
compactively dewatered products which are typically dewatered, in part, with a
papermaking felt.
Despite advances in the art, previously known wet press processes have
not produced the highly absorbent webs with preferred physical properties
especially elevated CD stretch at relatively low MD/CD tensile ratios as are
sought after for use in premium tissue and towel products.
In accordance with the present invention, the absorbency, bulk and stretch
of a wet-pressed web can be vastly improved by wet fabric creping a web and
rearranging the fiber on a creping fabric, while preserving the high speed,
thermal
efficiency, and furnish tolerance to recycle fiber of conventional wet press
processes
Summary of the Invention
There is thus provided in a first aspect of the invention an absorbent sheet
of cellulosic fibers including a mixture of hardwood fibers and softwood
fibers
arranged in a reticulum having: (i) a plurality of pileated fiber enriched
regions of
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relatively high local basis weight interconnected by way of (ii) a plurality
of lower
local basis weight linking regions. The fiber orientation of the linking
regions is
biased along the direction between pileated regions interconnected thereby.
The
relative basis weight, degree of pileation, hardwood to softwood ratio, fiber
length
distribution, fiber orientation, and geometry of the reticulum are controlled
such
that the sheet exhibits a percent CD stretch of at least about 2.75 times the
dry
tensile ratio of the sheet. In one preferred embodiment the sheet exhibits a
void
volume of at least about 5 g/g, a CD stretch of at least about 5 percent and a
MD/CD tensile ratio of less than about 1.75. In another preferred embodiment
the
MD/CD tensile ratio is less than about 1.5. In another preferred embodiment
the
= sheet has an absorbency of at least about 5 g/g, a CD stretch of at least
about 10
percent and a MD/CD tensile ratio of less than about 2.5. In a still further
preferred embodiment the sheet exhibits an absorbency of at least about 5 g/g,
a
CD stretch of at least about 15 percent and a MD/CD tensile ratio of less than
about 3.5. A CD stretch of at least about 20 percent and a MD/CD tensile ratio
of
less than about 5 is believed achievable in accordance with the present
invention.
As will be seen from the data which follows, a percent CD stretch of at
least about 3, 3.25 or 3.5 times the dry tensile ratio is readily achieved in
accordance with the present invention.
In general, a percent CD stretch of at least about 4 and a dry tensile ratio
of
from about 0.4 to about 4 are typical of products of the invention.
Preferably, the
products have a CD stretch of least about 5 or 6. In some cases a CD stretch
of at
least about 8 or at least about 10 is preferred.
The inventive products typically have a void volume of at least about 5 or
6 g/g. Void volumes of at least about 7 g/g, 8 g/g, 9 g/g or 10 g/g are
likewise
typical.
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The inventive sheet may consist predominantly (more than 50%) of
hardwood fiber or softwood fiber. Typically the sheet includes a mixture of
these
two fibers.
5 In another aspect of the invention there is provided a method of
making a
cellulosic web for tissue or towel products including the steps of: (a)
preparing an
aqueous cellulosic papermaking furnish; (b) providing the papermaking furnish
to
a forming fabric as a jet issuing from a head box at a jet speed; (c)
compactively
dewatering the papermaking furnish to form a nascent web having an apparently
random distribution of papermaking fiber; (d) applying the dewatered web
having
an apparently random fiber distribution to a translating transfer surface
moving at
a first speed; (e) belt creping the web from the transfer surface at a
consistency of
from about 30 to about 60 percent utilizing a patterned creping belt, the
creping
step occurring under pressure in a belt creping nip defined between the
transfer
surface of the creping belt wherein the belt is traveling at a second speed
slower
than the speed of said transfer surface. The belt pattern, nip parameters,
velocity
delta and web consistency are selected such that the web is creped from the
transfer surface and redistributed on the creping belt to form a web with a
reticulum having a plurality of interconnected regions of different local
basis
weights including at least (i) a plurality of fiber enriched regions of
relatively high
local basis weight, interconnected by way of (ii) a plurality of lower local
basis
weight regions. The web is then dried. It will be seen that the hardwood to
softwood ratio, fiber length distribution, overall crepe, jet speed, drying
and belt
creping steps are controlled and the creping belt pattern is selected such
that the
web is characterized in that it has a percent CD stretch which is at least
about 2.75
times the dry tensile ratio of the web. These parameters are also selected
such that
the properties noted above in connection with the inventive products are
achieved
in various embodiments of the invention.
The inventive process may be practiced with predominantly hardwood
fiber for producing base sheet for tissue manufacture or the inventive process
may
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be practiced with a furnish consisting predominantly of softwood fiber when it
is
desired to make towel. It will be appreciated by one of skill in the art that
other
additives are selected as so desired.
It has been found in accordance with the present invention that the webs
having a local variation in basis weight are preferably calendered between
steel
calender rolls when calendering is desirable.
The belt creped web of the invention is typically characterized in that the
fibers of the fiber enriched regions are biased in the cross direction as Will
be
appreciated from the attached photomicrographs.
Generally the process is operated at a fabric crepe of from about 10 to
about 100 percent. Preferred embodiments include those wherein the process is
operated at a fabric crepe of at least about 40, 60, 80 or 100 percent or
more. The
inventive process may be operated at a fabric crepe of 125 percent or more.
The process of the present invention is exceedingly furnish tolerant, and
can be operated with large amounts of secondary fiber if so desired.
Still further features and advantages of the present invention will become
apparent from the discussion which follows.
Brief Description of Drawings
The invention is described in detail below with reference to the Figures,
wherein:
Figure 1 is a photomicrograph (120X) in section along the machine
direction of a fiber enriched region of a fabric creped sheet;
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Figure 2 is a plot of MD/CD dry tensile ratio versus jet/wire velocity delta
in feet per minute;
Figure 3 is a photomicrograph (10X) of the fabric side of a fabric creped
web;
Figure 4 is a schematic diagram illustrating a paper machine which may
be used to produce the products and practice the process of the present
invention;
Figures 5 and 6 are plots of CD stretch versus MD/CD tensile ratio for 13
lb sheet produced with various fabrics and crepe ratios;
Figures 7 through 9 are plots of CD stretch versus dry tensile ratio for
various 24 lb sheets of the invention; and
Figure 10 is a plot of caliper reduction versus calender load for various
combinations of steel and rubber calender rolls.
Detailed Description
Terminology used herein is given its ordinary meaning with the exemplary
definitions set forth immediately below.
Absorbency of the inventive products (SAT) is measured with a simple
absorbency tester. The simple absorbency tester is a particularly useful
apparatus
for measuring the hydrophilicity and absorbency properties of a sample of
tissue,
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napkins, or towel. In this test a sample of tissue, napkins, or towel 2.0
inches in
diameter is mounted between a top flat plastic cover and a bottom grooved
sample
plate. The tissue, napkin, or towel sample disc is held in place by a 1/8 inch
wide
circumference flange area. The sample is not compressed by the holder. De-
ionized water at 73 F is introduced to the sample at the center of the bottom
sample plate through a 1 mm. diameter conduit. This water is at a hydrostatic
head
of minus 5 mm. Flow is initiated by a pulse introduced at the start of the
measurement by the instrument mechanism. Water is thus imbibed by the tissue,
napkin, or towel sample from this central entrance point radially outward by
capillary action. When the rate of water imbibation decreases below 0.005 gm
water per 5 seconds, the test is terminated. The amount of water removed from
the
reservoir and absorbed by the sample is weighed and reported as grams of water
per square meter of sample unless otherwise indicated. In practice, an M/K
Systems Inc. Gravimetric Absorbency Testing System is used. This is a
commercial system obtainable from M/K Systems Inc., 12 Garden Street,
Danvers, Mass, 01923. WAC or water absorbent capacity also referred to as SAT
is actually determined by the instrument itself. WAC is defined as the point
where
the weight versus time graph has a "zero" slope, i.e., the sample has stopped
absorbing. The termination criteria for a test are expressed in maximum change
in
water weight absorbed over a fixed time period. This is basically an estimate
of
zero slope on the weight versus time graph. The program uses a change of 0.005
g over a 5 second time interval as termination criteria; unless "Slow Sat" is
specified in which case the cut off criteria is 1 mg in 20 seconds.
Throughout this specification and claims, when we refer to a nascent web
having an apparently random distribution of fiber orientation (or use like
terminology), we are referring to the distribution of fiber orientation that
results
when known forming techniques are used for depositing a furnish on the forming
fabric. When examined microscopically, the fibers give the appearance of being
randomly oriented even though, depending on the jet to wire speed, there may
be a
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significant bias toward machine direction orientation making the machine
direction tensile strength of the web exceed the cross-direction tensile
strength.
Unless otherwise specified, "basis weight", BWT, bwt and so forth refers
to the weight of a 3000 square foot ream of product. Consistency refers to
percent
solids of a nascent web, for example, calculated on a bone dry basis. "Air
dry"
means including residual moisture, by convention up to about 10 percent
moisture
for pulp and up to about 6% for paper. A nascent web having 50 percent water
and 50 percent bone dry pulp has a consistency of 50 percent.
The term "cellulosic", "cellulosic sheet" and the like is meant to include
any product incorporating papermaking fiber having cellulose as a major
constituent. "Papermaking fibers" include virgin pulps or recycle (secondary)
cellulosic fibers or fiber mixes comprising cellulosic fibers. Fibers suitable
for
making the webs of this invention include: nonwood fibers, such as cotton
fibers
or cotton derivatives, abaca, kenaf, sabai grass, flax, esparto grass, straw,
jute
hemp, bagasse, milkweed floss fibers, and pineapple leaf fibers; and wood
fibers
such as those obtained from deciduous and coniferous trees, including softwood
fibers, such as northern and southern softwood kraft fibers; hardwood fibers,
such
as eucalyptus, maple, birch, aspen, or the like. Papermaking fibers can be
liberated from their source material by any one of a number of chemical
pulping
processes familiar to one experienced in the art including sulfate, sulfite,
polysulfide, soda pulping, etc. The pulp can be bleached if desired by
chemical
means including the use of chlorine, chlorine dioxide, oxygen and so forth.
The
products of the present invention may comprise a blend of conventional fibers
(whether derived from virgin pulp or recycle sources) and high coarseness
lignin-
rich tubular fibers, such as bleached chemical thermomechanical pulp (BCTMP).
"Furnishes" and like terminology refers to aqueous compositions including
papermaking fibers, wet strength resins, debonders and the like for making
paper
products.
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As used herein, the term compactively dewatering the web or furnish
refers to mechanical dewatering by wet pressing on a dewatering felt, for
example,
in some embodiments by use of mechanical pressure applied continuously over
the web surface as in a nip between a press roll and a press shoe wherein the
web
5 is in contact with a papermaking felt. The terminology "compactively
dewatering" is used to distinguish processes wherein the initial dewatering of
the
web is carried out largely by thermal means as is the case, for example, in
United
States Patent No. 4,529,480 to Trolchan and United States Patent No. 5,607,551
to
Farrington et al. noted above. Compactively dewatering a web thus refers, for
10 example, to removing water from a nascent web having a consistency of
less than
30 percent or so by application of pressure thereto and/or increasing the
consistency of the web by about 15 percent or more by application of pressure
thereto.
"Fabric side" and like terminology refers to the side of the web which is in
contact with the creping and drying fabric. "Dryer side" or the like is the
side of
the web opposite the fabric side of the web.
Fpm refers to feet per minute while consistency refers to the weight
percent fiber of the web.
MD means machine direction and CD means cross-machine direction.
Nip parameters include, without limitation, nip pressure, nip length,
backing roll hardness, fabric approach angle, fabric takeaway angle,
uniformity,
and velocity delta between surfaces of the nip.
Nip length means the length over which the nip surfaces are in contact.
"On line" and like terminology refers to a process step performed without
removing the web from the papermachine in which the web is produced. A web is
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drawn or calendered on line when it is drawn or calendered without being
severed
prior to wind-up.
A translating transfer surface refers to the surface from which the web is
creped into the creping fabric. The translating transfer surface may be the
surface
of a rotating drum as described hereafter, or may be the surface of a
continuous
smooth moving belt or another moving fabric which may have surface texture and
so forth. The translating transfer surface needs to support the web and
facilitate
the high solids creping as will be appreciated from the discussion which
follows.
Calipers and or bulk reported herein may be 1, 4 or 8 sheet calipers. The
sheets are stacked and the caliper measurement taken about the central portion
of
the stack. Preferably, the test samples are conditioned in an atmosphere of
230
1.0 C (73.4 1.8 F) at 50% relative humidity for at least about 2 hours and
then
measured with a Thwing-Albert Model 89-II-JR or Progage Electronic Thickness
Tester with 2-in (50.8-mm) diameter anvils, 539 10 grams dead weight load,
and
0.231 in./sec descent rate. For finished product testing, each sheet of
product to
be tested must have the same number of plies as the product is sold. For
testing in
general, eight sheets are selected and stacked together. For napkin testing,
napkins are enfolded prior to stacking. For basesheet testing off of winders,
each
sheet to be tested must have the same number of plies as produced off the
winder.
For basesheet testing off of the papermachine reel, single plies must be used.
Sheets are stacked together aligned in the MD. On custom embossed or printed
product, try to avoid taking measurements in these areas if at all possible.
Bulk
may also be expressed in units of volume/weight by dividing caliper by basis
weight.
Dry tensile strengths (MD and CD), stretch, ratios thereof, break modulus,
stress and strain are measured with a standard Instron*test device or other
suitable
elongation tensile tester which may be configured in various ways, typically
using
*Trade-mark
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3 or 1 inch wide strips of tissue or towel, conditioned at 50% relative
humidity
and 23 C (73.4), with the tensile test run at a crosshead speed of 2 in/min.
Tensile ratios are simply ratios of the values determined by way of the
foregoing methods. Tensile ratio refers to the MD/CD dry tensile ratio unless
otherwise stated. Unless otherwise specified, a tensile property is a dry
sheet
property. Tensile strength is sometimes referred to simply as tensile. Unless
otherwise specified, break tensile strength, stretch and so forth are reported
herein.
"Fabric crepe ratio" is an expression of the speed differential between the
creping fabric and the forming wire and typically calculated as the ratio of
the web
speed immediately before creping and the web speed immediately following
creping, because the forming wire and transfer surface are typically, but not
necessarily, operated at the same speed:
Fabric crepe ratio ---- transfer cylinder speed creping fabric speed
Fabric crepe can also be expressed as a percentage calculated as:
Fabric crepe, percent, = Fabric crepe ratio ¨ 1 x 100%
Line crepe (sometimes referred to as overall crepe), reel crepe and so forth
are similarly calculated as discussed below.
PLI or ph i means pounds force per linear inch.
Predominantly means more than about 50%, typically by weight; bone dry
basis when referring to fiber.
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Pusey and Jones (P+J) hardness (indentation) sometimes referred to as P+J
is measured in accordance with ASTM D 531, and refers to the indentation
number (standard specimen and conditions).
Velocity delta means a difference in linear speed.
The void volume and /or void volume ratio as referred to hereafter, are
determined by saturating a sheet with a nonpolar POROFIL liquid and
measuring the amount of liquid absorbed. The volume of liquid absorbed is
equivalent to the void volume within the sheet structure. The percent weight
increase (PWI) is expressed as grams of liquid absorbed per gram of fiber in
the
sheet structure times 100, as noted hereinafter. More specifically, for each
single-
ply sheet sample to be tested, select 8 sheets and cut out a 1 inch by 1 inch
square
(1 inch in the machine direction and 1 inch in the cross-machine direction).
For
multi-ply product samples, each ply is measured as a separate entity. Multiple
samples should be separated into individual single plies and 8 sheets from
each
ply position used for testing. Weigh and record the dry weight of each test
specimen to the nearest 0.0001 gram. Place the specimen in a dish containing
POROFIL liquid having a specific gravity of 1.875 grams per cubic centimeter,
available from Coulter Electronics Ltd., Northwell Drive, Luton, Beds, England
(Part No. 9902458.) After 10 seconds, grasp the specimen at the very edge (1-2
Millimeters in) of one corner with tweezers and remove from the liquid. Hold
the
specimen with that corner uppermost and allow excess liquid to drip for 30
seconds. Lightly dab (less than 1/2 second contact) the lower corner of the
specimen on #4 filter paper (Whatman Lt., Maidstone, England) in order to
remove any excess of the last partial drop. Immediately weigh the specimen,
within 10 seconds, recording the weight to the nearest 0.0001 gram. The PWI
for
each specimen, expressed as grams of POROFIL per gram of fiber, is calculated
as follows:
PWI = [(W2-W1)1W1] X 100%
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wherein
"WI" is the dry weight of the specimen, in grams; and
"W2" is the wet weight of the specimen, in grams.
The PWI for all eight individual specimens is determined as described
above and the average of the eight specimens is the PWI for the sample.
The void volume ratio is calculated by dividing the PWI by 1.9 (density of
fluid) to express the ratio as a percentage, whereas the void volume (gms/gm)
is
simply the weight increase ratio; that is, PWI divided by 100.
According to the present invention, an absorbent paper web is made by
dispersing papermaking fibers into aqueous furnish (slurry) and depositing the
aqueous furnish onto the forming wire of a pap ermaking machine, typically by
way of a jet issuing from a headbox. Any suitable forming scheme might be
used.
For example, an extensive but non-exhaustive list in addition to Fourdrinier
formers includes a crescent former, a C-wrap twin wire former, an S-wrap twin
wire former, or a suction breast roll former. The forming fabric can be any
suitable foraminous member including single layer fabrics, double layer
fabrics,
triple layer fabrics, photopolymer fabrics, and the like. Non-exhaustive
background art in the forming fabric area includes United States Patent Nos.
4,157,276; 4,605,585; 4,161,195; 3,545,705; 3,549,742; 3,858,623; 4,041,989;
4,071,050; 4,112,982; 4,149,571; 4,182,381; 4,184,519; 4,314,589; 4,359,069;
4,376,455; 4,379,735; 4,453,573; 4,564,052; 4,592,395; 4,611,639; 4,640,741;
4,709,732; 4,759,391; 4,759,976; 4,942,077; 4,967,085; 4,998,568; 5,016,678;
5,054,525; 5,066,532; 5,098,519; 5,103,874; 5,114,777; 5,167,261; 5,199,261;
5,199,467; 5,211,815; 5,219,004; 5,245,025; 5,277,761; 5,328,565; and
5,379,808.
One forming
fabric particularly useful with the present invention is Voith*Fabrics Forming
Fabric 2164 made by Voith Fabrics Corporation, Shreveport, LA.
*Trade-mark
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Foam-forming of the aqueous furnish on a forming wire or fabric may be
employed as a means for controlling the permeability or void volume of the
sheet
upon fabric-creping. Foam-forming techniques are disclosed in United States
5 Patent No. 4,543,156 and Canadian Patent No. 2,053,505,
The foamed fiber furnish is made up from
an aqueous slun-y of fibers mixed with a foamed liquid carrier just prior to
its
introduction to the headbox. The pulp slurry supplied to the system has a
consistency in the range of from about 0.5 to about 7 weight percent fibers,
10 preferably in the range of from about 2.5 to about 4.5 weight percent.
The pulp
slurry is added to a foamed liquid comprising water, air and surfactant
containing
50 to 80 percent air by volume forming a foamed fiber furnish having a
consistency in the range of from about 0.1 to about 3 weight percent fiber by
simple mixing from natural turbulence and mixing inherent in the process
15 elements. The addition of the pulp as a low consistency slurry results
in excess
foamed liquid recovered from the forming wires. The excess foamed liquid is
discharged from the system and may be used elsewhere or treated for recovery
of
surfactant therefrom.
The furnish may contain chemical additives to alter the physical properties
of the paper produced. These chemistries are well understood by the skilled
artisan and may be used in any known combination. Such additives may be
surface modifiers, softeners, debonders, strength aids, latexes, pacifiers,
optical
brighteners, dyes, pigments, sizing agents, barrier chemicals, retention aids,
insolubilizers, organic or inorganic crosslinkers, or combinations thereof;
said
chemicals optionally comprising polyols, starches, PPG esters, PEG esters,
phospholipids, surfactants, polyamines, HMCP or the like:
The pulp can be mixed with strength adjusting agents such as wet strength
agents, dry strength agents and debonders/softeners and so forth. Suitable wet
strength agents are known to the skilled artisan. A comprehensive but non-
I I
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exhaustive list of useful strength aids include urea-formaldehyde resins,
melamine
formaldehyde resins, glyoxylated polyacrylamide resins, polyamide-
epichlorohydrin resins and the like. Thermosetting polyacrylamides are
produced
by reacting acrylamide with diallyl dimethyl ammonium chloride (DADMAC) to
produce a cationic polyacrylamide copolymer which is ultimately reacted with
glyoxal to produce a cationic cross-linking wet strength resin, glyoxylated
polyacrylamide. These materials are generally described in United States
Patent
Nos. 3,556,932 to Coscia et al. and 3,556,933 to Williams et al.
Resins of this type are
commercially available under the trade name of PAREZ 631NC by Bayer
Corporation. Different mole ratios of acrylamide/-DADMAC/glyoxal can be used
to produce cross-linking resins, which are useful as wet strength agents.
Furthermore, other dialdehydes can be substituted for glyoxal to produce
thermosetting wet strength characteristics. Of particular utility are the
polyamide-
epichlorohydrin wet strength resins, an example of which is sold under the
trade
names Kymene 557LX and Kymene 557H by Hercules Incorporated of
Wilmington, Delaware and Amres from Georgia-Pacific Resins, Inc. These
resins and the process for making the resins are described in United States
Patent
No. 3,700,623 and United States Patent No. 3,772,076,
An extensive description of
polymeric-epihalohydrin resins is given in Chapter 2: Alkaline-Curing
Polymeric
Amine-Epichlorohydrin by Espy in Wet Strength Resins and Their Application (L.
Chan, Editor, 1994). A reasonably
comprehensive list of wet strength resins is described by Westfelt in
Cellulose
Chemist?), and Technology Volume 13, p. 813, 1979.
Suitable temporary wet strength agents may likewise be included. A
comprehensive but non-exhaustive list of useful temporary wet strength agents
includes aliphatic and aromatic aldehydes including glyoxal, malonic
dialdehyde,
succinic dialdehyde, glutaraldehyde and dialdehyde starches, as well as
CA 02559526 2012-02-09
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substituted or reacted starches, disaccharides, polysaccharides, chitosan, or
other
reacted polymeric reaction products of monomers or polymers having aldehyde
groups, and optionally, nitrogen groups. Representative nitrogen containing
polymers, which can suitably be reacted with the aldehyde containing monomers
or polymers, includes vinyl-amides, acrylamides and related nitrogen
containing
polymers. These polymers impart a positive charge to the aldehyde containing
reaction product. In addition, other commercially available temporary wet
strength agents, such as, PAREZ 745, manufactured by Bayer can be used, along
with those disclosed, for example in United States Patent No. 4,605,702.
The temporary wet gtrength resin may be any one of a variety of water-
soluble organic polymers comprising aldehydic units and cationic units used to
increase dry and wet tensile strength of a paper product. Such resins are
described
in United States Patent Nos. 4,675,394; 5,240,562; 5,138,002; 5,085,736;
4,981,557; 5,008,344; 4,603,176; 4,983,748; 4,866,151; 4,804,769 and
5,217,576.
Modified starches sold under the trademarks CO-BOND 1000 and CO-BOND
1000 Plus, by National Starch and Chemical Company of Bridgewater, N.J. may
be used. Prior to use, the cationic aldehydic water soluble polymer can be
prepared by preheating an aqueous shiny of approximately 5% solids maintained
at a temperature of approximately 240 degrees Fahrenheit and a pH of about 2.7
for approximately 3.5 minutes. Finally, the slimy can be quenched and diluted
by
adding water to produce a mixture of approximately 1.0% solids at less than
about
130 degrees Fahrenheit.
Other temporary wet strength agents, also available from National Starch
and Chemical Company are sold under the trademarks CO-BOND 1600 and
CO-BOND 2300. These starches are supplied as aqueous colloidal dispersions
and do not require preheating prior to use.
Temporary wet strength agents such as glyoxylated polyacrylamide can be
used. Temporary wet strength agents such glyoxylated polyacrylamide resins are
*Trade mark
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produced by reacting acrylamide with diallyl dimethyl ammonium chloride
(DADMAC) to produce a cationic polyacrylamide copolymer which is ultimately
reacted with glyoxal to produce a cationic cross-linking temporary or semi-
permanent wet strength resin, glyoxylated polyacrylamide. These materials are
generally described in United States Patent No. 3,556,932 to Coscia et al. and
United States Patent No. 3,556,933 to Williams et al., both of which are
incorporated herein by reference. Resins of this type are commercially
available
under the trade name of PAREZ 631NC, by Bayer Industries. Different mole
ratios of acrylamide/DADMAC/glyoxal can be used to produce cross-linking
resins, which are useful as wet strength agents. Furthermore, other
dialdehydes
can be substituted for glyoxal to produce wet strength characteristics.
Suitable dry strength agents include starch, guar gum, polyacrylamides,
carboxymethyl cellulose and the like. Of particular utility is carboxymethyl
cellulose, an example of which is sold under the trade name Hercules CMC, by
Hercules Incorporated of Wilmington, Delaware. According to one embodiment,
the pulp may contain from about 0 to about 15 lb/ton of dry strength agent.
According to another embodiment, the pulp may contain from about 1 to about 5
lbs/ton of dry strength agent.
Suitable debonders are likewise known to the skilled artisan. Debonders
or softeners may also be incorporated into the pulp or sprayed upon the web
after
its formation. The present invention may also be used with softener materials
including but not limited to the class of amido amine salts derived from
partially
acid neutralized amines. Such materials are disclosed in United States Patent
No.
4,720,383. Evans, Chemistry and Industry, 5 July 1969, pp. 893-903; Egan,
J.Am.
Oil Chemist's Soc., Vol. 55 (1978), pp. 118-121; and Trivedi et al., J.Am.Oil
Chemist's Soc., June 1981, pp. 754-756,
indicate that softeners are often available commercially only as complex
mixtures rather than as single compounds. While the following discussion will
CA 02559526 2012-02-09
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focus on the predominant species, it should be understood that commercially
available mixtures would generally be used in practice.
Quasoft 202-JR is a suitable softener material, which may be derived by
alkylating a condensation product of oleic acid and diethylenetriamine.
Synthesis
conditions using a deficiency of allcylation agent (e.g., diethyl sulfate) and
only
one alkylating step, followed by pH adjustment to protonate the non-ethylated
species, result in a mixture consisting of cationic ethylated and cationic non-
ethylated species. A minor proportion (e.g., about 10%) of the resulting amido
amine cyclize to imidazoline compounds. Since only the imidazoline portions of
these materials are quaternaiy ammonium compounds, the compositions as a
whole are pH-sensitive. Therefore, in the practice of the present invention
with
this class of chemicals, the pH in the head box should be approximately 6 to
8,
more preferably 6 to 7 and most preferably 6.5 to 7.
Quaternary ammonium compounds, such as dialkyl dimethyl quaternary
ammonium salts are also suitable particularly when the alkyl groups contain
from
about 10 to 24 carbon atoms. These compounds have the advantage of being
relatively insensitive to pH.
Biodegradable softeners can be utilized. Representative biodegradable
cationic softeners/debonders are disclosed in United States Patent Nos.
5,312,522;
5,415,737; 5,262,007; 5,264,082; and 5,223,096..
The compounds are biodegradable diesters of
quaternary ammonia compounds, quaternized amine-esters, and biodegradable
vegetable oil based esters functional with quaternary ammonium chloride and
diester dierucyldimethyl ammonium chloride and are representative
biodegradable
softeners.
In some embodiments, a particularly preferred debonder composition
includes a quaternary amine component as well as a nonionic surfactant.
*Trade mark
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The nascent web is typically dewatered on a papermaking felt. Any
suitable felt may be used. For example, felts can have double-layer base
weaves,
triple-layer base weaves, or laminated base weaves. Preferred felts are those
5 having the laminated base weave design. A wet-press-felt which may be
particularly useful with the present invention is Vector 3*made by Voith
Fabric.
Background art in the press felt area includes United States Patent Nos.
5,657,797;
5,368,696; 4,973,512; 5,023,132; 5,225,269; 5,182,164; 5,372,876; and
5,618,612.
A differential pressing felt as is disclosed in United States Patent No.
4,533,437 to
10 Curran et al. may likewise be utilized.
Any suitable creping belt or fabric may be used. Suitable creping fabrics
include single layer, multi-layer, or composite preferably open meshed
structures.
Fabrics may have at least one of the following characteristics: (1) on the
side of
15 the creping fabric that is in contact with the wet web (the "top" side),
the number
of machine direction (MD) strands per inch (mesh) is from 10 to 200 and the
number of cross-direction (CD) strands per inch (count) is also from 10 to
200;
(2) The strand diameter is typically smaller than 0.050 inch; (3) on the top
side,
the distance between the highest point of the MD knuckles and the highest
point
20 on the CD knuckles is from about 0.001 to about 0.02 or 0.03 inch; (4)
In
between these two levels there can be knuckles formed either by MD or CD
strands that give the topography a three dimensional hill/valley appearance
which
is imparted to the sheet during the wet molding step; (5) The fabric may be
oriented in any suitable way so as to achieve the desired effect on processing
and
on properties in the product; the long warp knuckles may be on the top side to
increase MD ridges in the product, or the long shute knuckles may be on the
top
side if more CD ridges are desired to influence creping characteristics as the
web
is transferred from the transfer cylinder to the creping fabric; and (6) the
fabric
may be made to show certain geometric patterns that are pleasing to the eye,
which is typically repeated between every two to 50 warp yarns. Suitable
*Trade mark
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commercially available coarse fabrics include a number of fabrics made by
Voith
Fabrics.
The creping fabric may thus be of the class described in United States
Patent No. 5,607,551 to Farrington et al, Cols. 7-8 thereof, as well as the
fabrics
described in United States Patent No. 4,239,065 to Trokhan and United States
Patent No. 3,974,025 to Ayers. Such fabrics may have about 20 to about 60
meshes per inch and are formed from monofilament polymeric fibers having
diameters typically ranging from about 0.008 to about 0.025 inches. Both warp
and weft monofilaments may, but need not necessarily be of the same diameter.
In some cases the filaments are so woven and complimentarily
serpentinely configured in at least the Z-direction (the thickness of the
fabric) to
provide a first grouping or array of coplanar top-surface-plane crossovers of
both
sets of filaments; and a predetermined second grouping or array of sub-top-
surface
crossovers. The arrays are interspersed so that portions of the top-surface-
plane
crossovers define an array of wicker-basket-like cavities in the top surface
of the
fabric which cavities are disposed in staggered relation in both the machine
direction (MD) and the cross-machine direction (CD), and so that each cavity
spans at least one sub-top-surface crossover. The cavities are discretely
perimetrically enclosed in the plan view by a picket-like-lineament comprising
portions of a plurality of the top-surface plane crossovers. The loop of
fabric may
comprise heat set monofilaments of thermoplastic material; the top surfaces of
the
coplanar top-surface-plane crossovers may be monoplanar flat surfaces.
Specific
embodiments of the invention include satin weaves as well as hybrid weaves of
three or greater sheds, and mesh counts of from about 10 X 10 to about 120 X
120
filaments per inch (4 X 4 to about 47 X 47 per centimeter). Although the
preferred
range of mesh counts is from about 18 by 16 to about 55 by 48 'filaments per
inch
(9 X 8 to about 22 X 19 per centimeter).
CA 02559526 2012-12-11
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Instead of an impression fabric, a dryer fabric may be used as the creping
fabric if so desired. Suitable fabrics are described in United States Patent
Nos.
5,449,026 (woven style) and 5,690,149 (stacked MD tape yarn style) to Lee as
well as United States Patent No. 4,490,925 to Smith (spiral style).
A creping adhesive used on the Yankee cylinder is preferably capable of
cooperating with the web at intermediate moisture to facilitate transfer from
the
creping fabric to the Yankee and to firmly secure the web to the Yankee
cylinder
as the web is dried to a consistency of 95% or more on the cylinder preferably
with a
high volume drying hood. The adhesive is critical to stable system operation
at
high production rates and is a hygroscopic, re-wettable, substantially non-
.
crosslinking adhesive. Examples of preferred adhesives are those that include
poly(vinyl alcohol) of the general class described in United States Patent No.
4,528,316 to Soerens et al.
Suitable adhesives are optionally provided with modifiers, and so forth. We
prefer
to use crosslinker sparingly, or not at all, in the adhesive in many cases,
such that
the resin is substantially non-crosslinkable in use.
The present invention is appreciated by reference to the Figures,
especially Figures 1 and 2. Figure 1 shows a cross-section (120X) along the MD
of a fabric-creped, sheet 10 illustrating a fiber-enriched, pileated region
12. It is
seen that the web has microfolds transverse to the machine direction, i.e.,
the
ridges or creases extend in the CD (into the photograph). It will be
appreciated
that fibers of the fiber-enriched region 12 have orientation biased in the CD,
especially at the right side of region 12, where the web contacts a knuckle of
the
creping fabric. The jet/forming wire velocity delta (jet velocity-wire
velocity) has
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23
an important influence on tensile ratio as is seen in Figure 2; an influence
which
is markedly different than that seen in conventional wet pressed products.
Figure 2 is a plot of MD/CD tensile ratio (strength at break) versus the
difference between headbox jet velocity and forming wire speed (fpm). The
upper
U-shaped curve is typical of conventional wet-press absorbent sheet. The
lower,
broader curve is typical of fabric-creped product of the invention. It is
readily
appreciated from Figure 2 that MD/CD tensiles of below 1.5 or so are achieved
in
accordance with the invention over a wide range of jet to wire velocity
deltas, a
range which is more than twice that of the CWP curve shown. Thus control of
the
headbox jet forming wire velocity may be used to achieve desired sheet
properties.
It is also seen from Figure 2 that MD/CD ratios below square (i.e. below
1) are difficult; if not impossible to obtain with conventional processing.
Furthermore, square or below sheets are formed by way of the invention without
a
lot of fiber aggregates or "flocs" which is not the case with the CWP products
with low MD/CD tensile ratios. This difference is due, in part, to the
relatively
low velocity deltas required to achieve low tensiles in CWP products and may
be
due in part to the fact that fiber is redistributed on the creping fabric when
the web
is creped from the transfer surface in accordance with the invention.
In many products, the cross machine properties are more important than
the MD properties, particularly in commercial toweling where CD wet strength
is
critical. A major source of product failure is "tabbing" or tearing off only a
piece
of towel rather than the intended sheet. In accordance with the invention, CD
relative tensiles may be selectively elevated by control of the headbox to
forming
wire velocity delta and fabric creping.
Figure 3 is a photomicrograph (10X) of the fabric side of a fabric-creped
web. It is again seen in Figure 2 that sheet 10 has a plurality of very
pronounced
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high basis weight, fiber-enriched regions 12 having fiber with orientation
biased
in the cross-machine direction (CD) linked by relatively low basis weight-
linking
regions 14, which have fiber orientation biased in a direction between
pileated or
fiber-enriched regions.
Orientation bias is also seen in Figure 1, especially where the CD-biased
fibers of the pileated, fiber-enriched regions 12 have been cut when making
the
specimens in the center of region 12. To the left of region 12, in the linking
region, it is seen that fiber is biased more along the machine direction
between
fiber-enriched regions. These features are also readily observed in Figure 3
at
lower magnification, where fiber bias in regions 14 extends between pileated
regions.
Figure 4 is a schematic diagram of a papermachine 15 having a
conventional twin wire forming section 17, a felt run 19, a shoe press section
16, a
creping fabric 18 and a Yankee dryer 20 suitable for practicing the present
invention. Forming section 12 includes a pair of forming fabrics 22, 24
supported
by a plurality of rolls 26, 28, 30, 32, 34, 36 and a forming roll 38. A
headbox 40
provides papermaking furnish in the form of a jet to a nip 42 between forming
roll
38 and roll 26 and the fabrics. Control of the jet velocity relative to the
forming
fabrics is an important aspect of controlling tensile ratio as will be
appreciated by
one of skill in the art. The furnish forms a nascent web 44 which is dewatered
on
the fabrics with the assistance of vacuum, for example, by 'way of vacuum box
46.
The nascent web is advanced to a papermaking felt 48 which is supported
by a plurality of rolls 50, 52, 54, 55 and the felt is in contact with a shoe
press roll
56. The web is of low consistency as it is transferred to the felt. Transfer
may be
assisted by vacuum; for example roll 50 may be a vacuum roll if so desired or
a
pickup or vacuum shoe as is known in the art. As the web reaches the shoe
press
roll it may have a consistency of 10-25 percent, preferably 20 to 25 percent
or so
as it enters nip 58 between shoe press roll 56 and transfer roll 60. Transfer
roll 60
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may be a heated roll if so desired. Instead of a shoe press roll, roll 56
could be a
conventional suction pressure roll. If a shoe press is employed it is
desirable and
preferred that roll 54 is a vacuum roll effective to remove water form the
felt prior
to the felt entering the shoe press nip since water from the furnish will be
pressed
5 into the felt in the shoe press nip. In any case, using a vacuum roll or
STR at 54 is
typically desirable to ensure the web remains in contact with the felt during
the
direction change as one of skill in the art will appreciate from the diagram.
Web 44 is wet-pressed on the felt in nip 58 with the assistance of pressure
10 shoe 62. The web is thus compactively dewatered at 58, typically by
increasing
the consistency by 15 or more points at this stage of the process. The
configuration shown at 58 is generally termed a shoe press; in connection with
the
present invention cylinder 60 is operative as a transfer cylinder which
operates to
convey web 44 at high speed, typically 1000 fpm-6000 fpm to the creping
fabric.
Cylinder 60 has a smooth surface 64 which may be provided with adhesive
and/or release agents if needed. Web 44 is adhered to transfer surface 64 of
cylinder 60 which is rotating at a high angular velocity as the web continues
to
advance in the machine-direction indicated by arrows 66. On the cylinder, web
44
has a generally random apparent distribution of fiber.
Direction 66 is referred to as the machine-direction (MD) of the web as
well as that of papermachine 10; whereas the cross-machine-direction (CD) is
the
direction in the plane of the web perpendicular to the MD.
Web 44 enters nip 58 typically at consistencies of 10-25 percent or so and
_
is dewatered and dried to consistencies of from about 25 to about 70 by the
time it
is transferred to creping fabric 18 as shown in the diagram.
,
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Fabric 18 is supported on a plurality of rolls 68, 70, 72 and a press nip roll
or solid pressure roll 74 such that there is formed a fabric crepe nip 76 with
transfer cylinder 60 as shown in the diagram.
The creping fabric defines a creping nip over the distance in which creping
fabric 18 is adapted to contact roll 60; that is, applies significant pressure
to the
web against the transfer cylinder. To this end, backing (or creping) roll 70
may be
provided with a soft deformable surface which will increase the length of the
creping nip and increase the fabric creping angle between the fabric and the
sheet
and the point of contact or a shoe press roll could be used as roll 70 to
increase
effective contact with the web in high impact fabric creping nip 76 where web
44
is transferred to fabric 18 and advanced in the machine-direction. By using
different equipment at the creping nip, it is possible to adjust the fabric
creping
angle or the takeaway angle from the creping nip. Thus, it is possible to
influence
the nature and amount of redistribution of fiber, delamination/debonding which
may occur at fabric creping nip 76 by adjusting these nip parameters. In some
embodiments it may by desirable to restructure the z-direction interfiber
characteristics while in other cases it may be desired to influence properties
only
in the plane of the web. The creping nip parameters can influence the
distribution
of fiber in the web in a variety of directions, including inducing changes in
the z-
direction as well as the MD and CD. In any case, the transfer from the
transfer
cylinder to the creping fabric is high impact in that the fabric is traveling
slower
than the web and a significant velocity change occurs. Typically, the web is
creped anywhere from 10-60 percent and even higher during transfer from the
transfer cylinder to the fabric.
Creping nip 76 generally extends over a fabric creping nip distance of
anywhere from about 1/8" to about 2", typically Y2" to 2". For a creping
fabric
with 32 CD strands per inch, web 44 thus will encounter anywhere from about 4
to 64 weft filaments in the nip.
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The nip pressure in nip 76, that is, the loading between backing roll 70 and
transfer roll 60 is suitably 20-100, preferably 40-70 pounds per linear inch
(PL).
After fabric creping, the web continues to advance along MD 66 where it
is wet-pressed onto Yankee cylinder 80 in transfer nip 82. Transfer at nip 82
occurs at a web consistency of generally from about 25 to about 70 percent. At
these consistencies, it is difficult to adhere the web to surface 84 of
cylinder 80
firmly enough to remove the web from the fabric thoroughly. Typically, a
poly(vinyl alcohol)/polyamide adhesive composition as noted above is applied
at
86 as needed.
If so desired, a vacuum box may be employed at 67 in order to increase
caliper. Typically, a vacuum of from about 5 to about 30 inches of Mercury is
employed.
The web is dried on Yankee cylinder 80 which is a heated cylinder and by
high jet velocity impingement air in Yankee hood 88. As the cylinder rotates,
web
44 is creped from the cylinder by creping doctor 89 and wound on a take-up
roll
90. Creping of the paper from a Yankee dryer may be carried out using an
undulatory creping blade, such as that disclosed in United States Patent No.
5,690,788, the disclosure of which is incorporated by reference. Use of the
undulatory crepe blade has been shown to impart several advantages when used
in
production of tissue products. In general, tissue products creped using an
undulatory blade have higher caliper (thickness), increased CD stretch, and a
higher void volume than do comparable tissue products produced using
conventional crepe blades. All of these changes effected by use of the
undulatory
blade tend to correlate with improved softness perception of the tissue
products.
There is optionally provided a calender station 85 with rolls 85(a), 85(b) to
calender the sheet if so desired.
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When a wet-crepe process is employed, an impingement air dryer, a
through-air dryer, or a plurality of can dryers can be used instead of a
Yankee.
Impingement air dryers are disclosed in the following patents and
applications:
United States Patent No. 5,865,955 of Ilvespaaet et al.
United States Patent No. 5,968,590 of Ahonen et al.
United States Patent No. 6,001,421 of Ahonen et al.
United States Patent No. 6,119,362 of Sundqvist et al.
United States Patent Application No. 09/733,172, entitled Wet
Crepe, Impingement-Air Dry Process for Making Absorbent Sheet,
now United States Patent No. 6,432,267.
A throughdrying unit as is well known in the art and described in United
States
Patent No. 3,432,936 to Cole et al. and
United States Patent No. 5,851,353 which discloses a can-
drying system.
Representative Examples
Using an apparatus of the general class of Figure 4, absorbent sheet was
prepared at various weights, crepe ratios and so forth. This material
exhibited
high CD stretch at low dry tensile ratios as is seen particularly in Figures 5
through 9. As will be appreciated from the foregoing discussion and the
following
examples, the relative basis weight of the fiber enriched regions and linking
regions, degree of pileation, fiber orientation and geometry of the reticulum
are
controlled by appropriate selection of materials and fabrics, as well as
controlling
the fabric crepe ratio, nip parameters and jet to wire velocity delta.
Data for representative products appears in Table 1 for basesheet and
Table 2 for converted sheet.
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In connection with the following Tables and Examples, the following
abbreviations sometimes appear:
BRT Bath tissue
CD, MD Without further specification, refers to
tensile strength
CD%, MD% - Stretch at break in the direction indicated
CMC Carboxy methyl cellulose
CWP Conventional Wet Press
FC Fabric crepe or fabric crepe ratio
GM, GMT - Geometric Mean, typically tensile
Mod Modulus
Ratio Dry Tensile Ratio, MD/ CD
SPR Solid pressure roll, roll 74 seen in Figure
4
STR Suction turning roll, roll 54 as seen in
Figure 4
Ton
TAD Through Air Dried
'819 Refers to emboss pattern of USP 6,827,819
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Table 1 - Representative Examples 1-194 - Basesheet Data
Basis Caliper Tensile
Weight 8 Sheet Tensile Stretch Tensile Stretch Tensile Dry
MD MD CD CD GM Ratio
lb/3000 mils/
Example ft^2 8 sht g/3 in % g/3 in % g/3 in.
%
1 24.8 77.1 1031 37.1 587 7.6 778 1.75
_
2 25.4 76.4 1107 37.2 621 7.0 829 1.78
3 24.6 77.9 948 37.3 539 7.4 715 1.76
4 25.6 75.9 1080 36.0 580 7.0 791 1.86
5 24.9 79.6 967 37.0 521 7.4 709 1.86
6 25.0 76.0 814 28.9 487 5.2 628 1.67
7 12.3 58.3 725 33.4 288 8.3 456 2.52
8 12.6 59.2 861 33.3 281 9.8 491 3.07
9 12.4 57.5 790 32.9 297 9.9 484 2.66
10 12.2 56.1 857 31.7 289 9.3 497 2.97
11 12.5 65.7 561 55.9 291 10.4 404 1.93
12 12.2 66.9 576 59.4 218 12.8 355 2.64
13 12.2 68.0 771 54.9 240 14.8 430 3.22
14 , 12.1 68.3 697 55.4 217 15.8 389
3.21
15 20.0 74.0 768 62.3 484 10.4 610 1.59
16 21.2 68.8 785 58.1 561 6.6 664 1.40
17 12.2 57.6 777 33.1 252 10.0 443 3.08
18 12.4 58.6 787 31.8 273 7.6 464 2.88
19 11.8 54.6 642 29.9 228 8.8 383 2.81
20 12.2 57.3 678 33.0 231 8.6 396 2.93
21 12.6 59.9 700 33.7 251 8.7 419 2.79
22 12.6 59.6 675 34.0 224 7.6 389 3.01
23 12.5 56.9 755 33.6 263 8.3 445 2.88
24 11.9 56.8 724 31.1 262 7.4 435 2.76
25 12.0 55.2 770 32.5 252 7.4 440 3.06
26 25.0 76.6 1245 46.6 769 7.0 979 1.62
27 24.4 67.7 1105 45.4 761 6.5 916 1.45
28 24.3 65.3 911 44.4 818 5.4 863 1.11
29 24.5 65.6 888 44.5 770 5.3 827 1.15
30 21.1 77.5 464 43.4 370 6.2 414 1.25
31 20.9 71.1 494 41.6 378 5.7 432 1.30
32 21.0 67.1 660 43.4 491 5.3 569 1.35
33 20.7 64.4 625 41.4 520 4.9 569 1.20
34 20.9 64.4 695 42.4 557 5.0 622 1.25
21.8 88.5 728 48.5 617 4.8 670 1.18
36 21.4 65.7 1012 48.8 806 6.5 903 1.26
37 20.8 77.6 673 47.9 605 6.0 638 1.11
38 20.6 75.7 682 46.7 701 5.5 691 0.97
= 39 20.6 64.2 722 44.2 699 5.5 710 1.03
20.8 64.8 726 44.0 684 5.1 705 1.06
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Table 1 - Representative Examples 1-194 - Basesheet Data (Cont'd)
Basis Caliper
Tensile
Weight 8 Sheet Tensile Stretch Tensile Stretch
Tensile Dry
MD MD CD CD GM Ratio
lb/3000 mils/
Example ft^2 8 sht g/3 in % g/3 in % g/3 in.
%
41 21.2 65.4 829 45.8 804 5.4 816
1.03
42 21.2 70.2 780 49.3 729 5.8 754
1.07
43 21.0 68.8 790 46.6 743 5.7 765
1.06
44 21.6 72.9 793 52.0 770 6.1 781
1.03
45 19.9 70.7 519 53.9 579 6.8 548
0.90
46 22.4 74.5 746 57.2 773 6.4 759
0.96
47 21.7 68.3 664 54.3 702 6.7 683
0.95
48 23.8 75.2 573 71.9 621 7.6 596
0.92
49 24.0 74.0 583 46.1 646 5.5 613
0.90
50 23.0 71.9 543 44.4 557 5.4 550
0.98
51 23.5 69.2 679 53.4 612 6.2 644
1.11
52 23.6 73.0 551 44.6 571 6.1 561
0.96
53 23.6 70.0 603 47.0 737 5.6 666
0.82
54 23.3 73.4 510 59.3 617 6.0 561
0.83
55 24.5 74.0 545 62.3 682 6.8 608
0.80
56 24.2 72.6 569 68.4 676 6.4 620
0.84
57 24.0 70.9 499 59.7 610 8.4 552
0.82
58 24.2 79.5 651 66.3 723 6.1 686
0.90
59 24.0 63.9 528 58.0 670 6.5 595
0.79
60 23.0 63.9 509 57.2 598 7.7 552
0.85
61 23.7 67.6 525 53.8 726 7.4 617
0.72
62 23.7 97.2 657 50.1 785 5.3 718
0.83
63 24.3 65.6 702 43.3 712 4.5 706
0.99
64 22.8 55.2 578 37.6 757 5.2 661
0.76
,
65 23.1 51.2 592 33.1 813 5.0 694
0.73
66 23.0 68.1 544 59.7 549 7.7 546
0.99
67 24.3 65.0 819 40.3 671 7.5 741
1.22
68 23.0 60.7 614 37.5 667 5.8 639
0.92
69 23.4 61.4 795 40.0 836 5.8 814
0.95
70 23.4 60.3 753 38.4 789 5.7 771
0.95
71 24.3 87.6 737 45.8 833 6.1 784
0.88
72 22.9 59.8 586 36.6 614 5.7 600
0.95
73 25.4 57.3 978 34.9 1043 5.4 1009
0.94
74 23.9 62.6 497 34.1 528 5.4 512
0.94
75 23.5 64.9 554 34.9 394 9.7 466
1.41
76 23.3 63.6 506 37.9 644 5.7 570
0.79
77 21.9 60.6 543 36.1 629 5.5 585
0.86
78 21.9 62.2 538 37.4 629 5.6 581
0.85
79 21.5 51.1 527 32.7 610 5.1 566
0.87
CA 02559526 2006-09-11
WO 2005/106117
PCT/US2005/012320
32
Table 1 - Representative Examples 1-194 - Basesheet Data (Cont'd)
Basis Caliper Tensile
Weight 8 Sheet Tensile Stretch Tensile Stretch Tensile Dry
MD MD CD CD GM Ratio
lb/3000 mils/ ,
Example ft^2 8 sht g/3 in % g/3 in % g/3 in. %
80 21.7 61.5 505 34.4 610 5.8 555 0.83
81 21.1 52.6 441 27.5 576 5.2 504 0.77
82 21.9 63.3 416 33.3 493 5.4 453 0.85
83 21.5 53.8 412 27.1 463 5.4 437 0.89
84 21.5 53.7 505 35.5 476 7.7 490 1.06
85 21.6 64.7 552 41.1 525 7.9 538 1.05
86 21.5 63.2 587 43.9 746 6.5 661 0.79
87 21.5 50.5 571 38.2 715 6.1 638 0.80
88 21.8 59.6 456 34.2 528 5.8 490 0.87
89 21.6 58.7 539 35.3 639 5.8 587 0.84
90 21.6 60.6 612 36.9 395 7.9 492 1.55
91 21.7 58.5 991 41.0 568 7.2 750 1.75
92 22.2 56.4 811 37.0 1051 5.0 923 0.77
93 22.9 84.6 1199 54.9 1318 5.6 1257
0.91
-
- - - - - - -
94 22.3 91.2 976 52.2 1205 5.8 1084
0.81
95 22.8 85.2 1236 53.7 1481 5.6 1353
0.83
96 22.9 84.7 1303 57.5 1553 5.9 1421
0.84
97 22.6 66.6 567 80.9 676 8.5 619 0.84
98 22.3 66.1 423 72.5 624 9.2 513 0.68
99 21.9 63.1 455 73.1 514 9.7 483 0.89
100 22.3 67.1 538 72.5 590 9.2 563 0.91
101 22.1 65.3 1141 48.0 769 7.6 937 1,48
102 22.1 66.3 851 47.2 638 7.9 735 1.34
103 22.1 64.5 780 _ 45.6 568 7.4 665 1.37
104 21.9 63.2 678 43.2 630 6.0 653 1.08
105 21.9 64.5 547 48.3 680 7.0 610 0.80 _
106 21.9 65.4 582 51.0 711 6.9 643 0.82
107 21.6 66.5 603 51.9 466 9.0 _ 530 1.29
108 21.9 64.6 457 48.3 591 6.7 520 0.77
109 16.7 48.0 2146 26.3 904 6.3 1393
2.37 _
110 17.1 52.1 2103 27.1 831 5.9 1322
2.53
111 21.1 65.0 692 46.6 596 6.6 642 1.16
112 22.0 57.1 2233 50.7 1658 6.9 _ 1924
1.35
113 21.0 62.7 1452 70.4 776 11.9 1061
1.87
114 21.6 63.5 1509 68.7 1066 10.7 1267
1.42
115 20.6 63.2 1369 69.2 948 10.8 1138
1.45
116 20.7 61.8 1434 70.4 943 10.1 1162
1.53
117 21.6 69.9 1322 70.5 964 10.6 1129
1.37
118 23.4 63.5 1673 50.2 1310 6.7 1480
1.28
CA 02559526 2006-09-11
WO 2005/106117
PCT/US2005/012320
33
Table 1 - Representative Examples 1-194 - Basesheet Data (Cont'cll
Basis Caliper Tensile
Weight 8 Sheet Tensile Stretch Tensile Stretch Tensile Dry
MD MD CD CD GM Ratio
Example lb/3000 mils/
ft^2 8 sht g/3 in % g/3 in % g/3 in. %
119 22.6 63.1 689 52.3 589 7.4 637 1.17
120 22.7 57.6 638 50.7 532 8.1 583 1.20
121 22.7 54.4 706 50.6 568 7.4 633 1.24
122 22.4 55.7 640 49.2 583 7.7 611 1.10 ,
123 23.1 57.7 559 46.4 513 7.1 535 1.09
124 23.0 57.6 617 49.0 488 7.0 548 1.27
125 22.9 57.6 597 49.2 478 7.4 534 1.25
126 22.7 56.5 641 49.2 599 6.8 620 1.07
127 22.7 59.6 583 49.4 519 7.4 549 1.13
128 23.0 58.2 702 52.7 586 7.6 641 1.20
129 23.5 59.1 713 52.3 579 7.1 642 1.23
130 23.3 58.9 626 49.3 560 7.6 592 1.12
131 22.7 58.8 624 75.1 587 10.9 605 1.06
132 23.0 59.8 683 78.7 572 11.5 625 1.19
133 22.8 56.9 852 51.7 695 6.8 769 1.23 _
134 22.9 55.8 896 50.9 709 6.9 796 1.27
135 22.9 56.7 849 50.5 607 6.8 716 1.42
136 23.5 57.6 843 49.4 702 6.5 769 1.20
137 23.2 55.0 615 50.5 684 5.3 648 0.90
138 22.9 58.9 702 76.5 533 10.8 612 1.32
139 21.2 50.8 1068 53.8 996 7.8 1031 1.07
140 20.9 52.0 993 39.2 829 7.6 906 1.20
141 20.9 51.4 1062 53.1 846 7.8 948 1.26
142 20.6 51.7 712 49.2 601 9.1 651 1.19
143 20.7 60.2 877 59.2 594 9.8 722 1.48
144 20.8 60.0 801 63.3 474 10.5 616 1.69
145 18.9 56.0 669 61.6 459 10.9 554 1.46
146 17.0 51.2 555 50.9 580 7.8 567 0.96
147 23.0 53.7 649 29.5 585 4.6 615 1.11
148 20.1 52.2 1098 52.0 1048 5.7 1072 1.05
149 20.1 53.6 517 45.4 472 6.1 494 1.10
150 20.4 55.4 601 43.2 500 5.4 548 1.20
151 20.4 52.8 864 33.6 600 5.0 720 1.44
152 20.5 55.0 798 32.5 745 4.6 771 1.07
153 20.6 58.5 712 38.1 636 5.4 -) 673 1.12 _
154 20.6 60.5 725 39.3 635 5.3 678 1.14
155 20.6 61.2 680 40.1 592 5.4 634 1.15
156 20.5 60.5 725 36.4 648 5.2 685 1.12
157 20.3 60.0 635 35.9 610 5.3 620 1.05
158 20.4 58.7 713 37.5 604 5.7 655 1.18
159 20.5 61.1 743 36.7 651 5.6 695 1.14 _
CA 02559526 2006-09-11
WO 2005/106117
PCT/US2005/012320
,
34
Table 1 - Representative Examples 1-194 - Basesheet Data (Cont'd)
Basis Caliper Tensile
Weight 8 Sheet Tensile Stretch Tensile Stretch Tensile Dry
MD MD CD CD GM Ratio
lb/3000 mils/
Example ft^2 8 sht g/3 in % g/3 in % g/3 in. %
160 19.8 60.0 691 40.7 611 4.9 650 1.13
161 19.7 59.0 761 40.9 682 4.9 720 1.12
162 20.2 60.4 729 39.2 678 5.0 702 1.08
163 20.0 60.3 781 40.6 665 5.1 720 1.17
164 20.1 58.1 708 36.3 645 5.3 676 1.10
165 20.0 56.8 760 36.7 663 4.9 709 1.15
166 19.9 57.2 684 39.3 610 5.8 645 1.12
167 21.0 63.8 810 48.0 885 6.2 846 0.91
168 20.8 66.5 758 54.1 656 7.3 705 1.15
169 21.0 66.1 696 53.0 619 7.5 656 1.12
170 20.9 66.2 637 52.6 540 7,6 586 1.18
171 21.3 63.6 641 30.1 531 4.4 583 1.21
172 21.4 78.7 580 30.8 486 4.3 530 1.20
173 21.0 65.8 570 21.4 479 4.1 521 1.20
174 20.8 71.5 978 52.5 859 6.5 916 1.14
175 20.0 57.0 714 41.5 644 5.2 678 1.11
176 20.4 65.6 560 41.2 746 4.7 647 0.75
177 20.2 67.7 489 41.6 648 4.7 563 0.76
178 20.4 67.1 543 39.6 662 4.6 599 0.82
179 20.2 67.9 500 39.7 646 4.6 568 0.77
180 20.4 69.5 497 39.5 650 4.8 568 0.76
181 19.8 66.2 476 38.5 602 4.4 535 0.79
182 20.5 68.8 682 42.3 665 5.4 673 1.03
183 20.3 71.0 672 41.1 668 5.7 670 1.01
184 20.2 69.8 672 42.1 613 5.3 641 1.10
185 21.0 72.4 693 42.1 670 5.9 681 1.03
186 21.0 73.2 801 43.2 752 5.6 776 1.07
187 20.6 70.0 774 43.3 746 5.9 759 1.04
188 20.5 76.6 670 60.7 644 6.9 657 1.04
189 20.3 74.2 649 57.1 671 7.0 660 0.97
190 20.3 77.6 765 58.6 719 7.5 740 1.07
191 20.3 78.9 764 62.5 710 7.5 736 1.08
192 20.5 78.8 776 62.7 696 7.5 735 1.12
193 20.6 78.9 889 64.5 776 7.8 830 1.15
194 20.7 67.4 1368 43.5 1305 5.2 1335
1.05
CA 02559526 2006-09-11
WO 2005/106117 PCT/US2005/012320
Table 2 - Representative Examples 195-272 - Finished Product Data
Sensory Softness at
MDBr CDBr GMBr MD/
Example Emboss Softness 450 GMT BW Caliper MD CD GMT MD% CD% Mod Mod Mod CD
195 none 15.6 15.9
20.3 58.8 578 478 526 32.9 4.3 17.6 112.1 44.4 1.21
196 '819 16.3 16.2
18.7 70.9 509 346 420 25.4 6.1 20.0 57.1 33.8 1.47
197 none 15.3 15.6
22.3 68.2 561 556 559 53.9 6.9 10.4 81.5 29.1 1.01
198 '819 15.9 16.0
21.2 75.1 504 495 499 46.0 7.7 10.9 64.6 26.6 1.02
199 none 15.6 16.2
23.6 65.8 613 596 604 34.6 4.9 17.7 123.9 46.8 1.03
200 '819 16.3 16.1
20.9 72.6 450 354 399 23.0 5.4 19.6 65.1 35.7 1.27
201 none 15.4 16.0
22.2 62.9 614 618 616 36.0 4.9 17.1 125.7 46.3 0.99
202 '819 15.8 16.1
21.6 74.6 579 493 534 28.7 6.1 20.2 81.1 40.4 1.17
203 none 15.9 16.1
22.9 65.7 505 503 504 30.3 5.3 16.6 96.0 39.9 1.00
204 '819 16.3 16.2
21.8 78.7 468 400 432 24.6 6.4 19.0 62.8 34.5 1.17
205 none 15.5 16.2
23.0 64.8 605 677 640 37.2 4.6 16.3 145.6 48.7 0.89
206 '819 15.9 16.2
21.6 76.7 510 520 515 28.1 6.2 18.2 83.9 39.1 0.98
207 none 15.8 16.1
22.6 68.7 493 559 525 46.6 5.5 10.6 101.7 32.8 0.88
208 '819 16.1 16.1
20.7 73.7 457 446 451 37.7 6.7 12.1 67.1 28.5 1.03
209 none 15.2 15.6
23.4 67.3 496 628 558 45.4 6.0 10.9 104.9 33.8 0.79
210 '819 15.9 16.1
22.1 76.4 498 514 506 40.0 6.7 12.5 76.5 30.9 0.97
211 none 15.4 15.8
22.6 70.1 567 561 564 50.8 5.0 11.1 111.9 35.3 1.01
212 '819 16.2 16.3
20.7 75.8 505 447 475 36.8 6.8 13.7 66.1 30.1 1.13
213 none 15.7 16.1
24.2 67.0 536 583 559 47.5 6.9 11.3 84.4 30.9 0.92
214 '819 16.2 16.2
21.7 72.9 444 427 435 38.6 7.8 11.5 54.9 25.1 1.04
215 none 16.3 16.6
22.2 62.0 495 567 529 46.7 6.0 10.6 94.3 31.6 0.87
CA 0255 952 6 200 6-0 9-11
WO 2005/106117 PCT/US2005/012320
=
36
Table 2 - Representative Examples 195-272 - Finished Product Data (cont'd)
Softness
Sensory at 450
MDBr CDBr GMBr MD/
Example Emboss Softness GMT BW Caliper MD _ CD GMT MD% CD% _ Mod Mod Mod CD
216 '819 16.3 16.2 20.8 68.2 414 427 - 420
37.7 7.0 11.0 60.9 25.9 0.97
217 none 16.3 16.6 22.7 60.7 519 540 530
50.8 6.3 10.2 - 8= 6.1 29.7 0.96
218 '819 16.6 16.6 21.3 68.0 483 438 460
42.4 7.6 11.4 - 5= 8.0 25.7 1.10
219 none 16.0 16.7 24.1
64.6 593 711 649 51.0 6.8 11.6 104.5 34.9 0.83
220 '819 16.3 16.7 22.3 71.9 547 561
554 42.8 7.9 12.8 72.0 30.3 0.97
221 none 16.3 16.6 23.3 66.0 537 532
534 50.9 7.1 10.5 74.9 28.1 1.01
222 '819 16.3 16.1 20.6 70.2 426 379 402
37.4 8.5 11.4 - 4= 4.7 22.5 1.12
223 none 15.9 16.4 - 2= 2.8 56.4 565 610 587
30.5 5.0 18.5 123.1 47.7 0.93
224 '819 16.6 16.4 20.9 68.2 440 362
399 25.3 5.7 17.4 63.4 33.2 1.22
225 '819 16.9 16.5 - 2= 2.5 68.2 347 330 338
23.3 6.2 14.9 53.3 28.2 1.05
226 '819 16.8 16.6 21.9 67.5 524 299
396 29.9 9.8 17.5 30.5 23.1 1.75
227 '819 16.6 16.6 21.0 68.6 443 -435 439 26.6
6.0 16.7 73.2 35.0 1.02
228 '819 16.8 16.7 20.8 60.6 429 -432 430 23.3
5.5 18.5 76.4 37.6 0.99
229 '819 16.6 16.4 20.7 68.9 373 -392 382 19.3
5.6 19.5 70.3 37.0 0.95
230 '819 16.9 16.6 20.4 61.5 364 360
362 17.7 5.1 20.9 70.7 38.4 1.01
231 '819 17.3 16.7 20.4 70.6 314 286
300 17.4 5.8 17.9 49.4 29.7 1.10
232 '819 17.4 16.9 20.3 65.1 306 284
295 15.7 5.9 19.3 48.5 30.6 1.08
233 '819 16.7 16.5 20.4 64.4 452 355
401 25.5 8.1 18.2 44.1 28.3 1.27
234 '819 16.5 16.4 20.3 69.9 484 385
432 27.5 7.9 17.5 48.3 29.1 1.26
,
235 '819 16.1 16.2 20.4 69.1 488 497
492 27.7 6.8 17.6 72.2 35.7 0.98
236 '819 16.3 16.5 20.7 65.3 482 -549 514
27.3 6.3 17.9 86.6 ' 39.4 0.88
237 '819 18.3 18.0 20.3 64.7 403 _325 362 22.9
5.7 17.6 56.8 31.6 1.24
238 '819 17.7 17.6 _ 20.2 65.9 463 393
427 24.4 5.9 19.0 67.0 35.7 1.18
,
239 '819 18.2 17.9 20.3 63.3 494 278
371 25.0 7.8 19.8 35.9 26.6 1.78
240 '819 17.9 18.1 20.4 68.2 494 515
504 55.8 8.4 8.9 61.7 23.4 0.96
241 '819 17.8 17.8 20.3 65.4 467 424
445 50.6 8.7 9.2 48.8 21.2 1.10
242 '819 15.7 16.7 20.9 68.0 938 _579 737
35.0 7.4 26.8 78.7 45.9 1.62
243 '819 16.1 16.5 20.6 68.9 709 456
569 32.9 7.6 21.6 60.0 35.9 1.55
244 '819 16.8 16.9 20.1 67.1 556 434
491 30.6 6.7 18.2 65.1 34.4 1.28
245 '819 16.3 16.2 20.3 67.0 471 345 403
37.6 _ 8.7 12.6 39.8 22.4 1.37
246 '819 16.4 16.2 20.4 67.8 397 438 417
34.1 7.1 11.7 61.1 26.7 _ 0.91
247 '819 16.7 16.7 21.2 60.9 _ 525 422 471
34.6 _ 7.5 15.2 56.3 29.2 1.24
248 '819 15.8 16.2 22.0 60.5 _ 628 520 571
66.4 11.2 _ 9.4 47.5 21.1 1.21
249 '819 16.1 16.4 22.1 59.4 _ 636 458 540
62.9 10.8 _ 10.1 42.0 20.6 , 1.39
250 B&S,M 17.3 17.0 19.2 64.3 _ 479
295 376 33.8 6.1 14.3 49.6 26.6 1.62
251 Mos.Iris 17.5
17.5 20.0 59.7 517 372 439 36.7 6.2 14.1 59.7 29.0 1.39
252 B&S,M 16.6 16.5 19.8 67.0 487
359 418 _ 27.0 5.5 17.7 65.0 34.3 1.36
253 B&S,M 16.9
16.6 19.1 65.0 453 303 370 26.0 5.2 17.4 58.0 31.6 1.50
254 B&S,M 17.0
17.0 19.4 69.1 537 379 451 25.6 5.3 20.8 73.8 39.2 1.42
CA 02559526 2006-09-11
WO 2005/106117 PCT/US2005/012320
37
Table 2 - Representative Examples 195-272 - Finished Product Data (cont'd)
Softness
Sensory at 450 MDBr CDBr GMBr MD/
Example Emboss Softness GMT BW Caliper MD CD GMT MD% CD% Mod Mod Mod CD
255 Mos.Iris 17.6 17.7 19.9 65.1 571 398 477 28.4 5.4
20.1 73.8 38.5 1.43
256 B&S,M 17.0 16.9 19.3 65.8 507 347 419 25.2 5.4
20.0 64.3 35.8 1.46
257 Mos.Iris 18.1 18.3 19.5 65.4 603 427 507 31.9 5.1
18.9 83.8 39.8 1.41
258 B&S,M 18.0 18.0 18.7 67.3 553 373 454 28.9 4.9
19.1 76.2 38.1 1.48
259 B&S,M 17.9 18.0 19.0 69.0 594 385 478 30.0 5.3
20.8 74.3 39.0 1.54
260 B&S 17.1 17.0 19.6 68.1 521 334 417 30.2 6.5
17.5 51.9 30.1 1.56
261 B&S 16.3 16.3 20.5 76.4 _513 401 454
39.0 8.1 13.1 49.3 25.4 1.28
262 DH 16.9 17.0 21.9 70.0 _672 353 487
19.0 5.0 35.0 71.0 50.0 1.90
263 B&S 16.8 17.1 22.1 64.0 700 406 533 21.0 4.0
34.0 94.0 57.0 1.72
264 none 16.6 17.3 22.5 63.0 814 518 649 23.0 4.0
35.0 137.0 69.0 1.57
265 DH 16.6 17.4 21.8 68.0 1166 407 688 23.9 6.2
49.0 66.0 57.0 2.86
266 DH 17.6 17.7 17.0 65.0 583 413 491 31.0 6.0
19.0 69.0 36.0 1.41
267 DH 17.8 17.7 22.8 77.0 485 385 432 32.0 6.0
15.0 68.0 32.0 1.26
268 DH 16.4 16.6 23.0 85.0 658 370 493 29.0 6.0
23.0 58.0 36.0 1.78
269 DH 17.9 18.0 21.1 _78.0 565 393 471 30.0 5.0
19.0 77.0 38.0 1.44
270 DH 17.8 18.3 21.4 84.0 792 431 584 31.0 6.0
25.0 76.0 44.0 1.84
271 M3 18.6 18.5 20.8 104.0 629 291 428
25.0 7.0 25.0 41.0 32.0 2.16
272 DH 17.4 18.0 21.5 86.0 844 468 628 32.0 6.0
26.0 84.0 47.0 1.80 _
273 B&S 16.4 16.2 21.0 72.8 482 367 421 21.8 4.7
22.2 78.4 41.7 1.32
274 B&S 16.2 16.1 20.4 77.9 498 332 407 22.1
4.9 22.5 67.5 39.0 1.50
275 B&S 16.5 16.3 20.5 71.3 459 309 377 16.5 4.6
27.9 67.9 43.5 1.49
255 Mos.Iris 17.6 17.7 19.9 65.1 571 398 477 28.4 5.4
20.1 73.8 38.5 1.43
256 B&S,M 17.0 16.9 19.3 65.8 507 347 419 25.2 5.4
20.0 64.3 35.8 1.46
257 Mos.Iris 18.1 18.3 19.5 65.4 603 427 507 31.9 5.1
18.9 83.8 39.8 1.41
258 B&S,M 18.0 18.0 18.7 67.3 553 373 454 28.9 4.9
19.1 76.2 38.1 1.48
259 B&S,M 17.9 18.0 19.0 69.0 594 385 478 30.0 5.3
20.8 74.3 39.0 1.54
260 B&S 17.1 17.0 19.6 68.1 521 334 417 30.2 6.5
17.5 51.9 30.1 1.56
261 B&S 16.3 16.3 20.5 76.4 513 401 454 39.0 8.1
13.1 49.3 25.4 1.28 _
262 DH 16.9 17.0 21.9 70.0 672 353 487 19.0 5.0
35.0 71.0 50.0 1.90
263 B&S 16.8 17.1 22.1 64.0 700 406 533 21.0 4.0
34.0 94.0 57.0 1.72
264 none 16.6 17.3 22.5 63.0 814 518 649 23.0 4.0
35.0 137.0 69.0 1.57
265 DH 16.6 17.4 21.8 68.0 1166 407 688 23.9 6.2
49.0 66.0 57.0 2.86
266 DH 17.6 17.7 17.0 65.0 583 413 491 31.0 6.0
19.0 69.0 36.0 1.41
267 DH 17.8 17.7 22.8 77.0 485 385 432 32.0
6.0 15.0 68.0 32.0 1.26
268 DH 16.4 16.6 23.0 85.0 658 370 493 29.0 6.0
23.0 58.0 36.0 1.78
269 DH 17.9 18.0 21.1 78.0 565 393 471 30.0 5.0
19.0 77.0 38.0 1.44
270 DH 17.8 18.3 21.4 84.0 792 431 584 31.0 6.0
25.0 76.0 44.0 1.84
271 M3 18.6 18.5 20.8 104.0 _629 291 428
25.0 7.0 25.0 41.0 32.0 2.16
272 DH 17.4 18.0 21.5 86.0 844 468 628 32.0 6.0
26.0 84.0 47.0 1.80
CA 02559526 2006-09-11
WO 2005/106117
PCT/US2005/012320
38
Tissue Products
Tissue Products (non-permanent wet strength grades where softness is a
key parameter) made with a high solids fabric crepe process as described
herein
can use many of the same process parameters as would be used to make towel
products (permanent wet strength grades where absorbency is important,
strength
in use is critical, and softness is less important than in tissue grades.) In
either
category, 1-ply and 2-ply products can be made.
Fibers: Soft tissue products are optimally produced using high amounts of
hardwood fibers. These fibers are not as coarse as the longer, stronger,
softwood
fibers. Further, these finer, shorter, fibers exhibit much higher counts per
gram of
fiber. On the negative side, these hardwood pulps generally contain more fines
that are a result of the wood structures from which the pulp was made.
Removing
these fines can increase the numbers of actual fibers present in the final
paper
sheets. Also, removing these fines reduces the bonding potential during the
drying process, making it easier to debond the sheet either with chemicals or
with
blade creping at the dry end of the paper machine. The key benefit derived
from
high fiber counts per gram of pulp is sheet opacity or lack of transparency.
Since
a large part of a tissue sheet's performance is judged visually even before
the
sheet is touched, this optical property is an important contributor to the
perception
of quality. Softwood fibers are usually needed to provide a mesh-like
structure
on which the hardwood fibers can be arranged to optimize softness and optical
properties. But even in the case of softwoods, fiber coarseness and fibers per
gram are important properties. Long, thin, flexible, softwood fibers like
northern
softwoods present many more fibers per gram than do the long, coarse, thick,
stiff
southern softwoods. The net result of fiber selection is that with this
technology,
like all others, northern softwoods and low fines, low coarseness hardwoods
like
eucalyptus make softer sheets at a given tensile than do northern hardwoods
and
more so southern hardwoods.
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Chemicals: Tissue sheets generally employ a variety of chemicals to help
meet consumer demands for performance and softness. Generally, it is much
preferred to apply a dry strength chemical to the long fiber portion of the
pulp
blend than to use a refiner to develop tensile. Refining generates fines and
tends
to make more bonds of higher bonding strength because refining makes the
fibers
more flexible, which increases the potential for fiber-fiber contacts during
drying.
On the other hand, dry strength additives increase the strengths of the
available
bonds without increasing the number of bonds. Such a sheet then ends up being
inherently more flexible even before the fabric creping step of the fabric
crepe
process. Applying a debonding chemical to the hardwood portion is desirable so
that these hardwood fibers have a lower propensity of bonding to each other,
but
retain the capability of being bonded to the network of softwood fibers that
is
primarily responsible for the working tensile strengths of the paper. In some
cases, a temporary wet strength agent can also be added along with the
softwood
and hardwood fibers to improve the perception of wet strength performance
without sacrificing flush ability or septic tank safeness.
Fabric Creping: This process step is primarily responsible for the unique
and desirable properties of a tissue sheet. Increased fabric creping increases
caliper and decreases tensiles. Further, fabric creping changes the tensile
ratios
measured in the base sheets allowing sheets with equal MD/CD tensiles or
sheets
with lower MD than CD tensiles. However, it is desirable for tissue sheets to
exhibit equal tensiles in the two directions as most products are used in a
manner
independent of sheet direction. For example, "poke through" in a toilet paper
is
influenced by this tensile ratio along with the fact that fabric creping
develops
higher CD stretch, especially at lower MD/CD ratios than conventional
technology. With other technologies, equal tensile material is difficult to
run
through high speed processing equipment due to the propensity of tears
initiated at
an edge tend to propagate across the sheet causing a break. In contrast to
conentional producs, fabric creped sheets of equal tensile ratio made by way
of the
inventive process retain the tendency to tear along the MD direction, thereby
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exhibiting a tendency to self-healing should an edge tear occur and begin to
propagate into the sheet. This unexpected and unique property along with the
resistance of the stretch put into the sheet at this step to being pulled out
allows
efficient, high speed, operations at tensile ratios of one or less. Further,
these
5 same properties result in clean tears at perforations in the final
products. Levels
of fabric crepe for tissue products ranges from about 30 percent up to about
60
percent. While more is possible, this range allows for a wide variety of
quality
levels with no changes in the productivity at the paper machine.
10 Fabrics: The design of the fabrics is a salient aspect of the process.
But
the parameters of the fabric go beyond the size and depth of the depressions
woven into it. Their shape and placement is also very important. Diameters of
the strands making up the woven fabric are also important. For example, the
size
of the knuckle that stands at the leading edge of the depression into which
the
15 sheet will be creped determines the parameters of fabric crepe ratio and
basis
weight at which holes will appear in the sheet. The challenge, especially for
tissue
grades, is to make these depressions as deep as possible with finest possible
strand
diameters, thereby allowing greater fabric crepe ratios resulting in higher
sheet
calipers at a given ratio. Clearly, fabric designs need to change based upon
the
20 weight of the sheet being produced. For example, a very high quality,
premium,
2-ply bathroom tissue exhibiting high strength, caliper, and softness can be
made
on a 44M-design fabric. The 44G can also be used to make a heavier (up to 2x)
weight single ply sheet with very good results. Another property of the fabric
design is to impart a pattern into the sheet. Some fabric designs can impart a
very
25 noticeable pattern while others produce a pattern that seems to
disappear into the
background. Often times, consumers want to see the embossing pattern put into
the sheet at converting and in these instances a lesser sheet pattern might be
more
desirable. Some grades may be made without embossing and so a more distinct
pattern imparted by the fabric creping step would help impart a "premium" look
to
30 the sheet. Consumers tend to view plain sheets as lower quality, lower
priced
products.
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Creping: Since in a typical fabric crepe process of the invention the sheet
is transferred to a Yankee dryer for final drying, the sheet can be (and
usually is)
creped off this dryer to further enhance the softness. Tissue products benefit
greatly from this creping step that adds caliper and softness to the sheet. It
especially makes for a smooth surface on the Yankee side of the sheet.
Further,
since the ratio of reel crepe and fabric crepe can be varied independent of
production rate (reel speed) there is considerable latitude in changing the
properties of the final sheet. Increasing the reel crepe/fabric crepe ratio
decreases
the two sidedness of the paper since less fabric crepe will be put in for a
level of
MD stretch. There less prominent "eyebrow" structures in the paper that can
affect two-sidedness. Further, increasing that ratio also increases the
opacity and
the perception of thickness at the same measured caliper. Often it is
desirable to
maintain a reasonable ratio (say 25 to 50 percent reel crepe/fabric crepe) to
enhance consumer perceptions of these "intangible" properties associated with
the
visual appearance of the sheet.
Calendering: By all accounts, more calendering is better insofar as a
reasonable level of caliper is maintained in the sheet for subsequent
converting.
Too little caliper requires too much embossing which then degrades the overall
quality. Therefore, one strategy for producing for quality toilet paper is use
the
coarsest fabric without putting holes in the sheet, reducing the fabric
creping level
so that more of the MD stretch will come from the reel crepe portion and still
get
sufficient caliper prior to calendering so that at least about 20-40% of this
caliper
may be removed during the calendering step. These calendering levels tend to
reduce the sidedness of sheets. Alternatively, a quality sheet can be made
with a
finer fabric but with a lower reel crepe/fabric crepe ratio. Since the finer
fabric
produces more, smaller, domes, more fabric creping can be used to obtain the
desired caliper without unduly increasing sidedness. In most cases, reduced
sidedness is obtained. In this scenario the reel crepe/fabric crepe ratio can
be as
low as about 5-10%. Calendering can then be maximized to achieve the desired
softness. This method is desirable when relatively strong fibers are used as
the
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fabric creping dramatically reduces tensile strengths and when the design of
the
fabric produces less than average two-sidedness in the sheet.
Towel Products
Towel Products behave in a fashion similar to the tissue sheets to various
process parameters. However, in many cases towel products utilize the same
parameters but in an opposite direction with some in the same direction. For
example, both product forms desire caliper as caliper relates directly to
softness in
tissue products and absorbency in towel products. In the following parameters,
only the differences from tissue situations will be discussed.
Fibers: Towels require functional strength in use, which usually means
when wetted. To reach these needed tensiles, long softwood fibers are used in
ratios about opposite that of tissue products. Ratios of 70 to 90 percent
softwood
fibers are common. Refining can be used but tends to close up the sheet so
much
so that the subsequent fabric creping cannot "open" the structure. This
results in
slower absorbency rates and lower capacities. Unlike tissue products, fines
can be
utilized in towel sheets providing that not too much hardwood is used as this
again
would tend to close the sheet and also to reduce its tensile capability.
Chemicals: Surprisingly, debonders can also be used in towels! But their
use must be done judiciously. Likewise, refining of the fibers needs to be
regulated to lower levels to keep the sheet open and a quick absorber.
Therefore
chemical strength agents are routinely added. Of course wet strength chemicals
must be added to prevent shredding in use. But to get to high wet tensile
levels
the ratio of wet to dry tensiles must be maximized. If dry tensile levels get
too
high the towel sheet becomes too "papery" and is judged as low quality by
consumers. Therefore, wet strength agents and CMC are added to increase the
CD wet/dry ratio from the typical 25% up to the desired 30-35% range. Then to
produce a softer¨and thus a sheet perceived by consumers as more premium¨
sheet debonder can be added which preferentially reduces the CD dry tensile
over
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the wet value. Debonders and softeners can also be sprayed onto the sheet
after it
has dried to further improve the tactile properties.
Fabric Creping: Increasing the fabric creping increases the absorbency
directly. Therefore it is desirable to maximize fabric creping. However, FC
also
reduces tensiles so there is the balance that must be maintained. Towel sheets
sometimes cannot exhibit high levels of MD stretch because of the type of
dispensers that are used. In these cases FC must also be limited. Therefore,
towels require a coarser fabric design on average than do tissue sheets.
Further,
since these wet sheets will typically exhibit considerable wet strength, they
may
be more difficult to mold at the same consistency as a tissue sheet.
Fabrics: Coarse fabrics are desirable for towels in general. Two-ply towel
sheets are typically made on a 44G or 36G fabric or coarser with good results,
although good results can be obtained with finer fabrics, particularly if the
fabric
crepe ratio is increased. One-ply sheets often require an even coarser fabric
along
with other technology to make and acceptable sheet. The longer fibers in the
sheets and the higher strengths permit the use of these fabrics and higher FC
ratios
before holes appear in the sheets.
Creping: Very little creping is done on towel sheets. Creping does
increase caliper but does so in a manner similar to CWP sheets. This caliper
disappears when wetted and the sheet expands. Caliper from fabric creping acts
like a dry sponge when wetted. The sheet expands in the Z-direction and can
shrink in the MD & CD directions. This behavior adds greatly to the perceived
absorbency of the towels and makes them look similar to TAD towels. In many
cases, using the serrated blades of Taurus technology in conjunction with
fabric
crepe process improves the absorbency, caliper, and softness of the towel
sheet.
The CD stiffness is reduced while the CD stretch is increased. The higher
caliper
produced at the blade allows more calendering and hence more sheet smoothness.
In some cases it is desirable to pull the sheet off the Yankee dryer surface
without
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creping. This might be the case for washroom hand towels where softness is
less
important than getting more sheets on a roll. See United States Patent No.
6,187,137 to Druecke et al. as well as copending United States Patent
Application
No. 11/108,375 (now U.S. Patent No. 7,789,995) and No. 11/108,458 (now U.S.
Patent no.
7,442,278).
Calendering: Towel sheets benefit from calendering for two key reasons.
First, calendering smoothes the sheets and improves the tactile feel. Second,
it
"crushes" the domes produced by the fabrics imparting more Z-direction depth
to
the feel of the sheet and often improve the absorbent properties at a given
caliper.
Data Summary for Tissue
Several paper machine process tools and emboss patterns were used to
produce 1-ply retail and commercial bathroom tissue. Process variables
included:
fabric crepe percent, reel crepe percent, softener addition level, softener
type,
softener location, fiber type, HW/SW ratio, calendering load, rubber and steel
calendering, creping fabric style, MD/CD ratio and Yankee coating chemistry.
The emboss patterns included: '819, M3, Double Hearts, Butterflies and Swirls,
Butterflies and Swirls with Micro and Mosaic Iris. The best commercial 1-ply
bathroom tissue (BRT) prototype containing 40% Northern HW and 60% recycled
fiber, at 20 lb basis weight and 450 GMT, achieved a 17.5 sensory softness.
The
best retail 1-ply BRT prototype containing 80% Southern HW and 20% Southern
SW, at 20.5 lb basis weight and 450 GMT, achieved a 16.9 sensory softness.
The objects included determining: the process requirements that produce
1-ply retail tissue with a sensory softness of 17.0 using Southern hardwood
(HW)
and softwood (SW); the process requirements that produce 1-ply commercial
tissue with a sensory softness of 17.0 using HW and recycled fiber and the
effects
of fiber and other process variables on sensory softness and physical
properties.
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The commercial 1-ply BRT sensory softness objective of 17.0 was
achieved at 20 lb basis weight. Consumer testing will determine the effect of
reduced basis weight on consumer acceptance of the product.
5 Using Southern HW and SW to make 1-ply retail tissue at 21.4 lb/3000
sq.
ft., the highest sensory softness achieved at 450 GMT was 16.9.
Using Southern HW and SW to make 1-ply retail tissue at 20.5 lb/3000 sq.
ft., the highest sensory softness achieved at 450 GMT was 16.9.
Using 40% HW and 60% recycled fiber (FRF) to make 1-ply commercial
tissue at 20.2 lb/3000 sq. ft., the highest sensory softness achieved at 450
GMT
was 17.5. For all work reported here, the average sensory softness was 16.9.
Using 100% FRF to make 1-ply commercial tissue PS at 22.1 lb/3000 sq. ft., the
highest sensory softness achieved at 450 GMT was 16.4.
Using Aracruz HW and Marathon SW to make 1-ply retail tissue at 19.8
lb/3000 sq. ft., the highest sensory softness achieved at 450 GMT was 18.3.
For
all work reported here, the average sensory softness was 18Ø
Steel/steel calendering resulted in higher caliper reduction at equivalent
load and higher sensory softness than rubber/steel calendering.
Increasing calender load appeared to increase sensory softness, but
calendering at higher than 65 PLI may decrease softness when using virgin HW
and recycled fiber. For HW and SW, 80 PLI may be the upper limit.
At constant line crepe percent, an increase in fabric crepe percent resulted
in an increase in CD stretch and a reduction in CD break modulus. However,
finished product sensory softness was not affected at constant GMT.
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At constant line crepe percent, varying the amounts of fabric crepe percent
versus reel crepe percent did not affect sensory softness.
The types of creping fabrics used in this study affected basesheet caliper,
but did not significantly affect sensory softness. Coarse mesh fabrics
developed
higher basesheet caliper and allowed for higher calendering levels.
1-ply BRT with a 1.0 MD/CD tensile ratio (MD tensile equal to CD
tensile) was equivalent in sensory softness to 1-ply BRT with a traditional
MD/CD ratio of 1.8 (higher MD tensile). In this case, softness was dependent
on
GMT not CD strength or CD modulus.
= Furnish Effect
The fiber mixtures in Tables 3 and 4 were run at similar process conditions
and 1-ply BRT was produced. Sensory softness was measured and adjusted to
450 GMT using the strength ¨ softness values from data in the Appendix with
the
formula: (sensory softness) + ((450 ¨ GMT) * (-0.0035)). The eucalyptus and
Marathon SW furnish resulted in significantly higher softness than the others.
The Southern HW and SW furnish is currently being used for retail 2-ply
tissue.
It is the furnish currently used in the development of 1-ply BRT prototypes on
PM#2. Replacing the Southern SW with Marathon SW slightly improved softness
(first table). To date, 16.9 is the best sensory softness achieved at 450 GMT
(second table). The average for all work containing only Southern fiber is
16.4.
Achieving the 17.0 sensory softness target at 450 GMT represents a significant
technical challenge. The fabric crepe process of the invention produces a very
low modulus sheet that is acceptable for retail or commercial BRT. However,
because the sheet is attached to the Yankee with a fabric, there is less
contact area
on the dryer. During the Yankee creping process, less smoothing of the sheet
surface occurs compared to conventional attachment to the Yankee with a felt.
This results in a flannel-like feel compared to the silky feel of conventional
creping. The airside of the sheet, as in conventional wet-press creping, is
less
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r
smooth than the dryerside. In a 1-ply product the airside contributes to
overall
softness, since it cannot be hidden to the inside as in a 2-ply product. This
combination results in a lower sensory softness rating. The current approach
to
improving softness is to build caliper with a relatively coarse creping
fabric, add a
softening agent and calender with "high" load to smooth the sheet and reduce
two-
sidedness. The tissue (commercial) furnish, for 1-ply BRT, will be 40%
Northern
HW and 60% recycled fiber. In the table below, FRF is Fox River recycled wet-
lap. FRF is a high brightness recycled fiber. With only a few data points,
17.5
sensory softness is the best so far. The average, thus far, is 16.9. Here the
17.0
softness target will be less of a challenge. All of the data in the tables
below are
for a blended basesheet. HW and SW were usually made in separate pulpers and
run from different chests. The fibers are usually blended at the fan
pumps creating a homogenous blend of fiber.
Table 3
Furnish Softness Adjusted to 450 GMT
80%EUC/20%MAR 17.6
80%SHW/20%MARSW 16.9
40%NHW/60%FRF 16.8
100% FRF 16.4
80%SHW/20%SSW 16.4
Table 4
Highest Softness Adjusted to
Furnish 450 GMT
80%EUC/20%MAR 18.3
40%NHW/60%FRF 17.5
80%SHW/20%SSW 16.9
80%SHW/20%MARSW 16.9
100% FRF 16.4
(
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Rubber/Steel Calendering
To reduce the two-sidedness of 1-ply BRT, a rubber roll and a
conventional steel calender roll were compared to conventional steel/steel
calendering. The rubber roll was placed against the dryerside of the sheet.
Tables 5-7 below show the effect of calender load on basesheet caliper using
rubber rolls of different hardness's. Both rubber rolls gave similar levels of
caliper reduction for equivalent calender load. The steel/steel rolls gave
significantly higher caliper reduction at equivalent load as seen in the chart
below.
The 56 P+J roll, which is harder than the (nominal) 80 P+J roll, should have
given
more caliper loss at equivalent load. The (nominal) 80 P+J roll had been used
previously and its actual measured P+J value was 70. Its cover thickness was
5/8
inches compared to 1 inch for the 56 P+J roll. The calculated nip width for a
70
P+J roll with a 5/8-inch'cover thickness is slightly less than for the 56 P+J
roll
with a 1-inch cover. This explains the higher caliper reduction seen with the
"80
P+J" roll.
Table 5
Calender Calender 8 Sheet Caliper
Type Load, PLI Caliper, mils* Reduction, %
80 P+J/Steel 0 88.5
80 P+J/Steel 25 77.5 12.4
80 P+J/Steel 55 71.1 19.7
80 P+J/Steel 80 67.1 24.2
80 P+J/Steel 100 64.4 27.2
* 21 lb basesheet
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Table 6
Calender Calender 8 Sheet Caliper
Type Load, PLI Caliper, mils* Reduction, %
56 P+J/Steel 0 89.4
56 P+J/Steel _ 25 80.0 11.7
56 P+J/Steel 50 75.7 15.4
56 P+J/Steel 50 75.9 15.1
56 P+J/Steel 80 72.4 18.9
56 P+J/Steel 80 73.2 18.1
56 P+J/Steel 100 72.9 18.4
56 P+J/Steel _ 200 65.9 26.3
56 P+J/Steel 200 65.6 26.6
* 23 lb basesheet
Table 7
Calender Calender 8 Sheet Caliper
Type Load, PLI Caliper, mils* Reduction, %
Steel/Steel 0 86.1
Steel/Steel 25 69.4 19.3
Steel/Steel 25 72.8 15.4
Steel/Steel 50 61.4 28.7
Steel/Steel 50 61.8 28.2
Steel/Steel 80 55.5 35.5
Steel/Steel 100 54.7 36.4
Steel/Steel 200 49.5 42.4
* 23 lb basesheet
As calendering load increased, two-sidedness was significantly reduced for
all types of calender rolls. However, the sheets calendered with rubber/steel
rolls
did not feel as soft as steel/steel calendered basesheets. Figure 9 shows that
at a
given GMT, sensory softness is about 0.4 softness units higher for steel/steel-
calendered sheets.
Several basesheets were calendered at different loads using the steel/steel
rolls. The calendering station is located before the reel on the paper
machine.
These basesheets were then embossed during converting into 1-ply BRT. The
chart below shows that there is little effect due to calender load on sensory
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softness for sheets that contained premium fiber, i.e. eucalyptus HW and
Marathon SW. For the sheets containing Northern HW and Fox River Secondary
Fiber, softness improved at 65 PLI calender load, but decreased when calender
load was increased to 80 PLI. The Southern sheets increased in softness
slightly
5 as calender load increased. Variable process conditions and different
emboss
patterns make it difficult to quantify the calendering effect on softness.
However,
it appears that some calendering improves softness, but over-calendering
degrades
softness.
10 Spray Softener Comparison
Hercules D1152, TQ456 and TQ236 were compared as spray softeners
added to the airside of the sheet. The table below shows the results. When
adjusted for GMT, there was no difference in softness between the softeners.
Hercules M-5118 was also tried as a spray softener. This material is a
15 polypropylene glycol ether, as is known in the art. However, when it was
sprayed
on the airside of the sheet at 2 lb/T, while the sheet was on the 4-foot dryer
(transfer cylinder, Figure 3), the sheet would not stick to the creping
fabric.
When the spray was placed on the dryerside of the sheet, either on the felt
before
the suction turning roll (STR) or on the creping fabric before the solid
pressure
20 roll (SPR), the sheet would not stick to the 4-foot dryer or the Yankee
dryer,
respectively. The other softeners did not result in adhesion problems and did
not
adversely affect Yankee coating at 2 lb/T. However, at 4 lb/T and higher, all
resulted in unstable Yankee coatings. Results appear in Table 8.
25 Table 8
Sensory Softness
Emboss Calender Spray Softener, at 450 GMT
Pattern Rolls Softener lb/T
'819 80P+J/Steel TQ236 2 16.1
'819 80P+J/Steel D1152 2 16.1
'819 56P+J/Steel D1152 2 16.2
'819 56P+J/Steel TQ456 2 16.1
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Wet-End Softener Comparison
The wet-end addition of softeners to the thick stock (usually the HW) at
levels up to 16 lb/T was possible without creating Yankee coating instability.
The
table below shows a comparison of Hercules TQ236, TQ456, D1152 and
Clearwater*CS359. All were made under similar process conditions. The
steel/steel calender rolls were loaded at 50 PLI. The '819 emboss pattern was
used for converting. At equivalent addition rates and GMT, all of the
softeners
performed the same. In the case where refining was increased to compensate for
the increase in softener, which acts as a debonder, no softness improvement
was
seen. In this case only the Southern SW was refined and softener added only to
the Southern HW. This was a test of the "few but strong bonds" theory. By
refining only the SW for strength, a greater amount of softener could then be
added to the IIW to theoretically improve softness. Refining only the SW (20%
of the sheet) did not result in a softer sheet. Although unconfirmed by the
Sensory
Panel, D1152 was chosen as the softener of choice primarily based on
subjective
evaluation of softness. Results are summarized in Table 9.
Table 9
Sensory
Refiner, Calender, Wet-end
Furnish Softener, lb/T Softness,
HP PLI Softener
450 GMT
SHW/SW NO load 50 TQ236 4.0 16.5
SHW/SW 46 50 TQ236 8.0 16.4
SHW/SW 42 50 TQ456 16.0 16.6
SHW/SW 43 50 D1152 4.5 16.2
SH HW/SW 43 50 D1152 7.5 16.4
SHW/SW _ 43 50 D1152 9.0 16.8
SHW/SW No load 50 CS359 4.0 16.3
NHW/FRF No load 80 D1152 8.0 16.8
Emboss Pattern Effect
Different emboss patterns were used to determine if a particular pattern
interacted with the fabric creped basesheet to produce high softness. Past
studies
*Trade mark
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have shown that most emboss patterns do not improve basesheet softness other
than by strength degradation. In most cases process conditions were similar
but
not constant for the comparisons that follow. However, they were similar
enough
to determine if a significant softness improvement had occurred. The tables
below show that no significant softness improvement can be attributed to any
of
the patterns tested. The "Double Hearts," "819" ( United States Patent No. 6,
827,819) and "Butterflies and Swirls" patterns appear to give equivalent
sensory
softness. See Tables 10-13 below. Directionally, the "Mosaic Iris" pattern
gave
higher sensory softness values than the "Butterflies and Swirls with Micro"
pattern. Based on this limited data, the "Butterflies and Swirls with Micro"
pattern is not recommended for the fabric creped basesheet. "M3" and "Mosaic
Iris" emboss patterns gave equivalent softness values, and should be
considered
equivalent, to those in Table 10 for constant furnish and GMT.
Table 10 - Southern HW/Southern SW
Softness at
Emboss Pattern GMT Sensory Softness 450 GMT
Double Hearts 493 16.4 16.6
819 399 16.6 16.4
Butterflies and
Swirls 454 16.3 16.3
Butterflies and
Swirls 421 16.4 16.3
819 417 16.4 16.3
819 420 16.3 16.2
819 403 16.3 16.1
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Table 11 - 40% Northern HW/60% Fox River Recycled Fiber (FRF)
Softness at 450
Emboss Pattern GMT Sensory Softness GMT
Mosaic Iris 439 17.5 17.5
Butterflies and Swirls,
Micro 376 17.3 17.0
Table 12 - 40% Eucalyptus HW/60% Fox River Recycled Fiber (FRF)
Softness at
Example Emboss Pattern GMT Sensory Softness 450 GMT
255 Mosaic Iris 477 17.6 17.7
Butterflies and
254 Swirls, Micro 451 17.0 17.0
Butterflies and
256 Swirls, Micro 419 17.0 16.9
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Table 13 - Eucalyptus HW / Marathon SW
Softness at
Example Emboss Pattern GMT Sensory Softness 450 GMT
271 M3 428 18.6 18.5
271 M3 584 17.8 18.3
257 Mosaic Iris 507 18.1 18.3
Butterflies and
259 Swirls, Micro 478 17.9 18.0
Butterflies and
258 Swirls, Micro 454 18.0 18.0
Fabric Crepe Versus Reel Crepe
Basesheet was produced at constant line crepe, but with a wide range of
fabric crepe percents. Line crepe or overall crepe is calculated by dividing
transfer cylinder speed (also appx forming speed) by reel speed. From this
value,
1 is subtracted. The resulting value is multiplied by 100 and is expressed as
percent. For fabric crepe, transfer cylinder speed is divided by Yankee speed,
because this is also the creping fabric speed, and then 1 is subtracted and
multiplied by 100. For reel crepe, the Yankee speed is divided by the reel
speed
and then 1 is subtracted and multiplied by 100. Generally, the transfer
cylinder
speed and reel speed were held constant and Yankee speed varied to create the
different fabric/reel crepe conditions. Basesheet data shows that the highest
MD
stretch occurred at the highest reel crepe. The lowest geometric mean (GM)
break
modulus and highest CD stretch occurred at the highest fabric crepe. None of
the
sheets presented any runnability problems. Other than Yankee speed, other
process variables were held constant with the exception of Yankee coating
addition, which was increased for Example 56. In terms of physical properties,
the sheets were remarkably similar for the extreme range of fabric/reel crepe
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conditions employed. Results are summarized in Table 14. For these trials, the
transfer cylinder was a 4-foot diameter dryer.
Table 14
5
Basesheet
Example 56 54 55 57
4' Dryer Speed 2401 2403 2400 2399
Yankee Speed 2200 1800 1530 1400
Reel Speed 1423 1402 1399 1400
Fabric Crepe, % 9 34 57 71
Reel Crepe, % 55 28 9 0
Line Crepe, % 69 71 72 71
Basis Weight 24.2 23.3 24.5 24.0
8 Sheet Caliper 72.6 73.4 74.0 70.9
MD Tensile 569 510 545 499
MD Stretch 68.4 59.3 62.3 59.7
CD Tensile 676 617 682 610
CD Stretch 6.4 6.0 6.8 8.4
GM Tensile 620 561 608 552
MD/CD Ratio 0.84 0.83 0.80 0.82
GM Break Mod 29 30 29 25
MD Break Mod 8 9 9 8
CD Break Mod 101 103 99 73
All sheets were converted into finished 1-ply BRT rolls using either no
emboss pattern or a pattern as described in United States Patent No.
6,827,819.
10 Physical data seen in the Tables 15 and 16 below was very similar to the
basesheet
data from above. The sheets with all fabric crepe and no reel crepe (Ex. 57)
had
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significantly higher CD stretch and lower CD break modulus. GM modulus was
directionally lower. However, sensory softness data indicated no softness
advantage for-any of the sheets.
. 5 /
Table 15
Converted, '819 Pattern
Example 212 208 210 214
Fabric Crepe, % 9 34 57 71
Reel Crepe, % 55 28 9 0
Line Crepe, % 69 71 72 71
Sensory Softness 16.2 16.1 15.9 16.2
Basis Weight 20.7 20.7 22.1 21.7
8 Sheet Caliper 75.8 73.7 76.4 72.9
MD Tensile 505 457 498 444
MD Stretch 36.8 37.7 40.0 38.6
CD Tensile 447 446 514 427
CD Stretch ' 6.8 6.7 6.7 7.8
GM Tensile 475 451 506 435
MD/CD Ratio 1.13 1.03 0.97 1.04
GM Break Mod 30.1 28.5 30.9 25.1
MD Break Mod 13.7 12.1 12.5 11.5
CD Break Mod 66.1 67.1 76.5 54.9
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Table 16
No Emboss
Example 211 207 210 213
Fabric Crepe, % 9 34 57 71
Reel Crepe, % 55 28 9 0
Line Crepe, % 69 71 72 71
Sensory Softness 15.4 15.8 15.2 15.7
Basis Weight 22.6 22.6 23.4 24.2
8 Sheet Caliper 70.1 68.7 67.3 67.0
MD Tensile 567 493 496 536
MD Stretch 50.8 46.6 45.4 47.5
CD Tensile 561 559 628 583
CD Stretch 5.0 5.5 6.0 6.9
GM Tensile 564 525 558 559
MD/CD Ratio 1.01 0.88 0.79 0.92
I
GM Break Mod 35.3 32.8 33.8 30.9
MD Break Mod 11.1 10.6 10.9 11.3
CD Break Mod 111.9 101.7 104.9 84.4
Creping Fabric Effect
Various creping fabric designs were used to produce basesheets for
converting into 1-ply BRT. Table 17 below shows basesheet data under similar
process conditions. In the crepe fabric type row, the MD and CD filament
counts
are shown as 42X31, for example. The MD count is shown first. MD or CD
refers to the longest knuckle on the side of the fabric against the sheet. M,
G and
B refer to weave styles. The highest uncalendered caliper was achieved with
the
56X25 mesh fabrics. This allowed for higher levels of calendering while still
achieving the target roll diameter and firmness in converted product. Higher
levels of calendering should reduce two-sidedness and may improve softness.
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Table 17
Basesheet
Crepe Fabric 44G, CD 56X45M, 56X25G, 56X25G,36X32B, 56X25M,
Type (42X31) MD MD CD MD CD
Basis Weight,
Uncalendered 23.9 24.2 23.8 24.5 24.2
8 Sheet Caliper,
Uncalendered 87 91 102 _103 98
Calender, PLI 20 50 80 _80 50 50
Basis Weight,
Calendered 23.2 24.0 23.0 23.7 23.0 21.3
8 Sheet Caliper,
Calendered 78.7 63.9 63.9 67.6 68.1 63.6
When converted using the '819 pattern, the 56X25G sheets, at 80 PLI
calendering, had directionally higher sensory softness
MD/CD Tensile Ratio Effect
The fabric crepe process has the ability to easily control MD/CD tensile
ratio over a much wider range than conventional wet-press and TAD processes.
Ratios of 4.0 to 0.4 have been produced without pushing the process to its
limits.
Traditionally, tissue products required that MD tensile be higher than CD
tensile
to maximize formation. For maximum softness, CD tensile was kept as low as
possible. This increases the risk of failure in use by consumers. If CD
tensile
could be increased and MD tensile decreased, GMT would remain constant.
Therefore, at equivalent overall strength there would be less chance of
failure.
The table below shows 1-ply finished BRT data for two separate trials in which
MD/CD tensile ratio was varied. Compare examples 90, 89 107 and 108 in Table
18 below. Reducing the MD/CD ratio increased both CD and GM modulus.
However, sensory softness was not significantly affected when GMT was
accounted for. CD strength was increased by about 100 grams/3 inches. This
should greatly reduce the risk of failure in use. The stretchy nature of the
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basesheet could prevent breaks due to low strength. For high-speed commercial
operation, perf blade type may need to be changed to accommodate low strength
and high stretch.
Table 18
80%EUC 80 AEUC 70%NAHHW 70%NAHHW
Furnish 20%MAR 20%MAR 30%NAHSW 30%NAHSW
Example 90 89 107 108
MD/CD 1.78 1.18 1.37 0.91
Sensory Softness 18.2 17.7 16.3 16.4
Softness at 450 GMT 17.9 17.6 16.1 16.3
GMT 371 427 403 417
BW 20.3 20.2 20.3 20.4
Caliper 63.3 65.9 67.0 67.8
MD Tensile 494 463 471 397
CD Tensile 278 393 345 438
MD Stretch 25.0 24.4 37.6 34.1
CD Stretch 7.8 5.9 8.7 7.1
MD Break Mod 19.8 19.0 12.6 11.7
CD Break Mod 35.9 67.0 39.8 61.1
GM Break Mod 26.6 35.7 22.4 26.7
Southern HW Level
The effect of Southern HW level on sensory softness is shown in Table 19
below. No softness improvement at 75% HW was observed. In both cases
softness was well below the target of 17Ø The 80 P+J rubber/steel
calendering
rolls were used.
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Table 19
Example Emboss Southern HW, Sensory Softness at
Pattern 450 GMT
196 '819 75 16.2
200 '819 50 16.1
Fabric Crepe Versus Spray Softener
5 Process variables were manipulated to determine which, if any, would
result in a finished product sensory softness of 17.0 using Southern HW and
SW.
One such comparison was between a basesheet with no spray softener using high
fabric crepe to control strength and low fabric crepe using spray softener to
control strength. Table 20 shows that softness was equivalent when adjusted
for
10 GMT. In both cases softness was well below the target of 17Ø The 80
P+J
rubber/steel calendering rolls were used.
Table 20
PM#2 Emboss Spray Fabric Sensory Softness
Roll # Pattern Softener, lb/T Crepe, % at 450 GMT
200 '819 2 31 16.1
198 '819 0 56 16.1
15 Molding Box Vacuum
The molding box was located on the creping fabric, between the crepe roll
and the solid pressure roll. Sheet solids were usually between 38 and 44% at
this
point. The effect of vacuum on sheet caliper can be seen in the table. An
increase
of almost 8 mils of "8-sheet caliper" was observed with 21 inches of mercury
20 vacuum at the molding box. This is about a 14% increase. Both rolls were
calendered at 50 PLI with steel/steel rolls. The amount of caliper development
is
dependent on the coarseness of the fabric weave and the amount of vacuum
applied. Other sheet properties were not significantly affected. Drying was
affected by use of the molding box. Without a significant change in Yankee
hood
25 temperature, sheet moisture after the Yankee increased from 2.66 to
3.65%.
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Vacuum pulls the sheet deeper into the creping fabric, therefore, there is
less
contact with the Yankee and more drying is required to maintain sheet
moisture.
See Table 21. In this case the Yankee hood temperatures were not adjusted.
Table 21
Creping Molding Box 8 Sheet Scanner Sheet
Fabric Vacuum, in. Caliper, mils Moisture, %
Hg
44G 0 56.7 2.66
44G 21 64.6 3.65
Effect of Sheet Moisture, at Fabric Crepe, On Basesheet Properties
By manipulating process variables, sheet moisture coming into the fabric
creping part of the process can be varied. On the papermachine employed,
equiped with a 120mm shoe-press and 22 lb sheet, solids could be varied from
about 34 to 46%. For the low solids condition, STR vacuum was reduced, shoe-
press load was reduced and 4-foot dryer steam reduced. To dry this sheet to
about
2% moisture at the reel, Yankee steam and hood temperature had to be
increased.
The low solids basesheet was about 270 grams/3 in. lower in GMT than the high
solids sheet. See the table below. This was primarily due to the lower
compaction that takes place at lower shoe-press loading. The fabric creping
step
rearranged the fibers to a great extent, but apparently it was not able to
completely
undo all of the compaction of pressing. Other physical properties, including
SAT
capacity, were not significantly different when the strength difference was
taken
into account. This experiment should be repeated at constant pressing by using
only vacuum and steam to alter sheet solids. However, based on this
experiment,
the effect of sheet solids on basesheet properties in the range studied here
is not
expected to be significant. The drying impact is significant and it would be
worthwhile to expand the range of solids tested. Results are summarized on
Table
22 below.
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Table 22
"Low" Solids "High" Solids
Fabric Creping Fabric Creping
Example 94 95
Sheet Solids Before Fabric Creping 33.8 46.1
Yankee Hood Temperature 950 550
Yankee Steam PSI 110 105
Suction Turning Roll Vacuum 7.9 13.1
Shoe-press Load, PLI 200 500
4-Foot Dryer Steam 25 70
BW 22.3 22.8
Caliper 91.2 85.2
MD Tensile 976 1236
MD Stretch 52.2 53.7
CD Tensile 1205 1481
CD Stretch 5.8 5.6
GMT 1084 1353
MD/CD 0.81 0.83
GM Break Mod 61 78
CD Break Mod 205 261
MD Break Mod 18 24
SAT Capacity 190 168
