U.S. patent application number 13/804005 was filed with the patent office on 2013-09-19 for methods of measuring a characteristic of a creping adhesive film and methods of modifying the creping adhesive film.
This patent application is currently assigned to KEMIRA OYJ. The applicant listed for this patent is KEMIRA OYJ. Invention is credited to Vladimir Grigoriev, Chen Tampa Lu, Danny Nguyen, Scott Rosencrance.
Application Number | 20130245158 13/804005 |
Document ID | / |
Family ID | 49158210 |
Filed Date | 2013-09-19 |
United States Patent
Application |
20130245158 |
Kind Code |
A1 |
Grigoriev; Vladimir ; et
al. |
September 19, 2013 |
METHODS OF MEASURING A CHARACTERISTIC OF A CREPING ADHESIVE FILM
AND METHODS OF MODIFYING THE CREPING ADHESIVE FILM
Abstract
Described herein are quartz crystal microbalance (QCM) and
quartz crystal microbalance with dissipation (QCMD) techniques that
can be used for measuring characteristics of a creping adhesive
film similar to the creping adhesive film that is formed on a
Yankee dryer during the tissue and towel manufacturing process. In
addition, exemplary embodiments described herein may use these
techniques to predict performance of creping aids utilized to form
a creping adhesive film.
Inventors: |
Grigoriev; Vladimir;
(Atlanta, GA) ; Nguyen; Danny; (Norcross, GA)
; Rosencrance; Scott; (Douglasville, GA) ; Lu;
Chen Tampa; (Marietta, GA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KEMIRA OYJ |
Helsinki |
|
FI |
|
|
Assignee: |
KEMIRA OYJ
Helsinki
FI
|
Family ID: |
49158210 |
Appl. No.: |
13/804005 |
Filed: |
March 14, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61612645 |
Mar 19, 2012 |
|
|
|
Current U.S.
Class: |
523/400 ;
73/579 |
Current CPC
Class: |
G01N 2291/0426 20130101;
G01N 2291/0237 20130101; G01N 29/036 20130101; G01H 13/00
20130101 |
Class at
Publication: |
523/400 ;
73/579 |
International
Class: |
G01H 13/00 20060101
G01H013/00 |
Claims
1. A method of measuring a characteristic of a creping adhesive
film, comprising: disposing a creping adhesive film on a sensor
substrate; measuring an oscillation frequency of the sensor
substrate having the creping adhesive film disposed thereon using a
Quartz Crystal Microbalance (QCM) technique; and determining a
characteristic of the creping adhesive film.
2. The method of claim 1, further comprising: measuring an
oscillation frequency dissipation of the sensor substrate after the
driving potential is removed from the sensor substrate.
3. The method of claim 1, further comprising: exposing the sensor
substrate to a humid environment, wherein the creping adhesive film
absorbs water from the humid environment; and measuring an
oscillation frequency of the sensor substrate using a QCM
technique.
4. The method of claim 3, further comprising: measuring an
oscillation frequency dissipation of the sensor substrate after the
driving potential is removed from the sensor substrate.
5. The method of claim 1, further comprising: disposing a quantity
of water onto the creping adhesive film, wherein the creping
adhesive film absorbs the water; and measuring an oscillation
frequency of the sensor substrate using a QCM technique.
6. The method of claim 5, further comprising: measuring an
oscillation frequency dissipation of the sensor substrate after the
driving potential is removed from the sensor substrate.
7. The method of claim 1, wherein the characteristic is selected
from the group consisting of: percent solubility, percent
insolubility, rewet ratio, swelling ratio, film viscosity, film
elasticity, film softness, film rigidity, shear modulus, and a
combination thereof.
8. The method of claim 1, wherein measuring an oscillation
frequency includes measuring at two or more frequencies that are
applied to the sensor substrate.
9. The method of claim 1, wherein exposing the sensor substrate
includes exposing the sensor substrate at a first temperature,
wherein the first temperature is a temperature of about 10 to
100.degree. C.
10. The method of claim 9, further comprising: measuring an
oscillation frequency of the sensor substrate at two or more
temperatures using the QCM technique.
11. The method of claim 1, wherein the creping adhesive film
includes one or more creping adhesives.
12. The method of claim 11, wherein the creping adhesive film
includes a component selected from the group consisting of: a
release aid, a modifier, a plasticizer, a humectant, a phosphate, a
creping additive, and a combination thereof.
13. The method of claim 11, wherein the creping adhesive film
includes a component selected from the group consisting of: a
mineral, a hemicellulose, a fiber, a fine, a fiber fragment, and a
combination thereof.
14. The method of claim 11, wherein the creping adhesive film
includes a component selected from the group consisting of: a
softener, a debonder, a defoamer, a wet strength resin, a dry
strength resin, a charge control agent, a retention aid, a biocide,
a dye, and a combination thereof.
15. The method of claim 1, wherein the QCM technique includes
Quartz Crystal Microbalance with Dissipation (QCMD).
16. A method for modifying the creping adhesive film disposed on a
Yankee dryer, comprising: obtaining a sensor substrate having a
creping adhesive film disposed thereon, wherein the creping
adhesive film has a composition that is the same as a creping
adhesive film disposed on a Yankee dryer; measuring an oscillation
frequency of the sensor substrate having the creping adhesive film
disposed thereon using a Quartz Crystal Microbalance (QCM)
technique; determining a characteristic of the creping adhesive
film; and modifying a composition of the creping adhesive film
disposed on the Yankee dryer based on the determination of the
characteristic.
17. The method of claim 16, wherein the characteristic is selected
from the group consisting of: percent solubility, percent
insolubility, rewet ratio, swelling ratio, film viscosity, film
elasticity, film softness, film rigidity, shear modulus, and a
combination thereof.
18. The method of claim 16, wherein the creping adhesive disposed
on the sensor is obtained from a device that provides the
components of the creping adhesive film to the Yankee dryer.
19. The method of claim 16, further comprising: determining how to
adjust one or more components of the composition of the creping
adhesive film to achieve adjustment of a characteristic of the
creping adhesive film.
20. The method of claim 19, wherein the components are selected
from the group consisting of: a creping adhesive, a release aid, a
modifier, a plasticizer, a humectant, a phosphate, a creping
additive, a mineral, a hemicellulose, a fiber, a fine, a softener,
a debonder, a defoamer, a wet strength resin, a dry strength resin,
a charge control agent, a retention aid, a biocide, a dye, and a
combination thereof; and wherein the characteristic is selected
from the group consisting of: percent solubility, percent
insolubility, rewet ratio, swelling ratio, film viscosity, film
elasticity, film softness, film rigidity, shear modulus, and a
combination thereof.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to U.S. provisional
application entitled "METHODS OF MEASURING A CHARACTERISTIC OF A
CREPING ADHESIVE FILM AND METHODS OF MODIFYING THE CREPING ADHESIVE
FILM," having Ser. No. 61/612,645, filed on Mar. 19, 2012, which is
entirely incorporated herein by reference.
BACKGROUND
[0002] 1. Field of the Art
[0003] The present embodiments relate to measuring creping adhesive
film characteristics.
[0004] 2. Description of Related Art
[0005] A conventional creping process generally includes scraping a
dried paper web from a drying cylinder (e.g., a Yankee dryer), such
as by the use of a creping doctor blade. The creping action puts
very small folds or accordions in the sheet which impart a fine,
rippled texture to the sheet, which can increase the bulk, softness
and absorbency of the sheet.
[0006] Adhesion of the sheet to the drying cylinder is one factor
that contributes to how the sheet crepes at the doctor blade. Sheet
adhesion may be controlled through application of an adhesive
formulation onto the Yankee dryer surface. The creping process
typically involves applying the creping adhesive, such as in the
form of an aqueous solution or dispersion, to a drying surface for
the web. Typically, this surface is the surface of a rotating
heated creping cylinder, such as the Yankee dryer. The paper web is
then adhered to the indicated surface and later dislodged from the
surface with a creping device, e.g., a doctor blade. The impact of
the web against the creping device ruptures some of the
fiber-to-fiber bonds within the web, causing the web to wrinkle or
pucker. In this regard, fibrous webs, particularly paper webs, are
conventionally subjected to the creping process in order to give
them desirable textual characteristics, such as softness and bulk.
Adhesive formulations can improve product quality and control of
the papermaking process.
[0007] Drying cylinders such as the Yankee dryer are often operated
at a variety of temperature conditions, for example, ranging from
about 90.degree. C. to 130.degree. C. Recent trends have the
creping conditions moving towards high temperature and/or low sheet
moisture. Under high temperature conditions, "rewettability" of the
applied adhesive may affect adhesion of the sheet to the Yankee
dryer. Rewettability refers to the ability of a dry adhesive film
on the dryer to absorb water, e.g., once in contact with the wet
paper sheet. The adhesive is typically sprayed on the Yankee
coating continuously. However, the majority of the adhesion occurs
by means of the adhesive deposited in previous passes. If the
adhesive absorbs greater amounts of water in contact with the
sheet, the adhesive will be softer, resulting in a more intimate
contact with the sheet and providing increased adhesion between the
sheet and the dryer.
[0008] The solubility of the adhesive film in water is another
property affecting adhesion. The wet sheet before the Yankee dryer
typically contains 60% or more water. During the contact between
the wet sheet and the Yankee dryer, water from the sheet may wash
off a portion of the deposited adhesive coating, which can decrease
the efficiency of the creping process. It is often desirable to use
an adhesive with low water solubility (high insolubility) so that
the adhesive film can withstand wash-off at the point of contact
with the wet sheet, and form a more durable coating on the Yankee
surface.
[0009] Predicting performance of creping adhesives on a commercial
machine is a challenging task, in part because of the extremely
dynamic nature of the creping process. The primary indicator of
performance of creping adhesives has been an adhesion test. The
peel adhesion test is a common laboratory technique for
characterizing adhesion of creping adhesives.
[0010] Adhesion is a complex phenomenon that can be affected by
various parameters. In a common process, the adhesion development
starts in the pressure roll nip at the point of the sheet transfer
from the carrying fabric or felt onto the Yankee dryer cylinder.
The moisture from the wet sheet can rewet the partially or
completely dried adhesive coating, making it soft and pliable
enough to form a good contact with the sheet but ideally not too
soft that it is washed off the Yankee dryer surface. Water is an
effective plasticizer of the creping adhesive film, and can affect
the adhesive film softness. The rewet phenomenon affects the
adhesion development. At the same time water can solubilize the
adhesive film, and potentially render it useless and inefficient. A
certain level of insolubility is desirable for the adhesion
development. Therefore, characterization of film solubility,
rewetting and softness characteristics can help develop an
understanding of the adhesion development on the Yankee dryer and
for predicting performance of creping adhesives.
[0011] Conventional methods for characterizing rewetting,
solubility and softness characteristics of creping adhesive films
involve preparation of uniform adhesive films, typically of a few
millimeters in thickness. For rewetting and solubility
measurements, the films are immersed into water under controlled
agitation, temperature and time. The mass gain and/or loss of the
films are then calculated to determine the rewet ratio or percent
insolubility. For film softness measurements, films are tested
using a durometer to determine a relative hardness or using a more
sophisticated rheometer. In rheological measurements, the film
undergoes mechanical stress under controlled temperature and stress
rate. The film's resistance to stress is measured to yield shear
modulus, for example, which can be used to characterize the film
softness. The test time for many of these characterizations is
greater than 10 hours, some test times are longer than 40 hours.
Thus, it is difficult to use these tests to make real time
adjustments. In addition, these methods require a preparation of
thick films (a few millimeter thickness); whereas, in comparison
the thickness of typical adhesive films on the Yanke dryer are
about a few micrometers. The wetting and solubilization phenomena
often depend on the thickness of the film and therefore the
correlation of results of conventional test methods to process
conditions may be relatively poor. Another potential downside of
the conventional rewet methods is their use is often limited to
insoluble or only partially soluble adhesive films--for
fully-soluble adhesive films, moisture absorption may compete with
the solubilization process, resulting in a mass loss measurements
rather than a mass gain, typically sought from a rewet
measurement.
[0012] The description herein of certain advantages and
disadvantages of known methods and compositions is not intended to
limit the scope of the present disclosure. Indeed the present
embodiments may include some or all of the features described above
without suffering from the same disadvantages.
SUMMARY
[0013] In view of the foregoing, one or more embodiments include
methods of measuring a characteristic of a creping adhesive film,
methods of modifying the creping adhesive film, and the like
[0014] At least one embodiment provides a method of measuring a
characteristic of a creping adhesive film, including disposing a
creping adhesive film on a sensor substrate, measuring an
oscillation frequency of the sensor substrate having the creping
adhesive film disposed thereon using a Quartz Crystal Microbalance
(QCM) technique, and determining a characteristic of the creping
adhesive film.
[0015] At least one embodiment provides a method for modifying the
creping adhesive film disposed on a Yankee dryer, including
obtaining a sensor substrate having a creping adhesive film
disposed thereon, where the creping adhesive film has a composition
that is the same as a creping adhesive film disposed on a Yankee
dryer, measuring an oscillation frequency of the sensor substrate
having the creping adhesive film disposed thereon using a Quartz
Crystal Microbalance (QCM) technique, determining a characteristic
of the creping adhesive film, and modifying a composition of the
creping adhesive film disposed on the Yankee dryer based on the
determination of the characteristic.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIGS. 1A and 1B graphically illustrate film thickness
profiles calculated from the QCMD test with a flow module.
[0017] FIG. 2 graphically illustrates a film thickness profile
calculated from the QCMD test with a humidity module.
[0018] FIGS. 3A to 3C graphically illustrate correlations between
the % insolubility, rewet ratio, and shear modulus, measured by
conventional and QCMD methods.
[0019] FIGS. 4A to 4F graphically illustrate correlations between
adhesive characteristics measured by QCMD at peel adhesion at two
extreme temperatures.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0020] Before the embodiments of the present disclosure are
described in detail, it is to be understood that, unless otherwise
indicated, the present disclosure is not limited to particular
materials, reagents, reaction materials, manufacturing processes,
or the like, as such can vary. It is also to be understood that the
terminology used herein is for purposes of describing particular
embodiments only, and is not intended to be limiting. It is also
possible in the present disclosure that steps can be executed in
different sequence where this is logically possible.
[0021] Where a range of values is provided, it is understood that
each intervening value, to the tenth of the unit of the lower limit
(unless the context clearly dictates otherwise), between the upper
and lower limit of that range, and any other stated or intervening
value in that stated range, is encompassed within the disclosure.
The upper and lower limits of these smaller ranges may
independently be included in the smaller ranges and are also
encompassed within the disclosure, subject to any specifically
excluded limit in the stated range. Where the stated range includes
one or both of the limits, ranges excluding either or both of those
included limits are also included in the disclosure.
[0022] Unless defined otherwise, all technical and scientific terms
used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which this disclosure belongs.
Although any methods and materials similar or equivalent to those
described herein can also be used in the practice or testing of the
present disclosure, the preferred methods and materials are now
described.
[0023] All publications and patents cited in this specification are
herein incorporated by reference as if each individual publication
or patent were specifically and individually indicated to be
incorporated by reference and are incorporated herein by reference
to disclose and describe the methods and/or materials in connection
with which the publications are cited. The citation of any
publication is for its disclosure prior to the filing date and
should not be construed as an admission that the present disclosure
is not entitled to antedate such publication by virtue of prior
disclosure. Further, the dates of publication provided could be
different from the actual publication dates that may need to be
independently confirmed.
[0024] As will be apparent to those of skill in the art upon
reading this disclosure, each of the individual embodiments
described and illustrated herein has discrete components and
features which may be readily separated from or combined with the
features of any of the other several embodiments without departing
from the scope or spirit of the present disclosure. Any recited
method can be carried out in the order of events recited or in any
other order that is logically possible.
[0025] Embodiments of the present disclosure will employ, unless
otherwise indicated, techniques of chemistry, synthetic organic
chemistry, paper chemistry, and the like, which are within the
skill of the art. Such techniques are explained fully in the
literature.
[0026] The examples are put forth so as to provide those of
ordinary skill in the art with a complete disclosure and
description of how to perform the methods and use the compositions
and compounds disclosed and claimed herein. Efforts have been made
to ensure accuracy with respect to numbers (e.g., amounts,
temperature, etc.), but some errors and deviations should be
accounted for. Unless indicated otherwise, parts are parts by
weight, temperature is in .degree. C., and pressure is at or near
atmospheric. Standard temperature and pressure are defined as
20.degree. C. and 1 atmosphere.
[0027] It must be noted that, as used in the specification and the
appended claims, the singular forms "a," "an," and "the" include
plural referents unless the context clearly dictates otherwise.
Thus, for example, reference to "a support" includes a plurality of
supports. In this specification and in the claims that follow,
reference will be made to a number of terms and phrases that shall
be defined to have the following meanings unless a contrary
intention is apparent.
DEFINITIONS
[0028] As used herein, the terms "paper" or "paper product" (these
two terms can be used interchangeably herein) are understood to
include a sheet material that contains paper fibers, which may also
contain other materials. Suitable paper fibers include natural and
synthetic fibers, for example, cellulosic fibers, wood fibers of
all varieties used in papermaking, other plant fibers, such as
cotton fibers, fibers derived from recycled paper; and the
synthetic fibers, such as rayon, nylon, fiberglass, or polyolefin
fibers. The paper product may be composed only of synthetic fibers.
Natural fibers may be mixed with synthetic fibers. For instance, in
the preparation of the paper product, the paper web, or paper
material may be reinforced with synthetic fibers, such as nylon or
fiberglass, or impregnated with nonfibrous materials, such as
plastics, polymers, resins, or lotions. As used herein, the terms
"paper web" and "web" are understood to include both forming and
formed paper sheet materials, papers, and paper materials
containing paper fibers. The paper product may be a coated,
laminated, or composite paper material. The paper product can be
bleached or unbleached.
[0029] Paper can include, but is not limited to, writing papers and
printing papers (e.g., uncoated mechanical, total coated paper,
coated free sheet, coated mechanical, uncoated free sheet, and the
like), industrial papers, tissue papers of all varieties,
paperboards, cardboards, packaging papers (e.g., unbleached kraft
paper, bleached kraft paper), wrapping papers, paper adhesive
tapes, paper bags, paper cloths, toweling, wallpapers, carpet
backings, paper filters, paper mats, decorative papers, disposable
linens and garments, and the like.
[0030] Paper can include tissue paper products. Tissue paper
products include sanitary tissues, household tissues, industrial
tissues, facial tissues, cosmetic tissues, soft tissues, absorbent
tissues, medicated tissues, toilet papers, paper towels, paper
napkins, paper cloths, paper linens, and the like. Common paper
products include printing grade (e.g., newsprint, catalog,
rotogravure, publication, banknote, document, bible, bond, ledger,
stationery), industrial grade (e.g., bag, linerboard, corrugating
medium, construction paper, greaseproof, glassine), and tissue
grade (sanitary, toweling, condenser, wrapping).
[0031] In an exemplary embodiment, tissue paper may be a felt
pressed tissue paper, a pattern densified tissue paper, or a high
bulk, uncompacted tissue paper. In an exemplary embodiment, the
tissue paper may be creped or uncreped, of a homogeneous or
multilayered construction, layered or non-layered (blended), and
one-ply, two-ply, or three or more plies. In an exemplary
embodiment, tissue paper includes soft and absorbent paper tissue
products that are consumer tissue products.
[0032] "Paperboard" is a paper that is thicker, heavier, and less
flexible than conventional paper. Many hardwood and softwood tree
species are used to produce paper pulp by mechanical and chemical
processes that separate the fibers from the wood matrix. Paperboard
can include, but is not limited to, semi-chemical paperboard,
linerboards, containerboards, corrugated medium, folding boxboard,
and cartonboards.
[0033] In an exemplary embodiment, paper refers to a paper product
such as dry paper board, fine paper, towel, tissue, and newsprint
products. Dry paper board applications include liner, corrugated
medium, bleached, and unbleached dry paper board.
[0034] In an embodiment, paper can include carton board, container
board, and special board/paper. Paper can include boxboard, folding
boxboard, unbleached kraft board, recycled board, food packaging
board, white lined chipboard, solid bleached board, solid
unbleached board, liquid paper board, linerboard, corrugated board,
core board, wallpaper base, plaster board, book bindery board,
woodpulp board, sack board, coated board, gypsum board and the
like.
[0035] "Pulp" refers to a fibrous cellulosic material. Suitable
fibers for the production of the pulps are all conventional grades,
for example mechanical pulp, bleached and unbleached chemical pulp,
recycled pulp, and paper stocks obtained from all annuals.
Mechanical pulp includes, for example, groundwood, thermomechanical
pulp (TMP), chemothermochemical pulp (CTMP), groundwood pulp
produced by pressurized grinding, semi-chemical pulp, high-yield
chemical pulp and refiner mechanical pulp (RMP). Examples of
suitable chemical pulps are sulfate, sulfite, and soda pulps. The
unbleached chemical pulps, which are also referred to as unbleached
kraft pulp, can be particularly used.
[0036] "Pulp slurry" refers to a mixture of pulp and water. The
pulp slurry is prepared in practice using water, which can be
partially or completely recycled from the paper machine. It can be
either treated or untreated white water or a mixture of such water
qualities. The pulp slurry may contain interfering substances
(e.g., fillers). The filler content of paper may be up to about 40%
by weight. Suitable fillers are, for example, clay, kaolin, natural
and precipitated chalk, titanium dioxide, talc, calcium sulfate,
barium sulfate, alumina, satin white or mixtures of the stated
fillers.
[0037] "Papermaking process" is a method of making paper products
from pulp comprising, inter alia, forming an aqueous pulp slurry
that can include a cellulosic fiber, draining the pulp slurry to
form a sheet, and drying the sheet. The steps of forming the
papermaking furnish, draining, and drying may be carried out in any
conventional manner generally known to those skilled in the
art.
General Discussion
[0038] In various exemplary embodiments described herein, quartz
crystal microbalance (QCM) and quartz crystal microbalance with
dissipation (QCMD) techniques can be used for measuring
characteristics of a creping adhesive film similar to the creping
adhesive film that is formed on a Yankee dryer during the tissue
and towel manufacturing process. In addition, exemplary embodiments
discussed herein may use these techniques to predict performance of
creping aids utilized to form a creping adhesive film. Furthermore,
exemplary embodiments of the present disclosure can predict
performance of creping aids utilized to form a creping adhesive
film based on conditions (e.g. temperature, humidity, and the like)
present in tissue and towel manufacturing processes. Additionally,
exemplary embodiments described herein can be used to modify one or
more characteristics of the creping adhesive film in real time to
enhance and improve the tissue and towel manufacturing process.
[0039] The Quartz Crystal Microbalance (QCM) is a mass sensing
device with the ability to measure very small mass changes on a
quartz crystal resonator in real-time. The sensitivity of the QCM
is approximately 100 times higher than an electronic fine balance
with a sensitivity of 0.1 mg. This means that QCM's are capable of
measuring mass changes as small as a fraction of a monolayer or
single layer of molecules. QCM uses a voltage being applied to a
quartz crystal causing it to oscillate at a specific frequency,
where different voltages correspond to different frequencies.
Changes in mass on the quartz surface are related to changes in
frequency of the oscillating crystal through the Sauerbrey
relationship. Further theory and practical aspects of QCM can be
found in Applications of Piezoelectric Quartz Crystal
Microbalances; C. Lu, A. W. Czanderna, ed., Amsterdam: Elsevier
1984, which is incorporated herein by reference.
[0040] The Sauerbrey relation is valid for rigid, evenly
distributed, and sufficiently thin adsorbed layers (e.g., dry
creping adhesive film). However, for soft or viscoelastic films
(e.g., wet creping adhesive film) that do not fully couple to the
oscillating crystal, the Sauerbrey relationship may underestimate
the mass.
[0041] For viscoelastic films, Quartz Crystal Microbalance with
Dissipation (QCMD) may be more appropriate. QCMD measures both
frequency and dissipation of the quartz crystal. Dissipation occurs
when the driving voltage to the crystal is shut off and the energy
from the oscillating crystal dissipates from the system. The
frequency of the oscillating quartz crystal changes with the mass
on the sensor. When molecules adsorb to an oscillating quartz
crystal, water (or other liquid) couples to the adsorbed material
(e.g., the creping adhesive layer) as an additional dynamic mass
via direct hydration and/or entrapment within the adsorbed film.
Thus, the layer is sensed as a viscoelastic "hydrogel" composed of
the molecules and the coupled water. By measuring the dissipation,
one can determine if the adsorbed film is rigid or viscoelastic
(soft), which is not possible looking only at the frequency
response.
[0042] Dissipation measurements enable qualitative analysis of the
structural properties of adsorbed molecular layers. Different
materials can easily be compared and one can ascertain if the
Sauerbrey relation will accurately approximate the adsorbed mass or
not. Furthermore, the QCMD technology allows quantitative analysis
of the mass, thickness, viscosity and complex shear modulus, for
example, of the adsorbed films (e.g., the creping adhesive layer)
whereas these measurements are well beyond the Sauerbrey regime.
This is achieved by combining frequency and dissipation
measurements from multiple harmonics (overtones) and applying
simulations using a Voigt-based viscoelastic model. QCMD enables
real-time measurements of both mass and structural properties of
molecular layers. Measuring the dissipation parameter allows
accurate analysis of soft films that do not obey the linear
relation between change in frequency and change in mass. A basic
explanation of the QCMD technology is found in Energy Dissipation
Kinetics for Protein and Antibody-Antigen Adsorption under Shear
Oscillation on a Quartz Crystal Microbalance in Langmuir 1998, 14,
729-734 by Hook et al, which is incorporated herein by reference.
Interpretation of QCMD data and applying the viscoelastic model is
well described in: Analysis of Interpenetrating Polymer Networks
via Quartz Crystal Microbalance with Dissipation monitoring in
Langmuir. 2005 Jun. 7; 21(12):5529-36 by Irwin et al, which is
incorporated herein by reference.
[0043] In an exemplary embodiment, QCM and/or QCMD techniques can
be used to characterize one or more properties of a creping
adhesive film. Creping adhesive films tend to be rigid when they
are completely dry but when the films absorb moisture they become
soft (viscoelastic). QCM, QCMD, or a combination of thereof can
provide valuable information on the interaction of moisture with
the adhesive films and their viscoelastic characteristics. In an
exemplary embodiment, QCM techniques can be used to measure rigid
films and QCMD techniques can be used to measure soft films. This
information can be used to modify one or more components or
properties of the creping adhesive films, the temperature of the
environment around the creping adhesive films, the humidity of the
environment around the creping adhesive films, or the like, or a
combination thereof.
[0044] In an exemplary embodiment, the creping adhesive film can be
disposed (e.g., cast) on a quartz crystal sensor using any of
various known or later-developed techniques. Exemplary film
deposition techniques include, for example, dip coating,
sputtering, thermal evaporation, spin coating, and/or other
appropriate method. In an exemplary embodiment, the creping
adhesive film can have a thickness of about 1 nanometer to 1000
micrometers, which is consistent with the creping adhesive film
thickness on a Yankee dryer. In an exemplary embodiment, the length
and/or width of the creping adhesive film can vary depending on the
dimensions of the sensor.
[0045] In general, quartz crystal sensors used in QCM and QCMD
techniques are well known in the art. In an exemplary embodiment,
the quartz crystal sensor can have a diameter of about 14 mm and a
thickness of about 0.3 mm. In an exemplary embodiment, the sensor
can have a metal, metal oxide layer, and/or polymer layer disposed
on portions of and/or around the sensor. In an exemplary
embodiment, the metal oxide can include: SiO.sub.2,
Al.sub.2O.sub.3, Ti, Pt, Ag, W, Cu, Cr, Ir, Ta, FeC.sub.3, TaN,
CeO.sub.2, Fe, Zn, ZnO.sub.2, FeO.sub.3, ZnS, FeS, stainless steel,
and the like. In an exemplary embodiment, the polymer can include
PS, PC, PMMA, a fluoropolymer, PE, PP, and the like. In addition,
the quartz crystal sensor includes appropriate contacts to connect
with a device to drive and control the frequency and to measure the
oscillation frequency change. The oscillation frequency data can be
communicated to a device such as a computer, where the data can be
subsequently analyzed and various characteristics determined about
the creping adhesive film.
[0046] In an exemplary embodiment, the creping adhesive film can be
cast on a quartz crystal using a spin coating technique. In an
embodiment, the spin coating technique can be used to form a
thickness of about a few nanometers or less of the creping adhesive
film on the sensor. In an embodiment, these ultrathin films can be
prepared within minutes, significantly accelerating the film
preparation process compared to conventional methods described
above.
[0047] After curing at a high temperature (e.g., about 50 to
150.degree. C.) for a period of time (e.g., for about 60 min, about
30 min, or less), the creping adhesive film can be analyzed using a
QCM and/or QCMD at one or more frequencies. In addition, the
creping adhesive film can be exposed either to a water flow (also
referred to as the flow module in the Example) or humid air (also
referred to as the humidity module in the Example) in a QCM and/or
QCMD chamber and changes in oscillation frequency can be recorded
at one or more frequencies. The frequency data can be further
analyzed using established models. In an exemplary embodiment, the
frequency data can be used to generate one or more characteristics
of the creping adhesive film (e.g., weight change, percent
solubility, rewet ratio, film viscosity, film elasticity, shear
modulus, percent insolubility, swelling ratio, film softness, film
rigidity, and a combination thereof can be calculated), each of
which can be analyzed as a function of moisture exposure (e.g.,
flow module and/or humidity module), temperature (e.g., about 10 to
100.degree. C.), water flow rate, relative humidity (e.g., about 0
to 100%), film preparation conditions (cure time, cure temperature,
film thickness, etc.), and a combination thereof. The variables of
temperature and/or water exposure can be designed to resemble the
actual conditions that the crepe adhesive film is experiencing
during paper processing so modifications can be made in real time
if desired. In an embodiment, film solubility, rewet ratio, weight
change, and/or shear modulus of creping adhesive films can be
measured separately or simultaneously depending on the crepe
adhesive type and the instrument configuration. In an embodiment,
the data and characteristics can be used to predict adhesive
performance and can be used to modify, in real time, the
composition of the components in the creping adhesive layer to
improve the characteristics of the creping adhesive layer.
[0048] In an exemplary embodiment, the method of measuring a
characteristic of a creping adhesive film includes disposing a
creping adhesive film on a sensor substrate using one of the
techniques described herein. One or more frequencies can be applied
to the sensor substrate and the oscillation frequency of the sensor
substrate can be measured using a QCM and/or QCMD technique. The
data acquired can be used to determine one or more characteristics
of the creping adhesive film. In an embodiment, one or more
frequencies can be applied using the QCM and/or QCMD techniques to
the sensor substrate under various conditions (e.g., modification
of the temperature, exposure to humidity (before and after),
exposure to water (before and after), and the like), where the
conditions can be designed to resemble the actual processing
conditions that the creping adhesion film is experiencing during
tissue and towel production.
[0049] The exemplary embodiments may be used to characterize any
creping adhesive. In an embodiment, the creping adhesive film can
be made using one or more of the following components: a creping
adhesive, a release aid, a modifier, a plasticizer, a humectant, a
phosphate, a creping additive, a mineral, hemicellulose, a fiber, a
fine, a fiber fragment, a softener, a debonder, a defoamer, wet
strength resin, a dry strength resin, a charge control agent, a
retention aid, a biocide, a dye, and a combination thereof. In an
embodiment, the creping adhesive can include a polyvinyl alcohol,
polyamine/epihalohydrin resin (e.g., PAE), polyacrylamide,
carboxymethylcellulose, polyvinyl acetate, and the like. Components
to make a creping adhesive film are known in the art. Embodiments
of the present disclosure are not limited by the components of the
creping adhesive film.
[0050] An exemplary embodiment of the present disclosure allows for
the measurement of characteristics of the creping adhesive film as
a function of one or more of the components that are used to make
the creping adhesive film and/or that may become in contact (e.g.,
fibers, chemicals from the pulp slurry, and the like), and possible
part of, the creping adhesive film. In addition, an exemplary
embodiment of the present disclosure provides one of skill in the
art information about the characteristics of the creping adhesive
film so that the amounts and/or types of components of the creping
adhesive film can be modified to achieve desired results. In an
exemplary embodiment, the modification can occur in real time
(e.g., less than about 1 hour) or near real time (e.g., about 1 to
8 hours or about 1 to 4 hours) unlike other methods. In an
exemplary embodiment, the modification can be made prior to being
implemented in the manufacturing process and measured using the QCM
and/or QCMD technique to ensure that the desired characteristics
are realized using the modified creping adhesive film. Thus, an
exemplary embodiment of the present disclosure enables the creping
adhesive film to be designed and tested prior to
implementation.
[0051] As mentioned above, an exemplary embodiment of the present
disclosure includes a method for modifying the creping adhesive
film disposed on a Yankee dryer (e.g., in real time or near real
time). In an exemplary embodiment, the method includes obtaining a
sensor substrate having a creping adhesive film disposed thereon.
In an embodiment, the creping adhesive film has a composition that
is the same or similar to a creping adhesive film disposed on a
Yankee dryer. Next, one or more frequencies can be applied to the
sensor substrate and the oscillation frequency of the sensor
substrate can be measured using a QCM and/or QCMD technique. The
data acquired can be used to determine one or more characteristics
of the creping adhesive film. In an embodiment, one or more
frequencies can be applied using the QCM and/or QCMD techniques to
the sensor substrate under various conditions (e.g., modification
of the temperature, exposure to humidity (before and after),
exposure to water (before and after), and the like), where the
conditions can be designed to resemble the actual processing
conditions that the creping adhesion film is experiencing. Once the
data has been analyzed, the composition of the creping adhesive
film disposed on the Yankee dryer can be modified (e.g., as
described herein) based on the analysis of the characteristic(s) of
the creping adhesive film. This process can be repeated as needed
to obtain the desired creping adhesive film and resulting tissue or
towel product. As noted above, the analysis may include modifying
the composition of the creping adhesion film and testing it prior
to implementing the modified creping adhesion film in the
manufacturing process. Thus, an exemplary embodiment of the present
disclosure enables the creping adhesive film to be designed and
tested prior to implementation, which can be conducted in real time
or near real time.
EXAMPLES
[0052] Now having described the embodiments, in general, the
examples describe some additional embodiments. While embodiments
are described in connection with the examples and the corresponding
text and figures, there is no intent to limit embodiments of the
disclosure to these descriptions. On the contrary, the intent is to
cover all alternatives, modifications, and equivalents included
within the spirit and scope of exemplary embodiments.
Examples
Experimental Data
[0053] Creping Adhesives:
[0054] Commercial polyamidoamine-epichlorohydrin resins were used
in these studies, designated as Sample A, Sample B.
[0055] Conventional Tests:
[0056] Film insolubility and rewettability were measured in a
combined test. For each adhesive sample, an adhesive film of a
fixed thickness was prepared in a beaker by drying at 90.degree. C.
for 1 hr followed by 4 hr drying at 110.degree. C. The dry film was
weighed (initial dry film weight), covered with distilled water and
agitated in a shaker at room temperature. The undissolved solids
were separated, weighed (wet film weight after agitation in water),
dried and weighed again (dry film weight after solubilization). The
Percent Insolubility and Rewet Ratio were calculated as
follows:
Percent Insolubility=[(Dry film weight after
solubilization)/(Initial dry film weight)].times.100
Rewet Ratio=(Wet film weight after agitation in water)/(Dry film
weight after solubilization)
[0057] Film shear modulus was measured using an Anton Paar MCR 300
Rheometer. Adhesive films (1 mm thickness) were cast by drying at
90.degree. C. for 5-8 hrs. Small disks having 8-mm in diameter were
punched out of the adhesive films using a die. The disks were
re-dried at 90.degree. C. prior to testing. The geometry used for
the oscillation test was parallel plates. The shear storage and the
shear loss modulus were determined at 110.degree. C., 100 Hz and 1%
strain. The complex shear modulus referred to as "shear modulus"
was calculated from the shear storage and shear loss moduli.
[0058] QCMD Test:
[0059] A creping adhesive solution was spin coated on a gold coated
quartz crystal sensor. The adhesive coated sensors was dried and
cured in an oven at 110.degree. C. for 15 min. Depending on the
adhesive solution and its viscosity, the film thickness of dry
films ranged from about 20-150 nm.
[0060] A Q-Sense E4 system (Biolin Scientific AB, Vastra Frolunda,
Sweden) was used to make QCMD measurements for real-time studies of
mass or thickness changes and viscoelastic properties of creping
adhesive films exposed to moisture. Two QCMD modules were used. A
flow module was used for measuring the film insolubility and rewet
ratio parameters. In this module, water flows over the creping
adhesive film. A humidity module was used for measuring the rewet
ratio and shear modulus. In the humidity module, creping adhesive
films were exposed to a controlled level of humid air. Relative
humidity levels were generated by using various salt solutions that
pass through a cell separated by a gas permeable membrane. The
membrane prevented the coated sensor from contact with the liquid,
but allowed humid air to penetrate and create a controlled relative
humidity (RH) level over the sensor. In both modules the
temperature can be controlled from room temperature to 50.degree.
C. For this Example, all the QCMD measurements were carried out at
room temperature.
[0061] In the QCMD flow module test, the film thickness of the dry
adhesive film was first measured using QCMD. Then water was passed
through the chamber where an adhesive coated sensor was placed. The
oscillating frequency change was recorded until equilibrium
reached, which took approximately 1 hr. The modeling within the
Q-Sense software allowed calculation of the film thickness and
weight changes. After the QCMD run, the sensor with the remaining
coating film was re-dried and the film thickness was measured
again. Two typical curves shown in FIGS. 1A and 1B have been
constructed based on the QCMD results, one for a relatively
insoluble film such as Sample A and another for a soluble adhesive
film such as Sample B.
[0062] The % insolubility and rewet ratio were calculated as
follows:
% Insolubility = 2 0 .times. 100 ##EQU00001## Rewet Ratio = 1 2
##EQU00001.2##
[0063] In the humidity module test, a liquid with a salt solution
was passed through the cell to generate the predetermined relative
humidity level (e.g., RH1, RH2, RH3, etc.). A thickness change as
shown in FIG. 2 was calculated using the Q-sense modeling software.
A typical curve was observed for tested adhesive as the RH was
changing.
[0064] The rewet ratio was calculated as follows:
Rewet ratio 1 = 2 - 1 1 .times. 100 ##EQU00002##
for a change between RH1 to RH2
Rewet ratio 2 = 3 - 1 1 .times. 100 ##EQU00003##
for a change between RH1 to RH3.
[0065] The humidity module rewet ratio is different from the flow
module rewet ratio since one is measured in humid air and another
in water, but both can be useful indicators of the creping adhesive
performance
[0066] A shear modulus corresponding to each RH level was also
calculated using the Q-sense modeling software.
[0067] Peel Adhesion Test:
[0068] An adhesive film was cast on a hot metal plate using a
wire-wound rod. The film was cured for a set time before a wet
cotton strip was pressed into the film. After the strip and the
film were dried for a set time, the peel force was measured in a
180.degree. peel test under controlled temperature and peel speed.
Two temperature conditions were used to simulate extreme curing
conditions: (1) Low temperature (LT)--90.degree. C. for 30 sec and
(2) High temperature (HT)--110.degree. C. for 5 min.
[0069] Crepe Adhesive Characteristics Measurements:
[0070] Table 1 summarizes characteristics of two commercial
adhesives, Sample A and Sample B, and their blends measured using
both conventional and QCMD methods. The results in FIGS. 3A to 3C
show excellent linear correlations between % insolubility, rewet
ratio, and shear modulus, measured by conventional and QCMD
methods.
TABLE-US-00001 TABLE 1 Characteristics of creping adhesives
measured by conventional and QCMD techniques. QCMD methods Sample
A/ Shear Sample B Conventional methods Rewet Modulus blends % Shear
% ratio (Pa) (dry basis Insol- Rewet Modulus Insol- (flow (humidity
ratio) ubility ratio (kPa) ubility module) module) 100/0 69 16 365
51 5.2 3.3 75/25 62 22 43 8.1 50/50 54 30 230 33 10.4 1.2 25/75 45
53 21 22.3 0/100 0 n/a* 150 15 6.5 0.02 The data points for 100%
Sample B were not used in correlations for % insolubility and rewet
ratio because Sample B completely solubilizes in the conventional
test; whereas in the QCMD test soluble adhesive films can still be
fully characterized.
[0071] The data in Table 2 shows that the time required for QCMD
measurements was significantly shorter than for conventional
methods.
TABLE-US-00002 TABLE 2 Time required for measuring crepe adhesive
characteristics using conventional and QCMD methods. Test Time for
Test Time for Conventional QCM-D Measured methods methods
characteristics (hr) (hr) % Insolubility 10 5 Rewet ratio 10 5
Shear 10 3 modulus
[0072] Furthermore, QCMD data can be used to predict adhesion
performance of creping adhesives. Table 3 summarizes the data for
creping adhesive characteristics measured by QCMD method and
corresponding peel adhesion data at two test temperatures. The two
peel test temperatures exemplify extreme conditions on the Yankee
dryer, which would require different film adhesive characteristics
with regard to insolubility, rewet, and shear modulus.
TABLE-US-00003 TABLE 3 Film characteristics measured using QCMD and
corresponding peel adhesion. Peel Adhesion Sample A/ Peel Force
Peel Force Sample B QCMD methods at low at high blends % Shear
temperature temperature (dry basis Insolu- Rewet Modulus (LT) (HT)
ratio) bility ratio (Pa) (g-force) (g-force) 0 51 5.2 3.3 920 110
25 43 8.1 805 170 50 33 10.4 1.2 665 345 75 21 22.3 455 455 100
0.02 410 550
[0073] FIGS. 4A to 4F illustrate the correlation between peel force
and the characteristics measured by QCMD. The QCMD methods predict
that an adhesive producing a highly insoluble film with a low rewet
ratio and high shear modulus (hard film) should provide high
adhesion when the Yankee dryer temperature runs on a low side. This
is consistent with practical observations that require a harder and
less moisture sensitive coating to perform well under low
temperature creping operations. In contrast, for the high
temperature Yankee dryer, the QCMD method predicts that a more
soluble, highly rewettable and soft film (low shear modulus) is
preferred to provide high adhesion. Again, this is consistent with
a desire for soft and rewetable coating for high temperature
creping operations.
[0074] It should be noted that ratios, concentrations, amounts, and
other numerical data may be expressed herein in a range format. It
is to be understood that such a range format is used for
convenience and brevity, and thus, should be interpreted in a
flexible manner to include not only the numerical values explicitly
recited as the limits of the range, but also to include all the
individual numerical values or sub-ranges encompassed within that
range as if each numerical value and sub-range is explicitly
recited. To illustrate, a concentration range of "about 0.1% to
about 5%" should be interpreted to include not only the explicitly
recited concentration of about 0.1 wt % to about 5 wt %, but also
include individual concentrations (e.g., 1%, 2%, 3%, and 4%) and
the sub-ranges (e.g., 0.5%, 1.1%, 2.2%, 3.3%, and 4.4%) within the
indicated range. In an embodiment, the term "about" can include
traditional rounding according to the numerical value and what is
being measured. In addition, the phrase "about `x` to `y`" includes
"about `x` to about `y`".
[0075] It should be emphasized that the above-described embodiments
of the present disclosure are merely possible examples of
implementations, and are merely set forth for a clear understanding
of the principles of this disclosure. Many variations and
modifications may be made to the above-described embodiment(s) of
the disclosure without departing substantially from the spirit and
principles of the disclosure. All such modifications and variations
are intended to be included herein within the scope of this
disclosure and protected by the following claims.
* * * * *