Note: Descriptions are shown in the official language in which they were submitted.
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METHOD FOR USING HYDROPHOBICALLY ASSOCIATIVE
POLYMERS IN PREPARING CELLULOSIC FIBER COMPOSITIONS,
AND CELLULOSIC FIBER COMPOSITIONS INCORPORATING
THE HYDROPHOBICALLY ASSOCIATIVE POLYMERS
BACKGROUND OF THE INVENTION
CROSS REFERENCE TO RELATED APPLICATIONS
1. Field of the Invention
The present invention relates to using hydrophobically modified water-soluble
polymers, also referred to hereinafter as hydrophobically associative polymers
or HAPs,
in the preparation of cellulosic fiber compositions. The present invention
further relates
to cellulosic fiber compositions, such as paper and paperboard, which
incorporate the
HAPs
2. Description of Background and Other Information
The making of cellulosic fiber sheets - particularly paper and paperboard -
includes the following:
- producing an aqueous slurry of cellulosic fiber, which may also contain
inorganic mineral extenders or pigments;
- depositing this slurry on a moving papermaking wire or fabric; and
- forming a sheet from the solid components of the slurry by draining the
water.
The foregoing is followed by pressing and drying the sheet to further remove
water. Organic and inorganic chemicals are often added to the slurry prior to
the sheet
forming step to make the papermaking method less costly or more rapid, or to
attain
specific properties in the final paper product.
The paper industry continuously strives to improve paper quality, increase
productivity, and reduce manufacturing costs. Chemicals are often added to the
fibrous
slurry before it reaches the papermaking wire or fabric, to improve the method
drainage/dewatering and solids retention; these chemicals are called drainage
and/or
retention aids.
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As to drainage/dewatering improvement, drainage or dewatering of the fibrous
slurry on the papermaking wire or fabric is often the limiting step in
achieving faster
method speeds. Improved dewatering can also result in a dryer sheet in the
press and
dryer sections, resulting in reduced steam consumption. Yet further, this is
the stage in
the papermaking method that determines many sheet final properties.
With respect to solids retention, papermaking retention aids are used to
increase
the retention of fine furnish solids in the web during the turbulent method of
draining and
forming the paper web. Without adequate retention of the fine solids, they are
either lost
to the method effluent or accumulate to high levels in the recirculating white
water loop,
potentially causing deposit buildup and impairing paper machine drainage.
Additionally,
insufficient retention of the fine solids increases the papermakers' cost due
to loss of
additives intended to be adsorbed on the fiber to provide the respective paper
opacity,
strength, or sizing property.
High MW water-soluble polymers with either cationic or anionic charge have
traditionally been used as retention and drainage aids. Recent development of
inorganic
microparticles, known as retention and drainage aids, in combination with high
MW
water-soluble polymers, have shown superior retention and drainge efficacy
compared
to conventional high MW water-soluble polymers. U.S. Patent Nos. 4,294,885 and
4,388,150 teach the use of starch polymers with colloidal silica. U.S. Patent
No.
4,753,710 teaches flocculating the pulp furnish with a high MW cationic
flocculant,
inducing shear to the flocculated furnish, and then introducing bentonite clay
to the
furnish. U.S. Patent Nos. 5,274,055 and 5,167,766 disclose using chemically
crosslinked
organic microparticle or micropolymers as retention and drainage aids in
papermaking
process.
Hydropohobically modified water-soluble polymers, also referred to hereinafter
as hydrophobically associative polymers or HAPs, are known to those skilled in
the art,
for example see the Encyclopedia of Polymer Science and Engineering,
2°d edition, 17,
772-779. U.S. Patents Nos. 4,432,881 and 4,861,499 disclose the use of these
polymers
as thickening agents for paint formulations and for applications in oil
recovery methods,
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such as drilling mud formulations, fracturing fluids, liquid mobility control
agents,
friction reducing agents, hydraulic fluids, and lubricants. These patents do
not teach or
suggest the use of the polymers in cellulosic compositions such as paper, or
in methods
for preparing these cellulosic compositions.
U.S. Patent No. 4,305,860 discloses the preparation of stable, pumpable,
solvent-
free polyampholyte lattices (colloidal dispersions of a solid copolymer in
water)
characterized by their colloidal nature and their high solids content and low
bulk
viscosity. The lattices are prepared by polymerizing about 10 to 30 mole % of
at least
one cationic monomer, 5 to 30 mole % of at least one anionic monomer, 15 to 35
mole
% of at least one hydrophobic monomer and S to 70 mole % of at least one non-
ionic
hydrophilic monomer, with the monomer percentages totaling 100 mole %, in the
presence of water and a free-radical initiator and optionally a chelating
agent. The
lattices are taught to be particularly useful as pigment retention and
drainage aids in the
manufacture of paper and may be added to the pulp while the latter is in the
headbox,
beater, hydropulper or stock chest. The high hydrophobic group content (>15
mole %)
makes this disclosed polymer insoluble in aqueous solution, which
distinguishes itself
from the HAP polymers disclosed in the present invention.
EP 0 896 966 A1 discloses the preparation of associative polymers by inverse
emulsion procedures utilizing a pendant acrylate hydrophobe chain extended
with a
polyoxyethylene group. The associative acrylic polymers comprise from 95 to
99.95%
moles of at least one monomer selected from neutral ethylene, anionic or
cationic
monomers, from 0.05 to 5% moles of at least one acrylic monomer containing the
radical
2,4,6-triphenoethyl benzene, and from 0 to 0.2% moles of at least one
polyunsaturated
monomer. It is preferred that the associative polymers contain from 0.5 to 5
molar % of
polyoxyethylene 2,4,6-triphenoethyl benzene methacrylate. The polymers may be
used
in diverse areas, such as paints, glues and adhesives, construction, textiles
and paper. The
composition is claimed for use as a thickener, flocculation agent, and/or
charge retention
agent; no data or further specification is provided for the utilization.
SUMMARY OF THE INVENTION
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The present invention is directed to a cellulosic fiber composition,
particularly a
cellulosic sheet such as paper or paperboard. The invention is also directed
to a method
for making the composition.
The present invention relates to a method of making a cellulosic fiber
composition that includes adding, to a cellulosic pulp slurry, a HAP and
relates to a
cellulosic fiber composition including an aqueous slurry of cellulosic pulp
and a HAP.
The HAP is preferably a copolymer including hydrophobic groups that are
capable of
forming a physical network structure through hydrophobic association, and has
at least
one monomer selected from the group consisting of nonionic ethylenically
unsaturated
monomers, cationic ethylenically unsaturated monomers, or anionic
ethylenically
unsaturated monomers.
The HAP is highly associative and forms a network structure in aqueous
solution
as demonstrated by a tan b value less than an analogous polymer without the
hydrophobic
modification, as determined by viscoelastic characterizations of a
0.5°./° solution. A
significent improvement in retention and drainage activity is obtained when
HAP is
applied to a pulp furnish, and at the same time a satisfactory sheet formation
is
maintained, which is the unique property that a traditional flocculant could
not achieve.
The HAP is usually water soluble.
The HAP may include at least one hydrophobic ethylenically unsaturated
monomer present in an amount from about 0.001 mole percent to about 10 mole
percent,
and at least one monomer selected from a nonionic ethylenically unsaturated
monomer,
a cationic ethylenically unsaturated monomer, or an anionic ethylenically
unsaturated
monomer with the proviso that the at least one hydrophobic ethylenically
unsaturated
monomer does not contain 2,4,6-triphenoethyl benzene.
The at least one hydrophobic ethylenically unsaturated monomer may be an
ethylenically unsaturated monomer having at least one pendant hydrophobic
group of the
general structure:
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R,
CH, = C - R~ - R3 - R~ - RS Z- Figure 1
wherein R, is hydrogen or methyl; R,, when present, is -CH,-, -C(O)-O-, -O-
C(O)-, -
C(O)-NR6-, -NR6-C(O)-,or -O-; R3, when present, is -(-CH,-CHR,-O-)n , C,-C~o
alkyl, or
C,-C,o hydroxy alkyl wherein n equals 1 to 40 and R, is as decribed above; R~,
when
present, is -NR6- or -N+(R6)Z-; RS is the pendant hydrophobic group selected
from one or
more of C~-C,o alkyls, C4-C,o cycloalkyls, polynuclear aromatic hydrocarbon
groups,
alkaryls wherein alkyl has one or more carbons, or haloalkyls of four or more
carbons;
R6, when present, is hydrogen, methyl, CH,=CR,-CH,-, equivalent to the pendent
hydrophobic group RS as described above, or a mixture thereof; and Z, present
when R4
is -N~(R6)z-, is the conjugated base of an acid; with the proviso that RS is
not 2,4,6-
triphenoethyl benzene.
The polynuclear aromatic hydrocarbon group may be naphthyl. The haloalkyls
of four or more carbons may be perfluoroalkyls which preferably are selected
from one
or more of C4F9-C~oF'4,. The pendant hydrophobic group may be polyalkyleneoxy
groups
wherein the alkylene is propylene or higher alkylene and there is at least one
alkyleneoxy
unit per hydrophobic moiety or may be selected from one or more of C4-Czo
alkyl groups
or preferably from one or more of C8-Czo alkyl groups.
Preferably the hydrophobic ethylenically unsaturated monomer depicted in
Figure
1 may be selected from one or more hydrocarbon esters of ethylenically
unsaturated
carboxylic acids and their salts, N-alkyl ethylenically unsaturated amides, a-
olefins, vinyl
esters, vinyl ethers, N-vinyl amides, alkylstyrenes, alkyl polyethyleneglycol
(meth)acrylates, or N-alkyl ethylenically unsaturated cationic monomers. The
ethylenically unsaturated carboxylic acids may preferably be selected from the
C,o-C,o
alkyl esters of acrylic and methacrylic acid and more preferably from dodecyl
acrylate
or dodecyl methacrylate. The ethylenically unsaturated amides may preferably
be
selected from N-octadecyl acrylamide, N-octadecyl methacrylamide, or N,N-
dioctyl
acrylamide. The a-olefins may preferably be selected from 1-octene, 1-decene,
1-
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dodecene, or 1-hexadecene. The vinyl esters may preferably be vinyl laurate or
vinyl
stearate. The vinyl alkyl ethers may preferably be dodecyl vinyl ether or
hexadecyl vinyl
ether. The N-vinyl amides may preferably be N-vinyl lauramide or N-vinyl
stearamide.
The alkylstyrene may preferably be t-butyl styrene. The alkyl
polyethyleneglycol
(meth)acrylates may preferably be selected from laurylpolyethoxy(23)
methacrylate. The
N-alkyl ethylenically unsaturated cationic monomers may preferably be selected
from the
C,o-Coo alkyl halide quaternary salts of methyldiallyamine, N,N-
dimethylaminoalkyl(meth)acrylates, and N,N-dialkylaminoalkyl(meth)acrylamides.
The at least one nonionic ethylenically unsaturated monomer may be one or more
of acrylamide, methacrylamide, N-alkylacrylamides, N,N-dialkylacrylamides,
methyl
acrylate, methyl methacrylate, acrylonitrile, N-vinyl methylacetamide, N-
vinyl methyl
formamide, vinyl acetate, or N-vinyl pyrrolidone. The N-alkylacrylamide is
preferably
N-methylacrylamide and the N,N-dialkylacrylamide is preferably N,N-
dimethylacrylamide. The at least one nonionic ethylenically unsaturated
monomer is
1 S preferably one or more of acrylamide, methacrylamide, or N-
methylacrylamide and more
preferably acrylamide.
The at least one anionic ethylenically unsaturated monomer may be one or more
of acrylic acid, methacrylic acid, 2-acrylamido-2-methyl-propane sulfonate,
sulfoethyl-
(meth)acrylate, vinylsulfonic acid, styrene sulfonic acid, malefic acid or the
salts thereof,
preferably one or more of acrylic acid, methacrylic acid or the salts thereof
and more
preferably one or more of the sodium or ammonium salts of acrylic acid.
The at least one cationic ethylenically unsaturated monomer may be selected
from
one or more of diallylamine, the (meth)acrylates of dialkylaminoalkyl
compounds, the
(meth)acrylamides of dialkylaminoalkyl compounds, the N-vinylamine hydrolyzate
of
N-vinylformamide, and the salts and quaternaries thereof. The quaternary salt
of
diallylamine may preferably be diallyldimethylammonium chloride. The
dialkylaminoalkyl (meth)acrylamide may preferably be N,N-
dimethylaminopropylacrylamide, the acid or quantenary salt thereof may
preferably be
N,N,N-trimethylaminopropylacrylamide chloride. The dialkylaminoalkyl
(meth)acrylate
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may preferably be N,N-dimethylaminoethylacrylate, the acid or quantenary salt
thereof
may preferably be N,N,N-trimethylaminoethylacrylate chloride.The at least one
cationic
ethylenically unsaturated monomer may also be selected from one or more of the
compounds of the following general formulae:
R, O R,
CH,=C-C-X-A-N+-R, Z- Figure2
R4
wherein
R, is hydrogen or methyl,
R" R" and R4 are hydrogen, alkyl of C, to C, , or hydroxyethyl, .
R, and R3 or R, and R4 can combined to form a cyclic ring containing one of
more hetero
atoms, Z is the conjugate base of an acid,
X is oxygen or NR, wherein R, is as defined above, and
A is an alkylene group of C, to C,2; or
CH, CH,
RS-C C-R5
HzC CHz
\ /
N+ Z-
/ \
R, R8 Figure 3
wherein RS and R6 are hydrogen or methyl,
R, and R8 are hydrogen, alkyl of C, to C3, or hydroxyethyl; and
Z is as defined above;
or N-vinylformamides and the associated hydrolyzates as represented by
recurring units
of
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CH,_=CH
N Figure 4
/\
R, CO-R,
or
CH,=CH
N Figure 5
/ \
R, R
or
CHZ=CH
N+-R3 Z- Figure 6
/\
R, Rz
wherein R" R, and R, are each H or C, to C, alkyl, and
Z is defined as above.
It is noted that the description of the hydrophobic ethylenically unsaturated
monomer encompasses the cationic ethylenically unsaturated monomers depicted
in
Figues 2-6 wherein, for example, the definition of R, of Figures 2, 4-S and R,
of Figure
3 are substituted with pendant hydrophobic moeity RS of Figure 1.
It is preferable that HAP in accordance with this invention (an 0.5% aqueous
solution of the HAP) have a dynamic oscillation frequency sweep tan delta
value at
0.0068 Hz less than an analogous polymer absent the hydrophobic ethylenically
unsaturated monomer, most preferably less than 1. It is also preferable that
the at least
one hydrophobic ethylenically unsaturated monomer groups be present in an
amount
from about 0.01 mole percent to about 10 mole percent, and more preferably in
an
amount from about 0.1 mole percent to about 5.0 mole percent.
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The HAP used in this invention may be an anionic, nonionic, cationic or
amphoteric copolymer, and preferably an anionic copolymer. The anionic
copolymer
may include at least one hydrophobic ethylenically unsaturated monomer and at
least one
anionic ethylenically unsaturated monomer and may further include at least one
nonionic
ethylenically unsaturated monomer.
The anionic copolymer may include about 0.001 mole percent to about 10 mole
percent of the at least one hydrophobic ethylenically unsaturated monomer,
about 1 mole
percent to about 99.999 mole percent of the at least one anionic ethylenically
unsaturated
monomer, and about 1 mole percent to about 99.999 mole percent of the at least
one
nonionic ethylenically unsaturated monomer; preferably about 0.01 mole percent
to about
5 mole percent of the at least one hydrophobic ethylenically unsaturated
monomer, about
10 mole percent to about 90 mole percent of the at least one anionic
ethylerrically
unsaturated monomer, and about 10 mole percent to about 90 mole percent of the
at least
one nonionic ethylenically unsaturated monomer; and more preferably about 0.1
mole
percent to about 2.0 mole percent of the at least one hydrophobic
ethylenically
unsaturated monomer, about 30 mole percent to about 70 mole percent of the at
least one
anionic ethylenically unsaturated monomer, and about 50 mole percent to about
70 mole
percent of the at least one nonionic ethylenically unsaturated monomer.
The inventive cellulosic pulp slurry containing the HAP may also include, at
the
option of the skilled worker, other components such as at least one
flocculant, at least one
starch, at least one inorganic or organic coagulant, or at least one filler.
The present invention also includes a cellulosic sheet produced by the
inventive
method. The cellulosic sheet may include paper and paperboard incorporating
the HAP.
The present invention also relates to a method of making a cellulosic fiber
composition which includes adding, to a cellulosic pulp slurry, a HAP and
relates to a
cellulosic fiber composition including an aqueous slurry of cellulosic pulp
and a HAP,
where the HAP includes at least one hydrophobic ethylenically unsaturated
monomer
present in an amount from about 0.001 mole percent to about 10 mole percent
and
selected from one or more of C,o C,o alkyl esters of acrylic and methacrylic
acid; and at
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least one monomer selected from: a) about 1 mole percent to about 99.999 mole
percent
of at least one nonionic ethylenically unsaturated monomer selected from one
or more
of acrylamide, methacrylamide, N-alkylacrylamides, N,N-dialkylacrylamides,
methyl
acrylate, methyl methacrylate, acrylonitrile, N-vinyl methylacetamide, N-vinyl
methyl
formamide, vinyl acetate, or N-vinyl pyrrolidone; b) about 1 mole percent to
about
99.999 mole percent of at least one anionic ethylenically unsaturated monomer
selected
from one or more of acrylic acid, methylacrylic acid, 2-acrylamido-2-methyl-
propane
sulfonate, sulfoethyl-(meth)acrylate, vinylsulfonic acid, styrene sulfonic
acid, malefic acid
or the salts thereof; or c) about 1 mole percent to about 99.999 mole percent
of at least
one cationic ethylenically unsaturated monomer selected from one or more of
diallylamine, the (meth)acrylates of dialkylaminoalkyl compounds, the
(meth)acrylamides of dialkylaminoalkyl compounds, the N-vinylamine hydrolyzate
'of
N-vinylformamide, and the salts and quaternaries thereof.
The HAP may preferably include at least one hydrophobic ethylenically
unsaturated monomer present in an amount from about 0.001 mole percent to
about 10
mole percent and selected from one or more of C,o-CZO alkyl esters of acrylic
and
methacrylic acid; and at least one monomer selected from: a) about 1 mole
percent to
about 99.999 mole percent of at least one nonionic ethylenically unsaturated
monomer
selected from one or more of acrylamide, methacrylamide, or N-
alkylacrylamides; b)
about 1 mole percent to about 99.999 mole percent of at least one anionic
ethylenically
unsaturated monomer selected from one or more of acrylic acid, methacrylic
acid or the
salts thereof; or c) about 1 mole percent to about 99.999 mole percent of at
least one
cationic ethylenically unsaturated monomer selected from one or more of N,N-
dialkylaminoalkyl acrylates, N,N-dialkylaminoalkyl methacrylates, the acid or
quaternary
salts thereof. Preferably, the at least one hydrophobic ethylenically
unsaturated monomer
may be selected from one or more of dodecyl acrylate or dodecyl methacrylate,
the
nonionic ethylenically unsaturated monomer may be acrylamide, the at least one
anionic
ethylenically unsaturated monomer may be selected from one or more of the
sodium or
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ammonium salts of acrylic acid, and the cationic ethylenically unsaturated
monomer may
be the methyl chloride quaternary of N,N-dimethylaminoethylacrylate.
To the aforementioned pulp slurry containing the HAP may be added, at the
option of the skilled worker, additional components, such as at least one
flocculant, at
least one starch, at least one coagulant, or at least one filler.
The present invention also relates to a method of making a cellulosic fiber
composition which includes adding, to a cellulosic pulp slurry, an anionic HAP
and
relates to a cellulosic fiber composition including an aqueous slurry of
cellulosic pulp and
an anionic HAP, where the anionic HAP preferably includes at least one
hydrophobic
ethylenically unsaturated monomer selected from one or more of lauryl acrylate
or lauryl
methacrylate, the at least one nonionic ethylenically unsaturated monomer
being
acrylamide, and the at least one anionic ethylenically unsaturated monomer
being acrylic
acid. To the aforementioned pulp slurry containing the HAP may be added, at
the option
of the skilled worker, additional components, such as at least one flocculant,
at least one
starch, at least one inorganic or organic coagulant, or at least one filler.
The invention
also relates to a cellulosic sheet produced by the aforesaid method and from
the aforesaid
composition. The cellulosic sheet may include paper and paperboard
incorporating the
HAP.
The cellulosic fiber composition of the invention preferably comprises the HAP
and its viscoelasticity properties, as discussed. Preferred cellulosic fiber
compositions
of the invention include paper.
DESCRIPTION OF THE INVENTION
1. Definitions
As used herein, the term "HAP" refers to the hydrophobically associative
polymer
of this invention.
As used herein, the term "hydrocarbon" includes "aliphatic", "cycloaliphatic",
and
"aromatic". The terms "aliphatic" and "cycloaliphatic" - unless stated
otherwise - are
understood as including "alkyl", "alkenyl", "alkynyl", and "cycloalkyl". The
term
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"aromatic" - also unless stated otherwise - is understood as including "aryl",
"aralkyl",
and "alkaryl".
Hydrocarbon groups are understood as including both nonsubstituted
hydrocarbon groups and substituted hydrocarbon groups, with the latter
refernng to the
hydrocarbon portion bearing additional substituents besides the carbon and
hydrogen.
Correspondingly, aliphatic, cycloaliphatic, and aromatic groups are understood
as
including both nonsubstituted aliphatic, cycloaliphatic, and aromatic groups
and
substituted aliphatic, cycloaliphatic, and aromatic groups, with the latter
refernng to the
aliphatic, cycloaliphatic, and aromatic portion bearing additional
substituents besides the
carbon and hydrogen.
Also as discussed herein, copolymers are understood as including polymers
consisting of, or consisting substantially of or consisting essentially of,
two different --
monomeric units. Copolymers are further understood as including polymers
incorporating three or more different monomeric units, e.g., terpolymers, etc.
2. Method of the Invention
The invention comprises a method of making cellulosic fiber compositions -
particularly cellulosic fiber webs, mare particularly cellulosic fiber sheets,
and still more
particularly paper and paperboard. This method comprises the addition of at
least one
HAP to a suitable paper furnish - e.g., a cellulosic fiber pulp or stock,
particularly a
cellulosic wood fiber pulp or stock.
Preferably this polymer is added to a slurry comprising an aqueous suspension
of the furnish. Also as a matter of preference, a cellulosic web -
particularly a sheet, and
still more particularly paper or paperboard - is formed from the slurry.
The method of the invention can entail the steps of providing a paper furnish
comprised of cellulosic fibers with or without additional mineral fillers
suspended in
water, depositing the furnish on a papermaking wire or fabric, and forming a
sheet out
of the solid components by dewatering the slurry, with the at least one HAP
being added
at one or more points during this method. Preferably, this polymer is
introduced into the
fibrous slurry prior to the dewatering sequence.
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The HAP serves to provide an increase in retention of fine particles and/or an
increase in fibrous dewatering. This polymer is particularly effective in
providing for
retention both of filler - where it is employed - and of cellulosic fiber
fines, these fines
being generated from the fiber during the method of the invention. It is
postulated that
HAPs form physical network structure through the hydrophobic group in aqueous
solution as demonstrated by their viscoelasticity behavior. Since the three-
dimension
structure of the HAP is less absorbed on the particle surface, better bridging
is provided
between particles, which leads to better retention and drainage activity.
Viscoelastic behavior as discussed herein (Rheology: Principles, Measurements,
and Applications, C.W. Macosko, Wiley, New York, NY.) denotes a time dependent
response to a deformation, i.e., at short times the material is hard and
glassy, whereas at
longer times the material is rubbery or viscous. A common way to measure this
._
phenomenon is by stress relaxation, where an instantaneous strain is imposed
upon a
material, and the resultant stress decay over time is recorded. A purely
viscous material
would exhibit a stress of zero once the strain becomes constant, while an
elastic solid
would show no stress decay. A viscoelastic material would exhibit a stress
decay
between these two extremes; thus exhibiting combined elastic and viscous
response, or
viscoelasticity.
Dynamic oscillation characterizations are conducted on the HAP materials to
characterize the viscoelastic properties, wherein a sample is deformed
sinusoidally. The
test is conducted via a stress sweep, wherein a constant frequency is applied
with an
increasing stress (amplitude), or conversely a frequency sweep, wherein a
constant stress
is applied with varied frequency. The measured strain of the elastic component
of the
material will be in phase with the imposed stress, whereas the viscous
component of the
material will be 90~ out of phase. The tan b is the ratio of the viscous to
elastic
components of the material, and characterizes the material as exhibiting more
viscous or
elastic properties. Thus, a material having a tan 8 of greater than 1 at a
specific frequency
would exhibit predominantly viscous behavior, and a tan 8 less than 1 would
exhibit
predominantly elastic behavior.
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The HAP may be utilized as the sole retention/drainage aid. Alternatively,
this
polymer may be employed in combination with at least one flocculant, such as a
conventional papermaking flocculant - e.g., a high MW cationic, anionic, or
nonionic
flocculant.
The method of the invention can be practiced using a papermaking apparatus or
system as discussed herein. It is emphasized that the inventive method is not
limited to
this particular apparatus or system, which is only provided as a
representative example
of what can be employed.
As reviewed in Handbook for Pulp and Paper Technologists (G.A. Smook,
TAPPI Press, Atlanta, GA), pulp components are usually metered into the
machine stock
chest at a consistency level between 2.8 and 3.2 wt %. The machine stock chest
will
usually contain the final mixture, although in some instances, small
concentrations ef
additives may be added just prior to the headbox. The machine chest stock is
usually
circulated to a constant head tank (stuff box), which feeds the stock through
a control
valve (the basis weight valve) into the paper machine approach system.
The heart of the approach system is the fan pump which serves to mix the stock
with the white water and deliver the blend to the headbox. Here the stock is
combined
with the circulating white water from the wire pit, and the consistency is
reduced to the
level required at the headbox (usually between about 0.5 wt % and about 1.0 wt
consistency).
The white water, which typically has a solids concentration of about 0.1
weight
percent or less, is liquid from the dewatering of the pulp slurry on the
papermaking wire
that drains into the wire pit.
After the fan pump, the pulp slurry typically passes through a centrifizgal
cleaner,
and then through a pressure screen, to a head box.
The centrifugal cleaner removes debris such as shives and slivers, and the
pressure screen removes gross contamination and deflocs the fibers. The
headbox serves
to distribute the stock onto the earlier indicated endless moving papermaking
wire or
fabric; this may be a Fourdrinier wire or a twin wire former.
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On the moving papermaking wire or fabric the slurry is dewatered; the
resulting
liquid is the white water as discussed above, draining from the slurry into
the wire pit.
This drainage forms the slurry into a sheet as it is carned on the wire or
fabric to the
press section.
Traveling through the press section, the sheet is pressed between rollers and
thereby subjected to further dewatering. The sheet continues through the press
section
into a dryer section, wherein it is additionally dried. From the dryer section
the sheet
continues through a calender stack. In the calender stack it is pressed
between metal
rollers to reduce thickness and smooth the surface.
From this calender stack the sheet is wound onto a reel.
The resultant paper may also be surface coated with a sizing agent or coating
material.
The materials utilized in the method of the invention include cellulosic pulp
and
at least one HAP. There can also be employed one or more additional materials,
including at least one starch, at least one filler, at least one inorganic or
organic
coagulant, and at least one conventional flocculant.
Where a flocculant is employed, the flocculant and the HAP may be added
simultaneously, or at different points in the method without an intermittent
shear point,
or at different points with an intermittent shear point between their
respective additions.
Preferably, the flocculant and the HAP are introduced into the method of the
invention
sequentially, i.e., at different points or times. The flocculant may be added
before or after
the HAP.
A shear may be affected to the stock between the addition of the flocculant
and
HAP when added sequentially. In an apparatus or system as discussed herein,
high shear
is effected at the fan pump, centrifugal cleaner, and pressure.
Consistent with the foregoing, the apparatus or system preferably is provided
with
suitable feed points for adding the previously discussed materials, such as
the flocculant
and the HAP. In this regard, the flocculant and / or the HAP may be added at a
feed point
before the fan pump (e.g., between the basis weight valve and the fan pump),
and / or at
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a feed point before the centrifugal cleaner (e.g., between the fan pump and
the centrifugal
cleaner), and/or at a feed point before the pressure screen (e.g., between the
centrifugal
cleaner and the pressure screen).
With respect to feed points for the other materials, starch, filler, or
coagulant may
be added at numerous points within the process as is known to those skilled in
the art.
The order in which the different materials are introduced into the method of
the
invention is not limited to that set forth in the preceding discussion, but
will generally be
based on practicality and performance for each specific application.
3. Materials Employed
a. Cellulosic Pulp
Suitable cellulosic fiber pulps for the method of the invention include
conventional papermaking stock such as traditional chemical pulp. For
instance,
bleached and unbleached sulfate pulp and sulfite pulp, mechanical pulp such as
groundwood, thermomechanical pulp, chemi-thermomechanical pulp, recycled pulp
such
1 S as old corrugated containers, newsprint, office waste, magazine paper and
other non-
deinked waste, deinked waste, and mixtures thereof, may be used.
b. Starch
Starch adds strength properties, particularly dry strength, to the cellulosic
product
obtained from the method of the invention . Particularly, starch increases
interfiber
bonding in the stock. Starch will also affect drainage properties.
Starches that may be used in the method of the invention include cationic and
amphoteric starches. Suitable starches include those derived from corn,
potato, wheat,
rice, tapioca, and the like.
Cationicity is imparted by the introduction of cationic groups, and
amphotericity
by the further introduction of anionic groups. For instance, cationic starches
may be
obtained by reacting starch with tertiary amines or with quaternary ammonium
compounds, e.g., dimethylaminoethanol and 3-chloro-2-
hydroxypropyltrimethylammonium chloride. Cationic starches preferably have a
cationic
degree of substitution (D.S.) - i.e., the average number of cationic groups
substituted for
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hydroxyl groups per anhydroglucose unit - of from about 0.01 to about 1.0,
more
preferably about 0.01 to about 0.10, more preferably about 0.02 to 0.04.
Amphoteric starches can be provided by the introduction of various different
anionic groups. Preferred amphoteric starches are those with a net
cationicity.
As an example, anionic phosphate groups can be introduced into cationic
starches
through reaction with phosphate salts or phosphate etherifying reagents. Where
the
cationic starch starting material is starch diethylaminoethyl ether, the
amount of
phosphate reagent employed in the modification preferably is that which will
provide
about 0.07- 0.18 mole of anionic groups per mole of cationic groups.
Other amphoteric starches that may be used are those made by introduction of
sulfosuccinate groups into cationic starches. This modification is
accomplished by
adding malefic acid half ester groups to a cationic starch and reacting the
maleate double
bond with sodium bisulfate.
As yet additional examples, cationic starch can be etherified with 3-chloro-2-
sulfopropionic acid, carboxyl groups can be introduced into starches by
reaction with
sodium chloroacetate or by hypochlorite oxidation, and propane sultone can be
employed
to treat cationic starches to provide amphotericity.
Further useful amphoteric starches can be obtained by xanthation of
diethylaminoethyl- and 2-(hydroxypropyl)trimethylammonium starch ethers.
Yet additionally, the modification can be extended by the introduction of
nonionic or hydroxyalkyl groups from treatment with ethylene oxide or
propylene oxide.
Starch is preferably employed, in the method of the invention, in a proportion
of
from about 1 1b. per ton to about 100 lbs. per ton of cellulosic pulp, based
on the dry
weight of the pulp. The starch concentration is more preferably from about 2.5
lbs. per
ton to about 50 lbs. per ton, and still more preferably from about 5 lbs. per
ton to about
25 lbs. per ton, of the pulp.
c. Filler
Filler provides optical properties to the cellulosic product. It provides
opacity
and brightness to the finished sheet, and improves its printing properties.
Fillers which
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are suitable include calcium carbonate (both naturally occurnng ground
carbonate and
synthetically produced precipitated carbonate), titanium oxide, talc, clay,
and gypsum.
The amount of filler employed can be that which results in a cellulosic
product of up to
about 50 weight percent filler, based on the dry weight of the pulp.
S d. Coa ug lant
The coagulant is utilized in addition to the flocculant and HAP to enhance
retention and drainage. The employed coagulant may be either inorganic or
organic.
The most common inorganic coagulant is an alumina species. Suitable examples
include technical grade aluminum sulfate (alum), polyaluminum chloride,
polyhydroxy
aluminum chloride, polyhydroxy aluminum sulfate, sodium aluminate, and the
like.
The organic coagulant is typically a synthetic, polymeric material. Suitable
examples include polyamines, poly(amido amines), polyDADMAC,
polyethyleneimine,
hydrolyzates and quaternized hydrolyzates of N-vinyl formamide polymers and
copolymers, and the like.
The coagulant is preferably employed, in the method of the invention, in a
proportion of from about 0.01 1b. per ton to about 50 lbs. per ton of
cellulosic pulp, based
on the dry weight of the pulp. The coagulant concentration is more preferably
from
about 0.05 lbs. per ton to about 20 lbs. per ton, and still more preferably
from about 0.1
1b. per ton to about 10 lbs. per ton, of the pulp.
e. Flocculant
Ionic flocculants conventional in the papermaking art are suitable as
flocculants
for the method of the present invention. Cationic, anionic, nonionic, and
amphoteric
flocculants - particularly, cationic, anionic, nonionic, and amphoteric
polymers - can be
used.
Polymers suitable as flocculants in the method of the invention include
homopolymers of a nonionic ethylenically unsaturated monomer. Copolymers of
monomers comprising two or more nonionic ethylenically unsaturated monomers
can
also be used, as can copolymers of monomers comprising at least one nonionic
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ethylenically unsaturated monomer and at least one cationic ethylenically
unsaturated
monomer and/or at least one anionic ethylenically unsaturated monomer.
The nonionic, cationic, and anionic ethylenically unsaturated monomers which
may be employed are those discussed herein as being appropriate for the at
least one HAP
of the invention.
Suitable nonionic ethylenically unsaturated monomers include acrylamide;
methacrylamide; N-alkylacrylamides, such as N-methylacrylamide; N,N-
dialkylacrylamides, such as N,N-dimethylacrylamide; methyl acrylate; methyl
methacrylate; acrylonitrile; N-vinyl methylacetamide; N-vinyl methyl
formamide; vinyl
acetate; N-vinyl pyrrolidone; hydroxyalkyl(meth) acrylates such as
hydroxyethyl(meth)
acrylate or hydroxypropyl(meth) acrylate; mixtures of any of the foregoing and
the like.
Of the foregoing, acrylamide, methacrylamide, and the N-alkylacrylamides are
preferred,
with acrylamide being particularly preferred.
Among the cationic ethylenically unsaturated monomers which may be used are
diallylamine, the (meth)acrylates of dialkylaminoalkyl compounds, the
(meth)acrylamides of dialkylaminoalkyl compounds, the N-vinylamine hydrolyzate
of
N-vinylformamide, and the salts and quaternaries thereof. The N,N-
dialkylaminoalkyl
acrylates and methacrylates, and their acid and quaternary salts, are
preferred, with the
methyl chloride quaternary of N,N-dimethylaminoethylacrylate being
particularly
preferred.Further as to the cationic monomers, suitable examples include those
of the
following general formulae:
R, O Rz
CHz=C-C-X-A-N+-R3 Z-
R4
where R, is hydrogen or methyl, RZ is hydrogen or lower alkyl of C, to C4, R3
and/or R4 are hydrogen, alkyl of C, to C,2 , aryl, or hydroxyethyl, and R, and
R3 or R, and
R4 can combine to form a cyclic ring containing one of more hetero atoms, Z is
the
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WO 01/40578 PCT/US00/32820
conjugate base of an acid, X is oxygen or NR, wherein R, is as defined above,
and A is
an alkylene group of C, to C,,; or
CH, CH,
RS-C C-R6
H,C CH,
\ /
N+ Z-
/ \
R, R8
where RS and R6 are hydrogen or methyl, R, is hydrogen or alkyl of C, to C,"
and R8 is
hydrogen, alkyl of C, to C,2, benzyl, or hydroxyethyl; and Z is as defined
above; or N-
vinylformamides and the associated hydrolyzates as represented by recurnng
units of
CH,=CH
N
/\
R' C O-RZ
or
CH2=CH
N
/\
R' Rz
or
CH,=CH
N+_R, Z_
/ \
R' R'
where R', RZ and R3 are each H or C, to C3 alkyl, and Z is defined above.
Suitable anionic ethylenically unsaturated monomers include acrylic acid,
methylacrylic acid, and their salts; 2-acrylamido-2-methyl-propane sulfonate;
sulfoethyl-
(meth)acrylate; vinylsulfonic acid; styrene sulfonic acid; and malefic and
other dibasic
acids and their salts. Acrylic acid, methacrylic acid and their salts are
preferred, with the
sodium and ammonium salts of acrylic acid being particularly preferred.
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The monomers may be polymerized into polymer by a number of initiator
systems, including free radical (thermal and redox methods), cationic, and
anionic
synthesis methods. The flocculant polymer may be prepared by a number of
commercial
means, including bulk polymerization, solution polymerization, dispersion
polymerization, and emulsion/inverse emulsion polymerization. The resultant
polymer
may be provided to the end use in a number of physical forms, including
aqueous
solution, dry solid powder, dispersion, and emulsion form.
The flocculant may be non-ionic, cationic, anionic, or amphoteric. Non-ionic
polymer flocculants will contain one or more of the previously described non-
ionic
monomers.
Cationic polymer flocculants will contain one or more of the cationic monomers
described above. The level of total cationic monomer, based upon molar
concentrations,
will range from about 1 to about 99%, preferably from about 2 to about 50%,
and still
more preferably from about 5 to about 40 mole % cationic monomer, with the
remaining
monomer being one of the previously described non-ionic monomers.
Anionic polymer flocculants will contain one or more of the anionic monomers
described above. The level of total anionic monomer, based upon molar
concentrations,
will range from about 1 to about 99%, preferably from about 2 to about 50%,
and still
more preferably from about 5 to about 40 mole % cationic monomer, with the
remaining
monomer being one of the previously described non-ionic monomers.
Amphoteric polymer flocculants will contain a combination of one or more of
the
described cationic and anionic monomers. Any combination of cationic and
anionic
monomers) are preferred, provided at least one cationic and one anionic
monomer are
utilized. The polymer may contain an excess of cationic monomer, an excess of
anionic
monomer, or equivalent amounts of both cationic and anionic monomers. The
level of
total ionic monomer, being the combined amount of both cationic and anionic
monomers, based upon molar concentrations, will range from about 1 to about
99%,
preferably from about 2 to about 80%, and still more preferably from about 5
to about 40
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WO 01/40578 PCT/US00/32820
mole % cationic monomer, with the remaining monomer being one of the
previously
described non-ionic monomers.
The flocculant is preferably employed, in the method of the invention, in a
proportion of from about 0.01 1b. per ton to about 10 lbs. per ton of
cellulosic pulp, based
upon active polymer weight and on the dry weight of the pulp. The
concentration of
flocculant is more preferably from about 0.05 1b. per ton to about 5 lbs. per
ton, and still
more preferably from about 0.1 1b. per ton to about 1 1b. per ton, of the
pulp.
f. Hydrophobically Associative Polymer (HAP)
The invention comprises at least one HAP. Suitable HAPs of the invention
include copolymers comprising at least one hydrophobic ethylenically
unsaturated
monomer with the proviso that the at least one hydrophobic ethylenically
unsaturated
monomer does not contain 2,4,6-triphenoethyl benzene. These copolymers further
include at least one nonionic ethylenically unsaturated monomer, and/or at
least one
cationic ethylenically unsaturated monomer, and/or at least one anionic
ethylenically
unsaturated monomer.
The indicated hydrophobic ethylenically unsaturated monomers include water-
insoluble hydrophobic ethylenically unsaturated monomers. Further as to the
hydrophobic ethylenically unsaturated monomers, they include ethylenically
unsaturated
monomers, particularly water-insoluble monomers and monomeric surfactants,
having
hydrophobic groups. The hydrophobic groups include hydrophobic organic groups,
such
as those having hydrophobicity comparable to one of the following: aliphatic
hydrocarbon groups having at least four carbons such as CQ to C,o alkyls and
cycloalkyls;
polynuclear aromatic hydrocarbon groups such as benzyls, substituted benzyls
and
naphthyls with the proviso that the substituted benzyl group is not 2,4,6-
triphenoethyl
benzene; alkaryls wherein alkyl has one or more carbons; haloalkyls of four or
more
carbons, preferably perfluoroalkyls; polyalkyleneoxy groups wherein the
alkylene is
propylene or higher alkylene and there is at least one alkyleneoxy unit per
hydrophobic
moiety. The preferred hydrophobic groups include those having at least 4
carbons or
more per hydrocarbon group, such as the C4-Czo alkyl groups or those having at
least 4
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WO 01/40578 PCT/US00/32820
carbons or more per perfluorocarbon group, such as the C~F9-C,oF4,.
Particularly
preferred are the C8-C~o alkyl groups.
Suitable hydrocarbon group-containing ethylenically unsaturated monomers
include the esters or amides of the C4 and higher alkyl groups.
Particular suitable esters include dodecyl acrylate, dodecyl methacrylate,
tridecyl
acrylate, tridecyl methacrylate, tetradecyl acrylate, tetradecyl methacrylate,
octadecyl
acrylate, octadecyl methacrylate, nonyl-a-phenyl acrylate, nonyl-a-phenyl
methacrylate,
dodecyl-a-phenyl acrylate, and dodecyl-a-phenyl methacrylate.
The C,o-C,o alkyl esters of acrylic and methacrylic acid are preferred. Of
these,
dodecyl acrylate and methacrylate are particularly preferred.
Also the following hydrocarbon group-containing ethylenically unsaturated
monomers may be used:
- N-alkyl ethylenically unsaturated amides, such as N-octadecyl acrylamide, N-
octadecyl methacrylamide, N,N-dioctyl acrylamide and similar derivatives
thereof;
- a-olefins, such as 1-octene, 1-decene, 1-dodecene, and 1-hexadecene;
- vinyl esters wherein the ester has at least eight carbons, such as vinyl
laurate and
vinyl stearate;
- vinyl ethers, such as dodecyl vinyl ether and hexadecyl vinyl ether;
- N-vinyl amides, such as N-vinyl lauramide and N-vinyl stearamide;
-alkylstyrenes, such as t-butyl styrene;
-alkyl polyethyleneglycol (meth)acrylates such as laurylpolyethoxy(23)
methacrylate; and
- N-alkyl ethylenically unsaturated cationic monomers such as the C,o-C~o
alkyl
halide quaternary salts of methyldiallyamine, N,N-
dimethylaminoalkyl(meth)acrylates,
and N,N-dialkylaminoalkyl(meth)acrylamides.
Suitable nonionic ethylenically unsaturated monomers include acrylamide;
methacrylamide; N-alkylacrylamides, such as N-methylacrylamide; N,N-
dialkylacrylamides, such as N,N-dimethylacrylamide; methyl acrylate; methyl
methacrylate; acrylonitrile; N-vinyl methylacetamide; N-vinyl methyl
formamide; vinyl
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acetate; N-vinyl pyrrolidone; mixtures of any of the foregoing and the like.
Of the
foregoing, acrylamide, methacrylamide, and the N-alkylacrylamides are
preferred, with
acrylamide being particularly preferred.
Among the cationic ethylenically unsaturated monomers which may be used are
diallylamine, the (meth)acrylates of dialkylaminoalkyl compounds, the
(meth)acrylamides of dialkylaminoalkyl compounds, the N-vinylamine hydrolyzate
of
N-vinylformamide, and the salts and quaternaries thereof. The N,N-
dialkylaminoalkyl
acrylates and methacrylates, and their acid and quaternary salts, are
preferred, with the
methyl chloride quaternary of N,N-dimethylaminoethylacrylate being
particularly
preferred.
Further as to the cationic monomers, suitable examples include those of the
following general formulae:
R, O Rz
CHZ=C-C-X-A-N+-R3 Z-
R4
where R, is hydrogen or methyl; RZ, R3 and R4 are hydrogen, alkyl of C, to C3,
or
hydroxyethyl; and RZ and R3 or Rz and R4 can combined to form a cyclic ring
containing
one or more hetero atoms; Z is the conjugate base of an acid;, X is oxygen or
NR,
wherein R, is as defined above; and A is an alkylene group of C, to C,~; or
CHZ CHz
RS-C C-R6
HZC CHz
\ /
N+ Z
/\
R, Rg
where RS and R6 are hydrogen or methyl, R, and R8 are hydrogen, alkyl of C, to
C3, or
hydroxyethyl; and Z is as defined above; or N-vinylformamides and the
associated
hydrolyzates as represented by recurnng units of
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CH,=CH
N
/ \
R' CO-R'
or
CH,=CH
N
/ \
R' Rz
or
CHZ CH
N+-R3 Z-
/\
R' RZ
where R', RZ and R3 are each H or C, to C3 alkyl, and Z is defined above.
Suitable anionic ethylenically unsaturated monomers include acrylic acid,
methylacrylic acid, and their salts; 2-acrylamido-2-methyl-propane sulfonate;
sulfoethyl-
(meth)acrylate; vinylsulfonic acid; styrene sulfonic acid; and malefic and
other dibasic
acids and their salts. Acrylic acid, methacrylic acid and their salts are
preferred, with the
sodium and ammonium salts of acrylic acid being particularly preferred.
As a matter of preference, the proportion of hydrophobic ethylenically
unsaturated monomer in the HAP is within a range which renders the polymer
hydrophobically associative - i.e., the hydrophobic monomer concentration is
low enough
so that the polymer is still water soluble or dispersible, but sufficient to
provide the
associative property as discussed herein. In this regard, the at least one HAP
preferably
comprises about 0.001 mole percent to about 10 mole percent - more preferably
about
0.01 mole percent to about 5 mole percent, and still more preferably about 0.1
mole
percent to about 2.0 mole percent - of the at least one hydrophobic
ethylenically
unsaturated monomer.
The HAPs used in the invention include anionic, nonionic, and cationic and
amphoteric copolymers. Of these, the anionic copolymers are preferred.
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The anionic copolymers comprise at least one hydrophobic ethylenically
unsaturated monomer and at least one anionic ethylenically unsaturated
monomer.
Preferably, the anionic copolymers further comprise at least one nonionic
ethylenically
unsaturated monomer. Particularly preferred are the terpolymers consisting of,
or
consisting essentially of, or substantially of, at least one hydrophobic
ethylenically
unsaturated monomer, at least one anionic ethylenically unsaturated monomer,
and at
least one nonionic ethylenically unsaturated monomer.
For the anionic copolymers the preferred hydrophobic ethylenically unsaturated
monomers are the hydrocarbon esters of a,(3-ethylenically unsaturated
carboxylic acids
and their salts, with dodecyl acrylate and dodecyl methacrylate being
particularly
preferred. Preferred nonionic ethylenically unsaturated monomers are
acrylamide and
methacrylamide. Preferred anionic ethylenically unsaturated monomers are
acrylic acid
and methacrylic acid.
The anionic copolymers preferably comprise about 0.001 mole percent to about
10 mole percent hydrophobic ethylenically unsaturated monomer, about 1 mole
percent
to about 99.999 mole percent nonionic ethylenically unsaturated monomer, and
about
1 mole percent to about 99.999 mole percent of the at least one anionic
ethylenically
unsaturated monomer. More preferably, they comprise about 0.01 mole percent to
about
S mole percent of the at least one hydrophobic ethylenically unsaturated
monomer, about
10 mole percent to about 90 mole percent of the at least one nonionic
ethylenically
unsaturated monomer, and about 10 mole percent to about 90 mole percent of the
at least
one anionic ethylenically unsaturated monomer. Still more preferably, they
comprise
about 0.1 mole percent to about 2.0 mole percent of the at least one
hydrophobic
ethylenically unsaturated monomer, about 50 mole percent to about 70 mole
percent of
the at least one nonionic ethylenically unsaturated monomer, and about 30 mole
percent
to about 70 mole percent of the at least one anionic ethylenically unsaturated
monomer.
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The monomers may be polymerized into a HAP polymer by a number of initiator
systems, including free radical (thermal and redox methods), cationic, and
anionic
synthesis methods. The HAP may be prepared by a number of commercial means,
including bulk polymerization, solution polymerization, micellar solution
polymerization,
dispersion polymerization, and emulsion/inverse emulsion polymerization. The
resultant
polymer may be provided to the end use in a number of physical forms,
including
aqueous solution, dry solid powder, dispersion, and emulsion form.
The HAP is preferably employed, in the method of the invention, in a
proportion
of from about 0.01 1b. per ton to about 10 lbs. per ton of cellulosic pulp,
based on the dry
weight of the pulp. The concentration of HAP is more preferably from about
0.05 1b. per
ton to about 5 lbs. per ton, and still more preferably from about 0.1 1b. per
ton to about
1 1b. per ton, of the pulp.
g. Further Additives
The method of the invention may yet additionally include conventional
additives
employed in their usual amounts for their usual purposes. Suitable examples
include
sizing, promoters, strength agents, dye fixatives, polymeric coagulants, and
the like. The
produced paper may also be surface treated with a surface size or coating
material.
4. Composition of the Invention
A factor affecting the concentration of HAP in the cellulosic composition of
the
invention is the proportion of the polymer added during the preparation
method. The
cellulosic composition of the invention - which preferably is a cellulosic
sheet, and more
preferably is paperboard or paper - preferably comprises about 0.01 to about
10 lbs. per
ton - more preferably about 0.05 to about 5 lbs. per ton, and still more
preferably about
0.1 weight percent to about 1 lbs. per ton - of the HAP, based on the dry
weight of the
composition.
EXPERIMENTAL SECTION
The invention is illustrated by the following procedures and tests; these are
provided for the purpose of representation, and are not to be construed as
limiting the
scope of the invention. Unless stated otherwise, all percentages, parts, etc.
are by weight.
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1. Preparation of the Flocculant HAPs of the Invention and Controls
a.) Solution Polymerization
HAPs used in the invention, the anionic copolymers II, III, and V to VII are
prepared from acrylamide (AM), acrylic acid (AA), and lauryl acrylate (LA).
Control
polymers, the anionic copolymers I and IV, are prepared without the
hydrophobically
modified monomer lauryl acrylate - i.e., from acrylamide and acrylic acid
alone.
Polymers I-VII are all prepared by solution polymerization. The relative
proportions of monomers used in each instance are set forth below.
TABLE I
Solution Polymer Sample Description
Polymer Monomers Feed Ratio (mole)
I (control) AA/AM 45/55
II AA/AM/LA 45/54/1
III AA/AM/LA 45/54/1
IV (control) AA/AM 30/70
V AA/AM/LA 30/69.5/0.5
VI AA/AM/LA 30/69/1
VII AA/AM/LA 30/68/2
In the case of Polymers II and III, a solution of 2.75 parts of acrylamide,
0.17
parts (lmol% of the monomers) of lauryl acrylate, 2.25 parts of acrylic acid,
1 part of the
nonionic surfactant (Tergitol 15-S-9), and 100 parts of deionized water is
deoxygenated
under stirring at room temperature by sparging with nitrogen for 45 minutes.
0.5 part of
a 2 mg KBr03 solution is added and 10 parts of 0.03% of NaS205 is injected by
a syringe
pump over 60 minutes. The copolymer is obtained by the precipitation of the
polymerization solution in acetone and dried under vacuum at 50° C
overnight.
Polymers V, VI and VII are prepared in the same manner, except for the ratio
of
the monomers. For Polymer V, the monomer ratio is 3.4 parts of acrylamide, 0.1
part
(0.5 mol% of the monomers) of lauryl acrylate, and 1.5 parts of acrylic acid.
For
Polymer VI, the monomer ratio is 3.4 parts of acrylamide, 0.19 parts (1 mol%
of the
monomers) of lauryl acrylate, and 1.5 parts of acrylic acid. For Polymer VII,
the
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monomer ratio is 3.4 parts of acrylamide, 0.38 parts (2 mol% of the monomers)
of lauryl
acrylate, and 1.5 parts of acrylic acid.
Polymer I is prepared using the same method and proportions as with Polymers
II and III, except without the lauryl acrylate. Polymer IV is prepared in the
same manner
as Polymer I, except that for Polymer IV the monomer ratio is 3.5 parts of
acrylamide and
1.5 parts of acrylic acid.
For each of Polymers I, II, and III, the resulting dried product is
redissolved in
deionized water to produce a 0.5% polymer solution which is subjected to
viscosity
characterization.
b). Dispersion Polymerization
Hydrophobic associative polymers are prepared via dispersion polymerization.
TABLE 2
Brine Dispersion Sample Description
Polymer Monomer Feed Ratio
(mole$)
VIII(control) AA/AM 50/50
IX AA/AM/LMA 49.9/50/0.1
X AA/AM/LMA 49.8/50/0.2
XI AA/AM/LA 50/49.75/0.25
XII AA/AM/LA 50/49.5/0.5
LMA - Lauryl methacrylate
LA - Lauryl acrylate
2. Viscosity Characterization
a). Solution Polymerization
The viscosity of each 0.5% solution is measured by Brookfield viscometer at 12
rpm and room temperature. The results are set forth in Table 3 below. The
molecular
weights of the HAPs II and III, and of the non-associative Polymer I, are
assumed to be
similar, because of their being prepared under substantially identical
synthesis conditions.
The 20 fold increase in 0.5% solution viscosity of the HAPs II and III over
the Polymer
I control sample is a qualitative indication of the incorporation of the
hydrophobic
monomer in Polymers II and III. The extremely high 0.5% solution viscosity for
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Polymers II and III also indicates that the HAPs of the invention are strongly
associative
in aqueous solution.
TABLE 3
Viscosity Characterization
Samples Monomers 0.5% Solution Viscosity (cP)
I (control) AA/AM 600
II AA/AM/LA 14,000
III AA/AM/LA 12,000
Viscosity and rheological characterizations are further conducted on Samples
IV
through VII to demonstrate the associative properties of the modified samples
compared
to the unmodified control. The described studies are conducted at 0.5% aqueous
solution. As is exhibited previously in Table 3, Brookfield viscosity at 12
rpm~is
conducted on the samples, exhibiting a significant increase in apparent
viscosity with
increased levels of hydrophobe. The highest level of hydrophobe exhibits a 10
fold
increase in Brookfield Viscosity due to associative interactions. Additional
studies are
also conducted with a controlled stress rheometer equipped with a cone and
plate
geometry, with a 60 mm diameter cone and a fixed angle of 2 degrees. The
apparent
viscosity of the 0.5% solid content polymer samples is determined at a
constant shear rate
of 10 sec-', with similar results observed as with the Brookfield viscometer,
in that a 10
fold increase in viscosity is observed with the highest level of hydrophobe,
indicating
strong associative behavior. A stress sweep is conducted with the instrument
in dynamic
stress oscillation mode, at a constant 1 Hz frequency, and a stress range of
0.1 to 10.0 Pa
in 20 logarithmic steps. The G~ storage modulus is assigned as the equilibrium
value in
the linear viscoelastic region, and is defined as:
G~=(zo~Yo)cos8
where i° is the stress amplitude, yo is the maximum strain amplitude,
and b is the phase
angle shift between the stress and resultant strain. The G~ storage modulus is
also
referred to as the gel modulus, and is taken as an indication of the degree
and strength of
CA 02390353 2002-05-07
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the network structure, as determined by the inter- /intra- molecular
hydrophobic
associations. At equivalent applied stress, materials with a higher G' value
will strain or
deform less, thus exhibiting a stronger gel complex or network structure. The
data
demonstrates a linear relationship between hydrophobe concentration and G'
storage
modulus, with the modulus increasing with increased level of hydrophobe, and
the
highest G' storage modulus for the highest level of hydrophobic substitution.
The
unmodified Polymer IV exhibits a storage modulus of 2 Pa, while the modified
Polymer
VII containing 2 mole % lauryl acrylate exhibits a storage modulus of 25.6 Pa.
A frequency sweep in dynamic oscillation mode is subsequently conducted with
the instrument in dynamic oscillation mode, at a constant stress of 0.1 Pa in
the linear
viscoelastic regime, and a frequency range of 0.0068 Hz to 10 Hz with 3
readings per
frequency decade. The tan b is the ratio of the loss (viscous) modulus to
storage (elastic)
modulus, determined according to:
tan 8 = loss modulus / storage modulus = G" / G'
Materials that possess a higher tan 8 value exhibit more viscous properties,
while a lower
tan 8 will indicate more elastic properties. At a low frequency such as 0.0068
Hz, the rate
of stress on the sample will permit a linear polymer to relax, and exhibit a
viscous type
response, or a higher tan 8. Polymers comprised either of a chemical or
physical network
exhibit significant structure of the polymer chains. These network structured
materials
are mechanically stable and do not relax within the time frame or frequency of
the
experiment. These materials exhibit lower values of tan 8, and thus are more
elastic. As
shown in Table 4, a tan b at 0.0068 Hz of 20 is observed for the unmodified
control
polymer, while the highest level of hydrophobe provides a tan 8 of 0.224.
Lower levels
of tan b are observed with higher levels of hydrophobic substitution over a
wide range
of frequencies, up to 6.8 Hz. This clearly demonstrates the strong associative
behavior
of the HAP, and it is consistent with the viscosity data discussed above.
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TABLE 4
Controlled Stress Rheometer Dynamic Oscillation Studies
Brookfield, Shear rate = Stress Sweep Frequency
rpm 10 sec -1 Sweep
Polymer Monomer Feed Ratio 0.5% soln vis, 0.5% soln G' ' Storage tan a, .0068
(mole %) mPas vis, mPas Modulus, Pa Hz
IV(control) AA/AM 30/70 650 1070 2 19.9
V AA/AM/LA 30/69.5/0.5 1700 2350 2.3 I.1
VI AA/AM/LA 30/69/1 8500 16400 12 0.363
VII AA/AM/LA 30/68/2 7000 10500 25.6 0.224
b). Dispersion Polymerization
The dispersion polymers are characterized according to equivalent methods as
described in the solution polymerization polymers. The data presented in
Table~.5
demonstrates similar results as with the solution polymerization products. The
0.5%
solution apparent viscosity is observed to increase with the introduction of
the
hydrophobic monomer. A stress sweep study in dynamic oscillation mode
demonstrates
a G~ storage modulus increase with samples IX and XI compared to the
unmodified
control sample VIII. A frequency sweep study in dynamic oscillation mode
demonstrates
a low tan 8 for the hydrophobic associative polymer compared to the unmodified
control.
TABLE 5
Controlled
Stress
Rheometer
Dynamic
Oscillation
Studies
Shear Stress SweepFrequency
rate
=
10 sec Sweep
-1
Polymer Monomer Feed RatioCharge0.5% solnG' Storage tan
8,
.0068
(mole Densityvis, mPasModulus, Hz
%) Pa
meq/g
VIII (control)AM/AA 50/50 6.4 530 3.39 7.23
IX AM/AA/LMA 50/49.9/0.17.5 1230 10.9 0.92
X AM/AA/LMA 50/49.8/0.27.0 510 Non-linear , n/a
XI AA/AM/LA 50/49.75/0.257.6 1270 10.9 0.72
XII AA/AM/LA 50/49.5/0.57.3 410 Non-linear n/a
LA - Lauryl acrylate
LMA - Lauryl methacrylate
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The dilute solution viscosity properties of the Table 5 HAP samples were
determined in aqueous solutions at various concentrations of NaCI and compared
to
Polyflex CP.3, a commercial polyacrylamide drainage aid (Cytec Industries,
Inc., West
Patterson, NJ) and Polymer E, a commercial high MW anionic polyacrylamide
flocculant. The data are presented in Table 5.1. As discussed in Introduction
to Physical
Polymer Science by L. H. Sperling (Whey Interscience, 1992), the dilute
solution
properties provide a relative indication of polymer molecular weight. In this
experiment,
the solvent viscosity ~° is compared to the polymer solution viscosity
r1. The relative
viscosity is the unitless ratio of the two:
1 0 ~rel rl/T10
and the specific viscosity is relative viscosity minus one:
rlsp - ~rel - 1
The reduced specific viscosity, referred to hereafter as the RSV, is the
specific
viscosity divided by the polymer concentration (C) in gram per deciliter
units:
RSV = rlsp / C
The units for RSV are deciliter per gram (dL/g), and as such describe the
hydrodynamic volume (HDV) of a polymer in solution. Thus a higher RSV
indicates a
large HDV in solution, and a higher MW when comparing conventional polymers.
The
experiment is conducted in the dilute regime such that no polymer coil overlap
is
occurring. The RSV values can be determined by capillary or rotational
viscometer
methods by measuring the respective efflux time or apparent viscosity of both
the solvent
and the polymer solutions. The data described in Table 5.1 were determined
with a
Brookfield rotational viscometer equipped with an ultra-low (UL) adapter,
capable of
determining the viscosity of low viscosity solutions. The data demonstrate the
effect on
polyelectrolyte RSV with varying salt concentrations, as is well known to
those skilled
in the art. The inventive HAP products demonstrate a higher RSV in 1 M NaCI
that
contains an additional 0.1 % nonylphenol ethoxylate (NPE) surfactant than in 1
M NaCI
only. This phenomena, which shall be referred to as "RSV Ratio", is a dilute
solution
property specific to associative polymers containing hydrophobes, and does not
occur in
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linear, cross-linked, or branched polymers. The RSV Ratio is observed to
increase
dramatically with higher levels of hydrophobic monomer, and does not occur in
the
control polymer, Polyflex CP.3, or Polymer E. This phenomena is well
established in the
literature, and is explained as a binding of the hydrophobic domains with the
surfactant,
thus providing an increase in dilute solution viscosity or RSV.
TABLE S.1 Dilute Solution RSV Determinations
Ratio
- I
Polymer Monomer Feed RatioRSV RSV - RSV - RSV M NaCI
- DI 0.01 1 M - 1 : 1
(mole Water M NaCI NaCI - M NaCI aCl
%) - dL/g + +
M
dL/g dL/g 0.1 o
% 0.1
/ NPE
NPE
730 1 13 21 23 1.1
VIII (control)AM/AA 50/50
IX AM/AA/LMA 50/49.9/0.1990 106 12 20 1.7
X AM/AA/LMA 50/49.8/0.2700 23 2 15 1.5
X1 AA/AM/LA 50/49.75/0.25930 128 16 24 7.5
XII AA/AM/LA 50/49.5/0.5650 34 4 17 4.3
Polyflex AM/AA/** 40/60/** 580 47 l3 13 1.0
CP.3
Polymer AM/AA 50/50 1216 184 44 44 1.0
E
[Polymer dL/g .001 .005 .025 .025
Concentration
f
LA - Lauryl acrylate
LMA - Lauryl methacrylate
NPE - nonylphenol ethoxylate surfactant
** Polyflex CP.3 is crosslinked with an unknown monomer at an unknown level.
3. Retention and Draina eg_ Tests
A first series of Britt jar retention tests and Canadian Standard Freeness
(CSF)
drainage tests are conducted to compare the performance of the HAPs of the
invention,
with those of the following: a non-hydrophobic associative polymer; a
conventional
anionic polyacrylamide flocculant; and inorganic and organic drainage aids
commonly
referred to within the industry as "microparticles" or "micropolymers".
The Britt jar (Paper Research Materials, Inc., Gig Harbor, WA) retention test
is
known in the art. In the Britt jar retention test a specific volume of furnish
is mixed
under dynamic conditions and an aliquot of the furnish is drained through the
bottom
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WO 01/40578 PCT/US00/32820
screen of the jar, so that the level of fine materials which are retained can
be quantified.
The Britt jar utilized for the present tests is equipped with 3 vanes on the
cylinder walls
to induce turbulent mix, and a 76 q, screen in the bottom plate is utilized.
The CSF device (Lorentzen & Wettre, Code 30, Stockholm, Sweden) utilized to
determine relative drainage rate or dewatering rate also is known in the art
(TAPPI Test
Procedure T-227). The CSF device comprises a drainage chamber and a rate
measuring
funnel, both mounted on a suitable support. The drainage chamber is
cylindrical, fitted
with a perforated screen plate and a hinged plate on the bottom, and with a
vacuum tight
hinged lid on the top. The rate measuring funnel is equipped with a bottom
orifice and
a side, overflow orifice.
The CSF test is conducted by placing 1 liter of furnish, typically at 0.30%
consistency, in the drainage chamber, closing the top lid, and then
immediately opening
the bottom plate. The water is allowed to drain freely into the rate measuring
funnel;
water flow which exceeds that determined by the bottom orifice will overflow
through
the side orifice and is collected in a graduated cylinder. The values
generated are
described in millimeters (mls) of filtrate; higher quantitative values
represent higher
levels of dewatering.
The furnish employed in this first series of tests is a synthetic alkaline
furnish.
This furnish is prepared from hardwood and softwood dried market lap pulps,
and from
water and further materials. First the hardwood and softwood dried market lap
pulp are
separately refined in a laboratory Valley Beater (Voith, Appleton, WI) These
pulps are
then added to an aqueous medium.
The aqueous medium utilized in preparing the furnish comprises a mixture of
local hard water and deionized water to a representative hardness. Inorganic
salts are
added in amounts so as to provide this medium with a representative alkalinity
and a total
conductivity.
To prepare the furnish, the hardwood and softwood are dispersed into the
aqueous
medium at typical weight ratios of hardwood and softwood. Precipitated calcium
carbonate (PCC) is introduced into the furnish at 25 weight percent, based on
the
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WO 01/40578 PCT/US00/32820
combined dry weight of the pulps, so as to provide a final furnish comprising
80 % fiber
and 20 % PCC filler.
This first series of tests is conducted with the following: Polymer II, a
hydrophobically associative anionic polyacrylamide of the invention as
discussed herein;
S Polymer I, an unmodified anionic polyacrylamide control polymer as discussed
herein;
Polymer E, a high MW commercial anionic flocculant; Polyflex CP.3, a
commercial
polyacrylamide drainage aid (Cytec Industries, Inc., West Patterson, NJ); and
bentonite
clay, also commonly employed in the industry as a drainage and retention aid.
The Britt jar retention tests in this first series are conducted with 500 mls
of the
synthetic furnish, having a typical solids concentration of 0.5 %. The test is
conducted
at a constant rpm speed according to the following parameters, consistent with
the
sequence set forth in Table 2: add starch, mix; add alum, mix; add polymer
flocculant,
mix; add drainage aid, mix; obtain filtrate.
The cationic potato starch utilized is Stalok 600 (A.E. Staley, Decatur, IL),
and
the alum is aluminum sulfate-octadecahydrate available as a 50% solution
(Delta
Chemical Corporation, Baltimore, MD). The cationic flocculant utilized,
referred to as
CPAM-P, is a 90 / 10 mole % acrylamide / N,N-dimethylaminoethylacrylate methyl
chloride quaternized; this material is commercially available as a self
inverting water-in-
oil emulsion.
The retention values reported in Table 2 are fines retention where the total
fines
in the furnish is first determined by washing " 500 mls of furnish with 10
liters of water
under mixing conditions to remove all the fine particles, defined as particles
smaller than
the Britt jar 76 ~. screen. The fines retention for each treatment is then
determined by
draining 100 mls of filtrate after the described addition sequence, then
filtering the filtrate
through a pre-weighed 1.5 ~ filter paper. The fines retention are calculated
according to
the following equation:
Fines retention = (filtrate wt ~ iminus) fines wt)/filtrate wt
where the filtrate and fines weight are both normalized to 100 mls. Retention
values
represent the average of 2 replicate runs.
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The CSF drainage tests are conducted with 1 liter of the furnish at a solids
concentration of 0.30 %. The furnish is prepared for the described treatment
externally
from the CSF device, utilizing equivalent speeds and mixing times as described
for the
Britt jar tests, in a square beaker to provide turbulent mixing. Upon
completion of the
S addition of the additives and the mixing sequence, the treated furnish is
poured into the
top of the CSF device and the test is conducted.
In both Britt jar retention and CSF drainage tests, higher quantitative values
indicate
higher activity and a more desired response.
The data set forth in Table 6 illustrates the superior activity provided by
Polymer II
of the invention, as compared to the results obtained with unmodified control
Polymer
I and the conventional anionic flocculant Polymer E. Further, the polymer of
the
invention provides activity equivalent to that of bentonite clay and
approaching that of
Polyflex CP.3. The described material dosages are all based upon product
actives, unless
noted otherwise.
TABLE 6
ADD # 1 Ibs.ltonADD Ibs.ltonPolymer Ibs./tonDrainageLbs./tonAvg.CSF
# Aid
2
(active) (active) (active) (active)%. mls
Ret
Cationic 10 Alum 5 none 27.29395
Potato Starch
Cationic 10 alum 5 CPAM-P Flocculant0.5 none 0 48.43380
Potato Starch
Cationic 10 alum 5 CPAM-P Flocculant0.5 Polymer0.75 69.54620
Potato Starch II
Cationic 10 alum 5 CPAM-P Flocculant0.5 Polymer0.75 50.46535
Potato Starch I
Cationic 10 alum 5 CPAM-P Flocculant0.5 Polymer0.75 53.16540
Potato Starch E
Cationic 10 alum 5 CPAM-P Flocculant0.5 Polyflex0.75 77.85650
Potato Starch CP.3
Cationic 10 alum 5 CPAM-P Flocculant0.5 Bentolite4 64.72600
Potato Starch HS
A series of retention and drainage tests are conducted utilizing a pulsed
drainage
device (PDD). The test substrate, test conditions, and associated chemical
additives are
identical to those utilized in Table 6.
The PDD is equipped with a rotating hydrofoil, and vacuum capability
underneath a wire screen. It is an instrument developed internally (described
in U.S.
Patent No. 5,314,581) as a reasonable simulation of the actual retention,
drainage, and
sheet formation operations. During the operation of the experiment, a vacuum
is applied
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to the fibrous slurry to assist in the formation of a fibrous mat, and the
vacuum is
continued until a steady state equilibrium vacuum is achieved.
A variety of measurements can be taken with use of the PDD. For instance, the
PDD can be used in determining first pass retention, peak vacuum, equilibrium
vacuum,
peak to equilibrium vacuum ratio (PEVR), and vacuum drainage time.
The first pass fines retention is determined by mass balance calculations
involving the weight of the final sheet, the total mass introduced into the
PDD, and the
total fines fraction of the stock which is defined as the fraction of the
stock that has a
particle size less than 76 p. As with Britt jar fines retention, higher values
indicate the
desired response.
The peak vacuum is the total vacuum required during mat formation until air is
drawn through the formed mat and the vacuum is disrupted. Equilibrium vacuum
is the
steady state vacuum drawn through the formed sheet. Both peak vacuum and
equilibrium
vacuum are measured in inches of Hg. A lower quantitative value for the peak
vacuum
indicates a fibrous matrix that is easier to dewater.
The peak to equilibrium vacuum ratio (PEVR) is the unitless ratio of these two
outputs. Studies have demonstrated that this parameter is useful as an
indication of sheet
formation, in that lower PEVR values indicate more desirable or more uniform
sheet
formation.
The vacuum drainage time is the time to peak vacuum, and is measured by the
instrument in time units of seconds. It is believed this response is similar
to the wet-line
on a paper machine, which is the point where the water has drained
sufficiently such that
the sheet has lost its sheen or visible free water. The wet line position is
commonly
monitored as an indication of papermachine drainage. The desired responses for
the
vacuum drainage parameters are reduced (low) values, indicating improved
drainage.
The second series of drainage tests, utilizing the PDD, is taken with the same
drainage aids as the first series, except for the absence of bentonite. The
associated starch,
alum, and cationic flocculant are as described previously. The results in
Table 7 set forth
the values obtained for the above measurements from taking the PDD
measurements.
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These results demonstrate that Polymer II of the invention provides a
definitive
drainage dosage response. Specifically, as the dosage is increased, the
gravity drainage,
the peak vacuum, and the vacuum drainage times improve accordingly.
It is noted that unmodified control Polymer I and the conventional flocculant
Polymer E do not exhibit a dosage response. In this regard, as the dosage of
these
polymers is increased, the retention and associated drainage responses do not
increase or
decrease.
The improved drainage activity of Polymer II, as compared to that of control
Polymer I and Polymer E, is also clearly shown by the Table 7 data. Polymer II
provides
higher fines retention than Polyflex CP.3 and approaches the drainage activity
of Polyflex
CP.3, as 1.0 lb./ton of Polymer II provides about equal drainage to 0.5
lbs./ton of
Polyflex CP.3. It is noted that at these equal drainage times, the Polymer II
provides
lower PEVR values than Polyflex CP.3, an indication of improved sheet
uniformity or
formation.
TABLE 7
10 Lbs.lTon DOSAGE% Gravity VACUUM PEAK Peak Vacuum
Cationic Potato FirstDrainage to
Starch (Lbs.lT)Pass Time-secondsEquilibrium.VACUUMEquilibriumDrainage
+ 5 Lbs.ll'on Fines(mass (in (in Vacuum Time-
Aluminum Sulfate Hg) Hg) Ratio seconds
+0.5 Lbs./Ton Retentionmeasurement) (Vacuum
CPAM-P Flocculant
+ Drainage Aid Time)
No Drainage 0 89.09%3.25 3.61 5.15 1.43 1.028
Aid
Polyflex CP.3 0.5 93.47%3.04 2.97 4.44 1.49 0.679
Polvflex CP.3 0.75 95.10/2.99 2.71 4.07 1.50 0.622
Polvllex CP.3 1 95.37/3.01 2.65 4.01 1.51 0.608
Polymer 1 0.5 92.343.16 3.53 4.88 1.38 0.798
%
Polymer I 0.75 91.34%3.18 3.53 4.81 1.36 0.801
Polymer 1 I 94.74%3.13 3.52 4.81 1.37 0.778
Polymer II 0.5 96.05%3.09 3.27 4.66 1.42 0.731
Polymer II 0.75 95.83%3.05 3.10 4.53 1.46 0.685
Polymer II 1 95.64%2.91 3.01 4.43 1.47 0.673
Polymer E 0.5 93.31%3.14 3.50 4.81 1.37 0.793
Polymer E 0.75 92.10/3.18 3.43 4.78 1.39 0.786
Polymer E 1 94.21%4.67 3.43 4.83 1.41 0.792
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A series of Britt jar retention and CSF tests is conducted with the following:
Polymer III, hydrophobically associative anionic polyacrylamide of the
invention as
discussed herein; Polymers V - VII, hydrophobically associative polymers of
the
invention, exhibiting sequentially increased levels of hydrophobic
modification; Polymer
IV, an unmodified anionic polyacrylamide control polymer as discussed herein;
Polymer
E; and Polyflex CP.3. The tests are conducted according to the methods
previously
described. The data demonstrates the superior activity of the invention
provided by
Polymer III and Polymer VII, compared to the unmodified control Polymer IV.
Increased retention and drainage activity are observed with increased level of
hydrophobic substitution, with Polymer VII approaching the activity of
Polyflex CP.3.
The data is set forth in Table 8.
TABLE 8
1dd # I Ibo./too Add #y Iba/loo Add #A Iba./too Araioage Ibd/tor AvA. ISF
(acGce> lacoce) cache) Aid iactia) Rot.
IaGooic IA Aln 5 ITAAI-P 0.5 oooe 0 51.1 1A0
Potato Floccola,l
SIarcY
I'atiodc 1A Aln 5 ITAl1-P A.5 PolylkrCP.x O.iS ii.5 filA
Polate Flaccdaol
JlarcY
I'aliooic 10 ,11n 5 ITAlI-P A.5 Polner8 A.iS 195 i.11'
Potato Floccdaot
StarcY
I'atiooic IA Ah~ 5 ITAlI-P 0.5 PaIperIY 0.i5 It.O 51U
Potato Flxcolot
ltarcY
I'aliooic 10 Aln 5 LPAAI-P 0.5 Polper Y A.15 13.J 505
Potato Floccdul
SIarcY
I'aliooic to Alu 5 ITAl1-P A.5 PoI,rHrVi 0.75 55.1 515
polo Floccdaot
ltarcY
1'aliooic 1A Aln 5 ITAAI-PNacolatt A.5 PalyerVll 8.75 66.A 5N5
Potau
RIarcY
I'atiooic 10 Alu 5 ITAAI-PFloccdan 0.5 Polyerlll A.iS 69.0 filA
Potato
\larcY
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Another series of retention and drainage tests is conducted like the second
series,
with the PDD. The conditions and material are the same as employed for
previous series,
except that the drainage aids are as follows: Polymer III of the invention and
Polyflex
CP.3, as discussed herein; Polymer M, a commercially available high MW
polyacrylamide emulsion flocculant; and bentonite clay.
The polymeric materials are evaluated at 0.5, 0.75, and 1.0 lbs./ton active
polymer, while the bentonite clay is evaluated at 2, 4, and 6 lbs./ton, in
accordance with
typically utilized mill dosage levels. The results are set forth in Table 9.
The Table 9 data illustrates the activity of the polymer of the invention.
Polyflex
CP.3, bentonite clay, and Polymer III all exhibit positive dose response
activity, while
Polymer M is not dosage active. The Polymer III provides equal to greater
retention and
drainage activity as compared with bentonite clay.
Further as to the comparative activity shown in Table 9, Polymer M provides
retention and drainage equal to that of Polymer III, but at distinctly higher
PEVR; this
reduction in sheet uniformity / formation at equal drainage is undesirable.
The drainage
activity of Polymer III approaches that of Polyflex CP.3, as 1.0 lb./ton of
Polymer III
approaches the drainage of 0.5 1b. /ton Polyflex CP.3. It is again noted that
at these equal
drainage times, the PEVR of the polymer of the invention is lower than that of
Polyflex
CP.3, which is an indication of improved sheet uniformity or formation.
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TABLE 9
Lbs./TonDOSAGE %FirstGravity VACUUM PEAK Peak Vacuum
Drainage to
Cationic (Lbs.iT)Pass Time - EquilibriuVACUUM EquilibriumDrainage
seconds
Potato Fines (mass m (in Vacuum Time
Starch HG)
Retentionmeasurement)(in Ratio seconds
Hg)
+5 Lbs./Ton (Vacuum
Aluminum Timel
Sulfate
+0.5 Lbs./Ton
CPAM-P
Flocculant
+Drainage
Aid:
None 0 87.60%3.37 3.42 4.97 1.455 0.880
Polyflex 0.5 96.42%3.17 2.77 4.05 1.465 0.627
CP.3
Polyflex 0.75 98.81%3.30 2.61 3.84 1.472 0.577
CP.3
Polyflex I 97.65%3.18 2.49 3.70 1.486 0.515
CP.3
Polymer 0.5 95.39%3.28 3.00 4.32 1.440 0.672
III
Polymer 0.75 86.26%3.09 2.98 4.29 1.442 0.662
III
Polymer 1 95.54%3.09 2.91 4.22 1.451 0.649
III
Polymer 0.5 95.27%3.32 2.91 4.33 1.487 0.662
M
Polymer 0.75 95.80%3.22 2.74 4.18 1.523 0.649
M
Polymer 1 96.23%3.38 2.71 4.29 1.583 0.651
M
Bentonite 2 89.95%3.32 3.25 4.51 1.391 0.724
Clay
Bentonite 4 93.96%3.1 I 3.08 4.38 1.420 0.678
Clay
Bentonite 6 96.47%4.61 2.96 4.21 1.423 0.649
Clay
Another series of Britt jar retention and CSF drainage tests is conducted with
Polymer III and Polyflex CP.3, that utilizes higher levels of CPAM-P
flocculant and an
5 additional flocculant, polyvinylamine (PVAm). The PVAm is produced via
aqueous
solution polymerization of N-vinylformamide monomer, then with a subsequent
hydrolysis of the polymer to produce N-vinylamine. The subject polymer is
hydrolyzed
at 90%, such that the resultant copolymer is 90 mole % N-vinylamine / 10 mole
% N-
vinylformamide; the polymer is at S% solids and exhibits an intrinsic
viscosity in 1 M
10 NaCI of 3 dL/g. The data in Table 10 demonstrates the utility of the HAP at
higher levels
of CPAM-P flocculant, and activity with a PVAm flocculant.
42
CA 02390353 2002-05-07
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TABLE 10
Add #1 lbs./tonAdd Ibs.itonAdd #3 Ibs.itonDrainageIbs.~tonAvo. CSF
#2
(active) (active) (active)Aid (active)Ret.
Cationic 10 Alum p CPAM-P 0.5 none 0 53.6 370
Potato Flocculant
Starch
Cationic 10 Alum 5 CPAM-P 0.5 Polyflex0.75 78.6 650
CP.3
Potato Flocculant
Starch
Cationic 10 Alum 5 CPAM-P 0.5 Polymer 0.75 70.8 595
III
Potato Flocculant
Starch
Cationic 10 Alum 5 CPAM-P 1 none 0 66.6 395
Potato Flocculant
Starch
Cationic 10 Alum 5 CPAM-P t Polyflex0.75 91.6 680
CP.3
potato Flocculant
Starch
Cationic 10 Alum 5 CPAM-P 1 Polymer 0.75 80.9 61C
Ill
potato Flocculant
Starch
Cationic 10 Alum 5 PV Am 0.5 none 0 35.9 435
Potato Flocculant
Starch
Cationic 10 Alum 5 PV Am 0.5 Polyflex0.75 91.I 73(
CP.3
Potato Flocculant
Starch
Cationic 10 Alum 5 PV Am 0.5 Polymer 0.75 74.0 66.
III
Potato Flocculant
Starch
Another series of PDD experiments is conducted as presented in Table 11 under
the procedures described previously, with Polymer III, Polyflex CP.3, and two
additional
Polyflex products, Polyflex CS and Polyflex CP.2, also available from Cytec
Industries,
Inc. The data in Table 11 demonstrates that the inventive Polymer III provides
improved
retention and drainage activity compared to Polyflex CP.2, equivalent activity
as Polyflex
CS, and activity approaching Polyflex CP.3.
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CA 02390353 2002-05-07
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TABLE 11
Lbs./Tonlbs./ton%FirstGravity VACUUM PEAK Peak Vacuum
Drainage to
Cationic (Active]Pass Time - EquilibriuVACUUM EquilibriumDrainage
seconds
Potato Fines m (in Vacuum Time
Starch+5 HG) -
Lbs./Ton Retention (in Ratio seconds
0.5 Hg)
Lbs./Ton
CPAM-P
Flocculant
+Drainage
Aid:
None 0 85.2% 3.44 3.61 5.41 1.50 l
.
I
Polyflex 0.5 92.6% 3.12 2.77 4.28 1.55 0.64
CP.3
Polyflex 0.75 94.1% 3.09 2.52 3.97 1.58 0.55
CP.3
Polymer 1 93.5% 3.00 2.44 3.79 1.55 0.54
CP.3
Polyflex 0.5 91.6% 3.12 3.20 4.75 l .48 0.
CS 7
5
Polyflex 0.75 92.8 3.13 3.07 4.61 1.50 0.7.
CS %
PolyflexCS1 95.9% 3.20 2.92 4.47 1.53 0.6'
Polvflex 0.5 91.6 3.16 3.33 4.78 1.43 0.75
CP.2 %
PolyflexCP.20.75 92.7% 3.16 3.27 4.73 1.45 0.77
Polyflex 1 91.2 3.27 3.39 4.75 1.40 0.75
CP.2 %
Polymer 0.5 89.5 3.35 3.30 4.77 1.44 0.80
III %
Polymer 0.75 94.0 3.11 3.07 4.64 1.51 0.73
III %
Polymer I.00 94.3 3.13 3.01 4.57 1.52 0.68
III %
PolymerE 0.5 91.9% 3.14 2.97 4.60 I.55 0.70
Polymer 0.75 95.4 3.08 2.75 4.54 I .65 0.70
E %
Polymer 1 92.9 3.20 2.66 4.60 1.73 0.75
E %
A series of Britt jar retention and CSF drainage studies is conducted with the
brine dispersion polymers described previously. These studies set forth in
Table 12 are
5 conducted with Polymers IX and X, polymers of the inventive method modified
with
lauryl methacrylate; Polymers XI and XII, polymers of the inventive method
modified
with lauryl acrylate; Polymer VIII is the control polymer, produced under
equivalent
conditions as the hydrophobically associated polymers, but does not contain
the
hydrophobic substitution; Polyflex CP.3, and Polymer A, a conventional high MW
10 anionic polyacrylamide powder flocculant. The test conditions and
associated additives
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WO 01/40578 PCT/US00/32820
are as those described before, with the exception of the cationic flocculant
utilized being
CPAM-N; this material is equivalent in composition and physical form as the
previously
utilized CPAM-P. An anionic polyacrylamide flocculant (APAM) is also utilized.
This
material is a 30 mole % sodium acrylate / 70 mole % acrylamide copolymer,
commercially available as a self inverting emulsion. The data in Table 12
demonstrates
the improved activity of the inventive material. Polymers IX and XI
demonstrate high
retention and drainage activity compared to commercial drainage aid bentonite
clay, the
control Polymer VIII, and the conventional flocculant Polymer A. This improved
activity
is observed when utilized with a CPAM flocculant, with an APAM flocculant, and
without a flocculant.
CA 02390353 2002-05-07
WO 01/40578 PCT/US00/32820
TABLE 12
Add lbs./tonAdd lbs./tonAdd #3 Ibs./tonDrainageIbs.itonAvg. CSF
#1
(active)#2 (active) (active)Aid (active)Ret. Drainage
Cationic10 Alum 5 CPAM-N 0.5 None 0 53.6 370
Potato Flocculant
Starch
Cationic10 Alum 5 CP.4M-N 0.5 Polymer 0.75 71.1 630
VIII
Potato Flocculant
Starch
Cationic10 Alum 5 CPAM-N 0.5 Polymer 0.75 78.9 650
IX
Potato Flocculant
Starch
Cationic10 Alum 5 CPAM-N 0.5 Polymer 0.75 76.4 630
XI
Potato Flocculant
Starch
Cationic10 Alum 5 CPAM-N 0.5 Polymer 0.75 73.1 630
X
Potato Flocculant
Starch
Cationic10 Alum 5 CPAM-N 0.5 Polymer 0.75 555
XII
Potato Flocculant
Starch
Cationic10 Alum S CPAM-N 0.5 Polyflex0.75 86.0 680
CP 3
Potato Flocculant
Starch
Cationic10 Alum 5 CPAM-N 0.5 Polymer 0.75 68.1 620
A
potato Ftocculant
Starch
Cationic10 Alum 5 CPAM-N 0.5 Bentolite4 70.7 630
HS
Potato Flocculant
Starch
Cationic10 Alum 5 None 0 Polymer 0.5 59.6 560
VIII
Potato
Starch
Cationic10 Alum 5 None 0 Polymer 0.5 66.0 545
IX
Potato
Starch
Cationic10 Ahun 5 None 0 Polymer 0.5 67.8 555
XI
Potato
Starch
Cationic10 Alum 5 None 0 Polymer 0.5 52.0 495
X
Potato
Starch
Cationic10 Alum 5 None 0 Polymer 0.5 435
XII
Potato
Starch
Cationic10 Alum S None 0 Polyflex0.5 71.5 585
CP 3
46
CA 02390353 2002-05-07
WO 01/40578 PCT/US00/32820
Add #I Ibs.iton Add Ibs.;ton Add #3 lbs.UOn Drainage Ibs.!ton
Avg. CSF
(active) #' (active) (active) .4id (active) Ret. Drainage
Potato
Starch
Cationic 10 Alum ~ None 0 Polymer A 0.5 57.1 560
Potato
Starch
Cationic10 Alum 5 APAM 0.5 Polymer 0.5 530
VIII
Flocculant
Potato
Starch
Cationic10 Alum ~ APAM 0.5 Polymer 0.5 565
IX
Flocculant
Potato
Starch
APAM
Cationic10 Alum 5 Flocculant0.5 Polymer 0.5 540
XI
Potato
Starch
Cationic10 Alum 5 APAM 0.5 Polymer 0.5 540
X
Flocculant
Potato
Starch
Cationic10 Alum 5 APAM 0.5 Polymer 0.5 520
XII
Flocculant
Potato
Starch
Cationic10 Alum 5 APAM 0.5 Polyflex 0.5 630
CP 3
Flocculant
Potato
Starch
Cationic10 Ahtm 5 ADAM 0.5 Polymer 0.5 505
A
Flocculant
Potato
Starch
A series of evaluations is conducted on the PDD, utilizing equivalent methods
as
described in Table 12. The studies set forth in Table 13 are conducted with
Polymers IX
and X, polymers of the inventive method modified with lauryl methacrylate;
Polymers
XI and XII, polymers of the inventive method modified with lauryl acrylate;
Polymer VII
is the control polymer, produced under equivalent conditions as the
hydrophobically
associated polymers, but does not contain the hydrophobic substitution; and
Polyflex
CP.3. The data in Table 13 demonstrates positive drainage activity for
Polymers IX, X,
and XI compared to the unmodified control Polymer VIII. The Polymers IX, X,
and XI
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CA 02390353 2002-05-07
WO 01/40578 PCT/US00/32820
also indicate a positive dosage response at low PEVR, while the unmodified
control does
not demonstrate a remarkable dosage response.
TABLE 13
Ibs./tonlbs./ton%First Gravity VACUUM PEAK Peak Vacuum
Cat. Drainage to
Potato Starch(Active)Pass Time - EquilibriuVACUUM EquilibriumDrainage
+5 seconds
Ibs./ton
0.5 lbs./ton Fines m (in Vacuum Time
HG) -
CPAM-N Flocculant Retention (in Ratio seconds
Hg)
+ Drainage
Aid:
None 86.1% 3.98 3.33 5.11 1.53 0.94
Polymer 0.5 93.1% 3.76 2.89 4.38 1.52 0.67
VIII
Polymer I 95.6% 3.79 2.72 4.18 1.54 0.63
VIII
Polymer 0.5 93.7% 3.71 2.77 4.12 1.49 0.64
IX
Polymer 1 94.5% 3.64 2.51 3.75 1.50 0.54
IX
Polymer 0.5 92.5 3.69 2.79 4.12 1.48 0.65
X %
Polymer I 97.2 3.66 2.48 3.72 I .50 0.55
X %
Polymer 0.5 94.0 3.65 2.74 4.07 1.49 0.62
XI %
Polymer 1 93.7/ 3.68 2.49 3.87 I.55 0.54
XI
Polymer 0.5 86.0 3.86 3.23 4.69 I .45 0.77
XII %
Polymer 1 89.1 3.73 3.00 4.43 1.47 0.71
XII %
PolyflexCP.30.5 95.8% 3.70 2.60 3.93 1.51 0.57
Polyflex I 94.9 3.55 2.29 3.52 I .54 0.49
CP.3 %
It is noted that the foregoing examples have been provided merely for the
purpose
5 of explanation and are in no way to be construed as limiting of the present
invention.
While the present invention has been described with reference to an exemplary
embodiment, it is understood that the words which have been used herein are
words of
description and illustration, rather than words of limitation. Changes may be
made,
within the purview of the appended claims, as presently stated and as amended,
without
10 departing from the scope and spirit of the present invention in its
aspects. Although the
present invention has been described herein with reference to particular
means, materials
and embodiments, the present invention is not intended to be limited to the
particulars
disclosed herein; rather, the present invention extends to all functionally
equivalent
structures, methods and uses, such as are within the scope of the appended
claims.
48
