Note: Descriptions are shown in the official language in which they were submitted.
WO 2011/090672 PCT/US2010/061750
PROCESS FOR ENHANCING DRY STRENGTII OF PAPER BY TREATMENT Vv'ITII
VINY1:AMJNE-CONT.ATNING POLYMERS AND ACRY.L:AM.IDE-CONTAINLNG
POLYMERS
FIELD OF THE TNVENTTON
[0001,1 This invention relates to enhanced day strength in paper using a
process of
treating a pulp slurry with a combination of a vinylamine-containing polymer
and a cationic
or amphoteric acrylarnide-containing polymer.
BACKGROUND OF THE INVENTION
[0002] The papermaking industry is constantly seeking new synthetic additives
to
improve the dry strength of paper products. Improved city strength can give a
higher
performance product, but also may allow the paperanaker to use less cellulosic
fiber to
achieve a particular performance target. Furthermore, the increased usage of
recycled fiber
results in a weaker sheet, forcing the paperrnaker to either increase basis
weight of the sheet
or employ synthetic strength additives. The options that are known have
various economic
and technical limitations. For- instance, according to US Patent No.
6,939,443, the use of
combinations of po.lyaaniide-epichlorohycirian (PAE) resins with anionic
polyacrylamide
additives with specific charge densities and molecular weights can enhance the
cry strength
of a paper product. However, these. combinations also may elevate the wet
strength of the
resultant paper to the point that repulping broke paper is extremely difficult
and inefficient.
[0003] Polymers of acrylanaide or copolymers incorporating acrylamide and a
monomer such as cliallyldianethylamnaouiurta chloride. when treated with a
dialdehyde
compound such as glyoxal, are widely known to result in resins that can also
enhance the dry
strength of paper signilicantty, yet have very limited permanent wet strength
properties,
allowin the, papenuaker to easily rcparlp broke paper. However, these resins
also have their
limitations. These additives either have a very short sltelflife due to
viscosity instability, or
are shipped at very low active solids content. Furtlhermore, when added in the
larger
amounts, the performance of such dialdehyde-modified acrylamide-containing
polymers
tends to reach a plateau, making a high-perfornmance product difficult to
manufacture.
[0004] Polyvinylamine resins have become popular in the paperanmaking industry
not
only because they endow a sheet with increased dry strength, but also because
of their easy
WO 2011/090672 PCTIUS2010/061750
handling and application as well as the increased retention and drainage they
afford the paper
machine. However, when added in ever increasing amounts, they have the
negative effect of
overflocculating the sheet because of the heavy cationic charge these resins
carry.
Overflocculation results in a poorly formed, weaker finished product.
[0005] Other inventions have sought to augment the positive effects of
polyvinylamine. According to IUS Patent No. 6,824,650 and European Patent No.
1,579,071,
the combination of polyvinylamine with glyoxalated polyacrylamide resins in a
pulp slurry
results in enhanced product dry strength. However, the aforementioned
drawbacks of
glyoxalated polyacrylamides, namely low active solids of the product and
limited viscosity
stability of the product, are clearly in play.
[0006] -US Patent No. 6,132,558 discloses a paperniaking system wherein a pulp
slurry is treated first ;kith a highly cationic polymer, including vinylamine-
containing
polymers, of molar mass of 5,000 to 3,000,000 daitons, and subsequently with a
second
cationic acrylamidc-containing polymer of molar mass of more than 4,000,000
daltons,
subjected to a shearing stage, then treated. with a finely divided inorganic
flocculating agent,
such as bentonite, colloidal silica, or clay.
[0007] US Patent Publication 2008/0000601 discloses a process of papermaking
where the pulp slurry is treated with a polymer, including vinylamine-
containing polymers, of
molar tuass of more than 1,000,000 daltons, as well as a second polymer,
including cationic
ae;rylamide -containing polymers, with a molar mass of more than 2,500,000
daltons, all in the
absence of finely divided inorganic flocculating agents.
[0008] US Patent No. 6,746,542 discloses a method of papermaking wherein a
pulp
slurry is treated with starch that has been modified at a temperature above
the starch
gelatinzation temperature with a highly cationic: polymer, including
vinylamine-containing
polymers, of molar mass of less than 1,000,000 daltons. The pulp slurrv is
subsequently
treated with a second polymer, including cationic acrylamide-containing
polymers, with a
molar mass ofrnore than 1,000,000 daltons.
[0009] US Patent Publication 2008/0196852 discloses a retention aid system for
papernmaking which comprises at least one polymer, including vinylamine-
containing
polymers, at least one linear, anionic polymer of molar mass of more than
1,000,000 daltons,
and at least one particulate, anionic, crosslinked, organic polymer.
WO 2011/090672 PCTIUS2010/061750
[001()] Combining vinylamine-containing polymers with acrylamide-containing
polymers may he both the simplest and most effective means for producing a
high
performance paper product while maintaining paper machine productivity and
repulping
broke paper. However, examples from the prior art that may include these
polymers have
significant drawbacks. For instance, previous examples may require special
metering
apparatuses, additional steps for treating starch prior to addition to the
pulp slurry, or high
molar mass polymers that may result in over0oceulation of the pulp slurry when
added in
sufficient amounts to affect dry strength.
BRIEF DESCRIPTION OF THE IINIVENTION
[00111 Treatment of a p<,ulp slurry with a vinylarnine-containing aqueous
solution
polymer in combination with a cationic or amplioteric actylan~ide-containing
aqueous
solution polymers result in paper with enhanced dry strength.
[0012] This combination is most effective when the active polymer solids
content of
the acryl:amide-containing aqueous solution polymer ranges from Sig to 50% o
by weight, and
the content of the suns of the cationic and anionic monomers in the
acrylarnide-containing
polymer ranges from 5% to 50% on a molar basis of the total monomer content,
and the
molecular weight of the acrylamuide-containing polymer ranges from 75,000
daltons to
1,500,000 daltons.
[0013] The vinylamine-containing polymer is most effective when it contains at
least
50% on a molar basis of N-vinylformami.de monomer, at least 10% of which has
been
hydrolyzed in the feral product and has a molecular weight in the range of
from 75,000
daltons to 750,000 daltons. The aqueous solution containing the vinvlamine-
containing
polymer has a total polymer solids content of from 5% to 30% by weight,.
[0014] One embodiment of the invention is a process for the production of
paper,
board, and cardboard with enhanced dry strength comprising adding to the wet
end of a paper
machine (a) a vinylainine-containing aqueous solution polymer having a
molecular weight of
from 75,000 daltons to 750,000 daltons and (b) an amphoteric or cationic
acryl<unide-
containing aqueous solution polymer having a molecular weight of from 75.000
daltons to
1,500,000 daltons, where the sum of the anionic and cationic monomers comprise
at least 5%
on. a molar basis of the composition of the acrylamide-containing monomer.
3
WO 2011/090672 PCT/US2010/061750
[00151 In one embodiment of the process the vinylamine-containing polymer has
an
AT-vinylformamide content of at least 5044, on a molar basis of the total
monomer charged, at
beast I0% of Which has been hydrolyzed in the final polymer, and an active
polymer content
of from 5% to 30% on a weight basis.
[00161 in one embodiment of the process the acrylamide-containing aqueous
solution
polymer contains a sum cationic and/or amphoteric monomer charge of from 5% to
50% on a
molar basis, and has an active polymer content of from 5% to 50% on a weight
basis.
[0017] In one embodiment of the process the acs ~~lamide containi.ixg aqueous
solution
polymer is of an aqueous dispersion polynier.
[00151 In one embodiment of the process the acrylamide-containing aqueous
solution
polymer contains a cationic monomer charge of from 5% to 50% on a molar basis,
has an
active polymer content of from 54% to 50% on a weight basis, and comprises a
leas', one
cationic monomer selected from the group consisting of diallyldi-m
ethylarnmoniuni chloride
(DAD AAC), 2-(d imetliy[amino)ethyl aciylate, 2-(dimethylamino)ethyl
methacrylate, 2--
(diethyiaminoe.thyl) acrylate, 2-(diethylainino)ethyl ineethacrylate,
34dimethylamino)propyl
acrylate, 3-(diniethylamino)propyl methacrylate, 3-(diethylanlino)propyl
acrylate, 3-
(diethylamino)propyl niethacrylate, i-[3-(dimetlrylamino)propyllacrylanide, N--
[3--
(dimethylanrino)propyl]methacrylaniide, A~-[3-
(dietlry%larnino)propyl]acrylamidc, N-[3-
(diethylamino)propyllniethaci-ylamide, [2-
(acry;Ioyloxy)ethyl1trunnethylarnnroi.iu,7i chloride,
[2-(methacryloyloxy)eddy::]trimethyianimoniunm chloride, [3-
(acryloyloxy)propyltrime.thylanmmnium chloride, [3-11
(metlracrvloyloxy)propylltriniethylammoniurn chloride, 3-
(acrylainiidopropyl)trinretl.,ylaniinoniuin chloride, and 3-
(netliacrylam idopropyl)trimethylanunonium chloride.
[0019] In one. embodiment of the process the acrylamide- containing aqueous
solution
polymer has an overall aniphoteric charge.
[00201 In one embodiment of the process the amphoteric acrylamide-containing
aqueous solution is comprised of a polyelectrolyte complex consisting of an
acrylamide-
containing aqueous solution polymer and a cofactor carrying an opposing
charge,
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WO 2011/090672 PCT/US2010/061750
[0021 ] In one embodiment of the process the vinylamine-containing polymer and
the
acrylamide-containing polymer are a single product blend and the cationic
portion of the
anmphoteric acr lamide-containing polymer is generated by at least one monomer
selected
from the group consisting of dial lyldinrethylammonium chloride (DADIVIAC),
N..[3..
(din?ethylamni;?o)propyl]acrylamide, :'U-[3-
(diniethylan?ino)propyl:(methacryla?nide, V-[3-
((Iiethylanino)propyl]acrylamide, N-[3-((liethylap?ino)propyl]rnethacrylamide,
3-
(acrylamx?idopropyl)trinmethylanimoniuÃm. chloride, and 3-
(n?ethactylatnidopropyl)triniethylat??n?opium chloride.
[0022] In one embodiment of the process the vinylamine-co??taining polymer and
the
acrylamide-containing polymer are added to the wet end of a paper machine in a
ratio of
vinyia a?inc coirtaiuing polymer to ac~ylauride contain?ing polymer of from
10:1 to 1:50 up to
a sum total of 1.25% on a weight basis of the dry pulp, based on the active
polymer solids of
the polymeric products.
[0023] One embodiment of the invention is the paper product produced by the
process
of adding to the wet end of a paper machine (a) a vinylamine-containing
aqueous solution
polymer having a molecular weight of from 75,01;0 daltons to 750,000 daltons
and (b) an
an?pi}oteric or cationic acrylamide-containing aqueous solution polymer having
a molecular
weight of from 75,000 daltons to 1,500,000 daltons, where the sum of the
anionic and
cationic monomers comprise at least 5% on a molar basis of the composition of
the
acrylam?de-containing monomer.
[0024] hr another embocunient, the invention relates to the method. of
treating a
cellulosic pulp slurry in the wet end of a paper machine with (a) a
vinylanliirc. staining
polymer and (b) a cationic or amphoteric acrylamide-containing aqueous
solution polymer. it
is preferred that the vinylamine--containing polymer is added to the pulp
slurry first, followed
by the acrylainide-containing polymer.
DETAILED DESCRIPTION OF THE INVENTION
[0025] As used herein, the singular terms "a" and "the" are synonymous and
used
interchangeably with "one or more" or "at least one" unless the context
clearly indicates a
contrary meaning. Accordingly, for example, reference to "a compound" herein
or in the
appended claims can refer to a single compound or more than one compound.
[0026] As used herein and unless otherwise stated, the terms "vinylarine-
containing
WO 2011/090672 PCTIUS2010/061750
polymers," is tnrderstood to mean inonnopolymers of vinylamitne (e.g.,
polyvinylarnine or fully
hydrolyzedpolyvinyltorniamide}, copolymers of vinytarnine with other ct
nmoomeas,
partially hydrolyzed polyvinylformamide, partially hydrolyzed vinylformamid.e
copolymers,
Vinylamine terpolynier:s, vinylarnirnc home.- and copolymers manufactured by
the Hofmann
modification of acrylarnnide polymers, or virtylarnine containing polymers
that are chemically
modified after polymerization. Examples may include those described in US
Patent.
Publication number 2009/0043051 or number 2008/0196851.
[00271 As used herein and unless otherwise stated, the term "ac3ylaniide-
containing
polymer" refers to the cationic or amphoter-ic acrylamide-containing aqueous
solution
polymer.
[00281 As used herein and unless otherwise stated, the term "aqueous solution
polymer" refers to a polymer that forms a fully homogenous solution in water
when diluted to
I% on a dry solids basis, in the absence of any cosolvent. For instance, an
aqueous solution
polymer does not include oil-in-water or water-in-oil emulsions. Examples of
aqueous
solution polymers may include aqueous dispersion polymers, such as are
described in US
Patents 5,541,252 and 7,323,510 as well as US Patent Publications number
2002/198317 and
number 2008/0033094.
[00291 The invention is based in the discovery that the performance of a paper
machine and the paper products derived thereby can be greatly enhanced by the
treatment of
th.e pulp slurry with a vinylannin containing polymer in combination with an
acrylamide-
containing polymer with particular molecular weight and charge attributes as
described
below. Use of a vinylarmne-containing polymer alone provides both strength and
drainage
pe"fo-i mance in the papemiaking system; liovv'ever, when added in ever-
increasing amounts,
the performance of the paper product first levels oft, and then deteriorates,
largely due to
overflocculation of the forming paper web. It has une.xpec-tly been found that
the addition of
vinylamiae-containing polymer- in conjunction with the addition of aqueous
solution
acrtila.nido-co ntaining polymers having substantial amphoteric or cationic
charge results in a
product with strength performance beyond that which can be attained by using
vinylamine-
containing or aerylamide-containing polymers alone; moreover, the excellent
drainage
performance achieved by using a vinyÃamine-containing polymer can be
substantially
maintained using such a combination of polymers.
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WO 2011/090672 PCT/US2010/061750
[0030j The vinylarnine-containing polymer is most effective when its molecular
weight is from 75,000 daltons to 750,000 daltons, more preferably of from
100,000 daltons to
600,000 daltons, most preferably of from 150,000 daltons to 500,000 daltons.
The molecular
weight can be from 150,000 daltons to 400,000 daltons. Below the molecular
weight
threshold of 75,000 daltons, little to no strength performance is observed,
and substantial
drainage performance enhancement is not observed. The vinylarmine-containing
polymer is
not cooked with starch prior to addition to the pulp slurry. A vinylanine-
containing polymer
above the molecular weight of 750,000 daltons will generally negatively affect
formation at
dosages required for dry strength enhancement because of the tendency to
overllocculate the
sheet, resulting in lower strength. An. aqueous solution vinylarnine-
containing polymer above
750,000 daltons either is typically made at such high viscosities as to render
product handling
extremely difficult, or alternatively is made in such low product polymer
solids as to render
the product not cost effective to store and ship.
[00311 The active polymer solids percentage of the vinylarnine-containing
polymer
ranges of from 5% to 30%, more preferably from l % to 20% by weight of the
total
vinylarnine-containing polymer product content. Below 5%:% active polymer
solids, higher
molecular weight aqueous solution polymers may be possible, but the product
becomes
ineffective with respect when shipping and transportation costs are accounted
for. On the
other hand, as the active polymer solids rises, the molecular weight of the
polymer must
decrease overall so that the aqueous solution is still easily pumpablc. Thus,
a practical
relationship can be drawn/ between the total polymer solids of the
virryhrrnirre containinf;
polymer product and the molecular weight of such a poly.ner, and a correlation
can be drawn
between these parameters and polymer performance.
[0032 i l:he performance of the vinylamine-containing polymer is influenced by
the
amount of primary amine present in the product. The vinylarnine moiety is
typically
generated by acidic or basic hydrolysis of N" vinylacylarnide groups, such as
N-
vinylformamide, N-vinylacetamide, or 11r-vinyl propionaFnide, most preferably
N-
viny1formamicle. The vinylarnine-containing polymer is most effective in
enhancing the dry
strength of a paper product and/or the drainage performance of a papermaking
system when
the amount of N'-vin 1formamide is at least 50% on a molar basis of the
hydrolyzed polymer.
After hydrolysis, at least 10% of the N-vinylforrnamide originally
incorporated into the
resultant polymer should be hydrolyzed. Without wishing to be bound by theory,
the
hydrolyzed N-vinylforzmamide group may exist in various structures in the
final polymer
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WO 2011/090672 PCT/US2010/061750
product such as primary or substituted amine, amidine, guanidine, or amide
structures, either
in open chain or cyclical forms after hydrolysis.
[0033) The acrylamide-containing polymer is most effective when it contains a
substantial amount of a positively charged conronomer(s). Without wishing to
be bound by
theory, the positively charged monomer allows the acrylamide-containing
polymer to adhere
to the cellulose fibers due to a charge-charge interaction with negatively
charged substances
in the pulp slurry, including, but not limited to: pulp fibers, hemicellulose,
oxidized starch
commonly found in recycled cellulose funaish, anionic strength aids such as
carboxymethylcelhdose, and anionic trash. The incorporation of cationic groups
into the
acrylarnide-containing polymer is generally not detrimental to the drainage
performance of
the paperniaking system. Without wishing to be bound by theory, the hydrogen-
bonding
components of the acry laniide-containing polymer, such as amide groups, are
effective in
enhancing the dry strength of the paper product.
[0034j Suitable cofnononiers used to impart cationic charge to tile. polymer
include,
but are not limited to, diallyldirnethylanimoniuni chloride (DADMIAC), 2-
(dimethylamino)ethyl acrylate, (dig iethylaniii;o)ethyl ntethacrylate, 2-
(diethylaminoethyl)
acrylate, 2-(diethylatnino)ethyl nmethacrylate, 3-(dimetliylamino)propyl
acrylate, 3-
(dimethylamino)propyl meihacrylate, 3-(dieth_ylamino)propyl acrylate, 3-
(dii t?tylarnino)itropyl rnethacrylate, ,~% [3
(diitlethylariiino)prc>l;yl]aerylanaide, I [3
(dime.thylamino)propyl]methaciylamide, N t -(dietliylamino)propyljaerylanncle,
(diethylanrino)propyI)methacryla:nide, [2-
(acryloyluxy)ethyljtrirnethylam;noniuIn chloride,
[2-(anetlracryloyloxy)etlt}~l]trirnethylarrunoniuur chloride, [3-
(acry loyloxy)p-opyljtrimethylanmmtnaium chloride, [3-
(tnetliacryloyloxy)propyljtrimethiylammmiiiunt chloride, 3-
(acrylanridopropyl)trirnethylainmonium chloride, and 3-
(rnethacrylarnidopropy1)trimethylamrnoniLit' a chloride. Such cationic
monomers Can affect.
the performance of the cationic or arnphoteric polymer when incorporated into
the polymer
backbone.
[0035.1 The amount of cationic monomer incorporated into a polymer may be from
5% to 50% on a molar basis of all the monomers incorporated into the
aacrylamide-containing
polymer in the case of a cationic polymer. In the case of an amphoteric
polymer, the amount
of the cationic monomer plus the amount of an anionic monomer described below
may be
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WO 2011/090672 PCT/US2010/061750
from 515; to 50`.%;, more preferably from 15% to 40%, on a molar basis of all
the monomers
incorporated into the acrylarnide-containing polymer. The acrylamide-
containing polymer
may be cross-linked with an agent such as methylene bisacrylainide (NIBA)
provided the
molecular weight and charge guidelines are met as described herein.
[0036] The incorporation of an anionic con-ionomer into the acry lamide-
containing
polymer along with the cationic comonomer, forming an aniphoteric acrylarnide-
containing
polymer, is also effective in enhancing the dry strength of a paper product
made thereby.
Without wishing to be bound by theory, the anionic corooromer allows the
ampl:oteric
polymer to forin a coacervate complex with a wide variety of substances fotmd
in a recycled
pulp shun-y, including, but not limited to: a vinylamine-containing polymer, a
cationicaily
charged flocculant or coagulant, cationic or amphoterie starch, polya
midoarriine
epichlorohydrhi wet strength aids, or another amphoteric acrylamide--
containing polymer.
Moreover, the combination of cationic and anionic monomers in the acrylarnide-
containing
polymer either enhances or does not negatively affect the drainage performance
of a
papermaking system when compared to an acrylaniide-containing polymer using
only an
anionic coniononner. Suitable anionic conionomers include, but are not limited
to, acrylic
acid, inethacrylic acid, itneonic acid, itaconic anhydride, rnaleic anhydride,
rnnleie acid,
styrene sulfon:tafe, vinyl sralfonate, 2-acrylan ado 2 niethylpropane
sulfonate (AMPS).
Alternatively, such substructures may be generated by hydrolysis of a
precursor stnicture
(e.g. generation of inethacaylic acid in the polymer backbone via hydrolysis
of methyl
n:rethacrylate af}er the formal polyrnerizatiorr). The amount ofcharged
monomer
incorporated into the a,,rylanridc-containing polymer May affect the
performance of the
polymer. Such anionic monomers may be used in an anrphoteric acrylamide-
containing
polymer, and the amount of the anionic monomer plus the amount of a cationic
monomer
described above may be from 5% to 50% e on a molar basis of all. t e
moiririners incorporated
into doe acrylamida-containing polymer. The acrylarnide--containing polymer
may be cross-
linked with an agent such as nrethyiene bisacrylaniicie (MBA) provided the
molecular weight
and charge guidelines are motet as described herein.
[003-7] The properties of an amphoteric aqueous solution acrylarnide-
containing
polymer as defined above can also be effectively produced by the use of an
acrylarnide-=
containing polyelectrolyte complex. When combined with a vinylaniine-
containing polymer,
such an acrylarnide-containing polyelectrolyte complex may also produce
benefits similar to
those described above. when vinylainine-containing polymers are combined with
cationic or
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WO 2011/090672 PCT/IJS2010/061750
amphoteric acrylamide-containing polymers. Although polyelectrolyte complexes
in various
forms have been disclosed, such as in European Patent Publication No-
1,918,455 Al, herein
we disclose the unexpected result that the effectiveness of such
polyelectrolyte complexes in
generating dry strength beyond what the polyelectrolyte complex may provide on
its own,
may be achieved when they are used in combination with vinylamnine-containing
polymers.
An acrylaside-containing polyelectrolyte complex contains an acrylamide-
containing
polymer of either cationic, amphoteric, or anionic charge, as well as a second
polymer of a.
complementary charge. For example, an anionic ac ylamide-containing polymer
made by
polymerization of acrylarnide with one of the suitable anionic monomers listed
above can
form a polyelieetrolvte complex with a cationic polymer, which may or may non
include
acrylannide. Such cationic polymers include, but are not limited to,
allylamine-
epichlorohydrin polymers, cationic acrylamide--containing polymers as
described above,
polyarnutoatnire-elnicinloralrydrin polymers, aodpolyethyl~neimine polymers.
The
acrylamide-containing polyelectrolyte complex may also comprise a cationic
acrylamide-
containin polymer and an anionic polymer. Such anionic polymers include, but
are not
limited to, polymers and copolymers of (meth)acrylic acid, polymers and
copolymers of
tnaleic acid, and carboxymethyl cellulose. The acrylannide-containing
polyelectrolyte
complex may be added to the papermaking slurry either as a single blended
product or as two
separate products, most preferably as a single blended product. The amphoteric
polyelectrolyte complex carries a net charge, expressed in milliegnivalents
per gram (meq/g)
of polymer active content. The amphoteric polyelectrolyte complex is generally
most stable
and useftal in combination with vinylamine-containing polymers when the net
charge is in the
range of from -2 meq/g to 1-2 cneglg, more preferably of from -1 mecllg to -t-
1 inteq/g. The
particle size is also an important parameter of the amphoteric polyclecarolyte
complex. The
complex is most useful when the particle size ranges of from 0.1 microns to 50
microns, more
preferably from 0.2 to 5 microns. Other guidelines for active polymer solids,
the preferred
methods for adding the acrylarnide-containing polviner to the pulp slurry, and
the ratio of the
vinylanmiac=containing polymer to the acrylautide-containing polymer apply to
the total
formulation of the actylamide-containing polyelectrolyte complex, not only the
acrylamide-
containing polymer portion of the complex.
[0038] The act.ylamide-containing aqueous solution polymer, whether it is
characteristically a cationic polymer, amphoteric polymer, or amphoterie
polyelectrolyte
complex as defined above, most effectively enhances the dry strength of a
paper product
WO 2011/090672 PCT/US2010/061750
when its molecular weight is greater than 75,000 daltons. A molecular weight
less than
75,000 daltons is not easily retained in the sheet, and above all does not
endow paper with
significant dry strength properties, although it could be manufactured in such
a way is to have
a polymer solids content above 50% on a % eight basis. However, an acrylamide-
containing
polymer of greater than 1,500,000 daltons, and especially greater than
2,500,000 daltons may
shove significant drawbacks. Although at lower dosages, such high molar mass
polymers
may give wood drainage performance, attaining high dry strength typically
requires higher
dosages of polymers. Such a polymer can significantly overflocculate the sheet
when added
at a dosage that might significantly impact dry strew-igth, thereby resulting
in poor formation
anchor poor dry strength. to one embodiment, the molecular- weights of the
cationic or
amphoter-ic acrylan,ide-containing aqueous solution polymers can be in the
range of from
7 5,000 to less than 1,500,000 daltons, or can be from 100,000 to less than
1,250,000 daltons,
or can be from 100,000 to less than 1,000,000 daltons. Moreover, it polymer of
this molecular
weight is generally synthesized via emulsion or reverse emulsion
polymerization, thereby
adding significant cost, inconvenience, and environmental and safety risk. For
instance, oil
or other hydrocarbon, such as mineral oil, is required in the formulation of a
reverse emulsion
product which acids significant cost to the product but does not by itself add
value to the
product; significant additional make-down equipment used to store, agitate,
dilute, and invert
the emulsions; additional chemicals are needed to break or invert the
emulsion; and
emulsion- or reverse elnillsion-type polymers also contain significant amounts
of Volatile
organic cotnpounds, creating a significant health arcdior safety hazard. An
aqueous solution
aeaylamide-containing polymer of molecular weight greater than 1,500,000
daltons may in
theory be achieved in a product; however, such a product would likely be less
than 5%
o
polymer -solids, rendering= such a product less useful, cost effective, and
convenient to a
papernial e-r, or would be made be of such a high viscosity that the product
handling would be
extremely difficult. Thus, a practical relationship between the total polymer
solids and
molecular weight generally exists and a general correlation can be drawn
between these
parameters and polymer performance.
[0039] in one embodiment, the acrylamide-ecntai.ning polymer is an aqueous
dispersion polymer. Acrylamidc-containing polymers made by way of aqueous
dispersion
polymerization of either a cationic or anlphoteric nature are of special
practical importance
when combined with vinylamine -cotitainirtg polymers. Specific examples are
described in
U'S Patent No. 7,323,510 as well as US Patent Publication No. 2008,0033094. `
hese aqueous
ii
WO 20111090672 PCT/17s2010/061750
solution polymers may have molecular weights of from 300,000 daltons to
1,500,000 daltons,
or from 400,000 daltons to less than 1,250,000 daltons, while maintaining
polymer solids
content of from. 10% to 50% on a weight basis. These polymers are of a
molecular weight
that is somewhat less than traditional flocculants, and are thus less
effective than higher
molecular weight acryla.nide containing polymers as retention and drainage
polymers at low
dosage levels, but may generate excellent drainage performance when used at
dosage levels
adequate for dry strength enhancement without overffiocculating a forming
cellulosic sheet.
Without wishing to be bound by theory, the interaction ofvinylansi,_e.--
containing polymers
either with aqueous dispersion aezvlamide-containing polymers or with other
components of
a paperrnaking system including but not limited to oxidized starch,
heanicellulose, or anionic
trash. may create especially extensive hydrogen-bonding networks, providing
additional dry
strength to a paper product without any substantial negative effects On the
drainage
performance of the papermaking system.
[00401 The viny lamine-containing polymer and the acrylamide-con taiflirt g
polymer
may be combined together in a single.-prod.iuct blend. Ratios of the
vinylamine-containing
polymer to the acrylamide containing polymer range of from 10:1 to 1:50, more
preferably in
the range of fi=oni 5:1 to 1:10, more preferably in the range of from 3:1 to
1:5, most preferably
in the range of from 2:1 to 1:4.
[00411 Total amounts of the polymer blend may be added to the pulp slurry in
the wet
end of the paper machine in amounts of from 0.05% to 1.25% of the weight of
dry pulp on a
total polymer solids basis. Blends can be made with vinylamine containing
polymers and
either cationic or amphoteric acrylannide-containing polymers, but most
preferably with
cationic. acrylamide-containing polymers. Withoutwrishing to be hound by
theory, annionic
components of amphoteric a iylalnide-containing polymers may interact in all
ionic fashion
with cationic components of vinylatnine-c(ntaisningpolymers, particularly
primary amine
groups, to form gels and hi h viscosity products that are not useful for paper-
naking.
Without wishing to be bound by theory, polymers containing cationic monomers
with ester
groups, for example, 2- [(acryloyloxy)ethyl;ltricnethylamrnonirrni chloride,
can react in
aqueous solutions with primary amine groups in the vinylamine-containing
polymer to form
amide groups, or can hydrolyze to generate the above-mentioned anionic
moieties, either of
which may form a gelled or prohibitively high viscosity product which is not
useful in
papernraling. Moreover, the hydrolysis of the relatively expensive cationic
acrylate group
represents a significant financial loss when considering the cationic
aciylanii.de-containing
12
WO 2011/090672 PCT/US2010/061750
polymer. Without wishing to be bound by theory, amide-containing cationic
monomers, such
as 3-(a cry] arrtidopropyl)trime thylarTmonium chloride or
diallyldintethylamrnouiurrt chloride
(1:3A_DivMAC) are resistant both to hydrolysis in aqueous solutions as well as
reaction with
primary amine groups, making them preferred as cationic monomers in the
aciylamide-
containing polymer to be blended with the vinylamine-containing polymer.
[0042] Vitrylaraine containing polymers and acrylamide-containing polymers can
be
added during the papermakinz process in the wet end either in the thick stock,
or in the thick
stock; either before or after a shear point. The acivlamide-con taining
polymer may be added
first in the wet end of the paper machine, followed by the vinylaminc-
containing polymer; the
acrylamide-containing polymer may be added at the same point separately in the
wet end of
the, paper machine as the vinylaniine-containing polymer; the acaylamide-
containing polymer
may be added at the same point in the wet end ofa paper machine as a single
product 'blend;
or, more preferably, the yinyfamine-containing polymer may be added first in
the wet end of
the paper machine, followed by the acrylamide-containing polymer. The
vinylantine-
containing polymer is not reacted with starch prior to addition to the pulp
slurry.
[0043] The vinylainine-containing polymer and the acrylarnide-containing
polymer
may be added to the wet end of a paper machine in a ratio of from 1:50 to 10:1
of
vinylarnine-containing polymer to acrylamide-containing polymer as a ratio
ofpolyrier
solids; more preferably in a ratio of from 1:10 to 5:1, more preferably in the
range of from
1:5 to 3:1, most preferably in the range of from 1:5 to 2:1. Total amounts of
the polymer
blend may be added to the pulp slurry in the wet end of the paper machine in
amounts of
0.05% to 1.2534% of the weight of dry pulp on a total polymer solids basis.
[0044] In another embodiment, this invention can be applied to any of the
various
grades of paper that benefit froni enhanced dry strength including but not
limited to
linerboard, bag, boxboard, copy paper, container board, corrugating medium,
file tbdder,
ttewsprirtt, paper board, packaging board, printing and writing, tissue,
towel, and publication.
These paper grades can be comprised of any typical pulp fibers including
groundwood,
bleached or unbleached Kraft, sulfafe, semi-mechanical, mechanical, semi-
chemical, and
recycled. They may or may not include inorganic fillers.
[0045] The embodiments of the invention are defined in the following Examples.
It
should be understood that these Examples are given by way of illustration
only. Thus various
modifications of the present invention in addition to those shown and
described herein will be
13
WO 2011/090672 PCT/US2010/061750
apparent to those skilled in the art from the foregoing description. Although
the invention
has been described with reference to particular means, materials and
embodiments, it is to be
understood that the invention is not limited to the particulars disclosed, and
extends to all
equivalents within the scope of the appended claims.
EXAMPLES
[0046:1 Polyvinylamine is abbreviated as PVAm. Size exclusion chromatography
(SEC) was used to measure molecular weight. The analysis was accomplished
using gel
permeation columns (CATSEC 4000 + 1000 + 300 + 100) and Waters 515 series
chromatographic equipment with a mixture of 1 % NaNO3/0.1 '%o Trifluoroace.tic
acid in
50:50 H20:CIIC7jNI as the mobile phase. The flow rate was 1.0 mL/nlin. The
detector was a
Hewlett[ Packard 1017A differential refractometer. Column temperature was set
at 40 C and
the detector temperature was at 35 `C. The number average (elfõ) and weight
average
molecular weight (,'IA,) of the polymers were calculated relative to the
commercially available
narrow molecular weight standard poly(2-vinyl pyridine).
[0047] The net charges or charge densities (Miitek) of the ionized polymers in
the
present invention were measured at pH 7.0 using a colloid titration method.
Charge density
(meq/g) is the amount of net charge per unit weight, in miliiequivalents per
grain of active
polymer. The polymer sample is titrated with a titrant of opposing charge. For
net cationic
polymers, the titrant used is potassium polyvinyl sulfate (PVSK), and for net
anionic
polymers the titrant used is polydimethyldiallylammonium chloride (DADMAC).
The titrant
is added until a 0 mV potential is achieved using an autotitrator (Brinkmann
Titriuo) at a
fixed titration rate (0.1 ml./dose, 5 sect and a tvlatek particle charge
detector (Model PCD 03,
ETC, Mtitek Analytic Inc., 3141 Kingston Ct., :Marietta, GA, USA) signifying
end point
detection.
[0048] Linerboard paper was made using a paperrnaking machine. The paper pulp
was a 100 % recycled medium with 50 ppm hardness, 25 ppm alkalinity, 2.5 % GPC
D1SF
oxidized starch (Grain Processing Corp., Muscatine, TA) and 2000 uSicm
conductivity. The
system pH was 7.0 unless indicated otherwise, and the pulp freeness was about
380 CSF with
the stock temperature at 52 "C. The basis weight was 100 IN per 3000 fat.
Unless otherwise
indicated, Stalok 300 cationic starch (fate & Lyle PLC, London, UK) and
PerFornr'~z PC
8713 floeculant (Hercules Incorporated, Wilmington, DE) were added to the wet
end of the
paper machine in the amount of 0.5% and 0.0125% of dry pulp, respectively.
Vinylamine-
14
WO 2011/090672 PCT/US2010/061750
containing and acrylam ide-containing polymers as described in the above
examples were
added as dry strength agents to the wet end of the paperniaking machine at the
indicated
levels, expressed as a percentage of weight of polymer active versus dry paper
pulp. It is
generally accepted that the dosages typically used for dry strength polymers
on the pilot
paper machine are much greater (i.e. at least double) what a commercial paper
machine may
use. Ring crush, dry Mullen burst, and dry tensile tests were used to measure
the dry strength
effects. All city strength results are expressed as a percentage of the dry
strength of paper
made without a dry strength resin.
1-00491 Drainage efficiency of the various polymeric systems was compared
using one
of two tests. One test is the Canadian Standard Freeness (CSF) Test. The dose
of polymer
active varied as is indicated in the tables. The results are sununarized in
the following tables
and the drainage performances of these compositions are expressed as
percentage increase
over the blank.
[00501 Another method for evaluation of the performance of the drainage
process is
the vacuum drainage test (VDT). `.the device setup is similar to the Buchner
funnel test as
described in various filtration reference books, for example see Ferry's
Chemical E'ngineers'
Handbook, 7th edition, (McGraw-Hill, New York, 1999.) pp. 18-78. The VDT
consists of a
300-ml magnetic Gelman filter funnel, a 250-ml graduated cylinder, a quick
disconnect, a
water trap, and a vacuum pump with a. vacuum gauge and regulator. The VDT test
was
conducted by first setting the vacuum to 10 inches Hg, and placing the funnel
properly on the
cylinder. Next, 250 g of 0.5 wt. % paper stock was charged into a beaker and
then the
required additives according to treatment program (e.g., starch, vinylarnine-
containing
polymer, actytamide-containing; polymer, locculants) were added to the stock
under the
agitation provided by an overhead mixer. The stock was then poured into the
filter funnel and
the vacuum pump was turned on while simultaneously starting a stopwatch. The
drainage
efficacy is reported as the time required to obtain 230 nil, of tiltrate. The
results of the two
drainage tests were normalized and expressed as a percentage of the drainage
performance
observed versus a system that did not include the vinylatnine-containing and
acrylamide.-
containing polymers.
[0051, Polymer A is a vinylatnine-containing polymer such as Hercobond % 6363
(available from Hercules Incorporated, Wilmington, DE) with a molecular weight
in the
range of 100,000 daltons to 500,000 daltons with an active polymer solids
content of 9% to
WO 2011/090672 PCT/US2010/061750
15%, an N-vinylforma_nide charge off om 75% to 100%, with a range of
hydrolysis from
50% to 100%.
[00521 Polymer B is a vinylamine-containing polymer such as such as flercobond
6350 (available from Hercules Incorporated, Wilmington, DE) with a molecular
weight in the
range of 100,000 daltons to 500,000 daltons with an active polymer solids
content of 9% to
15%, an N-vinylformamide charge of from 75% to 100%, with a range of
hydrolysis from
301,/0 to 75%.
[00531 Polymer C is an amphotÃ;ric acrylaniide containing polymer such as
Hereobond 1205 (available fivm Hercules Incorporated, Wilmington, DE) smith a
molecular
weight in the range of 100,000 daltons to 500,000 daltons with an active
polymer solids
content of 10% to 25% and a sure total monomer charge of anionic and cationic
monomers of
from 8% to 20% of the total monomer charge.
[0051] Polymer t) is a cationic acrvlanride containing polymer such as
Hercobond
1200 (available from Hercules incorporated, Wilmington, DE) with a molecular
weight in the
range of 100,000 daltons to 500,000 daltons, an active polymer solids content
of 10% to 25%n
and a cationic monomer charge of 20% to 40%.
[00551 Comparative Polymer E is an anionic acrylamide-containing polymer such
as
Hercobond 2000 (available from Hercules Incorporated, Wilmington, DE) with an
anionic
monomer charge in the range of from 5% to 20%.
[0056] Polymer F and Polymer C are cationic acrylamide-containing aqueous
dispersion polymers such as Praestaret 1(325 and 3(350, respectively
(available from
Ashland Inc., Covington, KY) with a molecular weight it, the range of 500,000
daltons to
1,500,000 daltons, an active polymer solids content of 20"+, to 45% and a
cationic monomer
charge of 10% to 40%.
[0057.1 Polymer 1-1 is an amphoteric acrylarnide-containing polyelectrolyte
complex
such as HercohondQ? 1822 (available from Hercules incorporated, Wilmington,
DL) with a
molecular weight in the range of 100,000 daltons to 500,000 daltons with an
active polymer
solids content of 10% to 25%, and a net charge of from -2 mneq/g to 2 n?egi'g.
[0058] Polymer K is a cationic acrylamrmitle-containing polymer such as
Praestamin
Cf., (available from Ashland Inc., Covington, KY) with a molecular weight in
the range of
16
WO 2011/090672 PCT/U52010/061750
100,000 daitons to 400,000 daitons with an active -polymer solids content of
15% to 30x1,.
The cationic coznononler in Polymer K is 3-(acrylanridopropyl)lri-
urelllylaliunoln.ium chloride.
Polymer K. can be blended with vinylamine-containing= polymers such as Polymer
A and
Polymer B to form a single product.
EXAMPLE I
[005911 Table 1 shows the results or a pilot paper machine trial using Polymer
A,
airpholeric Polymer C. and cationic Polymer D. Thy nil of the system was
adjusted to 6.5.
Alum (Croydtnr, PA) and HipHase 35 rosin sire (Hercules, Inc., Wilmington, DE)
were used
in the amount of 0.5% and 0.3% of dry pulp, respectively. OptiPlus 1030
amphoteric starch
(National Starch, Bridgewater, N.J) was added in the place of Stalok 300
cationic starch, still
used at 0.5% of dry pulp.
Table 1. Strength and drainage properties of paper made with Polymer A and an
acrylaenidc
containing polymer.
Entry Add lire I `:u Additive 2 % Dry `t'ensile Dry Mullen Burst Xing, Crosh
Drainage
100 100 100 1(10
Polymer A 0.050 -- 102.4 106.2 105.7 1 i 0
..................... ----------- -----------------
.............................. ........................ 3 Polymer%, 0.125 -- -
103.2 110.1. ?08.7 131
4 -- Polymer C 0.100 104.5 105. 104.8 107
-- I olymer C 0.250 163.5 i 13.0 110.1 11 e
6 Foly er A 0.090 Polyrorr C 0.100 1618 108.0 1110-4 121
.._.._........-_..-.._.......-_ -
...................._............._....._.........._...._............._...__...
.....__..._........__.....
7 Polymcr A 0.125 Polymer C 0.100 11-.8 i 16.S 112.E 142
8 Polvu,er A 0.088 Polymer C 6-175 106,5 i I2.7 117.5 137
--------------- --------------------- ............. - .......... ...._...------
---- .... ......
9 Polymcr: A 0.05(1 1'oiS'r.icl'C. 6.250 11 )s :011).2 114.2 121
(0 Polyaacc A 0. i 25 Polymer t `. 0-250 108.9 121,0 1111).9 153
_2-9,
11 .......... ---....... ....... _.------ --Polymer-- .1_7 . _.. 0_.._....----
-----103--- .2 - -- 9-3-1 ----------------...._.Ø4..6 ---------_----_1.9
.. .100 1
12 -- Polvune-r D 0.250 106.5 106.2 109.9 150
-- ---- - ------------------------.... ----------..... .......... ....--------
------------------- ----- -------..-..--; -- ....
13 PolymcrA 0.05(1 Polymer)) 0.100 1103.2 98.2 107.0 137
14 Polyne:rA 0.125 PolymÃri) 0.1.00 105.1 1083 111.4 137
----------------
---------- ------ .. ....................
i:, Polymer A 0.085 Polymer D OA 75 75 107.7 1:3.0 110.9 1511
----------- ------------
1u PolymerA 0.050 Pol-ymer1) 0.250 104.6 107.'1 1'09.5 142
............ ......... ................ _..... .......-
............................... _................ .................---
...._.............-.._....
17 Polymer A 0.125 Polymer D 0.250 106.8 17A 107.2 147
17
WO 2011/090672 PCT/US2010/061750
[00601 Table l shows that strength could be markedly improved by addition of
the
acrylantide-containing polymer, and that drainage perfoiniance was maintained
if not
improved by adding more of the acrylamide-containing polymer, It is noted that
the dosages
typically used for dry strength polymers on the pilot paper machine are much
greater (i.e, at
least double) than what is curllparably effective on a commercial paper
machine . For
example i'0.10 % of additive is an effective, amount for o dry strength
polymer on the pilot
paper machine then. the effective amount on the commercial machine would be
about 0.05%
or less.
EXAMPLE 2
[0061] Table 2 slows the drainage performance ol'three different acrylamide-
containing polymer additives using the same wh:itewater and pulp as indicated
in the strength
testing illustrated in Table 1. The drainage performance was evaluated using
the CSF test as
indicated above. Entries 18 to 23 are shown for comparison.
Tabla. 2 t}radAtigr proprrtics of pitl1) inade able} vans' s acA-yt;noidc-
rantaiairig Iad yinars w ills Polymer
Entry Additive t. % of drypull Additive, 2, 9b of dry pulp % of drainago
100
_-___..--...... .-------.-
2 P~lymerA 0.0 ..0 - -- IiO
3 Polymer A 131
PolymerC 0.100 ICI%
-------------------------------------------------------------------------------
- ------------
Polymer C 0.230 1 t0
6 Polymer A 0.050 1' tyn.ec C 0.100 121
7 Polymer A 01.125 Polymer C 0.100 142
8 Polyr.~=r A 0.000 Pot; n e' C 0.1 7 5 137
9 Polymer A 0.050 Polymer C 0.250 121
Polyn,er A 0.125 Polymer C 0.250 1: 3
1 I Polymer D 0.100 129
---- -------- ----- --------- ------ _------- ............ .-.---..-
_.._......_.....---....----..-----------------------------__...-.._....--- --
......--------
12 Polymer D 0.150 150
13 Polymer A OA50 Poly-mmer D 0.100 137
.... ........... ............-.._...........-=---
....._.........._......._.._......._.._..-
..._......_.._..._.._.._................-._......-- -- ....
14 Polymer A 0.125 Polymer r) 0.100 137
Polymer A 1058 i'olymer D 0.175 I50
--- ----_------ __--'_-_----------------------,------------------ ..----.-
._._...--- ---- ---------.._._... __.--
16 Polymer A 0.050 Polymer D 0.250 142
17 Polymer A Ø 123 Polymer 0 0.250 1,47
is
WO 2011/090672 PCT/IIS2010/061750
1S Comparative Polymer 13 0.100 96
14 CompanaticePolytncr1. 0250 94
20 Polvmcrfr 0.050 Comparative Polymer 13 (1.100 110
21 Polymer A 0.125 Comparative Polymer E 0-100 134
22 Polymer A 0.088 Comparative Polymer It 0.175 l 13
23 Polymer A 0 050W_ Comparative Polymer Ti - 0.2 50 104
24 Polytn:r A 0.125 Comparative Polymer E 0.250 134
[0062] Table 2 demonstrates that the drainage performance of the pulp slurry
is
weaker when the anionic acrylamide-containing polymer (Comparative Polymer E)
is used
compared to the amphot.eric and cationic acrylamide-containing polymers
(Polymer C and
Polymer D). It is noted that the dosages typically used for dry strength
polymers on the pilot
paper nlaclline are. much greater (i.e. at least double) than what is
comparably effective on a
coiiunercial p>_3per machine. For example if 0.10 % of additive is an
effective amount for a
dry strength polymer on the pilot paper machine then the effective amount on
the conunercial
machine would be about 0.05% or less.
EXAMPLE 3
[0063.1 Table 3 shows results of a pilot paper machine trial using a
vulylamine-
0ntaming polyÃl'ret- an(d a cationic acrylan-nde conttainiing poli=mer-. In
this example, as in all
following examples, the p; l was (nai-ntained at 7.0, no alma was included in
the furnish, and
no sizing agents were employed.
Table 3. Results of pilot paper trtacbiuc trial at i?117.0 and in the presence
of Polymer B and cafiniile
act slatiaicle-critat.riniti!; Polymer D.
k;ntry- Additive 7 "1 Additive 2 Dry'rensiie Dry Mullen lfttrst Ring Crasit
Draiaaag.
100 100 100 100
............................. ............................ .... ..-------------
--
2 Polymer B ;.100 96.3 9i 7 100 9 f5
3 Polymer B 0.300 102.5 104.0 112A 137
- ....-...
------------- --------------- ............... ..................
4 Polyme. t) 0.100 104.5 108.6 1(17.1 104
Polymer D 0.300 105.7 1074 106.0 115
6 Polymer B 0-100 Polymer D 0.100 100.8 95.2 105.6 134
7 Polymer B 0-300 Polymer D 0.100 110.1 109.9 116-6 120
....;7- ....................._......__........_.._..
_..._...._......._......__..._-......_......._.-------- ----- --r- ------
....__-- _.._.._......_-_......._..-----
8 Polymer B 0.200 Polymer D 0.200 112.9 115.8 1 19.9 118
9 Polymer B U-100 Polynerl) 0-300 115_'1 12, C0 113,7 1 i5
--------..-------= ...._._._........
i 0 Polymer B 0.300 Polymer D 0.300 110.4 120 2 111.3 112
19
WO 2011/090672 PCTIUS2010/061750
[0064] Table 3 demonstrates that high dosages of the two polymers, excellent
strength
performance can he achieved when the two chemicals were added together
compared to their
performance alone. This method allows the paperl-naker to achieve greater
efficiency in
chemical use, and the added strength achieved when the two chemicals are.
added together
allows the papermaker to reduce the usage of the expensive vinylamine-
containing Polymer
B. It is noted that the dosages typically used for dry strength polymers on
the pilotpaper
machine are much greater (i.e. at least double) than what is comparably
effective on a
commercial paper machine. For example if 0.10 % ofadditive is an efective
amount for a
dry strength polymer on the pilot paper machine then the effective amount on
the commercial
machine would be about 0.05% or lass.
EXAMPLE 4
[0065] Table 4 shows a pilot paper machine trial employing an amiphoteric
acrylarnide-containing polymer in combination with the vinylamine-containing
polymer.
This trial was pertbrmed under conditions similar to Example 3 above. However,
in this
case, the amphoteric acrylanlidc-containing Polymer C was used, rather than
the cationic
acrylanmle-containit1iQ. Polymer El.
Table 4. Results of pilot paper machine trial with Polymer Rand amphoteric
acrytamide-contnhtitrg
Polymer C.
Entry Additive I % Additive 2 % Dry 1'ensiÃe Dry Morten Burst Ring Crush
Drsinage
-- -- - ton too 100.0 too
Polymer B 0.1010 ... .. 98.9 104.7 ;02.2 105
-------- _-------------...._..-..------
3 Polymer B 0.3300 -- 1043 123.5 103.0 143
---4 ~_. - -- PoiymerC 0.101) 100.4 03.0 `:02.4 102
-- -- PotymerC 0.300 100.9 101.9 103.9 109
................... ..................................................... ....
...._.. _._........... ...._......_.._ _......-'------'---_...----------"---- -
---------------- ..._._.... _...............
F Polymer B 0.100 Polymer C 0.100 102.1 104.1 104.1 95
............ ......................... .. -
............................................._.........--- --'-'-- - ---------
7 Polyriez' $ 0.300 Polymer C 0.100 10 11.2 i 16.4 110.'1 142
8 Polymer B 0,200 Potymcr C 0300 103.3 112.3 109.8 119
--- .__-........-- ------------- ------------------- ------------- ._...-------
-- - -..._..----._._...._.... ...---------- --- --- ----- --- ---------
9 Polym r B 0.100 Polymer C 0300 103.0 11'.'..4 105.3 105
Polymer B 0.300 Polymer C 0.300 106 i 07.9 117.1 131
[0066] I-able 4 shows that Mullen Burst and Ring Crush can be especially
enhanced
with the treatment with the two polymers in tandem versus the polymers in
isolation. The
drainage performance was affected only marginally. It is noted that the
dosages typically.
WO 2011/090672 PCT/U52010/0617.50
used for dry strength polymers on the pilot paper machine are much greater
(i.e, at least
double) than what is comparably effective on it commercial paper machine. For
example if
0.10 % of additive is an effective amount for a dry strength polymer on the
pilot paper
machine then the effective amount on the commercial machine would be about
0.05% or less.
EXAMPLE 5.
[0067;1 Table 5 shows the effect of combining aqueous dispersion polymers with
the
vinylamine-containing Polymer 13.
-'3tfle 5..4E1<titiofa of aqueous dispersion Polymers 1 and to to Folymer 13
to achieve ezthancett strength
Entry pct<iitlyc I % Additive 2 54 3arq Tensile illy- Mullen Burst icing
(:nisei Drainage
100 100 100 100
2 Polyracr B 0.100 99.0 107.6 105.4 1 17
3 Polymer 73 0 300 - 101.3 109.8 107.7 138
4 -- -- PolymerF 0.100 101.0 105.3 144.0 124
....- ._.._...
.............. -------------------------- ................- --------------
._.......................... ..... ................ .....................
.._..._...............
Polymer F 0 300 10231 102.4 110.0 135
6 Polymer B 0.1O0 Polymer F 0.100 97.5 104.6 104.1 135
7 Polymer 14 0.3011 Polymer F O.100 104.2 111.8 111.0 135
8 Polymer 13 0.2 D0 Polymer F 0:200 1(14.1 116.9 1103 140
9 Polymer 15 0.100 Polymer F 0.300 1055 i 10.4 109.1 157
--------
0 Poly mer B !'300 ?nl vmer F 0 300 108.3 19.2 114.6 125
11 - Polymer G 0.100 956 9561 102.' 123
Polymer G 0.300 99.5 10.%.3 101.2 15 i
l3 Polymer l3 0. i 00 Polymer G 0.100 101.1 :01.0 106.7 134
E4 Polymer B 1}.300 Polymer G 0.100 104.9 i 155 W~ - 108.9 142
Polymer B 0.200 Poyymm G 0. %00 103.6 114.8 110.2 145
i 6 Polynmrr B 0. 11M Polymer G 0.300 109.4 :09.7 106.7 15-; 17 Polymer B
0.300 Polymer 0 0.300 107.2 T- 150.0 111.7 139
[0068] 'fable 5 demonstrates that drainage can be maintained while achieving
significantly enhanced levels of dry strength With aqueous dispersion
polymers. Ibis noted
that the dosages typically used for dry strength polymers on the pilot paper
machine are much
greater (i.e. at least double) than what is comparably effective on a
commercial paper
machine. For example if 0.10 % of additive is an effective amount for a dry
strength
21
WO 2011/090672 PCTIUS2010/061750
polymer on the pilot paper machine then the effective amount on the commercial
machine
would be about 0.05% or less.
EXAMPLE 6
[00691 Table 6 shows the combination of vinylamine-containing Polymer 13 with
an
amphoteric acrylamid.e-containirgr polyelÃctrolyte complex Polymer H.
Table 6. Pilot paper machine trial osi)ng an amplnaterie
acrylamide.eotrt;tining polyeieetrolytc
eotaplts Polymer. 1Ã with Polymer B.
Entry 1'olynrer it added (%) Polymer 11 added (%) Dry Tensile Dry Mullen Bum
Ring Crnlx
----------- -
0 0 0.0 100 loo
! 00
2 0.0 99.9 100.8 100.6
3 0.0 0.4 101.1 104.0 1019
4 0.0 0.6 103.6 101.5
- -----------
0.1 t 97.7 97.0
..... ..... ............_.._..................__..-...._.._._..__._
6 0.1 0.2 96.6 93-8 100.9
........................ _......._.___.._....... -- -................ .... -
........ ............................. ................. --............. -'r---
.........-.._--...------"--
0.1 0.4 102A 102-9 11)0.9
8 0.1 0.6 102.0 103.5 102.3
--------------------- ------ --------- ---.-_..------ -------------- ----------
----------------------- -------------- ------------------------------- -----..-
..-...
9 D.2 0.0 96.6 97.8 101.4
0.2 0.2 101.8 107.3 101).1
................----....._....--------- --.....-.---..._-
....._._._..............-- ......................-
............................_.-_........................... ..... ...... -
11 0.2 0.4 I09 109.5 110-3
12 0.2 0.6 110.4 114.4 112.4
............... ...._ ................................ ...... .............
...................................._....._..._-----......_..----........------
---------...........'---.............
1.3 0.3 0.t) 97.5 102.4 105.3
14 0.3 02 107.4 116.0 112.6
--- -- ---------------- ------ ---
0.3 0.4 1156 122.1 115.1
I6 0.3 0.6 114.1 111.6 116.2
[0070] Table 6 shows that results comparable to amphoteric acrylami.de
containing
polymers can be achieved by using the amphoteric acrylamide containing
polyelectrolyte
complex. Excellent dry strength levels were achieved, at additive levels at
which
performance typically begins to level off. It is noted that the dosages
typically used for dry
strength polymers on the pilot paper machine are much greater (i.e. at least
double) than what
is comparably effective on a commercial paper machine. For example if 0.10 `.%
of additive
is an effective arnoultt for a dry strength polymer on the pilot paper machine
then the.
effective amount on. the commercial machine would be about 0.05% or less.
22
WO 2011/090672 PCT/US2010/061750
EXAMPLE 7
[00711 Table 7 shows dry strength and drainage testing results using a single
product
blend of Polymer K. and Polymer R. Regardless of the ratio of the two polymers
in the blend,
the additive was used at a dosage level of 0.3% versus the dr~ pulp.
Table 7. Use of a single-product blend of Polymer K and B to achieve enhanced
dry strength
Fury Polymer K. Active solids Dry Dry Mullen thug Crush Wet Drainage
Polymer E1 (%) Th,sile Hirst Tensile
I 0:4 12.7 101.9 105.5 109.6 3 73.7 I59.6
2 L:3 14.6 105.7 110.7 109.4 3479 149.0
.-..._ . ................----..-...-- ---------------------- ------------------
...-..
3 i:1 17.x. 107.9 ( 108.7 11)8.0 297.5 127.2
4 3:1 20.8 108.2 I 3 08.8 109.7 2009 109.0
[00721 Table 7 illustrates that using a single product blend of a vinylamine-
containing
polymer and a cationic acrylantide-containing polymer, imprmed dry strength
results care be
obtained in the dry tensile and dry inullen burst caÃegories while ofthring
comparable ring
crush results. The single product blend is especially useful in that it offers
the papettnaker
the ease of adding a single product to the paper machine, but the different
blend ratios make it
possible to tune the product to the paperfnaker's needs. 1 or instance, il'
lower wet streai tlt is
needed to reduce repulping energy, a single product blend can be made to meet
that need
;.chile maintaining or improving dry strength properties. Or, if the paper
machine is already
running near its maximum speed, the. amount of drainage the product provides
can be
matched to the papennaker's need without compromising dry strength.
Furthermore, th.e
single product blend can have a significantly higher active solids content
without negatively
impacting dry strength, thus reducing ecological impact due to transportation
oflow solids
content freight to the paper mill.
23
