A METHOD OF IMPROVING DEWATERING EFFICIENCY, INCREASING SHEET WET
WEB STRENGTH, INCREASING SHEET WET STRENGTH AND ENHANCING FILLER
RETENTION IN PAPERMAKING
Cross-Reference to Related Applications
This application is a continuation iri part of application 12/323,976 filed on
November 26, 2008.
Statement Regarding Federally Sponsored Research or Development
Not Applicable.
Background of the Invention
This invention relates to a method of improving dewatering efficiency, increasing
sheet wet web strength, increasing sheet wet strength and enhancing filler retention in a
papermaking process. Typically in a papermaking process chemicals are added in the wet end to
assist in the dewatering of the slurry, increasing retention and improving wet or dry sheet
strength. The wet end of the papermaking process refers to the stage in the papermaking process
where the fiber is dispersed in the water in the slurry form. The fiber-water slurry then go
through drainage and dewatering process to form a wet web. The solid content after this wet
formation process is about 50%. The wet web is further dried and forms a dry sheet of paper
mat Paper mat comprises water and solids and is commonly 4 to 8% water. The solid portion of
the paper mat includes fibers (typically cellulose based fibers) and can also include filler.
Fillers are mineral particles that are added to paper mat during the papermaking
process to enhance the resulting paper's opacity and light reflecting properties. Some examples
of fillers are described in US Patent Number 7,21 1,608. Fillers include inorganic and organic
particle or pigments used to increase the opacity or brightness, reduce the porosity, or reduce the
cost of the paper or paperboard sheet Some examples of fillers include one or more of: kaolin
clay, talc, titanium dioxide, alumina trihydrate, barium sulfate, magnesium hydroxide, pigments
such as calcium carbonate, and the like.
Calcium carbonate filler comes in two forms, GCC (ground calcium carbonate)
and PCC (precipitated calcium carbonate). GCC is naturally occurring calcium carbonate rock
and PCC is synthetically produced calcium carbonate. Because it has a greater specific surface
area, PCC has greater light scattering abilities and provides better optical properties to the
resulting paper. For the same reason however, PCC filled paper mat produces paper which is
weaker than GCC filled paper in dry strength, wet strength and wet web strength.
Filler is generally much smaller than fiber, therefore, filler has much larger
specific surface area than fiber. One of the challenges people found to increase filler content in
the sheet is that high filler content decreases the efficiency of wet end chemicals, such as
dewatering aids, wet web strength aids and wet strength aids. This invention is to provide novel
filler pretreatment, so that it reduced the adsorption of wet end chemicals onto filler surface,
therefore, increased the efficiency of wet end chemicals such as dewatering aids, wet web
strength aids and wet strength aids.
Paper wet web strength is very critical for paper producers because increased
paper wet web strength would increase machine ruimability and reduce sheet breaks and machine
down time. Paper wet web strength is a function of the number and the strength of the bonds
formed between interweaved fibers of the paper mat Filler particles with greater surface area are
more likely to become engaged to those fibers and interfere with the number and strength of those
bonds. Because of its greater surface area, PCC filler interferes with those bonds more than
GCC.
Paper dewatering efficiency is also very critical for paper producers because
decreased dewatering efficiency in wet wed would increase steam demand for drying operation,
reduce machine speed and production efficiency. Dewatering aids are widely used to improve
dewatering efficiency for reducing energy consumption, increasing machine speed and production
efficiency.
Brief Summary of the Invention
At least one embodiment of the invention is directed towards a method of
papermaking having improved sheet wet strength or wet web strength or increased drainage or
filler retention through combining filler pretreatment and drainage aid or wet web strength aid or
wet strength aid . The method comprises the steps of: providing a blend of filler particles, at least
one drainage additive or one wet strength aid or one wet web strength aid, and cellulose fiber
stock; treating the filler particles with a composition of matter, combining the filler particles with
the cellulose fiber stock; and forming a paper mat by removing some of the water from the
combination. At least 10% of the filler particles are the precipitated form of calcium carbonate
(PCC) and at least 10% of the filler particles are the ground form of calcium carbonate (GCC).
The cellulose fiber stock comprises a plurality of cellulose fibers and water. The composition of
matter inhibits drainage aid or wet strength additive or wet web strength additive from adhering
to the filler particles. In at least one embodiment, the cellulose fiber stock and the filler particles
are combined to form a furnish and subsequently the filler particles are treated with the
composition of matter.
At least one embodiment of the invention is directed towards a method in which
the blend of filler particles further comprises one item selected from the list consisting of:
calcium carbonate, organic pigment, inorganic pigment, clay, talc, titanium dioxide, alumina
trihydrate, barium sulfate, magnesium hydroxide, and any combination thereof.
At least one embodiment of the invention is directed towards a method in which
the composition of matter is an AcAm/DADMAC copolymer. At least one embodiment of the
invention is directed towards a method in which the wet strength aid or wet web strength additive
or drainage aid is glyoxylated Acrylamide/DADMAC copolymer. At least one embodiment of
the invention is directed towards a method in which the wet web strength additive or wet strength
aid or drainage aid and the composition of matter carry the same charge.
At least one embodiment of the invention is- directed towards a method in which
the calcium carbonate is in one form selected from the list consisting of: dry calcium carbonate,
dispersed slurry calcium carbonate, chalk, and any combination thereof. At least a portion of the
calcium carbonate can be in a dispersed slurry calcium carbonate form, the dispersed slurry
calcium carbonate further comprising at least one item selected from: polyacrylic acid polymer
dispersants, sodium polyphosphate dispersants, Kaolin clay slurry, and any combination thereof.
The blend of filler particles can be 50% GCC and 50% PCC. The composition of matter can be a
coagulant and can be selected from the list consisting of: inorganic coagulants, organic
coagulants, condensation polymerization coagulants, and any combination thereof. The
coagulant can have a molecular weight range of between 200 and 1,000,000.
At least one embodiment of the invention is directed towards a method in which
the composition of matter is a coagulant selected from the list consisting.of: alum, sodium
aluminate, polyaluminum chlorides, aluminum chlorohydroxide, aluminum hydroxide chloride,
polyaluminum hydroxychloride, sulfated polyaluminum chlorides, polyaluminum silica sulfate,
ferric sulfate, ferric chloride, epichlorohydrin-dimethylamine (EPI-DMA), EPI-DMA ammonia
crosslinked polymers, polymers of ethylene dichloride and ammonia, condensation polymers of
multifunctional diethylenetriamine, condensation polymers of multifunctional
tetraethylenepentamine, condensation polymers of multifunctional hexamethylenediamine
condensation polymers of multifunctional ethylenedichloride, melamine polymers, formaldehyde
resin polymers, cationically charged vinyl addition polymers, and any combination thereof.
At least one embodiment of the invention is directed towards a method in which
the ratio of wet strength aid or drainage aid or wet web strength aid relative to the solid portion of
the paper mat can be 0.3 to 5 kg of additive per ton of paper mat. At least some of the GCC
particles can be treated with the composition of matter. At least one embodiment of the invention
is directed towards a method in which none of the PCC particles are treated with the composition
of matter. The filler particles can have a mass, which is up to 50% of the combined mass of the
solid portion of the paper mat. The wet strength aid or wet web strength additive or drainage
additive and the composition of matter can cany the same charge.
At least one embodiment of the invention is directed to a composition of matter
for use in a papermaking process. The composition of matter comprises: cellulose, filler
particles, a wet strength aid or wet web strength additive or drainage additive, and a coating
surrounding at least some of the filler particles. The coating is constructed and arranged to
prevent the wet strength aid or wet web strength additive or drainage aid from adhering to the
filler particles. In at least one embodiment, at least some of the filler particles are calcium
carbonate. In at least one embodiment, the filler particles are GCC, PCC, or a combination of the
two. In at least one embodiment, the filler particles comprise at least 10% PCC and 10% GCC.
Brief Description of the Drawings
A detailed description of the invention is hereafter described with specific
reference being made to the drawings in which:
FIG. 1 is a graph showing the improved wet strength of paper made according to
the invention.
FIG. 2 is a graph showing the improved wet web strength of paper made according
to the invention.
FIG. 3 is a second graph showing the improved ash content in the sheet according
to the invention.
FIG. 4 is a third graph showing the improved filler retention according to the
invention.
FIG. 5 is a graph showing the steam pressure reduction (drainage enhancement)
according to the invention.
Detailed Description of the Invention
In at least one embodiment of the invention is a method of making paper which
comprises filler. In at least one embodiment of the invention die method of papemiaking
comprises the steps of: creating a filler blend of PCC and GCC in which PCC comprises at least
10% by mass of the filler and GCC comprises at least 10% of the filler mass, pre-treating at least
some of the filler particles with a coating that decreases the adhesion between a wet web strength
additive or drainage aid or wet strength aid and the filler particles, and adding both the filler
blend and the wet web strength additive or drainage aid or wet strength aid to the paper mat.
It has been known for some time that adding wet web strength additives or
drainage aid or wet strength aid to paper mat increases the wet web strength of the resulting paper
or enhances drainage or improves machine speed and runnability or enhance sheet wet strength.
Some examples of wet strength aids, wet web strength additives and drainage aids are described
in US Patents 7,125,469, 7,615,135 and 7,641,776.
Unfortunately it is not practical to add large amounts of wet strength aids or wet
web strength additives or drainage aids to compensate for the weakness due to large amounts of
filler in paper mat. One reason is because those additives are expensive and using large amounts
of additives would result in production costs that are commercially non-viable. In addition,
adding too much additive negatively affects the process of papermaking and inhibits the
operability of various forms of papermaking equipment. Furthermore cellulose fibers can only
adsorb a limited amount of wet strength aid or wet web strength additive or drainage aid. This
imposes a limit on how much additive can be used. One reason why this is so is because wet
strength aid or wet web strength additive or drainage aid tend to neutralize the anionic fiber/ filler
charges and when these charges are neutralized further adsorption of those additives is inhibited.
Adding filler to the paper mat also reduces the effectiveness of the wet strength
aid or wet web strength additive or drainage aid. Those additives have a tendency to coat the
filler particles. The more filler particles present, the more additive coats the filler particles, and
therefore there is less wet strength aid or wet web strength additive or drainage available to bind
the cellulose fibers together. Because there is a maximum amount of wet strength aid or wet web
strength additive or drainage that can be added, more filler has always meant less effective
strength additive. This effect is more acute with PCC than GCC because PCC's higher surface
area becomes more coated with the additives than GCC.
In at least one embodiment of the invention at least some of the filler particles are
pre-treated with a composition of matter to at least partially prevent the adherence of wet strength
aid or wet web strength additive or drainage aid to the filler particles. The pre-treatment
contemplates entirely coating some or all of one or more filler particles with the composition of
matter. In the alternative, the pre-treatment contemplates applying the composition of matter to
only a portion of one or more of the filler particles, or completely coating some filler particles
and applying the composition of matter to only a portion of some other particles. In at least one
embodiment the pre-treatment is performed with at least some of the compositions of matter
described in US Patent Number 5,22 1,435 and in particular the cationic charge-biasing species
described therein. In at least one embodiment the pre-treatment is performed with a diallyl -N,Ndisubstituted
ammonium halide-acrylamide copolymer described in US Patent Number
6,592,718.
While pre-treating filler particles is known in the art, prior art methods of pretreating
filler particles are not directed towards affecting the adhesion of the wet strength aid or
wet web strength additive or drainage aid to the filler particles. In fact, many prior art pretreatments
increase the adhesion of the strength additive to the filler particles. For example, US
Patent Number 7,211,608 describes a method of pre-treating filler particles with hydrophobic
polymers. This pre-treatment however does nothing to the adhesion between the strength
additive and the filler particles and merely repels water to counterbalance an excess of water
absorbed by the strength additive. In contrast, the invention decreases the interactions between
the wet strength aid or wet web strength additive or drainage aid and the filler particles and
results in an unexpectedly huge increase in paper strength, sheet dewatering and machine
runnability.
FIG. 1 shows wet tensile strength of a given paper versus the percentage of filler
relative to the total solid portion of the paper mat used to produce the given paper. The results
clearly illustrates that sheet had very weak wet strength without addition of wet strength aid
63700 (temporary wet strength aid). Velox could significantly increase sheet wet strength. Filler
pretreatment alone did not increase sheet wet strength. However, filler pretreatment further
enhance Velox performance which resulted in higher sheet wet strength.
FIG. 2 plots wet web tensile strength of a given paper versus the percentage of
filler relative to the total solid portion of the paper mat used to produce the given paper. As
shown in FIG. 2, tire relationship between increasing filler content and decreasing paper wet web
strength is a linear relationship. Without the addition of Nalco dewatering aid (wet web strength
aid) 63700, paper sheet had very poor wet web strength. Sheet wet web strength could be
significantly improved by the using of Nalco dewatering aid 63700. Filler pretreatment alone had
negligible effect on paper wet web strength. However, filler pretreatment could further boost the
performance of Nalco dewatering aid 63700, and additional 20% wet strength improvement was
achieved by the filler pretreatment at the lower ash content. As for the higher ash content, the
performance of 63700 was boosted even higher than 20%. This is because the reduced
effectiveness of the strength additive trapped against the filler particles was released by the filler
pretreatment.
At least some of the fillers encompassed by this invention are well known and
commercially available. They include any inorganic or organic particle or pigment used to
increase the opacity or brightness, reduce the porosity, or reduce the cost of the paper or
paperboard sheet The most common fillers are calcium carbonate and clay. However, talc,
titanium dioxide, alumina trihydrate, barium sulfate, and magnesium hydroxide are also suitable
fillers. Calcium carbonate includes ground calcium carbonate (GCC) in a dry or dispersed slurry
form, chalk, precipitated calcium carbonate (PCC) of any morphology, and precipitated calcium
carbonate in a dispersed slurry form. The dispersed slurry forms of GCC or PCC are typically
produced using polyacrylic acid polymer dispersants or sodium polyphosphate dispersants. Each
of these dispersants imparts a significant anionic charge to the calcium carbonate particles.
Kaolin clay slurries also are dispersed using polyacrylic acid polymers or sodium polyphosphate.
In at least one embodiment, the treating composition of matter is any one of or
combination of the compositions of matter described in US Patent 6,592,718. In particular, any
of the AcAm/DADMAC copolymer compositions described in detail therein are suitable as the
treating composition of matter. An example of an AcAm/DADMAC copolymer composition is
product# Nalco -4690 from Nalco Company of Naperville, Illinois (hereinafter referred to as
4690).
The treating composition of matter can be a coagulant The coagulants
encompassed in this invention are well known and commercially available. They may be
inorganic or organic. Representative inorganic coagulants include alum, sodium aluminate,
polyaluminum chlorides or PACs (which are also known as aluminum chlorohydroxide,
aluminum hydroxide chloride, and polyaluminum hydroxychloride), sulfated polyaluminum
chlorides, polyaluminum silica sulfate, ferric sulfate, ferric chloride, and the like and blends
thereof.
Some organic coagulants suitable as a treating composition of matter are formed
by condensation polymerization. Examples of polymers of this type include epichlorohydrindimethylamine
(EPI-DMA), and EPI-DMA ammonia crosslinked polymers.
Additional coagulants suitable as a treating composition of matter include
polymers of ethylene dichloride and ammonia, or ethylene dichloride and dimethylamine, with or
without the addition of ammonia, condensation polymers of multifunctional amines such as
diethylenetriamine, tetraethylenepentamine, hexameihylenediamine and the like with
ethylenedichloride and polymers made by condensation reactions such as melamine
formaldehyde resins.
Additional coagulants suitable as a treating composition of matter include
cationically charged vinyl addition polymers such as polymers, copolymers, and terpolymers of
(meth)acrylamide, diallyl-N,N-disubstituted ammonium halide, dimethylaminoethyl methacrylate
and its quaternary ammonium salts, dimethylaminoethyl acrylate and its quaternary ammonium
salts, memacrylamidopropyltrimemylammoniuni chloride, diallylmethyl(betapropionamido)
ammonium chloride, (beta-methacryloyloxyemyl)trimethyl ammonium
methylsulfate, quaternized polyvinyllactam, vinylamine, and acrylamide or methacrylamide that
has been reacted to produce the Marmich or quaternary Mannich derivatives. Preferable
quaternary ammonium salts may be produced using methyl chloride, dimethyl sulfate, or benzyl
chloride. The terpolymers may include anionic monomers such as acrylic acid or 2-acrylamido 2-
methylpropane sulfonic acid as long as the overall charge on the polymer is cationic. The
molecular weights of these polymers, both vinyl addition and condensation, range from as low as
several hundred to as high as several million. Preferably, the molecular weight range should be
from about 20,000 to about 1,000,000. In at least one embodiment, the pre-treatment is
preformed by a combination of one, some, or all of any of the compositions of matter described
as suitable compositions of matter for pre-treating the filler particles.
In at least one embodiment, the wet strength aid or wet web strength additive or
drainage aids carries the same charge as the composition of matter suitable for treating the filler
particles. When the two carry the same charge, the filler additive is less likely to adsorb wet
strength aid, wet web strength additive or drainage aid on its surface. Wet strength aids, wet web
strength additives or drainage aids encompassed by the invention include any one of the
compositions of matter described in US Patent 4,605,702 and US Patent Application
2005/0161 181 Al and in particular the various glyoxylated Acrylamide/DADMAC copolymer
compositions described therein. An example of a glyoxylated Acrylamide/DADMAC copolymer
composition is product# Nalco 63700 (made by Nalco Company, Naperville, Illinois). Another
example of is amine-containing polymers including allylamine/acrylamide copolymers and
polyvinylamines; one more example is Polyamide-Polyamine-Epichlorohydrin (PAE)
In at least one embodiment, the fillers used are PCC, GCC, and/or kaolin clay. In
at least one embodiment, the fillers used are PCC, GCC, and/or kaolin clay with polyacrylic acid
polymer dispersants or their blends. The ratio of wet strength additive or wet web strength aid or
drainage additive relative to solid paper mat can be 3kg of additive per ton of paper mat.
The foregoing may be better understood by reference to the following
example, which is presented for purposes of illustration and is not intended to limit the
scope of the invention.
Example 1
1(i) Filler pre-treatment:
A blend of filler particles was obtained from a paper mill. The blend filler was a
mixture of 50% PCC and 50%100% GCC. The filler blend was diluted to 20% solid content
with tap water. 200 mL of the diluted filler blend was placed in a 500 mL glass beaker. Stirring
was conducted for at least 30 seconds prior to the addition of coagulant. The stirrer was a
EUROSTAR Digital overhead mixer with a R1342, 50 mm, four-blade propeller (both from IKA
Works, Inc., Wilmington, North Carolina). A coagulant solution was slowly added after the
initial 30 seconds of mixing under stirring with 800rpm. The coagulant solution used was 4690.
The dose of coagulant was lkg/ton based on dry filler weight. Stirring continued at 800 rpm until
all the coagulant was added. Then the stirring speed increased to 1500 rpm for one minute.
1(H) Use of filler:
Furnish was prepared by disintegrating commercial bleached hardwood dry lap.
The mixture of 50% PCC and 50% GCC was added to pulp furnish to achieve different filler
content in the sheet. 200ppm Nalco 61067 was used as retention aid. For the pretrearment
evaluation, filler mixture was pretreated using Nalco coagulant 4690 before filler was added into
the furnish. During the handsheet preparation, 3kg/ton Nalco 63700 was added to improve the
sheet wet web strength. The result was shown in Figure 2.We tried to evaluate the effect of filler
pretreatment on the press dewatering performance of 63700 by measuring sheet wet web strength.
Handsheets were pressed to a certain solid content (50%) by controlling the same pressure level
at 60 degree C, and the time required to completely break up wet sheet in water under the shear
force of 1000RPM was recorded to compare sheet wet web strength, which was expected to
indirectly reflect press dewatering. The results showed in Figure 2 indicated that sheet wet web
strength could be significantly improved by the addition of 63700. Filler pretreatment could
further boost sheet wet web strength by additional 20% at the lower ash content. As for the
higher ash content, the performance of 63700 was even higher than 20%.
Example 2
A machine trial was run in which a papermaking machine made GAB300 with
machine speed of 900m/min. A composition was provided whose cellulose fibers were 14%
MXW; 3% coated broke; 17% SOW; 12% Uncoated Broke, 44% DIP and 10% ONP. The
furnish also contained GCC. During the trial, all the wet end additives including 15/ton Nalco
press dewatering aid 63700, retention aids, sizing agents, and cationic starches were kept
constant.
1) Filler retention enhancement:
4690 was gradually increased from 0.5kg/ton to 2kg/ton based on filler. It was
found that online ash content was increased gradually with the addition of 4690 to the filler pipe
as shown in Figure 3. Obviously, 0.7 ash point increase from 15.6% to 16.3% was obtained
through filler pre-treatment. Historically, for the same grade production, recorded ash content of
DCS was about 12% without using Nalco 63700. It should be pointed out that the ash content
improvement was only contributed by filler ply. Therefore, ash content increase in filler ply was
supposed to be about 1.4% because filler ply accounted for half basis weight of the final product.
Figure 4 showed the FPAR of filler ply. It clearly illustrated that FPAR was increased from 70%
to 75%, which could explain why final ash content was significantly enhanced.
2) Steam pressure reduction:
It was also found that steam pressure of the pre-dryer was reduced through filler
treatment as shown in Figure 5. Steam pressure was gradually decreased from 2.15 to 2 bar from
10:30am to 2:00pm. Even though press pressure of the first press section and press pressure of
the second press section were reduced from 550 to 470 and 600 to 580 respectively, the steam
pressure only went back to 2.05.
During the trial, the ash content increased from around 15.6% to 16.3% about 1
hour after the filler was pretreated, then was kept at the same level for several hours. On the other '
hand, the steam pressure kept decreasing for several hours until the press load was reduced. This
seems to indicate that the steam reduction was not only from ash content increase. Moreover, the
steam demand reduction of this trial was only from filler ply since 4690 was only applied for this
ply, thus the total steam reduction caused by ash content increase alone should be less.
Therefore, the results illustrated that filler pre-treatment could enhance 63700 performance as
press dewatering agent or wet web strength aid.
A person of ordinary skill in the art will recognize that all of the previously
described methods are also applicable to paper mat comprising other non-cellulose based fibrous
materials, paper mats comprising a mixture of cellulose based and non-cellulose based fibrous
materials, and/or synthetic fibrous based materials.
Changes can be made in the composition, operation, and arrangement of the
method of the invention described herein without departing from the concept and scope of the
invention as defined in the claims. While this invention may be embodied in many different
forms, there are described in detail herein specific preferred embodiments of the invention. The
present disclosure is an exemplification of the principles of the invention and is not intended to
limit the invention to the particular embodiments illustrated. Furthermore, the invention
encompasses any possible combination of some or all of the various embodiments described
herein. All patents, patent applications, and other cited materials mentioned anywhere in this
application or in any cited patent, cited patent application, or other cited material are hereby
incorporated by reference in their entirety. Furthermore this invention contemplates
embodiments which exclude one, some, or all of the compositions, methods, components,
elements, or other portions of any cited material.
The above disclosure is intended to be illustrative and not exhaustive. This
description will suggest many variations and alternatives to one of ordinary skill in this art. All
these altematives and variations are intended to be included within the scope of the claims where
the term "comprising" means "including, but not limited to". Those familiar with the art may
recognize other equivalents to the specific embodiments described herein which equivalents are
also intended to be encompassed by the claims.
This completes the description of the preferred and alternate embodiments of the
invention. Those skilled in the art may recognize other equivalents to the specific embodiment
described herein which equivalents are intended to be encompassed by the claims attached hereto.
Claims
1. A method of papermaking comprising filler, the method comprising the steps of:
providing a blend of filler particles, at least one drainage additive or wet web strength
additive or wet strength aid, and cellulose fiber stock,
treating the filler particles with a composition of matter,
combining the filler particles with the cellulose fiber stock,
treating the combination with at least one wet strength aid or wet web strength additive or
drainage additive, and
forming a paper mat from the combination,
wherein at least 10% of the filler particles are precipitated calcium carbonate and at least
10% of the filler particles are ground calcium carbonate,
the cellulose fiber stock comprises a plurality of cellulose fibers and water, and
the composition of matter enhances the performance of the wet strength aid or wet web
strength additive or drainage additive in the paper mat.
2. The method of claim 1 in which the paper mat is formed by removing some of the water
from the combination.
3. .The method of claim 1 in which at least some of the calcium carbonate is in one form
selected from the list consisting of: undispersed calcium carbonate, dispersed slurry calcium
carbonate, chalk, and any combination thereof.
4. The method of claim 1 in which at least a portion of the calcium carbonate is in a
dispersed slurry calcium carbonate form, the dispersed slurry calcium carbonate further
comprising at least one item selected from: polyacrylic acid polymer dispersants, sodium
polyphosphate dispersants, Kaolin clay slurry, and any combination thereof.
5. The method of claim 1 in which the blend of filler particles is 50% ground calcium
carbonate and 50% precipitated calcium carbonate.
6. The method of claim 1 in which the composition of matter is a coagulant.
7. The method of claim 1 in which the composition of matter is a coagulant selected from
the list consisting of: inorganic coagulants, organic coagulants, condensation polymerization
coagulants, and any combination thereof.
8. The method of claim 1 in which the composition of matter is a coagulant having a
molecular weight range of between 200 and 1,000,000.
9. The method of claim 1 in which the composition of matter is a coagulant selected from
the list consisting of: alum, sodium aluminate, polyaluminum chlorides, aluminum
chlorohydroxide, aluminum hydroxide chloride, polyaluminum hydroxychloride, sulfated
polyaluminum chlorides, polyaluminum silica sulfate, ferric sulfate, ferric chloride,
epicUorohydrin-dimethylamine (EPI-DMA), EPI-DMA ammonia crosslinked polymers,
polymers of ethylene dichloride and ammonia, polymers of ethylene dichloride, polymers of
dimethylamine, condensation polymers of multifunctional diethylenetriamine, condensation
polymers of multifunctional tetraethylenepentamine, condensation polymers of multifunctional
hexamethylenediamine condensation polymers of multifunctional ethylenedicliloride, melamine
polymers, formaldehyde resin polymers, cationically charged vinyl addition polymers, and any
combination thereof.
10. The method of claim 1 in which the composition of matter is an AcAm/DADMAC
copolymer.
11. The method of claim 1 in which the drainage additive or wet web strength additive or wet
strength aid is one selected from the list of: glyoxylated Acrylamide/DADMAC copolymer,
poly-vinylamine, poly-vinylamide, poly-dialiylamine, and any combination thereof.
12. The method of claim 1 in which the ratio of drainage additive or wet web strength
additive or wet strength aid relative to the solid portion of the paper mat is 0.3 to 5 kg of strength
additive per ton of paper mat
13. The method of claim 1 in which at least some of the GCC particles are treated with the
composition of matter.
14. The method of claim 1 in which none of the PCC particles are treated with the
composition of matter.
15. The method of claim 1 in which the paper mat has a solid portion and the filler particles in
the paper mat comprise more than 50% of the combined mass of the solid portion of the paper
mat.
16. The method of claim 1 in which the drainage additive or wet web strength additive or wet
strength aid and the composition of matter carry the same charge.
17. The method of claim 1 in which the blend of filler particles further comprises one item
selected from the list consisting of: organic pigment, inorganic pigment, clay, talc, titanium
dioxide, alumina trihydrate, barium sulfate, magnesium hydroxide, and any combination thereof.
18. A composition of matter for use in a papermaking process, the composition of matter
comprising: cellulose, a blend of filler particles having at least 10% PCC and 10% GCC, a
drainage additive or wet web strength additive or wet strength aid, and a coating surrounding at
least some of the filler particles, the coating constructed and arranged to prevent the drainage
additive or wet web strength additive or wet strength aid from adhering to the filler particles.
19. A method of increasing the interactions between a drainage additive or wet web strength
additive or wet strength aid and cellulose fibers mixed with filler particles, the method
comprising the steps of: -
pre-treating filler particles with a composition of matter,
combining the pre-treated filler particles with cellulose fibers, and
treating the combination with at least one drainage additive or wet web strength additive
or wet strength aid,
wherein the filler particles are selected from the list consisting of precipitated calcium
carbonate, ground calcium carbonate, and any combination thereof, and
the composition of matter inhibits the drainage additive or the wet web strength additive
or wet strength aid from adhering to the filler particles.