Note: Descriptions are shown in the official language in which they were submitted.
CA 02216242 1997-09-23
] ac round of the Invention
1. Field of the Invention
The invention relates to the field of papermaking, and, in particular, to an
improved papermaking process utilizing hydrophilic dispersion polymers as
retention and
drainage aids.
2. Description of the Prior Art
In the manufacture of paper an aqueous cellulosic suspension or slurry is
formed
into a paper sheet. The cellulosic slurry is generally diluted to a
consistency (percent dry
weight of solids in the slurry) of less than 1 percent, and often below 0.5
percent, ahead
of the paper machine, while the finished sheet must have less than 6 weight
percent
water. Hence, the dewatering aspects of papermaking are extremely important to
the
efficiency and cost of the manufacture.
I ~ The least costly dewatering method is drainage, and thereafter more
expensive
methods are used, including vacuum pressing, felt blanket blotting and
pressing,
evaporation and the like, and any combination of such methods. Since drainage
is both
the first dewatering method employed and the least expensive, improvement in
the
efficiency of drainage will decrease the amount of water required to be
removed by other
methods and improve the overall efficiency of dewatering and reduce the cost
thereof.
2
CA 02216242 1997-09-23
Another aspect of papermaking that is extremely important to the efficiency
and
cost of manufacture is retention ~f furnish components on and within the fiber
mat being
formed during papermaking. A papermaking furnish contains particles that range
in size
from about the 2 to 3 millimeter size of cellulosic fibers to fillers
measuring only a few
microns. Within this range are cellulosic fines, mineral fillers (employed to
increase
opacity, brightness and other paper characteristics) and other small particles
that
generally, without the inclusion of one or more retention aids, would pass
through the
spaces (pores) between the cellulosic fibers in the fiber mat being formed.
One method of improving the retention of cellulosic fines, mineral fillers and
other furnish components on the fiber mat is the use of a coagulant/flocculant
system,
added ahead of the paper machine. In such a system there is first added to the
furnish a
coagulant, for instance a low molecular weight cationic synthetic polymer or a
cationic
starch. which coagulant generally reduces the negative surface charges present
on the
particles in the furnish, particularly cellulosic fines and mineral fillers,
and thereby
1 ~ agglomerates such particles. The coagulant is followed by the addition of
a flocculant.
The flocculant is generally a high molecular weight cationic or anionic
synthetic polymer
which bridges the particles and/or agglomerates, from one surface to another,
binding the
particles into large agglomerates. The presence of such large agglomerates in
the furnish
increases retention. The agglomerates are filtered out of the water onto the
fiber web,
'?0 where unagglomerated particles otherwise would to a great extent pass.
CA 02216242 2005-02-10
66530-631
While a flocculated agglomerate generally does not interfere with the drainage
of
' the fiber mat to the extent that would occur if the finnish were gelled or
contained an
amount of gelatinous material, when such flocs are filtered by the fiber web
the pores
thereof are reduced, thus reducing drainage e~ciency. Hence, the retention is
increased
at the expense of decreasing drainage.
Another system employed to provide an improved combination of retention and
dewatering is described in U.S. Patent Nos. 4,753,710 and 4,913,775, inventors
Langley
et al., issued respectively June 28, 1988 and April 3,1990.
In brief, such method adds to the aqueous cellulosic
papermaking suspension first a high molecular weight linear cationic polymer
before
shearing the suspension, followed by the addition of bentonite after shearing.
The
shearing generally is provided by one or more of the cleaning, mixing and
pumping
stages of the papermaking process, and the shearing breaks down the large
flocs formed
by the high rriolecular weight polymer into microflocs, and further
agglomeration then
1 ~ ensues with the addition of the bentonite clay particles.
Another system uses the combination of cationic starch followed by colloidal
silica to increase the amount of material retained on the web by charge
neutralization and
adsorption of smaller agglomerates. This system is described in U.S. Patent
No.
:1.388.150, inventors Sunden et all, issued June 14, 1983.
4
CA 02216242 2005-02-10
66530-631
U. S. Patent Nos. 5,098;520 and 5,185,062, issued to Begala,
describe methods of improving dewatering in a
PaPe~B Piss.
Summa~r of the Invention
A papermalcing process comprising foaming an aqueous cellulosic papermaking
slurry and adding a hydrophilic dispersion polymer to the slurry to increase
retention
and/or drainage is disclosed. The hydrophilic dispersion polymer comprises (a)
a cationic
monomer represented by the following.general fonmula (1):
R2
CH2=C R~
O= A g' N R4. X'
R3
wherein R, is H or CH3; each of R= and R3 is an alkyl gmup having 1 to 2
carbon atoms;
R, is H or an alkyl group of 1 to 2 carbon atoms; A is an oxygen atom or NH; B
is an
I ~ alk~ lene ~eroup of 2 to 4 carbon atoms or a hydmxypropylene group; and X'
is an anionic
counterion; and (b) a second monomer represented by (meth)acrylamide (in an
aqueous
solution of a polyvalent anionic salt), wherein the polymerization is carried
out is the
presence of either an organic high-molecular weight multivalent ration
comprising a
water-soluble polymer containing at least one monomer of formula (I) and/or
poly diallyl
5
CA 02216242 1997-09-23
dimethyl ammonium chloride (DADMAC). After addition of the polymers, the
slurry is
drained to form a sheet, and the sheet is dried.
FIG. 1 is a graph comparing turbidity reduction between three dispersion
polymers and
the standard latex retention aid.
FIG. 2 is a graph comparing drainage activity between three dispersion
polymers and the
standard latex retention aid.
FIG. 3 is a graph showing retention activity of higher intrinsic viscosity
dispersion
copolymers containing 10 and 20 mole % DMAEA~MCQ.
FIG. 4 is a graph showing drainage activity of higher intrinsic viscosity
dispersion co-
1 ~ polymers containing 10 and 20 mole % DMAEA~MCQ.
FIG. 5 is a graph comparing the retention performance of dispersion latex and
dry
polymers.
?0 FIG. 6 is a graph comparing turbidity reduction of various dispersion
polymers with
standard flocculants.
FIG. 7 is a graph comparing the drainage activity of various dispersion
polymers with
standard flocculants.
6
CA 02216242 1997-09-23
FIG. 8 is a graph comparing retention performance of dispersion polymers to
standard
latex polymer.
FIG. 9 is a graph comparing drainage performance of dispersion polymers to
standard
latex polymer.
FIG. 10 is a graph comparing retention performance of dispersion polymers
combined
with standard coagulants to dispersion polymers alone.
FIG. I I is a graph comparing draining performance of dispersion polymers
combined
with standard coagulants to dispersion polymers alone.
Description of the Preferred Embodiments
1 ~ The invention comprises a papermaking process for improving retention and
drainage comprising forming an aqueous cellulosic papermaking slurry and
adding a
hydrophilic dispersion polymer to the slurry. The slurry is then formed into a
sheet and
dried.
Preferably, the hydrophilic dispersion polymer of the invention is a copolymer
of
~U dimethylaminoethyl (meth)acrylate methyl chloride quat (DMAEA~MCQ) cationic
monomer and (meth)acrylamide (AcAm). It has been found that the polymer
described
above confers advantages for use in a papermaking process. Specifically, the
hydrophilic
dispersion polymers of the invention show improved retention activity compared
to
CA 02216242 1997-09-23
dimethylaminoethyl acrylate benzyl chloride quat
(DMAEA~BCQ)/acrylamide (AcAm) dispersion copolymer and DMAEA
methyl chloride quaternary latex of the same charge. Latex is
defined within this application as an inverse water-in-oil
emulsion polymer.
In an alternative embodiment, the DMAEA~MCQ/AcAm
hydrophilic dispersion polymers show nearly equal activity with
respect to retention and drainage as compared to the commercial
standard latex cationic polymers.
Examples 1-4 below outline processes for preparing the
copolymer at various ratios of the monomer components.
Preferably, the amount of dimethylaminoethyl acrylate methyl
chloride quaternary present in the copolymer is from about 3 mole
percent to about 20 mole percent. Further, the range of
intrinsic viscosities for the hydrophilic dispersion polymers of
the invention is preferably from about 11.9 to about 21.2 dl/g.
According to the preferred method of the invention, the
dispersion polymer is added in an amount from about 0.5 to about
5.0 pounds, preferably from about 0.8 to about 2 pounds, of
active per ton of slurry solids.
In other preferred embodiments, the method further
comprises the step of adding a coagulant before the addition of
the hydrophilic dispersion polymer, the coagulant being selected
from the group consisting of Epi/DMA and polymeric diallyl
dimethyl ammonium chloride or the step of adding a cationic
starch to the furnish in an amount of about 10 lb/ton of dry
8
66530-631
CA 02216242 1997-09-23
weight of slurry solids.
The present process is believed applicable to all
grades and types of paper products, and further applicable for
use on all types of pulps including chemical pulps, including
sulfate and sulfite pulps from both hard and soft woods and acid
pulps, thermomechanical pulps, mechanical pulps, recycle pulps
and ground wood pulps. Typically, such furnishes will have a pH
of from about 3.0 to about 9Ø
8a
66530-631
CA 02216242 1997-09-23
The following examples are presented to describe preferred embodiments and
utilities of the invention and are .not meant to limit the invention unless
otherwise stated
in the claims appended hereto.
Example 1 - Process for Synthesizing Dispersion Copolymers of Acrylamide and 3
mole %-DMAEA~MCQ.
To a two-liter resin reactor equipped with strirrer, temperature controller,
and
water cooled condenser, was added 287.59 grams of a 48.1 % solution of
acrylamide
I 0 ( I .9461 moles), 7.24 grams of an 80.6% solution of DMAEA~MCQ (0.0301
moles), 250
grams of ammonium sulfate, 225.59 grams of deionized water, 27 grams of
glycerol,
56.25 grams of a 16% solution of polyDADMAC (poly diallyl dimethyl ammonium
chloride)(IV= 1.5 dl/gm), 18 grams of a 20% solution of polyDMAEA~MCQ
( I V=?.Odl/gm), and 0.3 grams of EDTA. The mixture was heated to 48°C
and 0.50
1 ~ grams of a 4% solution of 2,2' Azobis(2 amidinopropane) dihydrochloride
was added.
The resulting solution was sparged with 1000 cc/min. of nitrogen. After 15
minutes,
polymerization began and the solution became viscous. Over the next 4 hours
the
temperature was maintained at 48°C and a solution containing 95.86
grams (0.6487
moles 1 of 48.1 % acrylamide, 12.07 grams (0.0502 moles) of an 80.6% solution
of
?0 DM1AEA~MCQ. 9 grams of glycerol and 0.1 gram of EDTA was pumped into the
reactor
9
CA 02216242 1997-09-23
using a syringe pump. To the resulting polymer dispersion was added 0.50 grams
of a
4% solution of 2,2' Azobis(2 amidinopropane) dihydrochloride. The dispersion
was then
further reacted for 2.5 hours at a temperature of 48°C to 55°C.
The resulting polymer
dispersion had a Brookfield viscosity of 5600cps. To the above dispersion was
added 10
grams of 99% acetic acid and 20 grams of sodium sulfate. The resulting
dispersion had a
Brookfieid viscosity of 1525 cps and contained 20% of a 97/3 copolymer of
acrylamide
and DMAEA~MCQ with an intrinsic viscosity of 12.1 dl/gm in 0.125 molar NaN03.
Example 2 - Process for Synthesizing Dispersion Copolymers of Acrylamide and 5
mole % DMAEA~MCQ.
To a two-liter resin reactor equipped with strirrer, temperature controller,
and
water cooled condenser, was added 281.68 grams of a 48.1 % solution of
acrylamide
( 1.9061 moles), 12.07 grams of an 80.6% solution of DMAEA~MCQ (0.05023
moles),
1 ~ ?50 grams of ammonium sulfate, 225.10 grams of deionized water, 27 grams
of glycerol,
33.75 grams of a 16% solution of polyDADMAC (IV=1.5 dl/gm), 36 grams of a 20%
solution of polyDMAEA~MCQ (IV=2.0 dl/gm), and 0.3 grams of EDTA. The mixture
was heated to 48°C and 0.50 grams of a 4% solution of 2,2' Azobis(2
amidinopropane)
dihydrochloride was added. The resulting solution was sparged with 1000
cc/min. of
nitrogen. After 15 minutes, polymerization began and the solution became
viscous. Over
CA 02216242 1997-09-23
the next 4 hours the temperature was maintained at 48°C and a solution
containing 93.89
grams (0.6354 moles)of 48.1 % acrylamide, 20.11 grams (0.08368 moles) of an
80.6%
solution of DMAEA~MCQ, 9 grams of glycerol and 0.1 grams of EDTA was pumped
into the reactor using a syringe pump. To the resulting polymer dispersion was
added
0.50 grams of a 4% solution of 2,2' Azobis(2 amidinopropane) dihydrochloride.
The
dispersicn was then further reacted for 2.5 hours at a temperature of
48°C to 55°C. The
resulting polymer dispersion had a Brookfield viscosity of 10000cps. To the
above
dispersion was added 10 grams of 99% acetic acid and 20 grams of sodium
sulfate. The
resulting dispersion had a Brookfield viscosity of 2825 cps and contained 20%
of a 95/5
copolymer of acrylamide and DMAEA~MCQ with an intrinsic viscosity of 14.1
dl/gm in
0.12 molar NaN03.
Example 3 - Process for Synthesizing Dispersion Copolymers of Acrylamide and
10
mole % DMAEA~MCQ.
l~
To a two-liter resin reactor equipped with stirrer, temperature controller,
and
water cooled condenser, was added 239.38 grams of a 48.1% solution of
acrylamide
( 1.6199 moles), 21.63 grams of an 80.6% solution of DMAEA~MCQ (0.09001
moles),
'?60 grams of ammonium sulfate, 258.01 grams of deionized water, 18 grams of
glycerol,
?0 33.7 crams of a 16% solution of polyDADMAC (IV= 1.5 dl/gm), 36 grams of a
20%
11
CA 02216242 1997-09-23
solution of polyDMAEA~MCQ (IV=2.Od1/gm), and 0.3 grams of EDTA. The mixture
was heated to 48°C and 0.50 grams of a 4% solution of 2,2' Azobis(2
amidinopropane)
dihydrochloride was added. The resulting solution was sparged with 1000
cc/min. of
nitrogen. After 15 minutes, polymerization began and the solution became
viscous. Over
the next 4 hours the temperature was maintained at 48°C and a solution
containing 79.79
grams (C.5399 moles) of 48.1% acrylamide, 36.04 grams (0.1500 moles) of an
80.6%
solution of DMAEA~MCQ, 6 grams of glycerol and 0.1 gram of EDTA was pumped
into
the reactor using a syringe pump. To the resulting polymer dispersion was
added 0.50
grams of a 4% solution of 2,2' Azobis(2 amidinopropane) dihydrochloride. The
dispersion was then further reacted for 2.5 hours at a temperature of
48°C to 55°C. The
resulting polymer dispersion had a Brookfield viscosity of 7600cps. To the
above
dispersion was added 10 grams of 99% acetic acid and 20 grams of sodium
sulfate. The
resulting dispersion had a Brookfield viscosity of 2100 cps and contained 20%
of a 90/10
copolymer of acrylamide and DMAEA~MCQ with an intrinsic viscosity of 15.5
dl/gm in
1 s 0.1'?5 molar NaN03.
Example 4 - Process for Synthesizing Dispersion Copolymers of Acrylamide and
20
mole % DMAEA~MCQ.
To a two-liter resin reactor equipped with strirrer, temperature controller,
and
water cooled condenser. was added 136.03 grams of a 48.1 % solution of
acrylamide
12
CA 02216242 1997-09-23
(0.9205 moles), 37.12 grams of an 80.6% solution of DMAEA~MCQ (0.1545 moles),
190
grams of ammonium sulfate, 50 grams of sodium sulfate, 267.99 grams of
deionized
water, 13.2 grams of glycerol, 33.75 grams of a 16% solution of polyDADMAC
(IV= 1.5
dl/gm), 45 grams of a 20% solution of polyDMAEA~MCQ (IV=2.Odl/gm), and 0.2
grams of EDTA. The mixture was heated to 48°C and 0.50 grams of a 4%
solution of
2,2' Azobis(2 amidinopropane) dihydrochloride was added. The resulting
solution was
sparged with 1000 cc/min. of nitrogen. After 15 minutes, polymerization began
and the
solution became viscous. Over the next 4 hours the temperature was maintained
at 48°C
and a solution containing 111.29 grams of 48.1 % acrylamide, 63.47 grams
(0.2641
moles) of an 80.6% solution of DMAEA~MCQ, 10.8 grams of glycerol and 0.2 grams
of
EDTA was pumped into the reactor using a syringe pump. To the resulting
polymer
dispersion was added 0.50 grams of a 4% solution of 2,2' Azobis(2
amidinopropane)
dihvdrochloride. The dispersion was then further reacted for 2.5 hours at a
temperature
of 48°C to 5~°C. The resulting polymer dispersion had a
Brookfield viscosity of 2160
1 ~ cps. To the above dispersion was added 10 grams of 99% adipic acid and 30
grams of
ammonium sulfate. The resulting dispersion had a Brookfield viscosity of 1325
cps and
contained 20% of an 80/20 copolymer of acrylamide and DMAEA~MCO with an
intrinsic viscosity 13.7 dl/gm in 0.125 molar NaN03.
The following examples utilized the test polymers and furnishes described
below.
13
CA 02216242 1997-09-23
Polymer Samples
POLYMER DESCRIPTION
Dispersions
Dispersion A 3 mole% DMAEAMCQ IV 12.1
dl/g
Dispersion B 5 mole% DMAEAMCQ IV 14.1
dl/g
Dispersion C 10 mole % DMAEAMCQ IV 14.8
dl/g
Dispersion D 10 mole% DMAEAMCQ IV 17.0
dl/g
Dispersion E 10 mole% DMAEAMCQ IV 18.2
dl/g
Dispersion F 20 mole% DMAEAMCQ IV 21.2
dl/g
Dispersion G 20 mole% DMAEAMCQ IV 19.4
dl/g
Dispersion H 10 mole% DMAEAMCQ IV 19.2
dl/g
Other Polymers
Polymer A 10 mole% DMAEAMCQ Latex IV 17.7
dl/g
Polymer B 10 mole% DMAEAMCQ Latex IV 19.1
dl/g
Polymer C 10 mole% DMAEABCQ Dispersion IV 12.9
dl/g
I'olvmer D 70/30 mole% AcAm/NaAc Latex
Polymer E 10 mole% DMAEAMCQ Dry polymer (Floerger)
Polymer F Epi-DMA solution polymer
Polymer G Poly(DADMAC) solution polymer IV 0.55
dl/g
~olvmer H Poly(DADMAC) solution polymer IV 1.9 dl/g
14
CA 02216242 1997-09-23
IV Measurement
IV measurements of pohvmer samples were carried out in 0.125 M NaN03
solution. The procedure comprises:
1. Prepare a 1% dispersion product (0.2% polymer actives) solution by
injecting 2 g of
the dispersion polymer with a syringe into the vortex of 198 g of DI water.
Continue
stirring at 800 rpm for 30 minutes.
2. Prepare a 0.045% polymer actives working solution from:
0.2% Polymer actives solution 22.5 g
Sodium acetate solution 1.0 g
0.25 Molar Sodium nitrate 50.0 g
DI water 26.5 g
3. Fill 2 ml of 0.125 Molar sodium nitrate solution into a capillary
viscometer. Measure
the time ts.
1 ~ .~. Remove the sodium nitrate solution and clean the viscometer. Fill 2 ml
of the
0.04% polymer actives solution into the viscometer. Measure the time t~.
Furnish Preparation
Three of the furnishes used for polymer activity testing were prepared from
thick
o i stock obtained from paper mills and diluted to a consistency of
approximately 0.5% with
t~ormulation water. The fourth furnish was a synthetic alkaline furnish which
comprised
70 meight % fiber and 30 weight % filler, diluted to a consistency of
approximately 0.5%
CA 02216242 1997-09-23
with formulation water. The formulation water contained 200 ppm calcium
hardness
(added as CaCl2), 152 ppm magnesium hardness (added as MgS04) and 110 ppm
bicarbonate alkalinity (added as NaHC03).
Drainage and Retention Tests
The Britt CF Dynamic Drainage jar was used for uniform mixing of polymer and
furnish; the mixing speed of the Britt jar was 500 rpm. T'he drainage tester
simulates
gravity drainage on a paper machine. The test procedures for drainage and
retention are
given below:
1. Measure a 500 ml sample of the thin stock using a graduated cylinder.
2. Add thin stock to the Britt jar.
3. Begin stirring (500 rpm) and add starch or coagulant using a syringe (when
required).
4. After 10 seconds, add polymer solution to the furnish using a syringe.
s. Stop stirring after a total time of 30 seconds. i.e. 20 seconds after
adding polymer.
1 ~ 6. Immediately transfer the treated furnish into the reservoir of the
drainage tester.
7. Remove the stopper and collect the filtrate for 5 seconds.
8. Record the weight of filtrate.
9. Measure the filtrate turbidity at 450 nm on a DR-2000 Spectrometer. The
filtrate
~~as diluted (x2) with DI water.
16
CA 02216242 1997-09-23
Drainage and turbidity data were obtained for dispersion and latex polymers
using
the test procedures described above. In these examples, a measure of retention
is given
by the percent reduction in the turbidity obtained with no polymer treatment
(blank).
Dosage curves of Drainage Improvement (%) and Turbidity Reduction (%) were
determined for polymers tested. It is well known that the retention and
drainage activities
of polymers depend on several factors including the type of furnish to be
treated. For this
reason furnishes were selected which were significantly different from each
other. The
first was a 100% recycled linerboard furnish. The second was a furnish used
for the
production of corrugated folding grade products. This furnish was a mixture of
old
corrugated cardboard (OCC), newsprint and boxboard. Thick stocks and other
additives
used for the manufacture of publication grade paper were collected to prepare
the third
furnish. The fourth furnish was prepared in the laboratory and closely
resembles the
alkaline furnish used by the paper industry for the production of fine paper.
Using the test furnishes described above, the Drainage and Retention tests
also
1 ~ described above were employed to determine drainage and retention
activities of
Dispersions A-H and Polymers A-H in Examples 5-9.
Example ~
The initial activity testings of the DMAEA~MCQ dispersion polymers were done
with 100% recycled linerboard. This furnish contained no added filler and
retention was
?0 primarily for fines from the fiber. Figure 1 shows a plot of % turbidity
reduction vs
17
CA 02216242 1997-09-23
polymer dosage for three of the hydrophilic dispersion polymers and Polymer A,
a
standard latex flocculant. The compositions of the dispersions were ( 1 )
AcAm/DMAEA~MCQ:97/3, (2) AcAm/DMAEA~MCQ:95/5, and (3)
AcAm/DMAEA~MCQ:90/I0. Dispersions A, B and C showed increased efficiency of
retention performance as compared to Polymer A. In addition, Figure 1 shows
that
turbidity reductions between 60 and 70% were achieved with the dispersion
polymers for
dosage of approximately 0.8 lbs active/t.
Figure 2 shows the drainage improvements realized by the dispersion polymers
described above. The copolymer containing 5 mole % DMAEA~MCQ showed the best
drainage behavior amongst the dispersions. However, the latex polymer, Polymer
A,
outperformed the dispersions for the entire dosage range tested. It should be
noted that
the intrinsic viscosities of the first batches of hydrophilic dispersions were
significantly
lower than Polymer A.
I ~ Example 6
The corrugated coated furnish was a mixture of OCC, newsprint and boxboard.
Unlike the recycled linerboard this furnish contained CaC03 as filler. The %
ash was
found by gravimetric measurement to be 7.3%. Preliminary activity testings
were carried
out with the lower IV ( I 1.9 - 15.7 dl/g) polymer samples and the data
indicated some
important trends in polymer performances. Both retention and drainage
performances of
18
CA 02216242 1997-09-23
the dispersion polymers improved with increasing mole% of DMAEA~MCQ. Overall,
the 10 mole% DMAEA~MCQ copolymer showed the best drainage and retention
performances among the dispersions tested.
The retention performances of the higher IV (17.0 - 21.2 dl/g) dispersion
copolymers containing 10 and 20 mole% DMAEA~MCQ are shown in Figure 3.
Dispersions D, E, F and G, containing 10 and 20 mole%. DMAEA~MCQ showed
comparable retention activities to Polymer A with corrugated coated furnish.
Figure 4 shows the drainage activities of the higher IV dispersion copolymers
containing 10 and 20 mole% DMAEA~MCQ. The results clearly demonstrate that for
the
dosage range 0 to 1.5 lbs active/t the hydrophilic dispersion polymers were
comparable to
the standard flocculant, Polymer A. As the polymer dosage was increased to 4.0
lbs
active/t. the 20 mole% DMAEA~MCQ copolymers continued to show drainage
behavior
similar to Polymer A.
Example 7
1 s The publication grade furnish was a blend of 90% (softwood, hardwood, high
ash
broke. low ash broke) and 10% (CaC03, TiO,, starch, alum). The flocculant used
at the
time of the test was Polymer D (AcAm/NaAc:70/30). Figure 5 shows the results
of Britt
jar screening of dispersion and dry polymers. On an equal actives basis at 1.5
lbs/t, the
10 mole% DMAEA~MCQ dispersion (Dispersion E) outperformed all polymers
including
Polymer C, Polymer D and Polymer E, a dry polymer available from Floerger.
19
CA 02216242 1997-09-23
Results of retention and drainage testings performed with this furnish are
given in
Figures 6 and 7. Two hydrophilic dispersions containing 10 mole% DMAEA~MCQ
were
compared with Polymer A and Polymer D. The plot of % turbidity reduction vs
dosage,
Figure 6, shows that for low dosages of flocculants significant reductions in
turbidity
~90%) were achieved for each polymer. In addition, there were no differences
in
retention: activities among the dispersion and latex polymers.
Figure 7 shows that the drainage activities of the latex and dispersion
polymers
were quite different. The latex polymer Polymer A, gave the best drainage
performance.
This was followed by the higher IV dispersion polymer. At dosages above 1.0
lb/t, the
drainage improvements for the two dispersion polymers were greater than
Polymer D.
Example 8
A synthetic alkaline furnish was prepared, containing approximately 30% CaC03
as filler and, therefore. had the highest filler loading among the furnishes
prepared.
In Example 8, cationic starch was charged to the furnish in the amount of
about 10 lb/ton
1 ~ of dry weight of slurry solids.
Figure 8 shows the dosage retention curves for two hydrophilic dispersions
containing 10 mole% and 20 mole% DMAEA~MCQ (Dispersion E, G) compared to
Polymer B and Polymer C. Polymer B (IV 19.1 dl/g) is a higher molecular weight
material than Polymer A (IV 17.7 dl/g). The results indicate that the
hydrophilic
CA 02216242 1997-09-23
dispersion polymers containing 10 and 20 mole% DMAEA~MCQ are also very
effective
retention aids for fine paper app'ication.
Drainage data for the polymers tested with the standard alkaline furnish are
given
in Figure 9. The hydrophilic dispersion containing 20 mole% DMAEA~MCQ showed
better drainage than Polymer C and the 10 mole% DMA~A~MCQ dispersion polymer.
Its drainage performance was comparable to Polymer B.
The preceding results demonstrated that the hydrophilic dispersion polymers
are
effective retention and drainage aids for a range of furnishes. The activities
of the new
dispersion polymers in the single polymer program were comparable to or
sometimes
I 0 better than the inverse emulsion polymer, Polymer A
Example 9
The effects of coagulants on the retention and drainage activities of two
DMAEA~MCQ dispersion polymers (10 and 20 mole% DMAEA~MCQ) were evaluated
in a dual polymer program and are shown in Figures 10 and 11. The corrugated
coated
1 ~ f~umish was selected for this study. Coagulants, including Polymer F,
(Epi/DMA),
1'olvmer G (polyDADMAC, IV = 0.55) and Polymer H (polyDADMAC, IV = 1.9) were
used. Figure 10 shows an increase of approximately 30% in retention
performance for
Dispersion F, the 20 mole% DMAEA~MCQ polymer with with the addition of 2.0
lbs/ton
of the hi~.h IV polyDADMAC. There were also measurable increases in retention
with
'?O f'olvmer F and Polymer G. There were no significant changes in retention
activities for
21
CA 02216242 1997-09-23
the 10 mole% DMAEA~MCQ (Dispersion D) polymer with the addition of coagulants.
The coagulants showed a less beneficial effect on the drainage activities of
the two
DMAEA.MCQ dispersion polymers (Figure 11).
Changes can be made in the composition, operation and arrangement of the
method of the present invention described herein without departing from the
concept and
scope of the invention as defined in the following claims:
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