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Patent 1306084 Summary

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(12) Patent: (11) CA 1306084
(21) Application Number: 561950
(54) English Title: PREPARATION OF FILLER COMPOSITIONS FOR PAPER
(54) French Title: PREPARATION DE MATIERES DE CHARGE POUR PAPIER
Status: Deemed expired
Bibliographic Data
(52) Canadian Patent Classification (CPC):
  • 6/194
(51) International Patent Classification (IPC):
  • C04B 14/00 (2006.01)
(72) Inventors :
  • HARVEY, RICHARD D. (United States of America)
  • KLEM, ROBERT E. (United States of America)
(73) Owners :
  • FILLER TECHNOLOGIES, LLC. (United States of America)
(71) Applicants :
(74) Agent: SMART & BIGGAR
(74) Associate agent:
(45) Issued: 1992-08-11
(22) Filed Date: 1988-03-21
Availability of licence: N/A
(25) Language of filing: English

Patent Cooperation Treaty (PCT): No

(30) Application Priority Data:
Application No. Country/Territory Date
045,221 United States of America 1987-04-29

Abstracts

English Abstract






PREPARATION OF FILLER COMPOSITIONS FOR PAPER

Abstract of the Disclosure
A process for forming a preflocculated filler for
use in making paper, which process comprises continuously
bringing together an aqueous slurry of a paper filler material
and a flocculating agent and imparting to the mixture for a
period of not more than about 2 minutes and preferably for
less than about 30 seconds, a shearing force sufficient to
provide a flocculated filler of controlled particle size and
most suitable for papermaking.


Claims

Note: Claims are shown in the official language in which they were submitted.


- 21 - 60332-1826

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process of forming a flocculated filler for
use in making paper or paperboard which consists essentially
in continuously introducing an aqueous slurry of a non-
flocculated paper filler material and an aqueous slurry of a
flocculating agent into a shear imparting device and
imparting to the mixture within said device a shearing force
sufficient to provide flocculated filler particles of a size
adapted for use in papermaking without any additional
treatment and continuously removing said flocculated filler
particles from the shear imparting device.

2. A process according to claim 1 wherein the
shearing force is imparted for a period less than 2 minutes.

3. A process according to claim 1 wherein the
shearing force is imparted for a period less than 30 seconds.

4. A process according to claim 1 wherein the
flocculating agent is a cationic starch paste.

5. A process according to claim 1 wherein the
filler material is a filler material selected from clays,
calcium carbonate and titanium dioxide.

6. A process according to claim 1 wherein the
shearing force is sufficient to provide flocculated filler
particles having an average size of from 38 to 75 microns in
greatest dimension.

7. A process according to claim 1 wherein the
paper filler material comprises more than one filler material.

- 22 - 60332-1826

8. A process according to any one of claims 1 to 7, wherein
the flocculating agent is employed in an amount of from 0.5 to 60%
by weight based on the filler material.

9. A process according to claim 8, wherein the flocculating
agent is a cationic starch paste and the filler material is
selected from the group consisting of clays, calcium carbonate and
titanium dioxide.

10. A process according to claim 9, wherein the flocculating
agent is employed in an amount of 0.5 to 3% by weight based on the
filler material; and the slurry of the flocculating agent contains
5 to 75% of the flocculating agent on a dry solids basis.


Description

Note: Descriptions are shown in the official language in which they were submitted.



16~`~34




PREPARATION OF FILLER COMPOSITIONS FOR PAPER
This invention relates to the paper and paperboard
art. In a more particular aspect~ the invention relates to
the preparation of flocculated filler compositions for use
in the manufacture of paper and paperboard.
As is well known, paper and paperboard are manu-
factured from fibers. ~ery typically, paper is manufactured
from cellulosic fibers by depositing an aqueous stock or
furnish of such fibers onto a mesh screen and removing the
water therefrom to form a paper or paperboard web consisting
of interlocked fibers. It is customary in the paper art to
incorporate in the paper furnish a mineral filler to improve
the surface of the paper for printing purposes and-to reduce
production costs. Since cellulosic fibers are relatively
expensive, production ~osts can be significantly reduced by
replacing a portion of cellulosic fibers with a less costly
mineral filler, such as a clay or calcium carbonate. The
efficient retention of filler particles in the paper sheet
during its formation is troublesome since the ~illers tend
to be lost into the water drained from the wet-formed paper
web. Non-retained filler increases the waste load and requires
an excessive filler loading in the furnish for the papermaking
process. To alleviate these problems, flocculating agents
are used with the Eiller to increase the effective particle
size of the filler thus improving its retention in the paper
web. Such flocculated filler compositions exhibit enhanced
retention with the cellulosic fibers and enable higher filler
concentrations to be utilized in the paper.

~3(~6~84


Flocculated filler compositions which are formed
prior to incorporation into the cellulosic fiber furnish are
known as preflocculated fillers. Flocculated fillers of con-
trolled particle size are very much desired in the paper-
making industry for a number of reasons, _.g., to improvefiller retention thus reducing materials cost and minimizing
save-all loads; to enable high filler retention to be achieved
while maintaining good sheet formation and to reduce the cost
of papermaking by replacing more expensive fibers with the
less costly filler materials.
Heretofore, batch operations have frequently been
employed to produce a "macrofloc" filler composition which
is then sheared to a "microfloc" of a desired smaller particle
size. These batch operations are generally conducted using
low concentrations of flocculating agents, particularly when
flocculation of the filler takes place in the presence of the
paper pulp furnish. Batch processes for preparing flocculated
filler compositions are slow, energy intensive, difficult to
scale-up and the product is inconsistent from batch-to-batch.
It is therefore a principal object of the present
invention to provide an improved and advantageous method for
producing a preflocculated filler composition for use in paper
and paperboard.
It is a further object of the invention to provide
an improved, energy-efficient process for producing on a
continuous basis a preflocculated filler composition for use
in paper and paperboard.
It is a further object of the invention to provide
a process for preparing a preflocculated filler composition
using readily available equipment which is relatively simple
and which can be easily installed at a desired location.
It is a further object of this invention to provide
a process which can be conducted at conventional filler slurry
solids minimizing the need for dilution and facilitating the

:~3~6~
-- 3 --

preparation of flocculated fillers at concentrations consistent
with common paper mill practices.
It is a further object of the invention to provide
a process for producing a preflocculated filler composition
of good uniformity and which reduces the amount of required
flocculating agent.
It is a further object of the invention to provide
a process for preparing a preflocculated filler composition
for paper in which the particle size of the filler can be
readily controlled.
It is a further object of the invention to provide
a process which is essentially instantaneous.
The present invention provides a process for forming
a preflocculated filler for use in making paper, which process
comprises continuously bringing together an aqueous slurry of
a paper filler material and a flocculating agent and imparting
to the mixture for a period of not more than about 2 minutes
and preferably for less than about 30 seconds, a shearing
force sufficient to provide a flocculated filler of controlled
particle size and most suitable for papermaking.
The filler materials which are used in accordance
with this invention are known filler materials commonly used
in the art, such as clays, e._., china clay, lithopone,
sulphate, titanium pigments, titanium dioxide, satin white,
talc, calcium carbonate, barium sulfate, gypsum, chalk
whiting and the like.
Similarly, conventional known flocculating agents
can be employed in accordance with the invention. The
flocculating agents tend to flocculate together the filler
particles and the cellulosic fibers and various materials,
generally organic polymers of high molecular weight, are
known to be useful flocculating agents. Representative of
the flocculating agents are water-soluble vinyl polymers
and gums, polyacrylamides, aluminum sulfate, mannogalactanes,
and anionic and cationic starch derivatives. The anionic
starch derivatives are generally starch derivatives which

13~
-- 4 --

contain substituent acid groups such as carboxyl, phosphate,
sulfate or sulfonate groups. Representative of such anionic
starch derivatives are from sodium chloracetate, phosphoryl
chloride, sodium trimetaphosphate, phosphoric anhydride~ acid
anhydrides, such as acetic, maleic, malonic, proprionic and
the like. Cationic starch derivatives usually contain primary,
secondary or tertiary amino groups or a quaternary a~monium
group. The starches can also be cross-linked and dextrinized,
oxidized, hydrolyzed, etherified or esterified. Cationic
starch derivatives are preferred; representative of such
cationic starch derivatives being in the range of 0.010 to
0.15 degree of substitution (D.S.) and the preferred in range
of 0.03 to 0.075 degree of substitution. (D.S. is degree of
substitution and is equivalent to the number of substituent
groups chemically bonded per anhydroglucose unit.) Represen-
tative of such cationic starches are derivatives from chloro-
hydroxypropyl trimethyl ammonium chloride, diethylaminoethyl -
hydrochloride, chlorobutenyl trimethyl ammonium chloride,
3-chloropropyl trimethyl ammonium chloride N-(3-chloro-2-
hydroxypropyl) pyridinium chloride, ethyleneimine and the like.
The amount of the flocculating agent employed can bewidely varied and can range from about 0.5 to 60%, preferably
0.5 to 3~, by weight of the filler material.
The method of this invention is more fully described
in connection with the accompanying drawings wherein:
Figure 1 is a diagrammatic flow chart illustrating
a typical embodiment of the process of this invention.
Figure 2 is an enlarged sectional view of a centrifugal
pump which can be used to impart mechanical shear in the process
of the invention.
Figure 3 is a graph illustrating the relationship of
mechanical shear force to particle size of the flocculated
filler.
Figure 4 is a plot of data of filler retention
versus filler loading.

)6~
-- 5 --

Figure 5 is a plot of sizing retention data.
Figure 6 is a plot of opacity da-ta.
Figur~s 7 and 8 are plots of paper stiffness data.
Figure 9 is a plot of paper bursting strength data.
Referring to the dxawings, Figure 1 is a flow
diagram illustrating a typical process according to this
invention. Thus, an aqueous slurry of a paper filler material,
such as calcium carbonate, is formed in the slurry tank l with
the aid of an agitator 2. Slurry concentration will be deter-
mined primarily by the filler content desired in the paper
product. Generally, the concentration of the filler slurry
in tank 1 will be in the range of 5 to 75~ dry solids and
more preferably in the range of 25-50% dry solids.
A cationic starch paste or cther suitable flocculating
lS agent (flocculent) in an aqueous slurry is stored in storage
tank 5. The filler slurry is pumped through line 12 by means
of a positive displacement pump 3 to centrifugal pump 8.
Simultaneously, the flocculating agent is pumped from tank 5
through line 13 by means of positive displacement metering
pump 6 to the centrifugal pump 8. The resultant prefloccu-
lated filler is pumped by a positive displacement pump~l0 and
discharged through line ll and is adapted for incorporation
with a paper furnish.
A pressure regulatlng valve 10, or sufficient head
on the discharge side of the pump 8, is employed to maintain
the operating pressure or back pressure greater than the
shut-off pressure as defined in the performance curve of the
centrifugal pump 8. The result is a centrifugal pump unit 8
which works as a mechanical shear mixing device, but with no
pumping capacity. Operating pressure is monitored by way of
pressure gauges 4, 7 and 9.
E'igure 2 illustrates the construction of a typical
centrifuga] pump 8, with pressure regulating valve, which,
when operat:ed with a back-pressure, imparts mechanical shear
to the fil]er-flocculent mixture. As shown in Figure 2, the
aqueous fi]ler slurry is supplied through an inlet pipe 12 at


,


, ~ .

3 3~6~
-- 6 --

a known and controlled flow rate into the eye 14 (center) of
the impeller 15. The flocculating agen-t or flocculent flows
at a known and controlled flow rate through the pipe 13 also
to the impeller eye 14. The impeller lS is rotated by a motor
driven shaft 18. The impeller lS has radial vanes 16 integrally
attached to it. The two liquids flow radially outward in the
spaces between the vanes. By the action of the impeller vanes,
mixing and back-blending of the fluids along with mechanical
shear are accomplished. The velocity of the fluid is increased
when contacted by the impeller vanes 16 and the fluid is moved
to the periphery where it is collected in the outer edges of
the impeller reaction chamber 17. Reacted material then flows
- toward and out the discharge port 19.
The constant pressure regulating valve 10 maintains
a pressure above the shut-off pressure for the centrifugal
pump 8. It then becomes an in-line device directing the rotating
shaft mechanical energy into the flow medium. The back pressure
allows the impeller reaction chamber and space between the
vanes to always remain full to avoid cavitation. The material
flow rate is determined only by the input fluid flow rate to
- the pump. By the process of this invention, a preflocculated
filler composition of desired particle size can be obtained.
For the description of the invention herein, a
typical centrifugal-type of pump was employed to impart
mechanical shear in accordance with this invention. Centri-
fugal pumps operated against a back pressure greater than the
pump shut-off pressure, are convenient and suitable devices
for use in accordance with the invention. Other means for
imparting mechanical shear as described herein include, for
example, homogenizers (such as manufactured by Tekmar Co.),
shear pumps (such as manufactured by Waukesha Foundry Co.),
emulsifiers (such as manufactured by Nettco Corp.), sonic
emulsifiers (such as manufactured by Sonic Corp.), colloid
mills (such as manufactured by Gaulin Corp.), high speed wet
mills (such as manufactured by Day Mixing), jets (such as

~3C~6~4
- 7 -

. .. . ;
manufactured by Penberthy Div., Houdaille Industries, Inc.),
high intensity mixejrs (such as manufactured by J.W. Greer,
Inc.) and the like.
The intensity of the shearing force to which the
filler-flocculent mixture is subjected according to the inven-
tion can be ~aried to control the particle size of the
flocculated filler. This affords significant advantages
since it is desired to employ flocculated fillers of particular
particle size. In general, it is desired that the flocculated
filler have an average particle size in the range of about 38
to 75 microns in greatest dimension. The objective is to
maximize filler retention while maintaining uniform distribu-
tion. The optimum particle size may vary slightly as the
application (furnish, paper grade, basis weight, machine con-
figuration, machine speed, etc.) changes; however, thisparticle size range is quite suitable for general application.
Fillers of this particle size range can be easily obtained by
regulating the shear under which the filler is produced.
Thus, for a centrifugal pump as described above
"shear force" can be calculated by multiplying the shear rate
(sec l) of the centrifugal mixer by the dwell time (sec.) of
the slurry in the mixing device. "Shear force" = Shear rate x
dwell time.
The shear rate of the centrifugal mixer is calculated
using:
Equation l.
Shear rate (sec. 1) = (n x d)(l/60)

Where: n = Speed, RPM
d = Impeller diameter
V = Volute diameter
(Volute = the chamber in which the
impeller is enclosed.)

~3~6~


The dwell time in the mixing device at various flow
rates can be calculated using:
Equation 2.
Dwell time (sec.) = Voicl Volume Of Volute
Flow Rate (mls./sec.)

Figure 3 is a plot showing the weight percentage of
flocculated filler having a particle size within the range of
38 and 75 obtained with different "shear forces". The data
plotted in Figure 3 was obtained with calcium carbona-te as the
filler and a cationic starch of a quaternary ammonium salt
having a degree of substitution of 0.0992 as the flocculent
and using as the shear imparting device a centrifugal pump
as described in Example 1. With a centrifugal pump of this
type the rate of shear depends on the diameter and speed of
the pump impeller. Since the size of the impeller remained
constant, the rate of shear was directly proportional to the
speed (R.P.M. or revolutions per minute) of the impeller.
As is readily apparent from the data plotted in
Figure 3, less flocculated filler having a particle size of
38-75 microns is obtained as the shear force increases. Thus,
as seen from Figure 3, approximately 87~ of flocculated filler
was in the 38-75 micron size range with a shear force of
3000 while only about 5~ of the filler had a particle size
in that range when using a shear force of about-9500. One
can routinely employ a suitable shear device to obtain shear
data similar to those plotted in Figure 3. From such datal
the shear force required to obtain a filler having a particle
size in the desired range can be readily determined.
The following examples illustrate the invention and
the advantages thereof. In the numbered examples, unless
otherwise indicated flocculation was achieved by use of a
shear device as described with reference to Figures 1 and 2.

9~3~6CI ~


EXAMPLE 1
An aqueous clay slurry at 20% dry solids was pumped
at a rate of 2,600 milliliters per minute to the centrifugal
mixing device described above. A ten percent cationic starch
slurry (0.036 D.S.) was simultaneously pumped -through the
mixer at a rate of 200 milliliters per minute. The cationic
starch derivative used was the ether formed when 3-chloro-
2-hydroxypropyltrimethylammonium chloride reacts with starch
to give a starch ether with a hydroxypropyltrimethylammonium
chloride side chain.
Clay and starch floccules were produced continuously,
essentially instantaneously, upon interaction. The flocculated
slurry was collected at the discharge and screened for subjec-
tive particle size analysis. All material larger than 75
microns was labeled "residue". The material smaller than 45
microns was labeled "fines". Particles between 38 and 75
microns are considered suitable for wet-end application in
paper. The initial clay slurry could be described as 100%
fines using this test method. The floccules had a predominant
particle size within the range of 38 and 75 mlcrons. Upon
screening the flocculated material, the quantity greater than
75 microns (residue~ and smaller than 38 microns (fines) was
considered negligible.

EXAMPLE 2
FoIlowing the procedure outlined in Example lt similar
runs were performed on clay ~lurries containing from 20 to 40%
dry ~olids. The starch paste having a concentration of 10%
(wt./vol.) and a degree of substltution of 0.036 was applied
at levels ranging 2.1 to 8.8 percent (dry starch) on dry
solids clay. The varying conditions for flocculation were
as follows:

~3~

-- 10 --

TABLE 1
Starch Flow Clay Clay Flow ~ Starch
Run (mls./min.) Solids (%) (mls./min.) on Clay
1 260 20 1,300 8.8
2 118 20 1,300 4.0
3 380 20 4,200 4.0
4 182 2Q 2,000 4.0
296 36 1,600 4.0
6 154 36 1,600 2.1
7 222 36 1,600 3.0
8 184 36 1,600 2.5
9 204 36 1,500 2.75
212 40 1,600 2.5

The particle size of the clay slurry w~s significantly
increased in each run based upon the test procedure described
in Example 1. This demonstrated that clay slurries could be
effectively flocculated over a wide range of filler solids,
starch additions, and flow rates. A11 the flocculated samples
upon screening were predominantly of a particle size between
; 20 45 and 75 microns.

EXAMPLE 3
This run was performed to demonstrate the ability
to continuously flocculate a calcium carbonate slurry with a
cationic starch to obtain aggregates of desirable particle
size. The calcium carbonate was a coarse ground grade, with
30% of the particles less than 2 microns in diameter. A 30~
dry solids calcium carbonate slurry was pumped at a flow rate
of 2,800 milliliters per minute to the mixing device. A five
percent paste of a 0.099 D.S. quaternary cationic starch was
pumped through the centrifugal mixer at a rate of 320 milli-
liters per minute. Analysis of the particle size dis~ribution
appears in Table 2.

~3~6~4


This run demonstrates that a calcium carbonate slurry
can be effectively flocculated using a cationic starch to con-
tinuously produce aggregates between 38 and 75 microns.
TABLE 2
Weight of Particles
~ StarchCaCO3 ~~~75 <45
Run on CaCO3Solids (~)-,75 ~45 ~38 38 Microns
1 1.5 30 6.6 50.9 9.5 33.0

Commercially available fillers which have not been
flocculated are typically much smaller ~ ., 100~ less than
38 microns and about 30% less than 1 micron.

EXAMPLE 4
A 72~ dry solids calcium carbonate slurry was floc-
culated with a 0.042 D.S. cationic starch. A 1.0~ starch
loading was employed at a total flow (starch and filler~ of
1,836 milliliters per minute. Particle size results are
summarized in Table 3~
This run demonstrates the ability to flocculate a
high solids slurry and obtain a quantity of flocccules between
38 and 75 microns.
TABLE 3
Weight of Particles
~ StarchCaCO3 ~75 c-45
Run on CaCOSolids (%) ~75 ~45 ~38~38 Microns
3-- - -
1 1.0 72 13.0 20.1 27.7 39.2




.

~3~;16~
- 12 -

EXAMPLE 5
A series of six flocculated samples were prepared
from a 72~ calcium carbonate slurry. The filler slurry flow
was held constant at 1,650 milliliters per minute. Addition
levels of 0.028 D.S. cationic starch ranged from 0.5-3.0% (dry
starch) on dry calcium carbonate. The samples were then
screened to determine the particle size distribution. Test
results are presented in Table 4.
The results show that the average particle size of
the floccules decreased as the starch loading increased.
Similar samples were prepared and tested using a
0.056 D.S. cationic starch. The same trend was observed. The
average particle size of the system decreased as the level
of starch increased. The particle size of the floccules
produced using the 0.056 D.S. cationic starch was consistently
greater than those produced with the 0.028 D.S. cationic
starch. Particle size distribution data for the 0.056 D.S.
cationic starch samples appears in Table 5.
TABLE 4
~ 0.028 D.S. Weight ~ of Particles
Run Starch on CaCO3 -~75 C75 ~38 c38 Microns
1 0.5 91.6 3.8 4.7
2 1.0 77.913.8 8.2
3 1.5 67.519.7 12.8
4 2.0 57.614.2 28.
2.5 20.247.6 32.2
6 3.0 14.S16.0 69.3




.

13~


TABLE 5
% 0.056 D.S. _ Weight % of Particles
Run Starch on CaCO3 ~ 75 ~75 ~ 38 ~ 38 Microns
1 0.5 93.4 1.6 5.1
5 2 1.0 92.1 2.2 5.7
3 1.5 87.4 3.8 8.7
4 2.0 81~6 6.4 12.0
2.5 81.0 8.5 10.5
6 3.0 71.3 16.9 11.8

The results illustrate that varying the cationicity
(D.S.) as well as the starch loading level affects the particle
size of flocculated filler.

EXAMPLE 6
A Dynamic Drainage Jar available from Paper Research
15 Materials, Inc., 770 James Street, Apt. 1206, Syracuse, New
York 13203 and Paper Chemistry Laboratory, Inc., Stoneleigh
Avenue, Carmel, New York 10512 was used to determine the
retention characteristics of the flocculated samples described
in Example 5. The fiber furnish consisted of a 75% bleached
kraft hardwood, 25~ bleached kraft softwood blend~ The fibers
were refined to 400 milliliters Canadian Standard Freeness
in a Valley beater at 1.56~ consistency. The refined stock
was then diluted to 0.5% consistency.
A 500 milliliter charge of the dilute stock was added
to the drainage chamber under 750 RPM agitation. Calcium
carbonate w~s then added at ten percent on fiber from a 2.5%
slurry. After allowing 15 seconds for mixing, a high molecular
weight, low charge density, quaternary cationic retention aid
was added at a level of 0.5 pound per ton (0.025%). The
furnish was allowed to mix for an additional 15 seconds prior
to drainage. A 30 milliliter aliquot was collected and discarded
A 100 milliliter sample was then collected and saved for calcium
carbonate retention analysis. Calcium carbonate retention was
determined using an EDTA titration procedure.

13~:16~ ~

- 14 -

The results of the experiment are tabulated in
Tables 6 and 7. The flocculated filler samples exhibited
significantly higher filler retention compared to the non-
flocculated sample.
A value referred to as "cationicity" or "cationic
demand" was calculated as the product of the starch ~D.S. -
degree of substitution) and the loading level (% on filler)
tD.S. x percent on filler). The cationicity provides a
quantitative number for the amount of positive charge in the
system contributed by the cationic starch. Generally, the
cationicity or cationic demand will be in the range of about
0.01 to 2 and preferably in the range of about 0.03 to 0.3.
In the runs conducted using the 0.028 D.S. starch,
an optimum cationicity was not achieved. A cationicity
between 0.028 and ~.085 appears optimum based on the 0.056
D.S. cationic starch.
Under similar cationicity conditions, the 0.056 D.S.
cationic starch provided superior retention. The floccules
formed with the higher dry solids starch are considered to
be more resistant to shear. In either case, the flocculated
filler provided a significant improvement in retention over
the conventional practice of utilizing a retention aid in
the furnish.
TABLE 6
~ 0.028 D.S. % CaCO3
Run Starch on CaCO3 "Cationicity" Retention
Control - 0 0 33.0
Unflocculated
CaC03
1 0.5 0.0139 44.4
2 1.0 0.0278 44~1
3 1.5 0.0417 46.7
4 2.0 0.0556 39.0
2.5 0.0695 53.2
6 3.0 0.0834 55.4

- ~3~


TABLE 7
~6 0 . 05~ D. S. % CaC03
Run Starch on CaCO3 "Cationicity" Retention
Control - 0 0 33 0
Unflocculated
1 0.5 0.02~2 58.8
2 1.0 0.0564 72.1
3 1.5 0.0846 Sl.3
4 2.0 0.112~ 56.4
2.5 0.1410 5~.7
6 3.0 0.1692 50.5

Cationicity = (Starch D.S.) (% starch on filler)
Example - (0.0564 D.S.)(1.0% starch on filler) = 0.0564
cationicity

EXAMPLE 7
Both flocculated and nonflocculated calcium carbonate
were used in the production of 65 g/m2 paper on a pilot
Fourdrinier machine. The fiber furnish was 75~ bleached kraft
hardwood, 25% bleached kraft softwood. The dry lap pulps were
disintegrated in a beater and refined at 3% in a claflin refiner
to 400 + 10 milliliters Canadian Standard Freeness.
A 50% slurry of coarse ground calcium carbonate was
used. The flocculated samples were prepared at a slurry flow
rate of 4,800 milliliters per minute. A seven percent cationic
paste (0.045 D.S.) was added at 1.5% on filler. Flocculated
and nonflocculated filler was added at 10, 20, 30 and 40 percent
on fiber. Overall calcium carbonate retention results appear
in Table 8. The flocculated filler demonstrated significantly
higher retention than the nonflocculated material. Sheets
formed with the flocculated filler exhibited good formation
quality.




,

~3~

- 16 -

TABLE 8
CaCO3 Loading CaCO3 overall CaCO
Run (% on fiber) Form Retention (%~
l 9.4 n.f. 25.26
2 10.6 f. 62.45
3 23.0 n.f. 22.98
4 22.7 f. 85.19
32.2 n.f. 22.80
6 29.1 f. 92.13
7 38.4 n.f. 29.10
8 35.4 f. 89.20
n.f. = nonflocculated
f. = flocculated

EX~MPLE 8
A flocculated calcium carbonate slurry was prepared
at 50% solids using a l.0~ addition of a 0.069 D.S. cationic
starch. The filler slurry flow rate was 4,800 milliliters per
minute. The flocculated samples were used in the production of
- paper as described in Example 7O ~onflocculated calcium
carbonate was also used for comparative purposes. Filler
loadings of 0, 20 and 40 percent on fiber were used. In selected
runs an alkyl ketene dimer internal size was added at 0.3~
on total dry solids. Sizing effectiveness was measured 24 hours
later using the Hercules Size Tester (HST). The results appear
in Table 9.
The results illustrate the ability to use flocculated
calcium carbonate in an alkaline system with an alkyl ketene
dimer and develop good sizing. The cationic starch present
in the flocculated filler systems contributed to improved
retention of the alkaline size. This is demonstrated by
superior sizing compared to the nonflocculated runs.

~3~
- 17 -

TABLE 9
First Pass
CaCO3 Loadmg CaC03 CaC03 Alkaline HST
Run (~ on fiber~ Form Retention (%) Size (%) (see.)
1 0 -- -- 0 0.2
2 0 -- 0.3681.4
3 25.7 nOf. 25.2 0 0.2
4 18.8 f. 59.9 0 0.2
25.6 n.f. 19.6 0~3 195.4
~; 10 6 24.6 f. 64.9 0.3428.3
7 35.9 n.f. 13.5 0 0.1
8 32.0 f. 53.7 0 0.4
9 39.3 n.f. 29.9 0.3 146.1
32.7 f. 47.9 0.3389.2

EXAMPLE 9
A 30% dry solids titanium dioxide slurry (partiele
; size 0.15-0.3 mierons) was floeeulated as in Example 1. The
slurry flow to the mixer was 3,340 milliliters per minute.
A 7~ eationie stareh paste (0.057 D.S.) was pumped through
the mixer at 280 milliliters per minute. This eorresponds
to a 1.5~ add-on dry solids filler. Flocculation was condueted
at a shear foree of 4814. The resulting slurry was sereened
to determine the aggregate partiele size. The results (Table
10) demonstrate the ability to continuously flocculate titanium
dioxide to a substantially larger particle size.
TABLE 13
Weight ~ of Particles
% Starch TiO2 c75 '45
RunLoading Solids ~75 45 ~38 C38 Microns
1 1.5 30~ 28.2 18.1 1.6 52.0
~'

13~)6~
- 18 -

This illustrates the ability of the process to
suitably flocculate titanus pigment in addition to the
kaolinitic clays and calcium carbonate as previously described.

EXAMPLE 10
A 30% solids slurry containing 50/50 by weight titanium
dioxide and calcium carbonate presenting a material of which
65% was less than one micron was flocculated using the con-
ditions described in Example 9. The resulting flocculated
slurry was screened to determine the particle size distribution.
The results are summarized in Table 11. Microscopic examina-
tion of the floccules produced revealed a heterogeneGus
aggregate containing starch, calcium carbonate and titanium
dioxide. The results of this experiment demonstrate that a
filler slurry containing titanium dioxide and calcium carbonate
can be continuously "co-flocculated" with a cationic starch
to produce aggregates containing both filler types.
TABLE 11
Weight % of Particles
~ Starch Slurry ~75 ~ 45
20 Runon Filler Solids~75 ~ 45 ~38 ~38 Microns
_
1 1.5 30%69.8 8.8 10.6 10.8

The ability to simultaneously floc various combina-
tions of filler additives (co-flocculation) by a process which
is continuous and essentially instantaneous offers many
benefits to a user such as a papermaker. In addition to pro-
viding heterogeneous flocs of controlled composition, the
process provides the ~lexibility to change product composition
according to needs. In addition, the process eliminates the
need for multiple systems and helps to control and minimi~e
the quantity of material in processO

~L3~36~8~

-- 19 --

EXAMPLE 11
An experiment was performed to investigate the
effect of increasing the flow through the centrifugal mixer
on the particle size of the flocculss produced. A 30%
calcium carbonate slurry was flocculated using a 0.099 D.S.
cationic starch. A 1.5~ addition of starch on filler was
maintained over flow rates ranging from 1835 to 6330 milli-
liters per minute. Particle size analysis results are
summarized in Table 12.
The results of this experiment demonstrate the
ability to control the particle size of the aggregates by
regulating the shear under which they are produced. The
shear can be regulated by: (1) changing the effective dwell
time (flow rate), (2) changing the speed of the shear unit
(RPM) and ~3) changing the size of the shear unit (d).

~E 12
,
Weiqh~ ~ of Pæticles
Slurry Flow Starch Flow c75 ~45
Run(mls./min.)(mls./min.) ~75 ,45 ,38 -~38 Microns
20 1 1,650 185 0.01.7 2.795.7
2 2,420 280 5.553.23~.0 7.3
3 2,800 320 6.650.9 9.533.0
4 3,300 370 7.255.8 2.434.7
5 4,000 450 9.768.9 4.517.0
; 25 6 4,750 535 9.667.5 0.922.0
7 5,7Q0 630 9.975.410.8 3.9

EXAMPLE 12
Both flocculated and nonflocculated calcium
carbonate were used in the production of 65 g/m2 paper on
a pilot Fourdrinier machine. The fiber furnish was 75%
bleached kraft hardwood, 25% bleached kraft softwood. The
dry lap pulps were disintegrated in a beater and refined




.
.
.,
'

~3~6~

- 20 ~ 60332-1~26

at 3~ in a claflin refiner to 400 + 10 milliliters Canadian
Standard Freeness.
A 50% slurry of coarse ground calcium carbonate
was used. The flocculated samplas were prepared at a slurry
flow rate of 4,800 milliliters per minute. A seven percent
cationic starch paste (0.045 D.S.) was added at 1.5% on
filler. Flocculated and no,nflocculated filler was added at
10, 20, 30 and 40 percent o:n fiber.
The paper waY te~ted extensively for various
properties. Significant improvement in iller retention was
achieved when using flocculated calcium carbonate, especially
considering no retention aid was present as shown from data
plotted in Figure 4. The alkaline sizing wa~ well retained
~ without a retention aid as is generally required as shown
: 15 by the data plotted in Figure 5. Moreover, opacity was im-
proved at given sheet ash when flocculated calcium carbonate
wa3 utilized as seen from the data plotted in.Figure 6.
Furthermore, ~tiffness was improved at a given sheet ash
level when flocculated filler was used as seen from the
data plotted in Figures 7 and 8. Also, the bursting strength
~ of the paper was improved at given ash levels when the:floc-
. culated fillers were used as shown by the data plotted in
Figure 9.
Those modifications and equivalents which fall
ZS within the spirit of the lnvention are to be considered a
part thereof.

.''"' , .
;
:'
-


Representative Drawing
A single figure which represents the drawing illustrating the invention.
Administrative Status

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Administrative Status

Title Date
Forecasted Issue Date 1992-08-11
(22) Filed 1988-03-21
(45) Issued 1992-08-11
Deemed Expired 2009-08-11
Correction of Expired 2012-12-05

Abandonment History

There is no abandonment history.

Payment History

Fee Type Anniversary Year Due Date Amount Paid Paid Date
Application Fee $0.00 1988-03-21
Registration of a document - section 124 $0.00 1988-07-11
Maintenance Fee - Patent - Old Act 2 1994-08-11 $100.00 1994-08-03
Maintenance Fee - Patent - Old Act 3 1995-08-11 $100.00 1995-08-01
Maintenance Fee - Patent - Old Act 4 1996-08-12 $100.00 1996-07-18
Maintenance Fee - Patent - Old Act 5 1997-08-11 $150.00 1997-07-16
Maintenance Fee - Patent - Old Act 6 1998-08-11 $350.00 1998-08-24
Maintenance Fee - Patent - Old Act 7 1999-08-11 $150.00 1999-07-16
Maintenance Fee - Patent - Old Act 8 2000-08-11 $150.00 2000-07-18
Maintenance Fee - Patent - Old Act 9 2001-08-13 $150.00 2001-07-20
Maintenance Fee - Patent - Old Act 10 2002-08-12 $200.00 2002-07-18
Maintenance Fee - Patent - Old Act 11 2003-08-11 $200.00 2003-07-17
Maintenance Fee - Patent - Old Act 12 2004-08-11 $250.00 2004-07-19
Maintenance Fee - Patent - Old Act 13 2005-08-11 $250.00 2005-07-06
Registration of a document - section 124 $100.00 2006-01-05
Maintenance Fee - Patent - Old Act 14 2006-08-11 $250.00 2006-08-04
Maintenance Fee - Patent - Old Act 15 2007-08-13 $450.00 2007-08-12
Owners on Record

Note: Records showing the ownership history in alphabetical order.

Current Owners on Record
FILLER TECHNOLOGIES, LLC.
Past Owners on Record
GRAIN PROCESSING CORPORATION
HARVEY, RICHARD D.
KLEM, ROBERT E.
Past Owners that do not appear in the "Owners on Record" listing will appear in other documentation within the application.
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Representative Drawing 2000-08-28 1 3
Description 1993-11-04 20 807
Drawings 1993-11-04 4 81
Claims 1993-11-04 2 60
Abstract 1993-11-04 1 16
Cover Page 1993-11-04 1 14
Assignment 2006-03-29 3 151
Fees 1998-08-24 1 41
Assignment 2006-01-05 7 292
Correspondence 2006-06-08 1 20
Fees 2006-08-04 1 29
Correspondence 2006-09-22 1 20
Fees 2006-08-09 1 37
Correspondence 2006-12-04 1 36
Fees 2007-08-12 1 47
Fees 2008-08-21 2 47
Fees 1996-07-18 1 73
Fees 1995-08-01 1 44
Fees 1994-08-03 1 43
Fees 1996-07-18 1 72
Fees 1995-08-01 1 44
Fees 1994-08-03 1 44