Note: Descriptions are shown in the official language in which they were submitted.
13~980
038-158 . ~
CATIONIC CLAYS AND USES IN PAPER_AND PAINTS ~ :
~:'~" :-"
~: FIELD OF THE INVENTION . ~--
Thi~ invention relates to cationic clays and their
u~e in paper and paints, and more particularly rela~es
to cationic kaolin clays, their preparation, use as a :
filler in paper, as a pitch control agent in paper
: making, and as a coating agent in paints. , . .~-~
BACRGROUND OF THE INVEN~ION
It is well known to incorporate various ~illers in
paper and the performance of fillers varies
considerably depending on the particular filler used
and its characteristics. Such fillers, often called
pigments, include various clays, titanium dioxide,
calcium carbonate, and similar materials which provide -`~
-~: : 15 strength, opacity, brightness:and other characteristics .~-
to the paper. ~he fillers are;conventionally added to
the paper furnish during preparation of the paper and
are preferably uniformly distributed throughout the
paper sheet to optimize the ability to scatter~ light.
j~ ~ 20 The introduction of pigments conventionally often
requires the use of retention aids which causes the
primary particles to agglomerate and consequently ~ `
decreases llght:scattering ef;ficiency~
. ~ It has been suggested that the use of positively
charged particles offer the possibility of mutual
: interaction with negàtively charged fibers and so that
such fillers would remain uniformly distributed in the
~.~ 2
1330980
paper furnish. Retention aids, used for this purpose,
are usually cationic polyelectrolytes.
. In a publication by AlLnce et al Paper~ ~a Puu-
Papper och Tra, No. 3, 1983, pages 123, 124, 125, 136,
~ 5 it iB suggested that titanium dioxide particles will
; acquire a positive charge when treated with
polyethylenimine and will deposit on negatively charged
fibers suspended in water because of mutual attraction.
In a further publication by Alince et al, Tappi
Journal, .~anuary 1983, pages 92-95, it is pointed out
that the use of positively charged particl~s offers
the possibility of mutual interaction with negatively
charged fibers. In this paper, the behavior of kaolin
;~ clay pigments which have been treatsd with cationic
polyelectrolytes to give them a positive aharge is
studied. In this study, three types of kaolin clay
pLgments which have different particle sizes were used
and treated with low molecular weight polyethylenimine.
This caused the pigments to acquire a positive charge
; 20 that was pH dependent. The authors concluded from this
study that there is substantial potential advantage to
using positiveIy charged pigment particles in the wet~
end addition because of their resulting mutual
attraction to and ready deposition on negatively
charged fibers. It was pointed out that in the absence
~;~ of retention aids, the pigment particles are more
likely to remain in the water phase, not retained with
the fiber. In this case, the pigment particies are not
associated with the paper and, therefore, have no
effect on paper properties. The authors further
pointed out however that the colloidal forces between
" ~ the oppositely charged surfaces of pigment particles
~; and fibers were not strong enough to ensure an
irreversible deposition.
A fuxther study on this sub~ect was presented by
John G. Penniman, President, Paper Chemistry Consultlng
,. . . .
: ' ., ' '
.: ~-:
3 1. 3 3 0 9 8 0
Laboratory, Inc., Stoneleigh Avenue, Carmel, New York,
for The Third Internati~nal seminar On ~aper Mill
Chemistry, sOstOn, Massachusetts, August 30 - September
2, 1981. This paper concerned the suggested use of
calcium carbonate as a cationic filler in the
preparation of paper. In this paper the cationic
calcium carbonate was shown to be superior to untreated
calcium carbonate.
In a publication by Weigl et al, "Wochenblatt Fur
Papierfabrikation", Vol. 17, p. 767-773, 1987, there is
disclosure of cationic additives for coating colors.
Cationic additives such as quaternary ammonium
- .
compounds, cationic PVA, and heavily degraded, low-
molecular cationic galactomannans are mentioned.
` 15 Calcium carbonate was used as a coating pigment and is
suggested as allowing reasonable solids contents of a
cationic coating color to be achieved in contrast to
kaolin.
It is evident that the art recognizes that fillers
0 which have a cationic charge could provide improved
results when incorporated into paper during the paper
making operation. The present invention provides a
cationic clay which provides these improved advantages
heretofore recognized by the prior art, and provides
the advantages of superior attraction between the
anionic paper fibers and the pigment without the
deficiencies of the prior art cationic pigments.
In the operation of a pulp mill in the production
of paper, one of the recurring problems is control of
the pitch which is deposited during the operation.
Pitch is the sticky, resinous substance of varying
`~ composition which originates from the extractive
fraction of wood in the paper making process. Pitch
is reported to be composed of fatty acids and rosin
acids and t:heir corresponding calcium, magnesium, and
sodium salts. The pitch exists in its dispersed state
4 1 33 ~ 98
,,
until chemical changes in the paper furnish cause it to
agglomerate and deposit on screens, felts or other
paper machine surfaces. This results in holes or
break~ in the sheet and expensive down time for clean
ups. It is reported that the paper industry loses 30
million dollar3 annually because of lost production
caused by pitch problems. Though various measures have
been taken to combat these problems, by far the most
effective measure taken to the present date is the use
of talc to adsorb the pitch, thereby pre~enting
agglomeration and subsequent deposition. The talc
; pitch complex is carried out as part of the final
product so that no problem arises from its presence.
There is discussion of this problem by Gill in nPulp
Processing", Vol. 48, No. 9 tAugust, 1974) p. 104. In
addition, there is disclosed in TapPi Conference PaPer:
Alk~l~r~ yl~inq Test 1976 a publication by Albert R.
Kaiser of St. Regis Paper Company on "The Use of Talc
`~ to Control Pitch Deposition", pps. 133-134.
Use of talc as a pitch deposition control agent,
however, is expensive because of the price of talc, so
there is a need to increase efficiency of such pitch
deposition controls, while at the same time increasing
cost savings in operation of the process.
SUMMARY OF THE INVENTION
It is accordingly one ob~ect of the present
invention to provide a cationic clay which is useful as
a filler in paper, as a pitch control agent in paper
making, as a coating agent in paper, and as a coating
agent in paints.
A further ob~ect of the invention is to provide a
cationic kaolin clay which provides superior
characteristics as a filler or coating agent when
incorporated into a paper making operation.
-. - :.-:
5 1~3~80
A still further ob~ect of the inv~ntion is to
provide a cationic kaolin clay which provides improved
attraction for paper fibers including fiber fines and
further provides improved optical properties including
S brightness and printing properties to the paper and
also provides improved hiding power when incorporated
into paint as a coating agent.
An even further object of the invention is to
provide a modified kaolin cl~y for use in the control
of pitch in paper making systems.
A still further object of the invention is to
provide a modified kaolin clay which has been treated
with aluminum chlorohydrate or hydrotalcite (or
hydrotalcite analogues which are magnesium-aluminum
double hydroxides of varying [Al]/[Al] ~ [Mg] molar
ratios), which modified kaolin clay is useful in the
control of pitch and simultaneously as a filler for
paper when added to a paper making process.
; ~ Other objects and advantages of the present
~- 20 invention will become apparent as the description
thereof proceeds.
In satisfaction of the foregoing ob~ects and
advantages there is provided by this invention a
cationic kaolin clay, said cationic kaolin clay having
been produced by treatment of the clay with aluminum
chlorohydrate.
Also provided by the present invention is a method
for the treatment of paper which comprises adding the
~; cationic kaolin clay of this invention to the paper
making operation to improve fiber retention of the
cationic clay to enhance the use of the clay as a
filler in the paper and to control pitch deposition in
; the process.
The present invention also provides paper
containing as a filler or a coating agent and/or a
pitch control agent, a cationic kaolin clay, said
;
i" ~
``` 6 ~30;~
cationic kaolin clay having been produced by the ~-
reaction of kaolin clay and aluminum chlorohydrate. ~;~
The present invention also provides a paint
containing a coating agent comprising a cationic kaolin
clay, said cationic kaolin clay having been produced by
the reaction of kaolin clay and aluminum chlorohydrate.
The present invention provides a kaolin clay which
has been treated with aluminum chlorohydLate or
hydrotalcite or analogue, either in the dry form or
slurry form, said treated kaolin clay being useful for
the control of pitch deposition in a paper making
~; process.
There is also provided by the present invention a
method for the adsorption of pitch and thus the control
;~ 15 of pitch deposition in a paper making process which
comprises addition of an aluminum chlorohydrate-treated
kaolin clay or a hydrotalcite-treated kaolin clay to
the paper urnish.
BRIEF DESCRIPTION OF THE DRAWINGS -~
Reference is now made to the drawings accompanying
this application wherein:
Figure 1 is a series of three graphs showing
measurement of the cationicity of an untreated clay; ~ ;
~` Figures 2, 3, 4, 5 and 6 are a series of three
~; 25 graphs having measurements of the cationicity of a --
kaolin clay sold commercially as Hydrasperse~ by J. M.
Huber Corporation, when treated with aluminum :~
chlorohydrate at different treatment levels; and
~ Figure 7 is a graph showing a comparison of
;~; 30 different clays and their treatment levels of aluminum
chlorohydrate with respect to the amount of pitch
adsorbed in a pitch control system.
' '` ;:.~ '.'
:` ` 7 ~3309~
,
DESCRIPTION OF PR~FERRED EMBODIMENTS
A~ indicated above, this invention is concerned
with the production o a modified kaolin clay and use
of the modified kaolin clay as a filler and/or pitch
control agent in the paper making industry and a
coating agent in paints. According to this invention,
it has been unexpectedly discovered that kaolin clays
can be chemically modified to be made cationic so as to
improve various characteristics for their use as
fillers in paper a~ coating agents in paint and as
pitch control agents in paper making processes.
In conventional use of kaolin clay in paper
making, a water washed kaolin clay pigment is usually
dispersed anionically to facilitate pumping, screening,
slurry shipment, etc. At this point, the clay is not
cationic. To accomplish attraction between anionic
paper fibers and an anionic pigment such as the clay,
polymeric bridging agents known as retention aids have
been used. Other means to accomplish the attraction
which have been used in the prior art include the
treatment of one component with a highly cationic
material such as modified potato starch and the other
component with an anionic material such as polyacrylate
or sodium silicate so that when these materials are
mixed, strong attraction forces are generated. When
cationicity is desired in coatings containing pigments
such as kaolin clay, chemical flocculants such as
: . ~
quaternary ammonium salts are usually added to the
~- coating.
According to the present invention it has been
discovered that a normally anionic kaolin clay can be
made cationic prior to addition to the paper furnish so
as to result in improved attraction between a cationic
clay filler and the fibers of the paper. This means
that it may not then be necessary to add the additional
agents such as polymeric bridging agents to the
8 13309~0
mixture. Further it follows from previously cited work
with cationized pi~ments that the cationic clay of
thi~ invention will provide improved attraction between
the paper fibers and, as a result of improved paper
formation, the cationic clay and improve printing
properties of the paper. Further, when the cationic
clay of this invention is incorporated into paints and
paper coatings, the resulting optical properties of the
paint and coating films exhibit improved brightness and
hiding power.
It has been discovered according to the present
invention that the surface electrochemistry of kaolin
clay is altered by the technique of treating the clay
with aluminum chlorohydrate or a hydrotalcite.
Unexpectedly it has been discovered that with an
adequate treatment level, the cationicity is permanent
across the pH range of 3-10 where virtually all paper
making and coating is done. AS a paper filler, the
cationic clay is attracted to the anionic paper fibers
rather than being repelled, as would be expected when
using an anionic-dispersed clay. The attraction
promotes pigment retention, which lessens or eliminates
the need for retention aids, which are often high cost
items.
Additionally, when added to an aqueous system
containing anionic fibers, such as a paper fiber
slurry, the cationic clay unexpectedly shows its
greatest attraction for fiber fines thus causing co~
flocculation of pigment and fiber fines. These flocs
are more easily retained in the forming sheet than the
non-flocculated fines and are therefore better removed
from the white water system. In being retained, it
will be seen that the fiber fines promote improved
opacity and, in some instances, sheet mechanical
properties. Futhermore, with more fines retained, the
; white water system should remain cleaner, reducing or
~ 9 1~3~80
eliminating the need for drainage aids. Additionally
with less fines in the recirculating water, less
effluent would require treatment or the amount of
effluent sent for treatment would contain less solids
and usuall~ a lower sOD leve:L.
In aqueou~ coatings such as paper coating, paint,
etc,, cationic clays should act to cause a controlled
microflocculation of the coating ingredients
particularly at the substrate-coating interface thus
building structure into the coating as it begins to
dry. This could be referred to as lowering the
immobilization point of the coating. The results of
all of this would then include improving the optical
properties of the coating, including brightness and
lS hiding power.
In accordance with this invention it has been
discovered that a kaolin clay which has been modified
by treatment with aluminum chlorohydrate or a
hydrotalcite will provide normally inert kaolin clay
with qualities which enables the resulting modified
~ ~ .
kaolin clay to have cationic characteristics which make
the modified clay eminently suitable as a filler in
paper making processes and as a coating agent in
paints.
According to this invention it has also been
~; unexpectedly discovered that kaolin clays chemically
modified as described herein also improve their pitch
adsorption characteristics so that they can serve as
; ~ replacements for talc in the paper making industry and
provide increased efficiency and cost savings.
In accordance with this invention it has been
discovered that a kaolin clay which has been modified
by treatment with aluminum chlorohydrate or a
;` hydrotalcite will provide normally inert kaolin clay with ~ualities which enables the resulting modified
clay to have pitch adsorption characteristics which
lO 133~980
makes the modified clay eminently suitable as a pitch
adsorption agent in paper making processes.
The preferred reactant is a kaolin clay but
analogous substrates, either natural or synthetic,
materials such as alumina trihydrate and sodium alumino
silicates may be used in the invention.
Kaolin clays are well known materials and various
kaolin clays are mined throughout the southeast and are
identified, for example, by the re~ion from which they
are obtained, such as middle Geor~ia clays and east
Georgia clays. All kaolin clays regardless of origin
are considered to be useful within the scope of the
present invention such as English clays, China clays,
Australian clays and Brazilian clays.
The kaolin clay according to one embodiment of the
present invention is modified by treatment with
aluminum chlorohydrate. Aluminum chlorohydrate is a
known material and is also referred to as an aluminum
chlorohydroxide complex. It is of the formula
A12(OH)5cl2H2O- Aluminum chlorohydrate is sold
commercially under the name Chlorhydrol~ by Reheis
` Chemlcal. As available commercially, Chlorhydrol~ is a
clear, colorless 50~ solution and is preferably used in
~ that form in this invention. However, other physical
`; 25 forms of the aluminum chlorohydrate may also be used in treatment o the clay.
~ In the present invention the clay may be treated
;~ in dry form with the aluminum chlorohydrate or it may
be treated as a slurry. It is highly preferred that
the modified clay be prepared in slurry form, since
test re~ults have shown that the slurry treatment
process is a more simple procedure and the nature of
slurry treatment lends itself to more uniform mixtures.
Thus, this represents the preferred procedure.
It has been discovered that both fine particle
size (90-9"% finer than 2u), high surface area ~22
'~- ;'
` 11 1 3 3 0 ~ 8 0
m2/gm) clays and coarse particle size (80% ~iner than
2u or lower), low surface area clays (12 m2/gm or less)
respond equally well to treatment with aluminum ~-
chlorohydrate to produce e~fective cationic fillers.
Further, it has been found that degritted crude clays
as well as fractionated and leached beneficiated clay
~ractions can be effectively treated with aluminum
chlorohydrate to produce cationic clay products. It is
preferred that crude clay or fractionated clay slurries
contain a minimum amount of dispersant (preferably 0.1
.15% of Calgon) prior to treatment with aluminum
chlorohydrate, and that leached beneficiated clay
fractions be treated with aluminum chlorohydrate as
undispersed filter cake slurries. Further, the amount
of aluminum chlorohydrate which should be used to treat
the clay should range from about 0.5 to 1.5 wt.% and
~ more preferably from about 0.75 to 1.25 wt.~. It has
-~ been found that this minimum amount of aluminum
~ ~ chlorohydrate is effective to modify the clay in such
;;- 20 manner that the resulting modified clay excels as a
cationic clay paper filler. `~
The treatment of the kaolin clay with the aluminum
chlorohydrate is preferably carried out by forming a
clay slurry at a solids content of about 15 to 50 wt.
~; 25 preferably 30~. Thereafter, with agitation, sufficient
~;~ aluminum chlorohydrate, such as a 30 to 60 wt.%
solution, and preferably a 50 wt.% solution, is added -~
to give a total treatment level based on the clay
weight of 0.5 - 1.5%, and preferably 0.75 to 1.25%.
The treated slurry is then blunged for about 5 to 60
minutes, preferab`ly 10 to 20 minutes, and then is
either spray dried or filtered and either dried as a
cake or reslurried at 30% solids and spray dried. It
has been found that the treated slurry may be stored
:'
12
for several days prior to drying without affecting the
cationic propertie~.
The modified clay may also be formed rom a dry
` clay by treatment with aluminum chlorohydrate. In this
procedure, the aluminum chlorohydrate suspension ls
added directly to dry clay to achieve uniform and
thorough mixing and a re6ultant moistened clay. The
resultant treated clay is either oven dried or dried
using a rotary dryer/flash dxyer combination and milled
to the desired fineness of grind.
While either slurry treatment or dry treatment of
the clayB may be used, use of the sluxry process is
preferred since it is a comparatively simple process
and the nature of slurry treatment lends itself to more
uniform mixing. For these reasons, the slurry
treatment is preferred. ; ~1-
In a second embodiment of the present invention,
the clay may be treated with a double hydroxide of
magnesium and aluminum to modify the clay. One
recognized mineral form of magnesium and aluminum
double hydroxide is called hydrotalcite and is of the
g6 2( H)16 CO3 4H2O. The term hydrotalcite
will be used to refer to the recognized mineral form as
i well as hydrotalcite analogues which are magnesium~
; 25 aluminum double hydroxides of varying molar ratios.
According to this invention it is preferred that
the clay be treated with hydrotalcite-like materials
which have been produced in-situ from aluminum chloride
and magnesium chloride. In this reaction, the in situ
formation of the hydrotalcite in a clay slurry is
` achieved by the addition of desired quantities of 1.0M
AlC13 and 1.0M MgC12 to a 10 to 30 percent solids
; aqueous clay slurry, preferably 20~ solids, and
blunging to achieve good mixing. A time of about S to
15 minutes, preferably 10 minutes, is preferred.
Thereafter, sodium hydroxide, such as 2M aqueous
:
i ,
1 ~ ,
13 ~330980
sodium hydroxide solution, is slowly added to achieve a
pH in the range of 10.0 to 11.0, preferably 10.5. The
~lurry is then blunged for 5 to 15 minute~ and filtered
as on a Buchner funnel. The filter cake is then
reslurried at 20 to 40 wt.~ solids, refiltered and
dried at 120C, then hammer-milled to desired fineness
of grind. The treatment level will depend on the rat~o
of aluminum and magneqium and the percent alumina, as
well as percent magnesium oxide per 100 part~ of clay.
The following represen~s a sample calculation to
achieve a proper treatment level for in situ formation
of the hydrotalcite. -~
Sample Calculation of Treatment L~vel for in situ
Formation of Hydrotalcite
Treatment Level: Al/Al+Mg = .67 ~A12O3 = .6
%MgO - .27%
ml 1.0 M AlC13 added to 200 g clay = 26.8
ml 1.0 ~ MgC12 added to 200 g clay = 13.3
20 26.8 ml 1.O M AlC13 = 26.8 m mole AlC13 ---- 13.4 m m~le A12O3 -~
~; 13.4 mole A12O3 X 102mg A12O3/mmole = 1.367g ~-
~; 1.367 g A12O3/200 g clay = .68 g A12O3/100 g alay
13.2 ml 1.0 M MgC12 = 13.2 m mole MgC12 ---- 13.2 ml MgO
13.2 m mole MgO X 40.3 mg MgO/m mole MgO = .532 g
~; 25 .532 g MgO/200 g clay = 0.267g MgO/100 g clay
g A12O3/100 g clay X 4000 = ml 1.0 M A12C13
9 MgO/100g clay X 2000 = ml 1.0 M MgC1
: '
.
.. , ,,, ~ . . . . .. ~, . . .
. 1~ 133~0
~; It will be seQn from this calculation that the
clay is ~reated with an amount of hydrotalcite which
can range from 0.5 to 2.0 wt.%.
As pointed out above, it has been found according
to the present invention, that the cationic clay of
this invention hows unexpectedly great attraction for
fiber fines as well as other paper fibers which results
in co-flocculation of pigment and fiber fines. The
cationic clay will thus act as a self-retaining pigment
and as a flocculent in paper making operations. It
will act as a retention aid particularly for
flocculation of fines whether they are pigment or
fiber. It is further useful as a drainage aid in the
~; paper making system to aid water removal or in effluent
or white water treatment to reduce suspended solids.
1 1 It i8 also useful as a clarifying agent to attract
suspended or dissolved anionic materials in the system.
Further it can be used as a coating pigment in paints
or paper coatings to induce controlled micro-
flocculation as the coating dries and thereby enhance
coating efficiency.
In the Figures, the graphs in the upper left
1 portion illustrate the zeta potential of the cationic
; clay of the invention.
When used a~ a filler in the production of paper,
it is preferred to add the cationic clay to the paper
,~ furnish in amounts ranging from about 2 to 600 pounds
of cationic clay per ton of dry fiber. A more
preferred range of filler to be added is from about 5
to 35 pounds of cationic clay per ton of dry fiber.
When used as a paper coating agent, the cationic clay
can constitute up to 100~ of pigment used and may be
added in amounts ranging from about 2 wt. % for paper
,i board up to about 30 wt. g of the weight of the sheet
i 35 for publication paper, based on the total weight of the
::,: ~ -
,-~ 15
i33~980
sheet. When uYed in paints, the clay should be added
in an amount of about 1 to 10 wt. ~
The results of laboratory tests indicste that clay
modified with aluminum chlorohydrate or hydrotalcite
have pitch adsorption qualitiQs equal to, and in most
cases superior to, those of the more expensive talc.
Thus, an aluminum chlorohydrate kaolin combination was
found to adsorb up to 96.25% of the synthetic pitch in
test sy~tems, as compared to a 35-45% ad~orption by
talc. The treated clay performed satisfactorily in
paper filler application~. Chemical modification of
the clay ~lurry using the in situ formation of
~; hydrotalcite was alqo shown to be affective in pitch
adsorption. However, the aluminum chlorohydrate
treatment i8 more preferred in this invention since
hydrotalcita modified clays appeared to provide less
consi~tent results than the aluminum chlorohydrate
-~ modification. Al~o, the hydrotalcite modification
involve~ a multistep proces~, whlch is less economic
than the aluminum chlorohydrate.
In order to evaluate the modified clay as a pitch
control- agent, t~3t procedures were utilized to
evaluate the pitch adsorptive capacity of the agents.
This laboratory evaluation allowed direct measurement
of adsorbed pitch on the test sample~. The ad~orbed
pitch was sxtracted from the modified clays and
reactad to form a colored pltch complex whose
concentration could be mea~ured spectrophotom2trically.
The rQsults were reported as percent of total amount of
;`;~ 30 pitch adsorbed and were compared with the 4S%
` adsorptive capacity exhibited by talc. The method of
evaluation of the pitch adso~p ive capacitie~ of
mineral powder~ was a variat~ion of a procedure outlined
by D. ~. Hughes in Tappi ConfsrQnce Papers, Vol. 60,
No. 7, p. 144-146 ~1977). This involvo~ the
~ ~ `
6 1 3 3 a9 ~
mixing of a known quantity of a synthetic pitch with a - ;
dilute mineral solution. The mineral and any adsorbed
pitch i8 then separated by centrifugation. The liquid
fraction is discarded while the mineral powder is
dried. A solvent reagent is then added to the dry
mineral to extract the adsorbed pitch which may be
present. The pitch is then quantified
colorometrically. In general, the results indicated f-
that Mistron vapor talc adsorbs about 40-45~ of the
synthetic pitch, untreated kaolin clay adsorbs le~s
than 1%, and aluminum chlorohydrate-modified clay ~-~
adsorbs up to 96.25%, so that the effectiveness of the
aluminum chlorohydrate treated clay is clearly -~
apparent. This is shown in Figure 7 accompanying the
application where HSP, HP, HG and Omnifil are as
defined in the examples. ; -
It i8 a feature of the invention that the cationic
clay may be added to the paper furnish to serve both as
a pitch control agent and as a paper filler or coating
agent. The pitch control agent absorbs pitch fines -~
so they do not interfere in the paper making process
and can be carried into the final paper product without
adversely affecting the paper. Accordingly, the
cationic clay of this invention can unexpectedly serve
~;~ 25 dual purposes when incorporated into a paper furnish,
i.e., a~ a pitch control agent and filler. When used
as a pitch control agent,~the amount of cationic clay
to be added is in the range of about 3-4 wt.% based on
the total fiber in the pulp. When used as a filler, a
preferred range is from about 5-35 pounds of cationic
clay per ton of dry fiber. Accordingly, when added in
the larger amounts, the cationic clay will act as a;~
filler and inherently act as a pitch control agent if
pitch fines are present. -~;~
The following examples are presented to illustrate
the invent:ion. However the invention is not to be ;
~ :,
~ 17 133V9~0
considered to be as limited thereto as obvious
variations thereon will become apparent to those
skilled in the art. In the examples and throughout
the specification, parts are by weight unless otherwise
indicated.
In certain of the following examples, the clays to
be treated are referrecl to by the tradenames
Hydra~perse~(HSP), Hydraprint0~HP), Hydragloss~HG),
Hydrafine~HF), and Omnifil~. These terms are
trademarks of the J. M. ~uber Corporation for the
types of clays utilized. The aluminum chlorohydrate
used in the examples was a colorless 50~ aqueous
solution obtained from Reheis Chemical under the
trademark Chlorhydrol~
Exam~le 1
A crude kaolin clay from Twiggs County, Georgia,
;~ was degritted and classified to a #2 grade fraction,
bleached, coagul~ated, and filtered. The filter cake
was reblunged at 30~ solids with no dispersant added.
To ~his slurry, a 50 wt. % solution of aluminum
chlorohydrate was added at the ratio 19 pounds of
aluminum chlorohydrate per dry ton of clay under
sufficient agitation to maintain good mixing. The
resultant material was then spray dried at an inlet
temperature of 1000F and an outlet temperature of
250F. A control sample was also prepared by
completing all the steps referred to except that
~` aluminum~ chlorohydrate was nbt added. Surface
potential measurements of the products in a water
slurry were obtained across the pH range of 4-10. Zeta
~;~; potential measurements are shown in accompanying
Figure 1 for the control clay and the treated clay,
~ respectively. A comparison of the graphs in Figure 1
-~ shows the cationicity of the aluminum chlorohydrate-
treated clay as compared to the control. In the
1 ~
18 1 3 3 0 ~ 8 0 ~
graphs, the units in the y axis are mPa~M/V or -
milliPascals times amplitude divided by voltage.
Exam~le 2
A sample of paper pulp was obtained from the
; headbox of a paper machine which produces kraft medium
paper using a furnish of approximately 60% kraft pulp
and 40~ recycled corrugated containers. S~ock freeness
was determined using a Canadian Standard Freeness -
. .
Tes~er in accordance with TAPPI Method T-227, and fines
; retention was measured using a Britt Jar in accordance
with TAPPI Methods T-261 and T-269. Untreated clay and
clay treated with aluminum chlorohydrate in accordance ~
with Example 1 was added at proportions of 5, 10 and 20 ~ -
pounds per ton of dry fiber to portions of the pulp,
and freeness and fines retention were determined. This ~-.;
data is set forth in the following Table I. As will be
noted from Table I, the data shows that untreated clay
does not perform any function while the treated clay
provides fines retention and increases freeness as a
;~ re8ult of the cationic nature of the clay. ~~
' ~ ~; ' ". ' ~-
`~; '''.;' ~
~: .
` ` , '
'..''`~`' .'~.''
' '''",~
" ',',~ ,' '~
~ 19 : ~
~ 3 3 ~ 9 8 0
TABLE I ~- ~
:
: :: No
Addition 5#/T 10#/T 20#/T
FREENESS, CSF :::
Untreated Clay 330 332 335
~ Treated Clay 359 365 376 -~
'~,:' ' :.
FINES RETENTION, %
Untreated Clay 16.0 15.4 15.8
15.7
Treated Clay 29.8 36.4 44.5
Example 3 ~-~
The cationlcity of clays wa~ evaluated using a -~
clay which i8 ava~lable commercially under the
trademark Hydrasperse from the J.M. Hu~er Corporation.
Thi~ commercial grade clay was evaluated for its
cationic nature as an untreated clay, as a clay which
had been treated with five pounds of aluminum
chlorohydrate per ton/ as a clay which had been treated
with 14 pounds of aluminum chlorohydrate per ton, as a
clay which had been treated with 19 pounds of aluminum ;~`1
chlorohydrate per ton, as a clay which had been treated
with 25 pounds of aluminum chlorohydrate per ton, and
¦ ~; as a clay which had been treated with 30 pounds of
aluminum chlorohydrate per ton. The evaluation was a
measurement of surface potential of the products in a
water slurry across the pH range of 4-9. The results
are shown in Figures 2, 3, 4, 5 and 6 which are graphs
from a Mat~c ESA Zeta potential meter. The graph of
;~ 30 particular interest is the graph in the upper left of
the page which plots zeta potential along the vertical
axis and sol~tion pH along the horizontal axis. The
~: j . '.: :~
.
. :~
-
r
~ 20 13~09~0
poink where cationicity iB first obtained lies between
5 and 14 pounds per ton treatment level. At 14 pounds
per ton treatment and above, the pigment remains
cationic through the pH range of 4-9.
In ~raphs of Figures l to 6, the horizontal axis
is pH value ranging from 2-12. In each ca~e, the
vertical axis i8 the zeta potential. Note that the
units on the vertical axis change from graph to graph,
from strongly electronegative tanionic) to strongly
electropositive (cationic).
Figure l - -20 to 0, always anionic (minimum is
~7)-
Figure 2 - -8 to 0, 5#/ton treatment, always
anionic, but less in magnitude (~
lS 3-5)-
Figure 3 - 0 ~o +8, 14#~ton treatment, at a pH
of 9, system becomes cationic and
remains so through pH 4 (+6).
Figure 4 ~ 0 to +lO, l9#/ton treatment, always
cationic (+8~.
Figura 5 - 0 to +20, 25#/ton treatment, always
cationic, but stronger in magnitude
Figure 6 - 0 to +25, 30#1ton treatment, always
2S cationic, but again stronger charge
(+20 at pH 4.0).
In the following examples, the effectiveness of
pitch control ~powders was evaluated by permitting
contact between specially prepared synthetic pitch and
the pitch control powder in an aqueous system. The
adsorbed pitch was extracted from the powder and
quantified colorimetrically. It is difficult to
extract actual pitch from a problem area in a paper
mill and utilize that pitch for evaluation, so that
synthetic pitch was prepared from actual components of
: '
: . ~ .:
, . . - . ~ ~
- 21 1330~80
typlcal pitch. The experimental procedure of the
pitch preparation and evaluation involved preparing a
synthetic pitch sample by c~mbining 0.65 grams of
ground gum rosin and 0.35 grams of tall oil in an
Erlenmeyer flask. The oily mixture was then stirred
with a glass stirring rod while lM potassium
hydroxide was added dropwise until saponification
resulted. Denatured ethanol (250 ml) was added to
dissolve the ~ynthetic pitch. The resulting
concentration of the pitch preparation is 4 mg/ml. ~
The pitch adsorption test procedure comprised ~ `
slurrying 10 grams of the test clay in a Waring blender
with 400 ml distilled water for 10 minutes. 35 ml of
distilled water was first added to 50 ml glass
centrifuge tubes, followed by 1 ml of the synthetic
pitch preparatlon, and lastly 10 ml of the clay slurry.
The mixture was then stirred with a stirring rod for 15
seconds and centrifuqed for 20 minutes at 2500 rpm.
The supernatant was then poured off and discarded and
the tube containing the mineral powder and adsorbed
pitch was dried overnight at 60C.
; After drying, 10 ml of chloroform-acetic anhydride
(1:1) reagent was added to the tube and stirred to
release the adsorbed pitch from the mineral powder. ~;
The mixture was then centrifuged for 20 minutes so that
the clear reagent remained at the top of the tube. ~he
clear reagent was poured off into a small beaker and 10
drops of concentrated sulfuric acid added to effect a
color change. After exactly four minutes, the liquid
was measured on a spectrophotometer set at 400 nm and
the absorbance value was compared to absorbance values
of known quantities of extracted pitch.
Exam~le 4 ~ - ~
A fine particle size east Georgia crude clay ~-
having a particle size of about 90% finer than two
22
~` 133~80
. .
microns was slurried a8 approximately 40% solids u~ing
0.15% by weight 80dium hexametaphosphate as ~he
di8persant. The dispersed slurry was degritted on a
325 mesh screen and tha degritted slurry divided into
eight equal samples. Chlorhydrol was added to the
samples at levels ranging from 0.8 to 1.4% by weight
active Chlorhydrol~ to weight of clay. The control
~ample contained no Chlorhydrol~. Each treated sample
was mixed for three minutes under low shear using a
dispersator equipped with a cowles type blade. The
treated samples were dried on a teflon coated pan,
milled, and evaluated for pitch adsorption
character~stics using the modified Hughes method.
Results of the tests are given in Table II.~ ~ -
TABLE II
Effect of Chlorhydrol~ on Pitch Adsorption of Treated
East Georgia Degritted Clay -~
Treatment Level Percent Pitch
lbs!t Chlorhydrol~ Adsorbed
O 1 0 0
16 93.75
18 96.25
93-75 '~
22 92.50
24 90.0
~` 26 88.75
28 22.50 ~-
Mistron Vapor Talc 45.0
1~ 30 The results show maximum pitch adsorption at 0.9% -
¦;~ Chlorhydrol~ with values decreasing with higher and
~ lower Chlorhydrol~ levels. In comparison the untreated -~
¦P~ clay sample showed 10.0% pitch adsorption while a
Mi~tron Vapor talc showed 45.0~ adsorption.
~` . ''~' ': .
.~. 23
133~98~
Example 5
An undi~persed leached filter cake sample of a x~
middle Georgia clay having a particle size of about 82-
84% finer than 2 microns was obtained for treatment
:~ 5 with Chlorhydrol~. An undispersed slurry was prepared `:
from the filer cake at 30% solids by adding water to
the filter cake while mixing under moderate shear. The
slurry was divided into eight equal portions and
~: treated with Chlorhydrol~ in the same manner as Example
4.
'~ :
~ ' ' ' ' ',, ' ~ :''
';: '~' ' :
: .
133~9~0
; . TABLE III
Effect of Chlorhydrol~ on ~itch Adsorption of Treated
Hydrasperse Filter Cake
Treatmant Level ~ Consistency of Percent
lb~/t Chlorhydrol Treated Slurry Adsorbed
16 Very thick 75
18 Thick 80 ~
Slightly Thick 79
22 Slightly Fluid 35
24 Moderately Fluid 17.5
26 Fluid C10
28 Quite Fluid ~10 -~
Results of the test given in Table 111 show a
maximum adsorption of a treatment level of 18 lbs./t
`~ 15 decreasing drastically at levels above 20 lbs./t. In
comparison the untreated control had less than 10%
pitch adsorption and Mistron Vapor had 45~ pitch
~; adsorption. The results would indicate that the
coarser particle size middle Georgia clays are more
sensitive to overtreatment than the fine particle east
Georgia clays. `~
`''~ ' '.-
Example 6
A degritted east Georgia clay slurry was prepared
in the same manner described in Example 4. The slurry -~
was divided in half and each half treated with 1% ~ ~-
`~ Chlorhydrol0. One-half was mixed for about 15 minutes ~ `~
`~ ' and spray dried. The second-ha}f was filtered on
`~ bottle filterx, placed in a forced air oven and dried.
Both samples were evaluated for pitch absorption by the
modi~ied Hughes method. ~
The results ~hown in Table IV indicate that some ~-
Chlorhydrol~ was lost during the filtration but that
the resulting pitch adsorption of the treated clay was
: '':
--~ 25 1 3 3 09 8 0 :
still ~ubstantially higher than the value for talc
while lower than the value for the unfiltered sample.
~ Example 7
; An unbeneficiated Hydrasperse~ slurry prepared
from middle Georgia crude clay and having a particle
size of about 84% minus two microns was obtained and
treated in the same manner as described in Example 6.
Pitch adsorption characteristics a~ determined by the
Modified Hughes method is given in Table IV.
:
1 -: .
. .
,, . ~
: .
:~
:: : :
j ~: , :
,
; ;~
~: . . ,
! ~
1330980 ~
~ ,
~ABLE IV
Effect of Filtering Treated Slurry on Pitch Adsorption
of East Georgia Clay
Example Percent Pitch Adsorbed
Spray Dried,Piltered
As Is Oven Dried
Omnifil~ (Example 3) 82.5 73.0
Hydrasperse~ (Example 4) 66,0 47.5
Georgia
The filtered middle Georgia sample had a pitch
adsorption value significantly lower than the
unfiltered control indicating a substantial loss of
treating chemical. The pitch adsorption value was
still equivalent to talc which has a pitch adsorption
capacity ~of about 35-45%. The decrea e in pitch
adsorption due to filtration was greater for the middle
Georgia clay than for the east Georgia clay.
Example_B
A leached Hydragloss0 clay sample was obtained as
filter cake from the rotary vacuum filter and the
` filter cake reslurried at 25% solids and divided into
two samples. The~first sample was treated with 20.0
~ lbs./t of Chlorhydrol~ to produce a flowable slurry and
;~ spray dried. The~ second sample was first dispersed
with 0.15% of sodium hexametaphosphate dispersant
available commercially as Calgon Dispersantj, and
then treated with 20 lbs./t ;of Chlorhydrol~ before
spray drying. The pitch adsorption characteristics of
the two sample6 determined by the modified Hughes
- 30 method are given in Table V.
27
1330980 : ~
TABLE V
Treatment of Hydragloss~ Filter Cake with Chlorhydrol~
~; Calgon Pitch
Dispersant Chlorhydrol~ Adsorption
5SamPle ~ _% SlurrY %
- 1.0 fluid 82.5
2 .15% 1.0 thick 69.0
The results show that good pitch adsorption
characteri~tics can be obtained by treating reslurried
filter cake with sufficient Chlorhydrol~ to obtain a
good slurry flow or by treating dispersed filter cake ~-
sluxry with Chlorhydrol0.
Exam~le 9 -~
A crude east Georgia Clay wa~ obtained and ~ L
dispexsed at about 40% solids using sodium hexameta~
phosphate as the dispersant. Dispersant levels of 2,
`~ 4, 6 and 8 lbs./t of clay were employed. The dispersed
slurries were degritted and ~olids reduced to 25%.
Each slurry was then treated with 20 lbs./t of active
Chlorhydrol~ and pan dried. Pitch adsorption for the
four samples, as determined by the modified Hughes
~- method is given in Table VI.
. ,
TABLE VI ~ -
Effect of Dispersant on Pitch Adsorption of ; ~;
Degritted East Georgia Clay
Dispersant Level, Slurry Pitch Adsorption,
Cal~on Consistenc~ %
`~ ~ .10 Moderately Fluid 82.5
.20 Moderately Thick 85.0
.30 Thick 82.5
~; .40 Very Thick 75.0
,:~
-; -
- \ :
133~980
Very little difference in pitch absorption was
observed for the four samples, however, the lawer level
of di~persant would be preferred. A difference in the
consistency of the treated slurries was obser~ed with
the sample containing the least amount o~ dispersant
being th~ most fluid and the sample containing the
greatest amount of dispersant being the most viscous.
,- ~
;~ Exam~le 10 ;
A coarsQ centrifuge underflow fraction from a ~`
middle Georgia clay having a particle size of 30% minus
~; ~ 2 microns and a surface area of 8.5 m2/gm was treated
with from 8 to 21 lbs. Chlorhydrol~ per ton o~ clay and
the treated slurries pan dried. The pitch adsorption ~ -
characteristics of the treated clays are given in Table ~ -
~ 15 VII.
;~ Maximum pitch adsorption was obtained with 15
; ~ lbs./t of Chlorhydrol~, indicating that a suitable
pitch adsorption product could be produced from a
coarse underflow fraction.
;~ 20 Example 11
Leached Hydraprint~ filter cake, which is a
~ delaminated clay produced from middle Georgia clays,
; ~ was treated with Chlorhydrol~ at 30~ solids and spray
dried. The Hydraprint~ fraction had a surface area of
11.3 m2/gm and a particle size of 72% minus 2 microns.
Results of the test are given in Table VII.
~ ~ i
.:~ ~ , '
"'''~
29
TABLE VII
Pitch Adsorption of Treated Underflow Clay
Clay Chlorhydrol~, Pitch Adsorbed, ~:
~ lb~./t %
Centrifuge 8 9.0
~: Underflow 12 17.5
:~ Underflow 15 70.0 :~
Underflow 18 67.5 ~:
Underflow 21 10.0
Hydraprint~ 15 62.5
:~ Hydraprint~ 18 74.0 - .
: Hydraprint 21 75.0
The results of the test indicated gaod pitch :~:
adsorption characteristics at a treatment level of 18 -~
lS to 21 lbs./t. ~ :~
Example 12 ~ii#
A degritted east Georgia clay slurry was treated
`~: with Chlorhydrol~ at levels ranging from 5 to 18 :
lbs./ton of clay. The treated slurries were pan dried .
and evaluated for pitch adsorption characteristics ~:
~; using the modified Hughes method. Results of the testsi~
are given in Table VIII. :
~:~ TABLE VIII
~: 25 Pitch Adsorption of East Georgia Clay Tr&ated
With Different Levels o~f Chlorhydrol .
Chlorhydrol , Pitch Adsorption,
lbs./t
~: 30 10
12 74
78 ~ .
18
`:~ 20 82.5
:: 35 The results indicate that good pitch adsorption
~ '~ .': . ,'
~33~g~0
characteristics can be obtained by treating degritted~;~
east Georgia clays with as little as 12 lbs./t of
Chlorhydrol~ but that maximum adsorption is obtained
wlth at lea~t 20 lbs.ton.
ExamPle 13 .
An undisper~ed middle Georgia Hydrasperse~
fraction wa~ treated with 18 lbs./t of Chlorhydrol~ and
pan dried in an aluminum electric frying pan as well as
a teflon coated pan. The slurries were dried to about
5% moisture and then to dryness in an oven. The sample
dried in the uncoated pan had a pitch adsorption value
of 69% while the sample dried in the teflon coated pan
had a value of 80%, indicating that the Chlorhydrol~
`~ interacted with the aluminum during drying.
. :; ::
ExamPle 14
A f$ne particle, high surface area airfloated clay
~` from South Carolina was treated neat with Chlorhydrol~
using a Vee Blendor. The treated clay products
containing 0.75, 1.0 and 1.5% Chlorhydrol~ were oven
dried, milled and evaluated for their pitch adsorption
capabilities using the modified Hughes method. The
samples treated with .75, 1.0 and 1.5% Chlorhydrol~
gave pitch adsorption values of 85, 24 and 20%
respectively. The sample tested with 0.75%
Chlorhydrol~ had a pitch~ adsorption capacity of about
twice that of talc.
Example 15
The in situ formation o~ hydrotalcite in clay
~`~ slurries was most successful for pitch control when
utilizing undispersed starting cIay~. In thi~ example
a study was conducted of hydrotalcite formation in a
~ , .. .
~. . ~ . , ."
: 31 133~0
predi~per~ed Hydrafine~ ~lurry prepared from production :
spray dried clay, as well as both dispersed and
undisper~ed slurries prepared in the laboratory from
undried Hydrafine~ filter cake. While production
S Hydrafine~ and the dispersed Hydraine~ filter cake :~
produced similar results of 28.75 and 30% adsorption, ~: ;
respectively, the undispersed Hydrafine~ produced 42~ - ;
adsorption levels. These results are shown in the~:.
following Table IX. ~
,~
: ,.'. ., .: ,"
~ .... ~
, -:
,~., ".,~,. ....
1 3 3 0 9 8 0
,
TABLE IX
Hydrotalcite
% % % Pitch -~
Clay Al/Al+Mq Al2Q3 Mqo Adsorbed
Hydrafine~ .46 1.02 l.0 28.75 Production
Production
Hydrafine~ .44 1.02 l.0 30 Dispersed,
treated
Filter cake .44 1.02 1.0 42 Undried,
undisper8ed
.44 1.02 1.0 42 Dried
undispersed
ExamPle 16
A similar test with production Hydraprint~ along
with Hydraprint~ filter cake collected from the plant
was conducted. In this test, treated Hydraprint~ from
production exhibited a 35~ adsorption capacity, while ~
the dispersed filter cake yielded a 30% adsorption ~;
~; value. Undispersed treated Hydraprint~ filter cake
~ 20 provided 41% adsorption. These results are shown in
;~ the following Table X.
~- TABLE X
;~ Hydrotalcite
% % ~ Pitch
25 ClayAl/Al+Mq Al2O3 Mqo AdSorbed
~;; Hydraprint~ .44 1.02 l.0 35 Production
Product$on
ydraprint~ .44 1~02 l.0 30 Dispersed, ~
treated ~ -
30Filter cake ~ .44 1.02 1.0 41 Dried,
undispersed
',' ,', ~
: ~ ,,
: : :.::: -
33 1 3 3 09 8 0
,~., - . ,.
Exam~le 17
The treatment of dispersed clays with hydrotalcite
was found to be le s effective than treatment of clays
devoid of dispersants. It was found that the -~
dispersion of previously treated clays rendered the
once effective pitch control clay with essentially no
adsorptive capacity. The Hydrasperse~ filter cake
trea~ed with the hydrotalcite adsorbed 47.5% of the
pitch in test systems, but the addition o dispersant
destroyed the adsorptive capacity of the product.
These results are shown in Table XI, which is as
follows:
: ,
TABLE XI
Hydrotalcite
lS 3 % % Pitch
Clay Al/Al+M~ A12O3 Mqo Adsorbed
~; Hydrasperse~ .44 1.02 1.0 47.5 Treated,
undispersed
Filter cake (control) 0
~ ,
. .- . . .: ,.
Example_18
In order to evaluate the effectiveness of the
Chlorhydrol~ and hydrotalcite treatment, treatments
with other compounds were carried out. In these
treatments, the Hydragloss 90~ and Omnifil~ clays were
treated with octyl, methyl, vinyl and monoamino silanes
by dry mixture. The only silane treatment that
yielded any adsorption was the octyl silane. On
Hydrasperse~ clay, the adsorption value is 20%, while
on Omnifil~ and Hydragloss 90~ clays, the adsorption
values wera 17.5 and 12%, respectively. The8e low
values were not considered competitive in the market.
: .'; ' ~ '' ~
''." ~'' '
34
13~98~
.
Example 19
Treatments with other compounds for comparison
purposes are listed in Table XII. In this work a
Hydrasperse~ slurry was treated with the materials
listed in the Table. From the Table it will be noted
that the treatment of the Hydrasperse~ with alum
yielded 43.75~ adsorption. However, alum was not
considered as a candidate for treatment of the clay for
pitch control because it is used as a pitch control
agent alone, and in conjunction with other chemicals
for pitch control in the absence of clay.
In the other examples, kaolin clay was treated
~; with zinc chloride and sodium hydroxide in quantities
to form monohydroxy zinc, Zn(OH)~, for cation exchange
bonding to the clay surface. The treatment yielded 45
pitch adsorption.
Most of the other materials reacted with the clay
did not provide any pitch adsorption. The last three
examples in Tabla XII involved treatment of Omnifil~
with 3 MeQMBHT and Araquad quaternary amines. Good
adsorption values were realized. However, these
quaternary treated products were very hydrophobic and
were incompatible with water systems. Therefore, no
further consideration was given to this method of
treatment. Table XII is as follows: ~-
.:~ :- -.:.,
.::: . : :
: .
l~"
-` 1 3 3 0 9 8 0 r~',#
TABLE XII
Other Treatments ~
Pitch . : -
~: ClaY Treatment TY~e Ad33iorbed
Hydrasperse~ Alum 43 75
Al-acetate
ZnO _
:Mg. Silicate -
ZnC12
2 3 ~
Zrl(OH) 45 ~
Mirapol A15 - . :
NiSO
, . . -, ,
JR-400 ",_~!'
MB2HT 46 . 25 quat .. ' -
Araquad 12-50 35 quat -~
Al formate 16 . 75
~ , .- ~. .
:'1; ~:.';
, ,.; . -
~,
36 1~309~0
Example 20
Samples of Chlorhydrol~-treated clay and
hydrotalcite-treated clays with exceptional pitch
adsorption capabilities were submit~ed to the paper
5 testing laborator~ for evaluation in iller
applications. The evaluation demonstrated that the
pitch control clays were acceptable in paper filler
applications. The specific results are set forth
below. In these studies, the Chlorhydrol~ treated clay
was a degrLt~ed ea~t Georgia crude clay slurry (Area W)
treated with 1.0 wt.% of Chlorhydrol~. The
hydrotalcite was a Hydrafine~ clay, wherein the
undispersed, undried filter cake was treated with
hydrotalcite formed in situ using 1.02% Al2O3 and 1.0~ -
MgO. These results are as follows: ~
-:
TABLE XIII
Evaluation of Optical Properties of Filled Paper Using
Clays Modified for Pitch Control
Handsheets were prepared from the following furnish: `
Pulp 70% Groundwood
30% Bleached Softwood Kraft
Freeness Xraft to 400 CSF, then blend
with Groundwood
pH Alum to pH 4.5
Retention Aid Betz 1260, 0.025% on furnish
Filler Loading 2.5, 5 and 10%
Basis Weight 50g/m (40#/ream) ~ ~ ;
: ~:
. ~ ..
: ` ~:
,
: , , :'
I
- -
~ 37
133~98~ ~
RESULTS:
:~ . RETENTION STUDY - No retention aid used RETENTION, % ~:
Area W control 46.9
~rea W Ch~orhydrol~ 53.1
: 5 Hydrafine Control 48.0
:: Hydrafine~ Hydrotalcite 52.7
Talc 60.3
Bright- Whlte- . :~
ness ness Opacity Pigment Retention
`: ~ 10 % , _~6 % ,~ % %
~ Unfilled 64.0 43.5 95.3 - .
:~ 2.5% Filler ,-.
Area W Control 63.5 42.5 96.02.56 73.1 :
Area W Chlorhydrol 63.6 42.8 95.92.79 79.6 .
15 ~ fine Control 63.6 42.9 96.22.65 75.6
Hydrafine Hydrotalcite62.9 41.7 95.92.56 73.1 .
Talc : 63.3 42.8 95.92.24 74.8
5% Filler
Area W Control 63.9 42.2 96.25.19 79.8
20 Area W Chlorohydrol 64.1 43.2 96.14.96 82.7 ~:
Hydrafine Control 64.1 43.4 96.14.66 77.6 :
Hydrafine Hydrotalcite63.8 42.7 96.44.72 78.7
Talc 63.5 43.2 95.84.54 75.7
10~ Filler :::~
~:: 25 Area W Control 64.6 44.5 96.39.89 82.4
Area W Chlorohy*rol 64.7 44.6 96.49.51 82.7 ~H~
Hydrafine Control 65.4 45.5 96.410.44 83.5
H~E~ine ~ntalcite 65.3 45.5 96.810.35 86.2
Talc 64.4 44.2 95.99.62 64.1
Example 21
In a production run, approximately 20 tons of
: dried pitch control clay were produced utilizing
degritted Area W crude clay which had been treated with ~ .
. 26 pounds of Chlorhydrol~ per ton of cIay. On
evaluation as described above, the pitch adsorption
: -capacity of the resulting product was found to be 74~,
: :
which illustrates that the invention can be carried out
on a large scale for commercial use.
The invention has been described herein with
reference to certain preferred embodiments. However,
as obvious variations thereon will become apparent to
those skilled in the art, the invention is not to be
considered a~ limited thereto.
The invention has been described herein with
reference to certain preerred embodiments. However,
as obvious variations thereon will become apparent to
those skilled in the art, the invention is not to be
~; considered as limited thereto.
` ~; '".''','','.
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