Note: Descriptions are shown in the official language in which they were submitted.
80~
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This invention relates to the use of vesiculated
polymer granules as a means of providing high opacity in
fibrous materials and, more particularly, to compositions
comprising said granules ?..,d fibrous cellulosic material of
use in papermaking.
The development of fibrous systems having a high
opacity has always been a concern to paper manufacturers.
Paper i8 typically made from fibrous cellulosic or
non-cellulosic material which may have been delignified
and/or bleached, e.g. plant matter, such as trees, cotton,
bagasse, and synthetic polymers, such as rayon. To the
aqueous fibrous suspension are generally added sizing
materials, wet and dry strength additives, defoamers,
biocides, dyes, and particularly, retention aids and
fillers. The suspension (furnish) is transferred to a
forming wire for water drainage to concentrate solids, and
subsequently dried to the desired basis weight.
The function of retention aids is to improve the amount
of fibrous material, fillers and fines retained by the
forming paper sheet, whereas fillers are used to impart
suitable optical properties, namely, whiteness, brightness,
opacity, and colour.
The degree of opacity of a particular substrate is the
result of diffuse light-scattering which occurs when visible
radiation is reflected from particles on the surface of the
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substrate and in the substrate medium itself. It has been
customary to use high density inorganic mineral fillers,
such as calcium carbonate and certain clays, to enhance the
opacity of paper sheets. However, the use of such fillers
has many disadvantages in the manufacture of paper.
In most cases the use of such inorganic mineral
opacifying materials greatly adds to the weight of the
paper. This added weight is not desirable with the
increasing market demands for production of light-weight
paper without loss of opacity.
Also, there is a practical limit to the amount of
inorganic mineral filler which can be added to the paper
owing to the fact that as the inorganic filler content
increases there is a substantial loss of the paper web
strength as the tensile strength decreases. This is caused
by the interference with the hydrogen bonding between
fibrous materials and because with increased inorganic
mineral filler content there is less fiber present in the
paper sheet to contribute to the strength.
In addition, the generally low retention of the
inorganic mineral opacifiers in the paper results in a
financial loss by virtue of the by-product waste produced
from the wire during sheet formation. More importantly,
this poor retention may result in contamination of streams,
lakes and other waterways.
Added to the foregoing disadvantages in the use of
these inorganic mineral fillers in paper, most inorganic
mineral fillers possess a low opacity-to-weight ratio when
included in paper.
It is also customary to incorporate in the dilute paper
furnish, just before formation on the wire, small amounts of
polyelectrolyte retention aids to give improved retention of
the inorganic mineral fillers on the wire during sheet
formation. For instance, British Patent No. 883l973
~2~30544
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describes the use of trace amounts of a water soluble
non-cationic linear vinyl polymer having a molecular weight
of at least 5 x 106 and mainly composed of carbamoyl-
alkylene linkages containing not more than four carbon
atoms, being added to the filler-containing aqueous
suspension of cellulose fibers prior to sheet formation, as
a retention aid.
Canadian Patent No. 1,046,815 describes a method of
manufacturing paper sheet by means of the formation of
filler/polymer conglomerates formed by contacting in an
aqueous medium a mineral filler with a water soluble polymer
having a molecular weight of at least 2 x 106 and possessing
a zeta potential of -40 to +40 millivolts.
British Patent No. 1,353,015 describes a method of
coating calcium carbonate particles with a selected gellable
hydrophilic organic material and thereafter causing the said
material to gel so as to form aggregates of gelled
hydrophilic material and calcium carbonate particles. Under
certain conditions aggregates of a fibrous character may be
formed. The use of the coated calcium carbonate filler is
stated to give a slightly increased retention without
reducing the paper strength.
It has also been suggested that microencapsulated
polymers can be incorporated in a paper sheet to enhance
opacity. These substantially spherical polymers can be
added in the dilute paper furnish before formation on the
wire as substitutes for inorganic mineral fillers. These
microcapsular opacifiers can also be incorporated in
coatings for fibrous or non-fibrous substrates. For
example, Canadian Patent No. 856,861 describes polymer
granules with a vesiculated structure that can be utilized
in a coating composition and polymer films to impart an
opacity which is greater than non-vesiculated granules of
the same composition.
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u.s. Patent No. 3, 853, 579 and 3, 779, 800 describe a
light-weight coating comprising a binder and small
colourless plastic, polymeric particles which remain
discrete and retain a diameter of about one wave length of
visible light. The coating comprising the above mentioned
materials may then be applied to a paper substrate in a
conventional manner.
U.S. Patent No. 3,816,169 describes a coating of
discrete, substantially spherical, air-containing
microcapsules having substantially continuous organic,
polymeric, solid walls, an average particle diameter of
below 2 microns and having pigment particles incorporated in
the microcapsular structure. The coating comprising the
above mentioned materials may be applied on fibrous and
non-fibrous substrates.
It is an object of this invention to provide a means
for increasing the opacity of fibrous paper sheets, without
significantly increasing the weight of said paper sheet to
an extent not heretofore possible.
It i8 another object of this invention to improve the
optical property of opacity without decreasing the web
strength of a paper compared to a paper made with
conventional inorganic mineral fillers.
Still another object of the present invention is to
provide a reduction in the amount of opacifier which is lost
during the formation of paper on the forming wire.
It is also an object of the present invention to
provide a means for increasing the retention of pigmented
and/or non-pigmented vesiculated granules.
~hus, it is a primary object of the present invention
to provide an aqueous fibrous composition suitable for
conversion to a sheet or roll of paper having reduced
amounts of opacifying material, particularly pigment.
Accordingly, the invention provides an aqueous
composition for use with a fibrous cellulosic or
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non-cellulosic material, said composition comprising
vesiculated polymer granules and a retention aid; said
granules having a mean diameter of 1 to 500 microns, the
ratio of the granule diameter to the mean vesicle diameter
being at least 5:1, the maximum diameter of the vesicles
being 20 microns and the volume of the vesicles being from
5-95~ of the volume of the granules.
By vesiculated polymer granules is meant granules of
polymer, preferably spheroidal granules, which have a
cell-like structure, the walls of which are provided by the
polymer. The granules comprise a plurality of cells or
vesicles, that is they are not mono-cellular or balloon-
like, and although the vesicles are not necessarily of
uniform size, the ratio of the diameter of the granule to
the mean individual vesicle diameter is generally at least
5:1. The vesicles typically occupy from 5 to 95% of the
total volume of the granules. Low vesicle volumes are
usually associated with granules of high mechanical strength
which are particularly useful for some applications, but to
achieve the most useful opacifying effects the vesicles
typically occupy at least 20~ of the total volume of the
granules, preferably 20-75% of the volume.
Preferably, each vesicle as hereinbefore described
should be enclosed in a continuous shell of polymer. If the
granules are produced directly in their required physical
size and shape, e.g. by a suspension polymerization process,
there will be a random distribution of imperfect vesicles
formed therein. On the other hand, if the granules are
prepared by, for example, the mechanical degradation of bulk
vesiculated polymer, substantially all of the vesicles
adjacent to the outer surface of the granules will be
imperfect; that is, part of the shell of polymer which
preferably encloses them will be broken away.
Although the shape of the granules is not critical in
achieving some increase in opacity we have found that
spheroidal structure gives the best results.
. , .
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The term "retention aid" is a well-known term in the
pulp and paper art and means a material that has a
coagulating or flocculating effect or an electrochemical
interaction on the fibrous material used as the major
component of paper to effect increased retention of the
fines of the fibrous material, pigment and the like.
Embraced with this term are the three main categories
of retention aids, namely, inorganic salts, organic
polyelectrolytes of the non-ionic, cationic, anionic and
amphoteric types; and natural organic polymers, e.g.
starches and gums. Examples of inorganic salt retention
aids are alum and sodium aluminate. Examples of organic
polyelectrolytes include polyacrylamides, polyethylene-
imines, polyamines, polyamideamines, of high, medium, and
low molecular weights. Also, included are quaternized
organic polyelectrolytes or natural organic polymers or
quaternized non-ionic, cationic, anionic and amphoteric
derivatives thereof.
Examples of retention aids of use in the practice of
the invention include:
quaternized polyacrylamide (Q-PAM)
polydiallyldimethyl ammonium chloride (DAD-MAC)
dimethylamine epichlorohydrin (DMA-EPI)
ALUM-aluminum sulfate (A12(SO4)3 18H20)
Thus, we have now found in accordance with the present
invention that polyelectrolyte retention aids have the
capability of adhering thereto pigmented and/or
non-pigmented vesiculated granules. It is believed that the
aforementioned granules are retained in position on the
fibers by attractive forces such as electrostatic attraction
between the vesiculated granules, fibers and the retention
aid by bridging effects. Such conglomerates can be used in
the manufacture of paper sheet in order to increase the
vesiculated granule content of the sheet. S~rprisingly, it
has been found that when these pigmented and/or
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non-pigmented vesiculated granules are incorporated into
aqueous paper pulp with the polyelectrolyte retention aid
added to the furnish before being formed into a paper sheet
on the forming wire, the resulting paper sheet achieves an
opacity increase heretofore unobtainable.
Thus, in a further feature the invention provides an
aqueous composition as hereinbefore defined further
comprising a fibrous cellulosic or non-cellulosic material
in the form of a paper pulp.
The invention is also of use when inorganic mineral
pigment fillers are present in the paper.
The vesiculated granule opacifiers of use in the
present invention comprise granules of polymer, essentially
spheroidal, which have a cell-like structure, the walls of
which are provided by the polymer. This cell-like structure
is what is referenced to by the term vesicle. The granules
are comprised of many vesicles, that is they are not
mono-vesiculated or balloon-like, and although the vesicles
are not necessarily of uniform size, the ratio of the
diameter of the granule to the mean individual vesicle
diameter should be at least S:l. The vesicles should occupy
from 5 to 95% of the total volume of the granules. Low
vesicle volumes are usually associated with granules of high
mechanical strength which are particularly useful for some
applications. To achieve the most useful opacifying effects
we prefer that the vesicles occupy at least 20% of the total
volume of the granules, preferably 20-75% of the volume.
The granules have substantially continuous, solid walls
and have a predetermined particle size. Broadly, the
granules may have a mean diameter of 1 to 500 microns. In
general we find that granules having a mean diameter of 1 to
100 microns are of the most value as opacifying agents.
Preferably, when used as opacifying agents, essentially no
granules should exceed the upper dimension limits by more
than 20 microns. It is to be understood that the above
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limits may be exceeded by a minor portion of granules which
lie outside the stated dimensions.
The term "substantially continuous solid walls", as
employed herein, is intended to include solid walled
granules which are still sufficiently porous to permit the
escape of vaporizable material in gaseous form therethrough
upon the application of heat. Ideally each vesicle should
be enclosed in a continuous solid wall of tightly cross-
linked polymer, but it is not always essential to achieve
this. For example, if the granules are produced by an
emulsion process, there will be a random distribution of
imperfect vesicles formed within the granule. As a further
example, if the granules are prepared by the mechanical
degradation of bulk vesiculated polymer, it is possible that
lS many of the vesicles contiguous with the outer surface of
the granule may be imperfect. This may be observed as
vesicles with part of the wall of polymer which preferably
encloses them broken away.
The vesicles, which are usually spherical in shape,
should have a diameter of less than 20 microns and
preferably less than 5 microns. The maximum diameter will
clepend to a degree on the average diameter of the granule.
We have found that the opacifying effect of the granules
tends to increase as the diameter of the individual vesicles
decreases. The optimum light scattering effect of vesicles
containing air is achieved in the range of 0.2 - O.S micron
diameter.
The vesicles may be essentially gaseous; that is, they
may be bubbles of air or other gas. In aqueous compositions
they may be saturated with vapour, for example, with vapour
diffusing into the vesicles, through their polymeric walls
from the liquid medium in which the granules are suspended,
or may be at least partially filled with liquid taken in
from the liquid medium in which the granules are suspended.
When the granules are to be used in a paper sheet, we prefer
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C-I-L 711
that most of the liquid in the vesicles be sufficiently
volatile to diffuse out of the granules in contact with air.
That is, when the paper sheet has been formed on the wire
and is then dried in air, or optionally at an elevated
drying temperature, the granules provide essentially gaseous
vesicles and in this form contribute an opacifying effect to
the paper sheet.
In a further feature of the invention, the vesicles
contain particulate solids. The particulate solids may be
dispersed therein in a liquid in which the polymer is
insoluble or may be associated with essentially gaseous
components alone. For example, the particulate solids used
in the granules may be any suitable organic or inorganic
pigment. Such pigments include those finely divided
materials which have been conventionally employed for the
purpose of enhancing optical properties, such as opacity, in
a paper sheet. Suitable pigments include, for example,
Ti02, CaCO3, A12O3 3H2O, barytes (BaSO4), clay, ZnO, ZnS,
CaSO3, CaSiO3, talc, and the like. Preferred inorganic
pigments for the purpose of the present invention are TiO2,
CaCO3, A12O3-3H2O, BaSO4, clay and ZnO, with titanium
dioxide being particularly preferred.
Any desired pigment particle size may be used, as long
as it i~ suitable for incorporation into the vesicular
structure. Thus, for example, titanium dioxide having a
mean particle size between 0.1 and 0.35 micron is highly
suitable for the purposes of this invention.
The invention is not limited, however, to the use of
the above types of pigment and unusual effects may be
produced in a paper sheet by the use of granules in which
the pigment is at least in part coloured. For example, the
pigment may comprise iron oxide, phthalocyanine,
quinacridone, cadmium sulphide, or u.v. brighteners.
Chemical or physical tagging agents may be included in the
vesicles or in the polymeric cellular material dyes, u.v.
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C-I-L 711
absorbers, u.v. brighteners, fluorescent materials and like
additives.
The particulate solids need not be pigments in the
generally understood meaning of the term. For example, the
particulate solids may be extenders, e.g. bentonite or
clays.
The particulate solids may be dispersed in a suitably
volatile liquid which subsequently diffuses out of the
granules to leave the dry particulate solids therein. We
limit the particulate solids concentration for the purposes
of this invention to a maximum of 60% by volume of the
vesicle and while the size of the chosen particles depends
on the actual vesicle diameter, we prefer that the maximum
particle diameter should be 1 micron.
It is a particular feature of the present invention
that when these particulate solids are incorporated into the
vesicles of the granules, in this form the granules
contribute an opacifying effect to the paper sheet.
The technique of preparing vesiculated materials from
carboxylated, unsaturated polyester resin by emulsifying
water into the polyester resin in the presence of a base and
then polymerizing the resin is known. A further advance in
this technique is the preparation of what is known as
"double emulsions~, that is, emulsions wherein the disperse
phase is itself an emulsion. For instance U.S. Patent No.
3,255,137 describes the preparation of porous polymeric
materials made by dispersing water in a polymerisable
liquid, dispersing the resulting emulsion in water and
po~ymerising the liquid. U.S. Patent No. 3,822,224 further
defines a process of preparing vesiculated polyester resin
granules by the dispersion and selection of a styrene
solution of carboxylated unsaturatd polyester resin in an
aqueous continuous phase in the presence of a selected base.
The process may be refined to a greater degreee by careful
selection of both polyester acid value and base type. U.S.
28~)5~
C-I-L 711
Patent No. 3,879,314 outlines the use of bases which are
water-soluble polyamines having at least three amine groups
per polyamine molecule and a pKa value of between 8.5 and
10.5.
Although it is not intended to limit the present
invention to any particular process of manufacture or choice
of carboxylated, unsaturated polyester resins of which the
vesiculated beads are comprised, for the purpose of this
invention the process of preparation of vesiculated
polyester resin granules as outlined in Canadian Patent No.
1,139l048 is preferred.
This process comprises the following listed steps:
1. Preparation of a stable emulsion of water in a
polyester solution by emulsification of water into a
solution in essentially water-insoluble ~ , ~-ethylenically
unsaturated monomer of a carboxylated unsaturated polyester
resin. The presence of a base is required to give a stable
emulsion of water in the polyester solution.
2. Droplets of emulsion are formed when the emulsion is
dispersed into water. A stabiliser is required to be
present in the water before disperson of the emulsion.
3. Polymerisation by addition reaction is initiated within
the droplets to convert them to cross-linked vesiculatd
polyester resin with the following characterization:
(i) the acid value of the polyester is from
5-5Omg.KOH/gm.
(ii) the base is a metal oxide, hydroxide or salt.
Suitable metal cations include, for example,
calcium, magnesium, barium, titanium, zinc, lead,
strontium and cobalt. Suitable metal salts should
have the pKa value of the conjugate acid of the
anion greater than 2.
(iii) the amount of base present should be from 0.3
equivalents of metal cation per equivalent of
polyester carboxyl group to the quantity required
for the complete neutralization of all the
carboxyl groups.
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It is also provided that an agueous slurry of stable
cross-linked polyester resin vesiculated granules can be
prepared by the above mentioned process.
The polyelectrolyte retention aids of use in the
S present invention include several materials which have been
conventionally employed for wet end addition on a
papermaking machine. These materials may include inorganic
polyelectrolytes. For example, alum or sodium aluminate;
natural organic polymers, for example, gums, starches, and
derivatized starches; synthetic organic polyelectrolytes,
for example, polyacrylamide, diallyldimethyl ammonium
chloride, polyethyleneimine, amines of epichlorohydrin, and
methacryloyloxyethyl trimethyl ammonium methosulfate.
Preferred polyelectrolyte retention aids for the purpose of
the present invention are synthetic organic polyelectrolytes
with polyacrylamides, diallyldimethyl ammonium chloride and
dimethylamine epichlorohydrin being especially preferred.
The ter~ ~polyelectrolyte" as employed herein is
intended to include an organic polymer which contains
sufficient charged functional groups, or neutral functional
groups capable of becoming charged in aqueous solution, to
impart water solubility to the poly.ler and to allow it to
behave as an electrolyte. Although it is not intended to
limit the present invention by any particular theory, it is
postulated that the retention aid functions through various
complex mechanisms. The modes of operation of retention
aids are still theoretical in nature. Mechanisms of
function include, for example, filtration or sieving
effects, mechanical entrapment of particles, polyelectrolyte
adsorption resulting in charge neutralization phenomena
and/or particle bridging.
The polyelectrolyte retention aids used in the present
invention may also be non-ionic in nature.
The non-ionic polyelectrolytes bear no formal charge
but are capable of developing a transient charge in aqueous
solutions. This group of retention aids include, for
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example, polyalcohols, polyethers, polyamides, poly N-vinyl
hetercyclics and polyacrylamides. Preferred polyelectrolyte
retention aid of the non-ionic type for the purpose of this
invention are polyacrylamides, which may be, for example,
homopolymers or copolymers of acrylamide. The molecular
weight of these polymers are generally high, i.e. in excess
of 1 million. The homopolymers of acrylamide, which are
normally essentially non-ionic contain the repeating unit:
-- -( CH2 C ) -
I
C = O
I
NH2
wherein R may be hydrogen (polyacrylamide) or methyl
(polymethylacrylamide).
The polyelectrolyte retention aids used in the present
invention may also be anionic, which may contain negatively
charged functional groups. This group of retention aids are
normally used in an acidic papermaking machine and must
contain a positively charged multivalent ion to provide
bridging betw~en the high molecular weight anionic polymer
and the anionic fibers and fines in the furnish.
This group of anionic retention aids may include, for
example, acrylamide/acrylic acid copolymers, and hydrolyzed
polyacrylamides. The copolymers of acrylamide and acrylic
acid may be represented by the repeating unit:
H2 ICH )m ( CH2 - CH
;:=0 C=O
1H2 H
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C-I-L 711
The carboxylic acid group ICOO ) may be replaced by
sulphonic acid (SO3 ) or phosphonic acid (PO3 ), wherein
each acid group may be comprised of an ammonium, alkali
metal, amine or substituted amine salt of said group. The
ratio of m to n may vary to give a weight percent ratio
between 100:0 and 50:50 i.e. up to 50 mole ~ of anionic
groups may be present in the polymer.
The polyelectrolyte retention aids used in the present
invention may be cationic in nature.
Cationic polyelectrolytes contain a positively charged
functional group wherein the formal positive charge may
reside on, for example, a tri-substituted sulphur known as
sulphonium, a tetra-substituted phosphorous (phosphonium) or
a tetra-substituted nitrogen (ammonium). Accordingly,
suitable cationic polyelectrolytes include, for example,
methacryloyloxyethyl trimethyl ammonium methosulphate
(METAMS), vinyl benzyl trimethyl ammonium chloride (VBTAC),
dimethyldiallyl ammonium chloride (DMDAAC), and
3-acrylamido-3-methyl butyl trimethyl ammonium chloride.
Preferred cationic polyelectrolytes for the purpose of this
invention are polymers containing the ammonium group, and
polymers containing a quaternary ammonium salt which retains
its positive charge in acid, neutral or alkaline papermaking
systems being especially preferred.
The use of cationic polymers offers inherent advantages
as compared to non-ionic or anionic polymers in most
papermaking systems. It is known that the fine solids
fraction, materials of less than 75 micron size, of most
conventional papermaking systems carry a residual negative
charge. Cationic polymers can bond or bridge directly with
this fines fraction, eliminating the need for supplemental
ions in the system.
The polyelectrolyte retention aids used in the present
invention may also be amphoteric, which may be defined as
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polyelectrolytes which contain both positive and negative
functional groups in the same polymer chain. The ratio of
cationic to anionic functional groups may be such that one
is predominant.
The polyelectrolyte retention aids used in the present
invention may also be defined according to the mechanism by
which the polymer is made. Accordingly, a suitable
mechanism of formation may be vinyl addition polymerization
which include, for example, acrylamide/acrylic acid
copolymers, acrylamide/METAMS copolymers and
acrylamide/DMDAAC copolymers. A further example of
formation mechanism polymers are condensation polymers, for
example, polyethyleneimine and polymers of an amine and
epichlorohydrin. For the purpose of the present invention
dimethylamine epichlorohydrin is being especially preferred.
The vesiculated polymer granules/polyelectrolyte
retention aid conglomerate compositions of this invention
can be prepared by continuous or metered addition of an
aqueous solution of the polyelectrolyte retention aid, for
example, dimethylamine epichlorohydrin to a paper furnish
which contains the vesiculated polymer granules, either
pigmented, non-pigmented or a blend thereof, and then feed
of the resulting material to the wet end of a papermaking
machine.
If desired conventional wet-strength agents (such as
polymeric resins) or dry-strength agents (such as natural
and modified starches and gums) may be present during the
formation of the granule/polyelectrolyte polymer
conglomerates.
The papermaking process of the invention can be carried
out using a conventional furnish formed in part or totally
from hardwood, softwood and recycled pulps and/or broke if
desired incorporating an internal sizing agent, for example,
natural and fortified rosins or an aqueous ketene dimer
emulsion.
.. , , ~ ..
16 ~.Z8~
C-I-L 711
The granule/polyelectrolyte polymer conglomerate
compositions of use in accordance with this invention can be
employed in an alkaline papermaking system, that is systems
in which the paper furnish is maintained at a neutral or
alkaline pH value; alternatively, the
granule/polyelectrolyte polymer conglomerates may be used in
an acid papermaking system, that is systems in which the
paper furnish is maintained at an acid pH value.
In yet a further feature the invention provides paper
containing dispersed therein vesiculated polymer granules
and a retention aid as hereinbefore defined.
The following non-limitative examples illustrate how
the invention may be carried into effect.
The following Table lists the materials used in the
preparation of 10 microns (95 percentile) diameter maximum
5.2 microns mean average diameter pigmented vesiculated
polyester resin granules of use in the practice of the
invention.
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GROUP MATERIALPARTS (W/W)
A water (1) 3.088
surfactant (2) 1.595
antifoam 0.016
B titanium dioxide pigment (3) 10.601
C water 1.029
D polyester (45) 8.686
styrene ~6) 4.8
magnesium oxide` 0.045
E water 1.647
F hydroxy ethyl cellulose (8)
poly (vinyl alcohol) solution(l) 0 103
water 30.934
G water 24.701
H cumene hydroperoxide5(90) 0.206
diethylene triamine(11) 0.051
ferrous sulphate 0.003
I bactericide I13)
ammonia solution~14) 2 000
(1) A 28% wt. solids ammonium salt of a sulphated
alkylphenoxypoly(ethyleneoxy)-ethanol
(ex. GAF Corp. Alipal* Co-436)
(2) Antifoam Foamaster* NSI (ex Diamond Shamrock~
or Bevaloid* 60 (ex. Imperial Chemical Industries
PLC U.K.)
(3) Titanium dioxide pigment TiPure* R900
(ex. DuPont)
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(4) A 65% weight solids solution of a 3.74/2.34/0.912
(molar) propylene glycol/maleic anydride/phthalic
anhydride solution in styrene
(5) Styrene (ex. Dow Chemicals)
(6) Magnesium oxide Maglite*D (ex. Merck)
(7) A 1.5% weight solids aqueous solution of Natrosol*
250HR (ex. Hercules)
(8) A 7.5% weight solids aqueous solution of
Poval* 224G
(9) A commercially available 78% weight active
ingredients (ex. Pennwalt)
(10) Commercially available material
(ex. Union Carbide)
(11) Commercially available material (ex. J.T. Baker
Chemical Co.)
(12) Bactericide Proxel* GXL (ex. Imperial Chemical
Industries PLC England)
(13) A commercially available concentrated 0.9
ammonia solution.
(14) A commercially available thickener Acrysol*
ASE-60 (ex. Rohm & Haas)
* Trade Mark
19 ~28~)S44
C-I--L 711
The pigmented vesiculated polyester resin granules were
made as follows:
Materials "A" were mixed and filler "B" added to "A"
with stirring. Stirring was continued at high speed until
the filler was completely dispersed, then water "C" was
added to give a millbase.
Materials "D~ were mixed until the magnesium oxide was
completely dispersed and water "E" was added and emulsified
into "D" with high speed mixing.
The millbase was added to this emulsion and similarly
emulsified into it until the dispersed particles of the
millbase were at least 1 micron in diameter. This is
referred to as "the first emulsion".
Materials "F" were blended and the first emulsion added
to it under high speed stirring. The stirring was continued
until the globules of the first emulsion were 10 micron in
diameter. All but one part of water "G" was then added.
This is referred to as "the double emulsionn.
Diethylene triamine and ferrous sulphate of "H" were
premixed in 0.5 parts each of water "G" and materials "H"
added to the double emulsion in the order listed above with
sufficient stirring to incorporate them. Stirring was then
stopped and the mixture was allowed to cure overnight.
Bactericide of "I" was added under stirring, the pH of
the mixture adjusted to 8.5-9.5 with the ammonia solution,
and the viscosity adjusted to a workable thickness with the
thickener.
Further vesiculated polyester resin granules were
produced as outlin~d in Examples 2, 3, 4 and 5 of Canadian
Patent No. 1,139,048.
Vesiculated polyester resin granules were prepared as
outlined hereinabove except that the particle size in the
second emulsion was 25 microns (92 percentile) maximum
diameter and 12.7 microns mean average diameter.
~ . ' , .,
-- . .
-20- ~2 8~ S~ ~
C-I-L 711
Vesiculated granules were prepared as outlined
hereinabove without filler present in the first emulsion
stage. The vesiculated granules prepared without filler are
hereinafter referred to as "non-pigmented vesiculated
granules" to aid in the following commentary when both
pigmented and non-pigmented vesiculated granules are in use.
Table A outlines some of the physical parameters
obtained when pigmented vesiculated granules are prepared in
accordance with the aforementioned methods of preparation
for 10 microns (95 percentile~ maximum diameter granules,
and 25 microas (92 percentile) ~ _ es.
-21- 128054A
C--I--L 711
,
TABLE A
Pigmented
Vesiculated Granules
10 m 25 m
density of dried granules 0.59 g/ml 0.70 g/ml
% vesiculation (1)65% 60%
weight solids 21.2~ 23%
volume solids 36% 33~
maximum granule size(2)12 micron 32 microns
median granule size5. 2 micron12. 7 microns
minimum granule size 3 micron 4 microns
vesicle pore size (3) 0.5-3.0 micron 0.5-3.0 micron
surface pores on
granules<0.2 micron <0.2 micron
thickness of granule walls 0.1-0.5 micron 0.1-0.5 micron
.
Note:
(1) vesiculation determined by mercury porisimetry
(2) granule size determined by Laser Diffraction
Granulometer
(3) ~nternal diameters measured using Scanning
Electron Microscopy
The following series of experiments employ the
following terms:
Freeness of pulp is a measure of the drainage rate of
water through the pulp and is measured in accordance with
the TAPPI (Technical Association of the Pulp and Paper
Industry) Standard T227 om-75 and is also referred to as
Canadian Standard Freeness.
15 Opacity of the paper sheet is expressed as ~ opacity
and measured in accordance with CPPA (Canadian Pulp and
Paper Association) Standard E-2 using an FMY/C filter for
contrast ratio measurements.
-22- ~Z80S~
C-I-L 711
The term handsheet is used to refer to a paper sheet
made in accordance with and employing equipment described in
the TAPPI standard T205 om-81.
Conditioning refers to the conditioning atmosphere of
23.0+1.0 degrees Centigrade and 50.0~2.0 percent relative
humidity that the paper sheets are exposed to in accordance
with TAPPI standard T405 om-83
Handsheets were prepared by the following general
procedure.
The furnish or solids in the pulp slurry comprised 100
percent by weight of fully bleached chemical hardwood pulp.
The pulp was a commercially produced kraft pulp, and was
subsequently beaten to a Canadian Standard Freeness of 325
ml. After beating, individual samples of pulp were
disintegrated, stirred, and varied amounts of fillers and
retention aids added. The pH was adjusted for either acid,
neutral, or alkaline conditions to simulate industrial
headbox conditions. The furnish was subsequently passed
through a sheetmaker and the resultant handsheet pressed and
conditioned.
The following series of experiments were performed.
All series except Series D involved four commercially
available retention aids.
Series A were performed with a furnish comprising a
hardwood pulp.
Series B were performed with a furnish comprising a
hardwood pulp, and a filler of anatase titanium dioxide.
Series C were performed with a furnish comprising a
hardwood pulp, and a filler of vesiculated polymeric
granules of median particle size 5 microns.
Series D were performed with a furnish comprising a
hardwood pulp, and a filler comprising vesiculated polymeric
granules of median particle size of 5 microns.
Series E were performed with a furnish comprising a
hardwood pulp, and a filler of pigmented (rutile titanium
-23- lZ8054~
C--I--L 711
dioxide) vesiculated polymeric granules of median particle
size 5 microns.
Series F were performed with a furnish comprising a
hardwood pulp, and a filler comprisin`g pigmented (rutile
titanium dioxide) vesiculated polymeric granules of median
particle size 5 microns and anatase titanium dioxide.
Series G were performed with a furnish comprising a
hardwood pulp, and a filler comprising pigmented (rutile
titanium dioxide) vesiculated polymeric granules and
non-pigmented vesiculatd polymeric granules both of median
particle size of 5 microns.
Series H were performed with a furnish comprising a
hardwood pulp, and a filler of pigmented vesiculated
polymeric granules of median particle size of 12 microns.
Series I were performed with a furnish comprising a
hardwood pulp, and a filler comprising pigmented (rutile
titanium dioxide) vesiculated polymeric granules of median
particle size 12 microns and rutile titanium dioxide.
Series J were performed with a furnish comprising a
hardwood pulp, and a filler comprising pigmented (rutile
titanium dioxide) vesiculated polymeric granules of median
particle size 12 microns and non-pigmented vesiculated
polymeric granules of median particle size of 5 microns.
EXAMPLE 1 - (Series A)
The hereinabove general procedure for the preparation
of furnishes was carried out to prepare furnish comprising
fully bleached chemical hardwood kraft pulp and further
comprising four, separate samples of various commercially
available retention aids.
Sample 1 retention aid was added as a 1 volume percent
solution of a low molecular weight, high activity, liquid
cationic quaternized polyacrylamide (Q-PAM). The addition
level was 4 pounds per ton of pulp oven-dried weight.
-24- lZ805~'~
C--I--L 711
Sample 2 retention aid was added as a 1 volume percent
solution of a moderate molecular weight, polycationic
polymer of diallyldimethyl ammonium chloride (DAD-~AC). The
addition level was 4 pounds per ton of pulp oven-dried
weight.
Sample 3 retention aid was added as a 1 volume percent
solution of a highly charged moderate molecular weight
cationic polymer of dimethylamine epichlorohydrin (DMA-EPI).
The addition level was 4 pounds per ton of pulp oven-dried
weight.
Sample 4 retention aid was a 1 weight percent solution
of Alum (aluminum sulphate A12(SO4)3 18H20) in de-ionized
water. The addition level was 2 weight percent on pulp oven
dried weight.
The furnish containing 0.8 dry weight percent of fully
bleached chemical hardwood kraft pulp at a Canadian Standard
freeness of 325 milliliters in 2 liters of de-ionized water
was disintegrated for 5 minutes. The furnish was then
placed under a mixer. Eight samples were prepared in an
identical manner.
The first run was adjusted to pH 4.5 with dilute
sulphuric acid. Runs 2 to 5 inclusive contained one of the
retention aids, and the pH adjusted to 4.5 with dilute
sulphuric acid. Runs 6 to 8 inclusive were adjusted to
various pHs with either dilute sulphuric acid or dilute
sodium hydroxide.
Results are shown in Table 1. - ______
____,
~28C)5~ll
--25--
C--I--L 711
~ ~ o ~I ,
dP
~ ~ ~ u) O
~ R
:, I ~ 1 1 0 ,,
D
a ~S
. ~
-26- l2aos~
C--I--L 711
EXAMPLE 2 - (Series B)
Runs 9 to 26 inclusive were prepared as in the above
mentioned general procedure. The furnish preparation and
retention aids used were as those described in Example 1,
except a filler (anatase titanium dioxide) was added. The
anatase titanium dioxide was added as an aqueous mill base
prepared by high shear dispersion of a slurry comprising 70
weight percent Tioxide A-HR anatase titanium dioxide; 4.2
weight percent of a 3.3 weight percent solution of
tetra-sodium pyrophosphate (TSPP-Na4P207 10 H20), and 2.8
weight percent of de-ionized water.
The components in the furnish were added in the
following order: pulp, filler,~retention aid, then either
dilute sulphuric acid or dilute sodium hydroxide as required
for pH adjustment.
The filler level was evaluated at two additional
levels. The first level was 5 weight percent of filler on
the oven dry weight of the pulp in the furnish and the
second level was 10 weight percent of filler on the oven dry
we,ight of the pulp in the furnish.
The results are shown in Table 2. ",
C
~28054'~ C- I-L 711
_ _ _
O ~ r-- ~--1 ~1 1~ ~I N ~ 1~-
& ~ ~ ~ ~ u~ c~ ~ o ~ o ~ r- ~r ~ ~ er 0~
, .
~ I l ~ ¦ N l l l l
~3
~ ~ I I I I I I I I I ~
m ~ ~ I I I I I I I I ~r I I I I I I I I I
~r; ~ .
~ ~ I IIIII~rIIIIIIIIII
P;
u~ ~ u~
O ~ . ~ l l l l l l l l l l l l l l l l l l
~ ~
L P~ ~ ~ l l l l l l l l l l l l l l l l l l
m ~
E~ ~ O m : ,~ ::: c: ~: : ~:
_
~ ~ ~ = . = . . C : .
+
i~ o ~ N ,~ ~ O _~ N ~ ~ N ~`I
1280~
-28-
C-I-L 711
EXAMPLE 3 -- (Series C)
Runs 27 to 39 inclusive were prepared as in the above
mentioned general procedure. The furnish preparation and
retention aids used were as those described in Example 2
except the filler used was vesiculated polymeric granules.
The vesiculated polymeric granules were used in the emulsion
form as prepared and described in the foregoing text. The
order of addition of the furnish components, and the filler
levels used are as those described in Example 2.
Runs 27, 28, and 29 demonstrate the % opacity
contributed to the pulp furnish by the vesiculated polymeric
granules in the absence of a retention aid. Runs 30 to 32,
34, 36 to 39 inclusive demonstrate the % opacity contributed
to the pulp furnish by the vesiculted polymeric granules in
the presence of one of the retention aids as described in
Example 1. Runs 28, 33 and 35 demonstrate the effect of
altering pH.
The results are shown in Table 3.
-
-29- ~L2805~L~
C-I-L 711
r o~ r o~ 0
~ ~ er ~ ~ ~ ~ o
u
~ ~ ~ ~ Lr~ r ~ 0 n a~ In
0~o
_
~I) ~ l l l l l l I ~ N I ¦ ¦ t~
0 H
~ ~ l l l l l l l l l l
O ~¢ Z:i I I I I I ~r ~ I I I I ~ I
U~ ,0
~ ~ 3 I I I I r
H p:;
~; ~ I I I ~ I I I I I ~ I I I
U~ _
_ ~ l ll l l l l l l l l l l
.
:5 ~ dP dP dP doP
r~ ~ U~
~C ~
~ ~ U~ : dP
~ 0
~ 0 ~ ~
+~
r~ o
r~
'~ 2805~4
C-I-L 711
EXAMPLE 4 - (Series D)
Runs 40 and 41 were prepared as in the above mentioned
general procedure. The furnish preparation and order of
material addition were as those described in Example 2
except that the filler used was a 1:1 weight ratio blend of
vesiculated polymeric granules and anatase titanium dioxide.
No retention aids were used in this Example.
The results are shown in Table 4, also included are
runs 27 and 29 of Series C, and runs 9 and 11 from Series B
10 for ease of comparison of results. ~
-31- C-I-L 711
1~8~5~Z~
~ OD
& t~
. ~P
_
~ ~,. = =
o ~L I O I 1_, ,
~: ~ I l l l l I
' ~_" ~
~N Ul t ~ ,, t U,
t ~ ~ I dP * , o dP
~ u~ ~ I _l In
~¦ a~ ~ '
_ ~ e
.
a~
æ 0 0 g ~ ~ ~
~-a ~ 0 o~ ~ 0
0
. ~ (~ ~ ~ ~ N ~ ~ ~ Q,
,~ n ~ O
h
~ E~ ~ ~ ~ E~ P. ~4 ~ ~ E~
r~ I~ O
o~
. ,
~Z8~5
--3 2-
C-I-L 711
EXAMPLE 5 - (Series E)
Runs 40 to 58 inclusive were prepared as in the
aforementioned general procedure. The furnish preparation,
retention aids used, and order of material addition were as
those described in Example 2 excepting that the filler used
was pigmented (rutile titanium dioxide) vesiculated
polymeric granules. The granules used were in the emulsion
form as prepared and described in the foregoing text. The
filler levels were 5 and 10 weight percent on pulp weight.
The results are shown in Table 5, also included are
runs 9, 11 and 22 from Table 2 for ease of comparison of
-33- :~LZ80544 C-I-L 711
~ u~ r o er o~ ~ ~o ~
H Ul ~ ~ ~~ D ~ ~ O O ~9 ~r ~D 11~ ~ IJ~ O el~
~ ............ ~
O r 1` ~ r` 1` t~ 1` 1~ 1` r- r` o~ 1` 1` 1` GO 0~ 0~ OD r`
d~ _ .
~ ~ I I I I I I I I I I I I I I I I I
O ~ I I I I I I I I I I I I I I ~ I I I I
O H
O
IIIIIIIlerlIIIIIIIOO
~;
~ IIOIOOOO~rOOIIOIIOIII
U~
~ 0~ I dP t 1 ,, 1 1 1 1 1 1, O O O O O, O u~
E~
-~.q ~ g~ IIIOIIIIIIIIIIIIIIII
O ~ d~ dP dP
n _~ ~ d~ 1 dP
~ U~=: _1:::: ~:::::: _1:::
~ ¦ ~ N ¦
. ~
~ ~ ~ ~ ~ ~i In ~ I` 0~ a~ o ~
,
~L2a~5~
C-I-L 711
EXAMPLE 6 - tSeries F)
Runs 59 to 65 inclusive were prepared as in the
foregoing general procedure. The furnish preparation,
retention aids used, and order of material addition were as
those described in Example 2 excepting that the filler used
was a 1:1 weight ratio blend of pigmented (rutile titanium
dioxide) vesiculated polymeric granules and anatase titanium
dioxide. The granules used were in the emulsion form as
described in the foregoing text. The anatase titanium
dioxide was used as a mill base disperson as described in
Example 2. The filler levels were 5 and 10 weight percent
on pulp weight.
The results are shown in Table 6, also included are
runs 9 and 11 from Table 2 and runs 42 and 44 from Table 5
for ease of comparison of results.
1 280~;4f~ C-I--L 71. ~
u~ D O In D
n o ~
~r ~ ~r~ c~ ~ ~ ~ r-
& I`
,
~ U~
d'
Q) ~ l l l l l l l l l l
u) ~ II I I I I I I N
O H
a
.~ ~ t ~I t I I I t
o . _
~ ~
a) ~ l ll l l l l l l l
~ ~ I II I II I ~r I I I
~; _.~
~q ~ l l l l l l l l l l
rLl ~ I I I I I I ~ I I I I
H _ dP
~; ~ oP I ~ O I d~ ~
~ .~ u~
U~
:~ ~1 I I I I I I I I t I t
.
o ~
10 dP ~ -
I ~ dP dP
_l ~ :~ I u~
~ ~ ,.
o'P O O d~
u~ ,
E~
~ '~a ~ Eo~ V,~ E EE,::::
u~ ~a~ a~ ~+
I .,, + O + + + ~ + . ~ .
. ~ ~ ~ U~
~ . ~ O
~8~5~4
-36-
C-I-L 711
EXAMPLE 7 - (Series G)
Runs 66 to 75 inclusive evaluated a hardwood furnish
with a filler comprising a blend of pigmented (rutile
titanium dioxide) vesiculated polymeric granules and
non-pigmented vesiculated polymeric granules with and
without retention aids. These eleven runs were prepared as
in the foregoing general procedure. The furnish
preparation, retention aid use, and order of material
addition were as those described in Example 2 except that
the filler used was a 1:1 weight ratio of pigmented
vesiculated polymeric granules and non-pigmented vesiculated
polymeric granules.
The results are shown in Table 7, also included are
runs 27, 29, 32, and 38 from Table 3 and runs 42, 44, 50 and
15 55 for ease of comparison of results. ~
-~7- ~Z8~)5~ C-I-L 711
~ ~ ~ ~ I~ ~ o ~ o U~ o
. . . ~
_
~ ~ l l l l l l l l l l l I
O ~
.~ ~ I l I I I I I I I~
o ~ _ .
~ ~ b l l l 1 1
~ ~; ... . . .
H ~1
1/1 --~
u~ I ~ _~ I In ~: : : In I
. ... _
/Y .~ ~ ~ I
~ . _ ~ : : : _ U~:::::
~ g)~ 'g
.__
~' I` ~ 0 ~ o ~ i o
~r ~D ~ ~r ~D ~D ~D 1` 1` ~ .n
. _ __ . _. .
3~ 1 ~8~)S4~ C-I-L 711
. _
~ o ~
5~ o~
~ oo
o ~
.~. ,
n
o~
_
I ~ I I
o _
~:
:~ ~ ~
H ~
E~ ~
U~ ~ l l l l l I
E'~
* dP ~
1~ 1~ I
O ~
~ ~ ~ ~* ~
C ~ ~ I : : _ :
~ i!~
,~'+
_
:~ ~ r ~
. . .
~280S4at
-39-
C-I-L 711
EXAMPLE 8 -- (Series H)
Runs 76 to 86 inclusive evaluated a hardwood furnish
with a filler comprising a pigmented (rutile titanium
dioxide) vesiculated polymeric granule with a median
diameter of 12 microns, with and without retention aids.
These eleven runs were made as in the foregoing general
procedure. The furnish preparation, retention aids used and
the order of material addition were as those described in
Example 2 except that the filler was an emulsion form of the
pigmented vesiculated polymeric granules.
The results are shown in Table 8. -
- - 4 - 1280544 c- -I. 7 1 1
H ~ I` ~ ~ ~10 C1~ 00 0 ~ l
& ~ x
~r x er
_ ~
o ~ I I 1 1,1 1 1 1~1 1
a
.~ ~ ~ r
:C o ~
~ ~ I I I 1 1~1 1 1 1 1
o~
~ ~ I I I lerl I I I I I
.~ ~ I I I I I I I I I I I
_
t ~ ~ I I I I I I I I I I I
CO ~
~ o 3~ dP
m ~
~ ~ ~ ,
i
~:: ::
+ ~.
g~ : : : : : : : : : :
~D oo a` X -i CC~ cO OD C~ 0
~Z80S4~
-41-
C-I-L 711
EXPERIMENT 9 -- (series I)
Runs 87 to 94 inclusive were performed with a hardwood
pulp, filler comprising pigmented (rutile titanium dioxide~
vesiculated polymeric granules of median particle size 12
microns and non-pigmented vesiculated polymeric granules of
median particle size of 5 microns, and retention aids.
These eight runs were made as in the foregoing general
procedure. The furnish preparation, retention aids used,
and the order of material addition were as the method
described in Example 2 except for the filler composition
which was an emulsion form of the pigmented and
non-pigmented vesiculated granules.
The results are shown in Table 9 including runs 76 and
78 from Table 8 and runs 9 and 11 from Table 2 for ease of
comparison.
-42- 1 ~8054~1 C-I-I. 7~ I
~; 1~ N ~ r ~ o
q ~) o tY~ ~I N N U~ _I ~) d '
~: ~ ~ ~ u~ In ~ ~ O~ 0~ 0 r o
dO I . _ _
. o ~ l I I I I I I 1_1 1
~ ~ I I I I I I I I I ~
c
H~) ~ 1 7 1 I I I I I ~
~ _
u7 ~ I I I I I I I ~ I I I I _
E l N ¦ ~ : : N IJ I
U~ ~ ~
~ ~ l l l l l l l l l l l I
,1 C ~
O ~'-
~_I ~ ~ ~d N It~ I Ltl: N 11~
~ l i
m ~ dP ~ N _1 111 I
~t I ~ I
I -
~ I` ~ a~ co oo o' _~ ~
- . . .
~ 280544
- 4 3--
C-I-L 711
EXPERIMENT 10 - (Series J)
Runs 95 to 102 inclusive were performed with a hardwood
pulp, filler comprising a blend of pigmented (rutile
titanium dioxide) vesiculated polymeric granules of median
5 particle size diameter of 12 microns and non-pigmented
vesiculated polymeric granules of median particle size of 5
microns, with and without the use of retention aids. These
eight runs were prepared as in the foregoing general
procedure. The furnish preparation, retention aid used, and
10 order of material addition were as those described in
Example 2 except that the filler used was a 1:1 weight ratio
blend of the pigmented and non-pigmented vesiculated
polymeric granule emulsions.
The results are shown in Table 10 including runs 76 and
15 78 from Table 8, runs 27 and 29 from Table 3 for ease of
comparison of results.
44- ~280~;44 C-I-L 711
cn Ln o~ r~ ~ o ~ ~D Ln
o o~ n Ln ~ u~
~r Ll~ ~ n .n ~r ~D Ln ~ Ln o
& ~ ~
_ ~
~ Ln 2 = ~ 2 ~ 2
~ F~ I I I I I ~ I I I 1~1
~ ~ I I I I I I I I I~
v r~ ~
~; ~ I I I I I I I I er I I I
H _ ~ I I t l I I I ~
t~n ~ ~1 11 111 11111
~ ~ 1~ H ~`~ I Ln I I ~ : : Ln
o ~
, l~g 1~ , ~ LdnP I n ,~ I ~: : : LdnP
~ ~ i ._ _ i
e ~ dP dnP :: ,~:: n::: _l
. ~ ~ l
j w ~D g ~ ~ g ~ ~
g
, ~
I . . .
Ln LD ~ 0 ~n o o o
,
~Z80~;44
-45-
C-I-L 711
Discussion of Tabulated Results
It can be seen from Table 1 - (Series A) that the use
of retention aids in combination with the fully bleached
S chemical hardwood kraft pulp, does not contribute to any
significant change in percent opacity. Thus, any gains in
opacity reported in the following series can be directly
attributed to interactions between the fillers, retention
aids and pulp. The decrease in opacity observed in
furnishes adjusted to neutral or alkaline conditions may be
attributed to small repulsive forces increasing as the level
of free negatively charged hydroxide ions was increased. In
the furnish, which is already anionic in nature, these
forces may decrease retention of the pulp flocs.
It can be seen from Table 2 (Series B) that at the 5%
filler level the maximum percent opacity obtained was with
the use of Alum as a retention aid (79.47%). It can also be
seen that pulp with anatase titanium dioxide, in the absence
of a retention aid, shows no significant change in % opacity
as the pH changes from acid to alkaline. The presence of
retention aids renders the pulp plus anatase titanium
dioxide furnish slightly more sensitive to changes in pH
when observing % opacity. The degree of difference is still
quit,e small.
It can be seen from Table 3 (Series C) that at the 5%
filler level the maximum percent opacity obtained was with
the use of the retention aid dimethylamine epichlorohydrin
(76.87). A further gain of 0.8% opacity was obtained when
the pH was increased from 4.5 to 8.5. At the 10% filler
level the maximum percent opacity was also obtained with the
use of the retention aid dimethylamine epichlorohydrin
(79.27).
It can also be seen from Table 3 that when the pH of
pulp with vesiculated granules was raised from 4.5 to 8.5 a
small decrease in % opacity was observed when the pH was
~Z80S44
-46-
C-I-L 711
raised in the furnish which contains the dimethylamine
epichlorohydrin, pulp, and vesiculated granules (runs 32 and
33) an increase % opacity was observed. Run number 35 which
demonstrated the effect of alkaline pH on a furnish
containing Alum was included as a known control. It is
known in the papermaking field that Alum is useful only in
acidic papermaking due to its chemical structure and ionic
nature. Run 35 demonstrated the expected drop in opacity of
Alum used in an alkaline furnish.
It can be seen from Table 4 - (Series D) that when
vesiculated polymeric granules and anatase titanium dïoxide
were combined to form a filler at acidic pH, an enhancement
of % opacity could be gained over the use of anatase
titanium dioxide alone as a filler. This feature was
observed for both 5 and 10 percent filler level on pulp.
It can be seen from Table 5 - (Series E) that % opacity
gains of a significant amount were obtained with the use of
pigmented vesiculated polymeric granules over anatase
titanium dioxide. Comparing the two fillers without the use
of retention aids at the 5% filler level on pulp (runs 42
and 9) a gain of 0.7 percent opacity was achieved. At the
10 percent filler level on pulp (runs 44 and 11) a gain of
0.4 percent opacity was achieved. With the use of retention
aids comparing 5 percent filler level on pulp, the anatase
titanium dioxide sample using Alum achieved 79.5 percent
opacity. This was compared to pigmented vesiculated
polymeric granules with dimethylamine epichlorohydrin as the
retention aid which achieved an opacity of 79.0 percent at
pH 4.5 or 81.04 percent at pH 6.5.
When the level of pigmented vesiculated polymeric
granules was increased to 10 percent on pulp weight and
incorporated the use of dimethylamine epichlorohydrin as the
retention aid an excellent opacity of 82.6 percent at pH 4.5
and 84.5 percent at pH 7.5 was achieved. This reflects a
gain of 10 percent opacity units over the use of pigmented
~.280544
-47-
C-I-L 711
vesiculated polymeric granules without the use of a
retention aid. This example illustrates the claims of this
invention.
It can be seen from Table 6 (Series F) that the maximum
percent opacity obtained in this Series (which is examining
the effect of combining titanium dioxide and pigmented
vesiculated granules together as a filler) was obtained when
the blend was used at a level of 10 percent on pulp weight
and incorporated the retention aid dimethylamine
epichlorohydrin (81.20~ opacity). Runs 9, 42 and 59 show
that at a 5% combined filler level the use of the pigmented
granules was better for percent opacity than titanium
dioxide alone. The blend of the two fillers gave a percent
opacity value that was between that for the fillers
separately. This effect was noticed at 5 and 10 percent
filler levels.
The excellent response of the filler blend to all four
retention aids demonstrated that where a particular
retention aid would enhance opacity for one of the fillers,
this enhancement was also observed in the blend of fillers.
It can be seen from Table 7 (Series G) that if the
filler comprises a blend of both pigmented and non-pigmented
vesiculated granules the percent opacity achieved was
generally higher than for non-pigmented vesiculated
polymeric granules as a single filler and slightly lower
than pigmented vesiculated polymeric granules as a single
filler. With the use of retention aids the blend of
non-pigmented and pigmented vesiculated polymeric granules
achieved percent opacities almost equal to the pigmented
granules. This could mean that a paper sheet prepared with
a properly tailored blend of pigmented and non-pigmented
vesiculated granules could achieve a target percent opacity
and have a corresponding reduction in weight and cost of the
paper sheet.
.
~Z80544
--48--
C-I--L 711
It can be seen from Table 8 (Series H) that the larger
median diameter (12 microns) pigmented vesiculated granules
have an improved ~ opacity gain over anatase titanium
dioxide and 5 micron diameter (median) pigmented vesiculated
granules when used as a filler. The retention aid
dimethylamine epichlorohydrin assisted in increasing the
percent opacity gain.
It can be seen from Table 9 (Series I) that the
blending of pigmented vesiculated polymeric granules (median
diameter 12 microns) and anatase titanium dioxide to form a
filler, did not give a significant increase in percent
opacity over the use of the granules alone. The best
retention aids for increased percent opacity were again
noted to be dimethylamine epichlorohydrin and alum. Each
retention aid contributing to the filler portion best suited
to its structure, the DMA-EPI was definitely aiding the
granules, and alum aiding the Tio2.
It can be seen from Table 10 (Series J) that the blend
of larger median diameter (25 microns) pigmented vesiculated
granules with non-pigmented vesiculated granules as a filler
for a paper sheet achieved better percent opacity than by
using non-pigmented granules only. The excellent increase
in percent opacity obtained with the use of the retention
aid dimethylamine epichlorohydrin could suggest that a paper
sheet prepared with a properly tailored blend of pigmented
and non-pigmented vesiculated polymeric granules could
achieve a targeted percent opacity and have a corresponding
reduction in weight and cost of the paper sheet.
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