Note: Descriptions are shown in the official language in which they were submitted.
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HYBRID EMULSION AGGREGATE TONER
BACKGROUND
[0001] The present disclosure relates to toners and processes useful in
providing toners
suitable for electrophotographic apparatuses, including apparatuses such as
digital, image-on-
image, and similar apparatuses. In particular, the disclosure relates to
emulsion aggregate toner
compositions that use two different emulsion aggregation (EA) technologies.
Namely, the
present embodiments provide an emulsion aggregation toner that comprises a
base resin
composed of both styrene-acrylate and polyester resins. These embodiments
comprise
polyaluminum chloride (PAC) instead of the more commonly used aluminum sulfate
as the
flocculant or aggregating agent. Toners made in this manner exhibit improved
surface
morphology and achieved improved toner blocking and percent hcat cohesion,
particularly for
black toner. Further, such hybrid emulsion aggregation toner compositions are
lower in cost but
still maintain desirable developer properties like low minimum fusing
temperature (MFT) and
lower dielectric loss.
[0002] Numerous processes are within the purview of those skilled in the
art for the
preparation of toners. Emulsion aggregation is one such method. These toners
are within the
purview of those skilled in the art and toners may be formed by aggregating a
colorant with a
latex polymer formed by emulsion polymerization. For example, U.S. Pat. No.
5,853,943 is
directed to a semi-continuous emulsion polymerization process for preparing a
latex by first
forming a seed polymer. Other examples of emulsion/aggregation/coalescing
processes for the
preparation of toners are illustrated in U.S. Pat. Nos. 5,403,693, 5,418,108,
5,364,729, and
5,346,797. Other processes are disclosed in U.S. Pat. Nos. 5,527,658,
5,585,215, 5,650,255,
5,650,256 and 5,501,935.
100031 Electrophotography, which is a method for visualizing image
information by
forming an electrostatic latent image, is currently employed in various
fields. The term
-electrostatographic" is generally used interchangeably with the term
"electrophotographic." In
general, electrophotography comprises the formation of an electrostatic latent
image on a
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photoreceptor, followed by development of the image with a developer
containing a toner, and
subsequent transfer of the image onto a transfer material such as paper or a
sheet, and fixing the
image on the transfer material by utilizing heat, a solvent, pressure and/or
the like to obtain a
permanent image.
[0004] Emulsion aggregation toners may comprise various resins for use in
forming the
latex. One type of emulsion aggregation toner provides high gloss and uses
styrene-acrylate, a
lower costing resin. Another type of emulsion aggregation toner provides
better fusing
performance (e.g., lower Minimum Fix Temperature (MFT) of about 20 C) and
uses polyesters
as the base resin. However, the polyester resins used are high in cost. Thus,
the present
embodiments seek to form a hybrid emulsion aggregation toner that combines the
advantages
from both types of toners. However, it was discovered that toners with styrene-
acrylate latexes
do not melt at the same temperature during the toner process as the polyester
toners, thus leading
to variation in the surface morphology in a hybrid of the two toner types
(more
polystyrene/acrylate remains on the surface). The present embodiments replace
some of the
polyester resin used in the core of the lower fusing toner with some of the
styrene-acrylate of the
high gloss toner and includes PAC as the aggregating agent. Such a hybrid
composition provides
a lower costing toner that retains good fusing performance and low dielectric
loss. Moreover,
the PAC unexpectedly improves the surface morphology by reducing the amount of
styrene-
acrylate on the surface.
SUMMARY
[0005] The present embodiments provide a toner composition a toner
composition
comprising: toner particles having a core, wherein the core comprises a resin,
a colorant, a wax,
and polyaluminum chloride, wherein the resin comprises a styrene-acrylate
resin, a crystalline
polyester resin and an amorphous polyester resin; and a shell disposed over
the core.
[0006] In specific embodiments, there is provided a toner composition a
developer
comprising: a toner composition; and a toner carrier, wherein the toner
composition comprises
toner particles having a core, wherein the core comprises a resin, a colorant,
a wax, and
polyaluminum chloride, wherein the resin comprises a styrene-acrylate resin, a
crystalline
polyester resin and an amorphous polyester resin; and a shell disposed over
the core.
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[0007] In yet other embodiments, there is provided a developer comprising a
method of
making a toner comprising mixing together and emulsifying a resin, a colorant,
and a wax,
wherein the resin comprises a styrene-acrylate resin, a crystalline polyester
resin to form a latex
emulsion; adding polyaluminum chloride to the latex emulsion; aggregating the
latex emulsion to
form toner particle cores, wherein the toner particle cores comprise the
styrene-acrylate resin, the
crystalline polyester resin and the amorphous polyester; forming a shell over
the toner particle
cores to form toner particles; coalescing the toner particles; and cooling the
toner particles.
10007a1 In accordance with an aspect, there is provided a toner composition
comprising:
toner particles having a core, wherein the core comprises
a resin,
a colorant,
a wax, and
polyaluminum chloride in an amount of from about 0.1 to about 1.0
percent by weight of the total weight of the toner particles, wherein the
resin
comprises a styrene-acrylate resin present in the core in an amount of from
about
to about 35 percent by weight of the total weight of the core, a crystalline
polyester resin present in the core in an amount of from about 3 to about 10
percent by wcight of the total weight of the core and an amorphous polyester
resin
present in the core in an amount of from about 20 to about 30 percent by
weight
of the total weight of the core; and
a shell disposed over the core, further wherein an emulsion of the styrene-
acrylate
resin used in the core has a particle size of from about 100 nm to about 141
nm.
10007b1 In accordance with an aspect, there is provided a developer
comprising:
a toner composition; and
a toner carrier, wherein the toner composition comprises
toner particles having a core, wherein the core comprises
a resin,
a colorant,
a wax, and
polyaluminum chloride in an amount of from about 0.1 to about 1.0
percent by weight of the total weight of the toner particles, wherein the
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resin comprises a styrene-acrylate resin present in the core in an amount of
from about 10 to about 35 percent by weight of the total weight of the
core, a crystalline polyester resin present in the core in an amount of from
about 3 to about 10 percent by weight of the total weight of the core and
an amorphous polyester resin present in the core in an amount of from
about 20 to about 30 percent by weight of the total weight of the core; and
a shell disposed over the core, further wherein an emulsion of the styrene-
acrylate resin used in the core has a particle size of from about 100 nm to
about
141 nm.
[00070 In accordance with an aspect, there is provided a method of making a
toner
comprising
mixing together and emulsifying a resin, a colorant, and a wax, wherein the
resin
comprises a styrene-aerylate resin, a crystalline polyester resin and an
amorphous
polyester resin to form a latex emulsion, wherein an emulsion of the styrene-
acrylate
resin has a particle size of from about 100 nm to about 141 nm;
adding polyaluminum chloride to the latex emulsion;
aggregating the latex emulsion to form toner particle cores, wherein the toner
particle cores comprise the styrene-acrylate resin present in the core in an
amount of from
about 10 to about 35 percent by weight of the total weight of the core, the
crystalline
polyester resin present in the core in an amount of from about 3 to about 10
percent by
weight of the total weight of the core and the amorphous polyester resin
present in the
core in an amount of from about 20 to about 30 percent by weight of the total
weight of
the core;
forming a shell over the toner particle cores to form toner particles;
coalescing the toner particles; and
cooling the toner particles;
wherein the polyaluminum chloride is added to the latex emulsion in an amount
of from about 0.1 parts per hundred to about 1 parts per hundred of the toner
particles.
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BRIEF DESCRIPTION OF THE DRAWINGS
100081 For a better understanding of the present embodiments, reference may
be had to the
accompanying figures.
[0009] Figure 1 A provides scanning electron microscope (SEM) images of
comparative
polyester-based toner particles;
[0010] Figure 1I3 provides SEM images of a hybrid toner made according to
the present
embodiments;
100111 Figure 1C provides SEM images of another hybrid toner made according
to the
present embodiments; and
[0012] Figure 2 is a graph illustrating the improved % heat cohesion of the
toner made
according to the present embodiments as compared to control toners.
DETAILED DESCRIPTION
[0013] As discussed above, the present embodiments provide a hybrid
emulsion
aggregation (EA) toner where a conventionally polyester particle core is
replaced with a portion
of styrene-acrylate resin. Thus, the novel toner composition has styrene
acrylate in the core as
well as crystalline and amorphous polyester resins in the core. These resins
are used to form the
latex emulsion and ultimately get incorporated into the resulting particle
core. The toner particle
shell comprises polyester resin, and specifically, crystalline polyester
resin. The styrene-acrylate
resin is a lower costing resin as compared to the polyester resin used and
thus reduces the overall
cost of producing the toner while still achieving good fusing performance,
dielectric loss,
charging, blocking and percent cohesion. In addition, the present toner
embodiments include
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polyaluminum chloride (PAC) as the aggregating agent. It was discovered that
the PAC
unexpectedly improves the surface morphology by reducing the amount of styrene-
acrylate on
the surface.
[0014] In embodiments, the styrene-acrylate resin is present in the toner
particle core in an
amount of from about 5 to about 35, or from about 10 to about 35, or from
about 20 to about 35
percent by weight of the total weight of the core. In embodiments, the
particle size of the
styrene-acrylate emulsion is from about 100 nm to about 160 nm, or from about
100 run to about
140 nm. It was discovered that use of styrene-acrylate resin in this range
together with PAC
provided optimum results in EA toner with good performance and properties and
improved
surface morphology.
[0015] In embodiments, the resins may be a polyester resin. such as, an
amorphous resin, a
crystalline resin, and/or a combination thereof, including the resins
described in U.S. Patent Nos.
6,593,049 and 6,756,176. Suitable resins may also include a mixture of an
amorphous polyester
resin and a crystalline polyester resin as described in U.S. Patent No.
6,830,860.
[0016] In embodiments, the crystalline polyester resins is present in the
toner particle core
in an amount of from about 1 to about 20 , or from about 1 to about 15, or
from about 3 to about
percent by weight of the total weight of the core. In embodiments, the
crystalline polyester
resin used in the core is selected from the group consisting of poly(ethylene-
adipate),
poly(propylene-adipate), poly(butylene-adipate), poly(pentylene-adipate),
poly(hexylene-
adipate), poly(octylene-adipate), poly(ethylene-succinate), poly(propylene-
succinate),
poly(butylene-succinate), poly(pentylene-succinate), poly(hexylene-succinate),
poly(octylene-
succinate), poly(ethylene-sebacate), poly(propylene-sebacate), poly(butylene-
sebacate),
poly(pentylene-sebacate), poly(hexylene-sebacate), poly(octylene-sebacate),
poly(decylene-
sebacate), poly(decylene-decanoate), poly(ethylene-decanoate), poly(ethylene
dodecanoate),
poly(nonylene-sebacate), poly(nonylene-decanoate), copoly(ethylene-fumarate)-
copoly(ethylene-sebacate), copoly(ethylene-fumarate)-copoly(ethylene-
decanoate),
copoly(ethylene-fumarate)-copoly(ethylene-dodecanoate) to further reduce cost.
Preferred low
cost crystalline polyesters are poly(1.9-nonylene-1,12-dodecanoate), poly(1,6-
hexylene-1,12-
dodecanoate) and poly(1,6-hexylene-1,10-decanoate).
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[0017] In embodiments, the amorphous polyester resin is present in the
toner particle core
in an amount of from about 20 to about 80, or from about 20 to about 70, or
from about 30 to
about 65 percent by weight of the total weight of the core. Such amorphous
polyester resins are
selected from the group consisting of poly(alkoxylated bisphenol-A co-fumarate
¨
coterephthalate-cododecenylsuccinate), and mixtures thereof. In embodiments,
as noted above,
an unsaturated amorphous polyester resin may be utilized as a latex resin. In
embodiments
embodiment, the amorphous polyester resin can be obtained from Kao corporation
as FXC42 and
FXC56. Examples of such resins include those disclosed in U.S. Patent No.
6,063,827 and No.
8,466,254. Exemplary unsaturated amorphous polyester resins include, but are
not limited to,
poly(propoxylated bisphenol co-fumarate), poly(ethoxylated bisphenol co-
fumarate),
poly(butyloxylated bisphenol co-fumarate), poly(co-propoxylated bisphenol co-
ethoxylated
bisphenol co-fumarate), poly(1,2-propylene fumarate), poly(propoxylated
bisphenol co-maleate),
poly(ethoxylated bisphenol co-maleate), poly(butyloxylated bisphenol co-
maleate), poly(co-
propoxylated bisphenol co-cthoxylated bisphenol co-maleate), poly(1,2-
propylene maleate),
poly(propoxylated bisphenol co-itaconate), poly(ethoxylated bisphenol co-
itaconate),
poly(butyloxylated bisphenol co-itaconate), poly(co-propoxylated bisphenol co-
ethoxylated
bisphenol co-itaconate), poly(1,2-propylene itaconate), poly(co-propoxylated
bisphenol co-
ethoxylated bisphenol co-fumarate-coterephthalate-co-dodecenysuccinate) and
combinations
thereof.
[0018] The emulsion aggregation toner of the present embodiments has a
minimum fusing
temperature (MFT) of from about 90 to about 150, or from about 100 to about
130, or from about
100 to about 125. This is about from about 15 to about 20 lower than other
emulsion
aggregation toners without polyester in the core or shell. The present
embodiments also have
acceptable dielectric loss of from about 10 to about 40, or from about 20 to
about 40, or from
about 20 to about 35. From previous studies, the present inventors discovered
that the dielectric
loss of toners can be improved by increased shell thickness and decreasing the
coalescence
temperature. As such, the present toner composition has a preferable shell
percentage of from
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about 28 to about 40, or from about 30 to about 38, or from about 30 to about
36 percent of the
toner particles. In making these toner compositions, the coalescence
temperature used is
preferably of from about 70 to about 90 C, or from about 70 to about 80 C, or
from about 70 to
about 77 C. In particular embodiments, the latex particle size used in making
these toner
compositions is of from about 100 nm to 159 nm. The present inventors also
discovered that
lowering the coalescence temperature and using smaller latex particle sizes
help prevent any
phase separation of the styrene-acrylate resin from the polyester resins and
keep the styrene-
acrylate in the core rather than migrating to the surface. In this manner,
good electrical and
fusing properties are maintained.
[0019] Latex Resin
[0020] In embodiments, a developer is disclosed including a resin coated
carrier and a
toner, where the toner may be an emulsion aggregation toner, containing, but
not limited to, a
latex resin, a wax and a polymer shell.
[0021] Generally, the latex resin may be composed of a first and a second
monomer
composition. Any suitable monomer or mixture of monomers may be selected to
prepare the
first monomer composition and the second monomer composition. The selection of
monomer or
mixture of monomers for the first monomer composition is independent of that
for the second
monomer composition and vice versa. In case a mixture of monomers is used,
typically the latex
polymer will be a copolymer. As discussed above, the latex resin is composed
of at least styrene
acrylate, a polyester resin and a crystalline resin.
[0022] Exemplary monomers for the first and/or the second monomer
compositions
include, but are not limited to, polyesters, styrene, alkyl acrylate, such as,
methyl acrylate, ethyl
acrylate, butyl arylate, isobutyl acrylate, dodecyl acrylate, n-octyl
acrylate, 2-chloroethyl
acrylate; 0-carboxy ethyl acrylate (13-CEA), phenyl acrylate, methyl
alphachloroacrylate, methyl
methacrylate, ethyl methacrylate and butyl methacrylate; butadiene; isoprene;
methacrylonitrile;
acrylonitrile; vinyl ethers, such as, vinyl methyl ether, vinyl isobutyl
ether, vinyl ethyl ether and
the like; vinyl esters, such as, vinyl acetate, vinyl propionate, vinyl
benzoate and vinyl butyrate;
vinyl ketones, such as, vinyl methyl ketone, vinyl hexyl ketone and methyl
isopropenyl ketone;
vinylidene halides, such as, vinylidene chloride and vinylidene
chlorofluoride; N-vinyl indole;
N-vinyl pyrrolidone; methacrylate; acrylic acid; methacrylic acid; acrylamide;
methacrylamide;
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vinylpyridine; vinylpyrrolidone; vinyl-N-methylpyridinium chloride; vinyl
naphthalene; p-
chlorostyrene; vinyl chloride; vinyl bromide; vinyl fluoride; ethylene;
propylene; butylenes;
isobutylene; and the like, and mixtures thereof,
[0023] In some embodiments, the first monomer composition and the second
monomer
composition may independently of each other comprise two or three or more
different
monomers. The latex polymer therefore can comprise a copolymer. Illustrative
examples of such
a latex copolymer includes poly(styrene-n-butyl acrylate-P-CEA), poly(styrene-
alkyl acrylate),
poly(styrene-1,3-diene), poly(styrene-alkyl methacrylate), poly(alkyl
methacrylate-alkyl
acrylate), poly(alkyl methacrylate-aryl acrylate), poly(aryl methacrylate-
alkyl acrylate),
poly(alkyl methacrylate), poly(styrene-alkyl acrylate-acrylonitrile),
poly(styrene-1,3-diene-
acrylonitrile), poly(alkyl acrylatc-acrylonitrile), poly(styrene-butadiene),
poly(methylstyrene-
butadiene), poly(methyl methacrylate-butadiene), poly(ethyl methacrylate-
butadiene),
poly(propyl methacrylate-butadiene), poly(butyl methacrylate-butadiene),
poly(methyl acrylate-
butadiene), poly(ethyl acrylate-butadiene), poly(propyl acrylate-butadiene),
poly(butyl acrylate-
butadiene), poly(styrene-isoprene), poly(methylstyrene-isoprene), poly(methyl
methacrylate-
isoprene), poly(ethyl methacrylate-isoprene), poly(propyl methacrylate-
isoprene), poly(butyl
methacrylate-isoprene), poly(methyl acrylate-isoprene), poly(ethyl acrylate-
isoprene),
poly(propyl acrylate-isoprcnc), poly(butyl acrylate-isoprene); poly(styrene-
propyl acrylate),
poly(styrene-butyl acrylate), poly(styrene-butadiene-acrylonitrile),
poly(styrene-butyl acrylate-
acrylononitrile), and the like.
[0024] In embodiments, the first monomer composition and the second monomer
composition may be substantially water insoluble, such as, hydrophobic, and
may be dispersed in
an aqueous phase with adequate stirring when added to a reaction vessel.
[0025] The weight ratio between the first monomer composition and the
second monomer
composition may be in the range of from about 0.1:99.9 to about 50:50,
including from about
0.5:99.5 to about 25:75, from about 1:99 to about 10:90.
[0026] In embodiments, the first monomer composition and the second monomer
composition can be the same. Examples of the first/second monomer composition
may be a
mixture comprising styrene and alkyl acrylate, such as, a mixture comprising
styrene, n-butyl
acrylate and P-CEA. Based on total weight of the monomers, styrene may be
present in an
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amount from about 1% to about 99%, from about 50% to about 95%, from about 70%
to about
90%, although may be present in greater or lesser amounts; alkyl acrylate,
such as, n-butyl
acrylate, may be present in an amount from about 1% to about 99%, from about
5% to about
50%, from about 10% to about 30%, although may be present in greater or lesser
amounts.
[0027] In embodiments, the resin may be a polyester resin formed by
reacting a diol with a
diacid in the presence of an optional catalyst. For forming a crystalline
polyester, suitable
organic diols include aliphatic diols with from about 2 to about 36 carbon
atoms, such as 1,2-
ethanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol,
1,7-heptanediol,
1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol and the
like. The aliphatic
diol may be, for example, selected in an amount of from about 40 to about 60
mole percent, in
embodiments from about 42 to about 55 mole percent, in embodiments from about
45 to about
53 mole percent (although amounts outside of these ranges can be used).
[0028] Examples of organic diacids or diesters including vinyl diacids or
vinyl diesters
selected for the preparation of the crystalline resins include oxalic acid,
succinic acid, glutaric
acid, adipic acid, suberic acid, azelaic acid, sebacic acid, 1,12-dodecanoic
acid, fumaric acid,
dimethyl fumarate, dimethyl itaconate, cis, 1,4-diacetoxy-2-butene, diethyl
fumarate, diethyl
maleate, phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-
dicarboxylic acid,
naphthalene-2,7-dicarboxylic acid, cyclohexane dicarboxylic acid, malonic acid
and mesaconic
acid, a diester or anhydride thereof. The organic diacid may be selected in an
amount of, for
example, in embodiments from about 40 to about 60 mole percent, in embodiments
from about
42 to about 52 mole percent, in embodiments from about 45 to about 50 mole
percent.
[0029] The crystalline resin can possess various melting points of, for
example, from about
30 C to about 120 C, in embodiments from about 50 C to about 90 C. The
crystalline resin
may have a number average molecular weight (Mn), as measured by gel permeation
chromatography (GPC) of, for example, from about 1,000 to about 50,000, in
embodiments from
about 2,000 to about 25,000, and a weight average molecular weight (K) of, for
example, from
about 2,000 to about 100,000, in embodiments from about 3,000 to about 80,000,
as determined
by Gel Permeation Chromatography using polystyrene standards. The molecular
weight
distribution (Mw/Mn) of the crystalline resin may be, for example, from about
2 to about 6, in
embodiments from about 3 to about 4.
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[0030] Examples of diacids or diesters including vinyl diacids or vinyl
diesters utilized for
the preparation of amorphous polyesters include dicarboxylic acids or diesters
such as
terephthalic acid, phthalic acid, isophthalic acid, fumaric acid, dimethyl
fumarate, dimethyl
itaconate, cis, 1,4-diacetoxy-2-butene, diethyl fumarate, diethyl maleate,
maleic acid, succinic
acid, itaconic acid, succinic acid, succinic anhydride, dodecylsuccinic acid,
dodecylsuccinic
anhydride, glutaric acid, glutaric anhydride, adipic acid, pimelic acid,
suberic acid, azelaic acid,
dodecane diacid, dimethyl terephthalate, diethyl terephthalate,
dimethylisophthalate,
diethylisophthalate, dimethylphthalate, phthalic anhydride, diethylphthalate,
dimethylsuccinate,
dimethylfumarate, dimethylmaleate, dimethylglutarate, dimethyladipate,
dimethyl
dodecylsuccinate, and combinations thereof. The organic diacid or diester may
be present, for
example, in an amount from about 40 to about 60 mole percent of the resin, in
embodiments
from about 42 to about 52 mole percent of the resin, in embodiments from about
45 to about 50
mole percent of the resin. Examples of the alkylene oxide adducts of bisphenol
include
polyoxypropylene (2.2)-2,2-bis(4-hydroxyphenyl) propane, polyoxypropylene
(3.3)-2,2-bis(4-
hydroxyphenyl) propane, polyoxyethylene (2.0)-2,2-bis(4-hydroxyphenyl)
propane,
polyoxyethylene (2.2)-2,2-bis(4-hydroxyphenyl) propane, polyoxypropylene (2.0)-
polyoxyethylene (2.0)-2,2-bis(4-hydroxyphenyl) propane, and polyoxypropylene
(6)-2,2-bis(4-
hydroxyphenyl) propane. These compounds may be used singly or as a combination
of two or
more thereof
[0031] Examples of additional diols which may be utilized in generating the
amorphous
polyester include 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-
butanediol, 1,4-
butanediol, pentanediol, hexanediol, 2,2-dimethylpropanediol, 2,2,3-
trimethylhexanediol,
heptanediol, dodecanediol, 1,4-cyclohexanedimethanol, 1,3-
cyclohexanedimethanol,
xylenedimethanol, cyclohexanediol, diethylene glycol, dipropylene glycol,
dibutylene, and
combinations thereof The amount of organic diol selected can vary, and may be
present, for
example, in an amount from about 40 to about 60 mole percent of the resin, in
embodiments
from about 42 to about 55 mole percent of the resin, in embodiments from about
45 to about 53
mole percent of the resin.
[0032] Polycondensation catalysts which may be utilized in forming either
the crystalline
or amorphous polyesters include tetraalkyl titanates, dialkyltin oxides such
as dibutyltin oxide,
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tetraalkyltins such as dibutyltin dilaurate, and dialkyltin oxide hydroxides
such as butyltin oxide
hydroxide, aluminum alkoxides, alkyl zinc, dialkyl zinc, zinc oxide, stannous
oxide, or
combinations thereof. Such catalysts may be utilized in amounts of, for
example, from about
0.01 mole percent to about 5 mole percent based on the starting diacid or
diester used to generate
the polyester resin.
[0033] Furthermore, in embodiments, a crystalline polyester resin may be
contained in the
binding resin. The crystalline polyester resin may be synthesized from an acid
(dicarboxylic
acid) component and an alcohol (diol) component. In what follows, an "acid-
derived component"
indicates a constituent moiety that was originally an acid component before
the synthesis of a
polyester resin and an "alcohol-derived component" indicates a constituent
moiety that was
originally an alcoholic component before the synthesis of the polyester resin.
[0034] A "crystalline polyester resin" indicates one that shows not a
stepwise endothermic
amount variation but a clear endothermic peak in differential scanning
calorimetry (DSC).
However, a polymer obtained by copolymerizing the crystalline polyester main
chain and at least
one other component is also called a crystalline polyester if the amount of
the other component is
50% by weight or less.
[0035] As the acid-derived component, an aliphatic dicarboxylic acid may be
utilized, such
as a straight chain carboxylic acid. Examples of straight chain carboxylic
acids include oxalic
acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid,
suberic acid, azelaic
acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid,
1,1-
undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,13-
tridecanedicarboxylic acid,
1,14-tetradecanedicarboxylic acid, 1,16-hexadecanedicarboxylic acid, and 1,18-
octadecanedicarboxylic acid, as well as lower alkyl esters and acid anhydrides
thereof. Among
these, acids having 6 to 10 carbon atoms may be desirable for obtaining
suitable crystal melting
point and charging properties. In order to improve the crystallinity, the
straight chain carboxylic
acid may be present in an amount of about 95% by mole or more of the acid
component and, in
embodiments, more than about 98% by mole of the acid component. Other acids
are not
particularly restricted, and examples thereof include conventionally known
divalent carboxylic
acids and dihydric alcohols, for example those described in "Polymer Data
Handbook: Basic
Edition" (Soc. Polymer Science, Japan Ed.: Baihukan). Specific examples of the
monomer
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PATENT APPLICATION
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components include, as divalent carboxylic acids, dibasic acids such as
phthalic acid, isophthalic
acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-
dicarboxylic acid,
and cyclohexanedicarboxylic acid, and anhydrides and lower alkyl esters
thereof, as well as
combinations thereof, and the like.
[0036] As the alcohol component, aliphatic dialcohols may be used. Examples
thereof
include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-
hexanediol, 1,7-
heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-
dodecanediol, 1,12-
undecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol
and 1,20-
eicosanediol. Among them, those having from about 6 to about 10 carbon atoms
may be used to
obtain desirable crystal melting points and charging properties. In order to
raise crystallinity, it
may be useful to use the straight chain dialcohols in an amount of about 95%
by mole or more, in
embodiments about 98% by mole or more.
[0037] Examples of other dihydric dialcohols which may be utilized include
bisphenol A,
hydrogenated bisphenol A, bisphenol A ethylene oxide adduct, bisphenol A
propylene oxide
adduct, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, diethylene glycol,
propylene glycol,
dipropylene glycol, 1,3-butanediol, neopentyl glycol, combinations thereof,
and the like.
[0038] For adjusting the acid number and hydroxyl number, the following may
be used:
monovalent acids such as acetic acid and benzoic acid; monohydric alcohols
such as
cyclohexanol and benzyl alcohol; benzenetricarboxylic acid,
naphthalenetricarboxylic acid, and
anhydrides and lower alkylesters thereof; trivalent alcohols such as glycerin,
trimethylolethane,
trimethylolpropane, pentaerythritol, combinations thereof, and the like.
[0039] The crystalline polyester resins may be synthesized from a
combination of
components selected from the above-mentioned monomer components, by using
conventional
known methods. Exemplary methods include the ester exchange method and the
direct
polycondensation method, which may be used singularly or in a combination
thereof. The molar
ratio (acid component/alcohol component) when the acid component and alcohol
component are
reacted, may vary depending on the reaction conditions. The molar ratio is
usually about 1/1 in
direct polycondensation. In the ester exchange method, a monomer such as
ethylene glycol,
neopentyl glycol or cyclohexanedimethanol, which may be distilled away under
vacuum, may be
used in excess.
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[0040] Surfactants
[0041] Any suitable surfactants may be used for the preparation of the
latex and wax
dispersions according to the present disclosure. Depending on the emulsion
system, any desired
nonionic or ionic surfactant such as anionic or cationic surfactant may be
contemplated.
[0042] Examples of suitable anionic surfactants include, but are not
limited to, sodium
dodecylsulfate, sodium dodecylbenzene sulfonate, sodium
dodecylnaphthalenesulfate, dialkyl
benzenealkyl sulfates and sulfonates, abitic acid, NEOGEN R and NEOGEN SC
available
from Kao, Tay-ca Power , available from Tayca Corp., DOWFAX , available from
Dow
Chemical Co., and the like, as well as mixtures thereof Anionic surfactants
may be employed in
any desired or effective amount, for example, at least about 0.01% by weight
of total monomers
used to prepare the latex polymer, at least about 0.1% by weight of total
monomers used to
prepare the latex polymer; and no more than about 10% by weight of total
monomers used to
prepare the latex polymer, no more than about 5% by weight of total monomers
used to prepare
the latex polymer, although the amount can be outside of those ranges.
[0043] Examples of suitable cationic surfactants include, but are not
limited to, dialkyl
benzenealkyl ammonium chloride, lauryl trimethyl ammonium chloride,
alkylbenzyl methyl
ammonium chloride, alkyl benzyl dimethyl ammonium bromide, benzalkonium
chloride, cetyl
pyridinium bromide, C12, C15 and C17 trimethyl ammonium bromides, halide salts
of quaternized
polyoxyethylalkylamines, dodecylbenzyl triethyl ammonium chloride, MIRAPOL
and
ALKAQUAT (available from Alkaril Chemical Company), SANIZOL (benzalkonium
chloride, available from Kao Chemicals), and the like, as well as mixtures
thereof.
[0044] Examples of suitable nonionic surfactants include, but are not
limited to, polyvinyl
alcohol, polyacrylic acid, methalose, methyl cellulose, ethyl cellulose,
propyl cellulose, hydroxy
ethyl cellulose, carboxy methyl cellulose, polyoxyethylene cetyl ether,
polyoxyethylene lauryl
ether, polyoxyethylene octyl ether, polyoxyethylene octylphenyl ether,
polyoxyethylene oleyl
ether, polyoxyethylene sorbitan monolaurate, polyoxyethylene stearyl ether,
polyoxyethylene
nonylphenyl ether, dialkylphenoxypoly(ethyleneoxy)ethanol (available from
Rhone-Poulenc as
IGEPAL CA-210 , IGEPAL CA-520 , IGEPAL CA-720 , IGEPAL CO-890 , IGEPAL CO-
720 , IGEPAL CO-290 , IGEPAL CA-210*, ANTAROX 8908, and ANTAROX 897 ) and the
like, as well as mixtures thereof
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[0045] Initiators
[0046] Any suitable initiator or mixture of initiators may be selected
in the latex process
and the toner process. In embodiments, the initiator is selected from known
free radical
polymerization initiators. The free radical initiator can be any free radical
polymerization
initiator capable of initiating a free radical polymerization process and
mixtures thereof, such
free radical initiator being capable of providing free radical species on
heating to above about
30 C.
[0047] Although water soluble free radical initiators are used in
emulsion polymerization
reactions, other free radical initiators also can be used. Examples of
suitable free radical
initiators include, but are not limited to, peroxides, such as, ammonium
persulfate, hydrogen
peroxide, acetyl peroxide, cumyl peroxide, tert-butyl peroxide, propionyl
peroxide, benzoyl
peroxide, chlorobenzoyl peroxide, dichlorobenzoyl peroxide, bromomethylbenzoyl
peroxide,
lauroyl peroxide, diisopropyl peroxycarbonate, tetralin hydroperoxide, 1-
pheny1-2-methylpropyl-
1-hydroperoxide and tert-butylhydroperoxide; pertriphenylacetate, tert-butyl
performate; tert-
butyl peracetate; tert-butyl perbenzoate; tert-butyl perphenylacetate; tert-
butyl
permethoxyacetate; tert-butyl per-N-(3-toluyl)carbamate; sodium persulfate;
potassium
persulfate, azo compounds, such as, 2,2'-azobispropane, 2,2'-dichloro-2,2'-
azobispropane, 1,11-
azo(methylethyl)diacetate, 2,2'-azobis(2-amidinopropane)hydrochloride, 2,2'-
azobis(2-
amidinopropane)-nitrate, 2,2'-azobisisobutane, 2,2'-azobisisobutylamide, 2,2'-
azobisisobutyronitrile, methyl 2,2'-azobis-2-methylpropionate, 2,2'-dichloro-
2,2'-azobisbutane,
2,2'-azobis-2-methylbutyronitrile, dimethyl 2,2'-azobisisobutyrate, 1,1'-
azobis(sodium 1-
methylbutyronitrile-3-sulfonate), 2-(4-methylphenylazo)-2-methylmalonod-
initrile, 4,4'-azobis-
4-cyanovaleric acid, 3,5-dihydroxymethylphenylazo-2-methylmalonodinitrile, 2-
(4-
bromophenylazo)-2-allylmalonodinitrile, 2,2'-azobis-2-methylvaleronitrile,
dimethyl 4,4'-azobis-
4-cyanovalerate, 2,2'-azobis-2,4-dimethylvaleronitrile, 1,1'-
azobiscyclohexanenitrile, 2,2'-azobis-
2-propylbutyronitrile, 1,1'-azobis-1-chlorophenylethane, 1,1'-azobis-1-
cyclohexanecarbonitrile,
1,1'-azobis-1-cycloheptanenitrile, 1,1'-azobis-1-phenylethane, 1,1'-
azobiscumene, ethyl 4-
nitrophenylazobenzylcyanoacetate, phenylazodiphenylmethane,
phenylazotriphenylmethane, 4-
nitrophenylazotriphenylmethane, 1'-azobis-1,2-diphenylethane, poly(bisphenol A-
4,4'-azobis-4-
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cyanopentano-ate) and poly(tetraethylene glycol-2,2'-azobisisobutyrate); 1,4-
bis(pentaethylene)-
2-tetrazene; 1,4-dimethoxycarbony1-1,4-dipheny-1-2-tetrazene and the like; and
mixtures thereof.
[0048] More typical free radical initiators include, but are not limited
to, ammonium
persulfate, hydrogen peroxide, acetyl peroxide, cumyl peroxide, tert-butyl
peroxide, propionyl
peroxide, benzoyl peroxide, chlorobenzoyl peroxide, dichlorobenzoyl peroxide,
bromomethylbenzoyl peroxide, lauroyl peroxide, sodium persulfate, potassium
persulfate,
diisopropyl peroxycarbonate and the like.
[0049] Based on total weight of the monomers to be polymerized, the
initiator may be
present in an amount from about 0.1% to about 5%, from about 0.4% to about 4%,
from about
0.5% to about 3%, although may be present in greater or lesser amounts.
[0050] A chain transfer agent optionally may be used to control the
polymerization degree
of the latex, and thereby control the molecular weight and molecular weight
distribution of the
product latexes of the latex process and/or the toner process according to the
present disclosure.
As can be appreciated, a chain transfer agent can become part of the latex
polymer.
[0051] Chain Transfer Agent
100521 In embodiments, the chain transfer agent has a carbon-sulfur
covalent bond. The
carbon-sulfur covalent bond has an absorption peak in a wave number region
ranging from 500
to 800cmd in an infrared absorption spectrum. When the chain transfer agent is
incorporated
into the latex and the toner made from the latex, the absorption peak may be
changed, for
example, to a wave number region of 400 to 4,000cm-l.
[0053] Exemplary chain transfer agents include, but are not limited to, n-
C3-15
alkylmercaptans, such as, n-propylmercaptan, n-butylmercaptan, n-
amylmercaptan,
n-hexylmercaptan, n-heptylmercaptan, n-octylmercaptan, n-nonylmercaptan, n-
decylmercaptan
and n-dodecylmercaptan; branched alkylmercaptans, such as, isopropylmercaptan,
isobutylmercaptan, s-butylmercaptan, tert-butylmercaptan, cyclohexylmercaptan,
tert-
hexadecylmercaptan, tert-laurylmercaptan, tert-nonylmercaptan, tert-
octylmercaptan and tert-
tetradecylmercaptan; aromatic ring-containing mercaptans, such as,
allylmercaptan, 3-
phenylpropylmercaptan, phenylmercaptan and mercaptotriphenylmethane; and so
on. The terms,
mercaptan and thiol may be used interchangeably to mean C-SH group.
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[0054] Examples of such chain transfer agents also include, but are not
limited to,
dodecanethiol, butanethiol, isoocty1-3-mercaptopropionate, 2-methyl-5-t-butyl-
thiophenol,
carbon tetrachloride, carbon tetrabromide and the like.
[0055] Based on total weight of the monomers to be polymerized, the chain
transfer agent
may be present in an amount from about 0.1% to about 7%, from about 0.5% to
about 6%, from
about 1.0% to about 5%, although may be present in greater or lesser amounts.
[0056] In embodiments, a branching agent optionally may be included in the
first/second
monomer composition to control the branching structure of the target latex.
Exemplary
branching agents include, but are not limited to, decanediol diacrylate
(ADOD),
trimethylolpropane, pentaerythritol, trimellitic acid, pyromellitic acid and
mixtures thereof.
[0057] Based on total weight of the monomers to be polymerized, the
branching agent may
be present in an amount from about 0% to about 2%, from about 0.05% to about
1.0%, from
about 0.1% to about 0.8%, although may be present in greater or lesser
amounts.
[0058] In the latex process and toner process of the disclosure,
emulsification may be done
by any suitable process, such as, mixing at elevated temperature. For example,
the emulsion
mixture may be mixed in a homogenizer set at about 200 to about 400rpm and at
a temperature
of from about 40 C to about 80 C for a period of from about lmin to about
20min.
[0059] Any type of reactor may be used without restriction. The reactor can
include means
for stirring the compositions therein, such as, an impeller. A reactor can
include at least one
impeller. For forming the latex and/or toner, the reactor can be operated
throughout the process
such that the impellers can operate at an effective mixing rate of about 10 to
about 1,00Orpm.
[0060] Following completion of the monomer addition, the latex may be
permitted to
stabilize by maintaining the conditions for a period of time, for example for
about 10 to about
300min, before cooling. Optionally, the latex formed by the above process may
be isolated by
standard methods known in the art, for example, coagulation, dissolution and
precipitation,
filtering, washing, drying or the like.
[0061] The latex of the present disclosure may be selected for emulsion-
aggregation-
coalescence processes for forming toners, inks and developers by known
methods. The latex of
the present disclosure may be melt blended or otherwise mixed with various
toner ingredients,
such as, a wax dispersion, a coagulant, an optional silica, an optional charge
enhancing additive
CA 02867713 2016-07-21
or charge control additive, an optional surfactant, an optional emulsifier, an
optional flow
additive and the like. Optionally, the latex (e.g. around 40% solids) may be
diluted to the desired
solids loading (e.g. about 12 to about 15% by weight solids), before
formulated in a toner
composition.
[0062] Based on the total toner weight, the latex may be present in an
amount from about
50% to about 100%, from about 60% to about 98%, from about 70% to about 95%,
although
may be present in greater or lesser amounts. Methods of producing such latex
resins may be
carried out as described in the disclosure of U.S. Pat. No. 7,524,602.
[0063] Colorants
[0064] Various known suitable colorants, such as dyes, pigments, mixtures
of dyes,
mixtures of pigments, mixtures of dyes and pigments and the like may be
included in the toner.
The colorant may be included in the toner in an amount of, for example, about
0.1 to about 35%
by weight of the toner, from about 1 to about 15% percent of the toner, from
about 3 to about
10% by weight of the toner, although amounts outside those ranges may be
utilized.
[0065] As examples of suitable colorants, mention may be made of carbon
black like
REGAL 330 ; magnetites, such as, Mobay magnetites M08029TM and MO8O6OTM;
Columbian
magnetites; MAPICO BLACKSTm, surface-treated magnetites; Pfizer magnetites
CB4799TM,
CB5300TM, CB5600TM and MCX6369TM; Bayer magnetites, BAYFERROX 8600TM and
8610TM;
Northern Pigments magnetites, NP6O4TM and NP608TM; Magnox magnetites TMB-100Tm
or
TMB-104Tm; and the like. As colored pigments, there can be selected cyan,
magenta, yellow,
red, green, brown, blue or mixtures thereof Generally, cyan, magenta or yellow
pigments or
dyes, or mixtures thereof, are used. The pigment or pigments can be water-
based pigment
dispersions.
[0066] Specific examples of pigments include SUNSPERSE 6000, FLEXIVERSE and
AQUATONE water-based pigment dispersions from SUN Chemicals, HELIOGEN BLUE
L6900TM, D6840TM, D7O8OTM, D7O2OTM, PYLAM OIL BLUETM, PYLAM OIL YELLOWTM,
PIGMENT BLUE 1TM available from Paul Uhlich & Company, Inc., PIGMENT VIOLET
1TM,
PIGMENT RED 48TM, LEMON CHROME YELLOW DCC 10261m, E.D. TOLUIDINE REDTM
and BON RED CTM available from Dominion Color Corporation, Ltd., Toronto,
Ontario,
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NOVAPERM YELLOW FGLTM, HOSTAPERM PINK ETM from Hoechst, CINQUASIA
MAGENTATm available from E.I. DuPont de Nemours & Company and the like.
Colorants that
can be selected are black, cyan, magenta, yellow and mixtures thereof Examples
of magentas
are 2,9-dimethyl-substituted quinacridone and anthraquinone dye identified in
the Color Index as
CI 60710, CI Dispersed Red 15, diazo dye identified in the Color Index as CI
26050, CI Solvent
Red 19 and the like. Illustrative examples of cyans include copper
tetra(octadecyl sulfonamido)
phthalocyanine, x-copper phthalocyanine pigment listed in the Color Index as
CI 74160, CI
Pigment Blue, Pigment Blue 15:3, Anthrathrene Blue, identified in the Color
Index as CI 69810,
Special Blue X-2137 and the like. Illustrative examples of yellows are
diarylide yellow 3,3-
dichlorobenzidene acetoacetanilides, a monoazo pigment identified in the Color
Index as CI
12700, CI Solvent Yellow 16, a nitrophenyl amine sulfonamide identified in the
Color Index as
Foron Yellow SE/GLN, CI Dispersed Yellow 33 2,5-dimethoxy-4-sulfonanilide
phenylazo-4'-
chloro-2,5-dimethoxy acetoacetanilide and Permanent Yellow FGL. Colored
magnetites, such
as, mixtures of MAPICO BLACKTM, and cyan components also may be selected as
colorants.
Other known colorants can be selected, such as, Levanyl Black A-SF (Miles,
Bayer) and
Sunsperse Carbon Black LHD 9303 (Sun Chemicals), and colored dyes, such as,
Neopen Blue
(BASF), Sudan Blue OS (BASF), PV Fast Blue B2G01 (American Hoechst), Sunsperse
Blue
BHD 6000 (Sun Chemicals), Irgalite Blue BCA (Ciba-Geigy), Paliogen Blue 6470
(BASF),
Sudan III (Matheson, Coleman, Bell), Sudan II (Matheson, Coleman, Bell), Sudan
IV
(Matheson, Coleman, Bell), Sudan Orange G (Aldrich), Sudan Orange 220 (BASF),
Paliogen
Orange 3040 (BASF), Ortho Orange OR 2673 (Paul Uhlich), Paliogen Yellow 152,
1560
(BASF), Lithol Fast Yellow 0991K (BASF), Paliotol Yellow 1840 (BASF), Neopen
Yellow
(BASF), Novoperm Yellow FG 1 (Hoechst), Permanent Yellow YE 0305 (Paul
Uhlich),
Lumogen Yellow D0790 (BASF), Sunsperse Yellow YHD 6001 (Sun Chemicals), Suco-
Gelb
L1250 (BASF), Suco-Yellow D1355 (BASF), Hostaperm Pink E (American Hoechst),
Fanal
Pink D4830 (BASF), Cinquasia Magenta (DuPont), Lithol Scarlet D3700 (BASF),
Toluidine
Red (Aldrich), Scarlet for Thermoplast NSD PS PA (Ugine Kuhlmann of Canada),
E.D.
Toluidine Red (Aldrich), Lithol Rubine Toner (Paul Uhlich), Lithol Scarlet
4440 (BASF), Bon
Red C (Dominion Color Company), Royal Brilliant Red RD-8192 (Paul Uhlich),
Oracet Pink RF
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PATENT APPLICATION
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(Ciba-Geigy), Paliogen Red 3871K (BASF), Paliogen Red 3340 (BASF), Lithol Fast
Scarlet
L4300 (BASF), combinations of the foregoing and the like.
[0067] Wax
[0068] In addition to the polymer resin, the toners of the present
disclosure also may
contain a wax, which can be either a single type of wax or a mixture of two or
more different
waxes. A single wax can be added to toner formulations, for example, to
improve particular toner
properties, such as, toner particle shape, presence and amount of wax on the
toner particle
surface, charging and/or fusing characteristics, gloss, stripping, offset
properties and the like.
Alternatively, a combination of waxes can be added to provide multiple
properties to the toner
composition.
[0069] When included, the wax may be present in an amount of, for example,
from about
lwt% to about 25wt% of the toner particles, in embodiments, from about 5wt% to
about 2Owt%
of the toner particles.
[0070] Waxes that may be selected include waxes having, for example, a
weight average
molecular weight of from about 500 to about 20,000, in embodiments from about
1,000 to about
10,000. Waxes that may be used include, for example, polyolefins, such as,
polyethylene,
polypropylene and polybutene waxes, such as, commercially available from
Allied Chemical and
Petrolite Corporation, for example POLYWAXTM polyethylene waxes from Baker
Petrolite, wax
emulsions available from Michaelman, Inc. and the Daniels Products Company,
EPOLENE N-
15Tm commercially available from Eastman Chemical Products, Inc., and VISCOL
550-PTm, a
low weight average molecular weight polypropylene available from Sanyo Kasei
K. K.; plant-
based waxes, such as, carnauba wax, rice wax, candelilla wax, sumacs wax and
jojoba oil;
animal-based waxes, such as, beeswax; mineral-based waxes and petroleum-based
waxes, such
as, montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax and
Fischer-Tropsch wax;
ester waxes obtained from higher fatty acid and higher alcohol, such as,
stearyl stearate and
behenyl behenate; ester waxes obtained from higher fatty acid and monovalent
or multivalent
lower alcohol, such as, butyl stearate, propyl oleate, glyceride monostearate,
glyceride distearate,
pentaerythritol tetra behenate; ester waxes obtained from higher fatty acid
and multivalent
alcohol multimers, such as, diethyleneglycol monostearate, dipropyleneglycol
distearate,
diglyceryl distearate and triglyceryl tetrastearate; sorbitan higher fatty
acid ester waxes, such as,
18
CA 02867713 2016-07-21
sorbitan monostearate, and cholesterol higher fatty acid cstcr waxes, such as,
cholcsteryl stearate.
Examples of functionalized waxes that may bc used include, for example,
amines, amides, for
example, AQUA SUPERSL1P 6550TM and SUPERSLIP 6530TM available from Micro
Powder
Inc., fluorinated waxes, for example, POLYFLUO 190', POLYFLUO 200", POLYSILK
19Tm
and POLYSILK 14TM available from Micro Powder Inc., mixed fluorinated, amide
waxes, for
example, MICROSPERSION 19TM available from Micro Powder Inc., imides, esters,
quaternary
amines, carboxylic acids or acrylic polymer emulsion, for example JONCRYL 74',
89TM
130Tm, 537TM and 538TM, all available from SC Johnson Wax, and chlorinated
polypropylenes
and polyethylenes available from Allied Chemical and Petrolite Corporation and
SC Johnson
wax. Mixtures and combinations of the foregoing waxes also may be used in
embodiments.
Waxes may be included as, for example, fuser roll release agents.
[0071] Toner Preparation
[0072] The toner particles may be prepared by any method within the purview
of one
skilled in the art. Although embodiments relating to toner particle production
are described
below with respect to emulsion-aggregation processes, any suitable method of
preparing toner
particles may be used, including chemical processes, such as suspension and
encapsulation
processes disclosed in U.S. Pat. Nos. 5,290,654 and 5,302,486. In embodiments,
toner
compositions and toner particles may be prepared by aggregation and
coalescence processes in
which smaller-sized resin particles are aggregated to the appropriate toner
particle size and then
coalesced to achieve the final toner particle shape and morphology.
[0073] In embodiments, toner compositions may be prepared by emulsion-
aggregation
processes, such as, a process that includes aggregating a mixture of an
optional wax and any
other desired or required additives, and emulsions including the resins
described above,
optionally with surfactants, as described above, and then coalescing the
aggregate mixture. A
mixture may be prepared by adding an optional wax or othcr materials, which
optionally also
may be in a dispersion(s) including a surfactant, to thc emulsion, which may
be a mixture of two
or more emulsions containing the resin. The pH of the resulting mixture may be
adjusted by an
acid (i.e., a pH adjustor) such as, for example, acetic acid, nitric acid or
the like. In
embodiments, the pH of the mixture may be adjusted to from about 2 to about
4.5. Additionally,
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PATENT APPLICATION
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in embodiments, the mixture may be homogenized. If the mixture is homogenized,
homogenization may be accomplished by mixing at about 600 to about 4,000
revolutions per
minute (rpm). Homogenization may be accomplished by any suitable means,
including, for
example, with an IKA ULTRA TURRAX T50 probe homogenizer or a Gaulin 15MR
homgenizer.
[0074] Following preparation of the above mixture, generally, an
aggregating agent may be
added to the mixture. Suitable aggregating agents include, for example,
aqueous solutions of a
divalent cation or a multivalent cation material. In the present embodiments,
a polyaluminum
halide, specifically, polyaluminum chloride (PAC) is used. PAC is a stronger
multivalent
flocculant as compared to aluminum sulfate, which is a bivalent flocculant. It
was discovered
that the PAC unexpectedly improves the surface morphology by reducing the
amount of styrene-
acrylate on the surface. It is believed that the multivalent PAC helps bind
and keep the higher
acid value styrene-acrylate latex to the core of the toner particles.
[0075] In using the PAC, the manufacturing process is modified to lengthen
the
coalescence time (as compared to that used with conventional floceulants like
aluminum sulfate)
to from about 1 hour to about 3 hours, or from about 1.5 hours to about 2.5
hours. It was
discovered that this modification of longer coalescence time is needed to
smooth the toner
surface and obtain optimal surface morphology.
[0076] Other aggregating agents that may be used include the corresponding
bromide,
fluoride or iodide, and combinations thereof. In embodiments, the aggregating
agent is present
in the toner composition in an amount of from about 0.1 to about 1.0 percent,
or of from about
0.2 to about 0.8 percent, or of from about 0.25 to about 0.5 percent by weight
of the total weight
of the toner particles. In embodiments, the aggregating agent may be added to
the mixture at a
temperature that is below the glass transition temperature (Tg) of the resin.
As discussed above,
the reduced coalescence temperature used is from about 70 to about 90 C, or
from about 70 to
about 80 C, or from about 70 to about 77 C.
[0077] The aggregating agent may be added to the mixture to form a toner in
an amount of,
for example, from about 0.1 parts per hundred (pph) to about lpph of the toner
particles, in
embodiments, from about 0.25pph to about 0.75pph of the toner particles.
CA 02867713 2016-07-21
[0078] The gloss of a toner may bc influenced by the amount of retained
metal ion, such
as, A13 , in the particle. The amount of retained metal ion may be adjusted
further by the
addition of ethylene diamine tetraacetic acid (EDTA). In embodiments, the
amount of retained
metal ion, for example, A13+, in toner particles of the present disclosure may
be from about
0.1pph to about lpph, in embodiments, from about 0.25pph to about 0.8pph.
100791 The disclosure also provides a melt mixing process to produce low
cost and safe
cross-linked thermoplastic binder resins for toner compositions which have,
for example, low fix
temperature and/or high offset temperature, and which may show minimized or
substantially no
vinyl offset. In the process, unsaturated base polyester resins or polymers
are melt blended, that
is, in the molten state under high shear conditions producing substantially
uniformly dispersed
toner constituents, and which process provides a resin blend and toner product
with optimized
gloss properties (see, e.g., U.S. Pat. No. 5,556,732). By, "highly cross-
linked," is meant that the
polymer involved is substantially cross-linked, that is, equal to or above the
gel point. As used
herein, "gel point,- means the point where the polymer is no longer soluble in
solution (see, e.g.,
U.S. Pat. No. 4,457,998).
[0080] To control aggregation and coalescence of the particles, in
embodiments, the
aggregating agent may be metered into the mixture over time. For example, the
agent may be
metered into the mixture over a period of from about 5 to about 240min, in
embodiments, from
about 30 to about 200min. Addition of the agent may also be done while the
mixture is
maintained under stirred conditions, in embodiments from about 5Orpm to about
1,00Orpm, in
embodiments, from about 10Orpm to about 500rpm, and at a temperature that is
below the Tg of
the resin.
[0081] The particles may be permitted to aggregate until a predetermined
desired particle
size is obtained. A predetermined desired size refers to the desired particle
size as determined
prior to formation, with particle size monitorcd during the growth process as
known in the art
until such particle size is achieved. Samples may be taken during the growth
process and
analyzed, for example with a Coulter Counter, for average particle size. The
aggregation thus
may proceed by maintaining the elevated temperature, or slowly raising the
temperature to, for
example, from about 40 C to about 65 C, and holding the mixture at that
temperature for a time
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PATENT APPLICATION
= Attorney Docket No. 20131086CA01
from about 0.5hr to about 6hr, in embodiments, from about lhr to about 5hr,
while maintaining
stirring, to provide the aggregated particles. Once the predetermined desired
particle size is
obtained, the growth process is halted. In embodiments, the predetermined
desired particle size
is within the toner particle size ranges mentioned above. In embodiments, the
particle size may
be about 5.0 to about 6.0um, about 6.0 to about 6.5m, about 6.5 to about
7.0um, about 7.0 to
about 7.5um.
[0082] Growth and shaping of the particles following addition of the
aggregation agent
may be accomplished under any suitable conditions. For example, the growth and
shaping may
be conducted under conditions in which aggregation occurs separate from
coalescence. For
separate aggregation and coalescence stages, the aggregation process may be
conducted under
shearing conditions at an elevated temperature, for example from about 40 C to
about 00 C, in
embodiments, from about 45 C to about 80 C, which may be below the Tg of the
resin.
[0083] Following aggregation to the desired particle size, with the
optional formation of a
shell as described above, the particles then may be coalesced to the desired
final shape, the
coalescence being achieved by, for example, heating the mixture to a
temperature of from about
55 C to about 100 C, in embodiments from about 65 C to about 75 C, which may
be below the
melting point of a crystalline resin to prevent plasticization. Higher or
lower temperatures may
be used, it being understood that the temperature is a function of the resins
used.
[0084] Coalescence may proceed over a period of from about 0.1 to about
9hr, in
embodiments, from about 0.5 to about 4hr.
[0085] After coalescence, the mixture may be cooled to room temperature,
such as from
about 20 C to about 25 C. The cooling may be rapid or slow, as desired. A
suitable cooling
method may include introducing cold water to a jacket around the reactor.
After cooling, the
toner particles optionally may be washed with water and then dried. Drying may
be
accomplished by any suitable method, for example, freeze drying.
[0086] Toners may possess favorable charging characteristics when exposed
to extreme
RH conditions. The low humidity zone (C zone) may be about 12 C/15% RH, while
the high
humidity zone (A zone) may be about 28 C/85% RH. Toners of the disclosure may
possess a
parent toner charge per mass ratio (Q/M) of from about -5 C/g to about -80
C/g, in
embodiments, from about -10 C/g to about -70 C/g, and a final toner charging
after surface
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= PATENT APPLICATION
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additive blending of from -151.1.C/g to about -601.1C/g, in embodiments, from
about -201aC/g to
about -55 C/g.
[0087] Shell Resin
100881 In embodiments, a shell may be applied to the formed aggregated
toner particles.
Any resin described above as suitable for the core resin may be utilized as
the shell resin. The
shell resin may be applied to the aggregated particles by any method within
the purview of those
skilled in the art. In embodiments, the shell resin may be in an emulsion
including any surfactant
described herein. The aggregated particles described above may be combined
with said emulsion
so that the resin forms a shell over the formed aggregates. In embodiments, an
amorphous
polyester may be utilized to form a shell over the aggregates to form toner
particles having a
core-shell configuration.
[0089] Toner particles can have a size of diameter of from about 4 to
about 81am, in
embodiments, from about 5 to about 7 m, the optimal shell component may be
about 26 to about
30% by weight of the toner particles.
[0090] Alternatively, a thicker shell may be desirable to provide
desirable charging
characteristics due to the higher surface area of the toner particle. Thus,
the shell resin may be
present in an amount from about 30% to about 40% by weight of the toner
particles, in
embodiments, from about 32% to about 38% by weight of the toner particles, in
embodiments,
from about 34% to about 36% by weight of the toner particles.
[0091] In embodiments, a photoinitiator may be included in the shell.
Thus, the
photoinitiator may be in the core, the shell, or both. The photoinitiator may
be present in an
amount of from about 1% to about 5% by weight of the toner particles, in
embodiments, from
about 2% to about 4% by weight of the toner particles.
[0092] Emulsions may have a solids loading of from about 5% solids by
weight to about
20% solids by weight, in embodiments, from about 12% solids by weight to about
17% solids by
weight.
[0093] Once the desired final size of the toner particles is achieved,
the pH of the mixture
may be adjusted with a base (i.e., a pH adjustor) to a value of from about 6
to about 10, and in
embodiments from about 6.2 to about 7. The adjustment of the pH may be
utilized to freeze, that
is to stop, toner growth. The base utilized to stop toner growth may include
any suitable base,
23
CA 02867713 2016-07-21
such as, for example, alkali metal hydroxides, such as, for example, sodium
hydroxide,
potassium hydroxide, ammonium hydroxide, combinations thereof and the like. In
embodiments,
EDTA may be added to help adjust the pH to the dcsircd values noted above. The
base may be
added in amounts from about 2 to about 25% by weight of the mixture, in
embodiments, from
about 4 to about 10% by weight of the mixture. In embodiments, the shell has a
higher Tg than
the aggregated toner particles.
[0094] Carriers
[0095] Various suitable solid core or particle materials can be utilized
for the carriers and
developers of the present disclosure. Characteristic particle properties
include those that, in
embodiments, will enable the toner particles to acquire a positive charge or a
negative charge,
and carrier cores that provide desirable flow properties in the developer
reservoir present in an
electrophotographic imaging apparatus. Other desirable properties of the core
include, for
example, suitable magnetic characteristics that permit magnetic brush
formation in magnetic
brush development processes; desirable mechanical aging characteristics; and
desirable surface
morphology to permit high electrical conductivity of any developer including
the carrier and a
suitable toner.
[0096] Examples of carrier particles or cores that can be utilized include
iron and/or steel,
such as, atomized iron or steel powders available from Hoeganaes Corporation
or Pomaton S.p.A
(Italy); ferrites, such as, Cu/Zn-ferrite containing, for example, about 11%
copper oxide, about
19% zinc oxide, and about 70% iron oxide, including those commercially
available from D.M.
Steward Corporation or Powdertech Corporation, Ni/Zn-ferrite available from
Powdertech
Corporation, Sr (strontium)-ferrite, containing, for example, about 14%
strontium oxide and
about 86% iron oxide, commercially available from Powdertech Corporation, and
Ba-ferrite;
magnetites, including those commercially available from, for example,
Hoeganaes Corporation
(Sweden); nickel; combinations thereof, and the like. In embodiments, the
polymer particles
obtained can be used to coat carrier cores of any known type by various known
methods, and
which carriers then are incorporated with a known toner to form a developer
for
electrophotographic printing. Other suitable carrier cores are illustrated in,
for example, U.S.
Patent Nos. 4,937,166, 4,935,326 and 7,014,971 and may include granular
zircon, granular
silicon, glass,
24
CA 02867713 2014-10-17
PATENT APPLICATION
Attorney Docket No. 20131086CA01
silicon dioxide, combinations thereof, and the like. In embodiments, suitable
carrier cores may
have an average particle size of, for example, from about 20pm to about 400pm
in diameter, in
embodiments, from about 4011m to about 200pm in diameter.
[0097] In embodiments, a ferrite may be utilized as the core, including a
metal, such as,
iron and at least one additional metal, such as, copper, zinc, nickel,
manganese, magnesium,
calcium, lithium, strontium, zirconium, titanium, tantalum, bismuth, sodium,
potassium,
rubidium, cesium, strontium, barium, yttrium, lanthanum, hafnium, vanadium,
niobium,
aluminum, gallium, silicon, germamium, antimony, combinations thereof and the
like.
[0098] In some embodiments, the carrier coating may include a conductive
component.
Suitable conductive components include, for example, carbon black.
[0099] There may be added to the carrier a number of additives, for
example, charge
enhancing additives, including particulate amine resins, such as, melamine,
and certain
fluoropolymer powders, such as alkyl-amino acrylates and methacrylates,
polyamides, and
fluorinated polymers, such as polyvinylidine fluoride and
poly(tetrafluoroethylene) and
fluoroalkyl methacrylates, such as 2,2,2-trifluoroethyl methacrylate. Other
charge enhancing
additives which may be utilized include quaternary ammonium salts, including
distearyl
dimethyl ammonium methyl sulfate (DDAMS), bis[1-[(3,5-disubstituted-2-
hydroxyphenypazo]-
3-(mono-substituted)-2-naphthalenolato(2-)]chromate(1-), ammonium sodium and
hydrogen
(TRH), cetyl pyridinium chloride (CPC), FANAL PINK D4830, combinations
thereof, and the
like, and other effective known charge agents or additives. The charge
additive components may
be selected in various effective amounts, such as from about 0.5wt% to about
20wt%, from about
I wt% to about 3wt%, based, for example, on the sum of the weights of
polymer/copolymer,
conductive component, and other charge additive components. The addition of
conductive
components can act to further increase the negative triboelectric charge
imparted to the carrier,
and therefore, further increase the negative triboelectric charge imparted to
the toner in, for
example, an electrophotographic development subsystem. The components may be
included by
roll mixing, tumbling, milling, shaking, electrostatic powder cloud spraying,
fluidized bed,
electrostatic disc processing, and an electrostatic curtain, as described, for
example, in U.S.
Patent No. 6,042,981, the disclosure of which hereby is incorporated by
reference in entirety, and
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PATENT APPLICATION
= Attorney Docket No. 20131086CA01
wherein the carrier coating is fused to the carrier core in either a rotary
kiln or by passing
through a heated extruder apparatus.
[00100] Conductivity can be important for semiconductive magnetic brush
development to
enable good development of solid areas which otherwise may be weakly
developed. Addition of
a polymeric coating of the present disclosure, optionally with a conductive
component such as
carbon black, can result in carriers with decreased developer triboelectric
response with change
in relative humidity of from about 20% to about 90%, in embodiments, from
about 40% to about
80%, that the charge is more consistent when the relative humidity is changed.
Thus, there is
less decrease in charge at high relative humidity reducing background toner on
the prints, and
less increase in charge and subsequently less loss of development at low
relative humidity,
resulting in such improved image quality performance due to improved optical
density.
[00101] As noted above, in embodiments the polymeric coating may be dried,
after which
time it may be applied to the core carrier as a dry powder. Powder coating
processes differ from
conventional solution coating processes. Solution coating requires a coating
polymer whose
composition and molecular weight properties enable the resin to be soluble in
a solvent in the
coating process. That requires relatively low My, components as compared to
powder coating.
The powder coating process does not require solvent solubility, but does
require the resin coated
as a particulate with a particle size of from about lOnm to about 2p,m, in
embodiments, from
about 30nm to about lum, in embodiments, from about 50nm to about 500nm.
[00102] Examples of processes which may be utilized to apply the powder
coating include,
for example, combining the carrier core material and resin coating by cascade
roll mixing,
tumbling, milling, shaking, electrostatic powder cloud spraying, fluidized
bed, electrostatic disc
processing, electrostatic curtains, combinations thereof and the like. When
resin coated carrier
particles are prepared by a powder coating process, the majority of the
coating materials may be
fused to the carrier surface, thereby reducing the number of toner impaction
sites on the carrier.
Fusing of the polymeric coating may occur by mechanical impaction,
electrostatic attraction,
combinations thereof and the like.
[00103] Following application of the resin to the core, heating may be
initiated to permit
flow of the coating material over the surface of the carrier core. The
concentration of the coating
material, in embodiments, powder particles, and the parameters of the heating
may be selected to
26
CA 02867713 2016-07-21
enable the formation of a continuous film of the coating polymers on the
surface of the carrier
core, or permit only selected areas of the carrier core to be coated. In
embodiments, the carrier
with the polymeric powder coating may be heated to a temperature of from about
170 C to about
280 C, in embodiments from about 190 C to about 240 C, for a period of time
of, for example,
from about 10min to about 180min, in embodiments, from about 15min to about
60min, to
enable the polymer coating to melt and to fuse to the carrier core particles.
Following
incorporation of the powder on the surface of the carrier, heating may be
initiated to permit flow
of the coating material over the surface of the carrier core. In embodiments,
the powder may be
fused to the carrier core in either a rotary kiln or by passing through a
heated extruder apparatus,
see, for example, U.S. Patent No. 6,355,391.
[00104] In embodiments, the coating coverage encompasses from about 10% to
about 100%
of the carrier corc. When selected areas of the metal carrier core remain
uncoated or exposed,
thc carrier particles may possess electrically conductive properties when the
core material is a
metal.
[00105] The coated carrier particles may then be cooled, in embodiments to
room
temperature, and recovered for use in forming developer.
[00106] In embodiments, carriers of the present disclosure may include a
core, in
embodiments, a ferrite core, having a size of from about 201,tm to about
100um, in embodiments,
from about 30um to about 75[im, coated with from about 0.5% to about 10% by
weight, in
embodiments, from about 0.7% to about 5% by weight, of the polymer coating of
the present
disclosure, optionally including carbon black.
[00107] Thus, with the carrier compositions and processes of the present
disclosure, there
can be formulated developers with selected high triboelectric charging
characteristics and/or
conductivity values utilizing a number of different combinations.
[001081 Developers
[00109] The toner particles thus formed may be formulated into a developer
composition.
The toner particles may be mixed with carrier particles to achieve a two
component developer
composition. The toner concentration in the developer may be from about 1% to
about 25% by
weight of the total weight of the developer, in embodiments, from about 2% to
about 15% by
weight of the total weight of the developer.
27
CA 02867713 2016-07-21
[00110] Imaging
[00111] The toners can be utilized for electrophotographic processes,
including those
disclosed in U.S. Pat. No. 4,295,990. In embodiments, any known type of image
development
system may be used in an image developing device, including, for example,
magnetic brush
development, hybrid scavengeless development (I-ISD) and the like. Those and
similar
development systems are within the purview of those skilled in the art.
[00112] It is envisioned that the toners of the present disclosure may be
used in any suitable
procedure for forming an image with a toner, including in applications other
than xerographic
applications.
[00113] Utilizing the toners of the present disclosure, images may be
formed on substrates,
including flexible substrates, having a toner pile height of from about lpm to
about 6 ,m, in
embodiments, from about 2pm to about 4.5 m, in embodiments, from about 2.5 to
about 4.2 m.
[00114] In embodiments, the toner of the present disclosure may be used for
a xerographic
print protective composition that provides overprint coating properties
including, but not limited
to, thermal and light stability and smear resistance, particularly in
commercial print applications.
More specifically, such overprint coating as envisioned has the ability to
permit overwriting,
reduce or prevent thermal cracking, improve fusing, reduce or prevent document
offset, improve
print performance and protect an image from sun, heat and the like. In
embodiments, the
overprint compositions may be used to improve the overall appearance of
xerographic prints due
to the ability of the compositions to fill in the roughness of xerographic
substrates and toners,
thereby forming a level film and enhancing glossiness.
[00115] The following Examples are submitted to illustrate embodiments of
the disclosure.
The Examples are intended to be illustrative only and are not intended to
limit the scope of the
disclosure. Also, parts and percentages are by weight unless otherwise
indicated. As used herein,
"room temperature," refers to a temperature of from about 20 C to about 30 C.
EXAMPLES
28
CA 02867713 2014-10-17
PATENT APPLICATION
Attorney Docket No. 20131086CA01
[00116] The examples set forth herein below are being submitted to illustrate
embodiments of
the present disclosure. These examples are intended to be illustrative only
and are not intended
to limit the scope of the present disclosure. Also, parts and percentages are
by weight unless
otherwise indicated. Comparative examples and data are also provided.
[00117] Control
[00118] Control Toner Example 1: Preparation of 22% styrene-acrylate core
(latex
particle size 162nm) Black Toner Particle at 70 C
[00119] In a 2L reactor, 43g of amorphous polyester emulsion (FXC42
available from Kao
Corporation), 47g of amorphous polyester emulsion (FXC56 available from Kao
Corporation),
81g styrene-acrylate latex (comprised of 23.5 % n-butylacrylate, 76.5 %
styrene with an average
molecular weight of 55,000 g/mole, particle size 162nm), 29g crystalline
polyester emulsion, 43g
wax, 9.6g cyan pigment, 57g black pigment (Nipex-35), 0.7g surfactant (Dowfax)
and 534g de-
ionized water (DI) water are combined. Then 2.7g of aluminum sulphate
(Al2(SO4)3) mixed
with 33g DI water is added to the slurry under homogenization at 3000-4000
RPM. The reactor
is set to 260 RPM and is heated to 42C to aggregate the toner particles. When
the size reaches
4.8-5 m, a shell coating is added which consists of 69g of amorphous polyester
emulsion
(FXC42), 74g of amorphous polyester emulsion (FXC56) with 1.15g surfactant
(Dowfax) and all
ph adjusted to 3.3 using 0.3M nitric acid. The reaction is further heated to
50C. When the toner
particle size reaches 5.6 - 6 microns, freezing begins with the pH of the
slurry being adjusted to
4.5 using a 4% NaOH solution. The reactor RPM is decreased to 220 followed by
the addition of
5.77 grams of a chelating agent (Versene100) and more NaOH solution until pH
reaches 7.8.
The reactor temperature is ramped to 70C. The pH of the slurry is maintained
at 7.8 or greater
until 70C. Once at the coalescence temperature, the slurry pH is reduced to
6.0 using pH 5.7
Buffer and is coalesced for about 1 hour until the particle circularity is
between 0.955 ¨ 0.960 as
measured by the Flow Particle Image Analysis (FPIA) instrument. The slurry is
then quench
cooled in 770g DI ice. The final particle size was 5.90 microns, GSDv 1.21,
GSDn 1.22 and a
circularity of 0.958. The toner is then washed and freeze-dried.
[00120] Example 1
[00121] Toner Example 1: Preparation of Hybrid Black Toner Particle with
Al2(SO4)3
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PATENT APPLICATION
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[00122] In a 2L reactor, 43g of amorphous polyester emulsion (), 47g of
amorphous
polyester emulsion (FXC56), 82g styrene-acrylate latex (comprised of 23.5 % n-
butylacrylate,
76.5 A styrene with an average molecular weight of 55,000 g/mole, particle
size 162nm , particle
size 141nm), 29g crystalline polyester emulsion, 43g wax, 9.6g cyan pigment,
57g black pigment
(Nipex-35), 0.7g surfactant (Dowfax) and 534g DI water are combined. Then 2.7g
of aluminum
sulphate (Al2(SO4)3) mixed with 33g DI water is added to the slurry under
homogenization at
3000-4000 RPM. The reactor is set to 260 RPM and is heated to 42C to aggregate
the toner
particles. When the size reaches 4.8-5 m, a shell coating is added which
consists of 69g of
amorphous polyester emulsion (FXC42), 74g of amorphous polyester emulsion
(FXC56) with
1.15g surfactant (Dowfax) and all pH adjusted to 3.3 using 0.3M nitric acid.
The reaction is
further heated to 50C. When the toner particle size reaches 5.6 - 6 microns,
freezing begins with
the pH of the slurry being adjusted to 4.5 using a 4% NaOH solution. The
reactor RPM is
decreased to 220 followed by the addition of 5.77 grams of a chelating agent
(Versene100) and
more NaOH solution until pH reaches 7.8. The reactor temperature is ramped to
70C. The pH of
the slurry is maintained at 7.8 or greater until 70C. Once at the coalescence
temperature, the
slurry pH is reduced to 6.0 using pH 5.7 Buffer and is coalesced for about 1
hour until the
particle circularity is between 0.955 ¨ 0.960 as measured by the Flow Particle
Image Analysis
(FPIA) instrument. The slurry is then quench cooled in 770g DI ice. The final
particle size was
6.0 microns, GSDv 1.21, GSDn 1.24 and a circularity of 0.955. The toner is
then washed and
freeze-dried.
[00123] Example 2
[00124] Toner Example 2: Preparation of Hybrid Black Toner Particle with
PAC
[00125] In a 2L reactor, 43g of amorphous polyester emulsion (FXC42), 47g
of amorphous
polyester emulsion (FXC56), 82g styrene-acrylate latex (comprised of 23.5 % n-
butylacrylate,
76.5 % styrene with an average molecular weight of 55,000 g/mole, particle
size 141nm, particle
size 141nm), 29g crystalline polyester emulsion, 43g wax, 9.6g cyan pigment,
57g black pigment
(Nipex-35), 0.7g surfactant (Dowfax) and 534g DI water are combined. Then 2.7g
of
polyaluminum chloride (PAC) mixed with 24g 0.02M nitric acid is added to the
slurry under
homogenization at 3000-4000 RPM. The reactor is set to 260 RPM and is heated
to 42C to
aggregate the toner particles. When the size reaches 4.8-5um, a shell coating
is added which
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PATENT APPLICATION
Attorney Docket No. 20131086CA01
consists of 69g of amorphous polyester emulsion (FXC42), 74g of amorphous
polyester
emulsion (FXC56) with 1.15g surfactant (Dowfax) and all pH adjusted to 3.3
using 0.3M nitric
acid. The reaction is further heated to 50C. When the toner particle size
reaches 5.6 - 6 microns,
freezing begins with the pH of the slurry being adjusted to 4.5 using a 4%
NaOH solution. The
reactor RPM is decreased to 220 followed by the addition of 5.77 grams of a
chelating agent
(Versene100) and more NaOH solution until pH reaches 7.8. The reactor
temperature is ramped
to 70C. The pH of the slurry is maintained at 7.8 or greater until 70C. Once
at the coalescence
temperature, the slurry pH is reduced to 6.0 using pH 5.7 Buffer and is
coalesced for about 2
hour until the particle circularity is between 0.955 ¨ 0.960 as measured by
the Flow Particle
Image Analysis (FPIA) instrument. The slurry is then quench cooled in 770g DI
ice. The final
particle size was 6.3 microns. GSDv 1.23, GSDn 1.25 and a circularity of
0.955. The toner is
then washed and freeze-dried.
[00126] Comparative Examples
1001271 Xerox 700 Toner (Cyan or Black)
[00128] This commercially available toner was used as comparison to the
inventive toners.
The Xerox 700 Toner is comprised of an emulsion aggregation toner, wherein the
core is
comprised of about 6 to 7 percent by weight of crystalline resin, 5 to 6
percent by weight of Cyan
or Black pigment, 8 to 10 percent by weight of Wax, and about 50 to about 52
percent by weight
of amorphous polyester resin, and wherein the shell is from about 28 percent
by weight of toner
[00129] Xerox Docucolor 2240 Cyan Toner
[00130] This commercially available toner was used as comparison to the
inventive toners.
The Xerox Docucolor 2240 Toner is comprised of an emulsion aggregation toner,
wherein the
core is comprised of 5 to 6 percent by weight of Cyan or Black pigment, 10-12
percent by weight
of Wax, and about 54 to about 56 percent by weight of Styrene-acrylate resin,
and wherein the
shell is a styrene-acrylate resin of from about 28 percent by weight of toner.
[00131] Table 1 shows the features and properties of the Control, Toner
Examples 1 and 2
as well as an emulsion aggregate polyester-based toner (Xerox 700 Toner-. The
Control and
Toner Examples 1 and 2 all incorporate at least 20% styrene-acrylate latex.
Toner Example 2
has PAC as the flocculant.
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Table 1
TONER ID Xerox 700 Toner Control Toner Example 1 Toner Example
2
22% amorphous 22% amorphous 22% amorphous
polyester polyester polyester
50% amorphous
22% sty-acrylate 22% sty-acrylate 22% sty-
Core latex(large latex size: (small latex size:
acrylate(small latex
7% crystalline
161nm) 141nm) size: 141nm)
polyester
7% crystalline 7% crystalline 7% crystalline
polyester polyester polyester
Shell latex 28% amorphous 34% amorphous 34% amorphous 34%
amorphous
polyester polyester polyester polyester
Coal. Temp 70
85 70 70
( C)
Flocculant Al2(SO4)3 Al2(SO4)3 Al2(SO4)3 PAC
D50 5.90 6.0 6.3
GSDv/n 1.21/1.22 1.21/1.24 1.23/1.25
Circularity 0.958 0.955 0.955
[00132] SEM images were taken of the Control and Toner Examples 1 and 2, as
shown in
Figure 1. As can be seen from Figure 1, the surface does improve with smaller
size
polystyrene/acrylate latex (the Control as compared to Toner Example 1) and an
even larger
improvement is seen when the flocculant is changed to PAC (Toner Example 2).
[00133] These toners were then analyzed for charging and fusing performance,
the results are
below.
[00134] Developer Performance Results
[00135] Charging performance is comparable to the standard EA polyester toner,
however, the
main concern is the blocking onset and % heat cohesion. These two properties
are not as good as
the Polyester Control Toner, however, after some investigation it was noticed
that the surface
morphology of the toners were worse than the Polyester Control Toner. As seen
in the toner
SEM images, the toner surface contained a lot of polystyrene/acrylate latex
and some wax
particles. The wax content is typical; however, the polystyrene/acrylate on
the surface prevents
the toner additives from properly covering the toner surface and as well
negatively impacts the
toner performance. Surprisingly, when the flocculant was switched to PAC to
flocculate the
toner, it can be seen that the toner surface improves. The
polystyrene/acrylate latex does not
protrude to the surface of the toner, but rather remains more in the center of
the toner.
Table 2
32
CA 02867713 2014-10-17
PATENT APPLICATION
Attorney Docket No. 20131 086CA01
Sample conditioned in J-Zone for 24 hours. Capacitance and
loss factor measured at 100KHz and 1VAC.
E" *
E% (dielectric
1000
constant)
(loss)
Xerox 700 Toner 3.61 36
Control = 3.10 34
Toner Example 1 3 .40 36
Toner Example 2 3.08 27
As can be seen from the above Table 2, the toner dielectric loss remains
comparable to the
Polyester Control Toner if not even improves with the improved surface
morphology.
[00136] Table 3 below shows the toner blocking results for the various hybrid
examples.
Table 3
Blocking Onset
Xerox 700 Toner (Black) 53 C
KN749K <51 C
KN754K 51C
KN758K 52C
The blocking for Toner Example 2 is within experimental error of the Polyester
Control Toner
(Xerox 700 Toner); whereas the previous two samples (the Control and Toner
Example 1) have
noticeable shortfalls.
[00137] Figure 2 shows how the % heat cohesion of the toner of the present
embodiments is
also improved as compared to the Control and Toner Example 1, without PAC as
the flocculant.
[00138] Summary of Fusing Results
[00139] Gloss, crease and hot offset data of particles was collected with
samples fused onto
Color Xpressions Select (90 gsm) using an in-house fusing fixture. The toners
were within
experimental uncertainty of the Polyester Control Toner reference samples.
[00140] The Control
[00141] Print gloss curve of this hybrid toner was between the Xerox 700
Toner, Xerox
Docucolor 2240 comparative reference samples and has a lower peak gloss (57 gu
versus 63 gu).
The temperature needed to reach 50 gloss units is 158 C while the Xerox
Docucolor 2240 toner
required 166 C and the Polyester Control Toner required 146 C.
33
CA 02867713 2016-07-21
[00142] Crease fix minimum fix temperature (Mil) of this hybrid toner was
lower than the
Xerox 700 Toner (117 C versus 123 C) and much lower than the Xerox Docueolor
2240 toner
(117 C versus 143 C). Lab scale and bench scale particles can have crease fix
MFT's less than
production scale particles.
[00143] There was no toner hot offset to the fuser roll at 210 C resulting
in wide fusing
latitude.
[00144] Toner Example 1 and 2
[00145] Print gloss of this hybrid toner is approaching the design gloss
and bench scale
polyester toner and crease fix MFT is lower than production polyester toner
MFT. Both hybrid
toners had a very low crease fix MFT and gloss curve approaching the polyester
toner gloss
curve. The lower coalescence curve and small styrene acrylate latex particles
did not
significantly impact the fusing performance of thc hybrid design.
[00146] Fusing results were consistent with the previous hybrid particles.
[00147] It will be appreciated that several of the above-disclosed and
other features and
functions, or alternatives thereof, may be desirably combined into many other
different systems
or applications. Also various presently unforeseen or unanticipated
alternatives, modifications,
variations or improvements therein may be subsequently made by those skilled
in the art, which
are also intended to be encompassed by the following claims.
[00148] Unless specifically recited in a claim, steps or components of
claims should not be
implied or imported from the specification or any other claims as to any
particular order,
number, position, size, shape, angle, color or material.
34
