METHOD OF USING ALDEHYDE-FUNCTIONALIZED POLYMERS TO
INCREASE PAPERMACHINE PERFORMANCE AND ENHANCE SIZING
TECHNICAL FIELD
[0001] Disclosed herein are compositions and methods for improving paper and
paperboard production. More specifically, disclosed are compositions and methods for
using aldehyde-functionalized polymers as emulsion stabilizers for sizing emulsions.
BACKGROUND
[0002] Sizing agents are used in the papermaking process to increase wood fiber's
resistance to liquid penetration. The resistance to the absorption of liquids is desired
when the paper product is purposefully wetted during a converting process (printing or
laminating) or accidentally wetted (packaging containers or newspapers). Alkenyl
succinic anhydride (ASA) is an internal sizing agent, which is commonly used to treat
fibers in the papermaking process, making them more hydrophobic. Internal sizing
refers to the treatment of the wood fibers prior to forming a wet web. ASA is a water
insoluble oil that is essentially nonionic in nature. Therefore, ASA must be emulsified
before it is added to the papermaking process. Emulsification of ASA produces an oil
in water emulsion and also cationizes the ASA emulsion droplets. Cationizing the
ASA droplets helps to promote emulsion stability and aids in ASA retention. Cationic
emulsifiers such as derivitized starches and synthetic acrylamide-based polymers are
currently used as emulsifiers for ASA.
[0003] Despite available technologies, there exists a need to improve sizing
performance and machine efficiency in paper production processes. There also exists
an ongoing industrial need in the papermaking industry to develop sizing formulations
and methods that improve sizing of paper and paperboard and also provide other
enhancements to papermaking process to reduce the need for multiple chemistries.
SUMMARY
[0004] In one aspect, disclosed herein is a sizing emulsion including a) a sizing
agent, b) an emulsifier, and c) an aqueous component.
[0005] In certain embodiments, the sizing agent is selected from the group
consisting of an alkyl ketene dimer ("AKD") and an alkenyl succinic anhydride (ASA).
[0006] In certain embodiments, the emulsifier is selected from the group consisting
of: glyoxalated poly(DADMAC)/AcAm polymer having a 5 mole DADMAC
monomer content; glyoxalated poly(DADMAC)/AcAm polymer having a 5 mole
DADMAC monomer content and further comprising MgS0 4-7H20 ; glyoxalated
poly(DADMAC)/AcAm polymer having a 12 mole DADMAC monomer content;
and glyoxalated poly(DADMAC)/AcAm polymer having a 12 mole DADMAC
monomer content and further comprising MgS0 4-7H20 . In certain embodiments, the
emulsifier is glyoxalated poly(DADMAC)/AcAm polymer having a 5 mole
DADMAC monomer content. In certain embodiments, the emulsifier is glyoxalated
poly(DADMAC)/AcAm polymer having a 5 mole DADMAC monomer content and
further comprising MgS0 4-7H20 . In certain embodiments, the emulsifier is
glyoxalated poly(DADMAC)/AcAm polymer having a 12 mole DADMAC monomer
content. In certain embodiments, the emulsifier is glyoxalated poly(DADMAC)/AcAm
polymer having a 12 mole DADMAC monomer content and further comprising
MgS0 4-7H20 .
[0007] In certain embodiments, the emulsifier is glyoxalated
poly(DADMAC)/AcAm polymer having a weight average molecular weight of at least
about 300 kiloDaltons (kD). In certain embodiments, the emulsifier is glyoxalated
poly(DADMAC)/AcAm polymer having a 5 mole DADMAC monomer content, said
polymer having a weight average molecular weight ranging from 1000 kiloDaltons
(kD) to about 2500 kD. In certain embodiments, the emulsifier is glyoxalated
poly(DADMAC)/AcAm polymer having a 5 mole DADMAC monomer content and
further comprising MgS0 4-7H20 , said polymer having a weight average molecular
weight ranging from 600 kiloDaltons (kD) to 1500 kD. In certain embodiments, the
emulsifier is glyoxalated poly(DADMAC)/AcAm polymer having a 12 mole
DADMAC monomer content, said polymer having a weight average molecular weight
ranging from 500 kiloDaltons (kD) to 2,000 kD. In certain embodiments, the
emulsifier is glyoxalated poly(DADMAC)/AcAm polymer having a 12 mole
DADMAC monomer content and further comprising MgS0 4-7H20 , said polymer
having a weight average molecular weight ranging from 500 kiloDaltons (kD) to 2,000
kD.
[0008] In certain embodiments, the sizing emulsion has a median particle size of less
than or equal to 2.5 microns, less than or equal to 2.0 microns, less than or equal to 1.5
microns, less than or equal to 1.4 microns, or less than or equal to 1.3 microns. In
certain embodiments, the sizing emulsion has a median particle size of less than or
equal to 1.5 microns after 0 minutes of aging, less than or equal to 1.5 microns after 30
minutes of aging, and less than or equal to 1.5 microns after 60 minutes of aging.
[0009] In certain embodiments, the ratio of emulsifier to sizing agent ranges from
0.6:1.0 to 1.3:1.0.
[0010] In another aspect, disclosed herein is a method of enhancing sizing, the
method comprising adding an effective amount of a sizing emulsion to a paper machine
in a papermaking process, wherein the sizing emulsion includes a) a sizing agent, b) an
emulsifier, and c) an aqueous component.
[0011] In certain embodiments, the sizing agent is selected from the group
consisting of an alkyl ketene dimer ("AKD") and an alkenyl succinic anhydride (ASA).
[0012] In certain embodiments, the emulsifier is selected from the group consisting
of: glyoxalated poly(DADMAC)/AcAm polymer having a 5 mole DADMAC
monomer content; glyoxalated poly(DADMAC)/AcAm polymer having a 5 mole
DADMAC monomer content and further comprising MgS0 4-7H20 ; glyoxalated
poly(DADMAC)/AcAm polymer having a 12 mole DADMAC monomer content;
and glyoxalated poly(DADMAC)/AcAm polymer having a 12 mole DADMAC
monomer content and further comprising MgS0 4-7H20 . In certain embodiments, the
emulsifier is glyoxalated poly(DADMAC)/AcAm polymer having a 5 mole
DADMAC monomer content. In certain embodiments, the emulsifier is glyoxalated
poly(DADMAC)/AcAm polymer having a 5 mole DADMAC monomer content and
further comprising MgS0 4-7H20 . In certain embodiments, the emulsifier is
glyoxalated poly(DADMAC)/AcAm polymer having a 12 mole DADMAC monomer
content. In certain embodiments, the emulsifier is glyoxalated poly(DADMAC)/AcAm
polymer having a 12 mole% DADMAC monomer content and further comprising
MgS0 4-7H20 .
[0013] In certain embodiments, the sizing emulsion has a median particle size of less
than or equal to 2.5 microns, less than or equal to 2.0 microns, less than or equal to 1.5
microns, less than or equal to 1.4 microns, or less than or equal to 1.3 microns. In
certain embodiments, the sizing emulsion has a median particle size of less than or
equal to 1.5 microns after 0 minutes of aging, less than or equal to 1.5 microns after 30
minutes of aging, and less than or equal to 1.5 microns after 60 minutes of aging.
[0014] In certain embodiments, the ratio of emulsifier to sizing agent ranges from
0.6:1.0 to 1.3:1.0, based on volume.
[0015] In certain embodiments, the sizing emulsion is prepared in a high shear
homogenizer emulsification unit. The volume ratio of emulsifier to ASA may range
from 0.6: 1.0 to 1.0:1.0. The percentage of the emulsifier in the turbine loop may range
from 0.25% to 1.2% based on solids. The resulting sizing emulsion may have a median
particle size (D50) of 1.4 micron or less.
[0016] In certain embodiments, the sizing emulsion is prepared in a high pressure
turbine emulsification unit. The volume ratio of emulsifier to ASA may range from
0.6:1.0 to 1.3:1.0. The percentage of the emulsifier in the turbine loop may range from
0.5% to 1.8% based on solids. The resulting sizing emulsion may have a median
particle size (D50) of 2.3 micron or less.
[0017] In certain embodiments, the sizing emulsion is diluted with a secondary
carrier solution prior or simultaneously to entering a headbox of the paper machine.
The secondary carrier solution may be an aqueous solution comprising an emulsifier.
The emulsifier may be selected from the group consisting of: glyoxalated
poly(DADMAC)/AcAm polymer having a 5 mole% DADMAC monomer content;
glyoxalated poly(DADMAC)/AcAm polymer having a 5 mole% DADMAC monomer
content and further comprising MgS0 4-7H20 ; glyoxalated poly(DADMAC)/AcAm
polymer having a 12 mole% DADMAC monomer content; and glyoxalated
poly(DADMAC)/AcAm polymer having a 12 mole% DADMAC monomer content and
further comprising MgS0 4-7H20 . In certain embodiments, the secondary carrier
solution includes about 2 weight % to about 10 weight % of the emulsifier. In certain
embodiments, the secondary carrier solution is an aqueous solution free of emulsifiers.
In certain embodiments, the ratio of secondary carrier solution added to the sizing
emulsion ranges from 2:1 to 20:1.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 is a graphical representation of the effect of an embodiment of the
invention on reel moisture and steam pressure as a function of time.
[0019] Figure 2 shows Malvern Mastersizer distributions (vol of emulsion
particles with a given diameter) for ASA emulsions prepared with an existing
polymeric emulsifier containing a surfactant and polymers of the invention.
[0020] Figure 3 shows that the sizing effect on laboratory prepared handsheets as
measured by Hercules Sizing Test ("HST") method was unexpectedly better with
glyoxalated polymer emulsion.
[0021] Figure 4 shows sizing performance of GPAM emulsification technology as a
function of emulsifier to ASA ratio and size dose.
[0022] Figure 5 shows sizing performance of GPAM emulsification technology as a
function of emulsifier to ASA ratio and size dose compared to conventional emulsifier
technology.
[0023] Figure 6 shows paper machine trial data using large particle size
GPAM/ASA emulsions.
[0024] Figures 7-10 show sizing efficiency when GPAM and ASA are introduced
into the papermaking process without emulsification.
DETAILED DESCRIPTION
[0025] Disclosed herein are sizing emulsions comprising at least one sizing agent, at
least one emulsifier, and at least one aqueous component. It has been discovered
unexpectedly that when one or more aldehyde-functionalized polymers are used as
emulsifiers in the sizing emulsions, dramatic increases in papermachine dewatering and
increases in paper production are achieved. Additionally, significant increases in
internal sizing are achieved using the disclosed aldehyde-functionalized polymers when
compared with equal amounts of polymer stabilizers consisting of starch or low to
medium molecular weight cationic acrylamide polymers (i.e., sizing emulsion
stabilizers currently used in the papermaking industry).
[0026] Also disclosed herein are methods of preparing sizing emulsions. The
methods provide sizing emulsions exhibiting superior sizing performance compared to
conventional sizing compositions and methods.
1. Definitions
[0027] Unless otherwise defined, all technical and scientific terms used herein have
the same meaning as commonly understood by one of ordinary skill in the art. In case
of conflict, the present document, including definitions, will control. Preferred
methods and materials are described below, although methods and materials similar or
equivalent to those described herein can be used in practice or testing of the present
invention. All publications, patent applications, patents and other references mentioned
herein are incorporated by reference in their entirety. The materials, methods, and
examples disclosed herein are illustrative only and not intended to be limiting.
[0028] The terms "comprise(s)," "include(s)," "having," "has," "can," "contain(s),"
and variants thereof, as used herein, are intended to be open-ended transitional phrases,
terms, or words that do not preclude the possibility of additional acts or structures. The
singular forms "a," "and" and "the" include plural references unless the context clearly
dictates otherwise. The present disclosure also contemplates other embodiments
"comprising," "consisting of and "consisting essentially of," the embodiments or
elements presented herein, whether explicitly set forth or not.
[0029] The following definitions are intended to be clarifying and are not intended
to be limiting.
[0030] "Acrylamide monomer" means a monomer of formula
Rj O
H2C=C— CNHR2
wherein Ri is H or Ci-C4 alkyl and R2 is H, CrC 4 alkyl, aryl, or arylalkyl. Preferred
acrylamide monomers are acrylamide and methacrylamide. Acrylamide is more
preferred.
[0031] "Aldehyde" means a compound containing one or more aldehyde (-CHO)
groups or a group capable of forming a reactive aldehyde group, where the aldehyde
groups are capable of reacting with the aldehyde-reactive groups (e.g., amino or amido
groups) of a polymer as described herein. Representative aldehydes include
formaldehyde, paraformaldehyde, glutaraldehyde, glyoxal, the like, and any other
suitable mono-functional or poly-functional aldehyde. Glyoxal is preferred.
[0032] "Aldehyde-functionalized" means the reaction product of a precursor
polymer and an aldehyde, where aldehyde-reactive group(s) of the precursor polymer
has reacted with terminal carbonyl group(s) of the aldehyde(s).
[0033] "Alkyl" means a monovalent group derived from a straight or branched chain
saturated hydrocarbon by the removal of a single hydrogen atom. Representative alkyl
groups include methyl, ethyl, n- and wo-propyl, cetyl, and the like.
[0034] "Alkylene" means a divalent group derived from a straight or branched chain
saturated hydrocarbon by the removal of two hydrogen atoms. Representative alkylene
groups include methylene, ethylene, propylene, and the like.
[0035] "Amido group" means a group of formula -C(0)NHYi where Y is selected
from H, alkyl, aryl, and arylalkyl.
[0036] "Amino group" means a group of formula -NHY 2 where Y2 is selected from
H, alkyl, aryl, and arylalkyl.
[0037] "Amphoteric" means a polymer derived from both cationic monomers and
anionic monomers, and, possibly, other non-ionic monomer(s). Representative
amphoteric polymers include copolymers composed of acrylic acid and
DMAEA MCQ, terpolymers composed of acrylic acid, DADMAC and acrylamide, and
the like.
[0038] "Aryl" means an aromatic monocyclic or multicyclic ring system of about 6
to about 10 carbon atoms. The aryl is optionally substituted with one or more C to C2o
alkyl, alkoxy, or haloalkyl groups. Representative aryl groups include phenyl or
naphthyl, or substituted phenyl or substituted naphthyl.
[0039] "Arylalkyl" means an aryl-alkylene- group where aryl and alkylene are
defined herein. Representative arylalkyl groups include benzyl, phenylethyl,
phenylpropyl, 1-naphthylmethyl, and the like. Benzyl is preferred.
[0040] "Cobb value" of a paper is a measure of the paper's ability to absorb water.
Generally, the Cobb method is carried out such that an area of 100 cm of a paper
specimen during 60 seconds is subjected to influence from water, whereafter excess
water is removed in a prescribed manner. Starting out from the weight of the paper
before and after the exposure, the weight of the absorbed water is determined, which
gives the Cobb value. A high Cobb value means that the water absorption ability is
high and a low Cobb value that the water absorption ability is low.
[0041] "Diallyl-N,N -disubstituted ammonium halide monomer" means a monomer
of the following formula.
wherein R3 and R4 are independently Ci to C20 alkyl, aryl, or arylalkyl and X is an
anionic counterion. Representative anionic counterions include halogen, sulfate,
nitrate, phosphate, and the like. A preferred anionic counterion is halide. Chloride is
preferred. A preferred diallyl-N,N -disubstituted ammonium halide monomer is
diallyldimethylammonium chloride.
[0042] "Dispersion polymer" polymer means a water-soluble polymer dispersed in
an aqueous continuous phase containing one or more organic or inorganic salts and/or
one or more aqueous polymers. Representative examples of dispersion polymerization
of water-soluble polymers in an aqueous continuous phase can be found in U.S. Patent
Nos. 5,605,970; 5,837,776; 5,985,992; 4,929,655; 5,006,590; 5,597,859; and 5,597,858
and in European Patent Nos. 183,466; 657,478; and 630,909.
[0043] "Emulsion" may refer to a liquid mixture in which a dispersed phase liquid,
which is otherwise immiscible within a continuous phase liquid, is effectively
distributed throughout the continuous phase liquid by means of some chemical and/or
process.
[0044] "Emulsion polymer" and "latex polymer" mean a polymer emulsion
comprising an aldehyde-functionalized polymer according to this invention in the
aqueous phase, a hydrocarbon oil for the oil phase and a water-in-oil emulsifying agent.
Inverse emulsion polymers are hydrocarbon continuous with the water-soluble
polymers dispersed within the hydrocarbon matrix. The inverse emulsion polymers are
then "inverted" or activated for use by releasing the polymer from the particles using
shear, dilution, and, generally, another surfactant. See U.S. Pat. No. 3,734,873,
incorporated herein by reference. Representative preparations of high molecular
weight inverse emulsion polymers are described in U. S. Patent nos. 2,982,749;
3,284,393; and 3,734,873. See also, Hunkeler, et al., "Mechanism, Kinetics and
Modeling of the Inverse-Microsuspension Homopolymerization of Acrylamide, "
Polymer, vol. 30(1), pp 127-42 (1989); and Hunkeler et al., "Mechanism, Kinetics and
Modeling of Inverse-Microsuspension Polymerization: 2. Copolymerization of
Acrylamide with Quaternary Ammonium Cationic Monomers, " Polymer, vol. 32(14),
pp 2626-40 (1991).
[0045] "Monomer" means a polymerizable allylic, vinylic, or acrylic compound.
The monomer may be anionic, cationic, nonionic, or zwitterionic. Vinyl monomers are
preferred, and acrylic monomers are more preferred.
[0046] "Papermaking process" means a method of making paper and paperboard
products from pulp comprising forming an aqueous cellulosic papermaking furnish
(optionally, with mineral fillers, such as calcium carbonates, clays, etc.), draining the
furnish to form a sheet, and drying the sheet. It should be appreciated that any suitable
furnish may be used. Representative furnishes include, for example, virgin pulp,
recycled pulp, kraft pulp (bleached and unbleached), sulfite pulp, mechanical pulp,
polymeric plastic fibers, the like, any combination of the foregoing pulps. The steps of
forming the papermaking furnish, draining and drying may be carried out in any
manner generally known to those skilled in the art. In addition to the sizing emulsions
herein described, other papermaking additives may be utilized as adjuncts with the
polymer treatment of this invention, though it must be emphasized that no adjunct is
required for effective activity. Such papermaking additives include, for example,
retention aids (e.g., microparticles, flocculants, polymeric and inorganic coagulants,
etc.), wet and dry strength additives (e.g., cationic starches, polyamidoamine
epichlorohydrin-based polymers), the like, and combinations of the foregoing.
[0047] "Sizing" may refer to a papermaking process for reducing the hydrophilic
nature of cellulose in paper to increase its resistance to penetration by printing or
writing ink.
[0048] "Sizing mixture" or "sizing emulsion" may refer to an emulsion or dispersion
used for sizing.
[0049] "Wet-end" may refer to that portion of a papermaking process involving an
approach system, a sheet forming section and/or a pressing section.
[0050] For the recitation of numeric ranges herein, each intervening number there
between with the same degree of precision is explicitly contemplated. For example, for
the range of 6-9, the numbers 7 and 8 are contemplated in addition to 6 and 9, and for
the range 6.0-7.0, the number 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, and 7.0 are
explicitly contemplated.
2. Sizing Emulsions
[0051] Sizing emulsions disclosed herein, also referred to as "sizing mixtures," or
"emulsified product," include at least one sizing agent, at least one emulsifier, and at
least one aqueous component.
[0052] In certain embodiments, the ratio of sizing agent to emulsifier (sizing agent :
emulsifier) ranges from 1:1 to 20:1, about 2:1 to about 15:1, or about 2.5:1 to about
10:1. Alternatively, in certain embodiments, the ratio may be expressed as emulsifier
to sizing agent (emulsifier : sizing agent), in which case the ratio may range from
0.05:1 to 1:1, about 0.07:1 to about 0.5:1, or about 0.1:1 to about 0.4:1. In certain
embodiments, the ratio of emulsifier to sizing agent (emulsifier : sizing agent) may be
about 0.05:1.00, about 0.10:1.00, about 0.15:1.00, about 0.20:1.00, about 0.25:1.00,
about 0.30:1.00, about 0.35:1.00, about 0.40:1.00, about 0.45:1.00, about 0.50:1.00,
about 0.55:1.00, about 0.60:1.00, about 0.65:1.00, about 0.70:1.00, about 0.75:1.00,
about 0.80:1.00, about 0.85:1.00, about 0.90:1.00, about 0.95:1.00, or about 1.00:1.00.
Ratios are by weight of active ingredients.
[0053] In certain embodiments, the ratio of emulsifier to sizing agent (emulsifier :
sizing agent), on a volume basis, may range from about 0.03:1 to about 1.5:1, about
0.05:1 to about 1.3:1, about 0.05:1 to about 1:1, about 0.07:1 to about 0.5:1, or about
0.1:1 to about 0.4:1. In certain embodiments, the ratio of emulsifier to sizing agent
may range from 0.6:1.0 to 1.25:1.0, 0.6:1.0 to 1.0:1.0, 0.6:1.0 to 0.95:1.0, or 0.6:1.0 to
0.90:1.0, based on volume. In certain embodiments, the ratio of emulsifier to sizing
agent (emulsifier : sizing agent), on a volume basis, may be about 0.05:1.00, about
0.10:1.00, about 0.15:1.00, about 0.20:1.00, about 0.25:1.00, about 0.30:1.00, about
0.35:1.00, about 0.40:1.00, about 0.45:1.00, about 0.50:1.00, about 0.55:1.00, about
0.60:1.00, about 0.65:1.00, about 0.70:1.00, about 0.75:1.00, about 0.80:1.00, about
0.85:1.00, about 0.90:1.00, about 0.95:1.00, about 1.00:1.00, about 1.05:1.00, about
1.10:1.00, about 1.15:1.00, about 1.20:1.00, about 1.25:1.00, about 1.30:1.00, about
1.35:1.00, about 1.40:1.00, about 1.45:1.00, or about 1.50:1.00. Ratios are by volume
of active ingredients.
[0054] In certain embodiments, the sizing emulsions may have a sizing agent
concentration of 0.01 to 40% by weight, and an emulsifier concentration of 0.001%
to 16% by weight. In certain embodiments, the sizing emulsions may have a sizing
agent concentration by weight of about 0.1%, about 0.2%, about 0.3%, about 0.4%,
about 0.5%, about 0.6%, about 0.7%, about 0.8%, about 0.9%, or about 1.0%. In
certain embodiments, the sizing emulsions may have a sizing agent concentration by
weight of about 1%, about 2%, about 3%, about 4%, about 5%, about 6%, about 7%,
about 8%, about 9%, about 10%, about 11%, about 12%, about 13%, about 14%, about
15%, about 16%, about 17%, about 18%, about 19%, about 20%, about 21%, about
22%, about 23%, about 24%, about 25%, about 26%, about 27%, about 28%, about
29%, about 30%, about 31%, about 32%, about 33%, about 34%, about 35%, about
36%, about 37%, about 38%, about 39%, or about 40%.
[0055] In certain embodiments, the sizing emulsions may have an emulsifier
concentration by weight of about 0.01%, about 0.02%, about 0.03%, about 0.04%,
about 0.05%, about 0.06%, about 0.07%, about 0.08%, about 0.09%, or about 0.10%.
In certain embodiments, the sizing emulsions may have a emulsifier concentration by
weight of about 0.1%, about 0.2%, about 0.3%, about 0.4%, about 0.5%, about 0.6%,
about 0.7%, about 0.8%, about 0.9%, or about 1.0%. In certain embodiments, the
sizing emulsions may have an emulsifier concentration by weight of about 1%, about
2%, about 3%, about 4%, about 5%, about 6%, about 7%, about 8%, about 9%, about
10%, about 11%, about 12%, about 13%, about 14%, about 15%, or about 16%.
[0056] The sizing emulsions can be prepared with any particle size suitable for the
intended use. Desired results normally refer to the average particle size and particle
size distribution. The emulsion particle size may refer to the median diameter of a
vol% distribution obtained with a Malvern Mastersizer laser diffraction instrument
(available from Malvern Instruments, Ltd., Malvern, UK). The median is defined as
the diameter where 50% of the particles are greater than this value and 50% are less
than the value. The particle size of the emulsion can be controlled by the amount of
energy and emulsifier added.
[0057] In certain embodiments, the sizing emulsions have a median particle size
(D50) ranging from 0.01 microns to 10 microns, or 0.5 microns to 3 microns. In certain
embodiments, the sizing emulsions have a median particle size (D50) of 0.5 micron, 0.6
micron, 0.7 micron, 0.8 micron, 0.9 micron, 1.0 micron, 1.1 micron, 1.2 micron, 1.3
micron, 1.4 micron, 1.5 micron, 1.6 micron, 1.7 micron, 1.8 micron, 1.9 micron, 2.0
micron, 2.1 micron, 2.2 micron, 2.3 micron, 2.4 micron, 2.5 micron, 2.6 micron, 2.7
micron, 2.8 micron, 2.9, micron, 3.0 micron, 3.1 micron, 3.2 micron, 3.3 micron, 3.4
micron, 3.5 micron, 3.6 micron, 3.7 micron, 3.8 micron, 3.9 micron, 4.0 micron, 4.1
micron, 4.2 micron, 4.3 micron, 4.4 micron, 4.5 micron, 4.6 micron, 4.7 micron, 4.8
micron, 4.9 micron, or 5.0 micron.
[0058] In certain embodiments, the sizing emulsions have a particle size of which
90% of the population is less than, the D90 being 6.0 micron or less, 5.5 micron or less,
5.0 micron or less, 4.5 micron or less, 4.0 micron or less, 3.5 micron or less, 3.0 micron
or less, 2.5 micron or less, 2.0 micron or less, 1.5 micron or less, 1.4 micron or less, 1.3
micron or less, 1.2 micron or less, 1.1 micron or less, 1.0 micron or less, 0.9 micron or
less, or 0.8 micron or less.
[0059] In certain embodiments, the percentage of particles in the sizing emulsion
with size above 2 micrometer is 80% or less, 70% or less, 60% or less, 50% or less,
40% or less, 30% or less, 20% or less, or 10% or less.
[0060] In certain embodiments, the sizing emulsion has a median particle size of less
than or equal to 2.0 microns after 0 minutes of aging, less than or equal to 2.0 microns
after 30 minutes of aging, and less than or equal to 2.0 microns after 60 minutes of
aging. In certain embodiments, the sizing emulsion has a median particle size of less
than or equal to 1.9 microns after 0 minutes of aging, less than or equal to 1.9 microns
after 30 minutes of aging, and less than or equal to 1.9 microns after 60 minutes of
aging. In certain embodiments, the sizing emulsion has a median particle size of less
than or equal to 1.8 microns after 0 minutes of aging, less than or equal to 1.8 microns
after 30 minutes of aging, and less than or equal to 1.8 microns after 60 minutes of
aging. In certain embodiments, the sizing emulsion has a median particle size of less
than or equal to 1.7 microns after 0 minutes of aging, less than or equal to 1.7 microns
after 30 minutes of aging, and less than or equal to 1.7 microns after 60 minutes of
aging. In certain embodiments, the sizing emulsion has a median particle size of less
than or equal to 1.6 microns after 0 minutes of aging, less than or equal to 1.6 microns
after 30 minutes of aging, and less than or equal to 1.6 microns after 60 minutes of
aging. In certain embodiments, the sizing emulsion has a median particle size of less
than or equal to 1.5 microns after 0 minutes of aging, less than or equal to 1.5 microns
after 30 minutes of aging, and less than or equal to 1.5 microns after 60 minutes of
aging. In certain embodiments, the sizing emulsion has a median particle size of less
than or equal to 1.4 microns after 0 minutes of aging, less than or equal to 1.4 microns
after 30 minutes of aging, and less than or equal to 1.4 microns after 60 minutes of
aging. In certain embodiments, the sizing emulsion has a median particle size of less
than or equal to 1.3 microns after 0 minutes of aging, less than or equal to 1.3 microns
after 30 minutes of aging, and less than or equal to 1.3 microns after 60 minutes of
aging. In certain embodiments, the sizing emulsion has a median particle size of less
than or equal to 1.2 microns after 0 minutes of aging, less than or equal to 1.2 microns
after 30 minutes of aging, and less than or equal to 1.2 microns after 60 minutes of
aging.
[0061] In certain embodiments, large particle sizing emulsions can be provided that
exhibit effective sizing properties. In certain embodiments, the sizing emulsions may
have a median particle size (D50) of 10 micron or greater, 25 micron or greater, 50
micron or greater, 75 micron or greater, 100 micron or greater, 125 micron or greater,
150 micron or greater, 175 micron or greater, 200 micron or greater, 225 micron or
greater, 250 micron or greater, 275 micron or greater, 300 micron or greater, 325
micron or greater, or 350 micron or greater, yet provide a Cobb 60 value of 80 or less,
75 or less, 70 or less, 65 or less, 60 or less, 55 or less, 50 or less, 45 or less, 40 or less,
35 or less, 30 or less, 25 or less, 20 or less, 15 or less, or 10 or less.
[0062] The sizing emulsions disclosed herein can be prepared to provide any Cobb
60 value suitable for the intended use. The Cobb 60 value refers to the amount of water
absorption of a treated article. As the Cobb 60 value decreases, sizing performance
improves. In certain embodiments, the sizing emulsions when used in a paperaiaking
process may provide articles with a Cobb 60 value of 80 or less, 75 or less, 70 or less,
65 or less, 60 or less, 55 or less, 50 or less, 45 or less, 40 or less, 35 or less, 30 or less,
25 or less, 20 or less, 15 or less, or 10 or less. In certain embodiments, the sizing
emulsions when used in a paperaiaking process may provide articles with a Cobb 120
value of 80 or less, 75 or less, 70 or less, 65 or less, 60 or less, 55 or less, 50 or less, 45
or less, 40 or less, 35 or less, 30 or less, 25 or less, 20 or less, 15 or less, or 10 or less.
In certain embodiments, the sizing emulsions when used in a paperaiaking process may
provide articles with a Cobb 30-minute value of 120 or less, 115 or less, 110 or less,
105 or less, 100 or less, 95 or less, 90 or less, 85 or less, 80 or less, 75 or less, 70 or
less, 65 or less, 60 or less, 55 or less, 50 or less, 45 or less, 40 or less, 35 or less, 30 or
less, 25 or less, 20 or less, 15 or less, or 10 or less.
[0063] The sizing emulsion disclosed herein can be prepared to provide a boiling
boat test value ranging from 600 -1800s (10-30 min).
a) Sizing Agents
[0064] The sizing emulsions disclosed herein include at least one sizing agent.
Representative sizing agents include rosin size and water-insoluble hydrophobic
cellulose- sizing agents, such as alkyl ketene dimer ("AKD"), alkenyl succinic
anhydride (ASA), and mixtures thereof.
[0065] In certain embodiments, AKD and rosin sizing agents are used as dispersions
(e.g., solid suspended in a liquid medium) rather than an emulsion. Such dispersions
are sometimes used in circumstances where the melting point for certain AKDs and
rosin sizing agents are lower than the use temperature. The dispersions, for example,
may be made by melting and emulsifying the AKD or rosin sizing agent, allowing it to
cool and solidify, and dispersing in a liquid solvent. Thus, in such embodiments, when
the sizing agent is a solid at room temperature converting the solid to a liquid is
typically necessary to form the emulsion.
[0066] In certain embodiments, the sizing agent is alkenyl succinic anhydride
(ASA).
b) Emulsifiers
[0067] The sizing emulsions disclosed herein include at least one emulsifier. The
emulsifier may include one or more aldehyde-functionalized polymers. The aldehydefunctionalized
polymers may have various architectures including linear, branched,
star, block, graft, dendrimer, the like, and any other suitable architecture. The polymers
may include repeating units derived from one or more monomeric species. The
monomeric species may be present in any amount and in any combination in the
polymers.
[0068] The aldehyde-functionalized polymers may have a weight average molecular
weight ranging from 100 kiloDaltons (kD) to 10,000 kD, 200 kD to 5,000 kD, 300 kD
to 3,000 kD, or 500 kD to 2,000 kD. In certain embodiments, the aldehydefunctionalized
polymer have a molecular weight of about 100 kD, about 200 kD, about
300 kD, about 400 kD, about 500 kD, about 600 kD, about 700 kD, about 800 kD,
about 900 kD, about 1,000 kD, about 1,100 kD, about 1,200 kD, about 1,300 kD, about
1,400 kD, about 1,500 kD, about 1,600 kD, about 1,700 kD, about 1,800 kD, about
1,900 kD, about 2,000 kD, about 2,100 kD, about 2,200 kD, about 2,300 kD, about
2,400 kD, about 2,500 kD, about 2,600 kD, about 2,700 kD, about 2,800 kD, about
2,900 kD, or about 3,000 kD.
[0069] The aldehyde-functionalized polymers may have a Brookfield viscosity,
measured in centipoise (cp), ranging from 5 cp to 30 cp, or 10 cp to 25 cp. In certain
embodiments, the aldehyde-functionalized polymer have a Brookfield viscosity of
about 5 cp, about 6 cp, about 7 cp, about 8 cp, about 9 cp, about 10 cp, about 11 cp,
about 12 cp, about 13 cp, about 14 cp, about 15 cp, about 16 cp, about 17 cp, about 18
cp, about 19 cp, about 20 cp, about 2 1 cp, about 22 cp, about 23 cp, about 24 cp, about
25 cp, about 26 cp, about 27 cp, about 28 cp, about 29 cp, or about 30 cp.
[0070] In certain embodiments, the aldehyde-functionalized polymer is a copolymer
comprising about 1 to about 99 mole percent acrylamide monomers and about 95 mole
percent to about 1 mole percent of one or more cationic, anionic, nonionic, or
zwitterionic monomers, or a mixture thereof. Copolymers prepared from nonionic
aldehyde-reactive monomers and cationic monomers preferably have a cationic charge
of about 1 to about 50 mole percent, more preferably from about 1 to about 30 mole
percent. Copolymers prepared from nonionic aldehyde-reactive monomers and anionic
monomers preferably have an anionic charge of about 1 to about 50 mole percent, more
preferably from about 1 to about 30 mole percent. Zwitterionic polymers preferably
comprise 1 to about 95 mole percent, preferably 1 to about 50 mole percent zwitterionic
monomers.
[0071] In certain embodiments, the aldehyde-functionalized polymers are
amphoteric polymers that preferably have an overall positive charge. Preferred
amphoteric polymers are composed of up to about 40 mole percent cationic monomers
and up to about 20 mole percent anionic monomers with the remaining monomers
preferably being aldehyde-reactive monomers. More preferred amphoteric polymers
comprise about 5 to about 10 mole percent cationic monomers and about 0.5 to about 4
mole percent anionic monomers with the remaining monomers preferably being
aldehyde-reactive monomers.
[0072] Representative non-ionic, water-soluble monomers for inclusion in the
aldehyde-functionalized polymers include acrylamide, methacrylamide, N,Ndimethylacrylamide,
N,N-diethylacrylamide, N-isopropylacrylamide, Nvinylformamide,
N-vinylmethylacetamide, N-vinyl pyrrolidone, hydroxyethyl
methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxypropyl
methacrylate, N-t-butylacrylamide, N-methylolacrylamide, vinyl acetate, vinyl alcohol,
and the like.
[0073] Representative anionic monomers for inclusion in the aldehydefunctionalized
polymers include acrylic acid, and its salts, including, but not limited to
sodium acrylate, and ammonium acrylate, methacrylic acid, and it's salts, including, but
not limited to sodium methacrylate, and ammonium methacrylate, 2-acrylamido-2-
methylpropanesulfonic acid (AMPS), the sodium salt of AMPS, sodium vinyl
sulfonate, styrene sulfonate, maleic acid, and it's salts, including, but not limited to the
sodium salt, and ammonium salt, sulfonate, itaconate, sulfopropyl acrylate or
methacrylate or other water-soluble forms of these or other polymerisable carboxylic or
sulphonic acids. Sulfomethylated acrylamide, allyl sulfonate, sodium vinyl sulfonate,
itaconic acid, acrylamidomethylbutanoic acid, fumaric acid, vinylphosphonic acid,
vinylsulfonic acid, allylphosphonic acid, sulfomethylated acrylamide,
phosphonomethylated acrylamide, itaconic anhydride, and the like.
[0074] Representative cationic monomers or mer units for inclusion in the aldehydefunctionalized
polymers include monoallyl amine, diallyl amine, vinyl amine,
dialkylaminoalkyl acrylates and methacrylates and their quaternary or acid salts,
including, but not limited to, dimethylaminoethyl acrylate methyl chloride quaternary
salt (DMAEA'MCQ), dimethylaminoethyl acrylate methyl sulfate quaternary salt,
dimethyaminoethyl acrylate benzyl chloride quaternary salt, dimethylaminoethyl
acrylate sulfuric acid salt, dimethylaminoethyl acrylate hydrochloric acid salt,
dimethylaminoethyl methacrylate methyl chloride quaternary salt, dimethylaminoethyl
methacrylate methyl sulfate quaternary salt, dimethylaminoethyl methacrylate benzyl
chloride quaternary salt, dimethylaminoethyl methacrylate sulfuric acid salt,
dimethylaminoethyl methacrylate hydrochloric acid salt, dialkylaminoalkylacrylamides
or methacrylamides and their quaternary or acid salts such as
acrylamidopropyltrimethylammonium chloride, dimethylaminopropyl acrylamide
methyl sulfate quaternary salt, dimethylaminopropyl acrylamide sulfuric acid salt,
dimethylaminopropyl acrylamide hydrochloric acid salt,
methacrylamidopropyltrimethylammonium chloride, dimethylaminopropyl
methacrylamide methyl sulfate quaternary salt, dimethylaminopropyl methacrylamide
sulfuric acid salt, dimethylaminopropyl methacrylamide hydrochloric acid salt,
diethylaminoethylacrylate, diethylaminoethylmethacrylate, diallyldiethylammonium
chloride and diallyldimethyl ammonium chloride (DADMAC). Alkyl groups are
generally C to C4 alkyl.
[0075] Representative zwitterionic monomers for inclusion in the aldehydefunctionalized
polymers include those that are a polymerizable molecule containing
cationic and anionic (charged) functionality in equal proportions, so that the molecule
is net neutral overall. Specific representative zwitterionic monomers include N,Ndimethyl-
N-acryloyloxyethyl-N-(3-sulfopropyl)-ammonium betaine, N,N-dimethyl-Nacrylamidopropyl-
N-(2-carboxymethyl)-ammonium betaine, N,N-dimethyl-Nacrylamidopropyl-
N-(3-sulfopropyl)-ammonium betaine, N,N-dimethyl-Nacrylamidopropyl-
N-(2-carboxymethyl)-ammonium betaine, 2-(methylthio)ethyl
methacryloyl-S-(sulfopropyl)-sulfonium betaine, 2-[(2-
acryloylethyl)dimethylammonio]ethyl 2-methyl phosphate, 2-(acryloyloxyethyl)-2'-
(trimethylammonium)ethyl phosphate, [(2-acryloylethyl)dimethylammonio]methyl
phosphonic acid, 2-methacryloyloxyethyl phosphorylcholine (MPC), 2-[(3-
acrylamidopropyl)dimethylammonio]ethyl 2'-isopropyl phosphate (AAPI), l-vinyl-3-
(3-sulfopropyl)imidazolium hydroxide, (2-acryloxyethyl) carboxymethyl
methylsulfonium chloride, l-(3-sulfopropyl)-2-vinylpyridinium betaine, N-(4-
sulfobutyl)-N-methyl-N, N-diallylamine ammonium betaine (MDABS), N,N-diallyl-Nmethyl-
N-(2-sulfoethyl) ammonium betaine, and the like.
[0076] In certain embodiments, the disclosed aldehyde-functionalized polymer
compositions comprise from about 10 to about 90 mole percent aldehyde remaining
unreacted. In certain embodiments, the amount of aldehyde that remains unreacted
may range (all ranges in mole percent) from about 10 to about 80, or from about 10 to
about 70, or from about 10 to about 60 mole percent. In other embodiments, the
amount of aldehyde that remains unreacted is greater than about 60 mole percent.
[0077] In certain embodiments, the aldehyde-functionalized polymer is an aldehydefunctionalized
poly(diallyldimethylammonium chloride)-acrylamide polymer, also
referred to as an aldehyde-functionalized poly(DADMAC)-acrylamide polymer or
aldehyde-functionalized poly(DADMAC)/AcAm polymer. In certain embodiments,
the aldehyde-functionalized polymer is a glyoxalated poly(DADMAC)-acrylamide
polymer, also referred to as a GPAM polymer.
[0078] The GPAM polymer may be derived from a DADMAC-acrylamide
backbone having any suitable mole of DADMAC monomer. In certain
embodiments, the GPAM polymer is derived from a DADMAC-acrylamide backbone
having from 1mole to 50 mole DADMAC monomer content, 2 mole to 30
mole DADMAC monomer content, 3 mole to 25 mole DADMAC monomer
content, 4 mole to 20 mole DADMAC monomer content, 5 mole to 15 mole
DADMAC monomer content, 6 mole to 14 mole DADMAC monomer content, 7
mole to 13 mole DADMAC monomer content, or 8 mole to 12 mole
DADMAC monomer content. In certain embodiments, the GPAM polymer is derived
from a DADMAC-acrylamide backbone having 1mole DADMAC monomer
content, 2 mole DADMAC monomer content, 3 mole DADMAC monomer
content, 4 mole DADMAC monomer content, 5 mole DADMAC monomer
content, 6 mole DADMAC monomer content, 7 mole DADMAC monomer
content, 8 mole DADMAC monomer content, 9 mole DADMAC monomer
content 10 mole% DADMAC monomer content, 1 1 mole% DADMAC monomer
content 12 mole% DADMAC monomer content, 13 mole% DADMAC monomer
content 14 mole% DADMAC monomer content, 15 mole% DADMAC monomer
content 16 mole% DADMAC monomer content, 17 mole% DADMAC monomer
content 18 mole% DADMAC monomer content, 19 mole% DADMAC monomer
content 20 mole% DADMAC monomer content, 2 1 mole% DADMAC monomer
content 22 mole% DADMAC monomer content, 23 mole% DADMAC monomer
content 24 mole% DADMAC monomer content, 25 mole% DADMAC monomer
content 26 mole% DADMAC monomer content, 27 mole% DADMAC monomer
content 28 mole% DADMAC monomer content, 29 mole% DADMAC monomer
content, or 30 mole DADMAC monomer content. In certain embodiments, the
GPAM is an aldehyde-functionalized poly(DADMAC)/AcAm polymer having a 12
mole DADMAC monomer content.
[0079] In certain embodiments, the emulsifiers disclosed herein are provided as neat
compositions. In other embodiments, the emulsifiers are provided as solutions having a
percent actives. For example, the emulsifier may be provided as an aqueous solution of
GPAM polymer (e.g., a 12% solution of GPAM).
i) Stability Additives
[0080] In certain embodiments, the emulsifiers disclosed herein include one or more
stability additives. The stability additive may be an inorganic salt, an organic additive,
or a combination thereof. The stability additive may increase the shelf life of the
emulsifier composition by slowing the rate of product gelling. The presence of the
stability additive may also improve emulsion stability. This improved emulsion
stability may improve on-machine sizing performance.
[0081] Suitable salts for inclusion with the emulsifying polymers include, but are
not limited to, alkali metal salts, alkaline earth metal salts, transition metal salts,
hydrates thereof, the like, and any combination of the foregoing. Specific examples of
inorganic salts include MgS0 4 and its hydrated forms (e.g., MgS0 4-7H20), MgCl2 and
its hydrated forms (e.g., MgCl2-6H20), Mg(acetate)2 and its hydrated forms (e.g.,
Mg(OAc)2-4H20), ZnS0 4 and its hydrated forms (e.g., ZnS0 4-7H20), Na2S0 4, NaCl,
(NH4)2S0 4, and any combination of the foregoing. In certain embodiments, the salt is
selected from the group consisting of magnesium sulfate, magnesium sulfate
monohydrate, magnesium sulfate tetrahydrate, magnesium sulfate pentahydrate,
magnesium sulfate hexahydrate, and magnesium sulfate heptahydrate.
[0082] Suitable organic additives for inclusion with emulsifying polymers include,
but are not limited to, diols, triols, polyols, saccharides, the like, and any combination
of the foregoing. Specific examples of organic additives include glycerol,
ethyleneglycol, urea, and any combination of the foregoing.
[0083] The stabilizing additive may be present in any suitable amount. In certain
embodiments, the stabilizing additive is incorporated into the emulsifier composition at
concentrations from about 0.5 weight % to about 15 weight %based on total weight of
the composition. In certain embodiments, the stabilizing additive is present in the
polymer composition at 1wt , 2 wt , 3 wt , 4 wt , 5 wt , 6 wt , 7 wt , 8 wt
, 9 wt , 10 wt , 11wt , 12 wt , 13 wt , 14 wt , or 15 wt %based on total
weight of the composition.
[0084] In a preferred embodiment, the emulsifier is a GPAM polymer composition
further comprising one or more salts. Suitable salts for inclusion with the GPAM
polymers include, but are not limited to, magnesium sulfate, magnesium sulfate
monohydrate, magnesium sulfate tetrahydrate, magnesium sulfate pentahydrate,
magnesium sulfate hexahydrate, and magnesium sulfate heptahydrate. In certain
embodiments, the GPAM is an aldehyde-functionalized poly(DADMAC)/AcAm
polymer having a 5 mole DADMAC monomer content, said polymer composition
further comprising MgS0 4-7H20 . In certain embodiments, the GPAM is an aldehydefunctionalized
poly(DADMAC)/AcAm polymer having a 12 mole DADMAC
monomer content, said polymer composition further comprising MgS0 4-7H20 ,
preferably at concentrations from about 0.5 weight % to about 10 weight % based on
total weight of the composition. In certain embodiments, the MgS0 4-7H20 is present in
the composition at 1wt , 2 wt , 3 wt , 4 wt , 5 wt , 6 wt , 7 wt , 8 wt , 9
wt , 10 wt , 11 wt , 12 wt , 13 wt , 14 wt , or 15 wt % based on total weight
of the composition.
ii) Method of Making Emulsifiers
[0085] The emulsifiers disclosed herein may be prepared by any suitable method. In
certain embodiments, the aldehyde-functionalized polymers disclosed herein are
prepared by reacting a precursor or preformed polymer comprising one or more
aldehyde-reactive moieties (e.g., any combination of amines, amides, and hydroxyls)
with one or more aldehydes. Preferred polymers include those having amino or amido
groups as the aldehyde-reactive moieties. These precursor or preformed polymers may
be derived from any suitable source and synthesized using any suitable method. For
example, the aldehyde-reactive polymers may be formed via emulsion, dispersion, or
solution polymerization and may contain nonionic, cationic, anionic, and zwitterionic
monomeric species with the polymer. Moreover, these monomeric species may be
present in any amount and in any combination in the polymer.
[0086] In certain embodiments, polyamines are prepared by modification of a pre
formed polyamide, for example by hydrolysis of acrylamide-vinylformamide
copolymer using acid or base as described in U.S. Patent Nos. 6,610,209 and
6,426,383.
[0087] In certain embodiments, polyaminoamides may be prepared by direct
amidation of polyalkyl carboxylic acids and transamidation of copolymers containing
carboxylic acid and (meth)acrylamide units as described in U.S. Patent No. 4,919,821.
[0088] In certain embodiments, the preformed polymers are prepared as an emulsion
or latex polymer. For example, the aqueous phase is prepared by mixing together in
water one or more water-soluble monomers, and any polymerization additives such as
inorganic salts, chelants, pH buffers, and the like. The oil phase is prepared by mixing
together an inert hydrocarbon liquid with one or more oil soluble surfactants. The
surfactant mixture should have a low hydrophilic-lypophilic balance (HLB), to ensure
the formation of an oil continuous emulsion. Appropriate surfactants for water-in-oil
emulsion polymerizations, which are commercially available, are compiled in the North
American Edition of McCutcheon' s Emulsifiers & Detergents. The oil phase may need
to be heated to ensure the formation of a homogeneous oil solution. The oil phase is
then charged into a reactor equipped with a mixer, a thermocouple, a nitrogen purge
tube, and a condenser. The aqueous phase is added to the reactor containing the oil
phase with vigorous stirring to form an emulsion.
[0089] The resulting emulsion is heated to the desired temperature, purged with
nitrogen, and a free-radical initiator is added. The reaction mixture is stirred for several
hours under a nitrogen atmosphere at the desired temperature. Upon completion of the
reaction, the water-in-oil emulsion polymer is cooled to room temperature, where any
desired post-polymerization additives, such as antioxidants, or a high HLB surfactant
(as described in U.S. Patent 3,734,873) may be added. Preferably the resulting
emulsion polymer is a free-flowing liquid. An aqueous solution of the water-in-oil
emulsion polymer can be generated by adding a desired amount of the emulsion
polymer to water with vigorous mixing in the presence of a high-HLB surfactant (as
described in U.S. Patent 3,734,873).
[0090] In certain embodiments, the preformed polymer used in the invention may be
a dispersion polymer. In a typical procedure for preparing a dispersion polymer, an
aqueous solution containing one or more inorganic or organic salts, one or more watersoluble
monomers, any polymerization additives such as processing aids, chelants, pH
buffers and a water-soluble stabilizer polymer is charged to a reactor equipped with a
mixer, a thermocouple, a nitrogen purging tube, and a water condenser. The monomer
solution is mixed vigorously, heated to the desired temperature, and then a free radical
initiator is added. The solution is purged with nitrogen while maintaining temperature
and mixing for several hours. After this time, the mixture is cooled to room
temperature, and any post-polymerization additives are charged to the reactor. Water
continuous dispersions of water-soluble polymers are free flowing liquids with product
viscosities generally in the range of about 100 to about 10,000 centipoise, measured at
low shear.
[0091] In certain embodiments, the preformed or precursor polymers used in the
invention are solution polymers. In a typical procedure for preparing solution
polymers, an aqueous solution containing one or more water-soluble monomers and
any additional polymerization additives such as chelants, pH buffers, and the like, is
prepared. This mixture is charged to a reactor equipped with a mixer, a thermocouple,
a nitrogen purging tube and a water condenser. The solution is mixed vigorously,
heated to the desired temperature, and then one or more free radical polymerization
initiators are added. The solution is purged with nitrogen while maintaining
temperature and mixing for several hours. Typically, the viscosity of the solution
increases during this period. After the polymerization is complete, the reactor contents
are cooled to room temperature and then transferred to storage. Solution polymer
viscosities vary widely, and are dependent upon the concentration and molecular
weight and structure of the active polymer component.
[0092] Polymerization reactions are typically initiated by any means which results in
generation of a suitable free-radical. Thermally derived radicals, in which the radical
species results from thermal, homolytic dissociation of an azo, peroxide, hydroperoxide
and perester compound are preferred. Preferred initiators are azo compounds including
2,2'-azobis(2-amidinopropane) dihydrochloride, 2,2'-azobis[2-(2-imidazolin-2-
yl)propane] dihydrochloride, 2,2'-azobis(isobutyronitrile) (AIBN), 2,2'-azobis(2,4-
dimethylvaleronitrile) (AIVN), the like, and combinations thereof. More preferred
initiators include peroxides, such as ammonium persulfate, sodium persulfate, the like,
and combinations thereof.
[0093] In certain embodiments, the polymerization processes can be carried out as a
batch process or in steps. In a representative batch process, all of the monomers are
reacted together, whereas in a step or semi-batch process, a portion of the monomer is
withheld from the main reaction and added over time to affect the compositional drift
of the copolymer or the formation of the dispersion particles. In a continuous process
embodiment, all of the monomer is added over time and affects the compositional drift
differently.
[0094] The polymerization and/or post polymerization reaction conditions are
selected such that the resulting polymer comprising aldehyde-reactive moieties (i.e., the
preformed or precursor polymer) has a molecular weight of at least about 1,000 g/mole,
preferably about 2,000 to about 10,000,000 g/mole. This polymer is then
functionalized by reaction with one or more aldehydes. Suitable aldehydes include any
compound containing one or more aldehyde (-CHO) functional groups (i.e., monofunctional
or poly-functional aldehydes) and having sufficient reactivity to react with
the aldeyhyde-reactive moieties (e.g., amino or amido groups) of the polymer.
Representative aldehydes include formaldehyde, paraformaldehyde, glutaraldehyde,
glyoxal, the like, and any other suitable reactive aldehyde.
[0095] In an embodiment, the aldehyde-functionalized polymer is prepared by
reacting the polyamide or polyamine with one or more aldehydes at a pH between 4 to
12. The total concentration of polymer backbone (i.e., preformed or precursor polymer
having aldehyde-reactive moieties) plus aldehyde may be between about 2 to about 35
weight percent. Generally, an aqueous solution of the polymer backbone is prepared
for better reaction rate control and increased product stability. The pH of the aqueous
polymer backbone solution is increased to between about 4 to about 12. The reaction
temperature is generally about 20 °C to about 80 °C preferably about 20 °C to about 40
°C. An aqueous aldehyde solution is added to the aqueous polymer backbone solution
with good mixing to prevent gel formation. The rate of viscosity increase is monitored
using a Brookfield viscometer to follow the cross-linking reaction. A viscosity increase
of 0.5 cps indicates an increase in polymer molecular weight and an increase in
polymer precursor cross-linking.
[0096] Generally, the desired viscosity increase corresponds to a desired level of
activity which generally reaches a maximum or a point of diminishing activity at a
specific viscosity. The rate of reaction depends on the temperature, total concentration
of polymer and aldehyde, the ratio of aldehyde to amide/amine functional groups, and
pH. Higher rates of glyoxylation (in the case where glyoxal is used as the aldehyde)
are expected when the temperature, total concentration of polymer and aldehyde, the
ratio of aldehyde to amide/amine functional groups or pH is increased. The rate of
reaction can be slowed down by decreasing the total concentration of polymer and
aldehyde, temperature, the ratio of aldehyde to amide/amine functional groups or pH
(to between about 2 to about 3.5). The amount of unreacted aldehyde at the end of the
reaction increases as the ratio of aldehyde to amide/amine functional groups is
increased.
[0097] In a preferred embodiment, the precursor polymer is prepared from a
DADMAC and acrylamide copolymer. Monomers of DADMAC and acrylamide may
be present in weight-to-weight ratios in the precursor polymer ranging from about 5/95
to about 95/5, respectively. This precursor copolymer may have a weight average
molecular weight of about 17,000 g/mole and may be reacted, for example, with
glyoxal. The amount of glyoxal can vary but is usually added to achieve a glyoxal to
acrylamide mole ratio of 0.1 to 1.0. A preferred DADMAC/acrylamide weight-toweight
ratio is 10/90.
[0098] The reaction conditions are preferably selected such that the molar ratio of
aldehyde to aldehyde-reactive moiety is from about 0.05 to about 1.5. This range of
molar ratios may result in a wide range of the aldehyde-reactive moieties of the
precursor polymer being functionalized. For example, from about 0.5 mole percent to
greater than 40 mole percent of the aldehyde-reactive moieties may be functionalized.
Moreover, depending on the particular combination of chosen aldehydes, from about 2
to about 40 percent or more of those reacted moieties may participate in cross-links
through the multifunctional aldehyde. In certain embodiments, 15 mole percent,
preferably at least about 20 mole percent of the amino or amido groups in the polymer
react with the aldehyde to form an aldehyde-functionalized polymer.
[0099] In certain embodiments, the polymers are combined with a stabilizing
additive, such as magnesium sulfate or a hydrate thereof. Addition of one or more
stabilizing agents to the composition results in increased storage time or shelf life. In a
preferred method for increasing storage time for the aldehyde-functionalized polymer
compositions of the invention, one or more stabilizing agents are introduced into the
reaction mixture while the precursor is undergoing aldehyde-functionalization or to the
aldehyde-functionalized product. The added stabilizing agent(s) preferably increase the
storage time as measured relative to a comparable non-stabilized aldehydefunctionalized
polymer. A representative method for measuring stability includes
determining the viscosity of the product until it rapidly increases to the point of gelling
exhibited during an extended storage time relative to a comparable non-stabilized
aldehyde-functionalized polymer.
[00100] In an embodiment, such a method of increasing storage time may include the
steps of (i) preforming the polymer having one or more aldehyde-reactive moieties, (ii)
adding the one or more reactive aldehydes to the preformed polymer, (iii) inducing
reaction between the preformed polymer and the one or more reactive aldehydes to
form the one or more aldehyde-functionalized polymers, and (iv) adding the one or
more stabilizing agents step-wise, batch, semi-batch, continuous, or intermittent at any
time and at any rate before, during, or after the foregoing steps.
[00101] In another embodiment, such a method may include (i) preforming a polymer
having one or more aldehyde-reactive moieties, (ii) adding one or more reactive
aldehydes to the preformed polymer to form a reaction mixture, (iii) adding the one or
more stabilizing agents to the reaction mixture, and (iv) inducing reaction between the
preformed polymer and the one or more reactive aldehydes to form the stabilized
aldehyde-functionalized polymer composition.
[00102] In a further embodiment, such a method may include (i) preforming the
polymer having one or more aldehyde-reactive moieties, (ii) adding the one or more
reactive aldehydes to the preformed polymer, (iii) inducing reaction between the
preformed polymer and the one or more reactive aldehydes to form the one or more
aldehyde-functionalized polymers, and (iv) adding the one or more stabilizing agents to
the aldehyde-functionalized polymers to form the stabilized aldehyde-functionalized
polymer composition.
c) Aqueous Component
[00103] The sizing emulsions disclosed herein include at least one aqueous
component. The aqueous component may be any suitable aqueous phase suitable for
the intended use. In certain embodiments, the aqueous component is selected from the
group consisting of deionized water, tap water, plant water, process waters for
papermaking processes, and any combination thereof. In certain embodiments, the
aqueous component is a starch solution, fresh water, purified process water from a mill,
thin stock water, alum, clarified white water, white water, or any combination thereof.
The aqueous component may include other constituents, and may have varying levels
of hardness. The aqueous component, or a portion thereof, may be supplied from the
emulsifier and/or the sizing agent components, as disclosed herein. For example, the
emulsifier may be provided as an aqueous solution of an aldehyde-functionalized
polymer.
d) Secondary Diluent
[00104] In certain embodiments, the sizing emulsions prepared with a sizing agent, an
emulsifier, and an aqueous component can be further diluted with a secondary solution
(a "secondary carrier solution"). Use of a secondary carrier solution (e.g., a
glyoxalated polyacrylamide aqueous solution) to dilute the emulsified product may
provide several advantages, including, but not limited to, increased paper machine
production rates, lower steam demands on paper machines, increased paper dry
strength, increased paper wet strength, increased resistance to humidity, improved ASA
sizing response, and addressing market needs for humidity board.
[00105] The secondary carrier solution may be an aqueous solution comprising an
aldehyde-functionalized polymer as disclosed herein, such as GPAM. Alternatively,
the secondary carrier solution may be an aqueous solution free of emulsifiers. In
certain embodiments, the secondary carrier solution is an as-received commercial grade
aqueous solution of GPAM. In certain embodiments, the secondary carrier solution is a
diluted aqueous GPAM solution, comprising about 2 weight % to about 10 weight %
GPAM. The ratio of secondary carrier solution added to the sizing emulsion (e.g.,
GPAM emulsified ASA) may range from 2:1 to 20:1.
[00106] Optionally, additional aldehyde-functionalized polymer (e.g., GPAM) can be
added either at the makedown unit with the secondary carrier solution or added after the
secondary solution has diluted the emulsified product. In certain embodiments,
additional GPAM may be added at the point of addition of the sizing emulsion into the
papermaking process. The additional GPAM may be fed into secondary carrier water
with a ratio ranging from 1:1 to 100:1 (WatenGPAM). The ratio of dilution may
depend on the dosage of GPAM and the final concentration of the emulsified product
(e.g., ASA:GPAM emulsion).
[00107] The secondary diluent can be introduced at any point directly after the
emulsion make down up to the injection point of the emulsion to the paper stock. It is
preferred that the secondary diluent be co-mixed with the emulsion at the paper stock
injection point.
3. Methods of Preparing Sizing emulsions
[00108] Stabilized sizing emulsions can be generally prepared using the procedures
taught in colloid science (e.g. S.E. Friberg & S. Jones, "Emulsions" in the
Encyclopedia of Chemical Technology, Vol. 9 (4th edition)). The general concept
consists of imparting energy to a mixture of hydrophobic material (e.g., sizing agent)
and water in the presence of emulsifier (in this case the cationic polymers described
herein) which results in "small" droplets or particles of the hydrophobic material
suspended in the aqueous phase. The mixing can be accomplished in any number of
ways.
[00109] Mechanical means for emulsification, for example, can include high-speed
agitators, mechanical homogenizers, or turbine pumps. Preferably, the equipment is
capable of preparing an emulsion particle size in the range generally between about
0.01 and about 10 microns, preferably between about 0.5 to about 3 microns.
Normally, the emulsion would be prepared from a mixture of the sizing agent, the
emulsifier, and enough water to achieve the desired dilution. As noted in, for example
U.S. Patent Nos. 4,657,946 and 7,455,751, a surfactant of the sorts identified therein
can be added to enhance the emulsification.
[00110] In certain embodiments, when emulsifying ASA with glyoxalated
polyDADMAC-acrylamide (GPAM) polymers, certain emulsion quality specifications
must be met in order to achieve optimal sizing in paper production processes. If these
emulsion quality specifications are not met, all size response on the paper machine can
be lost. Thus, to meet these emulsion specifications, in certain embodiments the
emulsifier to sizing agent ratio (e.g., GPAM to ASA emulsification ratio) must be
tightly controlled within a certain range. Additionally, in certain embodiments, the
concentration of emulsifier (e.g., GPAM) in the turbine/homogenizer loop during
emulsification must also be carefully controlled within a certain range.
[00111] It has been discovered that sizing agent (e.g., ASA) can be emulsified to a
specific particle size distribution that optimizes sizing performance using particular
high shear or high pressure emulsification processes and operating parameters,
disclosed herein. In certain embodiments, a high pressure turbine pump emulsification
unit may be used to prepare the sizing emulsion. In certain embodiments, a high shear
homogenizer emulsification unit may be used to prepare the sizing emulsion.
[00112] In certain embodiments, when using a high pressure turbine pump
emulsification unit to prepare the sizing emulsion, the emulsion should have a
recirculation loop emulsifier (e.g., GPAM) solids concentration of 0.6% to 1.8%, or
0.9% to 1.0%. In certain embodiments, when using a high pressure turbine pump
emulsification unit to prepare the sizing emulsion, the emulsion should have a
recirculation loop emulsifier (e.g., GPAM) solids concentration of 0.6%, 0.7%, 0.8%,
0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7% or 1.8%.
[00113] In certain embodiments, when using a high shear homogenizer emulsification
unit to prepare the sizing emulsion, the emulsion should have a recirculation loop
emulsifier (e.g., GPAM) solids concentration of 0.25% to 1.2%, 0.25% to 0.9%, or
0.25% to 0.5%. In certain embodiments, when using a high shear homogenizer
emulsification unit to prepare the sizing emulsion, the emulsion should have a
recirculation loop emulsifier (e.g., GPAM) solids concentration of 0.20%, 0.25%,
0.30%, 0.35%, 0.40%, 0.45%, 0.50%, 0.55%, 0.60%, 0.65%, 0.70%, 0.75%, 0.80%,
0.85%, 0.90%, 0.95%, 1.00%, 1.05%, 1.10%, 1.15%, or 1.20%.
[00114] In certain embodiments, when using a high pressure turbine pump
emulsification unit, the emulsifier to sizing agent ratio (e.g., GPAM to ASA
emulsification ratio) should range from 0.65:1.0 to 1.3:1.0 on a solids ratio, or from
0.6:1.0 to 1.25:1.0 on a volume ratio. In certain embodiments, when using the high
pressure turbine pump emulsification process, the emulsifier to sizing agent ratio may
be 0.65:1.00, 0.70:1.00, 0.75:1.00, 0.80:1.00, 0.85:1.00, 0.90:1.00, 0.95:1.00, 1.00:1.00,
1.05:1.00, 1.10:1.00, 1.15:1.00, 1.20:1.00, 1.25:1.00, or 1.30:1.00, based on volume. In
a specifically preferred embodiment, when using a high pressure turbine pump
emulsification unit, the emulsifier to ASA volume ratio ranges from 0.6 - 0.95:1.0 with
a percentage of GPAM in the turbine loop of 0.6 - 1.8% (based on solids).
[00115] In certain embodiments, when using a high shear homogenizer emulsification
unit, the emulsifier to sizing agent ratio (e.g., GPAM to ASA emulsification ratio)
should range from 0.6:1.0 to 1.0:1.0, on a volume ratio. In certain embodiments, when
using a high shear homogenizer emulsification process, the emulsifier to sizing agent
ratio may be 0.60:1.00, 0.65:1.00, 0.70:1.00, 0.75:1.00, 0.80:1.00, 0.85:1.00, 0.90:1.00,
0.95:1.00, or 1.00:1.00, based on volume. In a specifically preferred embodiment,
when using a high shear homogenizer emulsification unit, the emulsifier to ASA
volume ratio ranges from 0.6 - 1.0:1.0 with a percentage of GPAM in the turbine loop
of 0.3 - 0.9% (based on solids).
[00116] The higher emulsifier to sizing agent ratios (e.g., 1.30:1.00) are preferably
only used with the high pressure turbine pump emulsification unit, the upper limit for
preparation of sizing emulsions with the high shear homogenizer preferably being
1.00:1.00.
[00117] Preparing a sizing emulsion according to the parameters disclosed for the
high pressure turbine pump emulsification unit can provide sizing emulsions with a
median particle size of 2.5 micron or less, 2.3 micron or less, 2.0 micron or less, 1.9
micron or less, 1.8 micron or less, 1.7 micron or less, 1.6 micron or less, 1.5 micron or
less, 1.4 micron or less, 1.3 micron or less, 1.2 micron or less, 1.1 micron or less, or 1.0
micron or less; and particle size at which 90% of the population is less than (D90) 6.0
micron or less, 5.0 micron or less, 4.0 micron or less, 3.9 micron or less, 3.8 micron or
less, 3.7 micron or less, 3.6 micron or less, or 3.5 micron or less.
[00118] Preparing a sizing emulsion according to the parameters disclosed for the
high shear homogenizer emulsification unit can provide sizing emulsions with a median
particle size of 1.1 micron or less, 1.0 micron or less, 0.9 micron or less, or 0.8 micron
or less; and particle size at which 90% of the population is less than (D90) 2.4 micron or
less, 2.1 micron or less, 2.0 micron or less, 1.9 micron or less, 1.8 micron or less, 1.7
micron or less, 1.6 micron or less, 1.5 micron or less, 1.4 micron or less, 1.3 micron or
less, or 1.2 micron or less.
[00119] The sizing emulsions prepared according to the parameters for the high
pressure turbine pump or the high shear homogenizer can provide sizing efficiencies
expressed in Cobb 60 values of 80 or less, 70 or less, 60 or less, 50 or less, 40 or less,
30 or less, 20 or less, or 10 or less. The sizing emulsions prepared according to the
parameters for the high pressure turbine pump or the high shear homogenizer can
provide sizing efficiencies expressed in values from a boiling boat test of 600- 1800s
(10-30 min).
[00120] In addition, sizing emulsions prepared according to the parameters for the
high pressure turbine pump or the high shear homogenizer can reduce required sizing
agent (e.g., ASA) dosage by 10-50%.
4. Methods of Sizing
[00121] There are many factors that can affect sizing performance on a paper
machine. Some are due to the chemical properties of the furnish or chemical additives
being used to make the paper. Sizing performance can also be affected by the
operational parameters of the paper machine itself. Constant monitoring, adjustment of
paper making conditions along with proper treatment and make down of the sizing
emulsion helps ensure optimal sizing performance.
[00122] For optimal sizing performance, sizing agents such as ASA are preferably
evenly distributed, anchored, and properly oriented on the fiber surface. Retention of
the sizing agent is extremely important as unretained sizing molecules can hinder sizing
performance. Retention efficiency of small particles, including ASA, during the paper
making process is maximized using specific chemical programs in the wet end of the
paper machine. ASA retention efficiency is also greatly affected by the charge demand
of the paper furnish. So as the charge of the system changes due to variability in
furnish components or additives, ASA retention can change and possibly reduce sizing
efficiency. There are also chemicals present in the papermaking process that can
reduce sizing efficiency. They are mainly surface-active materials that act as antisizing
agents, which include defoamers, dye formulations, contaminants from the
pulping process, etc. If these contaminants are not properly removed from the system
or kept at minimal concentration levels, sizing performance can be negatively affected.
In the drying section of the paper machine, ASA is evenly distributed on the fiber
surface via vapor phase transport. Failure to properly dry the sheet or reach certain
elevated temperatures in the drying section can cause a loss of sizing efficiency.
[00123] In addition to paper making conditions on the machine, the treatment of the
sizing emulsion itself and how it is delivered to the machine can effect sizing
efficiency. ASA emulsions readily react with water and can turn into a chemical form
that does not size the sheet optimally. This is referred to as hydrolyzed ASA. In order
to prevent ASA from hydrolyzing and to improve its stability, the sizing emulsion is
preferably maintained at a specified temperature and pH range. The addition point of a
ASA sizing emulsion to a paper making process also varies from machine to machine
based on the properties of the furnish or grade being manufactured. If the emulsion is
not fed properly to the machine, unwanted interactions with chemicals or furnish
components such as calcium carbonate can occur and reduce sizing efficiency.
[00124] The sizing emulsions disclosed herein can be fed to a paper or paperboard
production process as an emulsion containing a solids content as described herein. The
final sizing emulsion is normally fed to the wet end of a paper machine, which can
include thin stock, thick stock, or white water systems. Most typically the sizing
emulsions are fed in the thin stock approach line to a headbox, which also includes a
white water system (e.g., pre-fan pump). Although wet end addition of the sizing
emulsion is the norm, any addition point that can introduce the composition to the final
paper sheet can yield a sized sheet and can be used in implementing a method of the
invention in various embodiments. Examples are disclosed in U.S. Patent Nos.
4,657,946 and 7,455,751.
[00125] In certain embodiments, a mixing chamber is used to introduce the sizing
emulsion into the papermaking process. Examples of such mixing chambers are
disclosed in U.S. Patent Serial No. 11/339,169, "Method and Arrangement for Feeding
Chemicals into a Process Stream," (available from Nalco Company in Naperville, IL)
and the Ultra Turax, model no. UTI-25 (available from IKA® Works, Inc. in
Wilmington, NC). It is envisioned that any suitable reactor or mixing device/chamber
may be utilized in the method of the invention.
[00126] As described above, in certain embodiments, a secondary carrier solution
may be added at various points in the paper making process. The secondary carrier
solution may comprise additional emulsifier (e.g., GPAM). In addition or alternatively
to, additional emulsifier may be added at the point of addition of the sizing emulsion
into the papermaking process. The additional GPAM may be fed into secondary carrier
water with a ratio ranging from 1:1 to 100:1 (WatenGPAM). The ratio of dilution may
depend on the dosage of GPAM and the final concentration of the emulsified product
(e.g., ASA:GPAM emulsion).
5. Examples
[00127] The foregoing may be better understood by reference to the following
examples, which are intended for illustrative purposes and are not intended to limit the
scope of the invention.
Example 1
[00128] In this example, an embodiment of the invention using 5 mol% DADMAC
(Diallyldimethylammonium chloride)/AcAm polymer glyoxalated with a 0.8 mole ratio
of glyoxal to AcAm was used as the emulsion stabilizer (Polymer 1) and compared
against a 10 mol% DMAEM*MCQ (Dimethylammoniumethylmethyacrylated
methylchloride quat)/AcAm (acrylamide) emulsion stabilizer (Polymer 2). The ASA
used in the tests was a commercially available formulation derived from a mixture of
C16 and C18 alkenyl chains (available as N7540 from Nalco Company, Naperville,
Illinois) at a concentration of 100% (typically ASA is available neat) was used for the
following test method.
[00129] Tests were conducted on a dual headbox Fourdrinier paperboard machine
producing about 600 tons/day of linerboard using 100% recycle fiber derived from old
corrugated containers. The test method comprised substituting Polymer 1 in lieu of
Polymer 2 as the emulsion stabilizer for an internal sizing application. The ratio of
Polymer 1 to Polymer 2 was slowly increased, with a ratio of 1:1 occurring at Reel No.
5 ending with 1:0 at Reel No. 8. At Reel No. 11, the ratio was changed to 0:1 (i.e., a
reversion to 100% Polymer 2). The various ratios of polymers were added to the size
turbine on the emulsification skid at the wet end of the papermachine, where the
consistency varied from 0.35-0.90%. The emulsion was fed just after the pressure
screen on the furnish approach to the headbox. Results are shown in Table 1.
Table 1
[00130] Observed from the results in Table 1, was a significant unexpected
improvement in sizing at 100% Polymer 1 (Reel No. 10). In addition, the wet line
appeared to go towards the couch even when sheet at the reel became drier, and the
fiber orientation by Tensile Stiffness Orientation ("TSO") was effected enough to cause
a need for adjustments to the papermachine (e.g., rush to drag, indicating significant
increase in drainage rate). Partial Polymer 1 substitution (Reel No. 5) did not result in
any of the observable effects.
Example 2
[00131] Tests were conducted on a dual headbox Fourdrinier paperboard machine
producing about 600 tons/day of linerboard using 100% recycle fiber derived from old
corrugated containers. In this example, Polymer 1 and Polymer 2 were used and
compared as the emulsion stabilizer as in example 1. Figure 1 graphically illustrates
Reel Moisture and Steam Pressure as a function of time.
[00132] Several unexpected observations were made from the data shown in Figure 1.
The sheet moisture at the reel dropped dramatically from 7.6 to 6.1 wt% in a matter of a
few minutes after switching from Polymer 1 to Polymer 2. Sheet moisture drop was
then recovered automatically through steam reductions from 160 to 153 psi. Top ply
vacuum seal pit level increases were also observed, indicating more effective vacuum
dewatering, and excess bottom ply white overflow increases were observed within a
few minutes, indicating increased forming section dewatering. When the test was
returned to the Polymer 1 emulsion, a nearly immediate reversion of these benefits was
observed. Moreover, CSF (i.e., pulp freeness) tests did not reveal any noticeable
increase in drainage rate when the sizing emulsion having Polymer 2 was added,
indicating this conventional measurement of drainage did not change.
Example 3
[00133] Tests were conducted on a dual headbox Fourdrinier paperboard machine
producing about 600 tons/day of linerboard using 100% recycle fiber derived from old
corrugated containers. It was observed that use of a 5 mol% DADMAC/AcAm
backbone used to prepare Polymer 2 for ASA emulsification resulted in a loss in sizing,
indicating that simple cationic copolymers without aldehyde-functionalization hurt
performance and demonstrating the need for such functionalization in this application.
Example 4
[00134] Tests were conducted on a dual headbox Fourdrinier paperboard machine
producing about 600 tons/day of linerboard using 100% recycle fiber derived from old
corrugated containers. It was observed that addition of Polymer 2 (by itself without
being emulsified with the ASA sizing additive) to the wet end of the papermachine
(e.g., thin stock) actually yields less sizing (as measured by increased Cobb value)
demonstrating that the polymer of the invention must be added as part of the ASA
sizing additive to achieve the demonstrated beneficial sizing results.
Example 5
[00135] It is known that emulsions prepared with smaller particle size and narrower
distributions will yield improved sizing (e.g., U.S. Patent No. 4,657,946; J.C. Roberts,
"Neutral and Alkaline Sizing" in Paper Chemistry, J.C. Roberts, Ed., Chapman and
Hall: New York, 1991). Figure 2 shows Malvern Mastersizer distributions (vol% of
emulsion particles with a given diameter) for ASA emulsions prepared with an existing
polymeric emulsifier containing about 1 wt% of surfactant (e.g., ethoxylated alkyl
phosphate ester) and with the aldehyde-functionalized polymers of the invention. As
indicated in the Figure 2, the median diameter of the emulsion prepared with
glyoxalated DADMAC/AcAm (10/90 wt ratio) with 0.8 glyoxal to AcAm ratio
(Polymer 1) is 78% larger than with the best standard emulsifier (consisting of 19.8
wt% DMAEM*MCQ (dimethylaminoethylmethacrylate methylchloride quat)/AcAm
(acrylamide) (10/90 mole ratio) + 1 wt% surfactant ethoxylated tridecyl alcohol
phosphate ester (Polymer 2). Additionally, the emulsion size greater than 2 microns
diameter is dramatically larger for the emulsion prepared with the glyoxalated polymer.
The size distribution of the glyoxalated polymer prepared emulsion is also seen to be
much broader. Figure 2 also shows that the glyoxalated polymer produced poorer
emulsion as judged by particle size properties.
[00136] Even though the particle size distribution of the ASA emulsion prepared with
glyoxalated polymer was poorer than the emulsion prepared with standard emulsifier,
Figure 3 shows that the sizing effect on laboratory prepared handsheets as measured by
HST method was unexpectedly better with the glyoxalated polymer emulsion, in
contradiction to the accepted belief by those skilled in the art that a better emulsion
yields better sizing. The furnish used in the testing of Figure 3 was recycled board
furnish. The HST test evaluates the sizing (water penetration in the sheet) by optically
measuring the time for a dye solution to penetrate the sheet. In the HST tests
conducted the dye solution also contained 1 wt formic acid. Figure 3 shows the
improved sizing obtained with the ASA emulsions prepared with the particle size
distribution of the ASA emulsion prepared with glyoxalated polymer even though the
emulsion size distribution is poorer than the comparative emulsion.
Example 6
ASA Emulsions Preparation
[00137] This example describes exemplary glyoxalated polyDADMAC-acrylamide
(GPAM) and alkenyl succinic anhydride (ASA) emulsions according to the invention.
The GPAMs varied in both their mole percent backbone levels of
diallyldimethylammonium chloride (DADMAC) and their average molecular weights.
In Table 2, the weight average molecular weight (AVG Mw) and Brookfield viscosity
are provided for GPAM samples comprising (1) 5 mole % DADMAC backbone, (2) 12
mole % DADMAC backbone, and (3) 5 mole % DADMAC backbone with
MgS0 4-7H20 salt. The GPAM samples 119-1 and 119-2 comprising 5 mole %
DADMAC backbone with MgS0 -7H20 salt were prepared by adding 6 wt %
MgS0 4-7H20 prior to glyoxal functionalization.
Table 2
[00138] Sizing emulsions were prepared according to the procedures described
herein. An emulsion comprising 5 mole percent ASA was prepared by mixing 14
grams of ASA, 22 grams of GPAM, and 244 grams of tap water (measured total
hardness of 135 ppm CaC0 3) in an Osterizer® mini-cup blender for two minutes at
room temperature.
[00139] A secondary emulsion comprising 0.172 mole percent ASA was prepared by
mixing the above emulsion with a fresh water source.
Example 7
Emulsion Stability
[00140] Samples of the representative emulsions described in Table 2 were taken
after 2 minutes of mixing and measured for particle size distribution using a laser light
scattering technique after 0, 30, and 60 minutes of aging time at room temperature. The
particle size distributions (relating to emulsion stability) are shown in Table 3.
[00141] Table 3 suggests that emulsion stability decreases with an increase in weight
averaged molecular weight when using GPAM synthesized using a 5 mole percent
DADMAC backbone. For example, a comparison between Sample ID Nos. 112-1 and
112-4 (corresponding to GPAM, five mole percent DADMAC backbones with average
molecular weights of 1000 kD and 2400 kD, respectively) shows that the lower
molecular weight sample exhibits a smaller median volume and a smaller percentage of
particles with size above 2 micrometer (mih) . Table 3 also suggests that emulsion
stability is significantly improved when the emulsion comprises GPAM synthesized
using the higher cationic charge 12 mole % DADMAC backbone, resulting in a product
with a higher cationic charge. For example, comparing Sample ID Nos. 112-2 and 114-
2 together (both of which possess average molecular weights of 1300 (kD)), reveals
that Sample ID No. 114-2 displays a smaller median volume and a smaller percentage
of particles with size above 2 micrometer than Sample ID No. 112-2 at 0, 30 and 60
minutes. When GPAM is synthesized using a 5 mole % DADMAC backbone in the
presence of MgS0 4-7H20 , the emulsion stability is significantly improved over GPAM
synthesized using a 5 mole % DADMAC backbone without MgS0 4-7H20 . For
example, Sample ID No. 119-2 has a median volume of less than one-half the median
volume of Sample ID No. 112-2, and a smaller percentage of particles with size above
2 micrometer.
Table 3
Example 8
Sizing Efficiency
[00142] The emulsions described above in Table 2 were also tested during a field trial
on a paper machine to determine their effect on sizing efficiency in a gypsum board
mill. The GPAM to ASA ratio was 0.6 to 1.0 based on product. ASA flows to the top
and base ply were adjusted accordingly to maintain Cobb sizing targets. Table 4 shows
the ASA usage rates during the trial.
[00143] The data in Table 4 suggests that sizing efficiency improves slightly when
GPAM emulsifier synthesized with a 5 mole % DADMAC backbone contains the
MgS0 4-7H20 salt. Table 4 also suggests the sizing efficiency improves significantly
when the GPAM emulsifier is synthesized with the 12 mole % DADMAC backbone.
Table 4
Example 9
High Shear Process for ASA Emulsification
[00144] GPAM size emulsification trials were conducted on board and packaging
grade machines, which demonstrated how the GPAM emulsified ASA emulsion quality
affected sizing performance.
[00145] Table 5 shows the particle size distribution and sizing performance results of
ASA emulsified with GPAM used to size a white top Kraft linerboard grade. A high
shear homogenizer emulsification unit was used for the trial. Particle size distribution
is presented as D50 (median particle size) and D90 (particle size at which 90% of the
population is less than). As the particle size distribution becomes larger the D90 value
will increase. The vital information in Table 5 is the emulsifier to ASA volume ratio
and GPAM percent in the turbine loop. Varying these parameters impacts particle size
distribution and sizing performance. In this case, sizing performance is indicated by
the Cobb 60 value. This value shows the amount of water absorption after 60 seconds.
As the Cobb 60 value decreases, sizing performance improves. The median emulsion
particle size increases when the emulsifier to ASA volume ratio is lowered from 1.0 to
0.8. This is due to the decreasing GPAM% in the turbine loop, which also results in
lower sizing efficiency indicated by an increase in the Cobb 60 value. While
maintaining an emulsifier to ASA volume ratio of 0.8:1.0, the GPAM% is increased
from 0.35% to 0.52% by removing water from the emulsification process. This results
in smaller median emulsion particle sizes and improves sizing performance as
evidenced by a decrease in Cobb 60 values. Further reduction in the emulsifier to ASA
volume ratio provides an improved median particle size (D50) of the emulsion but
broadens the particle size distribution measured as an increase in D90, which negatively
impacts sizing performance as the Cobb 60 value increases.
[00146] Figure 4 shows the sizing performance results from the paper machine trial
using the GPAM emulsification technology with the high shear homogenizer
emulsification unit. As mentioned previously, sizing performance is determined by the
Cobb 60 value. This Cobb 60 value is controlled on the paper machine by adjusting the
ASA dose. A low ASA dosage is preferred as well as a low emulsifier to ASA ratio.
Each step change in emulsifier to ASA ratio in Figure 4 correlates to the data presented
in Table 5. A significant improvement in sizing performance resulted when the GPAM
chemistry was used to emulsify ASA in place of the conventional emulsifier. This is
demonstrated by the reduction in size dose to meet the target Cobb 60 value. No loss in
performance was observed when lowering the GPAM to ASA emulsification ratio to
0.7:1.0 on a volume basis.
Table 5
[00147] The results from Table 5 and Figure 4 below demonstrate the following:
When emulsifying ASA with GPAM, sizing performance decreases when the emulsion
median particle size increases or the particle size distribution broadens; as the
emulsifier to ASA volume ratio is lowered the percentage of GPAM present in the
turbine loop decreases, which increases the emulsion's median particle size resulting in
a decrease in sizing efficiency; at a fixed emulsifier to ASA ratio, the median particle
size of the emulsion improves as the percentage of GPAM in the turbine loop is
increased. This improves sizing performance on the machine; and at a fixed percentage
of GPAM in the turbine loop, the median particle size increases as the emulsifier to
ASA volume ratio decreases.
[00148] Based on this performance data and results from additional trials it was
determined that the best practice for emulsifying ASA with GPAM using a high shear
homogenizer emulsification unit is an emulsifier to ASA volume ratio of 0.6 - 1.0:1.0
with a percentage of GPAM in the turbine loop of 0.3 - 0.9% (based on solids).
Example 10
High Pressure Process for ASA Emulsification
[00149] GPAM size emulsification trials were conducted on board and packaging
grade machines, which demonstrated how the GPAM emulsified ASA emulsion quality
affected sizing performance.
[00150] Table 6 shows the particle size distribution and emulsification parameters of
a high pressure turbine emulsification unit. This emulsification trial was held at a
gypsum board mill. As mentioned above, particle size distribution is presented as D50
(median particle size) and D90 (particle size at which 90% of the population is less
than). The vital information in Table 6 is the emulsifier to ASA volume ratio and
GPAM% in turbine loop. These parameters are adjusted accordingly to control
emulsion particle size. Optimal particle size is obtained at an emulsifier to ASA ratio
of 0.65 - 1.0:1.0. Independent of the emulsifier to ASA volume ratio, the particle size
is best at a percentage of GPAM in the loop of 1.0%. This data suggests the high
pressure turbine pump emulsification unit has a tighter operating window for GPAM%
in the turbine loop compared to the high shear homogenizer emulsification unit.
Table 6
[00151] Figure 5 shows the sizing performance results of the emulsification trial
using the emulsions shown in Table 6. In Figure 5, sizing performance is shown by the
boiling boat test. An increase in the boiling boat value correlates to an improvement in
sizing performance. The data shows that higher boiling boat values were achieved with
the GPAM emulsification technology (DVP6P007) compared to the conventional
emulsifier (7541) at lower ASA dosages. The data also shows that when using the
GPAM emulsification technology that the boiling boat values decreased as the median
particle size of the emulsion increased.
[00152] When using a high pressure turbine emulsification unit the best practice for
emulsifying ASA with GPAM is an emulsifier to ASA volume ratio of 0.6-1.3:1.0,
more preferably 0.6 - 0.95:1.0, with a percentage of GPAM in the turbine loop of 0.6 -
1.8% (based on solids).
Example 1 1
Sizing Efficiency with Large Particle Size
[00153] Table 7 shows paper machine trial data where GPAM emulsified ASA
produced very large particle size, yet on-machine performance was excellent, as
illustrated by the associated Figure 6 where ASA dosage was significantly reduced.
This was not expected from a particle size that is greater than 50 micron. The mean
diameter in Table 7 is the average diameter of the measured emulsion particles. The
median diameter is the value at which 50% of the measured emulsion particles are
above and 50% are below this diameter. These values give an idea of the particle size
distribution in the emulsion. It is common for those in the paper making industry to
report the median diameter value. The emulsifier and ASA flows are the volumes
being fed to the emulsification unit to make the primary emulsion. These flows are
used to calculate the emulsifier to ASA volume ratio. The data in Table 7 correlates
with sizing performance results shown in Figure 6 and show that an improvement in
ASA sizing efficiency was achieved on the paper machine even with large emulsion
particle sizes. This result was not expected and would not be predicted based on
current industry knowledge.
Table 7
Comparative Example 12
Sizing Efficiency without ASA Emulsification
[00154] Figures 7-10 demonstrate that introduction of GPAM, such as to provide
wet- or dry-strength, and ASA into the papermaking process without emulsification
results in increase in Cobb value and an increase in required ASA flow, and thus a loss
of sizing efficiency.
[00155] Figure 7 shows machine data from a trial which shows that the addition of
the GPAM strength resin caused a loss in sizing performance as indicated by an
increase in top and bottom Cobb values. During the trial, the GPAM dose was lowered
in an effort to meet sizing targets.
[00156] Figure 8 shows machine data from a trial which shows that the addition of
the GPAM strength resin caused a loss in sizing performance as indicated by an
increase in top and bottom Cobb values. During the trial, the ASA dose fed to the top
and bottom plies had to be increased to meet the sizing target. This increase in size
dose correlates with a decrease in GPAM strength resin dose. The timeline for Figure 8
matches that of Figure 7 and shows the ASA dose (flows) during GPAM trial.
[00157] Figure 9 shows lab sizing performance data which shows that when 3 lb/T of
a strength resin (Metrix®) was added to the paper, sizing performance decreased as
indicated by higher Cobb values compared to paper that did not contain 3 lb/T of DSR.
[00158] Figure 10 shows lab sizing performance data which shows that when 3 lb/T
of a strength resin (Metrix®) was added to the paper, sizing performance decreased as
indicated by higher Cobb values compared to paper that did not contain 3 lb/T of DSR.
Cobb values are similar at higher size dosages, which can be a common occurrence
depending on parameters of Cobb test method.
[00159] Any ranges given either in absolute terms or in approximate terms are
intended to encompass both, and any definitions used herein are intended to be
clarifying and not limiting. Notwithstanding that the numerical ranges and parameters
setting forth the broad scope of the invention are approximations, the numerical values
set forth in the specific examples are reported as precisely as possible. Any numerical
value, however, inherently contains certain errors necessarily resulting from the
standard deviation found in their respective testing measurements. Moreover, all
ranges disclosed herein are to be understood to encompass any and all subranges
(including all fractional and whole values) subsumed therein.
[00160] Furthermore, the invention encompasses any and all possible combinations
of some or all of the various embodiments described herein. Any and all patents, patent
applications, scientific papers, and other references cited in this application, as well as
any references cited therein, are hereby incorporated by reference in their entirety. It
should also be understood that various changes and modifications to the presently
preferred embodiments described herein will be apparent to those skilled in the art.
Such changes and modifications can be made without departing from the spirit and
scope of the invention and without diminishing its intended advantages. It is therefore
intended that such changes and modifications be covered by the appended claims.

What is claimed is:
1. A sizing emulsion, comprising:
a) a sizing agent selected from the group consisting of an alkyl ketene dimer
("AKD") and an alkenyl succinic anhydride (ASA);
b) an emulsifier selected from the group consisting of:
glyoxalated poly(DADMAC)/AcAm polymer having a 5 mole DADMAC
monomer content;
glyoxalated poly(DADMAC)/AcAm polymer having a 5 mole DADMAC
monomer content and further comprising MgS0 4-7H20 ;
glyoxalated poly(DADMAC)/AcAm polymer having a 12 mole DADMAC
monomer content; and
glyoxalated poly(DADMAC)/AcAm polymer having a 12 mole DADMAC
monomer content and further comprising MgS0 4-7H20 ; and
c) an aqueous component.
2. The sizing emulsion of claim 1, wherein the emulsifier is glyoxalated
poly(DADMAC)/AcAm polymer having a 5 mole DADMAC monomer content.
3. The sizing emulsion of claim 1, wherein the emulsifier is glyoxalated
poly(DADMAC)/AcAm polymer having a 5 mole DADMAC monomer content and
further comprising MgS0 4-7H20 .
4. The sizing emulsion of claim 1, wherein the emulsifier is glyoxalated
poly(DADMAC)/AcAm polymer having a 12 mole DADMAC monomer content.
5. The sizing emulsion of claim 1, wherein the emulsifier is glyoxalated
poly(DADMAC)/AcAm polymer having a 12 mole DADMAC monomer content and
further comprising MgS0 4-7H20 .
6. The sizing emulsion of claim 1, having a median particle size of less than or
equal to 2.5 microns.
7. The sizing emulsion of claim 1, having a median particle size of less than or
equal to 2.0 microns.
8. The sizing emulsion of claim 1, having a median particle size of less than or
equal to 1.5 microns.
9. The sizing emulsion of claiml, having a median particle size of less than or
equal to 1.4 microns.
10. The sizing emulsion of claim 1, having a median particle size of less than or
equal to 1.3 microns.
11. The sizing emulsion of claim 1, having a median particle size of less than or
equal to 1.5 microns after 0 minutes of aging, less than or equal to 1.5 microns after 30
minutes of aging, and less than or equal to 1.5 microns after 60 minutes of aging.
12. The sizing emulsion of claim 1, wherein the ratio of emulsifier to sizing agent
ranges from 0.6:1.0 to 1.25:1.0, based on volume.
13. A method of enhancing sizing, the method comprising adding an effective
amount of a sizing emulsion to a paper machine in a papermaking process, wherein the
sizing emulsion comprises:
a) a sizing agent selected from the group consisting of an alkyl ketene dimer
("AKD") and an alkenyl succinic anhydride (ASA);
b) an emulsifier selected from the group consisting of:
glyoxalated poly(DADMAC)/AcAm polymer having a 5 mole DADMAC
monomer content;
glyoxalated poly(DADMAC)/AcAm polymer having a 5 mole% DADMAC
monomer content and further comprising MgS0 4-7H20 ;
glyoxalated poly(DADMAC)/AcAm polymer having a 12 mole% DADMAC
monomer content; and
glyoxalated poly(DADMAC)/AcAm polymer having a 12 mole% DADMAC
monomer content and further comprising MgS0 4-7H20 ; and
c) an aqueous component.
14. The method of claim 13, wherein the sizing emulsion is prepared in a high shear
homogenizer emulsification unit and the volume ratio of emulsifier to ASA ranges
from 0.6: 1.0 to 1.0:1.0.
15. The method of claim 14, wherein the high shear homogenizer emulsification
unit comprises a turbine loop, and the percentage of the emulsifier in the turbine loop
ranges from 0.3% to 0.9% based on solids.
16. The method of claim 15, wherein the sizing emulsion has a median particle size
(D50) of 1.1 micron or less.
17. The method of claim 13, wherein the sizing emulsion is prepared in a high
pressure turbine emulsification unit and the volume ratio of emulsifier to ASA ranges
from 0.6: 1.0 to 1.25:1.0.
18. The method of claim 17, wherein the high pressure turbine emulsification unit
comprises a turbine loop, and the percentage of the emulsifier in the turbine loop ranges
from 0.6% to 1.8% based on solids.
19. The method of claim 18, wherein the sizing emulsion has a median particle size
(D50) of 1.3 micron or less.
20. The method of claim 13, wherein the sizing emulsion is diluted with a
secondary carrier solution prior to entering a headbox of the paper machine.
21. The method of claim 20, wherein the secondary carrier solution is an aqueous
solution comprising an emulsifier selected from the group consisting of:
glyoxalated poly(DADMAC)/AcAm polymer having a 5 mole DADMAC
monomer content;
glyoxalated poly(DADMAC)/AcAm polymer having a 5 mole DADMAC
monomer content and further comprising MgS0 4-7H20 ;
glyoxalated poly(DADMAC)/AcAm polymer having a 12 mole DADMAC
monomer content; and
glyoxalated poly(DADMAC)/AcAm polymer having a 12 mole DADMAC
monomer content and further comprising MgS0 4-7H20 .
22. The method of claim 21, wherein the secondary carrier solution comprises about
2 weight % to about 10 weight % of the emulsifier.
23. The method of claim 20, wherein the secondary carrier solution is an aqueous
solution free of emulsifiers.
24. The method of claim 20, wherein the ratio of secondary carrier solution added
to the sizing emulsion ranges from 2:1 to 20:1.