Method of sizing paper using a sizing agent and a polymeric enhancer and paper produced thereof

Paper sizing enhancer that is a polymerization reaction product of a quaternary diallylammonium monomer and a diallylammonium monomer, as well as compositions containing the sizing enhancer and a sizing agent. The method of sizing paper with such paper sizing enhancer compound and a sizing agent provides sized paper with significantly improved sizing property characteristics, and the sized paper exhibits high print quality when used in inkjet printing applications.

FIELD OF THE INVENTION 
This invention relates to paper sizing enhancer compounds, compositions 
containing paper sizing agents and the sizing enhancer compounds, methods 
of using the sizing enhancer compositions and paper made using the sizing 
enhancer compositions. 
BACKGROUND OF THE INVENTION 
In papermaking and paper finishing, a sizing agent is often employed to 
provide desirable characteristics sought in the ultimate paper product. 
Sizing, or sizing property, is a measure of the resistance of a 
manufactured paper or paperboard product to the penetration or wetting by 
an aqueous liquid. Sizing agents are internal additives employed during 
papermaking or external additives employed as coating agents during paper 
finishing that increase this resistance 
Papermaking can be carried out under acidic or alkaline pH conditions, and 
the selection of a sizing agent is usually dependent on the pH used. For 
example, rosin-derived sizing agents are typically used under acidic 
papermaking conditions. Under alkaline pH conditions, which are becoming 
widely used in fine paper manufacturing applications, typical sizing 
agents include alkyl ketene or alkenyl dimers or acid anhydrides such as 
alkenyl succinic anhydrides. 
The sizing properties provided by conventional paper sizing agents may be 
improved by the use of sizing enhancers, also called sizing accelerators 
or promoters. Numerous paper sizing enhancers are known; see, e.g., U.S. 
Pat. No. 3,840,486; U.S. Pat. No. 3,923,745; U.S. Pat. No. 3,957,574; U.S. 
Pat. No. 4,240,935; U.S. Pat. No. 4,279,794; U.S. Pat. No. 4,295,931; U.S. 
Pat. No. 4,317,756; U.S. Pat. No. 4,407,994; U.S. Pat. No. 4,478,682; U.S. 
Pat. No. 4,847,315; and U.S. Pat. No. 4,895,621, all of which are 
incorporated by reference. 
Despite the beneficial sizing properties provided by these prior art paper 
sizing enhancers, there is still great demand for further improvement. Of 
particular interest are new sizing enhancers that would provide more rapid 
rate of development of the sizing property, once the sizing agent is 
applied to the paper, and that permit more efficient use of the sizing 
agent, by reducing the amount of sizing agent required to yield the 
desired sizing property. 
The rate at which the sizing property develops in the sized paper is very 
important. The sizing property is advantageously developed as quickly as 
possible after the sizing agent has been added or applied. It is known 
that the level of size development increases as sized paper is dried to 
remove moisture. As the rate of size development is increased, the drying 
energy requirements ordinarily decrease for a given level of sizing. In 
papermaking processes where the sizing agent is added at the wet end of 
the paper machine, the sized paper is typically dried to about 0.8-2 wt % 
moisture to obtain adequate development of the sizing property before the 
paper reaches the size press; at the end of the size press treatment, the 
paper is typically dried to about 4-6 wt % moisture. 
If the sizing property is not fully developed, corrective measures must be 
taken, e.g., the paper must be stored for sufficient time (hours or days) 
until the sizing property develops adequately for the intended use of the 
paper, or an excess of sizing agent must be used to provide adequate 
sizing property if the benefit is required (e.g., during the paper 
finishing or converting steps) before the sizing property has completely 
developed. 
The efficiency of the sizing agent, i.e., the degree of sizing obtained per 
unit of size added, is likewise important Improved sizing agent efficiency 
results in improved papermaking economies. Excess sizing agent can 
adversely affect the paper handling characteristics and production 
efficiency during further converting operations performed on the paper 
(i.e., causing jams, misregisters, missed folds, sliding, slipping). 
Excess sizing can also result in significant decreases in the paper 
quality by creating deposits on the paper. 
Various cationic polymers have been described in the prior art for use in 
papermaking, and some of these polymers have been used as paper sizing 
agents or paper sizing enhancers; see, e.g., German Patent 3,635,954, 
which is incorporated by reference. 
Cationic polymers and copolymers based on the cyclopolymerization of 
dimethyldiallylammonium chloride are well known for use in a wide variety 
of industrial applications. A good review of such cationic polymers and 
their uses is Butler, "Practical Significance of Cyclopolymerization," 
Chapter 12 in Cyclopolymerization and Cyclocopolymerization, Marcel 
Dekker, Inc., New York, N.Y., pp. 485-536 (1992), which is incorporated by 
reference. 
Poly(diallyldimethylammonium chloride) homopolymers are well known cationic 
polymeric compounds that have been used commercially in papermaking for a 
wide variety of purposes, e.g., for aiding furnish retention and additive 
retention in paper; for increasing the dewatering rate of wet paper web; 
for neutralizing anionic materials in white water; and for size 
enhancement, to improve paper sizing efficiency and its rate of 
development. Reten.RTM.203 retention aid (Hercules Incorporated, 
Wilmington, Del.), a product which contains a diallyldimethylammonium 
chloride homopolymer, is one such product. 
Poly(diallylammonium chloride) homopolymers are also known cationic 
polymeric compounds that have been reported to be useful for various 
papermaking applications. 
Copolymers and terpolymers containing diallylamine-type compounds, such as 
diallyldimethylammonium chloride (DADMAC) or diallylamine (also referred 
to as DAA), such as diallylammonium chloride (also referred to as DAA.HCl 
or DAAC), as one of the monomeric components are also known. Japanese 
Patent 57 161197, which is incorporated by reference, discloses use of 
copolymers of sulfur dioxide and diallyldialkylammonium salts, such as 
DADMAC, or diallylammonium salts, as a dispersing agent with a paper 
sizing agent. European Patent 282 081, which is incorporated by reference, 
discloses (meth)acrylamide terpolymers that also contain DADMAC or 
diallylamine, useful in combination with aluminum sulfate for increasing 
paper strength. Japanese Patent 52 47883, which is incorporated by 
reference, discloses copolymers of acrylamide and diallylamine-type 
compounds, useful for producing stronger paper. U.S. Pat. Nos. 4,279,794 
and 4,295,931, which are incorporated by reference, disclose the use of 
poly(diallylamine) epihalohydrin resins as paper sizing accelerators. 
Japanese Patent 62 99494, which is incorporated by reference, discloses 
use of copolymers of diallylammonium salts and certain non-ionic 
water-soluble monomers (e.g. acrylamide) with a paper sizing agent to 
provide improved sizing property development. 
Reports in the literature of copolymers containing DADMAC and DAAC are 
relatively isolated, especially when viewed in the context of the huge 
volume of literature concerning DADMAC-based polymers. Japanese Patent 57 
011288, which is incorporated by reference, discloses a printing method 
for cellulose that utilizes a variety of diallyl-based homopolymers or 
copolymers of diallyldialkylammonium salts and diallylammonium salts, but 
the molecular weights of these water-soluble polymers are less than 
10,000. Japanese Patent 61 133213, which is incorporated by reference, 
discloses copolymers useful in textile dying processes and exemplifies 
copolymers that are prepared from DADMAC and DAAC monomers; the disclosed 
copolymers have average molecular weights of 181,000 or less. Japanese 
Patent 59 036788, which is incorporated by reference, discloses a method 
for improving wet fastness in dyed cellulose textile fiber and exemplifies 
the use of homopolymers, copolymers or terpolymers that are made from any 
of several monomers which include diallyldimethylammonium salts. U.S. Pat. 
No. 4,347,339, which is incorporated by reference, discloses DADMAC and 
DAAC copolymers that are reacted with compounds such as epichlorohydrin or 
trichlorotriazine to make cationic block copolymers. 
Despite the reported usefulness of diallyl-based cationic polymers for a 
variety of industrial purposes, there is no suggestion in the prior art of 
the usefulness of copolymers of diallyldialkylammonium salts and 
diallylammonium salts for improving the sizing property characteristics of 
sized paper. 
SUMMARY OF THE INVENTION 
One aspect of the present invention is a paper sizing enhancer that is a 
polymerization reaction product of at least one quaternary diallylammonium 
monomer and at least one diallylammonium monomer. A preferred paper sizing 
enhancer is a polymerization reaction product of a quaternary 
diallylammonium monomer of formula (I): 
##STR1## 
and a diallylammonium monomer of formula (II): 
##STR2## 
where R.sub.1A, R.sub.1B, R.sub.1C and R.sub.1D are independently hydrogen 
or C.sub.1 -C.sub.22 straight chain or branched alkyl; R.sub.2 and R.sub.3 
are independently alkyl, alkenyl, or aryl; R.sub.4 is hydrogen, alkyl, 
alkenyl, or aryl; and X.sup.- is a monovalent anion or a multivalent 
equivalent of a monovalent anion. 
Another aspect of the invention is a paper sizing composition comprising a 
paper sizing agent and the above-described paper sizing enhancer regarding 
the first aspect of this invention. 
Still another aspect of the invention is a method of producing sized paper 
with enhanced sizing property characteristics by employing the paper 
sizing enhancer of this invention. 
Yet another aspect of the invention is sized paper containing the paper 
sizing enhancer of this invention. 
Among the benefits of the present invention, the sizing enhancers increase 
the efficiency of paper sizing agents and increase the rate at which the 
sizing property develops in paper when the sizing enhancers are used with 
sizing agents. Sized paper made with the sizing enhancer of this invention 
exhibits an accelerated rate of sizing property development, requires the 
use of less sizing agent, retains the sizing property longer than papers 
made without the sizing enhancer, and is particularly well suited for 
inkjet printing applications. Other benefits and advantages of the present 
invention will be apparent in view of this disclosure. 
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The references in this specification to "paper" and "papermaking" are 
intended to cover not only paper (and its manufacture), but also 
paperboard, molded paper and other similar cellulosic-web based materials 
(and their manufacture), that are typically manufactured with papermaking 
equipment and procedures and that require additives such as sizing agents 
for modification of the sizing property of the resultant product. 
The paper sizing enhancer of this invention is a polymerization reaction 
product prepared from at least one quaternary diallylammonium monomer and 
at least one diallylammonium monomer. The polymerization reaction product 
is preferably prepared from the monomers: 
(i) quaternary diallylammonium monomer of formula (I), 
##STR3## 
and (ii) diallylammonium monomer of formula (II) 
##STR4## 
In formulas (I) and (II), the R.sub.1 radicals R.sub.1A, R.sub.1B, R.sub.1C 
and R.sub.1D are each independently either hydrogen or methyl. The R.sub.1 
radicals are preferably hydrogen. 
In formula (I), R.sub.2 is alkyl, alkenyl or aryl, preferably C.sub.1 
-C.sub.22 alkyl, C.sub.1 -C.sub.22 alkenyl, or C.sub.6 -C.sub.10 aryl. 
Likewise, in formula (II), R.sub.3 is alkyl, alkenyl or aryl, preferably 
C.sub.1 -C.sub.22 alkyl, C.sub.1 -C.sub.22 alkenyl, or C.sub.6 -C.sub.10 
aryl. 
In formula (II), R.sub.4 is hydrogen, alkyl, alkenyl or aryl, preferably 
hydrogen, C.sub.1 -C.sub.22 alkyl, C.sub.1 -C.sub.22 alkenyl, or C.sub.6 
-C.sub.10 aryl. 
In formulas (I) and (II), the R.sub.2, R.sub.3 and R.sub.4 radicals (other 
than hydrogen) may be unsubstituted or substituted, e.g., alkyl may be 
hydroxyalkyl, carboxy, alkoxy, mercapto or thio. Likewise, in formulas (I) 
and (II), the R.sub.2, R.sub.3 and R.sub.4 alkyl radicals, alkenyl 
radicals and aryl radicals may include ester groups and may be interrupted 
by heteroatoms, e.g., N or S, or by heterogroups, e.g., --NH--CO-- or 
--CO--NH--. 
In formulas (I) and (II), the R.sub.2, R.sub.3 and R.sub.4 alkyl radicals 
and alkenyl radicals may be straight chained or branched. The radicals 
R.sub.2, R.sub.3 and R.sub.4 are preferably uninterrupted alkyl radicals 
with 1-18 carbon atoms, more preferably 1-4 carbon atoms. 
Examples of suitable alkyl radicals for R.sub.2, R.sub.3 and/or R.sub.4 are 
n-docosyl, n-pentadecyl, n-decyl, i-octyl, i-heptyl, n-hexyl, i-pentyl 
and, preferably, n-butyl, i-butyl, sec-butyl, i-propyl, ethyl and methyl. 
The radicals R.sub.2, R.sub.3 and R.sub.4 are preferably identical and are 
preferably methyl. 
Preferred alkenyl groups for the R.sub.2, R.sub.3 and R.sub.4 radicals in 
formulas (I) and (II) include octadecenyl, hexadecenyl, undecenyl, 
octadec-dienyl, hexadec-dienyl, or mixtures of these. Preferred aryl 
groups for R.sub.2, R.sub.3 and R.sub.4 radicals in formulas (I) and (II) 
include benzyl and phenyl. 
In monomers of formula (I), the R.sub.2 and R.sub.3 radicals independently 
are preferably selected from, in decreasing order of preference: methyl, 
benzyl, C.sub.2 -C.sub.18 alkyl, phenyl, octadec-dienyl or hexadec-dienyl, 
octadecenyl or hexadecenyl or undecenyl, and other alkyl and aryl. 
In monomers of formula (II), the R.sub.4 radical is preferably selected 
from, in decreasing order of preference: hydrogen, methyl, benzyl or 
phenyl, C.sub.2 -C.sub.18 alkyl, octadec-dienyl or hexadec-dienyl, 
octadecenyl or hexadecenyl or undecenyl, and other alkyl and aryl. 
In formulas (I) and (II), X.sup.- is a monovalent anion or a multivalent 
equivalent of a monovalent anion. Salts of inorganic acids and common 
organic acids may be used. Preferably, X.sup.- is selected from halide, 
nitrate, acetate, benzoate, sulfate or phosphate. Preferred halides are 
chloride, fluoride and bromide. More preferably, X.sup.- is chloride or 
fluoride. 
More preferred monomers of formulas (I) and (II) are those in which 
R.sub.1A, R.sub.1B, R.sub.1C and R.sub.1D and R.sub.4 are hydrogen and 
R.sub.2 and R.sub.3 are methyl. For such preferred monomers where X.sup.- 
is chloride, the monomer of formula (I) is diallyldimethylammonium 
chloride, sometimes referred to herein as DADMAC, and the monomer of 
formula (II) is diallylammonium chloride, sometimes referred to herein as 
DAA.HCl. 
The polymeric reaction products of the polymerization of monomer of formula 
(I) and monomer of formula (II) preferably contain only these monomeric 
components in the polymer; they do not contain significant amounts of 
other monomeric components in addition to the formula (I) monomer and 
formula (II) monomer. The polymers may contain from about 1 mole % to 
about 99 mole % of the monomer of formula (I), the balance being 
substantially the monomer of formula (II) 
Other monomeric components, however, may be present in addition to the 
formula (I) monomer and formula (II) monomer without adversely affecting 
the sizing enhancer properties of the polymerization reaction product. 
In addition, more than one type or species of formula (I) monomer and/or of 
formula (II) monomer may be employed concurrently in the polymerization 
reaction. 
Preferred compositions of the polymerization reaction products contain from 
about 20 mole % to about 98 mole % monomer of formula (I), the balance 
being substantially monomer of formula (II). More preferred compositions 
contain from about 60 mole % to about 95 mole % of monomer of formula (I), 
the balance being substantially monomer of formula (II); and the most 
preferred compositions contain from about 75 mole % to about 90 mole % 
monomer of formula (I), the balance being substantially monomer of formula 
(II). 
The polymerization reaction products of this invention are water-soluble 
polymers that possess relatively high average molecular weights. The 
weight average molecular weight (M.sub.w) for these polymers is at least 
about 10,000, more preferably at least about 50,000 and most preferably at 
least about 200,000 to about 1,000,000 or more. The performance of these 
polymers as size enhancers improves as their weight average molecular 
weight is increased above about 10,000. For this reason, weight average 
molecular weights of at least about 200,000 to about 1,000,000 or more are 
most preferred. 
The monomeric components utilized for preparation of the polymerization 
reaction products of this invention are either known and are available 
commercially (e.g., DADMAC from CPS Chemical Company, Inc. (Old Bridge, 
N.J.) and from Pearl River Polymers (Pearl River, La.); DADMAC and DAA.HCl 
from Sigma Chemical Company (St. Louis, Mo.)) or may be prepared by 
conventional processes, typically used for the preparation of diallyl-type 
compounds. 
The preparation of the polymeric reaction product is preferably carried out 
by the polymerization of the monomers of formulas (I) and (II) in the 
presence of a free radical polymerization initiator. 
The polymerization reaction of the two diallyl-type monomer components is 
carried out in a suitable solvent, polar solvents being preferred. Water 
is a particularly preferred solvent for the polymerization reaction. Other 
polar solvents which do not adversely affect the polymerization reaction 
may also be used and include lower alcohols such as methanol, ethanol and 
isopropanol (i-propanol), t-butanol, acetone, formamide, 
dimethylformamide, dimethylsulfoxide, and the like. One factor to be 
considered in the selection of a suitable solvent is the potential for 
reaction between the initiator employed and the solvent, causing the 
polymerization reaction to be quenched 
Suitable solvents also include water mixed with a water-miscible solvent or 
solvents. Preferably, such water/water-miscible solvent combinations 
include up to 20% by weight of a water-miscible solvent. Suitable 
water-miscible solvents are, for example, lower alcohols, such as 
methanol, ethanol, n-propanol, i-propanol, n-butanol and t-butanol; 
glycols and diols, such as, for example, ethylene glycol, propylene glycol 
and 1,3-propanediol; di- and polyglycols, such as, for example, diethylene 
glycol and triethylene glycol; glycol ethers, such as, for example, 
diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, 
ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 
ethylene glycol mono-n-propyl ether, ethylene glycol mono-n-butyl ether, 
ethylene glycol dimethyl ether and ethylene glycol diethyl ether; and 
ketones, such as, for example, acetone or methyl ethyl ketone. Water mixed 
with alcohols, in particular those with 1 to 4 carbon atoms, and water 
mixed with diols or glycols are preferred. 
The amount of solvent used in the polymerization reaction medium is 
desirably minimized, to provide high concentrations of the monomers in the 
reaction medium. The lower limit for the amount of solvent is generally 
dictated by the need to obtain adequate mixing of the reaction medium 
throughout the polymerization reaction. Since the viscosity of the 
reaction medium normally increases as high molecular weight polymers are 
formed from the monomer components, it may be advantageous to add 
additional solvent during the course of the polymerization reaction to 
adjust the viscosity of the reaction medium. 
Preferably, the concentration of monomeric reactants in the solvent is from 
about 20 to about 70 wt % and more preferably, from about 40 to about 70 
wt %, based on the weight of the reaction medium. 
Before the start of the polymerization, it is advantageous to adjust the pH 
of the reaction medium to bring the pH to a value of about 2 to about 8.5, 
and preferably, about 3 to about 6. An acid, preferably an inorganic acid 
such as a hydrohalo acid like HCl, is typically used for this adjustment 
of the pH. 
The polymerization reaction temperature employed is normally based on the 
performance characteristics of the initiator used and is also dictated by 
the rate of polymerization and degree of polymerization (molecular weight) 
desired. The polymerization is typically carried out at a temperature of 
about 40.degree. C. to about 100.degree. C., preferably about 50.degree. 
C. to about 95.degree. C. and more preferably at a temperature of about 
70.degree. C. to about 90.degree. C., at ambient pressure (one 
atmosphere). The polymerization reaction is ordinarily characterized by 
being very exothermic in its early stages. The polymerization may require 
from about 30 minutes to many hours, e.g., from about 2 to 30 hours, to 
ensure relatively complete reaction of the monomer components. 
The polymerization reaction of the monomer components is started in the 
customary manner, typically by addition of a suitable initiator, 
preferably one that is water-soluble. 
Preferably, ammonium persulfate, t-butyl hydroperoxide, 
2,2'-azobis-(2-amidinopropane) dihydrochloride, 
2,2'-azobis-(2-imidazol-2-yl-propane) dihydrochloride, 
2,2'-azobis-(2-carbamoylpropane) dihydrate or 
2,2'-azobis-(2-methoxycarbonylpropane) is used as the initiator. 
Other suitable initiators, i.e., substances which form free radicals, 
include hydrogen peroxide, benzoyl peroxide, cumene hydroperoxide, methyl 
ethyl ketone peroxide, lauryl peroxide, t-butyl perbenzoate, di-t-butyl 
perphthalate, azobisisobutyronitrile, 
2,2'-azobis-(2,4-dimethylvaleronitrile), 
2-phenyl-azo-2,4-dimethyl-4-methoxyvaleronitrile, 
2-cyano-2-propylazoformamide, azodiisobutyramide, dimethyl, diethyl or 
di-n-butyl azobismethylvalerate, t-butyl perneodecanoate, di-isononanoyl 
peroxide, t-amyl perpivalate, di-2-ethyl-hexyl peroxydicarbonate, 
dilauroyl peroxide, di-isotridecyl peroxydicarbonate, t-butyl 
peroxyisopropyl percarbonate. Combinations or mixtures of initiators may 
also be used. 
About 0.01 to about 10% by weight, preferably about 0.1 to about 5% by 
weight, of initiator is used, based on the amount (weight) of the monomer 
components. It is advantageous to carry out the polymerization with the 
exclusion of oxygen, to minimize the amount of initiator used and to 
maximize the polymer molecular weight. This can be effected in a 
conventional manner, for example, by flushing or degassing with an inert 
gas, such as nitrogen or argon. The initiator may be added at the outset 
of the reaction or, alternatively, may be added continuously or in 
aliquots during the course of the polymerization reaction, until the 
majority of the monomer components are consumed. Utilization of the 
monomer components, including their rate of consumption, during the 
polymerization may be monitored by carbon 13 NMR or liquid chromatography. 
The two monomers defined by formula (I) and formula (II) are employed in 
relative amounts such that the polymerization reaction product contains 
the desired molar ratio of formula (I) monomer component and formula (II) 
monomer component, within the preferred ranges as described earlier. In an 
exemplary polymerization, the reaction mixture may be prepared by 
dissolving about 0.25 to about 25 parts by weight of formula (I) monomer 
component and about 25 to about 0.25 parts by weight of formula (II) 
monomer component (the total of the two monomer components being about 5 
to about 75 parts by weight, and more preferably, about 40 to about 70 
parts per weight) and about 0.1 to about 5 parts by weight of initiator, 
in about 35 to about 95 parts by weight of a solvent, such as water. 
The average weight molecular weight (Mw) of the polymer reaction product 
may be determined by conventional methods, such as aqueous size exclusion 
chromatography, using, e.g., a polyethylene oxide/polyethylene glycol 
standard calibration. In the Examples described below, size exclusion 
chromatography was performed using a 0.4M lithium acetate and 2.0% 
ethylene glycol (pH 4.5) mobile phase at 0.25 mL/minute flow rate, with a 
Synchrom DATSEC column set (4000+1000+300+100 columns in series). 
The polymerization reaction product of this invention is a water-soluble 
polymer and consequently may be utilized as an aqueous solution or 
dispersion thereof. As described in more detail below, such aqueous 
solutions of the polymerization reaction product may be employed as a 
paper sizing enhancer in the manufacture of sized paper and may optionally 
contain the sizing agent in the aqueous medium. 
The polymerization reaction products of this invention serve as highly 
effective paper sizing enhancers in combination with conventional 
papermaking sizing agents. For papermaking carried out under alkaline pH 
manufacturing conditions, sizing agents based on alkyl or alkenyl ketene 
dimers or multimers and alkenyl succinic anhydride sizing agents are 
preferred. For traditional acid pH papermaking conditions, rosin-derived 
sizing agents are typically used. Combinations of these and other paper 
sizing agents may also be employed. 
These and other hydrophobic sizing agents are well known in the art, and a 
wide variety of such sizing agents may be employed in combination with the 
paper sizing enhancer of this invention. Paper sizing agents are usually 
employed as aqueous emulsions, aqueous dispersions or aqueous solutions. 
The term "emulsion" is used herein, as is customary in the art, to mean 
either a dispersion of the liquid-in-liquid type or of the solid-in-liquid 
type. 
Ketene dimers used as paper sizing agents are well known. Alkyl ketene 
dimers, containing one .beta.-lactone ring, are typically prepared by the 
dimerization of alkyl ketenes made from two fatty acid chlorides. 
Commercial alkyl ketene dimer sizing agents are often prepared from 
palmitic and/or stearic fatty acids, e.g., Hercon.RTM. sizing agents 
(Hercules Incorporated, Wilmington, Del.). 
Alkenyl ketene dimer sizing agents are also commercially available, e.g., 
Aquapel.RTM. sizing agents (Hercules Incorporated, Wilmington, Del.) and 
Precis.RTM. sizing agents (Hercules Incorporated, Wilmington, Del.). 
Ketene multimers, containing more than one .beta.-lactone ring, may also 
be employed as paper sizing agents, and these may be alkyl or alkenyl 
ketene dimers. 
Ketene dimers used as paper sizing agents are generally dimers having the 
formula 
EQU R.sub.5 CH.dbd.C.dbd.O!.sub.2 
where R.sub.5 is a hydrocarbon radical, such as alkyl having at least 8 
carbon atoms, cycloalkyl having at least 6 carbon atoms, aryl, aralkyl and 
alkaryl. In naming ketene dimers, the radical "R.sub.5 " is named followed 
by "ketene dimer". Thus, decyl ketene dimer is C.sub.10 H.sub.21 
--CH.dbd.C.dbd.O!.sub.2. Examples of ketene dimers include octyl, decyl, 
dodecyl, tetradecyl, hexadecyl, octadecyl, eicosyl, decosyl, tetracosyl, 
phenyl, benzyl, beta-naphthyl and cyclohexyl ketene dimers, as well as the 
ketene dimers prepared from montamic acid, naphthenic acid, 
.DELTA.9,10-decylenic acid, .DELTA.9,10-dodecylenic acid, palmitoleic 
acid, oleic acid, ricinoleic acid, linoleic acid, linolenic acid, and 
eleostearic acid, as well as ketene dimers prepared from naturally 
occurring mixtures of fatty acids, such as those mixtures in coconut oil, 
babassu oil, palm kernel oil, palm oil, olive oil, peanut oil, rapeseed 
oil, beef tallow, lard (leaf) and whale blubber. Mixtures of any of the 
above-named fatty acids with each other may also be used. 
Hydrophobic acid anhydrides useful as sizing agents for paper include: 
(i) rosin anhydride (see U.S. Pat. No. 3,582,464, for example, the 
disclosure of which is incorporated herein by reference); 
(ii) anhydrides having the structure 
##STR5## 
where R.sub.6 is a saturated or unsaturated hydrocarbon radical, the 
hydrocarbon radical being a straight or branched chain alkyl radical, an 
aromatic substituted alkyl radical, or an alkyl substituted aromatic 
radical so long as the hydrocarbon radical contains a total of from about 
14 to about 36 carbon atoms; and 
(iii) cyclic dicarboxylic acid anhydrides, preferably having the structure 
##STR6## 
where R.sub.7 represents a dimethylene or trimethylene radical and where 
R.sub.8 is a hydrocarbon radical containing more than 7 carbon atoms which 
are selected from the group consisting of alkyl, alkenyl, aralkyl or 
aralkenyl. Preferred substituted cyclic dicarboxylic acid anhydrides 
falling within the above formula (IV) are substituted succinic and 
glutaric anhydrides. In formula (III) above each R.sub.6 can be the same 
hydrocarbon radical or each R.sub.6 can be a different hydrocarbon 
radical. 
Specific examples of anhydrides of formula (III) are myristoyl anhydride; 
palmitoyl anhydride; oleoyl anhydride; and stearoyl anhydride. 
Specific examples of anhydrides of formula (IV) are i- and n-octadecenyl 
succinic acid anhydride; i- and n-hexadecenyl succinic acid anhydride; i- 
and n-tetradecenyl succinic acid anhydride; dodecyl succinic acid 
anhydride; decenyl succinic acid anhydride; ectenyl succinic acid 
anhydride; and heptyl glutaric acid anhydride. 
Hydrophobic organic isocyanates, e.g., alkylated isocyanates, are another 
class of compounds used as paper sizing agents that are well known in the 
art. Best results are obtained when the hydrocarbon chains of the 
isocyanates are alkyls that contain at least 12 carbon atoms, preferably 
from 14 to 18 carbon atoms. Such isocyanates include rosin isocyanate; 
dodecyl isocyanate; octadecyl isocyanate; tetradecyl isocyanante; 
hexadecyl isocyanate; eicosyl isocyanate; docosyl isocyanate; 6-ethyldecyl 
isocyanate; 6-phenyldecyl isocyanate; and polyisocyanates such as 
1,18-octadecyl diisocyanate and 1,12-dodecyl diisocyanate, wherein one 
long chain alkyl group serves two isocyanate radicals and imparts 
hydrophobic properties to the molecule as a whole. 
Other conventional paper sizing agents suitable for use in this invention 
include alkyl carbamoyl chlorides, alkylated melamines such as stearylated 
melamines, styrene acrylates and styrene maleic anhydrides. 
The polymerization reaction product may be used as a paper sizing enhancer 
according to this invention via an internal addition method or via a 
surface application (external) method, or via a combination of these 
methods. 
Satisfactory performance of the polymerization reaction product as a sizing 
enhancer is generally obtained regardless of the particular method of 
application employed. 
In the internal addition method, the sizing enhancer is introduced as a 
chemical additive into the paper furnish during the papermaking process. 
The sizing enhancer is introduced in combination with the paper sizing 
agent (or agents), either as separately introduced solutions/dispersions 
or as an aqueous medium containing both components. Separate addition of 
the sizing enhancer and paper sizing agent (or agents) is preferred. Other 
conventional papermaking compounds or additions may also be employed with 
the sizing enhancer and/or sizing agent. 
In the surface application method, the sizing enhancer is ordinarily 
applied as a coating, by conventional coating or spraying techniques, to 
the preformed paper, and the coating is dried. The paper is then coated 
with an appropriate paper sizing agent (or agents) and dried again. 
Alternatively, the paper sizing agent and sizing enhancer may be applied 
in a surface treatment method in a single application, with an aqueous 
coating medium containing paper sizing agent, sizing enhancer and, 
optionally, other conventional components. 
Other optional components, for use in an internal addition method and/or 
surface application method, may include a variety of additives 
conventionally used in papermaking, such as starch, fillers, pulp, 
retention aids, strengthening additives, drainage aids, colorants, optical 
brighteners, defoamers and the like. 
Regardless of the method employed, the polymerization reaction product 
sizing enhancer ("polymer") and the paper sizing agent ("size") should be 
utilized in a respective weight ratio of from about 0.05:1 to about 4:1 
polymer:size; preferably, from about 0.2:1 to about 3:1 polymer:size. The 
higher polymer:size ratios within these ranges are preferred since they 
generally provide better enhancement of the sizing property 
characteristics. 
The paper sizing agent (or agents) is ordinarily used in an amount to 
provide good sizing property characteristics in the paper. Sized paper 
typically contains from about 0.005 to about 1.5 wt %, preferably, from 
about 0.025 to about 0.5 wt % and, more preferably, from about 0.05 to 
about 0.25 wt % paper sizing agent, based on the weight of the dried sized 
paper. 
When the polymerization reaction product of this invention is employed as a 
sizing enhancer in combination with a conventional paper sizing agent, the 
amount of paper sizing agent in the sized paper may be decreased without 
sacrifice of the paper sizing property. The sizing enhancer of this 
invention can also be used in combination with other, conventional sizing 
enhancers or sizing additives. 
Sufficient sizing enhancer should be employed to yield sized paper 
containing the sizing enhancer in an amount of from about 0.002 to about 
0.6 wt %, preferably, from 0.007 to about 0.3 wt %, and, more preferably, 
from about 0.012 to about 0.15 wt %, based on the weight of the dried 
sized paper. 
One advantage of the sizing enhancer of this invention is that the sized 
paper need only be dried to a residual moisture level of from about 8 wt % 
to about 12 wt %, based on the weight of the paper, to provide 
satisfactory sizing property characteristics. Without the sizing enhancer, 
such sized paper typically needs to be dried to a residual moisture level 
of about 4-6 wt % to achieve equivalent sizing property characteristics. 
When dried to such conventionally used moisture levels, sized paper 
employing the sizing enhancer of this invention provides even better 
sizing property characteristics. 
The polymerization reaction product of this invention provides numerous 
other advantages as paper sizing enhancers: 
(1) The rate at which the sizing property develops in sized paper is 
significantly increased with the use of the sizing enhancers described in 
this specification. 
(2) The efficiency of paper sizing agents is also increased with the use of 
these sizing enhancers, permitting lower levels of paper sizing agent to 
be employed without decrease or loss of the desired sizing property in the 
sized paper. By allowing lower amounts of sizing agent, the invention 
alleviates the problems associated with the use of excess sizing agents, 
including paper handling problems (jams, misregisters, missed folds, 
sliding, slipping) and deposits during the papermaking process which 
decreases the paper quality and slows the papermaking production rate. 
(3) Sized paper made with paper sizing agents in combination with these 
sizing enhancers exhibits greatly reduced loss of sizing property over 
time and in many cases, no loss of sizing property in the aged sized 
paper. 
(4) Sized paper produced especially for use in ink jet printing 
applications exhibits increased print quality when the sizing enhancers of 
this invention are utilized with the paper sizing agent. 
Several general procedures applicable to the polymerization reaction 
products of this invention and their use are described below. 
Hercules Size Test 
The sizing property performance in sized paper may be characterized by the 
Hercules Size Test, a well-recognized test for measuring sizing 
performance. The Hercules Size Test is described in Pulp and Paper 
Chemistry and Chemical Technology, J. P. Casey, Ed., Vol. 3, p. 1553-1554 
(1981) and in TAPPI Standard T530. The Hercules Size Test determines the 
degree of water sizing obtained in paper, by measuring the change in 
reflectance of the paper's surface as an aqueous solution of dye 
penetrates from the opposite surface side. The aqueous dye solution, e.g., 
naphthol green dye in 1% formic acid in the Examples described below, is 
contained in a ring on the top surface of the paper, and the change in 
reflectance is measured photoelectrically from the bottom surface. 
Test duration is limited by choosing a convenient end point, e.g., a 
reduction in reflected light of 20%, corresponding to 80% reflectance, in 
the Examples described below. A timer measures the time (in seconds) for 
the end point of the test to be reached. Longer times correlate with 
increased sizing performance, i.e., resistance to water penetration 
increases. Unsized paper will typically fail at 0 seconds, lightly sized 
paper will register times of from about 1 to about 20 seconds, moderately 
sized paper from about 21 to about 150 seconds, and hard sized paper from 
about 151 to about 2000 seconds or more. 
Polymerization Reaction Product General Procedure 
A water-soluble polymer of diallyldimethylammonium chloride (DADMAC) and 
diallylammonium chloride (DAA.HCl) may be prepared by the following 
general procedure. 
An aqueous mixture of the two monomer components is made by adding the 
respective monomer components in water in the appropriate mole ratio 
sought in the polymerization reaction product. The aqueous reaction 
mixture is degassed with an inert gas, such as nitrogen or argon, and 
warmed to a temperature of about 40.degree. to about 100.degree. C., with 
mixing. 
A water-soluble free radical polymerization initiator, such as 2,2'-azobis 
(2-amidinopropane) hydrochloride, is added either in aliquots or 
continuously to the reaction mixture, until the majority of the monomer 
components have been consumed in the polymerization reaction. Water is 
usually added to the reaction mixture during the polymerization reaction 
to prevent the viscosity in the aqueous reaction mixture from becoming 
excessive. The concentration of the monomer components in the aqueous 
reaction mixture should not be dilute, since high concentrations of the 
monomers provide better polymerization results. 
Examples 1-23, described below, are exemplary of this general procedure for 
obtaining the polymerization reaction products of this invention. 
For all of the Examples described below, the sizing property of the paper 
was determined using the Hercules Size Test (as described above) 
immediately after the paper was made and also (in several of the Examples) 
after the paper was aged at 50% relative humidity and at a temperature of 
22.degree. C., for seven days or longer (as noted in the Examples) 
All references in the Examples to "parts" refers to parts by weight.

The invention is illustrated further by the following specific, 
non-limiting Examples. 
EXAMPLE 1 
A water-soluble copolymer of diallyldimethylammonium chloride (DADMAC) and 
diallylammonium chloride (DAA.HCl) was prepared in this Example as 
follows. The monomer mole ratio used in the polymerization reaction 
product was about 8:2 DADMAC:DAA.HCl. 
An aqueous mixture was made by combining 53.8 parts of 65 wt % 
diallyldimethylammonium chloride in water with 14.5 parts of 49.8 wt % 
diallylammonium chloride in water. The aqueous reaction mixture of the two 
monomer components was degassed with nitrogen for 40 minutes and warmed to 
a temperature of 55.degree. C. with stirring. 
A water-soluble free radical polymerization initiator, 4.23 parts of 9.09 
wt % 2,2'-azobis (2-amidinopropane) hydrochloride in degassed water was 
added to the aqueous solution at a rate of 0.4 g/minute. After the 
addition of the initiator was complete, 16.9 parts of degassed water was 
added to reduce the viscosity of the reaction medium, and the mixture was 
maintained at a temperature of about 90.degree. C. 
The following step was carried out three times: 4.23 parts of 9.09 wt % 
2,2'-azobis (2-amidinopropane) hydrochloride in degassed water was added 
rapidly, and the reaction mixture was then stirred for one hour. 
At the end of the third one hour stirring period, analysis of the aqueous 
reaction mixture by carbon 13 NMR indicated that greater than 95% of the 
monomer components had been polymerized. The molecular weight data for the 
polymerization reaction product was determined by aqueous size exclusion 
chromatography (SEC) using a Synchrom DATSEC column set (4000+1000+300+100 
columns in series), with 0.4M lithium acetate and 2.0% ethylene glycol (pH 
4.5) as the mobile phase, at a flow rate of 0.25 mL/minute. These SEC 
measurements determined that the polymerization reaction product had a 
number average molecular weight (Mn) of about 21,700 and a weight average 
molecular weight (Mw) of about 364,000. 
EXAMPLE 2 
Another water-soluble copolymer of diallyldlmethylammonium chloride and 
diallylammonium chloride was prepared, as follows. The monomer mole ratio 
in the polymerization reaction product was about 8:2 DADMAC:DAA.HCl. 
An aqueous mixture was made by combining 53.8 parts of 65 wt % 
diallyldimethylammonium chloride in water with 14.5 parts of 49.8 wt % 
diallylammonium chloride in water. The aqueous reaction mixture of the two 
monomer components was degassed with nitrogen for 40 minutes and warmed to 
a temperature of 55.degree. C. with stirring. 
The polymerization initiator in this Example was 2,2'-azobis 
2-(2-imidazolin-2-yl)propane! dihydrochloride, and 1.95 wt % (based on 
the weight of the monomers) of the initiator in degassed water was added 
at a constant rate to the reaction mixture with stirring over a period of 
29 hours. 
Analysis of the resultant polymerization reaction product via SEC 
measurements (as described in Example 1) determined that the product had a 
Mn of about 63,000 and a Mw of about 482,000 with a polydispersity 
(M.sub.w /M.sub.n) of 7.6. 
EXAMPLE 3 
Yet another water-soluble copolymer of diallyldimethylammonium chloride and 
diallylammonium chloride was prepared, as follows. The monomer mole ratio 
in the polymerization reaction product was about 8:2 DADMAC:DAA.HCl. 
An aqueous mixture was made by combining 69 parts of 60 wt % 
diallyldimethylammonium chloride in water with 17.2 parts of 49.6 wt % 
diallylammonium chloride in water. The aqueous reaction mixture of the two 
components was degassed with nitrogen for 30 minutes and warmed to a 
temperature of 50.degree. C. with stirring. 
A polymerization initiator of 1.04 parts of 10 wt % t-butylhydroperoxide in 
degassed water and 0.75 parts of 7 wt % sodium bisulfite in degassed water 
was added to the reaction mixture at a rate such that the temperature of 
the reaction mixture was maintained below 85.degree. C. After the 
initiator addition was complete, the reaction mixture was maintained at 
about 55.degree.-65.degree. C. for 5 hours, with stirring. 
At the end of this period, analysis of the aqueous reaction mixture by 
carbon 13 NMR indicated that 94% of the monomer components had been 
polymerized. Analysis of the resultant polymerization reaction product via 
SEC measurements (as described in Example 1) determined that the product 
had a M.sub.n of about 15,000 and a M.sub.w of about 68,000 with a 
polydispersity (M.sub.w /M.sub.n) of 4.42 
EXAMPLE 4 
A water-soluble copolymer of diallyldimethylammonium chloride and 
diallylammonium chloride, having a monomer mole ratio of 9:1 
DADMAC:DAA.HCl, was prepared as follows: 
111.9 parts of 65 wt % diallyldimethylammonium chloride in water and 13.4 
parts of 50.0 wt % diallylammonium chloride in water and 27 parts of 
distilled water were warmed to 55.degree. C. while stirring. After 
warming, the solution was degassed with nitrogen for about 30 minutes. 
1.36 parts of 2.2'-azobis(2-amidinopropane) hydrochloride in 10 parts of 
distilled, degassed water were then added. After the initiator addition 
was complete, the mixture was stirred for 2 hours, cooled to 30.degree. C. 
and sparged with air for 30 minutes. SEC measurements determined that the 
product had a weight average molecular weight (M.sub.w) of about 431,000 
with a polydispersity of 5.1. Carbon 13 NMR analysis indicated that 
greater than 79% (mole basis) of the monomers had polymerized. 
EXAMPLE 5 
A water-soluble copolymer of diallyldimethylammonium chloride and 
diallylammonium chloride, having a monomer mole ratio of 7:3 
DADMAC:DAA.HCl, was prepared as follows: 
This Example followed a procedure identical to that of Example 4, except 
94.5 parts of 60 wt % diallyldimethylammonium chloride, 40.0 parts of 50.0 
wt % diallylammonium chloride, 13 parts of distilled water were used. SEC 
measurements determined that the product had a weight average molecular 
weight (M.sub.w) of about 322,000 with a polydispersity of 4.8. Carbon 13 
NMR analysis indicated that greater than 81% (mole basis) of the monomers 
had polymerized. 
EXAMPLE 6 
A water-soluble copolymer of diallyldimethylammonium chloride and 
diallylammonium chloride, having a monomer mole ratio of 8:2 
DADMAC:DAA.HCl, was prepared as follows: 
646.8 parts of 60 wt % diallyldimethylammonium chloride in water and 161.4 
parts of 49.6 wt % diallylammonium chloride in water were degassed with 
nitrogen for about 30 minutes. The degassed solution was warmed to 
70.degree. C. while stirring. After warming, 7.68 parts of 
2,2'-azobis(2-amidinopropane) hydrochloride in 64 parts of distilled, 
degassed water were added at a constant rate over about 23.3 hours. 60.0, 
60.0, 60.0 and 360.0 part aliquots of distilled, degassed water were added 
after about 5, 5.5, 6 and 8 hours, respectively, after beginning the 
addition of the initiator. About one hour after the initiator addition was 
complete, the mixture was blanketed with air. 180 parts of water were 
added and the solution was allowed to cool to ambient temperature. SEC 
measurements determined that the product had a weight average molecular 
weight (M.sub.w) of about 398,000 with a polydispersity of 10.8. Carbon 13 
NMR analysis indicated that greater than 92.5% (mole basis) of the 
monomers had polymerized. 
EXAMPLE 7 
A water-soluble copolymer of diallyldimethylammonium chloride and 
diallylammonium chloride, having a monomer mole ratio of 8.5:1.5 
DADMAC:DAA.HCl, was prepared as follows: 
229.0 parts of 60 wt % diallyldimethylammonium chloride in water and 40.4 
parts of 49.6 wt % diallylammonium chloride in water were degassed with 
nitrogen for about 30 minutes. The degassed solution was warmed to 
70.degree. C. while stirring. After warming, 2.56 parts of 
2,2'-azobis(2-amidinopropane) hydrochloride in 22 parts of distilled, 
degassed water were added at a constant rate over about 24 hours. 50.0, 
60.0, 50.0, 50.0, and 100.0 part aliquots of distilled, degassed water 
were added after about 5.5, 7.0, 7.5, 9.0 and 11 hours, respectively, 
after beginning the addition of the initiator. About one hour after the 
initiator addition was complete, the mixture was blanketed with air and 
allowed to cool to ambient temperature. SEC measurements determined that 
the product had a weight average molecular weight (M.sub.w) of about 
470,000 with a polydispersity of 10.0 Carbon 13 NMR analysis indicated 
that 92% (mole basis) of the monomers had polymerized. 
EXAMPLE 8 
A water-soluble copolymer of diallyldimethylammonium chloride and 
diallylammonium chloride, having a monomer mole ratio of 9:1 
DADMAC:DAA.HCl, was prepared as follows: 
242.5 parts of 60 wt % diallyldimethylammonium chloride in water and 26.9 
parts of 49.6 wt % diallylammonium chloride in water were degassed with 
nitrogen for about 30 minutes. The degassed solution was warmed to 
70.degree. C. while stirring. After warming, 2.56 parts of 
2,2'-azobis(2-amidinopropane) hydrochloride in 22 parts of distilled, 
degassed water were added at a constant rate over about 25 hours 30.0, 
30.0, 100.0, 60.0 and 50.0 part aliquots of distilled, degassed water were 
added after about 4, 5, 6, 7.3 and 9 hours, respectively, after beginning 
the addition of the initiator. About one hour after the initiator addition 
was complete, the mixture was blanketed with air and allowed to cool to 
ambient temperature. SEC measurements determined that the product had a 
weight average molecular weight (M.sub.w) of about 473,000 with a 
polydispersity of 13.8. Carbon 13 NMR analysis indicated that greater than 
93% (mole basis) of the monomers had polymerized. 
EXAMPLE 9 
A water-soluble copolymer of diallyldimethylammonium chloride and 
diallylammonium chloride, having a monomer mole ratio of 6:4 
DADMAC:DAA.HCl, was prepared as follows: 
161.7 parts of 60 wt % diallyldimethylammonium chloride in water and 107.3 
parts of 49.8 wt % diallylammonium chloride in water were degassed with 
nitrogen for about 30 minutes. The degassed solution was warmed to 
70.degree. C. while stirring. After warming, 2.56 parts of 
2,2'-azobis(2-amidinopropane) hydrochloride in 23 parts of distilled, 
degassed water were added at a constant rate over about 29 hours. 150.0 
parts of distilled, degassed water were added after about 7 hours after 
beginning the addition of the initiator. About one hour after the 
initiator addition was complete, the mixture was blanketed with air. SEC 
measurements determined that the product had a weight average molecular 
weight (M.sub.w) of about 414,000 with a polydispersity of 9.7. Carbon 13 
NMR analysis indicated that 90% (mole basis) of the monomers had 
polymerized. 
EXAMPLE 10 
A water-soluble copolymer of diallyldimethylammonium ammonium chloride and 
diallylammonium chloride, having a monomer mole ratio of 8:2 
DADMAC:DAA.HCl, was prepared as follows: 
215.6 parts of 60 wt % diallyldimethylammonium chloride in water and 53.6 
parts of 49.8 wt % diallylammonium chloride in water were degassed with 
nitrogen for about 30 minutes. The degassed solution was warmed to 
70.degree. C. while stirring. After warming, 2.56 parts of 
2,2'-azobis(2-amidinopropane) hydrochloride in 23 parts of distilled, 
degassed water were added at a constant rate over about 27.23 hours. 62.5, 
62.0, 62.0 and 80.0 part aliquots of distilled, degassed water were added 
after about 4.3, 5.5, 6.5 and 9 hours, respectively, after beginning the 
addition of the initiator. About one hour after the initiator addition was 
complete, the mixture was blanketed with air and allowed to cool to 
ambient temperature. SEC measurements determined that the product had a 
weight average molecular weight (M.sub.w) of about 424,000 with a 
polydispersity of 11.4. Carbon 13 NMR analysis indicated that 91% (mole 
basis) of the monomers had polymerized. 
Comparative Example 11 
A homopolymer of diallyldimethylammonium chloride (100:0 mole ration of 
DADMAC:DAA.HCl) was prepared in this Comparative Example 11. 
269.5 parts of 60 wt % diallyldimethylammonium chloride in water were 
degassed with nitrogen for about 30 minutes. The degassed solution was 
warmed to 70.degree. C. while stirring. After warming, 2.56 parts of 
2,2'-azobis(2-amidinopropane) hydrochloride in 23 parts of distilled, 
degassed water were added at a constant rate over about 25.7 hours. 123.0, 
120.6 and 59.2 parts of distilled, degassed water were added after about 
1.5, 1.7 and 4.3, hours, respectively, after beginning the addition of the 
initiator. About one hour after the initiator addition was complete, the 
mixture was blanketed with air and allowed to cool to ambient temperature. 
SEC measurements determined that the product had a weight average 
molecular weight (M.sub.w) of about 385,000 with a polydispersity of 12.9. 
Carbon 13 NMR analysis indicated that 95% (mole basis) of the monomer had 
polymerized. 
EXAMPLE 12 
A water-soluble copolymer of diallyldimethylammonium ammonium chloride and 
diallylammonium chloride, having a monomer mole ratio of 7:3 
DADMAC:DAA.HCl, was prepared as follows: 
94.3 parts of 60 wt % diallyldimethylammonium chloride in water and 40.4 
parts of 49.6 wt % diallylammonium chloride in water were degassed with 
nitrogen for about 30 minutes while the solution was brought up to 
40.degree. C. The degassed solution was warmed to 70.degree. C. while 
stirring. After warming, 2.56 parts of 2,2'-azobis(2-amidinopropane) 
hydrochloride in 20 parts of distilled, degassed water were added at a 
constant rate over about 21.7 hours. 50.0 and 30.0 part aliquots of 
distilled, degassed water were added after about 3.7 and 4.5 hours, 
respectively, after beginning the addition of the initiator. About 1 hour 
after the initiator addition was complete, the mixture was blanketed with 
air and 23.6 parts of water were added and allowed to cool to ambient 
temperature. SEC measurements determined that the product had a weight 
average molecular weight (M.sub.w) of about 387,000 with a polydispersity 
of 12.2. Carbon 13 NMR analysis indicated that 98% (mole basis) of the 
monomers had polymerized. 
EXAMPLE 13 
A water-soluble copolymer of diallyldimethylammonium ammonium chloride and 
diallylammonium chloride, having a monomer mole ratio of 3:7 
DADMAC:DAA.HCl, was prepared as follows: 
40.5 parts of 60 wt % diallyldimethylammonium chloride in water and 94.2 
parts of 49.6 wt % diallylammonium chloride in water were degassed with 
nitrogen for about 30 minutes while the solution was brought up to 
40.degree. C. The degassed solution was warmed to 70.degree. C. while 
stirring. After warming, 2.56 parts of 2,2'-azobis(2-amidinopropane) 
hydrochloride in 20 parts of distilled, degassed water was added at a 
constant rate over about 27.5 hours. 30.0, 50.0 and 20.0 part aliquots of 
distilled, degassed water were added after about 7, 8 and 11 hours, 
respectively, after beginning the addition of the initiator. About 0.5 
hour after the initiator addition was complete, the mixture was blanketed 
with air and allowed to cool to ambient temperature. SEC measurements 
determined that the product had a weight average molecular weight 
(M.sub.w) of about 347,000 with a polydispersity of 12.5. Carbon 13 NMR 
analysis indicated that 96% (mole basis) of the monomers had polymerized. 
Comparative Example 14 
A homopolymer of diallylammonium chloride (0:100 mole ratio of 
DADMAC:DAA.HCl) was prepared in this Comparative Example 14. 
268.1 parts of 49.8 wt % diallylammonium chloride in water were degassed 
with nitrogen for about 30 minutes. The degassed solution was warmed to 
70.degree. C. while stirring. After warming, 3.84 parts of 
2,2'-azobis(2-amidinopropane) hydrochloride in 33 parts of distilled, 
degassed water were added at a constant rate over about 24 hours. 50.0 and 
50.0 parts of distilled, degassed water were added after about 21.5 and 24 
hours, respectively, after beginning the addition of the initiator. About 
16 hours after the initiator addition was complete, the mixture was 
blanketed with air and allowed to cool to ambient temperature. SEC 
measurements determined that the product had a weight average molecular 
weight (M.sub.w) of about 385,000 with a polydispersity of 13. Carbon 13 
NMR analysis indicated that 86% (mole basis) of the monomer had 
polymerized. 
EXAMPLE 15 
A water-soluble copolymer of diallyldimethylammonium ammonium chloride and 
diallylammonium chloride, having a monomer mole ratio of 5:5 
DADMAC:DAA.HCl, was prepared as follows: 
134.7 parts of 60 wt % diallyldimethylammonium chloride in water and 134.3 
parts of 49.7 wt % diallylammonium chloride in water were degassed with 
nitrogen for about 30 minutes while the solution was brought up to 
40.degree. C. The degassed solution was warmed to 70.degree. C. while 
stirring. After warming, 2.56 parts of 2,2'-azobis(2-amidinopropane) 
hydrochloride in 22 parts of distilled, degassed water was added at a 
constant rate over about 25 hours. 19.4, 30.0, 29.7, 46.9, 30.4, 19.3 and 
31.3 part aliquots of distilled, degassed water were added after about 11, 
11.5, 12, 12.5, 13.5, 14 and 15.5 hours, respectively, after beginning the 
addition of the initiator. The solution was allowed to cool to ambient 
temperature and 400 parts of water were added. SEC measurements determined 
that the product had a weight average molecular weight (M.sub.w) of about 
399,000 with a polydispersity of 8.1 Carbon 13 NMR analysis indicated that 
79% (mole basis) of the monomers had polymerized. 
EXAMPLE 16 
A water-soluble copolymer of diallyldimethylammonium ammonium chloride and 
diallylammonium chloride, having a monomer mole ratio of 5:5 
DADMAC:DAA.HCl, was prepared as follows: 
67.3 parts of 60 wt % diallyldimethylammonium chloride in water and 66.8 
parts of 50.0 wt % diallylammonium chloride in water and 7 parts of 
distilled water were warmed to 55.degree. C. while stirring. After 
warming, the solution was degassed with nitrogen for about 30 minutes. 
0.68 parts of 2,2'-azobis (2-amidinopropane) hydrochloride in 5 part of 
distilled, degassed water were then added over 1 minute. 35 and 66 part 
aliquots of distilled, degassed water were added after about 1 and 2 
hours. The mixture was stirred for an additional 3 hours, cooled to about 
30.degree. C., and sparged with air for 30 minutes. SEC measurements 
determined that the product had a weight average molecular weight 
(M.sub.w) of about 277,000 with a polydispersity of 3.6. Carbon 13 NMR 
analysis indicated that 50% (mole basis) of the monomers had polymerized. 
EXAMPLE 17 
A water-soluble copolymer of diallyldimethylammonium ammonium chloride and 
diallylammonium chloride, having a monomer mole ratio of 3:7 
DADMAC:DAA.HCl, was prepared as follows: 
40.5 parts of 60 wt % diallyldimethylammonium chloride in water and 93.5 
parts of 50.0 wt % diallylammonium chloride in water and 2 parts of 
distilled water were warmed to 55.degree. C. while stirring. After 
warming, the solution was degassed with nitrogen for about 30 minutes. 
0.68 parts of 2,2'-azobis (2-amidinopropane) hydrochloride in 5 parts of 
distilled, degassed water were then added over 1 minute. 38 parts of 
distilled, degassed water were added after about 0.75 hour. The mixture 
was stirred for an additional 3 hours, cooled to about 30.degree. C., and 
sparged with air for 30 minutes. SEC measurements determined that the 
product had a weight average molecular weight (M.sub.w) of about 392,000 
with a polydispersity of 5.8. Carbon 13 NMR analysis indicated that 50% 
(mole basis) of the monomers had polymerized. 
EXAMPLE 18 
A water-soluble copolymer of diallyldimethylammonium ammonium chloride and 
diallylammonium chloride, having a monomer mole ratio of 1:9 
DADMAC:DAA.HCl, was prepared as follows: 
13.5 parts of 60 wt % diallyldimethylammonium chloride in water and 120.2 
parts of 50.0 wt % diallylammonium chloride in water and 3 parts of 
distilled water were warmed to 55.degree. C. while stirring. After 
warming, the solution was degassed with nitrogen for about 30 minutes. 
0.68 parts of 2,2'-azobis (2-amidinopropane) hydrochloride in 5 parts of 
distilled, degassed water were then added over 1 minute. The mixture was 
stirred for an additional 4.5 hours, cooled to about 30.degree. C., and 
sparged with air for 30 minutes. SEC measurements determined that the 
product had a weight average molecular weight (M.sub.w) of about 332,000 
with a polydispersity of 5.4. Carbon 13 NMR analysis indicated that 40% 
(mole basis) of the monomers had polymerized. 
Examples 19-22 illustrate the preparation of polymerization reaction 
products having a wide range of weight average molecular weights, but with 
the monomer mole ratio being constant. 
EXAMPLE 19 
A water-soluble copolymer of diallyldimethylammonium ammonium chloride and 
diallylammonium chloride, having a monomer mole ratio of 3:7 
DADMAC:DAA.HCl, was prepared as follows: 
20 parts of distilled, degassed water was heated to 70.degree. C. 40.5 
parts of 60 wt % diallyldimethylammonium chloride in water, 94.2 parts of 
49.6 wt % diallylammonium chloride in water and 2.56 parts of 2,2'-azobis 
(2-amidinopropane) hydrochloride in 20 parts of water were degassed with 
nitrogen for about 30 minutes. The mixture was added to the 70.degree. C. 
water over a period of about 60 hours. About 4 hours after the initiator 
addition was complete, the solution was allowed to cool to ambient 
temperature. SEC measurements determined that the product had a weight 
average molecular weight (M.sub.w) of about 58,000 with a polydispersity 
of 2.8. Carbon 13 NMR analysis indicated that 75% (mole basis) of the 
monomers had polymerized. 
EXAMPLE 20 
Another water-soluble copolymer of diallyldimethylammonium chloride and 
diallylammonium chloride, having a monomer mole ratio of 3:7 
DADMAC:DAA.HCl, was prepared as follows: 
40.5 parts of 60 wt % diallyldimethylammonium chloride in water and 94.2 
parts of 49.6 wt % diallylammonium chloride in water were degassed with 
nitrogen for about 30 minutes while the solution was brought up to 
40.degree. C. The degassed solution was warmed to 70.degree. C. while 
stirring. After warming, 2.56 parts of 2,2'-azobis (2-amidinopropane) 
hydrochloride in 20 parts of distilled, degassed water was added over 27 
minutes. After about 46 hours after the initiator addition was complete, 
the solution was allowed to cool to ambient temperature. SEC measurements 
determined that the product had a weight average molecular weight M.sub.w) 
of about 88,000 with a polydispersity of 3.7. Carbon 13 NMR analysis 
indicated that 82% (mole basis) of the monomers had polymerized. 
EXAMPLE 21 
Another water-soluble copolymer of diallyldimethylammonium chloride and 
diallylammonium chloride, having a monomer mole ratio of 3:7 
DADMAC:DAA.HCl, was prepared as follows: 
40.5 parts of 60 wt % diallyldimethylammonium chloride in water and 94.0 
parts of 49.7 wt % diallylammonium chloride in water were degassed with 
nitrogen for about 30 minutes while the solution was brought up to 
40.degree. C. The degassed solution was warmed to 70.degree. C. while 
stirring. After warming, 0.64 parts of 2,2'-azobis (2-amidinopropane) 
hydrochloride in 5 parts of distilled, degassed water was added at a 
constant rate over about 28.5 hours. About one hour after the initiator 
addition was complete, the solution was allowed to cool to ambient 
temperature. SEC measurements determined that the product had a weight 
average molecular weight M.sub.w) of about 133,000 with a polydispersity 
of 3.3. Carbon 13 NMR analysis indicated that 38% (mole basis) of the 
monomers had polymerized. 
EXAMPLE 22 
Another water-soluble copolymer of diallyldimethylammonium chloride and 
diallylammonium chloride, having a monomer mole ratio of 3:7 
DADMAC:DAA.HCl, was prepared as follows 
40.5 parts of 60 wt % diallyldimethylammonium chloride in water and 94.0 
parts of 49.7 wt % diallylammonium chloride in water and 5 parts of 
distilled water were degassed with nitrogen for about 30 minutes while the 
solution was brought up to 55.degree. C. 0.32 parts of 2,2'-azobis 
(2-amidinopropane) hydrochloride in 2.5 parts of distilled, degassed water 
was added over about 3 minutes. After about 3 hours, 0.16 parts of 
additional 2,2'-azobis(2-amidinopropane hydrochloride in 1.75 parts of 
distilled, degassed water was added over 2 minutes. After 5 hours, the 
solution was sparged with air and allowed to cool to ambient temperature. 
SEC measurements determined that the product had a weight average 
molecular weight (M.sub.w) of about 283,000 with a polydispersity of 4.3. 
Carbon 13 NMR analysis indicated that 16% (mole basis) of the monomers 
polymerized. 
EXAMPLE 23 
A water-soluble copolymer of diallyldimethylammonium ammonium chloride and 
diallylammonium chloride, having a mole ratio of 8:2 DADMAC:DAA.HCl, was 
prepared using a combination of initiators in the polymerization reaction, 
as follows: 
199.38 parts of 65 wt % diallyldimethylammonium chloride in water and 39.12 
parts of 68 wt % diallylammonium chloride in water are degassed with 
nitrogen for 60 minutes and warmed to 70.degree. C. while stirring. 1.25 
parts of 2,2'-azobis (2-amidinopropane) hydrochloride in 12.5 parts of 
distilled, degassed water is added at a constant rate over 3 hours. After 
addition of this initiator was complete, 37.5 parts of 10% ammonium 
persulfate solution was thoroughly mixed into the reaction solution. 
Stirring was stopped and the mixture was heated to 95.degree. C. and held 
for 3 hours. The mixture was then diluted with water to 20% solids and 
allowed to cool to about 25.degree. C. SEC measurements determined that 
the product had a weight average molecular weight M.sub.w) of 448,000 and 
a polydispersity of 11.2 Carbon 13 NMR analysis indicated that 87% (mole 
basis) of the monomers had polymerized. 
The Examples which follow demonstrate the performance characteristics of 
the polymerization reaction products of this invention in enhancing paper 
sizing properties. 
Paper Making General Procedures 
Preparation of the paper in Examples 24-38, described below, utilized the 
following general procedures. 
Examples 24-31 and 35-38, described below, are based on internal addition 
of the paper sizing agent and sizing enhancers (as opposed to a surface 
application method). In those Examples, a pilot scale Fourdrinier 
papermaking machine was operated to make 65 g/m.sup.2 basis weight paper. 
Chemical additives, including paper sizing agents and sizing enhancers, 
were added to the paper furnish (pulp and filler) during operation of the 
papermaking machine. The type of furnish, chemical additives employed and 
points at which the additives were introduced are noted. Addition levels 
of chemical additives are expressed as a percentage of the dry weight of 
the paper furnish. 
Examples 32-34, described below, utilized a surface application method in 
which standard 65 g/m.sup.2 basis weight kraft paper was surface treated 
(as described in the Examples) with chemical additives, including sizing 
agents and sizing enhancers. The paper used in Examples 32-34, described 
below, was prepared using a pilot Fourdrinier papermaking machine using a 
70:30 bleached hardwood:bleached softwood pulp beaten to 425 mL Canadian 
standard freeness (TAPPI Standard T227). The paper contained 12 wt % 
precipitated calcium carbonate filler. 
EXAMPLE 24 
The performance of the polymerization reaction product prepared in Example 
1 was evaluated in sized paper at several different use levels, with two 
different commercial sizing agents. Commercially available sizing 
enhancers were also included in the evaluation to provide a performance 
benchmark for the polymerization reaction product sizing enhancer of this 
invention. A control, with no sizing enhancer present, was also included 
in the evaluation. 
The commercial sizing agents utilized were Precis.RTM. 2000 paper sizing 
agent (Hercules Incorporated, Wilmington, Del.), an aqueous 
starch-stabilized reactive alkaline sizing dispersion, and Hercon.RTM. 70 
paper sizing agent (Hercules Incorporated, Wilmington, Del.), an aqueous 
alkyl ketene dimer sizing dispersion. The Precis.RTM. 2000 sizing agent 
was evaluated at a concentration of 0.09 wt %, and the Hercon.RTM. 70 
sizing agent was evaluated at two different concentrations, 0.06 wt % and 
0.07 wt %. All sizing agent concentrations noted in this Example and in 
subsequent Examples are based on the dry weight of the paper furnish. 
Three commercial, state-of-the-art sizing enhancers were utilized for 
comparison purposes: 
Reten.RTM. 203 resin (Hercules Incorporated, Wilmington, Del.)--a 
homopolymer of diallyldimethylammonium chloride; 
Reten.RTM. 204 resin (Hercules Incorporated, Wilmington, 
Del.)--polyamine/epichlorohydrin polymer; and 
Reten.RTM. 201 (Hercules Incorporated, Wilmington, Del.)--a low molecular 
weight, high charge density polyamine/epichlorohydrin polymer. 
Three different concentrations of sizing enhancer were evaluated for each 
sizing agent parameter set employed, as shown in Table 1 below. All sizing 
enhancer concentrations noted in Table 1 of this Example and in subsequent 
Examples are based on the dry weight of the paper furnish. 
The pilot Fourdrinier papermaking machine was operated with a paper furnish 
of 70:30 bleached hardwood:bleached softwood beaten to 417 mL Canadian 
standard freeness. Paper furnish was warmed to about 44.degree. C. with 
steam at the constant level chest for all internal additions unless 
otherwise indicated. Additives employed included 20 wt % precipitated 
calcium carbonate filler added at the machine chest, 0.1 wt % alum added 
at the fan pump inlet, 0.02 wt % retention aid (high weight average 
molecular weight (10.sup.7) acrylate:acrylamide (3:7) polymer) added at 
the fan pump outlet, 0.4 wt % cationic starch added at the first mix box, 
paper sizing agent added at the second mix box and sizing enhancer also 
added at the second mix box. System pH was maintained at 8.2. 
Table 1 below summarizes the results, measured as Hercules Size Test (HST) 
measurements (with aqueous 1% formic acid and naphthol green dye, for an 
80% reflectance endpoint), for all of the evaluations carried out in this 
Example. The results demonstrate the clear and consistently superior 
sizing property obtained with the polymerization reaction product of this 
invention, at all concentration levels of sizing agents and enhancers 
employed. 
TABLE 1 
______________________________________ 
Amount of 
Sizing Agent Sizing Enhancer 
HST Sizing 
and Amount Added 
Sizing Added Property 
(wt %) Enhancer (wt %) (sec) 
______________________________________ 
Precis .RTM. 2000 
None 0 7 
0.09 
Precis .RTM. 2000 
Reten .RTM. 203 
0.0225 26 
0.09 
Precis .RTM. 2000 
Reten .RTM. 204 
0.0225 38 
0.09 
Precis .RTM. 2000 
Example 1 0.0225 42 
0.09 Copolymer 
Precis .RTM. 2000 
Reten .RTM. 203 
0.045 66 
0.09 
Precis .RTM. 2000 
Reten .RTM. 204 
0.045 59 
0.09 
Precis .RTM. 2000 
Example 1 0.045 116 
0.09 Copolymer 
Precis .RTM. 2000 
Reten .RTM. 203 
0.09 140 
0.09 
Precis .RTM. 2000 
Reten .RTM. 204 
0.09 89 
0.09 
Precis .RTM. 2000 
Example 1 0.09 209 
0.09 Copolymer 
Hercon .RTM. 70 
None 0 1 
0.06 
Hercon .RTM. 70 
Reten .RTM. 201 
0.015 4 
0.06 
Hercon .RTM. 70 
Example 1 0.015 6 
0.06 Copolymer 
Hercon .RTM. 70 
Reten .RTM. 201 
0.03 4 
0.06 
Hercon .RTM. 70 
Example 1 0.03 53 
0.06 Copolymer 
Hercon .RTM. 70 
Reten .RTM. 201 
0.06 4 
0.06 
Hercon .RTM. 70 
Example 1 0.06 206 
0.06 Copolymer 
Hercon .RTM. 70 
None 0 3 
0.07 
Hercon .RTM. 70 
Reten .RTM. 201 
0.0175 15 
0.07 
Hercon .RTM. 70 
Example 1 0.0175 61 
0.07 Copolymer 
Hercon .RTM. 70 
Reten .RTM. 201 
0.035 24 
0.07 
Hercon .RTM. 70 
Example 1 0.035 133 
0.07 Copolymer 
Hercon .RTM. 70 
Reten .RTM. 201 
0.07 13 
0.07 
Hercon .RTM. 70 
Example 1 0.07 284 
0.07 Copolymer 
______________________________________ 
EXAMPLE 25 
In this Example, the performance of the polymerization reaction product 
prepared in Example 1 was evaluated further in sized paper at several 
different use levels, with a commercial sizing agent. The procedure of 
this Example 25 used papermaking conditions different from those described 
for Example 24. Commercially available sizing enhancers were again 
included in the evaluation to provide a performance benchmark for the 
polymerization reaction product sizing enhancer of this invention. A 
control, with no sizing enhancer present, was also included in the 
evaluation. 
The commercial sizing agent utilized was Hercon.RTM. 70 paper sizing agent, 
and it was evaluated at two different concentrations, 0.1 wt % and 0.15 wt 
%. 
The two commercial sizing enhancers utilized in this Example were 
Reten.RTM. 203 resin; and Reten.RTM. 204 resin. 
Three different concentrations of sizing enhancer were evaluated, two at 
one sizing agent concentration and the third, at a higher sizing agent use 
level, all as shown in Table 2 below. 
The pilot Fourdrinier papermaking machine was operated with a paper furnish 
of 50:25:15:10 coated broke:bleached hardwood kraft:bleached softwood 
kraft:chemithermomechanical pulp. Additives employed included 6 wt % 
precipitated calcium carbonate filler and 4 wt % titanium oxide filler 
added at the blend chest, 0.2 wt % Reten.RTM. 201 sizing enhancer 
(Hercules Incorporated, Wilmington, Del.) added at the fan pump inlet, 
0.02 wt % retention aid (high weight average molecular weight 
(2.times.10.sup.7) acrylate:acrylamide (3:7) polymer) added at the fan 
pump outlet, 0.7 wt % cationic starch added at the first mix box, paper 
sizing agent added at the first mix box and sizing enhancer added at the 
second mix box. System pH was maintained at 8.2. 
Table 2 below summarizes the results, measured as Hercules Size Test 
measurements taken immediately after the sized paper was made and also 
taken seven days later for the aged sized paper, for the evaluations 
carried out in this Example. The results demonstrate the increased sizing 
efficiency and increased rate of sizing property obtained with the 
polymerization reaction product of this invention, at all concentration 
levels of sizing agent and enhancers employed. 
TABLE 2 
______________________________________ 
HST Sizing 
Amount of 
Property: 
HST Sizing 
Sizing Agent Sizing directly 
Property: 
and Amount Enhancer after paper 
after paper 
Added Sizing Added was made 
aged 7 days 
(wt %) Enhancer (wt %) (sec) (sec) 
______________________________________ 
Hercon .RTM. 70 
None 0 4 59 
0.1 
Hercon .RTM. 70 
Reten .RTM. 204 
0.033 3 78 
0.1 
Hercon .RTM. 70 
Reten .RTM. 203 
0.033 9 81 
0.1 
Hercon .RTM. 70 
Example 1 0.033 11 106 
0.1 Copolymer 
Hercon .RTM. 70 
Reten .RTM. 204 
0.067 6 105 
0.1 
Hercon .RTM. 70 
Reten .RTM. 203 
0.067 12 97 
0.1 
Hercon .RTM. 70 
Example 1 0.067 49 115 
0.1 Copolymer 
Hercon .RTM. 70 
None 0 21 181 
0.15 
Hercon .RTM. 70 
Reten .RTM. 204 
0.1 36 234 
0.15 
Hercon .RTM. 70 
Reten .RTM. 203 
0.1 58 215 
0.15 
Hercon .RTM. 70 
Example 1 0.1 139 294 
0.15 Copolymer 
______________________________________ 
EXAMPLE 26 
In this Example, the performance of the polymerization reaction product 
prepared in Example 1 was again evaluated as a sizing enhancer in sized 
paper, using Precis.RTM. 2000 paper sizing agent. For comparison, four 
different levels of sizing agent were used without any sizing enhancer 
present, as a control to gauge the performance effectiveness of the 
polymerization reaction product of this invention at a single use level. 
The papermaking system described for Example 24 was again used, except that 
50% of the paper furnish was recycled newsblank. 
Table 3 below summarizes the results, measured as Hercules Size Test 
measurements taken immediately after the sized paper was made and also 28 
days later for the aged sized paper. The results demonstrate that the 
polymerization reaction product enhancer of this invention accelerates the 
rate at which the sizing property develops and also increases the sizing 
efficiency. 
TABLE 3 
______________________________________ 
HST HST Percentage 
Sizing Sizing of Sizing 
Property: 
Property: 
Property 
Sizing Amount of 
directly 
after developed 
Agent Sizing after paper directly 
and Amount 
Sizing Enhancer paper was 
aged after 
Added En- Added made 4 weeks 
paper 
(wt %) hancer (wt %) (sec) (sec) was made 
______________________________________ 
Precis .RTM. 2000 
None 0 5 8 63 
0.20 
Precis .RTM. 2000 
None 0 7 28 25 
0.25 
Precis .RTM. 2000 
None 0 7 73 10 
0.30 
Precis .RTM. 2000 
None 0 6 333 2 
0.40 
Precis .RTM. 2000 
Ex- 0.05 36 39 92 
0.20 ample 1 
Co- 
polymer 
Precis .RTM. 2000 
Ex- 0.1 157 148 100 
0.20 ample 1 
Co- 
polymer 
Precis .RTM. 2000 
Ex- 0.2 239 199 100 
0.20 ample 1 
Co- 
polymer 
______________________________________ 
EXAMPLE 27 
In this Example, two different versions of the polymerization reaction 
product were compared for their performance as sizing enhancers in sized 
paper. 
For comparison, sized paper containing no enhancer (at two use levels of 
sizing agent) and sized paper containing two different commercial sizing 
enhancers were also included in the evaluation. 
The paper was sized in each of these studies with Hercon.RTM. 70 sizing 
agent. The papermaking procedure was identical to that described in 
Example 24, except that 15 wt % clay filler was employed (in place of the 
precipitated calcium carbonate filler) and 0.5 wt % cationic starch was 
added (instead of 0.4 wt %). System pH was maintained at 7.1, since the 
precipitated calcium carbonate filler that was used previously was 
replaced with the clay filler. 
The polymerization reaction products utilized in this Example were prepared 
from a 9:1 mole ratio of DADMAC:DAA.HCl in one case, and an 7:3 mole ratio 
of DADMAC:DAA.HCl in the second case, as described in Examples 4 and 5, 
respectively. 
The two commercial sizing enhancers used for comparative purposes were 
Reten.RTM. 203 resin and Reten.RTM. 204 resin. 
Table 4 below summarizes the results, measured as Hercules Size Test 
measurements taken immediately after the sized paper was made and also 
seven days later for the aged sized paper. The results demonstrate that 
use of the polymerization reaction products of this invention as sizing 
enhancers provided a higher percentage of ultimate sizing property in the 
sized paper immediately after its manufacture, as compared with the sizing 
property achieved after seven days. The data in Table 4 indicate that use 
of the sizing enhancers of this invention accelerates the rate at which 
the sizing property develops. 
TABLE 4 
__________________________________________________________________________ 
Percentage 
HST Sizing of Sizing 
Amount of 
Property: 
HST Sizing 
Property 
Sizing Agent Sizing 
directly 
Property: 
developed 
and Amount Enhancer 
after paper 
after paper 
directly 
Added Sizing Added is made 
aged 7 days 
after paper 
(wt %) Enhancer (wt %) 
(sec) (sec) was made 
__________________________________________________________________________ 
Hercon .RTM. 70 
None 0 0 2 0 
0.10 
Hercon .RTM. 70 
None 0 4 1063 0.4 
0.20 
Hercon .RTM. 70 
Reten .RTM. 204 
0.15 1 1047 1 
0.10 
Hercon .RTM. 70 
Reten .RTM. 203 
0.15 34 389 9 
0.10 
Hercon .RTM. 70 
Example 4 0.12 121 722 17 
0.10 Copolymer 
9:1 
DADMAC:DAA.HCl 
Hercon .RTM. 70 
Example 5 0.12 273 1002 27 
0.10 Copolymer 
7:3 
DADMAC:DAA.HCl 
__________________________________________________________________________ 
EXAMPLE 28 
In this Example, the performance of the polymerization reaction product 
prepared in Example 1 was demonstrated further in a papermaking system 
different from those utilized in Examples 25-27 but similar to that 
utilized in Example 24. 
The polymerization reaction product of Example 1 was utilized as a sizing 
enhancer at three different concentrations, as shown in Table 5 below, for 
two different use levels of Precis.RTM. 2000 paper sizing agent, the 
commercial sizing agent that was employed in this Example. Controls, in 
which no sizing enhancer was used, were also included at the two use 
levels of commercial sizing agent that were used. 
The pilot Fourdrinier papermaking machine was operated with a paper furnish 
of 70:30 bleached hardwood:bleached softwood beaten to 417 mL Canadian 
standard freeness. Additives employed included 5 wt % precipitated calcium 
carbonate filler added at the third mix box, 0.1 wt % alum added at the 
fan pump inlet, 0.02 wt % retention aid (high weight average molecular 
weight (10.sup.7) acrylate:acrylamide (3:7) polymer) added at the fan pump 
outlet, Precis.RTM. 2000 paper sizing agent added at the second mix box 
and sizing enhancer also added at the second mix box. 
Table 5 below summarizes the results, measured as Hercules Size Test 
measurements taken immediately after the sized paper was made and also 28 
days later for the aged sized paper. The results demonstrate that use of 
the polymerization reaction product of this invention as a sizing enhancer 
provides good sizing property efficiency at relatively low sizing agent 
concentrations and also accelerates the rate at which the sizing property 
develops. 
TABLE 5 
______________________________________ 
HST Sizing 
Property: 
HST Sizing 
Sizing Agent Amount of 
directly 
Property: 
and Amount Sizing after paper 
after paper 
Added Sizing Enhancer was made 
aged 28 days 
(wt %) Enhancer Added (sec) (sec) 
______________________________________ 
Precis .RTM. 2000 
None 0 2 59 
0.09 
Precis .RTM. 2000 
Example 1 0.0225 55 147 
0.09 Copolymer 
Precis .RTM. 2000 
Example 1 0.045 163 214 
0.09 Copolymer 
Precis .RTM. 2000 
Example 1 0.09 306 309 
0.09 Copolymer 
Precis .RTM. 2000 
None 0 0 1 
0.06 
Precis .RTM. 2000 
Example 1 0.0225 2 14 
0.06 Copolymer 
Precis .RTM. 2000 
Example 1 0.045 49 72 
0.06 Copolymer 
Precis .RTM. 2000 
Example 1 0.09 152 196 
0.06 Copolymer 
______________________________________ 
EXAMPLE 29 
In this Example, the performance of the polymerization reaction product 
prepared in Example 1 was evaluated as a sizing enhancer with three 
different commercial sizing agents, the use levels of sizing enhancer and 
of each sizing agent being identical in each evaluation. A control, with 
no sizing enhancer being present, was also included in the evaluation of 
each of the three sizing agents. 
The papermaking system was identical to that described for Example 28. 
The three sizing agents employed, each at a use level of 0.06 wt %, were 
Precis.RTM. 2000 sizing agent, alkenyl succinic acid anhydride (ASA), and 
Hercon.RTM. 70 sizing agent. The polymerization reaction product of 
Example 10 was used as a sizing enhancer at a concentration of 0.06 wt %. 
Table 6 below summarizes the results, measured as Hercules Size Test 
measurements taken immediately after the sized paper was made. The results 
demonstrate a substantial increase in the sizing property benefit was 
obtained by use of the sizing enhancer of this invention, for each of the 
three sizing agents evaluated. 
TABLE 6 
______________________________________ 
Amount of HST 
Sizing Agent Sizing Enhancer 
Sizing 
and Amount Added 
Sizing Added Property 
(wt %) Enhancer (wt %) (sec) 
______________________________________ 
Precis .RTM. 2000 
None 0 2 
0.06 
Precis .RTM. 2000 
Example 10 0.06 98 
0.06 Copolymer 
0.06 ASA None 0 6 
0.06 ASA Example 10 0.06 17 
Copolymer 
Hercon .RTM. 70 
None 0 2 
0.06 
Hercon .RTM. 70 
Example 10 0.06 116 
0.06 Copolymer 
______________________________________ 
EXAMPLE 30 
In this Example, three different versions of the polymerization reaction 
product were evaluated as sizing enhancers, the reaction products 
containing monomer mole ratios that ranged from 8:2 to 9:1 DADMAC:DAA.HCl. 
Note that in Example 27, the two monomeric mole ratios were 9:1 and 7:3 
for the polymerization reaction products of that Example. These three 
products were evaluated as sizing enhancers at three different 
concentrations (for each of the three products) in paper sized with 0.075 
wt % Precis.RTM. 2000 sizing agent. A control, with no sizing enhancer 
present, was also included in the evaluation. 
The polymerization reaction products utilized in this Example were prepared 
respectively from 90:10, 85:15 and 80:20 mole ratios of DADMAC:DAA.HCl. 
The polymerization reaction products were prepared as described in 
Examples 8 (90:10 mole ratio), 7 (85:15 mole ratio) and 6 (80:20 mole 
ratio). These reaction products were used as sizing enhancers at three 
concentrations, 0.019 wt %, 0.038 wt % and 0.075 wt %. 
The papermaking procedure was identical to that described for Example 24. 
Table 7 below summarizes the results, measured as Hercules Size Test 
measurements taken immediately after the sized paper was made. The results 
demonstrate that the polymerization reaction products with monomeric molar 
ratios of 8:2 to 9:1 provide approximately equivalent sizing property 
enhancement within the range of ratios studied, for the conditions 
employed in this evaluation. 
TABLE 7 
______________________________________ 
Copolymer Sizing 
Amount of HST 
Sizing Agent and 
Enhancer Sizing Sizing 
Amount Added 
DADMAC:DAA.HCl 
Enhancer Property 
(wt %) Mole Ratio Added (wt %) 
(sec) 
______________________________________ 
Precis .RTM. 2000 
NA 0 10 
0.075 
Precis .RTM. 2000 
9:1 0.019 34 
0.075 
Precis .RTM. 2000 
8.5:1.5 0.019 30 
0.075 
Precis .RTM. 2000 
8:2 0.019 38 
0.075 
Precis .RTM. 2000 
9:1 0.038 65 
0.075 
Precis .RTM. 2000 
8.5:1.5 0.038 74 
0.075 
Precis .RTM. 2000 
8:2 0.038 82 
0.075 
Precis .RTM. 2000 
9:1 0.075 179 
0.075 
Precis .RTM. 2000 
8.5:1.5 0.075 122 
0.075 
Precis .RTM. 2000 
8:2 0.075 205 
0.075 
______________________________________ 
EXAMPLE 31 
This Example utilized polymerization reaction products made with two 
different monomeric mole ratios, 6:4 and 8:2 DADMAC:DAA.HCl. 
The polymerization reaction products were prepared as described in Examples 
9 (6:4 mole ratio) and 1 (8:2 mole ratio). These reaction products were 
used as sizing enhancers at two concentrations, 0.055 wt % and 0.085 wt %. 
The sizing agent in this Example, as in Example 10 30, was Precis.RTM. 
2000, and two different use levels were employed, 0.11 wt % and 0.2 wt %. 
Controls with sizing agent at higher use levels 0.16 wt % and 0.3 wt %, 
but without sizing enhancers being present, were also included in the 
evaluation. 
The papermaking procedures and paper furnish differed from that of Example 
30 and were as follows. 
The pilot Fourdrinier papermaking machine was operated with a paper furnish 
of 45:55 recycled plate stock:recycled post-consumer fine paper. Additives 
employed included 20 wt % precipitated calcium carbonate filler added at 
the third mix box, 0.01 wt % (high weight average molecular weight 
(10.sup.7) acrylate:acrylamide (3:7) polymer) retention aid added at the 
fan pump outlet, 0.7 wt % cationic starch added at the first mix box, 
Precis.RTM. 2000 paper sizing agent also added at the first mix box and 
sizing enhancer added at the second mix box. 
Table 8 below summarizes the results, measured as Hercules Size Test 
measurements taken immediately after the sized paper was made, as well as 
seven days later for the aged sized paper. The results demonstrate that 
the 8:2 monomer molar ratio in the polymerization reaction product 
provides somewhat faster acceleration of the sizing property, as evidenced 
by the sizing property levels for the two ratios (8:2 and 6:4) at the time 
the sized paper was made. Overall sizing property achieved by use of the 
sizing enhancers of this invention in the aged paper appeared equivalent 
for the two monomer molar ratios studied. 
TABLE 8 
______________________________________ 
Copolymer HST Sizing 
Sizing Amount of 
Property: 
HST Sizing 
Sizing Agent 
Enhancer Sizing directly 
Property: 
and DADMAC: Enhancer after paper 
after paper 
Amount Added 
DAA.HC1 Added was made 
aged 7 days 
(wt %) Mole Ratio 
(wt %) (sec) (sec) 
______________________________________ 
Precis .RTM. 2000 
NA 0 1 6 
0.165 
Precis .RTM. 2000 
6:4 0.055 13 15 
0.11 
Precis .RTM. 2000 
8:2 0.055 20 20 
0.11 
Precis .RTM. 2000 
NA 0 4 25 
0.3 
Precis .RTM. 2000 
6:4 0.085 145 123 
0.2 
Precis .RTM. 2000 
8:2 0.085 171 130 
0.2 
______________________________________ 
EXAMPLE 32 
This Example 32 and the two subsequent Examples differ from the previous 
Examples 24-31 in that the sizing agents and sizing enhancers were applied 
to the paper as a surface treatment, after the paper had been 
manufactured. A description of the preformed paper employed in these 
Examples is provided in the Paper Making General Procedures, located 
above. 
In this Example 32, the polymerization reaction products of this invention 
are demonstrated to be effective as sizing enhancers when applied to the 
surface of preformed paper. The Example includes evaluations of 
polymerization reaction products containing monomer mole ratios that 
ranged from 1:9 to 9:1 DADMAC:DAA.HCl. 
The polymerization reaction products were prepared as described in previous 
Examples. The following monomer molar ratios of DADMAC:DAA.HCl were used, 
and the preparation Example is noted in parentheses in the second column 
of Table 9 below: 9:1, 8:2, 7:3, 6:4, 5:5, 3:7 and 1:9. These reaction 
products were used as sizing enhancers at two concentrations on the sized 
preformed paper, 0.04 wt % and 0.05 wt %, as noted in Table 9 below. Two 
controls, homopolymerization reaction products with molar ratios of 100:0 
and 0:100 DADMAC:DAA.HCl (prepared as described in Comparative Examples 11 
and 14, respectively), were also included for comparative purposes at 0.04 
wt % sizing enhancer use level. 
The surface treatment of the preformed paper was carried out as follows. 
Paper strips were passed through a laboratory single-nip two-roll 
puddle-type size press, containing a dilute aqueous solution, emulsion or 
dispersion of the chemical additive, i.e., sizing agent or sizing 
enhancer. The paper was immediately dried between the felt and stainless 
steel of a rotating drum-type drier, at a temperature of 82.degree. C. for 
20 seconds. 
For paper surface-treated with sizing agent and sizing enhancer, the 
aqueous solution of sizing enhancer was applied first by this procedure 
and then the aqueous dispersion of sizing agent was applied to the dried 
enhancer-coated paper in a second application using the same procedure. 
The amount of chemical additive on the surface-treated paper was 
calculated based on the weight of aqueous medium picked up by the paper 
strip. 
The commercial sizing agent employed in this Example was Hercon.RTM. 70 
sizing agent and two different use levels were employed, 0.10 wt % and 
0.118 wt %. Controls with the sizing agent, but without sizing enhancers 
being present, were also included in the evaluation. 
Table 9 below summarizes the results, measured as Hercules Size Test 
measurements taken immediately after the surface-treated sized paper was 
dried and also seven days later for the aged sized paper. The results 
demonstrate that the polymerization reaction products are highly effective 
in enhancing the sizing property, when applied as a surface-treatment to 
preformed paper, at all monomer molar ratios studied. The data also show 
that the sizing property development is also accelerated when the sizing 
enhancers of this invention are employed as a surface treatment on 
preformed sized paper. 
TABLE 9 
__________________________________________________________________________ 
Percentage 
Copolymer HST Sizing 
HST Sizing 
of Sizing 
Sizing Amount of 
Property: 
Property: 
Property 
Enhancer Sizing 
directly 
after developed 
Sizing Agent 
DADMAC:DAA.HCl 
Enhancer 
after paper 
paper aged 
directly 
and Mole Ratio Added was dried 
7 days after paper 
Amount Added 
(Example) (wt %) 
(sec) (sec) was made 
__________________________________________________________________________ 
Hercon .RTM. 70 
NA 0 2 112 2 
0.10 
Hercon .RTM. 70 
100:0 0.04 46 52 88 
0.10 (11) 
Hercon .RTM. 70 
8:2 0.04 136 190 72 
0.10 (10) 
Hercon .RTM. 70 
7:3 0.04 145 167 87 
0.10 (12) 
Hercon .RTM. 70 
6:4 0.04 173 193 90 
0.10 (9) 
Hercon .RTM. 70 
5:5 0.04 146 179 82 
0.10 (15) 
Hercon .RTM. 70 
3:7 0.04 96 151 64 
0.10 (13) 
Hercon .RTM. 70 
0:100 0.04 45 51 88 
0.10 (14) 
Hercon .RTM. 70 
NA 0 10 124 6 
0.118 
Hercon .RTM. 70 
9:1 0.05 169 185 91 
0.118 (4) 
Hercon .RTM. 70 
7:3 0.05 227 227 100 
0.118 (5) 
Hercon .RTM. 70 
5:5 0.05 96 224 43 
0.118 (16) 
Hercon .RTM. 70 
3:7 0.05 66 219 30 
0.118 (17) 
Hercon .RTM. 70 
1:9 0.05 32 182 18 
0.118 (18) 
__________________________________________________________________________ 
EXAMPLE 33 
This Example 33 was similar to Example 32 in that the sizing enhancer was 
again evaluated in a surface treatment procedure. In this Example, the 
polymerization reaction product of this invention is demonstrated to be an 
effective sizing enhancer over a broad range of polymer molecular weights 
in the reaction product. 
The polymerization reaction products were prepared as described in Examples 
17 and 19-22, using a monomer molar ratio of 3:7 DADMAC:DAA.HCl. The 
polymer molecular weights in the five reaction products studied ranged 
from 58,000 to 392,000, as determined by size exclusion chromatography. In 
Table 10 below, the preparation Examples are noted in parentheses in the 
second column. The reaction products were used as sizing enhancers at a 
concentration of 0.04 wt % on the sized preformed paper. 
The surface application procedures were carried out as described in Example 
32. The commercial sizing agent was again Hercon.RTM. 70 sizing agent, and 
the use level was 0.10 wt % on the preformed paper. A control with sizing 
agent, but without any sizing enhancer, was also included in the 
evaluation. 
Table 10 below summarizes the results, measured as Hercules Size Test 
measurements taken immediately after the surface-treated sized paper was 
dried and also seven days later for the aged sized paper. The results 
demonstrate that the polymerization reaction products are highly effective 
in enhancing the sizing property and in accelerating development of the 
sizing property, over the range of polymer molecular weights evaluated. 
TABLE 10 
______________________________________ 
Weight Average 
Molecular 
Weight (Mw) HST 
of Copolymer Sizing 
Sizing Enhancer 
Amount of 
Property: 
HST Sizing 
Sizing Agent 
(DADMAC: Sizing directly 
Property: 
and Amount 
DAA.HCl Enhancer after paper 
after paper 
Added 3:7 Mole Ratio) 
Added was dried 
aged 7 days 
(wt %) (Example) (wt %) (sec) (sec) 
______________________________________ 
Hercon .RTM. 70 
NA 0 2 112 
0.10 
Hercon .RTM. 70 
58,000 0.04 81 133 
0.10 (19) 
Hercon .RTM. 70 
88,000 0.04 118 154 
0.10 (20) 
Hercon .RTM. 70 
133,000 0.04 142 169 
0.10 (21) 
Hercon .RTM. 70 
283,000 0.04 178 213 
0.10 (22) 
Hercon .RTM. 70 
392,000 0.04 154 191 
0.10 (17) 
______________________________________ 
EXAMPLE 34 
In this Example, the polymerization reaction product of this invention was 
demonstrated to improve the print quality of sized paper that was 
surface-treated with the reaction product. 
The surface application procedures were carried out as described for 
Example 32. For this Example, the paper also contained sufficient 
Hercon.RTM. 70 sizing agent added via an internal addition method during 
papermaking to provide the paper with 39 seconds of sizing property as 
measured by the Hercules Size Test. 
The paper was surface-treated with an aqueous dispersion containing lightly 
oxidized corn starch, Precis.RTM. 2000 sizing agent and sizing enhancer, 
at a temperature of 60.degree. C. The sizing enhancer was the 
polymerization reaction product of Example 9 (6:4 DADMAC:DAA.HCl mole 
ratio) and was applied to the preformed paper at a concentration of 0.1 wt 
%. The commercial sizing agent was applied at two different use levels, 
0.0125 wt % and 0.025 wt %. The cornstarch was applied at a level of 5.4 
wt %. 
Evaluation of the surface-treated coated paper was carried out using an 
inkjet printer, with print quality being determined by visual inspection 
of the resolution of the printed letters. Print samples were compared 
against 10 standards ranked from 1-10, with 1 being the highest quality. 
Results are summarized in Table 11 below and demonstrate that higher inkjet 
print quality is obtained with the use of the polymerization reaction 
product of this invention as a surface-application treatment on sized 
preformed paper. 
TABLE 11 
______________________________________ 
Amount of 
Sizing Agent and Sizing 
Amount Added 
Sizing Enhancer Ink Jet Print 
(wt %) Enhancer Added (wt %) 
Quality 
______________________________________ 
Precis .RTM. 2000 
None 0 7 
0.0125 
Precis .RTM. 2000 
Example 9 0.1 3 
0.0125 Copolymer 
Precis .RTM. 2000 
None 0 5 
0.025 
Precis .RTM. 2000 
Example 9 0.1 2 
0.025 Copolymer 
______________________________________ 
EXAMPLE 35 
In this Example, the performance of the polymerization reaction product 
prepared as described in Example 10 was demonstrated in a papermaking 
system with parameters different from those utilized in the previous 
Example. 
The polymerization reaction product was employed as a sizing enhancer at 
two different concentrations for two different use levels of Hercon.RTM. 
70 paper sizing agent. The use levels of sizing enhancer and commercial 
sizing agent, shown in Table 12 below, were 0.07 wt % and 0.105 wt % 
sizing enhancer at 0.07 wt % Hercon.RTM. 70 sizing agent and 0.06 wt % and 
0.09 wt % sizing enhancer at 0.06 wt % Hercon.RTM. 70 sizing agent. 
Controls, in which no sizing enhancer was used, were also included at the 
two use levels of commercial sizing agent that were used. 
The papermaking procedure and paper furnish were as follows. The pilot 
Fourdrinier papermaking machine was operated with a paper furnish of 100% 
recycled newsblank at pH 6.9. Additives employed included 0.1 wt % alum 
added at the fan pump inlet, 0.02 wt % retention aid (high molecular 
weight (10.sup.7) acrylate:acrylamide (3:7) polymer) added at the fan pump 
outlet, Precis.RTM. 2000 paper sizing agent added at the second mix box, 
and sizing enhancer also added at the second mix box. No cationic starch 
or fillers were used in this Example. 
Table 12 below summarizes the results, measured as Hercules Size Test 
measurements taken immediately after the sized paper was made and also 
seven days later for the aged sized paper. The results demonstrate that 
use of the polymerization reaction product of this invention as a sizing 
enhancer provides increased efficacy of sizing agent benefit at relatively 
low sizing agent concentrations and also accelerates the rate at which the 
sizing property develops. The data from this and previous Examples 
demonstrate that polymerization reaction product of this invention is an 
effective sizing enhancer under a variety of papermaking conditions. 
TABLE 12 
______________________________________ 
Amount 
of HST Sizing 
HST Sizing 
Sizing Agent Sizing Property: 
Property: 
and Amount Enhancer directly after 
after paper 
Added Sizing Added paper is made 
aged 7 days 
(wt %) Enhancer (wt %) (sec) (sec) 
______________________________________ 
Hercon .RTM. 70 
None 0 2 71 
0.07 
Hercon .RTM. 70 
Example 10 
0.07 5 123 
0.07 Copolymer 
Hercon .RTM. 70 
Example 10 
0.105 9 208 
0.07 Copolymer 
Hercon .RTM. 70 
None 0 3 13 
0.06 
Hercon .RTM. 70 
Example 10 
0.06 8 35 
0.06 Copolymer 
Hercon .RTM. 70 
Example 10 
0.09 22 65 
0.06 Copolymer 
______________________________________ 
EXAMPLE 36 
In this Example, the polymerization reaction product of this invention was 
demonstrated to be effective as a sizing enhancer, both when added 
separately from the sizing agent and when preblended with the sizing 
agent. 
The polymerization reaction product was prepared as described in Example 1 
and was utilized as a sizing enhancer at three different concentrations, 
0.023 wt %, 0.047 wt % and 0.095 wt %, for a single use level, 0.08 wt %, 
of Precis.RTM. 2000 sizing agent. A control, with no sizing enhancer 
present, was also included in the evaluation. 
The papermaking system was essentially the same as that described for 
Example 24. 
In the situation where the sizing enhancer was blended with sizing agent, 
the resulting aqueous dispersion remained stable to agglomeration after 
storage at a temperature of 30.degree. C. for four weeks. 
Table 13 below summarizes the results, measured as Hercules Size Test 
measurements taken immediately after the sized paper was made. The results 
show that there was no difference in sizing property obtained for the 
preblended sizing agent and sizing enhancer and for the separately 
introduced components. In both approaches, the sizing enhancer of this 
invention provided an improvement in sizing agent efficiency, resulting in 
increased sizing property. 
TABLE 13 
______________________________________ 
HST Sizing 
Amount of 
Method of 
Property: 
Sizing Agent Sizing Addition: 
directly after 
and Amount Enhancer Sizing Agent 
paper 
Added Sizing Added and Sizing 
was made 
(wt %) Enhancer (wt %) Enhancer 
(sec) 
______________________________________ 
Precis .RTM. 2000 
None 0 NA 2 
0.08 
Precis .RTM. 2000 
Example 1 0.023 Separate 
28 
0.08 Copolymer 
Precis .RTM. 2000 
Example 1 0.023 Preblended 
32 
0.08 Copolymer 
Precis .RTM. 2000 
Copolymer 0.047 Separate 
109 
0.08 from 
Example 1 
Precis .RTM. 2000 
Example 1 0.047 Preblended 
109 
0.08 Copolymer 
Precis .RTM. 2000 
Example 1 0.095 Separate 
195 
0.08 Copolymer 
Precis .RTM. 2000 
Example 1 0.095 Preblended 
197 
0.08 Copolymer 
______________________________________ 
EXAMPLE 37 
In this Example, the sizing enhancer of this invention was used as a sizing 
enhancer in a paper system that ordinarily exhibits sizing reversion, 
i.e., loss of sizing property over a period of time. The sizing enhancer 
employed was polymerization reaction product prepared as described in 
Example 1. 
The paper employed in this Example was similar to that described for 
Example 24 but with some differences. 
The pilot Fourdrinier papermaking machine was operated with a paper furnish 
of 70:30 bleached hardwood:bleached softwood beaten to 425 mL Canadian 
standard freeness. Additives employed included 20 wt % precipitated 
calcium carbonate filler added at the fourth mix box, 0.1 wt % alum added 
at the fan pump inlet, 0.01 wt % retention aid (high weight average 
molecular weight (10.sup.7) acrylate:acrylamide (3:7) polymer) added at 
the fan pump outlet, 0.4 wt % cationic starch and paper sizing agent added 
at the second mix box, and sizing enhancer added at the first mix box. 
System pH was maintained at 8.2. 
The commercial sizing agent used was Precis.RTM. 2000 sizing agent and this 
was used at two use levels, 0.08 wt % and 0.10 wt %. The sizing enhancer 
was employed at two concentrations, ranging between 0.04 wt % to 0.1 wt %, 
for each of the sizing agent use levels, as shown in Table 14 below. 
Controls with sizing agent at three use levels, ranging from 0.10 wt % to 
0.16 wt %, but without any sizing enhancer being present, were also 
included in the evaluation. 
Table 14 below summarizes the results, measured as Hercules Size Test 
measurements taken immediately after the sized paper was made and also 
four weeks later for the aged sized paper. As shown by the data for the 
controls, sized paper lacking a sizing enhancer lost 59-71% of its initial 
sizing property after being aged for four weeks. The results obtained for 
the evaluation with sizing enhancer being present demonstrate several 
advantages associated with the use of the polymerization reaction product 
of this invention: 
(i) the initial sizing property benefit is increased when the sizing 
enhancer is present 
(ii) the extent of loss, i.e., percentage reduction, of sizing property is 
significantly reduced; and 
(iii) the rate of loss of sizing property is retarded. 
TABLE 14 
__________________________________________________________________________ 
HST Sizing 
HST Sizing 
Amount of 
Property: 
Property: 
Percentage 
Sizing 
directly 
after Reduction 
Sizing Agent and 
Enhancer 
after paper 
paper aged 
in Sizing 
Amount Added 
Sizing Added was made 
4 weeks 
Property 
(wt %) Enhancer 
(wt %) 
(sec) (sec) (after 4 weeks) 
__________________________________________________________________________ 
Precis .RTM. 2000 
None 0 7 2 71 
0.10 
Precis .RTM. 2000 
None 0 22 8 64 
0.12 
Precis .RTM. 2000 
None 0 39 16 59 
0.16 
Precis .RTM. 2000 
Example 1 
0.04 85 67 21 
0.08 Copolymer 
Precis .RTM. 2000 
Example 1 
0.08 153 133 13 
0.08 Copolymer 
Precis .RTM. 2000 
Example 1 
0.05 153 119 22 
0.10 Copolymer 
Precis .RTM. 2000 
Example 1 
0.1 226 205 9 
0.10 Copolymer 
__________________________________________________________________________ 
EXAMPLE 38 
This Example demonstrates that the sizing enhancer of this invention may be 
employed with a rosin-based sizing agent, to enhance sizing performance. 
The sizing agent was PFP 50 sizing agent (Hercules Incorporated, 
Wilmington, Del.), a rosin paste sizing agent. For comparison, Reten.RTM. 
203 sizing agent was also used. 
The internal addition procedure, described in the Papermaking General 
Procedure above, was followed using the following additives and addition 
points. The pilot Fourdrinier papermaking machine was operated with a 
paper furnish of 70:30 bleached hardwood:bleached softwood beaten to 417 
mL Canadian standard freeness. Additives employed included 10 wt % clay 
filler added at the machine chest. 0.4 wt % alum added at the second mix 
box, 0.5% cationic starch added at the third mix box, and 0.025 wt % 
retention aid (7:93 mole ratio copolymer of 
2-acryloyloxyethyltrimethylammonium chloride and acrylamide) added at the 
fan pump outlet, paper sizing agent added at the third mix box and sizing 
enhancer added at the first mix box. The papermaking pH was 6.5. The 
papermaking furnish was warmed to 54.degree. C. with steam at the constant 
level chest. 
Table 15 below summarizes the results, measured as Hercules Size Test 
measurements taken immediately after the sized paper was made. The results 
demonstrate the superior sizing property obtained with the polymerization 
reaction product of this invention, when used with a rosin-based sizing 
agent. 
TABLE 15 
______________________________________ 
Amount of 
Sizing Agent Sizing 
and Amount Enhancer HST Sizing 
Added Sizing Added Property 
(wt %) Enhancer (wt %) (sec) 
______________________________________ 
PFP 50 None 0 4 
0.40 
PFP 50 None 0 17 
0.67 
PFP 50 Reten .RTM. 203 
0.1 72 
0.40 
PFP 50 Copolymer 0.1 130 
0.40 from 
Example 1 
PFP 50 Reten .RTM. 203 
0.2 194 
0.40 
PFP 50 Copolymer 0.2 334 
0.40 from 
Example 1 
______________________________________ 
It will be appreciated by those skilled in the art that changes could be 
made to the embodiments described above without departing from the broad 
inventive concept thereof. It is understood, therefore, that this 
invention is not limited to the particular embodiments disclosed, but it 
is intended to cover modifications within the spirit and scope of the 
present invention as defined by the appended claims.