Note: Descriptions are shown in the official language in which they were submitted.
~ 26S Dumas Case 6
This inYention relates to the production of sized paper and
sized paperboard.
In particular, this invention relates to the manufacture of
sized paper and sized paperboard wherein the sizing agent employed
is a hydrophobic cellulose reactive sizing agent such as a ketene
dimer sizing agent and there is employed in combination therewith
a new sizing accelerator to provide higher off-the-machine sizing
` than when the cellulose reactive sizing agent is used alone.
United Kingdom patent specification 1,373,788 discloses the
lO use of a dicyandiamide-formaldehyde condensate in combination with
a ketene dimer sizing agent to provide sized paper and sized paper-
board having a higher degree of sizing than that obtained by using
` the same quantity of the ketene dimer sizing agent alone.
In accordance with this invention there is provided a
method for sizing paper and paperboard with a hydrophobic cellulose
` reactive sizing agent, which method comprises using in combination
with the sizing agent a novel sizing accelerator therefor, said
sizing accelerator being a nitrogen containing condensation product
obtained by reacting an epihalohydrin with a condensate derived by
20 condensing dicyandiamide or cyanamide with a polyalkylene poly-
amine.
Further, and in accordance with this invention, there is
provided a novel sizing composition for use in sizing paper and
; paperboard from cellulose stock. The novel sizing composition is
comprised of (~) a hydrophobic cellulose reactive sizing agent
; such as a ketene dimer~ an acid anhydride, an organic isocyanate,
and mixtures of two or more, and (B) a nitrogen-containing conden-
sation product obtained by reacting an epihalohydrin with a conden-
sate derived by condensing dicyandiamide or cyanamide with a poly-
30 alkylene polyamine.
The preferred sizing compositions will be aqueous emulsions
comprised of the cellulose reactive sizing agent, an emulsifier,
and the nitrogen-containing condensation product. The term "emul-
sion" is used herein, as is customary in the art, to mean either a
- 2 - ~
265
di~persion of the liquid-in-}iquid type or of the solid-in-liquid
type.
Aqueous emulsions of hydrophobic cellulose reactive sizing
agents are known in the art and are commercially available. To
prepare the novel sizing compositions of this invention there is
thoroughly admixed with the emulsion an amount of sizing acceler-
ator sufficient to increase the sizing action of the sizing agent.
It has been determined that from 0.25 part to 8 parts by weight
for each part by weight of the hydrophobic cellulose reactive siz-
10 ing agent present in the emulsion provides good results.
Thus, the novel sizing comositions of this invention areaqueous emulsions that consist essentially of a hydrophobic cellu-
lose reactive sizing agent, such as a ketene dimer, the nitrogen-
containing condensation product in an amount sufficient to increase
the sizing action of the sizing agent, and an emulsifier. The
amount of emulsifier employed will be that sufficient to obtain
and maintain an emulsion that is stable for a prolonged period of
time and is within the skill of the art.
The emulsifier employed can be chosen from the emulsifiers
20 conventionally employed in the production of em~lsions of cellu-
lose reactive sizing agents. Such emulsifiers are well known in
the art and include cationic starches that are water-soluble
starches carrying sufficient cationic amino groups, quaternary
ammonium, or other cationic groups to render the starch, as a
, whole, cellulose-substantive. An example of such a cationic
starch is the cationic amine modified starch described in U.K.
patent specification 903,416.
Another emulsifier that can be used is a water-soluble cat-
ionic thermosetting resin obtained by reacting epichlorohydrin
30 with a water-soluble aminopolyamide formed from a dicarboxylic
acid and a polyalkylene polyamine. Resins of this type are des-
cribed in U.K. patent specification 865,727.
The nitrogen-containing condensation products used in this
invention are obtained by reacting an epihalohydrin with a poly--
-- 3 --
.
Z~i5
condensate formed by condensing dicyandiamide or c~anamide with a
polyalkylene polyamine, both reactions be~ng carried out at ele-
vated temperatures.
Nitrogen-containing condensation products suitable for use
in this invention are described in U.K. patent specification
1,125,486.
The epihalohydrin can be epibromohydrin, epichlorohydrin
being preferred. The epihalohydrin can be prepared in situ, if
desired, by employing a glycerol dihalohydrin such as glycerol di-
10 chlorohydrin.
The polyalkylene polyamine employed in preparing the poly-
condensate is represented by the formula
R
. H2NCnH2n (NCnH2n) XNH2
where R is hydrogen or Cl-C4 alkyl; n is an integer 2 through 6
and x is an integer 1 through 4. Examples of Cl-C4 alkyl are
methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl and t-butyl.
Specific examples of the polyalkylene polyamines of the
above formula include diethylenetriamine; triethylenetetramine,
20 tetraethylenepentamine; dipropyltriamine; dihexamethylenetriamine;
pentaethylenehexamine; and methyl bis(3-aminopropyl)amine.
The nitrogen-containing condensation products are obtained
.. :
by first condensing, at an elevated temperature, dicyandiamide or
cyanamide with a polyalkylene polyamine, as above described, to
produce a polycondensate. For each primary amino group of the
polyalkylene polyamine, 0.1 to 1 mol, preferably 0.4 to 0.6 mol,
of dicyandiamide is employed. When cyanamide is employed, it is
employed in an amount of 0.2 mol to 2 mols, preferably 0.8 mol to
1.2 mols, for each primary amino group of the polyalkylene poly-
30 amine. The polycondensate thus obtained is reacted, preferably
at an elevated temperature, with an epihalohydrin using 0.3 mol to
5.5 mols, preferably 1 mol to 1.5 mols, of epihalohydrin for each
secondary or tertiary amino group of the polyalkylene polyamine
used in preparing the polycondensate.
_ 4 _
110~265
In the manufacture of the polycondensates, dicyandiamide or
cyanamide is heated with the polyalkylene polyamine at a tempera-
ture from about 100C. to about 200C., preferably from ahout
150C. to about 170C. In the course of the reaction, for every
mol of dicyandiamide 2 mols of ammonia is produced and for every
mol of cyanamide one mol of ammonia is produced.
As a rule it is not necessary to perform this condensation
in the presence of a solvent because the reactants dissolve one in
the other at the reaction temperatures employed; however, if de-
10 sired, an inert solvent, such as ethyleneglycol monoalkyl ether ordialkyl ether, or diethyleneglycol monoalkyl or dialkyl ether may
be used.
The reaction of the polycondensate with epihalohydrin is
preferably performed in an aqueous solution or dispersion. If de-
sired, another medium, for example acetone or an alcohol such as
methanol or ethanol, or mixtures thereof with water can be used.
The reaction with epihalohydrin is carried out at an elevated tem-
perature, preferably at 60C. to 100C. As soon as the reaction
mixture shows signs of an impending gelation, the reaction is in-
20 terrupted by adding an acid or by dilution with water, or by both.
Depending on the polyalkylene polyamine used and the ratioof polyalkylene polyamine to dicyandiamide or cyanamide and epi-
chlorohydrin chosen, the nitrogen-containing condensation products
are readily soluble or only dispersible in water.
The stability of the aqueous solutions can be substantially
increased by adjusting them to an acid pH value. Furthermore, im-
proved stability is also achieved by diluting the aqueous solutions
so that, for example with a 20% solution at a pH value lrom 4.8 to
5 at room temperature a stability of 3 to 4 months is ensured.
Percentages in the following examples are percentages by
weight.
Example 1
Dicyandiamider 252 grams (3 mols), is added to 309 grams (3
mols) of diethylenetriamine contained in a reaction vessel fitted
-- 5 --
110~265
~ith thermometer, agitator and reflux condenser. The resulting
mixture is heated to 120C.-140C. and ammonia, a reaction product,
is released. The reaction takes an exothermic course, with the
temperature rising to about 160C. This temperature is maintained
for about 1 hour. The amount of ammonia eliminated during reac-
tion is 5-6 mols. The reaction mass is subsequently cooled by add-
ing water in an amount sufficient to provide a solids content of
about 25%. Epichlorohydrin, 358.8 grams (3.9 mols), is then added
slowly so that the temperature of this reaction mass rises to 55-
10 60C. This temperature is maintained until the viscosity of thereaction mass reaches H on the Gardner-Holdt scale. The reaction
is terminated by adding water in an amount sufficient to provide a
solids content of 20%. The resulting solution is adjusted to a pH
of 5 by adding formic acid.
Example 2
Dicyandiamide, 252 grams (3 mols), is added to 438 grams (3
mols) of triethylenetetramine contained in a reaction vessel
fitted with thermometer, agitator and reflux condenser. The re-
sulting mixture is heated to 120-140C. and ammonia, a reaction
- 20 product, is released. The reaction takes an exothermic course,
with the temperature rising to about 160C. This temperature is
maintained for about 1 hour. The amount of ammonia eliminated
during reaction is 4-5 mols. The reaction mass is subsequently
diluted by adding 400 grams of water. The resulting solution has
a solids content of 59.5~. 336 grams of this solution is diluted
to a 25% solids content by adding 464 grams of water. Epichloro-
hydrin, 110 grams (1.2 mols), is then added slowly over a period
of 15 minutes during which time the temperature of this reaction
mass rises to 70C. This temperature is maintained for 44 minutes
30 as the viscosity of the reaction mass increases to N on the
Gardner-Holdt scale. The reaction is terminated by immediately
adding 680 grams of water and the pH of the solution is adusted to
a pH of 4.5 by adding 22 grams of concentrated formic acid. The
resulting solution has a solids content of 21.1%.
-- 6 --
110~)265
Example 3
Dicyandiamide, 168 grams ~2 mols), is added to 290 grams (2
mols) of methyl bis~3-aminopropyl)amine contained in a reaction
vessel fitted with thermometer, agitator and reflux condenser. The
resulting mixture is heated to 220C. and maintained at this tem-
perature for 1 hour. Then 350 grams of water is added to provide
- a solution having a solids content of 44.9~. 768 grams (345 grams
solids, 2 equivalents) of this solution is diluted to a solids
content of 20% with 957 grams of water. Epichlorohydrin, 966
10 grams (10.5 mols), is then added slowly. The temperature of the
reaction mass is maintained at 80C. until the viscosity thereof
reaches N on the Gardner-Holdt scale. The reaction is terminated
by adding 3862 grams of water and the solution is adjusted to a pH
of 5 by adding 61 grams of concentrated formic acid. The result-
ing solution has a solids content of 17%.
Acid anhydrides useful as cellulose reactive sizing agents
for paper are well known in the art and include (A) rosin anhy-
dride, see U.S. patent 3r582,464; (B) anhydrides having the struc-
ture ~o
R -C
1 \ O (I)
Rl-C ~
where R1 is a saturated or unsaturated hydrocarbon radical, the
hydrocarbon radical being a straight or branched chain alkyl radi-
cal, an aromatic substituted alkyl radical, or an alkyl substitu-
ted aromatic radical so long as the hydrocarbon radical contains a
total of from about 14 to 36 carbon atoms; and (C) cyclic dicar-
30 boxylic acid anhydrides having the structure
'!
; , , ,C ~ (II)
``"`C/
o
where R' represents a dimethylene or trimethylene radical and
where R" is a hydrocarbon radical containing more than 7 carbon
atoms which are selected from the group consisting of alkyl,
~ 7 _
265
alkenyl, aralkyl or aralkenyl. Substituted cyclic dicarboxylic
acid anhydrides falling within the above formula (II) are substi-
tuted succinic and glutaric anhydrides. In formula (I) above each
; Rl can be the same hydrocarbon radical or each Rl can be a differ-
ent hydrocarbon radical.
Specific examples of anhydrides of formula (I) are myrist-
oyl anhydride, palmitoyl anhydride, oleoyl anhydride and stearoyl
anhydride.
Specific examples of anhydrides of formula (II) are iso-
10 octadecenyl succinic acid anhydride, n-hexadecenyl succinic acid
anhydride, dodecyl succinic acid anhydride, decenyl succinic acid
anhydride, octenyl succinic acid anhydride, and heptyl glutaric
acid anhydride.
Hydrophobic organic isocyanates used as sizing agents for
paper are well known in the art. Best results are obtained when
the hydrocarbon chains of the isocyanates contain at least 12 car-
bon atoms, preferably from 14 to 36 carbon atoms. Such isocyan-
ates include rosin isocyanate, dodecyl isocyanate, octadecyl iso-
cyanate, tetradecyl isocyanate, hexadecyl isocyanate, eicosyl iso-
20 cyanate, docosyl isocyanate, 6-ethyldecyl isocyanate, 6-phenyl-
- decyl isocyanate and polyisocyanates such as 1,18-octadecyl diiso-
cyanate and 1,12-dodecyl diisocyanate, wherein one long chain alkyl
group serves two isocyanate radicals and imparts hydrophobic prop-
erties to the molecule as a whole.
Ketene dimers used as cellulose reactive sizing agents are
dimers having the formula
[R'''CH=C=O]2
where R''' is a hydrocarbon radical, such as alkyl having at least
8 carbon atoms, cycloalkyl having at least 6 carbon atoms, aryl,
30 aralkyl and alkaryl. In naming ketene dimers, the radical R''' is
named followed by "ketene dimer". Thus, phenyl ketene dimer is:
[ ~ -~H=C=O~
110~26S
benzyl ketene dimer~ r
¦~3CH2--CH=C=O
and decyl ketene dimer is ~CloH21-CH=C=O~2. Examples of ketene
dimers include octyl, decyl, dodecyl, tetradecyl, hexadecyl, octa-
decyl, eicosyl, docosyl, tetracosyl, phenyl, benzyl beta-naphthyl
and cyclohexyl ketene dimers, as well as the ketene dimers pre-
pared from montanic acid, naphthenic acid, ~9,10-decylenic acid,
~9,10-dodecylenic acid, palmitoleic acid, oleic acid, ricinoleic
acid, linoleic acid, linolenic acid and eleostearic acid, as well
10 as ketene dimers prepared from naturally occurring mixtures of
fatty acids such as those mixtures found in coconut oil, babassu
oil, palm kernel oil, palm oil, olive oil, peanut oil, rape oil,
beef tallow, lard (leaf) and whale blubber. Mixtures of any of
the above named fatty acids with each other may also be used.
Example 4
An emulsion of a ketene dimer prepared from a mixture of
palmitic and stearic acids is prepared by admixing 880 parts of
water, 60 parts of cationic corn starch and 10 parts of sodium
lignin sulfonate. The mixture is adjusted to pH of about 3.5 with
20 98% sulfuric acid. The resulting mixture is heated at 90-95C. for
for about one hour. Water is then added to the mixture in an
amount sufficient to provide a mixture of 1750 parts (total weight).
About 240 parts of the ketene dimer is stirred into the mixture
together with 2.4 parts of thiadiazine. The thiadiazine is used
as a preservative. The resulting premix (at 65C.) is homogenized
in one pass through an homogenizer at 4000 p.s.i. The homogenized
product is diluted with water to a ketene dimer solids content of
about 6%.
Example 5
Example 4 is repeated with the exception that there is em-
ployed the ketene dimer of oleic acid in place of the ketene dimer
prepared from a mixture of palmitic and stearic acids.
As is well known in the art, hydrophobic cellulose reactive
sizing agents are used in the internal sizing of paper and in the
_ g _
2~i5
`" external sizing of paper. The accelerator of this invention can
~e used in combination with the sizing agent in either method.
EXa~ple 6
The product of Example 4 is diluted with water to a ketene
dimer content of 0.10%.
Example 7
The product of Example 5 is diluted with water to a ketene
dimer content of 0.10%.
Example 8
The products of Example 4 and Example 1 are combined, with
addition of water as required, to provide an aqueous sizing compo-
sition comprised of 0.10% ketene dimer of Example 4 and 0.20% of
the nitrogen-containing condensation product of Example 1.
Example 9
The products of Example 4 and Example 1 are combined, with
addition of water as required, to provide an aqueous sizing compo-
sition comprised of 0.10% ketene dimer of Example 4 and 0.10% of
the nitrogen-containing condensation product of Example 1.
Example 10
The products of Example 4 and Example 2 are combined, with
addition of water as required, to provide an aqueous sizing compo-
sition comprised of 0.10% ketene dimer of Example 4 and 0.10% of
the nitrogen-containing condensation product of Example 2.
Example 11
The products of Example 4 and Example 3 are combined, with
addition of water as required, to provide an aqueous sizing compo-
sition comprised of 0.10% ketene dimer of Example 4 and 0.10% of
the nitrogen-containing condensation product of Example 3.
Example 12
The products of Example 5 and Example 1 are combined, with
addition of water as required, to provide an aqueous sizing compo-
sition comprised of 0.10% ketene dimer of Example 5 and 0.10~ of
the nitrogen-containing condensation product of Example 1.
The above sizing compositions are applied to the surface
of a sheet of 40 lb./3000 ft.2 waterleaf paper. The sheet is made
-- 10 --
110~265
from a 50:50 hard~ood:softwood pulp blend on a pilot paper mach-
ine. Each sizing composition is adjusted to pH 7 before appli-
cation to the sheet in the nip of a horizontal size press. The
size press runs at 40 ft./min. and the wet pickup is 70~. Reten-
tion of the ketene dimer size is the same in all of these runs.
The sized sheets are dried at 200F. for 20 sec. on a laboratory
drum drier to 4% moisture. The sizing is measured by the Hercules
Size Te~t with test solution No. 2 to the indicated reflectance.
The off-machine data are obtained within two minutes of drying and
10 the natural aged data after at least 3 days storage at room tempe-
rature. It is known in the art that ketene dimer size develops
substantially all its sizing properties in the paper in 3 days.
After this time the size properties of the paper remain essentially
the same.
Size results are set forth in Table I below.
Table I
Sizing Hercules Size Test
CompositionOff-The-MachineNatural Aged
of Example to 80~ Reflectance to 85% Reflectance
6 0 330
7 450
8 180 300
9 (lst trial) 335 500
9 (2nd trial) 200 536
9 (3rd trial) 160 600
202 455
11 125 460
12 250 500
Example 13
An emulsion of stearic anhydride is prepared by first ad-
mixing 880 parts of water, 60 parts of cationic corn starch and
10 parts of sodium lignin sulfonate. The mixture is adjusted to
- pH of about 3.5 with 98% sulfuric acid. The resulting mixture is
30 heated at 90-95C. for about one hour. Water is then added to
the mixture in an amount sufficient to provide a mixture of 1750
parts (total weight). The temperature of the mixture is adjusted
to 70C. About 240 parts of stearic anhydride is stirred into the
mixture together with 2.4 parts of thiadiazine. The thiadiazine
- 11 -
11t)~265
" is used as a preservative. The resulting premix (at 70C.) is
homogenized in one pass through an homogenizer at 4000 p.s.i. The
homogenized product is diluted ~ith water to a stearic anhydride
solids content of about 6%.
Example 14
An emulsion of iso-octadecenylsuccinic anhydride is pre-
pared by first admixing 880 parts of water, 60 parts of cationic
corn starch and 10 parts of sodium lignin sulfonate. The mixture
is adjusted to pH of about 3.5 with 98% sulfuric acid,. The resul-
10 ting mixture is heated at 90-95C. for about one hour. Water is
then added to the mixture in an amount sufficient to provide a
mixture of 1750 parts (total weight). About 240 parts of iso-
octadecenylsuccinic anhydride is stirred into the mixture together
with 2.4 parts of thiadiazine. The thiadiazine is used as a pre-
servative. The resulting premix, at room temperature, is homo-
genized in one pass through an homogenizer at 4000 p.s.i. The
homogenized product is diluted with water to an anhydride solids
content of about 6~.
Example 15
An emulsion of octadecyl isocyanate is prepared by first
admixing 880 parts of water, 60 parts of cationic corn starch and
10 parts of sodium lignin sulfonate. The mixture is adjusted to
pH of about 3.5 with 98% sulfuric acid. The resulting mixture is
heated at 90-95C. for about one hour. Water is then added to
the mixture in an amount sufficient to provide a mixture of 1750
parts (total weight). About 240 parts of octadecyl isocyanate is
stirred into the mixture together with 2.4 parts of thiadiazine.
The thiadiazine is used as a preservative. The resulting premix,
at room temperature, is homogenized in one pass through an homo-
30 genizer at 4000 p.s.i. The homogenized product is diluted with
water to an octadecyl isocyanate solids content of about 6%.
Example 16
The product of Example 13 is diluted with water to a stearic
anhydride content of 0.20%.
~lO~)Z6S
'Ex'ample' 17
The product of Example 14 is diluted with water to an iso-
' octadecenylsuccinic anhydride content of 0.20%.
Example 18
The product of Example 15 is diluted with water to an octa-
decyl isocyanate content of 0.20%.
Example 19
The product of Example 13 and a nitrogen-containing conden-
sation product prepared in accordance with Example 1 are combined,
10 with addition of water as required, to provide an aqueous sizing
composition comprised of 0.20% stearic anhydride and 0.20% of the
nitrogen-containing condensation product.
Example 20
'~ The product of Example 14 and a nitrogen-containing conden-
sation product prepared in accordance with Example 1 are combined,
with addition of water as required, to provide an aqueous sizing
composition comprised of 0.20~ iso-octadecenylsuccinic anhydride
and 0.20% of the nitrogen-containing condensation product.
Example 21
' 20 The product of Example 15 and a nitrogen-containing conden-
sation product prepared in accordance with Example 1 are combined,
with addition of water as required, to provide an aqueous sizing
composition comprised of 0.20% octadecyl isocyanate and 0.20%
nitrogen-containing condensation product.
The above sizing compositions of Examples 16-21 are applied
to the surface of a sheet of 40 lb./3000 ft.2 waterleaf paper.
' The sheet is made from a 50:50 hardwood:softwood pulp blend on a
pilot paper machine. Each sizing composition is adjusted to pH 7
before application to the sheet in the nip of a horizontal size
30 press. The size press runs at 40 ft./min. and the wet pickup is
70%. Retention of the size is the same in all of these runs. The
sized sheets are dried at 200F. for 20 sec. on a laboratory drum
drier to 4% moisture. The sizing is measured by the Hercules Size
Test with test solution No. 2 to the indicated reflectance. The
- 13 -
265
~~ off-machine data are o~tained within two minutes of drying and the
natural aged data after at least 3 days storage at room tempera-
ture.
Size results are set forth in Table II below.
Table II
Sizing
Composition Hercules Size Test to 80~ Reflectance
of ExampleOff The Machine Natural Aged
16 0 451
17 460 882
18 0 602
19 732 920
0 620
21 325 930
It is well known in the art that the hydrophobic cellulose
reactive sizing agents provide little, if any, off-the-machine
sizing. The above examples, directed to surface sizing, show that
the sizing compositions of this invention provide substantial
improvement in off-the-machine sizing.
The sizing compositions of this invention can be used in
the internal sizing of paper with improved sizing results.
While it is preferred to use the compositions of this in-
vention in the internal sizing of paper, it is to be understood
that the hydrophobic cellulose reactive sizing agent and the siz-
ing accelerator can be separately added if desired.
The above description and examples are illustrative of
this invention and not in limitation thereof.
.
