Note: Descriptions are shown in the official language in which they were submitted.
11~791 ~
This invention relates to a method of preparing aque-
ous dispersions of fortified rosin, to the aqueous disper-
sions thus prepared, and to their use in the manufacture of
sized paper products.
Internal sizing of paper with rosin is discussed by
Casey, Pulp and Paper, Second Edi~ion, Volume II:
Papermaking, Chapter XIII, pages 1043-1066, reference to
which is hereby made.
At page 1048 Casey discusses fortified rosin size and
states that fortified rosin sizes are made by reacting ma-
~; leic anhydride or other dienophiles with rosin to increase
` the number of carboxylic acid groups. Casey also states
that a typical fortified size may contain about 1% to 30%
of maleopimaric acid anhydride.
Casey, at page 1047, under the heading "Free Rosin
Size", states that the relative merits of high free rosin
size and low free rosin size has been a controversial sub-
ject for many years but that it is now pretty generally
recognized that high free rosin size results in better siz-
ing and uses less alum.
At page 1050, under the heading "Protected Rosin
~ Size", Casey states that by using a protective colloid it
; is possible to prepare highly stable size containing as
high as 90% free rosin. At page 1051 Cases discusses the
Bewoid process for preparing a high free rosin size and
states that Bewoid size, as usually prepared, containing
about ~0% free rosin dispersed in a small amount of rosin
soap and stabilized by the presence of about 2% casein or
other protein. The casein is used as a protective colloid
to prevent growth of rosin particles, thereby maintaining
- them in a state of fine subdivision.
'
' ~
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Casey states further that the Bewoid process involves
the mechanical subdivision of rosin in the presence of
about I to 2% sodium hydroxide and about 2% casein. The
rosin is heated and subjected to mechanical shearing stress
unti~ it is subdivided into small particles. A small
amount of caustic soda (1.6 parts per 100 parts of rosin)
is then added to the melted rosin to saponify part of it,
and then casein (2.0 parts casein dispersed in 0.2 part
caustic) is added to stabilize the dispersed particles of
rosin. The dissolved casein is run into the molten rosin
under vigorous agitation, after which an additional small
amount of caustic (0.2 part) is added or the hot rosin melt
is injected into water containing casein. Water is finally
added to produce a finished dispersion containing about 45%
solids, which is used in this form. This method is some-
times referred to in the art as the "inversion process of
preparing rosin size" and the rosin size thus produced re-
ferred to as "invert size".
Using the inversion process, Mashburn, U.S. patent
2,393,179 prepared a free rosin size using a nonalkaline
dispersing agent, such as sulfonated higher fatty alcohol,
in place of sodium hydroxide. The rosin is melted and the
desired amount of dispersing agent is added with sufficient
agitation to form a homogeneous molten mass. A substanti-
ally neutral or slightly acid aqueous solution or disper-
sion of a protective colloid, such as casein, is then added
gradually with rapid stirring whereby there is produced a
high solids paste-type dispersion which is then diluted
with water to a solids content of 40~ to 60% by weight.
Casey, at pages 1051 and 1052, discusses the Prosize
process for producing a protecte~ size containing a high
free rosin content. The rosin particles are prevented
from growing into larger aggregates by the presence of a
surface-active protein such as soybean protein.
German patent 1,131,348 states that free rosin sizes
are dispersions of unsaponified resin acids with a certain
percentage of rosin soap. The dispersions are prepared by
the inversion process. They are mostly used with free
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rosin content of 60% to 95% and contain besides rosin aux-
iliary emulsifiers and stabilizers such as stearates, tri-
ethanolamine, casein and waxes.
German patent 1,131,348 further states that, hereto-
fore, the fortified rosins have not been suitable for thepreparation of dispersions since ~hey have mostly too high
melting points, have a tendency to crystallization, or
form, during dispersing, fine crusts which lead to sedimen-
tation pheno~ena. German patent 1,131,348 discloses and
claims a paper size and a process for the preparation of a
paper size in the form of an aqueous dispersion with a
high free rosin content from fortified rosin characterized
in that the fortified rosin is mixed with fatty acids,
fatty acid mixtures, and/or naphthenic acids at elevated
temperatures and that the dispersion is carried out in the
known manner. The process used in this patent is the in-
version process.
U.S. patent 3,565,755 discloses a substantially homo-
geneous stable aqueous suspension of rosin-base material in
a state of fine subdivision. The rosin-base material can
be all fortified rosin or it can be a rosin-fortified rosin
mixture. A very small amount of the rosin-base material is
saponified and functions as dispersing agent for the rosin-
base particles. This composition, which consists essenti-
ally of the rosin-base material, the saponified rosin-base
material, and water, is used in the sizing of paper. The
size of patent 3,565,755 is a high free rosin size in that
it contains only a very small amount of saponified rosin-
base material. Further, it has good stability (good shelf
life) for prolonged periods of time and does not require
the use of stabilizers heretofore used in the preparation
of stable high free rosin sizes such, for example, as
casein and soybean protein.
In the process of U.S. patent 3,565,755, a material
such as a salt of rosin or a salt of fortifed rosin, or an
alkaline material, such as sodium hydroxide, is dissolved
in water. The resulting aqueous solution is mixed with a
solution of a water-immiscible organic solvent such as
o
benzene, which has dissolved therein fortified rosin. The
resulting mixture is homogenized to produce a stable emul-
sion and then the organic solvent is removed to provide a
stable aqueous dispersion.
Australian Patent Application 69365/74, filed May 24,
1974, discloses a process for preparing an essentially
stable aqueous dispersion of rosin-base material useful in
the sizing of cellulosic papermaking fibers which comprises
homogenizing under a pressure of from about 2000 p.s.i.g.
to about 8~00 p.s.i.g. and at a temperature of from about
150C. to about 195C. an unstable aqueous dispersion
containing, by weight, at least 5~ solids, the solids con-
sisting essentially of, by weight, from 0~ to about 95%
rosin and from 100% to 5% of an adduct reaction product of
rosin and an acidic compound containing the ~ C=O
group, the amount of adducted acidic compound being from
about 1% to about 20~ of the total solids weight, charac-
terized in that the process is carried out in the presence ~-
-~ of an anionic dispersing agent. The anionic dispersing
agent can be saponified rosin base material, sodium alkyl
benzene sulfonate, sodium naphthalene sulfonic acid,
sodium lauryl sulfate, and the ammonium salt of the
sulfate ester of an alkylphenoxy(polyethyleneoxy)ethanol.
~ Swedish Patent Application 7410018-1 discloses a sub-
`~ 25 stantially stable aqueous dispersion, consisting essenti-
ally of water, rosin material, and as a stabilizer for the
rosin material an alkali metal alkyl benzene sulfonate,
said alkyl benzene sulfonate heing present in an amount
sufficient to stabilize said rosin material. The disper-
sions are prepared by passing a prepared mixture of the
components through an homogenizer.
U.S. Patent 3,906,142 of September 16, 1975, dis-
closes an agent for sizing paper without the use of alum-
inum sulfater which comprises a stable aqueous dispersion
of fortified rosin, fortified by reaction with an alpha,
beta unsaturated carboxylic acid or anhydride; a protec-
~-~ tive colloid, such as casein; and a volatile base, such as
ammonia; at least 90% of said fortlfied rosin being
... . .
5_
unsaponified.
The method used in U.S. Patent 3,906,142 is the in-
version process for preparing size and consists of melting
fortified rosin in a vessel provided with stirring and
heating mechanism. A dispersing and stabilizing agent ls
then prepared in a separate vessel by dissolving a measured
quantity of a protective colloid, such as casein, and a
measured quantity of a volatile base, such as ammonia in
water. The next step in the manufacture of the sizing
agent is to add quickly, to the molten rosin, the prepared
dispersing and stabilizing agent, making use of high speed
stirring or other intensive agitation of the mixture, dur-
ing and after addition. The solids content of the resul-
tant aqueous rosin dispersion is then adjusted by adding a
calculated quantity of water thereto.
In accordance with this invention there is provided
a method for preparing aqueous dispersions of fortified
rosin by the inversion process wherein the use of protec-
tive colloids, such as casein, heretofore used in the
invention process is not essential.
This invention provides, in the inversion process of
preparing paper size from fortified rosin wherein molten
fortified rosin and water containing a dispersing agent are
first mixed to provide an emulsion wherein the molte-n for-
tified rosin is the continuous phase and the water is thedisperse phase and the emulsion is subsequently inverted
by the addition of water to provide an emulsion wherein
the water is the continuous phase and the fortified rosin
is the disperse phase, the improvement wherein there is
employed as the dispersing agent a water-soluble compound
which provides in solution an anion having the formula
R O(cH2cH2o)nclcHcH2
wherein R is a normal or branched chain alkyl containing 4
through 18 carbon atoms, and n is an integer 4 through 25.
The value of n, as used herein, is an average value since,
in the method of preparing the dispersing agents, ethylene
~7~
--6--
oxide condens~tes varying in chain length are obtained in
t~e condensation reaction. Examples of R are butyl, iso-
butyl, penty~, isopentyl, hexyl, isohexyl, octyl, nonyl,
dodecyl, tetradecyl, hexadecyl and octadecyl.
The aqueous dispersions prepared by the method of
this invention will comprise, by weight, from about 5% to
about 70% fortified rosin or fortified rosin blend (forti-
fied rosin blended with unfortified rosin or extender or
both as hereafter described) preferably from about 10% to
55%; from about 1% to about 10% dispersing agent, prefer-
ably from about 2% to about 8%, based on the fortified
rosin or fortified rosin blend; and the balance water to
100%. -
The rosin used to prepare the fortified rosin
employed in this invention can be any of the commercially
available types of rosin, such as wood rosin, gum rosin,
tall oil rosin and mixtures of any two or more, in their
crude or refined state. Rosins which have a tendency to
crystallize may be treated, at elevated temperatures, with
formaldehyde or paraformaldehyde in the presence of an
acid catalyst, for example, p-toluene-sulphonic acid, in a
manner known to those skilled in the art. Thus, formalde-
hyde treated rosin can be used to prepare the fortified
rosin and is included in the expression "rosin" as used
herein and in the claims.
The fortified rosin employed is the adduct reaction
product of rosin and an acidic compound-containing the
>C=C,-CI-O group and is derived by reacting rosin and the
acidic compound at elevated temperatures, usually from
about 150C. to about 210C.
The amount of acidic compound employed will be that
amount which will provide fortified rosin containing from
about 1% to about 12% by weight, preferably from about 4%
to about 9% by weight, of adducted acidic compound based
on the weight of the fortified rosin. Methods of
preparing fortified rosin are disclosed and described in
U.S. patents
2,628,918 and 2,684,300, reference to which is hereby made.
Examples of acidic compounds containing the ,C=C~-C=O
o
group that can be used to prepare the fortified rosin in-
clude the alpha-beta-unsaturated organic acids and their
available anhydrides, specific examples of which include
fumaric acid, maleic acid, acrylic acid, maleic anhydride,
itaconic acid, itaconic anhydride, citraconic acid and
citraconic anhydride. The preferred adducting acid is
fumaric acid. Mixtures of acids can be used to prepare the
fortified rosin if desired. Also mixtures of different
fortified rosins can be used if desired. Thus, for ex-
ample, a mixture of the acrylic acid adduct of rosin andthe fumaric acid adduct can be used to prepare the invert
sizes of this invention.
The fortified rosin can be extended, if desired, by
known extenders therefor such as waxes, particularly par-
; 15 affin wax and microcrystalline wax; hydrocarbon resins
including those derived from petroleum hydrocarbons and
terpenes; and the like. This is accomplished by melt
blending or solution blending with the fortified rosin up
to about 100% by weight based on the weight of fortified
rosin of the fortified rosin extender. If an e~tender isto be blended with the fortified rosin, the preferred
amount of extender employed will be from about 30% to about
~ 50% by weight based on the weight of the fortified rosin.
; Also, blends of fortified rosin and unfortified rosin
25 can be used in carrying out this invention as well as
blends of fortified rosin, extender and unfortified rosin.
Fortified rosin-unfortified rosin blends will com-
prise about 25% to about 99% fortified rosin and about 75%
to about 1% unfortified rosin. Blends of fortified rosin,
30 rosin and rosin extender will comprise about 25% to 49%
fortified rosin, about 5% to 50% unfortified rosin and
about 1% to 50% fortified rosin extender.
If rosin (that is, unfortified rosin) is blended with
the fortified rosin, it can be any o tr.ose used in the
35 preparation of the fortified rosin as above set forth. In
addition partially or substantially completely hydrogenated
rosins and polymerized rosins, can be used if desired.
f The dispersing agents used to prepare the dispersions
,.
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of this invention are water-soluble compounds represented
by the ~ormula
~ - O(CH2CH2O)nCfHCH2C-O M (I)
R SO3 M
wherein R and n are as defined hereinbefore.
In formula (I) M is any suitable cation that will
allow substantial dissolution of the dispersing agent in
water.
Preferably M is an alkali metal ion such as potas-
sium, sodium, lithium and cesium; ammonium (NH4+3; and
10 mono-(hydroxyethyl)ammonium. One M can be the hydrogen
ion (H ) if desired.
Water soluble dispersing agents of formula (I) are
prepared by known methods. Thus, for example, ethylene
oxide is condensed with an alkyl phenol, such as octyl
15 phenol, by well-known methods to provide a condensate of
the formula
~, ~\> - O(CH2CH2O3 H
As above set forth, the value of n is an average value
since ethylene oxide condensates varying ir chain length
2Q are obtained in the condensation reaction. The condensate
is then reacted with maleic anhydride or maleic acid and
the resulting reaction product subsequently reacted with a
water-soluble sulfite, such as sodium sulfite, whereby a
water-soluble salt of formula (I) is obtained. Sodium
25 salts of the sulfosuccinate esters of ethylene oxide con-
densates of alkyl phenols are available commercially; a
specific example being that available under the proprietary
designation Aerosol A103.~
In carrying out the process of this invention a known
30 quantity of fortified rosin, together with any desired
extender or unfortified rosin or both, is heated to fusion
in a vessel provided with stirring apparatus and heating
means to provide a fused resinous mass (fused resin). The
r temperature of the fused resin will usually be in the range
~ ~A,9~ R~ ~
.
,
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_9_
of a~out 90 C~ to about 160 C. If low melting extend-
ers are to be b~ended with the fortified rosin, the fused
temperature o~ the blend could be lower than 90C.
A solution of the dispersing agent in water is added
to the fused resin, with continuous stirring of the resin
melt, to form an emulsion in which the water is the dis-
perse phase and the fused resin is the continuous phase.
The amount of dispersing agent in the aqueous solution
will be that sufficient to provide from about 1% to about
10%, preferably, from about 2% to about 8%, b~ weight of
dispersing agent based on the fused resin. The amount of
water employed at this stage is that amount sufficient to
provide an emulsion as above described having a total
solids content of, by weight, from about 70% to 86~, de-
pending upon the particular dispersing agent used and itsconcentration.
Subsequently, additional hot water (inversion water)
at a temperature of about 70C., and higher if desired,
is added with vigorous stirring. At a water to resin
ratio of about 30:70 the emulsion inverts, the water
becoming the continuous phase and the resin becoming the
dispersed phase. On cooling the resin solidifies and
there is provided an aqueous dispersion of finely divided
resin particles. The resin particles will be fortified
rosin particles or particles of fortified rosin blend as
above described. The aqueous dispersion can be diluted to
a lower solids content, if desired, by the addition of
water.
It has been determined that dispersions of this
invention have good stability at a pH of from about 3.0 to
about 5.5. Ad~ustment of the pH can be made by adding an
alkali, preferably sodium hydroxide, to the inversion
water or to the aqueous solution of dispersing agent in an
amount to bring the aqueous dispersion to the desired pH.
It will be understood by those skilled in the art,
that the process of thls invention can be carried out in
an open vessel at atmospheric pressure or under pressure,
in a closed vessel.
0
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As above set forth, the initial temperature of the
fused resin (fortified rosin or fortified rosin blend)
will be in the range of about 90C. to about 160C.
If the process is carried out at atmospheric pressure and
the initial resin temperature is above 100C., the tem-
perature will drop on addition of the aqueous solution of
dispersing agent due to partial evaporation of the water.
If the preparation be carried out in a closed vessel under
steam pressure so that evaporation of the water is re-
tarded, the temperature can be maintained at a level above100C. The rate of addition of the aqueous solution of
dispersing agent and the inversion water and degree of
agitation can be varied over a wide range and is within the
skill of the art. However, the rate of addition of inver-
sion water and degree of agitation are normally speeded upat the point of inversion to insure rapid and complete in-
version to the resin-in-water dispersion. The temperature
at the point of inversion is in the range of about 70C.
to about 150C. and preferably from about 90C. to
about 130C.
The process can also be carried out in two stages by
feeding the molten resin and the hot water solution of the
dispersing agent to a mixer to provide the water-in-resin
dispersion. Subsequently, the water-in-resin dispersion
- 25 and hot inversion water are fed, in separate streams, to a
second mixer maintained at a temperature of about 70C.
to 150C. where the inversion takes place. The result-
ing aqueous dispersion is then recovered from the second
mixer.
Stable resin-in-water dispersions are prepared by
the process of this invention. The particles comprising
the dispersed phase are relatively small, not more than
about 10% of the particles being larger than about 0.4 -
micron.
Example A
This example ~llustrates the preparation of fumaric
acid fortified rosin. Fumaric acid, 8 parts, was adducted,
at a temperature of about 200C. with tall oil rosin, 92
,
79~0
parts. The fumaric acid dissolves in the fused rosin and
reacts therewith to provide fumaric acid fortified rosin.
After substantially all the fumaric acid has reacted with
the rosin, the fortified rosin was cooled to room tempera-
ture (about 23C.).
The following examples illustrate the preparation offortified rosin dispersions in accordance with this inven-
tion. All parts and percentages are by weight unless
otherwise specified.
Example l
Fumaric acid fortified rosin, prepared as in Example
A (lO0 parts), was melted and heated to 145C. in a
baffled stainless steel container. To the stirred molten
fortified rosin was added, over a period of 5 minutes,
about 21 parts of a 23.3~ Aerosol Al03 dispersant solution
in distilled water which had been heated to 95C. Aero-
sol Al03 dispersant is the disodium salt of ethoxylated
nonylphenol (9.5 moles of ethylene oxide per mole of nonyl-
phenol) half-ester of sulfosuccinic acid. Considerable
water evaporated during the addition of the surfactant
solution. The temperature of the mixture, after this addi-
tion was complete, was 95C. Additional 90C. hot
water (20 parts) was added to the stirred mixture to give
a smooth, creamy-white, water-in-resin emulsion of approxi-
mately 80% solids content. 70 parts of 90 C. hot waterwas then added with vigorous stirring over a period of one
minute, causing the emulsion to invert to a resin-in-water `
emulsion, which was rapidly cooled to 30C. The result-
ing aqueous dispersion had a solids content of 51.4%, had
a blue-white appearance, passed completely through a ]00-
mesh screen, and had excellent storage stability. The
product has utility as a paper size.
Example 2
The apparatus employed in this example consisted of
three precision pumps, two in-line mixers, two pressure
receivers, pressure control auxiliaries, and heated tubing
connecting these units. Fumaric acid fortified tall oil
rosin, prepared in accordance with Example A, was heated
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-12-
to about 140C. and pumped into a first mixer, which was
maintained at 125C., at a rate of 4.l2 parts per minute,
where it was mixed with an 11.8% solution of Aerosol A103
dispersiny agent in distilled water heated to 80C. which
was being pumped into said first mixer at a rate of 1.66
parts per minute, to provide a water-in-resin emulsion hav-
ing a solids content of 7U%. This emulsion was pumped into
a second mixer, maintained at 105C., where it was mixed
with distilled water heated to 90C. which was being
pumped into said second mixer at a rate of 3.5 parts per
minute. A resin-in-water emulsion having a solids content
of 45% was formed which was subsequently cooled rapidly to
below 50C.
Example B
Fumaric acid fortified tall oil rosin was prepared
as in Example A with the exception that about 7.5 parts of
fumaric acid was employed and 92.5 parts of tall oil rosin
was employed. The fumaric acid fortified tall oil rosin
had an acid number of 215 and had a combined fumaric acid
content of about 7%.
Example 3
Fumaric acid fortified rosin of Example B (200
parts) was melted and heated to 134C. in a baffled
stainless steel container. To the stirred molten forti-
fied rosin was added, over a period of 5 minutes, 40 partsof a 20% Aerosol A103 dispersant solution in distilled
water which had been heated to 95C. Considerable water
evaporated during the addition of the surfactant solution.
The temperature of the mixture, after this addition was
complete, was 106C. Additional 90C. hot water (80
parts) was added to the stirred mixture to give a smooth,
creamy-white, water-in-resin emulsion of approximately 80%
solids content. 180 parts of 90C. hot water was then
added with vigorous stirring over a period of one minute,
causing the emulsion to invert to a resin-in-water emul-
sion, which was rapidly cooled to 30C. The resulting
aqueous dispersion had a solids content of 45.9~.
- The dispersion of Example 3 was used to surface size
-13- ~7~1~
unsized paper sheets made with 50~ bleached kraft soft
wood and 50~ bleached kraft hard wood pulps to 500 Cana-
dian Standard Freeness, The paper sheets were prepared on
a pilot paper machine at pH 4.5 with 2.5% alum added.
After surface application of the dispersion, the sheets
were drum dried and aged 24 hours before testing. Three
levels of size were applied, as shown in Table I below.
Hercules Sizing Tests show good sizing results. These
data are set forth in Table I.
TABLE I
~ Size Applied Hercules Sizing Test
(based on dry weight of paper)Seconds
0.07 41
0.14 147
0.28 290
It is to be understood that the above description, in-
cluding examples, is illustrative of the invention and not in
limitation thereof.
