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Description  |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention concerns image-printing or imaging, i.e. printing letters,
characters, figures (patterns) on a substrate. More specifically the
invention concerns an improved process for image-printing and certain
improved printing inks that contain particular fluorocarbon surfactants
having the CF.sub.3 (cf.sub.2).sub.3 moiety.
2. Description of the Prior Art or
The art of printing has been defined as the act, art, or practice of
impressing letters, characters, of figures (patterns) on a substrate, and
can be termed more particularly as "imaging." Imaging demands a precision
of transfer from printing plate to substrate not required when, say, a
continuous coating is applied by printing or an application of coloring
agent is made by brush or roller.
Printing inks are composed basically of two parts, a dye or pigment
coloring agent which forms the record of print or other image pattern left
on the substrate, and a vehicle which aids in transfer of the coloring
agent. Printing inks are commonly divided into three main classes;
typographic, planographic and intaglio, corresponding to the three major
divisions of printing. Each of these three different classes of inks has
properties different from the other two.
Recently, a process has been developed for coating the inactive side of
pressure-sensitive adhesive tape with an ink containing a fluorocarbon
surfactant. The tape can be converted to rolls, where the fluoro compound
helps to keep the inactive side of the tape from sticking to the side
bearing the adhesive. This adhesive tape-coating process is quite readily
distinguished from the image-printing process of the instant invention.
The ink employed in the tape-coating process is also clearly
distinguishable from the inks of the instant invention which contain
significantly different fluorocarbon surfactants therein.
The particular printing processes that are improved according to the
teachings of this invention are as follows. The improved inks of this
invention are those that are usually employed in such printing processes
with the improvement being the incorporation therein of the particular
fluorocarbon surfactants described with particularity hereafter.
Typographic Printing
Typographic inks are used to print from raised surfaces, such as ordinary
type, line and halftone cuts. These inks usually consist of pigments
ground in a vehicle or varnish of linseed oil or of synthetic resins
dispersed in drying oils. They most often dry by oxidation of the vehicle
although heat drying is employed in some cases. Clean transfer of ink from
type to substrate and absence of ink-caused erosion of metal type and
press machinery are important in typographic ink technology.
Planographic Printing
Planographic inks are used to print from plane surfaces, as in lithographic
and offset processes. Their compositions can vary quite widely, as from
the thin ink used for newsprint to the rather thick lithographic inks.
Planographic inks are normally anhydrous and are usually water repellent.
Coloring agents for planographic inks should be relatively soft and must
be very finely divided. It is very important that all of the pigment be
wetted by the vehicle and thoroughly dispersed therein.
Intaglio Printing
Intaglio inks are used to print from engraved, or depressed, surfaces. They
include gravure and rotogravure inks and flexographic inks, all of which
are transported in and out of minute depressions in metal rolls during the
course of the printing process. Both anhydrous and water based inks are
included in this broad class.
Rotogravure inks in addition to pigments, generally employ solvent
solutions comprising a resin, a plasticizing agent, a wax and the solvent,
which may be a mixed solvent. The resin, which forms a part of the printed
matter, has several functions. It may help in causing the print to adhere
to the printed surface. It must be chosen carefully, with knowledge of the
ultimate use of the ink and of the properties of the other ink components
in mind. The resin should be soluble in the solvent component of the
vehicle. It should provide, for example, gloss, water resistance, or other
desired properties to the printed matter. It functions also to bind the
pigment and other ingredients to each other and to the substrate.
Plasticizers generally improve ink film flexibility and aid adhesion.
Waxes are added to improve scuff resistance.
In gravure printing the ink is applied to a gravure plate which holds the
ink in small indentations in the surface of the plate. When the gravure
plate is then applied to the surface to be printed, the ink is drawn to
the substrate and quickly dries thereon.
Among the problems or shortcomings faced in the gravure printing process,
are: (1) A tendency for the ink to remain in the plate instead of
transferring readily to the substrate; (2) A mottled appearance of the
printed material, indicating a discontinuity of the ink deposit; (3)
Erosive degradation of the surface of the gravure roll, changing and
distorting the printed matter derived therefrom; (4) Excessive solvent
consumption due to evaporation of liquid medium from the ink supply
fountain; and (5) Nonuniformity in quality of the printed copy due to
changes in ink viscosity and pigment concentration as solvent evaporates
and is replenished.
Many flexographic inks have a character and composition similar to those of
gravure inks. These inks are transferred during the printing process from
a roller to a printing plate by way of small cells in the roller, a
function resembling that of the small indentations in a gravure printing
plate.
SUMMARY OF THE INVENTION
This invention concerns an improvement in an image-printing process of
applying a printing ink to a substrate to be printed, the improvement
comprising applying a printing ink containing from about 0.01% to 1.0%,
based on the total weight of the ink, of a fluorocarbon surfactant
containing a fluorocarbon moiety selected from the group
CF.sub.3 (CF.sub.2).sub.3, CF.sub.3 CF(CF.sub.3)O-, and CF.sub.3
CF(CF.sub.3)CF.sub.2 -, the surfactant containing at least 25% fluorine by
weight, the balance of the fluorocarbon surfactant containing a moiety
that facilitates solubility in the printing ink. Of course, the surfactant
itself is soluble in the ink. By "moiety that facilitates solubility" is
meant that the overall surfactant solubility is attributable to this
(solubilizing) moiety.
This invention also concerns an improved printing ink comprising a coloring
agent, a liquid vehicle, and a surfactant, the improvement comprising
incorporation therein, as the surfactant, from about 0.01% to 1.0%, based
on total weight, of a fluorocarbon selected from the group
i. F(CF.sub.2).sub.n CH.sub.2 CH.sub.2 SCH.sub.2 CH.sub.2 N.sup.+ R.sub.1
R.sub.2 R.sub.3
wherein n is an integer of from 4 to 14,
R.sub.1 is an alkyl group of 1 to 4 carbon atoms,
R.sub.2 is an alkyl group of 1 to 4 carbon atoms, and
R.sub.3 is an alkyl group of 1 to 4 carbon atoms or is the covalently
bonded counterion -(CH.sub.2).sub.q SO.sub.3 .sup.- or -(CH.sub.2).sub.m
COO.sup.- wherein q is an integer of from 2 to 4, and m is an integer of
from 1 to 3, and
ii F(CF.sub.2).sub.n (CH.sub.2).sub.m O(CH.sub.2 CH.sub.2 O).sub.p H
wherein n is from 4 to 14, m is 1 to 14 and p is 1 to 20.
It should be understood that the fluorocarbon of i) above is associated
with a solubilizing counterion. The contemplated counterions are as
specifically set out (covalently bonded) or, the counterions can be other
known moieties that will readily occur to those skilled in the art such
as, for example, a chloride, iodide, acetate or similar anion.
DETAILS OF THE INVENTION
The types of printing to which the process of this invention applies and in
which the ink compositions of this invention can be employed, are as
follows.
Typographic Printing
As will be readily appreciated by those skilled in the art, the inks
employed in such printing are generally anhydrous, and comprise linseed
oil varnishes, pigment, and dryers. wax, mineral oil, resin, grease and
special varnishes are used in inks for the various kinds of presses. Ink
character and ingredients must also be adjusted for the substrate being
printed. For absorbent paper little or no drier is required. Where printed
surfaces are stacked, wax can be used to prevent the adjacent surfaces
from sticking together. The inks are made either by mixing predispersed
finely ground pigments with solvents, varnishes, etc., or by mixing dry
pigment with vehicles and grinding in ink mills. Letterpress inks
employing flushed pigments and containing a fluorocarbon surfactant as
taught herein have improved tinctorial strength and gloss.
Planographic Printing
Planographic inks are mainly used in lithographic and offset painting
processes and are greasy and water-repellent in nature. They are usually
composed of a mixture of linseed oil varnishes with a pigment, a dryer and
often additional grease and/or wax. The pigment must be very finely
divided, since a very thin volume of ink is carried by the printing
plates. For the same reason it must be very thoroughly dispersed. In
making planographic inks, the vehicle dispersant and coloring agent are
usually mixed and ground together and then the other ingredients,
including fluorocarbon surfactants are added.
A typical offset ink contains about 40% linseed oil varnish, usually a
mixture, 40% pigment and the remainder dryers. The dryers are mainly
oxidation catalysts such as cobalt or manganese soaps.
Intaglio Printing
The inks employed in gravure and flexographic printing processes have
relatively low viscosity and almost always dry by evaporation of the
solvent component. The quality of the images obtained during gravure and
flexographic printing processes is distinctly improved when a fluorocarbon
surfactant as described is included in the ink employed. The fluorocarbon
surfactant can be added to the ink at any time before it is used. It can
be used during the pigment grinding process, contributing to the ease and
speed of this operation. The effectiveness of the additive persists
through the printing process.
Among the ink solvents useful in gravure inks which are also satisfactory
solvents for many fluorosurfactants are C.sub.1 to C.sub.4 alcohols,
C.sub.6 -C.sub.8 aliphatic hydrocarbons, toluene, xylene, the acetates of
C.sub.1 to C.sub.5 alcohols, glycol ethers boiling from about 115.degree.
to 180.degree.C., C.sub.1 to C.sub.5 aliphatic ketones and cyclohexanone.
Common resins used include ethyl cellulose, nitrocellulose, polyamides,
chlorinated rubber, shellac, casein and various other natural and
synthetic resins. Plasticizers and waxes are often included in the
formulations.
Flexographic inks can have organic solvents as liquid vehicles, or, they
can employ water either as part of the vehicle or alone, without organic
solvent. The common flexographic solvents include ethanol, isopropanol,
n-propanol, propyl acetate, petroleum naphtha, lactol spirits and similar
low boiling organic solvents. Mixed water and organic solvent-based
flexographic inks generally employ alcohols, glycols, or glycol ethers as
solvents with water. Water-based flexographic inks usually contain ammonia
or another volatile amine to solubilize resin used in the vehicle.
Both organic and inorganic coloring agents can be used in the various types
of printing inks to afford the desired durable deposit on the substrate.
Pigment coloring agents are usually dispersed by milling, often in the
presence of the same liquid medium used in the ink. Sand milling, roller
milling and other methods can be employed to disperse and mix pigment and
resin. Carbon black, titanium dioxide, phthalocyanine blue, phthalocyanine
green, chrome yellows, and naphthol reds exemplify pigments used in inks.
Gravure inks are classified by a letter system which is universally used in
the printing trade. Originally designed to identify the solvents used, the
system now designates the general binder system also. A, B, C, D, E, T, W
and X are the common designations. The character of the various classes is
indicated in the Table.
TABLE
__________________________________________________________________________
GRAVURE INK CLASSES
Type
Resin or Binder Used
Solvents Used Applications
__________________________________________________________________________
A metallated resins, gil-
low-cost aliphatic hydro-
newspaper supplement,
sonite, and other hydro-
carbons such as hexane,
catalog preprint, and
carbon solvent resins
textile spirits, lactol
similar publication
spirits, VM&P, naphtha,
printing
mineral spirits
B ethylcellulose plus other
50% aromatic hydrocarbon
same as above except
modifying resins
solvent designed for better
50% aliphatic hydrocarbon
performance on coated
solvent stock
C nitrocellulose modified
esters, ketones usually
for printing on all
with resins and plasti-
extended with aromatic
papers, films, foils,
cizers hydrocarbon solvent di-
and paperboard includ-
luents such as toluene,
ing nitrocellulose-
xylene coated cellophane, glas-
sine, acetate, metal-
lized paper, etc.
D polyamides usually a 50/50 blend of
printing on foil, paper,
alcohol and aliphatic or
boards, polymer-coated
aromatic hydrocarbon
cellophane, polyethylene,
solvent polyester, and other
specialty films. Also for
hard, tough, glossy, over-
lacquer application
E nitrocellulose or ethyl-
ethanol or other alcohols
dye inks and pigmented
cellulose plus alcohol-
plus ester solvents such
inks for stocks des-
soluble resin modifiers
as ethyl acetate
cribed under type C
and plasticizers
T chlorinated rubber plus
usually aromatic hydro-
for nitrocellulose-
other modifying resins
carbon solvent such as
coated cellophane, foil,
and plasticizers
toluene or xylene
paper and board for
labels, wrappers, and
cartons; also glossy
overlacquers
W natural or synthetic resins
water plus alcohols when
for absorbent stocks
such as shellac, casein,
required; ammonia or other
such as liner board,
maleated resins, etc. wallpaper, gift wrap,
laminating inks, board
to be waxed, etc.
X any other nonrecognized
alkali used also for solu-
all other miscellaneous
type required bilization of binder
applications
__________________________________________________________________________
A typical gravure ink can contain about 25% resin, 5% plasticizer, 20%
pigment, 50% solvent and a small amount (0.5%) wax. The inks can be
prepared by mixing the ingredients in a mixer, then milling the
composition to ensure the proper degree of fineness. The pigment can be
purchased in a fine state or premilled to a fine state of division before
it is added to the ink composition. Commonly, inks are prepared in
concentrate form and diluted to the desired viscosity with solvent at
point of use.
Fluorocarbon surfactants can be added to the ink at any point during its
preparation. It is convenient, however, to add the fluorocarbon
surfactants when the ink is prepared for use, where the amount used in
relation to the other ink ingredients can be accurately determined.
Fluorocarbon Surfactants
Fluorocarbon surfactants that are useful in the process of this invention
can be either water-soluble or organic-soluble, and some have appreciable
solubility in both water and organic solvents. They can be used,
therefore, in both aqueous and nonaqueous systems. A fluorocarbon
surfactant is broadly defined as a molecule, one end (moiety) of which is
a solubilizing functional group while the other end (moiety) consists of a
perfluorocarbon group containing a minimum of three carbon atoms and
terminated by a -CF.sub.3 group.
Many fluorocarbon surfactants have been disclosed in the prior art
including representatives of anionic, cationic, amphoteric and nonionic
classes. While the broad definition given above requires only a
perfluorinated moiety and a solubilizing moiety, many fluorocarbon
surfactants contain an intervening segment which can contribute to aqueous
or nonaqueous solubility or may lend other desirable properties to the
compounds. Thus, C.sub.7 F.sub.15 COOH and C.sub.8 F.sub.17 SO.sub.3 H are
surfactants under the definition and so also are C.sub.7 F.sub.15 CH.sub.2
CH.sub.2 COOH and C.sub.8 F.sub.17 SO.sub.2 N(CH.sub.3)CH.sub.2 COOH.
Other intervening segments can consist of a sulfur or oxygen atom. The
fluorinated segment of the fluorocarbon surfactant will generally contain
from 3 to 14 carbon atoms. The expression R.sub.f in the following
formulas represents a perfluorinated alkyl of 4 to 14 carbon atoms. The
solubilizing part of the molecule can be an anion or a cation or can be
nonionic, for example, a hydroxyl or ether group. Where it exists, the
intervening segment may vary from 1 to about 16 atoms, most of which will
normally be carbon atoms. Following are given some examples of known
fluorocarbon surfactants preparable by known means.
R.sub.f COOH, R.sub.f SO.sub.3 H, R.sub.f CONH(CH.sub.2).sub.n
N(CH.sub.3).sub.2.HX where n is 2 to 6, and X is halogen;
[R.sub.f SO.sub.2 N(R)R'O].sub.m.sup.0 PX.sub.3.sub.-m where R is hydrogen
or alkyl of 1 to 12 carbons, R' is an alkylene bridging group of 2 to 12
carbons, m is an integer of 1 to 3 and X is chlorine, hydroxyl, amino,
alkoxy or aralkoxy;
R.sub.f SO.sub.2 N(R')RCOOH where R is an alkylene bridging group of 1 to
18 carbon atoms and R' is a hydrogen atom or an alkyl group of 1 to 6
carbons;
R.sub.f SO.sub.2 N(R.sub.1)-R.sub.2 CH.sub.2 OCH.sub.2 X where R.sub.1 is H
or a 1 to 6 carbon alkyl group, R.sub.2 is a 1 to 12 carbon alkylene group
and X is Cl or Br, and also quaternary ammonium salts of these compounds,
R.sub.f SO.sub.2 N(R.sub.1)-R.sub.2 CH.sub.2 OCH.sub.2 Q.sup.+X.sup.- where
Q is trialkylamino of up to 36 carbons, dialkylamino of up to 8 carbons,
pyridino, picolino, lutidino or quinilino, and R.sub.1 and R.sub.2 are as
in the preceding example;
R.sub.f CH.sub.2 CH.sub.2 SCH.sub.2 CH.sub.2 CO.sub.2 Li;
##EQU1##
CF.sub.3 CF(CF.sub.3)O(CF.sub.2).sub.x (CH.sub.2).sub.y OCH.sub.2
Q.sup.+A.sup.-, where x and y are integers of 1 to 20, Q is a positively
charged residue of a nitrogen-containing quaternizing agent, and A is an
accompanying anionic moiety;
R.sub.f -R.sub.1 CONHCH.sub.2 Q.sup.+X.sup.- where R.sub.1 is
-(CH.sub.2).sub.n -or -CH.sub.2 CHCl(CH.sub.2).sub.m -where n is 3 to 12,
m is 1 to 10, X is Cl or Br and Q is as defined immediately above;
R.sub.f SO.sub.2 NR.sub.1 (CH.sub.2).sub.m CONHCH.sub.2 Q.sup.+X.sup.-
where R.sub.1 is H or a 1 to 6 carbon alkyl, m is 2 to 12, X is Cl or Br
and Q is trialkylamino of 3 to 36 carbons, tricycloalkylamino of about 18
carbons, arylamino of about 8 carbons, aralkylamino of about 8 carbons,
pyridino, picolino, lutidino or quinilino;
R.sub.f SO.sub.2 NH(CH.sub.2).sub.n NR.sub.1 R.sub.2 and quaternaries
therefrom where n is 2 to 6 and R.sub.1 and R.sub.2 are C.sub.1 to 6 alkyl
groups;
R.sub.f CONH(CH.sub.2).sub.n N.sup.+R.sub.2 (R.sub.1)(R.sub.3)A.sup.- where
n is 2 to 6, A is an anion, R.sub.1 and R.sub.2 are C.sub.1 to 6 alkyl
groups and R.sub.3 is a C.sub.1-12 oleophilic hydrocarbon group;
[R.sub.f CH.sub.2 CH.sub.2 NR'R"R'"].sup.+X.sup.- where X is a solubilizing
anion, R' is alkyl of 1 to 8 carbons, and R" and R'" are alkyl of 1 to 8
carbons, cycloalkyl of 5 to 10 carbons; alkenyl of 3 to 8 carbons or
cycloalkenyl of 4 to 9 carbons;
R.sub.f ROCH.sub.2 Q.sup.+X.sup.- where Q is a tertiary nitrogenous
residue, X is Cl or Br and R is -CH.sub.2 -CHCl-(CH.sub.2).sub.n or
-(CH.sub.2).sub.m -where n is 1 to 10 and m is 3 to 12;
[R.sub.f CON(R)-R'-O].sub.y PO(OH).sub.3-y where R is H or alkyl of 1 to 6
carbons, R' is alkylene of 2 to 12 carbons and y is an average number of
1.5 to 2.5;
[F(CF.sub.2).sub.n CH.sub.2 CH.sub.2 O].sub.m P(O)(ONH.sub.4).sub.3-m where
n is a mixture of even integers from 4 to 14 and m is 1 or 2;
[R.sub.f CH.sub.2 O].sub.y PO(OH).sub.3-y where y is 1 or 2;
##EQU2##
where R.sub.2 and R.sub.3 are 1 to 3 carbon alkyl and p and q can be 1 to
9;
##EQU3##
where n is 1 to 10, m is 2 to 6, R' and R" are 1 to 6 carbon alkyl, and
R'" is H, an alkyl or aralkyl group and X is an anion;
R.sub.f (CH.sub.2).sub.n O(CH.sub.2).sub.m COOH where n is 2 to 14 and m is
2 to 5;
##EQU4##
where R is H or lower alkyl (1 to 6 carbon), m is 2 or 3, R' is H or
CH.sub.3, n is 2 to 20, and R" is H, CH.sub.3 or C.sub.2 H.sub.5.
The preferred fluorocarbon surfactants are not included in the list of
known surfactants set out above. They are derived from the fluoroalcohol
F(CF.sub.2).sub.n CH.sub.2 CH.sub.2 OH where n is an integer of 4 to 14,
and have the formula
F(CF.sub.2).sub.n (CH.sub.2).sub.m O(CH.sub.2 CH.sub.2 O).sub.p H where n
is from 4 to 14, m is 1 to 14 and p is 1 to 20. Of this group the most
preferred is the composition where n is a mixture of even integers from 4
to 14 and at least 60% of the n's are 4 and 6, m is 2, and p is an average
number from 9 to 12.
These preferred fluorocarbon surfactants possess both aqueous and organic
solubility. They can be made by adding the desired amount of ethylene
oxide to the fluoroalcohol, F(CF.sub.2).sub.n CH.sub.2 CH.sub.2 OH, at
70.degree. to 75.degree.C. using a small amount of boron trifluoride as
catalyst. Preparation of the fluoroalcohol is known. Addition of about
0.2% to 0.4% of one of these nonionic fluorocarbon surfactants to a
gravure ink provides excellent printing results. See Example 1.
These benefits are also achieved by employing inks having the second
preferred class of fluorocarbon surfactants: compounds containing a
solubilizing counterion either covalently bonded as a part of, or
associated with an ion of the formula
F(CF.sub.2).sub.n CH.sub.2 CH.sub.2 SCH.sub.2 CH.sub.2 N.sup.+R.sub.1
R.sub.2 R.sub.3
wherein n is an integer of from 4 to 14,
R.sub.1 is an alkyl group of 1 to 4 carbon atoms,
R.sub.2 is an alkyl group of 1 to 4 carbon atoms, and
R.sub.3 is an alkyl group of 1 to 4 carbon atoms or is the covalently
bonded counterion
-(CH.sub.2).sub.q SO.sub.3 .sup.- or -(CH.sub.2).sub.m COO.sup.- wherein
q is an integer of from 2 to 4, and
m is an integer of from 1 to 3.
Such surfactants are made generally by the procedures of Preparations 3 and
5 wherein the making of representative members of the group is explained
in detail.
Preparations 1 to 5 describe preparations of representative fluorocarbon
surfactants that are useful in the process of this invention. Preparations
1, 3 and 5 are fluorocarbon surfactants employed in the improved printing
ink formulations of this invention.
The Examples following the Preparations are meant to illustrate the
invention. Therein, the amounts of fluorocarbon surfactants are described
on the basis of 100% pure material. Of course, diluted amounts can be
added to achieve the desired concentrations.
Preparation 1
A mixture of fluoroalcohol C.sub.n F.sub.2n.sub.+1 CH.sub.2 CH.sub.2 OH
indicated by molecular weight determination to have an average composition
represented by C.sub.7 F.sub.15 CH.sub.2 CH.sub.2 OH was prepared
(according to U.S. Pat. No. 3,283,012) from a mixture of perfluoroalkyl
iodides. The perfluoroalkyl iodides comprised a mixture of C.sub.4,
C.sub.6, C.sub.8, C.sub.10, C.sub.12 and C.sub.14 perfluoroalkyl iodides.
Then, 380 Grams of the fluoroalcohol was placed in a 4-neck reaction flask
equipped with an agitator, thermometer, gas inlet tube and a condenser
cooled with a dry ice-acetone mixture. The reaction flask was swept with
dry nitrogen. The contents of the flask was then heated to 65.degree. to
90.degree.C. and boron trifluoride (0.62 ml) was added to the
fluoroalcohol. Ethylene oxide gas was then introduced into the liquid
fluoroalcohol via a gas inlet tube, maintaining the temperature at
65.degree. to 90.degree.C. After 10 hours, the total weight gain due to
ethylene oxide was greater than 350 g.
The contents of the flask was then cooled to room temperature and
transferred to distillation equipment. It was then heated to a temperature
of 65.degree. to 70.degree.C. at 35-40 mm pressure in order to remove any
unreacted ethylene oxide or 1,4-dioxane which may have formed from the
ethylene oxide. The final net increase in weight of the remaining product
was 350 g. which corresponded to an average of 10.6 units of ethylene
oxide added per mole of the fluoroalcohol. Analysis of the fluorocarbon
surfactant product by nuclear magnetic resonance confirmed that the
product obtained was the ethylene oxide addition product of the
fluoroalcohol represented by the formula C.sub.n F.sub.2n.sub.+1 CH.sub.2
CH.sub.2 O(CH.sub.2 CH.sub.2 O).sub.x H where n has an average value of
about 7 and x has an average value of about 10.6.
Preparation 2
Into a suitable vessel was charged 12.0 parts of F(CF.sub.2).sub.n CH.sub.2
CH.sub.2 OH where n is a mixture of even integers from 4 to 14. The vessel
was blanketed with nitrogen to exclude air, and the charge was heated to
60.degree.C. Then 1.80 parts of phosphoric anhydride was sifted gradually
into the charge over a period of about 45 minutes, while keeping the
temperature below 65.degree.C. When all of the phosphoric anhydride had
been added, the charge was heated and stirred at 70.degree..+-.5.degree.C.
for 20 hours. It was then cooled to 65.degree.C. and 7.6 parts of
isopropyl alcohol added.
After stirring for an hour at 55.degree. to 60.degree.C., 10.4 parts of
water was added and the temperature adjusted again to 55.degree. to
60.degree.C. Then, 2.0 parts of 30% ammonium hydroxide was added
gradually, keeping the temperature below 65.degree.C. Sufficient ammonium
hydroxide was added to make the charge alkaline, showing an orange spot on
Brilliant Yellow test papers. The charge was held at 50.degree. to
55.degree.C. for another hour, then cooled to 30.degree.C. and sampled to
determine % solids content. The strength was adjusted to 35% solids by
adding the required amount of water, and the product was ready to use. It
is a 35% solution of the fluorocarbon surfactant, [F(CF.sub.2).sub.n
CH.sub.2 CH.sub.2 O].sub.m PO(ONH.sub.4).sub.3-m, where n is a mixture of
even integers from 4 to 14 and m is 1 or 2, averaging about 11/2 .
Preparation 3
A solution was prepared of 16 parts of sodium hydroxide in 104.6 parts of
95% ethyl alcohol, and to it was added a solution of 29.2 parts of
2-dimethylaminoethanethiol hydrochloride in 60.2 parts of 95% ethyl
alcohol with stirring over a 10 minute period. The temperature of the
mixture rose to 50.degree.C. A precipitate formed as the solutions were
mixed. The mixture was heated to reflux temperature for about 20 minutes,
then cooled to room temperature. A sample turned Clayton Yellow test paper
orange, indicating a pH of 11-12.
To the prepared mixture was added 105.6 parts of F(CF.sub.2).sub.n CH.sub.2
CH.sub.2 I where n is an even integer of from 4 to 14, and the C.sub.4
component comprises less than 5%, the C.sub.6 component comprises about
55-57%, the C.sub.8 component about 27%, the C.sub.10 component about 9%
and C.sub.12 and C.sub.14 components together about 2.5%. Addition was
made over 5 minutes, the temperature rising from 25.degree.C. to
32.degree.C. The charge was then heated to boiling and refluxed under a
condenser for 15 hours, then cooled to room temperature and filtered. The
liquid filtrate turned phenolphthalein test papers barely pink.
Next, 250 parts of water was added plus sufficient 30% aqueous sodium
hydroxide solution to give a faint positive test on Clayton Yellow test
paper. After stirring 15 minutes, the charge was allowed to stand until
the aqueous and organic layers separated. The organic layer was removed
and washed two times, each time with 100 parts of water, then dried at
50.degree.C. and 1 millimeter of mercury pressure, absolute, to give 82
parts of amber colored liquid product of the formula, F(CF.sub.2).sub.n
CH.sub.2 CH.sub.2 SCH.sub.2 -CH.sub.2 N(CH.sub.3).sub.2.
In a suitable reactor 5.05 parts of the product was dissolved in 120 parts
of absolute ethanol, and 0.95 part of chloroacetic acid was added to the
solution. The charge was stirred and heated to reflux under a condenser,
and 0.4 part of sodium hydroxide was added in the form of 5% ethanol
solution. The mixture was heated at reflux overnight. After cooling to
room temperature and filtering to remove sodium chloride, the filtrate was
evaporated to dryness, yielding 5.5 parts of the fluorocarbon surfactant,
F(CF.sub.2).sub.n CH.sub.2 CH.sub.2 SCH.sub.2 CH.sub.2
N.sup.+(CH.sub.3).sub.2 CH.sub.2 COO.sup.-.
Preparation 4
A vessel was charged with 5.50 parts of methanol and 1.06 parts of
3-mercaptopropionic acid. With nitrogen atmosphere maintained over the
reaction mixture to exclude air, 1.25 parts of potassium hydroxide flakes
was added and the charge held at 50.degree. to 55.degree.C. for 1 hour
with good agitation. After cooling to below 40.degree.C., 5.26 parts of
F(CF.sub.2).sub.n CH.sub.2 CH.sub.2 I as used in Preparation 3 was added
over a one-hour period. The charge was heated to a gentle reflux at
65.degree. to 70.degree.C. and held at that temperature for 18 hours.
After cooling to about 50.degree.C., 10.0 parts of water was added, and
the charge made acid by adding 0.3 part of HCl in the form of 30% aqueous
hydrochloric acid. The charge was then allowed to separate into two
layers.
The top layer contained F(CF.sub.2).sub.n CH.sub.2 CH.sub.2 SCH.sub.2
CH.sub.2 COOH, which was mixed with 90% of its weight of 50% aqueous
isopropyl alcohol solution and heated to 45.degree. to 50.degree.C.
Sufficient lithium hydroxide monohydrate was added slowly to bring the pH
to 7.5, about 0.2 part being required. Solids content was adjusted to 50%
by adding water to give a 50% aqueous solution of the fluorocarbon
surfactant, F(CF.sub.2).sub.n CH.sub.2 CH.sub.2 SCH.sub.2 CH.sub.2 COOLi,
where n is 4 to 14.
Preparation 5
In a suitable vessel 4.0 parts of the product F(CF.sub.2).sub.n CH.sub.2
CH.sub.2 SCH.sub.2 CH.sub.2 N(CH.sub.3).sub.2 as prepared in Preparation 3
was mixed with 2.5 parts of water and 1.5 parts of isopropyl alcohol.
There was then added, slowly, 1.0 part of dimethyl sulfate with the
temperature of the mass kept below 40.degree.C. by cooling. The charge was
then stirred for 12 hours at 35.degree. to 40.degree.C. It was then
neutralized to a pH of about 8 by adding 27% ammonium hydroxide. The
fluorocarbon surfactant was F(CF.sub.2).sub.n CH.sub.2 CH.sub.2 SCH.sub.2
CH.sub.2 N.sup.+(CH.sub.3).sub.3 -(CH.sub.3 OSO.sub.3 .sup.-).
EXAMPLE 1
The process of this invention was employed on a Champlain 36 inch
Rotogravure Press capable of printing in seven colors. The printing roll
had a steel base covered with 0.020 inch copper, then chrome plated. The
roll employed a 150 line screen of 38 microns depth and 10 to 15 micron
walls.
The ink used was an ink of this invention, a black, T-type ink employing,
in amounts of 0.2% and 0.4% by total weight (2runs) the fluorocarbon
surfactant of Preparation 1. The printed substrate was solid, bleached
sulfate board with a clay coating.
Comparison of printing results produced according to the process of this
invention employing the ink of this invention with results employing an
ink without a fluorocarbon surfactant, led to the following conclusions. A
slight improvement was noted when the level of fluorocarbon surfactant was
raised to 0.4% from 0.2%.
Comparative results: (1) Without fluorocarbon surfactant, from 250,000 to
300,000 impressions could be made before it was necessary (because of
inferior printed impressions) to rechrome the rolls. With 0.2%
fluorocarbon surfactant in an ink of this invention, over 500,000
satisfactory impressions were made. (2) Distinctly better print character
was attained with the fluorocarbon surfactant-containing ink. There was
much less evidence of "snowflaking" on the printed impressions. (3) The
novel ink maintained the desired viscosity for a longer time in the ink
fountain than did the untreated ink. (4) Fully inked impressions were
conferred for a longer time with the novel fluorocarbon
surfactant-containing ink and (5) Improved gloss was given to the printed
matter.
EXAMPLES 2-4
The process of this invention was employed in each of these three
experiments comprising the imageprinting of "Aqualox" 11 Black
flexographic ink, a water based composition, product of Inter-Chemical
Corp. The press used was a 6 inch Gallus-Stanford type with a 360 Anilox
transfer roll. Under carefully controlled conditions prints were made in a
pattern generated with a By-chrome Code-Controlled Screen. The "Aqualox"
11 Black ink was reduced to a 22 second No. 2 Zahn viscosity with water,
and test prints made to establish the best conditions.
A different ink formulation was employed in each of the three experiments.
The three inks were made with a fluorocarbon surfactant of Preparations 1
and 3 (of this invention) and Preparation 2 (not of this invention) at
concentrations of 0.15% to 0.2%. Print quality was good, with the printed
lines well defined and with little smudging when the process of this
invention was employed.
EXAMPLES 5-7
Tests were performed on a gravure proofing press using a C type gravure ink
diluted to a 30 second No. 2 Zahn cup viscosity with solvent containing
equal parts by weight of ethyl alcohol, ethyl acetate and cellosolve.
Conditions were established so that a good clear print was obtained, then
prints were made with this same nonaqueous ink containing the fluorocarbon
surfactants of Preparations 1,2 and 3.
The addition of 0.2% of the fluorocarbon surfactant of Preparation 1 and
0.16% of the fluorocarbon surfactant of Preparation 3 produced two inks of
this invention that were found to significantly reduce the degree of
pinholing (failure of printed dots to appear) when compared to an ink
employing 0.14% of the fluorocarbon surfactant of Preparation 2.
EXAMPLE 8
This Example illustrates the improved utilization of pigment by an ink of
this invention.
The pigment used was AAA Benzidine Yellow, a well-known material which is
Pigment Yellow 12 in the Colour Index and has Colour Index No. 21090. It
is prepared by diazotizing 3,3'-dichlorobenzidine and coupling to 2 mols
of acetoacetanilide per mol of diazonium salt. The pigment was used in the
form of an 18% solids aqueous filter cake.
For each batch, a Baker Perkins jacketed, sigma blade mixer was charged
with 1,360 parts of the 18% filter cake and 600 parts of heat set vehicle
prepared by mixing 360 parts of "Pentalyn" K Resin (Hercules Inc.) and 240
parts of Magie 470 oil (petroleum fraction of about 470.degree.F. boiling
point). The batch was mixed until color was transferred to the oil phase,
then the water was decanted from the oil and color. Another 660 parts of
filter cake was added and the process repeated until all color was in the
oil phase. A third charge of 660 parts of press cake was added and the
process repeated again. Finally 20 parts of oleic acid was added and mixed
thoroughly with the oil and color.
At this point, the experimental condition was established. One batch of
color was processed without any surfactant except the oleic acid. To a
second batch, there was added 8 parts of the fluorocarbon surfactant of
Preparation 1, with 10 minutes additional mixing. Each batch was then
finished in exactly the same way. For each batch, the mixer was closed and
residual water removed by heating at 140.degree.F. under 25 to 28 inches
of vacuum (gauge). The water was removed in about 2 hours.
The batch without fluorocarbon surfactant was then reduced by adding an
additional 650 parts of the heat set vehicle (60% "Pentalyn" K resin and
40% Magie 470 oil) and another 240 parts of Magie 470 oil. This prepared
ink provided a standard color, and had the composition:
24.5% pigment
62.5% vehicle
1.0% oleic acid
12.0% added Magie 470 oil
The batch containing the fluorocarbon surfactant was reduced carefully to
the same strength as the standard batch, using vehicle and 470 oil in the
same proportion used for the standard, 650/240. Standard strength in the
ink of this invention was achieved at a composition:
22.5% pigment
63.8% vehicle
1.0% oleic acid
12.3% added Magie 470 oil
0.47% fluorocarbon surfactant
Thus, the same strength was achieved with only 91.8% as much pigment in the
ink of this invention,
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