U.S. patent application number 10/117910 was filed with the patent office on 2003-10-09 for self-dampening ink compositions and method for lithographic printing using the same.
Invention is credited to Durand, Richard JR., Lee, Christian John, Wasilewski, Olgierd.
Application Number | 20030190557 10/117910 |
Document ID | / |
Family ID | 28674310 |
Filed Date | 2003-10-09 |
United States Patent
Application |
20030190557 |
Kind Code |
A1 |
Lee, Christian John ; et
al. |
October 9, 2003 |
Self-dampening ink compositions and method for lithographic
printing using the same
Abstract
A self-dampening ink composition and methods for lithographic
printing using a single fluid lithographic ink are provided in the
invention in which the composition comprises glycerol in an amount
greater than 0 to about 10 percent by weight, a nonionic surfactant
with an HLB value of about 8 to about 20 in an amount from about
0.25 to about 2 percent by weight, and water in an amount of about
20 to about 50 percent by weight.
Inventors: |
Lee, Christian John;
(Parsippany, NJ) ; Wasilewski, Olgierd; (Naples,
FL) ; Durand, Richard JR.; (Woodridge, NJ) |
Correspondence
Address: |
Sidney Persley, Esq.
Sun Chemical Corporation
222 Bridge Plaza South
Fort Lee
NJ
07024
US
|
Family ID: |
28674310 |
Appl. No.: |
10/117910 |
Filed: |
April 8, 2002 |
Current U.S.
Class: |
430/331 ;
101/130; 106/31.13 |
Current CPC
Class: |
C09D 11/033 20130101;
B41N 3/08 20130101; B41M 1/06 20130101 |
Class at
Publication: |
430/331 ;
101/130; 106/31.13 |
International
Class: |
B41F 007/00; C09D
011/00 |
Claims
What is claimed is:
1. A self-dampening single fluid printing ink composition,
comprising: (a) glycerol; (b) a nonionic surfactant having a
hydrophilic/lipophilic balance of about 8 to about 20; and (c)
water.
2. The self-dampening single fluid printing ink composition
according to claim 1, wherein the amount of the glycerol present is
up to about 10 percent by weight.
3. The self-dampening single fluid printing ink composition
according to claim 1, wherein the amount of the glycerol present is
up to about 6 percent by weight.
4. The self-dampening single fluid printing ink composition
according to claim 3, wherein the amount of the gycerol is from
about 1 percent to about 3 percent by weight.
5. The self-dampening single fluid printing ink composition
according to claim 1, wherein the amount of the nonionic surfactant
is from about 0.25 to about 2 percent by weight.
6. The self-dampening single fluid printing ink composition
according to claim 1, wherein the amount of the water is from about
20 percent to about 50 percent by weight.
7. The self-dampening single fluid printing ink composition
according to claim 1, wherein the nonionic surfactant is selected
from the group consisting of silicone-derived surfactants, alkyl
phenols and polyethylene oxide derivatives thereof, alkyl amines
and polyethylene oxide derivatives thereof, fatty acid amides and
polyethylene oxide derivatives thereof, block copolymers of
propylene oxide and ethylene oxide, fatty acid esters,
polyglycosides, polypropylene glycol, oils and fats.
8. The self-dampening single fluid printing ink composition
according to claim 1, wherein the nonionic surfactant is an alkyl
phenol polyethylene oxide, a polyglycoside or combinations
thereof.
9. The self-dampening single fluid printing ink composition
according to claim 1, further comprising mineral oil.
10. The self-dampening single fluid printing ink composition
according to claim 9, wherein the mineral oil is present in an
amount of 20 percent to about 50 percent by weight based on the
total weight of the printing composition.
11. The self-dampening single fluid printing ink composition
according to claim 1, further comprising a colorant.
12. The self-dampening single fluid printing ink composition
according to claim 11, wherein the colorant is a carbon black
present in an amount of about 1 to about 20 percent by weight based
on the total weight of the printing ink composition.
13. The self-dampening single fluid printing ink composition
according to claim 1, further comprising a binder resin.
14. The self-dampening single fluid printing ink composition
according to claim 13, wherein the binder resin is present in an
amount of about 2 to about 10 weight percent based on the total
weight of the printing ink composition.
15. A method for lithographic printing comprising using a
self-dampening lithographic ink composition comprising a glycerol;
a nonionic surfactant having a hydrophilic/lipophilic balance of
about 8 to about 20; and water.
16. The method of claim 15 wherein the self-dampening printing ink
composition comprises glycerol in an amount of up to about 10
percent by weight; a nonionic surfactant having a
hydrophilic/lipophilic balance of about 8 to about 20 in an amount
of about 0.25 percent by weight to about 2 percent by weight; and
water in an amount of about 20 to about 50 percent by weight,
wherein the weight percentages are based on a total weight of the
printing ink composition.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to the field of printing ink
compositions. More particularly, it relates to single fluid
lithographic printing ink compositions for use in lithographic
printing processes. Use of single fluid lithographic ink
compositions eliminates the need for separate application of water
or other dampening solutions to be used in the printing
process.
BACKGROUND OF THE INVENTION
Description of the Related Art
[0002] Lithography is a printing process that relies on the
chemical distinction between image and non-image areas on a
printing plate rather than physical relief differentiation. Such
plates are referred to as planographic since the image and
non-image areas are in the same plane. The plates are constructed
so that, with proper treatment, the image areas are hydrophobic and
oleophilic in order to be receptive to inks. The non-image areas
are hydrophilic and water receptive. Typically, in the printing
process, using prior art printing systems in which a dampening
solution and an ink-containing solution are used, the surface of
the lithographic plates is contacted with dampening rollers to
transfer the dampening solution, such as water or an aqueous
fountain solution, prior to contacting the plates with an
ink-containing solution. The dampening solution spreads on the
non-image area of the lithographic plate, but is unable to form a
continuous layer on the image area of the plate. When subsequently
contacted with an ink-containing solution, the aqueous layer on the
non-image area of the plate inhibits the surface from accepting the
ink, while the image areas remain free to accept the ink. With the
exception of driographic plates (waterless plates) lithographic
plates require a continuous supply of dampening solution to
activate and maintain the distinction between ink-accepting image
areas and ink-repelling non-image areas. Despite the differences in
the hydrophobic/oleophilic nature of the image and non-image areas,
in the absence of dampening solution, the ink-containing solution
typically will wet both the image and non-image areas.
[0003] The use of a single fluid lithographic ink, e.g., an
emulsion of lithographic inks in water, in lithographic printing
processes is desirable to avoid problems encountered using
dampening solutions. The need for suitable single fluid inks has
been recognized for some time, since it would simplify the
lithographic process, and potentially lithographic printing press
design. However, development of useful single fluid lithographic
inks has been difficult, including the problem of maintaining a
clean non-image area accommodated by the single ink to water levels
in the formulated printing emulsion. The problem is associated with
the dependence of ink to water phase ratios on the image to
non-image coverage area required. One such solution is the
combination of a dampening solution with available lithographic
inks. However, in general, methods of preparing an emulsion ink
involving the addition of a dampening solution to available
lithographic inks have been unsuitable because of the variable
stability characteristics of such inks.
[0004] In order for a single fluid lithographic ink to be useful,
it must be formulated so that the hydrophilic phase breaks out of
the ink to maintain clean non-image areas, regardless of the degree
of ink coverage area. This need for the emulsion to separate must
be balanced against the requirement that sufficient stability in
the ink exists to prevent the two phases from separating at any
time prior to reaching the printing plate. Incompatibility will
lead to distribution and transfer problems. Excessive stability
will yield flow problems and hinder the release of the water phase
to the plate. Acceptable emulsions, in order to have the desirable
rheological and stability properties requires a balance of
interfacial chemistry, however, the volumes of water which should
be used (typically about 35-50% by volume), are beyond the
interfacial capacities of traditional lithograhic inks.
[0005] Other attempts to avoid traditional lithographic inks and
formulate a single fluid ink have been made. Some fluids use
polyhydroxy-functional compounds and mercury salts, with
lithographic plate treatments, however, such processes are very
complex and undesirable from an operating standpoint due to use of
toxic salts.
[0006] A further attempt to formulate a single fluid lithographic
ink is found in U.S. Pat. No. 4,918,517. This ink emulsion is
formed by combining an ink varnish with phosphoric acid and a
polyol. A coloring agent is then provided to create an ink varnish
resinous phase or ink vehicle. An aqueous solution having polyols
is added thereby forming an emulsion, and fuel oil is blended into
the emulsion as a non-aqueous diluent and stabilizer.
[0007] A single-fluid lithographic ink in the form of an ink
composite has also been proposed, which includes a hydrophobic
phase, including a vinyl resin having carboxyl functionality and a
polyol phase in U.S. Pat. No. 6,140,392. U.S. Pat. No. 6,200,372
includes a formulation having a macromolecular resin binder, a
rosin salt resin, an aqueous emulsion polymer, a pigment, a
water-dispersible, soy bean-based polymer and a hydroxyethylene
urea re-wetting agent.
[0008] In spite of these attempts, there is still a need in the art
for a single fluid ink composition which demonstrates stability
when subject to shear stress, but which breaks out into the ink and
aqueous phase when appropriate. Further, it would be desirable to
have such an ink which includes water that can break out when
necessary or be re-emulsified with ease.
SUMMARY OF THE INVENTION
[0009] The present invention relates to a self-dampening ink
composition comprising: (a) glycerol in an amount greater than 0
percent to about 10 percent by weight based on the total weight of
the composition; (b) a nonionic surfactant having a
hydrophilic/lipophilic balance of about 8 to about 20 in an amount
of about 0.25 to about 2 percent by weight based on the total
weight of the composition; and (c) water in an amount of about 20
to about 50 percent by weight based on the total weight of the
composition, wherein the ink composition is capable of being used
as a single fluid lithographic ink.
[0010] A method for lithographic printing is also provided which
comprises directly wetting image and non-image areas of a
lithographic plate with a self-dampening lithographic ink
composition, wherein the composition comprises glycerol in an
amount greater than 0 percent to about 10 percent by weight; a
nonionic surfactant having a hydrophilic/lipophilic balance (HLB)
of about 8 to about 20 in an amount of about 0.25 percent by weight
to about 2 percent by weight; and water in an amount of about 20 to
about 50 percent by weight, wherein the weight percentages are
based on a total weight of the composition.
[0011] Further provided in a method of lithographic printing using
a single fluid lithographic ink, is the improvement which comprises
using a self-dampening ink composition comprising glycerol in an
amount greater than 0 percent to about 10 percent by weight; a
nonionic surfactant having a hydrophilic/lipophilic balance of
about 8 and about 20 in an amount of about 0.25 percent by weight
to about 2 percent by weight; and water in an amount of about 20 to
about 50 percent by weight, wherein the weight percentages are
based on a total weight of the composition.
DETAILED DESCRIPTION OF THE INVENTION
[0012] The present invention includes a self-dampening ink
composition and an improved lithographic printing method which
includes using the self-dampening ink composition of the present
invention. The composition of the present invention generally
includes glycerol, nonionic surfactants with a
hydrophilic/lipophilic balance (HLB) value of about 8 to about 20,
and water. The composition of the invention is self-dampening in
that there is no need for use of additional water or dampening
solutions when applying the ink compositions in lithographic
printing methods. As used herein "single fluid" refers to a
self-dampening ink for lithographic printing which is used alone,
without dampening solutions or a separate source of water, to
directly wet a lithographic plate in the hydrophilic areas while
also wetting the hydrophobic areas.
[0013] For single fluid printing, the hydrophilic phase is
incorporated into a hydrophobic phase (ink) and directly used for
printing as described above. The present invention meets the
requirements of a single fluid lithographic, self-dampening ink in
that the hydrophilic phase breaks out of the ink in order to
maintain clean non-image areas, regardless of ink coverage.
Further, the need for the emulsion to break is balanced by the
requirement that sufficient stability exists to prevent the two
phases from separating at any time prior to reaching the printing
plate even when subjected to shear in the printing operation. The
stability does not hinder distribution and transfer or prevent an
equilibrium from being obtained on the roller train. The ability of
the phases to break out when appropriate prevents flow problems and
does not hinder the release of the water phase to the plate. Thus,
the proper emulsion rheology and stability for acceptable printing
via the single fluid concept requiring a proper balance of
interfacial chemistry is achieved by the present invention.
[0014] The potential effectiveness of the ink composition in use in
a lithographic press is determined using several tests developed by
applicants. The ink composition's non-image cleaning ability on a
lithographic plate is evaluated using a quick peek proofer. A quick
peek proofer is simply a rubber roller used to apply an ink film to
a surface. The test was performed by measuring a volume of ink onto
a roller and then distributing the ink on the non-image area of a
conventional lithographic plate (such as Vistar series from KPG).
The Quick Peek Proofer is available from the Thwing-Albert
Instrument Company. The lack of ink reception in the non-image area
is the positive test to assess composition using the proofer.
[0015] The stability of the emulsion and the presence of surface
water are evaluated using a slipperiness test in a glass jar. The
glass jar test was performed by placing emulsified ink into a glass
jar. A positive test resultwass obtained in that the ink could move
in the jar without ink sticking to the jar and without water
separating from the emulsion. The rheological properties of the
emulsion are evaluated using a rheometer. A Carri-Med CSL-550
rheometer was used. A flow sweep (shear stress vs. shear rate) was
carried out and the maximum stress achieved before emulsion break
was noted. Excessive stability or instabilities were noted by this
test. A positive evaluation of these tests helps to indicate that
the ink emulsion possesses the requirements for successful
operation in a lithographic printing process.
[0016] The compositions of the present invention preferably
incorporate minor amounts of glycerol which functions to help
stabilize the hydrophilic phases in the ink prior to
emulsification, as well as to help lubricate the non-image of the
printing plate during printing. The amount of glycerol utilized is
not critical, and from 0 weight percent to 10 weight percent, based
on the total weight of the composition, can be incorporated.
Preferably, glycerol is present in the composition in an amount up
to about 6 weight percent, based on the total weight of the
composition. More preferably, glycerol is present in the
composition in an amount ranging from about 1 weight percent to
about 3 weight percent, and most preferably in an amount of about 2
weight percent, based on the total weight of the composition.
[0017] Since the composition is a single fluid, self-dampening
composition, it includes water as a dampening agent/hydrophilic
phase within the formulation. Preferably, water is present in the
composition in a range from about 20 weight percent to about 50
weight percent, based on the total weight of the composition. More
preferably, water is present in the composition in an amount of
from about 35 weight percent to about 50 weight percent, based on
the total weight of the composition.
[0018] At least one non-ionic surfactant having a
hydrophilic/lipophilic balance (HLB) of about 8 to about 20 is used
in the present formulation. The presence of the non-ionic
surfactant positively affects emulsion stability by releasing
emulsified water from the emulsion efficiently. Higher HLB values
have generally been found to be most effective. The surfactants may
be in combination, but it is not necessary for them to be. It is,
however, necessary for them to affect the ink in such a way so as
to produce proper test responses indicative of the existence of a
balanced emulsion. For the non-ionic surfactants, pH is not a
factor.
[0019] It is preferred to include from about 0.25 weight percent to
about 2 weight percent, and preferably from about 0.5 weight
percent to about 1.5 weight percent, based on the total weight of
the self-dampening ink composition, of at least one non-ionic
surfactant having an HLB of from about 8 to about 20.
[0020] Suitable non-ionic surfactants are those having the desired
HLB balance and which can include C.sub.10-C.sub.20 alkylphenol
ethoxylates and polyethylene oxide derivatives of the same,
C.sub.10-C.sub.20 polyoxyethylene alkylaryl ethers,
C.sub.10-C.sub.24 fatty alchol ethoxylates, ethoxylates of alcohols
derived from lanolin, ethoxylated monoglycerides, ethoxylated
diglycerides, ethoxylated triglycerides, ethoxylated
polyoxypropylene glycol and block copolymers of propylene oxide and
ethylene oxide having a weight average molecular weight of about
2,500 to about 7,500. Other, more preferred examples of nonionic
surfactants with a HLB between about 8 and about 20 that may be
included in the ink composition of the present invention include
silicone derived surfactants such as Silwet.RTM., manufactured by
CK Witco, for example Silwet.RTM. 7657 (Witco)(HLB 13.0-17.0),
alkyl phenols and alkyl phenol polyethylene oxide derivatives such
as Igepale.RTM. CA720 and CO430, available from Sigma-Aldrich,
alkyl amines and alkyl amine polyethylene oxide derivatives, such
as Synperonic.RTM. T, available from Uniqema, fatty acids and fatty
acid polyethylene oxide derivatives such as Mazamide.RTM.,
manufactured by BASF, propylene oxide/ethylene oxide block
copolymers such as Synperonic.RTM. PE, available from Uniqema, such
synperonic monomers being comprised of propylene oxide and ethylene
oxide, for example Synperonic PE (Uniqema), fatty acid esters such
as T-Maz.RTM. 80 wherein such sorbitan derivatives include POE(20)
sorbitan monooleate (BASF)(HLB 15.0), polyglycosides such as
Glucopon.RTM., for example alkyl polyglycosides such as
Glucopon.RTM. 425 (Henkel Glucopon)(HLB 13.1), polypropylene
glycols such as Macol.RTM. P-2000 available from BASF or Macol
OP-ethoylated alcohols such as Macol.RTM. OP12 (BASF)(HLB 14.6),
and oils and fats such as Alkamul.RTM. EL-985 available from
Rhodia. Most preferred are alkyl phenol polyoxyethylene oxide
and/or polyglycosides alone or in combination.
[0021] Various other components can be included in the ink
composition of the present invention. Mineral oil, or any suitable
equivalent known or to be developed in the art, is preferably
included as an emulsification vehicle. Mineral oil is preferably
present in the formulation in an amount of about 10 weight percent
to about 90 weight percent based on the total weight of the ink
composition, more preferably from about 20 weight percent to about
50 weight percent and most preferably from about 40 weight percent
to about 50 weight percent.
[0022] Various colorants, including dyes and, more preferably,
pigments are used in the ink formulations of the present invention,
alone or in combination. A wide range of pigments may be employed
in the printing ink compositions of the present invention,
including any suitable pigment or dye typically used or to be
developed for lithographic printing. Non-limiting examples of
useful pigments include various carbon blacks, CI Pigment Yellows
12, 13 and 17; CI Pigment Reds 2, 4, 48.2, 53.1, 57:1 and 81; CI
Pigment Oranges 13 and 34; CI Pigment Black 7, CI Pigment Blues 1,
15, 15.1 and 18; CI Pigment Violets 1, 3 and 23; CI Pigment Greens
1, 2 and 7; CI Pigment Whites 6 and 18, combinations of these
various pigments and similar colorants. Preferably, the pigment
includes primarily standard ink grades of carbon black, or
completely carbon black alone or with carbon black wetting agents
such as asphaltum, pitches and bitumen. Preferably, the colorant is
present in the formulation in an amount of from about 1 weight
percent to about 30 weight percent based on the total weight of the
composition, more preferably from about 1 weight percent to about
20 weight percent, and most preferably in an amount of about 5
weight percent to about 15 weight percent.
[0023] A binder varnish can also be included in the ink composition
which includes a binder resin in an oil base for acting as a
thixotropic/rheology adjusting agent and as a further
solvent/vehicle for the oleophilic phase. All standard binder
resins are possible. Such binder resins are not critical to the
invention as the additives that provide the inventive composition
are independent of the binder resin used. Suitable binder resins
include those commercially available as Coblax.RTM. and as well as
other hydrocarbon-containing varnishes including Gilsonite resin in
Magie 470 oil and maleic anhydride-modified hydrocarbon in Magie
470 oil. Non-limiting examples of binder resins include: gilsonite,
asphaltic resins (Coblax), hydrocarbon, modified hydrocarbon,
phenolic, rosin, rosin esters, and modified rosins (phenolic,
fumaric,maleic) esters. The binder resin, if used, is present in
the formulation in an amount of about 1 weight percent to about 50
weight percent, preferably from about 2 weight percent to about 10
weight percent, based on the total weight of the ink
composition.
[0024] Moreover, conventional amounts of typical additives useful
in lithographic inks may also be included in the compositions of
the present invention, including without limitation, organoclays,
polyethylene wax, polytetrafluoroethylene wax, silicas, polyamides
and aluminum chelates, low molecular weight hydrocarbon resins, and
the like.
[0025] The invention will now be further described in accordance
with the following non-limiting example:
EXAMPLE 1
[0026] The following ink compositions A and B were formulated as
shown in Table 1 including all components in weight percentage
amounts. The compositions were prepared from a standard formulation
that except for water, surfactant and glycerol has already been
prepared by standard techniques that do not require specific mixing
procedure that is senstive to order of addition.
1 TABLE I Component Composition A Composition B Mineral Oil 47.00
47.35 (San Joaquin Refining 2000 SUS Petroleum Oil) Carbon Black
13.00 13.00 (Cabot CSX-372 (DBP value is 72)) Binder Varnish
(Coblax .RTM.) 2.00 2.00 Glycerol 2.00 2.00 Water 35.00 35.00
lgepal .RTM. CO430 -- 0.65 (alkyl phenol polyethylene oxide)
Glycopon .RTM. 425 1.0 -- (polyglycoside) Total 100.00 2100.00
[0027] The effectiveness of the compositions A and B were evaluated
by first determining the cleaning ability of the ink emulsion on a
lithographic plate using a quick peek proofer. Next, the stability
of the emulsion and surface water was evaluated using a
slipperiness test in a glass jar. Finally, the rheology of the
emulsions were measured on a rheometer. These tests indicated that
the ink emulsions would perform successfully in a lithographic
printing process based on classification as good to very good with
regard to behavior that yields good behavior on press.
[0028] The invention also includes a method for lithographic
printing which may include any acceptable lithographic printing
process such as those described or referenced in U.S. Pat. Nos.
4,981,517 and 5,372,635, incorporated herein by reference. In the
method of the invention, the image and non-image areas of a
lithographic plate are directly wetted, that is without prior use
of a dampening solution or water, with a self-dampening
lithographic ink composition. Preferably, the self-dampening ink
composition is one in accordance with the above description of the
invention in which the composition includes glycerol in an amount
greater than 0 weight percent to about 6 weight percent; a nonionic
surfactant having a hydrophilic/lipophilic balance of about 8 to
about 20 in an amount of about 0.25 weight percent to about 2
weight percent; and water in an amount of about 20 weight percent
to about 50 weight percent, with all weight percentages being based
on a total weight of the composition, and which may include any of
the additives or additional preferred components noted above.
[0029] The invention also includes an improvement for any
acceptable method of lithographic printing using a single-fluid
lithographic ink known in the art or to be developed. The
improvement includes using a self-dampening ink composition which
is preferably any of the self-dampening ink compositions according
to the invention as described above.
[0030] 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.
* * * * *