U.S. patent application number 09/901157 was filed with the patent office on 2002-04-11 for citric acid tri-alkylamide surfactants.
Invention is credited to Lassila, Kevin Rodney, Meier, Ingrid Kristine, Slone, Caroline Sassano.
Application Number | 20020041933 09/901157 |
Document ID | / |
Family ID | 24492113 |
Filed Date | 2002-04-11 |
United States Patent
Application |
20020041933 |
Kind Code |
A1 |
Slone, Caroline Sassano ; et
al. |
April 11, 2002 |
Citric acid tri-alkylamide surfactants
Abstract
This invention provides water-based compositions which are
essentially free of hydrocarbon solvents, particularly coating,
ink, fountain solution, adhesive, agricultural and electronics
cleaning compositions, manifesting reduced equilibrium and dynamic
surface tension by the incorporation of a surface tension reducing
amount of certain tri-alkylamides of citric acid of the structure 1
where R.sub.1, R.sub.2 and R.sub.3 are independently C1 to C18
alkyl groups.
Inventors: |
Slone, Caroline Sassano;
(Quakertown, PA) ; Lassila, Kevin Rodney;
(Macungie, PA) ; Meier, Ingrid Kristine; (Asbury,
NJ) |
Correspondence
Address: |
AIR PRODUCTS AND CHEMICALS, INC.
PATENT DEPARTMENT
7201 HAMILTON BOULEVARD
ALLENTOWN
PA
181951501
|
Family ID: |
24492113 |
Appl. No.: |
09/901157 |
Filed: |
July 9, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09901157 |
Jul 9, 2001 |
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09621898 |
Jul 20, 2000 |
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6306463 |
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Current U.S.
Class: |
427/384 |
Current CPC
Class: |
G03F 7/322 20130101;
A61Q 19/10 20130101; C09D 11/38 20130101; A61K 8/42 20130101; C09K
23/00 20220101; C11D 1/528 20130101; A61Q 5/02 20130101; C09D 11/03
20130101; C09D 5/027 20130101; A01N 25/30 20130101 |
Class at
Publication: |
427/384 |
International
Class: |
B05D 003/02 |
Claims
We claim:
1. In a method for applying a coating of a water-based composition
to a surface to partially or fully coat the surface and drying the
coating, the composition containing an inorganic or organic
compound and an effective amount of a surfactant for reducing the
dynamic surface tension of the composition, the improvement which
comprises employing as the surfactant a tri-alkylamide of citric
acid of the formula: 13where R.sub.1, R.sub.2 and R.sub.3 are
independently C1 to C18 alkyl groups.
2. The method of claim 1 in which the water-based composition is
selected from the group consisting of aqueous organic protective or
decorative coating, ink, adhesive, fountain solution, agricultural,
photoresist developing and electronics cleaning compositions and
the tri-alkylamide is present at 0.001 to 20 wt % of the
water-based composition.
3. The method of claim 2 in which an aqueous solution of the
tri-alkylamide of citric acid demonstrates a dynamic surface
tension of less than 50 dynes/cm at a concentration of .ltoreq.5 wt
% in water at 25.degree. C. and 20 bubbles/second according to the
maximum-bubble-pressure method.
4. The method of claim 1 in which R.sub.1, R.sub.2 and R.sub.3 are
C2 to C8 alkyl groups.
5. The method of claim 1 in which R.sub.1, R.sub.2 and R.sub.3 are
C3 to C5 alkyl groups.
6. The method of claim 1 in which R.sub.1, R.sub.2 and R.sub.3 are
the same.
7. The method of claim 6 in which R.sub.1, R.sub.2 and R.sub.3 are
a C4 alkyl group.
8. The method of claim 6 in which R.sub.1, R.sub.2 and R.sub.3 are
a C5 alkyl group.
9. The method of claim 6 in which the alkyl groups are n-butyl.
10. The method of claim 6 in which the alkyl groups are
iso-butyl.
11. An aqueous composition comprising in water an inorganic
compound which is a mineral ore or a pigment or an organic compound
which is a pigment, a polymerizable monomer, an oligomeric resin, a
polymeric resin, a detergent, a herbicide, an insecticide, a
fungicide, or a plant growth modifying agent and an effective
amount of a tri-alkylamide of citric acid for reducing the dynamic
surface tension of the composition, the tri-alkylamide of citric
acid having the formula: 14where R.sub.1, R.sub.2 and R.sub.3 are
independently C2 to C8 alkyl groups.
12. The aqueous composition of claim 11 in which an aqueous
solution of the tri-alkylamide demonstrates a dynamic surface
tension of less than 50 dynes/cm at a concentration of .ltoreq.5 wt
% in water at 25.degree. C. and 20 bubbles/second according to the
maximum-bubble-pressure method and the tartrate diester is present
at 0.01 to 10 wt % of the aqueous composition.
13. The aqueous composition of claim 12 in which R.sub.1, R.sub.2
and R.sub.3 are C3 to C5 alkyl groups.
14. The aqueous composition of claim 12 in which R.sub.1, R.sub.2
and R.sub.3 are the same.
15. The aqueous composition of claim 14 in which R.sub.1, R.sub.2
and R.sub.3 are a C4 alkyl group.
16. The aqueous composition of claim 14 in which R.sub.1, R.sub.2
and R.sub.3 are a C5 alkyl group.
17. The aqueous composition of claim 14 in which the alkyl groups
are n-butyl.
18. The aqueous composition of claim 14 in which the alkyl groups
are iso-butyl.
19. The composition of claim 11 which is an aqueous organic coating
composition comprising in an aqueous medium 30 to 80 wt % of a
coating composition which comprises the following components 0 to
50 wt % pigment dispersant, grind resin or mixtures thereof; 0 to
80 wt % coloring pigment, extender pigment, anti-corrosive pigment,
other pigment types or mixtures thereof; 5 to 99.9 wt %
water-borne, water-dispersible or water-soluble resin or mixtures
thereof; 0 to 30 wt % slip additive, antimicrobial agent,
processing aid, defoamer or mixtures thereof; 0 to 50 wt %
coalescing or other solvent; 0.01 to 10 wt % surfactant, wetting
agent, flow and leveling agents or mixtures thereof; and 0.01 to 20
wt % tri-alkylamide of citric acid.
20. The composition of claim 11 which is an aqueous ink composition
comprising in an aqueous medium 20 to 60 wt % of an ink composition
which comprises the following components 1 to 50 wt % pigment; 0 to
50 wt % pigment dispersant, grind resin or mixtures thereof; 0 to
50 wt % clay base in a resin solution vehicle; 5 to 99 wt %
water-borne, water-dispersible or water-soluble resin or mixtures
thereof; 0 to 30 wt % coalescing or other solvent; 0.01 to 10 wt %
processing aid, defoamer, solubilizing agent or mixtures thereof;
0.01 to 10 wt % surfactant, wetting agent or mixtures thereof; and
0.01 to 20 wt % tri-alkylamide of citric acid.
21. The composition of claim 11 which is an aqueous agricultural
composition comprising in an aqueous medium 0.01 to 80 wt % of an
agricultural composition which comprises the following components
0.1 to 50 wt % a herbicide, insecticide, plant growth modifying
agent or mixtures thereof; 0.01 to 10 wt % surfactant; 0 to 5 wt %
dye; 0 to 20 wt % thickener, stabilizer, co-surfactant, gel
inhibitor, defoaming agent or mixtures thereof; 0 to 25 wt %
antifreeze; and 0.01 to 50 wt % tri-alkylamide of citric acid.
22. The composition of claim 11 which is an aqueous fountain
solution composition comprising the following components 0.05 to 10
wt % film formable, water soluble macromolecule; 1 to 25 wt %
alcohol, glycol, or polyol with 2-12 carbon atoms which is water
soluble or can be made water soluble; 0.01 to 20 wt % water soluble
organic acid, inorganic acid, or a salt thereof; 30 to 70 wt %
water; and 0.01 to 5 wt % tri-alkylamide of citric acid.
23. The composition of claim 11 which is an aqueous adhesive
composition comprising in an aqueous medium 30 to 65 wt % of an
adhesive composition which comprises the following components 50 to
99 wt % polymeric resin; 0 to 50 wt % tackifier; 0 to 0.5 wt %
defoamer; and 0.5 to 2 wt % tri-alkylamide of citric acid.
24. The composition of claim 11 which is an aqueous electronics
cleaning composition comprising in an aqueous medium the following
components 0.1 to 3 wt % tetramethylammonium hydroxide; 0 to 4 wt %
phenolic compound; and 10 to 10,000 ppm tri-alkylamide of citric
acid.
Description
FIELD OF THE INVENTION
[0001] The invention relates to the use of citric acid
tri-alkylamides to reduce the surface tension in water-based
systems.
BACKGROUND OF THE INVENTION
[0002] The ability to reduce the surface tension of water is of
great importance in waterborne coatings, inks, adhesives, fountain
solutions, agricultural formulations and cleaning compositions for
electronics processes such as semiconductor manufacture because
decreased surface tension translates to enhanced substrate wetting
in actual formulations. Surface tension reduction in water-based
systems is generally achieved through the addition of surfactants.
Performance attributes resulting from the addition of surfactants
include enhanced surface coverage, fewer defects, and a more
uniform distribution. Equilibrium surface tension performance is
important when a system is at rest. However, the ability to reduce
surface tension under dynamic conditions is of great importance in
applications where high surface creation rates are utilized. Such
applications include the spraying, rolling and brushing of coatings
or agricultural formulations, or high speed gravure or ink-jet
printing. Dynamic surface tension is a fundamental quantity which
provides a measure of the ability of a surfactant to reduce surface
tension and provide wetting under high speed application
conditions.
[0003] Traditional nonionic surfactants such as alkylphenol or
alcohol ethoxylates and ethylene oxide (EO)/propylene oxide (PO)
copolymers have excellent equilibrium surface tension performance
but are generally characterized as having poor dynamic surface
tension reduction. In contrast, anionic surfactants such as sodium
dialkyl sulfosuccinates can provide good dynamic results, but are
very foamy and impart water sensitivity to the finished
coating.
[0004] In addition to the development of high-performance
surfactants, there is considerable interest in the industry in
surfactants with improved environmental characteristics.
Environmental concerns have led to an increased use of
environmentally compatible surfactants as alternatives have become
available. In addition, the use of less favorable products, such as
alkylphenol ethoxylate (APE) surfactants, has declined. This is, in
part, due to the poor environmental characteristics of APE
surfactants, such as incomplete biodegradation and a suspicion that
they may function as endocrine mimics.
[0005] The demand for high-performance, eco-friendly surfactants
has stimulated efforts in new surfactant development. From this
work a new family of surfactants, referred to as alkyl
polyglycoside (APG) surfactants, has emerged as a readily
biodegradable, environmentally-friendly alternative to conventional
surfactants. These materials, however, can be foamy and thus, are
not suitable for a variety of coating, ink, adhesive and
agricultural applications where the generation of foam is
undesirable. Thus, not only is it desirable to obtain surfactants
which exhibit excellent surface tension reducing capabilities, but
it is also desirable that these surfactants exhibit low foam under
dynamic application conditions and are environmentally
friendly.
[0006] There is a need for surfactants which exhibit good
equilibrium and dynamic surface tension properties, are
low-foaming, and would be widely accepted in the waterborne
coating, ink, adhesive, fountain solution, agricultural formulation
and electronics manufacturing industries. Moreover, since there is
substantial interest in the development of environmentally friendly
surfactants, an essential attribute would be that these new
surfactants not only possess the aforementioned desired performance
attributes but also are derived from natural, renewable
resources.
[0007] The importance of reducing equilibrium and dynamic surface
tension in applications such as coatings, inks, adhesives, fountain
solutions, agricultural formulations and electronics cleaning
compositions, e.g., aqueous developer solutions for making
semiconductor devices, is well-appreciated in the art.
[0008] Low dynamic surface tension is of great importance in the
application of waterborne coatings. In an article, Schwartz, J.
"The Importance of Low Dynamic Surface Tension in Waterborne
Coatings", Journal of Coatings Technology, September 1992, there is
a discussion of surface tension properties in waterborne coatings
and a discussion of dynamic surface tension in such coatings.
Equilibrium and dynamic surface tension were evaluated for several
surface active agents. It is pointed out that low dynamic surface
tension is an important factor in achieving superior film formation
in waterborne coatings. Dynamic coating application methods require
surfactants with low dynamic surface tensions in order to prevent
defects such as retraction, craters and foam.
[0009] Efficient application of agricultural products is also
highly dependent on the dynamic surface tension properties of the
formulation. In an article, Wirth, W.; Storp, S.; Jacobsen, W.
"Mechanisms Controlling Leaf Retention of Agricultural Spray
Solutions", Pestic. Sci. 1991, 33, 411-420, the relationship
between the dynamic surface tension of agricultural formulations
and the ability of these formulations to be retained on a leaf was
studied. These workers observed a good correlation between
retention values and dynamic surface tension, with more effective
retention of formulations exhibiting low dynamic surface
tension.
[0010] Low dynamic surface tension is also important in high-speed
printing as discussed in the article "Using Surfactants to
Formulate VOC Compliant Waterbased Inks", Medina, S. W.; Sutovich,
M. N. Am. Ink Maker 1994, 72 (2), 32-38. In this article, it is
stated that equilibrium surface tensions (ESTs) are pertinent only
to ink systems at rest. EST values, however, are not good
indicators of performance in the dynamic, high speed printing
environment under which the ink is used. Dynamic surface tension is
a more appropriate property. This dynamic measurement is an
indicator of the ability of the surfactant to migrate to a newly
created ink/substrate interface to provide wetting during high
speed printing.
[0011] Tetramethylammonium hydroxide (TMAH) is the chemical of
choice in aqueous alkaline solutions for developing photoresists
according to Microlithography, Science and Technology, edited by J.
R. Sheats and B. W. Smith, Marcel Dekker, Inc., 1998, pp 551-553.
Surfactants are added to the aqueous TMAH solutions to reduce
development time and scumming and to improve surface wetting.
[0012] U.S. Pat. No. 5,562,762 discloses an aqueous jet ink of
water, dissolved dyes and a tertiary amine having two
polyethoxylate substituents and that low dynamic surface tension is
important in ink jet printing.
[0013] Citric acid (2-hydroxy-1,2,3-propanetricarboxylic acid) is
found in nature and is a common metabolite for many plants and
animals. It is classified as GRAS (Generally Recognized As Safe) by
the U.S. Food and Drug Administration and is commonly used in
foods, pharmaceuticals, detergents, cosmetics, cleaners and
enhanced oil recovery. Citric acid is produced by the fermentation
of sugars, such as corn starch or molasses.
[0014] Anionic surfactants based on citric acid amides are
known.
[0015] JP 08302387A discloses the use of mono-amides prepared from
citric acid and C10-C20 amines as surfactants in cosmetic
formulations. These anionic surfactants are foamy and, thus, not
suited for coating applications, such as the spraying, rolling and
brushing of coatings or agricultural formulations, or high speed
gravure or ink-jet printing.
[0016] U.S. Pat. No. 3,946,074 discloses di- and tri-amides of
aliphatic polycarboxylic acids, including citric acid as growth
regulators when applied to plants as an organic or aqueous solution
or as an aqueous emulsion. The citramide,
N,N,N',N'-tetramethyl-N"-1-methyldecyl citramide, was synthesized
in Example 1.
[0017] JP06100833 discloses aqueous ink compositions containing
water soluble dyes or water dispersible pigments, a water soluble
organic solvent and a tri-carboxylic acid amide.
[0018] GB 944515 discloses citric acid amides containing as part of
the amide residue at least one residue of an alkylene diamine
carrying on one nitrogen atom a C10-C22 aliphatic hydrocarbon
residue. Citric acid amides of this type were shown to be active as
bactericides and fungicides in aqueous compositions.
[0019] JP 09286768 discloses tri-amides of citric acid containing
C8-C22 alkyl or alkylene groups, e.g., trioctyl- and
tridodecylamides of citric acid, as lubricants, releases and
dispersants for the processing of thermoplastic and thermosetting
resins and synthetic rubber. In all examples, the citramide
additive was added to non-aqueous compositions.
[0020] U.S. Pat. No. 5,776,494 discloses the use of alkylamides of
di-and/or tribasic carboxylic acids, e.g.,
2-hydroxy-1,2,3-propanetributy- lamide, as gelling agents in
pharmaceutical compositions in the form of a gel or gel stick. The
compositions are prepared using an anhydrous liquid carrier which
contains <5% water.
SUMMARY OF THE INVENTION
[0021] The invention provides water-based compositions which
contain an organic or inorganic compound, particularly aqueous
organic protective or decorative coating, ink, adhesive, fountain
solution, agricultural and electronics cleaning compositions,
having reduced equilibrium and dynamic surface tension by
incorporation of an effective amount of a tri-alkylamide of citric
acid ("citramide") of the formula: 2
[0022] where R.sub.1, R.sub.2 and R.sub.3 are independently C1 to
C18 alkyl groups. It is desirable that an aqueous solution of the
citramide demonstrates a dynamic surface tension of less than 50
dynes/cm at a concentration of .ltoreq.5 wt % in water at
25.degree. C. and 20 bubble/second according to the maximum bubble
pressure method. The maximum bubble pressure method of measuring
surface tension is described in Langmuir 1986, 2, 428-432, which is
incorporated by reference.
[0023] By "water-based", "aqueous" or "aqueous medium", we mean,
for purposes of this invention, a solvent or liquid dispersing
medium which comprises at least 90 wt %, preferably at least 95 wt
%, water. Obviously, an all water medium is also included. In
addition, it is desirable that the water-based compositions are
essentially free of hydrocarbon solvent.
[0024] Also provided is a method for lowering the equilibrium and
dynamic surface tension of such aqueous compositions by the
incorporation of these citramide compounds.
[0025] Also provided is a method for applying a coating of a
water-based inorganic or organic compound-containing composition to
a surface to partially or fully coat the surface with the
water-based composition and drying the composition to deposit a
coating, the composition containing an effective amount of a
citramide compound of the above structure for reducing the dynamic
surface tension of the water-based composition.
[0026] There are significant advantages associated with the use of
these citramides in water-based organic coatings, inks, adhesives,
fountain solutions, agricultural and electronics chemical
compositions and these advantages include:
[0027] water-borne coatings, inks, adhesives, fountain solutions,
agricultural and electronics chemical formulations which may be
applied to a variety of substrates with excellent wetting of
substrate surfaces;
[0028] a reduction in coating or printing defects such as orange
peel and flow/leveling deficiencies;
[0029] coating and ink compositions capable of high speed
application;
[0030] low-foam surfactants capable of reducing dynamic surface
tension;
[0031] low-foam surfactants which have low odor;
[0032] water-borne compositions using a surfactant derived from
natural, renewable resources, thus making such formulations
environmentally favorable; and
[0033] an ability to formulate low surface tension aqueous
electronics cleaning and processing solutions, including
photoresist developer solutions, for the semiconductor
manufacturing industry with good wetting and extremely low
foam.
[0034] Because of their excellent surfactant properties and the
ability to control foam, these materials are likely to find use in
many applications in which reduction in dynamic and equilibrium
surface tension and low foam are important. Applications in which
low foam is important include various wet-processing textile
operations, such as dyeing of fibers, fiber scouring, and kier
boiling, where low-foaming properties would be particularly
advantageous; they may also have applicability in soaps,
water-based perfumes, shampoos, detergents, cleaners, cosmetics and
food processing where their marked ability to lower surface tension
while simultaneously producing substantially no foam would be
highly desirable.
[0035] In addition, the demands of the semiconductor fabrication
industry have led to the requirement for high performance
surfactants and wetting agents for photoresist developer
formulations. As line features shrink to smaller sizes and
photoresist substrate materials become more aliphatic in nature
(i.e., lower surface energy), aqueous developer solutions
increasingly are being formulated with surface tension reducing
agents.
[0036] An additional requirement for these developers, accentuated
by the move toward larger wafer sizes, is that they exhibit low
foam. This is particularly important when the so-called spray
puddle techniques are used in applying the developer solution,
wherein the developer is sprayed over increasingly larger areas.
Even in cases where puddle or immersion techniques are used,
microbubble entrainment during spreading of the solution over the
photoresist surface can lead to defects. The materials according to
the present invention give efficient reduction of surface tension
of aqueous developer solutions and exceedingly low foam, even under
extreme conditions. Other applications in the electronics industry
using aqueous processing media would also benefit from good dynamic
wetting and low foam.
DETAILED DESCRIPTION OF THE INVENTION
[0037] This invention relates to the use of citramide compounds of
the structure 3
[0038] where R.sub.1, R.sub.2 and R.sub.3 are C1 to C18 alkyl
groups, preferably C2 to C8 and most preferably C3 to C5, for the
reduction of equilibrium and dynamic surface tension in water-based
compositions which are essentially free of aliphatic and aromatic
hydrocarbon solvents and contain an organic compound, particularly
protective or decorative coating, ink, fountain solution, adhesive,
agricultural and electronics processing compositions containing
organic compounds such as polymeric resins, organic bases,
herbicides, fungicides, insecticides or plant growth modifying
agents. It is desirable that an aqueous solution of the citramide
demonstrates a dynamic surface tension of less than 50 dynes/cm at
a concentration of .ltoreq.5 wt % in water at 25.degree. C. and 20
bubble/second according to the maximum-bubble-pressure method.
[0039] In one aspect of the invention the citramides of the above
formula display excellent ability to reduce equilibrium and dynamic
surface tension while producing substantially no foam.
[0040] These materials may be prepared by the reaction of primary
amines with citric acid or citric acid esters. The reaction is
illustrated below: 4
[0041] The amination reaction to form the amide may be performed
using a variety of conditions well known in the organic chemical
art as described in the Kirk-Othmer Encyclopedia of Chemical
Technology, 4.sup.th Ed., Vol. 2, p. 348-351. The preferred method
involves the reaction of a citric acid ester with 3 or more
equivalents of amine in a protic solvent.
[0042] All primary amines or mixtures of primary amines containing
the requisite C1 to C18 alkyl substituents may be utilized for the
preparation of the tri-alkylcitramides of this invention, with
amines containing 2-8 carbons being preferred and those containing
3-5 carbons being especially preferred. It is preferred that the
tri-alkylcitramides contain a total of 8-20 amide alkyl carbons and
those containing a total of 9-15 amide alkyl carbons are especially
preferred. Alkyl groups which are suitable should have sufficient
carbon atoms to confer surface activity (i.e. an ability to reduce
the surface tension of water) to the material but not enough carbon
atoms to decrease the solubility to the extent that the ability of
the material to reduce surface tension is insufficient for a
particular application. In general, an increase in the carbon
number increases the efficiency of the resulting tri-alkylcitramide
(i.e. less surfactant is required to obtain a given decrease in
surface tension), but it decreases the surfactant's ability to
reduce surface tension at high surface creation rates. The latter
effect is a result of the fact that increased carbon number
generally decreases the water solubility of the material, and
consequently, diminishes the diffusive flux of surfactant to
newly-created surfaces. Generally, in the practice of this
invention, it is desirable to choose amide alkyl groups such that
the resulting tri-alkylcitramides have a solubility limit in water
of .ltoreq.10 wt % and preferably from 0.1 to 0.5 wt %.
[0043] The alkyl groups in the citramides may be the same or
different and may be linear or branched. Examples of suitable alkyl
groups are methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl,
sec-butyl, n-pentyl, 2-pentyl, 3-pentyl, iso-pentyl, neopentyl,
cyclopentyl, 2-methylbutyl, 3-methyl-2-butyl, n-hexyl, 2-hexyl,
3-hexyl, cyclohexyl, 2-ethylbutyl, 4-methyl-2-pentyl, n-heptyl,
n-octyl, n-2-ethylhexyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl and
so on. Of these derivatives those which contain a total of 8 to 20
amide alkyl carbons are preferred and those containing 9 to 15
alkyl carbons especially preferred, with those containing 12 alkyl
carbons being the most preferred, especially in the case where
R.sub.1=R.sub.2=R.sub.3=butyl.
[0044] An amount of tri-alkylcitramide that is effective to reduce
the equilibrium and/or dynamic surface tension of the water-based,
organic compound-containing composition may range from 0.001 to 20
wt %, preferably 0.01 to 10 wt %, of the aqueous composition.
Naturally, the most effective amount will depend on the particular
application and the solubility of the citramide.
[0045] The citramides are suitable for use in an aqueous
composition comprising in water an inorganic compound which is, for
example, a mineral ore or a pigment or an organic compound which is
a pigment, a polymerizable monomer, such as addition, condensation
and vinyl monomers, an oligomeric resin, a polymeric resin, a
detergent, a cleaning agent, a dissolution agent such as
trimethylammonium hydroxide (TMAH), a herbicide, a fungicide, an
insecticide, or a plant growth modifying agent.
[0046] In the following water-based organic coating, ink, adhesive,
fountain solution, agricultural and photoresist developer
compositions containing a tri-alkylcitramide according to the
invention, the other listed components of such compositions are
those materials well known to the workers in the relevant art.
[0047] A typical water-based protective or decorative organic
coating composition to which the tri-alkylcitramide surfactants of
the invention may be added would comprise in an aqueous medium 30
to 80 wt % of a coating composition containing the following
components:
1 Water-Based Organic Coating Composition 0 to 50 wt % Pigment
Dispersant/Grind Resin 0 to 80 wt % Coloring Pigments/Extender
Pigments/Anti-Corrosive Pigments/Other Pigment Types 5 to 99.9 wt %
Water-Borne/Water-Dispersible/Water-Soluble Resins 0 to 30 wt %
Slip Additives/Antimicrobials/Processing Aids/ Defoamers 0 to 50 wt
% Coalescing or Other Solvent 0.01 to 10 wt % Surfactant/Wetting
Agent/Flow and Leveling Agents 0.01 to 5 wt %
Tri-alkylcitramide
[0048] A typical water-based ink composition to which the citramide
surfactants of the invention may be added would comprise in an
aqueous medium 20 to 60 wt % of an ink composition containing the
following components:
2 Water-Based Ink Composition 1 to 50 wt % Pigment 0 to 50 wt %
Pigment Dispersant/Grind Resin 0 to 50 wt % Clay base in
appropriate resin solution vehicle 5 to 99.9 wt %
Water-Borne/Water-Dispersible/Water-Soluble Resins 0 to 30 wt %
Coalescing or Other Solvent 0.01 to 10 wt % Surfactant/Wetting
Agent 0.01 to 10 wt % Processing Aids/Defoamers/Solubilizing Agents
0.01 to 5 wt % Tri-alkylcitramide
[0049] A typical water-based agricultural composition to which the
citramide surfactants of the invention may be added would comprise
in an aqueous medium 0.1 to 80 wt % of an agricultural composition
containing the following components:
3 Water-Based Agricultural Composition 0.1 to 50 wt % Pesticide,
Insecticide, Herbicide or Plant Growth Modifying Agent 0.01 to 10
wt % Surfactant 0 to 5 wt % Dyes 0 to 20 wt %
Thickeners/Stabilizers/Co-surfactants/Gel Inhibitors/ Defoamers 0
to 25 wt % Antifreeze 0.01 to 50 wt % Tri-alkylcitramide
[0050] A typical water-based fountain solution composition
containing the citramide surfactants of the invention would
comprise the following components:
4 Water-Based Fountain Solution 0.05 to 10 wt % Film formable,
water soluble macromolecule 1 to 25 wt % Alcohol, glycol, or polyol
with 2-12 carbon atoms, water soluble or can be made to be water
soluble 0.01 to 20 wt % Water soluble organic acid, inorganic acid,
or a salt thereof 30 to 70 wt % Water 0.01 to 5 wt %
Tri-alkylcitramide
[0051] A typical water-based adhesive composition to which the
tri-alkylcitramide surfactants of the invention may be added would
comprise in an aqueous medium 30 to 65 wt % of an adhesive
composition containing the following components:
5 Water-Based Adhesive 50 to 99 wt % Polymeric Resin (SBR, VAE,
Acrylic) 0 to 50 wt % Tackifier 0 to 0.5 wt % Defoamer 0.5 to 2 wt
% Tri-alkylcitramide
[0052] A typical water-based photoresist developer, or electronic
cleaning, composition to which the tri-alkylcitramide surfactants
of the invention may be added would comprise an aqueous medium
containing the following components:
6 Water-Based Photoresist Developer Composition 0.1 to 3 wt %
Tetramethylammonium Hydroxide 0 to 4 wt % Phenolic Compound 10 to
10,000 ppm Tri-alkylcitramide
[0053] The following Examples 1-4 illustrate the synthesis of
various citric acid tri-alkylamides. All tri-alkylcitramides were
synthesized and characterized via a combination of Gas
Chromatography (GC) and Gas Chromatography/Mass Spectrometry
(GC/MS) or Nuclear Magnetic Resonance (NMR) spectroscopy. All
citramides prepared ranged from 80% to >99% pure.
EXAMPLE 1
[0054] N,N',N"-tri-n-propylcitramide was prepared by the reaction
of n-propylamine with triethylcitrate. To a round-bottomed flask
were added triethylcitrate (30.245 g; 1 eq), n-propylamine (19.427
g; 3.16 eq) and methanol (40 mL). The clear light yellow solution
stirred for 3 days at room temperature prior to the removal of
methanol via rotary evaporation at 50.degree. C. The resulting
yellow liquid was dried in vacuo at 70.degree. C. and a tacky white
solid was obtained. The crude solid was triturated using
diethylether, collected via filtration and dried in vacuo to give a
white powder with a slight odor (19.1 9g; 55% yield).
EXAMPLE 2
[0055] N,N',N"-tri-n-butylcitramide was prepared by the reaction of
n-butylamine with triethylcitrate. To a round-bottomed flask were
added triethylcitrate (31 .485 g; 0.1140 mole, 1 eq) and methanol
(40 mL). To this solution, n-butylamine (24.999g; 3.00 eq) was
slowly poured. The clear light yellow solution stirred for 3 days
at room temperature prior to the removal of methanol via rotary
evaporation at 60.degree. C. The resulting crude tacky solid was
triturated using diethylether, collected via filtration and dried
in vacuo to give a white powder with a slight amine odor (23.95 g;
58% yield).
EXAMPLE 3
[0056] N,N',N"-tri-iso-butylcitramide was prepared by the reaction
of iso-butylamine with triethylcitrate. To a round-bottomed flask
were added triethylcitrate (30.001 g; 1 eq), iso-butylamine (24.034
g; 3.03 eq) and methanol (40 mL). The clear light yellow solution
stirred for 2 days at room temperature and then additional
isobutylamine (3.06 eq) was added. After stirring overnight, a wet
white solid was observed. Methanol was removed in vacuo and the
solid was triturated using diethylether, collected via filtration
and dried in vacuo to give a white powder with no detectable odor
(31.09 g; 80.3% yield).
EXAMPLE 4
[0057] N,N',N"-tri-iso-amylcitramide was prepared by the reaction
of iso-amylamine with triethylcitrate. To a round-bottomed flask
were added triethylcitrate (30.001 g, 1 eq), iso-amylamine (28.399
g, 3.0 eq) and methanol (40 mL). The clear light yellow solution
stirred for 2 days at room temperature and then additional amine
(1.1 eq) was added. After stirring 1 week, a clear yellow solution
was observed. Methanol was removed in vacuo and the resulting white
solid was triturated using diethylether, collected via filtration
and dried in vacuo to give a white powder with a very slight odor
(22.52 g, 52.1% yield).
[0058] EXAMPLES 5-8
[0059] Solutions of the citramides of Examples 1-4 in distilled
water were prepared. Dynamic surface tension data were obtained
using the maximum-bubble pressure method at bubble rates from 0.1
bubbles/second (b/s) to 20 b/s as described in Langmuir 1986, 2,
428-432. These data provide information about the performance of a
surfactant at conditions from near-equilibrium (0.1 b/s) through
extremely high surface creation rates (20 b/s). In practical terms,
high bubble rates correspond to high printing speeds in
lithographic printing, high spray or roller velocities in coating
applications, rapid application rates for agricultural products and
electronics cleaning and processing.
[0060] The dynamic surface tension data and solubility limits are
provided in Table 1. The solubility limits of Examples 6 and 7 were
determined by intersection of the linear portion of a surface
tension/ln (concentration) curve with the limiting surface tension
as is described in many textbooks. Since Example 8 contained
insoluble material at 0.005 wt %, the solubility limit is reported
as <0.005 wt %. Also, the solubility limit of .about.10 wt %
reported for Example 1 is the lowest concentration at which a
significant amount of insoluble material was seen. The relative
efficiency of surfactants can be obtained by comparing surface
tension reduction of solutions containing the same amount of
different surfactants. Such data is given for 0.1 wt % solutions of
the tri-alkylcitramides at 1.0 and 6.0 b/s. The limiting surface
tensions at 0.1, 1, 6 and 20 b/s represent the lowest surface
tensions in water which can be achieved at the given surface
creation rates for a given surfactant regardless of the amount of
surfactant used and is used to evaluate the effectiveness of a
surfactant. These values give information about the relative
ability of a surfactant to reduce surface defects under
near-equilibrium conditions (0.1 b/s) through very dynamic
conditions (20 b/s). Lower surface tensions would allow the
elimination of defects upon application of a formulation onto lower
energy surfaces.
7TABLE 1 Surface Tension Data for Tri-alkylcitramide Surfactants
solubility .gamma. limiting.sup.b .gamma. (0.1 wt % solution).sup.b
Structure limit.sup.a (0.1 b/s) (1 b/s) (6 b/s) (20 b/s) (1 b/s) (6
b/s) Example 5 (Example 1) 5 .about.10 42.9 43.1 43.7 44.9 66.7
67.2 Example 6 (Example 2) 6 0.4 43.6 43.9 44.6 46.2 51.2 52.6
Example 7 (Example 3) 7 0.2 46.6 46.8 47.3 48.4 51.8 52.5 Example 8
(Example 4) 8 <0.005 51.6.sup.c 62.6.sup.c 67.0.sup.c 71.4.sup.c
63.3 66.6 .sup.aWeight % .sup.bDyne/cm .sup.cLimiting .gamma. at
0.005 wt. % surfactant
[0061] When the triisoamylamide (Ex 4) used in Example 8 was added
to water at 5 wt %, a considerable amount of material remained
undissolved. Measuring the dynamic surface tension of this aqueous
mixture gave the following .gamma. values: 45.7 dyne/cm (0.1 b/s)
45.9 dyne/cm (1 b/s), 46.4 dyne/cm (6 b/s) and 47.4 dyne/cm (20
b/s).
[0062] The data in Table 1 illustrate that the tri-alkylcitramides
have the ability to reduce the dynamic surface tension of an
aqueous composition and that in the majority of cases low surface
tension can be maintained even under conditions in which surface is
created at a rapid rate (i.e. 20 b/s). Examples 5-8 demonstrate
that tri-alkylcitramides containing 9 to 15 carbon atoms exhibit
surface tension values of less than 48 dyne/cm at a concentration
of .ltoreq.10 wt % in water at 25.degree. C. and at 0.1 b/s.
Furthermore, tri-alkyl-citramides containing 12 carbon atoms
demonstrate a reduction in the dynamic surface tension of aqueous
solutions to less than 50 dyne/cm under very dynamic conditions (20
b/s) and at a concentration of .ltoreq.0.5 wt % in water at
25.degree. C. In comparison, tri-alkyl-citramides containing 9
carbon atoms require a much larger amount of sample to achieve
similar dynamic surface tension reduction. Surprisingly,
tri-alkylcitramides which contain C4 groups exhibit an optimum
combination of effectiveness and efficiency in regard to surface
tension reduction of aqueous compositions.
[0063] Alkyl group branching was not found to result in improved
performance. In comparison to N,N',N"-tri-iso-butylcitramide,
N,N',N"-tri-n-butylcitramide was more soluble and thus, more
effective reducing the dynamic surface tension of water. Therefore,
of the tri-alkylcitramides which contain linear alkyl chains are
preferred for the reduction of surface tension of water in
water-based, organic compound containing compositions, including
waterborne coatings, inks, adhesives, fountain solutions,
agricultural formulations and electronics cleaning compositions.
However, ultimately the choice of tri-alkylcitramide will depend
upon the application.
EXAMPLES 9-13
[0064] The foaming properties of a 0.1 wt % solutions of the
tri-alkylcitramides (N,N',N"-tri-n-propylcitramide, N,N',
N"-tri-n-butylcitramide, N,N',N"-tri-iso-butylcitramide and
N,N',N"-tri-iso-amylcitramide) were examined using a procedure
based upon ASTM D 1173 - 53. In this test, a 0.1 wt % solution of
the citramide surfactant was added from an elevated glass pipette
to a receiver containing the same solution. The foam height was
measured at the completion of the addition ("Initial Foam Height")
and the time required for the foam to dissipate at the air-liquid
interface ("Time to 0 Foam") was recorded. This test provided a
comparison between the foaming characteristics of the various
citramides. In general, in coatings, inks, adhesives, agricultural
and electronics cleaning formulations, foam is undesirable because
it complicates handling and can lead to coating and print defects,
and to inefficient application of materials. The results for the
tri-alkylcitramides prepared in Examples 1-4 are reported in Table
2.
8TABLE 2 Foam Test Data initial foam Structure (cm) time to zero
foam Example 9 (Example 1) 9 2.8 10 sec Example 10 (Example 2) 10
1.3 9 sec Example 12 (Example 3) 11 1.0 10 sec Example 13 (Example
4) 12 1.3 2 sec
[0065] A drawback to the use of many conventional surfactants in
coatings, inks, adhesives, agricultural, electronic chemical and
cleaning formulations is the formation of considerable quantities
of long-lasting foam in these systems. For such applications, it is
desired that a surfactant form as little foam as possible and that
the foam which forms dissipates quickly. The data in Table 2 show
that the compounds of this invention formed very little initial
foam and that the foam which formed dissipated quickly. Therefore,
in addition to their ability to reduce the surface tension of
organic-containing aqueous compositions under both equilibrium and
dynamic conditions, tri-alkylcitramide surfactants have desirable
foam properties with respect to their use in coatings, inks,
adhesives, agricultural and electronics cleaning formulations.
STATEMENT OF INDUSTRIAL APPLICATION
[0066] The invention provides compositions suitable for reducing
the equilibrium and dynamic surface tension in water-based coating,
ink, adhesive, fountain solution, agricultural and electronics
cleaning compositions.
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