Alcoholic marking ink composition

An alcoholic marking ink composition comprises a coloring agent, a solvent mainly composed of ethanol, a condensation product of urea and aliphatic aldehydes as a resin to be added, and a cationic surface active agent.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an ink composition for alcoholic marking 
pens. 
2. Description of the Prior Art 
Heretofore, oil based marking pens often called "sign pens" or "felt pens" 
have been using xylenes, cellosolve or ketones as a main solvent for the 
ink. Therefore, there are problems such as the undesirable odor and 
toxicity to man and there is a possibility that methods of using such 
solvents and environment where such solvents are used may be limited. 
These solvents solve the surface of a material on which writing is made 
with the marking ink, due to their solving property. Therefore, the 
writing characteristics required for the marker are problematic when the 
marker is used for writing on widely used materials. 
Japanese Patent Application Laid-open No. 128404/1978 discloses an ink 
composition where a fluorine type surface active agent is added to an oil 
based ink composition so as to impart water resistance and oil resistance 
to the written images. However, this ink composition is concerned with an 
oil based ink which has problems adversely affecting man such as odor, 
toxicity and the like. 
There is not known any ink composition comprising a solvent mainly composed 
of an alcohol to which the above-mentioned technique is applied. 
In order to eliminate those disadvantages, ink compositions comprising 
ethanol as a substitute for oils have been investigated, but since the 
resins added for imparting fixability are soluble in ethanol and have 
affinity to both water and oil and fat to some extent due to the molecular 
structure of the resins, both water resistance and oil resistance of the 
ink composition become poor. 
SUMMARY OF THE INVENTION 
An object of the present invention is to provide an alcoholic marking ink 
composition usable for writing on the surface of various materials. 
Another object of the present invention is to provide an alcoholic marking 
ink composition having an excellent written image fixability to a 
non-absorbing surface. 
A further object of the present invention is to provide an alcoholic 
marking ink composition having excellent water resistance and excellent 
oil resistance of written images though an alcoholic solvent is used. 
Still another object of the present invention is to provide an alcoholic 
marking ink composition substantially free from odor. 
A still further object of the present invention is to provide an alcoholic 
marking ink composition of less toxicity. 
According to the present invention, there is provided an alcoholic marking 
ink composition comprising a coloring agent, a solvent mainly composed of 
ethanol, a condensation product of urea and aliphatic aldehydes, as a 
resin to be added, and a cationic surface active agent. 
DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The coloring agents used in the present invention are dissolved or 
dispersed in a solvent mainly composed of ethanol. The coloring agents may 
be dyes and pigments usually used for writing instruments and inks for 
coating. 
Exemplary suitable dyes are basic dyes, acid dyes, direct dyes and the 
like. 
As pigments, there may be used inorganic pigments and organic pigments. 
Exemplary suitable inorganic pigments are titanium oxide, iron black, red 
iron oxide and the like. Exemplary suitable organic pigments are azo type 
pigments, phthalocyanine type pigments, anthraquinone type pigments, 
indigo type pigments and the like. 
As dyes, solubilized dyes and dyes enclosed in microcapsules may be also 
used, and as pigments, there may be used in the form of a dispersed mill 
base comprising a pigment of which the surface is modified with a resin or 
surface active agent. 
The amount of coloring agents to be added is not particularly critical, and 
may be an amount determined depending on the solubility or dispersion 
property of the coloring agent, desired hue and color density. The range 
of the amount may be wide and is usually 0.1-50 % by weight based on the 
total ink composition. 
The solvent used in the present invention is mainly composed of ethanol 
which is less toxic and is of quickdrying. The total amount of the solvent 
is preferably 40-95% by weight based on the total ink composition. The 
amount of ethanol is preferably 80% by weight or more based on the total 
amount of the solvent. Other solvent may be added to ethanol as an 
anxiliary solvent for various purposes. 
As an auxilary solvent for dye, a whitening preventing agent or a 
dispersion auxiliary solvent, there may be used isopropyl alcohol, benzyl 
alcohol and the like. As an agent for preventing a pen point from drying, 
there may be used ethylene glycol, propylene glycol and the like. 
The total amount of solvents other than ethanol is preferably 20% by weight 
or less based on the total amount of the solvent. 
The condensation product of urea and aliphatic aldehydes is used in the 
present invention so as to improve the fixability of written images such 
as written lines and the like. 
Exemplary suitable condensation products of urea and aliphatic aldehydes 
are Laropal A81 (trade name, supplied by BASF) and Laropal A101 (trade 
name, supplied by BASF). 
The molecular weight and amount to be added of the condensation product are 
not particularly critical as far as the molecular weight and amount are 
suitable for the required fixing power and ink viscosity. The amount to be 
add is preferably 5-30% by weight based on the total ink composition. If 
desired, other resins, plasticizers and the like may be added to the 
condensation product of urea and aliphatic aldehydes. 
As the cationic surface active agent, there may be preferably used 
perfluoroalkyl quaternary ammonium salt. The cationic surface active agent 
can improve water resistance and oil resistance of the ink composition 
when used together with the above-mentioned condensation product of urea 
and aliphatic aldehydes. 
Exemplary suitable cationic surface active agents include alkyl amine 
acetate, alkyl dimethylamine oxide, alkyl picoline chloride, alkyl 
betaine, alkyl dimethylbenzyl ammonium salt, stearyl trimethyl ammonium 
salt, and perfluoroalkyl quaternary ammonium salt. 
The amount of the cationic surface active agent to be added is usually 
0.01-3.0% by weight based on the total ink composition. When the amount is 
less than 0.01% by weight, the effect is decreased. When the amount is 
more than 3.0% by weight, sometimes the written lines are repelled. 
The interaction between the condensation product of urea and aliphatic 
aldehydes and the cationic surface active agent is one of the most 
important points. 
The alcoholic marking ink composition according to the present invention 
can be applied to a surface of various materials such as, for example, 
papers, resins, metals and the like. In particular, it can be applied to 
even a non-absorbing surface of materials. 
When lines are written on an absorptive writing surface such as paper with 
an oil based marking pen, the resulting lines have no problem, but when 
written on a non-absorptive surface, fixability of written lines is 
different depending on the surface properties of the material. Thus, there 
is not yet a widely usable oil based marking ink at present. 
The above-mentioned problem can be solved to some extent by substituting 
ethanol for the solvent system. However, when ethanol which has 
intermediate properties between water and oil is used as a solvent, the 
resin dissolved in ethanol also exhibits amphoteric behaviors and thereby 
both water resistance and oil resistance become incomplete. 
However, when the condensation product of urea and aliphatic aldehydes of 
the present invention is contained in the ink composition, the ink 
composition exhibits good fixability to a polar surface such as a surface 
of a metal plate as well as a non-polar surface such as a surface of a 
polypropylene (PP) plate, and further exhibits both excellent water 
resistance and oil resistance. 
The reason for such good results is not clear, but this seems to be 
attributable to an interaction between the resin molecule and the cationic 
surface active agent though it is not contemplated that the present 
invention is limited to a particular mechanism. 
In addition, since the ink composition of the present invention uses 
ethanol as a less toxic and low stimulative solvent, the ink composition 
substantially does not adversely affect the writing surface of a material 
such as resins and is substantially safe to man. 
The following examples are set forth for purposes of illustration only and 
are not to be construed as limitations on the present invention. 
All parts are by weight unless otherwise specified.

In the following both working examples of the present invention and 
comparison examples are shown. 
EXAMPLE 1 
______________________________________ 
Carbon black 8.0 parts 
Polyvinylbutyral 6.0 parts 
(S lex B, BM-1, 
supplied by Sekisui 
Kagaku K.K.) 
Condensation product 
13.0 parts 
of urea and aliphatic 
aldehydes 
(Laropal A101, 
supplied by BASF) 
Perfluoroalkyl quaternary 
0.2 parts 
ammonium iodide 
Ethanol 58.2 parts 
Isopropyl alcohol 14.6 parts 
______________________________________ 
COMATIVE EXAMPLE 1 
Perfluoroalkyl quaternary ammonium was not added. 
______________________________________ 
Carbon black 8.0 parts 
Polyvinylbutyral 6.0 parts 
(S lex B, BM-1, 
supplied by Sekisui 
Kagaku K.K.) 
Condensation product 
13.0 parts 
of urea and aliphatic 
aldehydes 
(Laropal A101, 
supplied by BASF) 
Ethanol 58.4 parts 
Isopropyl alcohol 14.6 parts 
______________________________________ 
COMATIVE EXAMPLE 2 
Any condensation product of urea and aliphatic aldehydes as a resin to be 
added was not incorporated. 
______________________________________ 
Carbon black 8.0 parts 
Polyvinylbutyral 6.0 parts 
Rosin-modified 13.0 parts 
maleic acid resin 
Perfluoroalkyl 0.2 parts 
quaternary 
ammonium iodide 
Ethanol 58.2 parts 
Isopropyl alcohol 14.6 parts 
______________________________________ 
EXAMPLE 2 
______________________________________ 
Oil blue #613 (trade name, 
6.0 parts 
supplied by Orient Kogaku 
Kogyo K.K.) 
Condensation product 
10.0 parts 
of urea and aliphatic 
aldehydes 
(Laropal A81, 
trade name, supplied by 
BASF) 
Perfluoroalkyl quaternary 
0.3 parts 
ammonium iodide 
Ethanol 80.7 parts 
Benzyl alcohol 3.0 parts 
______________________________________ 
COMATIVE EXAMPLE 3 
Conventional formula; the resin and solvent are different from those of the 
present invention and a surface active agent is not added. 
______________________________________ 
Oil blue #613 (trade name, 
6.0 parts 
supplied by Orient Kogaku 
Kogyo K.K.) 
Ketone resin 15.0 parts 
Xylene 66.0 parts 
Ethylcellosolve 13.0 parts 
______________________________________ 
The resulting compositions in the Examples and comparative Examples were 
evaluated with respect to various properties. The results are shown in 
Table 1. 
TABLE 1 
______________________________________ 
Comparative 
Example No. 
Example No. 
1 2 1 2 3 
______________________________________ 
Fixability 
Metal plate 
.largecircle. 
.largecircle. 
.largecircle. 
.smallcircle. 
.smallcircle. 
PP plate .smallcircle. 
.smallcircle. 
.smallcircle. 
.DELTA. 
.smallcircle. 
ABS plate .smallcircle. 
.largecircle. 
.smallcircle. 
.DELTA. 
x 
Water resistance 
Metal plate 
.largecircle. 
.largecircle. 
.DELTA. .DELTA. 
.smallcircle. 
PP plate .smallcircle. 
.smallcircle. 
x x .smallcircle. 
ABS plate .smallcircle. 
.smallcircle. 
x x x 
Oil resistance 
Metal plate 
.largecircle. 
.largecircle. 
.DELTA. .DELTA. 
x 
PP plate .smallcircle. 
.smallcircle. 
.DELTA. x x 
ABS plate .smallcircle. 
.smallcircle. 
.DELTA. x x 
Smell .smallcircle. 
.smallcircle. 
.smallcircle. 
.smallcircle. 
x 
______________________________________ 
PP plate: polypropylene plate 
ABS plate: Acrylonitrilebutadiene-styrene resin plate 
.smallcircle.: Very good 
.largecircle.: Good 
.DELTA.: Somewhat poor 
x: Poor 
The evaluation was made by fabricating a marking pen using the ink, drawing 
lines on each plate, rubbing the lines thus drawn and observing the drawn 
lines thus rubbed by eyes. 
Fixability: After writing, the written lines were dried for one hour and 
then evaluated. 
Water resistance: After writing, the written lines were dried for one hour 
and allowed to stand in water for 3 days, and then evaluated. 
Oil resistance: A machine oil was applied to a surface of a plate and then 
writing was made on the surface thus coated with the machine oil and the 
resulting writing was evaluated.