U.S. patent application number 11/406370 was filed with the patent office on 2006-08-24 for preparation of yellow pigment.
Invention is credited to Terence R. Chamberlain, Kimberly A. Clark, Russell J. Schwartz, Norman W. Smith.
Application Number | 20060189726 11/406370 |
Document ID | / |
Family ID | 34701286 |
Filed Date | 2006-08-24 |
United States Patent
Application |
20060189726 |
Kind Code |
A1 |
Smith; Norman W. ; et
al. |
August 24, 2006 |
Preparation of yellow pigment
Abstract
A process for preparing transparent Pigment Yellow 138 by
grinding Pigment Yellow 138 in the presence of a grinding agent,
preparing an aqueous slurry of the ground particles, and filtering
the slurry resulting in a filter cake containing particles of
transparent Pigment Yellow 138. In addition, a process for
improving color strength of an ink and/or plastic composition is
also disclosed by adding transparent Pigment Yellow 138 to the
composition.
Inventors: |
Smith; Norman W.;
(Cincinnati, OH) ; Schwartz; Russell J.;
(Montgomery, OH) ; Clark; Kimberly A.;
(Cincinnati, OH) ; Chamberlain; Terence R.;
(Montgomery, OH) |
Correspondence
Address: |
DICKSTEIN SHAPIRO MORIN & OSHINSKY LLP
1177 AVENUE OF THE AMERICAS (6TH AVENUE)
41 ST FL.
NEW YORK
NY
10036-2714
US
|
Family ID: |
34701286 |
Appl. No.: |
11/406370 |
Filed: |
April 19, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10751245 |
Dec 31, 2003 |
7060835 |
|
|
11406370 |
Apr 19, 2006 |
|
|
|
Current U.S.
Class: |
524/90 ;
546/154 |
Current CPC
Class: |
C09D 11/037 20130101;
C09B 67/0022 20130101; C09B 67/0002 20130101; C09D 7/41
20180101 |
Class at
Publication: |
524/090 ;
546/154 |
International
Class: |
C07D 215/20 20060101
C07D215/20; C08K 5/34 20060101 C08K005/34 |
Claims
1. Transparent Pigment Yellow 138 prepared by (a) grinding Pigment
Yellow 138 in the presence of a grinding agent to obtain ground
pigment; (b) preparing an aqueous slurry of said ground pigment;
(c) filtering said slurry resulting in a filter cake containing
transparent Pigment Yellow 138; and (d) drying said filter cake to
obtain ransparent Pigment Yellow 138.
2. The transparent Pigment Yellow 138 of claim 1 consisting of
particles having a surface area of greater than about 50
m.sup.2/g.
3. The transparent Pigment Yellow 138 of claim 2 wherein the
particles have a surface area of from about 50 m.sup.2/g to about
100 m.sup.2/g.
4. An ink composition having a color strength that has been
improved by the addition of the transparent Pigment Yellow 138 of
claim 1.
5. The ink composition of claim 4 wherein the transparent Pigment
Yellow 138 consists of particles whose surface area is greater than
about 50 m.sup.2/g.
6. The ink composition of claim 5 wherein the particles have a
surface area of from about 50 m.sup.2/g to about 100 m.sup.2/g.
7. A plastic composition having a color strength that has been
improved by the addition of the transparent Pigment Yellow 138 of
claim 1.
8. The plastic composition of claim 7 wherein the transparent
Pigment Yellow 138 consists of particles whose surface area is
greater than about 50 m.sup.2/g.
9. The plastic composition of claim 8 wherein the particles have a
surface area of from about 50 m.sup.2/g to about 100 m.sup.2/g.
Description
CROSS-REFERENCE
[0001] This application is a divisional application of U.S. Ser.
No. 10/751,245 filed Dec. 31, 2003 which is hereby incorporated by
reference in its entirety.
FIELD OF THE INVENTION
[0002] The invention relates to the preparation of transparent
Pigment Yellow 138.
BACKGROUND OF THE INVENTION
[0003] Pigment Yellow 138 is well known to be a very lightfast and
weatherfast green-shade yellow pigment with good heat stability.
Pigment Yellow 138, also known as quinophthalone, is typically used
in plastics and paint applications. The most common commercial
Pigment Yellow 138 has a relatively low specific surface area of
approximately 25 m.sup.2/g, which gives good hiding power in
systems where opacity is desirable. For most ink systems however,
it is desirable to have a high degree of transparency, therefore,
pigments having a high specific surface area are required.
[0004] Pigment Yellow 138 may be prepared by various means of
comminution, including ball milling or kneading in the presence of
a grinding agent. However, it has not been know how to prepare
Pigment Yellow 138 having a high surface area exhibiting strong
color strength and transparency while also having
lightfastness.
[0005] The preparation of quinophthalone pigments is described in
the prior art. For example, condensation of 2-methylquinoline
derivatives (quinaldine derivatives) with aromatic
ortho-dicarboxylic acids or their anhydrides is carried out in the
presence of inert high-boiling diluents such as
ortho-dichlorobenzene, trichlorobenzene, nitrobenzene, naphthalene,
diphenyl or diphenyl ether (Chimia 24, 328,1970; GB-A1,091,734).
U.S. Pat. No. 5,106,980 discloses a process for the preparation of
quinophthalones by condensation of 8-aminoquinaldine with phthalic
anhydride optionally monosubstituted or polysubstituted by chlorine
or bromine, in the presence of a diluent, resulting in relatively
low specific surface area and opaque pigment. U.S. Pat. No.
3,622,583 describes a process for the preparation of yellow dye
quinophthalone derivatives by heating 8-aminoquinaldine with
tetrachlorophthalic anhydride or tetrabromophthalic anhydride in
the presence of other solvents and at a temperature of
130-300.degree. C. According to the Industrial Organic Pigments, by
Herbst, W. and Hunger, K. VCH., Yellow 138 pigments that possess
higher surface area exhibit somewhat lower lighffastness
properties. However, the prior art processes result in relatively
low specific surface area Pigment Yellow 138 and therefore are
mostly opaque.
[0006] Thus, there exists a need for Pigment Yellow 138 having
increased transparency and lighffastness while maintaining standard
coloristic properties in a printing ink such as color strength and
tint strength.
SUMMARY OF THE INVENTION
[0007] It has now been found that the above objectives can be
realized by a process for preparing transparent Pigment Yellow 138
comprising:
(a) grinding Pigment Yellow 138 in the presence of a grinding
agent;
(b) preparing an aqueous slurry of the ground pigment;
(c) filtering said slurry resulting in a filter cake containing
particles of transparent 25 Pigment Yellow 138.
[0008] The present invention also provides a process for improving
transparency and color strength in an ink or a plastic composition
comprising adding transparent Pigment Yellow 138 to said
composition.
[0009] Other objects and advantages of the present invention will
become apparent from the following description and appended
claims.
DETAILED DESCRIPTION OF INVENTION
[0010] The present invention is a process for preparing a more
transparent Pigment Yellow 138 which surprisingly exhibits little
if any loss in strength, chroma or shade in the ink masstone while
exhibiting good lighffastness.
[0011] The process is a mill process which may be carried out in
any conventional apparatus such as a kneader, ball mill apparatus
or any suitable such container. The process combines Pigment Yellow
138 and salt which are milled, with a wetting agent as necessary,
and then the prepared pigment is isolated with water, heated, and
dried.
[0012] The starting pigment is any Pigment Yellow 138 or
quinophthalone yellow, such as that commercially available from
BASF-0961. Typically, between half to three parts pigment is
used.
[0013] Suitable salts for use in the process include, but are not
limited to inorganic salts, sodium chloride, sodium sulfate,
calcium chloride, calcium sulfate, and the like, and combinations
thereof. A preferred salt is sodium chloride. Typically, the salt
is between about 1 to about 20 parts based on the starting
pigment.
[0014] Suitable wetting agents for use in the process may include,
but are not limited to, water miscible solvents and glycolic
solvents such as ethylene glycol, diethylene glycol, propylene
glycol, dipropylene glycol, polypropylene glycol, propylene
carbonate, carbitol acetate, and the like. It is preferred that the
wetting agent is diethylene glycol.
[0015] The starting pigment and salt are combined in a mill
container and milled at a temperature of about 50.degree. C. to
about 100.degree. C. for about thirty minutes to about 7 hours. It
is preferred that the temperature be about 80-100.degree. C. and
the milling continue for about 1 to about 2 hours.
[0016] If a kneader is used, then the wetting agent is added. If a
ball mill is used then balls are added, which may be of any
appropriate material, such as, but not limited to glass, zirconium
oxide, and the like. The balls typically have a size of about
0.5-10 mm and are added at about 100 to 200 parts based on the
pigment.
[0017] Upon completion of the milling process, the mixture is
isolated by preparing an aqueous slurry through mixing the mill
contents with about 25 to about 150 parts water, then stirring at
about 30.degree. C. to about 100.degree. C. for a period of about
thirty minutes to about 3 hours. The resulting slurry is filtered
and the filter cake is thoroughly washed with tap water until
equivalent conductivity is attained, followed by deionized water,
if desired. The washed filter cake is dried at about 50.degree. C.
to about 150.degree. C.
[0018] The resultant pure and transparent Yellow Pigment 138 may be
formulated into a variety of ink systems resulting in yellow inks
which are strong, cleaner and more transparent than corresponding
inks made from the common commercial Pigment Yellow 138 while
exhibiting virtually identical lighffastness and masstone
properties. Surprisingly, little if any loss in color strength,
chroma or shade in the ink masstone was experienced upon its
exposure to light for up to 200 hours. Similar exposure of the
reduced ink film (ink tint) demonstrated only a minor decrease in
its lightfastness relative to the corresponding film of the common
commercial pigment.
[0019] The process of the present invention is further illustrated
by the following non-limiting examples in which all parts and
percentages are by weight, unless otherwise indicated.
Example I
[0020] Pigment (1 part), sodium chloride (10 parts), and diethylene
glycol (2 parts) were mixed for one hour at 88.degree. C. The
resulting slurry mixture was placed into 100 parts of water and
mixed thoroughly while maintaining temperature at 80-90.degree. C.
for one hour. The slurry was filtered and washed with tap water
until the conductivity of the filtrates was equal to that of the
wash water. The resulting solid Pigment Yellow 138 was dried and
had a surface area of 80 m.sup.2/g.
Example 2
[0021] Pigment (1 part), sodium chloride (5 parts) and glass beads
(100 parts) were milled for 3 hours, with frequent scraping down
the sides of the mill. The milled pigment was mixed with water (100
parts) at 80-90.degree. C. for one hour and the beads removed with
a coarse strainer. The aqueous slurry was filtered, washed and
dried as in Example 1. The resulting solid Pigment Yellow 138 had a
surface area of 55 m.sup.2/g
Example 3 (Comparison)
[0022] Pigment Yellow 138 of Example 1 having a surface area of 80
m.sup.2/g was tested for lighffastness compared to conventional
commercial Pigment Yellow 138 having a surface area of 25
m.sup.2/g. Both pigments were drawn down on a substrate and exposed
to light for up to 200 hours. The larger surface area pigment of
Example 1 exhibited comparable lightfastness compared to the
conventional pigment of smaller surface area.
Example 4 (Comparison)
[0023] The pigment of Example 1 having a surface area of 80
m.sup.2/g was incorporated into a typical solvent ink film and
compared with a solvent ink film containing a conventional
commercial Pigment Yellow 138 having a surface area of about 25
m.sup.2/g. Both solvent ink films were exposed to 192 hours of
sunlight under identical conditions of light, temperature and
ambient humidity, and then tested for tint strength and color
strength and CIELAB value for .DELTA.E* using the Color Tools.RTM.
from Datacolor International of Lawrenceville, N.J. The results of
the test for color strength and masstone are set forth in Table 1
below. TABLE-US-00001 TABLE 1 Pigment in the solvent ink film Tint
.DELTA.E Tint Strength Example 1 1.3 -7% Conventional 0.74 -1%
[0024] The respective masstones of each solvent ink film displayed
essentially no change in strength or .DELTA.E value (relative to
their non-exposed areas), while the corresponding ink tints
exhibited comparable color strength decreases.
Example 5 (Comparison)
[0025] The pigment of Example 1 having a surface area of 80
m.sup.2/g was incorporated into a typical aqueous ink film and
compared with an aqueous ink film containing a conventional
commercial Pigment Yellow 138 having a surface area of about 25
m.sup.2/g. Both aqueous ink films were exposed to 192 hours of
sunlight under identical conditions of light, temperature and
ambient humidity, and then tested for tint strength and color
strength according to the method of Example 4. The results of the
test for color strength and masstone are set forth in Table 1
below. TABLE-US-00002 TABLE I Pigment in the solvent ink film Tint
.DELTA.E Tint Strength Example 1 3.5 -11% Conventional 3.0 -11%
[0026] The respective masstones of each aqueous ink film displayed
essentially no change in strength or .DELTA.E value (relative to
their non-exposed areas), while the corresponding ink tints
exhibited comparable color strength decreases.
Example 6 (Comparison)
[0027] The pigment of Example 2 having a surface area of about 55
m/g was incorporated into a plastic (LDPE) and compared with a
plastic containing a conventional commercial Pigment Yellow 138
having a surface area of about 25 m.sup.2/g. Both plastics were
exposed to temperatures of between 400-525.degree. F. to test for
coloristic properties of masstone and color strength by the method
set forth in Example 4.
[0028] Little or no differences in the respective .DELTA.E values
were observable over this temperature range although the higher
surface area pigment of Example 2 exhibited a significantly
stronger shade in the tint (of 45-50%) throughout the range,
compared to the conventional pigment having surface area of about
25 m.sup.2/g.
[0029] The invention has been described in terms of preferred
embodiments thereof, but is more broadly applicable as will be
understood by those skilled in the art. The scope of the invention
is only limited by the following claims.
* * * * *