U.S. patent application number 16/757541 was filed with the patent office on 2021-06-24 for dioxazine pigment and colorant.
This patent application is currently assigned to DIC Corporation. The applicant listed for this patent is DIC Corporation. Invention is credited to Hiromasa Kikuchi, Hidehiro Otake, Shogo Yamada.
Application Number | 20210189136 16/757541 |
Document ID | / |
Family ID | 1000005461976 |
Filed Date | 2021-06-24 |
United States Patent
Application |
20210189136 |
Kind Code |
A1 |
Yamada; Shogo ; et
al. |
June 24, 2021 |
DIOXAZINE PIGMENT AND COLORANT
Abstract
An object of the present invention is to provide a dioxazine
pigment having excellent fluidity. More specifically, an object of
the present invention is to provide a dioxazine pigment in which
practically sufficient fluidity is attained in both (1) initial
viscosity and (2) storage stability when the dioxazine pigment is
used in a printing ink application. The object is attained by
providing a dioxazine pigment having a contact angle with respect
to water according to an infiltration rate method in a range of
30.degree. to 75.degree., and a contact angle with respect to
1-bromonaphthalene according to an infiltration rate method in a
range of 30.degree. to 75.degree..
Inventors: |
Yamada; Shogo; (Kamisu-shi,
JP) ; Kikuchi; Hiromasa; (Kamisu-shi, JP) ;
Otake; Hidehiro; (Kamisu-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DIC Corporation |
Tokyo |
|
JP |
|
|
Assignee: |
DIC Corporation
Tokyo
JP
|
Family ID: |
1000005461976 |
Appl. No.: |
16/757541 |
Filed: |
November 15, 2018 |
PCT Filed: |
November 15, 2018 |
PCT NO: |
PCT/JP2018/042259 |
371 Date: |
April 20, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C07D 498/22 20130101;
C09B 19/00 20130101; C09D 11/037 20130101 |
International
Class: |
C09B 19/00 20060101
C09B019/00; C09D 11/037 20060101 C09D011/037; C07D 498/22 20060101
C07D498/22 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 28, 2017 |
JP |
2017-227804 |
Claims
1. A dioxazine pigment having a contact angle with respect to water
according to an infiltration rate method in a range of 30.degree.
to 75.degree., and a contact angle with respect to
1-bromonaphthalene according to an infiltration rate method in a
range of 30.degree. to 75.degree..
2. The dioxazine pigment according to claim 1, wherein dioxazine
pigment particles have at least one hydroxy group and at least one
carbonyl group on a surface.
3. A colorant containing at least the dioxazine pigment according
to claim 1.
4. A printing ink containing at least the dioxazine pigment
according to claim 1.
Description
TECHNICAL FIELD
[0001] The present invention relates to a dioxazine pigment that
can be used in an extensive application such as a printing ink, a
coating material, a colored molded article, and textile
printing.
BACKGROUND ART
[0002] In general, a pigment for coloring contains fine particles.
For example, in a case where a pigment that is an aggregate of fine
primary particles, such as a printing ink of gravure printing,
flexo printing, or the like, or a coating material, is dispersed in
a medium, in order to loosen the aggregation of the particles,
devisal such as performing dispersion for a long period of time by
applying a strong force or adding a dispersant has been
conducted.
[0003] Among them, a dioxazine pigment represented by C.I. Pigment
Violet 23 is a pigment that is used in various situations, but
easily causes stacking structurally and tends to be rigidly
aggregated, and thus, problems relevant to fluidity are
considerable when the dioxazine pigment is used in various
applications as a colorant. Therefore, in order to improve the
fluidity, the combination of a derivative of the dioxazine pigment
has been considered (PTL 1 or the like).
[0004] However, in a method of combining a pigment derivative,
there is a case where it is not possible to sufficiently ensure the
fluidity, depending on an application.
[0005] For this reason, there is still a demand for improving a
dioxazine pigment exhibiting sufficient fluidity.
CITATION LIST
Patent Literature
[0006] PTL 1: JP-A-2011-162662
SUMMARY OF INVENTION
Technical Problem
[0007] In consideration of the circumstances as described above, an
object of the present invention is to provide a dioxazine pigment
having excellent fluidity. More specifically, an object of the
present invention is to provide a dioxazine pigment in which
practically sufficient fluidity is attained in both (1) an initial
viscosity and (2) storage stability when the dioxazine pigment is
used in a printing ink application.
Solution to Problem
[0008] The present inventors have intensively studied a mutual
interaction in a plurality of components in a printing ink in order
to find a dioxazine pigment exhibiting more excellent fluidity, and
as a result thereof, have found that the object can be attained by
preparing a dioxazine pigment to have specific contact angles with
respect to water and an organic solvent, respectively, by modifying
the surface of the pigment particles, and have completed the
present invention.
[0009] That is, the present invention relates to:
[0010] "Claim 1. A dioxazine pigment having a contact angle with
respect to water according to an infiltration rate method in a
range of 30.degree. to 75.degree., and a contact angle with respect
to 1-bromonaphthalene according to an infiltration rate method in a
range of 30.degree. to 75.degree. (hereinafter, may be referred to
as the dioxazine pigment of the present invention).
[0011] Claim 2. The dioxazine pigment according to claim 1, wherein
dioxazine pigment particles have at least one hydroxy group and at
least one carbonyl group on a surface thereof.
[0012] Claim 3. A colorant containing at least the dioxazine
pigment according to claim 1 or 2."
Advantageous Effects of Invention
[0013] According to the dioxazine pigment of the present invention,
a remarkable effect is obtained in which a dioxazine pigment having
excellent fluidity at the time of being used in a printing ink or
the like can be obtained. More specifically, when the dioxazine
pigment is used in a printing ink application, practically
sufficient performance is exhibited in both (1) an initial
viscosity and (2) storage stability. In addition, the gloss of a
printed material is also excellent. Further, the dioxazine pigment
of the present invention is not based on a derivative treatment,
and thus, it is possible to eliminate the possibility that
undesirable influence such as migration due to the derivative
treatment described above occurs.
DESCRIPTION OF EMBODIMENTS
[0014] Hereinafter, the present invention will be described in
detail.
[0015] The present invention relates to a dioxazine pigment having
a contact angle with respect to water according to an infiltration
rate method in a range of 30.degree. to 75.degree., and a contact
angle with respect to 1-bromonaphthalene according to an
infiltration rate method in a range of 30.degree. to 75.degree..
According to such a dioxazine pigment of the present invention,
excellent fluidity is exhibited even when the dioxazine pigment is
used as a printing ink or a coating material.
[0016] <Description of Dioxazine Pigment>
[0017] Examples of the dioxazine pigment used in the present
invention include C.I. Pigment Violet 23, C.I. Pigment Violet 37,
C.I. Pigment Blue 80, and the like. In particular, C.I. Pigment
Violet 23 is industrially important, and is represented by Chemical
Structural Formula (I) described below. As such C.I. Pigment Violet
23, a commercially available product (for example, FASTOGEN SUPER
VIOLET series (manufactured by DIC Corporation, Specific Surface
Area according to BET Method: 50 m.sup.2/g to 120 m.sup.2/g), and
the like) may be used, or a pigment produced by a known
conventional method may be used. The produced pigment may be
subjected to a known treatment suitably. It is preferable that the
specific surface area of the C.I. Pigment Violet 23 according to
the BET method is in a range of 60 m.sup.2/g to 80 m.sup.2/g, from
the viewpoint of preventing thickening due to excessive aggregation
of fine particles while retaining transparency.
##STR00001##
[0018] <Description of Contact Angle According to Infiltration
Rate Method>
[0019] The present inventors have found that by preparing the
dioxazine pigment in which the contact angle with respect to water
according to the infiltration rate method described below is in a
range of 30.degree. to 75.degree., and the contact angle with
respect to 1-bromonaphthalene is in a range of 30.degree. to
75.degree., excellent fluidity can be obtained in a nitrocellulose
(hereinafter, referred to as NC)-based ink and a polyurethane
(hereinafter, referred to as PU)-based ink, that is, remarkably
excellent thickening suppression can be obtained in both an initial
viscosity and storage stability.
[0020] In the idea of the configuration described above, the
present inventors have paid attention to a step of dispersing a
pigment at the time of preparing various printing inks.
[0021] In the detailed description, a dispersion step of the
dioxazine pigment includes a procedure of wetting an aggregate of
dioxazine pigment particles in a solvent, and then, a procedure of
mechanically crushing the aggregate into pigment particles, and
finally, a procedure of performing dispersion stabilization in
which a resin or the like is adsorbed on the surface of the pigment
particles in order to prevent re-aggregation. Accordingly, as the
wetting of the pigment with respect to the solvent is performed
faster, time required to proceed to the next crushing procedure is
shortened, and thus, the dispersion progresses faster. For example,
in the PU ink, in a case where the wetting with respect to the
solvent is performed fast and it is easy to proceed to the
dispersion stabilization, the initial viscosity of the PU ink
decreases and the storage stability is also excellent. In addition,
the pigment is sufficiently dispersed, and the aggregate of the
pigment particles decreases, and thus, the gloss of a printed
material increases.
[0022] Similarly, in the NC ink, the dispersion is performed fast,
in accordance with the improvement of the wettability, and the
storage stability is excellent. Here, in the case of describing the
NC ink as an example, ethanol that excellently dissolves NC and has
comparatively high safety with respect to a human body may be used
as a solvent of the NC ink. In addition, a method is known in which
the NC ink containing ethanol is diluted with ethyl acetate such
that a boiling point of the solvent is decreased, and thus, the
drying of the ink is performed faster, and printing is performed at
a high rate. When the NC ink of the dioxazine pigment is diluted
with ethyl acetate, in general, the dioxazine pigment has low
wettability and low affinity with respect to ethyl acetate, and
thus, surface free energy of the pigment particles increases, and
the stabilization is not attained. Accordingly, it is considered
that a force for reducing a surface area of the pigment particles
acts in order to decrease the surface free energy, and the
aggregation of the pigment particles occurs. For this reason, the
present inventors have considered that in a case where the
dioxazine pigment has suitable affinity with respect to ethyl
acetate and ethanol, both of the storage stability of the NC ink
containing ethanol as a main solvent and the fluidity of the NC ink
after being diluted with ethyl acetate are retained. Therefore, a
contact angle with respect to each medium has been examined by
trial and error, and thus, it has been found that in the dioxazine
pigment prepared such that the contact angle is in the range
described above, "the affinity of the dioxazine pigment with
respect to ethyl acetate and ethanol", which is the estimation
mechanism described above, is suitable, and excellent fluidity can
be maintained.
[0023] The contact angle was measured by the infiltration rate
method, as follows. Herein, a numerical value of the contact angle
is obtained by the following method. An automatic surface
tensiometer Processor Tensiometer K12 (manufactured byKRUSS GmbH)
was used. 1.5 g of a dioxazine pigment was filled in a measurement
holder, a measurement liquid was infiltrated from the lower portion
of the holder, and a wetting rate was measured as an option for
measuring a powder wetting rate of the automatic surface
tensiometer. First, a wetting rate of n-hexane was measured, an
infiltration contact angle was assumed as 0.degree., and a filling
constant was measured. Each dioxazine pigment was standardized on
the basis of the measured filling constant such that a filling
state thereof was the same. Subsequently, a wetting rate of each of
water and 1-bromonaphthalene was measured, and the contact angle of
the dioxazine pigment with respect to each of water and
1-bromonaphthalene was calculated by Washburn equation.
[0024] Examples of another method of measuring a contact angle of a
powder such as a dioxazine pigment include a droplet method. The
droplet method is a method in which a powder is subjected to
tableting by using a tablet molding machine, a measurement solvent
is dropped onto the surface of a sample in the shape of a flat
plate, and a contact angle between the sample and the solvent is
measured. However, the contact angle is affected by concavities and
convexities of the sample in the shape of a tablet, and thus, in
the measurement of the contact angle of the powder according to the
droplet method, an error is comparatively large. In addition, the
viscosity of most organic solvents is small, and thus, a liquid
droplet of the organic solvent on the tablet is in a flat shape,
and a contact angle is small, and therefore, a difference in the
contact angles between the samples occurs. Such disadvantages of
the droplet method can be solved by the measurement of the contact
angle according to the infiltration rate method described above.
Note that, from the relationship of the error, and the like, the
contact angle according to the infiltration rate method, and the
contact angle according to the droplet method are not necessarily
coincident with each other.
[0025] Specifically, it is preferable that the dioxazine pigment
exhibiting physical properties described above (the specific
contact angle) does not have both a hydrophilic functional group
and a hydrophobic functional group on the surface of the dioxazine
pigment particles. The functional group is not particularly limited
insofar as a contact angle with respect to water and
1-bromonaphthalene satisfies the specific range described above,
and in a case where the dioxazine pigment has at least one hydroxy
group and at least one carbonyl group on the surface of the
dioxazine pigment, the dioxazine pigment exhibits particularly
excellent fluidity at the time of being used in the preparation of
an ink. It is estimated that the hydroxy group contributes to the
improvement of wettability with respect to a hydrophilic solvent
such as ethanol, and the carbonyl group contributes to the
improvement of wettability with respect to a hydrophobic solvent
such as ethyl acetate. In addition, the functional group
contributes to the wetting of the pigment with respect to the
solvent in the dispersion step, and then, mutually interacts with a
binder resin such as NC or PU, in a dispersion stabilization step,
and adsorbs the binder resin in the surface of the pigment
particles, and thus, also contributes to the dispersion
stabilization.
[0026] In general, the organic pigment is particles in which tens
of thousands to millions of pigment molecules are bonded, and the
same applies to the dioxazine pigment. In consideration of the
wettability of the pigment with respect to the solvent, the site of
the pigment particles relevant to the wettability is the outermost
surface of the pigment particles which is directly in contact with
the solvent. Accordingly, it is sufficient that the functional
group exists on the surface of the pigment particles. The
functional group is substituted with the pigment molecules on the
outermost surface of the dioxazine pigment particles. It is
difficult to specify a substitution position of the functional
group in the pigment molecules, and it is estimated that the
substitution is mainly performed on an aromatic ring. At this time,
the hydrophilic functional group and the hydrophobic functional
group may exist in one pigment molecules, or a pigment molecule
having a hydrophilic functional group and a pigment molecule having
a hydrophobic functional group may separately exist on the surface
of the pigment particles.
[0027] Here, examples of the hydrophilic functional group include a
hydroxy group or an amino group, a sulfo group, a thiol group, a
carboxy group, or salts thereof, and the like.
[0028] In addition, examples of the hydrophobic functional group
include a carbonyl group in which carbon atoms on the dioxazine
pigment particles are bonded with an oxygen atom through a double
bond, a functional group having other carbonyl groups, and
specifically, a ketone group, an ester bond, an amide bond, a
urethane bond, and the like.
[0029] <Production Method>
[0030] Here, an example of a method of preparing the dioxazine
pigment in which the contact angle with respect to water according
to the infiltration rate method is in a range of 30.degree. to
75.degree., and the contact angle with respect to
1-bromonaphthalene according to the infiltration rate method is in
a range of 30.degree. to 75.degree. will be described. However, the
idea of the present invention is as described above, and any method
may be adopted insofar as the dioxazine pigment can be prepared
such that the contact angle is in the numerical range described
above.
[0031] An example of a method of simply obtaining the dioxazine
pigment of the present invention will be described below, but the
present invention is not limited thereto. The dioxazine pigment of
the present invention is obtained through a pigment slurry
producing step of adding a dioxazine pigment that is a raw material
into a solvent, of performing stirring, and of obtaining a pigment
slurry, a pigment surface treatment step of adding an iron salt and
hydrogen peroxide into the pigment slurry, of performing stirring,
and of treating the surface of the pigment, and a step of filtering
a reaction liquid, and of drying and pulverizing a filter
product.
[0032] Examples of the dioxazine pigment that is the raw material
include C.I. Pigment Violet 23, C.I. Pigment Violet 37, C.I.
Pigment Blue 80, and the like. In particular, C.I. Pigment Violet
23 having high color strength and excellent weather resistance is
industrially preferable. A commercially available dioxazine pigment
or a dioxazine pigment that is produced by a known conventional
method can be used as the dioxazine pigment that is the raw
material, and for example, a method described in High Performance
Pigments publishedbyWiley-VCHVerlag-GmbH (2002), Page 186 can be
used as the known conventional method. The dioxazine pigment that
is the raw material may be a dioxazine pigment without any
treatment, or may be a dioxazine pigment in which the surface of
pigment particles is treated with a pigment derivative such as a
dioxazine pigment sulfonic acid derivative, an amino
group-containing dioxazine pigment derivative, and a phthalimide
methyl group-containing dioxazine pigment derivative,
macromolecules such as a dispersant, a surfactant, rosin, or the
like. In addition, other surface treatments of pigment particles
may be performed with the pigment derivative such as the dioxazine
pigment sulfonic acid derivative, the amino group-containing
dioxazine pigment derivative, and the phthalimide methyl
group-containing dioxazine pigment derivative, the macromolecules
such as the dispersant, the surfactant, the rosin, and the like,
after the pigment surface treatment step.
[0033] As the dioxazine pigment that is the raw material, a
dioxazine pigment having a pigment particle diameter and a particle
shape that are adjusted through a pigmentation step may be used, or
a dioxazine pigment crude having a pigment particle diameter and a
particle shape that are not adjusted may be used, and the pigment
forming step may be performed after the pigment surface treatment
step. For example, as the pigment forming step, one of an acid
paste method, an acid slurry method, a dry milling method, a
solvent method, a solvent milling method, and the like can be
selected or a plurality thereof can be selected by being
combined.
[0034] Water and/or an organic solvent can be used as the solvent,
and methanol, ethanol, n-propanol, i-propanol, and the like can be
used as the organic solvent. In particular, water is preferable
from the viewpoint of economic efficiency. In addition, water may
be pure water or may be industrial water, and a buffer solution
such as an acetic acid buffer solution, a phosphoric acid buffer
solution, a citric acid buffer solution, a citric acid-phosphoric
acid buffer solution, a boric acid buffer solution, and a tartaric
acid buffer solution may be used.
[0035] It is preferable that the added amount of the dioxazine
pigment that is the raw material is 1 part by mass to 30 parts by
mass with respect to 100 parts by mass of the solvent, and when the
added amount is small, productivity is low, and when the added
amount is large, the pigment slurry has a high viscosity, and
excessive energy is required for stirring, and thus, the added
amount of the dioxazine pigment is more preferably 2 parts by mass
to 20 parts by mass, and is particularly preferably 3 parts by mass
to 12 parts by mass, with respect to 100 parts by mass of the
solvent.
[0036] Iron sulfate, iron chloride, iron fluoride, iron bromide,
iron iodide, iron nitrate, iron phosphate, iron borate, iron
carbonate, iron acetate, and the like can be used as the iron salt.
Iron sulfate, iron chloride, and iron nitrate are preferable from
the viewpoint of economic efficiency. Divalent iron can be used as
iron. In addition, the iron salt may be an anhydride, or may be a
hydrate.
[0037] It is preferable that a temperature in the pigment slurry
producing step is 0.degree. C. to 100.degree. C. In addition, it is
preferable that a temperature in the pigment surface treatment step
is 0.degree. C. to 100.degree. C., and a reaction rate of a
treatment reaction of the pigment surface is slow at a low
temperature, and the decomposition of hydrogen peroxide is
accelerated at a high temperature, and thus, the temperature in the
pigment surface treatment step is more preferably 10.degree. C. to
90.degree. C., and is particularly preferably 20.degree. C. to
80.degree. C.
[0038] It is preferable that a reaction time in the pigment surface
treatment step is 10 minutes to 2 hours.
[0039] It is preferable that the pH of a treatment liquid in the
pigment surface treatment step is pH 1 to pH 7 since iron ions are
precipitated by alkaline properties.
[0040] It is preferable that 1 mass % to 100 mass % of hydrogen
peroxide is added with respect to the dioxazine pigment that is the
raw material. When the added amount of the hydrogen peroxide is
small, a surface treatment of the dioxazine pigment is
insufficient, and the surface of the pigment particles is finite
and excessive addition is economically disadvantageous, and thus,
the added amount of the hydrogen peroxide is more preferably 3 mass
% to 90 mass %, and is particularly preferably 6 mass % to 80 mass
%.
[0041] It is preferable that 1 mass % to 30 mass % of the iron salt
is added with respect to the dioxazine pigment that is the raw
material. The iron salt functions as a catalyst of a surface
treatment reaction of the pigment, and thus, when the added amount
of the iron salt is small, a reaction rate of the surface treatment
reaction is slow, and excessive addition accelerates the
decomposition of hydrogen peroxide and is economically
disadvantageous, and therefore, it is preferable that the added
amount of the iron salt is 2 mass % to 15 mass %.
[0042] The iron salt and hydrogen peroxide may be simultaneously
added or separately added to the pigment slurry. In a case where
the iron salt and hydrogen peroxide are simultaneously added,
hydrogen peroxide is decomposed when hydrogen peroxide and the iron
salt are mixed in advance mix, and thus, hydrogen peroxide and the
iron salt are mixed in the pigment slurry. In a case where the iron
salt and hydrogen peroxide are separately added, the iron salt may
be added first, or hydrogen peroxide may be added first. In
addition, hydrogen peroxide may be added dropwise or may be added
all at once.
[0043] According to the producing method described above, a hydroxy
group and a carbonyl group are generated on the surface of the
dioxazine pigment particles, and thus, it is possible to obtain a
dioxazine pigment having at least one hydroxy group and at least
one carbonyl group on the surface of the dioxazine pigment, which
is another aspect of the present invention.
[0044] For example, in the producing method described above, it is
possible to more preferably obtain the dioxazine pigment having at
least one hydroxy group and at least one carbonyl group on the
surface of the dioxazine pigment, by preparing treatment conditions
of the surface of the dioxazine pigment particles, such as the type
of solvent, the treatment temperature, and the amount of iron salt
and hydrogen peroxide.
[0045] The dioxazine pigment having at least one hydroxy group and
at least one carbonyl group on the surface of the dioxazine
pigment, which is another aspect of the present invention, is
preferable since the dioxazine pigment exhibits excellent fluidity,
and has the following advantages.
[0046] In a fluidity improving method of the related art, the
fluidity is not sufficiently improved depending on an application,
as described above. In addition, depending on an application, there
is a case where it is difficult to make the fluidity and demand
characteristics other than the fluidity compatible due to the
undesired influence of the derivative treatment for improving the
fluidity. For example, in a dioxazine pigment that is used in a
gravure ink for food packaging, the fluidity and retort resistance
are required to be compatible with each other, but in a case where
the fluidity is improved by the combination of the pigment
derivative, the pigment derivative having dye properties is easily
migrated to a base material (a film), and thus, the retort
resistance tends to decrease.
[0047] As described above, according to the present invention in
which the surface of the dioxazine pigment itself is modified, an
undesired effect due to the derivative treatment for improving the
fluidity, which has been a concern from the related art, can also
be avoided.
[0048] <Mixed Color Stability>
[0049] The present inventors have further pursued the improvement
of dispersion stability performance, and as a result thereof, have
found that the dioxazine pigment of the present invention is also
capable of solving the thickening at the time of being mixed with a
blue ink containing copper phthalocyanine.
[0050] According to the consideration of the present inventors,
such thickening at the time of mixing a violet ink with a blue ink
occurs in the following case. That is, before color mixture, the
binder resin in the ink is adsorbed in each of the dioxazine
pigment and copper phthalocyanine, and thus, dispersion
stabilization is obtained. On the other hand, it is considered that
after the color mixture, binder resin adsorbed in the dioxazine
pigment is adsorbed in copper phthalocyanine having stronger
affinity with respect to the binder resin, and thus, the
aggregation of the dioxazine pigment occurs, and the fluidity
decreases. Here, in the violet ink containing the dioxazine pigment
of the present invention, as described above, the binder resin is
strongly adsorbed in the dioxazine pigment, and dispersion
stability is high. Accordingly, it is estimated that even in a case
where the violet ink is mixed with the blue ink, the dispersion of
the dioxazine pigment and the copper phthalocyanine pigment is
retained, and the fluidity is maintained.
[0051] Copper phthalocyanine is preferable as a color material of
the blue ink, from the viewpoint of a color phase, toughness,
economic efficiency, and the like. In addition, the copper
phthalocyanine may be copper phthalocyanine without any treatment,
or may be copper phthalocyanine in which the surface of pigment
particles is treated with a pigment derivative such as a copper
phthalocyanine sulfonic acid derivative, an amino group-containing
copper phthalocyanine derivative, and a phthalimide methyl
group-containing copper phthalocyanine derivative, macromolecules
such as a dispersant, a surfactant, rosin, or the like. In
addition, the violet ink containing the dioxazine pigment of the
present invention and the blue ink can be mixed in a wide ratio in
order to impart a reddish color to the blue ink or to reproduce
deep purple blue.
[0052] Note that, the dioxazine pigment of the present invention
can be adjusted to be suitable for each application by further
containing an additive, a dispersant, or the like, unless undesired
influence is exerted on the effects of the present invention.
[0053] The dioxazine pigment of the present invention obtained as
described above can be preferably used in any application insofar
as a coloring function is required. For example, the dioxazine
pigment can be used in various known conventional applications such
as a coating material, a printing ink, a colored molded article, a
toner for developing an electrostatic charge image, a color filter
of a liquid crystal display device, and a water-based ink for ink
jet recording.
[0054] The dioxazine pigment of the present invention is capable of
providing a printing ink that is excellent in the initial viscosity
and is also excellent in the storage stability. The printing ink
can be prepared by mixing various known conventional binder resins,
various solvents, various additives, or the like to the dioxazine
pigment of the present invention, in accordance with a preparation
method of the related art. Specifically, it is possible to adjust a
liquid ink by adjusting a base ink for a liquid ink having a high
pigment concentration, and by using various binders, various
solvents, various additives, or the like.
[0055] It is possible to produce the PU ink or the NC ink excellent
in the initial viscosity and the storage stability, from the
dioxazine pigment of the present invention, and the dioxazine
pigment is preferable as an organic pigment composition for a
gravure printing ink or a flexo printing ink. The PU ink contains a
PU resin, a pigment, a solvent, and various additives, and the NC
ink contains an NC resin, a pigment, a solvent, and various
additives. The PU resin is not particularly limited insofar as a
urethane structure is provided in the skeleton, and also includes
polyurethane, polyurethane, polyurea, and the like. Examples of
each of the solvents include an aromatic organic solvent such as
toluene and xylene, a ketone-based solvent such as methyl ethyl
ketone, methyl isobutyl ketone, cyclohexane, 2-heptanone, and
3-heptanone, an ester-based solvent such as ethyl acetate, n-propyl
acetate, isopropyl acetate, isobutyl acetate, propylene glycol
monoethyl ether acetate, and propylene glycol monomethyl ether
acetate, an alcohol-based solvent such as methanol, ethanol,
n-propanol, isopropanol, n-butanol, isobutanol, and t-butanol, a
(poly)alkylene glycol monoalkyl ether-based solvent such as
propylene glycol monoethyl ether, propylene glycol monomethyl
ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl
ether, ethylene glycol mono-n-propyl ether, ethylene glycol
mono-i-propyl ether, diethylene glycol monomethyl ether, diethylene
glycol monoethyl ether, diethylene glycol mono-n-propyl ether, and
diethylene glycol mono-i-propyl ether, a (poly)alkylene glycol
monoalkyl ether acetate-based solvent such as ethylene glycol
monomethyl ether acetate, ethylene glycol monoethyl ether acetate,
diethylene glycol monomethyl ether acetate, and diethylene glycol
monoethyl ether acetate, another ether-based solvent such as
diethylene glycol dimethyl ether and diethylene glycol diethyl
ether, and the like. Note that, the solvents may be independently
used, or two or more types thereof may be used together. a
surfactant such as an anionic surfactant, a nonionic surfactant, a
cationic surfactant, and an amphoteric ionic surfactant, rosins
such as gum rosin, polymerized rosin, disproportionation rosin,
hydrogenerated rosin, maleated rosin, cured rosin, and an alkyd
phthalate resin, a pigment derivative, a dispersant, a wetting
agent, an adhesion adjuvant, a leveling agent, an antifoaming
agent, an antistatic agent, a trapping agent, an antiblocking
agent, a wax component, and the like can be used as various
additives.
[0056] In a case where the dioxazine pigment of the present
invention is used as a printing ink, the printing ink using the
dioxazine pigment of the present invention prepared as described
above can be used by being diluted with ethyl acetate, a
polyurethane-based varnish, or a polyamide-based varnish. In the
preparation of the printing ink, a known conventional method can be
adopted.
[0057] In a case where the dioxazine pigment of the present
invention is a coating material as a colorant, as examples of a
resin that is used as the coating material include various resins
such as an acryl resin, a melamine resin, an epoxy resin, a
polyester resin, a polyurethane resin, a polyamide resin, and a
phenol resin.
[0058] Examples of a solvent that is used in the coating material
include an aromatic-based solvent such as toluene, xylene, or
methoxy benzene, an acetic acid ester-based solvent such as ethyl
acetate, butyl acetate, propylene glycol monomethyl ether acetate,
and propylene glycol monoethyl ether acetate, a propionate-based
solvent such as ethoxy ethyl propionate, an alcohol-based solvent
such as methanol, ethanol, propanol, n-butanol, and isobutanol, an
ether-based solvent such as butyl cellosolve, propylene glycol
monomethyl ether, diethylene glycol ethyl ether, and diethylene
glycol dimethyl ether, a ketone-based solvent such as methyl ethyl
ketone, methyl isobutyl ketone, and cyclohexane, an aliphatic
hydrocarbon-based solvent such as hexane, a nitrogen compound-based
solvent such as N,N-dimethyl formamide, .gamma.-butyrolactam,
N-methyl-2-pyrrolidone, aniline, and pyridine, a lactone-based
solvent such as .gamma.-butyrolactone, carbamate ester such as a
mixture of methyl carbamate and ethyl carbamate of 48:52, water,
and the like. In particular, a polar solvent that is water-soluble,
such as a propionate-based solvent, an alcohol-based solvent, an
ether-based solvent, a ketone-based solvent, a nitrogen
compound-based solvent, a lactone-based solvent, and water, is
suitable as the solvent.
[0059] In addition, in a case where a pigment additive and/or a
pigment composition are dispersed and mixed in a liquid resin, and
a resin composition for a coating material is obtained, general
additives, for example, dispersants, fillers, coating material
adjuvants, desiccants, plasticizers and/or adjuvant pigments can be
used. This is attained by dispersing or mixing the components
independently or collectively such that all of the components are
collected, or by adding all of components at once.
[0060] Examples of a disperser for dispersing the composition
containing the dioxazine pigment prepared in accordance with an
application, as described above, include a known disperser such as
a Disper, a homomixer, a paint conditioner, Scandex, a bead mill,
Attritor, a ball mill, a two-roll mill, a three-roll mill, and a
pressure kneader, but the disperser is not limited thereto. In the
dispersion of the pigment composition, a resin and a solvent are
added and dispersed such that a viscosity is obtained at which
dispersion can be performed in the disperser. A coating material
base having a high concentration after dispersion has a solid
content of 5% to 20%, and is mixed with a resin and a solvent to be
used as the coating material.
[0061] Hereinafter, the present invention will be described in more
detail by using examples and comparative examples. In the following
examples and comparative examples, unless otherwise noted, "%"
indicates "mass %".
[0062] In this example, a dioxazine pigment having at least one
hydroxy group and at least one carbonyl group on each surface of 23
particles of C.I. Pigment Violet was checked by a field desorption
ionization mass spectrometry or a laser desorption ionization mass
spectrometry. The details are as follows.
[0063] [Method According to Field Desorption Ionization Mass
Spectrometry]
[0064] Amass spectrometric spectrum of the dioxazine pigment was
measured by using JMS-T100GC manufactured by JEOL Ltd., in the
field desorption ionization mass spectrometry. 5 mg of a sample was
added to 1.0 mL of tetrahydrofuran not containing dibutyl hydroxy
toluene (manufactured by Wako Pure Chemical Industries), was
suspended with an ultrasound wave, and was used in the
measurement.
[0065] [Measurement Condition]
[0066] Emitter Current: 0 mA to 40 mA [25.6 mA/minute]
[0067] Opposite Electrode: -10000 V
[0068] Measurement Mass Range: m/z=50 to 200
[0069] Measurement Time: 2 minutes
[0070] In the mass spectrometric spectrum obtained by this
condition, a molecular peak at 604 indicates C.I. Pigment Violet 23
having one hydroxy group, and a molecular peak at 618 indicates
C.I. Pigment Violet 23 having two carbonyl groups.
[0071] [Method According to Laser Desorption Ionization Mass
Spectrometry]
[0072] Amass spectrometric spectrum of the dioxazine pigment was
measured by using JMS-S3000 manufactured by JEOL Ltd., in the laser
desorption ionization mass spectrometry. 20 mg of a sample was
added to 10 mL of ethanol (manufactured by Wako Pure Chemical
Industries), was suspended with an ultrasound wave, and was used in
a measurement solution. In addition, separately, 20 mg of sodium
iodide (manufactured by Sigma-Aldrich Co. LLC.) was added to 10 mL
of methanol (manufactured by Wako Pure Chemical Industries), was
suspended with an ultrasound wave, and was used in a cationizing
agent.
[0073] [Measurement Condition 1]
[0074] Measurement Sample: 1 .mu.L of Measurement Solution is
spotted on 384-spot measurement plate, manufactured by Hudson
Surface Technology, Inc., and is dried in air.
[0075] Measurement Mode: Spiral TOF Positive Mode
[0076] Laser Intensity: 45%
[0077] Delay Time: 120 nanosecond
[0078] Detector: 60%
[0079] Trace Count: 200 to 250 shots
[0080] In the mass spectrometric spectrum obtained by this
condition, a molecular peak at 604 indicates C.I. Pigment Violet 23
having one hydroxy group.
[0081] [Measurement Condition 2]
[0082] Measurement Sample: 1 .mu.L of Measurement Solution and 1
.mu.L of cationizing agent are spotted on 384-spot measurement
plate, manufactured by Hudson Surface Technology, Inc., are mixed
on the plate, and are dried in air.
[0083] Measurement Mode: Spiral TOF Positive Mode
[0084] Laser Intensity: 45%
[0085] Delay Time: 120 nanosecond
[0086] Detector: 60%
[0087] Trace Count: 200 to 250 Shots
[0088] In the mass spectrometric spectrum obtained by this
condition, a molecular peak at 641 indicates molecules in which
sodium ions of the cationizing agent are added to C.I. Pigment
Violet 23 having two carbonyl groups.
[0089] In addition, in this example, a contact angle of the
dioxazine pigment with respect to water and 1-bromonaphthalene was
measured by an infiltration rate method. The details are as
follows.
[0090] In the measurement, an automatic surface tensiometer
Processor Tensiometer K12 (manufactured by KRUSS GmbH) was used.
1.5 g of a dioxazine pigment was filled in a measurement holder, a
measurement liquid was infiltrated from the lower portion of the
holder, and a wetting rate was measured as an option for measuring
a powder wetting rate of the automatic surface tensiometer. First,
a wetting rate of n-hexane was measured, an infiltration contact
angle was assumed as 0.degree., and a filling constant was
measured. Each dioxazine pigment was standardized on the basis of
the measured filling constant such that a filling state thereof was
the same. Subsequently, a wetting rate of each of water and
1-bromonaphthalene was measured, and the contact angle of the
dioxazine pigment with respect to each of water and
1-bromonaphthalene was calculated by Washburn equation.
(Example 1) [Synthesis of Dioxazine Pigment (A-1)]
[0091] 171.9 parts of a wet cake of C.I. Pigment Violet 23
(manufactured by DIC Corporation) (60 parts of a pigment) and 828.1
parts of ion exchange water were put into a stainless steel cup of
2 L, and were stirred with a Homodisper 2.5 Type (manufactured by
PRIMIX Corporation) at the number of rotations of 500 rpm for 30
minutes. A slurry of C.I. Pigment Violet 23 was moved to a
stainless steel cup of 5 L, and 2.75 parts of iron (II) sulfate
heptahydrate (manufactured by Wako Pure Chemical Industries) was
added and dissolved while performing stirring with a stainless
steel anchor blade at the number of rotations of 150 rpm.
Subsequently, 12.5 parts of 30% hydrogen peroxide water
(manufactured by Wako Pure Chemical Industries) was added and was
stirred for 30 minutes. Next, the slurry was subjected to Nutsche
filtration, and was washed with 4 L of hot water of 70.degree. C.,
and then, a filter product was subjected to blast drying (at
98.degree. C. for 18 hours) by a blast isothermal drier WFO-500
(manufactured by TOKYO RIKAKIKAI CO., LTD.). A pigment lump that
was obtained was pulverized, and thus, 58 parts of a dioxazine
pigment (A-1) was obtained. The dioxazine pigment (A-1) was
subjected to mass spectrometry by the laser desorption ionization
mass spectrometry, and thus, the molecular peak at 604 was checked
in the measurement condition 1, and the molecular peak at 641 was
checked in the measurement condition 2. A contact angle of the
dioxazine pigment (A-1) with water was 69.4.degree., and a contact
angle of the dioxazine pigment (A-1) with respect to
1-bromonaphthalene was 67.7.degree..
(Example 2) [Synthesis of Dioxazine Pigment (A-2)]
[0092] 58 parts of a dioxazine pigment (A-2) was obtained by the
same operation as that of Example 1, except that the added amount
of 30% hydrogen peroxide water was changed to 25 parts. The
dioxazine pigment (A-2) was subjected to mass spectrometry by the
laser desorption ionization mass spectrometry, and thus, the
molecular peak at 604 was checked in the measurement condition 1,
and the molecular peak at 641 was checked in the measurement
condition 2. A contact angle of the dioxazine pigment (A-2) with
respect to water was 57.2.degree., and a contact angle of the
dioxazine pigment (A-2) with respect to 1-bromonaphthalene was
40.3.degree..
(Example 3) [Synthesis of Dioxazine Pigment (A-3)]
[0093] 59 parts of a dioxazine pigment (A-3) was obtained by the
same operation as that of Example 1, except that the added amount
of 30% hydrogen peroxide water was changed to 50 parts. The
dioxazine pigment (A-3) was subjected to field desorption
ionization mass spectrometry, and thus, the molecular peaks at 604
and 618 were checked. Further, the dioxazine pigment (A-3) was
subjected to mass spectrometry by the laser desorption ionization
mass spectrometry, and thus, the molecular peak at 604 was checked
in the measurement condition 1, and the molecular peak at 641 was
checked in the measurement condition 2. A contact angle of the
dioxazine pigment (A-3) with respect to water was 46.9.degree., and
a contact angle of the dioxazine pigment (A-3) with respect to
1-bromonaphthalene was 45.3.degree..
(Example 4) [Synthesis of Dioxazine Pigment (A-4)]
[0094] 58 parts of a dioxazine pigment (A-4) was obtained by the
same operation as that of Example 1, except that the added amount
of 30% hydrogen peroxide water was changed to 100 parts. The
dioxazine pigment (A-4) was subjected to mass spectrometry by the
laser desorption ionization mass spectrometry, and thus, the
molecular peak at 604 was checked in the measurement condition 1,
and the molecular peak at 641 was checked in the measurement
condition 2. A contact angle of the dioxazine pigment (A-4) with
respect to water was 58.4.degree., and a contact angle of the
dioxazine pigment (A-4) with respect to 1-bromonaphthalene was
37.7.degree..
(Example 5) [Synthesis of Dioxazine Pigment (A-5)]
[0095] 59 parts of a dioxazine pigment (A-5) was obtained by the
same operation as that of Example 1, except that the added amount
of iron (II) sulfate heptahydrate was changed to 11 parts, and the
added amount of 30% hydrogen peroxide water was changed to 200
parts. The dioxazine pigment (A-5) was subjected to mass
spectrometry by the field desorption ionization mass spectrometry,
and thus, the molecular peaks at 604 and 618 were checked. Further,
the dioxazine pigment (A-5) was subjected to mass spectrometry by
the laser desorption ionization mass spectrometry, and thus, the
molecular peak at 604 was checked in the measurement condition 1,
and the molecular peak at 641 was checked in the measurement
condition 2. A contact angle of the dioxazine pigment (A-5) with
respect to water was 57.5.degree., and a contact angle of the
dioxazine pigment (A-5) with respect to 1-bromonaphthalene was
32.9.degree..
(Example 6) [Synthesis of Dioxazine Pigment (A-6)]
[0096] 515.8 parts of a wet cake of C.I. Pigment Violet 23
(manufactured by DIC Corporation) (180 parts of a pigment) and
2484.2 parts of ion exchange water were put into an enamel tank of
10 L, and were stirred with a Homodisper 2.5 Type (manufactured by
PRIMIX Corporation) at the number of rotations of 500 rpm for 30
minutes. Next, a stirring blade was changed to a stainless steel
anchor blade, and 8.25 parts of iron (II) sulfate heptahydrate
(manufactured by Wako Pure Chemical Industries) was added and
dissolved while performing stirring at the number of rotations of
100 rpm. Subsequently, a slurry was heated to 60.degree. C. by
using an electromagnetic heater, and then, 150 parts of 30%
hydrogen peroxide water (manufactured by Wako Pure Chemical
Industries) was dropped for 1 hour, and then, stirring was further
performed for 15 minutes, the slurry was subjected to Nutsche
filtration, and was washed with 12 L of hot water of 70.degree. C.,
and then, a filter product was subjected to blast drying (at
98.degree. C. for 18 hours) by a blast isothermal drier WFO-500
(manufactured by TOKYO RIKAKIKAI CO., LTD.). A pigment lump that
was obtained was pulverized, and thus, 171 parts of a dioxazine
pigment (A-6) was obtained. The dioxazine pigment (A-6) was
subjected to mass spectrometry by the laser desorption ionization
mass spectrometry, and thus, the molecular peak at 604 was checked
in the measurement condition 1, and the molecular peak at 641 was
checked in the measurement condition 2. A contact angle of the
dioxazine pigment (A-6) with respect to water was 71.1.degree., and
a contact angle of the dioxazine pigment (A-6) with respect to
1-bromonaphthalene was 49.4.degree..
(Comparative Example 1) [Synthesis of Dioxazine Pigment (A'-1)]
[0097] 171.9 parts of a wet cake of C.I. Pigment Violet 23
(manufactured by DIC Corporation) (60 parts of a pigment) and 828.1
parts of ion exchange water were put into a stainless steel cup of
2 L, and were stirred with a Disper at the number of rotations of
500 rpm for 30 minutes. A slurry of C.I. Pigment Violet 23 was
subjected to Nutsche filtration, and was washed with 4 L of hot
water of 70.degree. C., and then, a filter product was subjected to
blast drying (at 98.degree. C. for 18 hours) by a blast isothermal
drier WFO-500 (manufactured by TOKYO RIKAKIKAI CO., LTD.). A
pigment lump that was obtained was pulverized, and thus, 59 parts
of a comparative dioxazine pigment (A'-1) was obtained. The
dioxazine pigment (A'-1) was subjected to field desorption
ionization mass spectrometry, but the molecular peaks at 604 and
618 were not observed. In addition, the dioxazine pigment (A'-1)
was subjected to mass spectrometry by the laser desorption
ionization mass spectrometry, but the molecular peaks at 604 and
641 were not observed in the measurement condition 1 and the
measurement condition 2. A contact angle of the dioxazine pigment
(A'-1) with respect to water was 90.0.degree., and a contact angle
of the dioxazine pigment (A'-1) with respect to 1-bromonaphthalene
was 85.6.degree..
(Comparative Example 2) [Synthesis of Dioxazine Pigment (A'-2)]
[0098] 171.9 parts of a wet cake of C.I. Pigment Violet 23
(manufactured by DIC Corporation) (60 parts of a pigment) and 828.1
parts of ion exchange water were put into a glass beaker of 2 L,
and were stirred with a Homodisper 2.5 Type (manufactured by PRIMIX
Corporation) at the number of rotations of 500 rpm for 30 minutes.
Next, a stirring blade was changed to a glass anchor blade, and the
temperature was increased to 70.degree. C. while performing
stirring at the number of rotations of 150 rpm. 4 parts of a
sulfonic acid derivative (manufactured by DIC Corporation) of C.I.
Pigment Violet 23, dissolved in 100 parts of hot water of
70.degree. C., was added to a slurry of C.I. Pigment Violet 23, and
was stirred for 30 minutes. Subsequently, 6 parts of aluminum
sulfate (manufactured by Wako Pure Chemical Industries), dissolved
in 100 parts of hot water of 70.degree. C., was added, and was
stirred for 2 hours. The slurry was subjected to Nutsche
filtration, and a filter product was subjected to blast drying (at
98.degree. C. for 18 hours) by a blast isothermal drier WFO-500
(manufactured by TOKYO RIKAKIKAI CO., LTD.). A pigment lump that
was obtained was pulverized, and thus, 59 parts of a dioxazine
pigment (A'-2) was obtained. The dioxazine pigment (A'-2) was
subjected to mass spectrometry by the laser desorption ionization
mass spectrometry, but the molecular peaks at 604 and 641 were not
observed in the measurement condition 1 and the measurement
condition 2. A contact angle of the dioxazine pigment (A'-2) with
respect to water was 89.9.degree., and a contact angle of the
dioxazine pigment (A'-2) with respect to 1-bromonaphthalene was
48.5.degree.. [0099] [Preparation of Various Inks]
[0100] The evaluation of a polyurethane ink is as follows.
[0101] (Preparation of Polyurethane Ink)
[0102] In each of the dioxazine pigment obtained in Examples 1 to 6
and the comparative dioxazine pigment obtained in Comparative
Examples 1 and 2, 5 parts of the dioxazine pigment, 25 parts of a
polyurethane resin SANPRENE IB-501 (manufactured by Sanyo Chemical
Industries, Ltd.), 13 parts of ethyl acetate (manufactured by Wako
Pure Chemical Industries), 7 parts of isopropyl alcohol
(manufactured by Wako Pure Chemical Industries), and 180 parts of
1/8-inch steel beads (manufactured by Mochiki Steel Ball Bearing
Co., Ltd.) were put into polyethylene wide-mouth bottle of 250 mL,
and were dispersed with a Paint Shaker (manufactured by Toyo Seiki
Seisaku-sho, Ltd.) for 30 minutes. After that, 35 parts of a
polyurethane resin SANPRENE IB-501(manufactured by Sanyo Chemical
Industries, Ltd.), 9.75 parts of ethyl acetate (manufactured by
Wako Pure Chemical Industries), and 5.25 parts of isopropyl alcohol
(manufactured by Wako Pure Chemical Industries) were additionally
put into the wide-mouth bottle, and were dispersed with a Paint
Shaker (manufactured by Toyo Seiki Seisaku-sho, Ltd.) for 5
minutes, and thus, each polyurethane ink was obtained.
[0103] (Measurement of Initial Viscosity of Polyurethane Ink)
[0104] The obtained polyurethane ink was left to stand in a
thermostatic bath of 20.degree. C. for 1 hour or longer, and an
initial viscosity was measured by an R85 Type Viscosimeter RB85L
(manufactured by TOKI SANGYO CO., LTD.) at a rotation rate of 30
rpm. It is excellent as the initial viscosity is low. In Table 1,
evaluation was performed as follows. [0105] Evaluation of Initial
Viscosity of Polyurethane Ink (Viscosity at 30 rpm (Unit:
mPas))
[0106] A: Less than 100
[0107] B: 100 or more and less than 1000
[0108] C: 1000 or more
[0109] (Measurement of Viscosity of Polyurethane Ink after
Stability Test)
[0110] The obtained polyurethane ink was left to stand in a
multiplex safety type drier MSO-45TPH (manufactured by Futaba
Chemical Co., Ltd.) at 50.degree. C. for 7 days, and then, was left
to stand in a thermostatic bath of 20.degree. C. for 1 hour or
longer, and a viscosity after a stability test was measured by an
R85 Type Viscosimeter RB85L (manufactured by TOKI SANGYO CO., LTD.)
at a rotation rate of 30 rpm. It is excellent as the viscosity
after the stability test is low. In Table 1, evaluation was
performed as follows. [0111] Evaluation of Viscosity of
Polyurethane Ink after Stability Test (Viscosity at 30 rpm (Unit:
mPas))
[0112] A: Less than 100
[0113] B: 100 or more and less than 1000
[0114] C: 1000 or more
[0115] (Measurement of Gloss)
[0116] The obtained polyurethane ink was subjected to color
spreading with respect to a PET film Lumirror 50T-60 (manufactured
by PANAC INDUSTRIES, INC.) by a bar coater of No. 6, and the gloss
of a color spreading film at 60.degree. was measured with a
glossimeter GM-268 Plus (manufactured by KONICA MINOLTA JAPAN,
INC.). It is excellent as the gloss is large. In Table 1,
evaluation was performed as follows. [0117] Evaluation of Gloss of
Color Spreading Film at 60.degree.
[0118] A: 85 or more
[0119] B: 80 or more and less than 85
[0120] C: Less than 80
[0121] In each of the obtained polyurethane inks, the evaluation of
the initial viscosity, the viscosity after the stability test, and
the gloss of the color spreading film at 60.degree. is shown in
Table 1.
TABLE-US-00001 TABLE 1 Viscosity after Initial stability Gloss
Dioxazine pigment viscosity test at 60.degree. Example 1 Dioxazine
pigment (A-1) B B B Example 2 Dioxazine pigment (A-2) A A A Example
3 Dioxazine pigment (A-3) A A A Example 4 Dioxazine pigment (A-4) A
A A Example 5 Dioxazine pigment (A-5) A A A Example 6 Dioxazine
pigment (A-6) A A A Comparative Dioxazine pigment C C C Example 1
(A'-1) Comparative Dioxazine pigment B C C Example 2 (A'-2)
[0122] As it is obvious from the comparison between Examples 1 to 6
and Comparative Examples 1 and 2, the polyurethane ink obtained by
using the dioxazine pigment of the present invention has a lower
initial viscosity and a lower viscosity after a stability test than
those of the polyurethane ink obtained by the dioxazine pigment
without any treatment or the dioxazine pigment treated with the
sulfonic acid derivative of C.I. Pigment Violet 23. In addition,
the polyurethane ink obtained by using the dioxazine pigment of the
present invention has excellent performance that the gloss of the
color spreading film at 60.degree. is particularly high.
[0123] [Evaluation in NC Ink]
[0124] (Preparation of NC Varnish)
[0125] 250 parts of an NC resin (Nitrogen: 10.7 to 12.2), 436.5
parts of ethanol (manufactured by Wako Pure Chemical Industries),
and 13.5 parts of ethyl acetate (manufactured by Wako Pure Chemical
Industries) were put into polyethylene wide-mouth bottle of 1 L,
and were dispersed with a Paint Shaker (manufactured by Toyo Seiki
Seisaku-sho, Ltd.) for 2 hours, and thus, an NC varnish was
obtained.
[0126] (Preparation of NC Base Ink)
[0127] In each of the dioxazine pigment A-3 obtained in Example 3
and the dioxazine pigment A'-1 obtained in Comparative Example 1,
22 parts of the dioxazine pigment, 40 parts of the NC varnish, 36.9
parts of ethanol (manufactured by Wako Pure Chemical Industries),
1.1 parts of ethyl acetate (manufactured by Wako Pure Chemical
Industries), and 150 parts of SAZ beads (manufactured by Tokyo
Garasu Kikai Co., Ltd. Zirconia YTZ Ball of 1.25.PHI.) were put
into a glass bottle of 200 mL, and were dispersed with Shaker
Skandex SK550 (manufactured by Fast&Fluid Management B. V.
Company) for 2 hours, and thus, an NC base ink was obtained.
[0128] (Preparation of Ink Diluted with Ethyl Acetate)
[0129] 38.5 parts of the obtained NC base ink and 16.5 parts of
ethyl acetate (manufactured by Wako Pure Chemical Industries) were
put into a polyethylene wide-mouth bottle of 100 mL, and were
dispersed with a Paint Shaker (manufactured by Toyo Seiki
Seisaku-sho, Ltd.) for 10 seconds, and thus, an ink diluted with
ethyl acetate was obtained.
[0130] (Measurement of Viscosity of NC Base Ink after Stability
Test)
[0131] The obtained NC base ink was left to stand at a room
temperature for 24 hours, and then, was left to stand in a
thermostatic bath of 20.degree. C. for 1 hour or longer, and a
viscosity after a stability test was measured by R85 Type
Viscosimeter RB85L (manufactured by TOKI SANGYO CO., LTD.) at 30
rpm. It is excellent as the viscosity after the stability test is
low.
[0132] (Measurement of Viscosity of Ink Diluted with Ethyl
Acetate)
[0133] The obtained ink diluted with ethyl acetate was left to
stand in a thermostatic bath of 20.degree. C. for 1 hour or longer,
and a viscosity was measured by R85 Type Viscosimeter RB85L
(manufactured by TOKI SANGYO CO., LTD.). It is excellent as the
viscosity after being diluted with ethyl acetate is low.
[0134] Evaluation results in the NC ink are collectively shown in
Table 2. A case where the dioxazine pigment (A-3) was used as the
dioxazine pigment was set to Example 7, and a case where the
dioxazine pigment (A'-1) was used as the dioxazine pigment was set
to Comparative Example 3. Note that, the unit of various
viscosities in Table 2 is mPas.
TABLE-US-00002 TABLE 2 Viscosity after Viscosity after stability
being diluted with Dioxazine pigment test ethyl acetate Example 7
Dioxazine pigment (A-3) 3024 2240 Comparative Dioxazine pigment
(A'-1) 3920 10800 Example 3
[0135] As it is obvious from the comparison between Example 7 and
Comparative Example 3, the NC ink obtained by using the dioxazine
pigment of the present invention has a lower viscosity after a
stability test and a lower viscosity after being diluted with ethyl
acetate than those of the NC ink obtained by the dioxazine pigment
without any treatment.
* * * * *