U.S. patent application number 15/025264 was filed with the patent office on 2017-11-09 for ink composition for high-quality/high-definition screen printing, printed matter produced by the screen printing ink composition, and method for producing the printed matter.
The applicant listed for this patent is TEIKOKU PRINTING INKS MFG., CO., LTD). Invention is credited to Tomomi Ogata, Naoto Takada, Takuya Torihata.
Application Number | 20170321072 15/025264 |
Document ID | / |
Family ID | 56542782 |
Filed Date | 2017-11-09 |
United States Patent
Application |
20170321072 |
Kind Code |
A1 |
Ogata; Tomomi ; et
al. |
November 9, 2017 |
Ink Composition for High-Quality/High-Definition Screen Printing,
Printed Matter Produced by the Screen Printing Ink Composition, and
Method for Producing the Printed Matter
Abstract
An ink composition for high-quality/high-definition screen
printing that, when producing printed matter by screen printing on
an object to be printed using a 360-mesh screen printing plate
formed by a high-strength, non-deforming stainless steel mesh with
a filament diameter of 25 .mu.m, produces printed matter with a
printed image edge spreading width of no more than 10 .mu.m from
the image design dimensions of the printing plate, the ink
composition for screen printing containing a solvent with a boiling
point of 170.degree. C. or higher at 70 wt % or greater of the
total solvent, and a prepolymer or polymer with a weight-average
molecular weight of 2000 or greater at 2 wt % or greater with
respect to the total ink composition, and having a viscosity of 30
to 180 Pas as measured with a BH-type rotating viscosimeter at
25.degree. C., and a thixotropic index of 2.0 to 8.0.
Inventors: |
Ogata; Tomomi; (Tokyo,
JP) ; Torihata; Takuya; (Japan, JP) ; Takada;
Naoto; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TEIKOKU PRINTING INKS MFG., CO., LTD) |
Tokyo |
|
JP |
|
|
Family ID: |
56542782 |
Appl. No.: |
15/025264 |
Filed: |
May 28, 2015 |
PCT Filed: |
May 28, 2015 |
PCT NO: |
PCT/JP2015/065426 |
371 Date: |
March 26, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C09D 11/104 20130101;
C09D 11/106 20130101; C09D 11/02 20130101; C09D 11/03 20130101;
C09D 11/107 20130101; C09D 11/10 20130101; C09D 11/00 20130101;
C09D 11/033 20130101; B41M 1/34 20130101; B41M 1/26 20130101; B41M
1/30 20130101; B41M 1/12 20130101; C09D 11/102 20130101; C09D 11/52
20130101; B41F 15/00 20130101; C09D 11/037 20130101 |
International
Class: |
C09D 11/037 20140101
C09D011/037; C09D 11/107 20140101 C09D011/107; C09D 11/104 20140101
C09D011/104; B41M 1/12 20060101 B41M001/12; C09D 11/102 20140101
C09D011/102; C09D 11/03 20140101 C09D011/03; C09D 11/52 20140101
C09D011/52; C09D 11/106 20140101 C09D011/106 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 27, 2015 |
JP |
2015-013207 |
Claims
1-9. (canceled)
10. An ink composition for high-quality/high-definition screen
printing, comprising: an ink composition having a measured flow
radius value of 14.0 to 19.0 mm after 1 minute from a start of
measurement by a flow property measuring method using a spread
meter at 25.degree. C. according to JIS K5701-1:2000, and wherein
the ink composition satisfies "F60"-"F45".ltoreq.1.0 mm, where
"F60" is defined as the measured flow radius value after 1 minute
and "F45" is defined as the measured flow radius value after 45
seconds from the start of measurement by a flow property measuring
method using the spread meter, the ink composition is one that,
when producing printed matter by screen printing onto an object to
be printed using a 360-mesh screen printing plate formed by a
high-strength, non-deforming stainless steel mesh with a filament
diameter of 25 .mu.m, produces printed matter with a printed image
edge spreading width of no more than 10 .mu.m from image design
dimensions of the printing plate, the ink composition including a
solvent with a boiling point of at least 170.degree. C. at a wt %
of at least 70 wt % of a total of the solvent, and one of a
prepolymer and polymer with a weight-average molecular weight of at
least 2000 at a wt % of at least 2 wt % with respect to a total of
the ink composition, and having a viscosity of 30 to 180 Pas as
measured with a BH-type rotating viscosimeter at 25.degree. C., and
a thixotropic index (TI) of 2.0 to 8.0.
11. The ink composition for screen printing according to claim 10,
wherein the ink composition includes at least one of the following:
a coloring material, an extender pigment a filler, wherein the
coloring material, extender pigment and filler are dispersed in the
ink composition with a mean particle size of no greater than 35
.mu.m.
12. The ink composition for screen printing according to claim 10,
wherein the ink composition is an ink composition for graphic
decorative screen printing.
13. The ink composition for screen printing according to claim 10,
wherein the ink composition is an ink composition for screen
printing to be used for at least one of the following: black
matrix, black stripe, resist pattern, spacer dot formation, and
light guiding panel dot formation.
14. The ink composition for screen printing according to claim 10,
wherein the ink composition includes a filler with a conductive
property, and the filler is dispersed in the ink composition with a
mean particle size of no greater than 10 .mu.m.
15. Printed matter produced by screen printing onto an object to be
printed using the ink composition for screen printing according to
claim 10.
16. A method for producing printed matter, comprising the step of
producing printed matter by the screen printing ink composition for
screen printing onto an object to be printed according to claim 10.
Description
TECHNICAL FIELD
[0001] The present invention relates to an ink composition for
high-quality/high-definition screen printing that allows
high-precision printing of both fine patterns such as fine dot
patterns or fine line patterns, and wide-area solid patterns,
simultaneously in a single step by screen printing, which is a
method widely used for image pattern formation in the field of
graphics and electric and electronic part-related fields, as well
as to printed matter produced by the screen printing ink
composition and to a method for producing the printed matter.
BACKGROUND ART
[0002] In recent years, for graphic decorative printed matter such
as vehicle meter and household electrical appliance labels and
designs on tablet device frames and enclosures, demands are
increasing for more convenient and low-cost production of printed
matter with greater diversity of design and increasingly high
definition, having both fine patterns (for example, dot patterns
with diameters of about 100 .mu.m, or fine line patterns), and
wide-area solid patterns. There is also a demand for higher quality
and higher definition of the visibility of printed images that
comprise both fine patterns and solid patterns, by improving the
sharpness of the image edge sections in solid patterns while also
obtaining a satisfactory leveling property. Moreover, in the fields
of conductive circuit printing or black matrix printing, for
electric and electronic parts, there is a demand for obtaining a
high degree of definition that provides sharpness to the printed
images without bleeding or spreading, in addition to stable
printing of fine lines, and there is a desire to be able to
accomplish high definition printing with satisfactory visibility in
a single step regardless of the size of the printed area, for cost
reduction.
[0003] In conventional screen printing, when printing a dot pattern
or fine line pattern of approximately 100 .mu.m, printing is
usually performed using a high-viscosity screen printing ink of
about 10 to 200 Pas, with a reduced flow property, but printing of
solid patterns with such high-viscosity screen printing inks cannot
avoid creation of leveling defects or printing abnormalities in the
solid patterns due to the poor flow property, and as a result the
visibility of the printed matter is impaired. Furthermore, when a
low-viscosity screen printing ink of several Pas is used for
satisfactory printing of solid patterns, it has been impossible to
avoid spreading of ink that may exceed about 50 to 100 .mu.m at the
solid pattern image edge sections, or enlargement, spreading or
bleeding of fine patterns, that impair the visibility of the
printed matter, and therefore screen printing of fine patterns and
solid patterns is performed separately with different inks suitably
prepared for each, and it has been difficult to produce printed
matter comprising both fine patterns and solid patterns in a single
step of screen printing.
[0004] Ink jet printing, on the other hand, is considered to allow
high-precision printing of printed matter comprising both fine
patterns and solid patterns in a single step, and many attempts
have been made to accomplish high-quality, high-definition printing
by ink jet printing, however, since ink jet printing involves
spraying ink droplets from a head nozzle with a diameter of about
30 .mu.m, which spread out to about 50 .mu.m at minimum when the
droplets impact with the object being printed, it has been the case
that such printing lacks sharp linearity especially at image edge
sections.
[0005] Offset printing is another printing system that allows
creation of high-quality, high-definition printed matter, however,
since the structure of the printing plate is mesh-like, resulting
in the printed images that are aggregated prints of halftone dots,
it has been impossible to avoid a lack of sharp linearity at image
edge sections, similar to ink jet printing, while the printing film
thickness is also thin at about 1 to 2 .mu.m, and when compared to
screen printed matter, it is inferior in terms of high film
thickness, high durability, high weather resistance and high
chemical resistance, as well as firm adhesion to various objects to
be printed and versatile functionality, such that it is unsuitable
for creation of printed matter that requires durability and
functionality, such as vehicle meter and household electrical
appliance labels, designs on tablet device frames and enclosures,
circuit printing for electric and electronic parts, and light
modulated black matrices.
[0006] Prior Patent Document 1 (Japanese Unexamined Patent
Application Publication No. 2010-047716) discloses a conductive ink
composition and conductive coating film for screen printing that
can form high-definition patterns, but techniques relating to the
flow property of ink for printing with both fine patterns and solid
patterns have not been pursued, and therefore while fine patterns
can be obtained with satisfactory printing precision, in the case
of solid patterns the leveling property is poor and printing
abnormalities are generated. Furthermore, the technical scope of
Prior Patent Document 1 relates only to printing of fine patterns
with the conductive ink composition.
[0007] In addition, Prior Patent Document 2 (Japanese Unexamined
Patent Application Publication No. 2003-238876) and Prior Patent
Document 3 (Japanese Unexamined Patent Application Publication No.
2003-294930) disclose ink compositions for screen printing that
allow formation of high-definition patterns, but as with Prior
Patent Document 1, the disclosures are of techniques for highly
precise printing of fine patterns but not of technology relating to
ink compositions for simultaneous printing of solid patterns in a
single step.
CITATION LIST
Patent Document
[Prior Patent Document 1] Japanese Unexamined Patent Application
Publication No. 2010-047716
[Prior Patent Document 2] Japanese Unexamined Patent Application
Publication No. 2003-238876
[Prior Patent Document 3] Japanese Unexamined Patent Application
Publication No. 2003-294930
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0008] The present invention has been accomplished in light of the
problems described above, and it relates to an ink composition for
high-quality/high-definition screen printing that allows printing
of both fine patterns such as fine dot patterns or fine line
patterns, and wide-area solid patterns, simultaneously in a single
step by screen printing, which has been considered impossible to
achieve by conventional screen printing, as well as to printed
matter produced by the screen printing ink composition and to a
method for producing the printed matter.
Means for Solving the Problems
[0009] The invention relates to an ink composition for screen
printing, which is an ink composition for
high-quality/high-definition screen printing that, when producing
printed matter by screen printing onto an object to be printed
using a 360-mesh screen printing plate formed by a high-strength,
non-deforming stainless steel mesh with a filament diameter of 25
.mu.m, produces printed matter with a printed image edge spreading
width of no more than 10 .mu.m from the image design dimensions of
the printing plate, the ink composition for screen printing
containing a solvent with a boiling point of 170.degree. C. or
higher at 70 wt % or greater of the total solvent, and a prepolymer
or polymer with a weight-average molecular weight of 2000 or
greater at 2 wt % or greater with respect to the total ink
composition, and having a viscosity of 30 to 180 Pas as measured
with a BH-type rotating viscosimeter at 25.degree. C., and a
thixotropic index of 2.0 to 8.0.
Effect of the Invention
[0010] With the ink composition for screen printing of the
invention, it has become possible to print fine patterns and
large-area solid patterns with high-quality and high-definition by
screen printing, with a single screen printing step.
BEST MODE FOR CARRYING OUT THE INVENTION
[0011] As is mentioned above, the invention relates to an ink
composition for screen printing, which is an ink composition for
high-quality/high-definition screen printing that, when producing
printed matter by screen printing on an object to be printed using
a 360-mesh screen printing plate formed by a high-strength,
non-deforming stainless steel mesh with a filament diameter of 25
.mu.m, produces printed matter with a printed image edge spreading
width of no more than 10 .mu.m from the image design dimensions of
the printing plate, the ink composition for screen printing
containing a solvent with a boiling point of 170.degree. C. or
higher at 70 wt % or greater of the total solvent, and a prepolymer
or polymer with a weight-average molecular weight of 2000 or
greater at 2 wt % or greater with respect to the total ink
composition, and having a viscosity of 30 to 180 Pas as measured
with a BH-type rotating viscosimeter at 25.degree. C., and a
thixotropic index of 2.0 to 8.0.
[0012] The invention further relates to an ink composition for
screen printing, wherein the ink composition has a measured flow
radius value of 14.0 to 19.0 mm after 1 minute from the start of
measurement by a flow property measuring method using a spread
meter at 25.degree. C. according to JIS K5701-1:2000.
[0013] It further relates to an ink composition for screen
printing, wherein the ink composition satisfies
"F60"-"F45".ltoreq.1.0 mm, where "F60" is defined as the measured
flow radius value after 1 minute and "F45" is defined as the
measured flow radius value after 45 seconds from the start of
measurement by the flow property measuring method using the spread
meter.
[0014] The invention still further relates to an ink composition
for screen printing, wherein the ink composition contains at least
one coloring material, extender pigment and filler, either of one
type or multiple types, or a combination thereof, the coloring
material, extender pigment and filler are dispersed in the ink
composition with a mean particle size of no greater than 35
.mu.m.
[0015] The invention still further relates to an ink composition
for screen printing that is an ink composition for graphic
decorative screen printing.
[0016] The invention still further relates to an ink composition
for screen printing that is an ink composition for screen printing
to be used for black matrix, black stripe, resist pattern, spacer
or light guiding panel dot formation.
[0017] It still further relates to an ink composition for screen
printing, the ink composition including a filler, the filler having
conductivity, and the filler being dispersed in the ink composition
with a mean particle size of no greater than 10 .mu.m.
[0018] The invention still further relates to printed matter
produced by the screen printing ink composition for screen printing
onto an object to be printed.
[0019] The invention still further relates to a method for
producing printed matter, wherein printed matter is produced by the
screen printing ink composition for screen printing onto an object
to be printed.
[0020] The ink composition for screen printing of the invention
contains a solvent with a boiling point of 170.degree. C. or
higher, at 70 wt % or greater of the total solvent. If the solvent
with a boiling point of 170.degree. C. or higher is not present in
an amount of at least 70% of the total solvent, rapid ink drying on
the screen printing plate will cause clogging due to an ink-dried
coating on the screen printing plate, and defects will be produced
in the fine pattern or at the solid image edge sections, making it
impossible to obtain a high-definition printed matter with high
quality.
[0021] There are no particular restrictions on solvents other than
the solvent with a boiling point of 170.degree. C. or higher to be
present in the ink composition for screen printing of the
invention, but in order to attenuate the evaporation rate of the
solvent with a boiling point of 170.degree. C. or higher, by
azeotropic evaporation, and obtain more satisfactory stability of
the screen printing ink composition on the screen plate, it is
preferred to use solvents whose boiling points are not below
100.degree. C.
[0022] The solvent with a boiling point of 170.degree. C. or higher
according to the invention may be an organic solvent such as
isophorone, a dibasic acid ester (DBE), 3-methoxy-3-methylbutanol,
3-methoxy-3-methylbutyl acetate, ethyleneglycol monobutyl ether
acetate, coal tar naphtha with a boiling point of 170.degree. C. or
higher, diethyleneglycol monoethyl ether (acetate),
diethyleneglycol monobutyl ether (acetate) or triethyleneglycol
monobutyl ether (acetate), and/or a (meth)acrylate monomer, vinyl
ether monomer or amide monomer that hardens under activating energy
rays.
[0023] Preferred examples of solvents whose boiling point is not
below 100.degree. C., according to the invention, include xylene,
cyclohexanone, coal tar naphtha with a boiling point of 160 to
170.degree. C., mineral spirits with a boiling point of 150 to
170.degree. C., 1-methoxy-2-propanol, 1-methoxypropyl-2-acetate and
diacetone alcohol.
[0024] The solvent of the invention needs only contain 70 wt % or
greater of a solvent with a boiling point of 170.degree. C. or
higher among the total solvent, but in order to further stabilize
the screen printing properties for fine patterns, the boiling point
of the solvent is preferably 190.degree. C. or higher.
[0025] However, since using mineral oil or vegetable oil with a
boiling point exceeding 250.degree. C. as the solvent results in a
poor drying property of the printed coating film, when a solvent
having a boiling point of higher than 250.degree. C. is used, it is
preferably used at no more than 5 wt % of the total solvent
amount.
[0026] In addition, the ink composition for screen printing of the
invention contains at least a prepolymer or polymer with a
weight-average molecular weight of 2000 or greater, as a binder
resin, at 2 wt % or greater with respect to the total ink
composition.
[0027] If the weight-average molecular weight of the prepolymer or
polymer is less than 2000, problems such as weak adhesion or
durability of the printed coating film onto objects to be printed
will result, while if the weight-average molecular weight exceeds
200000, the solubility in solvents will be poor and a greater
amount of time and labor will be necessary for production of the
ink composition. Therefore, a more preferred weight-average
molecular weight range is about 4000 to 100000.
[0028] If the content of the prepolymer or polymer with a
weight-average molecular weight of 2000 or greater is less than 2
wt % with respect to the total ink composition, this may lead to
reduced adhesion and durability of the printed coating film onto
objects to be printed, and undesirable results such as leveling
defects and pinhole generation in the printed coating film, due to
poor dispersion of the coloring agent. If it exceeds 70 wt %, on
the other hand, the viscosity may become too high making it
difficult to accomplish uniform screen printing, or the mixing
ratio of the solvent with a boiling point of 170.degree. C. or
higher will be lower, tending to result in easier drying of the ink
on the screen printing plate and tending to result in clogging of
fine patterns. Therefore, a more preferred content is about 5 to 70
wt % of the total ink composition, an even more preferred range
being 10 to 70 wt % and the most preferred range being 15 to 60 wt
%, as preferred ranges even for use as an ink for graphic
decorative screen printing.
[0029] The prepolymer or polymer of the invention has a
weight-average molecular weight of 2000 or greater, and there are
no particular restrictions on the type or mixing ratio as long as
the content is 2 wt % or greater with respect to the total ink
composition and up to a content that allows dissolution in the
solvent in the ink composition, although it is desirable to avoid
highly hazardous harmful substances, such as substances that are
strongly toxic for humans or organisms or substances that create a
high environmental load.
[0030] Examples for the prepolymer include urethane acrylates,
polyester acrylates and epoxy acrylates that harden by activating
energy rays, such polymers including polyester resins, various
types of modified polyester resins such as urethane-modified
polyester resins, epoxy-modified polyester resins and
acryl-modified polyester resins, vinyl chloride-vinyl acetate
copolymer resins, butyral resins, polyether-urethane resins,
polyester-urethane resins, polycarbonate-urethane resins, epoxy
resins, phenol resins, acrylic resins, polyamide resins,
polyamideimide resins, polyolefin resins, chlorinated polyolefin
resins, chlorinated rubber, melamine resins, urea resins, modified
cellulose resins such as ethyl cellulose resin, nitrocellulose
resins, cellulose acetate butyrate (CAB) and cellulose acetate
propionate (CAP), rosin resins, maleic acid resins, natural resins
and alkyd resins, any of which may be used alone or in
combination.
[0031] The ink composition for screen printing of the invention
also has a viscosity of 30 to 180 Pas, and more preferably 50 to
120 Pas, as measured by a BH-type rotating viscosimeter. If the
viscosity is lower than 30 Pas, bleeding and spreading may occur in
the fine patterns and solid image edge sections making it
impossible to obtain a high-quality, high-definition printed image,
while if the viscosity is higher than 180 Pas, the ink may not be
uniform on the screen printing plate, or parting of the ink from
the screen printing plate may be poor, producing abnormalities in
solid images or creating defects in fine patterns or image edge
sections.
[0032] Also, the ink composition for screen printing of the
invention has a thixotropic index (TI value) of 2.0 to 8.0, the TI
value being more preferably 4.0 to 7.0. If the TI value is less
than 2.0, the ink flow property will increase, resulting in
spreading in printed images with the passage of time after printing
even if the viscosity is 180 Pas, such that fine patterns or image
edge sections may become enlarged. If the TI value exceeds 8.0, the
degree of protrusion of the ink from the screen printing plate will
be excessive even if the viscosity is 30 Pas, such that bleeding
may occur in fine patterns and at image edge sections making it
impossible to obtain sharp printed images, or the flow property
with time may be impaired, resulting in poor leveling especially on
solid images.
[0033] The "TI value," for the purpose of the invention, is the
ratio of the viscosity value with 2 rotations and the viscosity
value with 20 rotations of the BH-type rotating viscosimeter at
25.degree. C., or in other words the value: [viscosity with 2
rotations of BH-type rotating viscosimeter/viscosity with 20
rotations of BH-type rotating viscosimeter].
[0034] Furthermore, according to the invention, preferably the ink
composition has a measured flow radius value (hereinafter referred
to as "flow value") of 14.0 to 19.0 mm after 1 minute from the
start of measurement by a flow property measuring method using a
spread meter at 25.degree. C. according to JIS K5701-1:2000. It is
more preferably 15.0 to 18.0 mm. If the flow value is less than
14.0 mm, the ink will protrude from the screen printing plate with
greater difficulty, requiring modifications such as increased
printing pressure of the squeegee during screen printing, while if
the flow value is greater than 19.0 mm, the degree of ink
protrusion from the screen printing plate will tend to be greater,
requiring modifications such as lowering the printing pressure of
the squeegee during screen printing.
[0035] Moreover, the flow value represents the radius value of ink
that has flowed after 1 minute from the start of measurement with a
spread meter as is mentioned above (hereinafter defined as "F60"),
but more preferably, if the radius value after 45 seconds from the
start of measurement with a spread meter is defined as "F45," then
the ink composition is within the above-mentioned flow value range
and "F60"-"F45".ltoreq.1.0 mm, to obtain stable high-quality,
high-definition printed images. This is so that the ink will have a
suitable flow property during printing, and so that after printing,
the flow property will be such as to minimize large spread of
spreading with the passage of time.
[0036] The ink composition of the invention is an ink composition
for high-quality/high-definition screen printing that at least,
when printed matter is created by screen printing onto an object to
be printed using a 360 mesh screen printing plate made with a
high-strength, non-deforming stainless steel mesh having a filament
diameter of 25 .mu.m, can produce printed matter with a printed
image edge spreading width of no more than 10 .mu.m from the image
design dimensions of the printing plate. If the printed image edge
spreading width exceeds 10 .mu.m, enlarged sections of the printed
image with respect to the printing plate image design will be
visibly apparent and the printed image will become visibly blurred,
so that it may no longer be considered high-quality,
high-definition decorative printing.
[0037] As is mentioned above, the ink composition for
high-quality/high-definition screen printing can be prepared by
containing at least a solvent with a boiling point of 170.degree.
C. or higher at 70 wt % or greater of the total solvent, containing
at least a prepolymer or polymer with a weight-average molecular
weight of 2000 or greater at 2 wt % or greater with respect to the
total ink composition, and having at least a viscosity of 30 to 180
Pas as measured with a BH-type rotating viscosimeter at 25.degree.
C. and at least a thixotropic index of 2.0 to 8.0.
[0038] In addition, if the ink composition for
high-quality/high-definition screen printing satisfies the
"preferred conditions and/or desirable conditions" mentioned above
and/or below, its production will be further facilitated and the
high-quality/high-definition quality as printed matter may be
improved.
[0039] Here, when the term "zero" .mu.m is used for the printed
image edge spreading width, it means complete absence of spreading
of the printed ink and printing as prescribed by the image design
on the printing plate, but since the printing plate exists in a
state with a knitted screen mesh, even in cases where no spreading
of the ink is present after printing there can be an effect of the
presence of the screen mesh, tending to create minute chipping or
jaggedness at the printed image edge sections. Therefore, the
spreading width for decorative printing images is preferably 2 to
10 .mu.m and more preferably 3 to 8 .mu.m.
[0040] Preferred examples for the screen mesh, screen printing
plate and screen printing conditions will now be described.
[0041] The 360 mesh screen mesh made of a high-strength,
non-deforming stainless steel mesh may be HS-D360 by Asada Mesh
Co., Ltd. (mesh filament diameter: 25 .mu.m.phi., calendered mesh
thickness: 29 .mu.m, open area ratio: 42%, strength index: 2.56 as
indicated by Asada Mesh Co., Ltd.)
[0042] The printing plate is preferably a stainless steel/stainless
steel combination plate, with an emulsion thickness of 7 to 20
.mu.m using an appropriate commercially available photosensitive
emulsion, and further flat-processed on the emulsion surface.
[0043] The screen printing conditions may be, as a preferred
example, a squeegee with a 60 to 90 degree hardness, a clearance of
3 to 7 mm, pressing with a squeegee printing pressure of 1.5 to 2.0
mm, a squeegee angle of 50 to 80 degrees, a squeegee speed of 80 to
300 mm/sec and pressing with a scraper pressure of 1.0 to 2.0
mm.
[0044] Here, it is an essential condition for the ink composition
for screen printing of the invention that, at least for printed
matter screen printed using a 360 mesh screen printing plate made
of a high-strength, non-deforming stainless steel mesh with a
filament diameter of 25 .mu.m, it can produce printed matter with a
printed image edge spreading width of no more than 10 .mu.m from
the image design dimensions of the printing plate, and therefore
even when printed using a screen printing plate made of another
type of screen mesh, if the ink composition for screen printing
conforms to the necessary conditions of the invention, the ink
composition for screen printing is within the technical scope of
the invention.
[0045] Naturally, when using a screen printing plate made of a
high-strength, non-deforming stainless steel mesh that exceeds 360
mesh (for example, 500 mesh, 640 mesh or 840 mesh), spreading of
the printed image edges will be even further reduced and the
printed image edge sections will be sharper.
[0046] Furthermore, when the ink composition for screen printing of
the invention contains at least one coloring material, extender
pigment or filler, either of one type or multiple types, or a
combination thereof, the coloring material, extender pigment and
filler is preferably dispersed in the ink composition with a mean
particle size of no greater than 35 .mu.m. When a coloring
material, extender pigment or filler with a mean particle size
exceeding 35 .mu.m after dispersion is present, clogging of the
mesh spacings of the 360 mesh screen printing plate may occur,
potentially creating chipping and pinholes in the printed
image.
[0047] There are no particular restrictions on the method for
dispersing the coloring material, extender pigment and filler in
the ink composition for screen printing of the invention, and
examples include dispersion using a blade-stirred disperser, bead
disperser or triple roll disperser.
[0048] The coloring agent, extender pigment and filler are not
particularly restricted, and examples of coloring agents include
azo pigments, disazo pigments, bisazo pigments, phthalocyanine
pigments, anthraquinone-based pigments, isoindoline pigments,
dioxazine pigments, quinacridone pigments, perylene-based pigments,
carbon black pigments, lake black pigments, perylene black
pigments, aniline black pigments, iron oxide pigments, titanium
pigments, zinc sulfide pigments and various chromatic color dyes,
any one of which or two or more of which may be used, such coloring
materials being preferably used in a mixing ratio of no greater
than 95 wt % with respect to the ink composition. The amount is
preferably no greater than 50 wt %.
[0049] Examples of extender pigments include (fine particulate)
silica, talc, calcium carbonate, magnesium carbonate, bentonite,
sedimentary barium sulfate, zinc oxide and alumina, any one of
which or two or more in combination may be used, such extender
pigments being preferably used in a mixing ratio of no greater than
30 wt % with respect to the ink composition.
[0050] Examples of fillers include resin beads, metallic particles,
metal powder, metal oxide powder, graphite, pearl pigment,
fluorescent pigments, wax particles and protein powder. Also
included are functional materials, such as ultraviolet absorbing
materials, antimicrobial materials, heat absorbing materials,
refractive index-modifying materials, slidability-imparting
materials, slidability-preventing materials, phosphorescencent
materials, polarizing materials, anti-reflection materials and
diffusible materials. These may be used alone or in combinations of
multiple types, and such fillers are preferably used in a mixing
ratio of no greater than 95 wt %, more preferably no greater than
50 wt % and even more preferably no greater than 30 wt %, with
respect to the ink composition.
[0051] When the ink composition is used as an ink for graphic
decorative screen printing, it is possible to produce
high-definition graphic decorative screen printed matter of high
quality, that has not been achievable with conventional screen
printing, namely having excellent precision with excellent
linearity of image edge sections and free of chipping or spreading
in fine dots, and simultaneously exhibiting rich color shade
expression and different types of functionality.
[0052] Furthermore, an ink composition for screen printing of the
invention containing the above-mentioned coloring agents, extender
pigments and fillers is not limited to such graphic decorative
screen printed matter, and can be used to produce high-definition
screen printed matter even when used for printing onto electric and
electronic parts, such as black matrix or stripe printing for
increasing display visibility, pattern printing for function as a
resist, spacer printing to avoid contact between members, or dot
printing designed for specific area sizes, to ensure uniformity of
luminance in light guiding panels.
[0053] Generally speaking, black inks with a high masking property
are usually used for black matrix or stripe printing, white inks,
black inks, chromatic color inks, transparent inks, dispersive inks
and/or the mixed inks are usually used for resist printing or
spacer printing, and inks containing fillers with light diffusing
functions such as silica or various types of beads, are usually
used for light guiding panel dot printing.
[0054] A filler in the ink composition of the invention may be a
filler with a conductive property. Such conductive fillers include
gold powder, silver powder, copper powder, iron powder, indium
powder and tungsten powder, and/or their oxides or complexes, as
well as graphite, carbon black and the like. In addition, for a
printing ink composition containing such a conductive filler, the
type and content of the conductive filler may be selected to obtain
electrical resistance values in accordance with the purpose of the
printed coating film, and for example, volume resistance values
range of no greater than 10.sup.-2 .OMEGA./cm, 10.sup.-2 .OMEGA./cm
to 10 .OMEGA./cm or 10 .OMEGA./cm to 10.sup.6 .OMEGA./cm may be
selected as appropriate. The conductive fillers may be used alone,
or several different types may be used in combination.
[0055] The conductive filler is preferably present in a dispersed
state with a mean particle size of no greater than 10 .mu.m in the
ink composition, in order to ensure a stabilized resistance value
for the printed matter. The content is preferably an amount
appropriate for the desired performance, in a content range of no
greater than 95 wt % in the ink composition, in order to obtain an
electrical resistance value suited for the purpose.
[0056] In a conductive ink composition for screen printing using a
conductive filler, it is preferred to use a polyester resin,
acrylic resin, epoxy resin, nitrocellulose resin, ethyl cellulose
resin, rosin-modified maleic acid resin, urethane acrylate
prepolymer, polyester acrylate prepolymer, epoxy acrylate
prepolymer or the like having a weight-average molecular weight of
about 3000 to 30000, or a resin or prepolymer comprising a
combination thereof, as a binder resin, at about 2 to 40 wt % with
respect to the total of the conductive ink composition for screen
printing. Furthermore, the solvent used may be the above-mentioned
solvent with a boiling point of 170.degree. C. or higher in an
amount of 70 wt % or greater of the total solvent, while as is
mentioned above, the conductive filler is preferably used in an
amount of no greater than 95 wt % with respect to the total
conductive ink composition for screen printing, depending on the
desired conductive performance, and if necessary, additives such as
antifoaming agents, leveling agents and dispersing agents may be
added.
[0057] Moreover, in a coating film formed using the conductive ink
composition for screen printing, when a volume resistance value of
lower than about 10.sup.-2 .OMEGA./cm is the target it is preferred
to use gold powder, silver powder, copper powder, iron powder,
indium powder or tungsten powder, and/or their oxides or complexes
in the conductive filler, when a volume resistance value of about
10.sup.-2 .OMEGA./cm to 10 .OMEGA./cm is the target it is preferred
to use graphite, carbon black or their combination in the
conductive filler, and when a volume resistance value of greater
than 10 .OMEGA./cm is the target it is preferred to mainly use
carbon black in the conductive filler.
[0058] The invention also provides printed matter produced by the
screen printing ink composition for screen printing onto an object
to be printed.
[0059] The invention still further provides a method for producing
printed matter, wherein printed matter is produced by the screen
printing ink composition for screen printing onto an object to be
printed.
[0060] In the printed matter and method for producing printed
matter provided by the invention, the object to be printed that is
used may be art paper, coated paper, various types of synthetic
paper, wood, painted slabs, glass, metal, polyester (PET),
polycarbonate (PC), acryl, polypropylene (PP), polyethylene (PE),
vinyl chloride or the like, which may be in the form of various
flat base materials, sheet-like base materials or film-like base
materials.
Examples
[0061] Examples and Comparative Examples of the invention are shown
in [Table 1] below. However, the invention is not limited to these
examples.
TABLE-US-00001 TABLE 1 Comp. Comp. Comp. Comp. Comp. Comp. Example
Example Example Example Example Example Example Example Example
Example Ex. Ex Ex. Ex. Ex. Ex. 1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6
<Ink composition components> Polyester resin (molecular
weight: 6000) 12.5 15.0 25.0 2.0 12.5 Polyester resin (molecular
weight: 28000) 10.0 15.0 5.0 20.0 12.5 5.0 Acrylic resin (molecular
weight: 100000) 5.0 25.0 20.0 8.0 25.0 5.0 10.0 Vinyl
chloride/vinyl acetate copolymer 5.0 25.0 10.0 10.0 resin
(molecular weight: 47000) Epoxy resin (molecular weight: 60000)
70.0 8.0 Urethane actylate (molecular weight: 2000) 75.0 80.0
Isophorone (boiling point: 216.degree. C.) 25.0 45.0 27.0 14.0 40.0
20.0 40.0 40.0 DBE (boiling point: 203-245.degree. C.) 20.0 10.0
2.0 30.0 12.0 10.0 25.0 10.0 3-Methoxy-3-methyl butanol 20.0 10.0
(boiling point: 174.degree. C.) Coal tar naphtha 2.8 2.0 5.0 5.0
20.0 (boiling point: 180-200.degree. C.) 1,6-Hexanediol diacrylate
7.0 3.0 (boiling point: .gtoreq.200.degree. C.) Dipentaerythritol
hexaacrylate 7.0 10.0 8.0 boiling point: .gtoreq.200.degree. C.)
1-Methoxypropyl-2-acetate 3.0 5.0 5.0 5.0 (boiling point:
146.degree. C.) 1-Methoxy-2-propanol 9.7 3.0 17.0 (boiling point:
120.degree. C.) Cyclohexanone (boiling point: 156.degree. C.) 7.0
4.0 15.0 7.0 9.0 Diacetone alcohol (boiling point: 168.degree. C.)
2.0 5.0 Carbon black pigment 10.0 5.0 15.0 5.0 10.0 10.0 5.0 5.0
Phthalocyanine green pigment 5.0 15.0 8.0 5.0 10.0 5.0 5.0 5.0
Conductive carbon black pigment 10.0 Graphite 20.0 Copper powder
85.0 Photoinitiator 4.0 4.0 Antifoaming agent, additives, etc. 5.0
5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 1.0 5.0 5.0 5.0 5.0 5.0 5.0 Silica
10.0 10.0 15.0 5.0 3.0 2.0 15.0 10.0 15.0 3.0 20.0 2.0 Talc 20.0
10.0 10.0 10.0 5.0 20.0 10.0 10.0 <Total component weight
ratio> 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0
100.0 100.0 100.0 100.0 100.0 100.0 101.0 <Object printed>
Polyester Polyester Polycarbonate Glass Acrylic Vinyl Coated
Acrylic Glass Glass Polyester Glass Acrylic Coated Polycarbonate
film film sheet board chloride sheet board film board sheet sheet
film <Physical property values> Viscosity [Pa s] 100.0 75.0
30.0 180.0 80.0 110.0 50.0 60.0 130.0 180.0 120.0 90.0 10.0 30.0
50.0 6.0 TI value [-] 7.0 6.0 8.0 2.0 4.0 5.0 3.0 5.0 2.5 5.0 6.0
8.0 3.0 1.0 10.0 2.0 Flow value [mm] 15.5 17.0 18.0 14.0 16.0 15.0
18.0 16.5 15.0 14.0 16.0 15.0 19.0 19.0 15.0 21.0 F60-F45 [mm] 0.4
0.6 0.2 1.0 0.7 0.8 1.0 0.6 0.3 0.2 0.5 0.1 1.0 1.2 0.1 1.5 Mean
particle size of particles in ink [.mu.m] 30.0 25.6 15.0 0.0 35.0
20.0 1.0 7.5 10.0 8.0 25.0 35.0 25.0 0.0 30.0 15.0 Image edge
spreading width [.mu.m] 5.0 6.0 4.0 10.0 6.0 9.0 10.0 7.0 8.0 4.0
6.0 2.0 20.0 25.0 0.0 30.0 <Printed image evaluation>
Evaluation of high-quality, high-definition G VG VG G G VG VG VG G
G F VG F P G P property of 100 .mu.m.phi. dot-printed image
Evaluation of high-quality, high-definition VG VG G G G VG G VG VG
VG F G F P G P property of 100 .mu.m lateral fine line-printed
image Evaluation of high-quality, high-definition VG VG G G VG G G
VG G G G P G VG F VG property of 100 .mu.m side-square solid
pattern In table 1, VG, G, F, and P mean following state.: VG: Very
Good Good: Good F: Fair P: Poor
[0062] For the ink compositions for screen printing of the examples
and comparative examples, the materials listed in Table 1 were
uniformly mixed by stirring using a propeller rotating stirrer, in
the mixing ratios (wt %) listed in the same table, and then
subjected to 2 passes of a triple roll mill disperser, and each
produced ink composition was measured for viscosity, TI value, flow
value (F60) and F60-F45 value by the methods described above.
[0063] Next, the ink compositions for screen printing of the
examples and comparative examples were screen printed onto the
objects to be printed listed in Table 1 with a screen printing
plate (emulsion thickness: 15 .mu.m, flat-processed on emulsion
surface), produced using an HS-D360 by Asada Mesh Co., Ltd. (mesh
filament diameter: 25 .mu.m.phi., calendered mesh thickness: 29
.mu.m, open area ratio: 42%, strength index: 2.56 as indicated by
Asada Mesh Co., Ltd.). The screen printing conditions were "a
squeegee with an 80 degree hardness, a clearance of 5 mm, pressing
with a squeegee printing pressure of 1.5 mm, a squeegee angle of 75
degrees, a squeegee speed of 100 mm/sec and pressing with a scraper
pressure of 1.5 mm."
[0064] The screen printing plate was one having a printed image
design comprising a 100 .mu.m.phi. dot pattern, a 100 .mu.m
longitudinal fine line pattern parallel to the printing direction,
a lateral fine line pattern that was perpendicular to the printing
direction and had a line width of 100 .mu.m at 150 .mu.m spacings,
and a square solid pattern with 100 mm sides.
[0065] The width of spreading at the image edges after the ink
compositions for screen printing of the examples and comparative
examples were printed was measured by observing the printed coating
film image sections printed with the lateral fine line pattern in
the screen printing plate, having line widths of 100 .mu.m at 150
.mu.m spacings and perpendicular to the printing direction, with a
length meter-mounted digital microscope at 200.times.
magnification, measuring the spacings between the printed lateral
fine lines, and calculating the difference from the printing plate
design spacing of 150 .mu.m. For example, when the spacings between
the printed lateral fine lines were 140 .mu.m, the difference from
the printing plate design spacing of 150 .mu.m was 10 .mu.m, but
since the image edges are on both sides of the lateral fine lines,
the width of spreading at the image edges on one side is 5 .mu.m,
and this was therefore recorded as the "image edge spreading
width."
[0066] Evaluation of the high-quality, high-definition property of
the printed images was made as follows based on direct visual and
200.times. magnified observation with a digital microscope. The
evaluation was conducted for 20th printed object.
Evaluation of [High-Quality, High-Definition Property of 100
.mu.m.phi. Dot-Printed Image] VG: Absolutely no defects such as
chipping in 100 dot shapes. G: Fine chipping, bleeding or shape
distortion of 1 to 5 dots out of 100. F: Chipping, bleeding or
shape distortion of 6 to 30 dots out of 100. P: Abnormalities in 31
or more dots out of 100.
Evaluation of [High-Quality, High-Definition Property of 100 .mu.m
Lateral Fine Line-Printed Image]
[0067] VG: Absolutely no defects such as spreading, distortion,
bleeding or chipping. G: Approximately 10 .mu.m enlargement or
thinning, but no loss due to bleeding or chipping. F: 11 .mu.m or
greater enlargement or thinning. P: Chipping of fine lines.
Evaluation of [High-Quality, High-Definition Property of 100 mm
Side-Square Solid Pattern]
[0068] VG: Printed image with satisfactory leveling property and
smoothness. G: Slightly inferior leveling property but within
allowable range for practical use. F: Leveling property within
allowable range for practical use, but printing abnormalities
occurred. P: Poor leveling property and unsuitable for practical
use, with printing abnormalities also present.
[0069] When the ink composition of Example 1 was used for black
matrix (lattice) printing with a line width of 200 .mu.m and screen
printing of black stripe lines with a 150 .mu.m line width,
high-definition screen printed matter was obtained with no defects
such as bleeding or chipping and a single-side spreading width of 5
.mu.m on the lines.
[0070] When the ink composition of Example 2 was used for resist
pattern printing including a 100 .mu.m line width, high-definition
screen printed matter was obtained with no defects such as bleeding
or chipping and a pattern edge spreading width of 6 .mu.m.
[0071] When the ink composition of Example 7 was used for spacer
pattern printing with an 80 .mu.m angle corner area and a 25 .mu.m
film thickness, high-definition screen printed matter was obtained
with no defects such as bleeding or chipping and a pattern edge
spreading width of 10 .mu.m.
[0072] When the ink composition of Example 8 was used for printing
of a light guiding panel dot group including a 100 .mu.m.phi. dot
pattern, high-definition screen printed matter was obtained with no
defects such as bleeding or chipping and a pattern edge spreading
width of 7 .mu.m.
[0073] As a result of measuring the volume resistance values of the
coating films formed with the ink compositions of Example 9 and
Example 10, they were 7.1.times.10.sup.-1 .OMEGA./cm and
3.4.times.10.sup.-1 .OMEGA./cm, respectively, confirming that the
expected performance as a conductive coating film was successfully
obtained.
* * * * *