U.S. patent application number 10/865912 was filed with the patent office on 2004-12-23 for actinic ray curable ink-jet ink and printed matter.
This patent application is currently assigned to KONICA MINOLTA MEDICAL & GRAPHIC, INC.. Invention is credited to Sasa, Nobusama.
Application Number | 20040259971 10/865912 |
Document ID | / |
Family ID | 33516126 |
Filed Date | 2004-12-23 |
United States Patent
Application |
20040259971 |
Kind Code |
A1 |
Sasa, Nobusama |
December 23, 2004 |
Actinic ray curable ink-jet ink and printed matter
Abstract
Disclosed is an actinic ray curable ink-jet ink comprising a
cationically polymerizable compound including a cationically
polymerizable epoxy compound and a cationically polymerizable
oxetane ring-containing compound, wherein the actinic ray curable
ink-jet contains the cationically polymerizable epoxy compound in
an amount of from 35 to 95% by weight based on the total amount of
cationically polymerizable compound, and wherein the cationically
polymerizable epoxy compound has a solubility parameter (sp value)
of from 10 to 20, and the cationically polymerizable oxetane
ring-containing compound has a solubility parameter (sp value) of
from 5 to 10.
Inventors: |
Sasa, Nobusama; (Sayama-shi,
JP) |
Correspondence
Address: |
Finnegan, Henderson, Farabow,
Garrett & Dunner, L.L.P.
1300 I Street, N.W.
Washington
DC
20005-3315
US
|
Assignee: |
KONICA MINOLTA MEDICAL &
GRAPHIC, INC.
|
Family ID: |
33516126 |
Appl. No.: |
10/865912 |
Filed: |
June 14, 2004 |
Current U.S.
Class: |
522/170 |
Current CPC
Class: |
B41M 7/0081 20130101;
C09D 11/101 20130101; G03F 7/027 20130101; Y10S 522/909 20130101;
Y10T 428/31511 20150401; G03F 7/038 20130101; Y10T 428/31504
20150401 |
Class at
Publication: |
522/170 |
International
Class: |
C08F 002/46 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 17, 2003 |
JP |
JP2003-171897 |
Claims
What is claimed is:
1. An actinic ray curable ink-jet ink comprising a cationically
polymerizable compound including a cationically polymerizable epoxy
compound and a cationically polymerizable oxetane ring-containing
compound, wherein the actinic ray curable ink-jet ink contains the
cationically polymerizable epoxy compound in an amount of from 35
to 95% by weight based on the total amount of cationically
polymerizable compound, and wherein the cationically polymerizable
epoxy compound has a solubility parameter (sp value) of from 10 to
20, and the cationically polymerizable oxetane ring-containing
compound has a solubility parameter (sp value) of from 5 to 10.
2. The actinic ray curable ink-jet ink of claim 1, wherein the
actinic ray curable ink-jet ink contains the cationically
polymerizable epoxy compound in an amount of from 50 to 95% by
weight based on the total amount of cationically polymerizable
compound.
3. The actinic ray curable ink-jet ink of claim 1, wherein the
actinic ray curable ink-jet ink contains the cationically
polymerizable epoxy compound in an amount of from 65 to 95% by
weight based on the total amount of cationically polymerizable
compound.
4. The actinic ray curable ink-jet ink of claim 1, wherein the
epoxy compound is epoxidized vegetable oil.
5. The actinic ray curable ink-jet ink of claim 1, further
comprising a vinyl ether compound.
6. The actinic ray curable ink-jet ink of claim 1, further
comprising a cationic photopolymerization initiator as an
initiator.
7. The actinic ray curable ink-jet ink of claim 1, further
comprising a radically polymerizable ethylenically unsaturated
compound.
8. The actinic ray curable ink-jet ink of claim 1, further
comprising pigment as a colorant.
9. The actinic ray curable ink-jet ink of claim 8, further
comprising a pigment dispersant.
10. The actinic ray curable ink-jet ink of claim 9, wherein the
pigment has an average particle size of from 10 to 150 nm.
11. The actinic ray curable ink-jet ink of claim 1, wherein the ink
has a viscosity at 25.degree. C. of 5 to 50 Pa.multidot.s.
12. A printed matter, prepared by supplying the actinic ray curable
ink-jet ink of claim 1 onto a recording medium.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to an actinic ray curable
ink-jet ink and a printed material using the same.
BACKGROUND OF THE INVENTION
[0002] Up to now, as an ink-jet ink exhibiting good water
resistance, there has been an ink which contains a water soluble
dye dispersed or dissolved in a high boiling point solvent, and
which contains a water soluble dye dissolved in a volatile solvent.
However, a dye is inferior to a pigment in resistance
characteristics such as light stability, and therefore ink using a
pigment as a coloring agent has been required. But, it is difficult
to disperse a pigment stably in an organic solvent, and it is also
difficult to ensure stable dispersibility and ejectibility. On the
other hand, in cases when ink using a high boiling solvent is
applied onto a non-absorptive recording medium, a solvent in the
ink is not volatized, results in difficulty of drying via
evaporation of the solvent. Accordingly, ink using high boiling
solvent cannot be printed on a non-absorptive recording medium.
[0003] Generally, ink using a volatile organic solvent can be
properly printed onto a non-absorptive recording medium, due to
adhesiveness of resin used and volatilization of the solvent.
However, such ink, in which the volatile solvent is a major
component, is easily dried at the nozzles of a recording head due
to volatilization of the solvent, requiring frequent maintenance.
Resistance of ink to some solvents may not be sufficient because
the ink essentially requires good solubility in a solvent used.
[0004] Further, in an on-demand printer using a piezo element,
usage of a large amount of a volatile solvent in ink increases
frequency of maintenance, and also tends to cause problems of
dissolution and swelling of members contacting the ink in the
printer. In addition, a volatile solvent has numerous restrictions
as a dangerous material under the Fire Defense Law. Consequently,
in an on-demand printer using a piezo element, it is necessary to
employ ink containing a volatile solvent in a small amount.
However, components used in an actinic ray curable ink usually are
ones having a relatively high viscosity. Therefore, it has been
difficult to design ink having a viscosity capable of being ejected
in conventional printers and further having good curability and
high stability.
[0005] In order to overcome the problems described above, an
actinic ray curable composition is disclosed (see for example,
Japanese Patent O.P.I. Publication No. 2001-220526) which contains
a cationic photopolymerization initiator, an epoxy compound, a
compound having an oxetane ring with a hydroxyl group, and a vinyl
ether. In the above document, the epoxy compound and the compound
having an oxetane ring with a hydroxyl group both are cationically
polymerizable compounds having a solubility parameter (sp value)
exceeding 10, and the epoxy compound content of the composition is
47 to 63% by weight based on the total weight of cationically
polymerizable compound. An extensive study of the above actinic ray
curable composition has been studied, and, as a result, it has been
proven that ink of this composition has problems in its curability,
strength of a cured layer therefrom, ejection stability from
nozzles, its adhesion to a substrate, solvent resistance, and water
resistance.
[0006] Further, an actinic ray curable composition is disclosed
(see for example, Japanese Patent O.P.I. Publication No.
2002-188035), which contains 10 to 50% by weight of a compound
having an oxirane ring, 50 to 90% by weight of a compound having an
oxetane ring and 0 to 40% by weight of a vinyl ether. In the patent
above document, the compound having an oxirane ring (epoxy
compound) is a cationically polymerizable compound having a
solubility parameter (sp value) exceeding 10, the epoxy compound
content of the composition is not more than 50% by weight based on
the total weight of cationically polymerizable compound, and some
of the compound having an oxetane ring have an sp value exceeding
10, and others have an sp value of not more than 10. An extensive
study of the above actinic ray curable composition has been
studied, and, as a result, it has been proven that ink of this
composition containing particularly a compound having an oxetane
ring and having an sp value exceeding 10 has problems in its
curability, strength of a cured layer therefrom, ejection stability
from nozzles, its adhesion to a substrate, solvent resistance, and
water resistance.
SUMMARY OF THE INVENTION
[0007] An object of the invention is to provide an actinic ray
curable ink-jet ink providing excellent photopolymerization
properties, good curability, high strength of a cured ink layer,
excellent ejection stability from nozzles, good adhesion to a
substrate, good solvent resistance, and good water resistance, and
to provide a printed matter prepared employing the actinic ray
curable ink-jet ink.
DETAILED DESCRIPTION OF THE INVENTION
[0008] The above object of the present invention is achieved by the
following:
[0009] 1. An actinic ray curable ink-jet ink comprising a
cationically polymerizable compound including a cationically
polymerizable epoxy compound and a cationically polymerizable
oxetane ring-containing compound, wherein the actinic ray curable
ink-jet ink contains the cationically polymerizable epoxy compound
in an amount of from 35 to 95% by weight based on the total amount
of cationically polymerizable compound, and wherein the
cationically polymerizable epoxy compound has a solubility
parameter (sp value) of from 10 to 20, and the cationically
polymerizable oxetane ring-containing compound has a solubility
parameter (sp value) of from 5 to 10.
[0010] 2. The actinic ray curable ink-jet ink of item 1 above,
wherein the actinic ray curable ink-jet ink contains the
cationically polymerizable epoxy compound in an amount of from 50
to 95% by weight based on the total amount of cationically
polymerizable compound.
[0011] 3. The actinic ray curable ink-jet ink of item 1 above,
wherein the actinic ray curable ink-jet ink contains the
cationically polymerizable epoxy compound in an amount of from 65
to 95% by weight based on the total amount of cationically
polymerizable compound.
[0012] 4. The actinic ray curable ink-jet ink of item 1 above,
wherein the epoxy compound is epoxidized vegetable oil.
[0013] 5. The actinic ray curable ink-jet ink of item 1 above,
further comprising a vinyl ether compound.
[0014] 6. The actinic ray curable ink-jet ink of item 1 above,
further comprising a cationic photopolymerization initiator as an
initiator.
[0015] 7. The actinic ray curable ink-jet ink of item 1 above,
further comprising a radically polymerizable ethylenically
unsaturated compound.
[0016] 8. The actinic ray curable ink-jet ink of item 1 above,
further comprising pigment as a colorant.
[0017] 9. The actinic ray curable ink-jet ink of item 8 above,
further comprising a pigment dispersant.
[0018] 10. The actinic ray curable ink-jet ink of item 9 above,
wherein the pigment has an average particle size of from 10 to 150
nm.
[0019] 11. The actinic ray curable ink-jet ink of item 1 above,
wherein the ink has a viscosity at 25.degree. C. of 5 to 50
Pa.s.
[0020] 12. A printed matter, prepared by supplying the actinic ray
curable ink-jet ink of item 1 above onto a recording medium.
[0021] 1-1. An actinic ray curable ink-jet ink comprising a
cationically polymerizable epoxy compound and a cationically
polymerizable oxetane ring-containing compound, wherein the actinic
ray curable ink-jet ink contains the cationically polymerizable
epoxy compound in an amount of from 35 to 95% by weight based on
the total amount of cationically polymerizable compound, and
wherein the cationically polymerizable epoxy compound has a
solubility parameter (sp value) of from 10 to 20, and the
cationically polymerizable oxetane ring-containing compound has a
solubility parameter (sp value) of from 5 to 10.
[0022] 1-2. The actinic ray curable ink-jet ink of item 1-1 above,
wherein the actinic ray curable ink-jet ink contains the
cationically polymerizable epoxy compound in an amount of from 50
to 95% by weight based on the total amount of cationically
polymerizable compound.
[0023] 1-3. The actinic ray curable ink-jet ink of item 1-1 above,
wherein the actinic ray curable ink-jet ink contains the
cationically polymerizable epoxy compound in an amount of from 65
to 95% by weight based on the total amount of cationically
polymerizable compound.
[0024] 1-4. The actinic ray curable ink-jet ink of any one of items
1-1 through 1-3 above, wherein the epoxy compound is epoxidized
vegetable oil.
[0025] 1-5. The actinic ray curable ink-jet ink of any one of items
1-1 through 1-4 above, further comprising a vinyl ether
compound.
[0026] 1-6. The actinic ray curable ink-jet ink of any one of items
1-1 through 1-5 above, further comprising a cationic
photopolymerization initiator as an initiator.
[0027] 1-7. The actinic ray curable ink-jet ink of any one of items
1-1 through 1-6 above, further comprising a radically polymerizable
ethylenically unsaturated compound.
[0028] 1-8. The actinic ray curable ink-jet ink of any one of items
1-1 through 1-7 above, further comprising pigment as a
colorant.
[0029] 1-9. The actinic ray curable ink-jet ink of item 1-8 above,
further comprising a pigment dispersant.
[0030] 1-10. The actinic ray curable ink-jet ink of item 1-8 or 1-9
above, wherein the pigment has an average particle size of from 10
to 150 nm.
[0031] 1-11. The actinic ray curable ink-jet ink of any one of
items 1-1 through 1-10 above, wherein the ink has a viscosity at
25.degree. C. of 5 to 50 Pa.s.
[0032] 1-12. A printed matter, prepared by supplying the actinic
ray curable ink-jet ink of any one of items 1-1 through 1-11 above
onto a recording medium.
[0033] Next, the present invention will be explained in detail.
[0034] As a pigment contained in the actinic ray curable ink-jet
ink of the invention (hereinafter also referred to as simply the
ink-jet ink of the invention) usable are inorganic achromatic
pigments such as carbon black, titanium oxide and potassium
carbonate or organic chromatic pigments. Examples of the organic
pigments include insoluble azo pigments such as Toluidine Red,
Toluidine Maroon, Hanza Yellow, Benzidine Yellow, and Pyrazolone
Red; soluble azo pigments such as Lithol Red, Helio Bordeaux,
Pigment Scarlet, and Permanent Red 2B; derivatives derived from vat
dyes such as Alizarine, indanthrone, and Thioindigo maroon;
phthalocyanine organic pigments such as Phthalocyanine Blue and
Phthalocyanine Green; quinacridone organic pigments such as
Quinacridone Red and Quinacridone Magenta; perylene organic
pigments such as Perylene Red and Perylene Scarlet; isoindolinone
organic pigments such as Isoindolinone Yellow and Isoindolinone
Orange; pyranthrone organic pigments such as Pyranthrone Red and
Pyranthrone Orange; thioindigo organic pigments; condensed azo
organic pigments; benzimidazolone organic pigments; quinophtharone
organic pigments such as Quinophthalone Yellow; isoindolin organic
pigments such as Isoindolin Yellow; and other pigments such as
flavanthrone yellow, acylamide yellow, nickel azo yellow, copper
azomethine yellow, perynone orange, anthrone orange,
dianthraquinonyl red, and dioxazine violet.
[0035] Examples of the organic pigments, represented by the Color
Index (C.I.) number, include C.I. Pigment Yellow 12, 13, 14, 17,
20, 24, 74, 83, 86, 93, 109, 110, 117, 125, 128, 129, 137, 138,
139, 147, 148, 150, 151, 153, 154, 155, 166, 168, 180, and 185;
C.I. Pigment Orange 16, 36, 43, 51, 55, 59, and 61; C.I. Pigment
Red 9, 48, 49, 52, 53, 57, 97, 122, 123, 149, 168, 177, 180, 192,
202, 206, 215, 216, 217, 220, 223, 224, 226, 227, 228, 238, and
240; C.I. Pigment Violet 19, 23, 29, 30, 37, 40, and 50; C.I.
Pigment Blue 15, 15:1, 15:3, 15:4, 15:6, 22, 60, and 64; C.I.
Pigment Green 7 and 36; and C.I. Pigment Brown 23, 25, and 26.
[0036] Of the foregoing pigments, quinacridone organic pigments,
phthalocyanine organic pigments, benzimidazolone organic pigments,
isoindolinone organic pigments, condensed azo organic pigments,
quinophthalone organic pigments, and isoindolin organic pigments
are preferred in view of light fastness. The organic pigments are
preferably pigment particles having an average particle diameter of
from 10 to 150 nm, which is determined utilizing a laser scattering
method. Pigments having an average particle diameter less than 10
nm lowers the light fastness due to the excessively small particle
diameter. On the other hand, pigments having an average diameter
exceeding 150 nm lowers dispersion stability in the dispersion
solution, whereby the pigments tend to precipitate.
[0037] Minute-sized organic pigments can be prepared, employing the
method described below. Namely, a clayey mixture, comprising at
least three components of an organic pigment, a water-soluble
inorganic salt in a factor of at least 3 by weight of the organic
pigment, and a water miscible solvent, is sufficiently kneaded to
result in minute particles, employing a kneader and the like.
Thereafter, the resulting mixture is poured in water and stirred
employing a high speed mixer to prepare a slurry. The resulting
slurry is repeatedly filtered and washed with water, whereby the
water soluble salt and the water miscible solvent are removed.
During preparation of the minute-sized organic pigments, resins and
pigment dispersing agents can be added. Listed as the water soluble
inorganic salt are sodium chloride and potassium chloride. The
inorganic salt is used in an amount 3 or more times the weight of
the organic pigment used, and preferably in an amount 20 or less
times the weight of the organic pigment used. When the weight of
the inorganic salt is less than 3 times the organic pigment, it is
impossible to prepare pigment particles of the desired particle
size. On the other hand, when the weight of the inorganic salt is
more than 20 times the organic pigment, excessively high load is
imposed on the washing process as a post-process, resulting in
substantial reduction of the processed amount of the organic
pigments.
[0038] Use of the water miscible solvent provides a mixture in a
clayey state, which contains pigment and a water soluble inorganic
salt used as a crushing aid, and eases efficient crushing. The
water miscible solvent is not specifically limited as long as it is
miscible in water. However, temperature of the mixture elevates
during kneading, and the solvent in the mixture tends to vaporize.
Therefore, from the viewpoint of safety, a high boiling point
solvent having a boiling point of from 120 to 250.degree. C. is
preferably used. Examples of the water miscible solvent include
2-methoxymethoxy)ethanol, 2-butoxyethanol, 2-(isopentyloxy)ethanol,
2-(hexyloxy)ethanol, diethylene glycol, diethylene glycol
monomethyl ether, diethylene glycol monoethyl ether, diethylene
glycol monobutyl ether, triethylene glycol, triethylene glycol
monomethyl ether, liquid polyethylene glycol, 1-methoxy-2-propanol,
1-ethoxy-2-propanol, dipropylene glycol, dipropylene glycol
monomethyl ether, dipropylene glycol monoethyl ether, and a low
molecular weight polypropylene glycol.
[0039] In the present invention, the pigment is incorporated in the
ink-jet ink in an amount of preferably from 3 to 15% by weight, in
order to obtain a high image density and sufficient light
fastness.
[0040] The cationically polymerizable epoxy compound (hereinafter
also referred to as simply the epoxy compound) in the invention is
a compound having one or more oxirane rings in the molecule, and
can be a monomer of a compound having an oxirane ring or an
oligomer of a compound having an oxirane ring. Examples thereof
include known aromatic epoxides, alicyclic epoxides, and aliphatic
epoxides. The oligomer has preferably a lower molecular weight, and
more preferably a molecular weight of less than 1000. In the
invention, the epoxy compound has a solubility parameter (sp value)
of from 10 to 20.
[0041] In the invention, the epoxy compound is preferably an
epoxidized vegetable oil. Examples thereof include an epoxidized
ester of fatty acid such as epoxy methyl stearate, epoxy butyl
stearate, epoxy octyl stearate, or epoxidized glyceride; epoxidized
soybean oil; epoxidized linseed oil; and epoxidized castor oil.
[0042] In the invention, the cationically polymerizable epoxy
compound is contained in the actinic ray curable ink-jet ink in an
amount of not less than 35% by weight, preferably more than 50% by
weight, and more preferably not less than 65% by weight, based on
the total weight of the cationically polymerizable compound in the
actinic ray curable ink-jet ink. When the cationically
polymerizable epoxy compound content is less than 35% by weight
based on the total weight of the cationically polymerizable
compound, it results in poor curability.
[0043] The oxetane ring-containing compound (hereinafter also
referred to as oxetane compound) in the invention is a compound
having one or more oxetane rings in the molecule, and a commonly
known oxetane compound is used. The oxetane compound in the
invention has an sp value of from 5 to 10. Preferred examples of
the oxetane compound in the invention include 1,4-bis
[(3-ethyl-3-oxetanyl)-methoxymethyl]benzene (OXT 121 etc.),
3-ethyl-3-(phenoxymethyl)oxetane (OXT 211 etc.), and
di(1-ethyl-3-oxetanyl) methyl ether (OXT 221 etc.), each produced
by Toa Gosei Co., Ltd. These can be used singly or as a mixture of
two or more thereof.
[0044] The sp value in the invention is determined according to the
following two methods described below. An epoxy compound whose sp
value, obtained by being measured according to at least one of the
two methods, falls within the range defined in the invention, is
the epoxy compound in the invention. An oxetane ring-containing
compound whose sp value, obtained by being measured according to at
least one of the two methods, falls within the range defined in the
invention, is the oxetane ring-containing compound in the
invention.
[0045] One method is a method calculating employing Okitsu formula
disclosed in Toshinao Okitsu, "Secchaku" Vol. 38, 6, 246-252
(1994), and the other method is a method calculating employing a
method according to Fedors, for example, URL
(http://pirica.comprises/chem/TCPEE/SP/CED.htm).
[0046] The content of the cationically polymerizable epoxy compound
in the actinic ray curable ink-jet ink of the invention is from 20
to 85 parts by weight, and preferably from 35 to 85 parts by
weight. The content of the cationically polymerizable oxetane
ring-containing compound in the actinic ray curable ink-jet ink of
the invention is from 14 to 54 parts by weight, and preferably from
14 to 47 parts by weight.
[0047] Examples of the vinyl ether compound contained in the
ink-jet ink of the invention include di- or tri-vinyl ether
compounds such as ethylene glycol divinyl ether, diethylene glycol
divinyl ether, triethylene glycol divinyl ether, propylene glycol
divinyl ether, dipropylene glycol divinyl ether, butane diol
divinyl ether, hexane diol divinyl ether, cyclohexane dimethanol
divinyl ether, and trimethylol propane trivinyl ether; and mono
vinyl ether compounds such as ethylene glycol monovinyl ether,
triethylene glycol monovinyl ether, hydroxyethyl monovinyl ether,
hydroxynonyl monovinyl ether, ethyl vinyl ether, n-butyl vinyl
ether, iso-butyl vinyl ether, octadecyl vinyl ether, cyclohexyl
vinyl ether, hydroxybutyl vinyl ether, 2-ethylhexyl vinyl ether,
cyclohexane dimethanol monovinyl ether, n-propyl vinyl ether,
isopropyl vinyl ether, isopropenyl ether-o-propylene carbonate,
dodecyl vinyl ether, diethylene glycol monovinyl ether, and
octadecyl vinyl ether.
[0048] In these vinyl ether compounds, when the hardenability,
adhesion or surface hardness is considered, di- or tri-vinyl ether
compounds are preferable, and particularly divinyl ether compounds
are preferable. In the present invention, these vinyl ether
compounds may be used alone or as an admixture of two or more kinds
thereof.
[0049] In the invention, the vinyl ether compound is a compound
which may be added to the ink-jet ink of the invention. However,
addition of the vinyl ether compound to the ink can lower viscosity
of the ink, and can increase the curing rate of the ink. The vinyl
ether compound is added in an amount of from 0 to 40% by weight,
and preferably from 0 to 20% by weight to a liquid composition
comprised of an oxirane ring-containing compound and an oxetane
ring-containing compound.
[0050] The total content of the cationically polymerizable compound
in the actinic ray curable ink-jet ink of the invention is from 55
to 99 parts by weight, and preferably from 70 to 95 parts by
weight.
[0051] Examples of the cationic photopolymerization initiator used
in the invention include arylsulfonium derivatives (for example,
Silacure UVI-6990 or Silacure UVI-6974 produced by Union Carbide
Co., Ltd., or Adekaoptomer SP-150, Adekaoptomer SP-152,
Adekaoptomer SP-170, or Adekaoptomer SP-172 produced by Asahi Denka
Kogyo Co., Ltd.); aryliodonium derivatives (for example, RP-2074
produced by Rodia Co., Ltd.); Arene-ion complexes (for example,
Irgacure 261 produced by Ciba Geigy Co., Ltd.); diazonium salts;
triazine type initiator; and other halogenides. The cationic
photopolymerization initiator content is preferably from 0.2 to 20
parts by weight of 100 parts by weight of cationically
polymerizable compound. The content less than 0.2 parts by weight
of the cationic photopolymerization initiator provides a poor
hardening property, and the content exceeding 20 parts by weight of
the cationic photopolymerization initiator does not exhibit a
further hardening property. These cationic photopolymerization
initiators may be used singly or as a mixture of two or more kinds
thereof.
[0052] Examples of a photopolymerization promoting agent include
anthracene; and anthracene derivatives (for example, Adekaoptomer
SP-100 produced by Asahi Denka Kogyo Co., Ltd.). These
photopolymerization promoting agents may be used singly or as a
mixture of two or more kinds thereof.
[0053] The radically polymerizable ethylenically unsaturated
compound is not specifically limited, as long as it is a known
compound. Examples thereof include (meth)acrylate compounds,
unsaturated polyesters, acryl-urethane compounds, and polythiols.
These may be used singly or in combination. Among these, a compound
having at least one (meth)acryl group in the molecule is preferred.
Examples thereof include a reaction product of an epoxy compound
and (meth)acrylic acid, (meth)acrylic esters derived from alcohols
and (meth)acrylic acid, urethane (meth)acrylate, polyester
(meth)acrylate, and polyether (meth)acrylate.
[0054] In the invention, a radical photopolymerization initiator
can be used. The radical photopolymerization initiator is not
specifically limited, as long as it is a known compound. Examples
thereof include benzil or its dialkylacetal derivatives,
acetophenone compounds, benzoin or its alkylether derivatives,
benzophenone compounds, and thioxanthones compounds.
[0055] Examples of the pigment dispersant include carboxylic acid
esters containing a hydroxyl group, salts of long chain
polyaminoamides with high molecular weight acid esters, high
molecular weight polycarboxylic acid salts, salts of long chain
polyaminoamides with polar acid esters, high molecular weight
unsaturated acid esters, high molecular copolymers, modified
polyurethanes, modified polyacrylates, polyether ester type anion
based surfactants, a salt of a naphthalenesulfonic acid formalin
condensation product, a salt of an aromatic sulfonic acid formalin
condensation product, polyoxyethylene alkylphosphoric acid esters,
polyoxyethylene nonyl phenyl ether, stearylamine acetate, and
pigment derivatives.
[0056] Typical examples of the pigment dispersants include
"Anti-Terra-U (a polyaminoamide phosphoric acid salt)",
"Anti-Terra-203/204 (a high molecular weight polycarboxylic acid
salt)", "Disperbyk-101 (polyaminoamide phosphoric acid salt and
acid ester), 107 (a hydroxyl group containing carboxylic acid
ester), 110 (an acid group containing copolymer), 130 (polyamide),
161, 162, 163, 164, 165, 166, and 170 (high molecular copolymer)",
"400", "Bykumen" (a high molecular weight unsaturated acid ester),
"BYK-P104, P105 (high molecular weight unsaturated polycarboxylic
acid)" "P104S, 240S (high molecular weight unsaturated acid
polycarboxylic acid and silicon based), and "Lactimon (long chain
amine, unsaturated acid polycarboxylic acid, and silicon)",
manufactured by BYK Chemie Co.
[0057] Further, listed are "Efka 44, 46, 47, 48, 49, 54, 63, 64,
65, 66, 71, 701, 764, and 766", "Efka Polymer 100 (modified
polyacrylate), 150 (an aliphatic modified polymer), 400, 401, 402,
403, 450, 451, 452, and 453 (modified polyacrylates), 745 (being
copper phthalocyanine based)", manufactured by Efka Chemicals Co.,
and "Flowlen TG-710 (urethane oligomer)", "Flownon SH-290,
SP-1000", "Polyflow No. 50E, and No. 300 (an acryl based
copolymer)", manufactured by Kyoei Kagaku Co., "Disparlon KS-860,
873SN, and 874 (a polymer dispersing agent), #2150 (aliphatic
multivalent carboxylic acid), and #7004 (polyether ester type)",
manufactured by Kusumoto Kasei Co.
[0058] Further, listed are "Demol RN and N (both are
naphthelenesulfonic acid formalin condensation product sodium
salts), MS, C, and SN-B (all are aromatic sulfonic acid formalin
condensation product sodium salts), and EP", "Homogenol L-18 (a
polycarboxylic acid type polymer)", "Emulgen 920, 930, 931, 935,
950, and 985 (all are polyoxyethylene nonyl phenyl ethers)", and
"Acetamin 24 (coconut amine acetate) and 86 (stearylamine
acetate)", manufactured by Kao Corp., "Solsperse 5000
(phthalocyanine ammonium salt based), 13240 and 13940 (both are
polyesteramine based), 17000 (being fatty acid amine based), 24000,
28000, and 32000", manufactured by Zeneca Corp., "Nikkol T106
(polyoxyethylene sorbitan monooleate), MYS-IEX (polyoxyethylene
monostearate), and Hexagline 4-0 (hexaglyceryl tetraoleate)",
manufactured by Nikko Chemical Co., Ltd.
[0059] The pigment dispersant content of ink is preferably from 0.1
to 10% percent by weight.
[0060] The ink-jet ink of the invention can be prepared by
dispersing pigment, an actinic ray curable compound and a pigment
dispersant in a conventional disperser such as a sand mill. It is
preferred that a solution containing a high concentration of
pigment prepared in advance is diluted with an actinic ray curable
compound. A conventional disperser can be used. Therefore, neither
excessive dispersion energy nor much dispersion time is necessary,
and ink with excellent stability is obtained without causing
deterioration of the ink components. It is preferred that the
dispersed ink composition is filtered with a filter with a pore
diameter of not more than 3 .mu.m, and then with a filter with a
pore diameter of not more than 1 .mu.m.
[0061] The ink-jet ink of the invention has a viscosity at
25.degree. C. of preferably from 5 to 50 Pa.multidot.s. Ink having
a viscosity at 25.degree. C. of from 5 to 50 Pa.multidot.s is
stably ejected not only from a recording head with a normal
frequency of 4 to 10 KHz but also from a recording head with a high
frequency of 10 to 50 KHz. Ink having a viscosity at 25.degree. C.
of less than 5 Pa.multidot.s lowers a following property of ink
ejection from a recording head with a high frequency, and ink
having a viscosity at 25.degree. C. exceeding 50 Pa.multidot.s
lowers ink ejection stability, resulting in incapability of
ejection, even if a recording head is provided with a viscosity
decreasing mechanism for lowering ink viscosity such as a
heater.
[0062] It is preferred that the ink-jet ink of the invention used
in a piezo type recording head be adjusted to an
electroconductivity of not more than 10 .mu.S/cm so that the inside
of the head is not corroded by ink the composition. It is preferred
that the electroconductivity of the ink composition used in a
continuous type recording head be adjusted by an electrolyte to not
less than 0.5 mS/cm.
[0063] As resins for a recording medium used in the invention,
conventional synthetic resins widely used for various use can be
used. Examples of the resins include polyester, polyethylene,
polyurethane, polypropylene, acryl resin, polycarbonate,
polystyrene, acrylonitrile-butadiene-styrene copolymer,
polyethylene terephthalate, and polybutadiene terephthalate.
Thickness or form of the recording medium comprised of these resins
is not specifically limited.
[0064] Usage of the ink-jet ink of the invention is as follows: The
ink-jet ink is incorporated in a recording head of an ink jet
printer, ejected from the recording head onto a recording medium,
and exposing the ejected ink on the recording medium to actinic
rays such as ultraviolet light and an electron beam, whereby the
ink on the recording medium is rapidly cured.
[0065] Examples of a light source for actinic ray include a mercury
arc lamp, a xenon arc lamp, a fluorescent lamp, a carbon arc lamp,
a tungsten-halogen lamp, and sunlight. When electron beam is used
for actinic ray, the ink is ordinarily cured employing an electron
beam having energy of not more than 300 eV, but can be instantly
cured instantly by irradiation of 1 to 5 Mrad.
EXAMPLES
[0066] The invention will now be explained employing examples,
however, the embodiments of the invention are not limited
thereto.
[0067] <<Preparation of Inventive Ink Samples 1 Through
8>>
[0068] A mixture of pigment, a pigment dispersant, an epoxy
compound, an oxetane compound, and optionally a vinyl ether
compound as shown in Table 1 was dispersed in a sand mill for 4
hours to obtain an actinic ray curable ink liquid. Thereafter, the
resulting ink liquid was mildly mixed with the initiator as shown
in Table 1, and filtered under pressure employing a membrane filter
to obtain an actinic ray curable ink-jet ink. Thus, inventive ink
samples 1 through 8 were obtained.
[0069] [Preparation of Printed Matter]
[0070] Each of the inventive ink samples obtained above was ejected
onto a polyethylene terephthalate recording sheet employing an ink
jet printer with a piezo type recording head, and then the ink on
the recording sheet was cured employing a UV light source (with 8
cold-cathode tubes: 20 W output power), while the recording sheet
was transported at a rate of from 200 to 1000 mm/second. Thus,
printed matter was obtained.
1 TABLE 1 Inventive ink sample No. 1 2 3 4 5 6 7 8 Pigment P1 5 5 5
5 5 5 5 5 (weight parts) Epoxy E1 50 50 compound (weight parts) E2
65 65 (weight parts) E3 60 60 (weight parts) E4 65 65 (weight
parts) Oxetane OXT221 37 27 30 27 compound (weight parts) OXT121 22
17 17 17 (weight parts) OXT211 10 (weight parts) OXT212 5 (weight
parts) Vinyl ether DVE-3 7 5 10 5 compound (weight parts) Pigment
32000 3 3 3 3 3 3 3 3 dispersant (weight parts) Initiator SP-152 5
5 5 5 5 5 5 5 (weight parts)
[0071] Details of the components described in Table 1 are as
follows:
[0072] Pigment
[0073] P1: Crude copper phthalocyanine ("Copper phthalocyanine"
produced by Toyo Ink Manufacturing Co., Ltd.) of 250 parts, 2500
parts of sodium chloride, and 160 parts of polyethylene glycol
(Polyethylene glycol 300 produced by Tokyo Kasei Co., Ltd.) were
placed in a 4.55 liter (1 gallon) polystyrene kneader (produced by
Inoue Seisakusho o., Ltd.) and kneaded for 3 hours. The resulting
mixture was poured into a 2.5 liter hot water, and stirred in a
high speed mixer at about 80.degree. C. for about one hour to
obtain a slurry. The resulting slurry was filtered off, washed with
water 5 times to eliminate the sodium chloride and the solvent, and
dried employing a spray drying method. Thus, Pigment P1 was
obtained.
[0074] Epoxy Compounds
[0075] E1: Celoxide 2021P: (Alicyclic epoxide produced by Daiseru
Kagaku Co., Ltd.)
[0076] E2: Celoxide 3000: (Alicyclic epoxide produced by Daiseru
Kagaku Co., Ltd.)
[0077] E3: Vikoflex 9010 (Epoxidized vegetable oil ester produced
by ATOFINA Co., Ltd.)
[0078] E4: Vikoflex 9040 (Epoxidized vegetable oil ester produced
by ATOFINA Co., Ltd.)
[0079] Oxetane Compounds
[0080] OXT221: Oxetane compound (produced by Toa Gosei Co.,
Ltd.)
[0081] OXT121: Oxetane compound (produced by Toa Gosei Co.,
Ltd.)
[0082] OXT211: Oxetane compound (produced by Toa Gosei Co.,
Ltd.)
[0083] OXT212: Oxetane compound (produced by Toa Gosei Co.,
Ltd.)
[0084] OXT101: Oxetane compound (produced by Toa Gosei Co.,
Ltd.)
[0085] Vinyl Ether Compound
[0086] DVE-3: Triethylene glycol divinyl ether (produced by ISP
Co., Ltd.)
[0087] Pigment Dispersant
[0088] 32000: Aliphatic group modified compound ("Solsperse 32000"
(produced by Zeneca Co., Ltd.)
[0089] Initiator
[0090] SP-152: Triphenyl sulfonium salt ("Adekaoptomer SP-152"
produced by Asahi Denka)
[0091] The solubility parameter (sp value) of the compounds used is
shown in Table 2.
2TABLE 2 (sp value) Okitsu method Fedors method E1 13.60 12.02 E2
7.10 10.52 E3 10.81 -- E4 10.35 -- OXT221 6.57 8.49 OXT121 7.70
8.31 OXT211 7.80 9.71 OXT212 7.28 8.49 OXT101 10.73 12.36
[0092] [Preparation of Comparative Ink Samples 1 and 2]
[0093] Comparative ink samples 1 and 2 were prepared in the same
manner as above, except that the components as shown in Table 3
below were used.
3 TABLE 3 Comparative ink sample No. 1 2 Pigment P1 (weight parts)
5 5 Epoxy compound E1 (weight parts) 50 E2 (weight parts) 30
Oxetane compound OXT121 (weight parts) 57 OXT101 (weight parts) 27
Vinyl ether compound DVE-3 (weight parts) 10 Pigment dispersant
32000 (weight parts) 3 3 Initiator SP-152 (weight parts) 3 3
[0094] [Preparation of Printed Matter]
[0095] Printed matter was obtained in the same manner as above,
except that comparative ink sample 1 or 2 was used.
[0096] With respect to inventive ink samples 1 through 8 and
comparative ink samples 1 and 2 obtained above, and printed matter
obtained employing them, the following evaluations were carried
out. The results are shown in Table 4.
[0097] The evaluations were carried out as follows.
[0098] Curability
[0099] Curability was represented by the transporting rate
(mm/second) in the used UV light source of the recording sheet at
which tackiness of the printed ink is not perceived by fingering.
The higher transporting rate reduces irradiation energy necessary
to cure, and provides better curability.
[0100] Ejection Stability
[0101] After 30 minutes' continuous ink ejection was carried out,
clogging of nozzles from which ink was ejected was observed and
evaluated according to the following criteria:
[0102] A: After 30 minutes' continuous ink ejection, no clogging of
nozzles was observed
[0103] B: After 30 minutes' continuous ink ejection, no clogging of
nozzles was observed, but satellite occurred.
[0104] C: After 30 minutes' continuous ink ejection, clogging of
nozzles was observed.
[0105] Strength of Ink Layer
[0106] Scratch test was carried out, in which the ink layer formed
was scratched with a fingernail, and the strength of ink layer was
evaluated according to the following criteria:
[0107] A: No ink layer was peeled off by scratch.
[0108] B: A part of the ink layer was peeled off by strong
scratch.
[0109] C: The ink layer was easily peeled off by scratch.
[0110] Adhesion Property
[0111] A cross-cut adhesion test was carried out according to a
method as described in JIS K5400. Eleven cut lines at an interval
of 1 mm were formed in the transverse and longitudinal directions
on images of the printed matter obtained above to form one hundred
grids. Then, a cellophane tape (R) was adhered to the formed grids
and sharply peeled off perpendicularly (cross-cut adhesion
test).
[0112] Similarly, a cellophane tape (R) was adhered to images of
the printed matter without cut lines, and sharply peeled off
perpendicularly (simple adhesion test).
[0113] Evaluation was carried out according to the following
criteria:
[0114] A: No peeled images were observed at the cross-cut adhesion
test.
[0115] B: Some peeled images were observed at the cross-cut
adhesion test, but no peeled images without cut lines were observed
at the simple adhesion test.
[0116] C: Peeled images were observed at both adhesion tests
above.
[0117] Solvent Resistance and Water Resistance
[0118] Printed matter obtained employing each of the ink samples
was immersed in 50.degree. C. alcohol or in 50.degree. C. water for
10 seconds, breakage and shrinkage of the printed image were
observed and evaluated according to the following criteria:
[0119] A: No change was observed.
[0120] B: A slight breakage and shrinkage was observed.
[0121] C: Apparent breakage and shrinkage was observed.
4TABLE 4 Cura- Ink bility Strength Solvent Water sample (mm/
Ejection of ink Adhesion resis- resis- No. seconds) stability layer
property tance tance 1 (Inv.) 500 A A A A A 2 (Inv.) 400 A A A A A
3 (Inv.) 400 A A A A A 4 (Inv.) 500 A A A A A 5 (Inv.) 500 A A A A
A 6 (Inv.) 500 A A A A A 7 (Inv.) 500 A A A A A 8 (Inv.) 500 A A A
A A 1 (Comp.) 800 C C B C B 2 (Comp.) 1000 C C C C C Inv.:
Invention, Comp.: Comparative
[0122] As is apparent from Table 4, the inventive ink samples
provide good curability, high strength of a cured ink layer,
excellent stability of ejection from nozzles, good adhesion to a
recording sheet, good solvent resistance and good water resistance,
as compared with the comparative ink samples.
EFFECTS OF THE INVENTION
[0123] The present invention can provide an actinic ray curable
ink-jet ink providing excellent photopolymerization properties,
good curability, high strength of a cured ink layer, excellent
stability of ejection from nozzles, good adhesion to a substrate,
good solvent resistance, and good water resistance, and provide a
printed matter prepared employing the actinic ray curable ink-jet
ink.
* * * * *
References