U.S. patent application number 13/478481 was filed with the patent office on 2012-09-13 for photocurable ink composition, ink jet recording method, and recording matter.
This patent application is currently assigned to SEIKO EPSON CORPORATION. Invention is credited to Hiroshi Fukumoto, Keitaro Nakano, Takashi Oyanagi.
Application Number | 20120229583 13/478481 |
Document ID | / |
Family ID | 40553584 |
Filed Date | 2012-09-13 |
United States Patent
Application |
20120229583 |
Kind Code |
A1 |
Fukumoto; Hiroshi ; et
al. |
September 13, 2012 |
PHOTOCURABLE INK COMPOSITION, INK JET RECORDING METHOD, AND
RECORDING MATTER
Abstract
An ink jet recording method having the steps of discharging a
photocurable ink composition comprising a monomer expressed by
CH.sub.2.dbd.CR.sup.1--COO--R.sup.2--O--CH.dbd.CH--R.sup.3 (R.sup.1
denotes a hydrogen atom or a methyl group, R.sup.2 denotes an
organic residue having a carbon number of 2 to 20, and R.sup.3
denotes a hydrogen atom or an organic residue having a carbon
number of 1 to 11), irradiating said photocurable ink composition
at an irradiating intensity is 70 mW/cm.sup.2 or more using an
ultraviolet ray irradiating apparatus is provided herewith.
Inventors: |
Fukumoto; Hiroshi;
(Shiojori-shi, JP) ; Nakano; Keitaro;
(Motsumoto-shi, JP) ; Oyanagi; Takashi;
(Matsumoto-shi, JP) |
Assignee: |
SEIKO EPSON CORPORATION
Tokyo
JP
|
Family ID: |
40553584 |
Appl. No.: |
13/478481 |
Filed: |
May 23, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12188429 |
Aug 8, 2008 |
8192804 |
|
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13478481 |
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Current U.S.
Class: |
347/102 |
Current CPC
Class: |
Y10T 428/24802 20150115;
B41M 5/0023 20130101; C09D 11/30 20130101; C09D 11/101
20130101 |
Class at
Publication: |
347/102 |
International
Class: |
B41J 2/01 20060101
B41J002/01 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 8, 2007 |
JP |
2007-207234 |
Aug 4, 2008 |
JP |
2008-200962 |
Claims
1.-8. (canceled)
9. An ink jet recording method comprising: discharging a
photocurable ink composition comprising a monomer having the
formula CH.sub.2.dbd.CR.sup.1--COO--R.sup.2--O--CH.dbd.CH--R.sup.3
wherein R.sup.1 denotes a hydrogen atom or a methyl group, R.sup.2
denotes an organic residue having 2 to 20 carbon atoms, and R.sup.3
denotes a hydrogen atom or an organic residue having 1 to 11 carbon
atoms; and a photo-polymerization initiator; and irradiating said
photocurable ink composition at an irradiating intensity is 70
mW/cm.sup.2 or more using an ultraviolet ray irradiating
apparatus.
10. The recording method of claim 9, wherein irradiating comprising
irradiating at wavelength in a range of 350 to 450 nm.
11. The recording method of claim 9, wherein the ultraviolet ray
irradiating apparatus is a ultraviolet ray light emitting
diode.
12. The recording method of claim 9, wherein the monomer is
2-(vinyloxyethoxy)ethyl acrylate, 2-(vinyloxyethoxy)ethyl
methacrylate, or a combination thereof.
13. The recording method of claim 9, wherein the photocurable ink
composition comprise 20 to 90% by weight monomer.
14. The recording method of claim 9, wherein the photocurable ink
composition has a viscosity of less than 25 mPas at 20.degree.
C.
15. The recording method of claim 9, wherein the
photo-polymerization initiator is an .alpha.-aminoketone, an
.alpha.-hydroxyketone, an acylphosphine oxide, or a combination
thereof.
16. The recording method of claim 9, wherein the photocurable ink
composition comprises 1 to 20% by weight photo-polymerization
initiator.
Description
[0001] Priority is claimed to Japanese Patent Applications No.
2007-207234, filed Aug. 8, 2007, and No. 2008-200962, filed Aug. 4,
2008, the disclosures of which, including the specifications,
drawings and claims, are incorporated herein by reference in their
entireties.
BACKGROUND
[0002] 1. Technical Field
[0003] The present invention relates to a photocurable ink
composition, an ink jet recording method using the same, and a
recorded material.
[0004] 2. Related Art
[0005] A photocurable ink composition is used for manufacture of a
color filter, printing on a printed board, printing on a plastic
card, a vinyl sheet or a plastic component, printing of a
large-sized signboard or an indoor/outdoor advertisement, or
printing of a barcode or a date.
[0006] Japanese Unexamined Patent Application No. 2004-99796
discloses a photocurable ink composition including dendrimer which
is a kind of dendritic polymer. The dendritic polymer has a
molecule structure in which a functional group is dense in the
surface with high density compared with a general linear polymer
and thus is expected as a functional polymer nano material.
[0007] However, if the dendritic polymer is added to the ink
composition, the viscosity of an ink is significantly increased and
thus, even in view of storage stability, a discharge failure of an
ink jet head may occur due to the increase of the viscosity. In
order to suppress the increase of the viscosity, the reduction of
the addition amount of the dendritic polymer has a tradeoff
relation with the characteristic improvement due to the adding of
the dendritic polymer.
[0008] As a general method of preventing the high viscosity of the
ink, there is a method of using a low-viscosity polymerizable
compound as a diluted monomer. However, the low-viscosity monomer
generally has a low molecular weight, a low flash point, and
problems in stability, such as odor and skin irritability. As
another method, water or an organic solvent without polymerizable
functional group as a low-viscosity dilution agent is added.
However, when a component which does not contribute to a curing
reaction is added, a drying process should be performed by a
heating or ventilating unit as a pre-process of the curing
reaction, or a special process of providing an absorbing layer on a
recording medium needs to be performed. Accordingly, a process load
is undesirably increased. When the curing reaction is performed in
a state in which the drying process is insufficient, a residual
solvent or residual moisture is foamed by heat of polymerization or
is extruded from a cured material, is bled out and is left on the
surface of the cured film, thereby causing tackiness
(stickiness).
SUMMARY
[0009] An advantage of some aspects of the invention is that it
provides a photo-curable ink composition with excellent storage
stability, stability and curing properties and excellent film
quality after curing, an ink cartridge using the same, an ink jet
recording method, and a recorded material.
[0010] According to an aspect of the invention, there is provided a
photocurable ink composition comprising a dendritic polymer; a
monomer expressed by
CH.sub.2.dbd.CR.sup.1--COO--R.sup.2--O--CH.dbd.CH--R.sup.3 (R.sup.1
denotes a hydrogen atom or a methyl group, R.sup.2 denotes an
organic residue having a carbon number of 2 to 20, and R.sup.3
denotes a hydrogen atom or an organic residue having a carbon
number of 1 to 11); and a photopolymerization initiator.
[0011] The dendritic polymer may be a dendrimer and/or a
hyperbranched polymer.
[0012] The monomer may be 2-(vinyloxyethoxy)ethyl acrylate and/or
2-(vinyloxyethoxy)ethyl methacrylate.
[0013] The concentration of the dendritic polymer may be in a range
from 3% by weight to 30% by weight.
[0014] The photo-curable ink composition may further include a
coloring material.
[0015] The photopolymerization initiator may be obtained by mixing
any one kind or two or more kinds of .alpha.-aminoketone,
.alpha.-hydroxyketone, and acylphosphine oxide.
[0016] According to another aspect of the invention, there is
provided an ink jet recording method comprising performing
recording using the photocurable ink composition.
[0017] According to another aspect of the invention, there is
provided a recorded material recorded using the photo-curable ink
composition.
[0018] According to an aspect of the invention, it is possible to
provide a photo-curing ink composition which is excellent in
storage stability, stability, curing properties and film quality
after curing. According to another aspect of the invention, it is
possible to provide an ink jet recording method which is excellent
in storage stability, stability, a curing rate and film quality,
and a recorded material having excellent film quality.
DESCRIPTION OF EXEMPLARY EMBODIMENT
[0019] Hereinafter, the exemplary embodiments of the present
invention will be described.
[0020] Photo-Curable Ink Composition
[0021] An photo-curable ink composition according to the present
embodiment includes a dendritic polymer and a monomer expressed by
Formula CH.sub.2.dbd.CR.sup.1--COO--R.sup.2--O--CH.dbd.CH--R.sup.3
(R.sup.1 denotes a hydrogen atom or a methyl group, R.sup.2 denotes
an organic residue having a carbon number of 2 to 20, and R.sup.3
denotes a hydrogen atom or an organic residue having a carbon
number of 1 to 11). The photo-curable ink composition according to
the present embodiment includes a photo-polymerization initiator
and a coloring material (coloring agent) in addition to the above
component.
[0022] According to the present embodiment, by adding the dendritic
polymer to the ink composition, it is possible to improve curing
properties of the ink composition and film quality after curing. In
order to suppress the increase of the viscosity due to the addition
of the dendritic polymer, a monomer is added to the ink
composition. The monomer of the present invention contributes to a
polymerization reaction and thus does not need to be subjected to
an additional process such as a drying process. Since a general
low-viscosity monomer has a low flash point, a stability problem
may occur in the addition to the ink composition. However, in the
present embodiment, by employing the monomer expressed by the above
formula, it is possible to suppress the decrease of the flash
point, and improve the stability of the ink composition. In
addition, the monomer has excellent curing properties.
[0023] The dendritic polymer can be roughly classified into six
structures as described below (see Keigo AOI and Masaaki KAKIMOTO
Ed., Dendritic Polymers--Highly functionalized world by which the
multi-branched structure is widened--(in Japanese), published by
NTS Inc.).
[0024] I Dendrimer
[0025] II Linear dendritic polymer
[0026] III Dendri-graft polymer
[0027] IV Hyperbranched polymer
[0028] V Star-hyperbranched polymer
[0029] VI hyper-graft polymer
[0030] Of these, I to III have a degree of branching (DB) of 1 and
have a defect-free structure, whereas IV to VI have a random
branched structure which may contain a defect. In particular, as
compared with generally used linear high-molecular weight
compounds, a dendrimer has a possibility to dispose a reactive
functional group in a high density and with concentration on the
outermost plane thereof and is highly expected as a functional
high-molecular weight material. Also, a hyperbranched polymer,
although not comparable to the dendrimer, has a possibility to
introduce a number of reactive functional groups on the outermost
layer thereof and has excellent curing properties.
[0031] Different from conventional linear high-molecular weight
compounds or branched high-molecular weight compounds, these
dendritic polymers repeat a three-dimensional branched structure
and are highly branched. For that reason, as compared with linear
high-molecular weight compounds having the same molecule, the
dendritic polymers have a possibility to control the viscosity on a
low level.
[0032] Examples of a synthetic method of a dendrimer which can be
used in the present embodiment include a divergent method in which
the synthesis is performed from the center toward the outside and a
convergent method in which the synthesis is performed from the
outside toward the center.
[0033] As the dendrimer and hyperbranched polymer which can be used
in the present embodiment, ones which are solids at room
temperature and which have number average molecular weights ranging
from 1,000 to 100,000 are desirable; and in particular, ones having
number average molecular weights ranging from 2,000 to 50,000 are
preferably used. In the case where the polymer is not a solid at
room temperature, the maintenance properties of a formed image
become worse. Also, in the case where the molecular weight is lower
than the foregoing range, a fixed image becomes brittle; whereas in
the case where the molecular weight exceeds the foregoing range,
even when the addition amount is decreased, the viscosity of an ink
is excessively high so that the ink is not practically useful in
view of a flying characteristic.
[0034] Also, the dendrimer and hyperbranched polymer which can be
used in the present embodiment are preferably a dendrimer and a
hyperbranched polymer, respectively, each of which has a radical
polymerizable functional group on the outermost plane thereof. By
employing a structure in which radical polymerization can be
achieved on the outermost plane thereof, a polymerization reaction
rapidly proceeds.
[0035] Examples of the polymer having a dendrimer structure include
amidoamine based dendrimers (as described in U.S. Pat. Nos.
4,507,466, 4,558,120, 4,568,737, 4,587,329, 4,631,337 and
4,694,064) and phenyl ether based dendrimers (as described in U.S.
Pat. No. 5,041,516 and Journal of American Chemistry, Vol. 112,
pages 7638 to 7647 (1990)). As to the amidoamine based dendrimer, a
dendrimer having a terminal amino group and a methyl carboxylate
group is commercially available as "STARBURST.TM. (PAMAM)" from
Aldrich. Also, the terminal amino group of such an amidoamine based
dendrimer can be allowed to react with an acrylic acid derivative
or a methacrylic acid derivative of various kinds to synthesize an
amidoamine based dendrimer having a corresponding terminal, which
is then provided for use.
[0036] Examples of the acrylic acid derivative or methacrylic acid
derivative which can be used include, but are not limited to,
acrylic acid or methacrylic acid alkyl esters of methyl, ethyl,
n-butyl, t-butyl, cyclohexyl, palmityl, stearyl, etc.; and acrylic
acid or methacrylic acid alkylamides of acrylamide, isopropylamide,
etc.
[0037] Also, as to the phenyl ether based dendrimer, various
compounds are described in, for example, Journal of American
Chemistry, Vol. 112, pages 7638 to 7647 (1990). For example, it is
described that 3,5-dihydroxybenzyl alcohol is used and allowed to
react with 3,5-diphenoxybenzyl bromide to synthesize a
second-generation benzyl alcohol; an OH group thereof is converted
to Br by using CBr.sub.4 and triphenylphosphine; thereafter, the
resulting benzyl alcohol is similarly allowed to react with
3,5-dihydroxybenzyl alcohol to synthesize a next-generation benzyl
alcohol; and subsequently, the foregoing reactions are repeated to
synthesize a desired dendrimer. As to the phenyl ether based
dendrimer, the terminal can be substituted with one having a
chemical structure of various kinds in place of the terminal benzyl
ether linkage. For example, in synthesizing the dendrimer as
described in Journal of American Chemistry, Vol. 112, by using an
alkyl halide of various kinds in place of the foregoing benzyl
bromide, a phenyl ether based dendrimer having a terminal structure
having a corresponding alkyl group is obtainable. Besides,
polyamine based dendrimers (as described in Macromol. Symp., 77, 21
(1994)) and derivatives thereof having a modified terminal group
can be used.
[0038] As the hyperbranched polymer, for example, hyperbranched
polyethylene glycol can be used. The hyperbranched polymer is one
obtained by synthesizing a target polymer in one stage by using a
monomer having two or more reaction points of one kind
corresponding to a branched portion and only one reaction point of
another kind corresponding to a connecting portion in one molecule
thereof (see Macromolecules, Vol. 29, pages 3831 to 3838 (1996)).
Examples of a monomer for the hyperbranched polymer include
3,5-dihydroxybenzoic acid derivatives. When an example of the
production of the hyperbranched polymer is concerned,
poly[bis(triethylene glycol)benzoate], which is a hyperbranched
polymer, can be synthesized by heating methyl
3,5-bis((8'-hydroxy-3',6'-dioxaoctyl)oxy)benzoate which is a
hydrolyzate of methyl
3,5-bis((8'-(t-butyldiphenyloxy)-3',6'-dioxaoctyl)oxy)benzoate
obtainable from 1-bromo-8-(t-butyldiphenyloxy)-3,6-dioxaoctane and
methyl 3,5-dihydroxybenzoate together with dibutyltin diacetate
under a nitrogen atmosphere.
[0039] In the case where 3,5-dihydroxybenzoic acid is used, since
the hyperbranched polymer terminal group is a hydroxyl group, a
hyperbranched polymer having a terminal group of various kinds can
be synthesized by using an appropriate alkyl halide with respect to
this hydroxyl group.
[0040] In a monodispersed polymer or hyperbranched polymer having a
dendrimer structure or the like, its characteristic is dominated by
a chemical structure of the principal chain and a chemical
structure of the terminal group. In particular, its characteristic
is largely different depending upon a difference of the terminal
group or the substituent in the chemical structure. In particular,
a polymer having a polymerizable group in a terminal thereof has a
large gelation effect after photoreaction and is useful because of
its reactivity. The dendrimer having a polymerizable group is
obtained through chemical modification with a polymerizable
group-containing compound in a terminal of a polymer having a basic
atomic group such as an amino group, a substituted amino group and
a hydroxyl group in a terminal thereof.
[0041] For example, the dendrimer having a polymerizable group is
synthesized by adding, for example, an isocyanate group-containing
vinyl compound to a polyfunctional compound obtained by subjecting
an amino based dendrimer to Michael addition with an active
hydrogen-containing (meth)acrylate based compound. Also, a
dendrimer having a polymerizable group in a terminal thereof is
obtained by allowing an amino based dendrimer to react with
(meth)acrylic acid chloride, etc. Examples of such a vinyl compound
capable of giving a polymerizable group include compounds having a
radical polymerizable, ethylenically unsaturated bond. Examples of
such a compound having a radical polymerizable, ethylenically
unsaturated bond include unsaturated carboxylic acids, for example,
acrylic acid, methacrylic acid, itaconic acid, crotonic acid,
isocrotonic acid and maleic acid, and salts thereof; and various
compounds having a radical polymerizable, ethylenically unsaturated
bond as described below.
[0042] Furthermore, examples of the polymerizable group include
cationic polymerizable group-containing terminal groups. Such a
terminal group can be introduced by allowing a compound having a
polymerizable group which is polymerized upon cationic
polymerization (for example, an epoxy group and an oxetanyl group),
such as cyclic ether compounds (for example, oxirane and oxetane),
alicyclic polyepoxides, polyglycidyl esters of a polybasic acid and
polyglycidyl ethers of a polyhydric alcohol, to react with the
foregoing amino based dendrimer. For example, by allowing
chloromethyl oxirane to react with the amino based dendrimer, a
cationic polymerizable group of an epoxy type can be introduced in
a terminal thereof. Besides, examples of the terminal group include
cationic polymerizable groups selected among styrene derivatives,
vinylnaphthalene derivatives, vinyl ethers and N-vinyl
compounds.
[0043] In the present embodiment, the dendrimer and the
hyperbranched polymer of one kind may be solely or together with
dendrimber and hyperbranched polymer of another kind.
[0044] As the hyperbranched polymer, for example, Viscoat #1000
manufactured by OSAKA ORGANIC CHEMICAL INDUSTRY LTD. is
available.
[0045] The addition amount of the dendritic polymer is preferably 3
to 30% by weight and more preferably 5 to 25% by weight. If the
addition amount of the dendritic polymer is less than 3% by weight,
the film quality after curing is insufficient, and if the addition
amount of the dendritic polymer is greater than 30% by weight, the
storage stability of the ink composition becomes worse.
[0046] The monomer used in the present embodiment is vinyl ether
group-containing (meth)acrylic acid esters expressed by the
following formula.
CH.sub.2.dbd.CR.sup.1--COO--R.sup.2--O--CH.dbd.CH--R.sup.3 (1)
[0047] (R.sup.1 denotes a hydrogen atom or a methyl group, R.sup.2
denotes an organic residue having a carbon number of 2 to 20, and
R.sup.3 denotes a hydrogen atom or an organic residue having a
carbon number of 1 to 11).
[0048] The monomer of one kind may be used solely or together with
vinyl ether group-containing (meth)acrylic acid esters.
[0049] As the organic residue having the carbon number of 2 to 20
expressed by R.sup.2 in the general formula (1), an alkylene group
having a straight chain shape, a branch shape or an annular shape
and having a carbon number of 2 to 20, an alkylene group having a
carbon umber of 2 to 20 and having oxygen atoms an ester bond
and/or an ester bond in the structure, and a substitutable aromatic
group having a carbon number of 6 to 11 are suitable. Of these, an
alkylene group having a carbon number of 2 to 6 or an alkylene
group having a carbon number of 2 to 9 and having hydrogen atoms by
an ether bond in the structure are suitably used.
[0050] As the organic residue having the carbon number of 1 to 11
expressed by R.sup.3 in the general formula (1), an alkyl group
having a straight chain shape, a branch shape or an annular shape
and having a carbon number of 1 to 10 and a substitutable aromatic
group having a carbon number of 6 to 11 are suitable. Of them, an
alkyl group having a carbon number of 1 to 2 and an aromatic group
having a carbon number of 6 to 8 are suitably used.
[0051] The monomer expressed by the general formula (1) includes
2-vinyloxyethyl(meth)acrylate, 3-vinyloxypropyl(meth)acrylate,
1-methyl-2-vinyloxyethyl(meth)acrylate,
2-vinyloxypropyl(meth)acrylate, 4-vinyloxybutyl(meth)acrylate,
1-methyl-3-vinyloxypropyl(meth)acrylate,
1-vinyloxymethylpropyl(meth)acrylate,
2-methyl-3-vinyloxypropyl(meth)acrylate,
3-methyl-3-vinyloxypropyl(meth)acrylate,
1,1-dimethyl-2-vinyloxyethyl(meth)acrylate,
3-vinyloxybutyl(meth)acrylate,
1-methyl-2-vinyloxypropyl(meth)acrylate,
2-vinyloxybutyl(meth)acrylate, 4-vinyloxycyclohexyl(meth)acrylate,
5-vinyloxypentyl(meth)acrylate, 6-vinyloxyhexyl(meth)acrylate,
4-vinyloxymethylcyclohexylmethyl(meth)acrylate,
p-vinyloxymethylphenylmethyl(meth)acrylate,
2-(vinyloxyethoxy)ethyl(meth)acrylate,
2-(vinyloxyisopropoxy)ethyl(meth)acrylate,
2-(vinyloxyethoxy)propyl(meth)acrylate,
2-(vinyloxyethoxy)isopropyl(meth)acrylate,
2-(vinyloxyisopropoxy)propyl(meth)acrylate,
2-(vinyloxyisopropoxy)isopropyl(meth)acrylate,
2-(vinyloxyethoxyethoxy)ethyl(meth)acrylate,
2-(vinyloxyethoxyisopropoxy)ethyl(meth)acrylate,
2-(vinyloxyethoxyisopropoxy)propyl(meth)acrylate,
2-(vinyloxyisopropoxyethoxy)propyl(meth)acrylate,
2-(vinyloxyethoxyethoxy)isopropyl(meth)acrylate,
2-(vinyloxyethoxyisopropoxy)isopropyl(meth)acrylate,
2-(vinylethoxyethoxyethoxy)isopropyl(meth)acrylate, polyethylene
glycol monovinyl ether(meth)acrylate, and polypropylene glycol
monovinyl ether(meth)acrylate.
[0052] Of these, from the viewpoint of low viscosity, a high flash
point, excellent curing properties,
2-(vinyloxyethoxy)ethyl(meth)acrylate, that is,
2-(vinyloxyethoxy)ethyl acrylate (VA), and 2-(vinyloxyethoxy)ethyl
methacrylate (VM) are suitable. The VA is more excellent than the
VM in view of the curing properties.
[0053] As a method of manufacturing the monomer, a method of
esterfying (meth)acrylate and hydroxyl group-containing vinyl
ethers (method A), a method of esterfying (meth)acrylate halide and
hydroxyl group-containing vinyl ethers (method B), a method of
esterfying (meth)acrylate anhydride and hydroxyl group-containing
vinyl ethers (method C), a method of ester-exchanging
(meth)acrylate esters and hydroxyl group-containing vinyl ethers
(method D), a method of esterfying (meth)acrylate and
halogen-containing vinyl ethers (method E), and a method of
esterfying alkali(earth)metal salts and halogen-containing vinyl
ethers (method F) are suitable. Of these, a method of
ester-exchanging (meth)acrylate esters and hydroxyl
group-containing vinyl esters (method D) is very suitable and the
operation and the effect of the present embodiment are more
sufficiently achieved.
[0054] The addition amount of the monomer is preferably 20 to 90%
by weight and more preferably 30 to 80% by weight in the ink
composition.
[0055] As the photopolymerization initiator, a material having
sensitivity with respect to an irradiated active ray, for example,
an ultraviolet ray of 400 to 200 nm, a far-infrared ray, a g-ray, a
h-ray, an i-ray, a KrF excimer laser light beam, an ArF excimer
laser light beam, an electron ray, an X-ray, a molecular beam, or
an ion beam may be selectively used.
[0056] As the photopolymerization initiator, the material which is
known to those skilled in the art may be used. Specific examples
thereof are described, for example, in Bruce M. Monroe et al.,
Chemical Revue, 93, 435 (1993); R, S. Davidson, Journal of
Photochemistry and biology, A: Chemistry, 73, 81 (1993); J. P.
Faussier, "Photoinitiated Polymerization-Theory and Applications":
Rapra Review vol. 9, Report, Rapra Technology (1998); and M.
Tsunooka et al., Prog. Polym. Sci., 21, 1 (1996). Many compounds
favorably used in chemical-amplification photoresists and for
photo-cation-polymerization are also described in Japanese Research
Association for Organic Electronics Materials Ed., "Organic
Materials for Imaging" (published by Bun-Shin Shuppan (1993), pp.
187 to 192). The compounds that undergo oxidative or reductive bond
cleavage through the interaction with the electronically-excited
state of sensitizing dye are also known, and described, for example
in F. D. Saeva, Topics in Current Chemistry, 156, 59 (1990); G. G.
Maslak, Topics in Current Chemistry, 168, 1 (1993); H. B. Shuster
et al., JACS, 112, 6329 (1990); I. D. F. Eaton et al., JACS, 102,
3298 (1980).
[0057] Preferable photopolymerization initiator includes (a)
aromatic ketones, (b) aromatic onium salt compounds, (c) organic
peroxides, (d) hexaarylbiimidazole compounds, (e) ketoxime ester
compounds, (f) borate compounds, (g) azinium compounds, (h)
metallocene compounds, (i) active ester compounds, and (j)
compounds containing a carbon-halogen bond. More preferably, the
photo-polymerization initiator is obtained by one kind or two or
more kind of .alpha.-aminoketone, .alpha.-hydroxyketone, and
acylphosphine oxide.
[0058] As the initiator, photo-polymerization initiators which are
commercially available as trade names of VICURE 10 and 30
(manufactured by Stauffer Chemical), Irgacure 127, 184, 500, 651,
2959, 907, 369, 379, 754, 1700, 1800, 1850, 1870, 819, OXE01,
Darocurl 1173, TPO, ITX (manufactured by Ciba Specialty Chemicals),
Quantacure CTX (manufactured by Aceto Chemical), Kayacure DETX-S
(manufactured by Nippon Kayaku Co. Ltd.), and ESACURE KIP150
(manufactured by Lamberti) can be used.
[0059] The addition amount of the polymerization initiator is
preferably 1 to 20% by weight and more preferably 2 to 10% by
weight in the ink composition.
[0060] In the composition according to the present embodiment, a
coloring material which can be generally used in the ink may be
used without special limitation. The color material may include a
pigment and a dye. In particular, as the coloring material used in
this case, the pigment is advantageous in the durability of a
printed material.
[0061] As the dye, various types of dyes used for ink jet recording
such as a direct dye, an acid dye, a food dye, a basic dye, a
reactive dye, a dispersive dye, a vat dye, a soluble vat dye, and a
reactive dispersive dye may be used.
[0062] As the pigment, an organic pigment or an inorganic pigment
may be used without special limitation.
As the inorganic pigment, in addition to titanium oxide and iron
oxide, carbon black manufactured by known methods such as a contact
method, a furnace method and a thermal method may be used. As the
organic pigment, azo pigments (including azo lake pigment,
insoluble azo pigment, condensed azo pigment, chelate azo pigment),
polycyclic pigments (for example, phthalocyanine, perylene,
perinone, anthraquinone, quinacridone, dioxazine, thioindigo,
isoindolinone, and quinophthalone pigments), dye chelates (for
example, basic dye chelates and acid dye chelates), nitro pigments,
nitrosopigments, and aniline black may be used.
[0063] As the detailed examples of the pigment, the examples of the
carbon black include C.I. Pigment Black 7; No. 2300, No. 900,
MCF88, No. 33, No. 40, No. 45, No. 52, MA7, MA8, MA100, No. 2200B,
and so forth made by Mitsubishi Chemical Corporation; Raven 5750,
5250, 5000, 3500, 1255, 700, and so forth made by Columbia; Regal
400R, 330R, and 660R, Mogul L and 700, Monarch 800, 880, 900, 1000,
1100, 1300, and 1400, and so forth made by Cabot; Color Black FW1,
FW2, FW2V, FW18, and FW200, Color Black S150, S160, and 5170,
Printex 35, U, V, and 140U, Special Black 6, 5, 4A, and 4, and so
forth made by Degussa.
[0064] The examples of the pigment used in a yellow ink include C.
I. pigment yellow 1, 2, 3, 12, 13, 14, 16, 17, 73, 74, 75, 83, 93,
95, 97, 98, 109, 110, 114, 120, 128, 129, 138, 150, 151, 154, 155,
180, 185 and 213.
[0065] The examples of the pigment used in a magenta ink include C.
I. pigment red 5, 7, 12, 48(Ca), 48(Mn), 57(Ca), 57:1, 112, 122,
123, 168, 184, 202, 209 and C. I. pigment violet 19.
[0066] The examples of the pigment used in a cyan pigment include
C. I. pigment blue 1, 2, 3, 15:3, 15:4, 60, 16 and 22.
[0067] According to the preferable embodiment of the present
embodiment, the average particle diameter of the pigment is
preferably in a range from 10 to 200 nm and more preferably a range
from 50 to 150 nm. The addition amount of the coloring material in
the ink composition is preferably in a range from 0.1 to 25% by
weight and more preferably 0.5 to 15% by weight.
[0068] If the ink composition includes the coloring material, there
are a plurality of ink compositions including respective coloring
materials. For example, if colors lighter or darker than the
respective colors are added in addition to four basic colors such
as yellow, magenta, cyan and black, light magenta lighter than
magenta, red darker than the magenta, light cyan lighter than cyan,
blue darker than cyan, gray and light black lighter than black, and
a mat black darker than black may be used.
[0069] If the pigment is used as the coloring material, it is
preferable that a dispersant is added to the ink composition. As
the dispersant, for example, polyoxyalkylenepolyalkylenepolyamine
(C.sub.2H.sub.4nN).sub.n--(PO).sub.x-(EO).sub.y--OH (in this
formula, n, x and y denote integers of 1 or more, PO denotes
propylene oxide, and EO denotes ethylene oxide) may be used. The
detailed examples of polyoxyalkylenepolyalkylenepolyamine include,
for example, Discole N-503, N-506, N-509, N-512, N-515, N-518 and
N-520.
[0070] The addition amount of the dispersant is preferably 0.1 to
20% by weight and more preferably 0.5 to 10% by weight.
[0071] Other additive agents may be added to the photo-curable ink
composition according to the present embodiment, if necessary.
[0072] As the additive agent, a material selected from a
polymerization promoter, a resin emulsion, a wetting agent, a pH
adjuster, a surfactant, an antiseptic agent and a mildew-proofing
agent may be added, if necessary. One kind or two or more kinds of
these components may be used. The additive agent may not be added,
if necessary. Preferable amounts of preferable additive agents may
be used in a range which the effect of the invention does not
deteriorate.
[0073] The ink composition of the present embodiment is
manufactured by including the components properly selected from the
above-described components, but the viscosity of the ink
composition which can be obtained is preferably less than 25 mPas
at 20.degree. C. In the present embodiment, the surface tension of
the ink composition is preferably equal to or less than 45 mN/m at
20.degree. C. and more preferably in a range of 25 to 45 mN/m. By
adjusting the viscosity and the surface tension, it is possible to
obtain an ink composition having preferable characteristics so as
to be used in an ink jet recording method. The adjustment of the
viscosity and the surface tension is performed by properly
adjusting the addition amount of the monomer included in the ink
composition.
[0074] As a method of manufacturing the ink composition, a method
of mixing and uniformly dissolving various kinds of components
included in the ink composition, pressurizing and filtering the
components by a membrane filter having a hole diameter of 0.8
.mu.m, and deaerating an additionally obtained solution using a
vacuum pump so as to manufacture the ink composition may be used
and is not limited thereto.
[0075] The above-described photocurable ink composition is used as
the ink cartridge in which one kind or two or more kinds of
photo-curable ink composition is integrally or independently
received. Accordingly, it is possible to facilitate the treatment
of the ink composition. The ink cartridge including the ink
composition is known in the present technical field and may be used
as the ink cartridge using properly the known method.
[0076] The ink cartridge may be used for a general writing
instrument, a recording system, and a pen plotter, but is more
preferably used for an ink jet recording method.
[0077] Ink Jet Recording Method
[0078] In the ink jet recording method according to the present
embodiment, the photocurable ink composition having the
above-described composition is discharged onto a recording medium,
an ultraviolet ray is irradiated onto, and liquid droplets are
cured.
[0079] As the recording medium, various recording mediums such as
plain paper, ink jet dedicated paper (mat paper or glossy paper),
glass, plastic, film, metal printed board may be used without
special limitation.
[0080] The preferable conditions of the irradiation of the
ultraviolet ray are properly selected by the amount or the
thickness of the ink composition attached to the board or the
recording medium. Accordingly, the conditions cannot be strictly
specified, but, for example, the wavelength of the light irradiated
from a light irradiating apparatus is preferably in a range of 350
to 450 nm.
[0081] The irradiation amount of the ultraviolet ray is in a range
from 10 mJ/cm.sup.2 to 10,000 mJ/cm.sup.2 and preferably 50
mJ/cm.sup.2 to 6,000 mJ/cm.sup.2. If the ultraviolet ray is
irradiated in this range, the curable reaction of the photo-radical
curable ink composition can be sufficiently performed.
[0082] The irradiation of the ultraviolet ray may be accomplished
by a metal halide lamp, a xenon lamp, a carbon arc lamp, a chemical
lamp, a low pressure mercury vapor lamp, a high pressure mercury
vapor lamp, and other such lamps. For example, a commercially
available source such as an H lamp, D lamp, or V lamp made by
Fusion System can be used.
[0083] The irradiation of the ultraviolet ray can also be
accomplished by using an ultraviolet ray light emitting diode (UV
LED), an ultraviolet ray light emitting semiconductor laser, or
other such ultraviolet ray light emitting semiconductor element, in
order to reduce energy consumption.
[0084] The examples of the method of discharging the photo-curable
ink composition include the following methods. A first method is a
method called an electrostatic suction method. The electrostatic
suction method is a method of applying a strong ampere meter
between acceleration electrodes disposed on the front sides of the
nozzles, continuously ejecting ink droplets from the nozzles,
applying print information signals to deflection electrodes while
the ink droplets pass between the deflection electrodes, flying the
ink droplets toward a recording medium, fixing the ink onto the
recording medium, and recording an image or a method of ejecting
ink droplets from nozzles onto a recording medium according to a
print information signal and fixing and recording an image on the
recording medium.
[0085] A second method is a method of applying pressure to an ink
solution by a small-sized pump, mechanically vibrating ink jet
nozzles by a crystal oscillator and forcedly ejecting ink droplets
from the nozzles or a method of ejecting and charging ink droplets
ejected from nozzles, applying print information signals to
deflection electrodes while the ink droplets pass between the
deflection electrodes, flying the ink droplets toward a recording
medium, and recording an image on the recording medium.
[0086] A third method is a method of applying pressure and print
information signals to an ink solution by a piezoelectric element,
ejecting ink droplets from nozzles onto a recording medium, and
recording an image on the recording medium.
[0087] A fourth method is a method of heating and foaming an ink
solution using minute electrodes according to print information
signals, expanding air bubbles, ejecting the ink solution from
nozzles onto a recording medium, and recording an image on the
recording medium.
[0088] Recorded Material
[0089] In a recorded material according to the present embodiment,
recording is performed by an ink jet recording method using the
photocurable ink composition. Since the recorded material is
obtained by the ink jet recording method using the above-described
photo-curable ink composition, printing quality is excellent,
printing stability is excellent, a beautiful chromogenic state is
obtained, and the chromogenic state can be maintained for a long
period of time.
Embodiment A
[0090] Hereinafter, the following embodiments of the invention will
be described in detail, but the invention is not limited to the
embodiments.
[0091] The ink composition shown in Table 1 was manufactured by a
general method.
TABLE-US-00001 TABLE 1 Embodiment Comparative Example 1 2 3 4 5 6 7
8 1 2 3 4 Monomer VA 69.6 -- 64.2 74.8 82.6 53.6 54.6 81.6 -- -- --
84.8 VM -- 69.6 -- -- -- -- -- -- -- -- -- -- Isobornyl -- -- -- --
-- -- -- -- 69.6 -- -- -- acrylate Isobutyl -- -- -- -- -- -- -- --
-- 69.2 -- -- acrylate t-butyl -- -- -- -- -- -- -- -- -- -- 69.6
-- acrylate Hyperbranched polymer 15 15 20 10 2 31 30 3 15 15 15 --
(viscoat 1000) Irgacure819 6 -- -- 6 6 6 -- 6 -- -- -- --
Irgacure1870 -- 6 6 -- -- -- 6 -- 6 6 6 6 Irgacure127 2 2 2 2 2 2 2
2 2 2 2 2 Pigment black -7 6 -- -- -- -- 6 6 6 -- -- 6 -- Pigment
blue -15:3 -- 6 -- -- -- -- -- -- 6 -- -- -- Pigment violet -19 --
-- 6 -- -- -- -- -- -- 6 -- -- Pigment yellow - 155 -- -- -- 6 --
-- -- -- -- -- -- 6 Dispersant (polyoxy 1.4 1.4 1.8 1.2 1.4 1.4 1.4
1.4 1.4 1.8 1.4 1.2 alkylene polyalkylene polyamine) In the table,
the details of the components are as follows. VA:
2-(vinyloxyethoxy)ethyl acrylate included in the general formula
(1) VM: 2-(vinyloxyethoxy)ethyl isobornyl acrylate Isobutylacrylate
included in the general formula (1), t-butylacrylate: the monomer
which is not included in the general formula (1) Viscoat 1000
(manufactured by OSAKA ORGANIC CHEMICAL INDUSTRY LTD.):
hyperbranched polymer Irgacure819, Irgacure1870, Irgacure127 (all
of them are manufactured by Ciba Specialty Chemicals K.K.):
polymerization initiator
[0092] The ink compositions of Embodiments 1 to 8 and Comparative
Examples 1 to 4 shown in Table 1 were evaluated with respect to the
following list.
[0093] Film Curing Properties
Inks described in Embodiments and inks described in Comparative
Examples were charged in RED nozzle arrays using an ink jet printer
PX-G920 (manufactured by Seiko Epson Corporation). Under normal
pressure, RED solid patterns (720.times.720 dots were printed per
square inch at 10 ng of one dot) were printed on a PET film (an
actually printed color is an ink color charged in RED nozzle
arrays). Thereafter, ultraviolet rays having wavelengths of 365 nm,
380 nm and 395 nm were irradiated from an ultraviolet ray
irradiating apparatus having an irradiation intensity of 150
mW/cm.sup.2. When touch feeling of the sample surface is lost, it
is determined that curing is accomplished. The curing properties
were evaluated according to the following indexes.
[0094] AA: curing is accomplished by the irradiation for 1
minute
[0095] A: curing is accomplished by the irradiation for 3
minutes
[0096] B: curing is not accomplished by the irradiation for 5
minutes
[0097] Film Strength
[0098] The samples printed by the above-described method were cured
by the ultraviolet rays using the same irradiating apparatus for 10
minutes. Just after curing, the film strengths were evaluated by
the following indexes.
[0099] A: The surface is not scratched by a fingernail.
[0100] B: The surface is scratched by a fingernail.
[0101] Film Quality
[0102] The samples printed by the above-described method were cured
by the ultraviolet rays using the same irradiating apparatus for 10
minutes. After curing, the samples were left under normal
temperature and normal pressure for three days and the film
qualities of the samples were observed and evaluated by the
following indexes.
[0103] AA: The warpage of the film is not observed due to the film
curing shrinkage.
[0104] A: The warpage of the film is observed by less than 3 cm due
to the film curing shrinkage.
[0105] B: The warpage of the film is observed by 3 cm or more due
to the film curing shrinkage.
[0106] Storage Stability
[0107] The ink compositions of Embodiments 1 to 8 and Comparative
Examples 1 to 4 were left under an environment of 60.degree. C. for
5 days and the initial viscosities (mPas) thereof and the
viscosities thereof after being left were measured by a Rheometer
(manufactured by Physica, MCR-300), and viscosity variation ratios
were evaluated by the following indexes.
[0108] AA: The variation ratio of the initial viscosity to the
viscosity after being left is .+-.10% or less.
[0109] A: The variation ratio of the initial viscosity to the
viscosity after being left is .+-.20% or less.
[0110] B: The variation ratio of the initial viscosity to the
viscosity after being left is greater than .+-.20%.
[0111] Flash Point
[0112] The flash points of the manufactured inks were measured
using a Setaflash Closed Cup type flash point measurement device
(Model. 13740-2 Tanaka Scientific Limited) and the flash points
were evaluated by the following indexes.
[0113] A: 70.degree. C. or more
[0114] B: less than 70.degree. C.
[0115] The result of evaluating the film curing properties, the
film strengths, the film qualities, the storage stabilities, and
the flash points is shown in Table 2.
TABLE-US-00002 TABLE 2 Embodiment Comparative Example 1 2 3 4 5 6 7
8 1 2 3 4 Film curing properties AA A AA AA AA AA AA AA B B B AA
Film strength A A A A A A A A A A A B Film quality AA AA AA AA A AA
AA AA AA AA AA B Storage stability AA AA AA AA AA A AA AA B -- --
AA Flash point A A A A A A A A A B B A
Embodiment B
[0116] Next, the film curing properties of several embodiments and
comparative examples used in Embodiment A were evaluated with
respect to several irradiating conditions. Table 3 shows the ink
compositions used in Embodiment B. The numbers of the embodiments
and the comparative examples correspond to those of Table 1. In
Embodiment B, Embodiment 9, Comparative Examples 5 and 6, and
Reference Examples 1 and 2 were added. In Embodiment 9, aminoketone
(Irgacure369) is used as the photopolymerization initiator. In
Comparative Examples 5 and 6, the hyperbranched polymer is not
included. More in detail, Comparative Example 5 is the ink
composition having the composition similar to International
Unexamined Patent Application Publication No. WO03/089486 and
Comparative Example 6 is the ink composition including a
pre-polymer (curable resin 1) disclosed in the same publication. In
Reference Examples 1 and 2, arylglycol and vinylether having
excellent characteristics as an ink jet monomer are used similar to
the VA.
[0117] The curable resin 1 of Table 3 was manufactured according to
"resin synthesis example 4" of the best mode for carrying out the
invention of the same publication. That is, in a 4-port flask of 1
L including an agitator, a thermometer, a rectification tower and a
gas introduction pipe, 108 parts of acrylate, 750 parts of
saturated polyesterpolyol resin (oligoester obtained by condensing
4-mol diethyleneglycol and 3-mol adipic acid: acid value is 3 and
hydroxyl is 150), 24 parts of paratoluenesulfonic acid and 300
parts of toluene were added, azeotropic dehydration was performed
under air stream at 115.degree. C. for 10 hours, the internal
temperature was cooled to a room temperature, cleaning was
performed in 800 parts of a saturated sodium hydrogen carbonate
aqueous solution two times and in 800 parts of deionized water,
evaporation and dry were performed under the reduced pressure of
1,333 kPa at 90.degree. C. for 5 hours, and polyestermethacrylate
was obtained. The obtained polyestermethacrylate was curing resin
1.
TABLE-US-00003 TABLE 3 Reference Comparative Embodiment Example
Example 1 3 4 9 1 2 1 5 6 Monomer VA 69.6 64.2 74.8 69.6 -- -- --
74.1 69.6 arylglycol -- -- -- -- 64.2 -- -- -- -- 4-hydroxybutyl --
-- -- -- -- 64.2 -- -- vinylether Isobornyl acrylate -- -- -- -- --
-- 69.6 -- -- Diethyleneglycol -- -- -- -- -- -- -- 0.24 --
monovinylether Diethyleneglycol -- -- -- -- -- -- -- 1.06 --
divinylether Diethyleneglycol -- -- -- -- -- -- -- 0.1 --
diacrylate trimethylolpropane -- -- -- -- -- -- -- 10 --
triacrylate Hyperbranched polymer 15 20 10 15 20 20 15 -- --
(viscoat 1000) Curing resin 1 -- -- -- -- -- -- -- -- 15
Irgacure819 6 -- 6 -- -- -- -- 6 6 Irgacure1870 -- 6 -- -- 6 6 6 --
-- Ircacure127 2 2 2 2 2 2 2 2 2 Ircacure369 -- -- -- 6 Pigment
black -7 6 -- -- 6 -- -- -- 6 6 Pigment blue -15:3 -- -- -- -- --
-- 6 -- -- Pigment violet -19 -- 6 -- -- 6 6 -- -- -- Pigment
yellow -155 -- -- 6 -- -- -- -- -- -- Dispersant (polyoxy 1.4 1.8
1.2 1.4 1.8 1.8 1.4 1.4 1.4 alkylene polyalkylene polyamine)
[0118] The film curing properties were tested as follows.
[0119] Film Curing Properties
[0120] Using an ink jet printer PX-G920 (manufactured by Seiko
Epson Corporation), the inks described in Embodiments, Reference
Examples, and Comparative Examples are charged in a RED nozzle
array. Under normal pressure, RED solid patterns (720.times.720
dots were printed per square inch at 10 ng of one dot) were printed
on a PET film (an actually printed color is an ink color charged in
RED nozzle arrays). Thereafter, ultraviolet rays having wavelengths
of 365 nm, 380 nm and 395 nm were irradiated from an ultraviolet
ray irradiating apparatus. An irradiation intensity is adjusted to
20, 40, 70, 100, 150 and 200 mW/cm.sup.2. When touch feeling of the
sample surface is lost, it is determined that curing is
accomplished. The curing properties were evaluated according to the
following indexes.
[0121] AAA: curing is accomplished by the irradiation of less than
45 seconds
[0122] AA: curing is accomplished by the irradiation of 45 to 90
seconds
[0123] A: curing is accomplished by the irradiation of 90 to 180
seconds
[0124] B: curing is accomplished by the irradiation of 180 seconds
to 540 seconds
[0125] C: curing requires the irradiation of 540 seconds or
more
[0126] The result of evaluating the film curing properties is shown
in Table 4.
TABLE-US-00004 TABLE 4 Reference Comparative Embodiment Example
Example 1 3 4 9 1 2 1 5 6 200 mW/cm.sup.2 AAA AAA AAA AAA AA A B AA
AA 150 mW/cm.sup.2 AAA AAA AAA AAA AA A B AA AA 100 mW/cm.sup.2 AAA
AAA AAA AAA AA A B AA AA 70 mW/cm.sup.2 AAA AAA AAA AAA AA A B B B
40 mW/cm.sup.2 B B B B B B C B B 20 mW/cm.sup.2 C C C C B B C C C
Film strength A A A A A A A B A Film quality AA AA AA AA AA AA AA B
B
[0127] In the ink composition of the present embodiment, it can be
seen that excellent curing properties can be accomplished in a
region in which the irradiation amount of the ultraviolet ray is 70
mW/cm.sup.2. Reference Examples 1 and 2 are characterized in that
the dependence on the irradiation intensity is low. The
characteristic is inferior to the VA at a high illumination
intensity but is superior to the VA at a low illumination
intensity. Generally, if dots are formed by small liquid droplets,
a curing failure is susceptible to occur due to oxygen inhibition,
but, in the above embodiment, a good result was obtained in the
liquid droplet unit of 10 ng.
[0128] The invention has industrial availability as a photo-curable
ink composition which is excellent in storage stability, stability,
curing properties, and film quality after curing, an ink jet
recording method using the same, and a recorded material.
* * * * *