JP7293925B2 - Cationically polymerizable color ink composition, ink set, and laminate for flexographic printing - Google Patents

Description

The present invention provides a cationic polymerizable color ink composition for flexographic printing used for adhesive labels, an ink set for adhesive labels comprising the cationic polymerizable color ink composition for flexographic printing and a polymerizable clear ink composition, and the It relates to a laminate using an ink set.

In recent years, supermarkets have been using portable auto-labelers and hand-labelers to automatically feed adhesive label sheets one by one and attach special price labels such as time sales to paper containers and products wrapped in plastic film. It's getting more and more attached. Adhesive label paper used for portable auto labelers and hand labelers is printed with a conspicuous ink layer on the surface of the base material, such as wood-free paper or coated paper, and the back side is subjected to adhesive (pressure-sensitive adhesive) processing. It is rolled into a roll. Adhesive label paper has a separator such as release paper or plastic film overlaid on the adhesive surface so that the adhesive layer (back) and the front surface can be peeled off (not adhered) smoothly. Therefore, since the separator is peeled off and discarded when the label is used, a method of not using the separator has been investigated from the viewpoint of environment and cost.

For example, Japanese Patent Publication No. 03-128975 discloses a UV-curable epoxysilicone/polyol-based release composition, wherein a silicone composition based on polyorganosiloxane is
Since it has releasability against sticky substances, by coating the surface of paper, plastic film, etc. and providing a release layer, adhesion on the back surface can be suppressed, eliminating the need for a separator. As silicone compositions used for such release layers, heat-curable and ultraviolet-curable silicone compositions are known. Various studies have been made on the ultraviolet-curing type because it cures instantaneously by irradiation with ultraviolet rays, saves energy and requires less equipment than the heat-curing type.

Furthermore, UV-curable silicone compositions are radically polymerizable,
There are hydrosilylation reaction type and cationic polymerization type. Among them, the cationic polymerization type has been widely used because it is not affected by oxygen during curing unlike the radical polymerization type, the shrinkage of the coating film after curing is small, and the release performance is easy to control.

However, the cationically polymerizable UV-curable silicone composition does not cure sufficiently due to the amine compounds and basic compounds contained in the plastic film and synthetic paper used as the substrate, resulting in unsatisfactory release performance. and the cationic polymerizable UV-curable silicone composition have a problem of poor adhesion. Similarly, when a cationic polymerizable UV-curable silicone composition is applied onto an ink layer, there is a problem that the composition is greatly affected by substances contained in the ink. For example, in recent years, when radically polymerizable curable offset inks containing pigments, which have been used more and more because of their quick-drying properties and high productivity, are used in the ink layer, they are added for the purpose of improving the curability of the ink. Amine compounds and basic compounds such as basic dispersants used as pigment dispersants interfere with the curing of the cationic polymerizable UV-curable silicone composition, resulting in a problem that satisfactory release performance cannot be obtained. rice field.

There is also a problem that the compound contained in the adhesive layer migrates to the ink layer through the release layer, resulting in a decrease in adhesion between the ink layer and the substrate layer over time.

In order to solve such problems, for example, Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2002-240203
) discloses a release substrate having a filler layer made of a UV-curable filler between the substrate and a cationic polymerizable UV-curable silicone release agent. However, when the ink layer is printed with a radically polymerizable curable ink using a basic compound such as an amine compound or a basic dispersant, there is a problem that a sufficient effect cannot be obtained. When the amine compound is removed from the radically polymerizable curable ink, the curability of the cationically polymerizable UV-curable silicone composition is improved. There is also a problem that poor curing occurs due to hindrance to permeation. Furthermore, in Patent Document 1, no consideration is given to poor adhesion caused by compounds migrating from the adhesive layer.

In addition, when the ink used for the ink layer is for offset printing, complicated work such as adjusting the amount of ink and the amount of water is required during printing, and there is a problem in productivity. Therefore, compared to offset printing, the ink layer does not require complicated work, and the printing cost is relatively low. There has been a demand for flexographic printing that can use recording media. Further, there is a demand for an ultraviolet curable flexographic ink that does not require a drying step to remove organic solvents and water and has high productivity.

Examples of ultraviolet curable flexographic inks include those disclosed in Patent Document 2 (Japanese Unexamined Patent Application Publication No. 2007-2325
6) discloses an active energy ray-curable flexographic ink containing an oxetane compound, a vinyl ether compound, or an epoxy compound. However, since basic compounds such as basic dispersants and amine compounds are used, it is not possible to solve the problem of poor curing of cationic polymerizable UV-curable silicone compositions. do not have.

Japanese Patent Application Laid-Open No. 2002-240203 JP 2007-23256 A

The problem to be solved by the present invention is to have a coating film physical properties (adhesion, flexibility) necessary for an adhesive label without hindering the curability of the cationically polymerizable silicone composition used as a release agent, and to Provided are a cationic polymerizable color ink for flexographic printing having printability, an ink set for adhesive labels comprising the cationic polymerizable color ink composition for flexographic printing and a polymerizable clear ink composition, and a laminate using them. is.

The present inventors have made intensive studies to solve the above problems, and as a result, the following cationic polymerizable UV-curable color ink composition for flexographic printing, the cationic polymerizable color ink composition for flexographic printing, and polymerizable clear The inventors have found that the above problems can be solved by an ink set for adhesive labels with an ink composition, and have completed the present invention.

That is, the present invention provides a cationic polymerizable color ink composition for flexographic printing comprising a colorant, a cationic polymerization initiator, and a cationic polymerizable compound,
The cationically polymerizable compound contains an epoxy compound (A) having a bisphenol A structure, an alicyclic epoxy compound (B) (except when it becomes (A)), and an oxetane compound (C),
The content of the epoxy compound (A) is 5 to 20% by mass with respect to the total mass of the color ink composition,
The content of the alicyclic epoxy compound (B) is 10 to 50% by mass with respect to the total mass of the color ink composition,
The content of the oxetane compound (C) is 10 to 30% by mass with respect to the total mass of the color ink composition,
The epoxy compound (A) has a weight average molecular weight of 400 to 2,000,
The present invention relates to a cationic polymerizable color ink composition for flexographic printing, which is characterized by being substantially free of basic compounds.

The present invention also relates to the cationic polymerizable color ink composition for flexographic printing, wherein the alicyclic epoxy compound (B) has an epoxy equivalent of 110-250.

The present invention also relates to the cationic polymerizable color ink composition for flexographic printing, wherein the oxetane compound (C) has one oxetane ring and one hydroxyl group in its structure.

The present invention also relates to a polymerizable ink set for adhesive labels, comprising the cationic polymerizable color ink composition for flexographic printing and the polymerizable clear ink composition.

In addition, the present invention further comprises a cationically polymerizable silicone composition as a release agent,
The polymerizable ink set for adhesive labels is characterized in that the cationic polymerizable silicone composition contains a cationic polymerization initiator and a polyorganosiloxane compound having an epoxy group.

In addition, the present invention provides a base material having an adhesive layer on one side thereof, on the side opposite to the adhesive layer, the polymerizable ink set for adhesive labels, the cationic polymerizable color ink composition for flexographic printing, and the polymerizable clear ink. The present invention relates to a pressure-sensitive adhesive label laminate characterized by laminating a composition and a cationically polymerizable silicone composition in this order.

According to the present invention, a cationic polymerizable color ink for flexographic printing that does not interfere with the curability of a cationic polymerizable silicone composition used as a release agent, has excellent adhesion to a substrate, and is suitable for flexographic printing; It was possible to provide an ink set for adhesive labels comprising the cationic polymerizable color ink composition for flexographic printing and the polymerizable clear ink composition, and a laminate using them.

DETAILED DESCRIPTION OF THE INVENTION Embodiments for carrying out the present invention will be described in detail below. It should be noted that the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the present invention.

<Cationic polymerizable UV-curable color ink for flexographic printing>
One embodiment of the present invention relates to a cationically polymerizable color ink composition for flexographic printing.
The cationic polymerizable color ink composition for flexographic printing comprises a colorant, a cationic polymerization initiator,
A cationic polymerizable color ink composition for flexographic printing containing a cationic polymerizable compound, wherein the cationic polymerizable compound is an epoxy compound (A) having a weight average molecular weight of 400 to 2,000 and a bisphenol A skeleton; It is characterized by containing an epoxy compound (B) (except when it becomes (A)) and an oxetane compound (C), and substantially not containing a basic compound.

Hereinafter, the cationic polymerizable color ink composition for flexographic printing of the present embodiment (hereinafter simply referred to as "
Ingredients that are or can be included in the color ink composition are described.

[Coloring agent]
The cationic polymerizable color ink for flexographic printing in the present invention contains a colorant. At least one of pigments and dyes can be used as the colorant. Pigments are preferred from the viewpoint of light resistance.
Pigments that can be used in the present invention are not particularly limited, and known pigments can be used. Both inorganic pigments and organic pigments can be used as the pigment.

Examples of the inorganic pigments include furnace black, lamp black, acetylene black,
Carbon blacks such as channel black, iron oxide, titanium oxide, etc.

Examples of the organic pigment include soluble azo pigments such as β-naphthol, β-oxynaphthoic acid, β-oxynaphthoic anilide, acetoacetic anilide, and pyrazolone; β-naphthol, β-oxynaphthoic acid insoluble azo pigments such as anilide-type, anilide-type acetoacetate-type monoazo, disazo-type acetoacetate-type, pyrazolone-type, etc.; Phthalocyanine-based pigments such as free phthalocyanine; quinacridone-based, dioxazine-based, threne-based (pyranthrone, anthanthrone, indanthrone, anthrapyrimidine, flavanthrone, thioindigo-based, anthraquinone-based, perinone-based, perylene-based, etc.), isoindolinone-based, Metal complex-based, quinophthalone-based, diketopyrrolopyrrole-based polycyclic pigments and heterocyclic pigments are included.
In the present specification, coloring agents do not include extender pigments such as barium sulfate, calcium carbonate, and aluminum hydroxide that do not have coloring power.

For more details, see C.I. I. In terms of color index, black pigments include C.I. I. Pi
gment Black 1, 6, 7, 9, 10, 11, 28, 26, 31 and the like.

As a white pigment, C.I. I. Pigment White 5, 6, 7, 12, 28 and the like.

As a yellow pigment, C.I. I. Pigment Yellow 1, 2, 3, 12, 13,
14, 16, 17, 18, 24, 73, 74, 75, 83, 93, 95, 97, 98, 1
00, 108, 109, 110, 114, 120, 128, 129, 138, 139, 1
74, 150, 151, 154, 155, 167, 180, 185, 213 and the like.

Blue or cyan pigments include C.I. I. Pigment Blue 1, 2, 14, 15
, 15:1, 15:2, 15:3, 15:4, 60, 62 and the like.

As a red or crimson pigment, C.I. I. Pigment RED 1, 3, 5, 19, 21,
22, 31, 38, 42, 43, 48:1, 48:2, 48:3, 48:4, 48:5,
49:1, 50, 52, 53:1, 57:1, 57:2, 58:4, 63:1, 81, 8
1:1, 81:2, 81:3, 81:4, 83, 90, 104, 108, 112, 114
, 122, 144, 146, 148, 149, 150, 166, 168, 169, 170
, 172, 173, 176, 177, 178, 184, 185, 187, 193, 202
, 209, 214, 242, 254, 255, 264, 266, 269, C.I. I. Pig
ment Violet 19 and the like.

As a green pigment, C.I. I. Pigment Green 1, 2, 3, 4, 7, 8, 1
0, 15, 17, 26, 36, 45, 50 and the like.

As a purple pigment, C.I. I. Pigment Violet 1, 2, 3, 4, 5:1,
12, 13, 15, 16, 17, 19, 23, 25, 29, 31, 32, 36, 37, 3
9, 42 and the like.
As an orange pigment, C.I. I. Pigment Orange 13, 16, 20,
34, 36, 38, 39, 43, 51, 61, 63, 64, 74 and the like.

In the present invention, the above pigments may be used singly or in combination of two or more.

In the present invention, the pigment can be used in any content as long as the desired density can be reproduced on the printed paper surface, and the content is 5 to 30% by mass with respect to the total mass of the color ink composition. preferably 10 to 25% by mass.

[Cationic polymerization initiator (hereinafter also referred to as "cationic initiator")]
The cationic polymerizable color ink for flexographic printing in the present invention contains a cationic polymerization initiator. A cationic polymerization initiator is a compound that can release a substance that initiates cationic polymerization by receiving energy rays such as light and ultraviolet rays.

In the present invention, the cationic polymerization initiator is not particularly limited, and known ones can be used. Specific examples include acid generators such as arylsulfonium salt derivatives, aryliodonium salt derivatives, allene-ion complex derivatives, diazonium salt derivatives, triazines and other halides. Among them, it is preferable to use an arylsulfonium salt derivative.

The above cationic polymerization initiators may be used singly or in combination of two or more.

In the present invention, the content of the cationic polymerization initiator is preferably 0.5 to 30% by mass, more preferably 5 to 20% by mass, based on the total mass of the color ink composition.

In the present invention, it is preferred that substantially no radical polymerization initiator is contained. In particular, it is preferred that substantially no radical polymerization initiator or radical polymerization initiation accelerator having an amino group is contained. Substantially free means that the content of the radical polymerization initiator is preferably 1.0% by mass or less, more preferably 0.1% by mass or less, relative to the total mass of the color ink composition.

[Cationically polymerizable compound]
The cationic polymerizable color ink for flexographic printing according to the present invention includes, as cationic polymerizable compounds, an epoxy compound (A) having a weight average molecular weight of 400 to 2,000 and having a bisphenol A structure, an alicyclic epoxy compound (B) (( A)), and the oxetane compound (C).

(Epoxy compounds having a bisphenol A structure with a weight average molecular weight of 400 to 2,000 (
A))
The epoxy compound (A) used in the present invention has at least a weight-average molecular weight (hereinafter also referred to as Mw) of 400 to 2,000, and a known epoxy compound having a bisphenol A structure can be used. can. Among them, Mw from the viewpoint of curability is 600 ~
1,200 is more preferred.

In the present specification, the weight average molecular weight is calculated from the structural formula when the weight average molecular weight can be specified from the structural formula, and when the weight average molecular weight cannot be specified from the structural formula, gel permeation chromatography (hereinafter , referred to as “GPC”).

A specific measurement method of GPC is as follows. HLC-8020 manufactured by Tosoh Corporation was used, and a calibration curve was prepared from standard polystyrene samples. Tetrahydrofuran was used as an eluent, and three columns of TSKgel Super HM-M (manufactured by Tosoh Corporation) were used. The measurement was performed at a flow rate of 0.6 ml/min, an injection volume of 10 µl, and a column temperature of 40°C.

In the present invention, the content of the epoxy compound (A) having a bisphenol A structure with a weight average molecular weight of 400 to 2,000 is preferably 5 to 20% by mass with respect to the total mass of the color ink composition. More preferably, it is 8 to 15% by mass. When the content is within the above range, components migrating from the adhesive layer can be suppressed without impairing the curability and flexographic printability of the color ink composition.

Furthermore, the epoxy equivalent of the epoxy compound (A) having a bisphenol A structure with a weight average molecular weight of 400 to 2,000 is 20 from the viewpoint of curability and suppression of component migration from the adhesive layer.
It is preferably 0 to 1,000, more preferably 400 to 800.

In addition, in this specification, the epoxy equivalent was measured based on JISK7236.

Specific examples of the epoxy compound (A) having a bisphenol A structure with a weight average molecular weight of 400 to 2,000 include jER1001 (Mw900, epoxy equivalent 450) and jER1002 (Mw1,200, epoxy equivalent 600) manufactured by Mitsubishi Chemical Corporation. ), jER
1003 (Mw 1,300, epoxy equivalent 450), jER1004 (Mw 1,650,
epoxy equivalent 875), jER1055 (Mw 1,600, epoxy equivalent 800), and the like.

In the present invention, the epoxy compound (A) having a bisphenol A structure and having a weight average molecular weight of 400 to 2,000 may be used alone or in combination of two or more.

(Alicyclic epoxy compound (B) (except when it becomes (A)))
In the present invention, the content of the alicyclic epoxy compound (B) is preferably 10 to 70% by mass, more preferably 30 to 50% by mass, relative to the total mass of the color ink composition.
is. When the content is within the above range, without impairing the curability of the color ink composition,
Flexographic printability can be obtained. In the present invention, the alicyclic epoxy compound is a compound having an epoxy group, which is a reactive group, on the alicyclic skeleton.

In the present invention, known compounds can be used as the alicyclic epoxy compound (B). Specific examples include 3,4-epoxycyclohexylmethyl-(3,4-epoxy)cyclohexanecarboxylate, 2-(3,4-epoxy)cyclohexyl-5,1-spiro(3,4-epoxy)cyclohexyl-meth -dioxane, bis(3,4-epoxycyclohexylmethyl)adipate, vinylcyclohexene oxide, 4-vinylepoxycyclohexane, bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate, 3,4-epoxy-6-methyl Cyclohexyl-(3,4-epoxy-6-methyl)cyclohexanecarboxylate, methylenebis(3,4-epoxycyclohexane)
, dicyclopentadiene diepoxide, di(3,4-epoxycyclohexylmethyl)ether of ethylene glycol, ethylenebis(3,4-epoxycyclohexanecarboxylate), lactone-modified 3,4-epoxycyclohexylmethyl-(3,4- epoxy) cyclohexane carboxylate, limonene monoxide, limonene dioxide, and the like. Among them, compounds having two alicyclic epoxy structures are preferable, and 3,4-epoxycyclohexylmethyl-(3,4-epoxy)cyclohexanecarboxylate is more preferable from the viewpoint of curability and flexographic printability.

In the present invention, the alicyclic epoxy compound (B) may be used singly or in combination of two or more.

(Oxetane compound (C))
In the present invention, the content of the oxetane compound (C) is preferably 10-30% by mass, more preferably 15-25% by mass, based on the total mass of the color ink composition.

A well-known thing can be used as said oxetane compound (C). Specifically, as compounds having one oxetane ring, 3-ethyl-3-hydroxymethyloxetane, 3-(meth)allyloxymethyl-3-ethyloxetane, 3-ethyl-3-(4-
Hydroxybutyloxymethyl)oxetane, (3-ethyl-3-oxetanylmethoxy)methylbenzene, 4-fluoro-[1-(3-ethyl-3-oxetanylmethoxy)methyl]benzene, 4-methoxy-[1-(3 -ethyl-3-oxetanylmethoxy)methyl]benzene, [1-(3-ethyl-3-oxetanylmethoxy)ethyl]phenyl ether, isobutoxymethyl(3-ethyl-3-oxetanylmethyl)ether, isobornyloxyethyl (3-ethyl-3-oxetanylmethyl) ether, isobornyl (3
-ethyl-3-oxetanylmethyl) ether, 2-ethylhexyl (3-ethyl-3-
oxetanylmethyl) ether, ethyl diethylene glycol (3-ethyl-3-oxetanylmethyl) ether, dicyclopentadiene (3-ethyl-3-oxetanylmethyl) ether, dicyclopentenyloxyethyl (3-ethyl-3-oxetanylmethyl) ether
ether, dicyclopentenyl (3-ethyl-3-oxetanylmethyl) ether, tetrahydrofurfuryl (3-ethyl-3-oxetanylmethyl) ether, tetrabromophenyl (3-ethyl-3-oxetanylmethyl) ether, 2-tetra Bromophenoxyethyl (3-ethyl-3-oxetanylmethyl) ether, tribromophenyl (3-ethyl-3-oxetanylmethyl) ether, 2-tribromophenoxyethyl (3-ethyl-3-oxetanylmethyl) ether, 2- Hydroxyethyl (3-ethyl-3-oxetanylmethyl) ether, 2-hydroxypropyl (3-ethyl-3-oxetanylmethyl) ether, butoxyethyl (3-ethyl-3-oxetanylmethyl) ether, pentachlorophenyl (3-ethyl) -3-oxetanylmethyl) ether, pentabromophenyl (3-ethyl-3-oxetanylmethyl) ether, bornyl (3-ethyl-3-
oxetanylmethyl)ether and the like, and compounds having two or more oxetane rings include 3,7-bis(3-oxetanyl)-5-oxa-nonane, 3,3′-(1,3-
(2-methylenyl)propanediylbis(oxymethylene))bis-(3-ethyloxetane), 1,4-bis[(3-ethyl-3-oxetanylmethoxy)methyl]benzene,
1,2-bis[(3-ethyl-3-oxetanylmethoxy)methyl]ethane, 1,3-bis[(3-ethyl-3-oxetanylmethoxy)methyl]propane, ethylene glycol bis(3-ethyl-3- oxetanylmethyl) ether, dicyclopentenyl bis(3-
ethyl-3-oxetanylmethyl) ether, triethylene glycol bis(3-ethyl-3-oxetanylmethyl) ether, tetraethylene glycol bis(3-ethyl-3
-oxetanylmethyl) ether, tricyclodecanediyldimethylene (3-ethyl-3
-oxetanylmethyl)ether, trimethylolpropane tris(3-ethyl-3-oxetanylmethyl)ether, 1,4-bis(3-ethyl-3-oxetanylmethoxy)ether
Butane, 1,6-bis(3-ethyl-3-oxetanylmethoxy)hexane, pentaerythritol tris(3-ethyl-3-oxetanylmethyl)ether, pentaerythritoltetrakis(3-ethyl-3-oxetanylmethyl)ether, polyethylene Glycol bis(3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol hexakis(3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol pentakis(3-ethyl-3-oxetanylmethyl) ether, dipenta Erythritol tetrakis (3-ethyl-3-oxetanylmethyl) ether, caprolactone-modified dipentaerythritol hexakis (3-ethyl-3-oxetanylmethyl) ether, caprolactone-modified dipentaerythritol pentakis (3-ethyl-3-oxetanylmethyl) ether Ether, ditrimethylolpropane tetrakis(3-ethyl-3-oxetanylmethyl)ether, EO-modified bisphenol A bis(3-ethyl-3-oxetanylmethyl)
Ether, PO modified bisphenol A bis (3-ethyl-3-oxetanylmethyl) ether, EO modified hydrogenated bisphenol A bis (3-ethyl-3-oxetanylmethyl) ether, PO modified hydrogenated bisphenol A bis (3-ethyl- 3-oxetanylmethyl)ether, EO-modified bisphenol F (3-ethyl-3-oxetanylmethyl)ether and the like. Among them, a compound having one oxetane ring is preferable because of the flexibility of the coating film.
Furthermore, from the viewpoint of adhesion to a substrate, a compound having one oxetane ring and one hydroxyl group is preferred.

(Other polymerizable compounds)
Polymerizable compounds other than the above (hereinafter referred to as "other polymerizable compounds") are not particularly limited, and other polymerizable compounds may be used as long as the effects of the present invention are not reduced.
Specific examples include compounds having polymerizable groups such as (meth)acryloyl groups, allyl groups, vinyl groups, vinyl ether groups, and internal double bond groups (eg, maleic acid) in the molecule. Among them, compounds having a vinyl group or a vinyl ether group are preferable from the viewpoint of cationic polymerization.

[Other ingredients]
In the present invention, the color ink composition includes an extender pigment, a resin, a leveling agent, an antistatic agent, a surfactant, a surface tension modifier, an antifoaming agent, a polymerization inhibitor, an ultraviolet Absorbents, antioxidants and the like can be added as required.

In addition, in the present invention, the color ink composition preferably does not substantially contain a basic compound. “Substantially free” means that the amount is preferably 1.0% by mass or less, more preferably 0.1% by mass or less, relative to the total mass of the color ink composition. By not including a basic compound in the color ink composition, the curability of the cationically polymerizable clear ink composition for the clear layer printed on the ink layer and the cationically polymerizable silicone composition for the release layer is improved. , the adhesion is also improved.

As used herein, the basic compound includes both organic basic compounds and inorganic basic compounds. The organic basic compound is a compound having higher basicity than phenol, and examples thereof include nitrogen-containing organic compounds and organic amines.

Specific examples of organic basic compounds include decylamine, dodecylamine, N,N-dimethyldodecylamine, stearylamine, cetylamine, benzylpiperidine, N,N-dimethylcyclohexylamine, mono-, di-, or triethanolamine, amino propanol, aminobutanol, aminohexanol, dimethylaminohexanol, morpholine, aminoethylmorpholine, aminopropylmorpholine, aminoethylpiperazine, aminoethylpyrrolidine, bis(hydroxyethyl)piperazine, aminopropylpyrrolidinone, aminoethoxyethanol, dimethylaminoethylmorpholine, Phenylmorpholine, 1,3-bis[1-(2-hydroxyethyl)-4-piperidyl]propane, Gramine, 1-(2-phenethyl)-4-piperidone, Ethylenediamine, Trimethylenediamine, Tetramethylenediamine, Hexamethylene diamine, aniline, N,N-diethylaniline, dodecylaniline, aminobiphenyl, aminophenol, 4-aminoacetanilide, aminoacetophenone, aminobenzamide, aminobenzanilide, aminobenzophenone, dimethylaminomethylthiophene, dimethylaminophenethyl alcohol,
Polyethyleneimines, polyarylamines, polyvinylpyridines, copolymers of N,N-dimethylaminoethyl methacrylate and methacrylates (eg butyl methacrylate), N,N-diethylaminoethyl methacrylate and acrylates (eg ethyl acrylate) a copolymer of dimethylaminomethylstyrene and styrene, 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol and 1,
Condensation polymer of 4-butanedioic acid, guanidine, 1,1-dimethylguanidine, 1,1,3
, 3,-tetramethylguanidine, 2-aminopyridine, 3-aminopyridine, 4-aminopyridine, 2-dimethylaminopyridine, 4-dimethylaminopyridine, 2-diethylaminopyridine, 2-(aminomethyl)pyridine, 2- amino-3-methylpyridine, 2
-amino-4-methylpyridine, 2-amino-5-methylpyridine, 2-amino-6-methylpyridine, 3-aminoethylpyridine, 4-aminoethylpyridine, 3-aminopyrrolidine, piperazine, N-(2- aminoethyl)piperazine, N-(2-aminoethyl)
piperidine, 4-amino-2,2,6,6-tetramethylpiperidine, 4-piperidinopiperidine, 2-iminopiperidine, 1-(2-aminoethyl)pyrrolidine, pyrazole,
3-amino-5-methylpyrazole, 5-amino-3-methyl-1-p-tolylpyrazole, pyrazine, 2-(aminomethyl)-5-methylpyrazine, pyrimidine, 2,4-diaminopyrimidine, 4,6 - dihydroxypyrimidines, 2-pyrazolines, 3-pyrazolines,
N-aminomorpholine, N-(2-aminoethyl)morpholine, 1,5-diazabicyclo[4.3.0]non-5-ene, 1,8-diazabicyclo[5.4.0]undeca-
7-ene, 1,4-diazabicyclo[2.2.2]octane, 2,4,5-triphenylimidazole, N-methylmorpholine, N-ethylmorpholine, N-hydroxyethylmorpholine, N-benzylmorpholine, cyclohexyl Morpholinoethylthiourea (CH
METU) and other tertiary morpholine derivatives.

In addition, 2-benzyl-2-(dimethylamino)-1 used as a radical polymerization initiator
-(4-morpholinophenyl)-1-butanone, 2-(dimethylamino)-2-[(4-
Methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone and the like are also included as organic basic compounds.

Examples of organic basic compounds include triethanolamine, p-dimethylaminobenzoic acid ethyl ester, p-formyldimethylaniline, p-methylthiodimethylaniline, and the like, which are used as radical polymerization accelerators.

Furthermore, a known polymer dispersant having a basic polar group and an amine value, which is used as a pigment dispersant, can also be mentioned as an organic basic compound. Specifically, Dis
perBYK®-161 (amine value 11 mg KOH/g), DisperBY
K-162 (amine value 13 mgKOH / g), DisperBYK-163 (amine value 1
0 mgKOH/g), DisperBYK-164 (amine value 18 mgKOH/g), D
isperBYK-166 (amine value 20mgKOH/g), DisperBYK-16
7 (amine value 13 mgKOH/g, oxide 0 mgKOH/g), DisperBYK-16
8 (amine value 10 mg KOH/g, oxide 0 mg KOH/g), Solsperse (registered trademark) 24000 manufactured by Lubrisol (amine value 47 mg KOH/g), Solsperse 320
00 (amine value: 27.1 mgKOH/g), Ajinomoto Fine Tech Co., Ltd. Ajisper (registered trademark) PB822 (amine value: 17 mgKOH/g), and the like.

[Physical properties of cationic polymerizable color ink composition for flexographic printing]
(viscosity)
In the present invention, the viscosity at 25° C. of the color ink composition is preferably 200
It is up to 1,000 mPa·s, more preferably 300 to 800 mPa·s. 25
When the viscosity at °C is within the above range, troubles such as poor transfer due to viscosity increase can be reduced in the process of transferring the ink composition in the order of the anilox roll, the plate, and the recording medium, and good flexographic printability can be achieved. can get. The viscosity was measured using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd.
It can be measured by reading the viscosity at 100 rpm in an environment of 25° C. using a VE-25 type viscometer, type E).

<Ink set for adhesive labels>
The ink set for adhesive labels in the present invention comprises the cationic polymerizable color ink composition for flexographic printing and the polymerizable clear ink composition. By using the ink set, migration components from the adhesive layer can be suppressed, and deterioration in adhesion between the substrate and the color ink layer over time can be suppressed.

<Polymerizable clear ink composition>
In this embodiment, either a cationically polymerizable clear ink composition or a radically polymerizable clear ink composition can be used. Components that are contained or can be contained in the polymerizable clear ink composition (hereinafter also referred to as clear ink) of the present embodiment are described below.

[Cationic polymerizable clear ink composition]
The cationic polymerizable clear ink composition contains a cationic polymerization initiator and a cationic polymerizable compound, and is characterized by substantially no colorant. “Substantially free” is preferably 1.0% by mass or less, more preferably 0.1% by mass or less, relative to the total mass of the clear ink composition.

As the cationic polymerization initiator, the cationic polymerization initiators exemplified as those included in the above-described color ink composition can be used. Among them, it is preferable to use an arylsulfonium salt derivative.

In the present invention, the content of the cationic polymerization initiator is the content of the cationic polymerization initiator contained in the color ink composition from the viewpoint of the curability of the film and the adhesion between the color ink layer and the clear ink layer. is preferably 0.5 to 30% by mass, 5 to 20
% by mass is more preferred.

As the cationically polymerizable compound, the cationically polymerizable compounds exemplified as those included in the above-described color ink composition can be used. Among them, 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate and 3-ethyl-3-hydroxymethyloxetane are preferably contained from the viewpoint of suppressing components migrating from the adhesive layer.

In the present invention, the cationically polymerizable clear ink composition contains a resin, a leveling agent, an antistatic agent, a surfactant, an antifoaming agent, a polymerization inhibitor, an ultraviolet absorber, and an antioxidant as long as the effects of the present invention are not reduced. Agents and the like can be added as necessary.

In the present invention, the cationically polymerizable clear ink composition may optionally contain other polymerizable compounds and other components exemplified as those included in the above-described color ink composition, as long as the effects of the present invention are not impaired. can be added as

In the present invention, the cationically polymerizable clear ink composition preferably does not substantially contain a basic compound, like the color ink composition described above. “Substantially free” is preferably 1.0% by mass or less, more preferably 0.1% by mass or less, relative to the total mass of the cationic polymerizable clear ink composition.

The basic compound is the same as the basic compound exemplified as one that is not substantially contained in the above-described color ink composition.

[Radical polymerizable clear ink composition]
The radically polymerizable clear ink composition is characterized in that it contains a radical polymerization initiator and a radically polymerizable compound, and does not substantially contain a colorant and a basic compound. “Substantially free” is preferably 1.0% by mass or less, more preferably 0.1% by mass or less, relative to the total mass of the clear ink composition.

The radical polymerization initiator is not particularly limited, and known photopolymerization initiators can be used. Specific examples include benzophenone compounds, dialkoxyacetophenone compounds, α-hydroxyalkylphenone compounds, acylphosphine oxide compounds, thioxanthone compounds and the like. Moreover, the said radical polymerization initiator may be used individually by 1 type, and may be used in combination of 2 or more type.

Examples of the benzophenone-based compounds include benzophenone, 4-methylbenzophenone,
4-phenylbenzophenone, [4-(methylphenylthio)phenyl]-phenylmethanone and the like.

Examples of the α-hydroxyalkylphenone compounds include 1-hydroxy-cyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-[4-(2-hydroxymethoxy)-phenyl ]-2-hydroxy-2-methyl-
1-propan-1-one, 2-hydroxy-1-[4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl]-2-methyl-propan-1-one and the like .

Examples of the above acylphosphine oxide compounds include diphenylacylphenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and the like. mentioned.

Examples of the thioxanthone compounds include 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, and 2,4-diethylthioxanthone.

The content of the radical polymerization initiator is preferably 1 to 25% by mass, more preferably 5 to 20% by mass, relative to the total mass of the radically polymerizable clear ink composition.

The radically polymerizable compound is not particularly limited, and known radically polymerizable compounds can be used. The polymerizable compound that can be used in the present invention is not particularly limited as long as it is a compound having one or more ethylenically unsaturated bonds in the molecule as a radically polymerizable group, and may be in the form of a monomer, an oligomer, or a polymer. also includes Further, the radically polymerizable compound may be used alone or in combination of two or more.

Examples of the radically polymerizable compound include 2-ethylhexyl (meth)acrylate, 2-
Hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, β-carboxylethyl (meth)acrylate, 4-tert-butylcyclohequinol (meth)acrylate, tetrahydrofurfuryl acrylate, alkoxylated tetrahydrofurfuryl acrylate, caprolactone (meth)acrylate, lauryl (meth)
acrylate, stearyl (meth)acrylate, isoamyl (meth)acrylate, 2
- phenoxyethyl (meth)acrylate, isodecyl (meth)acrylate, 3,3,
5-trimethylcyclohexanol (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, norbornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (oxyethyl) (meth)
Acrylates, 1,4-cyclohexanedimethanol (meth)acrylate, cyclic trimethylolpropane formal (meth)acrylate, benzyl (meth)acrylate, E
O-modified (2) nonylphenol acrylate, 2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl acrylate, monofunctional (meth)acryloyl group having one (meth)acryloyl group in the molecule such as acryloylmorpholine ) acrylate monomers,
N-vinylcarbazole, 1-vinylimidazole, N-vinyl-2-pyrrolidone, N-
monofunctional vinyl monomers having one vinyl group in the molecule such as vinylcaprolactam and N-vinylformamide;
1,3-butylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, 1
,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, 1,2-dodecanediol di(meth)acrylate, neopentyl glycol Di (meth) acrylate, polyethylene glycol (200) di (meth) acrylate, polyethylene glycol (300)
) di(meth)acrylate, polyethylene glycol (400) di(meth)acrylate, polyethylene glycol (600) di(meth)acrylate, neopentyl glycol hydroxypivalate di(meth)acrylate, dipropylene glycol di(meth)acrylate, Tripropylene glycol di(meth)acrylate, EO modified (2) 1,6-
Hexanediol di(meth)acrylate, PO-modified (2) neopentyl glycol di(
meth) acrylate, (neopentyl glycol-modified) trimethylolpropane di (meth) acrylate, dimethylol tricyclodecane di (meth) acrylate, EO-modified (4
) bisphenol A di (meth) acrylate, PO-modified (4) bisphenol A di (meth) acrylate, cyclohexanedimethanol di (meth) acrylate, dimethylol-
bifunctional (meth)acrylate monomers having two (meth)acryloyl groups in the molecule such as tricyclodecane di(meth)acrylate and dicyclopentanyl di(meth)acrylate;
Trimethylolpropane tri(meth)acrylate, EO-modified (3) Trimethylolpropane tri(meth)acrylate, PO-modified (3) Trimethylolpropane tri(meth)
Acrylates, ε-caprolactone-modified tris(2-acryloxyethyl)isocyanurate, ethoxylated isocyanuric acid tri(meth)acrylate, tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, pentaerythritol tri(meth)
A trifunctional (meth)acrylate monomer having three (meth)acryloyl groups in the molecule such as acrylate,
tetrafunctional (meth)acrylate monomers having four acryloyl groups in the molecule, such as pentaerythritol tetra(meth)acrylate and ditrimethylolpropane tetra(meth)acrylate;
Pentafunctional (meth)acrylate monomers having five (meth)acryloyl groups in the molecule such as dipentaerythritol penta(meth)acrylate,
A hexafunctional (meth)acrylate monomer having six (meth)acryloyl groups in the molecule, such as dipentaerythritol hexa(meth)acrylate, and the like.
In this specification, "(meth)acrylate" means either acrylate and/or methacrylate.

In the present invention, the above-mentioned radically polymerizable clear ink composition contains an extender, a resin, a leveling agent, an antistatic agent, a surfactant, an antifoaming agent, a polymerization inhibitor, and an ultraviolet absorbing agent, as long as the effects of the present invention are not reduced. Agents, antioxidants and the like can be added as required.

In the present invention, the radically polymerizable clear ink composition preferably does not substantially contain a basic compound, like the color ink composition described above. “Substantially free” is preferably 0.5% by mass or less, more preferably 0.1% by mass or less, relative to the total mass of the radically polymerizable clear ink composition.

[Physical properties of polymerizable clear ink composition]
(viscosity)
In the present invention, the viscosity of the polymerizable clear ink composition at 25° C. is 100 to 80
It is 0 mPa·s, more preferably 200 to 500 mPa·s. When the viscosity at 25°C is within the above range, troubles such as poor leveling can be reduced in the process of transferring the ink composition to the anilox roll, the plate, and the recording medium in that order, and good printed matter can be obtained. The viscosity was measured using an E-type viscometer (TVE-25 type viscometer manufactured by Toki Sangyo Co., Ltd., type
E) can be used to read the viscosity at 100 rpm in an environment of 25°C.

The ink set for adhesive labels in the present invention preferably further contains a release agent.

<Cationically polymerizable silicone composition>
In the present invention, the release agent is not particularly limited, and known release agents can be used. Among them, a cationically polymerizable silicone composition containing a cationic polymerization initiator and a polyorganosiloxane compound having an epoxy group is preferable from the viewpoint of productivity and release performance control.

Examples of the cationic polymerizable silicone composition include UVPOLY200, UVPOLY201, and UVPOLY215 of the silicone lease series manufactured by Arakawa Chemical Industries, Ltd.; 7655 and the like.

<Laminate for adhesive label>
In the adhesive label laminate of the present invention, the color ink composition is printed on one side of a base material having an adhesive layer on one side by a flexographic printing method, and then cured. After curing, the clear ink composition is printed thereon and cured, and the cationically polymerizable silicone composition as a release agent is printed and cured. As a result, it is possible to obtain a pressure-sensitive adhesive label laminate in which components migrating from the pressure-sensitive adhesive layer are suppressed, and deterioration in adhesion between the base material and the color ink layer over time is suppressed.

Thermal paper can be used as the recording medium. in particular,
GS80, HE90, GG50 manufactured by Oji Paper Co., Ltd.; 150LA-1, 150LHB manufactured by Ricoh Co., Ltd.;

In the present invention, the method for curing the color ink composition, the clear ink composition, and the cationically polymerizable silicone composition is not particularly limited, and known methods can be used. For example, it can be cured by irradiation with α-rays, γ-rays, electron beams, X-rays, ultraviolet rays, visible light, infrared light, or the like. Among them, ultraviolet rays and electron beams are preferable, and ultraviolet rays are more preferable. The peak wavelength of ultraviolet rays is preferably 200-600 nm, more preferably 250-420 nm.

The ultraviolet light source is not particularly limited, and any known ultraviolet light source can be used. in particular,
Mercury lamp, xenon lamp, metal hydride lamp, ultraviolet light emitting diode (UV
-LED), ultraviolet laser diode (UV-LD) and other LEDs (light-emitting diodes), and gas/solid-state lasers.

The color ink composition and the clear ink composition are preferably printed so that the film thickness of the coating film is 1 to 20 μm, more preferably 5 μm to 10 μm.

EXAMPLES Examples and comparative examples are shown below to describe the present invention more specifically. However, the present invention is not limited to these. In the examples and comparative examples, "parts" and "%" represent "mass parts" and "mass%", respectively.

[Preparation of cationic polymerizable color ink composition for flexographic printing]
color ink 1
Five parts of JER1001 as the cationically polymerizable compound (A) and 10 parts of CER4221 as the cationically polymerizable compound (B) were mixed, and JER1001 was heated and dissolved while stirring. Then, 35 parts of CER4221 and PIGMENT YE as a coloring agent.
15 parts of LLOW 1453T was added and dispersed with a triple roll so that the maximum particle size was 20 μm or less. Then, 15 parts of AT-6992 were added and stirred to prepare a cationic polymerizable color ink composition.

Cationic polymerizable color inks 2 to 24
Inks 2 to 24 were obtained in the same manner as for Ink 1, except that the raw materials and amounts were changed as shown in Table 1.

[Preparation of radically polymerizable color ink composition for flexographic printing]
ink 24
15 parts of Viscoat 230D as a radical polymerization compound and LION as a colorant
15 parts of OL YELLOW TT1842 and Ajisper PB822 as a pigment dispersant
and 5 parts of Omnirad 369 as a radical polymerization initiator, and Omnirad
Add 7 parts of TPO and disperse with 3 rolls so that the maximum particle size is 20 μm or less, then add 25 parts of MIRAMER M3130 and 20 parts of MIRAMER M600 and stir to obtain a radically polymerizable color. An ink composition was prepared.

Radically polymerizable color inks 24 to 26
Inks 24 to 26 were obtained in the same manner as for ink 24, except that the raw materials and amounts were changed as shown in Table 1.

なお、空欄は配合していないことを表す。

In addition, the blank represents that it is not compounded.

[Preparation of cationic polymerizable clear ink composition]
Clear 1
As cationic polymerizable compounds, 10 parts of jER1001 and 5 parts of celoxide 2021P
0 part and 20 parts of OXT-101 were added, and jER1001 was heated and dissolved while stirring. After that, as a cationic polymerization initiator, 5 parts of AT-6992, as other resins, FLEX
10 parts of OREZ-188 and 5 parts of Fine Oxocol 180 as a surface tension modifier were added and stirred to prepare a cationic polymerizable clear ink composition.

[Preparation of Radical Polymerizable Clear Ink Composition]
clear 2
As a radically polymerizable compound, 30 parts of MIRAMER M600, Sartomer SR3
30 parts of 06 and 25 parts of Photomer 4028 were added followed by 5 parts of Omnirad 4MBZ.
part, 5 parts of Omnirad 481, fine oxocol 180 as a surface tension modifier
was added, and the mixture was heated and stirred to prepare a radically polymerizable clear ink composition.

Clear 3
Clear 3 was obtained in the same manner as Clear 2, except that the raw materials and amounts listed in Table 2 were changed.

Abbreviations in Tables 1 and 2 are as follows.
[Coloring agent]
Pigment Yellow 1453T: Sanyo Pigment Co., Ltd., C.I. I. Pigm
ent Yellow 14

[Cationic polymerization initiator]
・AT-6992: manufactured by ACETO

[Cationically polymerizable compound]
・ JER828: manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy compound, Mw3
70, epoxy equivalent 120
・ JER834: manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy compound, Mw4
70, epoxy equivalent 230
・ JER1001: manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy compound, Mw
900, epoxy equivalent 450
・ JER1002: manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy compound, Mw
1200, epoxy equivalent 875
・ JER1004: manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy compound, Mw
1650, epoxy equivalent 875
・ JER1007: manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy compound, Mw
2900, epoxy equivalent 1750
・TTA15: Sun Chemical Co., Ltd., 3,4-epoxycyclohexylmethyl methacrylate ・CER4221: Achiewell Co., Ltd., 3,4-epoxycyclohexylmethyl-
(3,4-epoxy) cyclohexane carboxylate TTA26: manufactured by Sun Chemical Co., Ltd., bis (3,4-epoxycyclohexylmethyl) adipate Epolite 1600: manufactured by Kyoeisha Co., Ltd., 1,6-hexanediol diglycidyl ether OXT -101: manufactured by Toagosei Co., Ltd., 3-ethyl-3-hydroxymethyloxetane OXT-212: manufactured by Toagosei Co., Ltd., 2-ethylhexyloxetane OXT-121: manufactured by Toagosei Co., Ltd., xylene bisoxetane OXT- 221: manufactured by Toagosei Co., Ltd., 3-ethyl-3 {[(3-ethyloxetane-
3-yl)methoxy]methyl}oxetane

[Radical polymerization initiator]
・Omnirad369: manufactured by iGM RESINS, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1
・OmniradTPO: iGM RESINS, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide ・Omnirad4MBZ: iGM RESINS, 4-methylbenzophenone ・Darocure 1173: BASF, 2-hydroxy-2-methyl-1 -phenyl-1
-Propanone/Omnirad 481: iGM RESINS, 1-hydroxycyclohexylphenyl ketone

[Radical polymerizable compound]
・Viscoat 230D: 1,6-hexanediol acrylic acid ester multimeric ester manufactured by Osaka Organic Chemical Industry Co., Ltd. ・Miramer M3130: Miwon Specialty Chemical
Co. , Ltd., EO-modified (3) trimethylolpropane triacrylate Miramer M600: Miwon Specialty Chemical C
o. , Ltd., dipentaerythritol hexaacrylate photomer 4028: iGM RESINS, EO-modified bisphenol A diacrylate Sartomer SR306: Sartomer, tripropylene glycol diacrylate Ebecryl 8415: Allnex, urethane acrylate

[Basic compound]
Ajisper PB822: manufactured by Ajinomoto Phi Chemicals Co., Ltd., basic pigment dispersant, amine value 17 mgKOH/g

[resin]
・Beamset 271: Amine-modified acrylate polymer manufactured by Arakawa Chemical Co., Ltd. ・FLEXOREZ-188: Polyester polyol manufactured by Kusumoto Kasei Co., Ltd.

[Surface tension modifier]
・Fine Oxocol 180: Isooctadecanol manufactured by Nissan Chemical Co., Ltd.

[Method for preparing test samples]
Test sample 1
The resulting color ink composition was applied to thermal paper (150LA manufactured by Ricoh Co., Ltd.) as a base material using an anilox roller having a line number of 800 LPI and a cell volume of 3.72 cm ³ /m ² and a flexiproof machine. was printed, and cured with a conveyor speed of 50 m/min and an air-cooled mercury lamp (output of 160 w/cm ² ). After that, after printing the obtained clear ink 1 on the color ink layer using an anilox roller with a line number of 400 LPI and a cell volume of 9.48 cm ³ /m ² , an air-cooled mercury lamp lamp ( It was cured under conditions of an output of 160 w/cm ² ). Furthermore, on the clear layer, the number of lines is 400 LPI,
After printing silicone release UVPOLY215 (manufactured by Arakawa Chemical Co., Ltd.) as a release agent using an anilox roller with a cell volume of 9.48 cm ³ /m ² , a conveyor speed of 50 m/min and an air-cooled mercury lamp (output of 160 w/cm ² conditions). hardened with Then, a test sample 1 was obtained in which the substrate, the color ink layer, the clear ink layer, and the release layer were laminated in this order.

Test samples 2-26
Test samples 2 to 26 were obtained in the same manner as sample 1, except that the color ink and clear ink shown in Table 3 were changed.

[Curability of release agent]
The release layer surfaces of test samples 1 to 29 prepared by the above method immediately after curing were touched with a finger and evaluated according to the following criteria. A score of 3 or more is evaluated as a practically acceptable level.
5: Completely no stickiness.
4: Almost no stickiness.
3: Almost no stickiness, but slightly sticky.
2: Slightly sticky.
1: There is stickiness.

[Adhesion to substrate immediately after curing]
Test samples 1 to 29 prepared by the above method were subjected to a cellophane tape peeling test between the print layer surface and the substrate, and evaluated according to the following criteria. A score of 3 or more is evaluated as a practically acceptable level.
5: No peeling at all.
4: About 5% of the adhesive surface is peeled off.
3: About 15% of the adhesive surface is peeled off.
2: 50% or more of the adhesive surface is peeled off.
1: Peel off entirely.

[Peelability over time]
The print layer surface of test samples 1 to 29 prepared by the above method and the adhesive layer surface of thermal paper coated with an adhesive (Sabinol manufactured by Saiden Chemical Co., Ltd.) are superimposed, and a load of 10 kg per square centimeter is applied, It was allowed to stand at 60°C for 10 days. 10 days later, 25°C
The printed surface and the adhesive layer surface were peeled off with , and the state of the printed surface was visually evaluated according to the following criteria. A score of 3 or more is evaluated as a practically acceptable level.
5: Good releasability without affecting the printed surface.
4: The printed surface is not affected, but peeling resistance is slightly felt.
3: There is no effect on the printed surface, but peeling resistance is felt.
2: The printed surface adheres to the adhesive surface, and the printed surface peels off in an area of less than 50%.
1: The printed surface and the adhesive surface adhered, and the printed surface peeled off over an area of 50% or more.

[Flexibility]
Test samples 1 to 29 obtained by the above method are folded back 180° so that the release layer is on the inside, and further folded 180° so that the release layer is on the outside. , was visually evaluated according to the following criteria. A score of 3 or more is evaluated as a practically acceptable level.
5: No influence on the printed surface and no cracking of the film.
4: The printed surface is not affected, but slight cracks are observed.
3: The printed surface is not affected, but some cracking of the film is observed.
2: The printed surface is slightly cracked, and the base material can be confirmed.
1: The printed surface is cracked, and the base material can be confirmed.

Claims (6)

A cationic polymerizable color ink composition for flexographic printing comprising a colorant, a cationic polymerization initiator, and a cationic polymerizable compound,
The cationically polymerizable compound contains an epoxy compound (A) having a bisphenol A structure, an alicyclic epoxy compound (B) (except when it becomes (A)), and an oxetane compound (C),
The content of the epoxy compound (A) is 5 to 20% by mass with respect to the total mass of the color ink composition,
The content of the alicyclic epoxy compound (B) is 10 to 50% by mass with respect to the total mass of the color ink composition,
The content of the oxetane compound (C) is 10 to 30% by mass with respect to the total mass of the color ink composition,
The epoxy compound (A) has a weight average molecular weight of 400 to 2,000,
A cationic polymerizable color ink composition for flexographic printing, characterized by being substantially free of basic compounds. The cationic polymerizable color ink composition for flexographic printing according to claim 1 , wherein the alicyclic epoxy compound (B) has an epoxy equivalent of 110 to 250. 3. The cationic polymerizable color ink composition for flexographic printing according to claim 1 , wherein the oxetane compound (C) has one oxetane ring and one hydroxyl group in its structure. A polymerizable ink set for adhesive labels, comprising the cationic polymerizable color ink composition for flexographic printing according to any one of claims 1 to 3 and a polymerizable clear ink composition. Furthermore, as a release agent, it has a cationically polymerizable silicone composition,
5. The polymerizable ink set for adhesive labels according to claim 4 , wherein the cationic polymerizable silicone composition contains a cationic polymerization initiator and a polyorganosiloxane compound having an epoxy group. A polymerizable ink set for adhesive labels according to claim 5 is applied to the surface opposite to the adhesive layer of a base material having an adhesive layer on one side thereof, a cationic polymerizable color ink composition for flexographic printing, and a polymerizable clear ink composition. , and a cationically polymerizable silicone composition.