JP2011063652A - Photosensitive ink and cured product using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide cation-polymerizable photosensitive ink which has satisfactory curability, releases little benzene upon light irradiation, and enables a cured product excellent in adhesion and solvent resistance to be formed. <P>SOLUTION: The cation-polymerizable photosensitive ink includes a polymerizable compound which can be polymerized by an acid, a photoacid generator containing a benzene ring, and a sensitizer. The weight of the photoacid generator is 0.5-10% of the weight of the polymerizable compound, and the content (m<SB>1</SB>mol) of the photoacid generator and the content (m<SB>2</SB>mol) of the sensitizer satisfy a relationship of the expression: 1<(m<SB>2</SB>/m<SB>1</SB>)≤5. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a photosensitive ink and a cured product using the same.

  Until now, in many commercial printing markets, printing has been performed using solvent-type ink in which a coloring material is dispersed in a volatile organic solvent. In recent years, solvent-free inks are being used in consideration of the influence on the global environment. The use of water-based inks is also under consideration, but the productivity of water-based inks that require time for drying in commercial printing is reduced. There is also a problem with the water resistance of the printed matter.

  For this reason, photosensitive ink has attracted attention as a solventless ink. Photosensitive inks can be printed directly on non-absorbing media. After printing, the printing can be fixed instantaneously by light irradiation without releasing the solvent, and the evaporation of the organic solvent is small. As a polymerization initiator in a photosensitive ink, a radical generator has been widely used so far. The radical polymerization type ink containing the radical generator has a low sensitivity to light because the polymerization is inhibited by oxygen in the atmosphere, and the adhesion to the substrate is not sufficient.

  On the other hand, a cationic polymerization type ink using a photoacid generator as a polymerization initiator is a chemically amplified photosensitive ink. The acid generated by the light irradiation is diffused by heating, so that the polymerization reaction can be efficiently caused to the inside of the ink. High sensitivity without oxygen inhibition and excellent adhesion to the substrate.

  In the cationic polymerization type UV ink, a photoacid generator containing a benzene ring is usually used as a polymerization initiator. When the cured film obtained by light irradiation is heated, benzene is released from the polymerization initiator and released. In order to suppress the generation of benzene from the coating film during the heat treatment, it has been proposed to replace the hydrogen atom of the benzene ring in the polymerization initiator with an alkyl chain (see, for example, Patent Document 1).

  The present invention provides a cationic polymerization type photosensitive ink that has sufficient curability and has little benzene emission by light irradiation and can form a cured product having excellent adhesion and solvent resistance, and a cured product using the same. The purpose is to do.

The cationic polymerization type photosensitive ink according to one aspect of the present invention includes a polymerizable compound that can be polymerized with an acid,
A cationic polymerization type photosensitive ink containing a photoacid generator containing a benzene ring and a sensitizer,
The weight of the photoacid generator is 0.5% or more and 10% or less of the weight of the polymerizable compound,
The content of the photoacid generator (m ₁ mol) and the content of the sensitizer (m ₂ mol) satisfy the following relationship.

1 <(m ₂ / m ₁ ) ≦ 5
The cured product according to one embodiment of the present invention is obtained using the above-described photosensitive ink.

  According to the present invention, a cationic polymerization type photosensitive ink that has sufficient curability and has little benzene emission by light irradiation and can form a cured product having excellent adhesion and solvent resistance, and a cured product using the same. Is provided.

  Embodiments of the present invention will be described below.

  In a coating film obtained by cationically curing a UV ink containing a photoacid generator containing a benzene ring, benzene is released from the photoacid generator during UV irradiation and remains in the coating film. When heating is subsequently performed, benzene in the coating film is released from the coating film. When a cured product formed using a cationic curing type UV ink is subjected to heat treatment, for example, in a solder reflow process of a printed circuit board, benzene is generated. If attention is paid to ventilation etc., it can be suppressed to a level where there is no problem in environmental measurement, but if it is processed in large quantities in a sealed state, a detectable amount may be generated, so measures against such benzene emissions are necessary. It is.

In cationic curable UV inks, sulfonium salts and iodonium salts are widely used as photoacid generators. In particular, it is a compound represented by the following chemical formulas (1), (2), (3), and contains a benzene ring. In any case, no substituent is bonded to the benzene ring. Since it is an unsubstituted benzene ring, bonds with adjacent atoms are easily broken during light irradiation, and benzene is generated as a by-product.

  Compared to the case of such an unsubstituted benzene ring, the generation of benzene is less in a benzene ring having an alkyl group introduced as a substituent. Even in that case, the present inventors confirmed that benzene was produced to a degree that could be sufficiently detected and quantified. In the case where a vinyl ether compound is used as the polymerizable compound, the generation of benzene is particularly remarkable. In curing the UV ink, the illuminance of the ultraviolet rays is set to be very high so that the printing speed can be avoided and the curing can be performed in a short time. For this reason, it is estimated that a by-product is also likely to be generated.

  In this embodiment, even if it uses the above conventional photo-acid generators, it aims at suppressing generation | occurrence | production of benzene. The photoacid generator used is a photoacid generator containing a benzene ring that generates benzene by light irradiation. That is, at least one benzene ring among the benzene rings is not bonded to a substituent. Or it has a C1-C20 linear alkyl group or a C3-C20 branched alkyl group as a substituent. More preferably, light containing an unsubstituted benzene ring, a benzene ring introduced with a linear alkyl group having 1 to 14 carbon atoms, or a benzene ring introduced with a branched alkyl group having 3 to 5 carbon atoms is used. It is an acid generator. Such a benzene ring is easily broken by a photoreaction to generate benzene. However, it is often used because of its excellent manufacturing cost, solubility, and absorption wavelength.

Examples of the photoacid generator include onium salts in which an iodonium cation, a sulfonium cation, or a phosphonium cation forms a counter ion with an anion. As the iodonium cation, for example, a diaryl iodonium salt represented by the following general formula (4) can be used.

(In the general formula (4), R ¹ and R ² may be the same or different and are a hydrogen atom or a substituent having 1 to 20 carbon atoms, at least one of which is hydrogen or having 1 to 20 carbon atoms. A straight-chain alkyl group or a branched alkyl group having 3 to 20 carbon atoms, more preferably a straight-chain alkyl group having 1 to 14 carbon atoms or a branched alkyl group having 3 to 5 carbon atoms.)
Examples of anions include fluoroborate anion, hexafluoroantimonate anion, hexafluoroarsenate anion, trifluoromethanesulfonate anion, paratoluenesulfonate anion, paranitrotoluenesulfonate anion, halogen anion, sulfonate anion, carboxylic acid anion, Alternatively, a sulfate anion can be used as a counter ion.

  Further, for example, photoacids such as diazonium salts, quinonediazide compounds, organic halides, aromatic sulfonate compounds, bisulfone compounds, sulfonyl compounds, sulfonate compounds, sulfonium compounds, sulfamide compounds, iodonium compounds, sulfonyldiazomethane compounds, and mixtures thereof Generating agents can be used.

As a more detailed specific example of an onium salt, the compound represented by the following chemical formula is mentioned, for example.

  Examples of commercially available onium salt compounds include the following. Midori Chemical Co., Ltd. MPI-103 (CAS.NO. [87709-41-9]), Midori Chemical Co., Ltd. BDS-105 (CAS.NO. [145612-66-4]), Midori Chemical Co., Ltd. No. [20032-64-8]), DTS-102 (CAS.NO. [75482-18-7]) manufactured by Midori Chemical Co., Ltd., and DTS-103 (CAS. NO. [71449-78- manufactured by Midori Chemical Co., Ltd.). 0]), MDS-103 (CAS.NO. [127279-74-7]) manufactured by Midori Chemical Co., Ltd., MDS-105 (CAS.NO. [116808-67-4]) manufactured by Midori Chemical Co., Ltd., manufactured by Midori Chemical Co., Ltd. MDS-205 (CAS.NO. [81416-37-7]), BMS-105 (CAS.NO. [14993] manufactured by Midori Chemical Co., Ltd.) 4-68-9]), TMS-105 (CAS.NO. [127820-38-6]) manufactured by Midori Chemical Co., Ltd., NB-101 (CAS.NO. [20444-09-1] manufactured by Midori Chemical Co., Ltd.), NB-201 (CAS.NO. [4450-68-4]) manufactured by Midori Chemical Co., Ltd., DNB-101 (CAS.NO. [114719-51-6] manufactured by Midori Chemical Co., Ltd.), DNB-102 (manufactured by Midori Chemical Co., Ltd.) CAS.NO. [131509-55-2]), Midori Chemical Co., Ltd. DNB-103 (CAS.NO. [132898-35-2]), Midori Chemical Co., Ltd. DNB-104 (CAS.NO. [132898-36] -3]), DNB-105 (CAS.NO. [132898-37-4]) manufactured by Midori Chemical Co., Ltd., DAM-101 (CAS.NO. [1886-74-4] manufactured by Midori Chemical Co., Ltd.) DAM-102 (CAS.NO. [28343-24-0]) manufactured by Midori Chemical Co., Ltd. DAM-103 (CAS.NO. [14159-45-6] manufactured by Midori Chemical Co., Ltd.), DAM-104 manufactured by Midori Chemical Co., Ltd. (CAS.NO. [130290-80-1], CAS.NO. [130290-82-3]), Midori Chemical DAM-201 (CAS.NO. [2832-50-1]), and Lamberti ESACURE 1064 manufactured by Lamberti, CPI-100P manufactured by San Apro (CAS. No. [68156-13-8]), WPI-054 manufactured by Wako Pure Chemical Industries (CAS. No. [524678-29-3]), WPI-113 manufactured by Wako Pure Chemical Industries (CAS. No. [477602-76-9]), WPI manufactured by Wako Pure Chemical Industries, Ltd. 116 (CAS. No. [71786-70-4]), WPI-170 (CAS No. [61358-25-6]) manufactured by Wako Pure Chemical Industries, IRGACURE250 manufactured by Ciba-Geigy Corporation, and the like.

  Among the onium salts described above, sulfonium salts and iodonium salts are excellent in stability. However, due to the production process, in general, in addition to a monovalent salt (a salt of a monovalent cation and a single anion), a salt having a bivalent or higher valence (for example, a divalent cation and about 75%) is used. A salt with two anions) is inevitably included. In general, commercially available products are also in the state of such a mixture, and this tendency is particularly noticeable with sulfonium salts. It is known that when a polyvalent salt is contained in a photosensitive ink, the photosensitive wavelength shifts to the long wavelength side, and generally the sensitivity becomes high. In order to ensure such advantages, a divalent or higher salt may be intentionally mixed. For example, commercially available products such as Lamberti ESACURE-1064 and the like correspond to them.

  The polyvalent salt greatly affects the aggregation stability of the powder contained in the photosensitive ink. Specifically, the polyvalent salt also has a drawback in that a weak bond is generated between the powder particles and the dispersant to cause generation of a gel or an aggregate. For this reason, when the photosensitive ink contains a powder, usually, suppressing the presence of these polyvalent salts as much as possible leads to an improvement in the dispersion stability of the powder particles.

  The content of the polyvalent onium salt is desirably 20 parts by weight or less of the total amount of the onium salt. The content of the polyvalent onium salt is more preferably 5 parts by weight or less, and most preferably it is not contained.

  Among the onium salt compounds described above, an arylsulfonium fluorophosphate salt or an aryliodonium fluorophosphate salt is preferable because of its excellent powder aggregation stability. Even if it is a monovalent onium salt, when the dispersant is insufficient, it has an action of gradually replacing the terminal amine resin as the dispersant with time. For this reason, it is desirable that the onium salt has a structure in which it is difficult to approach the bonding portion between the powder surface and the end of the dispersant as much as possible. This is possible by using an onium salt compound having a relatively large substituent in the structure. If the benzene ring in the onium salt has an organic group having 1 to 20 carbon atoms, ion adsorption on the powder surface is reduced by steric hindrance. This effect is more remarkable when 50 mol% or more of the benzene rings have an organic group having 4 to 20 carbon atoms. In addition to dispersion stability, safety of the product is enhanced because scattering of decomposed products into the air during photoreaction is suppressed. In addition, since such a compound has high solubility in a solvent, a phenomenon such as salt precipitation in the photosensitive ink can be suppressed.

  When a monovalent onium salt is used, the photosensitive wavelength shifts to the short wavelength side, so that the sensitivity tends to decrease. Such an inconvenience can be avoided if the structure contains an aromatic substituent having sulfur or oxygen as VI elements in the heterocyclic ring or as a linking group.

Furthermore, as shown in the following general formula (5) or (6), in the case of an onium salt containing a relatively large organic group in the structure, the dissolution stability is high and the dispersion stability is also good.

Here, A ⁻ is a fluorophosphate anion, R ¹ , R ² , and R ³ are a hydrogen atom or a substituent having 1 to 20 carbon atoms, and R ⁴ is a divalent aromatic substituent or VI A divalent aromatic substituent containing an atom in the structure is shown. At least one of R ¹ , R ² , and R ³ is a hydrogen atom, a linear alkyl group having 1 to 20 carbon atoms, or a branched alkyl group having 3 to 20 carbon atoms, and more preferably one having 1 to carbon atoms. 14 linear alkyl groups or branched alkyl groups having 3 to 5 carbon atoms.

Examples of the organic group having 1 to 20 carbon atoms that can be introduced as R ¹ to R ³ include a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decanyl group. An alkyloxy group having 1 to 20 carbon atoms such as an alkyl group, a methyloxy group, an ethyloxy group, a propyloxy group, a butyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a nonyloxy group, and a decanyloxy group; Examples thereof include a substituent having 3 to 20 carbon atoms having a polyethylene oxide skeleton dehydrated and condensed. At least one of R ¹ to R ³ has a linear alkyl group having 1 to 14 carbon atoms or a branched alkyl group having 3 to 5 carbon atoms.

Examples of the divalent aromatic substituent that can be introduced as R ⁴ include groups having phenylene such as phenylene and biphenylene; groups having a phenylene sulfide skeleton such as phenylene sulfide and phenylene disulfide; benzothiophenylene and thiophenylene. And groups having a thiophene skeleton such as a bithiophenylene group; groups having a furan skeleton such as furanylene and benzofuranylene.

  The content of the photoacid generator can be set according to the acid generation efficiency, the amount of the powder component to be added, and the like. In the embodiment of the present invention, the photoacid generator is contained in an amount of 0.5% to 10% of the weight of the polymerizable compound from the viewpoint of sensitivity. When the content of the photoacid generator is less than 0.5% by weight, the sensitivity of the photosensitive ink is lowered. On the other hand, if it exceeds 10% by weight, the ink deteriorates with time and the viscosity increases with time, and the coating properties and the hardness of the ink film after photocuring decrease. Preferably, the content of the photoacid generator is 1% by weight to 8% by weight with respect to 100% by weight of the polymerizable compound, and can be appropriately determined according to the acid generation efficiency, the amount of pigment to be added, and the like. . The amount of benzene generated is less as the content of the photoacid generator is smaller. Therefore, it is desirable that the amount of photoacid generator is as small as possible in the above optimal range.

  The optimum content varies depending on the type of photoacid generator used. For example, in the case of ESACURE1187, 1% by weight to 7% by weight of the polymerizable compound is preferable, and 3% by weight to 5% by weight is more preferable.

  The polymerizable compound is a compound (cationically polymerizable compound) that crosslinks or polymerizes in the presence of an acid generated by light irradiation under a photoacid generator and a sensitizer. For example, compounds having a molecular weight of 1000 or less having cyclic ether groups such as epoxy groups, oxetane groups, oxolane groups, acrylic or vinyl compounds having the above substituents in the side chain, carbonate compounds, low molecular weight melamine compounds, vinyl ethers Polymerizable compounds with cationically polymerizable vinyl bonds such as vinyl alcohols, vinyl carbazoles, styrene derivatives, alpha-methyl styrene derivatives, vinyl alcohol esters such as vinyl alcohol and acrylic, methacrylic ester compounds, etc. May be.

  Acrylic compounds having a terpenoid skeleton in the ester side chain can also be used. For example, acrylic compounds as disclosed in JP-A-08-82925 are suitable. Specifically, terpene having an unsaturated bond such as myrcene, carene, osymene, pinene, limonene, camphene, terpinolene, tricyclene, terpinene, fenchen, ferrandlene, sylvestrene, sabinene, dipentene, bornene, isopulegol, carvone, etc. Examples include ester compounds in which a double bond is epoxidized and acrylic acid or methacrylic acid is added.

  Or citronellol, pinocamphetol, geraniol, fentil alcohol, nerol, borneol, linalool, menthol, terpineol, twill alcohol, citronellal, yonon, iron, cinerol, citral, pinole, cyclocitral, carbomenton, ascaridol, safranal Terpene-derived alcohols and acrylics such as piperitol, menthene monool, dihydrocarbon, carveol, sclareol, manol, hinokiol, ferguinol, totarol, sugiol, farnesol, patchouliol, nerolidol, carotol, casinomol, lanseol, eudesmol, phytol An ester compound with acid or methacrylic acid may be used.

  In addition, citronellolic acid, hinokic acid, santalic acid, menthone on the side chain, carbotanaseton, ferrandral, pimelitenone, perillaldehyde, tsuyon, caron, daggerton, camphor, bisabolene, santalen, gingiveren, caryophyllene, curcumen, cedrene, kazinene, Longifolene, sesquibenien, cedrol, guayol, kesoglycol, cyperone, elemophyllone, zerumbone, camphorene, podocarprene, mylene, phyllocladene, totalene, ketomanoyl oxide, manoyl oxide, abietic acid, pimaric acid, neoabietic acid, levopimaric acid, -D-pimaric acid, agatendicarboxylic acid, rubenic acid, carotenoid, perarialdehyde, piperitone, ascaridol, pimene, fenken, Containing an acrylate or methacrylate compound having a skeleton such as a skiterpene, diterpene, or triterpene in the ester side chain, an acrylic or methacrylate monomer, a styrene monomer, or an oligomer compound having a plurality of vinyl polymerizable groups. Is desirable.

  Moreover, the polyacrylate compound of a polyhydric alcohol compound, the polyacrylate compound of a polyvalent aromatic alcohol, the polyacrylate compound of a polyhydric alicyclic alcohol, the styrene-type compound which has a substituent, etc. are mentioned. Examples of such monomers include ethylene glycol, polyethylene glycol, propylene glycol, glycerin, neopentyl alcohol, trimethylolpropane, pentaerythritol, di-polyacrylate compounds such as vinyl alcohol oligomers, phenol, cresol, naphthol, Bisphenol, their novolak condensation compounds and diphenol-polyacrylate compounds of vinylphenol oligomers, etc., and hydrogenated cyclohexane, hydrogenated bisphenol, decahydronaphthalene alicycle, terpene alicyclic, dicyclo Examples thereof include di-polyacrylate compounds of di-polyhydroxy compounds of pentane and tricyclodecane alicyclic rings.

  Of these, oxirane compounds, oxetane compounds, and vinyl ether compounds are preferably used.

  As the oxirane compound, any compound usually used as an epoxy resin can be used. Specific examples include monomers, oligomers, and polymers such as aromatic epoxides, alicyclic epoxides, and aliphatic epoxides.

  More specifically, for example, celiacide 2021, Celoxide 2021A, Celoxide 2021P, Celoxide 2081, Celoxide 2000, and Celoxide 3000, manufactured by Daicel Chemical Industries, are (meth) acrylate compounds having epoxy groups and epoxy groups. Cyclomer A200, Cyclomer M100, methacrylate having methyl glycidyl group such as MGMA, glycidol which is a low molecular weight epoxy compound, β-methylepicholorhydrin, α-pinene oxide, C12-C14 α-olefin monoepoxide, C16-C18 α-olefin monoepoxide, epoxidized soybean oil such as Daimac S-300K, epoxidized linseed oil such as Daimac L-500, Epolide GT301, Epolide Or the like can be mentioned a multifunctional epoxy, such as the T401. In addition, US Dow Chemical's alicyclic epoxy such as Cyracure, hydrogenated and aliphatic low molecular weight phenolic compounds with hydroxyl groups substituted with epoxy groups, ethylene glycol, glycerin, neopentyl alcohol Glycidyl ether compounds such as polyhydric aliphatic alcohols / alicyclic alcohols such as hexanediol and trimethylolpropane, hexahydrophthalic acid, glycidyl esters of hydrogenated aromatic polycarboxylic acids, and the like can be used.

  In particular, an epoxy compound having an alicyclic skeleton can be used suitably in the case of ink jet printing because it can achieve both a certain high boiling point and low viscosity in addition to reactivity.

  Moreover, as a thing with not high mutagenicity by an AMES test, the thing with a comparatively small molecular weight is preferable, and alicyclic epoxy compounds, such as Celoxide 3000, are used suitably. The molecular weight is preferably 150 or more and 300 or less. If it is less than 150, the mutagenicity becomes high. On the other hand, if it exceeds 300, the storage stability tends to deteriorate.

  The content of the oxirane compound is desirably 30% by weight or less in the polymerizable compound. More preferably, it is 3 to 20% by weight. When the oxirane compound is contained within such a range, the adhesion and solvent resistance of the formed cured product are further enhanced.

  As the oxetane compound, for example, a compound having two oxetane rings and a compound having one oxetane ring can be used. Examples of the compound having two oxetane rings include di [1-ethyl (3-oxetanyl)] methyl ether, 1,4-bis [(1-ethyl-3-oxetanyl) methoxy] benzene, 1,3-bis. [(1-ethyl-3-oxetanyl) methoxy] benzene, 4,4′-bis [(3-ethyl-3-oxetanyl) methoxy] biphenyl, 1,4-bis {[(3-ethyl-3-oxetanyl) Methoxy] methyl} benzene, bis [(1-ethyl-3-oxetanyl) methoxy] cyclohexane, bis [(1-ethyl-3-oxetanyl) methoxy] norbornane, and the like. Examples of the compound having one oxetane ring include 3-ethyl-3- (phenoxymethyl) oxetane, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane, 3-ethyl-3-hydroxymethyloxetane, [(1-ethyl-3-oxetanyl) methoxy] cyclohexane, oxetanylsilsesquioxane and the like. An acrylic compound having an oxetane group in the side chain, a methacryl compound having an oxetane group in the side chain, and the like can also be used. When such a compound is contained, an increase in viscosity can be suppressed, and in addition, a curing acceleration effect similar to that of the oxetane compound can be obtained.

  In order to improve adhesion to various metals such as SUS, copper and aluminum, plastic materials such as PET (polyethylene terephthalate), PP (polypropylene), PC (polycarbonate), and various materials such as glass, 3 -Ethyl-3- (phenoxymethyl) oxetane is preferably used.

  Moreover, by using a bifunctional oxetane compound, it becomes a photosensitive ink in which the solvent resistance of the cured product is further improved. Oxetane compounds may be used alone or in combination of two or more.

  When 30% by weight or less of the oxirane compound is contained in the total amount of the polymerizable compound, the content of the oxetane compound is preferably 20 to 60% by weight of the total amount of the polymerizable compound.

  By using the photosensitive ink in which the oxirane compound and the oxetane compound are contained in the polymerizable compound at such a ratio, it is possible to form a cured product without further deteriorating the adhesion and further improving the film strength.

  Vinyl ether compounds have a particularly fast curing rate and a high reaction rate among polymerizable compounds. In order to improve the curing performance of the photosensitive ink, it is desired that at least one vinyl ether compound is contained in the polymerizable compound.

  However, it has been confirmed by the present inventors that the amount of benzene remaining in the coating film after the light irradiation is remarkably increased in the photosensitive ink containing the vinyl ether compound. It is presumed that this is because the polymer of the vinyl ether compound tends to adsorb benzene. The rate of the polymerization reaction of the vinyl ether compound is faster than other polymerizable compounds. For this reason, it is speculated that the generated benzene is confined in the cured film and easily remains.

  In photosensitive inks in which vinyl ether compounds are used as the polymerizable compound, the generation of benzene is maintained while maintaining high curing performance by defining the molar ratio of the sensitizer and the photoacid generator within a predetermined range. Can be suppressed. That is, when the vinyl ether compound is used, the effect of the embodiment of the present invention is particularly remarkable.

As the vinyl ether compound, a compound represented by the following general formula (7) is used.

(In the general formula (7), R ¹¹ is selected from the group consisting of a vinyl ether group, a group having a vinyl ether skeleton, an alkoxy group, a hydroxyl group-substituted product, and a hydroxyl group, and at least one has a vinyl ether group or a vinyl ether skeleton. ¹² is a p + 1 valent group having a substituted or unsubstituted cyclic skeleton or aliphatic skeleton, and p is a positive integer including 0.)
p is 0, when the cyclohexane ring skeleton is introduced as R ^12, from the viewpoint of volatility, it is more preferable that the R ¹² contained oxygen. Specifically, at least one carbon atom contained in the ring skeleton is preferably a structure having a ketone structure, a structure substituted with an oxygen atom, or a structure having an oxygen-containing substituent.

  In general, vinyl ether compounds bonded to methylene groups such as aliphatic glycol derivatives and cyclohexanedimethanol are well known. Such a polymerization reaction of the vinyl ether compound is significantly inhibited by the powder. In addition, since the viscosity is relatively high, it has been difficult to prepare a photosensitive ink containing such a vinyl ether compound and powder. In the vinyl ether compound represented by the general formula (7), at least one vinyl ether group is directly bonded to an alicyclic skeleton, a cyclic ether compound, a terpenoid skeleton, or an aromatic skeleton. For this reason, even if it contains with powder, it is excellent in hardening performance.

In the general formula (7), examples of the (p + 1) -valent organic group R ¹² include a (p + 1) -valent group including a benzene ring, a naphthalene ring, and a biphenyl ring, a cycloalkane skeleton, a norbornane skeleton, an adamantane skeleton, And (p + 1) -valent groups derived from bridged alicyclic compounds such as a cyclodencan skeleton, a tetracyclododecane skeleton, a terpenoid skeleton, and a cholesterol skeleton.

  More specifically, cyclohexane (poly) ol, norbornane (poly) ol, tricyclodecane (poly) ol, adamantane (poly) ol, benzene (poly) ol, naphthalene (poly) ol, anthracene (poly) ol, Examples thereof include alicyclic polyols such as biphenyl (poly) ol, and compounds in which a hydrogen atom of a hydroxyl group in a phenol derivative is substituted with a vinyl group. Moreover, the compound etc. which substituted the hydrogen atom of the hydroxyl group in polyphenol compounds, such as polyvinyl phenol and a phenol novolak, by the vinyl group can also be used. In the compound as described above, a part of the hydroxyl group may remain. Alternatively, there is no problem even if some of the methylene atoms of the alicyclic skeleton are oxidized or substituted with ketone groups, lactones, oxygen atoms, or the like. In such a case, volatility is reduced, which is desirable.

  In particular, cyclohexyl monovinyl ether compounds are highly volatile. For this reason, when a cyclohexyl monovinyl ether compound is used, it is desirable that the cyclohexane ring is oxidized to at least a cyclohexanone ring or the like.

  Among such compounds, a cyclic ether compound having a substituent containing a vinyl ether structure is more preferable. In terms of curability and safety, a cyclic ether skeleton containing a five-membered ring skeleton containing an oxygen atom and simultaneously having a bridged structure and a spiro structure is most suitable. Such a vinyl ether compound is obtained by replacing the alcohol with vinyl ether using a corresponding alcohol compound and a vinyl ether source such as vinyl acetate or propenyl ether as starting materials, for example, using a catalyst such as iridium chloride (J. Am. Chem.Soc.Vol124, No8, 1590-1591 (2002)).

  Among the above-described compounds, epoxy compounds, oxetane compounds, and vinyl ether compounds having a naturally occurring skeleton such as a terpenoid skeleton and a norbornane skeleton are favorable in terms of cost.

Examples of such cyclic ether compounds include, for example, compounds represented by the following chemical formula.

  As vinyl ether compounds having no ring structure, specifically, vinyl ether compounds having a poly (alkylene glycol) skeleton having relatively low volatility are generally well known. As such a vinyl ether compound, for example, triethylene glycol divinyl ether is often used at low cost. When a vinyl ether compound having no ring structure is blended, the adhesion of the coating film to the base material is greatly lowered. In addition, the ultimate hardness tends to decrease. For this reason, the vinyl ether compound preferably has a ring structure.

The cyclic compound having a substituent containing a vinyl ether structure described above is preferably 30% by weight or more as the content in the polymerizable compound. If it is 30% by weight or more, the hardness and solvent resistance of the cured coating film will be sufficiently high.
The vinyl ether compounds may be used alone or in combination of two or more.

  It is desirable that at least one polymerizable compound of the oxetane compound and the specific vinyl ether compound is a monofunctional compound. By containing a monofunctional compound, the shrinkage of the obtained cured product can be controlled. That is, by appropriately adding a monofunctional compound, shrinkage that occurs during the curing process of the acid polymerizable compound is suppressed, and as a result, the adhesion of the cured product is enhanced. The content of the monofunctional compound is defined as 20 to 70% by weight of the total polymerizable compound. If the monofunctional compound is contained in such an amount, a cured product having high adhesion to the substrate and sufficient hardness can be formed. The content of the monofunctional compound is preferably 30 to 50% by weight.

  For example, a photosensitive ink blended in a formulation of 20 to 40% by weight of a monofunctional oxetane compound, 10 to 30% by weight of a bifunctional oxetane compound, 3 to 20% by weight of an oxirane compound, and 30 to 50% by weight of a vinyl ether compound is cured. The strength of the product is increased, and this is particularly preferable in terms of solvent resistance.

  In the case of containing a bifunctional oxetane compound, the degree of crosslinking of the cured film is increased, so that the solvent resistance is greatly enhanced. When the content of the bifunctional oxetane compound is 18% by weight or more and the content of the monofunctional oxetane compound is 30% by weight or less, if the heating condition after light irradiation is 120 ° C. or less, the light It does not adhere immediately after heating after irradiation. Adhesion develops when left for several days.

  Any polymerizable compound as described above can be used as long as it has fluidity at room temperature. Specifically, a viscosity range of 0.1 Pa · s to 500 Pa · s is used for screen printing and the like, and a viscosity of 1 mPa · s to 50 mPa · s is used for inkjet printing and the like. The viscosity of the polymerizable compound can be measured, for example, with a cone plate viscometer.

  Examples of the sensitizer include acridine compounds, benzoflavins, perylenes, anthracenes, thioxanthone compounds, and laser dyes. Of these, compounds in which some hydrogen atoms of dihydroxyanthracene are substituted with organic groups, thioxanthone derivatives, and the like are highly effective.

For example, an anthracene diether compound represented by the following general formula (8) is used.

  In the general formula (8), R is a monovalent organic group, and examples thereof include an alkyl group, an aryl group, a benzyl group, a hydroxyalkyl group, an alkoxyalkyl group, and a vinyl group.

  Specific examples of the alkyl group include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, t-butyl group, n-pentyl group, and i-pentyl group. Etc. Examples of the aryl group include a phenyl group, a biphenyl group, an o-tolyl group, an m-tolyl group, and a p-tolyl group. Examples of the hydroxyalkyl group include a 2-hydroxyethyl group and a 3-hydroxypropyl group. Group, 2-methyl-2-hydroxyethyl group, 2-ethyl-2-hydroxyethyl group and the like. Examples of the alkoxyalkyl group include a 2-methoxyethyl group, a 3-methoxypropyl group, a 2-ethoxyethyl group, and a 3-ethoxypropyl group. Furthermore, an allyl group, a 2-methylallyl group, a vinyl group, or the like may be introduced. Such a compound can be synthesized by a method as shown in, for example, (J. Am. Chem. Soc., Vol. 124, No. 8 (2002) 1590).

  The RO group in the general formula (8) is preferably a group that polymerizes with an acid. Examples of such RO groups include vinyl ether groups, propenyl ether groups, epoxy groups, oxetane groups, and oxolane groups. A sensitizer is also involved in the polymerization reaction with a photoacid generator, and a polymerization reaction is generated. Will be incorporated into things. Further, when the RO group is a group that dissociates by acid or heat to generate an OH group, it is similarly involved in the polymerization reaction by the photoacid generator and incorporated into the polymerization reaction product. Examples of such RO groups include tert-butyl group, tert-butoxycarbonyl group, acetal group, and silicone-containing group.

  That is, when the R group itself in the general formula (8) is polymerized, the sensitizer becomes a part of the polymerization product. Alternatively, when an OH group generated by acid or heat in the sensitizer is bonded to the polymerizable compound, the sensitizer becomes part of the polymerization product. By this, it is possible to further advance the degree of polymerization of the polymerization reaction, it is possible to improve the final curing performance (hardness), by using the photosensitive ink according to the embodiment of the present invention, The durability of the resulting cured product can also be improved.

In the general formula (8), R ¹⁴ and R ¹⁵ may be the same or different and each represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an alkylsulfonyl group, or an alkoxy group. Any group may be used as long as these groups are used, but considering the ease of synthesis, R ¹⁴ and R ¹⁵ may be any hydrogen atom.

  Examples of the compound represented by the general formula (8) include 9,10-dimethoxyanthracene, 9,10-diethoxyanthracene, 9,10-dipropoxyanthracene, 9,10-dibutoxyanthracene, and 2-ethyl-9. Dialkoxyanthracene such as 1,10-diethoxyanthracene (2,3-diethyl-9,10-diethoxyanthracene), 9,10-diphenoxyanthracene, 9,10-diallyloxyanthracene, 9,10- Examples include di (2-methylallyloxy) anthracene, 9,10-divinyloxyanthracene, 9,10-di (2-hydroxyethoxy) anthracene, and 9,10-di (2-methoxyethoxy) anthracene. Any of these compounds exerts a sufficient effect, but in consideration of the cost of obtaining the compound or its synthesis raw material and the safety of the compound, 9,10-dibutoxyanthracene, 9,10-diethoxyanthracene 9,10-dipropoxyanthracene and 9,10-divinyloxyanthracene are particularly preferred.

In the ink according to the embodiment of the present invention, the sensitizer is contained in a predetermined amount with respect to the photoacid generator. Specifically, when the number of moles of the photoacid generator is m ₁ and the number of moles of the sensitizer is m ₂ , the following relationship is necessary.

1 <(m ₂ / m ₁ ) ≦ 5
When utilizing the sensitizing action of the sensitizer, the sensitizer is usually blended in a smaller number of moles than the photoacid generator. The sensitizer is excited by absorbing the irradiation light, and a sensitizing action is generated by transferring the energy to the photoacid generator. If the number of moles of photoacid generator is less than the sensitizer, there will be insufficient photoacid generator molecules to receive energy from the excited sensitizer. A portion that is not used for the sensitizing action is generated and is wasted, and the sensitivity of the photosensitive ink is lowered. Since it is used for the purpose of sensitization, the number of moles of the sensitizer has heretofore been set to the same amount as that of the photoacid generator.

  The present inventors have found that the sensitizer has an action as a benzene generation inhibitor. The generation mechanism of benzene is considered as follows. When the photoacid generator containing a benzene ring is subjected to excessive UV irradiation, the photoacid generator is excessively decomposed by a photoreaction. Benzene is produced as a by-product by breaking the bond to the part that should not be cut. In order to suppress this, it is necessary to reduce the light absorbed by the photoacid generator.

  It is effective to increase light absorption by the sensitizer and reduce light absorption by the photoacid generator. At this time, the light absorbed by the sensitizer is transferred to the photoacid generator as much as the photoacid generator is present, and contributes to the polymerization reaction.

  The light absorbed by the sensitizer in a larger amount than the photoacid generator does not contribute to the sensitization effect, but is effective in reducing the side reaction of benzene generation. In order to reduce light absorption by the photoacid generator, it is necessary that the number of moles of the sensitizer is larger than the number of moles of the photoacid generator. The absorption of light by the sensitizer absorbs not only the light absorption wavelength used in the reaction for generating the acid by the photoacid generator, but also the shorter wavelength (high wavelength) because it absorbs light of a shorter wavelength. It is possible to suppress an unexpected decomposition reaction by absorbing light of energy.

  For example, when a metal halide lamp is used as the light irradiation light source, light having a distribution in a wide wavelength range is irradiated even when a lamp having a main wavelength of 365 nm is used. Therefore, a lot of light having a wavelength of about 254 nm is also irradiated. When, for example, ESACURE 1064 is used as the photoacid generator, the acid generation reaction usually proceeds by light around 365 nm. Light with a short wavelength of about 254 nm does not contribute to this acid generation reaction. When the illuminance of the irradiation light is strong like a metal halide lamp, it is estimated that a side reaction of a small amount of benzene is generated. Since the sensitizer described above absorbs light of such a short wavelength, the light absorption of the photoacid generator can be reduced and benzene generation can be suppressed.

In order to prevent the photoacid generator from absorbing light, the amount of the sensitizer should be large. However, as described above, if the sensitizer is excessive, the light absorbed by the sensitizer is wasted. The number of moles of the sensitizer that can sufficiently suppress the generation of benzene without extremely deteriorating the curing reaction needs to be 5 times or less the number of moles of the photoacid generator. If it exceeds this, sufficient cured performance of the cured film cannot be obtained, and solvent resistance, hardness, and the like are lowered. Further, when the number of moles of the sensitizer was 1 time or less than the number of moles of the photoacid generator, the generation of benzene was not sufficiently reduced, and the generation amount was more than allowable. The ratio (m ₂ / m ₁ ) between the number of moles of photoacid generator m ₁ and the number of moles of sensitizer m ₂ is preferably 1.5 or more and 2.5 or less.

  The photosensitive ink according to the embodiment of the present invention may contain powder for imparting various functions.

  The powder is not particularly limited as long as it can be dispersed in the above-described photosensitive ink dispersion medium and adds a function to the photosensitive ink. Mainly, magnetic, fluorescent, conductive, insulating, dielectric, or electromagnetic heat generating powders can be mentioned. Moreover, powder etc. which can improve heat resistance and mechanical strength can be used. Specifically, metal or metal oxide, metal nitride, metal carbide, metal carbonate, metal sulfide, inorganic and organic phosphors, carbon fiber, and the like are used.

  As the powder for imparting electrical conductivity, metal is mainly used. Examples thereof include gold, silver, copper, platinum, palladium, nickel, indium, titanium, antimony, tin, rhodium, ruthenium, and alloys of these metals. These metal oxides may be used, and an ITO film or the like can be produced, or a metal film can be produced by performing a reduction treatment after coating or exposure. In addition to metal, conductive carbon powder or carbon fiber can also be used.

As the powder exhibiting fluorescence, either an inorganic phosphor or an organic phosphor may be used. Examples of the inorganic phosphor material include MgWO ₄ , CaWO ₄ , (Ca, Zn) (PO ₄ ) ₂ : Ti ⁺ , Ba ₂ P ₂ O ₇ : Ti, BaSi ₂ O ₅ : Pb ²⁺ , Sr _2. Examples include inorganic acid salts such as P ₂ O ₇ : Sn ²⁺ , SrFB ₂ O _3.5 : Eu ²⁺ , MgAl ₁₆ O ₂₇ : Eu ²⁺ , tungstate and sulfurate. Examples of organic phosphor materials include acridine orange, aminoacridine, quinacrine, anilinonaphthalenesulfonic acid derivatives, anthroyloxystearic acid, auramine O, chlorotetracycline, merocyanine, 1,1′-dihexyl-2, Cyanine dyes such as 2'-oxacarbocyanine, dansylsulfoamide, dansylcholine, dansylgalacside, dansyltrizine, dansyl chloride derivatives such as dansyl chloride, diphenylhexatriene, eosin, ε-adenosine, ethidium bromide, fluorescein Fomycin, 4-benzoylamide-4′-aminostilbene-2,2′-sulfonic acid, β-naphthyl triphosphate, oxonol dye, parinaric acid derivative, perylene, N-phenylnaphthy Amine, pyrene, safranine O, fluorescamine, fluorescein isocyanate, 7-chloronitrobenzo-2-oxa-1,3-diasol, dansylaziridine, 5- (iodoacetamidoethyl) aminonaphthalene-1-sulfonic acid, 5- Iodoacetamidofluorescein, N- (1-anilinonaphthyl4) maleimide, N- (7-dimethyl-4-methylcoumanyl) maleimide, N- (3-pyrene) maleimide, eosin-5-iodoacetamide, fluorescein mercury acetate, 2 -(4 '-(2''-iodoacetamido)) aminonaphthalene-6-sulfonic acid, eosin, rhodamine derivative, organic EL dye, organic EL polymer, crystal, dendrimer and the like can be mentioned.

  As the powder that can improve the insulation, for example, an insulating ceramic powder, a crystallized glass powder, and other insulating powders contained in a green sheet can be used.

  Examples of the powder capable of improving heat resistance and physical strength include fillers such as aluminum or silicon oxide or nitride, silicon carbide, talc, and mica. Further, iron oxide and ferromagnetic powder are suitable for imparting magnetism, and metal oxide powder such as tantalum and titanium having a high dielectric constant can also be blended.

  The above-mentioned powders can be used alone or in admixture of two or more.

  The content of the powder component is not particularly limited, but for example, in the case of imparting conductivity, the content is preferably large, and is preferably 20% by weight or more and 98% by weight or less.

  As the pigment or powder, any pigment having a desired optical coloring and coloring function can be used. When an inkjet ink is used, the average particle diameter of the pigment or powder is defined to be 300 nm or less. If the average particle size is 300 nm or more, many ejection defects will occur when ejecting from the inkjet head. The average particle diameter of the pigment or powder is preferably 200 nm or less, more preferably 180 nm or less.

  The particle diameter of the pigment or powder can be determined, for example, by the following method. First, the ink sample is diluted to about 500 times in a solvent, the particle size is measured by a dynamic light scattering method for the diluted sample, and the cumulant average particle size is calculated by cumulant analysis. The value thus obtained is taken as the average particle diameter of the pigment. In addition, as a value of an average particle diameter, z value (intensity average) by a dynamic light scattering method can be used. Such a measurement can be performed using, for example, a Zetasizer manufactured by Malvern.

  Examples of usable pigments include light-absorbing pigments. Specifically, carbon-based pigments such as carbon black, carbon refined, and carbon nanotubes, metal oxide pigments such as iron black, cobalt blue, zinc oxide, titanium oxide, chromium oxide, and iron oxide, zinc sulfide Sulfide pigments such as, phthalocyanine pigments, pigments consisting of salts such as metal sulfates, carbonates, silicates, and phosphates, and metal powders such as aluminum powder, bronze powder, and zinc powder The pigment which consists of these is mentioned.

  Further, for example, dye chelate, nitro pigment, aniline black, nitroso pigments such as naphthol green B, azo pigments such as Bordeaux 10B, Lake Red 4R, and chromoftal red (azo lakes, insoluble azo pigments, condensed azo pigments, chelate azos) ), Rake pigments such as peacock blue lake and rhodamine lake, phthalocyanine pigments such as phthalocyanine blue, polycyclic pigments (perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxane pigments, thioindigo pigments, Organic pigments such as isoindolinone pigments, quinofuranone pigments), selenium pigments such as thioindigo red and indatron blue, quinacridone pigments, quinacridine pigments, and isoindolinone pigments. It is also possible to use.

  Examples of pigments that can be used in black ink include Raven 5750, Raven 5250, Raven 5000, Raven 3500, Raven 1255, Raven 700, manufactured by Columbia, Regal 400R, Regal 330R, Regal 660R, Mogul L, manufactured by Cabot. Monarch 700, Monarch 800, Monarch 880, Monarch 900, Monarch 1000, Monarch 1100, Monarch 1300, Monarch 1400, No. 1 manufactured by Mitsubishi Chemical Corporation. 2300, no. 900, MCF88, No. 33, no. 40, no. 45, no. 52, MA7, MA8, MA100, No2200B, Degussa Color Black FW1, Color Black FW2, Color Black FW2V, Color Black FW18, Color Black FW200, Color Black S150, Color Black S150, Color Black S150, Color Black FW200, Color Black FW200, Color Black FW200, Color Black FW200 Carbon blacks such as U, Printex V, Printex 140U, Special Black 6, Special Black 5, Special Black 4A, and Special Black 4 may be mentioned.

  Examples of pigments that can be used in yellow ink include C.I. I. Pigment Yellow 128, C.I. I. Pigment Yellow 129, C.I. I. Pigment Yellow 151, C.I. I. Pigment Yellow 154, C.I. I. Pigment Yellow 1, C.I. I. Pigment Yellow 2, C.I. I. Pigment Yellow 3, C.I. I. Pigment Yellow 12, C.I. I. Pigment Yellow 13, C.I. I. Pigment Yellow 14C, C.I. I. Pigment Yellow 16, C.I. I. Pigment Yellow 17, C.I. I. Pigment Yellow 73, C.I. I. Pigment Yellow 74, C.I. I. Pigment Yellow 75, C.I. I. Pigment Yellow 83, C.I. I. Pigment Yellow 93, C.I. I. Pigment Yellow 95, C.I. I. Pigment Yellow 97, C.I. I. Pigment Yellow 98, C.I. I. Pigment Yellow 114, C.I. I. Pigment Yellow 139, C.I. I. Pigment Yellow 150, Pigment Yellow 180, and the like. Among these yellow pigments, Pigment Yellow 180, which causes little color deterioration with respect to acid, is desirable.

  Examples of pigments that can be used in magenta ink include C.I. I. Pigment Red 123, C.I. I. Pigment Red 168, C.I. I. Pigment Red 184, C.I. I. Pigment Red 202, C.I. I. Pigment Red 5, C.I. I. Pigment Red 7, C.I. I. Pigment Red 12, C.I. I. Pigment Red 48 (Ca), C.I. I. Pigment Red 48 (Mn), C.I. I. Pigment Red 57 (Ca), C.I. I. Pigment Red 57: 1, C.I. I. Pigment Violet 19 and C.I. I. Pigment Red 112 and the like.

  Further, examples of pigments that can be used in cyan ink include C.I. I. Pigment Blue 15: 3, C.I. I. Pigment Blue 15:34, C.I. I. Pigment Blue 16, C.I. I. Pigment Blue 22, C.I. I. Pigment Blue 60, C.I. I. Pigment Blue 1, C.I. I. Pigment Blue 2, C.I. I. Pigment Blue 3, C.I. I. Vat Blue 4, and C.I. I. Vat Blue 60 etc. are mentioned.

  Also useful are white pigments such as natural clay, lead white, zinc white and metal carbonates such as magnesium carbonate, and metal oxides such as barium and titanium. The ink-jet ink containing a white pigment can be used not only for white printing but also for printing correction and overlaid correction by overwriting.

  The pigment is desirably contained in a ratio of 1% by weight to 50% by weight with respect to 100% by weight of the ink. If it is less than 1% by weight, it is difficult to ensure a sufficient color density. On the other hand, if it exceeds 50% by weight, the ink ejection performance is lowered. More preferably, the content of the pigment other than white is in the range of 2 to 8% by weight, and the content of the white pigment is in the range of 5 to 30% by weight.

Depending on the type of pigment or the like, the curability of the ink may decrease. It is desirable to determine the ratio (m ₂ / m ₁ ) between the number of moles of photoacid generator m ₁ and the number of moles of sensitizer m _{2 in} order to ensure appropriate curing performance.

  When a pigment or powder is contained, a photosensitive ink according to an embodiment of the present invention can be prepared by blending predetermined components in a solvent and performing a dispersion treatment with a disperser. Of the components described above, the polymerizable compound acts as a solvent in the photosensitive ink according to the embodiment of the present invention. As a disperser, a commonly used one can be used. Specifically, examples of the disperser include a sand mill, a ball mill, a roll mill, and an ultrasonic disperser, but are not limited thereto. In addition, a medialess disperser can also be used.

  In the dispersion treatment, the effect is enhanced by adding a dispersant. As the dispersant, for example, a dispersant such as a nonionic or ionic surfactant or a charging agent, or a polymer dispersant such as acrylic or vinyl alcohol can be used. The addition amount can be appropriately determined according to the type of pigment, solvent, etc., but is usually about 20 to 70% by weight with respect to the pigment.

  When used for inkjet recording, the viscosity of the photosensitive ink according to the embodiment of the present invention thus prepared is regulated to 50 mPa · sec or less at room temperature (25 ° C.). When the viscosity exceeds 50 mPa · sec, it becomes difficult to eject from the ink jet recording head.

When printing is performed using the photosensitive ink according to the embodiment of the present invention, the printing method is not particularly limited, such as inkjet printing, screen printing, flexographic printing, gravure printing, offset printing, spin coating, and slit coating. After printing, light irradiation is performed using an arbitrary light source. A light source capable of irradiating ultraviolet rays is not particularly limited, such as a high-pressure mercury lamp, a metal halide lamp, and an ultraviolet LED, but a metal halide lamp having a large irradiation illuminance is most desirable in consideration of the printing speed. Usually 150~300mJ / cm ² as the accumulated light quantity, but it is preferable that its photosensitive in about 1500~3000mW / cm ² at peak irradiance, but is not limited differs to the formulation of the ink.

  The amount of benzene remaining in the coating film can be measured by the following method. For example, a coating film having a film thickness of 5 to 8 μm is formed on a substrate, and 1 mg is scraped and accommodated in a glass sample tube for ATD. Using this as a sample, benzene is measured by the ATD-GC / MS (solid adsorption-heat desorption-gas chromatograph mass spectrometry) method. Desorption from the sample is performed at 250 ° C. By using such an analysis method, it is possible to quantitatively detect benzene remaining in the coating film. It is considered that the amount of benzene generated is substantially allowed when the detected amount per 1 mg of the coating film is 50 ng or less. The photosensitive ink according to the embodiment of the present invention satisfies this condition.

  The amount of benzene released during UV irradiation is measured as follows. A known weight of photosensitive ink is applied to the substrate and sealed in a glass container. In this state, the ink is cured by light irradiation in the same manner as described above. Then, the gas in a glass container is sampled and the amount of benzene is analyzed by GC / MS.

  As described above, the photosensitive ink and its cured product according to the embodiment of the present invention have sufficient curability, adhesion, and solvent resistance, and release benzene by light irradiation and benzene residue on the coating film. It becomes possible to suppress.

Hereinafter, the present invention will be described in more detail with reference to specific examples.
The following five types of compounds were prepared as polymerizable compounds.

Celoxide 3000: Limonene dioxide (Daicel Chemical)
OXT221: 3-ethyl-3 {[(3-ethyloxetane-3-yl) methoxy] methyl} oxetane (Toagosei)
OXT211: 3-ethyl-3- (phenoxymethyl) oxetane (Toagosei)
ONB-DVE: Hydroxymethyl-hydroxyoxanorbornanediol divinyl ether (Daicel Chemical)
TDVE: Triethylene glycol divinyl ether (ISP Japan)
Using these, main ingredients (Nos. 1 to 5) of photosensitive ink were prepared according to the formulation shown in Table 1 below.

Using the obtained main agent, photosensitive inks of Examples and Comparative Examples were prepared with a predetermined composition. The amount of the photoacid generator, the ratio (m ₂ / m ₁ ) of the number of moles of photoacid generator (m ₁ ) to the number of moles of sensitizer (m ₂ ), and the amount of pigment are Table 2 and Table 3 below together with the types. The pigment used was titanium oxide, and the blending amount of the pigment and the photoacid generator was% by weight based on the main agent.

  Each component in the table is the following compound.

Photoacid generator ESA 1064: ESACURE 1064 (LAMBERTI)
ESA1187: ESACURE1187 (LAMBERTI)
WPI-113 (Wako Pure Chemical Industries)
ESA1064 and ESA1187 are sulfonium salts, and WPI-113 is an iodonium salt, which are compounds represented by the following chemical formulae.

Sensitizer DBA: 9,10-dibutoxyanthracene (Kawasaki Chemical)
DPA: 9,10-dipropoxyanthracene (Kawasaki Chemical)
DEA: 9,10-diethoxyanthracene (Kawasaki Chemical)
A coating film was formed on the substrate using each ink. Specifically, each of the photosensitive inks was coated on a stainless steel substrate using a bar coater to form a coating film having a thickness of about 8 μm. The obtained coating film was irradiated with UV light with a peak light intensity of 1800 mW / cm ² and an integrated light amount of 250 mJ / cm ² using a metal halide lamp (Light Hammer 6, manufactured by Fusion), and then heated at 150 ° C. for 15 minutes. Thus, a cured film was obtained.

  About the obtained cured film, hardening hardness, solvent resistance, and adhesiveness were investigated and hardening performance was evaluated.

  In evaluating the solvent resistance, the surface of the cured product was rubbed with a cotton swab impregnated with ethanol, and the number of times until the cured product was peeled off was examined. The cured hardness was evaluated based on a pencil hardness test (JIS K5600-5-4, ISO / DIS 15184). A pencil hardness of 3H or higher was accepted (◯), and a pencil hardness of less than (X).

The results obtained are summarized in Tables 4 and 5 below.

  In addition, adhesiveness was evaluated based on the cross-cut peeling test (JIS K5600-5-6, ISO 2409). It was confirmed that all the cured films of Examples and Comparative Examples had no problem in adhesion.

  Furthermore, the amount of benzene remaining in the cured film was measured. A sample was prepared by scraping 1 mg of the cured coating film and accommodated in a glass sample tube. This was heated at 250 ° C. for 2 minutes to desorb benzene from the sample, and then collected in a secondary trap. Benzene was quantitatively measured by the ATD-GC / MS (solid adsorption-thermal desorption-gas chromatograph mass spectrometry) method to determine the residual amount (ng) per 1 mg of the coating film. The measured value is the residual amount in the coating film. The benzene remaining in the coating film is released by heating.

In addition, the amount of benzene released during UV irradiation was measured. In the same manner as described above, an ink having a known weight was applied to a stainless steel substrate by a bar coater. About each board | substrate, the light was irradiated like the above in the state sealed to the glass container, and the ink was hardened. Then, the gas in a glass container was sampled and the amount of benzene was analyzed by GC / MS, and the amount of benzene released (ng) per 1 mg of the coating film was determined. The measured value is the amount emitted during light emission.

  The present inventors have confirmed that there is no problem if the amount of benzene remaining in the coating film is 50 ng or less per 1 mg of the coating film. Similarly, the amount of benzene released from the coating during light irradiation is acceptable as long as it is 50 ng or less per 1 mg of coating.

As shown in the above table, in the photosensitive inks of the examples, the amount of benzene is suppressed within an allowable range. In addition, it has sufficient curing performance (solvent resistance, hardness). In the inks of these examples, the molar ratio (m ₂ / m ₁ ) between the sensitizer and the photoacid generator is specified to be greater than 1 and 5 or less, so that the reduced amount of benzene and excellent curing are achieved. We were able to balance performance.

The ink of the comparative example cannot achieve both a reduced benzene amount and excellent curing performance. In the inks of Comparative Examples 1 and 3 to 5, the amount of benzene remaining per 1 mg of the coating film exceeds 50 ng. In these inks, the molar ratio (m ₂ / m ₁ ) between the sensitizer and the photoacid generator is specified to be 1 or less. On the other hand, the ink of Comparative Example 2 having a molar ratio (m ₂ / m ₁ ) greater than 5 cannot ensure solvent resistance and hardness.

JP 2002-241474 A

Claims (11)

A polymerizable compound polymerizable by an acid,
A cationic polymerization type photosensitive ink containing a photoacid generator containing a benzene ring and a sensitizer,
The weight of the photoacid generator is 0.5% or more and 10% or less of the weight of the polymerizable compound,
The content of the photoacid generator content of the (m ₁ mol) and the sensitizer and (m ₂ moles), the cationic polymerization type photosensitive inks and satisfying the following relationship.
1 <(m ₂ / m ₁ ) ≦ 5   The photosensitive ink according to claim 1, wherein the photoacid generator is an onium salt.   The photosensitive ink according to claim 2, wherein the onium salt is selected from the group consisting of a diaryliodonium salt and a triarylsulfonium salt. The photosensitive ink according to claim 2, wherein the onium salt is a compound represented by the following chemical formula (9).

  The photosensitive ink according to claim 4, wherein the compound represented by the chemical formula (1) is contained in an amount of 1% to 7% of the weight of the polymerizable compound.   The benzene ring has no substituent, or is bonded with a substituent selected from at least one of a linear alkyl group having 1 to 20 carbon atoms and a branched alkyl group having 3 to 20 carbon atoms. The photosensitive ink according to claim 1, wherein the photosensitive ink is a photosensitive ink.   The photosensitive ink according to claim 1, wherein the polymerizable compound contains at least one vinyl ether compound.   The photosensitive ink according to claim 1, wherein the sensitizer is an anthracene compound.   The photosensitive ink according to claim 1, further comprising a powder.   The photosensitive ink according to claim 1, further comprising a pigment or powder having an average particle diameter of 300 nm or less and having a viscosity at 25 ° C. of 50 mPa · sec or less.   A cured product obtained by curing the photosensitive ink according to claim 1.