JPH09208610A - Photopolymerization initiator sensitizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a photopolymerizable initiator sensitizer which has high solubility in a solvent and high sensitivity and is useful as a sensitizing dye or the like of a recording material by comprising a styryl dye having a particular structure as an effective component. SOLUTION: A styryl dye represented by the formula (wherein R1 and R2 represent an optionally branched 4C or higher alkyl; R3 represents H, an alkyl, a hydroxyl group, an alkoxy, or a halogen, provided that R2 may combine with R3 located at the o-position relative to the nitrogen atom to form an ethylene or propylene group; and (n) is 1 or 2) is used as an effective component to constitute a photopolymn. initiator sensitizer. This sensitizer, a photopolymn. initiator (e.g. di-tert-butyldiperoxy isophthalate), a photopolymerizable compd. (e.g. ethylene glycol dimethacrylate), and a binder resin (e.g. polymethyl methacrylate) are mixed together to prepare a photopolymerizable compsn. Use of the photopolymerizable compsn. enables high-speed scanning recording using a light source in a visible region of 450 to 550nm.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a photopolymerization initiation type sensitizer comprising a styryl type dye having a specific structure.

[0002]

2. Description of the Related Art A photopolymerizable composition is a material that changes its physical properties in a light-irradiated part and a non-irradiated part by receiving light energy.
Printing, micro processing such as VLSI, printed circuit formation, U
It is used in a wide range of fields such as V-curing paints, inks, and hologram recordings, and its use is being further expanded. This composition is basically composed of a photopolymerization initiator, a photopolymerizable compound and a binder resin, and usually has sensitivity in the ultraviolet region, and the g-line and i-line of mercury lamps and the violet of high-power argon. Image recording is performed using an external oscillation line or the like.

However, in recent years, technical development using a visible light laser, which is small, inexpensive, and highly safe, has been actively promoted, instead of the ultraviolet light which is a large and expensive irradiation device and is dangerous to handle. For this reason, it is essential to use a sensitizing dye that gives sufficient sensitivity to various visible laser oscillation wavelengths. The characteristics of such a sensitizing dye include (1) excellent solubility in a solvent, (2) large absorption coefficient at the wavelength of recording light,
(3) The photosensitive wavelength is well matched with the wavelength of the recording light,
(4) High sensitivity, (5) Good storage stability, (6) Good compatibility with other components, etc. are required.

Various types of dyes have been proposed as dyes useful in this technique. For example, JP-A-63
No. 23901, No. 64-48059, JP-A-3-200.
Coumarin-based dyes for 785 are disclosed in JP-A-58-2980.
3, JP-A-2-189548 and JP-A-4-102855, cyanine dyes, JP-A-54-151024 and JP-A-3-39747, merocyanine dyes, and JP-A-57.
No. 21,401, JP-A-2-69 and JP-A No. 4-14083 propose styryl dyes, and JP-A-60-76503 proposes xanthene dyes. However, these dyes have merits and demerits in terms of characteristics, and it is the fact that few of them are sufficiently satisfactory.

[0005]

In the technical field of recording an image with a visible laser using a photopolymerizable composition, in order to save labor, shorten the delivery time, and reduce the production of a wide variety of products, high-speed computer processing is required. There is a growing need for scanning exposure recording and low power laser recording. Therefore, a sensitizing dye having various properties which are more and more practical is demanded.

Among the known dyes, the present inventor has disclosed in Japanese Patent Application Laid-Open No. 4-1
Focusing on the styryl dyes described in JP-A Nos. 4083 and 5-341702, various characteristics as a high-sensitivity material for an argon laser were evaluated and examined. As a result, it was found that although this dye has a fairly good sensitivity, it has poor solubility in a solvent and cannot be put to practical use.

The inventor of the present invention has further studied earnestly with the aim of maintaining or improving sensitivity and imparting high solubility. as a result,
It was found that a styryl dye having a limited range of structure having a specific substituent has the above-mentioned properties as a photopolymerization initiation sensitizer and is practically useful, and thus completed the present invention.

[0008]

The present invention relates to a photopolymerization initiation sensitizer comprising a styryl dye represented by the following general formula (I).

Embedded image In the formula, R ₁ and R ₂ each independently represent an alkyl group having 4 or more carbon atoms and which may be branched, and R ₃ represents hydrogen, an alkyl group, a hydroxyl group, an alkoxy group or halogen. Further, R ₂ and R _{3 in the} ortho position with respect to the nitrogen atom may form an ethylene group or a propylene group. n represents 1 or 2.

Examples of the alkyl group of R ₁ and R ₂ include
Butyl group, isobutyl group, sec-butyl group, tert
-Butyl group, amyl group, isoamyl group, hexyl group, heptyl group, octyl group, decyl group, dodecyl group, octadecyl group, and the like. Examples of the alkyl group of R ₃ include a methyl group, an ethyl group and a propyl group, and examples of the alkoxy group include a methoxy group, an ethoxy group and a propoxy group. Examples of halogen include chlorine, fluorine, bromine and iodine.

Examples of the photopolymerization initiator used in combination with the sensitizing dye of the present invention include various organic peroxides, triazine compounds represented by 2,4,6-trichloromethyl-s-triazine, benzoin alkyl ethers, and bisimidazoles. ,
Metallocenes such as iron-allene complexes and titanocene compounds,
Examples thereof include N-phenylglycine and diphenyliodonium salt. Further, a multi-component initiator obtained by combining these several types may be used. As examples of organic peroxides, peroxyesters include di-t-butyldiperoxyisophthalate, 3,3'4,4'-tetrakis (t-butyldioxycarbonyl) benzophenone, and dialkylperoxides. 2,5-dimethyl-
2,5-bis (t-butyldioxy) -3-hexane,
As di-t-butyl peroxide and hydroperoxide, 2,5-bis (hydroperoxy) -2,5-
Dimethylhexane, t-butylhydroperoxide,
As peroxyacetal, butyl-4,4-bis (t-butyldioxy) valerate, 1,1-bis (t
-Butyldioxy) -3,3,5-trimethylcyclohexane, and examples of ketone peroxide include ethyl methyl ketone peroxide.

The photopolymerizable compound is composed of a photopolymerizable or photocrosslinkable monomer, oligomer, prepolymer or a mixture thereof having at least one ethylenically unsaturated double bond in one molecule. Examples of such compounds include ethyl acrylate, hydroxyethyl acrylate, ethylene glycol dimethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, polyester methacrylate, polyurethane methacrylate,
Mention may be made of compounds usually used in this technical field, such as epoxy methacrylate.

An example of the binder resin is poly-N-
Vinylpyrrolidone, polyvinyl acetate, polyvinyl butyral, polyvinylcarbazole, polystyrene,
Examples thereof include polymethylmethacrylate, polyethylene oxide, polybutylmethacrylate, styrene-maleic acid ester, polymethylmethacrylate-methacrylic acid-based resin, poly-N-vinylpyrrolidone-glycidylmethacrylate-based resin, and the like.

The sensitizing dye according to the present invention is used in a proportion of 0.05 to 10 times with respect to the photopolymerization initiator, and a binder resin is added in a proportion of 0 to several hundred times with respect to the mixture thereof. A polymerizable composition is prepared. If necessary, additives such as a thermal polymerization inhibitor and a plasticizer may be added to the composition.

Next, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples. Specific examples of the sensitizing dye of the present invention include the following dyes.

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[Chemical 6]

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The styryl dye used in the present invention can be produced by a known method. The production of the dye will be described with reference to reference examples.

[0016]

[Reference Example] Synthesis of Dye 1 Obtained by dehydration condensation reaction of dehydroacetic acid and 4-dibutylaminobenzaldehyde

Embedded image 10 g of the intermediate represented by is reacted with concentrated hydrochloric acid at 130 ° C. for 3 hours. After the reaction, it was poured into 100 ml of water, neutralized with alkali, extracted with chloroform, and the solvent was distilled off under reduced pressure.

Embedded image 8.5 g of the pyrone compound represented by

Next, a pyrone compound 3 represented by Chemical formula 13
g) 1 g of malondinitrile and 12 ml of acetic anhydride are reacted at 140 ° C. for 4 hours. Dye 1 was obtained by purifying the obtained crude dye using a silica gel column.
2.5 g of a purified product of It has a maximum absorption wavelength of 486 nm in dichloromethane) and a melting point of 138-9 ° C.

Other dyes can be similarly synthesized.

Next, sensitivity measurement will be described. Photosensitive liquid formulation: Binder resin (XL-44) 100 parts Polyfunctional monomer (PETA) 100 parts Organic peroxide (BTTB) 8 parts Sensitizing dye 2 parts Ethyl cellosolve 900 parts

The above photosensitive solution was spin-coated on a surface-treated grained aluminum plate to form a photosensitive layer. An overcoat layer of polyvinyl alcohol was provided to avoid polymerization inhibition by oxygen. A gray scale is brought into close contact with this photosensitive layer so that light from a 150 W xenon lamp is sharp cut filter; Y-47 and interference filter; KL-49.
Light having a wavelength close to the oscillation wavelength of the argon laser extracted by passing the laser beam was similarly emitted, and light having a wavelength close to the oscillation wavelength of the second harmonic of the YAG laser extracted by passing the laser beam through Y-52 and KL-54 was irradiated. Thereafter, development was performed using an alkaline developer. The sensitivity was determined from the number of photocured steps using the following equation.

E (mJ / cm ² ) = Io (mJ / cm ²
S) × Tn × t (s) Tn: transmittance of the n-th step tablet t: exposure time Io: exposure intensity

Solubility Measurement The solubility was calculated by a colorimetric method using a saturated solution prepared by mixing a dye and a solvent, stirring the mixture at 20 ° C. for 3 hours, and filtering off excess dye.

Table 1 shows these results together with comparative examples. The maximum absorption wavelength of the dye in dichloromethane is also shown.

The substance names of the abbreviations and the structures of the comparative dyes are as follows. XL-44: acrylic acid-methacrylic acid ester copolymer PETA: pentaerythritol triacrylate BTTB: 3,3 ', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone

Comparative Dye 11 (DCM)

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As is clear from Table 1, the solubility of the dye of the present invention is one digit larger than that of the known comparative dye. Thus, in the general formula (I), when the number of carbon atoms of the terminal alkyl group is 4 or more, a remarkable improvement in solubility is observed. As a result, these dyes have practically sufficient solubility. Therefore, the photosensitive solution can be easily prepared by stirring at room temperature. On the other hand, in the case of the known comparative dye, it is necessary to stir under heating to obtain the use concentration. Further, since the dye of the present invention exhibits high solubility at least 5 times higher than the actual use concentration, it is possible to provide a uniform photosensitive film even after coating and film formation with a photosensitive solution. However, since the comparative dye has a barely soluble property with respect to the actual concentration used, a supersaturated solution is prepared by heating and a film is formed using this. For this reason, there is a problem in terms of quality, such as the deposition of dye crystals in the film after film formation.
Further, it is necessary to increase the ratio of the dye depending on the material composition of the photopolymerization initiation composition, but there is a disadvantage that it becomes more and more difficult to adapt to such requirements.

The absorption maximum wavelength of the dye of the present invention is shifted by about 17 nm longer than that of the comparative dye, and the photosensitive wavelength is better matched with the wavelength of the argon laser which is the recording light, and the absorption coefficient at the recording light wavelength is Can be large. From these facts, the dye of the present invention is expected to exhibit the same or higher sensitivity as the comparative dye, and it becomes possible to reduce the amount of the dye used. Furthermore, since the photosensitive wavelength range is extended to a longer wavelength range, the sensitivity becomes higher with respect to the second harmonic 532 nm light of the YAG laser.

[0028]

EFFECTS OF THE INVENTION The sensitizing dye according to the present invention has excellent solubility in a solvent and compatibility with each component, and has high sensitivity. Therefore, high speed scanning recording with a light source in the visible range of 450 to 550 nm is possible, Laser direct platemaking PS
It is extremely useful as a sensitizing dye for materials such as printing plates, dry film resists, digital color proofs and hologram recording materials.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigeo Yasui 566-139 Fujita Nishiki, Okayama City, Okayama Prefecture

Claims (1)

[Claims] 1. A photopolymerization initiation sensitizer comprising a styryl dye represented by the following general formula (I): (In the formula, R ₁ and R ₂ each independently have 4 carbon atoms.
Represents an alkyl group which may be branched, R ₃ is hydrogen,
It represents an alkyl group, a hydroxyl group, an alkoxy group or halogen. Further, R ₂ and R _{3 in the} ortho position with respect to the nitrogen atom may form an ethylene group or a propylene group. n represents 1 or 2. ).