JPH0355483B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a novel photocurable resin composition. More specifically, the present invention relates to a photocurable resin composition containing a specific photopolymerization initiator, which is particularly suitable as an image forming material by laser beam scanning. Background Art In recent years, photocurable resin compositions have attracted attention not only as materials for photoresists, inks, paints, varnishes, and printing plates, but also as image-forming materials that use laser light and photosensitive materials that replace silver salts. has been done. In the photocurable resin composition used as such a material, it is important for its performance to increase the photosensitive speed as much as possible, and many studies have been conducted for this purpose. However, most of the research to date has focused on photopolymerization initiators that are active in ultraviolet light, and conventional ones have insufficient photosensitivity for laser beams, so they are not suitable for laser beam scanning. Therefore, in order to form images, it was necessary to expand the photosensitive wavelength range and dramatically increase the photosensitive speed. Conventionally, photopolymerizable resins sensitive to visible light have been prepared using various compositions, such as S having at least one trihalomethyl group and at least one chromophore moiety, in which an ethylenically unsaturated compound and a triazine ring are conjugated. -Those using a triazine compound as a photopolymerization initiator (Japanese Patent Application Laid-open No. 1973-36281), those using an unsaturated ketone conjugated with p-dialkylaminoallylidene as a photopolymerization initiator (Japanese Patent Laid-Open No. 155292-1989) Publications), those using a combination of a polycyclic quinone and a tertiary amine as a photopolymerization initiator (Japanese Unexamined Patent Publication No. 134692/1983), and those using an organic peroxide such as 1,10-oxyester and a thiapyrylium salt as a photopolymerization initiator. Photopolymerization initiators [Journal of the Chemical Society of Japan, No. 1, page 119 (1985
2003)], merocyanine dye or aromatic ketones and 2,4,6-trichloromethyl-1,3,5-triazine and 2-mercaptobenzimidazole as photopolymerization initiators [Journal of the Chemical Society of Japan, Vol.
No. 192 (1984)] have been proposed. However, although all of these photocurable resin compositions exhibit photosensitivity to light with longer wavelengths than conventional ones, they have low or almost no photosensitivity to long wavelengths of 600 nm or more. Another drawback is that it is not possible to use light sources such as HE-Ne lasers (633 nm) and semiconductor lasers (780 nm or more), which are advantageous in that they are small and stable, as laser light sources. On the other hand, a photocurable composition consisting of methylene blue, p-toluenesulfonic acid, and barium acrylate, which exhibits high photosensitivity to He-Ne lasers, has been proposed.・Engineering (Photogr.Sci.Eng.), Vol. 12, Page 177 (1968)], this material has the disadvantage of being water-soluble and not suitable for oil-soluble resin compositions. In addition, as an oil-soluble photocurable resin composition that is sensitive to long wavelength light sources such as He-Ne lasers or semiconductor lasers, combinations of porphyrins, azaporphyrins, or their metal complexes and diaryliodonium salts can be used. A composition using as a photopolymerization initiator has been proposed.
78422), these porphyrins have low photosensitivity to long wavelength light, and azaporphyrins such as phthalocyanines have low sensitization efficiency. In order to use it as a silver salt substitute material, even higher photosensitivity is desired. Problems to be Solved by the Invention The present invention overcomes the drawbacks of such conventional photocurable resin compositions, has excellent photosensitivity to long wavelength light of 600 nm or more, and has He-Ne The purpose of this invention is to provide a photocurable resin composition that can use light sources such as lasers and semiconductor lasers. Means for Solving the Problems As a result of extensive research to develop a photocurable resin composition that has excellent photosensitivity to long wavelength light of 600 nm or more, the present inventors found that photopolymerization started. It has been discovered that the above object can be achieved by using a combination of a tetrabenzoporphyrin with a specific structure or a metal complex thereof and an electron-accepting radical generator as an agent, and based on this knowledge, the present invention has been developed. It was completed. That is, the present invention provides (A) a compound having at least one polymerizable ethylenically unsaturated bond; and (B)
In the photocurable resin composition comprising a photopolymerization initiator, as the photopolymerization initiator, (a) the general formula (R in the formula is a hydrogen atom, an alkyl group, or an aromatic residue with or without a substituent, and each benzene ring may or may not have a substituent, and A photocurable resin characterized by using a combination of a tetrabenzoporphyrin (which may have another condensed benzene ring) or a metal complex thereof, and (b) an electron-accepting radical generator. A composition is provided. The present invention will be explained in detail below. In the composition of the present invention, at least one polymerizable ethylenically unsaturated bond used as component (A)
In addition to vinyl monomers, compounds having
It may be an oligomer or a high molecular weight compound, such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, acrylamide, methacrylamide, diacetone acrylamide, 2-hydroxyethyl acrylate, N-
High-boiling monomers such as vinyl carbazole and N-vinylpyrrolidone, ethylene glycol, diethylene glycol, 1,3-propanediol,
di- or polyacrylic esters or polymethacrylic esters such as 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,10-decanediol, trimethylolethane, pentaerythritol, sorbitol, mannitol, Other examples include, but are not limited to, acrylated or methacrylated epoxy resins, polyester acrylate oligomers, acrylated or methacrylated urethane oligomers, and acroleinated polyvinyl alcohol. As the photopolymerization initiator of component (B) in the composition of the present invention, one consisting of a combination of a tetrabenzoporphyrin represented by the above general formula () or a metal complex thereof and an electron-accepting radical generator is used. It will be done. R in the tetrabenzoporphyrins represented by the general formula () is a hydrogen atom, an alkyl group, or an aromatic residue such as a phenyl group, a naphthyl group, or a pyridyl group, and this aromatic residue has no substituent. It may have a substituent or it may have no substituent. Each benzene ring may or may not have a substituent, and examples of the substituent include a halogen atom, a lower alkyl group having 1 to 5 carbon atoms, a lower alkoxy group, an alkoxycarbonyl group,
Examples include carboxyl group, nitro group, amino group, sulfone group, etc., and one or more of these substituents may be introduced into each benzene ring. Furthermore, each benzene ring may be fused with another benzene ring to form a naphthalene ring. Specific examples of such tetrabenzoporphyrins include unsubstituted tetrabenzoporphyrin, meso-phenyl group tetrabenzoporphyrin in which at least one meso position is substituted with a phenyl group, and naphthyl group in which at least one meso position is substituted with a phenyl group. meso-naphthyltetrabenzoporphyrin substituted with a group, meso-pyridyltetrabenzoporphyrin substituted with a pyridyl group in at least one meso position, 5,5′,5″,5-tetra-t-butyltetrabenzo Porphyrin, 4, 6, 4′, 6′, 4″, 6″,
4,6-octamethyltetrabenzoporphyrin, 5,5′,5″,5-tetraethoxytetrabenzoporphyrin, meso-methyltetrabenzoporphyrin substituted with a methyl group at least one meso position, meso position meso-benzyltetrabenzoporphyrin in which at least one of the meso positions is substituted with a benzyl group, meso-tolyltetrabenzoporphyrin in which at least one meso position is substituted with a tolyl group, and tetranaphthoporphyrin in which a benzene ring is further bonded as a condensed ring. Examples of metal complexes of tetrabenzoporphyrins include the above-mentioned tetrabenzoporphyrins and Mg, Zn, Cd, Pd, Ni, Co, Cu, Pb
complexes with divalent metal atoms such as Al, In, etc. with vertically coordinated hydroxyl groups and halogen atoms,
Examples include complexes with trivalent metal atoms such as Ga, Fe, and Cr or tetravalent metal atoms such as Si and Sn, and complexes with tetravalent metal atoms such as V and Ti coordinated with oxygen atoms. I can do it. On the other hand, as the electron-accepting radical generator, which is another component constituting the photopolymerization initiator, a compound exhibiting a reduction potential of -1.5 eV or more in electrochemical measurement is particularly preferably used. Such compounds have the general formula (R ¹ and R ² in the formula are a hydrogen atom, a halogen atom, a lower alkyl group, a methoxy group, a cyano group, or a nitro group, respectively, X ^- is a halogen ion, BF ₄ ,
Diaryliodonium salt represented by PF ₆ or AsF ₆ [Macromolecules No. 10,
Page 1307 (1977)], general formula (In the formula, R ³ and R ⁴ are each an alkyl group, and R ¹ and X ^- have the same meaning as above.)
Polym.Sci) Volume 17, Page 2877 (1979)],
general formula (R ⁵ and R ⁶ in the formula are each an alkyl group or an aryl group, R ¹ and X ^- have the same meanings as above)
Phenacyl sulfoxonium salt represented by (European Patent No. 44274), general formula (R ¹ , R ⁵ , R ⁶ and X ^- in the formula have the same meanings as above) A sulfoxonium salt represented by (In the formula, R ⁷ , R ⁸ and R ⁹ are each a methyl group or a trihalogenated methyl group.) Triazine compounds represented by the following can be mentioned. Examples of diaryliodonium salts represented by the general formula () include diphenyliodonium, ditolyliodonium, phenyl(p-anisyl)iodonium, bis(m-nitrophenyl)iodonium, and bis(p-tert-butylphenyl)iodonium. Examples of the phenacylsulfonium salts represented by the general formula () include iodonium chloride, bromide, borofluoride salt, hexafluorophosphate salt, hexafluoroarsenate salt, etc., such as dimethylphenacylsulfonium, phenacyltetramethylenesulfonium, Examples of the phenacylsulfoxonium salt represented by the general formula () include chloride, bromide, tetrafluoroborate salt, hexafluorophosphate salt, hexafluoroarsenate salt, etc. such as p-chlorophenacylsulfonium.
For example, dimethylphenacyl sulfoxonium salt,
chloride, bromide, and tetrafluoroporate salts such as diphenyl phenacyl sulfoxonium;
Sulfoxonium salts represented by the general formula () include hexafluorophosphate salts, hexafluoroarsenate salts, etc.; Examples of the triazine compound represented by the general formula () include fluoroborate salt, hexafluorophosphate salt, hexafluoroarsenate salt, etc., such as 2,4,6-tris(trichloromethyl)triazine, 2,4,6- Examples include tris(tribromomethyl)triazine, 2,4-bis(trichloromethyl)-6-methyltriazine, and the like. Regarding the usage ratio of the ethylenically unsaturated compound as the component (A) and the photopolymerization initiator as the component (B) in the composition of the present invention, the weight of the tetrabenzoporphyrin or its metal complex and the ethylenically unsaturated compound is determined. The ratio is usually chosen to be in the range 1:5 to 1:500. The ratio of the tetrabenzoporphyrins or their metal complexes to the electron-accepting radical generator is usually such that the weight ratio is 10:1 to 1:10, preferably 2:1 to 1:5. Selected based on percentage. If desired, the photocurable resin composition of the present invention may contain various additives conventionally used in photocurable resin compositions, such as binders, thermal polymerization inhibitors, plasticizers, and the like. Effect The mechanism of sensitized decomposition of the electron-accepting radical generator by tetrabenzoporphyrins or its metal complex in the composition of the present invention is not necessarily clear, but the excitation formed by the sensitizer and the initiator Due to the electron transfer reaction from the plexus [The Journal of Imaging Technology (J.Imaging.Tech.) Vol. 11, No. 4, No.
Page 146 (1985)], a certain degree of explanation is possible. In other words, the oxidation potential in electrochemical measurements of tetrabenzoporphyrins or their metal complexes is approximately in the range of 0.5 eV to 1.0 eV, and the excitation energy level is
Since it is in the range of 1.5 eV to 2.0 eV, if the reduction potential of the electron-accepting radical generator that is sensitized and decomposed by electron transfer is lower than -1.5 eV, the formula △G = (Eox - Ered) -Eex...() (Eox is the oxidation potential of the tetrabenzoporphyrins or its metal complex, Ered is the reduction potential of the radical generator, Eex is the excitation energy level of the tetrabenzoporphyrins, △G is free ΔG, which is an energy change), has a positive value. A positive value of ΔG indicates that the reaction system is endothermic, and means that the electron-accepting radical generator is difficult to be decomposed by sensitization. Effects of the Invention The photocurable resin composition of the present invention can be used as a light source,
In addition to being able to use high-pressure mercury lamps, ultra-high-pressure mercury lamps, high-pressure xenon lamps, halogen lamps, fluorescent lamps, etc., it shows high sensitivity to long wavelength light of 600 nm or more, and is particularly sensitive to industrially useful laser light.
Gas lasers such as He-Cd, Ar, He-Ne, and Kr, and semiconductor lasers of Ga, Al, and As can be used because they exhibit extremely high sensitivity of 0.1 mJ/cm ² to several mJ/cm ² In addition, since it does not exhibit reciprocity law failure behavior that is likely to occur especially when exposed to high-intensity irradiation, it can be used for image forming materials by laser beam scanning, such as plate-making materials for lithography and letterpress, photoresists for printed wiring plates, materials for creating dry film reliefs, and non-silver salts. It can be applied to a wide range of fields, such as image creation materials and photosensitive materials for holograms. Examples Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples in any way. Examples 1 to 4 Copolymers having chloromethylstyrene units and methyl methacrylate units in a molar ratio of 1:1
1.35g and 3,4-dihydro-2H-pyran-2
- After reacting 1.86 g of sodium carboxylate in 20 ml of dimethylacetamide at 60 to 80°C for 1 hour, the reaction solution was poured into a mixed solvent of water and methanol (weight ratio 2:1), and the polymer was precipitated. This polymer was filtered off, thoroughly washed with methanol, dissolved in dioxane, and purified by precipitation in methanol. The resulting polymer was dissolved in dioxane,
A solution with a concentration of 5% by weight was prepared, and diphenyliodonium hexafluorophosphate having a reduction potential of -0.26 eV and various tetrabenzoporphyrins shown in Table 1 were each added at 4% by weight based on the polymer. A photosensitive solution was prepared. Next, this solution was spin-coated onto an anodized aluminum plate to a thickness of about 1 μm.
A 122 mW/wave with a beam diameter of 1.0 mm is applied to this photosensitive layer.
We irradiate a He-Ne laser beam of 633 nm in cm ² and measure the amount of energy that gives the same diameter as the beam diameter.
Sensitivity was determined. The results are shown in Table 1.

[Table] Examples 5 to 8 Meso-phenyltetrabenzoporphyrin zinc complex and various electron-accepting radical generators shown in Table 2 were added to polymer solutions prepared in the same manner as in Examples 1 to 4, respectively. 4% by weight based on polymer
After each addition was made to prepare a photosensitive solution, it was evaluated in the same manner as in Examples 1 to 4. The results are shown in Table 2.

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【table】

Claims (1)

[Scope of Claims] 1. A photocurable resin composition comprising (A) a compound having at least one polymerizable ethylenically unsaturated bond, and (B) a photopolymerization initiator; As an initiator, (a) general formula (R in the formula is a hydrogen atom, an alkyl group, or an aromatic residue with or without a substituent, and each benzene ring may or may not have a substituent, and A photocurable resin characterized by using a combination of a tetrabenzoporphyrin (which may have another condensed benzene ring) or a metal complex thereof, and (b) an electron-accepting radical generator. Composition. 2. The composition according to claim 1, wherein the electron-accepting radical generator exhibits a reduction potential of -1.5 eV or more in electrochemical measurements.