JPH1020494A - Photopolymerizable composition, photosensitive original plate using the composition and its exposing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve sensitivity for light in a visible region, to easily form a uniform coating film and to improve stability of the film with time by incorporating an ethylene-type unsatd. compd., a titanocene compd. and a specified rhodamine dye. SOLUTION: This compsn. contains an ethylene-type unsatd. compd. (a), a titanocene compd. (b) and a rhodamine dye (c) expressed by formula. In the formula, R<1> to R<7> are independently hydrogen atoms, alkyl groups, alkenyl groups, alkynyl groups, aryl groups, cyano groups or halogen atoms, and A represents BF4 <-> , ClO4 <-> or PF6 <-> . The amt. of the compd. (b) is 0.01 to 50 pts.wt. to 100 pts.wt. of the compd. (a). The amt. of the dye (c) is 0.01 to 50 pts.wt. to 100 pts.wt. of the compd. (a). The compd. (a) is a monomer which is suitable for the chain-growing addition reaction initiated by radicals. The compd. (a) is preferably an ester of polyol and (meth)acrylic acid considering that it gives good performance such as developing property. The compd. (b) is the initiator for the photopolymn. of the compd. (a).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a photopolymerizable composition,
More particularly, the present invention relates to a photopolymerizable composition having high photosensitivity to light in a visible region, a photosensitive master using the same, and a method of exposing the same.

[0002]

2. Description of the Related Art Photopolymerizable compositions are used in many applications, for example, in commercial applications such as printing, copying, and resist formation. The photopolymerizable compositions used for these applications generally comprise an ethylenically unsaturated compound or other polymerizable compound, a photoinitiator, and preferably a solvent-soluble, photo- or alkali-soluble organic polymer binder. Contains. These photopolymerizable compositions are photosensitive to ultraviolet light.

Recently, image forming techniques have been required to perform scanning exposure using a visible light, an argon laser, or an FD-YAG laser instead of ultraviolet light as a light source. However, most of the photopolymerizable compositions described above cannot be used because the photoinitiator used is not activated by light other than in the ultraviolet region, and is not sensitive to light in the visible region. Therefore, a photopolymerizable material having high photosensitivity to light in the visible region is required, and development of a photoinitiator having high sensitivity to light in the visible region is desired.

JP-A-54-155292 discloses a photoinitiator system containing a hexaarylbisimidazole as a photoinitiator having high sensitivity to light in the visible region. Discloses a system of a photoinitiator of an active halogen compound and a 3-keto-substituted coumarin compound, and JP-A-56-4604 discloses a system of a photoinitiator of a 3-keto-substituted coumarin compound and N-phenylglycine. , JP 6
Japanese Patent Application Laid-Open No. 1-97650 discloses a combination of a 3-keto-substituted coumarin compound and a quinazolinone derivative.
No. 23603 discloses a combination of a hexaarylbisimidazole and a 3-keto-substituted coumarin compound, respectively. However, these photoinitiator systems have insufficient sensitivity to light in the visible region.

Japanese Patent Application Laid-Open No. 2-127404 discloses a photosensitive resin composition containing a rhodamine dye and a titanocene compound as a photopolymerizable composition suitable for recording with a laser beam in the visible region. The dye has a halogen anion, particularly a chlorine anion, as a counter anion, and has high water solubility and crystallinity. For this reason, there is a problem that the solubility in other components in the photosensitive resin composition or a solvent used for forming a coating film is low, and a uniform coating film cannot be obtained, or a dye is deposited over time.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks, and has as its object to provide high sensitivity to light in the visible region, facilitate formation of a uniform coating film, and provide stability with time. An object of the present invention is to provide a good photopolymerizable composition, a photosensitive master using the same, and a method for exposing the same.

[0007]

The present invention has been made as a result of intensive studies on photoinitiator yarns for the purpose of solving the above problems.
The photopolymerizable composition containing a titanocene compound as a photoinitiator and a rhodamine dye having a specific structure has high sensitivity to light in the visible region, facilitates uniform coating film formation, and results in deposition during operation. I knew there wasn't. That is, the present invention provides a light comprising: (a) at least one ethylenically unsaturated compound; (b) a titanocene compound; and (c) a rhodamine dye represented by the following general formula (I). It is a polymerizable composition and a photopolymerizable composition containing a glycine derivative to further enhance sensitivity.

Embedded image(Where R¹~ R⁷Are each independently a hydrogen atom,
Kill, alkenyl, alkynyl, aryl,
A represents an ano group or a halogen atom, and A represents BF_Four ^-, Cl
O_Four ^-, PF₆ ^-Is shown. )

In a preferred embodiment, the content of the titanocene compound is 0.01 to 50 parts by weight based on 100 parts by weight of the ethylenically unsaturated compound, and the content of the rhodamine dye is ethylenic. The content of the glycine derivative is 0.01 to 50 parts by weight based on 100 parts by weight of the unsaturated compound.
0 to 20 parts by weight with respect to parts by weight. Further, the present invention is a photosensitive original plate, wherein a photosensitive layer containing the above-mentioned photopolymerizable composition is formed on a substrate, and preferably, oxygen barrier protection is further provided on the photosensitive layer. A layer is formed. The present invention also provides an argon ion laser, an FD
-An exposure method comprising exposing the photosensitive original using a -YAG laser or a helium-neon laser.

Next, the present invention will be described in detail. The first component, the ethylenically unsaturated compound (a), is a monomer suitable for a free radical initiated chain growth addition reaction.
Such an ethylenically unsaturated compound is not particularly limited, but is preferably an ester of a polyol and (meth) acrylic acid from the viewpoint of improving the developability and the performance of the cured coating film. Such esters include, for example, pentaerythritol triacrylate, polyethylene glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate,
Trimethylolpropane triacrylate, trimethylolpropane trimethacrylate and the like. These ethylenically unsaturated compounds (a) may be used alone or in combination of two or more.

The titanocene compound (b) as the second component
Is an initiator for photopolymerizing the ethylenically unsaturated compound (a), and is preferably a titanocene compound represented by the following general formula (II).

[0011]

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(Wherein R ⁸ and R ⁹ each independently represent a substituted or unsubstituted cyclopentadienyl group;
R ¹⁰ and R ¹¹ each independently represent a substituted or unsubstituted phenyl group. )

In the above formula (II), the substituted cyclopentadienyl group is preferably a cyclopentadienyl group substituted with an alkyl group or an alkoxy group.
The substituted phenyl group preferably refers to a phenyl group substituted with a halogen atom, an alkoxy group, a heterocyclic group and / or an alkyl group.

The alkyl group preferably has 1 carbon atom.
10 to 10 may be linear or branched, for example, methyl,
Ethyl, n-propyl, isopropyl, n-butyl, s
ec-butyl, tert-butyl and the like. Further, a halogen atom is a fluorine atom, a chlorine atom, a bromine atom or an iodine atom.

The alkoxy group preferably has 1 to 8 carbon atoms and may be linear or branched. For example, methoxy, ethoxy, n-propoxy, isopropoxy, n-
Butoxy, sec-butoxy, tert-butoxy and the like.

The heterocyclic group is a three or more-membered ring such as a nitrogen-containing heterocyclic group, a sulfur-containing heterocyclic group, and an oxygen-containing heterocyclic group. Examples thereof include pyrrolyl, imidazolyl, pyrazolyl, tetrazolyl, Pyridyl, pyrimidyl, furyl, oxazolyl, isoxazolyl, thiophenyl, thiazolyl, isothiazolyl and the like.

In the above general formula (II), preferably,
R⁸, R⁹Are each independently an alkyl group or an alk
A cyclopentadienyl group substituted with a oxy group or
A substituted cyclopentadienyl group,^Ten, R¹¹Is
Each independently halogen atom, alkoxy group, heterocycle
A phenyl group substituted with a group and / or an alkyl group
is there. More preferably, R⁸, R⁹Are independent
A cyclopentadienyl group substituted with an alkyl group
Is an unsubstituted cyclopentadienyl group; ^Ten, R¹¹
Are each independently a halogen atom, an alkoxy group and
And / or a phenyl group substituted by a nitrogen-containing heterocyclic group
is there. Specific examples of such a titanocene compound (b) are described below.
Shown below.

[0018]

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[0019]

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[0020]

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[0021]

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[0022]

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These titanocene compounds are used alone or in combination of two or more. The content of the titanocene compound (b) is preferably 0.01 to 50 parts by weight, more preferably 0.1 to 30 parts by weight, based on 100 parts by weight of the ethylenically unsaturated compound. When the content is less than 0.01 part by weight, the photocurability is insufficient, and when the content is more than 50 parts by weight, the photocurability is undesirably lowered.

The rhodamine dye (c) as the third component
Acts as a photosensitizer and is represented by the following general formula (I).

[0025]

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(Where R¹~ R⁷Are each independently water
Element atom, alkyl group, alkenyl group, alkynyl group,
Represents a reel group, a cyano group or a halogen atom;
F_Four ^-, ClO_Four ^-, PF₆ ^-Is shown. )

In the above formula (I), the alkyl group preferably has 1 to 12 carbon atoms and may be linear or branched. For example, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec. -Butyl, tert-
Butyl, n-pentyl, n-hexyl and the like.

The alkenyl group preferably has 2 to 14 carbon atoms and may be linear or branched. For example, ethenyl, 2-propenyl, 3-butenyl, 4-pentenyl,
5-hexenyl, 6-heptenyl, 7-octenyl and the like.

The alkynyl group preferably has 2 to 14 carbon atoms and may be linear or branched, for example, ethynyl, 2-propynyl, 3-butynyl, 4-pentynyl,
5-hexynyl, 6-heptynyl, 7-octynyl and the like.

The aryl group preferably has 6 carbon atoms.
And alkyl-substituted phenyl such as phenyl, naphthyl and tolyl, and halogen-substituted phenyl such as chlorophenyl. As the halogen atom, a fluorine atom,
Examples include a chlorine atom, a bromine atom, or an iodine atom.
In the above formula, preferably, R ^{1 to} R ⁷ each independently represent a hydrogen atom, an alkyl group or a halogen atom, and more preferably, R ^{1 to} R ⁷ each independently represent a hydrogen atom or an alkyl group. Specific examples of such a xanthene dye (c) are shown below.

[0031]

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[0032]

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[0033]

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[0034]

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[0035]

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[0036]

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[0037]

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[0038]

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[0039]

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These xanthene dyes are used alone or in combination of two or more. The content of the xanthene dye (c) is preferably 0.01 to 50 parts by weight, more preferably 0.1 to 50 parts by weight, based on 100 parts by weight of the ethylenically unsaturated compound. When the content is less than 0.01 part by weight, the photocurability is insufficient, and when the content is more than 50 parts by weight, the photocurability is undesirably lowered.

The photopolymerizable composition of the present invention has higher sensitivity by containing a glycine derivative. Preferred glycine derivatives are represented by the following general formula (III).

[0042]

Embedded image (In the formula, R ^{12 to} R ¹⁸ each independently represent a hydrogen atom, an alkyl group, an aryl group, a haloalkyl group, an acyl group, an alkoxy group, an alkoxycarbonyl group, a halogen atom, or a cyano group.)

The alkyl group preferably has 1 to 10 carbon atoms and may be linear or branched. For example, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-
Nonyl, n-decyl, n-undecyl, n-dodecyl and the like can be mentioned. The aryl group preferably includes phenyl, naphthyl, tolyl and the like having 6 to 12 carbon atoms.

As the haloalkyl group, the alkyl portion thereof preferably has 1 to 8 carbon atoms and may be linear or branched. For example, chloromethyl, fluoromethyl, dichloromethyl, difluoromethyl, trifmolomethyl, trichloromethyl , Chloroethyl and the like.

As the acyl group, the alkyl portion thereof preferably has 1 to 10 carbon atoms and may be linear or branched, and examples thereof include acetyl, ethylcarbonyl, propylcarbonyl, butylcarbonyl, pentylcarbonyl, hexylcarbonyl and the like. .

As the alkoxy group, the alkyl part thereof preferably has 1 to 10 carbon atoms and may be linear or branched, and examples thereof include methoxy, ethoxy, propoxy, butoxy and pentyloxy. An alkoxycarbonyl group means that the alkyl portion thereof preferably has 1 to 1 carbon atoms.
0 may be linear or branched, for example, methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl,
Butoxycarbonyl, pentyloxycarbonyl and the like. The halogen atom is a fluorine atom, a base atom, a bromine atom or an iodine atom.

Specific examples of such glycine induction include:
For example, N-phenylglycine, N- (p-methylphenyl) glycine, N- (m-trifluoromethylphenyl) glycine, N- (p-trifluoromethylphenyl) glycine, N- (p-acetylphenyl) glycine , N- (m-acetylphenyl) glycine, N- (p
-Methoxyphenyl) glycine, N- (m-methoxyphenyl) glycine, N- (p-methoxycarbonylphenyl) glycine, N- (m-chlorophenyl) glycine, N- (o-chlorophenyl) glycine, N- (p-
Fluorophenyl) glycine, N- (p-cyanophenyl) glycine, N- (m-cyanophenyl) glycine,
N-methyl-N-phenylglycine and the like.

These glycine derivatives may be used alone or in combination of two or more. The content of the glycine derivative is
0.01 to 20 parts by weight, preferably 0.1 to 2 parts by weight, based on 100 parts by weight of the ethylenically unsaturated compound.
0 parts by weight. When the content is less than 0.01 part by weight, the effect of the compounding is insufficient, and when the content is more than 20 parts by weight, the photocurability is rather lowered, which is not preferable.

The photopolymerizable composition of the present invention may further contain a cyclic diketone compound represented by the following general formula (IV).

[0050]

Embedded image (In the formula, R ¹⁹ represents a hydrogen atom, a substituted or unsubstituted alkyl group or a substituted or unsubstituted aralkyl group, and G represents a cyclic divalent organic group.)

This cyclic diketone compound is a cyclic β-digalbonyl compound having an active methylene group having an unstable hydrogen atom. In the above general formula (IV), the alkyl group preferably has 1 to 12 carbon atoms and may be linear or branched, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, te
rt-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl and the like. The substituted alkyl group preferably refers to an alkyl group substituted with a hydroxyl group, a cyano group, a halogen atom, an alkoxy group, a thioether group, an aryloxy group, or the like.

As the aralkyl group, the aryl portion thereof preferably has 6 to 10 carbon atoms, and the alkyl portion preferably has 1 to 12 carbon atoms and may be linear or branched, for example, benzyl, phenethyl, phenylpropyl and the like. Is mentioned. The substituted phenyl preferably refers to a phenyl group substituted with a hydroxyl group, a cyano group, a halogen atom, an alkoxy group, an alkyl group, or the like. The cyclic divalent organic group completes the diketone ring. This moiety may contain heteroatoms such as nitrogen, oxygen and sulfur.

Specific examples of such a cyclic diketone compound include, for example, 5,5-dimethyl-1,3-cyclohexanedione, 2-methyl-1,3-cyclohexanedione, 2-methyl-1,3-cyclopentanedione. , 2,
4-diethyl-1,3-cyclobutanedione, 2-methyl-1,3-cyclobutanedione, 5-methyl-2-thiobarbituric acid, barbituric acid, 3-ethyltetronic acid, 2,4-dimethyl-3 -Oxo-5-hydroxy-5-methoxypentenoic acid δ-lactone, 1,3,5-
Trimethylbarbituric acid, 1,3-dimethyl-5-ethylbarbituric acid, 2-methyldimedone, 1,3-indandione, 2-methylindandione, bis- [5
-(1,3-dimethylbarbituryl)] methane, 1,5
-Diphenyl-3- [2- (phenylthio) ethyl]-
2,4-pyrrolidinedione, 1-phenyl-3,5-diketo-4-n-butyltetrahydropyrazole, 2,2
-Dimethyl-m-dioxane-4,6-dione, 2,
2,5-trimethyl-m-dioxane-4,6-dione and the like.

These cyclic diketone compounds are used alone or in combination of two or more. The content of the cyclic diketone compound is preferably 20 parts by weight or less, more preferably 0.1 part by weight, based on 100 parts by weight of the ethylenically unsaturated compound.
-20 parts by weight. If the content exceeds 20 parts by weight, the photocurability is rather lowered, which is not preferable.

The photopolymerizable composition of the present invention may further contain a thermoplastic high molecular weight organic polymer binder. Such polymer binder types include (i) copolyesters based on terephthalic acid, isophthalic acid, sebacic acid, adipic acid and hexahydroterephthalic acid, (ii)
Polyamide, (iii) vinylidene chloride copolymer, (i
v) ethylene / vinyl acetate copolymer, (v) cellulose ether, (vi) polyethylene, (vii) synthetic rubber, (viii) cellulose ester, (ix) polyvinyl acetate / acrylate and polyvinyl acetate /
Polyvinyl ester containing a methacrylate copolymer,
(X) polyacrylates and polyα-alkyl acrylate esters such as polymethyl acrylate and polyethyl methacrylate, (xi) copolymers of (meth) acrylic acid and (meth) acrylate, (xii) 4,0
A high molecular weight ethylene oxide polymer (polyethylene glycol) having a weight average molecular weight of 00 to 4,000,000, (xiii) polyvinyl chloride and a copolymer thereof,
(Xiv) polyvinyl acetal, (xv) polyformaldehyde, (xvi) polyurethane, (xvii) polycarbonate and (xviii) polystyrene.

Preferred photopolymerizable binders are those in which the unexposed photopolymerizable coating is soluble in a predominantly aqueous solution, for example an alkaline solution, but becomes relatively insoluble after exposure to actinic radiation. Polymer binders are preferred. Typically, polymers satisfying these requirements are carboxylated polymers such as methacrylic acid copolymers, acrylic acid copolymers, crotonic acid copolymers, and maleic acid, which are free carboxylic acid group-containing vinyl addition polymers. Copolymers and partially esterified maleic acid copolymers. Further, there are cellulose having a carboxyl group in a side chain, and a product in which a cyclic acid anhydride is added to a polymer having a hydroxyl group in a side chain.

The content of the organic polymer binder is preferably 100 parts by weight based on 100 parts by weight of the ethylenically unsaturated compound.
0 parts by weight or less, more preferably 200 parts by weight or less. If the content exceeds 1000 parts by weight, the photocurability is undesirably reduced.

Further, in order to prevent unnecessary thermal polymerization of the polymerizable ethylenically unsaturated compound during the production or storage of the photopolymerizable composition, a small amount of a thermal polymerization inhibitor is added to the photopolymerizable composition. It is preferred to add. Suitable thermal polymerization inhibitors include hydroquinone, p-methoxyphenol, di-tert-butyl-p-cresol, pyrogallol, di-tert-butylcatechol, benzoquinone, 2-mercaptobenzimidazole, N-nitrophenylhydroxyamine Cerium and the like. If necessary, an inert additive such as a non-polymerizable plasticizer, a dye, a pigment and a filler may be added to such an extent that the photopolymerizability is not significantly impaired. The addition amount of the thermal polymerization inhibitor is preferably 0.01 to 5% by weight based on the whole composition.

The photopolymerizable compositions of the present invention can be coated on a wide variety of substrates. Here, "substrate" means any natural or synthetic support, preferably one that can be present in the form of a flexible or rigid film or sheet. For example, the material can be a metal sheet or foil, a synthetic organic resin sheet or film, cellulose paper, fiberboard, or a composite of two or more of these materials. Specific materials include alumina plast aluminum, anodized aluminum, aluminum plast polyethylene terephthalate film, polyethylene terephthalate film,
Examples include an electrostatic discharge treated polyethylene terephthalate film, polyvinyl alcohol coated paper, cross-linked polyester coated paper, nylon, glass, cellulose acetate film and the like.

The particular material is generally determined by the relevant application purpose. For example, when a printed circuit is manufactured,
The material can be a plate coated with copper on fiberboard. In the manufacture of lithographic printing plates,
The material can be anodized aluminum.

In the present invention, the thickness of the photopolymerizable composition is from 0.1 to 250 μm, preferably from 0.5 to 50 μm.
m. The desired thickness depends on the application. On the layer of the photopolymerizable composition provided on the substrate, a protective layer made of a polymer having excellent oxygen barrier properties, such as polyvinyl alcohol, is provided in order to prevent a polymerization suppression effect due to oxygen in the air. Alternatively, a cover film such as a polyethylene terephthalate film may be laminated.

The photopolymerizable composition of the present invention has high sensitivity to actinic rays in a wide range from ultraviolet light to visible light. Therefore, light sources include ultra-high pressure, high pressure, medium pressure, and low pressure mercury lamps, chemical lamps, carbon arc lamps, xenon lamps, metal halide lamps, argon ion lasers, FDs
-A laser such as a YAG laser, a helium-neon laser, a helium-cadmium laser, a fluorescent lamp, a tungsten lamp, and sunlight can be used.

[0063]

EXAMPLES The present invention will be described in more detail with reference to the following examples, in which parts and percentages are by weight. A coating solution for a photosensitive layer having the following composition was applied on a transparent polyethylene terephthalate film having a thickness of 100 μm having an undercoat layer, and dried at 90 ° C. for 1 minute with a hot air drier to obtain a coating film having a thickness of 2 μm. Next, an aqueous solution of 7% polyvinyl alcohol (completely saponified, polymerization degree: 500) was applied thereon, and dried at 70 ° C. for 1 minute with a hot air drier to form a protective layer having a thickness of 1 μm, thereby preparing a sensitivity test piece. The state of the coating film was observed. Next, a gray scale film was superimposed on this sensitivity test piece, and scanning exposure was performed with 515 nm light of an argon ion laser.
Then, it was immersed in a 0.7% sodium carbonate solution at 30 ° C. for 10 seconds, washed with water to remove uncured portions, dried, and then examined for a complete curing step.

(Composition of photosensitive layer coating liquid)

[0065]

[Table 1]

[0066]

[Table 2]

[0067]

[Table 3]

[0068]

[Table 4]

[0069]

[Table 5]

[0070]

[Table 6]

[0071]

[Table 7]

[0072]

[Table 8]

[0073]

[Table 9]

[0074]

[Table 10]

[0075]

[Table 11]

Tables 12 and 13 show the measurement results of the test pieces obtained in Examples 1 to 7 and Comparative Examples 1 to 4.

[0077]

[Table 12]

[0078]

[Table 13]

By comparing Examples 1 to 7 with Comparative Examples 1 to 4, it is clear that the photopolymerizable composition of the present invention has high sensitivity to light in the visible region and is excellent in uniform film-forming ability. It is.

[0080]

As described above, the photopolymerizable composition of the present invention has a high photocurability to visible light, so that the range of choice of a light source for filtering is widened and a low energy exposure light source can be used. . Also, because of its high sensitivity, a large number of masters can be exposed within a given time. In addition, since the exposure source can be kept away from the original, the light source is parallelized. For example, when a halftone image is formed, various advantages such as a sharp halftone dot having a vertical side portion can be formed. Have. Furthermore, since it has excellent uniform film-forming ability and has good productivity when providing a layer of a photosensitive resin composition on a substrate, it greatly contributes to the industry.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location G03F 7/028 G03F 7/028

Claims (8)

[Claims] (A) at least one ethylenically unsaturated compound
A compound; (b) a titanocene compound; and (c) the following general
Containing a rhodamine dye represented by the formula (I):
Characteristic photopolymerizable composition. Embedded image(Where R¹~ R⁷Are each independently a hydrogen atom,
Kill, alkenyl, alkynyl, aryl,
A represents an ano group or a halogen atom, and A represents BF_Four ^-, Cl
O_Four ^-, PF₆ ^-Is shown. ) 2. The photopolymerizable composition according to claim 1, further comprising a glycine derivative. 3. The photopolymerizable composition according to claim 1, wherein the content of the titanocene compound is 0.01 to 50 parts by weight based on 100 parts by weight of the ethylenically unsaturated compound. 4. The photopolymerizable composition according to claim 1, wherein the content of the rhodamine dye is 0.01 to 50 parts by weight based on 100 parts by weight of the ethylenically unsaturated compound. 5. The photopolymerizable composition according to claim 2, wherein the content of the glycine derivative is 0.01 to 20 parts by weight based on 100 parts by weight of the ethylenically unsaturated compound. 6. A photosensitive original plate comprising a substrate and a photosensitive layer containing the photopolymerizable composition according to claim 1 formed thereon. 7. The photosensitive original plate according to claim 6, further comprising an oxygen-blocking protective layer formed on the photosensitive layer. 8. An exposure method comprising exposing the photosensitive master according to claim 6 or 7 using an argon ion laser, a FD-YAG laser or a helium-neon laser.