JPH03116149A - Photosensitve composition and printing plate material using the same - Google Patents

Abstract

PURPOSE:To enable a resin letterpress printing plate having flexibility, impact resistance, and elasticity, and capable of obtaining high-grade print quality by using as a base polymer a copolymer comprising polyvinyl alcohol type macromonomer units and polyalkyleneglycol macromonomer units. CONSTITUTION:The copolymer A to be used as the base polymer comprises the polyvinyl alcohol type macromonomer units and polyalkylene glycol macromonomer units, and radically polymerizable ethylenic monomer B and a photopolymerization initiator C are incorporated in the copolymer A. Especially, elasticity can be sufficiently controlled by selecting the composition of the copolymer, the polymerization degree and its distribution of each macromonomer, thus permitting the obtained photosensitive composition to form the resin printing plate having impact resistance, flexibility, and elasticity, and capable of giving high-grade print quality.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Product 1 The present invention relates to a photosensitive composition and a printing plate material using the same.

B, '1fsI&m A composition containing a polyvinyl alcohol-based polymer, a radically polymerizable ethylenic monomer (hereinafter referred to as a polymerizable monomer), and a photopolymerization initiator is called a photosensitive composition, and is used, for example, as a printing relief material. Widely used.

The above-mentioned photosensitive composition is prepared in the form of a sheet on a support such as a metal plate or a film plate (this is called a photosensitive resin plate), and then exposed and developed to become a resin letterpress. Photosensitive compositions using this method are widely used in the printing field because the uncured portions can be easily eluted with water after exposure and plate-making operations are easy.

As mentioned above, photosensitive compositions using polyvinyl alcohol-based polymers have many characteristics, and in particular, have high surface hardness for resin relief printing, so they are used in large quantities as materials for pattern plates. However, resin plates made of polyvinyl alcohol-based polymers generally have poor flexibility and impact resistance, so they often cause problems such as the resin plate being splashed during printing, especially in the winter when the temperature and humidity are low. This has become a problem. Furthermore, due to major changes in the environment surrounding printing technology in recent years, high quality printing is required even for polyvinyl alcohol resin plates. Under these circumstances, attempts are being made to improve and upgrade polyvinyl alcohol resin plates using both the base polymer, the polyvinyl alcohol polymer, and the polymerizable monomers to be blended. According to JP-A No. 60-57057, polyvinyl alcohol containing oxyethylene units is used as a base polymer, and JP-A No. 82-12144
According to Publication No. 5, a flexible resin plate can be obtained by using a polyvinyl alcohol polymer containing polyether units, but it is difficult to impart elasticity to the resin plate, which is required for high printing quality. There is no disclosure.

Problems to be Solved by C Ming The present invention aims to provide a polyvinyl alcohol-based resin letterpress printing plate that is flexible, impact resistant, and elastic and provides high quality printing.

As a result of intensive study on the above-mentioned problem, the inventors of the present invention developed a copolymer consisting of polyvinyl alcohol macromonomer units and polyalkylene glycol macromonomer units (
The present invention was completed by discovering that the object can be achieved by employing A) as a base polymer.

The present invention will be explained in detail below.

The present invention is a copolymer (A) consisting of a polyvinyl alcohol-based macro-septamer unit and a polyalkylene glycol unit.
The present invention relates to a photosensitive composition containing a radically polymerizable ethylenic monomer (B) and a photopolymerization initiator (C).

The polymer composed of polyvinyl alcohol macromonomer units (a) and polyalkylene glycol macromonomer units (b) used in the present invention is as follows. In other words, polyvinyl alcohol macromonomer units (
As long as a) has a polyvinyl alcohol polymer with a vinyl alcohol content of 50 mol% or more and a number average degree of polymerization of 3 to 500, the main chain portion connecting the macromonomer units does not need to have a specific structure. For example, those having a methacrylic acid ester structure are exemplified. Unit (a)
Examples include macromonomer units represented by the following general formula (a-1) that exhibit good copolymerizability during production and have relatively low hydrophobic properties.

Here, -R'-3- is a linking group between the methacrylic acid ester part and the polyvinyl alcohol polymer part, and R
1 is an alkylene group having 2 to 20 carbon atoms which may have a branch, and S is a sulfur atom. Specific examples of R1 include -(CHt)z--(cHt)*-(CHl),
--(CI(2),O--CH(C,H,)CH,--
CI((C,.l(,,)CI(wo-, etc.).

(PVA) is a monovalent polyvinyl alcohol polymer having a number average degree of polymerization of 3 to 500, preferably 5 to 300, and a vinyl alcohol content of 50 mol% or more.

The type and amount of units other than vinyl alcohol units constituting the monovalent polyvinyl alcohol polymer are not particularly limited as long as they are less than 50 mol%, and are selected from units that can be introduced, for example, by copolymerization or polymer reaction. Examples of such units include the following: That is, olefins such as ethylene, propylene, 1-butene, isobutyne,
Vinyl esters such as vinyl acetate, vinyl formate, vinyl propionate, vinyl butyrate, vinyl pivalate, vinyl persate, vinyl laurate, vinyl stearate, vinyl benzoate, acrylic acid or its salts, methyl acrylate, acrylic Acrylic acids such as ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, octadecyl acrylate, etc. Esters, methacrylic acid or its salts, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, methacrylic acid i
-propyl, n-butyl methacrylate, methacrylic acid i
-butyl, t-butyl methacrylate, 2- methacrylate
Methacrylic acid esters such as ethylhexyl, dodecyl methacrylate, and octadecyl methacrylate, acrylamide, N-methylacrylamide, N-ethylacrylamide, N,N-dimethylacrylamide, diacetone acrylamide, acrylamide propanesulfonic acid or its salt, acrylamide propyl dimethyl Amines or salts thereof and quaternary salts thereof, acrylamide derivatives such as N-methylolacrylamide or derivatives thereof, methacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, methacrylamidepropanesulfonic acid and its salts, methacrylamidepropyl dimethyl Amines or salts thereof and quaternary salts thereof, methacrylamide derivatives such as N-methylolacrylamide or derivatives thereof, methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether, i-butyl vinyl ether, - Vinyl ethers such as butyl vinyl ether, dodenruvinyl ether, stearyl vinyl ether, nitriles such as acrylonitrile, methacrylaterile, vinyl halides such as vinyl chloride, vinyliede chloride, vinyl fluoride, vinylidene fluoride, allyl acetate, allyl chloride, etc. maleic acid or its salts and its esters, itaconic acid or its salts and its esters, vinylsilyl compounds such as vinyltrimethoquinosilane, and isopropenyl acetate.

On the other hand, polyalkylene glycol macromonomer units (
For b), if the polymer has an oxyalkylene unit such as oxyethylene, oxypropylene, or oxytetramethylene and has a number average degree of polymerization of 1 to 300, the main chain portion connecting the macromonomer units is It does not need to have a specific structure, and examples include a methacrylic acid ester structure and an allyl ether structure. As an example of unit (b), considering copolymerizability during production, etc., the following general formula (b)
Examples include those having the structure represented by l).

Here, R'' represents a hydrogen atom or a lower alkyl group having 1 to 4 carbon atoms, and PAG is a monovalent homopolymer or monovalent copolymer of oxyalkylene units such as oxoethylene, oxypropylene, and oxytetramethylene. represents the union,
The number average degree of polymerization is from 1 to 300, preferably from 2 to 200.

Unit (a) constituting the copolymer (A) used in the present invention
The weight composition of and (b) is determined from the properties of the intended photosensitive resin plate. From the viewpoint of imparting impact resistance and flexibility, (b) is preferably 10 vt% or more, and -
From the viewpoint of shape retention of the photosensitive resin plate, (a) is 10ψt
% or more. Therefore, usually, the weight ratio of (a) and (b) in the copolymer (A) is (a)
/ (b) = 10/90 to 90/IOte is preferable. Furthermore, considering the provision of elasticity, (a)/
(b)=10/90 to 50/50 is more preferable.

Copolymerization f consisting of units (a) and units (b) of the present invention
The molecular weight of t-(A), expressed as the intrinsic viscosity of the copolymer (A) measured in trimethylsulfoxide at 30°C, is usually between 0.1 and lOa'ρ/9. Further, the copolymer (A) may be used within a range that does not impair the spirit of the present invention, usually 20
Unit (a) and unit (() within the range not exceeding wt%
There is no problem in containing monomer units other than b),
Examples of such units include the following.

That is, olefins such as ethylene, propylene, l-butene, and isobutyne, methacrylic acid or its salts, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, propyl methacrylate, n-butyl methacrylate, and methacrylic acid. i-butyl, t-butyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, octadecyl methacrylate, 2-hydroxyethyl methacrylate, polyoxyalkylene monomethacrylate, phosphoric acid ester of polyoxyalkylene monomethacrylate, methacrylic acid 2- Dimethylaminoethyl or its salt, 2-diethylaminoethyl methacrylate or its salt, methacrylic acid esters such as 3-trimethinesilylpropyl methacrylate, styrene,
Styrenes such as p-methylstyrene, α-methylstyrene, chloromethylstyrene, p-styrenesulfonic acid and its salts, acrylamide, N-methylacrylamide, N-ethylacrylamide, N,N-dimethylacrylamide, diacetone acrylamide, Acrylamidopropanesulfonic acid or its salt, acrylamide propylzmethylamine or its salt and its quaternary salt,
Acrylamide derivatives such as N-methylolacrylamide or its derivatives, methacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, methacrylamidepropanesulfonic acid or its salt, methacrylamidepropyldimethylamine or its salt and its quaternary salt, Examples include methacrylamide derivatives such as N-methylolmethacrylamide or derivatives thereof, nitriles such as acrylonitrile and methacrylonitrile, and vinyl halides such as vinyl chloride, vinylidene chloride, vinyl fluoride, and vinylidene fluoride.

As the polymerizable monomer (B) used in the present invention, any monomer that can be radically polymerized with a photopolymerization initiator can be used, but the polyvinyl alcohol macromonomer (a) unit of the present invention and polyalkylene glycol can be used. Those having good compatibility with the copolymer (A) consisting of macromonomer (b) units and the photopolymerization initiator (C) are preferably used, and examples of such polymers include the following. In other words, alkylene glycols and polyalkylenes represented by ethylene glycol, noethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, polytetramethylene glycol, copolymers of ethylene glycol and propylene glycol, etc. Glycol monoacrylate, monoalkyl monoacrylate, noacrylate, monomethacrylate, monoalkyl monomethacrylate, dimethacrylate, N-2-oxydiethylacrylamide, N-2-oxymethacrylate Amide, N-
Methylol acrylamide, N-methylol methacrylamide, N-3-oxypropylacrylamide, N-
3-Oxydipropylmethacrylamide, N,N-bis(
2-Oxydiethyl)acrylamide, N,N-bis(2
-oxydiethyl) methacrylamide, N-p-oxyphenylacrylamide, l'J-p-oxyphenylacrylamide, acrylamide, methacrylamide, m
-xylylenebisacrylamide, m-quinrylenebismethacrylamide, p-quinolylenebisacrylamide, p-xylylenebismethacrylamide 10 m-phenylenebisacrylamide, m-phenylenebismethacrylamide, ethylenediaminebisacrylamide, ethylenediaminebismethacrylamide, These monomers include acrylamide derivatives such as hexamethylenebisacrylamide and hexamethylenebismethacrylamide, methacrylamide derivatives, and the like, and these monomers may be used alone or in combination.

The photoinitiator (C) used in the present invention is a copolymer (A) consisting of polyvinyl alcohol macromonomer (a) units and polyalkylene gellicol macromonomer (b) units, and a polymerizable monomer (B). Any substance may be used as long as it dissolves in the system, such as benzophenone, benzoin, p,
p-dimethylbenzoin, benzoin methyl ether,
benzoin isopropyl ether, anroine or nuclear substituted aromatic anroine or anroine alkyl ether, diacetyl, benzyl, ketocarbonyl compounds,
Examples include 1.1-azocyclohexanecarbonitrile, azonitrile, 9.10-anthraquinone, chloroanthraquinone, 1,4-naphthoquinone, and 9.1G-phenanthroquinone.

A photosensitive composition containing the copolymer (A) of the present invention, a polymerizable monomer (B), and a photopolymerization initiator (C) as photosensitive components comprises (A) component [per 00 parts by weight, (B) It is preferable to use 30 to 250 parts by weight of component and 001 to 15 parts by weight of component (C). Furthermore, (A), (B)
, (C), such as ordinary polyvinyl alcohol polymers and polyamide polymers, may be used within the scope of the invention. In addition, for the purpose of improving the storage stability of the photosensitive composition, it may contain a known thermal polymerization inhibitor or storage stabilizer, and if necessary, other additives such as colorants, pigments, plasticizers, etc. It may contain additives.

The photosensitive resin composition of the present invention usually contains water, alcohol,
It is used by being formed into a sorted shape on a support such as a metal plate, plastic plate, or glass plate by casting from other organic solvents, hot melt molding, or hot extrusion molding.

E Examples The present invention will be explained in more detail with reference examples and examples below, but the present invention is not limited by these in any way. In addition, "part" and "%" in reference examples and examples
represent "parts by weight" and "% by weight", respectively, unless otherwise specified.

Reference Example 1 2,400 parts of vinyl acetate monomer and 600 parts of methanol were charged into a reactor equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, and a thermometer, and degassed by bubbling nitrogen gas for 15 minutes. Separately, thiol initial addition solution prepared by dissolving 0.78 parts of 2-mercaptoethanol in 50 parts of methanol, 2
- A continuous addition solution of thiol prepared by adding methanol to 60 parts of mercaptoethanol to make a total volume of 100 parts by volume, and an initiator solution prepared by dissolving 1.81 parts of 2゜2゛-azobisisobutyronitrile in 50 parts of methanol, respectively. Adjust,
Nitrogen replacement was performed by bubbling nitrogen gas.

The temperature of the reactor was started to rise, and when the internal temperature reached 60° C., a separately prepared initial addition solution of thiol and an initiator solution were added in this order to start polymerization.

Immediately, continuous addition of the thiol solution was started to continue polymerization. Continuous addition of thiol was carried out with the aim of achieving the values shown in the table below in accordance with the increase in solid content concentration in the reactor as the polymerization progressed. The solid content concentration was checked by sampling.

Solid content (%) 10 20 30 4
0 50 continuous addition amount (parts by volume) 15.5 31.
3 47.2 63.1 79.0 Polymerization was carried out for 3 hours while continuously adding thiol, and the polymerization was stopped by cooling. The solid content concentration at this time was 51.0%, and the amount of the thiol solution continuously added was 82.0 parts by volume. Subsequently, unreacted vinyl acetate monomer was removed at 30° C. under reduced pressure while occasionally adding methanol to obtain a methanol solution of polyvinyl acetate. A portion of this methanol solution was poured into ether to recover polyvinyl acetate, purified by reprecipitation twice with acetone-ether, and then dried under reduced pressure at 40°C. This purified polyvinyl acetate was subjected to proton NMR (GX-500 manufactured by JEOL (Aji)) using CDCl3 as a solvent.
(the same applies hereafter), it was found to be a polyvinyl acetate having a number average degree of polymerization of 31 and a hydroxyl group at one end.

Reference Example 2 A methanol solution (a degree 48.596) 52.5 parts, 97.5 parts of methocinopolyethylene glycol methacrylate (Blenmar PME-200 manufactured by NOF Corporation), 74.5 parts of methanol and 0.0 parts of 2-mercaptoethanol.
5 parts were charged, and nitrogen substitution was performed by bubbling nitrogen gas at room temperature. Start heating up the reactor, and when the internal temperature reaches 60°C, 2.2 azobisisobutyronitrile and 0.1
Polymerization was started by adding an initiator solution in which 5 parts were dissolved in 20 parts of methanol and replaced with nitrogen, and the polymerization was continued with stirring for 20 hours. Subsequently, 75 parts of methanol was added, the temperature was adjusted to 40°C, and 35 parts of a 10 wt% sodium hydroxide methanol solution was added.
A polymer (copolymer 1) consisting of 22% by weight of polyvinyl alcohol macromonomer units and 78% by weight of polyethylene glycol macromonomer units was obtained. The live eye viscosity measured in dimethyl sulfoxide at 30°C was 2.03 dQht. Furthermore, copolymers 2 to 5 shown in Table 1 were obtained in the same manner.

CH.

Margin below 1) 2) Polyvinyl alcohol macromonomer unit Polyalkylene glycol macromonomer unit (b) -2: Methoxypolyethylene glycol methacrylate (Blenmar PME-200 manufactured by NOF (Aji)) (b) -3:
Methoxypolyethylene glycol methacrylate (Blenmar PME-400'1 (b) manufactured by NOF Corporation)
-4 Nimethoxypolyethylene glycol methacrylate (Blenmar PME-100 manufactured by NOF Corporation) (b
)-5: Methoxypolyethylene glycol methacrylate (Blenmar PE-400 manufactured by NOF Corporation) Example 1 Copolymer (A) consisting of polyvinyl alcohol macromonomer (a) units and polyalkylene glycol macromonomer (b) units 100 parts methacrylic acid 2-
Hydroxyethyl 90 parts diethylene glycol dimethacrylate ester
10 parts methylhydroquinone
0.05 parts benzoin isopropyl ether 3 parts water
200 parts of each of the above components (copolymer (A)
(using copolymer 2 obtained in Reference Example 2),
After uniformly dissolving the solution while stirring while heating at 90°C in a flask, the solution is defoamed and applied on an aluminum plate.
It was dried at 80° C. for 30 minutes to obtain a 0.5 mm thick photosensitive resin plate.

A negative was brought into close contact with this resin plate and irradiated with a mercury lamp having a wavelength of 320 to 400 mμ for 3 minutes, and the unexposed areas were washed with water at 25° C. for 5 minutes to observe halftone dot reproducibility. In addition, 32
A cured product was obtained by irradiating the entire surface with a mercury lamp having a wavelength of 0 to 400 mμ for 10 minutes, and the flexibility of the cured film at 5°C and 130% RH and the elasticity at 20°C were examined.

The results are shown in Table 2.

Examples 2 to 4 Tests were conducted in the same manner as in Example 1, except that copolymers 2 to 5 were used instead of copolymer 1 used as copolymer (A) in example 1. The results are shown in Table 2.

Comparative Example 1 Polyvinyl alcohol macromonomer (a) units and polyalkylene glycol monomer (b) were used as base polymers.
) unit instead of the polymer (A) consisting of PVA-20
Tests were conducted in the same manner as in Examples 1 to 5 above, except that Example 5 was used (degree of polymerization: 550, degree of saponification: 88 mol%). The results are shown in Table 2.

Table 2 (*1) ○: Items that do not break even when folded x Items that easily break when bent twice (+2) 20°C according to the method of JIS-6301
Measured value ○: Shows rebound resilience △: Shows small rebound resilience ×: Does not show rebound resilience A photosensitive composition is obtained that becomes a resin plate that provides a certain high quality of printing. This is an effect brought about by employing the polymer consisting of polyvinyl alcohol macromonomer units and polyalkylene glycol macromonomer units of the present invention as a base polymer. This was obtained by sufficiently controlling the degree of polymerization and the distribution of the degree of polymerization of both macromonomer units constituting the polymer, and it has extremely high industrial value.

Claims (2)

[Claims] (1) It is characterized by containing a copolymer (A) consisting of a polyvinyl alcohol macromonomer unit and a polyalkylene glycol macromonomer unit, a radically polymerizable ethylenic monomer (B), and a photopolymerization initiator (C). A photosensitive composition. (2) A printing plate material comprising the photosensitive composition according to claim 1.