JPS6053041B2 - Photosensitive resin composition with good storage stability - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photosensitive resin composition that has high storage stability and does not cause a decrease in sensitivity.

Conventionally, the main plates used for printing were letterpress and metal-corrosion letterpress, but these problems caused problems such as lead poisoning and lower back pain for workers due to transporting heavy objects, and water pollution caused by the etching solution used when working with metal-corrosion plates. As problems such as water pollution and inadequate workplace environments have become more apparent, printing using photosensitive resin as a plate material has become mainstream, as it has solved all of these problems.

This trend will continue, and it is expected that photosensitive resin plates will account for the majority of printing plates in the near future. A photosensitizer is added to all general photosensitive resin compositions.
This photosensitizer is contained in a photosensitive resin, and when it is irradiated with active light including ultraviolet rays, it is excited to a singlet state and changes to a triplet state, and then transfers energy to the photosensitive resin and undergoes a photocuring reaction. The photosensitive resin is rendered insolubilized in the solvent by either inducing or decomposing itself into radicals using actinic rays to radicalize the polymer or the photopolymerizable unsaturated monomer described below. It plays a leading role. Therefore, a fundamental question is raised here. That is, as mentioned above, since the photosensitive resin composition contains a photosensitizer, under active light that excites it, a photocuring reaction gradually occurs even if the illuminance of the active light is small, and the liquid photosensitive resin In this case, the viscosity of the composition increases, which leads to the disadvantage that not only is it difficult to defoam, but also the plate thickness cannot be kept constant. Alternatively, gel components may be generated in some areas, resulting in not only poor developability but also a decrease in resolution. In addition, if the photopolymerizable unsaturated monomer contained in the photosensitive resin is heated or stored for a long period of time, it will quickly polymerize once the added thermal polymerization inhibitor is consumed. The polymerization progresses so quickly that the viscosity increases initially and eventually becomes solid.

Therefore, even if a photosensitive resin composition is stored in a place where it is not irradiated with actinic rays, the phenomenon of thickening or solidification is observed. In such a case, not only the quality deteriorates significantly but also the product loses its value as a product. It takes a considerable amount of time for a photosensitive resin composition or a photosensitive resin master plate to be produced by a manufacturer and delivered to each user, and for flea users, a certain amount is secured to make printing plates. However, it may take a long time before it is used up, and the quality must not change during this time. Additionally, while it is desirable for photosensitive resins to be kept in a cool, dark environment during shipping and storage, it is desirable for photosensitive resins to maintain constant quality even under conditions such as rising temperatures and changing humidity. It is possible. Solid photosensitive resin master plates are supplied with a photosensitive resin layer of a certain thickness coated on aluminum, iron, or zinc plates in advance, so they do not exhibit as much state change as liquid photosensitive resins. However, if the storage stability is poor, there will be some residual development on the shoulder area even if the development process is done quite vigorously, which may cause thick characters when printed using this plate, or prints that are not sharply cut. I have no choice but to do so.

If the three-dimensional crosslinking reaction during storage progresses further, even if you try to develop it after applying a negative film and exposing it to light, it will not be able to be developed at all and will no longer be commercially available. Normally, photosensitive resins contain common radical inhibitors such as benzoquinone, p-torquinone, and p-
Quinone compounds such as xylo φ quinone, hydroquinone, p-
Hydroxy aromatic compounds such as methoxyphenol and p-Tel-butylcatechol, and amines such as phenyl-α-naphthylamine and N,N5-diphenyl-p-phenylenediamine are added.

However, it was confirmed that these compounds do not have sufficient storage stabilization ability for long-term storage of photosensitive resins. In addition, radicals are generated by irradiation with actinic rays, which induces polymerization and crosslinking reactions, but in the process of curing the photosensitive resin due to light irradiation, the chemicals added as stabilizers generate radicals. A photosensitive resin containing a stabilizer that captures the photopolymerization reaction and has stain-cleaning properties will be severely colored, and the curing speed upon irradiation with light may be completely reduced. As a result of intensive research on these points, the present invention has been achieved.

That is, the present invention comprises a polymer (4) soluble in an aqueous solvent, a photopolymerizable unsaturated monomer (B), a photomultiplier (0) and a stabilizer (2).
), the stabilizer (2) has the general formula (R1 is hydrogen or an alkyl group having 1 to 4 carbon atoms,
R2 represents an alkyl group having 1 to 4 carbon atoms or a phenyl group, or an alkylene group having 4 to 6 carbon atoms, which together form a ring with R1 and R2.

) (R3 and R4 represent an alkyl group having 1 to 4 carbon atoms.

) (R5, R6, R7, R8 represent an alkyl group having 1 to 4 carbon atoms or a phenyl group.) From the group consisting of (1) oximes, (■) hydroxylamines, and (■) thiurams. at least one compound selected; wherein the stabilizer is 0.001 to
This is a photosensitive resin composition characterized in that the amount of the compound is 5% by weight.

The polymer (4) used in the present invention may be any polymer as long as it is soluble in water or a dilute alkali aqueous solution.
, maleic anhydride adduct of 2-polybutadiene, and ring-opening polymerization of this adduct with sodium hydroxide, potassium hydroxide, lithium hydroxide, etc. Body (JP-A-51-104903
), a conjugated diolefinic hydrocarbon (E) and an α,β monoethylenically unsaturated carboxylic acid (F) are essential, and a monoolefinically unsaturated compound (G) is added thereto in an amount of E: 10 to 1 mol %, A copolymer containing F: 2 to 90 mol% and G: O to 85 mol%, or a part of the α,β monoethylenically unsaturated carboxylic acid in the copolymer is an alkali metal salt or an ammonium salt. or a copolymer which is an amine salt (patent application No. 51-509)
59, Japanese Patent Application No. 51-85186), etc. are preferably used.

The above conjugated diolefin hydrocarbon (E) is preferably 1,3-butadiene, isoprene, chloroprene, dimethylbutadiene, etc., and α,β monoethylenically unsaturated carboxylic acid (
F) includes monocarboxylic acids such as acrylic acid and methacrylic acid, dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid, acid anhydrides such as maleic anhydride and itaconic anhydride, monoethyl maleate, monobutyl maleate, and fumaric acid. Monoesters of dicarboxylic acids such as monoethyl acid, monobutyl fumarate, monoethyl itaconate, and monobutyl itaconate are suitable, and as the monoolefinically unsaturated compound (G), styrene, α-methylstyrene, acrylonitrile, and methacrylonitrile are preferred. , acrylamide,
Methacrylamide, general formula (wherein R is hydrogen or a methyl group, Rl.

represents an alkyl group having 1 to 18 carbon atoms. ), benzyl acrylate, glycidyl acrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate or their methacrylates, dimethyl maleate, dioctyl maleate, dimethyl itaconate, dioctyl itaconate, etc. Diesters of monoethylenically unsaturated carboxylic acids, esters of hydroxyalkyl alcohols such as 2-hydroxyethyl acrylate or methacrylate, general formula (where Rll and Rl2 are hydrogen or methyl groups, and Rl3 is an alkyl group having 1 to 12 carbon atoms) The group n represents an integer from 1 to 23.

), alkoxyalkyl acrylate or methacrylate, alkoxypolyalkylene glycol acrylate or methacrylate, etc. can be preferably mentioned.

As the photopolymerizable unsaturated monomer (B), in addition to the above-mentioned monoolefinic unsaturated compound (G), N,N''-methylenebisacrylamide or methacrylamide, ethylene glycol diacrylate or dimethacrylate, polyalkylene can be used. Glycol (alkylene glycol unit 2
Di-, tri-, tetra-acrylates or di-, tri-acrylates of polyhydric alcohols such as diacrylates or dimethacrylates (~23), glycerin, pentaerythritol, trimethylolalkanes, tetramethylolalkanes (alkanes include ethane and puwapan). , tetra-acrylates, 2,2-bis(4-methacryloxydiethoxyphenyl)propane, 2,2-bis(4-acryloxydiethoxyphenyl)propane, 2,2-
Bis(4-acryloxypropyloxyphenyl)propane, ``diarylidenepentaerythritol, Aronix type monomer M-5500, M manufactured by Toagosei Chemical Industry Co., Ltd.
-5700, M-6100, M-6300, M-803
0,M-806 maki can be exemplified.

These photopolymerizable unsaturated monomers are used in an amount of 5 to 20% by filtration based on the polymer (4), preferably 10 to 1%.
It is used within the range of 0%.

Two or more types can be used in combination within this range. If it is less than 5% by weight, the curing speed when the photosensitive resin layer is irradiated with light is slow, the plate making time becomes long, and a sufficient degree of curing cannot be expected, resulting in a decrease in the mechanical strength of the printing plate.

If it exceeds 200% by weight, the amount of photopolymerizable monomer in the photosensitive resin is too large, resulting in large volumetric shrinkage after photopolymerization, resulting in the drawback that the printing plate does not faithfully reproduce a negative film.

Examples of the photosensitizer (6) used in the present invention include α-diketones, such as diacetyl and benzyl, which are usually used as photoreaction initiators, acyloins such as benzoin and pivaloin, benzoin methyl ether, benzoin ethyl ether, and benzoin. Examples include acyloin ethers such as isopropyl ether, and polynuclear quinones such as anthraquinone and 1,4-naphthoquinone. The amount of photosensitizer added is 0.1 to 10% by weight, preferably 1 to 5% by weight, based on the polymer (4). If it is less than 0.1% by weight, the photocuring rate cannot be achieved to a sufficient value, and not only the exposure time must be increased, but also the crosslinking density becomes low, resulting in a decrease in the mechanical strength of the printing plate.

If the filtration amount exceeds 1%, not only is it uneconomical because all the added photosensitizers do not contribute to the photocuring reaction, but also the unreacted photosensitizers are extracted by the ink vehicle during printing, causing damage to the printing plate. This will have a negative effect on mechanical strength. The stabilizer (2) used in the present invention has the general formula (1) (R1 is hydrogen or an alkyl group having 1 to 4 carbon atoms, R2 is an alkyl group having 1 to 4 carbon atoms or a phenyl group, or R
1 and R2 represent an alkylene group having 4 to 6 carbon atoms and forming a ring.

) Exemplary oximes include acetaldoxime, propionaldoxime, n-butyraldoxime, IsO-butyraldoxime, acetoxime, methyl ethyl ketoxime, diethyl ketoxime, methylpropyl ketoxime, and cyclopentanone oxime. ,
Examples include cyclohexanone oxime, cycloheptanone oxime, etc., and the general formula (■) (R3, R, has 1 to 1 carbon atoms)
4 represents an alkyl group.

), for example, -N
, N-dimethylhydroxylamine, N,N-diethylhydroxylamine, N,N-dibutylhydroxylamine, N,N-methylethylhydroxylamine, etc., and the general formula (■) (R5,R4,,R,, R8 represents an alkyl group having 1 to 4 carbon atoms or a phenyl group.

Examples of thiurams shown in ) include tetramethylthiuram disulfide, tetraethylthiuramnodisulfide, tetra n-butylthiuram disulfide,
"-dimethyl-N,N"-diphenylthiuram disulfide and the like.

The amount of these stabilizers added is from 0.001 to Polymer A.
5% by weight, preferably 0.01-2% by weight. Within this range, several types of homologous compounds may be mixed, or several types of stabilizers (1) to (■) may be mixed.

If the amount of the stabilizer added is less than 0.001% by weight, it will not be possible to provide a sufficient storage stabilizing effect to the photosensitive resin, and if it exceeds 5% by weight, the stabilizer will not be sufficiently dissolved in the photosensitive resin layer. This not only reduces the sensitivity but also reduces the mechanical strength of the printing plate. Among the commercially available photopolymerizable unsaturated monomers mentioned above, p-methoxyphenol and the like are usually used. Although a small amount of thermal polymerization inhibitor is added, in order to use it in the present invention, this small amount of thermal polymerization inhibitor has no effect on storage stability, sensitivity, etc. The liquid photosensitive resin according to the present invention can be used as it is without removing it from the photopolymerizable unsaturated monomer. After adding the polymer, photosensitizer, and stabilizer and thoroughly mixing them, the solvent used during polymerization is removed, or the photopolymerizable unsaturated monomer, Solid photosensitive resins are produced by uniformly mixing photosensitizers and stabilizers, while solid photosensitive resins are produced by adding each reagent to a polymer solution to make a homogeneous solution, and then casting it onto a support or adding it to the polymer solution. It is usually manufactured by heating and depressurizing a homogeneous solution to remove the solvent, and then heating and press-molding the photosensitive resin composition in the form of a gram or flake onto a support via a spacer of a certain thickness. be.

As mentioned above, when storing a liquid photosensitive resin, if the storage stability is good, the viscosity of the composition will not change and no gel will occur, but if the storage stability is poor, the viscosity will change significantly. A gel is generated partially, and when stored further, the entire product finally solidifies.

Therefore, to investigate storage stability. First, the viscosity of the liquid photosensitive resin was measured immediately after production and after storage for a certain period of time using a B-type rotational viscometer at 30°C, and the degree of increase in viscosity was determined according to the formula below, which was used as a guideline for storage stability. did. Viscosity increase rate = ■ However, V1 = viscosity of liquid photosensitive resin immediately after production
Degree V2=-liquid photosensitivity after storage for a period of time
Indicates the viscosity of the resin.

In the case of a solid photosensitive resin, the photosensitive resin original plate was stored for a certain period of time immediately after production, and then dissolved in a solvent, and the weight % of the insoluble portion was used as a measure of storage stability.

The photosensitive resin material of the present invention not only has excellent storage stability, but also has no decrease in sensitivity, so it is possible to provide an excellent photosensitive material for printing whose quality remains constant over a long period of time. Furthermore, the photosensitive resin composition of the present invention can not only provide a photosensitive material for printing, but also be widely used as a photosensitive material for name plates, printed wiring, displays, and photoadhesives. EXAMPLES Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples as long as the gist thereof is not exceeded.

Example 1 Butadiene/ethyl methacrylate/acrylic acid obtained by radical polymerization using methanol as a solvent and 2,7-azobisisobutyronitrile as an initiator = 55/25
/20 (molar ratio) copolymer solution 136y of 5% by weight was placed in a Mitsuro separable flask, and photopolymerization consisting of tetradecaethylene glycol dimethacrylate/2-ethoxyethyl methacrylate 3/1 (weight ratio) was carried out. 65y of sexually unsaturated monomer was added, 1.2f of photosensitizer benzoin isopropyl ether, 0.8f of stabilizer N,N-diethylhydroxylamine were added, and after stirring well, methanol was distilled off under reduced pressure. A liquid photosensitive resin composition was prepared.

The viscosity of the composition was measured at 30°C and was 15,000.
It was CpS.

Further, about 9f of the composition was placed on a 100μ thick, 8×80 polyester film, and 1.5? A polyester film of the same size was placed on the composition via a thick spacer, and a 5 m thick glass plate was used to press the film and the top surface of the glass plate was marked 0.
Ultraviolet light from a 250W ultra-high pressure mercury lamp was irradiated for 5 seconds from a distance of . When the glass plate was removed and the upper and lower polyester films were peeled off, the photocured layer remained on the upper polyester film. After thoroughly washing with 0.5% sodium hydroxide aqueous solution, washing with water, and heating and drying, the thickness of the cured layer was measured to be 250.
It was μ.

Therefore, the photocuring speed was 50 μSec. This composition 80f was placed in a transparent glass sample pin with a capacity of 100 ml, and the pin was immersed in a constant temperature bath controlled at 30 C under a fluorescent lamp that cut off active rays of 500 ml or less. When the viscosity was measured after storage for 6 months, it was 3
The viscosity increased slightly to 37,500 CPS at 0'C, and the viscosity increase rate was 1.5, but no gel was formed.

Further, when the photocuring speed was measured, a value of 50 μ/Sec was obtained, indicating that the sensitivity did not decrease after storage.

Approximately 5 g of the composition stored for 6 months was placed in a 100μ thick, 8×8
C! n polyester film and around this polyester film support to a thickness of 0.87! I placed a Rit spacer. On the other hand, place a negative filler on a glass plate that has been devised to reduce the pressure, and while reducing the pressure,
The glass plate was covered with a crystalline 1,2-polybutadiene film of .mu. to completely adhere the negative film to the glass plate. The negative film side was pressed onto the composition, and actinic light from a 250 W ultra-high pressure mercury lamp was irradiated for 1 minute from a distance of 60 d from the upper surface of the glass plate. Spray developed with dilute alkaline water, washed with water, 8C
The printing plate obtained by heating and drying at fC for 5 minutes was faithful to the original image. When printing with letterpress ink and ink using the printing plate obtained here, printed matter with good ink transfer properties was obtained. Comparative Example 1 A photosensitive resin composition was prepared in the same manner as in Example 1, except that p-methoxyphenol, which is commonly used as a radical polymerization inhibitor, was used in place of the N,N-diethylhydroxylamine stabilizer.

The viscosity of the composition immediately after preparation was 18,00 μPs at 30° C., and the photocuring rate was 50 μ/Sec, which was the same as that of the composition of Example 1. However, when stored for 6 months, the viscosity of the composition became 800,000 Cps and the viscosity increase was 43.4.
It became almost solid. Because the viscosity was too high, it was difficult to make a plate. Examples 2 to 8 Photosensitive resin compositions were prepared in the same manner as in Example 1 except that N,N-diethylhydroxylamine was replaced with the stabilizer shown in Table 1, and the viscosity increase rate and photocuring before and after storage were determined. The speed was measured and the results shown in Table 1 were obtained.

In either case, no gel was formed and the storage stability was excellent.
When printing plates were prepared from each composition in Table 1 in the same manner as in Example 1, plates faithful to the original images were obtained. Very good prints were obtained from these printing plates. Examples 9 to 12 Photosensitive resin compositions were prepared in the same manner as in Example 1, except that the photopolymerizable unsaturated monomers in Example 1 were changed to those in Table 2, and the viscosity increase and photocuring were determined. The speed was measured and the results in Table 2 were obtained.

When printing plates were prepared from each of the photosensitive resin compositions shown in Table 2 after storage, very good printing plates were prepared, and printing with these printing plates was also good.

Example 13 83 g of a 60 wt % solution of butadiene/methyl methacrylate/methacrylic acid = 50/30/20 (molar ratio) copolymer polymerized using methanol as a solvent and 2,2″-azobisisobutyronitrile as a catalyst. into a 300m1 Mitsuro separable flask, and add 3 liters of lithium hydroxide.
．． 30 Da of water containing 2F was added and thoroughly stirred to neutralize 100% of the carboxyl groups in the polymer.

2,7-bis(4-methacryloxydiethoxyphenyl)propane 25y1 benzoin isopropyl ether 1y. 0.5y of sN,N-diethylhydroxylamine was added and stirred until a homogeneous solution was obtained. Methanol and water were removed under reduced pressure while heating to obtain a solid photosensitive resin composition. 8×8
Approximately 3y of the composition was placed on a grained aluminum plate with a thickness of 0.37m, and heated at 100°C for 10
A solid photosensitive resin original plate was prepared by press molding for 3@ under the condition of 0k9/Clt.

The resin layer of this original plate was peeled off, and 2f of it was cut into small pieces.
Pour into a 5m1 Erlenmeyer flask and add methanol/
18 f of a mixed solvent of water = 1/1 (weight ratio) was added, shaken well, and left at room temperature for 24 hours.

The solid content in the mouth liquid was measured by passing the entire amount through a millipore filter with a pore size of 1 μm, and it was found to be 1% by weight, indicating that there was no gel content. This original plate was placed in a glass container, the atmosphere was controlled at 30° C., it was placed under a fluorescent lamp that cut off active rays of 500 rpm or less, and stored for 6 months. When the gel content in the resin layer was determined by the above procedure, it was found to be zero. In addition, when a negative film was closely attached to the original plate after storage, light from a 250 W ultra-high pressure mercury lamp was irradiated for 1 minute from a distance of 60 d from the top surface, and the plate was developed by spraying with warm water at 40°C, a printing plate faithful to the original image was obtained. . Prints from this printing plate were also good. Comparative Example 2 Instead of N,N-diethylhydroxylamine stabilizer, p
A solid liquid photosensitive resin original plate was prepared in the same manner as in Example 13 except that -methoxyphenol was used.

Claims (1)

[Claims] 1. A photosensitive resin composition comprising a polymer (A) soluble in an aqueous solvent, a photopolymerizable unsaturated monomer (B), a photosensitizer (C), and a stabilizer (D). In the product, the stabilizer (D) has the general formula (
I) ▲Mathematical formulas, chemical formulas, tables, etc.▼(R_1 is hydrogen or an alkyl group with 1 to 4 carbon atoms, R_2 is a carbon number 1
~4 alkyl group or phenyl group, or R_1 and R
Represents an alkylene group having 4 to 6 carbon atoms that forms a ring with _2. ) (II) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (R_3,
R_4 represents an alkyl group having 1 to 4 carbon atoms. ) (III) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (R_5
, R_6, R_7, and R_8 represent an alkyl group having 1 to 4 carbon atoms or a phenyl group. ) at least one compound selected from the group consisting of (I) oximes, (II) hydroxylamines, and (III) thiurams, wherein the stabilizer is polymer A.
1. A photosensitive resin composition, characterized in that the content thereof is 0.001 to 5% by weight.