JP2967791B2 - Negative photosensitive resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel negative photosensitive resin composition, and more particularly, to a relief printing plate which can use water as a developer and has excellent resistance to aqueous inks. The present invention relates to a negative photosensitive resin composition which can provide

[0002]

2. Description of the Related Art Conventionally, oil-based inks have been used in letterpress printing plates. However, such oil-based inks cause mist to have an adverse effect on the human body, and printed matter using the ink requires a long time for drying. Water-based inks have recently attracted attention because they have drawbacks such as stains on hands, and therefore, the emergence of a negative-type photosensitive resin composition suitable for water-based inks instead of the oil-based inks has been particularly desired. I have.

On the other hand, conventionally known negative photosensitive resin compositions are developed using an organic solvent such as an alcohol or a halogen as a developing solution (for example, US Pat. No. 3,024). , No. 180, Japanese Patent Publication No. 51
No. 43374, U.S. Pat. No. 3,801,328, etc., and alkaline water developing type and water developing type (for example, JP-B-54-3790, JP-B-53-208).
No. 2 gazette, etc.)
Use of a water-developable negative photosensitive resin composition is strongly desired from the viewpoint of preventing mistakes in the preparation of a developing solution.

[0004] However, the conventional water-developing type has a problem that it cannot be printed using water-based ink due to poor water resistance. Therefore, in order to solve such a problem, various negative-type photosensitive resin compositions have been proposed so far (JP-A-61-22339, JP-A-61-246742, JP-A-61-246742). -3068636
JP, JP-A-2-4255).

However, these compositions have water developability and can be printed with water-based inks. However, since these compositions are not completely water-developable, the developer must be turbid or a surfactant must be added. In addition, the resulting printing plate has drawbacks such as insufficient water resistance of the relief portion and poor printing durability.

Further, polyvinyl alcohol or a vinyl alcohol copolymer is converted to N-methylolacrylamide or N-methylolacrylamide.
Water-developable negative-type photosensitive resin composition having an unsaturated polyvinyl alcohol obtained by reacting 1-40 mol% of hydroxyl groups with acrylamide methyl ether or methacrylamide methyl ether by reacting with methylol methacrylamide; Has been disclosed (JP-B-49-5923).
No.). However, this composition has disadvantages such as low sensitivity and insufficient water resistance of the cured product.

As described above, in the conventional negative photosensitive resin compositions, the resulting printing plates are inferior in water resistance, poor in printability with water-based inks, and not completely water-developable. The improvement has been strongly desired.

[0008]

SUMMARY OF THE INVENTION In accordance with the present invention, a water-developable negative photosensitive resin composition capable of providing a relief printing plate having good water resistance and excellent printability for water-based inks in response to such a demand. It was made for the purpose of providing goods.

[0009]

Means for Solving the Problems The present inventors have conducted intensive studies to develop a negative photosensitive resin composition having the above-mentioned preferable properties, and as a result, a specific vinyl alcohol polymer, a urea derivative, By a resin composition containing an unsaturated acrylic urethane oligomer and a photopolymerization initiator,
The inventors have found that the object can be achieved, and have completed the present invention based on this finding.

That is, the present invention relates to (A) a vinyl alcohol polymer etherified with lower alkylol acrylamide or lower alkylol methacrylamide having an average degree of polymerization of 200 to 2,000, (B) urea, thiourea, Lower alkylated, lower alkylolated or lower alkyl lower alkylolated derivative and lower alkylol acrylamide or lower alkylol methacrylamide condensate, (C) having acrylic or methacrylic group at both ends via urethane bond An object of the present invention is to provide a negative photosensitive resin composition containing a polyester oligomer and (D) a photopolymerization initiator.

In the composition of the present invention, a vinyl alcohol polymer etherified with lower alkylol acrylamide or lower alkylol methacrylamide is used as the component (A). Examples of the lower alkylol of the lower alkylol acrylamide or the lower alkylol methacrylamide in the vinyl alcohol polymer include methylol, ethylol, propylol, and butyrol. The vinyl alcohol polymer may be polyvinyl alcohol obtained by completely saponifying polyvinyl acetate, or may be a partially saponified product, that is, a vinyl alcohol copolymer having a vinyl alcohol unit. When a copolymer is used, a copolymer containing at least 60 mol% of a vinyl alcohol unit is desirable. Examples of the copolymer component of the copolymer include vinyl acetate, acrylic acid, methacrylic acid, acrylamide, methacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, styrene, ethylene, propylene, maleic anhydride, acrylonitrile, methacrylic acid. Ronitrile, acrylates, methacrylates and the like can be mentioned.

The degree of polymerization of the vinyl alcohol polymer is not particularly limited as long as the polymer is water-soluble, but the average degree of polymerization is from 200 to 2,000, preferably 30.
The thing of 0-1000 is suitable.

The etherified vinyl alcohol-based polymer used as the component (A) in the present invention can be prepared by adding the vinyl alcohol-based polymer in the presence of an acidic catalyst such as an inorganic acid, a sulfonic acid derivative, and an ammonium halide. With lower alkylol acrylamide or lower alkylol methacrylamide.

The etherified vinyl alcohol polymer thus obtained preferably contains at least 50 mol% of a vinyl alcohol unit, and the photosensitive resin composition obtained by using this polymer has a sufficient sensitivity. And a printing plate having satisfactory flexibility, water resistance and printability.

In the composition of the present invention, urea, thiourea or a lower alkylated, lower alkylolated or lower alkyl lower alkylolated derivative thereof and a lower alkylol acrylamide or a lower alkylol methacrylamide are used as the component (B). Is used.

Examples of the condensate include polycondensation of an alkylol derivative or an alkylated alkylol derivative of urea or thiourea with N-alkylolacrylamide or N-alkylolmethacrylamide in the presence of an acid or ammonium salt. Or reacting urea or thiourea with formaldehyde to form a linear condensation polymer, which is then grafted with N-alkylolacrylamide or N-alkylolmethacrylamide in the presence of an acid or ammonium salt. Reaction product (Japanese Patent Publication No. 54-3790) or urea, thiourea or their alkyl derivatives and N-alkylolacrylamide or N-alkylolmethacrylamide in an acid in water or a hydrophilic organic solvent. Or use an alkali catalyst to inhibit thermal polymerization Under the presence, and the like those obtained by reacting under stirring for 1 to 5 hours at a temperature range of 60 to 95 ° C. (KOKOKU 1-48528 Patent Publication). Here, as the lower alkyl in the lower alkylated, lower alkylolated or lower alkyl lower alkylolated derivative, methyl, ethyl, propyl, butyl, etc., and as the lower alkylol, methylol, ethylol, propylol, butyrol, etc. Examples of the lower alkylol of lower alkylol acrylamide or lower alkylol methacrylamide include methylol, ethylol, propylol, and butyrol.

In the composition of the present invention, as the component (C), a polyester oligomer having an acrylic group or a methacryl group at both ends via a urethane bond is used. It is desirable that this is compatible with the components (A) and (B). Such materials include, for example, diethylene glycol, 1,6-hexanediol, 1,
A diol compound such as 3-dimethylol-2-propionic acid is reacted with a dicarboxylic acid such as adipic acid to form a polyester oligomer first, and then the two hydroxyl groups at the ends of the polyester oligomer are subjected to xylylenediamine. Unsaturated acrylic urethane oligomers obtained by reacting a diisocyanate compound such as isocyanate and then reacting 2-hydroxyethyl methacrylate with the isocyanate group at the end of the reaction product can be exemplified.

In the composition of the present invention, the photopolymerization initiator used as the component (D) is not particularly limited, and may be selected from those conventionally used in photopolymerizable resin compositions.
Any one can be selected and used. Examples of the photopolymerization initiator include benzophenone derivatives such as benzophenone, 2,4-dihydroxybenzophenone and 2-hydroxy-4-alkoxybenzophenone; benzoin derivatives such as benzoin, benzoin isopropyl ether and benzoin methyl ether; anthraquinone; Examples include anthraquinone derivatives such as anthraquinone and 2-ethylanthraquinone. One of these photopolymerization initiators may be used,
A combination of more than one species may be used.

Regarding the mixing ratio of each component in the composition of the present invention, 10 to 200 parts by weight of the component (B), 5 to 200 parts by weight of the component (C), and (D) )) It is preferable to mix the components in a ratio of 0.1 to 10 parts by weight. If the amount of the component (B) is less than 10 parts by weight, the sensitivity is low, the exposure time is long, and the mechanical strength and water resistance of the printing plate obtained due to the low crosslinking density are insufficient. When the amount exceeds the weight part, the surface of the photosensitive resin layer becomes sticky and the adhesion to the negative film is deteriorated, so that the reproducibility of the obtained relief tends to decrease.

If the amount of the component (C) is less than 5 parts by weight, the flexibility is poor, and the plate may be chipped during printing. If the amount exceeds 200 parts by weight, the compatibility with the component (A) may occur. , And the insoluble matter tends to precipitate on the surface.

On the other hand, when the amount of the component (D) is less than 0.1 part by weight, the sensitivity is low and the exposure takes a long time. When the amount exceeds 10 parts by weight, the sensitivity is not improved for the amount. At an economic disadvantage.

The preferred mixing ratio of each of these components is as follows:
Component (B) is 30 to 1 with respect to 100 parts by weight of component (A).
00 parts by weight, component (C) 20 to 100 parts by weight, (D)
The components are selected in the range of 1 to 5 parts by weight.

A photopolymerizable monomer can be added to the photosensitive resin composition of the present invention, if desired. The photopolymerizable monomer is an addition-polymerizable compound having at least one ethylenically unsaturated group and is compatible with other components.

Examples of such photopolymerizable monomers include acrylic acid esters or methacrylic acid esters of polyhydric alcohols, glycerin diacrylate or dimethacrylate, diethylene glycol monoacrylate or monomethacrylate, diethylene glycol diacrylate or dimethacrylate, trimethacrylate. Ethylene glycol diacrylate or dimethacrylate, hexanediol diacrylate or dimethacrylate, trimethylolpropane triacrylate or trimethacrylate, pentaerythritol triacrylate or trimethacrylate, pentaerythritol tetraacrylate or tetramethacrylate, or epoxy compound and acrylic acid or methacrylic acid Addition reaction product, a compound having a carboxyl group and Addition products of glycidyl acrylate or glycidyl methacrylate, addition products of compounds having a primary or secondary amino group and glycidyl acrylate or glycidyl methacrylate, acrylamide, methacrylamide, methylenebis Examples include acrylamide compounds such as acrylamide, methylenebismethacrylamide, diacetone acrylamide, and triacrylformal, and unsaturated urethane compounds obtained by an addition reaction of an ethylenically unsaturated compound having a hydroxyl group with isocyanate. These ethylenically unsaturated compounds may be used alone or in combination of two or more. It is preferable that the addition ratio of the photopolymerizable monomer is not more than 100 parts by weight based on 100 parts by weight of the component (A). If the amount exceeds 100 parts by weight, the effect of the present invention may not be sufficiently achieved, which is not preferable.

Further, in the present invention, a thermal polymerization inhibitor, a coloring agent such as a dye or a pigment, a plasticizer, a surfactant, etc., which are conventionally used in a photopolymerizable resin composition, are appropriately blended as long as they do not hinder. It can also be used.

The photosensitive resin composition of the present invention is obtained by homogeneously mixing the required amounts of the above components (A), (B), (C), (D) and various additives used as required. Can be prepared. In order to prepare a printing plate using the photosensitive resin composition of the present invention thus prepared, for example, calendering on a support, coating, compression molding, extrusion molding and other known methods. What is necessary is just to shape | mold into a sheet with a uniform thickness, and to form a photosensitive layer. As the support, a metal plate of aluminum, steel, stainless steel, zinc, magnesium or the like, or a sheet of a synthetic resin such as polyethylene terephthalate, polypropylene, or a cellulose derivative is generally used to improve dimensional accuracy and mechanical strength. Is preferred. When such a support is used, an adhesive layer, an antihalation layer, or an antihalation layer / adhesive layer can be provided between the photosensitive resin layer and the support as necessary.

[0027]

The negative photosensitive resin composition of the present invention can be completely water-developable by using a specific vinyl alcohol polymer, urea derivative, unsaturated acryl urethane oligomer and photopolymerization initiator. It can provide a printing plate having excellent water resistance and printability, and is particularly suitably used as a negative photosensitive resin composition for letterpress printing.

[0028]

Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

Production Example 1 Production of polyvinyl alcohol A-1 etherified with N-methylolacrylamide Polyvinyl acetate 100 having a polymerization degree of 500 and a saponification degree of 80%
100 parts by weight of water and 20 parts by weight of methyl alcohol were added to the parts by weight and dissolved at 80 ° C. To this were added 30 parts by weight of N-methylolacrylamide, 0.1 part by weight of methylhydroquinone and 1 part by weight of 85% by weight phosphoric acid,
After reacting at 80 ° C. for 3 hours, the mixture was neutralized with ammonia, and the reaction product was added to 1,000 parts by weight of acetone with vigorous stirring, and the deposited precipitate was filtered and dried, and polyvinyl ether etherified with N-methylolacrylamide was used. Alcohol A-1 was obtained.

Production Example 2 Production of polyvinyl alcohol A-2 etherified with N-methylolacrylamide Polyvinyl acetate 100 having a polymerization degree of 500 and a saponification degree of 88%
100 parts by weight of water and 20 parts by weight of methyl alcohol were added to the parts by weight and dissolved at 80 ° C. To this were added 35 parts by weight of N-methylolacrylamide, 0.1 parts by weight of methylhydroquinone and 1 part by weight of 85% by weight phosphoric acid,
After reacting at 80 ° C for 3 hours, neutralize with ammonia water,
The reaction product was added to 1,000 parts by weight of acetone with vigorous stirring, and the deposited precipitate was filtered and dried to obtain polyvinyl alcohol A-2 etherified with N-methylolacrylamide.

Production Example 3 Production of Condensate B-1 of Dimethylolacrylamide and Urea 0.07 parts by weight of methylhydroquinone and 1.4 parts by weight of ammonium chloride were dissolved in 30 parts by weight of water.
Parts by weight, 138 parts by weight of N-methylolacrylamide were added, and the mixture was reacted for 2 hours while maintaining the temperature at 80 ° C., and the reaction product was added to 1,000 parts by weight of acetone with vigorous stirring, and the deposited precipitate was filtered and dried. Desired condensate B
-1 was obtained.

Production Example 4 Production of condensate B-2 of dimethylol urea dimethyl ether and N-methylol acrylamide 0.025 parts by weight of methylhydroquinone was dissolved in 10 parts by weight of water, and dimethylol urea dimethyl ether 74 was added thereto.
Parts by weight, N-methylol acrylamide 202 parts by weight,
After adding 2 parts by weight of ammonium chloride and reacting at 80 ° C. for 2 hours, the reaction product was added to 1,000 parts by weight of acetone with vigorous stirring, and the precipitated precipitate was filtered and dried to obtain the desired condensate B. -2 was obtained.

Production Example 5 Production of unsaturated acrylic urethane oligomer C-1 Diethylene glycol, 1,6-hexanediol, dimethylolpropionic acid and adipic acid were mixed at a molar ratio of 2:
Using a 5: 3: 7 ratio to form a polyester first, 2 moles of xylylene diisocyanate are reacted with 1 mole of the polyester, and then 2 moles of 2-hydroxyethyl methacrylate is added thereto. Unsaturated acrylic urethane oligomer C-1 was obtained.

Example 1 100 parts by weight of A-1 obtained in Preparation Example 1, 100 parts by weight of B-2 obtained in Preparation Example 4, 50 parts by weight of C-1 obtained in Preparation Example 5, pentaerythritol triacrylate 20 Parts by weight, 3 parts by weight of benzyl dimethyl ketal, 0.05 parts by weight of methylhydroquinone and 150 parts by weight of water were stirred and stirred in a flask kept at 90 ° C., and uniformly dissolved on a 0.17 mm-thick iron substrate. And then dried at 40 ° C. for 15 hours to obtain a negative photosensitive resin layer having a dry thickness of 0.4 mm. On this layer, a test negative film and N
o. 2 step tablets (manufactured by Kodak Company) are stacked and adhered in vacuum, and a chemical lamp [FL4 manufactured by Toshiba
OBL type] for 4 minutes from a distance of 2.4 cm, and unexposed parts were washed out with warm water of 30 ° C. for 1 minute and 30 seconds using a brush type dissolution machine. Next, it was dried at 100 ° C. for 5 minutes, and further exposed to light for 5 minutes using the above-mentioned chemical lamp.

As a result, no. The number of insolubilization stages by the step tablet No. 2 was 16. The image reproducibility was as shown in Table 1. When this plate was immersed in water at 25 ° C. for 2 hours, it was confirmed that only the relief surface swelled by 5% in thickness, the image area was firm, and the water resistance was excellent. In addition, this version
The plate was not cracked even if it was bent to a high degree, and was very flexible. On the other hand, when this plate was printed with a newspaper letterpress rotary press using an aqueous emulsion ink, a sharp image was maintained for 3 hours or more even when printing was performed at a speed of 100,000 copies per hour.

Comparative Examples 1 to 5 A printing plate was prepared in the same manner as in Example 1 using a negative photosensitive resin composition having the composition shown in Table 1, and its performance was evaluated. Table 1 shows the results. From these results,
It was confirmed that each of the component (A), the component (B), and the component (C) is important in producing a printing plate having water resistance and flexibility.

[Table 1] (Note) 1) Regarding the state of the image area after immersion in water at 25 ° C for 2 hours, 〇 indicates no change, △ indicates that a part of the thin line swells and the relief is broken, and × indicates all the relief swells. And do not retain the original form of the relief. 2) The degree of cracking when bent at 180 ° is indicated by flexibility, Δ indicates an unbreakable item, and X indicates a crackable item. 3) Kodak's Step Tablet No. Indicates the number of insolubilization stages when 2 is used. 4) The limit value at which the halftone dot density of 65 lines / inch is reproduced. 5) Indicates the minimum reproducible line width (μm). 6) Depth (μm) of the 0.5 mm white portion after plate making.

Example 2 100 parts by weight of A-2 obtained in Preparation Example 2, 100 parts by weight of B-1 obtained in Preparation Example 3, 40 parts by weight of C-1 obtained in Preparation Example 5, 2 parts by weight of benzyl methyl ketal Parts, methylhydroquinone 0.05 parts by weight and water 130 parts by weight in a flask kept at 90 ° C. while uniformly dissolving the solution to a predetermined thickness on an antihalation layer provided on an iron substrate. After casting, the film was dried at 40 ° C. for 15 hours to obtain a negative photosensitive resin layer having a thickness of 0.5 mm when dried. On this layer, a negative film for test and 2 step tablets (manufactured by Kodak Co., Ltd.) are stacked and vacuum deposited, and a chemical lamp [FL40BL type manufactured by Toshiba Corporation] is used.
After exposing for 5 minutes from a distance of 2.4 cm using a brush, an unexposed portion was washed out with warm water of 30 ° C. for 2 minutes using a brush type dissolution machine. Then, it was dried at 100 ° C. for 5 minutes, and further exposed to light for 10 minutes using the above-mentioned chemical lamp.

As a result, no. The number of stages of insolubilization using the step tablet No. 2 was 15. In addition, a halftone dot of a 2% highlight portion of a minimum line width of 30 μm and 65 lines / inch remained. Further, when this plate was immersed in water at 25 ° C. for 2 hours, the state of the image area did not change and the plate did not break even when bent at 180 °. Also, 0.5mm
The depth of the white portion after plate making was 250 μm.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-64-29836 (JP, A) JP-B1-48528 (JP, B2) JP-B-49-5923 (JP, B1) (58) Field (Int.Cl. ⁶ , DB name) G03F 7/032 G03F 7/027

Claims (1)

(57) [Claims] (A) a vinyl alcohol polymer having an average degree of polymerization of 200 to 2,000 etherified with lower alkylol acrylamide or lower alkylol methacrylamide, (B) urea, thiourea or lower alkylation thereof. A condensate of a lower alkylolated or lower alkyl lower alkylolated derivative with a lower alkylol acrylamide or a lower alkylol methacrylamide,
A negative photosensitive resin composition comprising (C) a polyester oligomer having an acrylic or methacrylic group at both ends via urethane bonds and (D) a photopolymerization initiator.