JP3441054B2 - Photosensitive resin printing plate and 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 photosensitive resin printing plate, in particular relief printing and a photosensitive resin composition used therefor, and more specifically to process color printing in which the dot gain in the highlight portion is reduced. It relates to a suitable photosensitive resin printing plate.

[0002]

2. Description of the Related Art In the field of photosensitive resin letterpress printing, printing plates suitable for process color printing have been demanded by users. Particularly, printing pressure thickening (dot gain) in a high frequency highlight portion is large and high. There is a problem that quality printed matter cannot be obtained. This problem is considered to be caused by the large deformation of the relief top due to the printing pressure peculiar to letterpress printing.

Therefore, as means for reducing the dot gain, for example, JP-A-55-6392 and JP-A-62-162.
A so-called cap plate having a two-layer structure in which the upper layer is hard and the lower layer is soft is proposed as described in JP-A-296142 and the like. However, since this method requires the use of two kinds of resins, there is a drawback in that the manufacturing process, process, apparatus, etc. are complicated in both the liquid photosensitive resin and the solid photosensitive resin.

Further, as described in Japanese Patent Application Laid-Open No. 4-251255, there is a means for making the relief top portion thin (dot loss) in advance with respect to the negative. However,
In this method, there is a risk that the polymerization inhibitor contained in the slip coat layer migrates to the interface or the photosensitive layer and it becomes difficult to control the dot loss rate.

In order to improve the dot gain with a further resin without using a complicated process or structure in order to solve such a problem, in Japanese Patent Laid-Open No. 9-80743, an ultrafine hardness tester DUH201 was used to measure 150. A method is proposed in which the dynamic hardness of the halftone dot surface of the line 3% is 0.05 or more and 0.5 or less. However, in this method, the relationship between the halftone dot dynamic hardness and the solid portion dynamic hardness is taken into consideration. Therefore, the solid portion has a high dynamic hardness and the halftone dot surface has a smaller dynamic hardness than the solid portion. In this case, there is a problem that the dot gain of highlight cannot be solved if the printing pressure is increased in order to improve the ink coverage on the solid portion.

[0006]

SUMMARY OF THE INVENTION The present invention provides a photosensitive resin printing plate suitable for process color printing in which the above-mentioned conventional problems are solved and the dot gain of the highlight portion is reduced.

[0007]

In order to solve the above problems, the present invention was conducted sincerely examining a photosensitive resin printing plate.
It has been found that the above problems can be solved in a photosensitive resin printing plate in which the microhardness of the halftone dot surface of 3% of 50 lines and the microhardness of the solid portion are within a specific range, and finally the present invention has been completed. . That is, the present invention relates to an ultra-micro hardness meter DUH201.
The dynamic hardness of the surface of 150% 3% halftone dot measured by
A photosensitive resin printing plate characterized in that it is 0.94 or more and 4.0 or less, and the dynamic hardness of the halftone dot surface of 3% at 150 lines is 60% or more of the dynamic hardness of the solid surface. is there.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
First, the dynamic hardness used in the present invention is 25 to 30 ° C. and 7 using a Shimadzu dynamic micro hardness meter DUH-201.
It is a value calculated by the following formula, measured under the following measurement conditions under an environment of 0 to 75%. Test mode: Test for soft materials (MODE3) Indenter: Triangle cone indenter 115 ° Test load: 0.21 gf to 2.00 gf is changed according to hardness of sample Load speed: 10 (0.0145 gf / sec) Displacement full scale The plate making conditions of the printing plate (relief) for measuring the dynamic hardness were as follows. The exposure machine was an ultra-high pressure mercury lamp with an illuminance of 270 W / m ² , and the negative was a performance inspection negative including halftone dots and fine lines, independent points, and white spots.
The main exposure is performed with the minimum exposure time that the μ slit depth is 40 μ or more and the halftone dot of 150 lines and 2% is reproduced, and after the appropriate development step and drying step, the post exposure is performed for the same time as the main exposure,
It was subjected to measurement.

Concretely, a sample of 150% 3% halftone dots and a solid part of the relief prepared under the above plate making conditions is set on a sample stand, and the central part of the halftone dot surface or the center of the solid part is attached by an attached metallographic microscope. The first measurement was performed by adjusting the indenter so that the indenter descends. After the measurement was completed, it was confirmed that the surface detection points, which are the basis for calculating the actual load and the actual indentation depth, did not deviate and proceeded to the next measurement. From the second time onward, a measurement part at least 400 μm apart from the part measured at the first time was searched by the XY stage, and three or more measurements were performed. After the measurement was completed, the dynamic hardness at an actual indentation depth of 5 μ was picked up from the analysis data to obtain the dynamic hardness of the sample. This dynamic hardness (DH) is the hardness obtained from the load and the depth of pushing in the process of pushing the indenter and is defined by the following formula. DH = αP / D ² α: Constant depending on the shape of the indenter In the case of a 115 ° triangular cone indenter 37.838 P: Test load (gf) D: Indentation depth (μ)

An important point of the present invention is that the dynamic hardness of the solid surface measured under the above conditions is 0.05 or more and 4.0 or more.
The following (preferably 0.07 or more and 3.0 or less, particularly preferably 0.08 or more and 2.5 or less) and 150 lines 3%
The halftone dot surface dynamic hardness is 60% or more (preferably 70% or more, particularly preferably 80% or more) of the dynamic hardness of the solid surface. If the dynamic hardness of the surface of 150% 3% halftone dot is less than 0.05, the deformation due to the printing pressure is large, so that the marginal becomes large, and if it exceeds 4.0, the margin is too hard and the ink does not ride well. Wake up. Also, 150 lines 3% halftone dot surface dynamic hardness is 60% or more of the dynamic hardness of the solid surface,
It is important to show preferably 70% or more. 60
If it is less than%, when a high printing pressure is applied in order to put the ink on the solid part, the deformation of the halftone dot becomes large, and the dot gain of the halftone dot part cannot be avoided.

The above-mentioned 150-line 3% halftone dot surface dynamic hardness is 0.94 or more and 4.0 or less, and the 150-line 3% halftone dot surface dynamic hardness is 60% or more of the solid surface hardness. As a method, it is important to increase the hardness of the halftone dot portion, and as a specific method, a method of increasing the hardness by the structure of the crosslinkable group of the ethylenically unsaturated compound,
It is conceivable to use a method of improving the crosslink density and the like, but the method is not limited thereto. In the present invention, a method of increasing the halftone hardness by the structure of the crosslinkable group is preferable, and the ethylenically unsaturated compound is By using a photosensitive resin composition having at least two or more methacryloyl groups or acryloyl groups and containing 50% or more methacryloyl groups, it is possible to increase the halftone hardness.

Specific examples of the ethylenically unsaturated compound include methacrylate monomers such as glycerin dimethacrylate, glycerin acrylate methacrylate, and diethylene glycol dimethacrylate, and epichlorohydrin such as diethylene glycol epichlorohydrin-modified dimethacrylate and ethylene glycol epichlorohydrin-modified acrylate methacrylate. Modified methacrylate-based monomer, phthalic acid-based dimethacrylate such as dimethacrylate of phthalic acid ethylene oxide adduct, dimethacrylate-based monomer of phthalic acid-ethylene oxide adduct such as acrylate methacrylate of phthalic acid-based ethylene oxide adduct, trimethylolpropane epicudrine modified dimethacrylate, trimethylolpropane epi click Roruhi Include phosphorus-modified dimethallyl rate acrylate trimethylolpropane epichlorohydrin modified <br/> methacrylates over preparative monomers such as, but not limited thereto. Of these, dimethacrylate of glycerin and ethylene glycol epichlorohydrin-modified dimethacrylate are particularly preferable. These ethylenically unsaturated compounds may be used alone is not such it may be a mixture of two kinds.

In addition to the above, as the photosensitive resin composition for use in the present invention other than the above, known ones can be used. Specifically, as the soluble polymer compound, polyvinyl alcohol and tertiary nitrogen atom can be used. Containing polyamide (for example, JP-A-53-36555), polyether amide (JP-A-55-79437), polyether ester amide (JP-A-58-117537), diamine having amide bond and organic Addition polymer with diisocyanate compound (JP-A-58-140737), addition polymer with diamine having no amide bond and organic diisocyanate compound (JP-A-2-212111).
7), polyvinyl alcohol / ethylene oxide adduct (JP-A-3-2757), and the like. Examples of the photopolymerization initiator include benzyl dimethyl ketal and benzdimethyl ether. If necessary, a photosensitive resin composition containing a thermal polymerization inhibitor, a plasticizer, a surfactant, a dye and the like can be used.

Next, as a method for obtaining the composition of the present invention, first, a soluble polymer compound, an ethylenically unsaturated compound, a photopolymerization initiator, and optionally a thermal polymerization initiator are mixed, and this method is a known method. Can be performed according to the method of. For example, a method of mixing in a molten state, a method of removing the solvent after mixing with an appropriate solvent such as alcohol, and the like can be mentioned. Further, the composition of the present invention can be made into a sheet such as a plate, film or foil having a desired thickness by any method such as hot pressing, casting, melt extrusion or solution casting. In addition, this sheet material can be laminated on a support with or without a known adhesive.

As the support, any material such as steel, aluminum, glass, a plastic film such as a polyester film, and a film deposited with aluminum can be used.

[0016]

EXAMPLES The present invention will now be specifically described with reference to examples, but the present invention is not limited to these examples. The term "parts" means "parts by weight". The dot gain was measured by the following method. Dot gain: The halftone dot area ratio of a printed matter of 150 lines 3 % was measured using a handy type reflection densitometer DM-800 manufactured by Dai Nippon Nippon Screen Co., Ltd. The measurement is performed 5 points per print,
The size of the dot gain was judged by the average value of the total.

Example 1 4 parts of 2-methylpentamethylenediamine, N, N'-
14 parts of bis (3-aminopropyl) piperazine were dissolved in methanol, and polyethylene glycol (average molecular weight 6
00) 600 parts and hexamethylene diisocyanate 37
82 parts of a urethane oligomer having an isocyanate group at both ends by reacting with 0 part was gradually added to a solution of diamine with stirring. Both reactions were completed in 10 minutes. The polymer obtained by placing this solution on a Teflon-coated petri dish, removing methanol by evaporation, and drying under reduced pressure contained 50% polyethylene glycol chains in the main chain and had a specific viscosity of 1.55. Polymer 5 obtained
5 parts was dissolved in 200 parts of methanol, and 3.1 parts of adipic acid was added to this solution and dissolved. 34 parts of glycerin dimethacrylate, 5 parts of N-ethyl-P-toluenesulfonamide, 0.1 part of hydroquinone monomethyl ether and 1 part of benzyl dimethyl ketal were added to this solution to obtain a photosensitive resin composition solution.

This solution was cast on a Teflon-coated petri dish, and methanol was removed in a dark room.
It was dried under reduced pressure at 0 ° C. to obtain a composition sheet having a thickness of about 800 μ. This sheet was stuck to a 250μ PET film coated with 20μ of brown pigment-containing adhesive, and 2μ of polyvinyl alcohol was further coated on the upper surface of the composition to give a thickness of 1
It was covered with a 25 μm PET film and hot pressed at 110 ° C. to prepare a photosensitive resin original plate having a photosensitive resin layer thickness of 700 μm. Then, the cover film was peeled off from the original plate, and an inspection negative was brought into close contact with the surface of the photosensitive resin and exposed for 30 seconds. After removing the negative, the film was developed with neutral water at 25 ° C. for 3 minutes and dried at 70 ° C. for 10 minutes. The obtained relief had a dynamic hardness of 1.43 for halftone dots at 150% and 3%, and a dynamic hardness of 1.41 for solid areas. Using this plate, a rotary printing machine (P-2 manufactured by Sanjo Kikai Seisakusho Co., Ltd.)
0) UV Best Cure No5 BF made by T & K
It was printed using black ink. When the dot gain of the obtained printed matter was measured by the above-described evaluation method, the dot gain was found to be reduced. The results are shown in Table 1 together with the following examples.

Comparative Example 1 A composition was prepared in the same manner as in Example 1 except that glycerin diacrylate was used instead of glycerin dimethacrylate in Example 1, and a relief was prepared. The resulting relief had a dynamic hardness of 0.36 for halftone dots at 150% and 3%, and a dynamic hardness of 0.82 for solid areas. This plate was used to print on a rotary printing press. When the dot gain of the obtained printed matter was measured by the above-mentioned evaluation method, the dot gain was not reduced.

[0020]

[0021]

Example 4 55 wt% of an equimolar salt of α, ω-diaminopolyoxyethylene and adipic acid obtained by adding acrylonitrile to both terminals of polyoxyethylene glycol having a number average molecular weight of 600 and reducing it with hydrogen. Part, 25 parts by weight of ε-caprolactam, and 20 parts by weight of an equimolar salt of hexamethylenediamine and adipic acid are melt-polymerized under normal conditions to obtain a relative viscosity (polymer-1 g is dissolved in chloral hydrate 100. ,
A polyamide of 2.1) (measured at 25 ° C.) was obtained. 55 parts of the obtained polymer was dissolved in 200 parts of methanol, and 39 parts of glycerin dimethacrylate, N-ethyl-
P-toluenesulfonamide 5 parts, hydroquinone monomethyl ether 0.1 part, benzyl dimethyl ketal 1
Parts were added to obtain a photosensitive resin composition solution. The obtained photosensitive resin composition solution was operated in the same manner as in Example 1 to prepare a photosensitive resin original plate, and the developing time was changed to 3 minutes and 45 seconds to prepare a relief. The obtained relief had a dynamic hardness of 0.94 for halftone dots at 150% and 3%, and a dynamic hardness of 1.13 for a solid portion. This plate was used to print on a rotary printing press. When the dot gain of the obtained printed matter was measured by the above-described evaluation method, the dot gain was found to be reduced.

Example 5 Nylon salt of 500 parts by weight of ε-caprolactam, N, N'-bisaminopropylpiperazine and adipic acid 45
0 parts by weight of 1,3-bis (aminomethyl) cyclohexane and 50 parts of adipic acid nylon salt are polymerized,
A polyamide having a tertiary nitrogen atom and a specific viscosity of 2.40 was obtained. 55 parts of the polyamide thus obtained was dissolved in 200 parts of methanol, and 3 parts of methacrylic acid was added to this solution.
Glycerin dimethacrylate 36 parts, N-ethyl-P-
5 parts of toluenesulfonamide, 0.1 part of hydroquinone monomethyl ether and 1 part of benzyl dimethyl ketal were added to obtain a photosensitive resin composition solution. The obtained photosensitive resin composition solution was operated in the same manner as in Example 1 to prepare a photosensitive resin original plate, and the developing time was changed to 2 minutes and 45 seconds to prepare a relief. The obtained relief had a dynamic hardness of 2.14 for halftone dots at 150% and 3%, and a dynamic hardness of 3.39 for solid areas. This plate was used to print on a rotary printing press. When the dot gain of the obtained printed matter was measured by the above-described evaluation method, the dot gain was found to be reduced.

Comparative Example 2 A composition was prepared in the same manner as in Example 1 except that ethylene glycol epichlorohydrin-modified acrylate was used instead of glycerin dimethacrylate in Example 1, and a relief was prepared. The obtained relief had a dynamic hardness of 0.65 for halftone dots at 150% and 3%, and a dynamic hardness of 1.22 for solid areas. With this edition,
Printing was performed with a rotary printing machine. When the dot gain of the obtained printed matter was measured by the above-mentioned evaluation method, the dot gain was not reduced.

Comparative Example 3 Nylon salt of 610 parts by weight of ε-caprolactam, N, N'-bisaminopropylpiperazine and adipic acid 49
0 parts by weight of and were polymerized to obtain a polyamide having a tertiary nitrogen atom and a specific viscosity of 2.20. 55 parts of the polyamide thus obtained was dissolved in 200 parts of methanol,
6 parts of methacrylic acid, 33 parts of epicudrine-modified diacrylate of bisphenol A, N-ethyl-P-
5 parts of toluenesulfonamide, 0.1 part of hydroquinone monomethyl ether and 1 part of benzyl dimethyl ketal were added to obtain a photosensitive resin composition solution. The obtained photosensitive resin composition solution was operated in the same manner as in Example 1 to prepare a photosensitive resin original plate, and the developing time was changed to 3 minutes and 15 seconds to prepare a relief. The resulting relief had a dynamic hardness of 2.08 for halftone dots at 150% and 3% for a solid portion of 4.52. This plate was used to print on a rotary printing press. When the dot gain of the obtained printed matter was measured by the above-mentioned evaluation method, the dot gain was not reduced.

Example 6 A composition was prepared in the same manner as in Comparative Example 3 except that glycerin dimethacrylate was used instead of the epicurhydrin-modified diacrylate of bisphenol A in Comparative Example 3 to prepare a relief. The obtained relief had a dynamic hardness of 3.04 for halftone dots at 150% and 3%, and a dynamic hardness of 4.41 for solid areas. With this edition,
Printing was performed with a rotary printing machine. When the dot gain of the obtained printed matter was measured by the above-mentioned evaluation method, the dot gain was not reduced.

Comparative Example 4 A composition was prepared and a relief was prepared in the same manner as in Example 1 except that epichlorohydrin-modified triacrylate of trimethylolpropane was used in place of glycerin dimethacrylate. The obtained relief had a dynamic hardness of 0.20 for halftone dots at 150% and 3%, and a dynamic hardness of 0.46 for solid areas. This plate was used for printing on a rotary printing press. When the dot gain of the obtained printed matter was measured by the above-mentioned evaluation method, the dot gain was not reduced.

[0028]

[0029]

[Table 1] In Table 1, dot gain: ◎ halftone dot area ratio is 10% or less ○ halftone dot area ratio exceeds 10% and 20% or less × halftone dot area ratio exceeds 20%

[0030]

As is apparent from Table 1, in the photosensitive resin plate of the present invention having the above-mentioned constitution, the dynamic hardness of the halftone dot surface and the dynamic hardness of the solid surface are controlled within a specific range. It is possible to obtain good process color printed matter with reduced dot gain, which is a great contribution to the industrial world.

─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-9-185168 (JP, A) JP-A-3-215038 (JP, A) JP-A-2-1852 (JP, A) JP-A-4- 240855 (JP, A) JP 9-80743 (JP, A) JP 6-64358 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03F ^7/ 00-7 / 18

Claims (2)

(57) [Claims] 1. An ultra-micro hardness meter DUH201 was used to measure 15.
The dynamic hardness of the 0% 3% halftone dot surface is0.94 or more
Dynamics of less than 4.0 and 150% 3% halftone dot surface
Hardness is 60% or more of the dynamic hardness of the solid surface
Is a photosensitive resin printing plate. 2. Deletion.