JPH0336424B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reducing liquid used when performing a reducing process on a formed image. More specifically, an image duplicating material having an alkali-developable photosensitive resin layer containing a colorant on a support, or an alkali-soluble resin layer containing a colorant between the support and an alkali-developable photosensitive resin layer. The present invention relates to a reducing liquid used when reducing an image of an image forming material obtained by image exposure and development of an image duplicating material.

Currently, in the production of halftone images in the prepress industry,
Silver halide photosensitive lithium film (hereinafter referred to as silver salt lithium film) is used, and in order to change the density of the halftone dot image on the silver halide lithographic film, a so-called reduction force is used to partially thin the halftone dots. is being carried out. This reduction method involves applying a reduction solution that oxidizes and dissolves the precipitated silver in the film, such as a reduction solution containing sodium thiosulfate and potassium ferricyanide, to a part of the image after the development process, or The halftone image is reduced in strength by applying a substance containing potassium permanganate and sulfuric acid, or a substance containing EDTA-iron salt and sodium thiosulfate. However, by reducing the force using the above method, the area of the halftone dots decreases, and at the same time,
The disadvantage is that the overall halftone density decreases. Furthermore, the reducing solution for silver salt lithium film is problematic because it contains compounds that cause pollution and its pH is in an unfavorable range for use.

On the other hand, recently, image duplicating materials having a photosensitive resin layer containing a coloring agent on a support and a resin layer containing a coloring agent between the support and the photosensitive resin layer have been recently introduced as an alternative to the silver salt lithographic film. There are image duplication materials (hereinafter referred to as non-silver salt lithium film) that have
After image exposure, the resin layer in the exposed or unexposed areas swells and dissolves depending on the characteristics of the photosensitive resin layer by contacting or immersing it in an alkaline aqueous solution, making it visible to the naked eye. It appears as an image.

When reducing the strength of a halftone dot image formed using the image duplicating material, a so-called side etching method is used in which a reducing liquid penetrates from the sides of the halftone dots to swell and dissolve the photosensitive resin layer. Therefore, it is possible to bring about a great effect that cannot be obtained by reducing the force of the conventional silver salt lithium film, which is that only the area of the halftone dots can be changed without reducing the optical density of the halftone dots as a whole. However, on the other hand, since the reducing liquid must be etched from only a few sides of the halftone dot, the reducing liquid penetrates unevenly, resulting in uneven etching of the image and poor halftone dot shape. There are many things that can be mentioned. In addition, it takes a long time to achieve the required force reduction range, and pinholes occur. Therefore, despite the above-mentioned limitations of such a reducing liquid, etching can be carried out at a practically sufficient speed. Furthermore, it is required that the halftone dot shapes be similar before and after reducing the force.

In general, as a reducing liquid for non-silver salt lithium film,
Mention may be made of alkaline aqueous solutions and alkaline aqueous solutions containing organic solvents. For example, Tokukai Akira
As aqueous solutions and organic solvents of sodium hydroxide, potassium hydroxide, sodium phosphate, sodium carbonate, sodium aluminate, and trisodium phosphate described in Publications 52-99103 and 52-99101,
These are lower alcohols such as methyl alcohol and ethyl alcohol, and oxyethers such as methyl cellosolve and ethyl cellosolve. Although these reducing liquids have performance in terms of reducing halftone images, it is difficult to control the reducing speed, it is difficult to obtain reproducibility, and it takes time to achieve the required reducing width. In addition to these drawbacks, even bigger problems include poor halftone dot shape, incongruent shapes before and after reduction of force, and pinholes. Furthermore, in order to obtain the necessary reduction width, the pH of the alkaline aqueous solution must be 12 or higher, which is dangerous to the human body during reduction work, and it is also desirable to color the reduction liquid using dyes, pigments, etc. In this case, it is pointed out that the dispersion stability of the colored liquid is poor due to strong alkalinity.

Therefore, an object of the present invention is to obtain a good reduction speed when reducing the force of a halftone image formed using an image duplicating material, and to ensure that the shape of the halftone dots is similar before and after the reduction of force, and that the shape of the halftone dots is similar before and after reduction of force, To provide a reducing liquid which does not cause pinholes in halftone dots, has a low pH value and can be colored despite being an alkaline liquid.

The inventors of the present invention have made extensive studies to achieve the above object, and as a result, have finally completed the present invention. That is, the present invention provides an image duplicating material having an alkali-developable photosensitive resin layer containing a colorant on a support, or an alkali-soluble resin layer containing a colorant between the support and the alkali-developable photosensitive resin layer. A reducing liquid used when reducing an image of an image forming material obtained by image exposure and development processing of an image duplicating material having an alkali metal compound and ammonium ion. This is a reducing liquid for image forming materials, characterized in that it is an alkaline aqueous solution.

First, the image forming material to which the reducing liquid of the present invention can be applied is an image duplicating material having an alkali-developable photosensitive resin layer containing a colorant on a support, or an image-forming material between the support and the alkali-developable photosensitive resin layer. It is an image forming material obtained by imagewise exposing and developing an image duplicating material having an alkali-soluble resin layer containing a colorant, and the support is polyester, polypropylene, polyethylene, polyvinyl chloride, polyvinylidene chloride. , polycarbonate,
Examples include films such as cellulose acetate, and plates such as glass and acrylic resin plates depending on the use, but polyester films are preferred from the viewpoint of dimensional stability and transparency.

Various types of alkali-developable photosensitive resins can be used, such as photopolymerization type, photocrosslinking type, and photolytic insolubilization type, but photopolymerization type photosensitive resins are most preferred from the viewpoint of photosensitivity. The photopolymerizable photosensitive resin is mainly composed of a photoinitiator, a monomer or oligomer having an ethylenically unsaturated bond, and an alkali-soluble polymer binder. For example, the photoinitiator may include benzophenone derivatives, aromatic Examples include combinations of ketones, benzoin derivatives, 2,4,5-triarylimidazole dimers, and free radical generators. Next, monomers or oligomers with ethylenically unsaturated bonds include alkyl (meth)acrylates, alkyl ethers (meth)
Acrylates, alkyl (meth)acrylamides, (meth)acrylates of polyalkyl ethers, (meth)acrylates of polyhydric alcohols, (meth)acrylic acid and active hydrogen-containing substances,
Alternatively, a reaction product with a glycidyl compound may be mentioned. In addition, as alkali-soluble polymer binders, carboxyl group-containing cellulose derivatives, copolymers of carboxyl group- or sulfonic acid group-containing vinyl monomers and other vinyl monomers, such as methyl methacrylate/methacrylic acid copolymers, methyl methacrylate・Butyl acrylate/methacrylic acid copolymer, 2-acrylamide-2-methylpropanesulfonic acid/methyl methacrylate copolymer, methyl vinyl ether/maleic anhydride copolymer, styrene, maleic anhydride copolymer, etc. be.

Note that the main chain or side chain of the binder may contain a polymerizable unsaturated double bond group.

The thickness of the alkali-developable photosensitive resin layer is preferably 1 μm or more and 15 μm or less from the viewpoint of high resolution.

In the present invention, the alkali-soluble resin layer containing a coloring agent provided between the support and the alkali-developable photosensitive resin layer may be the same as the binder that is the main component of the alkali-developable photosensitive resin. substances can be used.

In the present invention, the alkali-developable photosensitive resin layer or the colorant contained in the resin layer has an ultraviolet and visible absorption spectrum that overlaps with that of the photoinitiator used. Examples of such colorants include ultraviolet absorbers, ultraviolet absorbing dyes, and other dyes and pigments. Examples of these include powders of compounds such as carbon black, titanium oxide, iron oxide, various metals and metal oxides, and sulfides, pigment black (CI50440), chrome yellow light (CI77603), 2,2'-dihydroxy- 4-methoxybenzophenone, 2,4-dihydroxybenzophenone hydroxyphenylbenzotriazole, 2-(2'-hydroxy-5'-methoxyphenyl)benzotriazole, resorcinol monobenzoate, ethyl-2-cyano-
3,3-diphenyl acrylate, toluidine
Yellow GW (CI71680), Molybdenum Orange (CI77605), Sudan Yellow (CI30), Oil Orange (CI12055), etc.

Such colorants are not only useful for the purpose of making the image more visible, but because they absorb actinic radiation, it is possible to use the same image reproduction material further on the basis of the image obtained when the support is transparent. If a large amount of colorant is included in the photosensitive resin layer, a resist image is obtained in which only the upper layer is cured and the lower layer is not cured. It is also effective for the purpose of maintaining force-reducing properties, which is an advantageous characteristic for applications such as

Such a coloring agent can be directly blended into the alkali-developable photosensitive resin layer as described above, or
Alternatively, as the intermediate layer, a method may be adopted in which a colorant is blended into a resin layer made of an alkali-soluble binder and an alkali-developable photosensitive resin layer containing no colorant is provided thereon. In any case, in order to achieve the purpose of blending the colorant, there is a preferred range of blending amount. It is preferred that the absorbance of the layer (combined layer and protective layer) be in the range of 1.5 to 4 within the active light range. Note that, among the colorants mentioned above, when carbon black is used in particular, a good image duplication material can be obtained.

In the present invention, for the purpose of protecting the surface or preventing inhibition of the photopolymerization reaction by oxygen, especially when the alkali-developable photosensitive resin layer is a photopolymerization type,
The alkali-developable photosensitive resin layer may be coated with a removable protective film having good light transmittance, or a protective layer soluble in an aqueous solvent. Therefore, resins such as polyvinyl alcohol, polyacrylic acid, and methyl cellulose that are soluble in aqueous solvents can be used. In particular, polyvinyl alcohol is preferable because it has excellent oxygen barrier properties and can reduce the radical polymerization damage prevention effect caused by oxygen.

In the present invention, the processing liquid used when developing the image duplicating material having the above-mentioned structure after image exposure is one containing water as a main component, such as simple water, sodium hydroxide, potassium hydroxide, An aqueous solution containing an alkaline salt such as sodium borate, sodium carbonate, sodium and potassium pyrophosphate tetrasubstituted phosphonium, an aqueous solution containing an acid such as hydrochloric acid, sulfuric acid or acetic acid, and an organic solvent such as ethylene glycol monoethyl ether added to the above aqueous solution. Examples include aqueous solutions, and aqueous solutions containing metal chelating agents and nonionic surfactants in these aqueous solutions.

The temperature of the processing solution may be room temperature, but
It is easier to achieve the purpose of the present invention by heating it a little.15~
The temperature is preferably 50°C, more preferably in the range of 25 to 40°C.

When forming an image by wash-off using the processing liquid, it can be done by spraying in the processing liquid or by rubbing with a brush, sponge roller, etc. However, as a modification, it is possible to form an image by simply copying the image in the developer. Another effective method is to only penetrate the developer into the area of the material to be removed, and then remove this area by spraying or brushing in water.

The reducing liquid used when reducing the image forming material obtained by the above method is an alkaline aqueous solution containing an alkali metal compound and ammonium ion, and the alkali metal compound includes:
Alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, lithium hydroxide, cesium hydroxide, and rubidium hydroxide, carbonates such as sodium carbonate, potassium carbonate, lithium carbonate, cesium carbonate, and rubidium carbonate, and sodium phosphate. , sodium hydrogen phosphate, potassium phosphate, lithium phosphate, cesium phosphate, rubidium phosphate, and other alkali metal sulfites, aluminates, phosphites, pyrophosphates, tripolyphosphates Examples include.

Next, the compounds that generate ammonium ions to be contained in the reducing fluid of the present invention include triammonium phosphate, diammonium hydrogen phosphate, sodium ammonium hydrogen phosphate, ammonium dihydrogen phosphite, ammonium dihydrogen orthophosphate, Ammonium nitrate, ammonium sulfite, ammonium carbonate, ammonium hydroxide, ammonium bromide, ammonium tribromide, ammonium iodide,
ammonium hydrogen sulfide, ammonium thiosulfate,
Examples include ammonium azide, ammonium carbamate, ammonium formate, and ammonium acetate.

In the present invention, the alkali metal compound;
The mixing ratio with the ammonium compound is such that the concentration of the alkali metal compound is 0.01 to 10% by weight, preferably
0.5 to 4 parts by weight, preferably 1 part by weight of ammonium compound per 1 part by weight of 0.1 to 5% by weight aqueous solution.
~3 parts by weight. In addition, the pH of the present invention reducing fluid is 9~
11, preferably 9.3 to 10.5, and this PH control is achieved by mixing the alkali metal compound and ammonium compound at the above mixing ratio.

If you wish to color the force reducing liquid with a dye to make it easier to see the force reducing area, it can be contained in any proportion, but preferably, the force reducing liquid should be colored with a dye.
It is preferably 0.2 to 0.5 parts per 100 parts. The dye used here is preferably a disperse dye, such as Sumikalon BLue E-FBL, Sumikalon BLue E-BL,
Sumikaron Blue E-B, Sumikaron Blue E-
Examples include G.

The method of using the reducing fluid in the present invention includes:
A force reducing operation is performed by contacting and stroking a force reducing liquid on the image forming portion. Specifically, for example, the material on which the halftone dot image has been formed is immersed in a reducing solution placed in a container for a predetermined period of time, and then stroked with a sponge, etc.; A method of stroking, or a method of soaking a brush in a reducing liquid and applying it to the image surface and stroking it may be adopted.

As described above, by applying the reduction liquid of the present invention having such a configuration to the reduction of force of non-silver salt lithium film, the reduction speed is improved, the reproducibility is good, the halftone dot shape is similar before and after reduction, There are no pinholes in the reduced halftone dots, which is good. In addition, since the reducing liquid of the present invention is not strongly alkaline, it can reduce the effect on the human body, and when it is desired to color the reducing liquid using dyes, pigments, etc., there are problems with poor stability due to deterioration of the dye. This eliminates the occurrence of precipitation, etc.

The present invention will be specifically explained below with reference to Examples. In the examples, parts mean parts by weight.

Example 1 An adhesive layer solution (B) having the following composition was coated on the surface of a polyester film support having a thickness of 100 μm using a reverse coater and dried. Then, the colored photosensitive resin solution (A) was coated on this surface using a reverse coater and dried. The thickness of this photosensitive resin layer was 3 to 4 μm. Further, the protective layer solution (C) was coated with a reverse coater and dried. The image duplication material thus obtained was pattern-exposed using a bright room printer (3KW ultra-high pressure mercury lamp manufactured by Oak Seisakusho) at an exposure dose of 8 mJ/cm ² using a 50% halftone original. )
Then, the photosensitive resin layer in the unexposed area was removed. The support was then immersed in a fixing solution containing 2% by weight of hydroquinone (38°C) for 15 seconds, washed with water, dried, and further exposed from the back side of the support at an exposure dose of 60 mJ/cm ² . The resulting image forming material having 50% halftone dots was reduced using a reducing liquid having the composition shown below, and the results were evaluated.

Reducer: tripotassium phosphate 10g/water 1, sodium ammonium hydrogen phosphate 10
g/1 part of water (Mixed at a mixing ratio of 1:1, the pH of this reducing liquid was measured and it was PH10.2.) To reduce the force, hold the brush on a washing light table. The tests were carried out at 25°C with a reduction time of 10 to 40 seconds.
As a result, 7% in 10 seconds, 11% in 20 seconds, 13% in 30 seconds, 40
The dot area was reduced by 16% per second, the dot shape before and after the reduction was good, and there were no pinholes. When the same force reduction operation as above was repeated, similar results were obtained and it was found that there was good reproducibility.

Solution for colored photosensitive resin (A) Methyl methacrylate methacrylic acid copolymer
…41 parts (70:30 molar ratio) Carbon black …12 Tetraethylene glycol dimethacrylate
…17 Trimethylolpropane triacrylate
…17 2-(2-chloro-1-naphthyl)4.5-diphenylimidazole dimer …8* Hydroquinone monomethyl ether 0.03 Dimedone …3* Michler’s ketone …2* Methanol …140 Chloroform …120 Ethyl acetate …80 n-propyl acetate …40 Isopropyl alcohol …40 Adhesive layer solution (B) Vylon 20S (manufactured by Toyobo Co., Ltd.) …43 parts (saturated polyester adhesive) Coronate L (manufactured by Nippon Polyurethane Industries)
…11 U-cat SA-No102 (manufactured by Sunabbot)
…0.1 Toluene …80 Methyl ethyl ketone …20 Protective layer solution (C) Polyvinyl alcohol (manufactured by Kuraray) …7 parts (degree of saponification 98.5%, degree of polymerization 500) Neugen EA-140 (manufactured by Daiichi Kogyo Seiyaku) …0.4 Methanol …1 Water…92 Photosensitive resin solution (D) Methyl methacrylate/methacrylic acid copolymer
...41 parts (70:30 molar ratio) trimethylolpropane triacrylate
…34 2-(2-chloro-1-naphthyl)4.5-diphenylimidazole dimer …8 Hydroquinone monomethyl ether …0.03 Dimedone …3 Michler’s ketone …2 Methanol …140 Chloroform …120 Ethyl acetate …80 n-propyl acetate … 40 Isopropyl alcohol...40 Developing solution (e) at 30℃ Sodium carbonate...7.5 parts Water...1000 The optical density of the halftone dot area with the power reduced by 14% was measured using a microphotometer (PDM-5 model Konishiroku Photo Industry Co., Ltd.). The optical density of the halftone dot area was measured to be 1.88, which was almost unchanged from the optical density of the halftone dot area of 1.89 before power reduction, and it was found that there was no decrease in the optical density of the halftone dot area due to force reduction. In addition, the disperse dye Sumikalon is used as a coloring agent for the reducing liquid.
When 0.3% by weight was added using BLue-E-FBL, the dispersibility was good and the force reduction properties were similar to the above results. Moreover, this reducing solution remained in a good dispersion state with no precipitate formed even after two months.

Example 2 An image forming material having a halftone dot image prepared in the same manner as in Example 1 was reduced in force using a reducing liquid having the following composition.

A reducing solution was prepared by mixing tripotassium phosphate 10g/1 water, diammonium hydrogen phosphate 10g/1 water (1:1 mixing ratio), and the PH of this reducing solution was measured and found to be 9.37. ) The force reduction was carried out using the same force reduction time as in Example 1, and the results were 5% in 10 seconds, 8% in 20 seconds, 12% in 30 seconds, and 14% in 40 seconds.
The force was reduced, and the force reduction performance was almost the same as in Example 1, and the halftone dot shape was good and no pinholes were generated.
Reproducibility was also good.

Example 3 In the same manner as in Example 1, a polyester film was coated with a solution consisting of the adhesive layer solution (B) and the colored photosensitive resin solution (A) except for the *components, and dried. Further, the photosensitive resin solution (D) was overcoated using a reverse coater and dried. Then, the protective layer solution (C) was coated and dried. The image reproduction material obtained in this way is
A halftone dot pattern was created with an exposure dose of 8 mJ/cm ² in the same manner as in Example 1, and power reduction was performed using the same power reduction liquid as in Examples 1 and 2. As a result, the force reduction properties were almost the same as those of Examples 1 and 2, the halftone dot shape was good, no pinholes were generated, and the reproducibility was good.

Example 4 The mixing ratio of the reducing fluid used in Examples 1 to 3 was 1 part of tripotassium phosphate to 1 part of ammonium hydrogen phosphate,
When the force was reduced using a reducing solution containing 0.5 to 4 parts of diammonium hydrogen phosphate, Examples 1 to 3 were obtained.
The same force reduction properties as in No. 3 were obtained. At this time, the reducing fluid
The pH was within the range of 9-11. In addition, when ammonium hydrogen phosphate was added to 5 parts and the pH was set to 8.5, the deceleration speed was reduced to about 1/2.

Comparative Example 1 An image forming material having a halftone image prepared in the same manner as in Example 1 was subjected to a reduction treatment using a reduction liquid having the following composition.

Reducing liquid Tripotassium phosphate 10g/water 1 (The pH of this reducing liquid was measured and it was 12.54.) Reducing force was carried out with the same reducing time as in the example, and the reduction was 1% in 10 seconds. , 20 seconds 3%, 30 seconds 5%, 3%,
Many pinholes occur in halftone dots that have been reduced by 5%.
The shape of the halftone dots whose power was reduced by % was distorted. In addition, the disperse dye Sumikaron BLue-E-FBL is added to this reducing liquid.
When 0.3% of the dye was added, the dye precipitated after one day, and the dispersion stability was poor.

Comparative Example 2 An image forming material having a halftone image prepared in the same manner as in Example 1 was reduced in force using a reducing liquid having the following composition.

Reducer Sodium Ammonium Hydrogen Phosphate 10
g/water 1 (When the pH of this reducing liquid was measured, it was 8.20.) When the reducing force was carried out using the same reducing time as in the example, the force was reduced by 2% in 30 seconds, and the force was reduced. The speed has slowed down.

Comparative example 3 25℃, diammonium hydrogen phosphate 10g/water 1
When the test was carried out using a reducing liquid (PH: 8.1), the force was reduced by only 1% in 30 seconds, which was a very slow rate of force reduction.

Comparative Example 4 When the force was reduced at 25°C using a reducing solution (PH 11.8) consisting of 10 g of sodium carbonate and 1 part of water, the force decreased to 2 in 10 seconds.
%, 3% for 20 seconds, and 4% for 30 seconds.

Comparative Example 5 When power was reduced using a power reducing solution (PH: 13.7) consisting of 10 g of potassium hydroxide and 1 part of water at 25°C, the power was reduced in 30 seconds.
Although it was possible to reduce the power by 15%, the halftone dot shape was poor and there were too many pinholes, making it impractical.

Comparative Example 6 At 25°C, a reducing solution (PH
11.6) was used to reduce the force by only 6% in 30 seconds.

Comparative Example 7 When the image forming material having the halftone image created in Example 3 was reduced in force at 25°C with a reducing solution consisting of 10 g of sodium carbonate and 1 part of water, it had almost the same force reduction properties as Comparative Example 4. The deceleration speed was slow.

Claims (1)

[Scope of Claims] 1 Image duplicating material having an alkali-developable photosensitive resin layer containing a colorant on a support, or an alkali-soluble material containing a colorant between the support and an alkali-developable photosensitive resin layer A reducing liquid used when reducing an image of an image forming material obtained by image exposure and development of an image duplicating material having a resin layer, the reducing liquid containing an alkali metal compound and an ammonium ion. A reducing liquid for image forming materials, characterized in that it is an alkaline aqueous solution containing. 2. The reducing liquid for image forming materials according to claim 1, wherein the pH of the alkaline aqueous solution is within the range of 9 to 11.