KR20030065767A - Method for preparing film for laser scanner print - Google Patents

Abstract

PURPOSE: Provided is a production method of a film used for preparing a printing plate of laser scanner, which shows graphic properties of high contrast and high resolution of black dot, and apply in multilayer pattern at high speed. CONSTITUTION: The method comprises the steps of (i) simultaneously mixing and reacting an acidic solution containing gelatin and a mixed solution of hydrochloride, potassium bromide, rhodium salt, and iradium salt while adjusting pAg of the solution with silver nitrate solution to be 7.3, so as to form uniform particles having 90% or more of square particle having particle size of 0.2-0.25 micrometer(wherein the particle comprises silver chloride of 80 mol% or more in AgBrCl), (ii) forming photographic emulsion having photosensitive absorption area of 580-710 micrometers by using water-washing/chemical sensitization/sensitized colorant, sequentially adding an additive and a cellulose ether-based thickener to the emulsion, so as to apply a protective layer on the back of polyester film support(on which antihalation is applied) and drying the film.

Description

Method for preparing film for laser scanner printing

The present invention relates to a method for manufacturing a film for laser scanner printing plate, and more specifically, to a printing plate film coated with photosensitive fine silver halide using a 630 μm and a 680 μm wavelength which is a light source of a helium-neon laser device. It relates to a high-sensitivity, high-contrast printing plate-making film obtained by photosensitive in the form of a scanning line, subjected to a developing and fixing process to obtain a photographic image of a high resolution black dot.

Photo emulsion of printing plate making film using a conventional helium-neon laser light source is generally prepared by mixing the salt and silver bromide (AgBrCl) mixed crystal particles by a double injection method while stirring in a gelatin aqueous solution. After washing with water, it is prepared by adding reducing sensitization, chemical sensitization, pigment sensitization, stabilizer and additives.

The physical aging method of silver halide production method is Kang Tae-Sung, Photographic Chemistry, p. 62 (1987, Gwanghwa Publishing Co., Ltd.), by K. Ness, "Theory of photographic process. focal process plate (1964), US Pat. No. 3,276,877, and J of photogr, Science Eng (Hrenlar Vol. 24,619,80).

The proportion of silver bromide produced in this way was 30 mol% or more and the particle size distribution was 0.3-0.4 μm. The color of the black dots developed by a helium-neon laser light source was blackish brown, resulting in low contrast and halftone resolution. I can't get it.

In addition, the film produced as described above has a drawback in that the light source generated in the laser device is fixed at a wavelength of 630 μm and 680 μm so as to produce a printing plate film having respective wavelengths without mutual compatibility.

Therefore, in the present invention, the silver halide composition ratio is 80 mol% or more of silver chloride and 20 mol% or less of silver bromide, and a photo emulsion having a particle size of 0.2 μm to 0.25 μm having a square uniform distribution at an appropriate temperature and an appropriate pAg is prepared. The scanning line dots of the photosensitive film, which were photographed by the scanner, were able to obtain the high contrast and high resolution photographic characteristics of the black dots which are black and blue after the development process, and the spectral wavelengths of 630 µm and 680 µm were obtained using the spectrophotometric dye. It was possible to produce a film for printing plate compatible respectively.

In addition, in the present invention, when the photo-emulsion agent prepared as described above was multi-layered at high speed, a thickener, which is a new compound for adjusting the viscosity, was added to effectively apply the multi-layered coating to the polyester film.

Accordingly, an object of the present invention is to provide a method for producing a film for laser scanner printing plate which exhibits high contrast and high resolution photographic properties of black dots and multilayer coating at high speed.

The method of manufacturing a laser scanner printing plate film of the present invention for achieving the above object is a method for manufacturing a laser scanner printing plate film, an acid solution and a chloride containing gelatin at a temperature range of 45 ~ 60 ℃, A solution containing a mixture of potassium bromide, rhodium salt, and iridium salt was mixed with a silver nitrate solution at a pAg 7.3, and mixed by a double injection method to obtain a square particle containing 80 mol% or more of silver chloride in silver bromide (AgBrCl). After producing uniform particles having a size in the range of 0.2 to 0.25 μm or more and 90% or more, a photoemulsion having a wavelength of 580 to 710 μm is prepared by washing, chemical sensitization, and dye, and then adding an additive and then adding a thickener. It is consisted of applying with a protective layer on the back of the polyester film support to which the antihalation was applied by adding and drying.

1 is a graph showing the particle size distribution of silver halides to be included in a photographic emulsion according to the present invention.

FIG. 2 is a graph showing the spectral sensitivity obtained by adding a chemical sensitizer and a sensitizing dye to the photoemulsion including silver halide prepared according to the present invention.

Hereinafter, the present invention will be described in more detail.

First, in the present invention, a photo emulsion that can be photosensitized by a Helm-neon laser scanner is prepared. The photographic emulsion is a mixture of acidic solution of pH 4-5 containing gelatin and chloride, potassium bromide, rhodium salt and iridium salt in the temperature range of 45 ~ 60 ℃ to adjust the pAg 7.3 with a silver nitrate solution The composition ratio of silver halide is made to be 80 mol% or more, and silver bromide is made to 20 mol% or less by simultaneous mixing reaction by the injection method.

The photoemulsion thus prepared has a square average particle size of 0.2 to 0.25 µm and a uniform particle distribution with a distribution range of 90% or more (see FIG. 1).

The photoemulsion having such particle size and distribution can obtain high contrast and high resolution photographic properties of black dots that have black-and-white dots after the developing process.

Next, the photographic emulsion is coated on a backside of the polyester film coated with antihalation with a protective layer in a thickness of 4 to 4.5 μm and dried to prepare a scanner printing plate photographic film for a laser light source.

In this case, in the present invention, a thickener, which is a new compound for adjusting the viscosity, is applied to the polyester film in order to effectively apply the multilayer film to the polyester film at high speed.

On the other hand, the photo emulsion prepared as described above is washed with Noodle method, sulfate, polystyrene sulfate and decomposition method in order to remove the reaction product and excess salt, which method is US Patent No. 2,618,556, 3,247,969. 4,334,012, 4,758,505.

After washing with water, the emulsion is added with gelatin and subjected to reduction and chemical sensitization to increase sensitivity. For example, the reduction sensitization uses hydrazines, ascorbic acid and chiurea dioxide, which are disclosed in US Pat. Nos. 2,487,850, 2,518,698, 3,189,458 and 3,656,955, and the sensitization of chemical sensitization is Sodium thiosulfate, thiourea, and the like are disclosed in US Pat. Nos. 2,440,206, 2,728,668, 3,189,458, and 3,656,955 and the like.

In addition, in the present invention, the photosensitive silver halide is exposed to light using a wavelength of 580 to 710 nm in the laser emission wavelength range for scanning with a near-infrared laser to image the film. It is added in an amount of 0.01 to 0.5% by weight relative to the total weight.

At this time, when the amount of the sensitizing dye is less than 0.01% by weight, there is almost no effect of addition, and when it exceeds 0.5% by weight, fog tends to be produced.

The sensitizing dye may be a quinoline-benzothiazol-based or a mixture thereof, and such compounds are disclosed in US Pat. Nos. 2,912,343, 3,469,987 and 4,500,626.

According to the present invention, fog inhibitors and stabilizers are used to prevent fog generation during chemical increase and dye increase and decrease of sensitivity and stabilization during storage. For example, benzothiazol-based, nitorobenzene-based, imidazole-based, aziindorigin-based, and mercapto-based compounds are disclosed in US Pat. Is used and is disclosed in US Pat. Nos. 2,588,765, 2,964,404 and 3,121,060.

In addition, although a matting agent is used, starch, titanium dioxide, polymethyl methacrylate, silica, and the like are disclosed in US Patent Nos. 2,732,303, 3,288,775, and 4,678,735.

In the present invention, the thickener is used for the purpose of adjusting the viscosity in order to apply the photoemulsion agent and the protective agent to the polyester film to which the antihalation coating is applied in a thickness of 4 to 4.5 μm in a multi-layer at high speed.

Conventionally, thickeners such as thiol or polystarin have been used in US Pat. No. 3,936,401, but in the present invention, a cellulose ether-based was added to prepare a photo emulsion.

Examples of the cellulose ether type include cellulose 2-Hydroxypropyl methyl ether (hereinafter referred to as "HPMC") or cellulose 2-hydroxypropyl methyl ether phthalate acid ester (cellulose 2-hydroxypropyl methyl ether phthalate acid ester) (hereinafter referred to as "HPMCP").

The thickener is preferably used in the range of 1 to 5% by weight based on the photographic emulsion and the protective agent, respectively, in terms of viscosity control.

The photoemulsions thus prepared are multi-layered and dried using a method described in US Pat. No. 2,681,294 and Mroderm Coating and Drying Technology (1993 by Edgar Gattoff, VCH) with a protective layer on the backside coated with antihalation.

As described above, the photosensitive photosensitive material for printing plates manufactured by the method of the present invention has a bluish dots and spectral absorption wavelengths of bluish green color having high sensitivity, high resolution, and high contrast with fine grain crystals as before, as shown in FIG. A photo emulsion having a photographic characteristic may be prepared, and a thickening agent of the present invention may be added, followed by coating and drying to produce a film for printing of a He-Ne scanner.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the scope of the present invention is not limited to the following Examples.

Example 1

Photo emulsion manufacturing process

A solution was added 0.068 M of sodium chloride and 3 ml of 10% citric acid solution in 1,000 ml containing 2% by weight of bone gelatin, and 0.74 gM of sodium chloride in 400 ml of distilled water kept at 42 ° C. with stirring at pH 4.6 and 56 ° C., bromine A solution of potassium 0.185M, potassium hexadidium chloride 4 × 10 ^-6 M, 2 × ^10-6 M of hexadium potassium hexachloride, and 410 ml of distilled water maintained at 42 ° C. Inject 42 minutes to maintain the double injection method to lower the temperature to 32 ℃. 120 ml of 20% by weight sodium sulfate and 100 ml of 10% by weight magnesium sulfate are added, precipitated, and the supernatant is removed. 120 ml of 10% by weight of magnesium sulfate is added to 120 ml of the aggregated photographic emulsion, dispersed and precipitated to remove the supernatant and washed with water.

Such a photographic emulsion has a particle size distribution of 0.2 ~ 0.25㎛ as shown in Figure 1 to prepare a square AgBrCl containing 80 mol% of silver chloride. The pH was adjusted to 6.2 by adding 1,500 ml of bone gelatin 5.6 wt% solution to the photographic emulsion containing silver halide washed with water and adjusted to pH 6.2, 10 wt% of sodium chloride, 1 wt% of potassium iodide, and potassium thiocyanate 1.6 × 10 ^-2 M Sodium thiosulfate 1.23 × 10 ^-4 M, 1% by weight of 4-hydroxy-6-methyl 1,3,3a, 7-triazine-dorizine solution 20ml and 0.1% by weight of the sensitizing dye (Pina) As described above, 4.5 ml of each of the above-mentioned ingredients was aged until the maximum photographic properties were obtained.

1wt% 4-hydrooxy-6-methyl 1,3,3a, 7triazinedoridine 40ml

26 ml of 0.2wt% 1-phenyl-5-mercaptotetrazine

5wt% polyacrylic sulfate 20ml

10 ml of 5wt% modified hydroquinone

30 ml of 1wt% polyethylene olester (98)

5wt% Saponing 100ml

15 ml of 2wt% ethylene glycol

5 to 10 ml of 10wt% polymethylmethacrylate solution

5wt% H-AII 30ml

5wt% dodecyl sulfate sodium 20ml

10 ml of 20wt% glycerin

Photograph Characteristics According to Incremental Color Pigment Pigment mg / Ag mol Absorption wavelength (nm) Insensitivity Concentration Contrast Fog 668 16 650-710 90 4.5 4.2 0.05 559688 616 580-710 110 6.0 5.5 0.05 693890 1010 560-630 100 5.8 5.2 0.04 559693688 6610 600-710 120 6.2 5.8 0.04 559688627 6105 580-720 120 6.3 5.6 0.05 641844 1010 570-700 100 6.0 5.4 0.05 693699 1010 560-710 100 6.0 5.3 0.05

Example 2

HPMC or HPMCP, which is a thickener of the present invention, is added to the photo-emulsion agent and the protective agent obtained in Example 1 as shown in Table 2 and Table 3 below. The film for laser scanner printing plate was manufactured by carrying out a multilayer coating process and a drying process simultaneously with a photo emulsion and a protective agent by the extrusion coating method.

Photo emulsion viscosity (Cps) according to the amount of HPMC and HPMCP added Photo emulsion (%) HPMC 4wt% addition amount (ml) HPMCP 4wt% addition amount (ml) Viscosity (Cps) 3.5 -2030405060 6811141821 2030405060 1014172023 10152025 10152025 10141824 4.5 -1020304050 6810131620 1020304050 912161922 5101520 5101520 8121521

Protective agent viscosity (Cps) with HPMC and HPMCP addition Protective agent (%) HPMC 3wt% addition amount (ml) HPMCP 3wt% addition amount (ml) Viscosity (Cps) 2.5 -10203040 4681216 10203040 8121620 5101520 5101520 7111518 3.5 -351015 5681216 351015 7101418 1.52.55.07.5 1.52.55.07.5 791317

As described above, the photosensitive photosensitive material prepared according to the present invention is capable of applying a photoemulsion agent and a protective agent having a photographic property of high contrast, high resolution having finer crystals and spectral sensitivity of near infrared rays (630 μm and 680 μm). When a thickening agent for adjusting the viscosity is added, evenly applied and dried, a photosensitive material for a laser beam scanner printing plate film can be prepared.

Claims (4)

In the method for producing a film for laser scanner printing plate making, The mixture of acid solution containing gelatin, chloride, bromine, rhodium salt and iridium salt in the temperature range of 45 ~ 60 ℃ was mixed with silver nitrate solution by pAg 7.3 and mixed by double injection method. Square particles having a particle size of more than 80 mol% of silver bromide (AgBrCl) having a particle size of 0.2 to 0.25 μm or more and 90% or more of homogeneous particles were prepared, and then washed with water, chemical sensitization and sensitizing dye. After preparing a photo emulsion having a wavelength of 580 ~ 710㎛, and after the additive is added, a cellulose ether-based thickener is added to the back of the polyester film support coated with an antihalathion, with a protective layer and characterized in that it is dried Manufacturing method of film for laser scanner printing plate making. The method of claim 1, wherein the cellulose ester-based thickener is cellulose 2-hydroxypropyl methyl ether or cellulose 2-hydroxypropyl methyl ether phthalate acid ester, and the amount of the cellulose ester-based thickener is 1 to 5, respectively, for the photo emulsion and the protective agent. Manufacturing method characterized in that the weight%. The method according to claim 1, wherein the film is used interchangeably in each device of 630 mu m and 680 mu m of the He-Ne laser light source generator. The method of claim 1, wherein the sensitizing dye is quinoline-based, benzothiazol-based or a mixture thereof, and the amount of the dye is 0.01 to 0.5% by weight based on the photographic emulsion.