JPH04318551A - Planographic printing plate material - Google Patents

Abstract

PURPOSE:To improve the ink detaching speed of a planographic printing plate provided with an ink detaching property of the surface of a hydrophilic binder layer and to obviate the staining of non-image parts with ink by incorporating a specific nonionic surfactant into the above printing plate material. CONSTITUTION:The nonionic surfactant having HLB (Hydro-phile-lipophile- balance)=6 to 14 into the plate making material formed by using a silver halide emulsion is contained. The more specific examples of this surfactant include the combination use of sorbitan monopermitate, sorbitan monolaurate, polyoxyethylene, sorbitan monooleate, etc. The hydrophilic binder forming the ink and generation surface layer is exemplified by gelatin, acylated gelatin, graft gelatin, etc. Preferable results are obtd. when this material is applied to the planographic printing material having the roughened hydrophilic binder surface.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to lithographic printing plate materials, and in particular, a nonionic surfactant having an HLB of 6 to 14 is added to the plate making material to impart high water retention to the non-image areas of the plate surface. The present invention relates to a lithographic printing plate material characterized in that the present invention is coated with a lithographic printing plate material.

0002

2. Description of the Related Art A lithographic printing plate consists of a lipophilic image area that accepts ink and a hydrophilic non-image area that does not accept ink, and generally the non-image area accepts water. Therefore, in normal lithographic printing, both ink and water are supplied to the plate surface, and the ink is selectively received in the image areas and the water is selectively received in the non-image areas, and the ink on the image lines is transferred to the paper. It will be done. Therefore, in order to obtain good printed matter, the difference in lipophilicity and hydrophilicity between the surface of the printed area and the non-printed area must be sufficiently large so that when water-ink in an emulsified state comes, the printed area It is necessary to receive enough ink, and the non-image area must receive enough water. The lithographic printing plates related to the present invention are also printed based on the same principle.

One of the lithographic printing materials related to the present invention is a lithographic printing plate to which a silver complex diffusion transfer method is applied. This printing plate material has silver precipitate nuclei in the hydrophilic polymer binder layer or on its surface, a silver image is formed on the silver precipitate nuclei by silver complex salt diffusion transfer treatment, and the silver image is made ink receptive. The surface of the hydrophilic binder in the non-image area is made ink repellent and can be used for printing. Although the surface of the hydrophilic binder is hydrophilic in itself, it has poor water retention and extremely poor repellency to printing ink, so the ink stains in non-image areas due to printing are significant, making it impractical for practical use. It is known that a method of improving the ink repellency of this type of binder surface is to roughen the surface by dispersing fine powder such as silica or starch in the binder layer and impart water retention properties. There is. However, the ink repellency obtained by these methods is still insufficient, and when printing is performed by supplying ink and water, ink stains occur in non-image areas of printed matter. This phenomenon becomes more noticeable as the number of printed sheets increases.

0004

SUMMARY OF THE INVENTION An object of the present invention is to improve the ink removal speed of a lithographic printing plate in which the surface of a hydrophilic binder layer is made ink removable, and to improve ink stains in non-image areas. Our goal is to provide printing plate materials. The ink removal speed referred to here refers to the speed from the state in which ink is applied to the entire surface of the lithographic printing plate without dampening water until the ink is removed from the non-image area of the plate after the dampening water is started. means. This is because it is possible to reduce paper waste by improving the ink-water response on the plate surface, such as during initial ink build-up during printing or recovery from accidental staining of non-image areas. is important.

[0005]

[Means for Solving the Problems] In a lithographic printing plate material having a hydrophilic binder layer surface with ink releasability, HLB
This is achieved by containing a nonionic surfactant in the range of =6 to 14. Further, the present invention can not only improve the stain resistance of non-image areas of printed matter, but also simultaneously improve water retention and ink removal speed. INDUSTRIAL APPLICATION This invention is suitable for the lithographic printing plate which makes a silver image receptive to ink, and especially the lithographic printing plate material which makes a silver image formed on the silver precipitation nucleus by the silver complex salt diffusion transfer method ink receptive.

[0006] Surfactants are generally used as wetting agents to improve wetting when forming a hydrophilic polymer binder layer on a suitable strip-shaped substrate.
Surfactants outside of the above range do not have the effect of the present invention and cannot prevent ink stains in non-image areas due to printing. Surfactants can be broadly classified into anionic, cationic, nonionic,
Although there are amphoteric surfactants other than betaine, nonionic surfactants are basically preferred in the present invention.

Next, specific examples of surfactants used in the present invention will be listed, but the present invention is not limited thereto, and two or more of these surfactants may be used in combination. Among the surfactants, the following surfactants have HLB = 6 to 14
within the range of (1) Sorbitan monopalmitate
[HLB=6.7] (2) Sorbitan monolaurate [HLB=8
．． 6] (3) Combination of polyoxyethylene and sorbitan monooleate [HLB=9.6] (4) Combination of polyoxyethylene and sorbitol tetraoleate [HLB=11.8] (5) Polyethylene glycol, monooleate Combined use of rate [HLB=13.7]

[0008] As a comparison of the activators used in the present invention,
The following activators are listed: (1) Sorbitan triolate [HLB=1.8] (
2) Sorbitan sesquiolate [HLB=3.7] (
3) Sorbitan monostearate [HLB=4.7]
(4) Combination of polyoxyethylene and sorbitan monostearate [HLB=14.9] (5) Combination of polyoxyethylene and sorbitan monooleate [HLB=15.0] (6) Polyoxyethylene and sorbitan monostearate Combined use of laurate [HLB=16.7] (7) Combined use of polyethylene glycol and monostearate [HLB=19.1] These surfactants are known and available as commercial products.

Hydrophilic binders forming the ink-repellent surface layer used in the present invention include gelatin, acylated gelatin, grafted gelatin, polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl acrylamide, carboxymethyl cellulose, hydroxymethyl cellulose, polyvinyl Methyl ether, methyl vinyl ether
Maleic anhydride copolymer, styrene/maleic anhydride copolymer, isobutylene/maleic anhydride copolymer, condensate of polyvinyl alcohol and styrene maleic anhydride copolymer, polyvinyl alcohol and isobutylene/maleic anhydride copolymer Condensate of coalescence, gum arabic, albumin, sodium alginate, cellulose sulfate, JP-A-53-2160
Various natural or synthetic polymers such as the polyfunctional synthetic polymer described in Publication No. 2 can be used alone or in combination of two or more. This ink-repellent surface layer contains a hydrophilic binder and a silver halide emulsion such as silver chloride, silver bromide, silver chlorobromide, silver iodobromide, silver chloroiodobromide, gold, silver, copper, platinum, etc. Heavy metals such as palladium and zinc or silver precipitation nuclei such as their sulfide colloids, hydroquinone, 1-phenyl-3
- May contain a developing agent such as pyrazolidone. The composition forming the layer adjacent to the surface layer in the present invention is the same as that of the surface layer and will not be described here, but in reality, it may be the same or different. Further, in the present invention, there is no need for a layer adjacent to the surface layer to exist. In order to give the above surface layer and its surface layer sufficient mechanical strength as a printing plate, hardening agents of the hydrophilic binder contained therein include formalin, glyoxal, glutaraldehyde, tannic acid, dimethylol urea, and ethylene. Organic compounds such as urea resins and mucohalogen acids (mucochloric acid, mucobromic acid), and inorganic compounds such as chromium alum and potassium alum are used as necessary.

As mentioned above, when the present invention is applied to a lithographic printing plate material having a roughened hydrophilic binder surface,
The most preferable results can be obtained, but methods for forming the roughened surface include a method using a support having a roughened surface, a method of molding the surface of the hydrophilic binder layer using a roughened roll, etc. There are a method of containing fine particle powder on the surface of the binder layer and a method of combining these methods. A suitable combination of these provides more favorable results in the present invention. For example, an embodiment in which a hydrophilic binder layer containing fine particle powder is provided on a support having a roughened hydrophobic resin surface is a typical preferred embodiment of the present invention. The support having a hydrophobic surface can be roughened by a solvent processing method, a foaming method, a pressure bonding method using a rough surface, or the like. These rough surfaces preferably have a depth of 2 to 20 microns and a size of approximately 10 to 100 microns. "Depth" here refers to the distance from the valley of the uneven surface to the top of the mountain, and "size" refers to the distance from mountain to mountain. Examples of fine particle powders include silica, talc, clay, titanium oxide, barium sulfate, zinc oxide, rice starch, etc., and have an average particle size of about 0.8 to 15 μm.
Preferably.

Various supports for the lithographic printing plate material of the present invention include synthetic resin films such as polyethylene terephthalate, polycarbonate, polypropylene, and polystyrene, polyolefin-coated paper, polyolefin laminated films, and aluminum-reinforced composite supports. can be used.

[0012] The printing plate obtained using the lithographic printing plate material of the present invention has ink repellency to the processing liquid for desensitization treatment that is carried out as necessary during printing, and also to the dampening water etc. supplied during printing. Colloidal particles such as silica and alumina, and polyol compounds such as ethylene glycol, diethylene glycol, α-propylene glycol, and glycerin can be included for the purpose of assisting the water retention property of the surface.

The lithographic printing plates according to the present invention include direct-drawing type lithographic printing plates, lithographic printing plates whose silver image is ink receptive by applying the silver complex diffusion transfer method, and image-exposed materials coated with silver halide emulsions. - A type of lithographic printing plate in which the silver halide image portion after development is made lipophilic to make it ink receptive, and the surface of the hydrophilic binder-containing layer is made to be ink repellent and can be used for printing. Although not limited thereto, a lithographic printing plate in which an ink-receptive silver image is produced by applying a silver complex diffusion transfer method is particularly suitable.

[0014] Furthermore, the surfactant used in the present invention is
It can be used anywhere in the lithographic printing plate. In particular, in a lithographic printing plate in which a silver image is ink receptive by applying a silver complex salt diffusion transfer method, it can be used in any of the antihalation layer, emulsion layer, and physical development nucleus layer.

[0015] Further, the appropriate amount of surfactant used in the present invention is such that the layer-forming coating liquid has a moisture content in the range of 1% to 0.01% to improve the ink removal rate and to prevent scumming. Demonstrates the effectiveness of prevention.

Next, typical embodiments of the present invention will be described, but the present invention is not limited thereto.

[0017]

【Example】

Examples 1 to 5, Comparative Examples 1 to 7 The rough surface of a double-sided polyethylene-coated paper support having a roughened surface with an average depth of 7μ and an average size of 50μ was made hydrophilic by corona discharge. After the surface treatment, a liquid having the following composition was applied so that the moisture content was 30 g/m2. gelatin
20g silica (average particle size 7μ)
5 g formalin (12% aqueous solution) 3 ml carbon black dispersion (solid content 32%) 3 ml saponin (10% aqueous solution) 10 ml water to bring the total amount to 600 g.

On top of this, an ortho-sensitized high-sensitivity silver halide emulsion having the following composition was coated with different types of surfactants as shown in Table 1 at a moisture content of 30 g/m2. . Silver halide emulsion (25g silver nitrate, 2g gelatin)
Silver chlorobromide emulsion prepared using 0g) 60g
Silica (average particle size 7μ)
1g formalin (
12% aqueous solution)
3ml surfactant (10% solution)...
A 10ml
Add water to bring the total amount to 600g.

Furthermore, palladium sulfide (silver precipitation nuclei) sol prepared by the following method was applied thereon at a speed of 5 m/min. A liquid palladium chloride
5g hydrochloric acid
40ml water

1000ml B liquid sodium sulfide
8.6g water
1000ml C liquid Methyl vinyl ether/maleic anhydride copolymer (
1.25% solution)

100ml saponin (10% aqueous solution)
200ml water
18000ml

0020A
The liquid and the liquid B were mixed with stirring, and after 30 minutes, the mixture was purified by passing through a column containing an ion exchange resin, and liquid C was added thereto to obtain a coating liquid.

The lithographic printing plate material thus obtained was subjected to image exposure using a camera having an image reversal mechanism, and developed at 30° C. for 30 seconds using a silver complex diffusion transfer developer having the following composition. Ta. Sodium hydroxide
20g anhydrous sodium sulfite
100g hydroquinone
12g 1-phenyl-3-
Pyrazolidone
1g sodium thiosulfate
16
g potassium bromide
3
g 1-ethyl-2-mercaptobenzimidazole 0.05g 3-mercapto-4-acetamido-5-n-heptyl-1,2,4-triazole

Add 0.1 g of water to make the total volume 2000 ml.

After the development process, the developer is removed from the printing plate material using a squeezing roller, and a neutralizing solution having the following composition is used to remove the developer.
It was treated at ℃ for 20 seconds, the liquid was removed with a squeezing roller, and it was dried. Colloidal silica (20% solution)
1g citric acid
10
g Sodium citrate
Add 35g water to make the total volume 100%
Make it 0ml.

[0023]

[Table 1]

The lithographic printing plate prepared by the above procedure was mounted on an offset printing machine, and after the plate surface was treated with a desensitizing liquid, printing was immediately performed. The following procedure was then followed. 1. Normal printing 2. Stop feeding the dampening water so that the ink covers the entire surface of the plate. 3. Start feeding the dampening water again. 4. After that, print normally.

The number of printed sheets when the ink was detached from the printing plate was defined as the number of ink detached pages, and this value was used to express the difficulty of ink detachment and the degree of ink staining. The desorption of the ink from the printing plate was observed by measuring the density of the printed material using a densitometer.

Example 6 The same roughened support surface as that used in Examples 1 to 5 was subjected to corona discharge machining, and then a coating liquid having the following composition was applied at a moisture content of 40 g/m2. I applied it to make it look like this. gelatin
20g silica (average particle size 7μ)
5g formalin (12% aqueous solution)
3ml sorbitan monopalmitate (10% solution)
Add 4 ml of water to bring the total amount to 500 g.

Next, a hydrosol composition of silver precipitation nuclei obtained by mixing the following solutions A and B was applied at a moisture content of 15 g/m 2 . A liquid palladium chloride
1g hydrochloric acid
20ml water
250ml B solution sodium thiosulfate
4g saponin (10% aqueous solution) 10m
l water
1000ml

The lithographic printing plate thus obtained was brought into close contact with a negative material for silver complex diffusion transfer that had been image-exposed in advance, and the same photographic and printing processes as in the examples were carried out to print. , no ink stains occurred. Furthermore, when a surfactant outside the HLB range of 6 to 14 was used, light ink stains occurred on the entire surface of the printed matter.

[0029]

Effect of the invention: Figure 1 shows the HLB of each surfactant used.
The relationship between the value and the number of sheets from which ink is removed from the hydrophilic binder film is shown. From Figure 1, those in the range of HLB = 6 to 14 are:
The ink was difficult to adhere to the surface of the hydrophilic binder, and the ink removal rate was fast. Furthermore, the ink did not detach from the surface of the hydrophilic binder to which no surfactant was added. In addition, in addition to the lithographic printing plate material that makes the silver image ink receptive by applying the silver complex diffusion transfer method, the non-image area can be similarly reduced even if the nonionic surfactant with HLB = 6 to 14 used in this study is used. The results showed that the ink removal rate was improved.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the relationship between the HLB value of each surfactant and the number of sheets of hydrophilic binder film from which ink is removed.

Claims (1)

[Claims] Claim 1: In a plate-making material using a silver halide emulsion, HLB (Hydro-phile-lipop)
A lithographic printing plate material containing a nonionic surfactant having a heel balance of 6 to 14.