JPS5835539A - Method for making negative lithographic plate requiring no dampening water - Google Patents

Abstract

PURPOSE:To provide a plate-making method high in developing speed and little affected by humidity, by using a mixed soln. consisting of specified proportions of hydrocarbon, polar solvent, and water, and removing the exposed part of a silicone rubber layer. CONSTITUTION:A photopeelable photosensitive layer is formed on a support, and on this layer a silicone rubber layer is laminated to make a negative type lithographic plate requiring no dampening water. This layer is exposed and only the exposed part of the silicone rubber layer is removed by using a mixed soln. consisting of 0-97% hydrocarbon, 2-99% polar solvent, and 0.1-30% water. For said hydrocarbon, aliphatic hydrocarbons such as pentane, hexane, gasoline, kerocene, or the like are used, and for said polar solvent, for example, alcohols, ethers, esters, ketones, etc. are used.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for making a negative planographic printing plate that does not require dampening water, and particularly to a method for making a plate characterized by using a novel developer.

A lithographic printing plate that does not require dampening water and has a silicone rubber layer as an ink repellent layer, and is a plate material that works in a negative tone. The pre-sensitized product is 2%.
871.

These plate materials are usually plate-made by an exposure-development process at the same time as the PS plate, and a developer containing mainly a combination of an aliphatic hydrocarbon and a polar solvent is used. A sharp image can be formed on the printing plate using such a solvent-mixed developer, but the developing speed is slow and if the developing operation is insufficient, a silicone rubber layer may remain in one image area. , resulting in a printing plate with poor reproducibility of minute halftone dots.

A developing operation using such a developer has the disadvantage that it is susceptible to the influence of humidity during development.

The present invention overcomes these drawbacks and has a high development speed.
We provide all types of developers that are less affected by humidity.

The present invention provides a photoreleasable photosensitive 97 film provided on a support,
(B) polar solvents 2-99% and O) water 0.1-gO
The present invention relates to a plate-making method for a negative-working lithographic printing plate that does not require dampening water and is characterized in that substantially only the silicone rubber layer in the exposed portion is removed using a mixed solution of 4%.

The hydrocarbons used as the developer in the present invention include those capable of swelling silicone rubber, such as aliphatic hydrocarbons (pentane, hexane, heptane, octane or gasoline).

Kerosene, light oil, 9 heavy oil, etc.) can be conveniently applied.

Gasoline and kerosene are used at general printing work sites.

It is routinely used to wash away ink from printing presses and printing plates, and there is no objection to its use as a developer. In addition, aromatic hydrocarbons (toluene, xylene, etc.) or non-logenated hydrocarbons (triclene,
Of course, carbon tetrachloride, etc.) can also be used. The content of hydrocarbons in the developer is 0 to 97% by weight.

As polar solvents, those shown below are generally useful.

Alcohols (methanol, ethanol, n-globanol, impropatol, 5-methoxybutanol, 5
-Methyl-5-methoxybutanol, diacetone alcohol).

Ethers (dioxane, tetrahydrofuran.

Methyl cellosolve, ethyl cellosolve, butyl cellosolve, ethylene glycol diethyl ether.

Diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol diethyl ether, diethylene glycol monobutylated ether, triethylene glycol monomethyl ether,
triethylene glycol dimethyl ether, tetraethylene glycol monomethyl ether, tetraethylene glycol dimethyl ether, propylene gelicol monomethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, tetrahydrofurfuryl alcohol, etc.).

Esters (methyl acetoate, ethyl acetoate, methyl cellosolve acetate, ethyl cellosolve acetate, diethylene glycol monoethyl acetate, diethylene glycol monoethyl acetate, diethylene glycol motuptyl ether acetate, glycol diacetate, ethyl lactate, methyl propionate) , propion enemy ethyl.

dimethyl malonate, diethyl malonate, dimethyl co//acid, diethyl succinate, dimethyl adipate, etc.).

Ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, acetonylacetone, etc.).

2 to 99% by weight of at least one of the above polar solvents
It is preferable to use it in

The developer of the present invention is constituted by adding water in an amount of 0.1 to 50% by weight, preferably 1 to 15% by weight, to the above developer solvent or mixed solution. Also, emulsions made with a suitable emulsifier or dyes added can also be used.

What is the photoacidic photosensitive layer used in the present invention?
156871.

That is, the photofoamable photosensitive layer is one in which the silicone rubber layer thereon is removed by development without substantially removing the exposed portion of the photosensitive layer.

Such a light-peeling photosensitive layer can be produced by crosslinking a known pre-solubilization type photosensitive compound with a polyfunctional compound, or by bonding an active group in the pre-solubilization type photosensitive compound with a monofunctional compound. It can be obtained by modifying the resin to make it poorly soluble or insoluble in a developer.

The pre-solubilization type photosensitive compound mentioned here is:

Quinone diazides, which are usually used in positive P8 plates, Wibon plates, photoresists, etc.9 For example, esters of benzoquinone-1,2-diazide sulfonic acid and polyhydroxyphenyl, naphthoquinone-1,2-diazide sulfonic acid, etc. Ester with pyrogallol acetone resin, 7
Ester of toquinone-1,2-diazide sulfonic acid and phenol formaldehyde novolac resin, or complex of diazo compound with inorganic acid or organic acid.

An example is a photosensitive complex of diazodiphenylamine and phosphotungstic acid.

As a method for introducing a crosslinked structure into such a pre-solubilized photosensitive compound, there is a method in which reactive groups 1 such as hydroxyl groups and amine groups of the photosensitive compound are crosslinked with a polyfunctional crosslinking agent. .

As a crosslinking agent, 9 examples of polyfunctional isocyanates include EVA, paraphenylene diyne cyanate, 2.4- or 2.6-
-) luene diisocyanate, 4,4-diphenylmethane diisocyanate, hexamethylene diisocyanate, inphorone diisocyanate, or adducts thereof, or polyfunctional epoxy compounds 9 such as polyethylene glycol diglycidyl ethers, Examples include polypropylene glycol diglycidyl ethers, bisphenol A diglycidyl ether, and trimethylolpropane triglycidyl ether. Range 1 Normally 160 without losing the photosensitivity of these thermosetting recreational photosensitive materials
It is necessary to carry out the process at a temperature below 0.degree. C., and for this purpose, a catalyst or the like is used in combination.

In addition, as a method for introducing a component that is refractory or insoluble in a developer into a pre-solubilized photosensitive compound, it is possible to similarly esterify, amidate, or urethanize the active group of the photosensitive compound. Agera pull, ru. Even if the compound to be reacted with the active group of the photosensitive compound is a low molecule,
It may be a relatively high molecular weight material, or a photosensitive compound may be subjected to craft polymerization of a monomer.

Particularly preferable photosensitive layers for use in the present invention are:
It is obtained by crosslinking or modifying a partially esterified product of naphthoquinone-1,2-diazide-5-sulfo/acid and phenol formaldehyde novolak resin with a polyfunctional or monofunctional incyanate.

The appropriate thickness of the photosensitive layer is approximately 0.1 to 100μ, preferably approximately 0.5 to 10μ; if it is too thin, defects such as pinholes may easily occur during coating. Too much is disadvantageous from an economic standpoint.

In addition, other components may be added to the photosensitive layer for the purpose of improving coating film formation properties and adhesion to the support within a range that does not impair the effects of the present invention, and may also be used to visualize images during development or exposure. It is possible to add dyes etc. for this reason.

The silicone rubber layer used in the present invention contains a linear organic polysiloxane with a molecular weight of several thousand to several hundred thousand having repeating units of 9th order as a product.

Here, n is an integer of 1 or more, R is an alkyl group, alkenyl group, or phenyl group having 1 to 10 carbon atoms, and R is 6
Preferably, 0% or more is methyl group. Such a linear organic polysiloxane can be sparsely crosslinked to form a silicone rubber by adding an organic peroxide and subjecting it to heat treatment.

A crosslinking agent is also added to the linear organopolysiloxane. Examples of crosslinking agents used in so-called room temperature (low temperature) curing silicone rubber include acetoxysilane, ketoxime silane, alkoxysilane, aminosilane, and amidosilane. When combined with other substances, they become deacetic acid type, oxime type, dealcoholized type, deamined type, and deamidated type silicone rubber, respectively. Generally, a small amount of an organic tin compound or the like is further added as a catalyst to these silicone rubbers.

The appropriate thickness of the silicone rubber layer is approximately 0.5 to 100μ, preferably approximately 0.5 to 10μ; if it is too thin, problems may occur in terms of printing durability; - If the blade is too thick This is not only economically disadvantageous, but also makes it difficult to remove the silicone rubber layer during development, resulting in a decrease in image reproducibility.

In the lithographic printing plate of the present invention, a support and a photosensitive layer.

Adhesion between the photosensitive layer and the silicone rubber layer is extremely important for basic plate performance such as image reproducibility and printing durability, so an adhesive layer may be provided between each layer as necessary. It is possible to add adhesion improving ingredients to each layer. In particular, for adhesion between the photosensitive layer and the silicone rubber layer, a known silicone primer or Sila 7 coupling agent layer is provided between each layer.

It is effective to add a siligene primer or a silane coupling agent to the silicone rubber layer or photosensitive layer.

The support must be flexible enough to be set in a normal lithographic printing machine and capable of withstanding the load applied during printing. Typical examples include metal plates such as aluminum, copper, and steel, plastic films such as polyethylene terenotalate, and coated paper. It is also possible to provide a support by further coating these sheets for antihalation purposes and other purposes.

A thin protective film can also be laminated on the surface of the silicone rubber layer forming the surface of the planographic printing plate that does not require dampening water and is constructed as described above.

As explained above, the lithographic printing plate which does not require dampening water and which is used in the present invention can be manufactured in the following manner. First, onto the support, use an ordinary coater such as a reverse roll coater, an air knife coater, a Meyer bar coater, or a rotary coating device such as a Whaler to coat the m-acid solution that constitutes the photosensitive layer, dry it, and apply as necessary. After heat curing, if necessary, apply an adhesive layer on the photosensitive layer in the same manner, and after drying, apply a silicone gum solution on the adhesive scraps in the same manner. Heat treatment is performed for several minutes to fully cure and form a silicone rubber layer. If necessary, apply a protective film to the silicone rubber 1-
Use a laminator etc. on top to make a par.

The lithographic printing plate manufactured in this way that does not require dampening water is 1
For example, it is exposed to actinic radiation through a vacuum-sealed negative film. The light sources used in this exposure process are those that produce abundant ultraviolet light, including mercury lamps, carbon arc lamps, and xenon lamps.

Metal halide lamps, fluorescent lamps, etc. can be used.

Next, the surface of the exposed plate was treated without using the developer of the present invention.
When rubbed with a developing pad, only the silicone rubber layer in the exposed area is removed, and the photosensitive layer, which is insoluble in the developer due to crosslinking and modification, remains without substantially reducing its thickness. death.

A negative planographic printing plate which does not require dampening water is provided, in which the exposed surface of the photosensitive layer becomes an ink receiving area.

By applying the developer of the present invention, a printing plate with stable developability, which has better reproducibility of minute halftone dots in a shorter development time than before, and is significantly less affected by humidity during development. is obtained.

The present invention will be described in detail below with reference to Examples.

Example 1. Comparative Example 1 (A) Made by Sumitomo Metals, chemically treated aluminum plate (thickness: 05 m)
IN+) was coated with the following photosensitive layer composition and heated at 120°C.
.

A photosensitive layer having a thickness of 2.6 μm was provided by heat treatment for 2 minutes.

(a) 100 parts of naphthoquinone-1,2-diazide-5-sulfonic acid ester of phenol novolac resin (Sumilight Resin PR50255, manufactured by Sumitomo Durens) with a degree of esterification of 44% (b)
4.4'-diphenylmethane diisocyanate
20 parts ←) Dibutyltin dilaurate 0.2 parts (cl) Methyl cellosolve acetate 2000 parts Next, a silicone rubber composition of the following composition was spin-coated thereon, and heated and cured at 120°C for 2 minutes to a thickness of 2.2μ. A silicone rubber layer was provided.

(a) Dimethylpolysiloxane (molecular weight approximately so, o
oo terminal hydroxyl group) 100 parts (1)) Ethyltriacetoxysilane 5 parts (Q) Dibutyltin diacetate 02 parts (d) γ-aminopropyltriethoxysilane
3 parts (θ) Isopar 1 1
650 copies Negative film (150 lines, 1% to 9%
9%) was vacuum-adhered and exposed for 50 seconds from a distance of 1 m using a 2 kW metal halide lamp.

Each of the exposed plates was developed using a developer shown in Table 1 to obtain a negative planographic printing plate that did not require dampening water. Table 1 shows the results regarding the time required to develop the printing plates obtained using these developers and the halftone reproduction area of the printing plates.

Ugliness that includes water 2. m4. m6. When using m8 developer,
Only the silicone rubber layer in the exposed areas was removed, and the halftone dot reproduction range was 1 to 98% or more in all cases. As a comparative example, I&11゜m5. without water. m5. When using the m7 developer, only the silicone layer in the exposed areas is removed, but the development time is long and the halftone dot reproducibility is insufficient. Furthermore, it is poisonous if it cannot be developed during dry periods such as winter.

Example 2. Comparative Example 2 Resole resin (Sumilight Resin PC-1, manufactured by Sumitomo Durez) on an aluminum plate (manufactured by Sumitomo Light Metal) with a thickness of 0.24 mm
was coated to a thickness of 2 μm and cured at 180° for 0.5 minutes to prepare a support. The following photosensitive layer composition was spin-coated onto this support and cured by heating at 120°C for 2 minutes to a thickness of 2.4 cm.
A photosensitive layer of μ was provided.

100 parts of sulfonic acid ester (from Example 1) (→ 2
．． 6-) Luene diisocyaner) 20 parts (C)
Dibutyltin dilaurate 0.2 part (d)
2000 parts of dioxane and γ-
Aminopropyltriethoxysilane (manufactured by Union Carbide, -A1100' 0.5 weight "Isopar E"
(manufactured by Esso) was spin-coated using a Whaler, and after being left for one day, a silicone rubber composition liquid having the composition shown below was spin-coated on top of the solution.

A silicone rubber layer of 2.1 μm was formed by heating and curing at 120° C. for 2 minutes.

(→ Dimethylpolysiloxane (molecular weight approx. so, ooo
, terminal hydroxyl group) 100 parts (b) Vinyltrimethylethylketoxime) Sila 7
8 parts (C) 0.2 parts of diptyltin diacetate (
ψ Isopar E IBoo part 150 in vacuum contact with the printing original plate obtained as above
A negative film having a line halftone image was exposed for 60 seconds from a distance of 1 m using a 2kw12 metal halide lamp. When the exposed plate is immersed in a conventionally used developer (Isopar E/Ethanol-55765) at a relative humidity of 35 to 80 degrees in the atmosphere during development, and the surface of the plate is lightly rubbed with a developing pad. Only the exposed silicone rubber layer is removed to expose the surface of the photosensitive layer, resulting in an image faithful to the original film. However, if the relative humidity of the atmosphere at the time of development is less than 35%, the development speed will be extremely low, making it impossible to faithfully reproduce the image, resulting in poor development.

Further, when the humidity is 80% or more, the developing speed becomes extremely high and the developing performance is not constant. However, when 3 parts of water is added to this developer, the developability is always constant without being affected by the humidity during development, and workability is improved. In addition, a stable printing plate was always obtained with a halftone dot reproduction area of 150 lines and 99% per chill.

Patent applicant: Toshi Co., Ltd.

Claims (1)

[Claims] (1) A photoreleasable photosensitive layer provided on a support. A negative-working lithographic printing plate that does not require dampening water and is characterized in that substantially only the silicone rubber layer in the exposed area is removed using a liquid mixture consisting of a silicone rubber layer on top of the silicone rubber layer that does not require dampening water. Plate making method.