JPH09222737A - Positive type photosensitive planographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a planographic printing plate excellent in printing resistance and development latitude. SOLUTION: A layer (A) contg. alkali-soluble novolak resin and a positive type photosensitive compd. is formed on a substrate and a layer (B) contg. a high molecular compd. insoluble in water but soluble in an alkaline aq. soln., preferably a high molecular acrylic or urethane compd. is formed under the layer A when the layer B has higher solubility to the alkaline aq. soln. than the layer A and on the layer A as the layer (C) when the layer B has lower solubility than the layer A.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive-working photosensitive lithographic printing plate, and more specifically, it has a photosensitive layer using a water-insoluble polymer compound soluble in an alkaline aqueous solution and an alkali-soluble novolac resin. The present invention relates to a positive photosensitive lithographic printing plate.

[0002]

2. Description of the Related Art Conventionally known positive-working photosensitive lithographic printing plates are
A novolac type phenol / cresol resin was used as a binder. Due to the nature of the novolac resin, this lithographic printing plate has a brittle coating and is inferior in abrasion resistance, and therefore has insufficient printing durability. Furthermore, the printing durability is extremely insufficient under printing conditions where the chemical resistance is poor and plate cleaners are frequently used, and when UV ink is used.

In order to solve these problems, the addition of various polymer compounds as a binder has been studied. For example, Japanese Examined Patent Publication No. 52-28401 and Japanese Patent Laid-Open No. 29124/1989.
No. 4, JP-A-2-866 and the like have proposed polymer compounds.

However, since the above-mentioned binder does not sufficiently interact with the positive-working photosensitive compound,
The tolerance (so-called development latitude) for variations in time and temperature during development and variations in developer concentration is narrow.
Therefore, when these binders are added, there is a problem that the printing latitude and chemical resistance are improved, but the development latitude is deteriorated.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a positive-working photosensitive lithographic printing plate which is excellent in both printing durability and development latitude, and particularly under printing conditions where a plate cleaner is frequently used. Another object of the present invention is to provide a positive photosensitive lithographic printing plate which has sufficient printing durability even when UV ink is used and is excellent in development latitude.

[0006]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventor has found a positive-working photosensitive lithographic printing plate in which the upper layer is more difficult to dissolve in an alkaline aqueous solution than the lower layer. Invented. That is, the present invention is specified by the following items (1) and (2). (1) A layer (A) containing an alkali-soluble novolac resin and a positive-working photosensitive compound is provided on a support, and a highly alkaline aqueous solution-soluble layer is provided between the layer (A) and the support. A positive photosensitive lithographic printing plate comprising a layer (B) containing a molecular compound and more easily dissolved in an alkaline aqueous solution than the layer (A). (2) A layer (A) containing an alkali-soluble novolac resin and a positive-working photosensitive compound is provided on a support, and an aqueous alkaline solution-soluble polymer compound is contained on the layer (A). A positive photosensitive lithographic printing plate provided with a layer (C) that is less soluble in an alkaline aqueous solution than the layer (A).

[0007]

Embodiments of the present invention will be described below in detail. The positive-working photosensitive lithographic printing plate of the present invention has, as a photosensitive layer, a layer (A) containing an alkali-soluble novolac resin and a positive-working photosensitive compound on a support, and is further water-insoluble and alkaline. It has a layer containing a polymer compound soluble in an aqueous solution. In this case, the solubility of the layer containing the polymer compound and the layer (A) in an alkaline aqueous solution is compared, and when the solubility of the layer containing the polymer compound is higher than that of the layer (A), the layer (A) is A layer (B) containing the above-mentioned polymer compound is provided as a lower layer between the layer (A) and the support, and when the solubility in the alkaline aqueous solution is lower than that of the layer (A), the upper layer of the layer (A) On the layer (A), a layer (C) containing the polymer compound is provided.

Thus, the photosensitive layer comprises a layer (A) mainly composed of an alkali-soluble novolak resin and a positive-working photosensitive compound, and a layer mainly composed of a polymer compound insoluble in water and soluble in an alkaline aqueous solution ( Separation into B) or (C) effectively develops a wide development latitude and high printing durability and chemical resistance, and positive type photosensitivity excellent in printing durability, chemical resistance and development latitude. A lithographic printing plate is obtained.

On the other hand, when the photosensitive layer having the composition of the layer (A) is provided without providing the layer (B) or (C), the printing durability and the chemical resistance are remarkably lowered, while the layer (A) is not provided.
If the photosensitive layer containing the positive-working photosensitive compound is provided in the layer (B) or (C) without providing the above, the development latitude will be insufficient. Layer (A)
If a photosensitive layer having a single-layered composition in which the components of both layers are mixed is provided without separating the layer and the layers (B) or (C), the printing durability and chemical resistance are higher than those obtained by separating both layers. And the development latitude is inferior.

In the present invention, the difficulty of dissolution of the layer in an alkaline aqueous solution is that the layer corresponding to the layer (A) and the layer containing the polymer compound (B) and the layer corresponding to the layer (C) are respectively made of polyethylene terephthalate ( Samples were prepared by applying the same coating amount as that of the layers in the lithographic printing plate on a PET) support, and dipping these samples in a 2.5 wt% aqueous solution of sodium silicate No. 3 (25 ° C.). The time required to complete the dissolution of the coating film is obtained and evaluated, and when the times differ by two times or more, it is considered that there is a significant difference. Therefore, the layer (A) and (B) or (C) in the present invention satisfy such a difference in solubility.

As described above, the stacking order of the layer (A) and the layer (B) or (C) is determined according to the solubility in an alkaline aqueous solution, and the layer having a low solubility is set as the upper layer, whereby excellent development latitude is obtained. Is obtained. On the other hand, when the stacking order is reversed, the development latitude is significantly deteriorated. Further, when the difference in solubility becomes small, the effect of improving the development latitude is reduced.

In the present invention, when the layer (A) and the layer (B) or (C) are laminated, the contact interface between the layer (A) and the layer (B) or the vicinity of the contact interface (the layer (A) and the layer (A) The components of both layers may be mixed in a portion corresponding to a thickness within 5% of the total thickness of (B) or (C).

In the positive-working photosensitive lithographic printing plate of the present invention, a layer (A) mainly composed of an alkali-soluble novolak resin and a positive-working photosensitive compound, and a polymer compound insoluble in water and soluble in an alkaline aqueous solution are mainly composed. Layer to be (B)
Alternatively, the ratio with (C) is arbitrary, but the weight ratio is 5 :.
The range of 95 to 95: 5 is preferable, and the range of 10:90 to 90:10 is particularly preferable.

When the ratio of the layer (A) to the layer (B) or (C) is within the above range, the printing durability, chemical resistance and development latitude will be excellent. On the other hand, when the ratio of the layer (A) becomes small, the development latitude becomes insufficient, and when the ratio of the layers (B) and (C) becomes small, the printing durability and the chemical resistance become insufficient.

The thickness of the photosensitive layer in the positive-working photosensitive lithographic printing plate of the present invention varies depending on the application, etc., but is usually expressed by the coating amount (solid content) and is generally 0.5 to 5.0 g / m ² . The thickness of each layer can be determined according to the above ratio.

The following mainly describes the case where the photosensitive layer, which is a preferred embodiment of the present invention, has a two-layer structure of the layer (A) and the layer (B) or (C).

The alkali-soluble novolac resin mainly used in the layer (A) in the present invention is, for example,
Phenol formaldehyde resin, m-cresol formaldehyde resin, p-cresol formaldehyde resin, m- / p-mixed cresol formaldehyde resin,
Examples thereof include alkali-soluble novolac resins such as phenol / cresol (m-, p-, or m- / p- mixture may be used) mixed formaldehyde resin.
These alkali-soluble novolak resins have a weight average molecular weight of 500 to 20,000 and a number average molecular weight of 200 to
10000 is used. Furthermore, US Pat.
No. 123279, such as t-butylphenol formaldehyde resin, octylphenol formaldehyde resin, having 3 to 8 carbon atoms.
You may use together the condensate of the phenol which has the alkyl group of this as a substituent, and formaldehyde.

In the present invention, the positive-working photosensitive compound mainly used in the layer (A) is specifically an o-naphthoquinone azide compound.

The o-naphthoquinone azide compound used in the present invention is preferably an ester of 1,2-diazonaphthoquinone sulfonic acid chloride and pyrogallol acetone resin described in JP-B-43-28403. . Other suitable orthoquinonediazide compounds are described in US Pat. Nos. 3,046,120 and 3,188,210, which are 1,2.
There are esters of diazonaphthoquinone sulfonic acid chloride with phenol-formaldehyde resins. Other useful o-naphthoquinone azide compounds have been reported and known in numerous patents. For example, JP-A-47-5303, JP-A-48-63802 and JP-A-48-6.
No. 3803, No. 48-96575, No. 49-3870.
No. 1, No. 48-13354, No. 37-18015,
No. 41-11222, No. 45-9610, No. 49-
17481, U.S. Pat. Nos. 2,797,213, and 345.
No. 4400, No. 3544323, No. 357391.
No. 7, No. 3674495, No. 3785825,
British Patent Nos. 12276602 and 1251345,
No. 1267005, No. 1329888, No. 1
Examples include those described in various publications such as 330932 and German Patent No. 854890 and each specification.

In the present invention, particularly preferred o-naphthoquinonediazide compound is a compound obtained by reacting a polyhydroxy compound having a molecular weight of 1000 or less with 1,2-diazonaphthoquinonesulfonic acid chloride. Specific examples of such compounds are described in JP-A Nos. 51-139402, 58-150948, 58-203434 and 5
9-165053, 60-21445, 60-
No. 134235, No. 60-163430, No. 61-1
No. 8744, No. 62-10645, No. 62-1064
No. 6, No. 62-153950, No. 62-178562.
JP-A-1-76047, JP-A-2-213847,
U.S. Pat. Nos. 3,102,809, 3,126,281, 313,0047, 3,148,983, and 31.
No. 84310, No. 3188210, No. 463640.
No. 6, etc., and those described in each specification can be mentioned.

When synthesizing these o-naphthoquinonediazide compounds, it is preferable to react 0.2-1.2 equivalents of 1,2-diazonaphthoquinonesulfonic acid chloride with the hydroxyl group of the polyhydroxy compound,
Furthermore, it is preferable to react 0.3 to 1.0 equivalent.

The resulting o-naphthoquinonediazide compound is a mixture of 1,2-diazonaphthoquinonesulfonic acid ester groups having different positions and introduced amounts, but all of the hydroxyl groups are 1,2-diazonaphthoquinonesulfonic acid ester. The ratio of the compound converted in (3) to the mixture (content of the completely esterified compound) is preferably 5 mol% or more, more preferably 20 to 99 mol%.

Further, as a photosensitive compound acting in a positive type without using an o-naphthoquinonediazide compound, for example, a polymer compound having an orthonitrocarbinol ester group described in Japanese Patent Publication No. 56-2696. Can also be used in the present invention.

Further, a compound capable of generating an acid by photolysis and a --C--O--C group or --C--O-- which is dissociated by the acid.
A combination system with a compound having a Si group can also be used in the present invention.

For example, a combination of a compound capable of generating an acid by photolysis with an acetal or an O, N-acetal compound (JP-A-48-89003), or a combination of an orthoester or amide acetal compound (JP-A-5-85300).
1-1120714), and a polymer having an acetal or ketal group in the main chain (JP-A-53-153).
No. 33429), a combination with an enol ether compound (JP-A-55-12995), and a combination with an N-acylimino carbon compound (JP-A-55-126236).
No.), a combination with a polymer having an orthoester group in the main chain (JP-A-56-17345), and a combination with a silyl ester compound (JP-A-60-10247).
And combination with silyl ether compound
0-37549, JP-A-60-12146) and the like.

The above compounds or combination systems may be used alone or in combination of two or more.

The water-insoluble and alkaline aqueous solution-soluble polymer compound mainly used in the layer (B) or (C) in the present invention can be a layer having a composition satisfying the relationship with the layer (A). There is no particular limitation as long as it is a layer, and in the case of the layer (B), the composition is more easily dissolved in the alkaline aqueous solution than the layer (A) depending on the alkali-soluble novolac resin used in the layer (A). In the case of (C), it is preferable to select from acrylic or urethane polymer compounds so that the composition is less likely to be dissolved in the alkaline aqueous solution than the layer (A).

The acrylic polymer compound is preferably a copolymer having a structural unit derived from at least one of the following monomers (1) to (4).

(1) Acrylamides, methacrylamides, acrylates and methacrylates having aromatic hydroxyl groups and hydroxystyrenes such as N- (4-hydroxyphenyl) acrylamide or N- (4-hydroxy). Phenyl) methacrylamide, o-, m-, p-hydroxyphenyl acrylate or methacrylate, o-, m-, p-hydroxystyrene and the like.

(2) Unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic anhydride and itaconic acid.

(3) A low molecular weight compound having at least one sulfonamide group having at least one hydrogen atom bonded to a nitrogen atom and one polymerizable unsaturated bond in one molecule, preferably an acryloyl group and allyl. Group or vinyloxy group, and a low-molecular compound having a substituted or mono-substituted aminosulfonyl group or substituted sulfonylimino group,
For example, compounds represented by the following formulas (I) to (V).

[0032]

Embedded image

The formula, X ^1, X ² are each -O- or -NR ⁷ - represents a. R ¹ and R ⁴ each represent a hydrogen atom or —CH ₃ . R ² , R ⁵ , R ⁹ , R ¹² , R ¹⁶
Each has 1 to 1 carbon atoms which may have a substituent.
2 represents an alkylene group, a cycloalkylene group, an arylene group or an aralkylene group. R ³ , R ⁷ and R ¹³ represent a hydrogen atom, an optionally substituted alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, an aryl group or an aralkyl group. R ⁶ and R ¹⁷ represent an optionally substituted alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, an aryl group or an aralkyl group. R ⁸ ,
R ¹⁰ and R ¹⁴ are each a hydrogen atom, a halogen atom or-
Represents CH ₃ . R ¹¹ and R ¹⁵ each represent a single bond or an optionally substituted alkylene group having 1 to 12 carbon atoms, a cycloalkylene group, an arylene group or an aralkylene group. Y ¹ and Y ² are each a single bond or -C.
Represents O-.

Specific examples include m-aminosulfonylphenyl methacrylate, N- (p-aminosulfonylphenyl) methacrylamide, N- (p-aminosulfonylphenyl) acrylamide and the like.

(4) A low molecular weight compound having one or more unsaturated bonds capable of polymerizing with an active imino group represented by the following formula (VI) in one molecule, for example, N- (p-toluenesulfonyl) methacrylimide. , N- (p-toluenesulfonyl) acrylimide and the like.

[0036]

Embedded image

The monomers corresponding to the above (1) to (4) may be used alone or in combination of two or more, but further polymerizable monomers other than the above (1) to (4). It is preferably a copolymer in combination with In this case, it is preferable that the structural unit derived from the monomers (1) to (4) is 10 mol% or more, preferably 20 mol% or more, more preferably 25 mol% or more. Such monomers used in combination with the above-mentioned monomers (1) to (4) are listed in, for example, the following (5) to (15).

(5) Acrylic acid esters and methacrylic acid esters having an aliphatic hydroxyl group, for example, 2
-Hydroxyethyl acrylate or 2-hydroxyethyl methacrylate.

(6) Methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate,
Benzyl acrylate, 2-chloroethyl acrylate,
(Substituted) alkyl acrylates such as glycidyl acrylate and N-dimethylaminoethyl acrylate.

(7) Methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate,
(Substituted) alkyl methacrylates such as amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, glycidyl methacrylate, and N-dimethylaminoethyl methacrylate.

(8) Acrylamide, methacrylamide, N-methylolacrylamide, N-ethylacrylamide, N-hexylmethacrylamide, N-cyclohexylacrylamide, N-hydroxyethylacrylamide, N-phenylacrylamide, N-nitrophenylacrylamide, N -Acrylamides such as ethyl-N-phenylacrylamide or methacrylic acid amides.

(9) Ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether,
Vinyl ethers such as octyl vinyl ether and phenyl vinyl ether.

(10) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate and vinyl benzoate.

(11) Styrene, α-methylstyrene,
Styrenes such as methylstyrene and chloromethylstyrene.

(12) Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone and phenyl vinyl ketone.

(13) Olefins such as ethylene, propylene, isobutylene, butadiene and isoprene.

(14) N-containing vinyl compounds such as N-vinylpyrrolidone, N-vinylcarbazole, 4-vinylpyridine, acrylonitrile and methacrylonitrile.

(15) Unsaturated imides such as maleimide, N-acryloylacrylamide, N-acetylmethacrylamide, N-propionylmethacrylamide and N- (p-chlorobenzoyl) methacrylamide.

Further, a monomer copolymerizable with these monomers may be copolymerized. These polymer compounds have a weight average molecular weight of 2000 or more and a number average molecular weight of 1
Those of 000 or more are preferably used. More preferably, the weight average molecular weight is 5,000 to 300,000, the number average molecular weight is 2,000 to 250,000, and the dispersity (weight average molecular weight / number average molecular weight) is 1.1 to 10. These polymer compounds may be used alone or in combination of two or more.

In the present invention, the urethane-based polymer compound as the polymer compound which is mainly used in the layer (B) or (C) and is insoluble in water and soluble in alkaline aqueous solution is insoluble in water and soluble in alkaline aqueous solution. There are no particular restrictions,
The layer (B) and the layer (C) may be appropriately selected and used depending on the type. Such urethane polymer compounds are disclosed in, for example, JP-A-63-124047 and JP-A-63-287946.
And the polymer compounds described in JP-A-2-866 and JP-A-2-156241.
These polymer compounds may be used alone or in combination of two or more.

In the present invention, the above acrylic polymer compound and urethane polymer compound may be used in combination as the main components of the layer (B) or (C).

On the other hand, in the present invention, the main components of the layer (A) are the alkali-soluble novolac resin and the photosensitive compound acting as a positive type, but the content of the alkali-soluble novolac resin in the layer (A) is the layer ( It is preferably from 30 to 90% by weight, more preferably from 40 to 85% by weight, of the total composition of A), and the content of the photosensitive compound acting as a positive type is from 10 to 70% by weight of the total composition of the layer (A). Wt%, even 1
It is preferably 5 to 60% by weight. In this case, the layer (A) may contain a water-insoluble and alkaline aqueous solution-soluble polymer compound which is the main component of the layer (B) or (C). At that time, the polymer compound insoluble in water and soluble in the alkaline aqueous solution was added to the alkali-soluble novolac resin in an amount of 4
It is preferably 0% by weight or less.

The main component of the layer (B) or (C) is a water-insoluble and alkaline aqueous solution-soluble, preferably acrylic or urethane polymer compound, but the layer (B) or (C) is a layer ( A small amount of alkali-soluble novolak resin, which is the main component of A), may be contained. At that time, the alkali-soluble novolac resin is preferably 50% by weight or less with respect to the polymer compound insoluble in water and soluble in the alkaline aqueous solution. Further, the layer (A) is added to the layer (B) or (C).
It may contain a photosensitive compound acting as a positive type, which is the main component of At that time, the content of the photosensitive compound acting as a positive type is 0 in the whole composition in the layer (B) or (C).
˜50 wt%, preferably 0-40 wt%.

In the present invention, when a photosensitive layer is provided as a combination of the layer (A) and the layer (B), a photosensitive solution for coating and a composition of the layer (B) are selected according to the composition of the layer (A). The layer can be formed by coating and drying the layer (B) on the support, and then further coating and drying the layer (A) according to the order of lamination, using the respective photosensitive liquids for coating. On the other hand, when the combination of the layer (A) and the layer (C) is used, a photosensitive solution for coating according to the composition of the layer (A) and a photosensitive solution for coating according to the composition of the layer (C) are used. Each of them can be used by applying and drying the layer (A) on the support and then applying and drying the layer (C) according to the order of lamination.

When the photosensitive layer is separately coated into two layers (A) and (B) or layers (A) and (C), both are generally mixed and do not clearly form two layers. Mixing of components at the contact interface between the two layers as described above or in the vicinity thereof is allowed, and the following method can be considered in order to clearly separate each layer into a coating film. Specifically, i) a method of utilizing the difference in solvent solubility between an alkali-soluble novolak resin and a polymer compound insoluble in water and soluble in an alkaline aqueous solution, and ii) drying the solvent extremely quickly after applying the second layer There is a method.

These will be described in more detail below, but the method of coating in two layers is not limited to this.

The method of utilizing the difference in solvent solubility between the alkali-soluble novolac resin and the polymer compound insoluble in water and soluble in an alkaline aqueous solution in i) is as follows: first, when the second layer is formed by coating later. A solvent system in which the main component of the first layer to be applied and coated on is insoluble is used. As a result, even if two-layer coating is performed, each layer can be clearly separated to form a coating film. More specifically, when the layer (B) is formed as the first layer and the layer (A) is formed as the second layer on the support, the second layer is selected from the coating solvents described below. A solvent that dissolves the alkali-soluble novolac resin as the main component of the layer (A) and a photosensitive compound that acts as a positive type, such as methyl ethyl ketone or 1-methoxy-2-propano-
Layer, etc., which is insoluble in this solvent (first)
A polymer compound insoluble in water and soluble in an alkaline aqueous solution may be selected to form a coating layer. First, a solvent system that dissolves the above polymer compound for layer (B) is used to form layer (B). Is applied and dried to form a first layer, and then, as a second layer, a layer (A) mainly composed of an alkali-soluble novolac resin and a positive-working photosensitive compound is added to methyl ethyl ketone or 1-methoxy-2-propano- By using a solvent that does not dissolve the polymer compound for the layer (B), such as a resin, it is possible to form a double layer. The same applies when the layer (A) is provided as the first layer and the layer (C) is provided as the second layer.

On the other hand, the method of drying the solvent extremely quickly after applying the second layer of ii) is to blow high pressure air from a slit nozzle installed at a right angle to the running direction of the web or to heat steam or the like. This can be achieved by applying heat energy as conduction heat from the lower surface of the web from a roll (heating roll) that is internally supplied with the medium, or by combining them.

In the method of ii), the first layer [layer (B) or layer (A)] is applied and dried to form a layer, and then the second layer [layer (A) or layer (C)] is formed. FIG. 1 shows an example of the configuration of an apparatus for carrying out continuous coating and drying, which is used for this. FIG.
In the apparatus of (1), for example, a roughened aluminum web is used as a support, and a second layer is applied to a first-layer coating product in which the first layer is applied in advance on the support. .

The apparatus shown in FIG. 1 includes a coating head 2 for coating the first layer coating material 1 with the second layer photosensitive liquid, and a first drying zone 3 for drying with hot air and high speed air for high speed drying. And a second drying zone 4 for drying with hot air. In the first drying zone 3, an air supply port 5 for sending hot air and a high pressure air generator 9 for performing high speed drying, a heat exchanger 10, a pressure gauge 11, a high pressure air blowing nozzle 12 and air volume control dampers 18, 19 are provided. And an exhaust port 6 for discharging hot air out of the system. Second drying zone 4
An air supply port 7 for sending hot air and an exhaust port 8 for discharging hot air to the outside of the system are installed in the. Further, guide rolls 13 to 17 for conveying the aluminum web 1 are installed at appropriate positions of this apparatus.

In such an apparatus, the coating solution 1 for the first layer, which continuously runs at 5 to 150 m / min, is coated with the photosensitive solution for the second layer at a rate of 5 to 40 ml / m ² by the coating head 2, and thereafter Guided to the first drying zone 3, hot air having a normal temperature of 50 to 150 ° C. is sent out from the air supply port 5, and the first layer coating material 1 is dried. The evaporated solvent gas is entrained in the hot air and discharged from the exhaust port 6 to the outside of the system. At the stage of being dried by hot air in the vicinity of the inlet inside the first drying zone 3, the second layer coating film is usually in an undried state.

This undried second-layer coating film is dried extremely rapidly by the high-speed air blown from the high-speed blow-out nozzle 12 installed at the conveying position at a right angle to the traveling direction of the first-layer coating material 1. To be done.

To the high-speed air blowing nozzle 12, high-pressure air generated by a high-pressure air generator 9 composed of a compressor or a high-pressure blower is heated by a heat exchanger 10 at 50 ° C.
The mixture is heated to 200 ° C., adjusted to a desired air volume by air volume adjustment dampers 18 and 19, and then supplied. This makes it possible to rapidly evaporate the solvent in a very short time to form the second layer by violently colliding the slit-shaped high-pressure air having a desired temperature and wind velocity with the undried second-layer coating film. Normally, the pressure in the nozzle 12 of high pressure air is 300 mmAq (H ₂
O) to 3 kg / cm ² , preferably 1000 mmAq to 1 kg
/ cm ² . The speed of the high-pressure air blowing nozzle 12 is about 20 m / s to 300 m / s. The slit interval of the high-speed air blowing nozzle 12 is about 0.1 mm to 5 mm, but a range of 0.3 mm to 1 mm is preferable. Furthermore, the high-pressure air is blown onto the first layer coating material 1 at an angle of 0 ° to 90 °.
However, 10 ° to 60 ° is preferable. Although the number of nozzles is two in the illustrated example, it may be about 1 to 8 depending on the drying load.

In this way, high speed drying is performed in the first drying zone 3 to form a coating film for the second layer. After that, the first layer coating material 1 on which the second layer is formed is guided to the second drying zone 4 and heated by hot air of 100 ° C. to 150 ° C. from the air supply port 7. As a result, the amount of residual solvent remaining in the film in a trace amount is controlled within the range of 30 to 200 mg / m ² . Also,
The solvent gas is discharged out of the system through the exhaust port 8.

The desired two-layer coating can be achieved by these drying operations.

Further, in the present invention, as a method for carrying out the above method ii), drying by a heating roll may be performed instead of drying by the high speed air as described above. In FIG. 1, a high-pressure air generator 9, a heat exchanger 10, a pressure gauge 11, a high-pressure air blowing nozzle 1
2 and the air volume adjusting dampers 18 and 19 may be omitted, and the guide roll 14 may be a heating roll. In such a case, the surface temperature of the roll can be heated to 80 to 200 ° C. by supplying a heating medium such as steam to the inside of the roll. By contacting the surface of the heating roll with the aluminum web of the first layer coating material 1, heat energy can be applied by conduction heat from the lower surface of the first layer coating material 1 on the aluminum web side, and drying can be performed.

Further, the method of ii) can be carried out by combining the drying with the high speed air and the drying with the heating roll. As the apparatus in this case, for example, the one in which the guide roll 14 in FIG. 1 is the same heating roll as described above may be used, and the solvent can be evaporated more rapidly.

In the above example shown in FIG. 1 etc., the first
Although hot air drying is performed in the drying zone 3 and then hot air drying and high pressure air drying or heating roll drying are performed together, the first hot air drying is omitted, and high pressure air drying is performed immediately after coating. It doesn't matter.

In the present invention, it is efficient and preferable to continuously apply and dry the coating and drying apparatus as shown in FIG. Further, the coating / drying of the first layer is performed by installing the same device as that for the second layer upstream of the device for coating / drying the second layer, and further roughening the support to coat / dry the first layer. In order to improve the productivity, it is preferable to carry out the treatment by providing a roughening means upstream of the coating head of the drying device and continuously moving the support continuously.

In the present invention, the layer (A), the layer (B) and the layer (C) are, as described above, depending on the layer structure of the photosensitive layer, the photosensitive solution for coating the layer (A) and the coating solution for the layer (B), respectively. It is formed using the photosensitive solution for coating and the photosensitive solution for coating the layer (C). The photosensitive compositions of the layer (A), the layer (B) and the layer (C) thus formed include Further, various additives can be added if necessary.

For example, cyclic acid anhydrides, phenols, and organic acids may be used in combination for the purpose of improving sensitivity. As the cyclic acid anhydride, there is US Pat. No. 4,115,128.
, Phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 3,6-endooxy-Δ ⁴ -tetrahydrophthalic anhydride, tetrachlorophthalic anhydride, maleic anhydride, chloromaleic anhydride , Α-phenyl maleic anhydride, succinic anhydride,
Pyromellitic anhydride and the like can be used. As phenols, bisphenol A, p-nitrophenol, p
-Ethoxyphenol, 2,4,4'-trihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 4-hydroxybenzophenone, 4,4 ',
4 "-trihydroxytriphenylmethane, 4,4 ',
3 ", 4" -tetrahydroxy-3,5,3 ', 5'-
Examples thereof include tetramethyltriphenylmethane. Further, as organic acids, JP-A-60-88942,
Sulfonic acids, sulfinic acids, alkyl sulfurs, which are described in JP-A-2-96755 and the like.
Examples include phosphonic acids, phosphoric esters and carboxylic acids, and specifically, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, p-toluenesulfinic acid,
Ethyl sulfate, phenylphosphonic acid, phenylphosphinic acid, phenyl phosphate, diphenyl phosphate, benzoic acid, isophthalic acid, adipic acid, p-toluic acid, 3,4-dimethoxybenzoic acid, phthalic acid, terephthalic acid, 1,4 −
Cyclohexene-2,2-dicarboxylic acid, erucic acid, lauric acid, n-undecanoic acid, ascorbic acid and the like. The ratio of the above cyclic acid anhydride, phenols and organic acids in the photosensitive composition is 0.05 to 1
5% by weight is preferred, more preferably 0.1-5% by weight
It is.

Further, in the photosensitive composition of the present invention, in order to extend the stability of the processing under the developing conditions, JP-A-62-251740 and JP-A-3-208514 are used.
Non-ionic surfactants described in JP-A-59-121044, JP-A-4-13149.
An amphoteric surfactant such as that described in JP-A No. 2-211 can be added. Specific examples of the nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan triolate, monoglyceride stearic acid, and polyoxyethylene nonyl phenyl ether. Specific examples of the double-sided activator include alkyldi (aminoethyl) glycine, alkylpolyaminoethylglycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine and N-tetradecyl-N, N-. Betaine type (for example,
(Trade name: Amogen K, manufactured by Dai-ichi Kogyo Co., Ltd.). The proportion of the nonionic surfactant and the amphoteric surfactant in the photosensitive composition is preferably 0.05 to 15% by weight, more preferably 0.1 to 5% by weight.

In the photosensitive composition of the present invention, a printing-out agent for obtaining a visible image immediately after exposure and a dye or pigment as an image colorant can be added. Representative examples of the printing-out agent include a combination of a compound that releases an acid upon exposure (photoacid releasing agent) and an organic dye that can form a salt. Specifically, JP-A-50-3620
No. 9 and No. 53-8218 described in o
A combination of a naphthoquinonediazide-4-sulfonic acid halogenide and a salt-forming organic dye;
No. 54, No. 54-74728, No. 60-3626, No. 6
Combinations of trihalomethyl compounds and salt-forming organic dyes described in JP-A Nos. 1-143748, 61-151644 and 63-58440 can be exemplified. Examples of such trihalomethyl compounds include:
There are oxazole compounds and triazine compounds,
Both have excellent stability over time and give clear printed images.

As the image colorant, other dyes can be used in addition to the above-mentioned salt-forming organic dyes. Suitable dyes include oil-soluble dyes and basic dyes, including salt-forming organic dyes. Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink #
312, oil green BG, oil blue BOS, oil blue # 603, oil black BY, oil black BS, oil black T-505 (all manufactured by Orient Chemical Industry Co., Ltd.), Victoria Pure Blue, crystal violet (CI42555), methyl Violet (CI42535), ethyl violet, rhodamine B (CI145170B), malachite green (CI42000), methylene blue (CI5201)
5) and the like. Further, Japanese Patent Application Laid-Open No.
The dyes described in Japanese Patent No. 93247 are particularly preferable. These dyes are based on the total solid content of the photosensitive composition,
It can be added to the photosensitive composition in an amount of 0.01 to 10% by weight, preferably 0.1 to 3% by weight.

If necessary, a plasticizer is added to the photosensitive composition of the present invention in order to impart flexibility to the coating film. For example, butylphthalyl, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate,
Tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, oligomers and polymers of acrylic acid or methacrylic acid, and the like are used.

In the present invention, the layer (A), the layer (B) and the layer (C) dissolve the solvent of the component of the layer (A) and the component of the layer (B) depending on the layer constitution of the photosensitive layer. And a solvent for dissolving the components of the layer (C) are used, and a photosensitive solution in which each component corresponding to each layer composition is dissolved is used for coating. When two layers are formed by utilizing the difference in the solubility of the solvent, the solvent type may be selected as described above.

The coating solvent used in the present invention includes a ketone system such as cyclohexanone and methyl ethyl ketone, methanol, ethanol, propanol and 1-methoxy-2.
-Alcohol such as propanol, cellosolve such as ethylene glycol monomethyl ether, lactone such as γ-butyrolactone, sulfoxide such as dimethyl sulfoxide and sulfolane, halogen such as ethylene dichloride, 2-methoxyethyl acetate, 1-methoxy- Acetate such as 2-propylacetate, ether such as dimethoxyethane, ester such as methyl lactate and ethyl lactate, N, N-dimethoxyacetamide, N, N
Examples include amide-based compounds such as dimethylformamide, pyrrolidone-based compounds such as N-methylpyrrolidone, urea-based compounds such as tetramethylurea, and aromatic-based compounds such as toluene.

Of these, methyl ethyl ketone, 1-methoxy-2-propanol, ethylene glycol monomethyl ether, γ-butyrolactone, dimethyl sulfoxide and the like are preferable.

These solvents may be used alone or as a mixture.

The concentration of the above components (total solid content including additives) in the solvent in the photosensitive solution is preferably 1 to 50% by weight.
It is. Particularly in the case of the method ii), the concentration of the photosensitive solution for coating the second layer is preferably as high as possible in order to dry more rapidly, and is preferably 10 to 50% by weight. The coating amount (solid content) on the support obtained after coating and drying varies depending on the use, but as described above, in the case of a photosensitive printing plate, it is generally 0.5 to 5.0 g / m ² is preferred.

Various methods can be used for coating, and examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating. You can As the coating amount decreases, the apparent sensitivity increases, but the film characteristics of the photosensitive film deteriorate.

In the photosensitive layer according to the present invention, a surfactant for improving the coating property, such as JP-A-62-1709.
Fluorine-based surfactants such as those described in Japanese Patent Publication No. 50 can be added. The preferable addition amount is 0.01 to 1% by weight of the total photosensitive composition, more preferably 0.0.
5 to 0.5% by weight.

The support used in the present invention is a dimensionally stable plate-like material such as paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate ( For example, aluminum, zinc, copper, etc., plastic film (eg, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate,
Cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), paper laminated with the above-mentioned metals, or vapor-deposited, or a plastic film. Among them, an aluminum plate, which has good dimensional stability and is relatively inexpensive, is particularly preferable.
The preferred aluminum plate is a pure aluminum plate or an alloy plate containing aluminum as a main component and a slight amount of a foreign element, and may be an aluminum laminated or vapor-deposited plastic film. The foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel and titanium. The content of the foreign element in the alloy is at most 10% by weight or less. Particularly preferred aluminum in the present invention is
Although it is pure aluminum, completely pure aluminum is difficult to produce due to refining technology, and therefore may contain a slightly different element. As described above, the aluminum plate applied to the present invention is not specified in its composition, and an aluminum plate which is a conventionally known and publicly known material can be appropriately used. The thickness of the aluminum plate used in the present invention is about 0.1 mm to 0.6 mm.

Prior to the roughening of the aluminum plate, if desired, a degreasing treatment for removing rolling oil on the surface is carried out, for example, with a surfactant, an organic solvent or an alkaline aqueous solution. The surface roughening treatment of the surface of the aluminum plate is performed by various methods, for example, a method of mechanically roughening the surface, a method of electrochemically dissolving the surface, and a method of selectively dissolving the surface chemically. It is performed by the method of causing. As a mechanical method, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, and a buff polishing method can be used. As an electrochemical graining method, there is a method of performing alternating current or direct current in a hydrochloric acid or nitric acid electrolytic solution. Further, as disclosed in JP-A-54-63902, a method of combining the two can also be used. The thus roughened aluminum plate is subjected to alkali etching treatment and neutralization treatment, if necessary, and then subjected to anodization treatment if desired in order to enhance water retention and abrasion resistance of the surface. As the electrolyte used for the anodizing treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used, and sulfuric acid, phosphoric acid, oxalic acid, chromic acid or a mixed acid thereof is generally used. The concentration of these electrolytes is appropriately determined depending on the type of the electrolyte.

The treatment conditions for anodic oxidation cannot be unconditionally specified because they vary depending on the electrolyte used, but generally the concentration of the electrolyte is 1 to 80% by weight solution, the liquid temperature is 5 to 70 ° C., and the current density is 5 to 5. 60A / dm ² , voltage 1-100V, electrolysis time 1
A range of 0 seconds to 5 minutes is appropriate. If the amount of anodized film is less than 1.0 g / m ² , printing durability is insufficient, or the non-image area of the lithographic printing plate is easily scratched, and ink adheres to the scratched area during printing. So-called "scratch stains" tend to occur. After the anodizing treatment, the aluminum surface is subjected to a hydrophilic treatment as necessary. Examples of the hydrophilic treatment used in the present invention include US Pat. No. 271406.
No. 6, No. 3,181,461, No. 3,280,734 and No. 3,902,734, there are alkali metal silicate (for example, sodium silicate aqueous solution) methods. In this method, the support is immersed in an aqueous solution of sodium silicate or electrolytically treated. Besides, potassium fluorozirconate disclosed in JP-B-36-22063 and US Pat. No. 3,276,868.
No. 4,153,461 and No. 4,689,272, the method of treating with polyvinyl phorphonic acid is used.

The positive-working photosensitive lithographic printing plate of the present invention comprises a support having thereon a photosensitive layer formed of a positive-working photosensitive composition. If necessary, an undercoat layer may be provided between them. A mat layer can be provided on the photosensitive composition layer. Various organic compounds are used as the undercoat layer component, and examples thereof include phosphonic acids having an amino group such as carboxymethyl cellulose, dextrin, gum arabic, and 2-aminoethylphosphonic acid, and phenylphosphonic acid which may have a substituent. , Naphthylphosphonic acid, alkylphosphonic acid, glycerophosphonic acid, organic phosphonic acids such as methylenediphosphonic acid and ethylenediphosphonic acid, optionally substituted phenylphosphoric acid, naphthylphosphoric acid, alkylphosphoric acid and glycerophosphoric acid, etc. Organic phosphoric acid, phenylphosphinic acid which may have a substituent, naphthylphosphinic acid, organic phosphinic acid such as alkylphosphinic acid and glycerophosphinic acid, amino acids such as glycine and β-alanine, and hydrochloric acid of triethanolamine Hydroxy such as salt Although selected from such as hydrochloric acid salt of an amine with, it may be used by mixing two or more.

This organic undercoat layer can be provided by the following method. That is, water or a solvent in which the above organic compound is dissolved in an organic solvent such as methanol, ethanol, or methyl ethyl ketone or a mixed solvent thereof is applied onto an aluminum plate and dried, and a method of providing water or methanol, ethanol, methyl ethyl ketone, or the like. Is a method in which an aluminum plate is immersed in a solution prepared by dissolving the above organic compound in an organic solvent or a mixed solvent thereof to adsorb the above compound, followed by washing with water or the like and drying to form an organic undercoat layer. . In the former method, a solution of the above organic compound having a concentration of 0.005 to 10% by weight can be applied by various methods. In the latter method, the concentration of the solution is 0.01 to 20% by weight, preferably 0.05 to 5%.
% By weight, the immersion concentration is 20 to 90 ° C., preferably 2
It is 5 to 50 ° C., and the immersion time is 0.1 second to 20 minutes, preferably 2 seconds to 1 minute. The solution used for this has a pH of 1 to 12 with basic substances such as ammonia, triethylamine and potassium hydroxide, and acidic substances such as hydrochloric acid and phosphoric acid.
It can also be modified within the range. Further, a yellow dye can be added for improving the tone reproducibility of the photosensitive lithographic printing plate. The coating amount of the organic undercoat layer is appropriately ² to 200 mg / m ² , and preferably 5 to 100 mg / m ² . If the coating amount is less than 2 mg / m ² , sufficient printing durability cannot be obtained. The same applies when the amount is larger than 200 mg / m ² .

Further, on the surface of the photosensitive layer formed of the positive photosensitive composition of the present invention, in order to shorten the vacuuming time at the time of contact exposure using a vacuum baking frame, and to prevent baking blur. , A mat layer is provided. Specifically, JP-A-50-1
No. 25805, Japanese Patent Publication No. 57-6582, 61-28
No. 986, a method of providing a matte layer, a method of heat-bonding a solid powder as described in JP-B-62-62337 and the like can be mentioned. The average diameter of the mat layer used in the present invention is 100 μm.
The following is preferable, and a more preferable range is 2 to 8 μm.
It is. When the average diameter is large, it is difficult to form a thin line and the number of highlight dots is reduced, which is not preferable in tone reproduction. When the average diameter is 2 μm or less, vacuum adhesion is insufficient and baking blur occurs. The coating amount of the matte layer is preferably 5 to 200 mg / m ² , and more preferably 20 to 150 mg / m ² . If the coating amount is larger than this range, it causes friction, and if it is smaller than this range, the vacuum adhesion is insufficient.

The positive type photosensitive lithographic printing plate produced as described above is usually subjected to image exposure and development processing. Examples of the light source of actinic rays used for image exposure include a mercury lamp, a metal halide lamp, a xenon lamp, a chemical lamp, and a carbon arc lamp. Examples of the radiation include an electron beam, an X-ray, an ion beam, and a far-infrared ray. Further, g-line, i-line, Deep-UV light, and high-density energy beam (laser beam) are also used. Examples of the laser beam include a helium / neon laser, an argon laser, a krypton laser, a helium / cadmium laser, a KrF excimer laser, and the like.

As the developer and replenisher for the positive-working photosensitive lithographic printing plate of the present invention, conventionally known alkaline aqueous solutions can be used. For example, sodium silicate, potassium silicate, sodium phosphate tribasic, potassium phosphate tribasic, ammonium phosphate tribasic, sodium phosphate dibasic,
Dibasic potassium phosphate, dibasic ammonium phosphate, sodium carbonate, potassium carbonate, ammonium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, ammonium hydrogen carbonate, sodium borate, potassium borate, ammonium borate, sodium hydroxide, ammonium hydroxide, Inorganic alkali salts such as potassium hydroxide and lithium hydroxide are mentioned. Further, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, Organic alkaline agents such as ethylenediamine, ethyleneimine and pyridine are also used. These alkali agents are used alone or in combination of two or more. Among these alkali agents, particularly preferred developers are aqueous silicate solutions such as sodium silicate and potassium silicate. The reason is that silicon oxide SiO2, which is a component of silicate, and alkali metal oxide M2 O.
This is because the developability can be controlled by the ratio and concentration of the alkali metal silicates. For example, alkali metal silicates described in JP-A-54-62004 and JP-B-57-7427 are effective. Used.

Furthermore, in the case of developing using an automatic processor, an aqueous solution (replenisher) having a higher alkaline strength than the developing solution is used.
It is known that a large amount of PS plate can be processed by replacing the developer in the developing tank for a long time without adding the developer to the developer. Also in the present invention, this replenishment system is preferably applied. In the developer and replenisher used in the present invention, various surfactants and organic solvents may be added as necessary for the purpose of promoting or suppressing developability, dispersing development residue and enhancing the ink affinity of the printing plate image area. Can be added. Preferred surfactants include anionic, cationic, nonionic and amphoteric surfactants. Further, in the developer and replenisher used in the present invention, hydroquinone, resorcin, sulfurous acid, a reducing agent such as a sodium salt of an inorganic acid such as bisulfite, a potassium salt, an organic carboxylic acid, an antifoaming agent. Agents and water softeners can be added. The printing plate developed using the above developer and replenisher is post-treated with washing water, a rinsing solution containing a surfactant and the like, and a desensitizing solution containing gum arabic and a starch derivative. Various combinations of these treatments can be used for the post-treatment of the printing plate of the present invention.

In recent years, automatic developing machines for printing plates have been widely used in the plate making / printing industry in order to rationalize and standardize the plate making work. This automatic developing machine generally comprises a developing section and a post-processing section, and comprises a device for transporting a printing plate, each processing solution tank and a spray device, and while pumping the exposed printing plate horizontally, each pumped by a pump. The developing process is performed by spraying a processing liquid from a spray nozzle. Further, recently, a method has also been known in which a printing plate is dipped and conveyed by a submerged guide roll or the like in a processing liquid tank filled with the processing liquid for processing. In such an automatic processing, the processing can be performed while replenishing each processing liquid with a replenisher according to the processing amount, the operating time, and the like. Further, a so-called disposable processing method in which processing is performed with a substantially unused processing liquid can also be applied. The photosensitive lithographic printing plate of the present invention is imagewise exposed, developed, washed and / or rinsed and / or gummed to obtain an unnecessary image portion (for example, a film edge trace of an original film). In some cases, the unnecessary image portion is erased. Such erasing is preferably performed, for example, by applying an erasing liquid as described in Japanese Patent Publication No. 2-13293 to the unnecessary image portion, leaving it for a predetermined time as it is, and then rinsing with water. A method described in JP-A-59-174842, in which an active ray guided by an optical fiber is applied to an unnecessary image portion and then developed, can also be used.

The lithographic printing plate obtained as described above can be subjected to a printing step after applying a desensitizing gum if desired, but when a lithographic printing plate having higher printing durability is desired, Is subjected to a burning process. When burning a lithographic printing plate, before printing
No. 2518, No. 55-28062, JP-A-62-3
It is preferable to treat with a surface-regulating liquid as described in JP-A Nos. 1859 and 61-159655. As a method, a sponge or absorbent cotton soaked with a surface-adjusting solution is applied on the planographic printing plate, or a printing plate is immersed in a vat filled with the surface-adjusting solution, or an automatic coater. And the like are applied. Further, making the coating amount uniform with a squeegee or a squeegee roller after coating gives more preferable results. In general, a suitable amount of the surface-adjusting solution is 0.03 to 0.8 g / m2 (dry weight). The planographic printing plate coated with the surface-adjusting solution is dried, if necessary, and then heated to a high temperature with a burning processor (for example, burning processor: BP-1300 sold by Fuji Photo Film Co., Ltd.). The heating temperature and time in this case depend on the type of the component forming the image, but are preferably in the range of 180 to 300 ° C. and 1 to 20 minutes. The lithographic printing plate subjected to the burning treatment can be subjected to conventional treatments such as washing with water and gumming, if necessary, but a surface-adjusting solution containing a water-soluble polymer compound or the like was used. In some cases, so-called desensitizing treatment such as gumming can be omitted. The planographic printing plate obtained by such treatment is applied to an offset printing machine or the like and used for printing a large number of sheets.

[0094]

EXAMPLES The present invention will be specifically described below with reference to Examples showing Comparative Examples. Example 1 A 0.3 mm-thick aluminum plate (material 1050) was washed with trichlorethylene to degrease it, and then its surface was grained using a nylon brush and a 400 mesh pumice-water suspension, and washed well with water. 25% of this plate at 45 ℃
It was immersed in a sodium hydroxide aqueous solution for 9 seconds for etching, washed with water, and further immersed in 20% nitric acid for 20 seconds and washed with water. At this time, the etching amount of the grained surface is about 3 g / m ²
Met. Next, this plate was used as a 7% sulfuric acid electrolytic solution to form a direct current anodic oxide coating of 3 g / m ² at a current density of 15 A / dm ² , and then washed with water and dried. Next, the following undercoat liquid was applied to this aluminum plate and dried at 80 ° C. for 30 seconds. The coating amount after drying was 10 mg / m ² .

(Undercoating liquid) β-alanine 0.1 g Phenylphosphonic acid 0.05 g Methanol 40 g Pure water 60 g

Further, on the aluminum plate, the following photosensitive solution B was added.
1 was applied and dried at 100 ° C. for 2 minutes. The coating amount after drying was 1.3 g / m ² .

(Photosensitive solution B1) N- (p-aminosulfonylphenyl) methacrylamide / acrylonitrile / methyl methacrylate copolymer (molar ratio 45/30/25, weight average molecular weight 75000) 1.6 g naphthoquinone-1,2 -Esterification product of diazide-5-sulfonic acid chloride and 2,3,4-trihydroxybenzophenone (esterification rate 90%) 0.25 g Naphthoquinone-1,2-diazide-4-sulfonic acid chloride 0.005 g Tetrahydro Phthalic anhydride 0.03 g 4- (p-N, N-diethoxycarbonylaminophenyl) -2,6-bis (trichloromethyl) -s-triazine 0.01 g 4- (p-hydroxybenzoylaminophenyl) -2 , 6-bis (trichloromethyl) -s-triazine 0.01 g Victoria Pure Blue BOH Dye whose counter ion is 1-naphthalenesulfonic acid anion 0.015 g γ-butyl lactone 8 g Methyl ethyl ketone 10 g 1-methoxy-2-propanol 7 g

Further, the following photosensitive solution A1 was applied to an aluminum plate coated with the photosensitive solution B1 and dried at 100 ° C. for 2 minutes to obtain a positive photosensitive lithographic printing plate 1. The total coating amount after drying was 2.0 g / m ² .

(Photosensitive solution A1) m, p-cresol novolak (m, p ratio = 6/4, weight average molecular weight 3500, containing 0.5% by weight of unreacted cresol) 0.7 g naphthoquinone-1,2-diazide- Esterification product of 5-sulfonic acid chloride and 2,3,4-trihydroxybenzophenone (esterification rate 90%) 0.6 g Naphtoquinone-1,2-diazide-4-sulfonic acid chloride 0.005 g The following formula (VII 0.05 g of tetrahydrophthalic anhydride 0.02 g 4- (p-N, N-diethoxycarbonylaminophenyl) -2,6-bis (trichloromethyl) -s-triazine 0.01 g 4- (p- Hydroxybenzoylaminophenyl) -2,6-bis (trichloromethyl) -s-triazine 0.01 g Victoria Pure Blue BOH pair Dyes whose ions are 1-naphthalene sulfonic acid anion 0.015g Megafac F-177 (Dainippon Ink and Chemicals, Inc., fluorine-based surfactant) 0.05g Methyl ethyl ketone 30g

Example 2 In the photosensitive solution A1 of Example 1, naphthoquinone-1,2 was used.
-The esterification product of diazide-5-sulfonic acid chloride and 2,3,4-trihydroxybenzophenone was converted to naphthoquinone-1,2-diazide-5-sulfonic acid chloride and pyrogallol-acetone resin (weight average molecular weight 350
0) The positive photosensitive lithographic printing plate 2 was obtained in exactly the same manner as in Example 1 except that the esterification product (esterification rate was 50%) was used.

Example 3 In the photosensitive solution B1 of Example 1, the amount of N- (p-aminosulfonylphenyl) methacrylamide / acrylonitrile / methyl methacrylate copolymer added was 1.45 g, and m, p-cresol novolac was used. (M / p ratio = 6 /
4, weight average molecular weight 3500, unreacted cresol 0.5
0.1% by weight) was added to the photosensitive solution A1 to prepare an esterification product of naphthoquinone-1,2-diazide-5-sulfonic acid chloride and 2,3,4-trihydroxybenzophenone with naphthoquinone-1,2-. Diazide
A positive photosensitive lithographic printing plate 3 was obtained in exactly the same manner as in Example 1 except that the esterification product (esterification rate: 50%) of 5-sulfonic acid chloride and pyrogallol-acetone resin (weight average molecular weight: 3500) was used. It was

Example 4 In the photosensitive solution B1 of Example 1, N- (p-aminosulfonylphenyl) methacrylamide / acrylonitrile / methyl methacrylate copolymer was replaced with p- (1,1-dihydroxymethylethylcarbonylamino) benzene. A positive-working photosensitive lithographic printing plate 4 was obtained in exactly the same manner as in Example 1 except that the condensation polymer of sulfonamide / 4,4'-diphenylmethane diisocyanate (weight average molecular weight: 32000) was used.

Example 5 The following photosensitive solution A2 was applied to an aluminum plate which had been subjected to undercoating in the same manner as in Example 1 and dried at 100 ° C. for 2 minutes. The coating amount after drying was 1.3 g / m ² .

(Photosensitive Solution A2) m, p-cresol novolak (m, p ratio = 6/4, weight average molecular weight 3500, containing 0.5% by weight of unreacted cresol) 1.2 g naphthoquinone-1,2-diazide- Esterification product (esterification rate 50%) of 5-sulfonic acid chloride and pyrogallol-acetone resin (weight average molecular weight 3500) 0.40 g Naphthoquinone-1,2-diazide-4-sulfonic acid chloride 0.005 g The following formula (VII) 0.05 g of tetrahydrophthalic anhydride 0.02 g 4- (p-N, N-diethoxycarbonylaminophenyl) -2,6-bis (trichloromethyl) -s-triazine 0.01 g 4- (p- Hydroxybenzoylaminophenyl) -2,6-bis (trichloromethyl) -s-triazine 0.01 g Victoria Pure Counterions Lou BOH to 1-naphthalenesulfonic acid anion emission dye 0.015g methyl ethyl ketone 30g

Further, the following photosensitive solution C1 was applied to an aluminum plate coated with the photosensitive solution A2 and dried to obtain a positive photosensitive lithographic printing plate 5. At that time, the drying is performed in the drying zone shown in FIG.
Blowing high pressure air of 00mmAq and guide roll 14
Was changed to a heating roll and heating at 130 ° C. was also performed. The total coating amount after drying was 2.0 g / m ² .

(Photosensitive solution C1) N- (p-aminosulfonylphenyl) methacrylamide / acrylonitrile / methyl methacrylate copolymer (molar ratio 25/30/45, weight average molecular weight 75000) 0.8 g m, p-cresol Novolac (m, p ratio = 6/4, weight average molecular weight 3500, containing 0.5% by weight of unreacted cresol) 0.2 g naphthoquinone-1,2-diazide-5-sulfonic acid chloride and 2,3,4-tol Esterification product with rehydroxybenzophenone (esterification rate 90%) 0.2 g Naphthoquinone-1,2-diazide-4-sulfonic acid chloride 0.005 g Tetrahydrophthalic anhydride 0.03 g 4- (p-N, N-di) Ethoxycarbonylaminophenyl) -2,6-bis (trichloromethyl) -s-triazine 0.01 g 4- (p-hydroxyben) Ilaminophenyl) -2,6-bis (trichloromethyl) -s-triazine 0.01g Victoria Pure Blue BOH counter ion as 1-naphthalenesulfonic acid anion 0.015g Megafac F-177 Ink Chemical Industry Co., Ltd., fluorine-based surfactant) 0.05 g γ-butyl lactone 2 g Methyl ethyl ketone 20 g 1-methoxy-2-propanol 1 g

Example 6 In the photosensitive solution A2 of Example 5, the amount of m, p-cresol novolac added was 1.05 g, and a methacrylic acid / methyl methacrylate copolymer (molar ratio = 25/75, weight average molecular weight) was used. 65000) in an amount of 0.15 g, and in the photosensitive solution C1, N- (p-aminosulfonylphenyl) methacrylamide / acrylonitrile / methyl methacrylate copolymer was replaced with methacrylic acid / methyl methacrylate copolymer (molar ratio = 12/88, weight average molecular weight 650
00), an esterified product of naphthoquinone-1,2-diazide-5-sulfonic acid chloride and 2,3,4-trihydroxybenzophenone, naphthoquinone-1,2-diazide-5-sulfonic acid chloride and pyrogallol-acetone resin. A positive photosensitive lithographic printing plate 6 was obtained in exactly the same manner as in Example 1 except that the esterification product (esterification rate 50%) with (weight average molecular weight 3500) was used.

Example 7 The following photosensitive solution B2 was applied to an aluminum plate which had been subjected to undercoating in the same manner as in Example 1 and dried at 100 ° C. for 2 minutes. The coating amount after drying was 1.0 g / m ² .

(Photosensitive solution B2) N- (p-toluenesulfonyl) acrylimide / acrylonitrile / methyl acrylate / benzyl acrylate copolymer (molar ratio 35/30/25/10, weight average molecular weight 50,000) 1. 1 g Phenol novolak (weight average molecular weight 9500, containing 1.1% by weight of unreacted cresol) 0.20 g Naphthoquinone-1,2-diazide-5-sulfonic acid chloride ester with 2,3,4-trihydroxybenzophenone Compound (esterification rate 90%) 0.1 g Naphthoquinone-1,2-diazide-4-sulfonic acid chloride 0.005 g Tetrahydrophthalic anhydride 0.03 g 4- (p-N, N-diethoxycarbonylaminophenyl)- 2,6-bis (trichloromethyl) -s-triazine 0.01 g 4- (p-hydroxybenzoylamino) Phenyl) -2,6-bis (trichloromethyl) -s-triazine 0.01 g Victoria Pure Blue BOH counter ion as 1-naphthalenesulfonic acid anion dye 0.015 g Methyl ethyl ketone 15 g 1-methoxy-2-propano- 12g

Further, the following photosensitive solution A3 was applied to an aluminum plate coated with the photosensitive solution B2 and dried to obtain a positive photosensitive lithographic printing plate 7. Drying is performed in the drying zone shown in the figure, and 3000 mmAq from the slit nozzle 12 immediately after coating.
High-pressure air was blown, the guide roll 14 was changed to a heating roll, and heated at 120 ° C. to dry. The total coating amount after drying was 2.0 g / m ² .

(Photosensitive solution A3) Phenol novolac (weight average molecular weight 9500, containing 1.1% by weight of unreacted cresol) 0.80 g naphthoquinone-1,2-diazide-5-sulfonic acid chloride and pyrogallol-acetone resin (weight Esterification product with an average molecular weight of 3500 (esterification rate: 50%) 0.6 g Naphthoquinone-1,2-diazide-4-sulfonic acid chloride 0.005 g Compound of the following formula (VII) 0.05 g Tetrahydrophthalic anhydride 0. 02 g 4- (p-N, N-diethoxycarbonylaminophenyl) -2,6-bis (trichloromethyl) -s-triazine 0.01 g 4- (p-hydroxybenzoylaminophenyl) -2,6-bis ( Trichloromethyl) -s-triazine 0.01 g Victoria Pure Blue BOH counter ion 1- Dyes made into anion of naphthalene sulfonate 0.015 g Methyl ethyl ketone 30 g Megafac F-177 (Dainippon Ink and Chemicals, Inc., fluorine surfactant) 0.05 g

Example 8 In the photosensitive solution B2 of Example 7, N- (p-toluenesulfonyl) acrylimide / acrylonitrile / methyl acrylate / benzyl acrylate copolymer was added to N- (p-
Hydroxyphenyl) methacrylamide / acrylonitrile / methyl methacrylate copolymer (molar ratio 40/30/30,
Weight average molecular weight 45,000) except that phenol novolak was replaced with m, p-cresol novolac (m, p ratio = 6/4, weight average molecular weight 3500, containing 0.5% by weight of unreacted cresol) in Photosensitive solution A3. Example 7
A positive type photosensitive lithographic printing plate 8 was obtained in the same manner as described above.

The planographic printing plates 1 to 8 of Examples 1 to 8
In the two-layered photosensitive layer, the solubility relationships of the respective layers were significantly different when determined under the above-mentioned conditions, and they were provided as upper and lower layers depending on the difficulty of dissolution.

Comparative Example 1 The following photosensitive solution A4 was applied to an aluminum plate which had been subjected to undercoating in the same manner as in Example 1 and dried at 100 ° C. for 2 minutes to obtain a positive photosensitive lithographic printing plate 9. The coating amount after drying is 2.
It was 0 g / m ² .

(Photosensitive Solution A4) m, p-cresol novolak (m, p ratio = 6/4, weight average molecular weight 3500, containing 0.5% by weight of unreacted cresol) 2.3 g naphthoquinone-1,2-diazide- Esterification product of 5-sulfonic acid chloride and 2,3,4-trihydroxybenzophenone (esterification rate 90%) 0.85 g Naphthoquinone-1,2-diazide-4-sulfonic acid chloride 0.01 g The following formula (VII) 0.05 g of tetrahydrophthalic anhydride 0.05 g 4- (p-N, N-diethoxycarbonylaminophenyl) -2,6-bis (trichloromethyl) -s-triazine 0.02 g 4- (p- Hydroxybenzoylaminophenyl) -2,6-bis (trichloromethyl) -s-triazine 0.02 g Victoria Pure Blue BOH pair Dyes whose ions are 1-naphthalenesulfonic acid anion 0.03 g Methyl ethyl ketone 30 g Megafac F-177 (Dainippon Ink and Chemicals, Inc., fluorine-based surfactant) 0.05 g

Comparative Example 2 In the photosensitive solution A4 of Comparative Example 1, m, p-cresol novolac was replaced with N- (p-aminosulfonylphenyl) methacrylamide / acrylonitrile / methyl methacrylate copolymer (molar ratio 45/30/25. A positive photosensitive lithographic printing plate 10 was obtained in the same manner as in Comparative Example 1 except that the weight average molecular weight was changed to 75,000).

Comparative Example 3 In the photosensitive solution A4 of Comparative Example 1, 0.7 g of m, p-cresol novolac was used, and N- (p-aminosulfonylphenyl) methacrylamide / acrylonitrile / methyl methacrylate copolymer (molar ratio) was used. A positive-working photosensitive lithographic printing plate 11 was obtained in exactly the same manner as in Comparative Example 1 except that 1.6 g of 45/30/25, weight average molecular weight 75,000) was added.

Comparative Example 4 A planographic printing plate 5 of Example 5 in which the order of stacking the photosensitive layers was reversed was prepared as follows.

The photosensitive solution C1 of Example 5 was applied to an aluminum plate which had been subjected to undercoating in the same manner as in Example 1, and the temperature was 100 ° C.
For 2 minutes. The coating amount after drying was 0.7 g / m ² . Further, the photosensitive solution A2 of Example 5 was applied and dried to obtain a positive photosensitive lithographic printing plate 12. At that time, the photosensitive liquid A2
After the application, the coating is dried in the drying zone shown in FIG.
Spraying high pressure air of 00mmAg and guide roll 14
Was changed to a heating roll and heating at 130 ° C. was also performed. The total coating amount after drying was 2.0 g / m ² .

[0120]

Embedded image

A positive transparent original image of a line image and a halftone dot image was adhered onto each of the photosensitive layers of the positive type photosensitive lithographic printing plates 1 to 12 of Examples 1 to 8 and Comparative Examples 1 to 4 and carbon of 30 amperes was used. Exposure was performed with an arc lamp from a distance of 70 cm. Each of the exposed photosensitive lithographic printing plates 1 to 12 was subjected to immersion development for 60 seconds at 25 ° C. in an 8 times diluted aqueous solution of DP-4 (developing solution manufactured by Fuji Photo Film Co., Ltd.).

Each of the obtained lithographic printing plates 1 to 11 was printed on a high-quality paper by a KOR type printer manufactured by Heidelberg. When the final number of printed sheets was examined, it was as shown in Table 1.

Next, DP-4 was diluted 10 times and immersion developed at 25 ° C. for 30 seconds. Further, DP-4 was diluted 6 times and subjected to immersion development at 25 ° C. for 30 seconds to change the number of solid steps of gray scale with a density difference of 0.15 (the number of solid steps at 6 times dilution minus the number of solid steps at 10 times dilution). Was evaluated and the development latitude was evaluated. The results are shown in Table 1. The larger the number of printed sheets, the better the printing durability, and the smaller the change in the number of solid steps, the better the development latitude.

[0124]

[Table 1]

As can be seen from Table 1, the photosensitive layer is a layer (A) containing an alkali-soluble novolac resin and a positive-working photosensitive compound, and a water-insoluble and alkaline aqueous solution-soluble acrylic or urethane polymer. The layer is divided into a layer (B) or (C) containing a compound, and when the solubility in the alkaline aqueous solution is higher than that of the layer (A), the layer (B) is a lower layer (B) of the layer (A). When it is low, the photosensitive lithographic printing plate having the layer (C) as the upper layer of the layer (A) is excellent in printing durability and development latitude.

[0126]

According to the present invention, the positive-working photosensitive lithographic printing plate is excellent in printing durability and developing latitude, especially under printing conditions where a plate cleaner is frequently used and when using UV ink. Becomes

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an example of a continuous coating and drying apparatus used in the present invention.

[Explanation of symbols]

 1 1st layer coating material 2 Coating head 3 1st drying zone 4 2nd drying zone 5 Air supply port 6 Exhaust port 7 Air supply port 8 Exhaust port 9 High pressure air generator 10 Heat exchanger 11 Pressure gauge 12 High pressure air blowing nozzle 13 Guide Roll 14 Guide Roll 15 Guide Roll 16 Guide Roll 17 Guide Roll 18 Air Flow Adjustment Damper 19 Air Flow Adjustment Damper

Claims (2)

[Claims] 1. A support having a layer (A) containing an alkali-soluble novolac resin and a positive-working photosensitive compound, wherein an alkaline aqueous solution is soluble between the layer (A) and the support. Positive photosensitive lithographic printing plate comprising a layer (B) containing a high molecular compound and more easily dissolved in an alkaline aqueous solution than the layer (A). 2. A support is provided with a layer (A) containing an alkali-soluble novolac resin and a positive-working photosensitive compound, and the layer (A) is provided with a polymer compound soluble in an alkaline aqueous solution. A positive photosensitive lithographic printing plate comprising a layer (C) which is contained and is less soluble in an alkaline aqueous solution than the layer (A).