JP2608134B2 - Lithographic printing materials - Google Patents

Description

The present invention relates to a lithographic printing material, and in particular, as a support, gelatin in a subbing layer for increasing the adhesion to a hydrophilic photographic layer. A lithographic printing material having a backing layer using a polyester film containing

(B) Prior art and its problems Lithographic printing materials utilizing the DTR method, more specifically, at least one photosensitive layer on a support, on which the image recorded in the photosensitive layer by inversion, transfer recording should be performed. A lithographic printing material obtained by exposing a material having a layer of a physical development nucleus to an image, performing a silver diffusion transfer development process, and forming a metallic silver image on the outer surface of the material is called a direct plate making method. For example, Japanese Patent Publication Nos. 48-30562, 51-15765 and 51-16
803, JP-A-51-111103, JP-A-52-150105, JP-A-53-9603,
54-135002, 55-7704, 56-27151, 57-8683
5, 63-228167, and the like, and in recent years, the printability has been remarkably improved.

On the other hand, various supports are described in the above series of patent publications, but with the improvement of printability, a plastic film is used as the support due to problems such as plate elongation during printing, or soaking of moisture. However, polyester films are mainly used because of their excellent mechanical properties, dimensional stability, heat resistance, chemical resistance, transparency and the like.

However, as is well known, polyester films generally have high crystallinity, are chemically inert, and have high chemical resistance.
Further, polyester films are conventionally subjected to undercoating for the purpose of obtaining good adhesion to a hydrophilic photographic layer which is extremely hydrophobic because of not having hydrophilicity.

There are roughly two methods for undercoating.
One is the so-called `` solvent undercoating method '' in which a composition comprising an organic material and an organic copolymer to be a swelling or dissolving agent for a polyester film is applied, for example, US Pat.
And British Patent Nos. 772,600, 776,157 and 785,789, and JP-A-50-1718 and 50-825.

On the other hand, there is a so-called "aqueous undercoating method" in which an organic copolymer is applied in the form of an aqueous composition (latex) substantially free of an organic solvent, for example, Japanese Patent Publication Nos. 44-13278 and 45-10988.
No., JP-A-49-11118, JP-A-51-27918, JP-A-52-114670
No. 54-11177, No. 55-67745, No. 58-169145,
Nos. 59-77439 and 63-253352.

The aqueous undercoating method generally includes a two-layer undercoating method in which a first layer is coated with a latex layer and a second layer is coated with a gelatin layer, and a one-layer undercoating method in which latex and gelatin are mixed and coated.

The solvent undercoating method is shifting to the aqueous undercoating method due to the deterioration of the physical properties of the polyester film during the undercoating process, or the problem of work safety and health or pollution caused by the gas of the organic solvent.

Generally, a printing material using a polyester film (hereinafter referred to as "PET base") as a support has a gelatin binder mainly on the opposite side of the silver halide emulsion layer for the purpose of antistatic, curling prevention and sticking prevention. It has a backing layer.

A backing layer is usually applied to the PET base prior to coating the silver halide emulsion layer on the PET base. The PET base on which the backing layer is applied and dried is rolled up in a roll,
Next, it is stored in a roll state until a silver halide emulsion layer or the like is coated on the surface opposite to the backing layer (hereinafter referred to as “surface”). The length of one roll varies depending on the thickness of the PET base, and is usually 75 to 200 μm and is usually 1000 to 3000 m.

The period from the application of the backcoat layer to the application of the silver halide emulsion layer or the like to the surface of the PET base on which the backcoat layer has been applied depends on various conditions, for example, production amount, application rate of the backcoat layer, backcoating. The same coating liquid is continuously applied from the viewpoint of productivity, although it varies depending on the amount per one layer coating liquid dissolving batch and the number of dissolving batches required for one continuous coating (hereinafter referred to as "one cycle"). It is more efficient to apply a large amount, and usually, one cycle of the backcoat layer is applied, and then one cycle of the silver halide emulsion layer or the like is applied to the surface of the PET base coated with the backcoat layer. .

The application length of one cycle varies depending on the amount of production, but ranges from one batch of coating solution dissolution to several batches. It is better to increase the amount of one batch of dissolution from the viewpoint of work efficiency.
The time required for coating per dissolving batch is generally 5 to 20 hours in view of the size of the dissolving vessel and the stability of the coating solution over time.

In general, it takes one day to several weeks from the application of the backing layer for one cycle to the application of the silver halide emulsion layer or the like to the surface of the PET base on which the backing layer has been applied.

In addition, from the viewpoint of yield, it is necessary to always secure a PET base coated with a backcoat layer in excess of the amount required to apply a silver halide emulsion layer or the like in one cycle. The base is used to coat the next cycle of the silver halide emulsion layer and the like. For this reason, the PET base coated with the backcoat layer may be stored in a roll form for one month or more.

The backing layer mainly uses gelatin as a binder, and also uses a hardening agent, a surfactant, and if necessary, a matting agent, an antistatic agent, an antihalation agent, and the like.

Examples of the hardener include aldehyde hardeners such as formaldehyde, glyoxal and glutaraldehyde, vinyl sulfone hardeners, epoxy hardeners, and aziridine hardeners. PE containing
When an aldehyde-based hardener is used for the backing layer of a lithographic printing material having a T base as a support, a silver halide emulsion is applied to the surface of the PET base coated with the backing layer after applying the backing layer. Until the layer or the like is applied, the diffusion of formalin gas, which is a property unique to the aldehyde hardener, causes a phenomenon that the gelatin in the undercoat layer on the surface in contact with the backing layer is hardened. The longer the period of contact with the backing layer, the harder the gelatin in the undercoat layer on the surface, and the greater the film strength of the entire undercoat layer.

When the film strength of the undercoat layer on the surface is improved, there arises a problem that the adhesion between the silver halide emulsion layer or the like coated thereon and the undercoat layer is significantly reduced.

In recent years, the printability of lithographic printing materials has been considerably improved, and when the number of prints is increased, or when printed with a special ink, for example, ultraviolet curing ink, chipping of metallic silver, fire, or water retention. Before printing becomes a problem, a so-called "film peeling" occurs in which the photographic layer peels off from the support during printing.
This causes serious problems that make printing impossible.

The aldehyde-based hardener promotes the hardening of the emulsion layer in contact with the backing layer due to the diffusion of formalin gas, as described above, and causes deterioration of photographic characteristics and printability over time.

(C) Object of the Invention A first object of the present invention is to provide a lithographic printing material having a backing layer using a polyester film containing gelatin in a subbing layer as a support, wherein the lithographic printing plate does not cause the aforementioned film peeling. It provides printing materials.

A second object of the present invention is to provide a lithographic printing material in which the photographic properties and printability of the lithographic printing material are less deteriorated with time.

(D) Constitution of the Invention An object of the present invention is to provide a lithographic printing material having a backing layer using a polyester film containing gelatin in a subbing layer as a support. Achieved by using a membrane agent.

The undercoat layer of the polyester film in the present invention is a layer previously applied to the polyester film in order to increase the adhesiveness with the hydrophilic photographic layer, and is roughly classified as described above. There is a law. The solvent undercoating method is shifting to the aqueous undercoating method due to the deterioration of the physical properties of the polyester film during the undercoating process, or the problems of safety and hygiene in operation due to organic solvent gas and pollution.

In the aqueous subbing method, latex and gelatin are usually applied.

As the gelatin contained in the undercoat layer in the present invention, those commonly used in the art, such as lime-processed gelatin, acid-processed gelatin, phthalated gelatin, gelatin such as gelatin derivatives such as acylated gelatin, etc. And any of them can be used.

The backing layer in the present invention is coated on the side opposite to the silver halide emulsion layer for the purpose of preventing static charge, curling and sticking. Gelatin is mainly used as the binder in the backing layer, but a part of gelatin may be replaced with a water-soluble polymer such as polyvinyl alcohol. As the gelatin, any of those commonly used in the art such as lime-processed gelatin, acid-processed gelatin, gelatin such as phthalated gelatin, and acylated gelatin as described above can be used.

Non-aldehyde hardeners used in the backing layer in the present invention include divinylsulfone N, N'-ethylenebis (vinylsulfonylacetamide), 1,3-bis (vinylsulfonyl) -2-propanol, Methylene bismaleimide, 5-acetyl-1,3-diacryloyl-hexahydro-S-triazine, 1,3,5-triacryloyl-hexahydro-S-triazine, 1,3,5-trivinylsulfonyl-hexahydro-S- Active vinyl compounds such as triazine.

2,4-dichloro-6-hydroxy-S-triazi sodium salt, 2,4-dichloro-6-methoxy-S-triazine, 2,4-dichloro-6- (4-sulfoanilino)
-S-triazine sodium salt, 2,4-dichloro-6
-(2-sulfoethylamino) -S-triazine, N-
Active halogen compounds such as N'-bis (2-chloroethylcarbamyl) piperazine.

Bis (2,3-epoxypropyl) methylpropylammonium / p-toluenesulfonate, 1,4-bis (2 ', 3'-epoxypropyloxy) butane, 1,3,5
Epoxy compounds such as triglycidyl isocyanurate and 1,3-diglycidyl-5- (γ-acetoxy-β-oxypropyl) isocyanurate.

Ethyleneimino compounds such as 2,4,6-triethylene-S-triazine, 1,6-hexamethylene-N, N'-bisethyleneurea and bis-β-ethyleneiminoethylthioether.

Methanesulfonic acid ester compounds such as 1,2-di (methanesulfonoxy) ethane, 1,4-di (methanesulfonoxy) butane, and 1,5-di (methanesulfonoxy) pentane.

Dicyclohexylcarbodiimide, 1-cyclohexyl-3- (3-trimethylaminopropyl) carbodiimide-p-toluenesulfonate, 1-ethyl-3-
Carbodiimide compounds such as (3-dimethylaminopropyl) carbodiimide hydrochloride. Isoxazole compounds such as 2,5-dimethylisoxazole perchlorate, 2-ethyl-5-phenylisoxazole-3'-sulfonate, and 5,5 '-(paraphenylene) bisisoxazole.

 Inorganic compounds such as chrome alum and chromium acetate.

N-carbethoxy-2-isopropoxy-1,2-dihydroquinoline, N- (1-morpholinocarboxy)-
Dehydration-condensed peptide reagents such as 4-methylpyridinium chloride; active ester compounds such as N, N'-adipoyldoxydisuccinimide and N, N'-terephthaloyldioxydisuccinimide.

Isocyanates such as toluene-2,4-diisocyanate and 1,6-hexamethylene diisocyanate can be mentioned.

Aldehyde hardeners that cannot be used in the backing layer in the present invention include those that produce formalin and formalin as a dispersion, such as mucochromic acid, mucobromic acid, mucophenoxycyclolic acid, Phenoxybromic acid, formaldehyde, dimethylolurea, trimethylolmelamine, glyoxal, monomethylglyoxal, 2,3-dihydroxy-1,4-dioxane, 2,3-dihydroxy-5-methyl-
Aldehyde compounds such as 1,4-dioxane succinaldehyde, 2,5-dimethoxytetrahydrofuran, glutaraldehyde and derivatives thereof are available.

The amount of the hardening agent added to the backing layer is usually 0.
It is used in the range of 01 to 100% by weight, preferably 0.1 to 10% by weight. For the adhesion amount of gelatin to maintain curl balance, is influenced by the amount of gelatin in Table coating layer containing a silver halide emulsion layer, used in the range of usually 0.1 to 20 g / m ^2, preferably from 1 to 10 g / m Used in the range of ² .

In the backing layer, besides gelatin, hardener and surfactant,
If necessary, a matting agent, an antihalation agent, an antistatic agent and the like can be used.

As the lithographic printing material in the present invention, for example,
No. 63-228167, in which an undercoat layer, a silver halide emulsion layer and an image receiving layer containing physical development nuclei are sequentially coated on the surface of the polyester film coated with a back coating layer.

The lowermost undercoat layer on the surface is disclosed in JP-A-48-5503 and JP-A-48-1002.
03, 49-55402, 53-21602 or 53-9603, an undercoat layer using gelatin as a hydrophilic polymer, and various gelatins can be used as gelatin. , And a part of gelatin
It can be replaced with a hydrophilic colloid, sodium alginate, PVA, PVP, etc. described in -100554. Further, the undercoat layer may also serve as an antihalation layer, and further, various activators, hardeners, matting agents and additives usually used in the art may be used as necessary.

As the silver halide emulsion layer, any of those known in the art can be used, and preferred are those described in JP-A-49-55402.

Physical development nuclei are also disclosed in JP-B-48-30562, JP-A-49-55402,
All those described in JP-A-53-21602 are used.

The lithographic printing material of the present invention is generally treated with an alkali developing solution after image exposure, and subsequently, if necessary, subjected to plate making and printing treatment with a neutralizing solution, a fixing solution, a desensitizing solution, a humidifying solution, and the like. However, the developer is also an ordinary photographic alkali developer containing a developing agent such as hydroquinone, or the developer is contained in the material, and the developing solution contains substantially no developing agent.
Any one such as a so-called alkaline activated developer can be used. Compounds for various purposes are added to these developers. For example, JP-B-51-486, JP-A-52-150105, and the like.

Various processing solutions known to those skilled in the art can be used for the composition of neutralizing, fixing, desensitizing, etching or humidifying liquids and the like used in the present invention, depending on the purpose and type of plate material.

(E) Examples Hereinafter, the present invention will be described with reference to Examples, but the present invention is not limited thereto.

Example 1 <Back coating solution A> Gelatin 30 g Formalin (12% aqueous solution) 3 cc Matting agent 2 g Saponin (10% aqueous solution) 10 cc Add water to make the total amount 500 g.

<Back coating solution B> Gelatin 30 g 2,4-Dichloro-6-hydroxy-S-triazine sodium salt (10% aqueous solution) 10 cc Matting agent 2 g Saponin 10 cc Add water to make the total amount 500 g.

The above-mentioned back coating solutions A and B were applied at a coating amount of 50 g / m ² to a polyester film having an aqueous subbing layer containing latex and gelatin, dried, and wound up in a roll.

After the back coating, the film was placed in a roll at a temperature of 25 ° C. and a relative humidity of 55% for 1 day and 10 days in a roll state, and then an undercoat solution shown below was applied on the surface at a coating amount of 60 g / m ² .

<Undercoat solution> Gelatin 30 g 2,4-Dichloro-6-hydroxy-S-triazine sodium salt (10% aqueous solution) 13 cc Sorbitol polyglycidyl ether (10% methanol solution) 4.5 cc Matting agent 10 g Carbon black dispersion ( 5cc saponin 10cc Add water to make the total amount 600g.

A high-contrast silver chloride emulsion sensitized in the form of an undercoat layer was coated with silver nitrate at 1.5 g / m ² . After drying and heating at 40 ° C. for 3 days, a physical development nucleus layer was applied as described in JP-A-55-14645, image exposure was performed, and a development neutralization treatment was performed according to the above-mentioned publication. After drying, a printing plate is obtained.

As described in JP-A-56-6237, the printing plate is prepared by using a desensitizing liquid and a humidifying liquid, and using AB Dick 350CD (trademark of offset printing machine manufactured by AB Dick).
Printing using a printing machine.

As the printing ink, a normal black ink and an ultraviolet curing ink were used as special inks, and the ratio of film peeling at the number of prints was evaluated. The results are shown in Tables 1 and 2.

As shown in the above results, when an aldehyde-based hardener such as formalin is used for the backcoat layer, the aging period from application of the backcoat layer and drying to application of the undercoat layer and the emulsion layer on the surface is reduced. Even in one day, film peeling occurs partially when the number of printed sheets reaches 20,000 or more.

When the aging period is 10 days or more, the adhesiveness further decreases, and 20
Partial film peeling or full surface film peeling occurs with 000 sheets or more.

(F) Effect of the Invention As is apparent from the results of the examples, in a lithographic printing material having a backing layer using a polyester film having a gelatin-containing subbing layer as a support, a non- By using aldehyde hardener,
No film peeling in multi-sheet printing or special ink printing.

In the lithographic printing material of the present invention, deterioration of photographic characteristics and printability over time was considerably reduced as compared with the conventional one.

Claims (1)

(57) [Claims] 1. A lithographic printing material having a backing layer using a polyester film containing gelatin in a subbing layer for increasing the adhesion to a hydrophilic photographic layer as a support. A lithographic printing material characterized by using a non-aldehyde hardener for the layer.