DE2107901B2 - PRINTING PLATE - Google Patents

Description

The invention relates to a printing plate having a sensitive layer on the surface a water-insoluble, hydrophilic acrylic resin layer.

Most common printing plates are aluminum matting with mechanically roughened or chemically : treated surface on which, for example, gelatin, polyvinyl alcohol or albumins together with a photosensitive material such as chromates and diazo compounds. The plates are finally dried, exposed through a film negative placed above the plate, developed and treated again. The photosensitive hardened parts of the lines and images absorb, conditionally due to the lipophilic properties, good printing ink. On the other hand, the exposed surface absorbs the aluminum plate in developing water and

ίο rejects printing ink. When using such Plate in the offset process, the exposed surface of the aluminum plate becomes through the permanent Friction with the hardened parts and lines gradually thin. In some cases, the will wear out Lines and images bound and reinforced by lacquer-like materials. The surface of the aluminum plate, in particular their mechanically roughened surface tends to be “sometimes lighter than that wear out photosensitive hardened layer. if

As the surface wears away, the damaged plate gives indistinguishable images with less hydrophilic function and ultimately you can no longer print. Furthermore, the water requirement must be the mechaniscii roughened aluminum surface suitable to get clear images and setting the need for water is difficult.

It was already known, planographic printing plates produce, in which the base plate has been provided with a pigment-containing coating layer, in which was a mixture of a hydrophilic colloid and a crosslinking agent as a binder (U.S. patent 30 55 295). Suitable binders were polyvinyl alcohol, oxidized corn starch, guar gum and various other natural products as well as polyacrylamide are used.

The invention is based on the object of a new printing plate with an exceptionally long printing time produce, which brings a simplification of the exposure process with it. This task will solved according to the invention in that between the base plate and the photosensitive layer a Intermediate layer made of a hydrophilic polymer is arranged, the particularly balanced hydrophilic Has properties.

The invention is based on a pressure plate, which consists of a base plate, one applied to it Layer of a hydrophilic polymer and a photosensitive layer arranged on this layer consists, and is characterized in that the layer of the hydrophilic polymer consists of a water-insoluble hydrophilic acrylate or methacrylate homopolymers or copolymers is formed, the has a water absorption of at least 20% of its weight.

Base plates used as the output pressure plate in the present invention are metal plates, such as a steel, tin or zinc plate, a stainless steel plate, etc., plastic plates, such as a polyethylene terephthalate plate, polystyrene plate, acetyl cellulose plate, hydrophilic acrylic resin plate etc. and paper.

It is necessary that the hydrophilic acrylate resin or methacrylate resin constituting the hydrophilic layer form, are insoluble in water.

The hydrophilic acrylate resins should absorb at least 20% of their weight water, but preferably absorb no more than about 120% of their weight water.

That is preferred in the hydrophilic acrylate or Hydrophilic monomers present in methacrylate resins are, in particular, a hydroxy-lower alkyl acrylate or Hydroxy lower alkyl methacrylate, e.g. B. 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl imethacrylate, 3-hydroxypropyl acrylate 3-hydroxypropyl methacrylate, Dipropylene glycol monomethacrylate and Dipropylene glycol monoacry lat.

The preferred monomers are hydroxyalkyl acrylates and hydroxyalkylmeihacrylates, especially 2-hydroxyethyl methacrylate.

Likewise, copolymers of these monomers with one another or with other mischpoK-merisable Monomers are present.

If the hydrophilic monomer gives a product that is water soluble, it is necessary to have a copolymerizable one To use monomer to make it only swellable in water and not water-soluble do. The copolymerizable monomer can be used in an amount of 0.05 to 50%. Preferred comonomers are methyl acrylate, ethyl acrylate, Isopropyl acrylate, propyl acrylate, butyl acrylate, sec-butyl acrylate, pentyl acrylate, 2-thionylhexyl acrylate, Methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, sec-butyl methacrylate, pentyl methacrylate, lower alkoxyethyl acrylate and lower alkoxyethyl methacrylate, for example methoxyethyl acrylate, methoxyethyl methacrylate, Ethoxyethyl acrylate and ethoxyethyl methacrylate, triethylene glycol acrylate, triethylene glycol methacrylate, Glycerol monoacrylate and glycerol monomethacrylate.

Unsaturated amines, p-amino-styrene, o-aminostyrene, 2-amino-4-vinyltoluene, alkylaminoalkyl acrylate can also be used and methacrylate, for example diethylaminoethyl acrylate, diethylaminoethyl methacrylate, Dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, tert-butylaminoethyl acrylate, tert-butylaminoethyl methacrylate, Piperidinoethyl acrylate, piperidinoethyl methacrylate, morpholinoethyl acrylate, morpholinoethyl methacrylate, 2-vinylpyridine, 3-vinylpyridine, 4-vinylpyridine, 2-ethy! -5-vinylpyridine, dimethylaminopropyl acrylate, Dimethylaminopropyl methacrylate, dipropylaminoethyl acrylate, dipropylaminoethyl methacrylate, di-n-butylaminoethyl acrylate, di-n-butylaminoethyl methacrylate, di-sec-butylaminoethyl acrylate, di-sec-butylaminoethyl methacrylate, dimethylaminoethyl vinyl ether, Diethylaminoethyl vinyl sulfide, diethylaminoethyl vinyl ether, amino ethyl vinyl ether, Aminoethylvinylsulfid, Monomethylaminoäthylvinylsulfid, Monomethyiaminoäthylvinyläther, N- (γ-Monomethylamino) -propylacrylamid, N (/? - Monomethylamino) ethyl acrylamide, N - (/? - Monomethylamino) ethyl methacrylamide, 10-aminodecyl vinyl ether, 8-amino octyl vinyl ether, 5-aminopenty vinyl ether, 3-aminopropyl vinyl ether, 4-aminobutyl vinyl ether, 2-aminobutyl vinyl ether, Monoethylaminoethyl methacrylate, N- (3,5,5-trimethylhexyl) -aminoethyl vinyl ether, N-cyclohexylaminoethyl vinyl ether, 2- (l, l, 3,3-tetramethylbutylamino) ethyl methacrylate, N-tert-butylaminoethyl vinyl ether, N-methylamino-ethyl vinyl ether, N-2-ethylhexylaminoethylvinylether, N-tert.-butylaminoethylvinylether, N-tert-octylaminoethyl vinyl ether, 2-pyrrolidinoethyl acrylate, 2-pyrrolidinoethyl methacrylate, 3- (dimethylaminoethyl) -2-hydroxypropyl acrylate, 3- (dimethylaminoethyl) -2-hydroxypropyl methacrylate, 2-aminoethyl acrylate, 2-aminoethyl methacrylate to be refused. The presently preferred amino compounds are alkylaminoethyl acrylates and alkylaminoethyl methacrylates, most preferred is tert-butylaminoethyl methacrylate.

The networking tool! is preferably in amounts of 0.1 to 2.5%, more preferably in amounts of not greater than 2.0%, although 0.05 to 15% or even 20% crosslinking agents can be used. It

Of course, care should be taken to ensure that the crosslinking agents are not used in an amount that does not allow the product to absorb at least 20% water.
Typical examples of crosslinking agents are ethy-

lenglycol diacrylate, ethylene glycol dimethacrylate, 1,2-butylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, propylene glycol diacrylate, Propylene glycol dimethacrylate, diethylene glycol dimethacrylate, Dipropylene glycol dimethacrylate,

ao diethylene glycol diacrylate, dipropylene glycol diacrylate, DivinylbenzoJ, DivinyJtoluoJ, diallyl tartrate, allylpyruvate, Allyl maleate, divinyl tartrate, triallyl malamine, N, N'-methylene-bis-acrylamide, Glycerin trimethacrylate, diallyl maleate, divinyl ether, diallyl monoethylene glycol

citrate, ethylene glycol vinyl allyl citrate, allyl vinyl maleate, Diallyl itaconate, ethylene glycol diester of itaconic acid, divinyl sulfone, hexahydro-1,3,5-triacryltriazine, triallyl phosphite, Diallyl ester of benzenephosphorous acid, polyester of maleic anhydride and triethylene glycol, Polyallyl glucose, for example triallyl glucose, Polyallylsucrose, for example pentallylsucrose, Sucrose diacrylate, glucose dimethacrylate, pentaerythritol tetraacrylate, sorbitol dimethacrylate, diallylaconitate, Divinyl citraconate, diallyl fumarate.

Ethylenically unsaturated acids or their salts can also be used, such as acrylic acid, Cinnamic acid, carotonic acid, methacrylic acid, itaconic acid, Aconitic acid, maleic acid, fumaric acid, mesaconic acid and citraconic acid. As was shown before partial esters such as mono-2-hydroxypropyl itaconate, mono-2-hydroxyethyl itaconate, mono-2-hydroxyethylcitraconate, Mono-2-hydroxypropylaconitate, mono-2-hydroxyethyl maleate, mono-2-hydroxypropyl fumarate, Mono-methyl itaconate, mono-ethyl itaconate, mono-methyl cellosolve ester of itaconic acid (Methyl cellosolve is the monomethyl ether of diethylene glycol), mono-methyl cellosolve ester of maleic acid be used.

The polymers can be used as casting syrups, as aqueous dispersions, by aqueous suspension polymerization or as solutions in organic solvents such as ethyl alcohol, methyl alcohol, propyl alcohol, isopropyl alcohol, Formamide, dimethyl sulfoxide or other suitable solvents.

The polymerization can be carried out at 20 to 150 ° C., frequently at 35 to 90 ^° C., and can be completed after use as a ship coating. The polymerization can be carried out using a radical catalyst in an amount of 0.05 to 1% based on the polymerizable monomer. Typical catalysts are tert-butyl peroctoate, benzoyl peroxide, isopropyl percarbonate, 2,4-dichlorobenzoyl peroxide, methyl ethyl ketone peroxide, cumene hydroperoxide and di-

cumyl peroxide. Irradiation, for example by ultraviolet light or y-rays, can also can be used to catalyze the polymerization.

The hydrophilic polymers are available as a solution, as a pouring syrup or as a film that is applied to the surface of the Base plate with the help of painting, pouring, gluing and the like with and without the use of adhesives are applied, and form a water-insoluble hydrophilic resin layer. The strength of the hydrophilic resin layer is generally 5 to 300 µm, preferably 10 to 50 µm. By applying A water-insoluble hydrophilic resin layer on the surface of the base plate can give good results in terms of the dimensional stability of the hydrophilic layer or printing plate, in terms of its Attachment to the printing machine and the like. Since the hydrophilic resin is transparent, will the printing plate is completely transparent if a transparent plastic plate is used as the base plate will. This is an advantage in that recording is easier in multi-color printing.

Further, the hydrophilic resins can be used to form a layer having an increased mechanical strength ao as well as adhesion to the base plate, oxidizing hardeners are incorporated, such as sodium, Potassium or ammonium chromate or dichromate, aminol paste resins such as melamine resin, benzoguanamine resin or acetoguanamine resin, acid anhydride, such as maleic anhydride, citraconic anhydride. Succinic anhydride, phthalic anhydride, trimellitic anhydride, _ pyromellitic anhydride and the like, polyamines, such as ethylene diamine, propylene diamine, diethylene triamine, tetraethylene pentamine, piperazine, Pyrazine, m-xylenediamine, p-xylenediamine, m-phenylenediamine, p-phenylenediamine, benzidine, diaminodiphenylmethane, diaminodiphenylsulfone, 3,3'-dichloro-4,4'-diphenylmethanediamine, Naphthalenediamine and the like.

The amount of curing agents added to the hydrophilic resin is generally less than 2 percent by weight, preferably 0.1 to 0.5 percent by weight.

The mechanical strength of the hydrophilic resin layer, however, increases when the hardening agent is added, while the hydrophilic properties sometimes lose weight. In such a case, finely divided powdered materials are preferred to hydrophilic Add resin. Such an addition provides sufficient hydrophilic properties reached for the printing plate. Such powdered materials are finely divided powdered inorganic ones Materials, for example silicon dioxide, aluminum dioxide, magnesium oxide, zirconium oxide, barium sulfate, acid clay, active clay, talc and diatomaceous earth. Preferred materials are silica and alumina. The amount of powdered materials to the hydrophilic resin is less than 5 percent by weight, preferably 0.5 to 2 percent by weight. As compounds that have a photosensitive Layer of the present invention, photosensitive compositions are used, composed of vinyl monomers, photosensitizers, and resins such as an unsaturated polyester resin, Alkyd resin, acrylic urethane resin, silicone modified acrylic resin, polybutadiene and cellulose, photosensitive Polymers modified by compounds such as diazo compounds, azide compounds, organic sulfur Compound compounds and cinnamic acid compounds, and mixtures consisting of dichromates and composed of gelatin, polyvinyl alcohol and albumin. In terms of printing capacity and durability, acrylic urethane resins are particularly superior to others.

The above-mentioned polymeric materials are dissolved in organic solvents that have the property have to swell or partially dissolve the hydrophilic layer, for example alcohols, ketones and Ester, and applied to the surface of the hydrophilic resin layer by coating and drying. In such a case, the surface of the hydrophilic resin layer swells or partially dissolves and mixes with photosensitive compounds and both layers are glued together. The so obtained printing plate is exposed to a negative film, developed, washed with water and dried and, if necessary, absorbs water. Then it is applied to the offset printing machine and used for offset printing. It gives excellent results. When the hydrophilic layer is relatively thick, the water requirement can be kept extremely small by a spray roller will.

In the present invention, a metal plate coated with a water-insoluble hydrophilic resin, Plastic plate, paper and the like are used in place of the usual aluminum plate. Therefore, if the If the hydrophilic resin layer is worn away, the lithographic printability does not become perfect made impossible as long as the hydrophilic layer exists. The print capacity and durability gain weight very much. Because although only less than 20,000 sheets of paper by using the conventional aluminum plate (with albumin and mechanically roughened) can be made is it is surprising that more than 100,000 sheets of paper using the printing plate according to the present invention Invention can be printed.

Another effect of the present invention is that only a small amount of water is required for the lithographic printing is necessary. The hydrophilic resin layer releases the absorbed water slowly and constantly free and it is possible to get by with only a small amount of water. So it won't be excessive The amount of water is transferred to the printing paper and the printing accuracy decreases without stretching the Paper size increases considerably. These properties also help make the printing process easier, without the need for water to be checked by a specialist.

As mentioned above, the printing plate features a photosensitive layer on the hydrophilic resin layer very big advantages compared to the conventional printing plate with a photosensitive Layer directly on the aluminum plate and is very favorable because of the increased durability of the printing and printing accuracy and because of the easy printing process.

The invention can be better understood in connection with the drawing.

Fig. 1 shows a partial cross section of the printing plate according to the invention and

Figure 2 shows a partial cross-section of the printing plate after exposure and development.

With regard to the details of the drawing it should be noted that the output pressure plate consists of a Base plate 1, a layer 2 of water-insoluble hydrophilic acrylic resins applied to the plate 1 and a photosensitive layer 3 applied to layer 2.

O MSt

The thickness of layers 2 and 3 are very over-rubbed drawn for the sake of explanation.

Unless otherwise specified in the description and claims, all parts are and Percent parts by weight and percent by weight.

example 1

400 parts of polyethylene glycol-400 becomes 360 Parts of tolylene diisocyanates are added and reacted with heating at 140 ° C. for 30 minutes and cooled; then 260 parts of 2-hydroxyethyl methacrylate are added and 0.21 part of p-benzoquinone was added to the reactant and kept at a temperature of 40 ° C Reacted for 24 hours to obtain unsaturated acrylic urethane resin (I). The resin (1) was a very viscous liquid at room temperature. The photosensitive resin mixture was obtained by adding 50 parts of the Resin (I) with 50 parts of commercially available cellulose phthalate, 1 part of benzoin ethyl ether and 100 parts Acetone were mixed.

Example 2

The 79.6% 2-hydroxyethyl methacrylate, 0.3% Ethylene glycol dimethacrylate, 20% glycerol and 0.1% diethyl percarbonate existing solution was in the Space poured between two glass plates, adjusted by a spacer to a 0.15 mm gap to be carefully maintained and so as not to form bubbles. The mixture was polymerized by a temperature of 65 C was maintained for 20 min, then a transparent plate was obtained, by removing the plates. The glycerol was then washed with distilled water extracted and further at room temperature at a relative humidity of 40% and a temperature dried at 25 C for 24 hours to obtain a hydrophilic resin plate. The plate was on a 0.15 mm thick aluminum plate glued using an adhesive mixture of an epoxy and polyamide resin. The other side of the resin plate was evenly coated with a photosensitive resin mixture coated, which was obtained in Example 1, so that the thickness of the dry film is about 2 μ. It was then dried to obtain the printing plate.

After the negative film was placed on the printing plate, the plate was placed in the vacuum pressure chamber placed and exposed to a high pressure mercury lamp at a distance of 35 cm for 1 min; then was with a 1% aqueous ethanolamine solution developed, washed with water and dried to obtain the printing lithograph. The offset printing was carried out using lithography. The printing effects were very good obtained with good discernment and good dimensional accuracy. It is also possible to have more than Printing 100,000 sheets of paper per plate and checking the water consumption is easier than after that conventional method.

Example 3

The hydrophilic monomer solution of Example 2 was applied to the 0.15 mm thick aluminum plate, which was previously coated with a 10 μ thick primer mixture made of an epoxy-polyamide resin had been. The thickness of the hydrophilic resin is about 0.2 mm. It was made under a nitrogen atmosphere under the same conditions as

polymerized in Example 2. Then the lithography was prepared for printing and the offset printing executed. The same good results as in Example 2 were obtained.

Example 4

A hydrophilic resin plate obtained in Example 2 was placed on the surface of a 0.2 mm Polyethylene terephthalate glued with the help of an epoxy adhesive and the other surface of the Resin plate with a diazo compound "Fuji Super-Resist", a commercial product of Fuji Chemicals Co., Ltd., coated to a thickness of 3 µm, exposed to the negative film and as previously described treated to obtain a printing plate. Four color offset printing was used of the printing plate and the good results obtained as in Example 2. The recording too each record became easy and quick because of

as their permeability.

Example 5

1.0 g of xylene, 100 g of 2-hydroxyethyl methacrylate and 0.33 g of isopropyl percarbonate were placed in a flask equipped with a stirrer and a heating mantle. The flask was ^{stirred rapidly at 100 °} C. under a nitrogen atmosphere. After 15 minutes the slurry was filtered off hot and the polymer isolated. The polymeric powder was reslurried in 300 ml of xylene, filtered and dried. A 98% yield of an alcohol-soluble powder (particle size 2 to 5 μ) was obtained. 100 g of the polymeric powder were dissolved in 200 ml of methanol, then 0.2 g of epoxy resin and 1.5 g of finely divided silicon dioxide powder were added and dispersed homogeneously. The solution thus obtained was applied to a primer mixture of epoxy-polyamide resin previously applied to a 0.15 mm thick steel plate to become 10μ thick so that the dried layer had a thickness of 20μ, and dried. The lithography was then prepared for printing and offset printing was carried out. The same good results as in Example 2 were obtained. The mechanical strength of the hydrophilic resin layer was good.

Example 6

A pouring syrup was made from 100 g of 2-hydroxyethyl acrylate, 0.2 g of ethylene glycol diacrylate prepared and

0.4 g of tert-butyl peroctoate, 1 g of ethylenediamine and 1 g of finely divided aluminum oxide powder were added to the syrup and homogeneously dispersed. The syrup was placed on a thin plate so that the dried Thickness was 30 μ. Then the litho-

graphic for printing produced and carried out the offset printing. It got the same good results as obtained in example 2. The mechanical strength of the hydrophilic resin layer was very good.

Example 7

A pouring syrup was made from 100 g of 2-hydroxyethyl methacrylate, 0.2 g of ethylene glycol dimethacrylate produced and 0.4 g of tert-butyl peroctoate, 0.2 g of potassium dichromate and 2 g of finely divided silica powder added to the syrup and dispersed homogeneously. Dei Syrup was applied to an aluminum plate so that the dried starch was 25 µ. Then became the lithograph prepared for printing and there;

509 584/35

2

Room / 901

Offset printing carried out. The same good results as in Example 2 were obtained. the mechanical strength of the hydrophilic resin layer was very good.

Example 8

7.5 l of ethanol, 100 g of tert-butylaminoethyl methacrylate, 150 g of n-isopropyl acrylamide and 2.55 kg 2-hydroxyethyl methacrylate (the 0.3% ethylene glycol dimethacrylate contained) were placed in a kettle together with 10 g of tert-butyl peroctoate and the

The solution was heated to 85 ° C. for 7 hours in order to carry out the polymerization to a conversion of 90 ". 0.25 g Maleic anhydride and 1 g of finely divided silica powder were added to the polymer thus obtained added and dispersed homogeneously. The solution was applied to an aluminum plate so that the dried starch was 35 μ. Then the lithography was prepared for printing and the offset printing executed. The same good results as in Example 2 were obtained. The mechanical The strength of the hydrophilic resin layer was very good.

1 sheet of drawings

Claims (10)

Patent claims: 1. Printing plate, consisting of a base plate and a hydrophilic layer applied to it Polymers and a photosensitive layer arranged on this layer, thereby characterized in that the layer of the hydrophilic polymer consists of buckets of water-insoluble hydrophilic acrylate or methacrylate homopolymers or copolymers is formed, the one Has water absorption of at least 20% of its weight. 2. Printing plate according to claim 1, characterized in that the hydrophilic acrylate or Methacrylate homopolymers or copolymers of hydrophilic hydroxy-lower alkyl acrylate and / or Hydroxy-lower alkyl methacrylate and / or hydroxy-lower alkoxy-lower alkyl acrylate and / or Hydroxy-lower alkoxy-lower alkyl methacrylate. 3. Printing plate according to claim 2, characterized in that the water-insoluble polymer from a polymer of hydroxyethyl acrylate and / or hydroxyethyl methacrylate and / or hydroxypropyl acrylate and / or hydroxypropyl methacrylate. 4. Printing plate according to claim 3, characterized in that the polymer is a straight chain Polymer is. 5. Printing plate according to claim 3, characterized in that the polymer is a mixed polymer of the acrylate or methacrylate with a minor amount up to 15% of a crosslinking agent. 6. Printing plate according to claim 1, characterized in that the water-insoluble hydrophilic Polymer layer contains hardeners, namely oxidizing hardeners and / or aminoplast resins and / or epoxy resins and / or acid anhydrides and / or polyamines. 7. Printing plate according to one of claims 2 to 6, characterized in that the water-insoluble hydrophilic polymer layer contains finely divided powdered inorganic materials. 8. Printing plate according to claim 6, characterized in that the oxidizing hardening agent Dichromate is. 9. Printing plate according to claim 7, characterized in that the finely divided powdered inorganic Material is powdered silica. 10. Printing plate according to claim 7, characterized in that the finely divided powdered inorganic Material is powdered aluminum oxide.