SU528026A3 - The method of making forms for offset printing - Google Patents

Description

I

The invention relates to the printing industry and can be used (but when comparing offset printing plates.

Offset printing plates are made with 5 seconds by copying onto a substrate coated with photosensitive solder, photo forms, developing a photosensitive layer and processing printing and whitespace elements ..10

The process of making offset forms is long and laborious, j

The aim of HacTosnnero inventions is to reduce the duration of the process and to prepare 4 forms

The goal is achieved by, hp, a hydrophilic layer insensitive to light is applied onto the substrate, and copying the printout of the photo-form is eliminated by electrically irradiating the printing elements of the form.

The method of making the forms consists in that layers of various types, for example, 25, are insensitive to light applied to the substrate, having a well-developed surface.

vinyl alcohol, polyvinylpyrrolidone, pure alkylene oxides, polyalkylenimines, also cellulose ethers, kV. carboxymethylcellulose vine or oxethylcellulose, pyacrylamide. polyacrylic acid, polymethacrylic acid 1, starch, wheat gluten, dextrin, casein, gelatin, gum arabic and tannin.

Suitable monomeric or low cure I insoluble substances are, for example, tms not water soluble krasvtegas, kkv redamin B, methylene residue, eosinyl triphenylmethane dye like crystal violet, and a film that does not make a film. Here, first of all: otosos monomeric and oligomeric carbon-t | waters, including the products of reduction and compression obtained from them, as well as their admixture and nodote esters, salts, etc., eg, arabitol, sorbitol, pentaerythritol, a., "tae retreat, tetramethylolcyclopentanol, tetra methylcyclohexane, anhydroennaheptitis, gluconic acid, galactonic acid, mucous acid, and also alkali or monium salts, glucose, galactose, fructose, mannose, arabinose, sucrose, sucrose, mannose, alorano acid, sucrose, fructose, mannose, sucrose, sucrose, fructose, mannose, sucrose, sucrose, fructose, mannose, sucrose, sucrose, fructose, mannose, sucrose, fructose, mannose, sucrose, manganese, sucrose, mannose monolaurate, sucrose, monopa succinic laminate, mono-12 hydroxy stearate sucrose, in addition, such wetting agents, like sapanine sodium salts of alkylated sulfoberish of taynov acids and alkyl aryl sulphonic acids, polyglycodiol, polyglycol kilo-feLol ester, polyoxy-methyl sorbitan fatty acid ester and many others. Water-insoluble hydrophilic layers, which can have both inorganic and organic composition, can also be used successfully. The approach of organic and water-insoluble hydrophilic substances are, for example, products of compounds of phenolic resins and polytelexides, hardening melamine formaldehyde resins, or aminocarbonates. formaldehyde condensation resins or sulfenated urea formaldehyde resins, in addition, cross-linking hydrophilic colloids, for example polyvinyl alcohol, which in this case can also keep cow hydrophilic inorganic pigments. In addition, water-insoluble hydrophilic inorganic pigment layers are suitable, which are embedded in the surface of the substrate, for example, in a synthetic film or paper covered with synthetic material, for example, pyrogenic silicic acid}. A particularly important and expedient group of hydrophilic water-insoluble layers in accordance with the invention consists of layers that are formed by reactions of metal surfaces, in particular aluminum surfaces, with monomeric or polymeric organic or inorganic acids or their salts, or certain complex acids or salts. Such layers in the flat printing technique are widely known and used for pretreatment of metal subframes when applying photosensitive layers. For example, alkali silicates, phophoric acids or their derivatives, titanium or zirconhexahalides, organic polyacids, monomeric carboxylic acids or their derivatives, phosphomolybdates, silicomolybdates, etc. It is advisable to use treatment solutions with a concentration of 3-16 wt.%. In addition, boehmite layers are suitable as hydrophilic layers, which are deposited on aluminum substrates, in this case after anodizing, by treating them with hot water or hot aqueous solutions. In general, according to the invention, the hydrophilic layers must meet the condition that, in the case of flat or offset printing, they are moistened only with the last effect of the ink on the basis of oil and the moisturizing solution. Layers having this property are broadly known as base or base surfaces for offset printing forms. In addition, this condition is answered, as mentioned above, also by layers of water-soluble film-forming organic substances. Hydrophilic layers must have the ability to change the surface tension compared to water and ink when exposed to electrons, i.e. they are wetted not with water, but only with ink on an oil or fat base, i.e. :; hydrophobic or ole of. Although there are no solid ideas about the nature of the change during electron irradiation, it can be assumed that this results in polymerization or the formation of cross-links during the decomposition or transformation of hydrophilic groups, in particular OH groups, into hydrophobic groups. Hydrophilic layers whose hydrophilic properties are not based on oil. Cross-linked hydrophilic groups, such as the surfaces of metals such as chromium or pure, anodized surfaces on aluminum, are not suitable for use in the proposed process both. The base layers for hydrophilic layers are conventional materials for flat printing, for example paper containing cellulose acetate, zinc, magnesium, aluminum, chromium, copper, brass, steel, multi-metal, plastic or plastics-metal films. Mainly used is mechanically, chemically, or under the action of electric current chuck or anodized aluminum. If water-soluble hydrophilic layers are used, it is necessary that the entire surface of the substrate be hydrophilic. Otherwise, it can be chosen whatever. When electrons are irradiated by hydrophilic layers, the electron charge density is 10 ± 1 O cm – 2. At an accelerating voltage of about 5 to 50 kV. Depending on the sensitivity of the bomb

The irradiated layers can be from OjOOS to 10 sec per 2 cm of the path with a current from 1 µA to 1OO µA. Since the layers are insensitive to light, even to UV light, irradiation can be carried out in daylight. For electron beam irradiation, it is advisable to use a programmed linear and / or raster control.

A particular advantage of the method according to the invention is that the plate irradiated according to the invention can be immediately inserted into the machine for offset printing, and then printing can begin. The appearance and peeling of image-free plate areas, which is known for using self-covering and most often pre-sensitized offset printing plates, are not observed.

This advantage is consistent with the desire to accelerate and rationalize offset printing.

The treatment of irradiated materials in an offset printing machine is carried out either by the dry method or in the presence of a dampening solution. When wetting hydrophilic non-reproducing areas with a dampening solution, either the material is not entrained (water insoluble layers) or a relatively small amount of material absorbs a moisturizing solution (water-soluble layers) that easily peels off and is easily removed with flushing water. In contrast This, when developing conventional photosensitive layers, is mainly precipitated by aggressive substances, the removal of which requires additional measures.

In the examples below, preferred embodiments of the method according to the invention are considered.

Example 1. An aluminum plate with a thickness of 0.3 mm is mechanically roughened with brushes and immersed in a 2 0% solution of trisodium sphatate at 70 ° C for 3 minutes, rinsed with water, with OO nitric acid at 7 ° C and then rinsed again with hot treated with water for 3 minutes with a 1p% solution of sodium silicate at 8-5 ° C, washed with water and dried.

Insensitive to light, which for many years retains its properties as a coated aluminum plate, is then subjected to radiation according to the image by medium-speed electrons with energies of about 10-15 keV in deep air.

cuome (about), the beam current is 2OO µA,

After irradiation, the printing plate without further processing is stored in an offset machine and is ready for printing, with the irradiated areas absorbing the oil printing ink. The draw resistance of the form is several thousand h impressions.

EXAMPLE 2 A light rolled aluminum coil is rough-edged, anodized, processed with a 59b solution of polyvinylpyrrolidone in water and dried.

The light insensitive material is cut into pieces and, as described in Example 1, is irradiated according to the image by medium speed electrons. After irradiation of AgJao Inieva, the foil is clamped in an offset machine, and the printing starts.

The same result is obtained if, instead of polyvinylpyrrolidone, copolymers or casein, or 2, a solution in the water of a wheat glue glue, or a 5% solution of tannin in water, are used to coat it.

Example 3 A mechanically punched aluminum plate is coated by immersion in a solution of polyvini-phosphonic acid heated to 5%, dried and irradiated with electrons in accordance with the image. The beam current is 200 µA. The treated areas become oleophilic and absorb oily colors when printed.

Example 4, the Chromo-aluminum plate acquires a coating in a 2.5% solution in water of polyvinyl alcohol and is irradiated with electrons at a current in a beam of 100 µA. Immediately after this, printing begins.

The same result is obtained if a 6% dextrin solution, an 18% gum arabic solution, a 5% starch solution, a 2.5% wheat gluten solution or a 0.1% solution are used for the coating instead of the polyvinyl alcohol. hydroxyethylcellulose solution.

Example 5. An iodized aluminum plate acquires a coating in a 59s solution of polyethylene glycol with an average molecular weight of 3900-4800 and is irradiated with electrons at a beam current of 200 µA. The irradiated plate is immediately used as an offset printing plate.

The same result is obtained if it is processed in a 2.5% solution of polyacrylic acid.

Claims (3)

Example Anodized aluminum plate to create a boehmite sco, the thickness of which is at least ten times the thickness of the oxide layer, is completely immersed in pure soda at 95 ° C and dried. After the image is irradiated with electrons with a current in the beam of 200 µA, the irradiated areas become not photographic and, when inserted into an offset machine, absorb ink. With the same success, instead of anodized plastin, an aluminum plate can be applied to the deposition of a boehmite layer, finished with nylon brushes in suspension, after which the treatment is carried out in the same manner4 as described above. Example Tubing suitable for use as a printing plate of pentacles on penta, hydrophilic colloid flax binder with fine inorganic pigment, is irradiated with electrons at a current in a beam of 25 µA, and then copied during printing, as described in Example 1, Example. A mechanically brushed aluminum plate is processed in a 2% aqueous solution of crystal violet dye and dried: it is irradiated with electrons at a beam current of 100 µA. Then the printing plate is clamped in an offset machine and wiped by a sponge. Thanks to this extremely. the easily water-soluble dye layer is removed from the non-irradiated regions, but the irradiated regions are hardened and become oleophilic. Rubbing VL61ZhN1Y sponge is not necessary, however, when entering without prior wiping for a long time, you can download. thread car residual dye. Get over 100,000 prints. “You could just as well use dyes instead of crystal violet: rhodamine B, methylene blue, and eosin in the same concentrations. Claims 1. Instructional method for offset printing by depositing a layer on the substrate, receiving images, printing images of the printing elements of the photoform and processing the substrate applied on the substrate, characterized in that under the layer as a layer that perceives images, the hydrophilic layer is insensitive to light, and the copying of the image of the photoform is carried out by means of an eIIT poiffioro of irradiation of the printing elements of the form, 2. The POP-1 method is different in that 4TOj, water-soluble film-forming organic compounds are used as the hydrophilic layer. 3. The method according to claim 1, wherein (b), a metal substrate is used as a substrate, which is treated with monomeric acids I1Sh-IX salts.