Photopolymer printing forms. Method for processing a photopolymer printing form Processing photopolymer forms

Polymer forms

This means that some polymer reacts to light. There are 2 types of polymers: either they are “cross-linked”, i.e. polymerize or harden under the influence of light, or, on the contrary, they become soluble. This is what the entire printing plate production technology is built on.

The scope of application of photopolymer printing forms is any printed product.

Advantages of use:

– good registration (since the accuracy of paint application, on which the quality of color image prints depends)

– it is possible to reproduce images with lineature up to 120 l/cm (high lineature)

– simple production of printing plates

– high circulation resistance

– multiple use

Flaws:

– unstable to some components of printing inks (printing inks, if not meeting the requirements, can corrode the printing plate)

General requirements to flexographic printing forms

1) Uniformity of the printing surface with good ink perception and ink output

2) Small deviations in plate thickness (plate thickness uniformity)

3) High circulation resistance

Classification of Photopolymer Printing Forms(total 2 varieties)

1. Solid polymer, so-called. TPFM (solid polymer photographic materials)

2. Liquid polymer forms - LFPM

Solid polymer forms are single-layer and multi-layer

Hardness, surface, information properties.

Structure of solid polymer printing forms,

Single layer consists of 4 layers:

- protective film

– anti-adhesive layer (i.e. comes off together with the protective film, does not allow it to stick strongly to?)

– photopolymer layer

– backing film

Multilayer:

- protective film

– anti-adhesive layer

– photopolymer layer

– stabilizer film

– backing layer

– anti-adhesive layer

- protective film

The photopolymer interacts strongly with oxygen (loses its photosensitive properties, hardens in air, etc.), so there is a film on both sides.

A substrate is needed so that during production a thin layer of photopolymer is poured onto it, which hardens. Then the whole thing is cut into the pieces we need.

Single layer plate. This photopolymer hardens under the influence of UV (polymerization occurs). If we put a photo form on top and put the whole thing under ultraviolet light, then under the transparent areas of the photo form, roughly speaking, the molecular bonds will be destroyed, which are then very easily removed (by washing, blowing with air, mechanical brushes - it doesn’t matter). We still have the printing elements, but the space element has such properties that it can be easily removed.

The composition of the photopolymerizing layer includes monomers (i.e. what is a “polymer” - roughly - a very long molecule), photoinitiators (a substance that is the source of a further chain reaction, i.e. a substance, when it receives a dose of UV, starts the reaction - it changes itself and causes the molecules around it to also change), elastomeric binder, stabilizers and additives.

The polymer itself is not photosensitive (it doesn’t care what kind of light is shined on it), but the photoinitiator cares, and when ultraviolet light is shined on the photoinitiator, it itself changes and causes nearby polymer molecules to also change (the domino principle - it fell and knocked down others) .

Production process: the roll with the backing film is unwound, the polymer is poured onto it in an even layer, with a protective film on top to prevent exposure to oxygen. Then it is cut into the desired format.

1.Create a print layout:

Draw the print layout with the necessary data on a computer in any program and invert it into a negative (black and white) image.
We offer the CoralDraw program to create a print layout and to help “beginners” a disk - “Seals and Stamps. Security Elements” (RUB 3,000), with a large selection of layouts, fonts, templates and images.

2.Print the layout:

Print on laser printer with a resolution of at least 600 dpi on matte Kimoto film or transparent LOMOND film (pay attention to the quality of the negative).

3.Treat the negative with toner:

Treat the negative with toner, after which the dark background should darken. Use original cartridges and toner.

4. Place the negative on the glass:

After wetting the back side of the film, place the negative face up on glass that has been previously moistened with water (for better adhesion).

5. Cover the negative with protective film (optional):

Cover the top of the negative with protective film (optional). Using smoothing movements, remove any remaining water from under the film (to prevent the formation of air bubbles and improve contact).

6. Cover with border tape:

Cover the perimeter with curb tape, limiting the space for the polymer, leaving gaps in the corners.

7. Fill the negative with photopolymer:

Evenly, without interrupting the stream, fill the negative with photopolymer and remove the resulting bubbles by blowing with air from a rubber bulb or a sharp object (paper clip, toothpick, needle).

8. Cover with film-substrate:

Cover with a substrate film (the rough side on the polymer! The glossy side on the outside!), starting from the middle, as shown in the figure. We touch the center of the polymer with the film without pressing and simply release the edges - they will straighten out on their own and lie on the polymer.

9.Cover with a second glass:

Cover the resulting composition with a second glass and clamp it around the edges with clips (stationery clips can be purchased separately at any stationery store).

10.Place in the exposure chamber:

Place the glass cassette face up in the exposure chamber.

11.Start the timer:

Set the exposure time on a digital timer, which largely depends on the properties of the photopolymer. For polymer grades VX55, ROEHM on the transparent film side (at first) it is approximately 20 -30 seconds. Start the timer by pressing the CD button. At the same time, the timer will begin counting down, and a blue glow from the lamps will appear inside.

12. Set the exposure time on the timer:

After the timer counts down and the lamps go out, turn the cassette over with the matte film (negative) facing up and start the exposure process again (CHANGING THE TIME). For polymer grades VX55, ROEHM, the exposure time on the reverse side (second time) is 1 minute. A more accurate time is determined experimentally by changing the time of both exposures. See the brochure “Technological Regulations”. When finished, remove the cassette from the camera.

13.Separating the glass, separate the negative:

Carefully separating the glass, separate only the negative and the protective thin film from the photopolymer. Do not separate the substrate (transparent) from the print. After removing the hardened polymer from the glass, some of it remains liquid, so it then needs to be washed.
ATTENTION!
Very often, novice manufacturers violate manufacturing technology, namely, the print must contain a rigid printing base - a substrate! This film has two sides, one of which the rough side is applied to the photopolymer, and the smooth side is used later for gluing to tape (on equipment, on the body). It does not need to be separated from the photopolymer after the manufacturing process!
For example: if you give a comparison, imagine a person who does not have a bone skeleton, and a seal without a substrate.

14.Rinse the cliché:

To clean from unhardened polymer, rinse the cliche well with a brush and a washing and degreaser such as Fairy, Cinderella under warm (not hot) running water.

15. Place the cliche in water:

Place the cliche in a bath of water in the exposure chamber for 7-10 minutes to harden.

16.Cut off excess polymer:

Cut out the cliche, cut off all excess polymer. Cut carefully without touching the edges, otherwise the print will be rejected. This stage must be approached very carefully so that you do not have to repeat everything from the beginning.

17.Glue the cliche onto the equipment:

Paste the finished cliche onto the equipment.

In our store, visit the section where you can purchase consumables.

3. Production of letterpress printing forms based on photopolymer compositions

A significant factor in the development of flexographic printing was the introduction of photopolymer printing forms. Their use began in the 60s, when DuPont introduced the first Dycryl letterpress plates to the market. However, in flexo they could be used to make original clichés, from which matrices were made, and then rubber molds were made by pressing and vulcanization. A lot has changed since then.

There are two types of plate material for making flexographic plates: rubber and polymer. Initially, the forms were made on the basis of rubber material, and their quality was low, which, in turn, made the quality of flexographic prints in general low. In the 70s of our century, a photopolymerizing (photopolymer) plate was first introduced as a plate material for the flexographic printing method. The plate made it possible to reproduce high-lineature images up to 60 lines/cm and higher, as well as lines with a thickness of 0.1 mm; points with a diameter of 0.25 mm; text both positive and negative from 5 pixels and raster 3-, 5- and 95 - percentage points; thereby allowing flexography to compete with “classical” methods, especially in the field of packaging printing. And, naturally, photopolymer plates have taken a leading position as a flexographic plate material, especially in Europe and in our country.

Rubber (elastomer) printing forms can be produced by pressing and engraving. It should be noted that the molding process itself based on elastomers is labor-intensive and not economical. The maximum reproducible lineature is about 34 lines/cm, i.e. The reproduction capabilities of these plates are low and do not meet modern packaging requirements. Photopolymer forms make it possible to reproduce both complex colors and transitions, various tonalities, and raster images with a lineature of up to 60 lines/cm with a fairly small stretching (increasing tonal gradations). Currently, as a rule, photopolymer forms are produced in two ways: analogue - by exposing UV radiation through a negative and removing uncured polymer from the gaps using special wash solutions based on organic alcohols and hydrocarbons (for example, using a wash solution from BASF Nylosolv II ) and through the so-called digital method, i.e. laser exposure of a special black layer applied on top of the photopolymer layer, and subsequent washing out of the unexposed areas. It is worth noting that in Lately in this area, new developments from BASF have appeared that make it possible to remove the polymer in the case of analog plates using ordinary water; or directly remove the polymer from the gaps using laser engraving in the case of a digital method of making molds.

The basis of a photopolymer plate of any type (both analog and digital) is a photopolymer, or so-called relief layer, due to which the formation of raised printing and deep space elements, i.e., relief, occurs. The basis of the photopolymer layer is a photopolymerizing composition (FPC). The main components of FPC, which have a significant impact on the printing technical characteristics and quality of photopolymer printing forms, are the following substances.

1) Monomer - a compound of relatively low molecular weight and low viscosity, containing double bonds and, therefore, capable of polymerization. The monomer is a solvent or diluent for the remaining components of the composition. By changing the monomer content, the viscosity of the system is usually adjusted.

2) Oligomer - an unsaturated compound with a molecular weight greater than the monomer, capable of polymerization and copolymerization with a monomer. These are viscous liquids or solids. The condition for their compatibility with the monomer is solubility in the latter. It is believed that the properties of coatings obtained during curing (for example, photopolymer printing forms) are determined mainly by the nature of the oligomer.

The most common oligomers and monomers are oligoether and oligourethane acrylates, as well as various unsaturated polyesters.

3) Photoinitiator. Polymerization of vinyl monomers under the influence of UV radiation can, in principle, occur without the participation of any other compounds. This process is simply called polymerization and proceeds rather slowly. To speed up the reaction, small amounts of substances (from fractions of a percent to percent) are introduced into the composition, capable of generating free radicals and/or ions under the influence of light that initiate a polymerization chain reaction. This type of polymerization is called photoinitiated polymerization. Despite the insignificant content of the photoinitiator in the composition, it plays an extremely important role, determining both many characteristics of the curing process (photopolymerization rate, exposure width) and the properties of the resulting coatings. Derivatives of benzophenone, anthraquinone, thioxanthone, asylphosphine oxides, peroxy derivatives, etc. are used as photoinitiators.

The nyloflex ACE plate is designed for high-quality raster flexographic printing in areas such as:

Flexible packaging made of film and paper;

Beverage packaging;

Labels;

Preliminary sealing of the corrugated cardboard surface.

It has the highest hardness among all nyloflex plates - 62° Shore A (Shore A scale). Main advantages:

Change in color of the plate during exposure - the difference between the exposed/unexposed areas of the plate is immediately visible;

The wide exposure width ensures good fixation of the halftone dots and clean recesses on the reverses; masking is not required;

Short processing time (exposure, washout, finishing) saves work time;

A wide range of tonal gradations on the printing plate allows you to simultaneously print raster and line elements;

Good contrast of printed elements facilitates installation;

High-quality paint transfer (especially when using water paints) allows you to reproduce the raster and the solid evenly, and reducing the required volume of transferred ink makes possible printing smooth raster transitions;

High hardness with good stability, transmission of high-lineature raster transitions using the technology of “thin printing plates” in combination with compression substrates;

Wear resistance, high circulation-resistance;

Ozone resistance prevents cracking.

The plate shows excellent paint transfer, especially when using water-based paints. In addition, it is well suited for printing on rough materials.

Nyloflex ACE can be supplied in the following thicknesses:

ACE 114-1.14 mm ACE 254-2.54 mm

ACE 170-1.70 mm ACE 284-2.84 mm

The plate has a low hardness (33° Shore A), which ensures good contact with the rough and uneven surface of corrugated cardboard and minimizes the washboard effect. One of the main advantages of FAC-X is its excellent ink transfer, especially for water-based inks used when printing on corrugated cardboard. Uniform printing of dies without high printing pressure helps to reduce the increase in gradations (dot gain) during raster printing and increase the contrast of the image as a whole. In addition, the plate has a number of other distinctive features:

The purple tint of the polymer and the high transparency of the substrate make it easy to control images and mount forms using adhesive tapes on the plate cylinder; - high bending strength of the plate prevents peeling of the polyester backing and protective film;

The form is easy to clean both before and after printing.

The nyloflex FAC-X plate is single-layer. It consists of a photosensitive photopolymer layer applied to a polyester substrate for dimensional stability.

Nyloflex FAC-X is available in thicknesses of 2.84mm, 3.18mm, 3.94mm, 4.32mm, 4.70mm, 5.00mm, 5.50mm, 6.00mm, 6.35mm .

The depth of the relief of nyloflex FAC-X plates is set by preliminary exposure of the back side of the plate by 1 mm for plates with thicknesses of 2.84 mm and 3.18 mm and in the range from 2 to 3.5 mm (depending on each specific case) for plates with thicknesses from 3.94 mm to 6.35 mm.

With nyloflex FAC-X plates you can obtain a screen lineature of up to 48 lines/cm and a gradation interval of 2-95% (for plates with thicknesses of 2.84 mm and 3.18 mm) and a screen lineature of up to 40 lines/cm and a gradation interval of 3-90% (for plates with thickness from 3.94 mm to 6.35 mm). The choice of plate thickness is guided both by the type of printing machine and the specifics of the printed material and the reproduced image.

The digiflex II photopolymer plate has been developed from the first generation of digiflex plates and combines all the advantages of digital information transfer with even simpler and easier processing. Advantages of the digiflex Ii plate:

1) absence of photographic film, due to which direct data transfer to the printing form is possible, protecting nature and saving time. After removing the protective film, a black layer becomes visible on the surface of the plate, sensitive to infrared laser radiation. Image and text information can be written directly onto this layer using a laser. In places affected by the laser beam, the black layer is destroyed. After this, the printing form is exposed to UV rays over the entire area, washed, dried, and final illumination occurs.

2) optimal transfer of gradations, allowing you to recreate the slightest shades of the image and ensuring high quality printing;

3) low installation costs;

4) highest print quality. The basis of laser-exposed photopolymer printing forms are nyloflex FAN printing forms for highly artistic raster flexographic printing, which are coated with a black layer. Laser and subsequent conventional exposures are selected in such a way that significantly lower gradation increments are achieved. The print results are exclusively High Quality.

5) reduced load on environment. No film processing not used chemical compositions for photo processing, closed exposure and washing units with closed regeneration devices lead to a reduction in harmful effects on nature.

The scope of application of plates for digital information transmission is wide. These are paper and film bags, corrugated cardboard, films for vending machines, flexible packaging, aluminium foil, film bags, labels, envelopes, napkins, beverage packaging, cardboard products.

Nyloflex Sprint - new for Russian market plate from the nyloflex series. Currently being tested at a number of production printing enterprises in Russia. This is a special water-washable plate for printing with UV inks. Washing with ordinary water makes sense not only from the standpoint of protecting nature, but also significantly reduces the processing time compared to technology using an organic washing solution. The nyloflex sprint plate requires only 35-40 minutes for the entire deprivation process printed form. Due to the fact that for washing you only need pure water, nyloflex sprint also allows you to save on additional operations, because used water can be poured directly into the sewer without filtration or additional purification. And for those already working with water-wash plates and nyloprint processors to make letterpress plates, you don't even need to purchase additional equipment.

Use: in printing for the production and processing of photopolymer letterpress clichés. The essence of the invention: the finished photopolymer printing plate is irradiated with a beam of electrons and/or y-quanta in the energy range of 0.5-10 MeV with a particle flux density of 10tT-1012 particles/cm2 s for 1-30 minutes. 1 table

RESG!U1 LIC (19) s

K (2 (2 (4 (7 ve (7 (7 ve (5

F m s k r a sh f m to st g top vk u b u i e st u e

SHOCKING 1st IlAI F. I I I IOE House of the USSR

SPATENT USSR)) 5018354/12

) 08/30/93. Bull. No. 32

) A.P. Ignatiev, V.A. Senyukov and M.E. Berg

) Limited Liability Partnership "Firm Triam"

6234. class. B 41 N 1/00, 1983.

The invention relates to the technology of making and processing photopolymer atomic forms based on solid photopoerizable material, in particular topolymer letterpress cliches, and can be used in the printing industry.

The purpose of the invention is to expand the temperature range of use and improve the performance characteristics of the topolymer printing form by changing the physical and mechanical properties of the foam polymer. The required technical result is achieved by the fact that in the method of processing the foam polymer printing form, which involves irradiating it, according to isotene, the finished printing form is irradiated with an electron beam and /or y-quanta in a burst of energy of 0.5 - 10 MeV with a particle flux density of 10 -10 particles / (cm, s) 1 - 30 min.

The essence of the proposed honeycomb method is that the finished polymer form is exposed to an ionizing agent (sI>c B 41 N 1/00, B 41 C 1/10, G 03 F 7/26 (54) METHOD FOR PROCESSING PHOTOPOLYMER PRINTED FORM (57) Use : in printing for the production and processing of photopolymer letterpress clichés. The essence of the invention: the finished photopolymer printing plate is irradiated with a beam of electrons and/or y-quanta in the energy range of 0.5 - 10 MzV with a particle flux density of 10 -10 particles/cm.s. in TT 12 2 for 1 - 30 min 1 table of radiation, while the products of ionization and excitation of molecules of polymer compounds are distributed throughout the volume of irradiated printing forms in accordance with the distribution of absorbed doses. Thus, selecting the appropriate distribution and dose rate in the irradiated sample , it is possible to obtain new desirable properties of a photopolymer compound that do not arise without a radiation-chemical™ process. polymer form a beam of electrons and/or y-quanta allows you to expand the temperature range of use of photopolymer cliches to 200 C, increase the elastic limit and Young's modulus, increase the hygroscopicity of photopolymer printing forms, which ultimately improves. operational characteristics of photopolymer letterpress printing clichés and allows their use at elevated temperatures. The proposed method of processing a photopolymer printing plate is implemented when testing on samples from

1838158 known photopolymers of the "Cellofot" and "Flexofot" types as follows.

Example 1. A sample of a printing form made from a photopolymer of the "Cellophoto" type is irradiated with an electron beam with an energy of 8 MeV for 15 minutes with an electron beam current equal to

19 μA, Measurement of physical and mechanical parameters is carried out at a temperature of 20 C, Example 2. A sample of a printing form of a photopolymer of the "Flexofot" type is irradiated with an electron beam with an energy of 10 MeV with an electron beam current equal to 10 μA for 25 minutes. Measurement of physical and mechanical parameters is carried out at a temperature of 20 C, 15

Example 3. Similar to example 1.

Measurement of physical and mechanical parameters is carried out at a temperature of 140 C.

The modes of the method were selected based on the following considerations: at an electron energy of 20 electrons below 0.5 MeV (Ee 10 MeV, photonuclear reactions, the equipment is activated - 25, a radiation hazard arises, At the electron flux density

P 10 electron12 nova/cm.s a significant amount of absorbed energy leads to radiation heating and destruction of the photopolymer cliche.

When studying changes in the physical and mechanical properties of photopolymers, the following characteristics were determined: elastic modulus (Young's modulus), elastic limit, hygroscopicity.

Data from studies of the physical and mechanical properties of photopolymers are given in table 45.

From the Bèäno table, for a photopolymer of the “Cellofot” type, after irradiation, compared to the original sample, the elastic modulus increases by 30-40, and the elastic limit by 4 times. For photopolymer type

"Flexofot" after irradiation, in comparison with the original sample, the Young's modulus increases by 4.8 times, the elastic limit by 44 times, and the hygroscopicity by 50, which significantly affects the quality of the prints. Photopolymer of the "Flexofot" type becomes hydrophilic after irradiation, which makes it possible to use various stamp inks up to ordinary ink without reducing the quality of prints, Testing a sample of photopolymer type

"Cellofot" at elevated temperatures (up to 150 C) showed that Young's modulus increases by 1.8 times, the elastic limit by 3.6 times and, if at elevated temperatures the circulation resistance of non-irradiated cellophoto is 0, then after irradiation the number of prints is 10,000 copies. Increasing the thermal stability of a photopolymer of the "Cellophot" type under the influence of ionizing radiation will make it possible to abandon the use of metal when creating printing forms operating at elevated temperatures. Printing forms made from a photopolymer of the "Cellophot" type and irradiated with a beam of electrons and/or y-quanta, according to the proposed method, operable at temperatures of the order

200 C and can be used in circulation more than 10,000 times without destroying the printing plate.

Modern photopolymer forms (FPF). General scheme for manufacturing FPF

The use of photopolymer printing plates began in the 60s. A significant factor in the development of flexographic printing was the introduction of photopolymer printing forms. Their use began in the 60s, when DuPont introduced the first Dycryl letterpress plates to the market. However, in flexo they could be used to make original clichés, from which matrices were made, and then rubber molds were made by pressing and vulcanization. A lot has changed since then.

Today, the following manufacturers of photopolymer plates and compositions are best known on the global flexographic printing market: BASF, DUPONT, Oy Pasanen & Co, etc. Thanks to the use of highly elastic forms, this method makes it possible to print on various materials while creating minimal pressure in the print contact area (we are talking about pressure created by the printing cylinder). These include paper, cardboard, corrugated cardboard, various synthetic films (polypropylene, polyethylene, cellophane, polyethylene terephthalate lavsan, etc.), metallized foil, combined materials (self-adhesive paper and film). The flexographic method is used primarily in the packaging industry, and is also used in the manufacture of publishing products. For example, in the USA and Italy, about 40% of the total number of all newspapers are printed using flexographic printing on special flexographic newspaper units. There are two types of plate material for making flexographic plates: rubber and polymer. Initially, the forms were made on the basis of rubber material, and their quality was low, which, in turn, made the quality of flexographic prints in general low. In the 70s of our century, a photopolymerizing (photopolymer) plate was first introduced as a plate material for the flexographic printing method. And, naturally, photopolymer plates have taken a leading position as a flexographic plate material, especially in Europe and in our country.

Manufacturing of FPF.

When producing photopolymer forms for flexographic printing, the following basic operations are performed:

1) preliminary exposure of the reverse side of the photopolymerizable flexographic plate (analog) in an exposure installation;
2) the main exposure of the installation of the photoform (negative) and the photopolymerized plate in the exposure installation;
3) processing of a photopolymer (flexographic) copy in a solvent (washing out) or thermal (dry heat treatment) processor;
4) drying of the photopolymer form (solvent-washout) in a drying device;
5) additional exposure of the photopolymer form in the exposure installation;
6) additional processing (finishing) of the photopolymer mold to eliminate the stickiness of its surface.