Screen printing methods and requirements for special products

First, Lottery silk screen

In the past 10 years, the need for masking inks has increased year by year. In the offset text, numbers, symbols and then use screen ink thick screen printing film, so that it is completely covered, and then made of cards is a lottery ticket. Lottery tickets come in many forms, such as sports lotteries, social welfare fund-raising lottery tickets and so on. This type of lottery ticket can be seen by using coins or nails to scrape off the masked ink, and the printed text, numbers, etc. can be seen below. In addition, by masking images, words and numbers can be combined into a variety of interesting entertainment, which is very popular.

1. Lottery ticket composition, because most of the lottery tickets are one-off, so paper printing, generally 150 ~ 200g / m 2 coated paper. First of all, with offset printing of text, numbers, images, etc., the printing surface of the offset printing is flat, which is advantageous for the final screen printing. The offset-printed printing surface must be coated with a good transparency, and its function is not only to make the masking ink strippable, but also to make the offset printing image stable. The final screen printing is then performed on the coating using masking ink, typically only partially masked thick film printing is performed on the letter and the digits.

2. Lottery performance requirements. 1 After the masking ink with stability is printed on the lottery ticket, it should be easier to peel off with nails or coins. The ink lottery ticket printed as a commodity is stable for at least one year of circulation. 2 After removing the masking ink, the exposed characters, numbers, etc. cannot be contaminated by the ink. 3 Masking ink should have sufficient shielding. (4) The ink film that covers the ink should have certain toughness, that is, the surface of the ink film must not be damaged by some external force during operations such as drying or cutting of the lottery ticket, and the same requirements must be met in the circulation of the product.

From the above points of view, 3 and 4 are almost determined by the performance of the masking ink, so it is very important to select the appropriate ink. The 1 and 2 are determined by the degree of adhesion of the coated paper and the masking ink. The faults that existed in previous experiments are mainly 1 and 2, so this is a key issue.

Second, the silk screen of electrical decoration advertising board

The electric advertisement board generally projects light from the inside of the advertising board to make the surface more beautiful. The main materials used are acrylic plates and glass plates. In addition to printing, the board is also decorated with cutout text and lines. The main processes of screen printing electrical decoration advertising board are surface printing, inside printing, full shading printing and so on.

The most commonly used electric advertisement boards printed inside are electric screens printed on the inside of an acrylic board, and finally printed in solid white, and the surface of the board can be formed into a glossy decorative pattern. If the light inside disappears, light from other directions will reflect on the surface and various colors will appear.

In the case of surface printing, milky white translucent plates are generally used. Since all-white printing is not required, uneven quality rarely occurs, but scratches are easily generated on the surface.

When shading, it can be printed in two ways. If the surface is intended to be shaded with full red, the same plate may be used for shading purposes before the full red color is printed, silver or gray is printed, and then full red is printed on top. When the electric decoration is performed, only the text or the pattern part is highlighted, which is very clear and beautiful, so it is often used for the printing of road signs or guide plates.

In the case of acrylic printing, the material itself is highly charged due to its electrically charged nature and it is easy to adhere to dust.

Since dust adheres to the electrical panel very clearly, in order to eliminate dust and prevent static electricity, alcohol is used to wipe the substrate once before printing. Because the light is emitted from the inside, the printed scratch marks are also very noticeable. For this reason, great attention is paid to the grinding of the squeegee, the printing pressure, the printing speed, etc., and uneven printing should be minimized. Due to the use of a good light-transmitting ink, after printing and electro-decoration, the tinge of a person's tone seems to have changed completely. When combined with other colors, it is possible to make products that differ from the customer's requirements if light transmission is not observed. In the case of four-color printing, if the color is adjusted without light transmission, a very light and blurred image may be formed.

Third, the metal advertising board silk screen

Metal advertising boards refer to guide plates and billboards whose materials are metal plates. Their predecessors were billboards and melamine billboards. Metal materials are mainly made of aluminum and stainless steel. The surface of stainless steel has the advantage of no rust. After screen printing, hardener can be applied to the surface for processing. Aluminum can use its plasticity, embossed by the pressure method, so that its surface has a concave and convex pattern, enhance three-dimensional and improve visual effects.

The earliest metal billboards were enamel billboards. They were made of galvanized iron plates and used enamels to prevent rust. They were mostly used for billboards, place name plates, etc. Although this brand is adaptable to the climate, the process is time consuming and coloring is not easy. With the development of spraying technology, melamine billboards began to appear, which improved the rust-proof performance. It can be colored by digging-cut screen printing. Since the billboard began using hard plastic as the main material, the melamine advertising board gave people a sense of being out of date. Iron plate billboards are old and obsolete. Due to their own weight, processing is affected and it is difficult to circulate products.

The main material of the metal advertising board has been transformed into aluminum sheet or thin zinc sheet. These materials are light weight, have good processability, and are easy to handle even if they are large in size. In order to increase the strength of the metal sheet, a part of it may be raised as a rib, and the amount of material used is approximately the same as that of the flat plate.

Fourth, stainless steel products silk screen

There are many methods of processing on stainless steel surfaces, which can be roughly divided into two types. One is to treat stainless steel with surface gloss, and to use art processing to form a pattern using luster contrast; the other is to assign color to the composition of patterns. Art processing. Typical examples of the use of the screen printing method include etching and spray painting.

Etching processing method is to screen the acid-proof protective film on the stainless steel surface by screen printing, and then etch it with ferrous chloride solution to form an artistic pattern. The spray color method sprays pigment particles after screen printing to form a pear-like surface and form an artistic pattern.

In recent years, in order to adapt to the diversification of the use of stainless steel and higher and higher artistic requirements, the “color art” processing method with color has been developed and has become the mainstream in this field. Among the methods for imparting the color of stainless steel include a method of performing firing after screen ink printing and a chemical coloring method.

The process of chemical coloring of stainless steel products is: stainless steel products → screen printing → oxidation coloring → alkali treatment → finished products.

The etching art process of stainless steel products is: stainless steel products → silk screen → etching → alkali treatment → oxidation coloring → finished products.

The process of spray painting of stainless steel products is: stainless steel products → silk screen → etching → alkali treatment → screen printing → oxidation coloring → alkali treatment → finished products.

The stainless steel chemical coloring method does not use pigments and dyes, but soaks the stainless steel in a warm concentrated chromium sulfate solution to perform chemical coloring, which is characterized by good resistance to food. The ink used in this processing method must have a very strong acid resistance, and UV curing inks having special properties suitable for the processing process are generally used.

Fifth, the silk screen of the light reflector

The light reflector is a kind of silk screen that is irradiated by the headlights or other lights of a car and the light is reflected by the irradiated object in the direction of the light source without being affected by the angle of irradiation or the weather. Reflective is a hollow glass particle with a diameter of about 40 μm, with a reflective layer at the other heart. Its flexible sheet-like support has an adhesive layer and a release layer on its surface. A reflection layer is generally provided on an acrylic resin plate, and a reflection layer is formed by adding a certain amount of hollow glass particles with a transparent resin and printing by a screen printing method. When printing, we must carefully select the mesh number, hole width (opening degree), and the type of hollow glass particles. The hollow glass particles are regularly arranged.

This type of printing is used for various signs, commercials, etc. so that it can be confirmed in dark places. In addition, printing for road signs, air navigation signs, lifesaving appliances, security helmets, etc. can also be considered.

Six, with silk screen printing transfer aluminum

Gorgeous and beautiful, bright aluminum color hot stamping through the hot stamping machine, on the substrate, its beautiful color has won wide appreciation. However, sometimes the bronzing machine will also encounter products that are not suitable for mechanical bronzing. However, the customers are stubbornly not using screen printing gold. In the dilemma, the unique screen printing plate transfer galvanized aluminum shows its superiority. Hot stamping machine is mainly based on the temperature and pressure of the electro-aluminum stamping, and the screen-printed electro-aluminum is dependent on the role of the adhesive. The reason why adhesives can transfer anodized aluminum is because the outermost layer of anodized aluminum consists of a glue layer.

In the electro-aluminum transfer printing operation, the printed text must first be made into a screen plate, and the graphic requirements on the plate are clear. Then use a silk screen plate to print a layer of adhesive on the substrate, and then put the aluminum foil on it, and then use cotton or sponge to lightly press in the graphic area, wait until dry, tear off the anodized aluminum (strongly sticky Dry, torn off faster, there is a clear and bright picture of anodized aluminum.

Adhesive formulation is the key to transfer. The formulation shall be formulated as appropriate according to the nature of the printed material, the nature of the anodized aluminum layer, and the suitability of the screen plate. The formulation's viscosity and concentration should be properly formulated. For example, in the case of transfer cloths and polyvinyl chloride, polystyrene plastic products and wood products, the adhesive formulation is:

Perchloroethylene resin 100g

Xylene 50ml

Cyclohexanone 350ml

Perchloroethylene resins can also be used instead of or in combination with polyvinyl chloride resins. PVC resin with low molecular weight. When transclamming plastic products, xylene can be replaced with acetone in the above adhesive formulation. When transferring plexiglass products, some chloroform may be added. When transferring metals, ceramics, and glass products, the adhesive formulation is: 100% epoxy resin. (Ortho) dibutyl benzoate 3% to 5%, ethylenediamine 12% to 15% (concentration too high can add thinner).

Seven, silk screen prints

In recent years, silk screen printing has been promoted and popularized in China, and many high-level works have appeared. The artistic level of screen printing is close to woodcut prints, but the production of screen printing is much simpler than the production of woodcut prints. In addition to the commonly used paper, silk screen printing substrates include cloth, plexiglass, wood, porcelain, and metal plates. This has broadened the road for the development of practical use of silk screen printing, such as the production of posters, decorative paintings, clothing, headscarves and the like in the form of screen printing. The printmaker can fully design and produce practical art and improve its artistic level. Wall hangings, screens, curtains, Sofa covers, cushions, etc. are areas in which screen printing prints can play a role. On the one hand, pure artistic prints are produced. On the one hand, it is of great significance to open up positions for prints in practical art and to play a role in beautifying people's lives.

Eight, lacquer silk screen