Fabric printing refers to the process of forming patterns on fabrics through printing. Printing methods include stencil printing, screen printing, rotary screen printing, transfer printing and multicolor spray printing. Among them, screen printing originated from stencil printing (including stencil printing and zinc printing), gradually moved from manual operation to semi-automation and full automation, and later developed from flat screen printing to rotary screen printing.
There are generally several printing methods for fabric printing:
1. Pigment direct printing Pigment direct printing is to directly print the prepared printing paste on the fabric, which is the simplest and most commonly used printing process. Pigment direct printing technology generally refers to printing on white or light-colored fabrics, which is convenient in color matching, simple in process, and can be dried after printing, and is suitable for textiles with various fibers. The direct printing process of coatings can be divided into Akramine F adhesive according to the adhesives commonly used at present. Three direct printing processes: acrylate glue, styrene-butadiene emulsion and chitin glue.
2. The main methods of screen printing are direct printing, discharge printing and resist printing. The direct printing method has been introduced before, and the discharge printing method, transfer printing method and infiltration printing method will be introduced respectively below. This paper mainly introduces the dye-proof printing method.
3. Knitted underwear printing Knitted underwear printing mainly adopts pigment direct printing technology, and the fabric can be printed by double drying or natural drying, which avoids the problems of easy deformation of knitted fabric and difficult wet treatment of agricultural sheets. The printing method is mainly flat screen screen printing, which is divided into two ways: manual scraping and machine operation. This printing method can adapt to various flower patterns in various forms and structures, and is suitable for small batch and multi-color production.
4. Discharge printing Discharge printing, also known as engraving printing, refers to the printing method of printing colored fabrics with discharge agents, destroying some dyed pigments, and thus printing various patterns and patterns. Discharge agent is a chemical that can make the dye base fade. Such as: sodium chloride, stannous chloride, etc. This method can be divided into two types: white pattern (white drawing) and color pattern (printing). The latter dyeing method makes the fabric pattern fine, but the process is complicated and the cost is high.
5. The silk screen burnt-out system uses two kinds of fiber blended fabrics with different acid resistance. After acid rotten flower paste printing and chemical treatment, the acid-resistant natural fibers rot, and the acid-resistant chemical fibers are exposed, forming crystal clear flower patterns. Its special style makes the burned products have a high-grade and gorgeous feeling. Burnt-out products are not only gorgeous in appearance and excellent in internal quality, but also have the properties of wear resistance, high strength, easy washing, quick drying and non-ironing, which are well received by domestic and foreign markets. The research and application of burnt-out technology is popular in textile printing and dyeing industry in recent years.
6. Wool printing At present, printed wool fabrics are mainly thin plain fabrics or tulle fabrics, which are mostly used to make women's shirts, dresses, quilts and skirts. Wool fabric printing includes not only direct printing, but also pull printing, dye-proof printing and transfer printing. Wool blended fabric printing also accounts for a certain proportion. At present, the relief finishing of wool fabrics is also quite popular, mainly used for sweaters.
7. Velvet printing diamond printing uses the characteristics of silk printing to print on velveteen, which can obtain a special flash effect and shine like a natural diamond in the sun.
8. There are many kinds of special printing of foam printed fabrics, and foam printing is one of them. Foam printing is characterized by strong three-dimensional sense, similar to hand embroidery, soft to the touch, wear-resistant, washable, good in fastness and elasticity, and can be widely used in tablecloths, curtains, tea towels, handkerchiefs, pillow towels, clothing, tourist souvenirs and so on. It is not only suitable for cotton, linen, silk and other natural fiber fabrics, but also suitable for rayon fabrics.
9. Flocking printing electrostatic flocking is a new technology emerging in the textile industry. It is a product that uses high-voltage electrostatic field to plant short fibers on grey cloth. Flocking products are widely used in rubber, plastic, artificial leather and decorative products, especially small quantities of tourism products, because of their simple technology, strong three-dimensional sense and low cost. Flocking patterns on shoes, hats, children's clothes, trademarks and clothing will make them different.
10. Transfer printing Transfer printing is a printing process that relies on the sublimation of dyes and the diffusion and affinity of dye vapor to fibers to complete the coloring effect. Transfer printing is a practical printing and dyeing production method in waterless processing. In addition to not using water, there is also a main feature that the paper has small deformation and can print fine multi-level patterns and photographic pictures. Transfer the pattern picture to the cloth truly. Its effect is sometimes better than the general anti-corrosion discharge.
In addition to the above ten common printing methods, there are some special printing methods, such as anode transfer printing, photoluminescence printing, fluorescent printing, gold and silver powder printing, pigment foam printing, color-changing printing, fragrance printing, diamond printing, pearl printing and so on.
Plastic screen printing
Screen printing of plastic parts is one of the secondary processing (or reprocessing) of plastic products. The so-called secondary processing is a decorative surface treatment of plastic products after injection molding, such as plastic electroplating, plastic spraying, plastic hot stamping, plastic screen printing and so on. The secondary processing of plastic products is mainly determined by the properties of plastic itself, such as single dyeability and poor light resistance. In order to make up for these shortcomings and improve the appearance decoration of plastic products, secondary processing is needed.
There are many kinds of plastic products, but as far as screen printing is concerned, flat screen printing is used for plates and flat bodies; Curved surface screen printing method is used for curved surfaces that can be unfolded into planes; Indirect screen printing is used for special-shaped products. The resin, additives and molding methods of plastic products are different, and their surface properties are very different, especially the problems of surface smoothness, polarity and static electricity, which have become the root cause of the failure of plastic screen printing.
1.PVC plastic PVC screen printing was put into industrial production in 193 1 year. PVC plastic has the advantages of bright color, not easy to break, acid resistance, alkali resistance and low price. However, when making PVC plastics, some auxiliary materials are often toxic, so PVC products are not suitable for holding food. There are many kinds of PVC films, and most of the colorful plastic sheets and artificial leather on the market are PVC products.
2. Screen printing of ABS plastic ABS resin plastic is an engineering plastic. In recent years, it has been widely used in TV sets, calculators and many fields of national economy. ABS plastic is a terpolymer of acrylonitrile, butadiene and styrene. Because ABS plastic is a ternary polymer with the same characteristics of three components, acrylic eye can make the polymer resistant to chemical corrosion and have a certain surface hardness; Butadiene can make polymers have rubber-like toughness; Styrene can make polymers easy to process and shape. ABS plastic has a variety of colors, the product has a shiny appearance, low water absorption, good impact strength and surface hardness in a certain temperature range, and good dimensional stability. Most ABS resins still have considerable impact strength and toughness at -40℃, and their products are used at -40 ~ 60℃. ABS plastic has high molecular weight, good physical properties, easy processing and molding, and good printability.
3. Screen printing of polyethylene and polypropylene plastics Polyethylene plastics: Polyethylene plastics are widely used and can be made into various finished products through extrusion, injection and other molding processes. The molecule of polyethylene is a long chain composed of methylene and contains a certain amount of side groups. The more and longer the side groups in the polymer chain, the lower the crystallinity of the polymer. That is to say, the higher the density of polyethylene, the more unfavorable it is for surface finishing. Polyethylene is opaque in many solvents, but it can be dissolved in toluene, amyl acetate and other solvents when the temperature exceeds 70℃. This property of polyethylene provides conditions for surface treatment. The adhesion of ink film on plastic surface can be improved by soaking plastic in heated solvent to expand its surface and destroy some crystals. The mixed solution of fuming sulfuric acid, concentrated nitric acid, chromic acid and sulfuric acid can slowly act on polyethylene at room temperature; Sulfuric acid and nitric acid can quickly destroy polyethylene at 90~ 100℃; Soaking polyethylene plastic in the mixed solution of potassium heavy lead acid, sulfuric acid and distilled water at 70~75℃ is beneficial to enhance the adhesion of ink film on the plastic surface.
Polypropylene (PP) plastics: Polypropylene is one of the important varieties of plastics developed over the years. Suitable for all molding methods. Can be made of various tubes, boxes, films, fibers, etc. Industrial polypropylene has a high degree of spatial regularity and crystallinity, and its equivalent index is in the range of 89~95%. At the same time, it contains a small amount of three-dimensional block macromolecular chains with amorphous atactic structure and low crystallinity. The melting point is in the range of 170~ 175℃, the glass transition temperature of isotactic polymer is-13 ~ 0℃, and that of syndiotactic polymer is 0℃. Concentrated nitric acid and fuming sulfuric acid have corrosive effect on polypropylene, which can be dissolved in aromatic hydrocarbons and chlorinated hydrocarbons at high temperature, but can only expand it at room temperature. Acids and esters also have a certain corrosive effect on it, and the solvent resistance increases with the increase of isotactic polymer content.
Generally speaking, polyethylene and polypropylene are nonpolar molecular structures with high crystallinity and low surface tension. There are no polar groups such as carbon, carboxyl and hydroxyl in the molecular structure. Compared with polyethylene, surface coating of polypropylene is easier.
4. Screen printing of plastic parts of electronic products, especially radio products such as radios, tape recorders and televisions. , the appearance requirements are very high. Art designers attach great importance to the appearance decoration of products, but at present, there are few techniques of appearance decoration in China, which limits the thinking of art designers and can only change the appearance of products through the size of products, the use of various lines and the limited color of plastics. After the development of plastic screen printing, it brings convenience to the decoration of electronic products, so in recent years, plastic screen printing of various electronic products in China has been widely used.
5. Screen printing of plastic signs In recent years, plastic signs and decorative parts used for screen printing of pictures and texts after plastic molding have developed rapidly. For example, screen printing on PVC hard board, polycarbonate, ABS, plexiglass and modified polystyrene has been widely used and achieved good decorative effect and economic benefits.
6. Screen printing of soft and hard plastic parts ① Screen printing of plastic hoses. There are several ways to print plastic hoses, and the main method is thermal transfer. Thermal transfer printing method is to use sublimation dye ink or other materials to print pictures and texts on transfer paper, then attach them to the substrate, and heat them from the back of transfer paper to sublimate the paper dyes and transfer the pictures and texts to the substrate. The surface-treated plastic hose passes between the hose and the heated iron plate through solar gas and transfer paper, and the heated iron plate pushes transfer paper to the hose, and the transfer printing is completed by heating. After the transfer, the hose enters the drying device, and the drying temperature is generally around 65℃. ② Soft plastic screen printing. Soft plastics are mostly used to make toys, such as inflatable cartoon toys. When making, it is generally to screen print the pattern on the film plastic first, and then cut and thermally synthesize it. The thickness of the materials used is generally 0.8 ~ 3.0 mm If screen printing of more than two colors is carried out, most plastics will expand when heated and contract when cooled, resulting in misregister of the second color and the first color. This kind of color matching error makes the goods lose their original value and cannot be put on the shelves as qualified products. Therefore, multi-color printing can only use a long printing machine that can fix soft plastics, and there is no other way. When printing on a long platform, the substrate should be fixed with adhesive. It is worth noting that toy printing must use non-toxic and harmless ink specified in relevant standards. ③ Screen printing of hard plastic products. There are two kinds of hard plastic products: cardboard and molded products. Tickets, signboards, dashboards and cosmetic containers are all made of hard plastic.
7. The surface material of the dashboard screen printing panel can be metal, various plastics and paint. Select appropriate ink, screen print some words and graphics on the panel, show some functions of instruments and equipment, and beautify the panel at the same time. Screen printing requires clear characters and graphics, good adhesion and wear resistance, and also requires soft and elegant colors to give people a sense of beauty. Here we mainly discuss how to improve the quality of the panel through screen printing process.
8. Color polyester logo Screen printing polyester logo is a new logo that has developed rapidly in China in recent years. Because of its bright colors, good decoration, convenient pasting, simple manufacturing method, low cost and other advantages, it has been widely used in high, medium and low-grade electronic products, household appliances, stationery and other fields. At present, many professional factories in China have produced this sign. However, because the production technology of these factories is designed according to the needs of large-scale label processing, those polyester label products with many varieties and few quantities can not adapt to it in processing technology and production cost. This paper introduces a process technology of printing color polyester signs by screen printing technology, which can be used as a reference for manufacturers engaged in the production of small batch and multi-variety color polyester signs.
Metal screen printing
Metal screen printing has a wide range, which can print all kinds of logo roots, panels, signs and metal molded products. Most of them are decorated by direct printing, and the skills of screen printing are not much different, except that metal products are durable products, which require higher surface decoration and are more durable. Therefore, before printing, more surface treatments should be carried out, such as surface coating, electroplating, anodizing or mechanical roughening (scribing and wire drawing). Make sure the surface is clean when printing, so be sure to wear gloves when working. If the treated surface has oil stains, fingerprints, dust and other stains, it must be washed off with solvents such as trichloroethylene, thinner and gasoline. In addition, according to the surface properties of metals, suitable printing inks should be selected, such as amino and epoxy thermosetting inks should be used on the coating surfaces of amino baking varnish and epoxy baking varnish; Solvent volatile ink or oxidation drying ink can be used on naturally dried coatings such as nitro varnish, but solvent or diluent must be used carefully to prevent damage to the paint surface, and a layer of varnish should be applied after printing to improve luster and protect the whole surface; The electroplated surface of metal can also be printed with thermosetting ink, but attention should be paid to the difference of thermal expansion coefficient between electroplated layer and metal to control the heating temperature and avoid cracking of the coating due to the large difference of thermal expansion coefficient. Anodizing aluminum plate will form an oxide layer with uniform gap (about 2~ 10μm thick) with large surface area, which can improve the adhesion of coating (ink). In addition, it also has the performance of absorbing dyes, and can be used to make dyeing marks by diffusion ink or dip dyeing.
1. Screen-printed corrosion signs are a kind of traditional signs, including sandblasting oxidation paint filled signs used as instrument panels, corrosion paint painted signs used for vehicle license plates, equipment numbers and various machine tool electrical nameplates, copper-plated front signs used for electromechanical products with harsh industrial environment, porcelain oxidation paint signs used for surface decoration of instruments and electronic instruments, and high-gloss signs. In the past, the pictures and texts on these signs were all displayed with liquid photosensitive glue (protein glue, bone glue, gelatin, polyvinyl alcohol glue, etc.). ) by photochemical method. Although this method has the advantage of small deformation of graphics and text, it has many defects, such as many manufacturing processes, low production efficiency, high labor intensity and high energy consumption. Using screen printing to display pictures and texts can improve the production efficiency several times and save a lot of auxiliary materials and energy. The following is a detailed introduction to the graphic screen printing technology of corroded signs for readers.
2. Screen-printed alumina dye sign. Alumina sign has a hard and smooth surface, and is wear-resistant and durable.
After the holes of alumina signs and panels are sealed by oxidation, there is an oxide film on the surface, which makes the surface hard and smooth. Screen printing with ordinary ink often has poor adhesion, so we should pay special attention to it. To solve this problem, we must first solve the ink loss and operation problems in screen printing. Using alumina screen printing ink is the key to solve the problems of ink film adhesion and firmness in alumina screen printing. This kind of ink is different from ordinary ink, it will be firmly attached to aluminum plate and has good light resistance, so it is an ideal ink for screen printing aluminum anodic oxidation logo.
3. Screen-printed convex-concave color aluminum sign The convex-concave sign is characterized by being painted on the concave surface, which has good wear resistance and strong three-dimensional effect, and is mostly used for mechanical nameplates and company plaques. The traditional manufacturing method is to color the corroded concave surface by hand (or inject paint with an injection needle), and then trim it by hand to remove the residual paint on the edge. This method is not only time-consuming and inefficient, but also requires the operator to have skilled skills. Moreover, the signs made are often illegible, distorted and unstable in quality. Therefore, it is limited to making some signs with small batch, few colors, low quality requirements and very simple patterns.
4. Screen printing sand blasting oxidation paint embedded aluminum sign Screen printing sand blasting oxidation paint embedded sign technology is a traditional sign production technology. This kind of products are silvery white in appearance, with high surface hardness and good wear resistance.
5. Screen-printed wooden self-alumina sign Shuibai alumina sign is a new type of matt sign that has recently appeared in China. This sign is milky white in appearance, smooth and flat in surface, and has no concave-convex feeling. It has the properties of resistance to damp and heat, salt fog and mold, and also has the characteristics of strong sun resistance, wear resistance and organic solvent resistance. Suitable for machine tools that need to be wiped frequently and the whole machine that works under bad conditions. What's more commendable is that screen printing of water-white alumina signs has few production processes, high work efficiency and basically no "three wastes". The consumption of manpower and energy (including water and electricity) does not exceed one third of that of traditional corrosion signs.
6. Printed aluminum oxide color sign The aluminum plane anodic oxidation sign is one of the sign varieties and is widely used. It has the characteristics of beauty, brightness, high hardness and good wear resistance. In the past, the technological processes were aluminum plate blanking, mechanical polishing, chemical polishing and oxidation. Indirect screen printing to protect lithopone thick paint and alkyd varnish for printing; Colour with dye paste. This process, whether it is screen printing or dyeing, has many shortcomings, such as more materials, complicated working procedures, low printing resistance, poor resolution and high cost. Under the existing technical conditions, it is possible to formulate a new process with simple process, good quality and high efficiency. The new process uses non-toxic diazo photosensitive adhesive to directly make screen printing plates. Practice has proved that it can meet the requirements of rapid plate making, high resolution, high printing resistance and less materials. Moreover, the processes of printing protective paint, dyeing and printing material rejection can be combined into one, that is, self-made water-based dyeing materials can be directly dyed and continuously registered without color tanks. Thereby greatly simplifying the whole working procedure and operating procedure, and providing a new method for flat oxidation dyeing signs.
7. With the continuous development of production technology and the improvement of people's material and spiritual living standards, people not only demand higher and higher functions of products, but also demand higher and higher modeling and assembly of products. Especially with the development of market economy at home and abroad and the continuous expansion of foreign trade, people have higher and higher requirements for product functions and external quality. In order to improve the market competitiveness of products, high-quality products with high-gloss three-dimensional relief logo have been widely used.
8. Screen printed electroplated plaques are products produced by many sign factories. The plaque is mainly made of metal, which requires solemnity, distinctiveness and strong decoration. Among traditional metal plaques, square plaques with brass floors, corroded characters and black paint are the most common. With the constant change of people's aesthetic standards and the gradual development of commodity economy, there are new and different requirements for the quality of plaques. The introduction of screen printing technology into the sign industry not only promotes the development of screen printing technology, but also provides technical means for the sign industry to develop new products. The new electroplating plaque made by screen printing is the product of the combination of signboard electroplating and screen printing technology. The basic method is to screen print pure text pattern on copper plate, cover the non-graphic part with ink layer, electroplate copper, nickel and chromium system on the silver part of the pattern, and then carry out mechanical forming and protection treatment.
9. Imitation metal etching screen printing imitation metal etching printed matter has metal etching effect visually. In order to achieve the above effect, the surface of the substrate should have mirror luster. On the substrate, the concave-convex ink coating is printed with transparent ink to form a rough surface like ground glass. The combination of rough surface and strong contrast makes the printing surface concave, while the mirror surface produces convex printing effect. The stronger the contrast, the better the imitation etching effect. Concave-convex effect is proportional to the thickness of ink film. Its ink has a high solid content, and the effect will be better if a low mesh printing plate is used. At first, gel ink with propylene emulsion (50% solid content) was used in this technology. After drying, it must be heat-treated at 180℃. Therefore, the substrate is limited to heat-resistant metals and glass, and hard plastics and paper cannot be used. Due to the use of gel ink with high viscosity such as propylene emulsion and the operating temperature, the stability of ink viscosity is extremely poor, and the product quality fluctuates greatly. Due to the use of ultraviolet drying ink in screen printing, printing technology and technology have great flexibility. The UV ink is 100% curing type, which can be hardened by UV irradiation for 3 ~ 5 seconds, during which the surface temperature is about 100℃. If water-cooled ultraviolet irradiator is used, the temperature can be reduced to about 60℃, so the types of substrates will also increase, and it can be printed on mirror aluminum foil paper, evaporated paper, evaporated vinyl chloride film, evaporated polyester film and other materials.
10. Method of screen printing conical dial: firstly, screen print the pictures and texts on transfer glue, then install the conical part on the self-made special fixture, and then roll on the transfer glue to transfer the pictures and texts to the conical part.
1 1. Porcelain-like anodic oxidation sign The surface of porcelain-like anodic oxidation sign has luster, soft luster, good wear resistance, high hardness, wear resistance, good thermal insulation and electrical insulation, good covering ability and ideal adsorption ability, which is a good decoration for instruments, especially high-end machines. However, chromium-containing gas escapes in the production process, and the operating equipment should be equipped with good exhaust ventilation equipment to avoid poisoning. The surface pretreatment method of porcelain-like oxidation signs is basically the same as that of screen-printed sandblasting oxidation paint-embedded signs, except that porcelain-like oxidation corrosion signs are generally oxidized directly without chemical polishing. The stamping process of porcelain-like oxidation corrosion signs, porcelain-like oxidation dyeing signs and porcelain-like oxidation printing signs is generally carried out before oxidation. The oxidation process of porcelain-like oxidation corrosion marks is the same as that of sandblasting oxidation paint embedding, and the oxidation dyeing process of porcelain-like marks is the same as that of screen-printed alumina color marks.
Ceramic screen printing
For a long time, the pattern decoration methods on ceramics have been blowing, hand painting, rubber printing and transfer printing with copper plates and offset printing decals. In recent years, with the application of screen printing in ceramic industry, the decorative patterns on ceramics are more stereoscopic, and the fired enamel is thick and bright, which looks like painted enamel. Its pattern is finer than the general blow-spray method, and the production efficiency is also improved a lot. Because screen printing has many advantages in the decoration of ceramics, its application scope is getting wider and wider.
Glass screen printing
Glass screen printing is a decorative printing on glass products by using screen printing plate and glass glaze. Glass glaze, also known as glass ink and glass printing material, is a paste-like printing material mixed and stirred by pigment and binder. The pigment consists of inorganic pigment and low melting point flux (lead glass powder); Adhesive is commonly known as printing oil in glass screen printing industry. Printed glass products should be fired in a kiln at 520~600℃, and the glaze printed on the glass surface can be consolidated on the glass to form colorful decorative patterns. If screen printing is combined with other processing methods, the effect will be better. For example, before or after printing, polishing, engraving and etching can be used to treat the glass surface, which can double the printing effect.
1. Etching screen printing of glass products For a long time, the etching decoration of glass products is to coat a layer of wax and other reinforcing materials on the glass surface as an anti-corrosion layer, then carve patterns on the coating with a needle and a knife to expose the glass surface, and then coat hydrofluoric acid on this part for corrosion. This technology has been applied by manufacturers until now, but its processing method is time-consuming, laborious and inefficient. Screen etching process makes the etching decoration of glass products simple, time-saving and labor-saving. There are two methods for etching screen printing of glass: hot printing and cold printing. Thermoplastic etching screen printing is an anticorrosive printing material made by adding a small amount of anticorrosive powder to adhesives made of paraffin, asphalt and stearic acid. Then, the printed materials are scraped to the glass surface according to the design pattern by hot printing screen printing to form an anticorrosive film. The portion of the resist film that exposes the glass is the pattern to be etched. Etching is carried out with chlorofluorinated acid. After etching, the corrosion-resistant layer printed on the glass should be washed off with boiling water. Glass screen printing etching can also be carried out by cold printing. Anti-corrosion printing materials can use special asphalt paint and anti-corrosion powder, or buy commercially available anti-corrosion ink. After printing is completed, hydrofluoric acid etching may be performed after the resist film is completely dried. Hot printing is suitable for etching two-way continuous and four-way continuous patterns, and cold printing is suitable for etching individual patterns.
2. Glass icing silk-screen icing, commonly known as orange peel, is actually a very fine glass particle with a low melting point. This tiny glass particle contains a lot of lead, including color and colorless, while the colors are red, yellow, blue, green and white. , you can also prepare the middle tone. Screen-printed ice flower decoration is elegant and generous, and is mostly used for architectural glass decoration and arts and crafts glass decoration, such as the decoration of high-grade glassware and lamps. Screen printing glass icing decoration is to screen print a colored or colorless glass flux layer (flux) on the glass surface, and then sprinkle icing glass particles on this glass flux layer. After sintering at 500~590℃, the flux layer on the glass surface is fused with the icing particle layer to produce the relief effect. For example, colored flux is screen printed on glass, while tiny ice flakes are transparent. If the glass melts at high temperature, the flux layer in borneol will fade, and a transparent relief pattern with colored bumps will be formed on the glass surface.
3. Glass screen printing frosting is a decorative method in which glass glaze powder with a certain size and area is attached to the finished glass and baked at a high temperature of 580~600℃, so that the glass glaze layer melts on the glass surface and presents a different color from the glass body. The adhesion of glass frit powder can be carried out by brush coating or roll coating. Through screen printing, you can get the empty pattern of frosted surface. The method is as follows: on the surface of glass products, a layer of pattern formed by flux blocking agent is screen printed. After the printed pattern is air-dried, it is frosted. Then, after high temperature baking, the frosted surface without pattern melts on the glass surface, while the frosted surface with pattern on silk screen cannot melt on the glass surface due to the action of flux blocking agent. After baking, transparent patterns of empty buildings will appear through the translucent sand surface, forming a special decorative effect. The flux blocking agent used for matte screen printing is composed of iron oxide, talcum powder and clay. Grinding with a ball mill with fineness of 350 mesh, and mixing with adhesive before screen printing.
4. Screen printing ion exchange coloring of glass. Colored glass can be obtained by exchanging silver with sodium ions in glass and then reducing it to metal colloid. On the transparent glass plate, only the part to be colored is printed with screen ink containing silver ions. After firing and cleaning, only the printed part changes from yellow to brown. Different firing conditions will change the hue and concentration. Because there is no reflection difference between the uncolored part and the colored part, there is no unnatural feeling at all, just like glass melting and coloring. The coloring of characters and marks on the glass, the anti-heat treatment of automobile rear window glass, and the brown color of the scale used in the comparative experiment are all obtained in this way. The silk-screen printing ink (printing material) of this decoration process is mostly composed of silver carbonate, copper sulfate (calcined powder), iron oxide, talcum powder and so on. Using a small amount of zinc powder as catalyst.
5. When designing the temperature program of microwave oven, the switch combined with microcomputer is adopted in the screen printing contact control panel. This switch is different from the usual mechanical switch, it is printed on the glass plate. It has no moving parts and no convex or concave. It is very smooth, easy to decontaminate and can be opened and closed by touch. The surface of this control panel is covered with a conductive film, and the surrounding is decorated and displayed with screen-printed ceramic ink. Its advantages are mechanical wear resistance, chemical corrosion resistance and easy decontamination. In addition, in order to color the glass, organic paint can be printed on the back. Because the back can't be directly contacted, it has strong durability and large ink selection.
6. Matte screen printing on the glass surface Matte ink (made in Belgium) is printed on soda-lime glass with a screen printing plate, and it is cleaned after a few minutes, and the effect is like brown glass. Usually, fluoric acid is used to etch glass, which is dangerous. This kind of ink contains no strong acid, and its operation is simple, and its extinction effect is similar to that of etching.
7. Screen printing of electric defogging devices In order to prevent water vapor from condensing on the rear window glass of automobiles, more and more electric defogging devices are printed. This screen printing method is to draw silver paste into lines on smooth glass and burn the glass while bending. When the rear window is foggy, the circuit will be heated by current, which will increase the surface temperature of the glass and eliminate water vapor. When this electric defogging device is powered on, some cars automatically power on and off without manual switch. The sensor of this automatic device is a serrated electrode printed on thin glass by screen printing, and then covered with a layer of humidity sensor, and the power supply is automatically controlled by humidity ratio.
8. Screen printing of liquid crystal display elements Liquid crystal digital display elements are arranged at an interval of about 10μn .. The peripheries of two thin glass plates are sealed, liquid crystal is injected, and the injection port is sealed. On the surfaces of these two pieces of glass, transparent conductive wires in the shape of "8" are screen printed. This "8" consists of seven parts, which can partially increase the voltage to display the number of (0~5). The process of making this figure-eight pattern is as follows: first, on the field glass with the whole conductive stranded wire, only the figure-eight part is screen printed with idle acid-resistant ink, and then the unprinted conductive stranded wire is removed by acid etching. Screen printing has become an indispensable technical means in the manufacture and production of electronic products. Such as product shell decoration, printed circuits, thick film integrated circuits, solar cells, electricity; Screen printing technology has been used to produce capacitors, piezoelectric elements, photosensitive elements, thermal elements, liquid crystal display elements and so on.