1. Screen printing is a kind of printing with a wide range of applications. According to the different printing materials, it can be divided into: fabric printing, plastic printing, metal printing, ceramic printing, glass printing, electronic product printing, lottery screen printing, electronic decoration advertising board screen printing, Metal advertising board screen printing, stainless steel product screen printing, light reflector screen printing, screen transfer anodized aluminum, screen printing and lacquer screen printing, etc. Fabric printing

Textile printing refers to the process of forming patterns on fabrics by printing. Printing methods include: pattern printing, screen printing, drum screen printing, transfer printing and multi-color shower printing. Screen printing is derived from pattern printing (including pattern paper and zinc plates). From manual operation, it gradually moved towards semi-automation, complete automation, and later developed from the flat mesh type to the rotary mesh type.

There are generally several printing methods for fabric printing:

1. Direct printing with paint Direct printing with paint is to print the prepared printing paste directly on the fabric. This is the simplest and most commonly used process in the printing process. The paint direct printing process generally refers to printing on white or light-colored fabrics. It is easy to match colors and has a simple process. It can be baked after printing and is suitable for textiles of various fibers. The paint direct printing process can be divided into Acramin F-type adhesives according to the adhesives commonly used at present. There are three direct printing processes: acrylic adhesive, styrene-butadiene emulsion and chitin adhesive.

2. Silk printing The main methods of silk printing include direct printing, discharge printing and resist printing. The direct printing method has been introduced before. The discharge printing method, transfer printing method, penetration printing method, etc. will be introduced separately in the relevant sections below. Here we mainly introduce the resist printing method.

3． Knitted underwear printing Knitted underwear printing mainly uses the paint direct printing process. After printing, the fabric can be doubled or dried naturally, which avoids problems such as easy deformation of knitted fabrics during wet processing and difficulty in wet processing of agricultural films. The printing method is mainly flat screen screen printing, which is divided into two methods: manual scraping printing and machine operation. This printing method can adapt to various patterns and organizational structures, and is suitable for the production needs of small batches and multiple colors.

4. Discharge printing Discharge printing, also known as engraving, refers to a printing method that uses a discharge agent to print on colored fabrics to destroy the dyed pigments, thereby obtaining various patterns and patterns. Dye discharge agent is a chemical that can make dye base lose color. Such as: Diaobaijue, stannous chloride, etc. This method can be divided into two types: the pattern is white (discharge printing) and the pattern is colored (discharge printing). The latter dyeing method makes the fabric pattern fine, but the process is complicated and the cost is high.

5. Silk screen burnout system uses two types of fiber blended fabrics with different acid resistance. After printing with acid burnout paste and chemical processing, the natural fiber part that is not acid-resistant is rotted away, exposing the acid-resistant chemical fiber part, forming a crystal-like effect. The transparent flower shape and its special style give the burnt-out products a high-end and gorgeous feel. Burnt-out products not only have a gorgeous appearance, but also have excellent internal quality. They are wear-resistant, high-strength, easy to wash, quick-drying, and non-ironing, and are welcomed by domestic and foreign markets. The research and application of burnout technology has become popular in the textile printing and dyeing industry in recent years.

6. Wool fabric printing At present, printed wool fabrics are mainly thin plain weave fabrics or gauze fabrics, which are mostly used to make women's shirts, dresses, quilts and skirts. In addition to direct printing, wool fabric printing also includes discharge printing, anti-printing and transfer printing. Wool blended fabric printing also occupies a certain proportion. At present, relief finishing of wool fabrics is also quite popular, mainly used for woolen sweaters.

7. Velveteen printing. Diamond printing takes advantage of the characteristics of silk screen printing to print on velvet, which can obtain a special flash effect that emits the light of natural diamonds under sunlight.

8. Foam printing There are many kinds of special printing on fabrics, and foam printing is one of them. The characteristics of foam printing are: strong three-dimensional effect, similar to artificial embroidery, soft hand feel, wear-resistant, washable, good fastness, elastic, and can be widely used in tablecloths, curtains, tea towels, handkerchiefs, pillow covers, clothing, and travel Souvenirs, etc.

It can be used not only on natural fiber fabrics such as cotton, linen, and silk, but also on man-made fiber fabrics.

9． Flocking printing Electrostatic flocking is a new technology that is currently emerging in the textile industry. It is a product that uses high-voltage electrostatic fields to plant short fibers on gray fabrics. Flocking products have simple technology, strong three-dimensional effect and low cost. Therefore, they are widely used in rubber, plastics, artificial leather, and decorative products. Especially for small batches of tourism products, it shows its incomparable superiority. Using flocking patterns to decorate shoes, hats, children's clothing, trademarks, and clothing will make them unique.

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 printing and dyeing production method with practical significance in waterless processing. In addition to not using water, another major feature is that the paper deforms very little, so it can print fine multi-layered patterns and photographic images. Really transfer the pattern image to the cloth. The effect is sometimes better than ordinary anti-dye and discharge printing.

In addition to the above ten common printing methods, there are also some special printing methods, such as: electrochemical aluminum transfer printing, photoluminescence printing, fluorescent printing, gold and silver powder printing, paint foam printing, color changing printing , Fragrance printing, diamond printing and pearlescent printing, etc., printing methods.

Plastic screen printing

Screen printing of plastic parts is one of the secondary machining (or reprocessing) of plastic products. The so-called secondary processing is to perform surface decoration treatment after injection molding of plastic products, such as: plastic electroplating, plastic spraying, plastic hot stamping, plastic silk screen, etc. The reason why plastic products require secondary processing is mainly determined by the properties of the plastic itself. For example, its dyeability is relatively simple, and its color has poor light fastness. In order to make up for these shortcomings and improve the appearance decoration of plastic products, secondary processing is required.

There are many types of plastic products, but in terms of screen printing methods, flat screen printing is used for sheets and planar bodies; curved screen printing is used for cambered bodies that can be expanded into a plane; and indirect screen printing is used for special-shaped products. Plastic products have different solid resins, additives and molding methods, and their surface properties vary greatly, especially the smoothness, polarity and static electricity of the surface, which have become the root cause of plastic screen printing failures.

1. Screen printing of polyvinyl chloride plastic Polyvinyl chloride (PVC) was put into industrial production in 1931. PVC plastic has the advantages of bright color, not easy to break, acid and alkali resistance, and low price. However, because some auxiliary materials added when making PVC plastic are often toxic, PVC products are not suitable for holding food. PVC films come in a wide variety of colors, and most of the colorful plastic sheets, artificial leather, etc. 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 televisions, calculators and other products as well as many fields of the national economy. ABS plastic is a terpolymer of acrylonitrile, butadiene, and styrene. Since ABS plastic is a terpolymer, it has the same characteristics of the three components. Acrylic acid can make the polymer resistant to chemical corrosion and have a certain surface hardness; butadiene can make the polymer The material has rubber-like toughness; styrene can make the polymer easy to process and form. ABS plastics come in various colors. The products have a glossy appearance, low water absorption, good impact strength and surface hardness within a certain temperature range, and good dimensional stability. Most ABS resins still have considerable impact strength and toughness at -40°C. The use temperature range of their products is -40~60°C. ABS plastics have high molecular weight, good physical properties, and are easy to process, shape, and print. Good adaptability.

3. Screen printing of polyethylene and polypropylene plastics Polyethylene (PE) plastic: Polyethylene plastic is 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 groups, which contains a certain amount of side groups. The more and longer side groups in the polymer chain, the less crystalline the polymer will be.

In other words, the higher the density of polyethylene, the less conducive it is to surface coating. Polyethylene is unclear in a variety of solvents, but when the temperature exceeds 70°C, polyethylene can be dissolved in a small amount in solvents such as toluene and amyl acetate. The properties of polyethylene provide conditions for surface coating. The plastic can be soaked in a heated solvent to swell the surface and destroy some of the crystals to improve the adhesion of the ink film to the plastic surface. The mixture 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℃; use potassium heavy leadate, sulfuric acid and distilled water. The mixed liquid is soaked in polyethylene plastic at 70~75℃, which is beneficial to enhance the adhesion of the ink film on the plastic surface.

Polypropylene (PP) plastic: Polypropylene has been one of the important varieties in the development of plastics for many years. Suitable for all molding methods. It can be made into various pipes, various boxes, films, fibers, etc. Industrial polypropylene has a high degree of spatial regularity and a high degree of crystallinity, with an isomorphism index in the range of 89 to 95. It also contains a small amount of amorphous macromolecular chains with atactic structure and low crystalline stereoblock structure. The melting point is in the range of 170~175℃, the glass transition temperature of isotactic polymer is -13~0℃, while that of syndiotactic polymer is O℃. Concentrated nitric acid and fuming sulfuric acid can etch polypropylene. At higher temperatures, they can be dissolved in aromatic hydrocarbons and chlorinated hydrocarbons, and they can only expand at room temperature. Acids and esters also have some corrosive effects on it. As the isotactic polymer content increases, the solvent resistance also increases accordingly.

In general, polyethylene and polypropylene are polymer materials with non-polar molecular structure and high crystallinity and low surface tension. There are no polar groups such as carbon groups, carboxyl groups, and hydroxyl groups in their molecular structures. Compared with polyethylene, polypropylene surface coating is easier.

4. Screen printing of plastic components of electronic products Electronic products, especially radio products such as radios, tape recorders, televisions, etc., have very high requirements for appearance. Art designers attach great importance to the appearance decoration of products. However, there are currently few processes used for appearance decoration in our country, which limits the ideas of art designers, allowing them to only use the size of the product and the use of various lines. The plastic itself is limited. color to change the appearance of the product. After the development of plastic screen printing, it has brought convenience to the decoration of electronic products. Therefore, in recent years, plastic screen printing of various domestic electronic products has been widely used.

5. Screen printing of plastic signs In recent years, plastic signs and decorative parts that are screen-printed with graphics and text after plastic molding have developed rapidly. For example, screen printing on plastic parts of polyvinyl chloride hard board (PVC board), polycarbonate, ABS, organic glass, and modified polystyrene has been widely used and achieved good decorative effects and economy. benefit.

6. Screen printing of soft and hard plastic parts ① Screen printing of plastic hoses. There are several methods for printing plastic hoses, the main method is thermal transfer printing. Thermal transfer printing method uses sublimation dye ink or other materials to first print graphics and text on transfer paper, then attach it to the substrate, and heat from the back of the transfer paper to sublimate the dye on the paper surface. The image and text are transferred to the substrate. After the plastic hose is surface-treated, the transfer paper passes between the hose and a heated iron plate. The heated iron plate pushes the transfer paper towards the hose, and the heating completes the transfer. After transfer, the hose enters the drying device, and the drying temperature is generally around 65°C. ②Silk screen printing of soft plastic. Soft plastics are mostly used to make toys, such as inflatable cartoon toys. During production, the pattern is usually screen-printed on soft sheet plastic, then cut and heat-synthesized. The thickness of the material used is generally 0.8~3.0mm. If more than two colors are screen printed, most plastics will expand and contract, resulting in registration errors between the second color and the first color. This color registration error causes the product to lose its original value and cannot be put on the shelves as a qualified product. For this reason, there is no other way to perform multi-color printing than using a long printing press that can fix soft plastics. When printing on a long stage, the substrate must be fixed with adhesive. It is worth noting that toy printing must use non-toxic and harmless inks stipulated in relevant standards. ③Silk screen printing of hard plastic products. There are two types of rigid plastic products: rigid boards and molded products.

This ink is different from ordinary inks in that it will adhere firmly to the aluminum plate and also has good light resistance. It is an ideal ink for screen printing aluminum anodized signs.

3. Silk-printed convex-concave colored aluminum signs The convex-concave signs are characterized by painting in the concave areas. They have good wear resistance and have a three-dimensional effect. They are mostly used for mechanical nameplates and company plaques. The traditional production method is to manually paint the corroded recesses (or inject paint with an injection needle), and then trim them by hand to remove the residual paint on the edges. This method is not only time-consuming, inefficient, and requires skilled operators, but the signs produced often have unclear edges, deformed handwriting, and unstable quality. Therefore, we are limited to producing some signs with small batches, few colors, low quality requirements and very simple patterns.

4． Silk-screen sandblasting and oxidized paint-embedded aluminum signage The silk-screen sandblasting and oxidized paint-embedded aluminum signage process is a traditional signmaking process. This type of product has a silvery white appearance, high surface hardness, and good wear resistance.

5. Silk-printed wood alumina sign Water white alumina sign is a new type of matte surface sign that has recently appeared in my country. This kind of sign has a milky white appearance, smooth surface, no concave and convex feeling, and is resistant to moisture and heat, salt spray, and mold. It also has strong resistance to sunlight, abrasion, and organic solvents, and is suitable for applications that require frequent wiping. Machine tools and complete machines working in harsh environmental conditions. What's even more valuable is that the production process of silk-screen water-white alumina signs is low, the work efficiency is high, and there is basically no "three wastes" produced. Its consumption of manpower and energy (including water and electricity) does not exceed one-third of traditional corrosion signs.

6. Printed aluminum oxidation color sign Aluminum flat anodized sign is one of the sign varieties and is widely used. It has the characteristics of beautiful appearance, brightness, high hardness and good wear resistance. In the past, the process included aluminum plate blanking, mechanical polishing, chemical polishing, and oxidation; indirect method screen printing, thick zinc-barium white paint and alkyd varnish for protective printing; and dye paste for coloring. Regardless of screen printing or dyeing, this process has the disadvantages of using a lot of materials, complex processes, low printing durability, poor resolution, and high cost. Under the existing technical conditions, it is possible to develop a new process with relatively simple procedures, good quality and high efficiency. The new process uses non-toxic diazo photosensitive adhesive to directly produce screen printing plates. Practice has proven that it can meet the requirements of fast plate making, high resolution, high printing durability and less material use. Moreover, the processes of printing protective paint, dyeing, and deprinting materials can be combined into one, that is, self-made water-based dyeing printing materials, direct dyeing, and continuous color registration, without the need for a color tank. This greatly simplifies the entire process and operating procedures, and provides a new method for flat oxidation dyeing signs.

7. High-gloss three-dimensional embossed aluminum signage With the continuous development of production technology and the improvement of people's material and spiritual living standards, people not only have higher and higher requirements for the function of the product, but also for the shape and shape of the product. Pretending also puts forward higher requirements. Especially with the development of domestic and foreign market economies and the continuous expansion of foreign trade, people have increasingly higher requirements for product functions and external quality. In order to improve the market competitiveness of products, high-gloss three-dimensional relief signs for high-end products have been widely used.

8． Silk screen electroplating plaque Plaque is a product produced by many sign factories. Plaques are mainly made of metal materials, which require solemnity, obviousness, and strong decoration. Among traditional metal plaques, square plaques with brass floors, corroded characters, and black paint are the most common. With the continuous changes in people's aesthetic views and the gradual development of the commodity economy, there are new and different requirements for the quality of plaques. Since the sign industry introduced screen printing technology, it not only promoted the development of screen printing technology, but also provided technical means for the sign industry to develop new products. The new type of electroplating plaque made by silk screen printing method is the product of the combination of sign electroplating and silk screen printing technology. Its basic method is to screen-print plain text graphics on a copper plate, use an ink layer to protect and cover the non-graphic parts, and electroplat the silver parts of the graphics with a copper, nickel, and chromium system, and then perform mechanical shaping and protection processing.

9． Imitation metal etching screen printing Products imitated by metal etching printing have a visual effect of metal etching. In order to achieve the above effects, the surface of the substrate should have a mirror gloss.

A concave and convex ink coating is printed on the substrate with transparent ink, forming a frosted glass-like rough surface. The combination of rough surfaces with strong contrast makes the printing surface concave, and the mirror surface produces a convex printing effect. The stronger the contrast, the better the imitation etching effect. The concave and convex effect is proportional to the thickness of the ink coating. The ink has a high solid content, and the effect will be better if a low-mesh printing plate is used. This technique initially uses acrylic emulsion (solid content 50) gel-like ink, which is heat-treated at 180°C after drying. Therefore, the substrates are limited to heat-resistant metals and glass, and hard plastics and paper cannot be used. Due to the use of highly viscous gel inks such as acrylic emulsions and the temperature during operation, the stability of the ink viscosity is extremely poor, and the quality of the product fluctuates greatly. Since the use of ultraviolet drying inks in screen printing, printing processes and techniques have gained great flexibility. UV ink is a 100-degree curing type. The ink can be hardened by ultraviolet irradiation for 3 to 5 seconds, during which the surface temperature is about 100°C. If a water-cooled UV irradiation machine is used, the temperature can be lowered to about 60°C, and the types of substrates will also increase. It can be used on aluminum foil paper with mirror gloss, evaporated paper, evaporated vinyl chloride film, and evaporated polyester film. Print on other materials.

10． How to screen-print conical scales: First, screen-print the graphics and text onto the transfer rubber, then install the conical parts on a homemade special fixture, and then roll them over the transfer rubber, so that the graphics and text are Transferred to the conical part.

11. Imitation porcelain anodized signs have a enamel-like surface with soft luster, good resistance to corrosion, high hardness and wear resistance, good thermal insulation and electrical insulation, good covering ability and The ideal adsorption capacity makes it a good decoration for instruments and meters, especially for high-end machines. However, gas containing chromium escapes during the production process, so the operating equipment should be equipped with good exhaust and ventilation equipment to avoid poisoning. The surface pretreatment method of oxidized porcelain signs is basically the same as that of screen-printed, sandblasted and oxidized inlaid paint signs, except that oxidized porcelain signs generally do not require chemical polishing and are directly oxidized. The punching processing of imitation porcelain oxidation corrosion signs, imitation porcelain oxidation dyeing signs and imitation porcelain oxidation printed signs is generally carried out before oxidation. The oxidation process of imitation porcelain oxidation corrosion signs is the same as the sandblasting oxidation inlay paint process, and the oxidation dyeing process of imitation porcelain signs is the same as that of screen-printed aluminum oxidation color signs.

Screen printing of ceramics

The methods that have long been used for pattern decoration on ceramics are blow-jet, hand-painted, rubber stamping, and decals printed with copper plates and lithographs transfer printing and other methods. In recent years, with the application of screen printing in the ceramic industry, the decorative patterns on ceramics have become more three-dimensional. The fired glaze is very thick and the color is very bright, and it looks like it was painted with enamel. The pattern is more delicate than the pattern generally using the blow-jet method, and the production efficiency is also much improved. Since silk screen printing has many of the above-mentioned advantages for the decoration of ceramics, its application scope is becoming wider and wider day by day.

Glass screen printing

Glass screen printing is to use a screen printing plate and glass glaze to perform decorative printing on glass products. Glass glaze is also called glass ink and glass printing material. It is a paste printing material mixed and stirred by coloring materials and connecting materials. The coloring material is composed of inorganic pigments and low melting point flux (lead glass powder); the binding material is commonly known as suet in the glass screen printing industry. The printed glass products must be placed in a furnace and fired at a temperature of 520~600°C. Only then can the glaze printed on the glass surface be solidified on the glass to form colorful decorative patterns. If silk screen is used together with other processing methods, more ideal results will be obtained. For example, using polishing, engraving, etching and other methods to process the glass surface before or after printing can double the printing effect.

1. Glass products etching and screen printing For a long time, the etching decoration of glass products has been to heat-coat a layer of wax and other reinforcing materials on the surface of the glass as a resist layer, and then use a needle, knife, etc. to carve patterns on the coating to expose the glass. The surface is then etched with hydrofluoric acid on this part.

Its advantages are mechanical wear resistance, chemical corrosion resistance and easy decontamination. In addition, in order to color the glass during design, organic coatings can be printed on the back. Since the back cannot be directly contacted, it is highly durable and has a large choice of inks.

6. Matte screen printing on the glass surface. Use a screen printing plate to print the matte ink on the glass surface (produced in Belgium) on the soda-lime glass. Wash it with water after a few minutes. The effect will be like brown glass. Hydrofluoric acid is usually used when etching glass, which is dangerous. This kind of ink does not contain strong acid and is easy to operate. Its matting effect is similar to that of etching.

7. Silk screen printing of electric heating defogging devices. In order to prevent condensation of water vapor on the rear window glass of automobiles, more and more electric heating defogging devices are printed. This silk screen printing method involves applying silver paste into lines on smooth glass and firing it while bending the glass. When the rear window is blurred and fogged, the lines are heated by electric current, which increases the temperature of the glass surface and removes water vapor. When this kind of electrothermal defogger device is powered on, some cars do not use a manual switch, but automatically power on and off. The sensor of this automatic device is to screen-print serrated electrodes on thin plate glass, and then cover it with a layer of moisture-sensing body, using the humidity ratio to automatically control power on and off.

8. Silk screen printing of liquid crystal display components Liquid crystal digital display components are spaced about 10μn apart. It is made by sealing the surroundings of two thin glass sheets, injecting liquid crystal, and sealing the injection port. On the surfaces of these two pieces of glass, transparent conductive strands in the shape of an "8" are silk-printed. This "8" consists of seven parts, which can partially increase the voltage to display the numbers (0~5). The process of making this "8"-shaped pattern is to first screen-print only the "8"-shaped part with acid-resistant ink on the field glass with the entire electrically conductive strands, and then etch it with acid to remove the unused parts. Printing part of the conductive strand. Screen printing in electronic product manufacturing In the production process of electronic products, screen printing has become an indispensable process. Such as product shell decoration, printed circuits, thick film integrated circuits, solar cells, electricity; capacitors, piezoelectric components, photosensitive components, thermal components, liquid crystal display components, etc., are all used to varying degrees in the production process. Screen printing process.