Screen Printing Types and Applications (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 silk screen printing, advertising decoration silk screen printing, Metal advertising board screen printing, stainless steel products screen printing, light reflector screen printing, silk screen transfer aluminum, screen printing and lacquer screen printing and so on.

Textile printing

Fabric printing refers to the process of forming a pattern on a fabric by printing. Printing methods include: type printing, screen printing, drum type circular screen printing, transfer printing, and multi-color printing and other methods, wherein the screen printing comes from the type printing (including type paper and zinc plate), By manual operation, gradually semi-automated, fully automated, and later peaceful network development to the rotary screen type.

There are several printing methods for fabric printing:

1. Paint directly printed. The direct printing of the paint is to directly print the prepared printing paste onto the fabric. This is the simplest and most commonly used process in the printing process. Paint direct printing process generally refers to white or light-colored fabric printing, it is easy to spell color, the process is simple, after printing can be processed by bake, apply a variety of fiber textiles. The paint direct printing process can be classified into Accraming F-type adhesives based on the currently used adhesives. Acrylic adhesive, styrene-butadiene emulsion and chitin adhesive are three direct printing processes.

2. Silk printing. The main methods of silk printing include direct printing, discharge printing, and dye printing. The direct printing method has already been introduced. The method of discharge printing, transfer printing, and osmotic printing will be introduced separately in the following subsections. Here, the anti-inking printing method is mainly introduced.

3. Knitted underwear printing. The main application of knitted underwear printing is paint direct printing technology. After fabric printing, it can be double-baked or dried naturally to avoid problems such as easy deformation of wet processing of knitted fabrics and difficulty in wet processing of agricultural films. The printing method is mainly based on flat screen printing, and is divided into manual scraping and machine operation. This printing method can adapt to pattern patterns of various composition forms and organizational structures, and is suitable for production needs of small batches and multiple colors.

4. Discharge printing. Discharge printing, also known as stencil printing, refers to the use of discharge agents printed on colored fabrics, to destroy some of the pigment has been dyed, and thus obtain a variety of patterns, patterns of printing. Dispensing agents are chemicals that decolorize the dyed bottom. Such as: hanging white, stannous chloride and so on. This method can be divided into white (pull white) and pattern is colored (pull) two. The latter dyeing method makes the fabric pattern fine, but the process is complicated and the cost is high.

5. Silk screen burnt. The burn-in system uses two kinds of fiber blended fabrics with different acid resistance. After the acid burn-in paste printing and chemical processing, the acid-resistant natural fibers are partially rotted, exposing acid-resistant chemical fibers to form crystal clear flowers. Type, its special style makes burnt-out products with high-grade and beautiful feeling. Burnt-out products are not only beautiful in appearance, but also have excellent internal quality. They are wear-resistant, high-strength, good-cleaning, quick-drying, and non-ironing. They are welcomed by domestic and foreign markets. The research and application of burnt-out technology has prevailed in the textile printing and dyeing industry in recent years.

6. Wool fabric printing. At present, the printed wool fabrics are mainly thin plain fabrics or voile fabrics. Most of them are used to make women's shirts, dresses, quilts and skirts. In addition to direct printing, wool fabric printing also includes printing, anti-printing and transfer printing. Wool blend fabric printing also occupies a certain percentage. At present, the embossing of wool fabrics is also popular and is mainly used for woolen sweaters.

7. Velveteen printing. Diamond printing utilizes the characteristics of silk screen printing on velveteen to obtain a special flash effect that can emit natural diamonds under sunlight.

8. Foam printing. There are many kinds of fabric special printing, foam printing is one of them. Foam printing is characterized by: strong three-dimensional impression, similar to artificial embroidery, soft to the touch, wear-resistant, washable, fastness, good elasticity, and can be widely used in tablecloths, curtains, tea towels, handkerchiefs, pillow covers, clothing, travel Souvenirs and other aspects. It can not only be applied to natural fiber fabrics such as cotton, hemp and silk, but also can be applied to artificial 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 top of a grey cloth. Flocking products have a simple process, strong three-dimensional effect and low cost, so they are widely used in rubber, plastics, artificial leather, and decorative products, especially for small-batch tourism products. The use of flocking patterns on shoes and hats, children's wear, logos, and apparel will make it look unique.

10. Transfer printing. Transfer printing is a printing process that accomplishes the coloring effect by relying on the sublimation of the dye and the effect that the dye vapor has on the diffusion and affinity of the fibers. Transfer printing is a kind of printing and dyeing production method that is more practical in water-free processing. In addition to not using water, one of the main features is the small paper deformation, so you can print fine multi-level patterns and photographic images. Really transfer the picture of the pattern to the cloth. The effect is sometimes better than general anti-discharge printing.

In addition to the above ten kinds of common printing methods, there are some special printing methods, such as: transfer of aluminum foil printing, photoluminescent printing, fluorescent printing, gold, silver powder printing, paint foam printing, color printing, fragrance printing, diamond printing and Pearl printing, etc., printing methods.

Plastic screen printing

Screen printing of plastic parts is one of the secondary mechanics (or reprocessing) of plastic products. The so-called secondary processing is after the plastic injection molding, and then a surface decorative treatment, such as: plastic plating, plastic spraying, plastic hot stamping, plastic screen printing and so on. The secondary processing of plastic products, therefore, is mainly determined by the properties of the plastic itself, such as its relatively uniform dyeability, and the poor lightfastness of the colors. In order to make up for these disadvantages and improve the appearance of plastic products, secondary processing is required.

A wide variety of plastic products, but for the silk screen method, the sheet and flat body with a flat screen printing method; can be developed into a flat curved surface curved screen printing method; special-shaped products are used indirect silk screen method. The differences in the surface properties of plastic products, including the solid resins, additives, and molding methods, are especially the smoothness, polarity, and static electricity of the surface, which is the root cause of the failure of plastic screen printing.

1. PVC screen printing. Polyvinyl chloride (PVC) was put into industrial production in 1931. PVC plastic has bright color, not easy to break, acid, alkali, low cost and so on. However, due to the fact that some auxiliary materials that are added during the manufacture of PVC plastics are often toxic, it is inappropriate for PVC products to hold foods. Polyvinyl chloride film variety of colors, commercially available colorful plastic cloth, artificial leather, etc. are mostly PVC products.

2. ABS plastic screen printing. ABS resin plastic is an engineering plastic. In recent years, it has been widely used in televisions, calculators and other products and in many areas of the national economy. ABS plastics are terpolymers of acrylonitrile, butadiene, and styrene. Because ABS plastics are terpolymers, they share the common characteristics of three components. Acrylonitrile can make the copolymer chemically resistant and have a certain surface hardness; butadiene can make polymers have rubbery toughness; styrene can be The polymer has easy processing and shaping properties. ABS plastics have a variety of colors, 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 at -40°C and exhibit toughness. The product's operating temperature range is -40 to 60°C. ABS plastics have high molecular weight, good physical properties, easy processing, and printing. Suitability is good.

3. Screen printing of polyethylene, polypropylene plastics.

Polyethylene (PE) Plastics: Polyethylene plastics are used for a wide range of applications and can be manufactured in a variety of finished products through extrusion, injection, and other molding processes. The polyethylene molecule is a long chain of methylene groups containing a certain amount of pendant groups. The more and more side groups in the polymer chain, the lower the crystallinity of the polymer. That is, the higher the density of polyethylene, the more unfavorable the surface finish. Polyethylene is not clear in many solvents, but when the temperature exceeds 70°C, the polyethylene can be dissolved in a small amount in solvents such as toluene and amyl acetate. The nature of polyethylene provides conditions for surface finishing. The plastic can be soaked with a heating solvent to swell the surface and destroy part of the crystallization to increase the adhesion of the ink film on the plastic surface. A 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 rapidly destroy polyethylene at 90-100°C; use heavy lead potassium, sulfuric acid and distilled water The mixed liquid, soaked in polyethylene plastic at 70-75°C, is conducive to enhancing the adhesion of the ink film on the plastic surface.

Polypropylene (PP) Plastics: Polypropylene has been one of the important varieties of plastics for many years. Suitable for all molding methods. Can do all kinds of pipe, all kinds of box and film, fiber and so on. Industrial polypropylene has a high degree of spatial regularity, a high degree of crystallinity, and an isotropic index in the range of 89 to 95%. It also contains a small amount of macromolecular chains of amorphous atactic and low crystalline stereoblock structures. The melting point is in the range of 170-175°C, the glass transition temperature isotactic polymer is -13 to 0°C, and the syndiotactic polymer is O°C. Concentrated nitric acid and fuming sulfuric acid are capable of attacking polypropylene. At higher temperatures, they can be dissolved in aromatics and chlorinated hydrocarbons. At room temperature, they can only swell. Acids and esters also have some dissolution effects on them, and as the content of isotactic polymers increases, the solvent resistance increases accordingly.

In general, polyethylene and polypropylene are high-molecular materials with high crystallinity and low surface tension and non-polar molecular structures. There is no polar group such as carbon group, carboxyl group or hydroxyl group in their molecular structure, and the surface finish of polypropylene is easier to be compared with polyethylene.

4. Screen printing of plastic parts for electronic products. Electronic products, especially radio products such as radios, tape recorders, televisions, etc., have very high requirements for appearance. The designers of the art design attach great importance to the appearance and decoration of the products. However, the current technology used for exterior decoration in our country is limited, which limits the thinking of the artists and enables them to pass only the size of the products and the use of various lines. The plastic itself is limited. The color to change the appearance of the product. Since the development of plastic screen printing has brought convenience to the decoration of electronic products, plastic screen printing of various electronic products in China has been widely used in recent years.

5. Screen printing of plastic signs. In recent years, plastic signboards and plastic molding components with silkscreen graphics have developed rapidly. For example, the screen printing on polyvinyl chloride rigid board (PVC board), polycarbonate, ABS, plexiglass, modified polystyrene plastic parts, has been widely used, and achieved a good decorative effect and economy benefit.

6. Screen printing of soft and hard plastic parts.

1 silk screen of plastic hose. There are several methods of printing plastic hoses, the main method of which is thermal transfer printing. The thermal transfer method uses sublimation dye ink or other materials to print the image on the transfer paper first, and then paste it together with the substrate and heat it from the back of the transfer paper to sublimate the paper surface dye. Graphic transfer to the substrate. After the plastic hose is surface-treated, it is passed between the sun gas and the transfer paper from the hose and a heated iron plate. The heated iron plate pushes the transfer paper to the hose and heats up the transfer. After transfer, the hose enters the drying device and the drying temperature is generally about 65°C.

2 soft plastic screen printing. Soft plastics are used to make toys, such as inflatable cartoon toys. When the production is usually first on the soft sheet plastic screen printing pattern, then cut, hot synthesis type. The thickness of the material used is generally 0.8-3.0 mm. If screen printing with more than two colors is performed, most of the plastics will expand and contract, resulting in color misregistration between the second color and the first color. This trapping error causes the product to lose its original value and cannot be placed on the shelf as a good product. For this reason, multi-color printing can only be achieved with long presses that can hold flexible plastics. For long printing, the substrate should be fixed with an adhesive. It is worth noting that toy printing must use non-toxic and harmless inks in accordance with relevant standards.

3 Screen printing of hard plastic products. Hard plastic products are two kinds of hard plates and molded products. Tickets, signs, instrument dials, cosmetic containers, etc. are all made of hard plastic.

7. Screen printing of the instrument panel. The surface material of the panel may be metal, various plastics and paints, etc. The appropriate ink is used to print some texts and graphics on the panel to indicate some functions of the instrument and equipment, and also to beautify the panel. Screen printing text and graphics require clear, good adhesion, wear resistance, but also requires soft and elegant colors, giving people a sense of beauty. Here we mainly discuss how to use screen printing process to improve the quality of the panel.

9. Screen printing of colored polyester labels. Polyester label is a new type of signage developed rapidly in recent years in China. Because it has the advantages of colorful, decorative, easy to paste, simple manufacturing methods, low cost, etc., it is welcomed by the majority of users, and quickly obtained in high, medium and low-grade electronic products, household appliances, and stationery. Popular applications. At present, there are many specialized factories in the country that produce such signs. However, because the production processes of these factories are all designed in accordance with the needs of high-volume label processing, it is impossible for those polyester brand products with many varieties and small quantities to be viewed either in terms of processing technology or production cost. adapt. Here is a process technology that uses screen printing to print colored polyester labels for reference in the production of small-lot, multi-colored colored polyester signage producers.