The Development of Indian Printing Ink Improves Environmental Protection

Tinplate is the common name for tin-plated cold-rolled steel sheet in the packaging industry. It used to be divided into hot dip tinplate and electroplated tinplate. In the development of tinplate production, lowering the production cost of tinplate is a strategic goal of the manufacturer. Therefore, by the 1970s, the hot dip tinplate was eliminated due to large consumption of tin. With the advancement of can manufacturing technology, people's demand for metal containers has increased. In the 1990s, the main varieties used for electroplated tinplate include: CC steel grades, large-size coarse-grained iron, low-tin or chrome-plated cold-rolled steel sheets, and secondary cold-rolled steel sheets with 0.14 to 0.18 mm thickness. The appearance of these types of tinplate not only reduces the cost for manufacturers and can users, but also more importantly meets all types of cans such as resistance welding tanks, adhesive cans, DRD cans, and DI cans, as well as crown caps and caps. Needed to provide necessary packaging materials for packaging of metal containers for industries such as canned foods, beverages, oleochemicals, household chemicals, pharmaceuticals, culture and education supplies, and cosmetics.

The various types of tinplate mentioned above can generally be marketed as products after being decorated with printed iron. In China, printed iron refers to external printing, and coating refers to internal coating. The outer coating of the inner coating ensures that the tinplate has good canning, canning and decorative appearance. However, the thickness of this coated organic film is usually only a few microns thick, and it is difficult to completely cover the surface of the tinplate. Therefore, in order to prevent the occurrence of concentrated corrosion in organic film defects, tinplate must be required to have high corrosion resistance, surface oxide film to provide dense coating, surface oil layer to ensure the leveling of the coating film. For this reason, in the late 1990s, tinplate makers developed and invented "laminated iron" for hot PET film. However, tinplate, chrome-plated iron, and laminated iron cannot be separated from high-quality inks and coatings.

Iron printing ink must have the following characteristics:
â—Ž Heat resistance: The ink must have good adhesion with tinplate after being cured by heat, and the pigment does not change color after baking.
â—ŽProcessability: Can withstand bending, stamping, drawing, etc.
â—Ž Lead-free: The ink components do not contain lead.
â—ŽDrying: Generally 1% desiccant has been added to the ink in the ink factory. It is necessary to add 1~2% desiccant when printing, but it should not be too much, otherwise the ink is easy to crust when coating. Overbaked.
â—Ž Wet imprinting: No ink loss, fading, and coloring are found.
â—Ž High-temperature sterilization: The ink does not change when the canned food is sterilized.
â—Ž lightfastness, weather resistance: especially when the metal container ink coating (without the surface coating) is particularly important.
透明 Transparency: When the metal surface gloss is used as a printing body, the transparency of the ink is very important.
â—Ž White Ink: Primer on the metal surface and then coat it.

Printing iron decorating paints are classified by resin system as oily, phenolic, epoxy, vinyl, polyester, acrylic, amino and other resins; inner coating, outer coating, white coating, and glazing coating are classified according to use. The general anti-sulfur coating is a zinc oxide oleoresin, the acid-resistant coating is an epoxy phenolic resin, a glazing coating, and the white coating is an acrylic resin or a polyester resin. The above-mentioned various types of coatings and inks are coated on tinplates and become metal containers. However, due to the release of a large amount of solvent gas during the high-temperature baking process, the paint has obvious odor and the concentration of benzene-containing gas is exceeding the standard, causing serious pollution to the environment. Therefore, while developing tinplate printing technology, the environmental protection of waste gas treatment cannot be ignored. Foreign countries have a long exploration process for this waste gas treatment, which consumes a lot of manpower and financial resources. From the high-altitude emissions of the 1960s, the adsorption method of the 1970s (high cost and incompleteness), and the catalytic combustion method of the 1980s (high cost), there was only a thorough solution to the incineration method in the 1990s. Nowadays, there are research institutes and manufacturers of environmental protection equipment in the country that are committed to the research of the aforementioned exhaust gas treatment. The realization of catalytic combustion and incineration brings good news to the printing iron industry. In particular, the incineration method not only makes up for domestic gaps, but also reduces the operating costs of waste gas treatment and has broad market prospects.

According to the preliminary statistics of China's printing industry, there are nearly 1,000 printing and coating lines. Among them, the coating drying room with serious exhaust gas pollution accounts for about 1/2, each coating drying room has 214 coating tinplate in the smallest production size (512×721mm), the coating thickness is 5.5 g/m2, and the production speed is 4600 sheets/hour. To calculate, about 20kg of waste gas will be discharged every hour. Every day, 15 hours (second class), 300kg of waste gas will be discharged. Therefore, the degree of environmental pollution can be imagined. In view of this, China Packaging Technology Association has set up a designated factory for environmental protection equipment in Shanghai. It specializes in the development and production of incinerators to solve the problem of exhaust gas pollution that has not been solved in the printing iron industry for many years. This has given the tinplate packaging industry even greater support and expansion. Prospects.