Gravure ink procurement

The purchase of raw materials is an important part of the company's economic benefits. The quality of raw materials is the key to directly affect product quality. In packaging and printing raw materials, ink quality and technical performance are the most important factors affecting the quality of packaging materials. Therefore, the purchase of ink is a major link that will directly affect the company’s profit and loss and reputation. Here are some analyses of gravure ink purchases.

Supplier selection

The selection of supply companies must be based on the internationally accepted IS09001 quality assurance system requirements. Because the printability of inks is related to the ambient temperature and humidity, the choice of ink supply companies must consider the climate gap, and priority should be given to companies with geographical proximity. First, try the ink and draw conclusions based on the opinions of the technology, production staff, and customers. If the requirements are met, supply personnel and technical personnel are organized to invite customer representatives to conduct on-site inspections with multiple ink manufacturing companies. The specific contents include: production site, product performance, research and development capabilities, and customer satisfaction. According to "Quality First, Price Purchasing", fixed-point procurement is achieved. The inspection of qualified suppliers shall be conducted every two years. The main assessment is product quality, technical performance, price, delivery time, technical service, and customer satisfaction. The assessment team shall consist of technology, production, supply, sales, and customers. Representatives and senior management staff. In particular, it focuses on inspecting the suppliers' technical services and communication capabilities. It can actively participate in the resolution of print quality problems and can assume its due responsibilities. We must pay attention to the importance of ink quality in packaging and printing, and strengthen the management of ink production companies as a first-class customer to achieve a win-win development in the value chain.

Applicability of ink

When purchasing inks, first consider the suitability of the ink.

Printing substrate

Different resin printing substrates should use inks with different resin systems. The commonly used printing substrates include BOPP film, BOPET film, BOPA film, and PE film. According to the "similar compatibility" principle, only the matrix resin is similar or similar, and the printing substrate and the ink will have good adhesion. In the ink system, the binder resin plays a key role in adhesion. Gravure inks currently developed are classified into benzene solvent type inks, alcohol solvent type inks, and water solvent type inks. According to the binder resin is divided into chlorinated polypropylene ink, polyester ink, polyamide ink and so on. The chlorinated polypropylene ink is suitable for the printing of BOPP film. The polyurethane ink is suitable for the printing of BOPET film and BOPA film, and can be used for high-temperature cooking and boiling. The polyamide ink is suitable for the surface printing of BOPP film and PE film.

Printing process conditions

The printing process conditions include the printing speed (line speed), drying capacity, plate roller performance, gravure printing mode (surface printing, in-print printing), printing color number, printing sequence, ambient temperature, humidity, and the like. The process conditions directly affect the ink transfer rate, drying speed, etc.: Therefore, the ink should be selected reasonably and economically according to the process conditions. For example, when the humidity on the production site is high and the printing speed is high. Use high-grade ink with high transfer rate and fast drying speed to prevent the film from sticking after printing. Under the conditions of air drying and high printing speed, the ink with high viscosity and antistatic agent is used to avoid quality problems caused by static electricity.

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Printing effects include the hue, glossiness, transparency, hiding, leveling, overprint accuracy of printed products. Different ink manufacturers have some differences in terms of hue, solid content, viscosity, glossiness, level expression, etc. Even the ink produced by different manufacturers of the same batch is not the same. Therefore, when doing the same product, after obtaining the customer's approval of the sample draft, as much as possible to purchase the same batch of ink as much as possible to ensure consistency with the sample.

After the printing process, the plastic film has to be processed through extrusion, compounding, dry compounding, vacuum aluminum plating, slitting, and bag making. When the customer makes it, it must undergo high-temperature cooking, boiling, freezing, and sterilization. And other processing. Therefore, the ink should be selected according to the post-printing process conditions and application conditions of the packaging materials. For example, when performing dry compounding, the adaptability of the ink and adhesive in the ink should be considered, and the peel strength of the compounded product should not be affected. In the process of bag making, high-temperature cooking, boiling, freezing, etc., the high and low temperature resistance of the table printing ink should be taken into account, and the fillers that prevent the separation of the ink film and discoloration should not be added.

The economics of ink

The economics of ink include not only the purchase price but also the purchase quantity. According to the demand for materials provided by the production department and the "raw materials consumption quota" compiled by the technical department, the amount of ink purchased will be calculated. While achieving economic procurement as much as possible, it is also necessary to reduce the use cost based on actual production conditions. Because inks, especially toners, are different from other raw materials, once they are left over, it is very difficult to use them again and they have to give up and waste. Achieving closer to zero inventory not only reduces the occupation of funds, but also selects the bias of the original color ink according to the customer's requirements, ensuring that the hue of the printed products is consistent. For example, the primary colors of red are partial red and purple, and the primary colors of blue are partial sky blue and partial purple. The primary yellow points are greenish and red. When it is impossible to artificially control the temperature and humidity of the site environment, inks containing different additives need to be selected for different on-site environments, thereby reducing the increase in usage costs caused by the temporary addition during the printing process. The ink is required to have a certain anti-static property, prevent the electrostatic adsorption of air generated by the friction with the plate roller, as well as foreign matter such as hair, dust and the like in the environment, resulting in print quality problems. Packaging and printing companies should strengthen communication and understanding with ink production companies, let ink production companies fully understand their own printing equipment, including printing speed, printing substrates, drying methods and capabilities, on-site environment, composite adhesives, end-customer requirements As well as packaged products, etc., it is beneficial to formulate suitable inks. In addition, in order to achieve product quality controllability and traceability, each batch of ink must be manufactured and quality inspection, including viscosity, fineness, solid content, appearance and other items.