Application of general-purpose compound ink in flexible packaging

Plastic gravure inks are generally classified into table printing inks and composite printing inks. The so-called general-purpose composite inks refer to composite inks that can be used on various films. The applicable films include processing polyester (PET) film and processing nylon (NY Films, processing biaxially oriented polypropylene film (BOPP), K-coated film (KOP), cellophane (Pr), etc.

In general, general-purpose composite inks use polyurethane resin, and others use polyvinyl butyral (PVB) resin. This article only discusses polyurethane type, such inks can be used for frozen food packaging, dry food packaging, portable packaging, hydrous food packaging, boiling foods and high temperature cooking food packaging. In most cases, only one component can be used (ie, no curing agent is added). In some cases, it is necessary to add 2-4% of curing agent, such as frozen food storage temperature below -18 °C, nylon film above 100 °C cooking packaging and other needs to improve the composite strength and chemical resistance of the occasion.

Because this type of ink can be used for cooking purposes, it is also known as cooking ink or nylon ink. However, special attention should be paid to the fact that not every color can be used for cooking. Since some pigments, especially red, yellow, and orange, will migrate at high temperatures and pressures, be sure to read the instructions of the ink carefully when cooking bags. Yip's ink (Zhongshan) company's general-purpose composite ink for the GLP series. In order to prevent such phenomena from happening, the colors of inks that are not resistant to cooking and boiling are specifically marked as light packages on GLP series ink packaging drums.

Its compounding method is also very extensive, and it can be applied to dry compounding, solvent-free compounding and extrusion compounding. Because the adhesiveness of the ink polyurethane to the OPP film is poor, therefore, if the PP is to be squeezed, the white color must be changed to chlorination. Polypropylene-type printing compound ink. As for dry compounding, if it can be recombined after printing for 8-24 hours, the composite strength can be greatly improved.

The above is a general overview of general-purpose compound inks. Here are some more specific applications: These inks can also be used for the printing of polyvinyl chloride (PVC) film. Do not use PVC ink instead of general-purpose ink, but pay attention to control the dilution solvent in the addition of ketones, too little ink solubility is poor, too many easy to break the film, generally 20% of the dilution solvent is appropriate. Once there was a printing factory printing "Hainan coconut sugar" packaging, because the general table printing ink could not bear the odor of sugar, the adhesion became worse. According to our recommendation, PVC is printed on the surface of such inks and then covered with a two-component varnish, which successfully prevents the occurrence of similar accidents.

General-purpose inks are also widely used in transparent packaging. In dry food packaging, many structures are composite aluminum-plated packaging. In order to reflect the aluminum-plated metallic luster, many customers use transparent compound inks. The chlorinated polypropylene system is non-polar. There are many solvents, many dyes are insoluble in this system, so the color of transparent ink is not complete. Although the general-purpose ink has a slightly higher cost, it has a wide variety of colors and higher transparency, so it has been widely used, but the application of clear ink should be used with caution. First, pay attention to the odor, because the odor can lead to the quality of the entire batch of products, And re-oven does not eliminate the generation of odor. The second is the composite strength. The type and color of the dye have a great influence on the composite strength. As for some other matters needing attention: If it is easy to be dissolved by glue when it is dried, and it is easily dissolved by the sub-solvent when the AC coating agent is squeezed, it needs to cooperate with the process when printing and compounding.

There are also some manufacturers to slightly improve the general-purpose composite ink, or add two-component coating varnish, or add anti-wear additives in the ink used in table printing resistant milk packaging, will not be described in detail here.

In a word, general-purpose composite inks are widely used in flexible packaging. They can be used not only for printing composite inks, but also for table printing inks. Some applications are beyond the recommended range of the ink factory and are often surprising.

Source: Graphic Arts Master