Usability of straw for secondary packaging printed by offset and gravure printing techniques

Packaging is the material with which the product is wrapped or inside which the product is placed. The main function of packaging is to protect the packaged product, identify it and place it on the market, and to ensure the original shape of the packaged goods. The trend today is to reduce the global amount of packaging waste by recycling the same waste or reusing other available waste materials, while maintaining the required quality of the packaging thus produced. Cereal grains which include wheat, rye, barley, oats, rice, corn, millet, sorghum, wheat, spelt and others, are staple foods for human and animal consumption. Each year, large quantities of stalks are left in the fields after harvesting, and after drying in the sun is mostly treated as waste. Given the high availability of cereals worldwide, cereal straw could be more usefully utilized as an alternative source of fiber for secondary packaging. Therefore, the printing paper substrates were formed from the straw pulp of three different cereal species (wheat, barley and triticale) and mixed with recycled wood pulp in a 3:7 ratio. Since offset and gravure printing are used globally to print absorbent packaging, in this study we analyzed the black prints made by these two printing techniques. The usability of the printed papers with straw pulp for secondary packaging was observed based on the penetration of the ink into the printing substrate. It was found that the composition of the paper substrate has no effect on the depth of ink penetration into the printing substrate, so that cereal straw can be used as waste material for the production of secondary packaging. In general, prints with gravure inks have lower ink penetration compared to offset inks.