Ink is an indispensable material for the decoration and packaging of printed goods. Through printing, the packaging surface becomes beautiful, colorful, and attractive. With the rapid development of the printing industry in recent years, the packaging and printing of various plastics and paper industries have continuously improved, and the requirements for product packaging have become higher and higher. Composite flexible packaging printing is different from general packaging printing, that is, the former is lining printing, and the latter is surface printing. The inks used in the two are called lining ink and surface printing ink. We must analyze the differences between these two inks before printing and use them correctly.
The difference between binders
The binder of surface printing ink is mainly polyamide resin, which has good adhesion and good gloss, but it is not suitable for high-temperature conditions and has poor fastness when laminating. The binder of non-cooked lining ink is mainly chlorinated polypropylene. Nitrate fiber and vinyl chloride-vinyl acetate copolymer resin are also used abroad.
The difference between the solvents used
The solvents used in surface printing inks are mainly xylene and isopropanol. In general, toluene and ethyl acetate are the main solvents for lining printing inks. The high-temperature cooking lining ink is mainly ethyl ketone and ethyl acetate. The lining ink solvent is suitable for high-speed printing, the volatility of the solvent is fast, and the solvent residue is particularly small.
The difference in wear resistance
Because polyamide resin has good softness and greater elasticity, the added additives make it better and improve its abrasion resistance, and it is firmer in contact with external objects. The lining ink resin chlorinated polypropylene resin has particularly good rigidity and poor abrasion resistance. Because it is a lining printing, the requirements for abrasion resistance are correspondingly lower.
The difference between auxiliary materials and additives
Due to the different binders, the auxiliary materials and additives of surface printing inks and lining printing inks are also different. Surface printing inks often add dehydrated apple and kiwi fruit acid esters to improve adhesion, gloss, and viscosity. In printing ink, various pigment dispersants, enhancers, defoamers, and other additives are added.
The difference in the printing process
The lining printing plate-making process is the same as the general plate-making process, but the image on the printing plate is the reverse image when the surface printing plate is made, and the image on the printing plate is the positive image after printing. The printing speed of surface printing ink is slow, and the printing speed of lining printing ink is faster than that of surface printing.
As a professional factory over 20 years in the field of food packaging, kolysen Packaging has developed various composite flexible packaging products such as laminated film roll, standup pouch, coffee bag, aluminum foil pouch, retort pouch, spout pouch, welcome to contact us if any question or interested on our products.
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