Lithographic printing ink is offset printing ink, is suitable for a lithographic printing ink. Lithographic printing layout of each part basically in a plane, picture and text of the lipophilic, non graphics and text is hydrophilic, printing by using the principle of water and oil repellent, so lithographic printing ink must have water resistance. Lithographic printing ink according to the process of points can be divided into offset printing ink, drum
offset printing ink, leaflets offset printing ink, anhydrous offset ink, printing ink, lithographic ink, collotype printing ink.
Lithographic printing ink repellent principle based and lithographic printing ink in printing will frequent contact with water. Therefore, it is necessary to have strong water resistance, prevent ink emulsification.
Offset printing ink is generally through the rubber roller transfer printing, printing to paper printing ink film are relatively thin, thus requiring ink pigment ratio should be higher, pigmenting stronger. The pigment, not only requires the hue to meet the printing, coloring is stronger; at the same time the paint fast, acid and alkali resistance, resistance to chemical solvents etc. requirements are very strict; due to the dispersion of pigment made of ink liquidity is poor, poor tinting strength, so lithographic ink pigment dispersion will make other requirements.
Lithographic printing ink includes all offset printing ink, lithographic printing inks, lithographic photosensitive printing inks, collotype printing ink, offset thermosetting ink.
In offset printing ink formulation design principle, we must first considering lithographic printing ink in the printing process will frequent contact with water, offset printing ink to has strong resistance to water, to prevent over lithographic ink emulsification. This requires the lithographic printing ink pigment must be strong water resistance of pigment is insoluble in water and solvent, otherwise in the printing process pigments can in under the action of mechanical friction from binders, soluble in fountain solution, leads to the non printing graphics and text portion of the coloring, affecting the quality of; because it is indirect printing, transfer ink layer is thin. Therefore, pigmenting stronger, lithographic printing ink pigment in the proportion of the appropriate higher.
Pigment dispersion also requires, in order to ensure the liquidity of lithographic ink. Binders are the heart of the ink, especially for lithographic ink. If binders water resistance is not good, will produce serious emulsification, causing the ink delivery, will also influence lithographic printing ink drying performance; in addition, binders of color, viscosity, pH value will bring about obvious influence properties of offset printing ink. Generally speaking, the greater the molecular weight of the link, the better the water resistance, the use of oil based links in the past to the main oil based, its poor water resistance, slow drying, has been rarely used. Lithographic printing ink now used all kinds of resin binders.
Offset printing ink in various printing, offset printing ink in China occupies volume of close to 50%, still occupies a dominant position, in the next 20 years will still be steady development. Lithographic printing ink production enterprises and service enterprises, in order to develop, only to provide a full range of services. Price competition is clearly not a way, must become a comprehensive printing service provider.
In a word, the lithographic printing ink industry development faster, but to and the international community will have to increase investment, improve the level of large-scale production, bigger, stronger enterprises, and comprehensively improve the level of product quality, to develop non-toxic harmless, as soon as possible to narrow the gap with foreign offset oil ink meet the needs of domestic and international market.
