For achieving optimum flexo printing quality, there are major steps that should be followed. PH CONTROL: Proper pH is critical to achieving sharp and defined printing image. Ph that is not properly adjusting from color to color on the printing machine will cause a number of printing defects. pH is acidity, neutrality or alkalinity of a liquid ranging from 1 to 14 on a pH meter. Below 7 is acid and above 7 is alkaline and 7 is neutral. Flexographic ink should be on the alkaline side of the scale, so pH should never be below 8 or higher than 9.5 in flexo ink pH reading should be taken and adjustment made when viscosity readings and adjustment are made. pH adjuster, supplied by the same ink supplier. The challenge is in keeping pH up, not down, and to achieve the stepping of pH, it is important to use measuring cup amounts for this purpose, hot humid condition and evaporation accelerate downward movement in pH. VISCOSITY CONTROL: Ink viscosity determines the rate of flow and is measured in seconds by using a No.2 Zahn cup, the device that allows liquid to through an opening at the bottom of the cup, and which is the adopted instrument of the corrugated board industry. The proper viscosity is that which achieve suitable coverage and color density matching a costumer color sample. Two vehicles are used to reduce the viscosity, water, and extender varnish. As with pH adjuster, a measuring cup of either water to extender varnish should be used to avoid reducing viscosity to a point where desire coverage and density are no longer achieved. Often it is better to use extender varnish that has the same properties as ink, except pigment. This vehicle will have less effect in reducing the solid content of the ink. In the next article, we will talk about setting impression and cleaning printing plate.
Printing Ink Raw Materials Resins These are commonly referred to as binders or carriers. Their prime function is to carry the pigment to the substrate and anchor it there. The choice of binder can also impart physical properties to the final ink film e.g. hardness, gloss, water resistance, chemical resistance, resins are normally either dissolved in or dispersed in a solvent to give a fluid product. This fluid product is usually referred to as a varnish. Pigments these are the colorant of the ink and are chosen to give the correct color (or hue). Pigments are primarily insoluble and need to be dispersed into the carrying medium (varnish). Pigments impart a large number of physical properties to the finished ink film. These properties are typically light fastness, water resistance, soap resistance, butter resistance, wax resistance. Generally speaking the greater the resistance of the pigment the more expensive the pigment is. Dyes – Dyes are different to pigments in that they are soluble in a solvent (usually alcohol or water). Dyes have high color brilliance and strength but lack fastness properties. Dyes usually high poor lightfastness. Some dyes can be lacked to form a type of pigment. This process enhances the fastness properties of the dyes. Solvents are used to dissolve resins to form varnishes. Solvents can be chosen to alter the drying speed of an ink but must be accurately balanced to provide a stable ink formulation. Common solvents are alcohols, esters, ketones. Some solvents are flammable so their use needs to be well controlled in ventilated flameproof environments. Water is also a solvent. Most resins are soluble in a range of solvents. Slip agents are used to imparting slip and scuff resistance to an ink film. Differing printing and production process require differing levels of slip from the ink.e.g a form fill & seal machine must use an ink with highest slip level so the forming bag can slide over turning bars easily. A tray for cans of drinks must have a low slip ink so that pallets loaded with goods don’t slide out of control. The ink maker can tailor make an ink to have the required slip level for the end use of the product concerned. Additives – includes antifoams, surfactants, viscosity modifiers and other ink components. These additives can be essential to some formulations but are only added where a particular property is required. The quantities of additives usually found in an ink formulation are usually 0 – 5 %.
Selling flexo water-based ink By ECAT expertise Flexo Water-based ink is one of the types of printing ink which uses in carton Boxes printing and cement sacks which is means, the users of flexo water-based ink are the organizations in another meaning, selling flexo water-based ink is B2B type, so selling product like flexo water-based ink becomes not easy because you are dealing with organizations has policy in purchasing. Flexo Water-based ink has some physical and chemical properties should the seller of know it well to be able to present his product to the customer in proficiently way specially the buyer has good knowledge about what he purchases, also there are many applications of water-based ink in another meaning a lot of users of flexo water-based ink like corrugated carton printers, cement sacks manufacturers, tissue paper manufacturers,…. knowing the characteristics Seller of flexo water-based ink as we mentioned should know more about characteristics of flexo water-based ink especially physical properties which act the main factors during printing like viscosity, color strength, specific gravity and so on, Because of the users of flexo water-based ink want to discuss all these details and features with the seller that’s why should his ability to discuss this technical information so, nowadays most of the water-based producers insist to train selling staff technically to able to talk not only talk but solve problems sometimes which face the users of water-based flexo ink . On another hand, the seller of flexo water-based ink should have talent and should attend some training to improve his ability to present and improve his skills in selling. Collecting data about flexo water-based ink users become very easy by using internet, social media, associations, trading and industrial chambers.