In general, the paper is to present a weak alkaline. PH value of 7, the ideal paper neutral, because in the process of paper making, need to add the caustic soda (NaOH), sulfur, chlorine and other chemicals that, in the process of pulping and papermaking process inappropriate and could make the paper acidic or alkaline. Paper acid alkali for printing process and has great effect on the color of the print durability. Paper acid alkaline oxidation conjunctival dry has a direct effect of imprinting, acidic paper imprinted drying is particularly slow, this is because the acidic substances inhibit the conjunctival dry oxidation of imprinting.
Paper acid alkali can also cause ink fading and discoloration. Raw materials paper 7 acidic PH value is less than, greater than 7 alkaline and acidic strong paper and due to factors such as basin also has weak acid solution, will affect the ink, the color, such as the peacock blue green after acid.
Less oil halo alkalis. Basically all ink in alkali fading or discoloration. Encounter alkali become red, chrome yellow ink in blue in the alkaline paper fade. Especially gold ink, silver ink, electrochemical aluminum foil hot stamping in alkaline substances will lose their original luster, brassy colors into the ancient yellow, bright silver, black, and adhesion, tend to cause scrap print.
(Gold Printing Group) |
