Effect of acidity and alkalinity of printing paper on ink discoloration
In general, paper is weakly alkaline. The ideal paper has a pH of 7 and is neutral. Because of the need to add caustic soda (NaOH), sulfide, chlorine and other chemicals during the papermaking process, improper handling in the pulping and papermaking process may result in paper. It is acidic or alkaline.
The acidity and alkalinity of the paper has a great influence on the color durability of the printing process and the printed matter. The acidity and alkalinity of the paper has a direct effect on the drying of the oxidized conjunctiva of the imprint, and the drying of the acid-stained paper is particularly slow because the acidic substance inhibits the drying of the imprinted oxidized conjunctiva.
The acidity and alkalinity of the paper can also cause discoloration and discoloration of the ink. The raw material paper PH value is less than 7 is acidic, more than 7 is alkaline, the acidity of the paper and the water hopper solution is also weakly acidic and other factors, it will affect the ink, causing it to change color, such as peacock blue after the acid turns green .
Oil smog has poorer alkali resistance. Basically all inks will fade or discolor when exposed to alkali. The chrome yellow ink turns red when it is alkali, and the medium blue fades when it is alkaline. In particular, gold ink, silver ink, and electro-chemical aluminum foil bronzing will lose their original luster when exposed to alkaline substances. The golden color will turn into an ancient yellow color, the silver will become black and not bright, and the adhesion will decrease, which will often cause the printed matter to be scrapped.
The acidity and alkalinity of the paper has a great influence on the color durability of the printing process and the printed matter. The acidity and alkalinity of the paper has a direct effect on the drying of the oxidized conjunctiva of the imprint, and the drying of the acid-stained paper is particularly slow because the acidic substance inhibits the drying of the imprinted oxidized conjunctiva.
The acidity and alkalinity of the paper can also cause discoloration and discoloration of the ink. The raw material paper PH value is less than 7 is acidic, more than 7 is alkaline, the acidity of the paper and the water hopper solution is also weakly acidic and other factors, it will affect the ink, causing it to change color, such as peacock blue after the acid turns green .
Oil smog has poorer alkali resistance. Basically all inks will fade or discolor when exposed to alkali. The chrome yellow ink turns red when it is alkali, and the medium blue fades when it is alkaline. In particular, gold ink, silver ink, and electro-chemical aluminum foil bronzing will lose their original luster when exposed to alkaline substances. The golden color will turn into an ancient yellow color, the silver will become black and not bright, and the adhesion will decrease, which will often cause the printed matter to be scrapped.
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