Ink is a liquid containing pigments or dyes. Ink is used for writing or painting. The earliest inks were dyes made of metal, walnut shells or seeds, or inks made of aquatic animals such as fish and octopus. China ink is carbon ink.
Ink:
Iron tannin ink consists of blackening component, pigment component, stabilizer, corrosion inhibitor, wetting agent and preservative.
1, blackening persistent component:
Mainly tannic acid (C4H 10O9) and gallic acid (C7H6O5? H2O) and ferrous sulfate (FeSO4) combine with each other to form ferrous tannic acid and ferrous gallate, which are insoluble high-valent iron after oxidation, namely ferric tannic acid and ferric gallate. The former enhances water resistance, while the latter enhances blackening, thus making the ink water-resistant, blackening and durable.
2. Pigment composition:
At present, acid ink blue and direct lake blue dyes are commonly used. Black water blue is the main color of ink, and the aqueous solution does not deteriorate in acid, but turns brown in alkali. Direct lake blue plays an auxiliary role in ink, because it contains more impurities, so it is not suitable for multi-use, and it is easy to grow mildew in wet environment.
3. Stabilizer:
The main purpose of adding stabilizer to ink is to eliminate the precipitation of ink and avoid the phenomenon of water shortage when writing. Commonly used stabilizers are sulfuric acid (H2SO4), oxalic acid (COOH)2 and formaldehyde (HCHO) solution. These stabilizers have certain acidity, which lays a hidden danger for paper acidification and should not be used more.
4. boycott:
Because the stabilizer added in ink has strong acidity, in order to prevent corrosion, a corrosion inhibitor is often added to form a film with iron to reduce the corrosion effect of sulfuric acid by 90%. The iron content in the ink will not increase due to the corrosion of the pen tip, thus increasing the stability of the ink.
5. Wetting agent:
In order to prevent the water in the ink from evaporating, which makes writing inconvenient, glycerol [C3H5 (OH) 3] which is non-volatile and absorbent is added to the ink to keep the nib moist and facilitate writing.