(1) blue and black ink
Also known as iron tannate ink, it consists of blackening component, pigment component, stabilizer, corrosion inhibitor, wetting agent and preservative.
1. Black persistent ingredient:
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 (HSO4), 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.
6. Preservatives:
Organic substances and other substances contained in ink raw materials are easy to rot and mold in humid environment. In order to prevent decay, chemicals such as phenol or sodium pentachlorophenol are often added as preservatives.
(2) Pure blue ink and red ink
Pure blue ink and red ink are organic dye inks. Although their colors are bright, their handwriting is not as strong as blue and black ink, and it is easy to fade. However, red ink will fade and penetrate quickly when it meets water, so pay special attention to it.
(3) Carbon ink
Its composition is mainly inorganic carbon, which is naturally stable.
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