Ink

The twin pen and ink tools have been used since around 2500 BC. C. Used when Chinese and Egyptian societies independently developed writing ink. Today, as then, ink for pens is made according to a similar recipe: a strongly colored substance is suspended with stabilizers in a liquid that a pen can slide over the paper. Since then, innovations in chemistry have varied the chemical composition of the ink.

Fountain pens that preceded ballpoint pens used fine water-based ink and hung from gravity to draw the ink to the tip of the pencil. They had to be held at certain angles and used with caution; otherwise, the mechanisms will break or the ink will stain.

 

The development of the rough ball in the early 1940s by the Hungarian brothers Lasdislas and Georg Biro (whose names are still on some Bic pens) solved the problem of gravity in combination with thick oil-based newspaper ink. . It wasn't until 1949 that Fran Seech developed the modern formula for pen ink that made Paper Mate pens so popular. It took more than paint and solvent.

Colorants:

The color of ink comes from a dye that can be dissolved in water or from a pigment that is insoluble in water. The Eosin Y dye gives red ink its color and is made by adding the element bromine to a fluorescent compound. Inks that use pigments include white ink (which contains titanium oxide) and metallic gold ink (which, surprisingly, uses a copper-zinc alloy). Soot, a pigment made from carbon and oil, is an integral part of black pen ink.

The ink in a normal pen consists of dye or pigment particles: Carbon for black pens, eosin for red or a suspected cocktail of Prussian blue, crystal violet, and phthalocyanine blue for the classic blue pen.

Solvents:

The earliest forms of writing ink consisted of stabilizers that contained fuel residues, perhaps the most abundant liquid solvent on the planet: water. Centuries later, manufacturers began to use chemicals other than solvents. Petrochemicals, which are mainly made up of carbon and hydrogen, continue to be used in ballpoint inks.

Markers use ink made with alcohol as the solvent. However, recent restrictions on the use of carbon-based compounds in the industry have led manufacturers to revert to the idea of ​​water-based inks.

Colorant suspended in an oil or water solvent. The most common oils are benzyl alcohol or phenoxyethanol, which are mixed with pigments or dyes to create a smooth, vibrant ink that dries quickly. However, ink is more than its two main components. The pen works with pigment and solvent only but might need some improvement.

Stabilizers:

Inks can coagulate when their dye or pigment particles clump together. Stabilizers prevent clotting by sticking to molecules and moving them over each other, giving the ink a smoother flow. Polymers, large molecules made up of chains of repeating units, are excellent stabilizers. 

In the past, plant resin and egg albumin served as sources of stabilizing polymers. Laboratory creations such as polyvinyl chloride and polyvinyl acetate fulfilled this role in the late 20th century.

Research has also suggested other additives that can improve the basic properties of the ink. Glycerides, which contain fatty acids and glycerin alcohol, can be extracted from plants and added to facilitate the glide of the ink on the paper. Chemicals that regulate the pH of the ink, such as triethanolamine, prevent the ink from becoming acidic or corrosive enough to damage the pens.

Election ink:

The silver nitrate is used in election ink. Ink dries in less than 40 seconds and leaves a dark stain. However, the strength of the stain depends on the amount of silver nitrate used. According to the manufacturers, the concentration of silver nitrate is between 7% and 25%, but the exact composition cannot be revealed due to property problems.

The ink stays on the skin for at least 72 hours. Silver nitrate is preferred because it is soluble in water and gives an ink-black solution. When applied to the skin, silver nitrate reacts with salt to form silver chloride. Silver chloride is not soluble in water and adheres to the skin. It cannot be washed with soap and water. It can't even be washed with hot water, alcohol, nail polish remover, or bleach. The ink will disappear as the old skin cells die.

Mysore Paints and Varnish Limited is a company based in the city of Mysore, India. It is the only company in India authorized to manufacture indelible ink that is used in elections to prevent people from voting multiple times. 

To remove the stain pour excess household ammonia on the stained areas of ​​the skin. Rub the area firmly with a cloth to remove the silver chloride stain. Silver chloride reacts with ammonium hydroxide and is poorly soluble in ammonia, but according to Le Chatelier's principle, it dissolves in an excess of concentrated ammonia solution. If it did not vanish then use concentrated acids like nitric acid, sulfuric acid, and hydrochloric acid. 

Reference:

1) https://en.wikipedia.org/wiki/Ink

2) https://www.pcimag.com/articles/85040-pigments-in-ink

3) https://www.chemistryworld.com/news/ink-chemistry/3002158.article

4) https://en.wikipedia.org/wiki/Election_ink

5) https://youtu.be/Fypi6dAJB8E