If I accidentally eat the "oil" from a gel pen, is it okay?

Review expert: Gan Qiang, lecturer at Beijing Institute of Technology, PhD in Applied Chemistry

I don’t know if you have noticed that there is always a piece of colorless or yellow mysterious liquid at the end of the gel pen refill. When I was a kid, when I was bored in class, I would always try to poke the refill of a mechanical pencil in to stir it, or pull out the front end of the refill that was almost used up, then hold the end of the refill in my mouth and blow it out, or suck it into my mouth... Of course, the result was either being caught by the teacher for being absent-minded, or accidentally smearing the ink in the refill everywhere, making it dirty.

The above scene may be a common memory of many friends in their childhood. So, what are these mysterious liquids? Why don't these liquids flow back down the pen tube? Why is it always sticky? Curiosity comes from confusion. Today, let's solve this problem left over from childhood!

Source | Baidu Encyclopedia

1

Follow-up sealant

What is the liquid behind the gel pen ink called? In fact, it does not have a unified name. Everyone likes to call it according to their own understanding and knowledge of it. In terms of function, some people call it "follow-up sealant"; in terms of the material, some people call it "lithium ester"; because it is located at the end of the pen core, some people call it "tail plug oil" .
Although it is only a short piece, it actually has a great effect.

First of all, it has good moisture retention and sealing properties . The ink in the refill is generally a low-viscosity liquid containing dyes, which is easy to evaporate in a dry environment, causing the ink to thicken or dry up and unable to write normally. In addition, due to the low viscosity of the ink itself, it is very likely to flow back in the ink tube.

However, these two problems can be well solved by "follow-up sealant". No matter what kind of environment the refill is placed in, no matter whether the refill is placed upright or upside down, there will be no problem of ink evaporation or leakage, and it will not flow back through the ink tube. This is why some people call it a "sealant".

Source | Baidu Encyclopedia

In addition, the sealant can make the writing process smoother . During use, the sealant can flow forward like a "piston" as the ink decreases. Under the action of atmospheric pressure, it can press the ink down with a relatively stable force, so that the writing can be smooth and the ink can be stable.

All in all, the design of the follow-up sealant is very clever.

Friends who are usually more careful may ask, why is there no follow-up sealant in ballpoint pens? To be honest, I was also confused by this question. In fact, this is determined by the characteristics of the ink itself. Compared with neutral pen ink, ballpoint pen ink is not easy to evaporate and dry ; at the same time, because its viscosity is much higher , we don’t need to worry about the problem of ink flowing back along the ballpoint pen barrel. This is why ballpoint pens do not need to add follow-up sealants.

2

Why is the gel pen called "neutral"?

The dictionary definition of "neutral" is between two relative properties. The so-called "neutral" of gel pens is relative to fountain pens and ballpoint pens . Fountain pens are also called fountain pens because their ink is made from tap water and water-soluble toner. This type of ink has a very low viscosity and is easy to evaporate. The liquid in the refill of a ballpoint pen is oily, and its viscosity is very high and not easy to evaporate. The viscosity of the ink of a gel pen is between water-based and oily, and it is in a gel state, containing organic solvents such as alcohols and organic ethers.

Source | Baidu Encyclopedia

The gel pen originated in Japan and is currently a very popular writing tool in the world. The gel pen has the advantages of both fountain pens and ballpoint pens. It has a comfortable writing feel and low ink viscosity. The added lubricating substance makes the writing process smoother than that of oil-based ballpoint pens. Therefore, the gel pen has also become an upgraded product of oil-based ballpoint pens.

3

What are the nib structures of gel pens?

The nib structure of a gel pen can generally be divided into three types: bullet tip, full needle tube, and half needle tube (gourd head).

Source | A social media

Bullet nibs, as the name suggests, have a bullet-shaped nib structure. The manufacturing process is to cut a raw rod into a complete nib through metal cutting. The nib made by this manufacturing method is thicker, generally around 0.5mm , and the thickest can even reach 1.2mm.

Unlike the bullet-shaped pen, the full-tube pen core is made by non-cutting method. This manufacturing method produces a thinner pen tip, such as 0.30mm, 0.25mm , etc.

The gourd-shaped refill is between the bullet-shaped and full-needle-shaped. The tip of the gourd-shaped refill can be as thin as a needle, while the end of the pen tip is as large as the end of the bullet-shaped refill. The gourd-shaped refill is generally available in 0.35mm and 0.48mm .

4

What should I do if I accidentally swallow it?

This question is actually very interesting. In fact, when I was a kid, I sucked the ink and sealant from the pen tube into my mouth because I was naughty, but I quickly ran to wash it off. Now, I only vaguely remember that I was teased by my classmates for a long time.

If you really taste the sealant by accident, don't worry too much. Just spit out the ink in your mouth quickly, rinse your mouth in time, drink plenty of water, and promote excretion, there will be no harm .

However, there are exceptions to everything. If you have a headache, fever, or stomachache after accidentally ingesting the ink in the ink cartridge, you should go to the hospital in time to avoid uncontrollable symptoms. Therefore, naughty children, you should be careful not to try it. After all, the original function of a gel pen is to write well.