1, space pen
Space pen, that is, pressurized ballpoint pen, is a novel technology. Take Fisher Space Pen as an example. The refill of the space pen is pressurized (~0.28MPa), and its ink is a special viscous ink (like sticky rubber glue). In order to turn viscous ink into liquid, the ball must rotate, so that the ballpoint pen can write smoothly on the surface of most objects or even underwater. Ordinary ballpoint pens supply ink by gravity, and there is an opening above the refill so that air can replace used ink. The space pen has no small holes, which avoids the evaporation waste of ink and the leakage of ink from the back of the refill. In addition, the service life of space pens can be as long as 100 years, while the average storage life of ordinary ballpoint pens is only two years.
Since the beginning of the "Space Race" in 1960s, American astronauts have used space pens in all manned space flights, including the moon landing project. In addition, they are also used by many Russian astronauts in Soyuz space flight and Mir space station.
2, erasable ballpoint pen
Erasable ballpoint pens were introduced in the early 1980s and were all the rage at first. They combine the readability of bright or black ink with the erasable function of pencils. Although these ballpoint pens are still produced under the banner of brands such as Gillette eraser Mate, they are not as popular as before. Patent documents such as US29664 18 and US4097290 describe these ballpoint pens in detail.
Erasable ballpoint pen is unique in its "ink"-it is made of liquid rubber glue instead of oil and dye. When you write, the beads roll and release the rubber glue ink on the paper (the resulting traces are called tracks). Modern erasable ballpoint pen will leave clear and heavy black or color marks on paper, which looks similar to ordinary ink, but it can be easily erased soon after writing (usually as long as 10 hour). After this time, the marks will harden and become indelible.
The ink of erasable ballpoint pen generally contains 15% ~ 45% by weight of natural rubber, which is dissolved in a series of volatile organic solvents with different boiling points.