DEVELOPMENT STORY
August 23, 2024
The Development Story of FRIXION, the Erasable Ballpoint Pen: Part 1: The Discovery of Thermo-sensitive Ink, 1970 to 2002
The FRIXION series, which was first launched in Europe in 2006, is now sold in over 100 countries and regions around the world, with more than 4.4 billion units sold by the end of 2023. Having continued to release new items in the series since its launch, we introduced the new category of erasable pens in the writing instrument market.
The FRIXION series took around 30 years to develop before launch, with more than half a century of continuous research and development combined, continuing even after its launch. In Part 1, we will tell you about the story of development leading up to sales and why it took over 30 years to launch the series.
The selling point of the FRIXION series is the special ink used, which changes color with heat. The concept for this ink came about more than 50 years ago in the autumn of 1970, when a PILOT researcher was inspired by a natural phenomenon.
This researcher, who had continuously been on the lookout for the development of new ink, was inspired by the majestic sight of the autumn leaves on a mountain. “The change in color of the autumn leaves happens overnight, and I want to create the same color transition in a test tube.” This is where his research into color-changing ink began.
In those days, ink was meant to remain unchanged semipermanently, even if subjected to light or heat. This idea of color-changing ink shattered the status quo of ink at the time. There were no past experimental results or scientific materials to draw hints from. Heat, humidity, UV rays, light, or otherwise - the research continued as the researcher sought to determine what causes ink to change colors. After a year or so had passed since the idea first came, this researcher discovered a fundamental concept. From this concept was born the world's first ink that could change colors from changes in heat.
He applied for a patent for this ink that had hidden its possibilities the following year, in 1972. This ink was named Metamo Color from the word “metamorphose,” meaning to change or transform.
After gaining the patent in 1975, we launched the Magic Cup in 1976, the world’s first paper cup using Metamo Color, which changed color when cold water was added.
It was around this time that PILOT began working to open up markets with Metamo Color as an ink for printing, while steadily conducting fundamental research by combining various materials in hopes of improving performance. And through joint research with other companies, we were able to further refine this technology.
And ten years later, in 1985, PILOT launched its first toy, the Mellchan Magic Shrimp Fryer. And so, PILOT was able to enter the toy market with this clever toy, making use of color changes from heat. Metamo Color had taken a big first step into a new market.
At the time, however, no one had yet thought of using this ink in writing instruments. After all, the prevailing belief was that ink in pens should never change color, even after years, so no one had made the connection between pens and the idea of color-changing ink.
Products that used Metamo Color generated publicity, but there were still two challenges remaining that needed to be solved for further development. The first was the challenge of establishing an exact temperature at which the color would change. At the time, Metamo Color would gradually change color as the temperature rose, but would naturally return to its original color if left to cool, and there wasn’t a clearly defined boundary between color changes. To refine the temperature at which the color would change, research was focused on one of the elements within the microcapsules that control the colors: the discoloration temperature regulator (see graphs below).
What was first developed was a highly sensitive ink that would instantly change color at a certain temperature and would immediately return to its original color if its temperature dropped. This highly temperature-sensitive ink was used to display the ideal drinking temperature of beer and wine.
The next challenge was to create a memory-type ink that would maintain its color change. The goal was to expand the range of discoloration temperatures between when the color changed and when it returned to its original color. For example, let’s say applying heat to red ink causes it to turn yellow at a certain temperature. With the original Metamo Color, this ink would gradually turn back into red, but with the memory-type ink, it would require the ink to cool to a certain temperature to change back to red. In other words, this ink would retain its yellow color until it reached a determined cooler temperature.
Through repeated experiments with the special discoloration temperature regulator, in 1988, the development of a memory-type ink was successful, producing an ink that would maintain its changed color within a temperature range of approximately 20°C.
With the development of this memory-type ink, the potential for Metamo Color development greatly expanded. By responding to the needs of companies in Japan and abroad through the provision of this technology, PILOT’s technological capabilities were further enhanced. The Makeup Doll, born from joint development with a U.S. toy manufacturer, was a particularly big hit. This generated a lot of publicity. Then, in 1992, PILOT launched Bath-Loving Mellchan, a doll whose hair changes color in the bath. This doll became popular among Japanese children and has continued to be a beloved long-selling product for over 30 years.
By the 1990s, this temperature-based color-changing technology had spread throughout the market through technical collaborations with many companies. This led to a variety of products, including toy trains that changed color in the bath, temperature indicators for in-flight meals, and counterfeit-proof tickets. As products were commercialized in a range of fields, Metamo Color became a business of its own.
The second challenge was in miniaturizing the microcapsules in the ink.
Up until the 2000s, Metamo Color was not considered for use in writing instruments, despite having been applied to many different products. This was because the microcapsules used in the ink were too large. To use this ink in a ballpoint pen, it would require shrinking these microcapsules so that they would smoothly flow out of the extremely small gap at the tip of the pen.
Metamo Color ink is composed of three components (the color-producing agent, the color-developing component, and the discoloration temperature regulator) contained within very small microcapsules. Particles in conventional ballpoint pen ink are around 0.1 to 1 micron in diameter, but when first developed, the particles of Metamo Color ink were between 10 and 15 microns, which was an extremely large size that could not be used as ink for writing instruments. When the memory-type ink was developed, the particles had been reduced to between 5 and 10 microns, but this was still too large for pens. As the smaller capsules had thinner membranes, they were easy to burst, and it became difficult to develop a more durable membrane.
By 2001, the Metamo Color microcapsules had been reduced to between 2 and 3 microns, enabling their use as an ink for ballpoint pens. Compared to a single human hair with a diameter of between 80 and 100 microns, these capsules were just 1/40 of that size at 2 to 3 microns. You can see from this comparison the microscopic level at which these experiments were conducted. These miniaturized Metamo Color microcapsules were developed to be of a size that would smoothly pass through the tip of a ballpoint pen.
But there was still one hurdle left to overcome. At this point, the discoloration temperature range had been expanded to 40℃ (between 0 and 40℃), but with the Japanese climate having some summer days exceeding 40℃ and winter days dropping below freezing, the temperature of the ink could easily exceed this temperature range. If the ink’s color could change based on temperature changes, then it wouldn’t be considered practical for use in writing instruments. Even so, work towards developing a ballpoint pen using the miniaturized Metamo Color began.
So in 2002, PILOT launched the curious ILLUSION series of ballpoint pens. Rubbing the ink with the rubber part of the pen cap would cause the ink to change colors. This was the first writing instrument to use Metamo Color technology. When writing, the color was black, but after rubbing the ink, it would change color due to the heat from friction. These decorative pens were an experimental release.
A remark made by a marketing person at PILOT’s European subsidiary, who had seen the ILLUSION pens for himself, launched the movement to commercialize erasable ballpoint pens using Metamo Color that could be erased through frictional heat.
〉〉〉The Commercialization of the FRIXION Erasable Ballpoint Pen (Continued in Part 2)
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