~ to dry, to harden ~
Ink is required for screen printing. And the use of ink always involves the process of drying the ink. This time, let's consider the drying of this ink from a familiar phenomenon.
So what is the boiling point of water? Of course, I think everyone is well aware of 100°C. When you put water in a pot and heat it on the stove, the temperature of the water eventually reaches 100°C and boils, and the water gradually evaporates and decreases. Does water evaporate only at 100°C? Here, remember to wash your clothes every day. Do you dry your laundry at 100°C? If you dry your clothes at 100°C, they may be damaged. Even if you dry your laundry outside, it will dry well. But on rainy and damp days, it's hard to dry the laundry. In addition, laundry on dry days dries quickly.
On a different note, instant adhesives are often used as stationery. It's very comfortable and sets up quickly. Even though it is an adhesive that hardens quickly, why doesn't it harden when sold at a store? That's strange. In fact, this adhesive hardens by reacting with moisture contained in the air. Therefore, if you put it in a container that does not allow water to pass through, it will not harden.
The same is true for the inks used for screen printing. There are various drying and curing methods for inks used in screen printing. Therefore, it is necessary to understand the contents of the ink well and determine the drying conditions. Ink characteristics and drying are explained below.
・Evaporative dry ink
The temperature is irrelevant, as the solvent contained in the ink should evaporate.Just dry it like laundry. For example, far-infrared rays are used for efficient drying. Since far-infrared rays are a type of electromagnetic wave, they are absorbed by polymer materials and heat them from the inside. When you hit an infrared stove in winter, your body gets hot even if the air around you is cold. It's the same principle. For materials that are sensitive to heat, cooling with air while heating with far infrared rays can dry the ink without damaging the material.
The temperature is irrelevant, as the solvent contained in the ink should evaporate.Just dry it like laundry. For example, far-infrared rays are used for efficient drying. Since far-infrared rays are a type of electromagnetic wave, they are absorbed by polymer materials and heat them from the inside. When you hit an infrared stove in winter, your body gets hot even if the air around you is cold. It's the same principle. For materials that are sensitive to heat, cooling with air while heating with far infrared rays can dry the ink without damaging the material.
・Curable ink
Various conditions are required to cure the ink because the curing agent contained in the ink chemically reacts. For example, inks that contain components that react with water, such as instant adhesives, will not harden even if heated for a long time unless water is present. In the case of ink that cures only at a certain temperature or higher, even if it is heated at a low temperature, only the solvent contained in the ink evaporates and does not cure, so sufficient characteristics cannot be obtained. Also, for ink that takes 10 minutes to complete the curing reaction, at least this time is required.
Various conditions are required to cure the ink because the curing agent contained in the ink chemically reacts. For example, inks that contain components that react with water, such as instant adhesives, will not harden even if heated for a long time unless water is present. In the case of ink that cures only at a certain temperature or higher, even if it is heated at a low temperature, only the solvent contained in the ink evaporates and does not cure, so sufficient characteristics cannot be obtained. Also, for ink that takes 10 minutes to complete the curing reaction, at least this time is required.
・The drying oven should match the ink.
It is often written in the catalog of the drying oven manufacturer that "it can be dried at high speed". Depending on the ink, it certainly dries faster, so it's not wrong. But is the ink you're using "evaporative drying"? Is it "curing type"? This will change the structure of the drying oven. It is important to select a drying oven with a good understanding of ink drying and curing mechanisms.
It is often written in the catalog of the drying oven manufacturer that "it can be dried at high speed". Depending on the ink, it certainly dries faster, so it's not wrong. But is the ink you're using "evaporative drying"? Is it "curing type"? This will change the structure of the drying oven. It is important to select a drying oven with a good understanding of ink drying and curing mechanisms.
