～Like a mandarin duck couple～
Couples who are always together and get along well are called "Oshidori Fufu".
The word comes from the fact that a couple of mandarin ducks always snuggle up to each other. However, when they are always together, after mating, the female lays eggs and keeps them warm until the chicks hatch. When the chicks hatch, the male leaves. They live in groups with other males and find new females each year. It doesn't mean that you can't change your partner for the rest of your life.
The word comes from the fact that a couple of mandarin ducks always snuggle up to each other. However, when they are always together, after mating, the female lays eggs and keeps them warm until the chicks hatch. When the chicks hatch, the male leaves. They live in groups with other males and find new females each year. It doesn't mean that you can't change your partner for the rest of your life.
What does this have to do with screen printing?
The squeegee used for screen printing is also compatible with the ink solvent.
If the squeegee and the ink solvent are on good terms like the mandarin duck couple, they will snuggle up to each other and eventually melt into each other. When this happens, the squeegee becomes happy and fat, and it's no longer about printing. It is very difficult to separate the squeegee and the solvent, and no matter what you do, they will not be restored.
So what if the squeegee and the solvent don't get along?
Even in the case of humans, people who are not compatible with each other don't talk to each other, and they probably don't want to hold hands with each other.
It may be like a mandarin duck after a chick hatches. The squeegee and solvent are not compatible with each other. In this case the squeegee does not change anything.
How could this happen? Substances have the property that substances with similar structures tend to mix.
For example, water and alcohol mix because they have similar structures. This is why whiskey is diluted with water.
Also, water and oil do not mix because their structures are not similar. This is the reason why dressings containing salad oil separate immediately even if they are shaken vigorously.
Most of the solvents commonly used in screen printing have a different structure from urethane rubber, so if you print with a urethane rubber squeegee, the squeegee will hardly change. However, NMP and DMF solvents have structures similar to those of urethane rubber. Therefore, if you use a urethane rubber squeegee when printing ink that contains these, the solvent will soak into the urethane rubber. Urethane rubber cannot be used in this case.
When choosing a squeegee material, it is necessary to choose a material that is not compatible with the ink solvent.
The relationship between squeegee and solvent seems to be useless in "Oshidori couple".
