-The direction of elongation is also "non-straight film"-
In our daily life, we use various films.
For example, polyethylene wrap when heating food in a microwave oven, cellophane tape for fixing paper,
Vinyl tape on electrical cord clothing, plastic bottle labels...
For example, polyethylene wrap when heating food in a microwave oven, cellophane tape for fixing paper,
Vinyl tape on electrical cord clothing, plastic bottle labels...
Now, what do you think happens when you heat these films?
The reason why I ask this question is that in screen printing, there is a process of drying the ink after printing.
In many cases, heat drying is used, and when printing on film, it is necessary to think carefully about what happens to the film with heat.
Because you will make a big mistake.
The reason why I ask this question is that in screen printing, there is a process of drying the ink after printing.
In many cases, heat drying is used, and when printing on film, it is necessary to think carefully about what happens to the film with heat.
Because you will make a big mistake.
Now consider the case of metal. For example, railroad rails.
The rails are made of iron, so they expand with heat.
Railroad tracks are connected for long distances, so they stretch considerably during the hot summer months.
Therefore, there is a mechanism to absorb this elongation here and there.
The rails are made of iron, so they expand with heat.
Railroad tracks are connected for long distances, so they stretch considerably during the hot summer months.
Therefore, there is a mechanism to absorb this elongation here and there.
Even with screen printing, there are cases where continuous printing is performed on a roll of PET film.
Heat of about 120°C is applied to dry the ink.What will happen to the PET film at this time?
Does it extend like a rail? In the case of PET film, the situation is a little more complicated.
Heat of about 120°C is applied to dry the ink.What will happen to the PET film at this time?
Does it extend like a rail? In the case of PET film, the situation is a little more complicated.
I had an experience like this in the past.
One time, I was printing on a material that was laminated with PET film.
This material has a structure in which a flame retardant is sandwiched between PET films.
It was a material that had the characteristic of being less flammable than general PET film.
First, the prototype went well. However, when mass production begins and the material manufacturing lot changes...
This material has a structure in which a flame retardant is sandwiched between PET films.
It was a material that had the characteristic of being less flammable than general PET film.
First, the prototype went well. However, when mass production begins and the material manufacturing lot changes...
I can't make a product...
For some reason the film curls after printing and drying! !
Even though the printing conditions have not changed? ?
For some reason the film curls after printing and drying! !
Even though the printing conditions have not changed? ?
Even if I change the drying conditions of the ink in various ways, the curl does not go away.
It was known that PET film shrinks when heated.
I didn't understand why it curled.
After looking around, due to the manufacturing method, PET film does not expand when heated.
This trait was discovered.
It was known that PET film shrinks when heated.
I didn't understand why it curled.
After looking around, due to the manufacturing method, PET film does not expand when heated.
This trait was discovered.
PET film is made by a method called biaxial stretching.
In other words, the film is made by pulling it vertically and horizontally.
Therefore, the direction of thermal expansion differs depending on the location of the film.
In other words, the film is made by pulling it vertically and horizontally.
Therefore, the direction of thermal expansion differs depending on the location of the film.
When films with different expansion directions are pasted together, curling occurs when heated.
It is possible to prevent curling by pasting materials with the same direction of expansion,
Materials have become quite expensive.
It is possible to prevent curling by pasting materials with the same direction of expansion,
Materials have become quite expensive.
This phenomenon also occurs when films made of different materials are laminated together.
For example, PET film and metal film also curl due to the difference in thermal expansion coefficient.
For example, PET film and metal film also curl due to the difference in thermal expansion coefficient.
When printing on laminated materials, it is necessary to carefully check the characteristics of the materials.
