The product is widely used for the sealing and protection of various flat materials such as ID cards, historical and cultural materials, photos, images, credit cards, licenses, business licenses, precious correspondence, securities, passbooks, certificates, etc. The sealed flat materials have excellent functions such as water resistance, anti-erasure, moisture resistance, insect resistance, mold resistance, and resistance to general acid and alkali chemicals corrosion. They also have a straight and beautiful appearance, improving transparency.