| 摘要 |
PROBLEM TO BE SOLVED: To provide a flexible letterpres superior in solvent resistance and capable of being coated with a solvent type ink containing a polar solvent or a coating material to form a printing or design or pattern plate by forming the surface of a plate with polyurethane. SOLUTION: The plate surface (printing plate surface or coating surface and the like) is formed with the polyurethane polymer composed essentially of urethane bonds, and generally obtained by reaction of an active hydrogen compound with polyisocyanate. The active hydrogen compound is a compound having >=2 of an active hydrogen-containing-group in the molecule, such as hydroxyl or carboxyl or amino group. Preferable active hydrogen compound is various kinds of polyols, alcohol having >=2 hydroxyl groups in one molecule. The obtained solvent-resistant flexible letterpress is superior in resistance to polar solvents because of the printing surface made of polyurethane, and since the flexibility of the plate is not impaired, it can be used for flexography. |
