Roll-to-roll imprinting of two-sided structures on thermoplastic polymer film have been studied. Two continuous roll-to-roll approaches to producing structures on both sides of a web have been developed. In the sequential method, two separate printing units are used to the pattern upper and bottom surfaces of the film. In simultaneous roll-to-roll imprinting, two patterned rolls are used in one imprinting unit to pattern both sides simultaneously. In both experiments, flexible Ni-masters with submicron patterns wrapped on supporting metal rolls are used as stamps. The cellulose acetate film 95 µm thick and 50 mm wide has been used as the imprint material in the experiments. Patterned films were studied with an optical microscope and an atomic force microscope (AFM). The results indicate that both methods can be used for double-sided imprinting. However, in sequential imprinting, the first printed pattern is slightly damaged during the second printing phase.
- hot embossing
- cellulose acetate