Thin Microcellular Plastic Sheet Incorporating Designed Foaming Patterns Made by Photochemical Foaming Technology

Abstract

A novel chemical foaming technology is proposed to manufacture microcellular plastic sheet with a thickness of 100 μm or less. A foamable plastic consisting of a polymer with t-butyl ester groups and a photoacid generator has been developed. Upon ultraviolet irradiation, the photoacid generator releases protons. The protons transform the t-butyl ester group attached to the polymer into isobutene gas upon heating, which leads to controlled microcellular formation in the plastic film. The cell size and the cell density of the microcellular plastic are controlled by ultraviolet irradiation and the heating temperature. By adjusting these two parameters, the optical properties of the resulting microcellular plastic can be predetermined. A thin microcellular sheet that has a micron-order foaming pattern exhibiting different transparencies has been produced by using a pattern mask.

Keywords

thin microcellular plastic sheet designed foaming pattern t-butyl ester group isobutene gas optical devices

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