Process for transferring microstructures to a final substrate
A process and a transfer film for transferring microstructures to a flexible or rigid final substrate that offers advantages in both speed and precision is provided. The inventive process involves subjecting a transfer film in a continuous roll-to-roll process to the following operations: either forming microstructures on, or transferring microstructures to a surface of the transfer film; and then transferring the microstructures from the transfer film onto a surface of the final substrate. The microstructures are single or multi-layer structures that are made up of: voids in a substantially planar surface, the voids optionally filled or coated with another material; raised areas in a substantially planar surface; or combinations thereof.
1. A transfer film for transferring microstructures to a final substrate, the transfer film comprising a carrier film having a planar surface on its side toward the microstructures, one or more fully cured binder layers on a surface of the carrier film, the microstructures, and one or more fully cured conformal release coating layers on a surface of the microstructures between the one or more fully cured binder layers and the microstructures, wherein the microstructures are single or multi-layer structures, each layer having one planar surface and an opposing surface that comprises: voids in a substantially planar surface, the voids optionally filled or coated with another material; raised areas in a substantially planar surface; or combinations thereof, and wherein the one or more fully cured binder layers is strongly bonded to the carrier film and to the one or more fully cured conformal release coating layers on a surface of the microstructures.
2. The transfer film of claim 1 , wherein the one or more cured binder layers is made up of one or more energy curable polyacrylates and a free radical photoinitiator.
3. The transfer film of claim 1 , wherein the microstructures are a single layer structure having one planar surface and an opposing surface that comprises: voids in a substantially planar surface, the voids optionally filled or coated with another material; raised areas in a substantially planar surface; or combinations thereof.