摘要：

In recent years a number of papers have been written concerning vacuum web coating of acrylate films onto a variety of substrates, for a variety of applications, utilizing the Polymer Multi-Layer (PML) process for flash evaporation of monomer fluids. While of interest to many, widespread implementation of the PML process has not occurred, in part due certain process limitations and stability issues. With traditional PML deposition a relatively long time is required for the process to reach equilibrium once liquid monomer flow to the evaporator is initiated, and a much longer time is required for gaseous monomer output from the evaporator to subside once the liquid monomer flow is terminated. This lack of instant-on/instant-off capability will be seen to be particularly problematic for in-line batch coalers. Further, control of the traditional PML process becomes increasingly difficult as web speeds decrease. This makes it difficult to match in-line deposition rates and line speeds with slower processes such as sputtering. There is also a tendency, with traditional PML evaporators, for the rate to decrease steadily with time as monomer polymerizes inside the evaporator and interferes with heat transfer between the walls and the freshly injected liquid monomer. A new Vacuum Monomer Technique (VMT), which utilizes a new low temperature source design to produce gaseous monomer, has been developed that allows vacuum deposition of acrylate films with the same properties (ultra smooth and pinhole-free) as PML deposited films. The new VMT process should permit sub-micron or multiple-micron thick films to be deposited at web speeds in excess of 100 meters per minute as in the PML process. However, unlike the PML process, the VMT process should also permit controlled deposition of very thin films at very low web speeds (100s of Angstroms thick at a fraction of a meter per minute). The VMT process should also be far more applicable to in-line batch coating processes than is the PML process since, for practical purposes, it can be turned on and off instantly. There is a large overlap between the classes of starting monomers used in the PML and VMT processes so a great deal of insight into the VMT process can be gleaned from the PML literature. The VMT process will be described, a complete mathematical description and model for the process will be developed, and data relevant to barrier films and optical coatings will be presented.

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