Roll embossing

Should the material still be hot when it leaves the embossing roll it will tend to stretch and to distort the effect. If a distortion is regular it may be acceptable but if film is released as a bow the embossing will reflect this as a curve across the width, which may be unacceptable. Distortion is particularly unacceptable with geometric and light-reflecting effects. 

A surface pattern can be applied by the calender roll or by a post-embossing operation. Feeding hot sheet to a cold embossing roll works well. The pattern is measured by a profilometer. 

Another way of obtaining the profiled films is by melt-embossing. The hot melt is extruded from a linear die into the nip formed by a plain roll and a V-grooved embossing roll. Cooling of the melt occurs on the cool roller and the embossed film is stretched and heat-set in the conventional way. The cross-section of the yams is uniform but the shape depends not only on the size and shape of the grooves but also on operating conditions and may approach the circular cross-section of spun filaments. 

Fig. 5-17. In-line vacuum forming embossing roll with water-cooled temperature control.

Valley printing (inlay printing) n. A printing process for flat plastic surfaces in which ink is applied to the raised portions of an embossing roll that simultaneously embosses the plastic surface and deposits ink in the valleys of the embossed surface. The process is similar to flexographic heating in that both print from raised portions of a cylinder. 

A Plateout Plateout can become an issue in plastisol molding operations as well as other plastisol applications where embossing rolls or other metal surfaces come in contact with the product surface. As plastisol molds are used repeatedly, material deposits can begin to form on the mold. These deposits can then cause defects in the final molded article. Plateout deposits that form on embossing rolls or other metal surfaces can also create surface defects in the final product. 

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