Henkel idea uses a laser in thermal lamination of nonwovens and films for sanitary and other applications
CLOVERDALE, CA, April 12, 2018-
Lamination is a common operation within the nonwovens industry and is conventionally practiced using thermal patterned calender rolls, hot melt adhesives or ultrasonic energy to bond two or more substrates. Nonwoven and film lamination is used to make a variety of important structures for the disposable hygiene market such as clothlike diaper backsheets and elastic nonwoven structures. Methods have evolved over time to improve control of the lamination process to reduce cost, avoid web deformation and to maximize strength, softness and durability.
In this patent application by Henkel AG & Co., a process and device are disclosed to laminate films with other films, nonwovens or textiles. The advancement utilizes a laser to pre-soften a thermoplastic film prior to lamination with a second substrate in a smooth roll calendar nip. The laser technology provides a large amount of energy in a short time and on a limited surface area. The laser-based film heating/softening occurs just prior to the nip in an energy-efficient process which does not require web cooling or discharge wasted heat into the equipment environment. This protects the machine components and reduces energy consumption. Thermoplastic polymer softening occurs only at the surface of the film and may be applied in a discrete pattern with a uniform temperature profile across the sheet prior to lamination. The heated area of the film may be brought into contact and laminated with a nonwoven in less than 0.01 seconds which is both thermally efficient and avoids undesirable mechanical distortion of the webs. The laser lamination process operates at a relatively high efficiency and conventional equipment can be easily retrofitted with a laser preheating unit.
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