The function of the compliant covering in embossing applications is to provide a surface that is capable of accepting the respective non-compliant image (Engraved Pattern Roll). The objective is transfer the image from the engraved roll to the substrate as it passes through the nip.
Rubber coverings are used for compliance due to their ability to form or comply to the surface of the engraved pattern. Elastomeric coverings for embossing applications must exhibit certain physical properties to function well in the embossing arena. This includes resiliency, abrasion resistance, modulus, and low hysteresis properties. These properties will determine the suitability of the covering in the application and will greatly impact the degree of success in a given environment.
The selection of the elastomeric covering is based upon the following application variables which relate to the previously mentioned physical properties.
Emboss Pattern Design
PLI Load
Line Speeds
Roll Diameter
Recycled Versus Virgin Fiber
Basis Weight
These operating parameters in the embossing application have a dramatic impact on the selection process since each elastomeric covering has its own inherent physical properties and limitations.
The emboss pattern has a significant impact on the operating environment since this will determine the degree to which the covering must comply. Engraved patterns with more intricate pattern depth and density require a covering that can comply with the engraved image and recover completely prior to re-entry into the nip. As the complexity of the engraved pattern has evolved the degree of importance on the
compliant covering has increased. Likewise macro patterns require less from the covering since most elastomeric materials recover to some degree.
The degree of loading between the compliant and non-compliant covering also has an impact on the overall operating environment since the load itself will determine how much the covering must conform to the pattern and the length of dwell time in operation. The higher the load in the application the wider the nip flat will become and the degree of conformance of the compliant covering increases.
Application line speeds essentially determine how quickly the compliant covering must completely recover from distortion by the engraved pattern. The faster the line the runs the greater the demand on the compliant covering to recover from deformation. As line speeds increase the relevance of compliant covering hyteresis can be seen. In other words as line speeds increase the elastomeric coverings must exhibit outstanding hysterectic properties.
Engraved and compliant roll diameters are another application variable that can impact the operating environment for embossing applications. The relevance of this is related to the degree at which line speeds and PLI loading impact the environment. As roll diameters increase the actual impact of line speed and pressure is less of an issue since the compliant covering does not have to recover from deformation as quickly. It should be noted that a limitation with older rewinder’s can be related to the size of the rolls and engravings since increasing the line speed may create an environment which may become too severe for the compliant covering to withstand.
Valley Roller is pleased to offer our novel coverings to the embossing market. Each of these coverings have been specifically designed and tested for the embossing market. We believe these coverings offer the reliability and durability necessary to help our customers make superior embossed products with enhanced durability and life. Please review the chart on the last page for a listing of our product line.
Val-Coat®
Hardness: 3-225 P&J
These proprietary families of coverings were developed for high performance applications requiring superior mechanical toughness durability, and low hysteresis. These coverings simply out perform typical embossing rubber coverings especially at higher operating pressures and speeds. We have found these coverings will outlast conventional coverings by 1.50 Times.
Applications: Tissue, Towel and Napkin Embossing, Marrying Rolls
Stratum-Coat®
Hardness: 80-160 P&J
This is a dual durometer covering that was designed for embossing applications requiring wider nip flats, superior mechanical toughness durability, and low hysteresis. These coverings simply out perform typical embossing rubber coverings especially at higher operating pressures and speeds since the outer surface of these coverings is based on our proprietary Val-Coat® technology.
Applications: Tissue, Towel Embossing
Cool Nip™
Hardness: 100-160 P&J
This family of coverings was designed for high speed applications requiring superior low hysteresis. These coverings run cooler than typical embossing rubber coverings especially at higher operating pressures and speeds.
Applications: Tissue, Towel
Cool Nip™ Stat
Hardness: 100-160 P&J
This family of coverings that was designed for high speed applications requiring superior low hysteresis and static dissipating properties. These coverings are electrically conductive and enable the covering to eliminate static build-up during converting operations. Cool Nip Stat simply runs cooler than typical embossing rubber coverings especially at higher operating pressures and speeds.
Applications: Tissue, Towel
Urelast™
Hardness: 40-180 P&J
This family of coverings was designed for Towel Embossing applications requiring superior mechanical toughness durability, and low hysteresis. These coverings simply out perform typical embossing rubber coverings especially at higher operating pressures and speeds.
Applications: Towel Embossing
Val-Rite™ and Val-Rite Plus™
Hardness: 15-75 P&J
This family of coverings was developed for converting applications requiring resistance to water based adhesives, while exhibiting mechanical toughness durability, and low hysteresis. These coverings simply out perform typical applicator and marriage roll coverings.
Applications: Glue Fountain, Glue Applicator and Marriage Rolls
