-Liner tapes are used in the process of paper tube making by wrapping a liner, which is a thin sheet of steel, around an inner mandrel. This helps to form the perfect cylinder shape and helps in protecting it from any damage, such as cracking or tearing due to tension.
–Liner tapes come with different materials and sizes that help in controlling the quality of end products. These tapes can be broadly classified into three types- aluminum tape, composite tape and jumbo tape. The choice between them depends on product specifications and end use requirements:
-Aluminum Tape: Aluminum tapes are made up of aluminum material and they come in varying thicknesses based on their widths. Such as – standard aluminum comes in widths ranging from 12mm, 18mm, 25mm to 38mm. This tape is used in products like – organic silica (OMS) tubes, soft tubes and other medium weight products which are used for paper transfer applications.
-Before applying aluminum tape to the liner mandrel it has to be cleaned with a wiping cloth or tissue paper dipped in alcohol based cleaner. The liner should be removed from its mandrel and then wiped with alcohol again. The solvent will help in evaporating any moisture left on the surface of the liner while being applied the tape.
-The next step involves removing any dust particles present on both the liner and aluminum tapes using an air blower nozzle. Dust particles can cause massive damage to the shell by penetrating into it during paper tube making process and result in the product having leaks.
–Aluminum tapes also come in two types – “split and non-split,” and can be easily identified by their thicknesses – 1mm or 0.8mm respectively. The split aluminum tape is more popularly used for paper transfer applications.
-Finally, it is important to note that ‘red liner’ should not be used with aluminum tape as the subsequent vacuum phase will bring out moisture from liner causing it to crack and break. This could lead to total paper tube failure during process stages like its drying phase and even cause serious damage due to extensive shrinkage which results into the formation of cracks.
-Composite Tape: Composite tapes are mostly made up of polypropylene, which comes in widths ranging from 12mm to 38mm based on the liner’s width. It has good resistance to chemicals and moisture and is widely used for paper products like packaging tubes, OMS fibers and other products that use paper transfer applications.
-Composite tape should not be applied over aluminum tapes as it can cause sticking during application stage itself or generate huge amount of heat because both types have different melting points (145 for composite tape vs 200 for aluminum). This could result into the liner sticking to the mandrel or inner surface of shell causing deformation or damage during drying phase. Before using it make sure that the liner used for product has been cleaned properly.
-Jumbo Tape: Jumbo tapes are mostly made up of polypropylene and come in widths ranging from 38mm to 76mm based on the width of liner being used. It is used with paper products which have higher weights like CEMTEX, OMS fibers etc where frequent changes of liner are required during molding process. Unlike aluminum tape it does not need any cleaning during application stage as it is non-sticky in nature. Moreover, there is no chance of sticking or bonding because jumbo tapes have good adhesive strength that helps to keep the two components together without creating any mess during paper product making process.