Profile wrapping applications show continuously increasing requirements for more efficient, faster manufacturing processes as well as stronger bonding adhesives. Nowadays a multitude of substrates, such as wood-
based materials, plasticss and metal are wrapped with a great variety of foils. Profiles serve many different applications such as:
PUR hot melts are used for instance when the products have to meet special demands regarding to moisture, cold- and heat resistance. PUR hot melts mostly provide a stronger adhesion. PUR hot melts are high efficient adhesives for demanding bonding requirements. PUR hot melts are now the standard adhesives for metal profiles and for difficult to bond, plastic foils. Still, regurlarly new raw materials are introduced to develop even better adhesives. This enables various industries to continuously increase processing speed and automation levels.
Wood veneer
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Wood veneers are divided into two major groups: rotary cut veneer and sliced veneer. Sliced veneer is the most commonly used veneer in profile wrapping. The complexity of the core material dictates the quality of veneer to be used.
Manufactured fleece-backed veneer, as a fleece is glued on the back of the veneer. The veneer becomes more flexible due to the glued-on fleece.
The quality of symmetric and asymmetric finger-joint veneer is visible after the lacquering process. In the case of poor quality, two different pigmentations are visible. Different pigmentations are avoidable using veneer with an aluminium indicator.
Veneer with an aluminium indicator is always in roll form. An aluminium strip is applied at the joint between the veneer sheets. This type of veneer needs to be ordered with a specified sheet length within the roll of veneer. The sheet length needs to be 1’’ longer than the profile it will be applied to allowing for some length variations in the substrate. The advantage of the aluminium indicator is, that the finger-joint strip will not be placed on the profile and ruin its aesthetics. This is accomplished by using sensors on the machine to pinpoint the position of the aluminium indicator at the joint. The signal is used to position the substrate with the aluminium indicator in the veneer roll. Doing it this way, the beginning of the veneer sheet is certain to be synchronous with the beginning of the substrate.
Paper
Different paper types are available for profile wrapping. Paper for profile wrapping is usually made like a sandwich. It starts out with the base paper that is also referred to as the backer. The backer is available in different colours and different weights. The second layer is the decorative layer. The decorative layer can be of a solid colour or with a printed pattern. Usually 30g paper, this decorative layer is laminated to the base paper. The colour of the finished paper depends on the colour of the base paper. These papers can range from 30 to 300 g and more. Most commonly used papers are 60 or 80 g papers. They can be wrapped around very complex profiles and at the same time they are not as fragile as 30 g paper. Paper can be wrapped around sharp edges (with the exception of very heavy papers).
Laminates
Laminates are decorative surface papers impregnated with melamine resins and then pressed over strong paper core sheets impregnated with phenolic resin. These sheets are then bonded at pressures exceeding 200 kg/cm2 at temperatures approaching 150°C. Finished sheets are trimmed and the backs are sanded to facilitate bonding. Laminates are more difficult to wrap in comparison with wrapping paper, because papers are more flexible. The variety of laminates ranges from high-pressure to low-pressure to continuous laminates. There is a difference in the way these laminates are manufactured as well as in the flexibility of the material. Sharp edges are not recommended. For the flooring industry the laminates are coated with aluminium oxide.
In case of profile-wrapping with laminates, an extremely long wrapping zone is necessary. The temperature of the laminate, if corners are to be wrapped, must reach 300° C in the relevant area.
Vinyl (films)
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