Sorts of labelling adhesives
www.labellingadhesives.comFor those many different applications are differente labellingadhesives avaiable. Important for the right choice of adhesive are the products you want to label and the labels itself. The application (machine, speeds) are important for the right choise also. A good labelling adhesive is not allowed to smear, splash, dry on the roller and has to flow well, must be reasonable in open time en must keep the moisture in it as long as possible in order not to affect the fibres in the label too much. A good choise is not always difficult to make.
Adhesives based on casein
Casein adhesives are based on proteins, these adhesives are unique because of their fast increasing wettack when the adhesive is cooling down. This process is eagerly used in the beer industry. Because of this behavior the beer industry can get capacities over 80.000 bottles per hour. Casein adhesives are the basis for labelling bottles of glass. Caseins can be icewater resistant, mostly caseins are easy to clean with pure water.
Synthetical labelling adhesives for e.g. plastics
Synthetical adhesives are often used for bonding on difficult substrates like heavily coated glass bottles or plastic bottles. Synthetic adhesives do not have that high wettack as casein adhesives on room temperatures, but on warm or hot products their tack is even better then with . Most synthetic adhesives are used on bottles of PE/PP/PET.
Synthetic adhesives for non plastic substrates
A second group of synthetical adhesives has especially been develloped for standard glas and carton applications. The adhesive has very nice drying properties, a good flowing character and is easily cleaning.
Starch labeling adhesives
Starch labelling adhesives are used at simple, dry applications for glass and carton. Especially on carton these adhesives have perfect drying characteristics.
Dextrine labelling adhesives
Dextrine adhesives have a high tack (initial bond) but mostly have a less good final bond because of their brittle gluefilm. Dextrin adhesives are mostly used for can labelling en carton substrates.
Hot melt labellingadhesives
Hot melts are used for many different applications in the labelling industries. On ass well horizontal as vertical (rollthrough) machines hot melts are used for pick-up and glue lap of the label. The large advantage of hot melts above conventional waterbased adhesives is their large versatility.
Pick up vertical
Vertical pick up hot melts are applied to the can (bottle or pot). The can takes then a label from the magazine (pick up). These pick up hot melts could be applied with roller systems as well as with spray nozzles. The hot melt must have a strong initial tack en must not spin.
When the can almost has made a whole turn (360 degrees) the gluelap adhesive is applied (roller or spray). Then the label is being pressed at the glue lap. It is very important that the hot melt does not smear. Depending on circumstances you could consider to use a different hot melt for the glue lap then the pick up. This will depend on your requirements, circumstances and wishes.
Pick up horizontal
Most horizontal labelling machines are old and initially developed to work with dextrine adhesives. Many machines are rebuilt to work with a hot melt for pick up. Usually a machine could produce twice as fast when it used hot melt for pick up. Important characteristic of the hot melt is non spinning..
Most glue lap adhesives on horizontal machines are polymer dispersion adhesives. A quite simple but stable system. The adhesive is mostly applied under pressure through a little pipe with holes.