Kaolin has a very important role to play in the packaging industry.
Kaolin’s application in the adhesives industry is based primarily on its ability to control rheology. A unique challenge in the adhesive and sealant industry is the necessity of differing levels of viscosity and shear rates, during the mixing phase by the producer and the application phase by the end user. For instance, the producer will require low viscosity at high shear rate during production, and the end user may need high viscosity at low shear rate to prevent spreading of adhesives. A carefully chosen kaolin clay with suitable particle size and size distribution can be used to control both low and high shear viscosities during production, application and post application. The natural platy shape of kaolin clay provides good barrier properties in sealants by creating a tortuous path. Calcined kaolin clays with low surface moisture content results in excellent performance in moisture sensitive sealant applications.
The biggest industrial non-food use of starch is as adhesive in the papermaking process. Dextrin adhesives are used as a result of their low cost and ready availability. Adhesives for sealing cartons will have low and stable viscosity, are able to form strong bonds, and set up quickly. For remoistening applications such as tapes, stamps, labels, and envelope flaps adhesives must be capable of rewetting.
Kaolin are used in adhesives as a functional filler ,which aids in the rheology and viscosity of adhesive system, which is a critical parameter in its production and application, kaolin also aids in the dispersion of other ingredients. The fine particle size distribution, platy particle shape and surface charge of EICL Kaolin enables the functional properties in adhesives.