Enhancement of Dry Content in Coating Solution for Functional Packaging

Abstract: The main goal for a packaging is to protect the product inside. Typical packaging nowadays is made of layers of paper and barriers consisting of plastics or aluminum foil. A problem with the barrier used today is the environmental thinking. Xylophane® is an environmental friendly and biodegradable alternative to the current barrier material used in packaging. It consists of the natural carbohydrate xylan and additives. Xylophane® is an efficient barrier to oxygen, grease and aroma and can prolong the shelf life of sensitive food. The raw material xylan is water soluble and Xylophane® can be coated on paper, board and plastics without using other solvents. A problem with the drying process is the amount of energy needed and the consumption needs to be decreased. Also, the drying capacity of the equipment to be used is often limited and the amount of water to be dried off is critical for the success of the coating process. By increasing the dry content of Xylophane® without increasing the viscosity too much, the drying process can be more effective. In this thesis, studies were made of using a filler as an additive to increase the dry content without destroying the barrier properties. With an experimental design, a suitable relationship between the ingredients xylan (X), plasticizer (P) and filler (F) was found. Xylan is the main component and is needed to get a good oxygen barrier. The plasticizer decreases the oxygen barrier properties but is needed to make the material more flexible. The filler is positive for the barrier properties. The chosen composition was X:P = 7:3 and X:F = 1:1. Some extra experiments were made to find a reasonable value of the dry content. Dry contents around 18 % work well with temperatures at and above 45°C, but to manage to perform coating at room temperature the dry content needs to be lower.