| Popis: |
This chapter discusses the steps involved in the classification and formulation of wood coatings. All wood coatings have something in common to distinguish them from other categories of coating, for example, for metal or masonry. It is important to recognize that formulating a wood coating imposes certain constraints on the selection of ingredients, but that there are still many choices and degrees of freedom on the permutations and combinations of raw materials that can be used to meet a defined need. Formulation has been defined as the science and technology of producing a physical mixture of two or more components or ingredients with more than one conflicting measure of product quality. This definition emphasizes two important aspects of formulation. Firstly that the emphasis is on the “physical mixture” properties; chemistry is involved in making ingredients but the physical properties of the wet and dry film are dominated by mixture properties, in particular the ratios between components. A second aspect of the definition underlines that there are conflicting measure of quality. This partly explains why there are so many different types of wood coatings; they present alternative solutions to the formulating problem. This chapter describes three broad areas in which formulation can be considered, i.e., classification, mixture properties, and composition. Classification can be by generic type or functional classification. Mixture properties include compiling of any of the four types of raw materials: binders, solvents, pigments, and additives. |
