Chalk is a tool for writing and drawing, which is mainly used for writing and drawing on chalk boards, blackboards and whiteboards. Traditional chalk is mainly composed of lime and gypsum, which is brittle and hard and not very environmentally friendly. Modern chalk uses emerging materials, such as polystyrene (PS), polycarbonate (PC), polyethylene (PE), polypropylene (PP), polyester (PET) and other plastic materials. These plastic materials are more environmentally friendly and easier to store and carry than traditional lime and gypsum.
The method of making chalk includes two steps: crushing and mixing. Crushing is to bind raw materials such as polystyrene ester into solid, and then crush it into powder. Mixing is to mix powder and water into paste, inject it into a molding machine, and make it through a series of technological processes such as molding, drying and screening. Chalk generally smells like chalk (because calcium carbonate is added), but colored chalk can also be made by adding colored materials of different colors.