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Surface sizing solutions consist of mainly modified starches and sometimes other hydrocolloids, such as gelatine, or surface sizing agents such as acrylic co-polymers. Surface sizing agents are amphiphilic molecules, having both hydrophilic (water-loving) and hydrophobic (water-repelling) ends. The sizing agent adheres to substrate fibers and ...
Cold sizing is a squeezing operation performed at temperatures significantly below the melting point to finish the surface of a workpiece to ensure better dimensional accuracy and surface finish. The sizing operation is a squeezing operation that minimizes the thickness of the metal .
When the paper industry started using chalk instead of china clay as filler, the paper chemistry had to switch to a neutral process. At several places AKD (alkyl ketene dimer) and ASA (alkenyl succinic anhydride) are used. Latest development is to use surface size, [5] which is applied using a size press. The advantage of surface sizing is that ...
An optimal particle size of about 1 μm is obtained with high shear. The benefits of ASA when used in paper sizing include: [15] Applicability in neutral to slightly alkaline pH range (optimal pH 6-8) - AKD even pH 5-9) High reactivity leads to hydrophobing already in the wet end of the paper process
The surface chemical composition is differentiated by the adsorption of acrylic acid or an anionic surfactant, both of which are used for stabilization of the dispersion in water. [4] Co-binders , or thickeners, are generally water-soluble polymers that influence the paper's color viscosity, water retention, sizing , and gloss.
Mineral processing can involve four general types of unit operation: 1) Comminution – particle size reduction; 2) Sizing – separation of particle sizes by screening or classification; 3) Concentration by taking advantage of physical and surface chemical properties; and 4) Dewatering – solid/liquid separation.
Enzymatic desizing is the classical desizing process of degrading starch size on cotton fabrics using enzymes. Enzymes are complex organic, soluble bio-catalysts, formed by living organisms, that catalyze chemical reaction in biological processes. Enzymes are quite specific in their action on a particular substance.
Mechanical screening, often just called screening, is the practice of taking granulated or crushed ore material and separating it into multiple grades by particle size.. This practice occurs in a variety of industries such as mining and mineral processing, agriculture, pharmaceutical, food, plastics, and recycling.