Wet End Applications
ASA: An emulsion of ASA is prepared with cationic starch or polymer by passing through high shear equipment. The ASA emulsion imparts resistance to water penetration of paper or paperboard. The advantage of using ASA is that full curing is achieved on the machine. This is not the case with less reactive sizing agents such as AKD.
Optical Brighteners: OBAs are added to the wet end and/or size press operations in order to improve the brightness of the paper. OBA's absorb ultraviolet light and then give off visible light in the blue-white range. This results in a whiter and brighter paper.
Dry Strength: Dry Strength agents are polymeric additives generally added to the wet end in order to improve fiber bonding. This has the effect of increasing strain resistance, e.g. tensile strength, tear strength, or crush. Many widely used polymer-based additives have the disadvantages of low solids (8%) and short shelf life (<1 month). Bercen, Inc. is introducing a patented technology that will provide the same strengh properties using much higher solids polymers (40%) saving a great deal of freight costs.