Equipment Description:Wet-end Sizes
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By definition, a size is a product that imparts a resistance to wetting by fluids to paper and paperboard. The fluid tends to be water or water based, such as ink, milk, blood, fruit juice, etc. It can also be non-aqueous, such as oil or ink. Nearly all grades of paper and paperboard are sized to some degree. Without size the final product would either not function correctly, or lose it’s physical integrity, or both. Grades such as tissue, toweling and blotting paper are not sized. |
DESCRIPTION - Appearance, trade names, source? Today most sizes for use in the wet-end of a paper or paperboard machine are supplied as free-flowing liquids. The chemical types include natural based rosin dispersions and synthetic sizes such as stearic anhydride (SA), styrene maleic anhydride (SMA), alkyl ketene dimer (AKD), and alkenyl succinic anhydride (ASA). As fortified rosin soaps and pastes are generally not used these days, it is only ASA which has to be emulsified with other products on site at the mill. There are various suppliers of sizes: indeed, most of the specialty chemical suppliers now have sizes as part of their product offering. |
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PACKAGING & STORAGE - Type, precautions? Modern liquid sizes are generally delivered in 1 tonne semi-bulk plastic reinforced containers, or bulk road tankers for discharge into a bulk storage tank. Modern emulsions are very stable, but benefit by protection from extremes of heat. Products should be stored inside in cold weather regions, or held in trace heated and insulated bulk storage. In very hot climates, it might be necessary to insulate or refrigerate size products. |
Wet-end Sizes was also mentioned in the following Fact Sheets (6): |
(This information is from suppliers listed in the Industry Directory. Contact PITA to have your company listed here) There are 2 other potential suppliers of relevant equipment/services. (This information is from suppliers listed in the Industry Directory Contact PITA to have your company listed here) |