Sizing internal

Internal Sizing. The most widely used internal sizes are alkyl ketene dimers (AKD), alkenylsuccinic anhydrides (ASA), and rosin-based sizes that are used with papermaker s alum (aluminum sulfate with 14 waters of hydration), polyaluminum chloride (PAG), or polyaluminum siUcosulfate (PAS) (61). The rosin-based sizes are used under acidic conditions. Since the mid 1980 s there has been a steady conversion from acid to alkaline paper production, resulting in static to declining demand for the rosin-based sizing systems. Rosin is a complex mixture of compounds and consists primarily of monocarboxyhc acids with alkylated hydrophenan threne stmctures (62). A main constituent of wood rosin, gum rosin and taH-oil rosin is abietic acid. 

In most cases, some internal size is stiU required to control the depth or penetration of the surface size, the mimabiHty through a size press, or other properties. Surface sizing reviews and leading references are available (66,67). 

Internal size classification plays an essential role in the funclion-ing of machines for dry grinding in the fine-size range particles are retained in the grinding zone until they are as small as required in the finished product then they are aUowed to discharge. 

When replacing relief valves, care must be taken to make sure that the right relief valve is replaced. Section 6.1 (d) describes another incident that occurred when a flare line was broken. Valves of different internal sizes may look alike (see Section 1.2.4). 

Internal reflection, 24 111-112 Beer s law expression for, 24 113 Internal resistance, batteries, 3 410 Internal return rate (IRR), 9 544-545 Internal sizing, in paper manufacture, 18 109-113... 

Internal sizing may be carried out over a wide pH range, but it is popular now to use neutral or slightly alkaline systems. When successfully performed, it retards the rate of penetration of a fluid through capillaries formed both within and between fibres. The fluid involved is, for most commercial grades of paper, water but resistance to non-aqueous fluids may also be important in some applications. This discussion will concern itself only with sizing against aqueous systems. 

Sometimes internal sizing agents such as alkyl ketene dimers and... 

Since the early days of machine made paper in the first half of the nineteenth century, the most widely applied method of Internal sizing has been the use of naturally occurring resinous materials ("rosins") in conjunction with an aluminium salt, usually aluminium sulphate (called "alum" by paper-makers). Various forms of rosin sizes (rosin soaps, rosin emulsions, fortified rosins) have been developed over the years to improve the process, but these variants still involve the use of alum as a means of ensuring that fibres retain a layer of size. 

Synthetic sizes, such as styrene maleic anhydride (SMA) copolymer or anionic polyurethane (PU) emulsion, are often added to starch-based surface size to develop water resistance, particularly in the production of label grades. This procedure may permit reducing or eliminating the use of internal size.216... 

Player s No. 10 Extra MM 04 19 Lambert Butler International Size ... 

Paper Sample Pulp Composition pH Internal Size... 

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