Paper foam breaking

Uses Surfactant, defoamer for syn. resin emulsions, emulsion-type adhesives, emulsion-type paints, latex prod., textiles, wastewater, paints, inks, dyes, mbber, plastics, paper Industry, recovery of pulping liquor Features Good foam breaking long lasting defoamIng Properties Lt. yel. liq. sp.gr. 0.90 pH 9.0 (3% aq.) 100% solids Use Level 1-100 ppm (paper industry) 0.05-0.5% (textile dyeing)... 

Uses Aniitbam for fermentation, paper/pulp, metal, phannaceuticals, cosmetics, syn. resin paint pigments, textiles, and wastewater treatment detergent in auto dishwash, bottle washing, etc. suitable for org. acids, amino acids, and antibiotics Features Good foam breaking/prevention Properties Transparent liq. 

In a third paper by the Bernard and Holm group, visual studies (in a sand-packed capillary tube, 0.25 mm in diameter) and gas tracer measurements were also used to elucidate flow mechanisms ( ). Bubbles were observed to break into smaller bubbles at the exits of constrictions between sand grains (see Capillary Snap-Off, below), and bubbles tended to coalesce in pore spaces as they entered constrictions (see Coalescence, below). It was concluded that liquid moved through the film network between bubbles, that gas moved by a dynamic process of the breakage and formation of films (lamellae) between bubbles, that there were no continuous gas path, and that flow rates were a function of the number and strength of the aqueous films between the bubbles. As in the previous studies (it is important to note), flow measurements were made at low pressures with a steady-state method. Thus, the dispersions studied were true foams (dispersions of a gaseous phase in a liquid phase), and the experimental technique avoided long-lived transient effects, which are produced by nonsteady-state flow and are extremely difficult to interpret. 

Considerable progress has been made in foam and entrained air management in the pulp and paper industry since the inhoduction of petroleum as a defoaming aid. Because of the complex nature of the paper mill system and the fact that the chemically stabilized foams generally encountered are hard to break down mechanically, more mills are finding it not only helpful but necessary to use chemical defoamer formulations. These are generally emulsifiable combinations of hydrocarbons, alcohols, fatty acids, and various surface active agents, that frequently are specifically formulated for particular applications. 

Often referred to as carbonaceous materials (carbon based) these include wood, cardboard, paper, hard-board, soft furnishings such as carpets and curtains and materials such as plastics, foam rubber and even metal. As the structure of solids is based upon tightly formed particles, those, such as metals (unless reactive, i.e. magnesium) are very difficult to break down and require substantial heat sources to be applied for a fire to be initiated. 

This is important because as the material is mixed, air is inadvertently whipped into the system which, if retained during fusion, could cause voids in the final product. Two tests are common a syringe is used to inject a defined volume of air into the plastisol contained in a paper cup. The time for the air to rise to the surface and break is the measure of air release alternatively a cup of plastisol is put into a vacuum chamber and as vacuum is applied the rising foam or head is measured. 

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