Dispersing aids

Water-Based Writing Inks. These consist of very fine pigment dispersions in aqueous media containing small amounts of glycol or glycerol and a dispersing aid. They dry mainly by evaporation and quick wetting of ceUulosic fibers in paper substrates. 

In the wet process, the clay is masticated in a pug mill to break up lumps and then dispersed with a dispersing aid and water to make a 40 percent solids slip of low viscosity. A hi -speed agitator such as a Cowles dissolver is used for this purpose. Sands are settled out, and then the clay is classified into two size fractious in either a Hydrosettler or a continuous Sharpies or Bird centrifuge. The fine fraction, with sizes of less than 1 [Lm, is used as a pigment and for paper coating, while the coarser fraction is used as a paper filler. 

Liquid raw materials such as polymer emulsions, defoamers, pigment dispersions, dye solutions, dispersing aids and emulsifiers are all products that can themselves become infected with micro-organisms if not produced from non-contaminated ingredients, under good manufacturing conditions and with an effective preservative. 

When formulating a deflocculated system, a number of materials may be used as dispersion aids. De-flocculating agents include polymerized organic salts of... 

Additives are present in a paint in small amounts (typically less than 5 wt %), but can have a marked effect on the paint properties. They include antifoam, antisettling, and antiskinning agents, can-corrosion inhibitors, driers, dispersion aids, and many more. Details of these can be found in many books (e.g. Lamboume and Strivens, 1999). 

Various investigations have considered the effects of titanate treatments on melt rheology of filled thermoplastics [17,41]. Figure 10, for example, shows that with polypropylene filled with 50% by weight of calcium carbonate, the inclusion of isopropyl triisostearoyl titanate dispersion aid decreases melt viscosity but increases first normal stress difference. This suggests that the shear flow of the polymer is promoted by the presence of titanate treatment, and is consistent with the view that these additives provide ineffective coupling between filler particles and polymer matrix [42]. 

The purely mechanical dispersion of the agglomerates can be assisted by the addition of dispersion aids (e.g., amide, polypropylene or polyethylene waxes, metal carboxilates, organic fatty acids and their esters), which wet the particle surfaces, thus reducing the interaction between them (see Fig. 4.14 and Chapter 9) [19]. This significantly lowers the shear stresses required to disperse the agglomerates. 

K. Hyche, R. Hollis, Eastman Chemical Company, Preliminary Studies of Improved Dispersing Aids for Fluorescent Pigments in Polyolefin Plastics . Technical Conference of the Society of Plastics Engineers, Oak Brook, IL., P. 148. 

Silica fillers play a prominent role in the paste rheology of polyurethane and rubber coating mixtures. Silica fillers are also used for surface matting. In polyurethanes, the layer thickness is even thinner than is used with PVC. Dispersion is enhanced by dispersion aids. Fillers are used at relatively low concentrations in PU formulation. But in rubber coatings, large quantities of calcium carbonate are used to decrease cost. Rheology and reinforcement are adjusted with carbon black. 

Agent 765. [VifitcoSA] Fatty amine salt corrosion inhibiter, i gment grinding and dispersion aid antistrippbg agent for paints. 

Lan-Aqua-SoL [Fanrung] PEG-75 lanolin emulsifier, emollient superfatdng agent condidoner for cosmedcs, pharmaceuticals, household detergents solubilizer, wetting agent dispersing aid. 

Proaid. [Akrochem] Processing and dispersing aid, homogenizing agent softener for rubbers, unsaturated polymers peptizing agent for natural and polyiso-prene rubbw. 

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