Granulation particle formulation

To improve solubility, an appropriate particle formulation with fast-dissolving additives might be tried first (see example for NOBS in Ref. 145). Alternatively or additionally, disintegrants may be used. This is described in Ref. 146 for a peroxycarboxylic acid combined with swellable polymers such as carboxymethylcellulose. On the other hand, the primary particle size of the active material prior to granulation could be considered, since smaller particles typically show a shorter dissolution time, and if residues are inevitable, are likely to be less visible. If necessary, combinations of both measures (suitable additives and small particle size) may be employed. Several examples are described for the granulation of a manganese catalyst in Ref. 147. 

Because of high turbulence in the spout and the regularity of particle mixing, different types of spouted bed are highly appropriate to the placement of spray nozzles for the purpose of particle formulation, such as granulation or coating. Two examples in which liquid spraying occurs directly at the entrance of the gas jet, and which results in a concurrent, upward flow of the droplets and gas with frequent droplet-partide collisions, are shown in Fig. 4.3. The equipment shown in Fig. 4.3a is of the conical-cylindrical type, whereas the cylindrical device of Fig. 4.3b is named Wurster equipment, after its inventor (Wurster, 1959). The main feature of... 

Many friction material formulations contain 5—15 wt % of friction particles, the granulated cross-linked products of the reaction of CNSL, a phenol substituted at the meta position with a unsaturated side chain, and formaldehyde. Friction particles range in size from 50 to 500 p.m. They reduce frictional wear and increase pedal softness (86). 

FIG. 20-82 Capacity of inclined disc granulators of varying diameter and formulation feed densities. Capes, Particle Size Enlargement, Elsevier, 1980. )... 

Injection moulding compositions have a number of requirements with regard to granule flow and cure characteristics not always met by conventional formulations. For example, granules should be free-flowing (i.e. of a narrow particle size distribution and not too irregular in shape). There are also certain requirements in terms of viscosity. 

Solids handling frequently has the potential for dusting, which can lead to potential health and explosion hazards. Handling solids in the form of larger particle size granules or pellets rather than a fine powder reduces the potential for worker exposure. Worker exposure hazards are reduced by formulating dyes as liquids or wet pastes rather than dry solids or powders (Burch, 1986). 

Dry products can include dusts, powders, and granules. Dusts and powders are manufactured by mixing technical grade material with the appropriate inert carrier and grinding the mixture to obtain the correct particle size. Several rotary or ribbon blender-type mixers mix the product. Figure 6 shows a typical dry formulation unit for pesticides [8]. 

The effects of particle size on detonation rate have been studied by observing the functioning of mixes of various granulations in pressed expl charges, and the influence of cryst size on the props of castings of formulations, such as of Comp B. 

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