Emulsifier level

In summarizing the work of Miller and Mutka ( ), they have found that optimizing the cook temperature, emulsifier level and extrusion vessel pressurization permits the production of encapsulated flavoring of high flavor load. While the patent claims loadings up to 35%, the practical limit appears to be 16-20%. While this is comparable to the flavor loading typically... 

For the next run to narrow the small particle distribution, it was envisioned that emulsifier metering should be carried out rapidly over a short period of time. The metering would then be stopped for a given time so that micelle formation would cease. The emulsifier would be restarted to give enough emulsifier to stabilize the growing particles, yet not exceed the emulsifier level needed to cover all the growing particle surface area (not produce new micelles). With the aid of a computer controlled 190 liter reactor, this was accomplished in Run 11127-90. 

Figures 7. Simulated start-up of vinyl acetate polymerization at low emulsifier level (0.01 mol/L H20) under closed-loop control with arbitrarily selected controller tuning constants and manipulation of initiator flow rate at 50°C conversion in R1—STD feedback (--------------------------) vs. DTC (----)...

Tubular Reactor Studies. The first run in the tubular reactor was with the same recipe as for Seed I in Table I, but the conversion was very low, and there were two distinct phases. The residence time in the tube was equal to the batch reaction time. Apparently the more nearly constant temperature of the tubular reactor prevented rapid polymerization. In the next run, initiator and emulsifier levels were doubled, but still conversion was low, although phase separation was not so severe. With seed latex and still more emulsifier, Run I shown in Table II, monomer conversions of about 60% were obtained at 50 minutes average residence time in the reactor. No phase separation was evident, but later tests indicated that some phase separation was occurring. 

Figure 7. Size Exclusion Chromatography peak average diameters for three batch runs with different emulsifier levels runs BIO — Bll are replications.

Allyl polyalkylene Nonionic Copolymerizable emulsifiers Level of use 1-2%... 

Prior calculations showed that about 26% of a pure Technical would produce a 2 Ib/gal emulsifiable concentrate. This Technical normally averaged about 88% purity and would require 29.7% in the formula on an "as is" basis. Levels 1% above and below this value were chosen to give a reasonable range to fit within manufacturing specifications. Emulsifiers and emulsifier levels were chosen as a result of previous experience with similar systems. 

Figure 8 shows another experimental formula with a different solvent system. The active ingredient concentration is at a lower (200 gram/liter) level, also. The emulsifier levels tried here are higher and the resulting response surface has a broader shape. 

Latex stability. Effect of particle size and emulsifier level. Latex stability data for three latices with different particle size, are plotted in Figure 2. At a given emulsifier level, expressed as weight per cent of polymer, the stability increases with increasing particle size. The logarithm of the stability is a linear function of the emulsifier concentration (2 ) ... 

Figure 3. Mechanical stability of PVC latices. Effect of particle size and emulsifier level. Polymer 45% by weight. Na 0.01 mol/l.

Latex stability. Effect of temperature. Usually no temperature control was imposed. The rise in temperature during the test was 1-2 °C. For purposes of temperature control the bottle containing the sample was provided with a water jacket through which water at specified temperature was circulated. The effect of temperature on the stability is described in Figure 9 To avoid confusion the experimental points are not indicated on the figure, except those obtained at room temperature. The temperature dependence was found to obey the Arrhenius equation. At any given emulsifier level a linear plot of the logarithm of the stability versus 1/T could be obtained. 

Operotion/surface tension The reactor should be operated in such a manner that large transients in surface tension are avoided. Conversion and surface tension oscillations will tend to contribute to wall polymer formation. Start-up polides, system design, and control procedures should he selected to insure steady, free emulsifier levels in the particle formation reactor. In some cases it may also be desirable to add more emulsifier to downstream reactors. 

The higher emulsifier levels used for spread can produce tighter emulsions and the gelling or thickening agents can affect the rate and order that flavors are perceived. The flavor content and types must be defined to produce oral responses similar to the high-fat products. 

Details of the particle property model may be found in Kiparissides et al M,2] and Chiang and Thompson [3]. Following an approach used by Dickinson [4J and Gorber [5], the development was based on an age distribution analysis in which the classes of particles born between any time, t and T+dt, were followed through the reactor. The result was a series of differential equations in the total particle size properties (diameter, area and volume), the number of particles, conversion and the initiator and emulsifier levels in the reactor. 

The vinyl latex systems are similar to the solvent vinyl systems with respect to coating characteristics that is, they both have low coating viscosity. Removal of at least 50% of the coating weight as water requires ovens with minimum available temperatures of 212 °F. Since organic solvents are not present, fire hazards are diminished. The high emulsifier levels in these systems will limit their applications where water contact or sensitivity are important... 

Ekaline . [Sandoz Prods. Ltd.] Detergent wetting agent emulsifier, leveling agent dispersant for dyeings, scouring. 

Lomar . [Henkel/Emery Henkel-Nopco] NafAdialene sulfonate condensates emulsifier, leveling agent, dispersant suspending agent stabilizer for emulsion polymerization, dyestuff mfg., ceramics, paint paper, rubber, agric. formulations. 

Merpol . (DuPont] EO condensate wetting agent, detergent, penetrant, emulsifier, leveling t ent, dye assistant, an-Ustat, emulsifia, stabilizer fw textile, paper, paints, inks, medichial ointments, antiperspirants, cosmetics. 

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