15 июля, 2015 
Malyar This technique provides for the sequential addition of monomer so that particle morphology is manipulated, to meet optimum end-use requirements.
In essence, the technique involves changing the composition of the monomer phase in a sequential manner as the polymerisation progresses. This leads to a variation in polymer composition from the particle core to the particle shell.
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Patent literature reports many uses for this technology. One such example®, which has been commercialised, is the manufacture of voided acrylic latex particles, for use as opacifying pigments. This patent claims the preparation of a polymer by an emulsion technique consisting of the core of a highly carboxylated monomer composition. This is subsequently overcoated with a shell consisting of a much lower level of carboxyl containing monomer. Subsequent swelling of the particle by the addition of base causes a more rapid swelling of the core as the base penetrates the shell. When the system is subsequently dried to eliminate the water, voids are generated which provides opacity properties due to the increase in the refractive index.
A second example is the use of the core shell process to reduce the level of coalescing solvent, which may be required to generate the interpenetrated network.
A hard, high Tg core, surrounded by a softer, lower Tg and MFFT shell can reduce the MFFT to below the temperature of drying. In this way the particles coalesce much more readily.
A third example is the ICI patented® use of core shell emulsions for use in internal can lacquers. The particles are not as easily deformed during high pressure airless spray applications as are conventional water based systems. The shell could contain a crosslinking comonomer such as n-methylolacrylamide to enable the emulsion to be self crosslinking when stoved.
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