WHITE MASTERBATCHES

It is a well acknowledged fact that White Masterbatches constitute the second largest masterbatch production of all the masterbatches. Although various white pigments can be used to make these White Masterbatches, Titanium Dioxide is largely used in plastic applications because of its unique properties. Titanium Dioxide has a refractive index better than any other white pigment. It is produced with two different crystal structures, anatase and rutile. When produced at the correct crystal size, titanium dioxide is a highly efficient scatterer of light, imparting whiteness, an opacity to the medium in which it is dispersed. These properties ensure the unique superiority of this pigment. Crystal size affects opacity and in systems where titanium dioxide loading are very high. Plastics by comparision normally use relatively low loading and the optimum is reduced to about 0.2 micrometer. Products with crystal size at the lower end of this range(fine crystal) are favoured in many plastics because of this tone effect i.e. increase in blueness of reflected light with decrease in crystal size. These color/tone differences are relatively small in white applications but are accentuated in colored systems. Failure to achieve good dispersion of titanium pigments in a polymer results in inefficient use of th pigment and a loss of optical and mechanical properties