White masterbatches are used particularly to provide white pigmentation to films and plastic pieces. In addition to providing the characteristic white color of cleanliness and hygiene they also provide the necessary opacity or shade so the package contents cannot be seen.

Rutile-type Titanium Dioxide is the main active ingredient used in the manufacturing of White masterbatches. The high refraction index of this pigment provides optimum opacity to the container.

Opacity depends particularly on two important variables: the white pigment contents and the packaging thickness. The higher the pigment contents and the thicker the packaging, the higher opacity obtained. The following graphics show opacity variations according to the masterbatch pigment concentration and to the film thickness.

Some white masterbatches found in the market combine Titanium Dioxide with certain mineral loads that will act as extenders in order to reduce the masterbatch price. The Titanium Dioxide contents of these masterbatches is usually lower which results in lower opacity as well.

You can find white masterbatches with 40% to 70% Titanium Dioxide concentration in the market, some of which may contain up to 30% mineral loads.

As a rule, white masterbatches with high Titanium Dioxide concentrations are suitable for thinner films and high opacity requirements and masterbatches with low Titanium Dioxide concentrations are more commonly used for films over 2 mm thick.

As White masterbatches density is greater than Polyethylene or Polypropylene density a masterbatch seggreation or separation from resin may occur particularly when mixes are prepared for a long period of time or when they are placed in feeding hoppers submitted to vibration. In critical cases it is recommended to work with a lower Titanium Dioxide concentration masterbatch because of its lower density.