What is FP-Opacity Pigment™?
Our products use commercially available TiO2 pigments and a proprietary process that locks-in an improved state of TiO2 dispersion in a shell of high quality precipitated calcium carbonate.
These white pigment composites have an average particle size of 1 micron with each particle of Opacity Pigment™ containing between 3 and 6 TiO2 particles, each statistically spaced from each other by the optimum distance for scattering of 280nm.
The nature of the “special structure” of the calcium carbonate shell produced means that this product will maximize the light scattering and hence the whiteness and opacity by several mechanisms.
As a white pigment, our Opacity Pigments™ have an inherent light scattering functionality and a refractive index of 1.9, unlike extenders and fillers.
The Opacity Pigments™ are used as simple, weight for weight partial replacements for your existing TiO2. Depending on the application and formulation type, Opacity Pigments™ can normally replace between 5 and 30% of the TiO2 without reducing your product quality or performance.
Why FP-Opacity Pigments™ improve TiO2 efficiency in Coatings
In a given dry system, there will be in the continuous polymer phase, into which TiO2 and extender are dispersed, efficiently yet randomly in the polymer. The TiO2 cannot occupy the same space as the extender and as a result the TiO2 is compressed into the spaces between the extender particles, the random nature of its dispersion meaning that only about 30% of it is at the optimum 280 nm particle spacing for best TiO2 efficiency.
It is well documented that TiO2 is inefficient if too close together, or in lower concentrations, if too far apart.
Since the extenders are similar in refractive index to the polymer, they effectively make “windows” in the film for light to pass through, due to the lack of refraction. While a small amount of extender can be used to replace some of the TiO2 the effectiveness is limited to only a few percentage points before the opacity begins to drop.
By replacing a portion of the TiO2 with FP-Opacity Pigment™, we increase the average distance between TiO2 particles in a crowded system (“dilution effect”), in addition to replacing the volume of TiO2 with TiO2 particles that are optimally spaced. The effect on the statistical particle spacing is clear.
Therefore in effect, and in many plastics and coatings applications, FP-Opacity Pigment™ can be used to replace 10-30% of the TiO2 and not reduce the optics.
Why FP-Opacity Pigments™ improve TiO2 efficiency in Plastics
In a typical plastic system, there will be in the continuous polymer phase, into which TiO2 is dispersed, efficiently yet randomly in the polymer. It is well documented that TiO2 is inefficient in plastics due to the TiO2 particles being too far apart (as a function of the TiO2 concentration), thus allowing light to pass through the “windows” in the film.
Shown opposite, the average TiO2spacing in a 3% TiO2Polyethylene film was found to be 4 to 5 particles apart, with only 4% of the TiO2particles optimally spaced (i.e. 1 particle apart).
By replacing a portion of the TiO2 with the optimally spaced TiO2in FP-550 Opacity Pigment™, we are able to increase the optimally spaced particles by 10% and achieve an improved optical performance.
Therefore in many plastics, FP-Opacity Pigment™ can be used to replace 10-30% of the TiO2 and maintain or improve the optics.
Using a filler (e.g. calcium carbonate) to reduce TiO2levels does not compare with FP-Opacity Pigments™. The filler imparts and excluded volume which the TiO2 cannot occupy, as a result the TiO2 is compressed into the spaces between the filler particles. The concentration effect, while positive for TiO2 spacing is small and rapidly offset by the introduction of “windows” in the film; The filler having a similar refractive index to the polymer and thus allowing light to pass through the film.
Beware of cheap immitations
FP-Pigments have a propriety, patented technology that enables us to produce a truly encapsulated, composite product with TiO2 particles embedded and spaced within a precipitated calcium carbonate shell; we are the only company with this technology. Currently available competitor materials are usually based on simple blends or ‘co-precipitations” of TiO2 and calcium carbonate (or other extenders) and while they claim to be composites they are in effect just random mixtures of loose TiO2 and extender – providing little more than what you could achieve directly by premixing your own TiO2 and extender. (See SEM’pics).
Compared with these competitor blends, FP-Opacity Pigments™ can provide significant improvements in titanium dioxide optimisation and overall cost savings.
Comparing a mixture to FP-460
Both paints contain equivalent levels of TiO2 and precipitated calcium carbonate, in the standard paint they are dry blended in the FP-460 paint they are in the composite form.
Increase in opacity of 2.1 units equating to approximately 25% more scatter.
This model performance shows that the TiO2 used in the FP composite is approximately 25% more efficient than the loose TiO2 used in the paint.