A HIGH-PERFORMANCE FUNCTIONAL EXTENDER CONTAINING LESS THAN 0.1% CRYSTALLINE SILICA

SafSil® is a naturally occurring volcanic glass, classified as a vitreous silica/silicate; it contains less than 0.1% crystalline silica.

SafSil® offers these performance benefits, among others, for coatings and related products:

Alkalinity (pH buffer)

Relatively low specific gravity

Ease of dispersion

Gloss and angular sheen reduction

Abrasion and scrub resistance

Burnish resistance

Sheen uniformity

Touch-up enhancement

Superior deep tone color development

Exterior durability

Inertness (frost resistance)

Acid resistant (ideal for severe industrial atmospheres)

Low soluble salt content-20,500 ohm-cm ASTM D2448

Provides "tooth" in primer formulations

As can be seen in the performance benefits above, SafSil® may find application in a host of coatings systems. Interior flat wall paints are enhanced with the use of SafSil®. Properties such as burnish resistance, angular sheen control and uniformity, along with good touch-up qualities may be achieved. In exterior paints and stains SafSil® contributes to superior tint retention. The inertness of SafSil® renders frost free exterior systems. SafSil® functional extenders are versatile and also find use in floor paints and industrial maintenance formulations such as primers. The minerals low soluble salt content suggests application in anti-corrosive metal primers. SafSil® minerals may also find use in powder coatings.

The slightly lower reflectance value of SafSil® is virtually unnoticed in toned or tinted paints. The undertone of SafSil® has essentially no tint strength. In the development of high brightness white paints SafSil® may be blended with other functional high brightness fillers to increase reflectance values. Viscosities of paints containing SafSil®, at typical use levels, do not appear to be influenced by its slightly higher oil/water demand. As is always the case extender modifications are formulation dependent.

SafSil® is a natural offset to replace silica minerals with high crystalline silica content. Environmentally friendly paints meeting the Leadership in Energy and Environmental Design (LEED) and MPI Green Performance requirements may be made with the material.


The International Agency for Research (IARC) on Cancer has identified crystalline silica as a Group 1 (highest hazard category) human carcinogen by inhalation. OSHA requires products containing more than 0.1% crystalline silica to be labeled as a cancer causing hazard. SafSil® is a versatile mineral which avoids a serious hazard to the workforce. The use of SafSil® eliminates the need for cancer hazard warning labels on product containers.

Among the most highly valued benefits of SafSil® is its minimal crystalline silica content. This virtue provides both plant safety and consumer satisfaction with the absence of a cancer hazard warning. SafSil® is classified merely as a nuisance dust.


Paints formulated with extenders containing 99+% crystalline silica cannot meet today's increasingly stringent demands for the safety of paint makers and paint users. The impact of an all-crystalline silica extender on the crystalline silica content of a common flat latex paint may be calculated by example:

Weight per 100 gallons:	1160 pounds
Crystalline silica extender:	150 pounds

99% crystalline silica content extenders contribute 0.99 x 150 = 148.5 pounds crystalline silica, and the crystalline silica content in the paint is: 148.5÷1160 = 12.8%

Substituting SafSil®, containing <0.1% crystalline silica, at equal volume, the same paint contains a maximum 0.001 x 138 =0.138 pounds crystalline silica, or as a percentage:

( 0.138 ) 1160 = 0.012% maximum

Crystalline silica - about one-eighth the 0.1% level that triggers the hazard labelling requirement.


To accelerate the effects of an already severe Arizona exposure location, a series of acrylic latex white tint base paints were prepared at a "high-stress" pigment volume concentration of 65%, and tinted with phthalo blue dispersion to a medium shade. SafSil® grade CT200 was compared to a #4 nepheline syenite and a #2-3 Hegman crystalline silica. Two coats of paint were brush applied to factory pre-primed hardboard panels. The panels were mounted on racks, equipped with opaque flaps, to mask a top portion of each panel.

CIELAB L* readings were measured at 6-month intervals for 24 months with the results plotted on the following graph. The higher the L* reading, the lighter the color - an indication of fading due to chalking. This summarizes only a portion of the extensive Arizona exterior study. Additional details, including performance at 35% and 50% pigment volume concentrations, are available by request.


In addition to this study, SafSil® has been on exterior exposure in many areas. These exposures along with a long history of use in commercial paints and stains verify the materials value. Overall results are promising, especially in regards to tint retention and frost resistance. Exterior properties related to film integrity, such as grain cracking and flaking, appear comparable to other "workhorse" extender pigments.


FORMULATING WITH SafSil®

SafSil® may be used in both water and solvent-based paints. The material is easy to disperse and may be post added to finished batches to control sheen or gloss. Although not quite as efficacious as diatomaceous earth for post addition, encouraging results have been obtained.

The recommended starting point for reformulating toned or tinted paints is to substitute SafSil® on an equal volume basis for the present extenders. It is very important to remember SafSil® has a relatively low specific gravity. In most cases fewer pounds are required. SafSil® may be blended with other minerals to achieve desired optics. In many cases SafSil® can be the sole functional filler but there are times the desired film properties may be enhanced with blending. The blue/grey undertone of SafSil® is generally masked by toners or colorant. Very light pastel color system off-whites have been produced with SafSil® contained paints.

In reformulating higher reflectance paints, blending with other extenders has been beneficial to maintain optics. Reducing SafSil® level and blending with other minerals has been successful as a means of mirroring the optical properties of crystalline silica extenders. By proper choice of mineral type, shape, and particle size, ideal results may be achieved.

Deep and neutral bases, along with darker factory colors, are a natural for the use of SafSil®. The refractive index of SafSil® is very similar to that of resin which transfers to excellent film clarity. Greater color development (intensity) is achieved with the use of SafSil®.

The above information is only a guide for using SafSil® in coatings applications. To learn more call on us to see how SafSil® may be used to enhance your formulations. The CR Minerals laboratory is available to help.

Contact CR Minerals Company, LLC today to find out how our SafSil® can enhance your products.