CRAYVALLAC® MT

• CRAYVALLAC® MT is a micronised amide modified hydrogenated castor oil rheology modifier for solvent-based and solvent-free coatings.
• CRAYVALLAC® MT is suited to coating systems based on aliphatic hydrocarbons, aromatic hydrocarbons and aromatic hydrocarbon/alcohol blends.
• Compared to the most basic hydrogenated castor oil based rheology modifiers, CRAYVALLAC® MT is more tolerant to stronger solvents.
• The result of this is a lowered risk of problems such as seeding and false-body.

The following table gives processing temperature guidelines for some solvent systems commonly used in coatings:

• Aliphatic hydrocarbons 35 - 75°C (95 - 167°F)
• Aromatic hydrocarbons 30 - 50°C (86 - 122°F)
• Aromatic hydrocarbon/ Alcohol blends 30 - 50°C (86 - 122°F)
• Solvent free epoxy coatings 40 - 60°C (104 - 140°F)

CRAYVALLAC® MT is best incorporated during the pigment dispersion stage using a high-speed disperser operating at a temperature within the recommended guidelines.

• In order to obtain the maximum performance from CRAYVALLAC® MT, the dispersion process should be maintained for a period of 20 – 40 minutes at the recommended temperature. The use of high-speed dispersers is ideal in that they generate both the necessary shear and temperature required for full dispersion and activation.
• The activation process constitutes the conversion of the CRAYVALLAC® MT particles to an interacting network of fibre like particles.
• It is this network that gives rise to the final coating’s shear thinning rheology.
• This shear thinning characteristic provides a very high viscosity under the low shear rates associated with sedimentation, and a low viscosity at the much higher application shear rates. The net result is excellent control of sedimentation combined with ease of application.
• Immediately following application, where low shear conditions again predominate, the coating’s viscosity undergoes a time dependent recovery as the network re- establishes itself. This time dependence is known as thixotropy and enables the final coating to attain very good levelling.
• Activation at too low a temperature, or too high a temperature, or for too short a time, will result in the formation of an inefficient interacting network.
• The use of too high a temperature will result in the network dissolving. Partial dissolving of CRAYVALLAC® MT during coating manufacture manifests itself on cooling in the form of seeding. This is when dissolved material crystallises out in an uncontrolled manner.
• As with all rheology modifiers based on hydrogenated castor oil, coatings prepared using CRAYVALLAC® MT may sometimes develop an excessively high structure, or false body. This results when the hot coating is allowed to cool in the absence of stirring.
• This effect is minimised by cooling the coating with stirring to less than 40°C (104°F) prior to discharge.
• Fortunately, this false-body phenomenon is a temporary effect and can be removed by the application of shear.
• Due to the potential for false-body to occur, care must be taken to ensure that process and quality control tests are not carried out on affected samples.
• This is best achieved by pre-conditioning all samples by mechanical stirring for several minutes prior to testing. In addition to solvent-based coatings applications, CRAYVALLAC® MT has been used successfully in a multitude of other applications such as inks, adhesives, mastics, caulks, sealants, fillers, greases and lubricants.
• Due to the multitude of formulations, processing methods and application conditions used in the field, we strongly recommend that all products containing CRAYVALLAC® MT be tested thoroughly to ensure their suitability for their intended end use.
• In particular, application in poorly ventilated areas, or on hot substrates, or by hot spray, may require additional attention.

• 100% Active
• Imparts shear thinning rheology with thixotropic viscosity
• Recovery
• Very good sag resistance
• Very good anti-settle properties
• Suitable for solvent-free coatings
• Very good recoatability

• Use corrosion- resistant storage tanks and piping.
• Air-operated diaphragm pumps are preferred.
• Avoid temperature extremes.
• Do not freeze; store between 5°- 30°C.
• Under these conditions, the product may be stored for up to 4 years from production date.