Tetrapotassium pyrophosphate (TKPP) and potassium tripolyphosphate (KTPP) are used extensively in latex paint formulations to utilize their superior dispersion properties. In latex paints containing zinc oxide, dispersants such as the condensed phosphates are a necessity.

CALGON^®, LOPON^®are powder and liquid products for binding calcium and metal ions, for the dispersion of fillers and pigments, for the production of highly filled interior paints as well as exterior paints.

CALGON^® and LOPON^® Range as Dispersing Agents
 
Usually, the first step in the production of paints based on aqueous polymer dispersions involves the preparation of an aqueous mill base and hence a dispersing process. The tasks of this process are to wet, to physically separate and, finally, to stabilize the individual primary pigment particles in the suspending medium, in this case water. The pigment particles are thereafter present in a homogeneously dispersed from and must not be allowed to re-agglomerate. Generally, the quality of the dispersing process has a direct bearing on the optical and rheological properties of the paint, as well as those properties that affect the paint’s storage stability.

Dispersing agents are used to assist the mechanical process of dispersing solid, insoluble pigments in water. These dispersing agents are mostly polymeric substances which dissociate into ions in aqueous media. The only major factors governing the efficacy of a dispersing agent are the polyanions formed in this process. The part played by the counter-cations is relatively minor.

Owing to the polar nature of the pigment and filler particles (surface-linked hydroxyl groups, adsorbed water molecules), the polyanions are adsorbed on the surface of the solids. The total charge of the surface becomes anionic, thereby resulting in electrostatic stabilization. When polymers with higher molecular weights are used, steric stabilization occurs as well. This mechanism encourages the formation of discrete particles, which repel one another because of their uniform charge. The physical phenomena in the microscopic range manifest themselves macroscopically through a reduction in the viscosity of the suspension. This property is used to determine the quantity of dispersing agents needed in order to stabilize the system.

The dispersing agents most commonly used are polyphosphates and polyacrylates. Please contact us for formulation suggestions and further information.

CALGON®-Polyphosphates

By heating certain orthophosphates to temperatures above 500 °C in a melting furnace, linearly linked structures – so-called polyphosphates – are formed by a condensation reaction.

Sodium polyphosphates

• CALGON^® N (Powder)
• CALGON^® N new
• CALGON^® 322
• CALGON^® 322 new

Potassium phosphate

• CALGON^® TK

For trademark reasons in some countries the label POLYRON or CALFORT is used.

Advantages
1) High capacity for binding Ca- and metal ions
2) Rapid viscosity reduction in disersing process

LOPON as Organic Dispersant

Phosphonate

• LOPON® P
• LOPON® W
• LOPON^® PO

Polyacrylate

- Sodium-Polyacrylate
• LOPON^® LF
• LOPON^® 800
• LOPON^® 890

- Potassium-Polyacrylate

• LOPON 895

- Ammonium-Polyacrylate

• LOPON 885

The LOPON specialities offer following advantages

• High calcium binding properties
• High dispersing effectivity
• Good pigment wetting
• Good leveling
• Excellent water resistance
• Good storage stability
• Excellent scrub resistance

The LOPON organic dispersing specialties are recommended for

• Water based interior paints
• Water based exterior paints
• Varnishes
• Plasters
• Silicate paints
• Silicone Resin Paint
• Pigment Slurries

LOPON P as phosphonate dispersing agent for roof tile paints, silicone resin paints and pigment pastes.

LOPON P offers following advantages

• Excellent lime binding efficiency
• Excellent pigment wetting characteristics for inorganic and organic pigments
• Excellent water softening properties
• Prevention of rub-out