One of the most important steps in the manufacturing of emulsion paints and plasters is the dispersing process. During this process the pigments and fillers need to be completely wetted and stabilized against re-agglomeration. Dispersing agents accelerate the grinding process, prevent pigments from flocculation and also prevent a viscosity increase in the finished paint. In aqueous emulsions and plasters the mechanism of electrostatic repulsion stabiles the pigments from re-agglomeration.
Dispersion paints are usually formulated with extenders, particularly the very fine calcium carbonates now available. The dispersion of these extenders in water based systems must be achieved easily with common stirrers and without forming agglomerates or causing a viscosity build up. The usual inorganic dispersants do not solve this problem satisfactorily:
• either because their complexion and deflocculating action are limited by the fineness of the extenders used,
• Or because of their poor temperature stability which causes hydrolysis and limits their efficiency.
Rockacryl DW-30 has been especially developed to overcome these problems. It ensures the complete dispersion of the extenders and the inorganic pigments at high solids contents and in systems with high P.V.C.
|Clear viscose liquid||Appearance|
|Colorless to pale yellow||Color|
|Ammonium salt of polyacrylic acid||Nature|
|30 ± 1||Solid content %|
|300 – 700 m.Pa.s||Viscosity(Brookfield)|
|7 – 8||PH (1:10 solution)|
|Max 12 months||Storage life:|
|Under uniform temperature at 5-25°C||Storage condition|
|According to our best experience, it hasn’t any harmful effect on health||Safety|
Rockacryl DW-30 must be present during pigment and extender dispersion and should, therefore, be added before these products are blended in. The addition level is determined by plotting the graph of the viscosity of the dispersion in water, versus the amount of dispersant added. The level of dispersant corresponding to the minimum viscosity is selected as the addition level. The required amount varies from 0.1% to 0.5% of active ingredients based on the total weight of the pigments and fillers. It is recommended to disperse the pigments and fillers in a pH range of 7.5 to 9.5.
Besides dispersion paints, the main applications for Rockacryl DW-30 are in adhesives and wall paper pastes.
• Liquid product ready to use, easy to handle
• Low level of addition
• High efficiency for dispersion of mineral pigments and extenders, and consequently low grinding time required
• Very good stability of the manufactured products, in particular excellent viscosity stability
• No foaming is encountered with Rockacryl DW-30
Dispersion of natural calcium carbonate into water at 75% solids
(0.1 and 5 μm particle size)
Level of dispersant (active content) needed to obtain a Brookfield viscosity of 2000 m.Pa.s at 20 rpm:
Rockacryl DW-30 0.45%
Usual organic dispersant 0.70%
Inorganic dispersant impossible to obtain
Dispersion into water of CaCO3/Titanium dioxide blend at 80% solids
Titanium dioxide 7.7
Natural CaCO3 (1 to 10μm) 62.3
Natural CaCO3 (0.1 to 5μm) 30.0
Amount of dispersant needed to obtain a Brookfield viscosity of 2000 m.Pa.s at 20 rpm:
Rockacryl DW-30 0.18%
Usual organic dispersant 0.48%
Inorganic dispersant impossible to obtai
طبق دانش و تجربیات فنی ما، اطلاعات فوق صحیح و دقیق میباشند. توصیه میشود قبل از مصرف، اطلاعات فوق در مورد موارد استفاده مختلف بررسی شود.