Bentone 38 tetraalkyl ammonium hectorite Elementis Rheology Modifiers / Thickeners >> Organoclay >> Hectocrite Acrylics/ Acrylates Epoxy (EP) Polyesters Rubber - Elastomer (Chloroprene, Butyl …) Silicones (Si) PU - Prepolymers Polyvinyl acetate emulsions & derivatives (PVAc…) SEALANT ADHESIVE >> Hot-melt >> Pressure sensitive (HMPSA) ADHESIVE >> Solvent based rheological additive for low to intermediate polarity organic systems BENTONE 38 is an organic derivative of a special smectite. This highly efficient rheological additive is designed for low to intermediate polarity organic systems. Applications Adhesives and mastic compounds Alkyd No hard pigment settling, no sag, no syneresis in thixotropic paints, no flooding Epoxy Ester No settling or sag of the paint Epoxy/Coal Tar Thixotropy, more uniform coat surface Polyacrylic No film cracking; increased film thickness Polyester Increased film thickness and film stability, unpigmented top coats of good clarity Polyurethane Increased film thickness, no settling, no sag Polyvinyl Increased film thickness, no settling, no sag Silicone Increased film thickness, retards flow in baking cycles Incorporation General Incorporation of BENTONE 38 in organic systems, e.g. paints, requires high shear dispersion equipment and the addition of a chemical activator. It is activated in two steps: 1. Dispersion (mechanical breakdown of agglomerates) 2. Gelation (development of the gel structure) There are three basic ways to incorporate BENTONE 38: 1. as a dry powder for in-situ gelation 2. as a pregel of commonly used concentration (5-10% by weight) 3. as a pregel of higher concentration (10-15% weight) adjusted to lower viscosity by addition of a wetting agent I. Addition of BENTONE 38 as a dry powder for in situ gelation: No masterbatching process step is required with this method. The BENTONE 38 powder is added directly to the resin (diluted if need be) and is dispersed in it for 5 min. After this, the pigments are added and dispersed. Then the chemical activator is added. If plastic flow of the mill base is desired, the activator can be added before the pigment. If a wetting agent is to be used, it should be added after the chemical activator and prior to the pigment dispersion. II. Addition of BENTONE 38 as a pregel: The solvent is charged to the mixing tank. BENTONE 38 powder is added and dispersed at high shear force. Then a chemical activator (most suitably methanol or propylene carbonate, see below) is introduced for gelation. For incorporation (e.g. into a paint), begin with the binder solution and stir the pregel into it. Add the pigments and disperse. III. Addition as a pregel containing surfactant: This method is recommended when a pregel of high concentration is required or for postcorrection of the flow properties of a paint. This pregel is prepared in the same way as described under 2. It is advisable to add the surfactant to the solvent prior to introducing and dispersing BENTONE 38. For more details see Rheology Handbook. Suitable dispersion equipment High speed disc impellers (Cowles Dissolver), Ultra-Turrax, pearl-, sand-, ball and three-roll mills Recommended quantities of BENTONE 38 The level depends on the system in which BENTONE 38 is to be used. For house paints and industrial paints typical levels are between 0.2 and 0.5% (dry) BENTONE 38 based on total system weight. In synthetic resins (epoxy, polyester), quantities range between 0.5 and 1.0 %. Summary of Toxicity Data This summary is provided as an overview of more detailed toxicity test results on BENTONE 38. Comprehensive reports detailing the procedure and results of these tests are available upon request. Acute Oral Toxicity (Rats) BENTONE 38 has an acute oral LD50 greater than 20.0 g/kg. Primary Skin Irritation (Rabbits) BENTONE 38 is not primary skin irritant as defined by 16-CFR Hazardous Substances Act, Section 1500.41. Eye Irritation (Rabbits) BENTONE 38 is not ocular irritant as defined by 16-CFR Hazardous Substances Act, Section 1500.42. Highly efficient rheological additive designed for low to intermediate polarity organic systems. Can be used in adhesives and mastic compounds. Use levels: 0.5 - 1.0 % in synthetic resins (epoxy, polyester).