Cloisite B-RI: Nanocomposite Additive for Halogen-Free Flame Retardants

Product Overview

BYK Additives, together with Cloisite, is introducing a new nanocomposite additive for polymer applications to the market. Cloisite additives consist of organically modified layered magnesium aluminium silicate platelets. The surfaces of the platelets are modified with an organic chemical substance that ensures complete dispersion in the thermoplastic systems they are designed for. Unlike classical layered fillers such as kaolin, talc or mica, the typical thickness of Cloisite is 10–50 times smaller. The completely exfoliated silicate platelets from which Cloisite additives are obtained are only 1 nanometre thick. This special structure of the layers provides an exceptionally high aspect ratio of over 100. The high aspect ratio makes it superior to all other classical layered fillers or short glass fibres. Thanks to the high aspect ratio, the properties of a wide variety of polymer materials are improved in an extraordinary manner. This improvement of properties is achieved with only a very low Cloisite concentration. The density of polymers reinforced with nanocomposite additives is only slightly higher than the density of unfilled polymers. This provides a specific weight advantage, particularly in automotive applications. Cloisite covers a broad range of applications that contribute to the improvement of mechanical and thermal properties. In addition, the barrier properties of thermoplastics and thermosets are also significantly increased. • High heat deflection temperature, • Improved barrier properties, • Improved flame retardant performance. The first commercial success of Cloisite products was achieved in halogen-free flame retardant cable compounds. BYK Additives offers three different product classes for flame retardant applications (see table below). Development began with Cloisite 5 and was followed by the finer ground Cloisite 20 class. Both showed good properties in combination with ATH/MDH flame retardants. With Cloisite SE 3000, BYK Additives is introducing a new generation of modified Cloisite products with better handling and processing properties.  

How Can Cloisite Help with Halogen-Free Flame Retardants?

The industry is seeking more environmentally friendly additives for plastic applications. Brominated flame retardants can be replaced by halogen-free systems such as Al- and Mg-hydroxides. High quantities of these hydroxides are required to pass very strict flammability tests. Excessive loading of these additives can lead to adverse effects on the mechanical or electrical properties of cable insulation. Cloisite products offer an entirely new solution to this problem. By adding very small amounts of Cloisite, the loading of inorganic filler can be significantly reduced. Cloisite acts as a synergist in halogen-free flame retardant compounds. The extremely fine particle size and high aspect ratio of Cloisite enable the formation of a three-dimensional inorganic silicate lamellar network in the polymer (even at very low additive concentrations). During the burning of the cable, this three-dimensional network acts like an insulating material, forming a strong carbon shell. The dripping of the melting component is reduced and the time until burning stops is shortened. The time until ignition of pyrolysis gases is increased. Therefore, flame retardant tests can be passed with significantly lower quantities of hydroxides. • ATH/MDH reduced from 65% to 52.5–55.0%, • Compliance with UL94 V-0 standard achieved by adding 3–5% Cloisite, • Elongation at break increased, • Extrusion speed increased during cable production, • Higher productivity achieved The following diagram shows the elongation at break and melt flow rate of Cloisite-improved compounds compared to a typical formulation. All three compounds are classified as V-0 (3.2 mm/1/8") according to UL 94. Compounds containing 3% Cloisite show an improvement of up to five times in melt flow rate and elongation at break.

BYK Additives Additive Product Range:

• Additives that improve surface slip, levelling and substrate wetting, • Adhesion promoters, • Defoamers and air release agents, • Processing additives, • Rheological additives, • UV absorbers, • Viscosity reducers, • Wax additives, • Wetting and dispersing additives for pigments and fillers.

Application Areas Coatings Industry

• Architectural coatings, • Automotive coatings, • Industrial coatings, • Can coatings, • Coil coatings, • Wood and furniture coatings, • Powder coatings, • Leather finishes, • Protective & Marine.

Plastics Industry

• Ambient cure systems, • PVC Plastisols, • SMC/BMC, • Thermoplastics.

Printing Inks Industry

• Flexographic ink, • Gravure ink, • Inkjet ink, • Screen printing ink, • Offset ink, • Over print varnish.

Adhesives and Sealants

Construction Chemicals, Pigment Concentrates, Raw materials for release agent manufacturing. BYK provides solutions tailored to your needs in many application areas. Compiled by: Cansu Güler / Technical Sales Manager / IMCD