Anti-static additive

It is believed that to avoid any risk of explosion, the electrical conductivity of jet fuel should fall between 50 and 450 pS/m. This level is attained using anti-static additives which are metallic salts (chromium, calcium) added at very low levels on the order of 1 ppm. 

M 07-050/ASTM D 2550/ASTM D 3948) a 70 with anti-static additive... 

To avoid risks of electrostatic charging (sparks, explosions) anti-static additives are sometimes added to a polymer also carbon black may be used (see MT 8.2.1). 

Anti-Static Additive - dissipates static charge in jet fuel. Static charge buildup can result in unwanted ignition of jet fuel/air mixtures. Use is normally not permitted in aviation gasoline except in Canada and Britain. Use is permitted in civil jet fuel and mandatory in military jet fuel. 

In the early stages of the development, the electrical properties of impression roll coverings were rather erratic. In this country, conductivity was imparted by means of conductive, structured carbon black fillers. It turned out that the exact steps in manufacture, such as milling temperature were as important as formulations. The conductivity of compounds made with Buna N was very strain sensitive. In Europe, conductivity was imparted by Anti-static additives. The electrical properties were more predictable, but resistance to wear left much to be desired. The manufacture of suitable roll coverings has been a real challenge to roll manufacturers, and suitable coverings have been available in the last five years on a very consistent basis. New Material which contain conductive polymers (Hercules Inc.) require some warm up before the desired conductivity level is reached, but have very uniform predictable electrical properties and stand up well to the wear and tear of press operations. 

Other surface active ingredients which may be found in plastic materials and suffer loss into product by solution, surface abrasion, etc. include anti-static additives, slip additives, mould release agents, etc. 

Cobalt-phthalocyanine (CPC), used as a anti-static additive for polymeric systems, is synthesised in two reaction steps ... 

The effect of an anti-static additive on the electrical resistivity of a polystyrene foam... 

Polystyrene (PS) foam is only accepted as packaging material for electronic components if the electrical resistivity is low enough to prevent components damage due to electro-static charges. Anti-static additives are added to PS foam batches to reduce static charge and discharge effects to an acceptable level but reliable electrical resistivity values of such foams were not available. Hence, a series of measurements was performed to determine such values. 

A series of four PS foam samples with a density of 20 g/1 was made using the so-called vacuum process. Neostatic HB155 (an alkyl substituted, kationic ammonium salt) was, as the antistatic additive, added in concentrations of respectively 1, 2 and 4 %wt. This anti-static additive was added, dissolved in a constant amount of water, to the expanded PS particles and thoroughly mixed. This mixture was used to press PS foam block samples of 30 x 30 x 5 cm. Subsequently, samples of 9 x 9 x 0.42 cm were cut from these PS foam blocks to measure the electrical surface and volume resistivity. These samples were first stored, however, during six weeks at a temperature of 20 + 1 °C and a relative humidity of 50 %, to reach equilibrium moisture uptake conditions. 

The nummerical results of these measurements are listed in Table 10.1. Figure 10.11 shows resistivity values plotted as a function of the anti-static additive concentration. The addition of this additive certainly works the surface resistivity decreases about four decades and the volume resistivity decreases about eight decades due to the addition of 4 %wt. of Neostatic HB155 anti-static additive. The shape of these curves indicates that addition of higher concentrations of this additive will be hardly effective. 

Resistivity of PS foam as a function of the anti-static additive content... 

Metal Box has developed a copolymer polypropylene container. Poly-can, which has an anti-static additive and is suitable for water-based paints and coating products. Another development is the first bag-in-box paints from Ashwell Paints. A smooth flow is obtained in this system by the use of an open bung and screw top rather than a tap. 

In terms of functions, the emphasis is now on improvement of film processing, anti-static additives, special effect pigments, multi-functional fillers, and stabilizing systems for engineering plastics. Many of the new developments in individual additives are now being offered at the same time in safe, convenient technical masterbatch formulations. 

Antistatic agents are added to plastics before or during processing. In many plastics they migrate continuously to the surface, where a deposit of the material may occur, even if it is frequently removed. Possible interactions with the polymer must be borne in mind when choosing the anti-static additive (such as lubrication, haze, and effects on thermal stability). 

Since the dissipation of the static charge is a function of the liquids conductivity, anti-static additives may be used. These additives do not reduce static generation, but will permit the charge to dissipate more quickly. They should be introduced at the distribution beginning point, and their effectiveness may be reduced by passage through clay filters. 

Anti-static additives E.g., prevent dust build up on consumer items... 

Anti-static additives are capable of modifying the properties of plastics in such a way that they become anti-static, conductive, and/or improve electromagnetic interference shielding (EMI). Carbon fibers, conductive carbon powders, and other electricaUy-conductive materials are used for this purpose. 

An adhesive cannot be selected solely on the basis of bond strength information as other factors such as cure speed, environmental resistance and dispensing method will all influence the final choice. The values given for the shear strength are given to provide a general idea of how each of the nine adhesives performed on the particular material. Different performances will be achieved depending on the fillers, lubricants, colourants and anti-static additives. 

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