Anti-static compound

Until fairly recently most plastics were purchased fully compounded in the colour required for moulding or extrusion, but with a view to offering ranges of colours more cheaply and conveniently it is quite usual now for machines to be fed with blends of natural thermoplastic and masterbatch—a convenient wax-like base containing appropriate concentrations of colorant and other additives (such as anti-static agent). The supply of masterbatches has become an important specialized business. 

This material is a white mineral oil compound designed for use in the coning of oils and possesses anti-static properties as well as self-contained emulsifiers for ultimate removing from the processed yarns. 

Quaternary compound. High purity, long chain quaternary ammonium compound used with caustic to improve fabric wicking characteristics, reduce pilling on polyester and to obtain anti-static properties on triacetate fabrics. Used to remove polyvinyl acetate and other resin esters from fabrics. 

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. 

In addition to the straightforward application of conductors and semi-conductors, there are some interesting examples of other uses. Polymers derived from 3,4-ethylenedioxythiophene are produced commercially as anti-static agents and substituted compounds have found particular application in electrochromic devices - substances that change colour on application of an electric current. 

Anti-static agents Rubber compounds Additives in grease Others... 

Properties affected Colour carbon black also has useful anti-static properties, can provide electrical conductivity black pigments also give effective UV screening also used as a reinforcement in rubber compounds (the largest overall use)... 

In compounding for anti-static properties, the easiest solution is to add carbon black, which makes the plastic more or less electrically conductive (but also makes it black). Where feasible it is used, and most conductive compounds are based on carbon black. For most electrical applications, there are two types of compound, related to performance, discussed below. 

Compounds dissipate a surface charge and can be processed by normal thermoplastic methods. Typical applications are boxes and in-plant handling containers for electronic components or chemicals where there is a risk of explosion from a spark. Medical products also increasingly have ESD specification, especially for use in an operating theatre. Packaging products such as flexible films also require some form of anti-static treatment, either by means of an additive, or by using external field generators. 

This will be mainly to offer a range of colours, while only needing to hold stocks of natural material, or to add or boost specific properties, such as UV stability, anti-static properties or flame retardancy. To facilitate in-plant compounding, most suppliers have developed systems that efficiently and reproducibly deliver a controlled package of additives to a compound, using either a specialized concentrate or a masterbatch formulation. 

Eldorado made a deal with U.S. Radium to market some of that firm s products in the Commonwealth. One of these was Undark, a radium-based luminous compound. The arrangement also encompassed compounds used in the manufacture of television and cathode-ray tubes. The biggest seller amor these products was the lonotron, a radioactive anti-static device that used the ability of alpha radiation to ionize air to prevent formation of static electricity. It was employed in industries where flammable vapours or materials could be ignited by sparks from static electricity. Textile and paper mills were major customers, but the lonotron helped in the operation of coating and packaging equipment as well. It enabled manufacturers to increase the speed of their machines while reducing the risk of fire. 

To maintain the performance of plastics, various additives such as plasticizers, antioxidants, anti-static agents and flame retardants are compounded into plastic products. Some of these plastic additives are leached from plastic product waste, and may threaten humans and wildlife. An example is the release of nonylphenols, or endocrine-disrupting chemicals, from plastic tubes that are employed for scientific research. This is described in a chapter entitled Here, There, and Everywhere in a well-known book on endocrine disruption, Our Stolen Future, by Colbom, Dumanoski and Meyers (1996). 

Anti Static S.p.S. Rhone Poulenc, France Quaternary ammonium compounds... 

Proprietary lubricant, anti-static agent Used primarily as an anti-static agent for polyethylene and polypropylene compounds... 

Proprietary Lubricant, Anti-Static Agent An internal lubricant for rigid PVC compounds, providing a good balance of thermal stability, melt flow and optical properties in a variety of systems. 

Anti-protozoa agents are utilized to treat diseases such as coccidiosis, which affects many farm animals, particularly poultry. Coccidiostats include polyether monocar-boxylic acid ionophores and other types of compounds. Polyether monocarboxylic acid ionophores include monesin, narasin, lasalocid, and salinomycin. The most common of these is salinomycin. Nonionophore coccidiostats include dimetridazole and halofunginone. Stanker et al. reviewed immunoassays available for coccidio-static agents. 

The general drawback of the Wessler model is the static nature of the venous thrombus development. To overcome this problem some investigators have developed more dynamic models with reperfusion of the occluded vessel segments after clot development. Depending on the time of test compound administration (pre- or post-thrombus initiation), the effect on thrombus growth and fibrinolysis can be evaluated. Levi et al. (1992) have used this model to assess the effects of a murine monoclonal anti-human PAI-1 antibody and Biemond et al. (1996) compared the effect of thrombin and factor Xa inhibitors with a low molecular weight heparin. 

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