Permanent Antistatic Agents

New non-blooming types of antistatic agent have reeently been developed to overcome the deficiencies of the approaches described above. They are generally elassified as permanent antistatic agents because their effect persists, unlike the blooming type, and they do not involve the use of carbon or metallic fillers. 

Permanent antistats do not depend on the relative humidity and they do not lose their effectiveness in a short time. One type is exemplified by the use of polyether-polyamide block copolymers combined with an intrinsically conducting substance, and another class consists of neoalkoxytitanates or zirconates. These compounds form non-blooming, bipolar layers, producing a surface and volume electron-transfer circuit, which produces a permanent antistatic effect. They are independent of atmospheric moisture and compatible with a wide range of polymers, including polyolefins, polyesters, polystyrene and PVC. Inherently conducting polymer additives such as sulfonated polyanilines are also used. They are discussed further in Chapter 5. 

Metallocene additives like cobalt (methyl cyclopentadienyl)2 work in polyolefins by providing a low-energy transfer of electrons between their adjacent aromatic layers, but they have not been widely used so far because of practical disadvantages, including inadequate heat stability. 

---

Hausmann K. Permanent antistatic agent offers long term performance for films and containers. Plastics Addit Compound [trade journal—Elsevier Ltd.] May/ June 2007. 

Among the many deals, only a few may be mentioned here. Arkema and Ciba Specialty Chemicals signed a global cooperation agreement enabling Ciba to distribute Arkema s Pebax permanent antistatic agents. They are polyether block amides intended for use in ABS, polystyrene and PVC. The two companies are also co-operating in research and development in the same area. Ciba has also become the exclusive distributor outside Asia of Kanebo Chemical s silver-based antimicrobial products for polymers. They are said to be effective, safe and heat-resistant to over 200 °C. 

Cross-linked finishes are not permanent in the tme sense of the word however, under optimum conditions the finish can last for the usehil life of the material. Wet abrasion during laundering is probably the principal cause of gradual removal of the finish. In order to retain antistatic protection for extended use, an excess of finish is often appHed The extent of chemical interaction between the durable antistatic agents and the fiber substrates to which they are appHed is not perfectiy understood. Certain oxidizing agents such as hypochlorite bleaches tend to depolymerize and remove some durable antistatic finishes. Some of the durable finishes have also produced undesirable side effects on textile materials, ie, harsh hand, discoloration, and loss of tensile properties. 

Internal antistats are considered permanent antistats. This permanence is based on the concept that most plastic products are disposable, so that the antistat is not required to last long. The antistatic effectiveness of an internal antistat can decrease over time. One study showed large increases in surface resistivity on antistatic bags stored at 71 °C for six months. Antistatic bags stored at room temperature showed only a small increase in surface resistivity (137). Loss of antistatic effectiveness is attributed to the volatility of the antistatic agent. The antistat does not easily wear off the plastic, but it can be removed with solvents and/or repeated wear. 

In contrast to the applications previously described in which alkanesulfonates are used in polymers with a high glass transition temperature (PVC, polystyrene, and ABS), in antistatic-modified polyethylene articles the antistatic agent is able to continue migrating to the surface over a long period of time. Thus, a more permanent antistatic effect is achieved. 

Yuan, M.,Brokken-Zijp,J., and de With, G. 2010. Permanent antistatic phthalocyanine/epoxy nanocomposites— Influence of crosslinking agent, solvent and processing temperature. Eur. Polym. J. 46 869-880. 

Electrical propertymodifying additives 6 Application limitations from migrating antistatic agents Nonmigrating permanent antistats... 

At the extreme end of permanent antistatic polymers are inherendy conductive polymers (ICP), some of which are said to have recently overcome processing problems in their use. ICPs, including polyaniline, polypyrrole, and polythiophene can reduce resistivity well into the ESD or conductive range ( 10 ). Typically "doped" with a reducing or oxidizing agent, the ICP polymer chains provide a direct path for electron conduction at 10 ohms/sq resistivity. However, ICPs can cause a "hard, rapid discharge in use, as can carbon black and conductive fillers discussed below [6-4, 6-20). 

TransparenL permanent, non-blooming and non-hydroscopic polymers with nano-zirconate antistatic agents, technical paper. Kenrich Petrochemicals, Inc. 

The effectiveness of blooming antistatic agents is dependent on the relative humidity, and its effects are neither permanent nor necessarily immediate. If they migrate too quickly, they are unlikely to remain effective for long - perhaps a few hours. If migration is too slow, it could take weeks before they can provide protection. Mixtmes of fast and slow types can be used to overcome this. 

Ideally, an antistatic agent should be permanent. It should not lose its efifeet, as blooming types do, by migrating too quickly to the surface where it could be removed by washing or abrasion. Its action should be independent of the relative humidity, and it should allow the produet to be light coloured or even transparent, which rules out carbon black. The antistatie agent should not rule out food contact applications. The industry has been addressing these problems, and considerable developments have taken place. 

The technique used to achieve permanence with other additives such as antioxidants and plasticisers has often been to increase the molecular weight of the additives. In the ease of antistatic agents, however, high molecular weight versions of conventional antistats require high loadings, and can significantly increase costs. 

Irgastat P from Ciba Specialty Chemicals is an antistatic agent composed of an intrinsically conductive material and a polyamide. It constitutes a permanently static dissipative system and... 

Permanent non-blooming antistatic agents consisting of neoalkoxytitanates and zirconates have been popularised by Kenrich Petrochemicals under the Ken-Stat name. These substances form bipolar surface layers on the smface, allowing polyolefin films to remain clear after long-term ageing. They are also claimed to be effective in several polymer types, including polyesters and styrene polymers. 

Traditional blooming antistatic agents are facing competition from newer types with more permanent antistatic properties and with the advantage that they are independent of the relative humidity. 

Ethylene and propylene glycols and their low polymers with the ability to absorb and retain moisture act as softening, plasticizing, and antistatic agents for hydrophilic textile fibers. Treatment with waxes such as paraffin emulsions impart water repellency to cellulose fabrics, but the effect is not permanent. Silicones impart water repellency to all fabrics. 

Permanent internal antistatic agent for use in polyethylene, polypropylene, polystyrene, ABS, HIPS and SAN resins. Characteristics ... 

Permanent internal antistatic agent for use in high and low density polyethylene, polypropylene and biaxially oriented polypropylene (BOPP) film. 

Anti stats Antistats or antistatic agents are finishes that can be applied to a fabric to aid in the dissipation of static charge buildup on the fibers. Antistats can be applied to the fiber as a temporary finish or added in the spinning bath prior to fiber formation to give a more permanent finish. Chemical crosslinking of an antistat applied to a textile... 

Some Pebax grades are used to enhance the characteristics of other thermoplastics, in particular as antistatic agents, since they naturally disperse electrostatic charges, and as such can be added to a large number of thermoplastic matrices (acrylonitrile-butadiene-styrene (ABS), polystyrene, polyoxy-methylene (POM), polyvinylchloride (PVC), polymethylmethacrylate (PMMA) and polycarbonate (PC)) to impart permanent antistatic properties, whatever the ambient relative moisture or surface friction they may be subjected to. These antistatic compounds are suitable for countless applications in office and electronic equipment (photocopier components, printer components, etc.) as well as in technical packaging,... 

Uses Surfactant, conditioner, antistatic agent for shampoos, permanent waves, shower gels, body lotions, and conditioning rinses, giving smoothness, flexibility, shine, and body to hair... 

---