USES IN PACKAGING

Gas-phase adsorption can also be used when regenerating the adsorbent is not practical. Most of these appHcations are used where the faciHties to effect a regeneration are not justified by the small amount of adsorbent in a single unit. Nonregenerative adsorbents are used in packaging, dual-pane windows, odor removal, and toxic chemical protection. 

Of the estimated 710,000 t consumed in 1990, 25% was used to produce vinyl chloride [75-01-4] monomer (VCM), 14% for vinyl acetate [108-05-4] monomer (VAM), 23% for butanediol, 14% for industrial use, and the balance to produce other products such as acryUc acid, synthetic mbber, chlorinated solvents, and acetylene black. The demand for PVC is expected to decrease as legislation limiting its use in packaging is pending. Consequentiy, VCM consumption will also suffer. 

LDPE is nontoxic, and is commonly used in food packaging (qv) where Food and Dmg Administration requirements, such as 21CFR in the case of thin films, must be met. It is also used in packaging pharmaceuticals and other medical appHcations such as iv bags and tubes. 

Carboxylic Acid Group. Sorbic acid undergoes the normal acid reactions forming salts, esters, amides, and acid chlorides. Industrially, the most important compound is the potassium salt because of stabiUty and high water solubiUty. Sodium sorbate [7757-81-5] (E,E form [42788-83-0]) is less stable and not commercially available. The calcium salt [7492-55-9] which has limited solubiUty, has use in packaging (qv) materials. 

Miscellaneous Uses. Inks used by inspectors to stamp the grade or quaUty on meat must, bylaw, be made from food-grade colors. Dyes used in packaging materials that come in direct contact with a food must also be food-grade or, if not, it must be estabUshed that no part of the colorant used migrates into the food product. Pet foods, too, if colored, must contain only those colorants recognized by the FDA as suitable for the purpose. 

Precoated butyl latex compounds onto fabric can be used for PSAs in foil and paper lamination. These PSAs are also used in packaging and for bonding polyolefins (require adequate formulation). 

Butyl latex can be used in packaging and as a tackifying and flexibilizing additive in higher strength adhesives for adhesion of polyethylene and polypropylene. 

Nozzle mix 30kW-40MW Yes All gases 15 mbar-1.5 mbar <20 1 depends on oil turndown when dual-fuel Normally nonluminous shape depends on burner and register configuration Wide use in packaged burners of all sizes. Common in hot water and steam boilers of all sizes... 

Very popular is plastic cushioning material used in packaging, usually laminated thermoplastic films that incorporate air bubble pockets. 

The production test showed that the epoxy phenolic enamel was the preferred enamel for coating tinplate containers used in packaging irradiation-sterilized ham and beef. The preferred end-sealing compound for the same application was the blend of cured and uncured isobutylene-isoprene copolymer. 

Glassine is a highly processed paper product with some grease resistant properties. When laminated with a suitable type of wax, it gives excellent protection from both moisture and gas transmission. For this reason it is used in packaging dry cereals. 

There are many variants of benzophenone. They often have numbers after the name, a type of shorthand to indicate which variant is in use. The variations change features, such as solubility or the ease and functionality of bonding with plastics used in packaging. For example, ben-zophenone-2 is used in alcohol-based products, while benzophenone-5 is used in water-based products. Benzophenone-6 is used in nail polish, and benzophenone-9 is used in bath and skin-care products. Some examples are shown below. 

It is instructive to consider the sources of plastics waste. Table 11.1 shows the types of plastics and their use in packaging, whilst Table 11.2 shows the proportion of waste classified by end use. This shows how significant packaging is in generating waste, and causing environmental problems. Applications such as furniture and electrical appliances show more acceptable use of polymers, because discard rates are low and lifetimes of the products are generally long. 

The radiation-treated cables find wide applications in control instmmentation of nuclear power reactors, particle accelerators, aviation, and telephone equipments. Usually PE and PVC are radiation cross-linked for production of such cables. The heat shrinkable foils are widely used in packaging, electrical and electronic industries. The radiation cross-linked PE possesses the property of elastic memory which is utilized to produce heat shrinkable products. 

Additives are needed not only to make resins processable and to improve the properties of the moulded product during use. As the scope of plastics has increased, so has the range of additives for better mechanical properties, resistance to heat, light and weathering, flame retardancy, electrical conductivity, etc. The demands of packaging have produced additive systems to aid the efficient production of film, and have developed the general need for additives which are safe for use in packaging and other applications where there is direct contact with food or drink. 

Nylon barrier layers are used in packaging films and blow molded bottles. In these applications, their excellent resistance to oxygen permeation are valued when packaging greasy foods, such as potato crisps (chips), that rapidly turn stale when exposed to oxygen. 

Because polyethylene terephthalate crystallizes slowly, it can readily be produced in its amorphous state. This is especially true when it is used in packaging materials, such as thin films and carbonated drink bottles. The final products exhibit high clarity and directionally balanced properties because they lack crystalline regions. 

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