Chlorinated waxes

In the formulation of PVC compounds it is not uncommon to replace some of the plasticiser with an extender, a material that is not in itself a plasticiser but which can be tolerated up to a given concentration by a polymer-true plasticiser system. These materials, such as chlorinated waxes and refinery oils, are generally of lower solubility parameter than the true plasticisers and they do not appear to interact with the polymer. However, where the solubility parameter of a mixture of plasticiser and extender is within unity of that of the polymer the mixture of three components will be compatible. It may be shown that... 

It has already been mentioned in Chapter 5 that plasticisers are often replaced in part by extenders, materials which in themselves are not plasticisers but which can be tolerated up to a given concentration in a polymer-plasticiser system. Refinery oils and chlorinated waxes are widely used in PVC for this purpose with the prime aim of reducing cost although the chlorinated waxes may also be of use as flame retardants (q.v.). 

Chlorinated waxes Diehl oropropane Tetrachl orophthal ic anliydride... 

In a review of incidents involving explosive reactivity of liquid chlorine with various organic auxiliary materials, two involved hydrocarbons. A polypropylene filter element fabricated with zinc oxide filler reacted explosively, rupturing the steel case previously tested to over 300 bar. Zinc chloride derived from the oxide may have initiated the runaway reaction. Hydrocarbon-based diaphragm pump oils or metal-drawing waxes were violently or explosively reactive [8], A violent explosion in a wax chlorination plant may have involved unplanned contact of liquid chlorine with wax or chlorinated wax residues in a steel trap. Corrosion products in the trap may have catalysed the runaway reaction, but hydrogen (also liberated by corrosion in the trap) may also have been involved [9],... 

Antimony trioxide reacts with chlorine, either in the rubber or present due to the addition of chlorinated waxes, to give gases which function by reducing the oxygen supply. The reaction produces dense white fumes that exclude air and extinguish flames. 

The addition of chlorinated waxes will trap free radicals formed during the basic combustion process, by combination with a hydrogen halide, usually HC1. 

Another group of chlorinated hydrocarbons comprises those made from paraffin wax. Major applications are in extreme pressure lubricants and as extenders and plasticizers in surface coatings and in vinyl plastics. The chlorinated waxes were also widely applied in flameproofing cotton fabrics, which led to large consumption by the military. It is believed that current military requirements for flame-resistant fabrics will be met by vinyl sheeting of vinyl-coated textile products, so that the World War II demand for the halogenated waxes will not be repeated. 

While synthetic oil-soluble sulfonates have also been made by reacting high molecular weight olefins or chlorinated wax with selected aromatics and sulfonating the resulting compound, the oil detergent properties of these materials have been reported to be inferior to those made by conventional acid-treating procedures on petroleum distillates. 

The uses for low molecular weight chloroparaffins are familar they include solvents, cleaning agents, fire extinguishing agents, and chemical intermediates. Applications for the chlorinated waxes include plasticizers, cutting oils, additives... 

Chlorinated wax is considered a secondary plasticizer for PVC because it has limited compatibility 11) and low plasticizer efficiency, compared with primary plasticizers such as dioctyl phthalate. It has good permanence properties—for... 

The purity and straight-chain character of the paraffins are reflected in the color of the chlorinated products. Both thermally and photochemically chlorinated derivatives of the n-paraffin mixture were essentially colorless. Gardner scale color values of 1 and <1, respectively, were obtained on samples chlorinated to about the same degree by thermal (44% Cl) and photochemical (42% Cl) procedures. Commercial chlorinated wax has Gardner scale color values of 2 F6 to 4. 

The improved thermal stability of the chlorinated paraffins also reflects the purity of the n-alkanes. The heat stability of PVC plasticized with chlorinated n-paraffin at 177°C. is better than that of similar compounds using commercial chlorinated wax. This is shown in Table I by the color that developed during thermal treatment for samples in which 40% of the dioctyl phthalate was replaced by chlorinated paraffins. (In this example and those that follow, the total plasticizer concentration is constant at 33 / %.) The color development in this test is significant as a measure of the comparative processing conditions that can be employed. 

Extender plasticizers, which are used mainly to reduce cost, consist of chlorinated waxes, petroleum residues, etc. Incorporation of excessive amounts may result in exudation on aging. The chlorinated types decrease flammability. 

Extenders are referred to sometimes as liquid fillers their most common use is in plasticized PVC, where chlorinated waxes used in this way serve also as flame retardants. 

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