Non-Lead Stabilizers

Composition Zinc Free Tin Synergist Appearance Fine, light colored powder 

Low cost costabilizer for use with organotin atabilizers. Nonlubricating, non-toxic and easily dispersed. Effective with all types of tin stabilizers. Primary applications Rigid PVC siding, profile, pipe and molded fittings. Also effective in flexible PVC applications when combined with an organotin stabilizer. 

Composition Coated Acid Absorber Appearance Fine, light colored powder Specific Gravity 2.10-2.15 % Retained (325 Mesh) 0.5% max 

Costabilizer for use with lead stabilizers specifically to improve stability in the presence of destabilizing flame retardant and smoke suppressant additives. Primary applications Plenum cable jackets and related constructions. 

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Kaseler, T.G., Non-lead stabilizer systems for PVC wire and cable extrusion (An Update), J. Vinyl. Addit. Tech., 1993, 15(4), 196-201. 

Mizuno, K.M., Hirukawa, H., Kawasaki, O., Noguchi, H., and Suzuki, O., Development of Non-Lead Stabilized PVC Compounds for Insulated Wires and Cables, Furukawa Review, 1999, 18, 111-118. 

Non-Lead PVC Stabilizers Closiag Performance Gap ia Wine," Plastics Technology Maga ne, 35—36 (1993). 

In all of these compounds solvolysis will lead to a tertiary ion. The series [10], [13], [11] clearly indicates the strain argument, and one may note that the difference in rates between [1] and [11] corresponds to an energy difference of only 1 1 kcal mole . The data do not prove that non-classical stabilization of the transition state in [1] and [12] is not partly responsible for the rate differences but rather suggests that relief of striiin could account for the results. Other factors, particularly differential solvation of the ground state and transition state and the possibility that solvolysis may not be of a limiting type but involve reaction with solvent, may also play a role but are difficult to evaluate. In any case the rate of solvolysis of exo-compounds does not appear to be unusually rapid when viewed in this light. 

Risk reduction is a world wide problem and of course a concern to the field of PVC stabilisers. The replacement of lead stabilisers in wire and cable applications is demonstrated. Newly developed non-lead stabilisers (RUP-series) are shown to offer excellent heat stability, electrical and mechanical properties compared with traditional wire and cable formulations. The overall processability is shown with experimental and actual results. The gradual increase in use of ADKs and other non-lead stabilisers in the USA and Japan demonstrates industry s concern for the public demand in saving the environment without direct laws banning the use of lead. JAPAN... 

It appears to hold quite generally that the polarity of monomer or macroions is more important than their resonance stabilizations. The reverse is true for free radical copolymerizations. Since cations and anions exhibit opposed polarities (electronegativities), an r > re in cationic copolymerizations lead to an ta re in anionic copolymerizations, and vice versa (Table 22-15). In most ionic copolymerization cases, one copolymerization parameter is always greater than unity and the other is less than unity (Tables 22-15 through 22-17). Thus, ionic copolymerizations cannot be carried out azeotropically. The product mostly has a value of about unity for the ionic copolymerization of two resonance-stabilized monomers or non-resonance-stabilized monomers that is, more or less ideal nonazeotropic copolymerizations occur. On the other hand, ionic polymerization of a resonance-stabilized monomer with a non-resonance-stabilized monomer often yields rA B values that are much greater than unity. In such cases, an accentuated tendency toward block polymerization is expected and observed. 

Plasticizers containing epoxy linkages such as epoxidized soy bean oil or synergistic compounds such as dibasic lead phthalate and dibasic lead phosphite are also used to enhance heat stability. Non-lead-containing heat stabilizers are currently being developed. Other ingredients such as color pigments and fillers are added to the formulation for the desired coloration and cost reduction, respectively. 

Low cost, non-toxic slightly lubricating calcium/zinc stabilizer with the effectiveness of a lead stabilizer. Does not require ESO. Epoxidized oils are not necessary. Primary applications Cable jackets and other filled compounds. General purpose and flexible PVC compounds. Can also be used as a booster for liquid stabilizers. 

PVC is a substantially amorphous, thermoplastic material which does not exhibit a sharp melting point. With a density of approximately 1.4gcm-3 (0.81 oz/cu.in.) the material (solid, non-filled material) will sink in both water and in saturated, magnesium chloride. The density of commercial compounds may range from 1.34 to 1.45gcm-3 (0.78 to 0.84 oz/cu.in.). The natural color of the material is clear when it is unfilled and stabilized with appropriate stabilizers, for example, tin stabilizers. If the material is stabilized with lead stabilizers, and /or filled, then the natural color is usually an off-white. In either case this means that a wide color range is possible. Many compounds have a hardness, on the Shore D scale, of about 80 and a Vicat softening point (SON) from 65 to 90° C (149 to 194° F). 

On the other hand, not only initial colour but colour change (discolouration) of the resin under UV light and heat is important. Colour retention of a resin is related to the chemical stability and increases as the degree of non-aromatic conjugated unsaturation of the resin molecule decreases. Thus, for rosins a high level of abietic-type resin acids lead to relatively unstable resins. Hydrogenation and disproportionation as well as esterification provide improved stability and colour retention to rosins. 

Chemical Reactivity - Reactivity with Water Dissolves to form an alkaline solution. The reaction is non-violent Reactivity with Common Materials Forms explosion-sensitive materials with some metals such as lead, silver, mercury, and copper Stability During Transport Stable but must not be in contact with acids Neutralizing Agents for Acids and Caustics Not pertinent Polymerization Not pertinent Inhibitor of Polymerization Not pertinent. 

If 5v //v /coex is not small, the simple description Eq. (14) in terms of bulk and surface terms no longer holds. But one can find AF from Eq. (5) by looking for a marginally stable non-uniform spherically symmetric solution v /(p) which leads to an extremum of Eq. (5) and satisfies the boundary condition v /(p oo) = v(/ . Near the spinodal curve i = v /sp = Vcoex /a/3 (at this stability limit of the metastable states both and S(0) diverge) one finds "... 

A special case of the internal stabilization of a cationic chain end is the intramolecular solvation of the cationic centre. This can proceed with the assistance of suitable substituents at the polymeric backbone which possess donor ability (for instance methoxy groups 109)). This stabilization can lead to an increase in molecular weight and to a decrease in non-uniformity of the products. The two effects named above were obtained during the transition from vinyl ethers U0) to the cis-l,2-dimethoxy ethylene (DME)1U). An intramolecular stabilization is discussed for the case of vinyl ether polymerization by assuming a six-membered cyclic oxonium ion 2) as well as for the case of cationic polymerization of oxygen heterocycles112). Contrary to normal vinyl ethers, DME can form 5- and 7-membe red cyclic intermediates beside 6-membered ringsIl2). 

Non-Kolbe electrolysis may lead to a large product spectrum, especially when there are equilibrating cations of about equal energy involved. However, in cases where the further reaction path leads to a particularly stabilized carbocation and either elimination or solvolysis can be favored, then non-Kolbe electrolysis can become an effi-yient synthetic method. This is demonstrated in the following chapters. 

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