Heat stabilizers organotin

Another class of organotin heat stabilizers is the sulphur-free estertins or organotin carboxylates like dibutyltin maleate. Estertins work especially well in out-door applications like transparent and translucent double-walled panels for greenhouses, sidings, and window profiles. 

Plasticized polyvinyl chloride Aqueous and food oils Di-2-n ethyl hexyl phthalate plasticizer, organotin heat stabilizer, processing aids, external and internal lubricants Gas chromatography FTIR spectroscopy, atomic absorption spectrometry, differential scanning calorimetry [172]... 

Organotin heat stabilizers Potentrometric tiuation of organotin in polymer extract with standard sodium methoxide in pyridine using antimony and calomel electrodes 95,96... 

Heat stabilizers protect PVC during processing and applications under heat exposition (Pospisil, 1990c). Typical heat stabilizers consist of barium, calcium or zinc soaps of fatty acids (43, R=Cu-C17, M=Ba, Ca, Zn binary salts Ba/Zn or Ca/Zn are mostly used) and various organotin compounds, e.g. dibutyltin maleate (44) or dioctyltin bis(iso-octylthioglycolate) (45) (PospiSil, 1990c). 

Concentration levels of heat stabilizers in various PVC products are in the range 1.5-3.0% for metal soaps and 0.3-2.5 % for organotin stabilizers (Pospfsil, 1990c). Aliphatic (22) or mixed aliphatic/aromatic phosphites (23, 24) are used together with polyols (e.g., pentaerythritol or sorbitol) and acid scavengers as co-stabilizers in PVC (Pospfsil, 1990c). 

Heat stabilizers have preventive and curative functions (Andreas, 1990). As preventive stabilizers, they deplete initiation sites in the PVC backbone by elimination or complexation of reactive chlorine atoms by organotin stabilizers (e.g. 45) according to... 

The curative mechanism of heat stabilizers accounts for a reduction in the rate of formation of polyene sequences -[CH=CH]n- and deactivation of hydroperoxides in PVC (Andreas, 1990). Organotin maleate 44 or thiol 97 released from 45 were reported to stop the growth of polyenes by adding to the C=C bond in PVC. 

Other Plastics Uses. The plasticizer range alcohols have a number of other uses in plastics liexanol and 2-ethylliexanol are used as part of the catalyst system in the polymerization of acrylates, ethylene, and propylene (55) the peroxydicarbonate of 2-ethylliexanol is utilized as a polymerization initiator for vinyl chloride various trialkyl phosphites find usage as heat and light stabilizers for plastics organotin derivatives are used as heat stabilizers for PVC octanol improves the compatibility of calcium carbonate filler in various plastics 2-ethylliexanol is used to make expanded polystyrene beads (56) and acrylate esters serve as pressure sensitive adhesives. 

When an actual "bake" is required in order to produce a high gloss or due to the treatment of some other part of the item coated, the selection of the stabilizer is very difficult. As mentioned earlier, the copolymer may depolymerize before HCl degradation takes place. This limits the selection of the stabilizer. The sulfur-containing organotin type stabilizers appear to be more effective with respect to improving the heat stability of the solution vinyl resin systems. 

Organotin compounds that are salts of alkyltin oxides with carboxylic acids (e.g., dioctyltin dilaurate) are usually called organotin carboxylates. Organotin compounds with at least one tin-sulfur bond (e.g., dioctyltin octylthioglycolates) are generally called organotin mercaptides. The latter are considered to be the most efficient and most universal heat stabilizers. The important products which are on the market have the following structures ... 

Heat stabilizers may be classified as either primary or secondary. Primary heat stabilizers inhibit dehydrochlorination in chlorine-containing polymers and react with any liberated hydrogen chloride to delay further degradation. Mixed metal salts are primary heat stabilizers and form metal chlorides with hydrogen chloride. However, mixed metal salts have a destabilizing effect which results in discolouration of the polymer. This effect is counteracted by the introduction of secondary heat stabilizers such as organophosphites and epoxy compounds. Organotin and lead primary heat stabilizers can be used alone. 

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