Heat stabilizers legislation

Emission control legislation is providing challenges and opportunities for plastics. Emission control canisters first appeared as heat stabilized unfilled... 

Fluorochlorinated hydrocarbons have many of the properties of the ideal blowing agent. They are nonflammable, are nontoxic, and have high heat stability. Monofluorotrichloromethane (Freon 11) and 1,2,2-trifluorotrichloro-ethane (Freon 113) are liquid at ambient temperature and they are used in the production of rigid and flexible foams of polyurethanes, PVC, and so on. But they have a negative effect on the atmospheric ozone layer that protects the surface of the earth from short-wavelength radiations from the sun, and for this reason, their use is limited by legislation in many countries. 

Heat treatment by immersion of the timber in hot oil, thus excluding air during treatment, has also been developed for the market. Rapeseed oil, or in some cases linseed oil and oil-based resins, have been used to impregnate the timber and provide a rapid thermal transfer to the wood, while excluding oxygen. The thermally treated timber market has benefited from interest not only in improved dimensional stability, but also the improved resistance to biodegradation seen in these timbers (Welzbacher and Rapp, 2002). This area is set to expand as traditional CCA preservatives are phased out due to recent legislation. 

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