Plastics Processing

Heat transfer fluids are needed for the polymerization and polycondensation of polyester, nylon processing, and in the production of synthetic fibers, PET molding operations and other plastics processing operations.


Every step in the manufacturing process of synthetic fibers —from polymerization to drawing of synthetic fibers —can benefit from the use of heat transfer fluids. Nylon and various polyesters require high temperatures during processing. Both liquid and vapor phase heat transfer fluids can be utilized, depending on the type of operation being performed.

DOWTHERM™ and SYLTHERM†1 heat transfer fluids are thermally stable when used within their recommended operating temperature ranges; a variety of fluid options are available to help meet specific processing requirements. The fluids can provide the desired level of heating without charring and degradation that can reduce heat transfer efficiency, require frequent fluid addition, shorten fluid life, and result in system downtime for cleanout, maintenance or repairs. Because properly used Dow fluids will not foul heat transfer surfaces, the consistent, even heating required in fiber drawing processes can be maintained.

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Blow molding requires precise and uniform temperature control to help achieve product quality and enhanced physical properties. Since localized heating with electric heating elements often does not provide the precision needed, use of heat transfer fluids to maintain more precise and consistent temperatures has become standard in the industry. Material reservoirs, molding machines and extruders can all be maintained at specific temperatures by circulating heat transfer fluid at a controlled rate. The processing temperature required usually determines which DOWTHERM or SYLTHERM heat transfer fluid is preferred.

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DOWFROST and DOWCAL™ N fluids are widely used by large dairies, other food processors and packaging companies to help cool molds used to produce plastic bottles. Because these fluids remain liquid at lower temperatures than plain water, they cool molds faster, increasing production rates. Faster cooling also allows molding “flash” to be trimmed more quickly and cleanly, further enhancing productivity and improving product quality. DOWTHERM organic fluids are used in resin production.

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