Definition - What does Rosin mean?

Rosin is the yellowish to amber, translucent, hard, brittle, fragmented resin left after distilling the oil of turpentine from the crude oleoresin of the pine.

In industry, rosin is chiefly used in:

  • Varnishes and adhesives
  • Soldering compounds
  • Soap
  • Sealing wax
  • Varnish and paint driers
  • Printing inks

Rosin has been applied as a corrosion inhibitor for carbon steel.

Rosin is also known as resin or colophony.

Corrosionpedia explains Rosin

Rosin is a translucent yellowish to dark brown resin derived from the stumps or sap of various pine trees. At room temperature rosin is brittle, but it melts at stove-top temperatures. It is soluble in alcohol, benzene and chloroform. Rosin consists mainly of abietic acid, and combines with caustic alkalis to form salts that are known as rosin soaps. Rosin is very flammable, burning with a smoky flame, so care should be taken when melting it.

In industry, rosin is a flux used in soldering. The lead-tin solder commonly used in electronics has about 1% rosin as a flux core, helping the molten metal flow and making a better connection by reducing the refractory solid oxide layer formed at the surface back to metal.

Rosin is used when corrosion is a concern. For example, the metal in electrical boards is very thin, and any corrosion can effectively destroy the circuit board. Rosin is noncorrosive at room temperature, so any flux left over from the soldering process does not damage the computer or other electronic devices. At high temperatures, just below 361°F (183°C) for lead-tin solders, the rosin becomes highly corrosive and attacks surfaces to remove and lift (flux) oxide away from the part.

A mixture of pitch and rosin is used to make a surface against which glass is polished when making optical components such as lenses. Rosin is added in small quantities to traditional linseed oil and sand gap fillers, used in building work.

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