Pitch (resin)

Source: Wikipedia, the free encyclopedia.

Natural bitumen pitch, from the tar pit above the McKittrick Oil Field, Kern County, California

Pitch is a

viscoelastic polymer which can be natural or manufactured, derived from petroleum, coal tar,[1] or plants. Pitch produced from petroleum may be called bitumen or asphalt, while plant-derived pitch, a resin, is known as rosin in its solid form. Tar is sometimes used interchangeably with pitch, but generally refers to a more liquid substance derived from coal production, including coal tar, or from plants, as in pine tar.[2]

Uses

Bucket of pitch for use on ships

Pitch, a traditional

waterproofing wooden containers, and making torches. Petroleum-derived pitch is black in colour, hence the adjectival phrase, "pitch-black".[3]

The

Jewelers' rouge
) or cerium oxide. The surface to be polished is pressed into the pitch, then rubbed against the surface so formed. The ability of pitch to flow, albeit slowly, keeps it in constant uniform contact with the optical surface.

Chasers pitch
is a combination of pitch and other substances, used in jewelry making.

Viscoelastic properties

The pitch shown in this University of Queensland pitch drop experiment has a viscosity approximately 230 billion times that of water.

Naturally occurring

Trinity College in Ireland in 1944. Over the years, the pitch had produced several drops, but none had been recorded. On July 11, 2013, scientists at Trinity College caught pitch dripping from a funnel on camera for the first time.[6]

Winchester College has a 'pitch glacier' demonstration which has been running since 21 July 1906, but does not have records of regular measurements.[7]

Production

The heating (

birch-tar, a particularly fine tar. The terms tar and pitch are often used interchangeably. However, pitch is considered more solid, while tar is more liquid. Traditionally, pitch that was used for waterproofing buckets, barrels and ships was drawn from pine. It is used to make Cutler's resin
.

A 10th-century redaction of an earlier Greek Byzantine agricultural work brings down the ancient method of applying pitch to ceramic wine casks:

[A wood-based pitch]

sal ammoniac, six drams of manna.[note 4] Thus, having pounded them and boiled them together, they sprinkle eight ounces (uncia)[note 5] of well-ground fenugreek over them and they pitch the cask with them when they are well mixed.[8]

The

ceramic ware was pitched, both inside and out, immediately while they were removed from the kiln and still hot.[9]

Literary references

The ability of pitch to contaminate those in contact with it is mentioned by Dogberry, a character in Shakespeare's Much Ado About Nothing,[10] and the same point is made in a speech by Falstaff in Henry IV, Part 1,[11] who refers to "ancient writers" who have made this observation. The Jewish deuterocanonical Book of Sirach states that "whoever touches pitch gets dirty, and whoever associates with a proud person becomes like him".[12][13]

See also

Notes

  1. lentisk and from pine, and was first washed in a lixivium of ashes. (Geoponika, vol. 1, p. 202. For an extraction method, see Dry distillation#Wood
    .
  2. .
  3. ^ One Attic Greek drachma was a weight of about 4.37 grams; eight drams therefore being the equivalent of 35 g. (1.2 ounces).
  4. plant sap
    .
  5. ^ The Attic uncia was equivalent in weight to about 27.4 grams. Eight ounces would therefore be the equivalent of 219 grams (7.7 UK ounces).

References

  1. ^ "Coal-Tar Pitch, High Temperature" (PDF). Archived from the original (PDF) on May 5, 2021. Retrieved June 9, 2014.
  2. ^ "CPC Definition - C10C Working-up Pitch, Asphalt, Bitumen, Tar; Pyroligneous Acid". Classification Resources. United States Patent and Trademark Office. November 2016. Retrieved August 12, 2023.
  3. ^ Oxford English Dictionary "pitch, n.1", phrases P1
  4. ^ "The Pitch Drop Experiment". University of Queensland.
  5. ^ Biever, Celeste; Grossman, Lisa (April 17, 2014). "Longest experiment sees pitch drop after 84-year wait". New Scientist. Retrieved June 23, 2014.
  6. ^ "Trinity College experiment succeeds after 69 years". RTÉ News. July 24, 2013. Retrieved June 23, 2014.
  7. .
  8. ^ Geoponika - Agricultural Pursuits. Vol. 1. Translated by Owen, T. London: University of Oxford. 1805. pp. 200–201.
  9. ^ Geoponika - Agricultural Pursuits. Vol. 1. Translated by Owen, T. London: University of Oxford. 1805. pp. 198.
  10. ^ Shakespeare, W., Much Ado About Nothing, Act III, Scene III, line 61
  11. ^ Shakespeare, W., Henry IV, Part 1, Act II, Scene IV, line 460
  12. ^ Sirach 13:1
  13. ^ Collins, J. J. (2001). Barton, J.; Muddiman, J. (eds.). 44. Ecclesiasticus, or The Wisdom of Jesus Son of Sirach. p. 677. {{cite book}}: |work= ignored (help)

External links