Colophony Biological Source
Pinus is the biological source of colophony. It is obtained from the solid residue of the distillation of volatile oil from Oleoresin from Pinus species, such as
- Pinus palustris (long leaf pine)
- P. pinaster
- P. halepensis
- P. massoniana
- P. tabuliformis
- P. carribacea var.,
Its synonyms are: Rosin, yellow resin; Abietic anhydride; colophony resin; amber resin; resin; coloponium.
The genus Pinus is widely found in the United States, China, France, Greece, Italy, India (Himalayan region), New Zealand, Portugal, Pakistan, and Spain. The United States contribute about 80% of the world’s supply of colophony. Other countries producing the resin are China, France, Greece, Honduras, India, Morocco, Poland, Russia, and Spain.
Collection
Colophony is a normal (Physiological) resin of Pinus species, but its amount is increased by injuring the plant. Make a few-foot-long groove or blaze in the bark using a knife. A metal or earthenware cup is attached right below the groove by nails. As the groove increases, the cup is adjusted. The resin is taken out at regular intervals and processed.
Cup and Gutter Method
- This method is used in America, European countries, India, and Pakistan.
- A 60–100 cm long blaze or longitudinal groove is made.
- It is enlarged at intervals for a few years until it is 4 m long.
- The metal or earthenware cups are attached, and one or two strips of galvanised iron are placed above each to direct the flow of oleoresin.
- The cups are moved higher as the grooves are lengthened.
- When the older grooves are exhausted, new grooves are made.
- The cups are emptied regularly, and the oleoresin is sent to the distillery.
- Each tree can be tapped for about 40 years.
Preparation
- The crude oleoresin, which arrived at the distillery in barrels, is mixed with about 20% by weight of turpentine in a heated stainless steel vessel
- It is allowed to stand to separate water and other impurities.
- The diluted oleoresin is transferred to copper or stainless steel stills.
- The turpentine is removed by steam distillation.
- The molten resin is run through wire strainers into barrels to cool it down, and then exported.
- The first batch of resin from the first year will have a lighter colour than that obtained later on.
Characteristics
- Colophony is translucent, hard, shiny, sharp, and pale yellow to amber in colour
- They fracture brittlely at ordinary temperatures
- They burn with smoky flame
- Has a slight turpentine-like odour and taste
- Can melt readily on heating
- Has a density of 1.07–1.09.
- Acid number is not less than 150.
- It is insoluble in water but freely soluble in alcohol, benzene, ether, glacial acetic acid, oils, carbon disulfide, and alkali solutions.
Chemical Constituents
The main chemical constituents in colophony is 90% of resin acids. There are also fatty acids, esters, and resins.
- 90% of the resin contains isometric, alpha, beta and gamma abietic acid.
- 10% of resin contains dehydroabietic acid and dihydroabietic acid.
- Excess pimaric acids are found before distillation. Distillation converts the (-) pimaric acid into abietic acid. However, (+) pimaric acid remains stable.
- Sipinic acid and hydrocarbons are the other chemicals.
Uses of Colophony
- As a stiffening agent in ointments
- As adhesives and plasters.
- Has diuretic properties in veterinary medicine.
- Commercially useful in varnish, ink for printing, soap, cement, sealing wax, floor coverings, plaster, tree wax, fireworks, paper, waterproofing of cardboard, etc.
- Abietic acid has antimicrobial and anti-ulcer properties.
- Used for the preparation of plasters, disinfecting liquids, etc.
References