Paraffin wax
Contents
Description
Paraffin wax is the most widely used commercial wax. It is mainly derived from the high-boiling fractions of petroleum. It is commonly sold in slabs or blocks which exhibit crystallinity and various degrees of translucency. There is often a difference in melting point between the outside and inside of a slab because of nonhomogeneity. The crude paraffin waxes, containing varying amounts of volatile ingredients, are odorous and greasy. The refined grades are tasteless, odorless, harder and less greasy[1].
Refined Paraffin Wax
A refined mixture of associated solid paraffin hydrocarbons or paraffins is commonly designated as "paraffin wax". The word "paraffin" appears to be a French derivative of the Latin parum, meaning "little", and affinis, meaning "affinity"; in other words, a chemical inactive substance. The high-melting grades are customarily produced free form impurities and are referred to as "fully refined paraffin waxes" or by the simple designation or English term "paraffines"; for example, Asiatic paraffines are said to contain paraffins in the range of C17 to C34[2].
Fully Refined Paraffin Wax
The term "fully refined" is given to paraffin waxes which are water white, free from more than a mere trace of oil, odorless and tasteless, and hard or firm in consistency. The oil plus moisture content should be well within the allowable optimum of 0.5 per cent. Fully refined paraffin wax has a friable, coarse, fibrous crystalline structure which is translucent to opaque white in appearance, particularly noticeable when a slab of the wax is broken. Microscopically its structure when crystallized from a solvent shows more or less circular or ovan aggregates or platelets of cells; the fibrous caracteristic in large masses appears to be due to superimposed aggregates of platelets[3].
Physical Tests on Paraffin Waxes
Some of the more important physical tests on paraffin waxes include:
- 1. Tensile strength, of the force necessary to pull the wax apart.
- 2. Durometer hardness, or the maximum force which may be applied to a small plunger in a wax cake without forcing it further.
- 3. Consistency, or force necessary to push a plunger into wax at a uniform rate, which is akin to viscosity.
- 4. Flexibility, as determined by a bending test which measures force necessary to bend a plate of wax, and the angle to which it may be bent without cracking.
Properties
| Melting Point (ASTM) | 122 - 124 ºF (50 - 51 ºC) |
| Color (Saybolt) | 25 - 30 |
| Flash Point | 395 ºF (202 ºC) |
| Penetration at 32 ºF (0 ºC) | 16 |
| Penetration at 77 ºF (25 ºC) | 22 |
| Penetration at 115 ºF (46 ºC) | 221 |
| Saponification Number | 0 |
| Acid Number | 0 |
| Viscosity at 212 ºF (100 ºC) | 39 |
| Structure | Crystalline |
| Specific Gravity | 0.880 - 0.915 |
Solubility
Soluble in: benzol, ether, chloroform, carbon disulfide, carbon tetrachloride, turpentine, petroleum, fixed oils. Insoluble in: water, cold alcohol[6].
Uses
Candles; waterproofing; sealing; lubricating; food; plant; fruit and vegetable protection; paper; polishes; cosmetics; crayons; pharmaceutical ointments and salves; electrical insulation, etc. [7]
References
- ↑ Bennett, H., Commercial Waxes, Second edition, p. 17
- ↑ Warth, A. H.; The Chemistry and Technology of Waxes. Reinhold Publishing Corporation. Second Edition, p. 401
- ↑ Warth, A. H.; The Chemistry and Technology of Waxes. Reinhold Publishing Corporation. Second Edition, p. 401
- ↑ Warth, A. H.; The Chemistry and Technology of Waxes. Reinhold Publishing Corporation. Second Edition, p. 402
- ↑ Bennett, H., Commercial Waxes, Second edition, p. 18
- ↑ Bennett, H., Commercial Waxes, Second edition, p. 18
- ↑ Bennett, H., Commercial Waxes, Second edition, p. 18