Microcrystalline waxes are hydrocarbon waxes produced from petroleum by means of especially designed extraction and refining procedures. The fine structure of microcrystalline waxes gives rise to their special properties namely their ability to retain oil and their flexibility.
Properties
There are many grades of microcrystalline waxes; their melting points range from 65 ºC to 95 ºC. These waxes can be very flexible or very hard. They are insoluble in water and possess excellent properties as barriers against water vapour. Microcrystalline waxes are chemically almost inert and very stable. Moreover they offer excellent electrical properties. Their main properties are:
- show good miscibility with other types of waxes; with oils of mineral or biological origin; with fats, fatty acids, many types of resin, polyolefines and with natural or synthetic rubber
- are soluble on heating in various types of solvents, for example spirit of turpentine, white spirit, benzene, toluene, xylene and chlorinated hydrocarbons; on cooling the solutions, more or less pasty masses are formed depending on the wax type and its concentration in the mixture
- have the property of modifying the crystallisation of many products so as to produce a finer crystal structure
Standard and plastic types
Microcrystalline waxes are composed entirely of carbon and hydrogen ("hydrocarbons"). Their molecular weights lie between 600 and 900. Their acid and saponification values are zero. The range is divided into two types:
- standard microcrystalline waxes, penetration at 25 ºC : 8-40
- plastic microcrystalline waxes, penetration at 25 ºC : 20-40
Applications
Microcrystalline waxes are applied in the manufacture of the following products:
- packaging materials
- chewing gum
- paints
- printing inks
- lacquers
- creams and ointments
- lipsticks and other cosmetics
- hot melt adhesives
- emulsions
- resins
- rubber
- metal casting waxes
- electrical compositions
- waxes
- waterproofing treatments
- polishes and house-care materials
- rust preventives, etc.