Wax is the name applied originally to
naturally occurring esters of fatty acids and certain alcohols,
but now applied to both natural and manufactured products resembling
these esters.
Lube oil production is the source
of petroleum wax. Only a small percent of crude oil gets produced
into lube oil. Of that, only a small percent is wax. Oil is composed
of pure hydrocarbons. Wax is defined as those hydrocarbons with
carbon chains that number from about C10
to C50. The general difference between mineral
oil and wax is if it's solid at ambient temperature, it's a wax,
if it's liquid, it's oil with a certain pour point.
Petroleum waxes typically range
from C10H38 to C50H102; paraffins going to C33H68
followed by micros and petrolatums. Petroleum wax has the generic
formula CnH2n+2.
Paraffins, microcrystallines and petrolatums are all separated from crude petroleum. Paraffin can be fully refined to contain less than 0.5% oil. It is filtered
to white and is FDA approved. Because of paraffin's superior
burning and water vapor barrier qualities, it is used primarily
in the candle, packaging and building board industries among
many other markets.
Microcrystalline
waxes have better
adhesive and elastic qualities and are used extensively in hot
melt adhesives as well as in the packaging, printing ink and
many other industries. Microcrystalline
wax is refined from petrolatum,
which comes from bright stock oil. It typically contains 41-50
carbon atoms.
Petrolatums are often referred
to as mineral jellies. Mineral jelly is an amorphous mixture
of microcrystalline wax, mineral oil and paraffin
wax. Straight
unblended petrolatums are a by-product of bright stock oil, the
heaviest viscosity lube oil, and are mostly used as feedstock
for refining microcrystalline wax.
Though petroleum waxes are not
referred to as "natural", they are derived from the
decomposition of organic matter and contain 15% hydrogen and
85% carbon.
Synthetic waxes are primarily derived from natural gas or ethylene.
Polyethylene (PE) waxes are made
from ethylene produced from natural gas or by cracking petroleum
naptha. Ethylene is then polymerized to produce waxes with various
melt points, hardnesses and densities. Polyethylene molecular
weights range from 500 to 3000 gms/mole. Oxidized PEs are readily
emulsifiable, whereas non-oxidized PEs largely are not. High-density
polyethylenes (HDPE) have a great deal of crystallinity and their
molecules are tightly packed. Melt points range from 85°C
to 141°C, and they are used in paints, textiles, coatings
and polishes. Low-density polyethylenes (LDPE) display more toughness
and exhibit better crystal formations. Densities are from 0.90
to 0.94 GMs/ml, and melt points range from 30°C to 141°C.
LDPEs are used to improve mar and abrasion resistance, lubricity,
slip and anti-blocking.
Natural waxes are those from
plants, insects and animals. Plant waxes occur on the exposed
surfaces of many plants, protecting the plant against the excessive
loss or gain of water. Beeswax is a substance secreted by the
worker honey bee used for the construction of their honeycomb.
Palm waxes and soy waxes have become increasingly popular for production of "all natural" candles. Beeswax is not just one material, but a huge complex mixture
of different long chain molecules. Typical animal waxes are lanolin,
or wool grease, and ambergris, a wax produced in the intestines
of sperm whales and used in making perfumes.
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About Wax
