UV Glossary
9-6
Part 1061253B
E 2006 Nordson Corporation
monomers A molecule of relatively low molecular weight and simple structure
capable of combining with itself or other similar molecules to form
polymers.
nanometer (nm) Unit of length equivalent to one billionth of a meter.
negative cooling When the cooling air for the lamp head is drawn from the area
surrounding the substrate being cured and through the lamp head.
Negative cooling provides exhaust for the UV system if it is ducted to
atmosphere. Negative cooling is most often supplied through a
remote cooling fan.
nitrogen blanketing Refer to nitrogen inerting.
nitrogen inerting When the coating or ink is flooded with a nitrogen blanket to prevent
the coating or ink from oxidizing before cure. Nitrogen inertion
reduces oxygen inhibition.
oligomers A low molecular weight resin or polymer used in a radiation curable
coating.
out-of-focus When a lamp head is located further away from the substrate or closer
to the substrate than the focal distance.
oxidizing When the coating or ink reacts with oxygen and slows the
polymerization process of the cure.
oxygen inhibition Oxygen slows the cure response of UV curable coatings. The higher
the ratio of exposed surface area to coating mass, the greater the
impact oxygen has on the coating.
ozone (O
3
) An unstable, colorless gas with a penetrating odor that is generated by
the reaction of short-wave UV light (≈184 nanometers) with air.
ozone-inhibiting
(ozone-free) bulbs
Bulbs where the quartz is manufactured with an additive that prevents
the transmission of UV beneath 200 nm in wavelength. It is the
reaction of short-wave UV light (≈184 nanometers) with air that
produces ozone.
Parts Per Million (PPM) The units of the Threshold Limit Value (TLV) when referring to the
maximum level of a substance that a person should inhale over an
8-hour shift during a 40-hour week without producing an ill effect. Also
refer to Threshold Limit Value.
peak irradiance (peak
power density)
The maximum irradiance measured over a sample period, measured
in joules/cm
2
/sec or watts/cm
2
.
