UV科技-紫外线基本知识

UV Technology

What is UV curing?

ØProcess to cure coatings

ØIn a fraction of a second the coating is converted from liquid to a solid

ØCross linking is a chemical process initiated by UV light

ØCoating can be solvent-free

Reaction mechanism:

What is UV light?

UV light is part of the electromagnetic spectrum:

UVA: 320-400nm, UVB: 280-320nm, UVC: 200-280nm.

Components of a UV formulation:

ØOligomer: Main component of the formulation. Provides main coating characteristics.

ØMonomer: Used to control viscosity and contributes to shrinkage, flexibility, cure speed etc. Also part of crosslinking reaction.

ØPhotoinitiator: Absorbs UV light and initiates the polymerization reaction.

ØPigment

ØAdditive

Chemical types:

There are two chemical types:

Reaction of UV curing process:

UV Spectra

1, Photoiniator absorbs at specific wavelengths

2, Components in the UV formulation also absorb UV light and compete with the photoinitiator

Absorption characteristics of the photoinitiator and coating

Emission spectrum of the UV light

To optimal the curing result the output of the UV bulb must match the photoinitiator absorb characteristics:

A typical UV coating line:

The advantage of UV coating:

1, Environment protection, reduces Voc;

2, Fast curing speed, energy saving, room saving;

3, Increase hardness improves the anti-scratch, chemical resistant property.