Photoinitiators

Spectra Group means specialty photoinitiators. Unlike most companies who may offer off-the-shelf standard solutions, we will work with you to formulate a tailor-made photoinitiator package to fit your unique application and light source.

 

Photoinitiators

Photoinitiators are chemical compounds used to generate reaction intermediates after the absorption of light that, in the presence of specific small molecule monomers, produce solids from liquids. A photoinitiator is a chemical compound that when exposed to light produces reaction intermediates that cause polymerization.

• Type I photoinitiators produce reactive intermediates directly after light absorption
• Type II photoinitiators require a second compound, a so-called co-initiator, to produce such intermediates 

As the leader in the development of photochemical products, the scientists at Spectra Group have pioneered the H-Nu photoinitiator line. H-Nu photoinitiators are capable of curing (harden) resins of two general kinds: 
• acrylates and methacrylates, cured by free radical processes
• epoxides, cured by cationic processes 

Spectra Group offers a patented line of unique Type II UV/visible light photoinitiators, covering the panchromatic UVA and visible spectrum (H-Nu 470, H-Nu 535, H-Nu 635). Pdf links to datasheets

• Acrylate and methacrylate polymerizations (free-radical) initiated by H-Nu 470, H-Nu 535 and H-Nu 635 generally require partners such as amine and iodonium salt co-initiators pdf links to datasheets
• Epoxides (cationic) polymerizations generally are carried out, in combination with iodonium salt co-initiators (H-Nu 470 and H-Nu 535 cationic). Further improvement in polymerization efficiency is possible by the use of proprietary accelerators. pdf link to datasheet
Benefits of the visible light H-Nu photoinitiator series in photopolymerization processes

• High Absorptivity - low concentrations needed
• Speed of Cure - moderate to fast (depending on formulation)
• Better light utilization and reduced levels of UV photoinitiators normally required – by adding H-Nu photoinitiators to an existing UV formulation
• H-Nu photoinitiators can provide a thick cured coating after one pass - saving time and energy
• Capable of significant depth of cure – > 1 inch or more movie clip embed
• Enhanced adhesion/depth of cure of pigmented formulations 
• Cure through UV opaque, pigmented, colored substrates (i.e. red plastic). 
• Photoinitiator bleaching - pale or no residual color 
• Bleaching/Color change indicator of cure (exposure) with visible light (UV)


Spectra Group offers a patented line of unique Type II UV/visible light photoinitiators, covering the panchromatic UVA and visible spectrum (H-Nu 470, H-Nu 535, H-Nu 635).

  • Acrylate and methacrylate polymerizations (free-radical) generally require partners such as amine and iodonium salt co-initiators
  • Epoxides (cationic) polymerizations generally are carried out, in combination with iodonium salt co-initiators (H-Nu 470 and H-Nu 535 cationic).

At Spectra Group, we are pleased to offer photoinitiator kits and combinations to fit a variety of application needs.

Benefits of the H-Nu series in Photopolymerization


  • High Absorptivity - low concentrations needed
  • Speed of Cure - moderate to fast (depending on formulation)
  • Better light utilization and reduced levels of UV photoinitiators normally required – by adding H-Nu photoinitiators to an existing UV formulation
  • H-Nu photoinitiators can provide a thick cured coating after one pass - saving time and energy
  • Capable of significant depth of cure – > 1 inch or more
  • Enhanced adhesion/depth of cure of pigmented formulations 
  • Cure through UV opaque, pigmented, colored substrates (i.e. red plastic). 
  • Photoinitiator bleaching - pale or no residual color 
  • Bleaching/Color change indicator of cure (exposure) with visible light (UV)

H-Nu Photoinitiators Recent Innovations

• Further extensions of the H-Nu photoinitiator line to provide cure with red and infra-red (IR) light sources (H-Nu-Blue and IR) pdf link to datasheet
• Photoinitiators to provide tack-free cure (acrylates) in UVA/visible light range and capable of sensitizing both iodonium and sulfonium salts in UVA/visible range (H-Nu 470X) pdf link to datasheet
• Developed liquid blends for some H-Nu photoinitiators to provide for ease of addition and incorporation as well as the curing range extension to cover UV/visible range (H-Nu 400 IL, H-Nu 470 IL, H-Nu 470 LT) pdf link to datasheets
• Targeted liquid blends to match and optimize surface cure with UVA LED light sources H-Nu 470 LT) pdf link to datasheet
• Improved efficiency of UV and visible light cure (photosensitization) of iodonium salts to cure epoxides (e.g. Cycloaliphatic, Bisphenol A, Novolacs, and others) through the use of proprietary liquid blends and accelerators (H-Nu 390 and H-Nu 390HI) pdf links to datasheets
• Developed antimony-free (H-Nu 390) and both antimony- and benzene-free (H-Nu 390HI) liquid blend cationic photoinitiators pdf links to datasheets
• Developed liquid blends for visible light cure of water-based acrylate monomers and dispersions.
Download MSDS:
All pdf links are in the folder under appropriate names
 
At Spectra Group, we are pleased to offer photoinitiator samples as testing kits, to include all necessary co-initiators and co-solvents. The purpose of having everything in a kit is that you can quickly test your concept to see if our materials may be working for you.

 

For additional information or to order, please call us at (419) 837-9783 or
e-mail us at info@sglinc.com