Quick answer: For practical formulation work, photoinitiator screening starts with the light source and film build, then checks yellowing, adhesion, and cure completeness under real production conditions.
UV gravure ink and reference formula
Gravure printing ink viscosity is very small, usually in the range of 20-300mPa-s, to ensure that the ink has good transfer performance, and get excellent print quality. Gravure printing can be used in a wide range of applications, such as paper, film, aluminum foil, etc., and the printing speed is fast (generally 100-300m/min). Due to the thick ink layer of gravure ink, the content of pigment in the ink is relatively low, generally at 6% to 9%.
UV gravure printing ink is close to UV flexo printing ink in formulation design, using low viscosity, fast-curing oligomers and active diluents. In practice, Photoinitiator 819 is often reviewed for through-cure, while ACMO Monomer helps balance reactivity, flexibility, and viscosity; see section 3.5 UV flexo printing ink in Table 3-38, Table 3-39 and Table 3-4, and the selection of photoinitiators in “3.4 UV Offset Printing Ink”.
(1) UV Gravure Ink Reference Formula
Polyester tetraacrylate (EB657) 30.0
Styrene-maleic anhydride copolymer (SMA1440F) 10.0
(EO)4(PET)4A (SR494) 17.0
819 4.9
Blue pigment (LGLP) 5.0
Talc (D2002) 20.1
Brazilian carnauba wax 3.0
Surfactant 4.0
Sulfonated castor oil 2.0
Dibutyl sebacate 3.0
UV stabilizer 1.0
(2) UV red gravure ink reference formula
Hexafunctionality PUA 3
Difunctionality PEA 5
DTMPTA 18
PETA 30
Acrylmorpholine ACMO 10
NPGDA 12
Polymerization inhibitor (510) 0.1
1173 4
369 2.5
Polyethylene wax 1.5
Hydrophobic pyrogenic silica 1
Pigment (Lysol Red) 12
Silicone-free leveling agent 0.4
Silicone-free defoamer 0.5
(3) UV Yellow Gravure Ink Reference Formulation
Hexafunctional PUA 4
Difunctionality PEA 5
DTMPTA 25
PETA 26
Acrylmorpholine ACMO 10
NPGDA 12
Polymerization inhibitor (510) 0.1
1173 4
369 2
Polyethylene wax 1
Hydrophobic fumed silica 1
Pigment (benzidine yellow GR) 9
Silicone-free leveling agent 0.4
Silicone-free defoamer 0.5
(4) UV blue gravure ink reference formula
Hexafunctionality PUA 5
Difunctionality PEA 3
DTMPTA 30
PETA 18
Acryloylmorpholine ACMO 14
NPGDA 8
Polymerization inhibitor (510) 0.1
1173 5
369 3
Polyethylene wax 1
Hydrophobic fumed silica 1
Pigment (phthalocyanine blue BX) 11
Silicone-free leveling agent 0.4
Silicone-free defoamer 0.5
(5) UV Gravure Brightening Oil Reference Formulation
Polyurethane bis acrylate 38.11
Hexylene glycol diacrylate 27.64
Gasil EBC (trade name) 8.59
Benzophenone 2.83
N-methyldiethanolamine 2.83
The above UV gravure varnish formulations are often used for varnishing wood grain paper for furniture, etc.
A practical selection route for photoinitiator-related projects
When technical buyers or formulators screen photoinitiators, the most useful decision frame is usually cure quality plus application fit: which package cures reliably, keeps appearance acceptable, and still works under the lamp, film thickness, and substrate conditions of the actual process.
- Match the package to the lamp first: mercury lamps, UV LEDs, and visible-light systems can rank the same photoinitiators very differently.
- Check depth cure and surface cure separately: a film that feels dry on top can still be weak underneath.
- Balance yellowing with reactivity: the strongest deep-cure route is not always the best commercial choice if color or migration risk becomes unacceptable.
- Use the final formula as the benchmark: pigment load, monomer package, and film thickness can all change the apparent ranking of the same initiator.
Recommended product references
- CHLUMINIT 819: Useful when a formulation needs stronger absorption and deeper cure support.
- CHLUMINIT 1173: A practical comparison point for classic short-wave UV initiation.
- CHLUMINIT BP: A practical type-II benchmark when benzophenone chemistry is under review.
- CHLUMICRYL TMPTA: A standard reactive monomer benchmark when stronger crosslink density is required.
FAQ for buyers and formulators
Why are blended photoinitiator packages so common?
Because one product may control yellowing or lamp fit well while another improves cure depth or line-speed performance, so the full package is often stronger than any single grade.
Should incomplete cure always be solved by adding more initiator?
Not automatically. The real limitation may be the lamp, film thickness, pigment shading, or the rest of the reactive system rather than simple under-dosage.