Photocurable ink

Ongoing investigation in preparing oxime photochemical initiators. Photocurable inks Photosensitive plates... 

Planar lithography techniques are not effective for precise fabrication of microdevices with hemispherical shapes (17). Drop-on-demand inkjet printing of a photocurable ink is a more appropriate approach as it takes advantage of the surface tension as well as of the delivery of a well-defined ink volume. 

A photocurable ink composition that contains a dendrimer has been described. The dendritic polymer has a molecule structure in which a functional group is dense on the surface with high density in comparison to a linear polymer. 

H. Nakane, Photocurable ink composition for ink jet recording, ink jet recording method, and recorded material, US Patent 8 556 404, assigned to Seiko Epson Corporation (Tokyo, JP), October 15, 2013. 

An acrylate-based photocurable ink is used. The surface of the substrate to be printed must be pretreated in several steps, including oxygen plasma treatment, surface hydroxylation, and an anti-adhesion treatment. Onto this surface, the ink can be printed by the drop-on-demand method. The angle of the lenses depends on the method of pretreatment (20). 

This photocurable ink design can be extended to many polymeric systems, including poly(2-hydroxyethyl methacrylate), a well-characterized, biocompatible hydrogel material [30]. We therefore envision many opportunities to further tailor the scaffold chemistry, mechanical properties, and structure to improve cell viability on these novel constructs. 

Takemasa, K. Kakino, R. Fabrication of presensitized lithographic plates and clogging-resistant photocurable inks therefor. Jpn. Kokai Tokkyo Koho JP 2008075056, 2008 Chem. Abstr. 2008, 148, 390923. 

For aqueous inks, the resins are water- or alkali-soluble or dispersible and the solvent is mosdy water containing sufficient alcohol (as much as 25%) to help solubilize the resin. To keep the alkah-soluble resin in solution, pH must be maintained at the correct level. Advances include the development of uv inks. These are high viscosity inks that require no drying but are photocurable by uv radiation. In these formulations, the solvent is replaced by monomers and photoinitiators that can be cross-linked by exposure to uv radiation. The advantage of this system is the complete elimination of volatile organic compounds (VOC) as components of the system and better halftone print quaUty. Aqueous and uv inks are becoming more popular as environmental pressure to reduce VOC increases. 

An advantage of this type of photopolymerizations is that as they are non-radical chain polymerizations, they are insensitive to oxygen. In addition, as the cation is relatively stable, the reaction is able to continue in the dark. Applications of this chemistry may be found in the fields of coatings, adhesives, printing inks, and also for photocurable composites and microelectronic photoresists. 

Recent concerns over the residual concentration of free thioxanthone photoinitiators and amine coinitiators in coatings and inks on food packaging have resulted in the evolution of macroinitiators <2002PLM4591, 2003JPH(159)103> or polymeric photoinitiators <1996MI379> wherein the thioxanthone unit and, in some instances, the amine coinitiator are covalently bound to a copolymer which is formulated with the ink or coating and then photocured in the normal way. Several copolymers, for example, 636, based upon the polymerization of acrylate esters derived from 4-hydroxythioxanthones with either acrylamide or 2-acryloxyethyltrimethylammonium iodide co-monomer have been explored as water-soluble photoinitiators <2005JPH(169)95>. 

Chem. Descrip. Benzil dimethyl ketal CAS 24650-42-8 EINECS/ELINCS 246-386-6 Uses UV photolnitiator in coatings, inks, and adhesives Photocure 81 [Aceto]... 

Uses Fixative in perfumes photoinitiator for UV-curable systems, coatings, inks, adhesives in org. synthesis Mamif./Dislrib. Aceto Aldrich Trade Names Photocure 196... 

Photopolymers These are photoinitiated and photo-cross-linked polymers e.g., photoresists, printing inks, can coatings, etc. Fouassier J-P (1995) Photoinitiation, photopolymerization and photocuring. Hanser-Gardner Publications, New York. Leach RH, Pierce RJ, Hickman EP, Mackenzie MJ, Smith HG (eds) (1993) Printing ink manual, 5th edn. Blueprint, New York. 

An ink for inkjet printing on ceramic surfaces such as glass has been described. The composition contains glass frits or silica nanoparticles. As organic polymeric binder a poly(acrylate) or poly(N-vinyl-2-pyrrolidone) is used. In addition, photocurable monomers are in the composition. These are listed in Table 5.13. 

Materials for Photocurable Coatings and Inks, Union Carbide Corp., New York. 

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