Particulate photoinitiators and uses thereof

Abstract

Provided is a novel class of solid water-dispersible powders, including a plurality of water-insoluble photoinitiators in nanoparticle forms for use in water-based ink formulations.

1 .- 56 . (canceled) 
     
     
         57 . An aqueous UV curable ink formulation comprising a dispersed powder comprising a plurality of nanoparticles, said nanoparticles consisting of at least one water-insoluble photoinitiator material, at least one surfactant and optionally at least one crystallization inhibitor, the ink being essentially free of organic solvents. 
     
     
         58 . The formulation according to  claim 57 , being free of photoinitiators in a non-particulate or micelle form. 
     
     
         59 . The formulation according to  claim 57 , comprising at least one crystallization inhibitor. 
     
     
         60 . The formulation according to  claim 57 , wherein the water-insoluble photoinitiator material has a molar extinction coefficient of 10 and 1,000 M-1 cm-1 at between 300 and 800 nm. 
     
     
         61 . The formulation according to  claim 57 , wherein the water-insoluble photoinitiator is selected from 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO), Titanocene 1784, Camphorquinone (CQ), 2-isopropylthioxanthone (ITX), N,N-dimethylaminobenzoic acid ethyl ester (DMAB), monoacylphosphine oxide, bisacylphosphine oxides, 2-Benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 1,5-diphenyl-1,4-diyn-3-one (Diinone), 1-hydroxycyclohexylphenyl ketone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one, 2,2-dimethoxy-1,2-diphenylethan-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone and diethoxyacetophenone. 
     
     
         62 . The formulation according to  claim 57 , wherein the water-insoluble photoinitiator is a two-photon polymerization photoinitiator. 
     
     
         63 . The formulation according to  claim 57 , wherein the at least one surfactant is selected from a cationic surfactant, an anionic surfactant, an amphoteric surfactant, a non-ionic surfactant and mixtures thereof. 
     
     
         64 . The formulation according to  claim 57 , wherein the at least one surfactant is selected from polysorbates, alkyl polyglycol ethers, alkyl phenol polyglycol ethers and sulfosuccinate salts. 
     
     
         65 . The formulation according to  claim 57 , wherein the at least one surfactant is selected from ethoxylated sorbitan monooleate (Tween 80), sodium dodecyl sulfate, polyglycerol esters and ethoxilated alcohols (Brij), sorbitan molooleate (Span 80) and combinations thereof. 
     
     
         66 . The formulation according to  claim 57 , in a form of a micellar solution. 
     
     
         67 . A method of printing a 2D or 3D pattern or object, the method comprising irradiating a pattern of a curable ink comprising a dispersible powder comprising a plurality of nanoparticles, said nanoparticles consisting of at least one water-insoluble photoinitiator material, at least one surfactant and at least one crystallization inhibitor, said irradiation being with light of a wavelength selected to cause polymerization of the at least one polymerizable material. 
     
     
         68 . The method according to  claim 67 , wherein the curable ink is a UV curable ink. 
     
     
         69 . The method according to  claim 67 , wherein polymerization occurs at a wavelength between 300 and 800 nm. 
     
     
         70 . The method according to  claim 67 , wherein the 3D pattern is a 3D hydrogel. 
     
     
         71 . The method according to  claim 67 , for constructing at least one device or element for use in medical and biotechnological applications. 
     
     
         72 . The formulation according to  claim 57 , wherein the at least one surfactant comprises a cationic surfactant. 
     
     
         73 . The formulation according to  claim 57 , wherein the at least one surfactant comprises an anionic surfactant. 
     
     
         74 . The formulation according to  claim 57 , wherein the at least one surfactant comprises a non-ionic surfactant.