Photoinitiator‐free photopolymerization of acrylate‐bismaleimide mixtures and their application for inkjet printing

Abstract

There is growing interest in using photoinitiator-free systems in coating applications such as inkjet-printing, because residual photoinitiator can alter the properties of the resulting polymer. Bismaleimides (BMI) offer the opportunity to polymerize acrylates without the addition of photoinitiators, as this class of molecules can serve both as polymerizable monomer and as photoinitiator together with electron donor systems, like vinyl ether monomers or acrylates. The UV-induced copolymerization of a low-molecular-weight BMI with various acrylate monomers and oligomers without any photoinitiator was characterized. The BMI-acrylate systems show comparable polymerization speeds to widely used acrylic systems with photoinitiator. Superior thermal stability as well as thermomechanical properties are achieved by enhancing acrylics with BMI. Such photoinitiator-free systems lend themselves to be used for low-migration coatings as well as for high-temperature applications. Here, a characterization of selected BMI-acrylate mixtures regarding their photocuring kinetics and their application as inks for inkjet printing is shown.BMIs contain two reactive double bonds and can serve both as polymerizable monomer and as photoinitiator for other monomers, such as acrylates or vinyl ethers. As a result of UV-irradiation, BMIs Additional Supporting Information may be found in the online version of this article.

Novel Multifunctional Epoxy (Meth)Acrylate Resins and Coatings Preparation via Cationic and Free-Radical Photopolymerization

“…Due to its advantages, photopolymerization is seen as a pro-ecological technique, especially if cheap light-emitting diodes (LEDs) are used as a source of radiation. Light-induced polymerization is perceived as a modern method of curing because it is most often used to cure thin-film materials such as coatings, adhesives, printing inks [ 5 , 6 , 7 , 8 ], and others, such as dental fillings, hydrogels, or 3D-printed items [ 9 , 10 , 11 ]. Most commonly, depending on the type of photocurable material (resin, monomer, photoinitiator) and thus the emerging active centers that initiate the polyreactions, the reaction proceeds according to a radical or cationic mechanism.…”

A review on self-initiated and photoinitiator-free system for photopolymerization

“…In the inject printing sector, the photopolymer [11] is used for designing waveguide by inkjet printing [50], for the development of digital colour printing [51] and advancement of 3D nanocomposites [52].…”

“…The electron donor/acceptor system appears to be an effective alternative since it shows rapid curing on radiation, while some systems are less sensitive to oxygen [51,[113][114][115][116]. Its efficiency depends on the combination of electron donor/ acceptor monomers used in the formulation.…”

“…The structures of monomers are depicted in Table 4. In such a system, acceptors like MI and their derivatives, when radiated with UV light transit from the ground state to an excited state, wherein they abstract hydrogen from a donor monomer such as vinyl ether, or within the monomer, or copolymer, or external additives [51,118,121]. Figure 12 depicts the abstraction of hydrogen from donor monomer.…”

Influence of radical photoinitiators on features of polyacrylate syrups and self-adhesives

“…However, the most common photo polymerization method is film photopolymerization (radical or cationic), for example photopolymerization of acrylates, epoxides, vinyl ethers. This type of photopoly merization is mainly used for cross-linking of polymeric materials, such as: varnishes, hydrogels, dental fillings, printing inks and adhesives [8][9][10][11][12][13]. Photopolymerization in film is extremely effective, especially radical photopoly merization of multifunctional monomers and oligomers is very fast -in seconds, with the help of light, a viscous liquid turns into a solid.…”