Laser-induced crosslinking polymerization of acrylic photoresists

Abstract

Multifunctional acrylate photoresists have been polymerized within milliseconds by laser irradiation to produce an insoluble polymer network. The polymerization reaction and the insolubilization process were both followed quantitatively by infrared spectroscopy. The most sensitive system consisted of a morpholino-ketone photoinitiator, a triacrylate monomer, and an amino-polyester tetra-acrylate oligomer. An energy as low as 0.1 mJ cm 02 proved to be sufficient to achieve insolubilization of a 36 mm thick film upon exposure to a Kr / laser beam (337 nm) in an inert atmosphere. These highly photosensitive materials are well suited for the manufacturing of printed circuit boards by a laser direct imaging technology. Dry acrylate photoresists were found to be less sensitive than wet photoresists because of severe mobility restrictions in the solid state. A similar drop in photosensitivity was observed when wet acrylate photoresists were exposed to the 488 nm emission of an argon ion laser because of the lower efficiency in radical production of visible photoinitiators.

Photoinitiated polymerization of a dental formulation: 1. Influence of photoinitiating system, temperature and luminous intensity

“…The development of a photosensitive dental composite resin [7], results from a knowledge which takes into account not only the quantum yield of the photoinitiator (linked to the wavelength of the light) [8], the chemical nature and the functionality of the monomer [9,10], the fillers and the additives [11], but also to understand well that during the photopolymerization of composite resins, the transformation of the initially viscous material, into a polymer network strongly crosslinked is usually accompanied by one increase of the viscosity and characteristic phenomena appear [12,13]: autoacceleration at the beginning of po!ymerization [14,15], limited conversion of polymerizable functions [16], propagation and termination reactions controlled by diffusion [17], and volume shrinkage [18]. This complex process and the high rate of this reaction As well as the exothermic effect resulting from the reaction may be the cause of defects in the final material.…”

Laser-induced curing of functional polymers

“…In this respect, it should be mentioned that when this formulation was exposed to sunlight between two glass plates, the hardening occurred within less than 1 s, thus bonding tightly together the two pieces of glass. The high sensitivity of these photoresists makes them particularly well suited for laser direct imaging applications, with writing speeds which can reach 1000 m s-1 [20].…”

“…This limitation can be partly overcome by increasing the initiation rate through laser irradiation. Three-dimensional polymer networks have thus been synthesized within seconds by laser-induced polymerization of telechelic oligomers or of polymers bearing pendant reactive groups [ 11 ].…”

Synthesis and Photopolymerization of 2,2-Di((Acryloyloxy)Methyl)Butyl Bis(2-(Acryloyloxy)Ethyl)Carbamate

“…Photopolymerization processes have found a large variety of industrial applications, mainly in dental materials, paints, printing, adhesive, coatings, biomaterials and photolithography [1][2][3]. Photoinduced polymerization is a rapidly expanding technology resulting from its main advantages: solvent-free, energy efficient and generally economical [4].…”