Photobase generators derived from trans-o -coumaric acid for anionic UV curing systems without gas generation

Abstract

Anionic UV curing systems of poly(glycerol methacrylate) and/or poly[3‐(methacryloyloxy)propyltrimethoxysilane] are obtained using novel photobase generators (PBGs) derived from trans‐o‐coumaric acid. These PBGs decompose into amines and coumarins by UV irradiation without generation of gases that cause cracks and bubbles in cured films.

A dismantlable photoadhesion system fabricated by an anionic UV curing of epoxy resins with a base amplifier having a disulfide bond

“…1 H‐ and C‐NMR measurements were performed using a JEOL JNM‐AL300. FT‐IR measurements were performed using a JASCO FT/IR‐6100 spectrometer.…”

“…1 H‐NMR (300 MHz, CDCl 3 , δ ): 7.6–7.8 (m, 4H; fluorenyl‐H), 7.5–7.6 (m, 2H; CH 2 NH), 7.4–7.6 (m, 4H; fluorenyl‐H), 7.3–7.4 (m, 8H; fluorenyl‐H), 4.3–4.4 (m, 4H; CHCH 2 ), 4.1–4.2 (m, 2H; CHCH 2 ), 3.2–3.4 (m, 2H; CH 2 NH), 2.77 (t, J = 6.0 Hz, 4H; CH 2 S); C‐NMR (75 MHz, CDCl 3 , δ ): 156.1, 145.2, 140.7, 127.6, 127.0, 125.2, 120.1, 65.4, 50.1, 46.7, 37.4; FT‐IR (neat): ν = 3310, 3040, 2940, 1697, 1530, 1448, 1226 cm −1 ; HRMS (FAB, m/z ): [ M + Na] + calcd for C 34 H 32 O 4 N 2 S 2 Na, 619.16969; found, 619.17012; T d : 175 °C.…”

“…Anionic UV curing has been featured in industrial fields because it could circumvent oxygen inhibition of polymerizations, volume contraction of the resulting cured materials, and corrosion of metallic substrates, compared with radical or cationic UV curing . The anionic system consists of a photobase generator (PBG) and a base‐reactive resin or polymer, and many kinds of PBGs have been developed . Photogenerated bases from PBGs are amines and amidines, for example, imidazoles.…”

365nm-Light-sensitive photobase generators derived from trans-o-coumaric acid

“…The protection reaction proceeds with an amine and trans-o-coumaric acid, and the deprotection occurs through a trans-cis isomerization triggered by UV irradiation. We have applied this chemical structure to the design of PBGs that were mainly used with 254 nm-light irradiation because of their absorption wavelength region [10]. However, light sources such as powerful LED lamps of 365 nm-light (i line) have recently been introduced in industry and the laboratory, and it is necessary to develop PBGs for these needs.…”

Photosensitivity Characteristics of Novel Resists Consisting of a Photobase Generator and an Epoxy Resin

“…Although photosensitive materials based on base-catalyzed reactions have merit in preventing erosion of metallic substrates, PBGs generally have lower quantum yields when compared to PAGs. Recently, in order to improve photosensitivity, some papers regarding PBGs with high quantum yields have been reported, but it has not been yet applied to photopatterning materials [4][5][6][7][8][9]. There is a few report concerning photopatterning materials based on epoxy resins utilizing PBGs.…”