Sulfonium salt photoinitiators and methods for LED curing of compositions containing the sulfonium salt photoinitiators

Abstract

The present invention relates to a method for producing a cationically polymerizable compound having the formula (I): and a photoinitiator according to TIFF2026500735000129.tif73170, the method comprising irradiating the composition with at least one light source having a maximum output wavelength in the range of 350 to 460 nm; the resulting cured product; a method for preparing a 3D printed article comprising the method; and the resulting 3D printed article.

Description

[Technical Field]

[0001] The present invention relates to a method for curing a composition comprising a cationically polymerizable compound and a photoinitiator, the method comprising irradiating the composition with at least one light source having a maximum output wavelength in the range of 350-460 nm, the resulting cured product, a method for preparing a 3D printed article comprising said method, and the resulting 3D printed article.

[0002] Stereolithography (SLA or SL) is a form of 3D printing technology used to create 3D articles or parts thereof layer-by-layer using a photochemical process in which polymerizable compounds are cross-linked together by light to form polymers.

[0003] (Meth)acrylate stereolithography resins suffer from high volumetric shrinkage and high shrinkage stress.

[0004] Hybrid systems containing both radically curable (meth)acrylates and cationic curable epoxides overcome the limitations of (meth)acrylate-based resins and have become one of the most successful innovations in the history of SL resins. The hybrid system simultaneously builds an interpenetrating polymer network (IPN), eliminates the oxygen inhibition of (meth)acrylates, and reduces viscosity, resulting in faster process speeds, easier part cleaning, significantly increased part support due to improved green strength, and elimination of warpage and distortion during printing.

[0005] Cationic curing in hybrid systems mostly involves the ring-opening polymerization of the epoxides used, which not only reduces volumetric shrinkage but also shrinkage stresses due to slower curing rates than (meth)acrylate curing during green part fabrication. One important advantage of cationic curing is the ability to post-cure the green parts; the so-called dark cure of the cationic polymerization continues during aging, with full development of mechanical properties after a few days.

[0006] 3D printers equipped with longer wavelength LED lamps are rapidly gaining popularity due to the long penetration depth, low health hazards, and cost-effectiveness of LED light.

[0007] In a typical hybrid photocurable 3D resin (requiring both radical and cationic curing), both radical and cationic initiators are required. These photoinitiators absorb photons upon irradiation and form radical or cationic species from their excited state, which initiate the stepwise photopolymerization of the UV-curable 3D resin.

[0008] Among photoinitiators for LED-curable 3D resins, many commercially available type I and type II radical initiators show good agreement between their absorption lines and the LED emission spectrum of 3D printers, resulting in efficient photoreactivity and high curing speeds for radical-curable monomers and / or oligomers. For example, acylphosphine oxides are considered efficient radical photoinitiators because they have a red-shifted absorption band in the 350-420 nm range, which is compatible with the emission range of many LEDs.

[0009] However, long-wavelength photoinitiating systems for cationic photopolymerization have been a bottleneck in the development of LED-curable cationic systems and hybrid systems for 3D LED printers. Currently available commercially available iodonium and sulfonium salts exhibit short-wavelength light absorption around 220–320 nm, which has very limited overlap with the LED emission spectrum of 3D printers.

[0010] In recent years, there has been growing interest in expanding the wavelength range of cationic photoinitiation systems. Three typical approaches have been developed: 1) Designing new onium salts with long-wavelength absorbing chromophores, such as the sulfonium salt Omnicat 550; 2) Photosensitizing common onium salts with various visible light sensitizers such as SpeedCure® CPTX; 3) Cationic cure is promoted using a radical initiator such as SpeedCure® BKL.

[0011] To date, all three approaches have been successfully applied to extend the optical absorption of iodonium salts to longer wavelengths, making them very attractive systems in the academic field. Unfortunately, iodonium salts have rather poor thermal stability. The short shelf life of LED-curable products developed from them limits their industrial applications, including 3D printing.

[0012] Sulfonium salts have become the preferred cationic photoinitiators for many industrial applications because they typically have better thermal stability and longer wavelength absorption, matching the LED emission spectrum better than iodonium salts. However, commercially available sulfonium salts still have a significant gap in compatibility with LED lamp wavelengths above 350 nm. First, it is well documented that sulfonium salts are difficult or unfavorable to sensitize with photosensitizers. This is because the free energy barrier for electron transfer between sulfonium salts and most photosensitizers is significantly higher than that between iodonium salts and photosensitizers. Only a few photosensitizers, such as 9,10-dibutoxyanthracene (UVS-1101 from Nagase), work well in the particularly effective dose range of 0.4–0.6%. Second, commercially available sulfonium salts are also notoriously difficult to sensitize with radical photoinitiators. The half-wave reduction potential E of sulfonium salts is 1 / 2 red Because the (On+) (-1.2 V vs. SCE) is significantly lower than that of iodonium salts (-0.2 V vs. SCE), sulfonium salts cannot oxidize the free radicals generated from radical photoinitiators, nor can they facilitate the electron transfer process that generates cationic initiating species. Of the three strategies to promote the longer wavelength of sulfonium salts, two have so far been less successful. The most successful option to date is to modify the structure of the sulfonium salt by introducing a chromophore. BASF's lrgacure PAG290 - B(C6F5)4 salt] or PAG270( -PF6 salts), IGM's Omnicat 550 or Omnicat 650 are sulfonium salts of this type that have been commercially successful over the past few years, but these sulfonium salts are not sufficiently red-shifted to successfully cure cationic or hybrid resins with LED lamps above 350 nm.

[0013] Therefore, there is a need for photoinitiating systems for cationic photopolymerization that can be used at longer wavelengths, particularly within the LED emission spectrum.

[0014] According to a first object, the present invention provides a method for producing a cationically polymerizable compound having the formula (I): TIFF2026500735000002.tif73170 (in the above formula, Y is an anion with a valence of y, -R 12 and R 13 are bonded to each other to form groups TIFF2026500735000003.tif38170 TIFF2026500735000004.tif51170, where: -R 16 , R 17 , R 18 and R 19 are independently H, halogen, a (C1-C6) straight or branched chain alkyl group, a (C1-C6) straight or branched chain alkoxy group, -O-(CH2) i -COOR 28 or -(CH2) i -CH-(COOR 28 ) groups (where i is 1 or 2 and R 28 is selected from H or a (C1-C4) straight or branched chain alkyl group; -R 11 , R 14 and R 15 are independently H, halogen, a (C1-C6) straight or branched chain alkyl group, a (C1-C6) straight or branched chain alkoxy group, and -S-Ph-C(=O)-Ph; - Or R 12 and R 13are not bonded to each other, and R 11 , R 12 and R 13 are independently H, halogen, a (C1-C6) straight or branched chain alkyl group, a (C1-C6) straight or branched chain alkoxy group, pyrrolidin-1-yl, -L-Ph 1 group (where L is a single bond, CH2 or O, and Ph 1 is a phenyl group optionally substituted with one or several substituents selected from halogen, (C1-C6) linear or branched alkyl groups and (C1-C6) linear or branched alkoxy groups, with the proviso that R 11 , R 12 and R 13 At least one of the is -L-Ph 1 is a group, and R 14 and R 15 are independently H, halogen, a (C1-C6) straight or branched chain alkyl group, a (C1-C6) straight or branched chain alkoxy group, and -S-Ph-C(=O)-Ph; -R 3 is H, halogen, (C1-C6) linear or branched alkyl group, (C1-C6) linear or branched alkoxy group, -O-(CH2) l -COOR 31 group and -(CH2) l -CH-(COOR 31 ) groups (where l is 1 or 2 and R 31 is selected from H or a (C1-C4) straight or branched chain alkyl group; -R 2 , R 4 , R 5 , R 7 , R 8 , R 9 and R 10 are independently selected from H, halogen, (C1-C6) straight or branched alkyl group, (C1-C6) straight or branched alkoxy group, and -O-(CH2) m -COOR 32 or -(CH2) m -CH-(COOR 32 ) groups (where m is 1 or 2, and R32 is selected from H or a (C1-C4) straight or branched chain alkyl group and a photoinitiator comprising irradiating the composition with at least one light source having a maximum output wavelength in the range of 350 to 460 nm.

[0015] Photoinitiators are generally classified into two classes based on their mechanism of action: radical photoinitiators and cationic photoinitiators. Upon irradiation, cationic photoinitiators undergo homolytic or heterolytic bond cleavage to form fragments that either decompose or further react to generate Bronsted or Lewis acids. The resulting acids then initiate polymerization. Radical photoinitiators can employ two distinct mechanisms of action, which are classified as Norrish Type I and Norrish Type II photoinitiators. As used herein, the term "active" with respect to Norrish Type I activity and Norrish Type II activity is intended to refer to Norrish photoinitiation and similar reactions. For example, photoinitiators with Norrish Type I activity are characterized by a reaction in which the original photoinitiator splits into two radical fragments upon exposure to light. Initiators with Norrish Type II activity, exposure to light results in the abstraction of atoms, such as hydrogen, to generate radicals.

[0016] The sulfonium salts of formula (I) are type I radical photoinitiators, advantageously red-shifted to wavelengths of 420 nm, making them compatible with the majority of commercially available LED lamps and enabling the curing of cationic or hybrid systems with 3D printer-mounted LED lamps.

[0017] Compared to conventional photoinitiators, sulfonium salts of formula (I) enable cure rates comparable to or faster than those achieved with iodonium salts in combination with thioxanthone sensitizers, and faster than those achieved with commercially available sulfonium salts, resulting in excellent green strength of printed parts. Photoinitiators of formula (I) offer the advantage of high cure speeds, particularly in purely cationic (e.g., epoxy and / or oxetane-based) and hybrid (e.g., epoxy / (meth)acrylate-based) formulations when cured with a 350-460 nm light source. In hybrid formulations, sulfonium salts of formula (I) achieve high conversion of both types of monomers without phase separation, resulting in high strength and low shrinkage.

[0018] Photoinitiators of formula (I) exhibit acceptable yellowing and / or light fade properties, which are important in printing ink and additive manufacturing applications. This low yellowing property can be measured by the color index "b" value of the cured film.

[0019] Formulations comprising monomers and photoinitiators of formula (I) advantageously provide excellent thermal stability to LED-curable cationic or hybrid products for 3D printing.

[0020] The curable composition may comprise from 0.05% to 10%, particularly from 0.1% to 5%, more particularly from 0.5 to 2% by weight of a photoinitiator of formula (I), based on the total weight of the curable composition.

[0021] The method according to the present invention comprises irradiating the composition with at least one light source having a maximum output wavelength in the range of 350 to 460 nm, preferably 365 to 450 nm, in particular 380 to 430 nm, even more preferably 385 nm or 395 nm or 405 nm or 420 nm.

[0022] The light source is typically a broadband lamp or light emitting diode (LED) equipped with an optical filter that limits the emission to wavelengths in the range of 350 to 460 nm.

[0023] The following preferred embodiments may be considered alone or, where applicable, in combination with one another, and, where applicable, may apply to formula (I) and to any one of the formulae described below, in particular to any one of formulae (II) to (XV): - (C1-C6) linear or branched alkyl group is a (C1-C3) linear or branched alkyl group, preferably methyl (Me), ethyl (Et), isopropyl (iPr) or n-propyl (nPr), - (C1-C6) linear or branched alkoxy group is a (C1-C3) linear or branched alkoxy group, preferably -OMe, OEt, OiPr, -OnPr, halogen is Cl or F, -R 12 and R 13 are bonded to each other to form groups TIFF2026500735000005.tif38170 TIFF2026500735000006.tif42170, -R 7 , R 8 , R 9 and R 10 represents H, -R 8 and / or R 13 is not a methyl group, and / or -R 3 and R 8 is not Me, but preferably R 2 , R 3 , R 4 , R 5 , R 7 , R 8 , R 9 and R 10 None of these are iPrs, -R 2 and R 7 is not a halogen, -R 3 , R 5 , R 8 and R 10 None of these are Et, -R 11 , R 14 and R 15are independently H, halogen, a (C1-C6) straight or branched chain alkyl group, or a (C1-C6) straight or branched chain alkoxy group; -R 12 and R 13 At least one group is -L-Ph 1 group, preferably R 12 and R 13 One of the groups is -L-Ph 1 It is the basis, L is a single bond; - Ph 1 is a phenyl group optionally substituted with one substituent selected from halogen, a (C1-C6) linear or branched alkyl group, and a (C1-C6) linear or branched alkoxy group, preferably a (C1-C6) linear or branched alkoxy group, most preferably a methoxy group; and / or - When L is a single bond, Ph 1 is a phenyl group substituted with at least one (C1-C6) straight or branched alkoxy group.

[0024] In any of the formulas described in this application, the anion Y y- is preferably a halide (F - , Cl - , Br - , I - ), HSO4-, SO4 2- , ClO4 - , BF4 - , PF6 - , AsF6 - , SbF6 - , SbF5(OH) - , SbF4(OH)2 - , BPh4 - , B(C6F5)4 - , Al[OC(CF3)3]4 - , CH3COO - , CH3SO3 - , CH3C6H4SO3 - , CF3COO - , CF3SO3 - , N(CF3SO3)2 - , or B[C6H3(CF3)2]4- and most preferably PF6 - , SbF6 - and B(C6F5)4 - is selected from.

[0025] In a first alternative embodiment, in formula (I), R 12 and R 13 are bonded to each other, and the groups TIFF2026500735000007.tif38170 TIFF2026500735000008.tif51170, wherein the photoinitiator is a compound represented by formula (IV): TIFF2026500735000009.tif77170 (in the above formula, R 2 , R 3 , R 4 , R 5 , R 7 , R 8 , R 9 , R 10 , R 11 , R 14 , R 15 , R 16 , R 17 , R 18 , R 19 , Y and y are as described above) Matches.

[0026] Thus, in formula (IV): -R 16 , R 17 , R 18 and R 19 are independently H, halogen, a (C1-C6) straight or branched alkyl group, a (C1-C6) straight or branched alkoxy group, -O-(CH2) i -COOR 28 or -(CH2) i -CH-(COOR 28 ) groups (where i is 1 or 2 and R 28 is selected from H or a (C1-C4) straight or branched alkyl group; -R 11 , R 14 , R 15are independently H, halogen, a (C1-C6) straight or branched chain alkyl group, a (C1-C6) straight or branched chain alkoxy group, and -S-Ph-C(=O)-Ph.

[0027] The preferred embodiments described below can be considered alone or, where applicable, in combination with one another and are also applicable to formula (IV) and, where applicable, to formula (V) or (V') described below: -R 8 represents H, -R 7 , R 8 , R 9 and R 10 represents H, -R 11 , R 14 and R 15 represents H, -R 4 is H, -R 2 , R 4 , R 7 , R 8 , R 9 and R 10 represents H, and R 5 is selected from H, halogen, (C1-C6) straight or branched alkyl group, and R 3 is a halogen, a (C1-C6) straight or branched alkyl group, a (C1-C6) straight or branched alkoxy group, -O-(CH2) l -COOR 31 group and -(CH2) l -CH-(COOR 31 ) groups (where l is 1 or 2 and R 31 is selected from H or a (C1-C4) straight or branched chain alkyl group, and R 3 is preferably selected from halogen, (C1-C6) linear or branched alkyl groups and (C1-C6) linear or branched alkoxy groups, R 3 is most preferably a (C1-C6) straight or branched chain alkyl group, or R 3 , R 4 , R 7 , R 8 , R 9 and R10 is H and R 2 and R 5 are independently selected from halogen, (C1-C6) straight or branched alkyl group, (C1-C6) straight or branched alkoxy group, and -O-(CH2) m -COOR 32 or -(CH2) m -CH-(COOR 32 ) groups (where m is 1 or 2, and R 32 is selected from H or a (C1-C4) straight or branched chain alkyl group, and R 2 and R 5 are independently preferably selected from halogen, (C1-C6) straight or branched alkyl groups and (C1-C6) straight or branched alkoxy groups; R 2 and R 5 are most preferably independently selected from halogen and (C1-C6) straight or branched alkoxy groups; and / or -R 16 , R 18 , R 11 , R 14 and R 15 represents H, and R 19 is selected from H, halogen, (C1-C6) straight or branched alkyl group, and R 17 is a halogen, a (C1-C6) straight or branched alkyl group, a (C1-C6) straight or branched alkoxy group, -O-(CH2) i -COOR 28 or -(CH2) i -CH-(COOR 28 ) groups (where i is 1 or 2 and R 28 is selected from H or a (C1-C4) straight or branched chain alkyl group, and R 17 is preferably selected from halogen, (C1-C6) linear or branched alkyl groups and (C1-C6) linear or branched alkoxy groups, R 17 is most preferably a (C1-C6) straight or branched chain alkyl group, or R 17 , R 18 , R 11 , R 14 and R 15is H and R 16 and R 19 are independently selected from halogen, (C1-C6) straight or branched alkyl groups, (C1-C6) straight or branched alkoxy groups, and -O-(CH2) i -COOR 28 or -(CH2) i -CH-(COOR 28 ) groups (where i is 1 or 2 and R 28 is selected from H or a (C1-C4) straight or branched chain alkyl group, and R 16 and R 19 are independently preferably selected from halogen, (C1-C6) straight or branched alkyl groups, and (C1-C6) straight or branched alkoxy groups; R 16 and R 19 are independently most preferably selected from halogen and (C1-C6) straight or branched alkoxy groups.

[0028] Preferred photoinitiators of formula (IV) are represented by formula (1), (5), (6), (40), (44), (45), (46), (47), (48) or (49), most preferably by formula (1) or (5): TIFF2026500735000010.tif63170TIFF2026500735000011.tif59170TIFF202650073500001 2.tif68170TIFF2026500735000013.tif87170TIFF2026500735000014.tif82170TIFF202650 0735000015.tif90170TIFF2026500735000016.tif87170TIFF2026500735000017.tif81170TIFF2026500735000018.tif58170TIFF2026500735000019.tif59170 (wherein Y and y are as defined above) It has the following characteristics.

[0029] Preferably, in formula (IV), R 7 and R 11 are identical, R9 and R 15 are identical, R 10 and R 14 are identical, R 2 and R 16 are identical, R 3 and R 17 are identical, R 4 and R 18 are identical, and R 5 and R 19 are identical and the photoinitiator has formula (V): TIFF2026500735000020.tif76170 (in the above formula, -R 7 , R 9 and R 10 are independently H, halogen, a (C1-C6) straight or branched chain alkyl group, or a (C1-C6) straight or branched chain alkoxy group; -R 2 , R 3 , R 4 and R 5 are independently H, halogen, a (C1-C6) straight or branched alkyl group, a (C1-C6) straight or branched alkoxy group, -O-(CH2) m -COOR 32 or -(CH2) m -CH-(COOR 32 ) groups (where m is 1 or 2 and R 32 is selected from H or a (C1-C4) straight or branched chain alkyl group, and -R 8 , Y and y are as described above) It has.

[0030] Preferred photoinitiators of formula (V) are those having formula (1), (5), (6), (40), (44) or (45) set forth above, most preferably formula (1) or (5).

[0031] Preferably, R 8 is H and the photoinitiator has the formula (V'): TIFF2026500735000021.tif68170 (in the above formula, R 2 , R 3 , R 4 , R 5 , R 7 , R 9 , R 10 , Y and y are as described above. Advantageously, as will be described below, these compounds can be prepared under mild conditions. Y is an anion whose valence is y, -R 3 , R 4 , R 7 , R 9 and R 10 is H, and -R 2 and R 5 are independently selected from halogen, (C1-C6) straight or branched alkyl groups, (C1-C6) straight or branched alkoxy groups, and -O-(CH2) m -COOR 32 or -(CH2) m -CH-(COOR 32 ) groups (where m is 1 or 2 and R 32 is selected from H or a (C1-C4) straight or branched chain alkyl group, and R 2 and R 5 are preferably independently selected from halogen, (C1-C6) straight or branched alkyl groups, and (C1-C6) straight or branched alkoxy groups; R 2 and R 5 are most preferably independently selected from halogen and (C1-C6) straight or branched alkoxy groups) are an object of the present invention.

[0032] Preferred photoinitiators of formula (V') are those having formula (1), (5), (6), (40), (44) or (45) set forth above, most preferably formula (1) or (5).

[0033] In a second alternative embodiment of formula (I), R 12 and R 13are not bonded to each other, so that the photoinitiator has the formula (VII): TIFF2026500735000022.tif75170 (in the above formula, R 2 , R 3 , R 4 , R 5 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , Y and y are as described above) It has.

[0034] Thus, in formula (VII): -R 11 , R 12 and R 13 are independently H, halogen, a (C1-C6) straight or branched alkyl group, a (C1-C6) straight or branched alkoxy group, pyrrolidin-1-yl, -L-Ph 1 group (wherein L is a single bond, CH2 or O, and Ph 1 are independently selected from the group consisting of halogen, (C1-C6) straight or branched alkyl groups, and (C1-C6) straight or branched alkoxy groups, and R 11 , R 12 and R 13 At least one of the is -L-Ph 1 is a group, and -R 14 and R 15 are independently H, halogen, a (C1-C6) straight or branched chain alkyl group, a (C1-C6) straight or branched chain alkoxy group, and -S-Ph-C(=O)-Ph.

[0035] The preferred embodiments described below can be considered alone or, where applicable, in combination with one another and are also applicable to formula (VII) and, where applicable, to formula (VIII) described below: -R 7 , R 8 , R9 and R 10 represents H, -R 4 is H, -R 3 is a halogen, a (C1-C6) straight or branched alkyl group, a (C1-C6) straight or branched alkoxy group, -O-(CH2) l -COOR 31 group and -(CH2) l -CH-(COOR 31 ) groups (where l is 1 or 2 and R 31 is selected from H or a (C1-C4) straight or branched chain alkyl group, and R 3 is preferably selected from halogen, (C1-C6) linear or branched alkyl groups and (C1-C6) linear or branched alkoxy groups, R 3 is most preferably a (C1-C6) linear or branched alkyl group, and R 2 , R 4 , R 7 , R 8 , R 9 and R 10 represents H, and R 5 is selected from H, halogen, (C1-C6) straight or branched alkyl group; or R 2 and R 5 is a halogen, a (C1-C6) straight or branched alkyl group, a (C1-C6) straight or branched alkoxy group, and -O-(CH2) m -COOR 32 or -(CH2) m -CH-(COOR 32 ) groups (where m is 1 or 2, and R 32 is independently selected from H or a (C1-C4) straight or branched chain alkyl group; R 2 and R 5 are preferably independently selected from halogen, (C1-C6) straight or branched alkyl groups, and (C1-C6) straight or branched alkoxy groups; R 2 and R 5 are most preferably independently selected from halogen and (C1-C6) straight or branched chain alkoxy groups, R3 , R 4 , R 7 , R 8 , R 9 and R 10 is H, -R 11 , R 12 and R 13 One of the groups is -L-Ph 1 group (where L is a single bond, CH2 or O, and Ph 1 is a phenyl group optionally substituted with one or more substituents selected from halogen, a (C-C) straight-chain or branched alkyl group, and a (C-C) straight-chain or branched alkoxy group; and R 11 , R 12 and R 13 the remaining two other groups are independently selected from H, halogen, a (C1-C6) straight or branched alkyl group, a (C1-C6) straight or branched alkoxy group, and pyrrolidin-1-yl; 11 , R 12 and R 13 The remaining two other groups among R are preferably selected from H, halogen, (C1-C6) linear or branched alkyl group, (C1-C6) linear or branched alkoxy group, 11 , R 12 and R 13 the remaining two other groups are most preferably selected from H and (C1-C6) linear or branched alkoxy groups; L is a single bond, and / or - Ph 1 is a phenyl group optionally substituted with one substituent selected from halogen, a (C1-C6) straight-chain or branched alkyl group, and a (C1-C6) straight-chain or branched alkoxy group, preferably a (C1-C6) straight-chain or branched alkoxy group, most preferably a methoxy group.

[0036] The photoinitiator may be represented by formula (12), (16), (26), (28), (32) and (33), most preferably by formula (26), (28), (32) and (33): TIFF2026500735000023.tif83170TIFF2026500735000024.tif81170TIFF2026500735000025.tif89170TIFF2026500735000026.tif70170TIFF2026500735000027.tif87170TIFF2026500735000028.tif70170 (wherein Y and y are as defined above) It is of the type.

[0037] In one embodiment, in formula (VII), L is a single bond and the photoinitiator is represented by formula (VIII): TIFF2026500735000029.tif85170 (in the above formula, -R 2 , R 3 , R 4 , R 5 , R 7 , R 8 , R 9 , R 10 , Y and y are as described above, and -R 20 and R 21 are independently selected from H, halogen, (C1-C6) straight or branched alkyl groups, (C1-C6) straight or branched alkoxy groups, preferably selected from H and (C1-C6) straight or branched alkoxy groups, and most preferably selected from H and OMe. It has.

[0038] Compounds of formula (VIII) are the subject of the present invention.

[0039] Preferably, in formula (VIII), R 20 are independently selected from H, halogen, (C1-C6) straight or branched alkyl groups, (C1-C6) straight or branched alkoxy groups, preferably selected from H and (C1-C6) straight or branched alkoxy groups, most preferably selected from H and OMe; R 21 is a (C1-C6) straight or branched alkoxy group, preferably OMe.

[0040] Preferred photoinitiators of formula (VIII) are those of formulae (26), (28), (32) and (33):

[0041] The photoinitiator of formula (I) is b) in the presence of an activating agent, a compound of formula (XXI): TIFF2026500735000030.tif73170 (in the above formula, R 2 , R 3 , R 4 , R 5 , R 7 , R 8 , R 9 , R 10 is as described above) by reacting a compound of formula (XXII): TIFF2026500735000031.tif38170 (in the above formula, R 11 , R 12 , R 13 , R 14 and R 15 is as described above) to form a photoinitiator of formula (I), thereby obtaining a photoinitiator of formula (I); c) Y y- If a photoinitiator of formula (I) is desired which is different from that obtained in step b), Y' y- as an anion, or Y' y- By carrying out an ion exchange reaction with an acid having a base of Y' y- is the Y described above y- Y has the same definition as y- obtaining a photoinitiator of formula (I) different from It can be prepared by a method comprising:

[0042] In step b), the activating agent is typically selected from trifluoromethanesulfonic anhydride ((CFSO)O,TfO), methanesulfonic anhydride ((CHSO)O), trifluoroacetic anhydride ((CFCO)O), acetic anhydride ((CHCO)O), aluminum chloride (AlCl) and phosphorus pentoxide (PO), and the activating agent is optionally used in combination with a strong Brønsted acid such as trifluoromethanesulfonic acid, methanesulfonic acid, trifluoroacetic acid or sulfuric acid. Preferably, the activating agent is trifluoromethanesulfonic anhydride ((CFSO)O,TfO).

[0043] Typically, step b) is carried out at a temperature of -60°C to -50°C.

[0044] The process may comprise, after step b), a step of purifying the compound of formula (I) obtained at the end of step b), for example by column chromatography.

[0045] By step b), Y y- When a photoinitiator of formula (I) is obtained in which the desired anion is Y, the method does not include step c). For example, when the activator is trifluoromethanesulfonic anhydride ((CFSO)O,TfO), the anion Y y- CF3SO3 - A photoinitiator of formula (I) is obtained, which is CF3SO3 - is the desired anion Y in formula (I) y- If so, step c) is not performed.

[0046] By step b), Y y- In the above example, if a photoinitiator of formula (I) is obtained in which Y is not the desired anion, the process comprises a step c) of ion exchange. y- CF3SO3 - If different from, for example, PF6 - is the desired Y' y- If so, step c) is typically carried out using sodium hexafluorophosphate or hexafluorophosphoric acid.

[0047] In step c), Y is used as the anion. y- The salts containing may be alkali metal salts, for example sodium or potassium salts.

[0048] Step c) is typically carried out in the presence of an organic solvent. Suitable organic solvents include chloroform, dichloromethane and acetic acid.

[0049] Scheme 1 below illustrates a method for preparing the photoinitiators of formula (I). TIFF2026500735000032.tif159170 Scheme 1

[0050] The method further comprises, before step b), reacting a compound of formula (XX): TIFF2026500735000033.tif73170 (in the above formula, R 2 , R 3 , R 4 , R 5 , R 7 , R 8 , R 9 , R 10 wherein R is as described above), to prepare a compound of formula (XXI). The oxidation is a selective oxidation of the compound of formula (XX) to the corresponding sulfoxide.

[0051] Step a) is generally carried out in the presence of an oxidizing agent typically selected from peroxy compounds (e.g., m-chloroperbenzoic acid (m-CPBA), peracetic acid, performic acid, and hydrogen peroxide), transition metal salts (such as ceric ammonium nitrate), and hypervalent halogen compounds (such as sodium hypochlorite), with the oxidizing agent preferably being m-CPBA.

[0052] Step a) may be carried out in the absence or presence of an organic solvent. Suitable organic solvents include chloroform, dichloromethane, acetonitrile or acetic acid.

[0053] Scheme 2 below illustrates a method for preparing compounds of formula (XXI). TIFF2026500735000034.tif83170 Scheme 2

[0054] The method may comprise, after step a), a step of purifying the compound of formula (XXI), for example by column chromatography.

[0055] The photoinitiator of formula (V') is q) Formula (XX'): TIFF2026500735000035.tif42170 (in the above formula, R 2 , R 3 , R 4 , R 5 , R 7 , R 8 , R 9 , R 10 is as described above) and a compound of formula (XXI'): TIFF2026500735000036.tif43170 (in the above formula, R 2 , R 3 , R 4 , R 5 , R 7 , R 8 , R 9 , R 10 is as described above), adding acetic anhydride and an acid to the mixture, thereby obtaining a photoinitiator of formula (V'); r)Y y- If a photoinitiator of formula (V') is desired which is different from that obtained in step q), Y' y- as an anion, or Y' y- By carrying out an ion exchange reaction with an acid having a base of Y' y- is the Y described above y- Y obtained in step q) y- obtaining a photoinitiator of formula (V) different from It can be prepared by a method comprising:

[0056] The process for the preparation of compounds of formula (V') is an object of the present invention.

[0057] The method comprises, before step q), reacting a compound of formula (XX'): TIFF2026500735000037.tif42170 (in the above formula, R 2 , R 3 , R 4 , R 5 , R 7 , R 8 , R 9 , R 10 is as described above) to obtain a compound of formula (XXI'): p) forming a compound of formula (I) of formula (II)

[0058] Most preferably, the amount of oxidizing agent used in step p) is adjusted so that step p) results in a mixture containing both the compound of formula (XXI') and the compound of formula (XX'), which mixture can be used as the mixture in step p) without isolating the compounds of formula (XXI') and (XX').

[0059] The oxidation in step p) is preferably carried out using CH3CO3H as the oxidizing agent, generally in an organic solvent such as dichloromethane. Typically, step p) is carried out at a temperature between 10°C and 30°C. Step p) may include a sub-step of quenching, for example with aqueous Na2SO3.

[0060] Step q) is generally carried out in the presence of acetic anhydride and a mineral acid, preferably sulfuric acid. Typically, step q) is carried out at a starting temperature of 0° C. to 5° C., and the reaction mixture is then warmed to ambient temperature (about 20° C.). After step q), the method may comprise a step q') of washing the reaction mixture obtained at the end of step q) with an aqueous solution, typically water.

[0061] Process q) Y y- When a photoinitiator of formula (V') is obtained in which Y is the desired anion, the method does not include step r). For example, when the acid is H2SO4, Y y- HSO4 - A photoinitiator of formula (V') is obtained, which is - is the desired anion Y y-If so, then step r) is not performed.

[0062] Process q) Y y- If a photoinitiator of formula (V') is obtained in which Y is not the desired anion, the process comprises a step r) of ion exchange. In the above example, the desired anion Y in formula (I) y- HSO4 - If different from, for example, PF6 - is the desired Y' y- If so, step r) is typically carried out with sodium hexafluorophosphate or hexafluorophosphoric acid.

[0063] Scheme 3 below illustrates a method for preparing a photoinitiator of formula (V'). TIFF2026500735000039.tif214170 Scheme 3

[0064] The composition used in the method comprises a cationically polymerizable compound.

[0065] The composition comprises a cationically polymerizable compound in addition to the photoinitiator of formula (I), and is therefore a curable composition.

[0066] The composition may comprise a mixture of cationically polymerizable compounds.

[0067] The term "cationically polymerizable compound" refers to a compound containing a polymerizable functional group, e.g., a carbon-carbon double bond substituted with a heterocyclic group or an electron-donating group, that polymerizes by a cationic mechanism. In the cationic polymerization mechanism, a cationic initiator forms a Bronsted or Lewis acid species that attaches to the cationically polymerizable compound, which then becomes reactive and initiates chain propagation by reaction with other cationically polymerizable compounds.

[0068] The cationically polymerizable compound can be selected from epoxy-functionalized compounds, oxetanes, oxolanes, cyclic acetals, cyclic lactones, thiiranes, thietanes, spiroorthoesters, ethylenically unsaturated compounds other than (meth)acrylates, derivatives thereof, and mixtures thereof, and is preferably selected from epoxy-functionalized compounds, oxetanes, polyols, and mixtures thereof.

[0069] The curable composition may comprise 5% to 99%, preferably 10% to 98%, and more preferably 20% to 97% by weight of one or more cationically polymerizable compounds, based on the total weight of the curable composition. When the composition comprises a mixture of cationically polymerizable compounds, the above weight percentages can be calculated using the weight of the mixture of cationically polymerizable compounds.

[0070] In a preferred embodiment, the cationically polymerizable compound comprises at least one compound selected from epoxides, oxetanes, oxolanes, cyclic acetals, cyclic lactones, thiiranes, thietanes, spiroorthoesters, vinyl ethers, and mixtures thereof.

[0071] In a most preferred embodiment, the cationically polymerizable compound comprises a cycloaliphatic epoxide and optionally an oxetane.

[0072] [Epoxy compounds] In the present invention, epoxy compounds are also referred to as epoxides or epoxy-functional compounds.

[0073] The epoxy-functional compounds can be monomers and / or oligomers.

[0074] Exemplary epoxy-functional compounds suitable for use include mono-epoxides, di-epoxides, and poly-epoxides (compounds containing three or more epoxy groups per molecule). Alicyclic polyglycidyl compounds and alicyclic polyepoxides are two classes of suitable epoxy-functional compounds. Such compounds contain two or more epoxide groups per molecule and may have an alicyclic ring structure containing the epoxide groups as side groups (pendant to the alicyclic ring) or a structure in which the epoxide group is part of the alicyclic ring structure.

[0075] An epoxy-functional compound can comprise, consist of, or consist essentially of at least one epoxy ether. As used herein, the term "epoxy ether" refers to a compound containing at least two epoxy groups and at least one ether linkage (the ether linkage being distinct from the cyclic ether linkage in the epoxy group). In particular, an epoxy ether can contain at least two epoxy groups and at least two ether linkages (the ether linkage being distinct from the cyclic ether linkage in the epoxy group).

[0076] The epoxy-functional compound may comprise, consist of, or consist essentially of at least one glycidyl ether. As used herein, the term "glycidyl ether" refers to a compound containing at least two glycidyl ether groups. As used herein, the term "glycidyl ether group" refers to a compound having the following formula (A): This refers to the base TIFF2026500735000040.tif24170.

[0077] In one embodiment, the epoxy compound can comprise, consist of, or consist essentially of at least one compound having two glycidyl ether groups, also known as a diglycidyl ether, hi another embodiment, the epoxy can comprise, consist of, or consist essentially of at least one compound having three glycidyl ether groups.

[0078] The epoxy may comprise, consist of, or consist essentially of at least one compound selected from aromatic epoxies, aliphatic epoxies, and mixtures thereof.

[0079] The epoxy may comprise, consist of, or consist essentially of at least one aromatic epoxy. As used herein, the term "aromatic epoxy" means a compound containing at least two epoxy groups linked together by an aromatic linker.

[0080] As used herein, the term "aromatic linker" refers to a linker that contains at least one aromatic ring, preferably at least two aromatic rings, and more preferably two or three aromatic rings. The term aromatic linker includes araliphatic linkers, i.e., linkers that contain both aromatic and non-aromatic portions.

[0081] The aromatic epoxy may be an aromatic glycidyl ether. As used herein, the term "aromatic glycidyl ether" refers to a compound containing at least two glycidyl ether groups linked together by an aromatic linker. Such compounds have the following formula (B): TIFF2026500735000041.tif27170 (wherein Ar is an aromatic linker; a is at least 2, preferably 2 to 10, more preferably 2 to 6. It can be expressed by:

[0082] The aromatic glycidyl ether may be a bisphenol-based glycidyl ether. As used herein, the term "bisphenol-based glycidyl ether" refers to a compound comprising at least two glycidyl ether groups linked together by an aromatic linker containing a moiety derived from a bisphenol. Such compounds may be represented by formula (B) above, where a is 2 and Ar is represented by the following formula (C): TIFF2026500735000042.tif30170 (wherein L is a linker; R1 and R2 are independently selected from alkyl, cycloalkyl, aryl, and halogen atoms; b and c are independently 0 to 4. is expressed by

[0083] In particular, L may be a linker selected from a bond, -CR3R4-, -C(=O)-, -SO-, -SO2-, -C(=CCl2)- and -CR5R6-Ph-CR7R8-; where: R3 and R4 are independently selected from H, alkyl, cycloalkyl, aryl, haloalkyl, and perfluoroalkyl, or R3 and R4 can form a ring together with the carbon atoms to which they are attached; R5, R6, R7 and R8 are independently selected from H, alkyl, cycloalkyl, aryl, haloalkyl and perfluoroalkyl; Ph is phenylene which may be substituted with one or more groups selected from alkyl, cycloalkyl, aryl and halogen atoms.

[0084] More specifically, Ar may be a residue of a bisphenol that does not contain an OH group. The compound according to formula (C) in which Ar is a residue of a bisphenol that does not contain an OH group may be called a bisphenol-based epoxy ether, preferably a bisphenol-based glycidyl ether. Examples of suitable bisphenols are bisphenol A, bisphenol AP, bisphenol AF, bisphenol B, bisphenol BP, bisphenol C, bisphenol C2, bisphenol F, bisphenol G, bisphenol M, bisphenol S, bisphenol P, bisphenol PH, bisphenol TMC, bisphenol Z, dinitrobisphenol A, tetrabromobisphenol A, and combinations thereof.

[0085] The epoxy-functional compound may comprise, consist of, or consist essentially of at least one aliphatic epoxy. As used herein, the term "aliphatic epoxy" means a compound containing at least two epoxy groups linked together by an aliphatic linker.

[0086] As used herein, the term "aliphatic linker" refers to a linker that does not contain any aromatic rings. It can be a linear or branched, cyclic or acyclic, saturated or unsaturated hydrocarbon linker. It can be optionally substituted with one or more groups selected from, for example, hydroxyl, halogen (Br, Cl, I, F), carbonyl, amine, carboxylic acid, -C(=O)-OR', -C(=O)-OC(=O)-R', where each R' is independently C1-C6 alkyl. It may be interrupted by one or more bonds selected from ether -(-O-), ester (-C(=O)-O- or -OC(=O)-), amide (-C(=O)-NH- or -NH-C(=O)-), urethane (-NH-C(=O)-O- or -OC(=O)-NH-), urea (-NH-C(=O)-NH-), carbonate (-OC(=O)-O-), and mixtures thereof.

[0087] The at least one aliphatic epoxy may be selected from aliphatic glycidyl ethers, epoxidized vegetable oils, and combinations thereof.

[0088] The aliphatic epoxy may be an aliphatic glycidyl ether. As used herein, the term "aliphatic glycidyl ether" refers to a compound containing at least two glycidyl ether groups linked together by an aliphatic linker. Such compounds have the following formula (D): TIFF2026500735000043.tif28170 (wherein Al is an aliphatic linker; d is at least 2, preferably 2 to 10, more preferably 2 to 6. It can be expressed as:

[0089] In particular, Al may be alkylene, optionally interrupted by one or more ether or ester bonds, or Al may correspond to a partially or fully hydrogenated derivative of the linker of formula (C).

[0090] More particularly, Al is a polyol P containing no OH groups. OH Suitable polyols P may be the residue of OHExamples include ethylene glycol, 1,2- or 1,3-propylene glycol, 1,2-, 1,3- or 1,4-butylene glycol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, 2-methyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 3,3-dimethyl-1,5-pentanediol, neopentyl glycol, 2,4-diethyl-1,5-pentanediol, cyclohexanediol, cyclohexane-1,4-dimethanol, norbornene dimethanol, norbornane dimethanol, tricyclodecanediol, tricyclodecane dimethanol, hydrogenated bisphenol A, B, F or S, trimethylolmethane, trimethylolethane, trimethylolpropane, di(trimethylolpropane), triethylolpropane, pentaerythritol, di(pentaerythritol), glycerol, di-, tri- or tetra- Included are glycerol, polyglycerol, di-, tri-, or tetraethylene glycol, di-, tri-, or tetrapropylene glycol, di-, tri-, or tetrabutylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, poly(ethylene glycol-co-propylene glycol), sugar alcohols (i.e., erythritol, threitol, arabitol, xylitol, ribitol, mannitol, sorbitol, galactitol, fucitol, or iditol), dianhydrohexitols (i.e., isosorbide, isomannide, isoidide), hydroxylated vegetable oils, tris(2-hydroxyethyl)isocyanurate, polybutadiene polyols, polyester polyols, polyether polyols, polyorganosiloxane polyols, polycarbonate polyols, and their alkoxylated (e.g., ethoxylated and / or propoxylated) derivatives, and derivatives obtained by ring-opening polymerization of ε-caprolactone initiated with one of the aforementioned polyols.

[0091] The epoxy compound has the following formula (E): TIFF2026500735000044.tif46170 (in the above formula, each R1 and R2 is independently selected from H and Me; L is the residue of a polyol, preferably (HO-CH2-)3C-CH2)2O; each a is independently 2 to 4, preferably 2 or 4; each b is independently 0 to 20, provided that at least one b is not 0; c is at least 3, preferably 3 to 10, particularly 3 to 8, more particularly 4 to 6 The alkoxylated cycloaliphatic epoxide may be an alkoxylated cycloaliphatic epoxide according to

[0092] The aliphatic epoxy compound can be an epoxidized vegetable oil.

[0093] As used herein, the term "epoxidized vegetable oil" refers to an unsaturated vegetable oil in which at least a portion of the carbon-carbon double bonds have been converted to epoxides. The unsaturated vegetable oil typically comprises one or more unsaturated diglycerides and / or triglycerides. The unsaturated diglycerides and triglycerides may correspond to diesters and triesters of glycerol and one or more fatty acids, at least a portion of which are unsaturated fatty acids. The fatty acids may be defined as monocarboxylic acids containing 4 to 32 carbon atoms, particularly 8 to 30 carbon atoms, and more particularly 10 to 28 carbon atoms. The unsaturated fatty acids correspond to fatty acids containing one or more carbon-carbon double bonds. Examples of unsaturated fatty acids include myristoleic acid, palmitoleic acid, sapienic acid, oleic acid, ricinoleic acid, elaidic acid, vaccenic acid, linoleic acid, linoelaidic acid, α-linolenic acid, arachidonic acid, eicosapentaenoic acid, erucic acid, docosahexaenoic acid, and combinations thereof. Unsaturated vegetable oils can be extracted from plants or trees, for example, from the seeds, fruits, flowers, bark, wood, stems, or leaves of plants or trees. Examples of suitable epoxidized vegetable oils include epoxidized soybean oil, epoxidized linseed oil, epoxidized castor oil, epoxidized corn oil, epoxidized cottonseed oil, epoxidized perilla oil, epoxidized safflower oil, epoxidized palm oil, epoxidized coconut oil, epoxidized rapeseed oil, epoxidized jatropha oil, epoxidized rubber seed oil, epoxidized tung oil, epoxidized tall oil, and combinations thereof.

[0094] Also suitable are linear or branched epoxidized polyenes, such as epoxidized polybutadiene and its copolymers, polyisoprene and its copolymers.

[0095] Examples of compounds in which the epoxide group forms part of an alicyclic ring system include bis(2,3-epoxycyclopentyl) ether; 2,3-epoxycyclopentyl glycidyl ether, 1,2-bis(2,3-epoxycyclopentyloxy)ethane; bis(4-hydroxycyclohexyl)methane diglycidyl ether, 2,2-bis(4-hydroxycyclohexyl)propane diglycidyl ether; 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate; 3,4-epoxy-6-methyl-cyclohexylmethyl-3,4-epoxycyclohexanecarboxylate; di(3,4-epoxy-6-methylcyclohexanecarboxylate); di(3,4-epoxycyclohexylmethyl)hexanedioate; di(3,4-epoxy-6-methylcyclohexylmethyl)hexanedioate; ethylene bis(3,4-epoxycyclohexane-carboxylate, ethanediol di(3,4-epoxycyclohexylmethyl)ether); vinylcyclohexene dioxide; dicyclopentadiene diepoxide; and 2-(3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy-)cyclohexane-1,3-dioxane.

[0096] Suitable illustrative mono-epoxides include glycidyl (meth)acrylate and (3,4-epoxycyclohexyl)methyl (meth)acrylate, as well as other mono-epoxide compounds containing epoxy and (meth)acrylate groups.

[0097] Suitable illustrative di-epoxides include diglycidyl ethers of dialcohols and diglycidyl esters of diacids, such as ethylene glycol diglycidyl ether, oligo- and polyethylene glycol diglycidyl ethers, propylene glycol diglycidyl ether, oligo- and polypropylene glycol diglycidyl ether, butanediol diglycidyl ether, alkoxylated (e.g., ethoxylated, propoxylated) butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, alkoxylated (e.g., ethoxylated, propoxylated) neopentyl glycol diglycidyl ether, hexanediol diglycidyl ether, alkoxylated (e.g., ethoxylated, propoxylated) butanediol diglycidyl ether, diglycidyl ethers of alkoxylated (e.g., ethoxylated, propoxylated) cyclohexanedimethanol diglycidyl ether, hydrogenated or non-hydrogenated bisphenol A diglycidyl ether (BADGE), hydrogenated or non-hydrogenated bisphenol F diglycidyl ether (BFDGE), alkoxylated (e.g., ethoxylated, propoxylated) bisphenols (such as bisphenol A or bisphenol F or their hydrogenated derivatives), diglycidyl esters of ortho-, iso-, or terephthalic acid, diglycidyl esters of tetrahydrophthalic acid, and diglycidyl esters of hexahydrophthalic acid.

[0098] Suitable illustrative poly-epoxides include glycidyl ethers of compounds having three or more hydroxyl groups, such as hexane-2,4,6-triol; glycerol; 1,1,1-trimethylolpropane; bistrimethylolpropane; pentaerythritol; sorbitol; and alkoxylated (e.g., ethoxylated, propoxylated) derivatives thereof, epoxy novolac resins, and the like.

[0099] The curable composition may, in certain embodiments, contain one or more polymerizable heterocyclic moiety-containing compounds containing one or more polymerizable ethylenically unsaturated sites (in addition to one or more epoxy groups), which may be provided by, for example, (meth)acrylate groups, (meth)acrylamide groups, vinyl groups, allyl groups, etc. Glycidyl methacrylate and glycidyl acrylate are specific examples of such polymerizable heterocyclic moiety-containing compounds. In calculating the relative amounts of oxetane and epoxy in the cationically curable compounds in the composition, these compounds are considered epoxies. Examples of suitable epoxy (meth)acrylates include the reaction products of acrylic or methacrylic acid, or mixtures thereof, with glycidyl ethers or esters.

[0100] [Oxetane compounds] In the present invention, the oxetane compound is also called an oxetane or an oxetane-functional compound.

[0101] The oxetanes can be monomeric and / or oligomeric.

[0102] Suitable illustrative oxetanes include oxetane itself and its substituted derivatives, provided that the substituents do not interfere with the desired reaction / polymerization / cure of the oxetane. The substituents can be, for example, alkyl groups, hydroxyalkyl groups, halo, haloalkyl groups, aryl groups, aralkyl groups, etc. The oxetane can be a mono-oxetane (a compound containing a single oxetane ring), a di-oxetane (a compound containing two oxetane rings), a tri-oxetane (a compound containing three oxetane rings), or an oxetane compound containing four or more oxetane rings. Examples of suitable oxetanes include, but are not limited to, oxetane, 3-ethyl-3-hydroxymethyloxetane, 1,4-bis[(3-ethyl-3-oxetanylmethoxy)methyl]benzene, 3-ethyl-3-phenoxymethyloxetane, 3-ethyl-3-{[(3-ethyloxetan-3-yl)methoxy]methyl}oxetane, 3,3-bis(chloromethyloxetane), 3-ethyl-3-[(phenylmethoxy)methyl]oxetane, 4,4'-bis(3-ethyl-3-oxetanyl)methoxymethyl]biphenyl, 3,3-bis(iodomethyl)oxetane, 3,3- Examples include bis(methoxymethyl)oxetane, 3,3-bis(phenoxymethyl)oxetane, 3-methyl-3-chloromethyloxetane, 3,3-bis(acetoxymethyl)oxetane, 3,3-bis(fluoromethyl)oxetane, 3,3-bis(bromomethyl)oxetane, 3,3-dimethyloxetane, 3-ethyl-3-[[(2-ethylhexyl)oxy]methyl]oxetane, bis[(3-ethyloxetan-3-yl)methoxy](dimethyl)silane, trimethylolpropane tris(3-ethyl-3-oxetanylmethyl)ether, and the like, and combinations thereof.

[0103] Examples of compounds having two or more oxetane rings that can be used include 3,7-bis(3-oxetanyl)-5-oxa-nonane, 3,3'-(1,3-(2-methyleneyl)propanediylbis(oxymethylene))bis-(3-ethyloxetane), 1,4-bis[(3-ethyl-3-oxetanylmethoxy)methyl]benzene, 1,2-bis[(3-ethyl-3-oxetanylmethoxy)methyl]ethane, 1,3-bis[(3-ethyl-3-oxetanylmethoxy)methyl]propane, ethylene glycol bis(3-ethyl -3-oxetanylmethyl) ether, dicyclopentenyl bis(3-ethyl-3-oxetanylmethyl) ether, triethylene glycol bis(3-ethyl-3-oxetanylmethyl) ether, tetraethylene glycol bis(3-ethyl-3-oxetanylmethyl) ether, tricyclodecanediyldimethylene(3-ethyl-3-oxetanylmethyl) ether, trimethylolpropane tris(3-ethyl-3-oxetanylmethyl) ether, 1,4-bis(3-ethyl-3-oxetanylmethoxy)butane, 1,6-bis(3-ethyl-3-oxetanylmethoxy)hexane, pentaerythritol tris(3-ethyl-3-oxetanylmethyl) ether, pentaerythritol tetrakis(3-ethyl-3-oxetanylmethyl) ether, polyethylene glycol bis(3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol hexakis(3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol pentakis(3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol tetrakis(3-ethyl-3-oxetanylmethyl) ether, caprolactone-modified dipentaerythritol hexakis(3-ethyl-3-oxetanylmethyl) ether, caprolactone-modified dipentaerythritol pentakis(3-ethyl-3-oxetanylmethyl) ether, ditrimethylolpropane tetrakis(3-ethyl-3-oxetanylmethyl) ether, EO-modified bisphenol A bis(3-ethyl-3-oxetanylmethyl) ether, PO-modified bisphenol A bis(3-ethyl-3-oxetanylmethyl) ether, EO-modified hydrogenated bisphenol A bis(3-ethyl-3-oxetanylmethyl) ether, PO-modified hydrogenated bisphenol A bis(3-ethyl-3-oxetanylmethyl) ether, EO-modified bisphenol F(3-ethyl-3-oxetanylmethyl) ether, and combinations thereof.

[0104] Additional examples of suitable oxetanes are described in the following patent documents, the disclosures of each of which are incorporated herein by reference in their entirety for all purposes: U.S. Patent Application Publication No. 2010 / 0222512A1, U.S. Patent No. 3,835,003, U.S. Patent No. 5,750,590, U.S. Patent No. 5,674,922, U.S. Patent No. 5,981,616, U.S. Patent No. 6,469,108, U.S. Patent No. 6,015,914, and U.S. Patent No. 8,377,623. Suitable oxetanes are commercially available, such as those sold by Toagosei Co., Ltd. under the trade names OXT-221, OXT-121, OXT-101, OXT-212, OXT-211, CHOX, OX-SC, and PNOX-1009.

[0105] Also suitable are oxetanes that also contain one or more polymerizable moieties of ethylenic unsaturation, which may be provided by (meth)acrylate groups, (meth)acrylamide groups, vinyl groups, allyl groups, etc. 3-Ethyl-3-(methacryloyloxy)methyloxetane or (3-ethyloxetan-3-yl)methyl acrylate are specific examples of such compounds. These compounds are included in the calculation of the amount of oxetane in the curable composition.

[0106] The curable composition may also contain compounds containing two or more different types of polymerizable heterocycles. For example, the compound may contain one or more oxetane rings and one or more epoxy rings (3-[(oxiranylmethoxy)methyl]oxetane is one example of such a compound). These compounds are included as compounds containing both epoxy and oxetane in calculating the relative amount of oxetane based on the total amount of oxetane- and epoxy-functional compounds in the composition.

[0107] [Other cationically curable compounds] In addition to the oxetane-functional and epoxy-functional compounds, other cationically curable compounds may be included in the composition. Non-limiting examples of such compounds include compounds with free hydroxyl groups. The total weight of the cationically curable compounds, including epoxides, oxetanes, and free hydroxyl components (e.g., hydroxyl groups from SpeedCure S130, OH from alcohols, polyols, and OH from (meth)acrylates, etc.), should constitute 100% of the weight of the cationic system of the composition.

[0108] Thus, polyols may optionally be included in the curable composition. As used herein, the term "polymer polyol" refers to a polymer having two or more primary, secondary, or tertiary alcohol groups per molecule. As used herein, the term "non-polymer polyol" refers to a non-polymeric compound having two or more hydroxyl groups per molecule. In the context of the present invention, the term "polymer" refers to a compound containing five or more repeating units per molecule, and the term "non-polymeric compound" refers to a compound containing up to four repeating units per molecule (hence, both oligomeric and monomeric compounds containing two to four repeating units per molecule). For example, ethylene glycol, diethylene glycol, triethylene glycol, and tetraethylene glycol are all examples of non-polymeric polyols, while polyethylene glycol containing five or more oxyalkylene repeating units is an example of a polymeric polyol.

[0109] Preferably, the hydroxyl groups are primary and / or secondary hydroxyl groups. When the polyol is a polymer polyol, in certain embodiments, the hydroxyl groups may be located at the terminal ends of the polymer. However, the hydroxyl groups may also be located along the main chain of the polymer, or as side chains or pendant groups to the main chain of the polymer. The polymer portion of the polymer polyol may be composed of multiple repeating units such as oxyalkylene units, ester units, carbonate units, acrylic units, alkylene units, etc., or combinations thereof.

[0110] According to certain embodiments, the polymer polyol has the following structure: HO-R9-OH where R9 is a polyether (e.g., polyoxyalkylene), polycarbonate, polydiene, polyorganosiloxane, or polyester chain or linker. It can be expressed as:

[0111] Particularly preferred polymer polyols include polyether diols and polyester diols. Suitable polyether diols include, for example, polytetramethylene glycol (a hydroxyl-functionalized polymer of tetrahydrofuran) and polyethylene glycol (a hydroxyl-functionalized polymer of ethylene oxide). Suitable polyester diols include, for example, poly(caprolactone), poly(lactide), poly(alkylene glycol adipate), and poly(alkylene glycol succinate).

[0112] Other types of polymer polyols potentially useful in the present invention include polycarbonate polyols, polyorganosiloxane polyols (e.g., polydimethylsiloxane diols or polyols), and polydiene polyols (e.g., polybutadiene diols or polyols, including fully or partially hydrogenated polydiene polyols).

[0113] The molecular weight of the polymer polyol can be varied as needed or desired to achieve specific properties in the cured composition obtained by curing the curable composition. For example, the number average molecular weight of the polymer polyol can be at least 300, at least 350, or at least 400 g / mol. In other embodiments, the polymer polyol can have a number average molecular weight of 5000 g / mol or less, 4500 g / mol or less, or 4000 g / mol or less. For example, the polymer polyol can have a number average molecular weight of 250 to 5000 g / mol, 300 to 4500 g / mol, or 350 to 4000 g / mol.

[0114] According to certain embodiments of the present invention, the polyol has the following structure: HO-R9-OH wherein R9 is a divalent non-polymeric aliphatic moiety optionally containing one or more heteroatoms (e.g., O, N, S, and / or halogens). It can be expressed as:

[0115] In certain embodiments of the invention, the diol is or includes a hydrogenated dimer fatty acid (often referred to as a "dimer diol"), a non-polymeric polyol that is a diol obtained by dimerizing one or more unsaturated fatty acids, such as oleic acid or linoleic acid, followed by hydrogenation to convert the carboxylic acid groups to hydroxyl groups. Pripol® 2033 (a product sold by Croda) is an example of a suitable commercially available hydrogenated dimer fatty acid.

[0116] Other types of suitable non-polymeric polyols include, but are not limited to, C2-C12 aliphatic polyols, diols, and their oligomers (containing up to four oxyalkylene repeat units). The aliphatic polyols or diols can be linear, branched, or cyclic in structure, and the hydroxyl groups can be both primary, both secondary, or one or more of each type (e.g., one primary and one secondary hydroxyl group).

[0117] Examples of suitable C2-C12 aliphatic diols include, but are not limited to, ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, 2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,2-dimethyl-1,3-propanediol, 2,2,4-trimethyl-1,5-pentanediol, and 2-methyl-2-ethyl-1,3-propanediol, and oligomers thereof containing up to four oxyalkylene repeat units.

[0118] When present, the optional at least one polyol may be selected from ethylene glycol, propylene glycol, 1,3-propanediol, 1,2-, 1,3-, or 1,4-butanediol, 2-methyl-1,3-propanediol (MPDiol), neopentyl glycol, alkoxylated derivatives thereof, polyether diols, polyester diols, polycarbonate diols, and combinations thereof.

[0119] Aliphatic diols (including linear, branched, or cyclic structures) can be ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, 1,3-butanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, etc., and their short-chain oligomers (containing up to four oxyalkylene repeat units). Typically, the hydroxyl groups in such aliphatic diols are primary or secondary hydroxyl groups, which readily react with the diisocyanates used to prepare the inherently reactive urethane acrylate oligomers.

[0120] The polyol may be selected from ethylene glycol, propylene glycol, 1,3-propanediol, 1,2, 1,3, or 1,4 butanediol, 2-methyl-1,3-propanediol (MPDiol), neopentyl glycol, alkoxylated derivatives thereof, polyether diols, polyester diols, or polysiloxane diols, and combinations thereof.

[0121] The cationically curable compound can also be, for example, a cyclic ether compound, a cyclic lactone compound, a cyclic acetal compound, a cyclic thioether compound, a spiroorthoester compound, or a vinyl ether compound.

[0122] [Free radical / cation hybrid composition] The composition may be a free radical / cationic hybrid composition, ie, a composition that is cured by both free radical and cationic polymerization.

[0123] The composition may therefore further comprise a radically polymerizable compound and optionally a radical photoinitiator.

[0124] Preferably, the radically polymerizable compound comprises at least one ethylenically unsaturated compound, preferably a (meth)acrylate-functionalized compound.

[0125] As used herein, the term "(meth)acrylate-functionalized compound" refers to a monomer containing a (meth)acrylate group, particularly an acrylate group. Here, the term "(meth)acrylate-functionalized compound" includes those containing more than one (meth)acrylate group, such as 2, 3, 4, 5, or 6 (meth)acrylate groups, commonly referred to as "oligomers" containing (meth)acrylate groups. The term "(meth)acrylate group" includes acrylate groups (-O-CO-CH=CH2) and methacrylate groups (-O-CO-C(CH3)=CH2). Preferably, the (meth)acrylate-functionalized compound does not contain any amino groups. As used herein, the term "amino group" refers to a primary, secondary, or tertiary amine group and does not include other types of nitrogen-containing groups, such as amide, carbamate (urethane), urea, or sulfonamide groups.

[0126] The (meth)acrylate-functionalized compound may have a molecular weight of less than 600 g / mol, in particular from 100 to 550 g / mol, more particularly from 200 to 500 g / mol.

[0127] The curable composition may comprise 5% to 95% by weight, preferably 8% to 90%, more preferably 10% to 80%, and most preferably 15% to 75% by weight, of one or more ethylenically unsaturated compounds, based on the total weight of the curable composition. If the composition comprises a mixture of ethylenically unsaturated compounds, the above weight percentages may be calculated using the weight of the mixture of ethylenically unsaturated compounds. In one embodiment, the curable composition may comprise 40% to 90%, 45% to 85%, 50% to 80%, or 50% to 75% by weight of (meth)acrylate-functional compounds, based on the total weight of the curable composition. Alternatively, the curable composition may comprise 5% to 50%, 10% to 45%, 15% to 40%, or 15% to 30% by weight of (meth)acrylate-functional compounds, based on the total weight of the curable composition.

[0128] Ethylenically unsaturated compounds suitable for use other than epoxy and oxetane-containing compounds include compounds containing at least one carbon-carbon double bond, particularly a carbon-carbon double bond capable of participating in a free radical reaction in which at least one carbon of the carbon-carbon double bond is covalently bonded to an atom, particularly a carbon atom, in a second molecule. Such a reaction can result in polymerization or curing, in which the ethylenically unsaturated compound becomes part of a polymerized matrix or polymer chain. In various embodiments of the present invention, the additional ethylenically unsaturated compound can contain one, two, three, four, five, or more carbon-carbon double bonds per molecule. Combinations of multiple ethylenically unsaturated compounds containing different numbers of carbon-carbon double bonds can be utilized in the curable compositions. The carbon-carbon double bond can be present as part of an α,β-unsaturated carbonyl moiety, for example, an α,β-unsaturated ester moiety such as an acrylate or methacrylate functional group, or an α,β-unsaturated amide moiety such as an acrylamide or methacrylamide functional group. The carbon-carbon double bond may also be present in the additional ethylenically unsaturated compound in the form of a vinyl group -CH=CH2 (e.g., an allyl group, -CH2-CH=CH2). Two or more different types of functional groups containing a carbon-carbon double bond may be present in the additional ethylenically unsaturated compound. For example, the ethylenically unsaturated compound may contain two or more functional groups selected from the group consisting of vinyl groups (including allyl groups), acrylate groups, methacrylate groups, acrylamide groups, methacrylamide groups, and combinations thereof.

[0129] Ethylenically unsaturated compounds that are suitable for use in the present invention include the following classes of compounds (where "functionality" refers to the number of (meth)acrylate functional groups per molecule, e.g., monofunctional = one (meth)acrylate group per molecule, difunctional = two (meth)acrylate groups per molecule): i) cyclic monofunctional (meth)acrylate compounds such as isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, 4-tert-butylcyclohexyl (meth)acrylate and their alkoxylated analogues; ii) linear or branched monofunctional (meth)acrylate compounds, such as isodecyl (meth)acrylate, ethoxyethoxyethyl (meth)acrylate, polyethylene mono(meth)acrylate, neopentyl glycol mono(meth)acrylate and their alkoxylated analogues, and hydroxyalkyl (meth)acrylates, such as caprolactone-based mono(meth)acrylates prepared by adding 1, 2, 3 or more moles of caprolactone to hydroxyethyl (meth)acrylate ("caprolactone adducts of hydroxyalkyl (meth)acrylates"); iii) cyclic difunctional (meth)acrylate compounds such as tricyclodecane dimethanol di(meth)acrylate, cyclohexane dimethanol di(meth)acrylate and their alkoxylated analogues; iv) linear or branched difunctional (meth)acrylate compounds, such as polyethylene di(meth)acrylate, neopentyl glycol di(meth)acrylate and their alkoxylated analogues; and v) Trifunctional (meth)acrylate compounds such as tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, trimethylolpropane tri(meth)acrylate and their alkoxylated analogues.

[0130] Illustrative examples of suitable ethylenically unsaturated compounds containing (meth)acrylate functionality include 1,2-, 1,3-, or 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, alkoxylated 1,6-hexanediol di(meth)acrylate, alkoxylated aliphatic di(meth)acrylates, alkoxylated neopentyl glycol di(meth)acrylate, cyclohexanedimethanol di(meth)acrylate, diethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, n-alkane (meth)acrylate, polyether di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, ethylene glycol di(meth)acrylate, 1,2- or 1,3-Propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyester di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, propoxylated neopentyl glycol diacrylate, tricyclodecane dimethanol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol penta / hexa(meth)acrylate, pentaerythritol (meth)acrylate esters, pentaerythritol tetra(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, alkoxylated trimethylolpropane tri(meth)acrylate, propoxylated glyceryl tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propoxylated glyceryl tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate (also known as tris((meth)acryloxyethyl)isocyanurate), 2(2-ethoxyethoxy)ethyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, 3,3,5-trimethylcyclohexyl (meth)acrylate, alkoxylated lauryl (meth)acrylate, alkoxylated phenol (meth)acrylate, alkoxylated tetrahydrofurfuryl (meth)acrylate, caprolactone (meth)acrylate, (meth)acryloxyethyl di(caprolactone), cyclic trimethylolpropane formal (meth)acrylate, alicyclic acrylate compounds, dicyclopentadienyl (meth)acrylate, diethylene glycol methyl ether (Meth)acrylate, ethoxylated (4) nonylphenol (meth)acrylate, ethoxylated nonylphenol (meth)acrylate, isobornyl (meth)acrylate, isodecyl (meth)acrylate, isooctyl (meth)acrylate, lauryl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, octyldecyl (meth)acrylate, stearyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, tridecyl (meth)acrylate acrylate, and / or triethylene glycol ethyl ether (meth)acrylate, t-butylcyclohexyl (meth)acrylate, alkyl (meth)acrylate, dicyclopentadiene di(meth)acrylate, alkoxylated nonylphenol (meth)acrylate, phenoxyethanol (meth)acrylate, octyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, tetradecyl (meth)acrylate, tridecyl (meth)acrylate, cetyl (meth)acrylate, hexadecyl (meth)acrylate, behenyl (meth)acrylate, diethylene glycol ethyl ether (meth)acrylate, diethylene glycol butyl ether (meth)acrylate, triethylene glycol methyl ether (meth)acrylate, 1,12-dodecanediol di(meth)acrylate, tricyclodecane methanol mono(meth)acrylate, glycerol carbonate (meth)acrylate, and combinations thereof.

[0131] Suitable polyether (meth)acrylates include, but are not limited to, the condensation reaction products of acrylic acid or methacrylic acid, or a mixture thereof, with polyetherol, a polyether polyol. Suitable polyetherols can be linear or branched materials containing ether linkages and terminal hydroxyl groups. Polyetherols can be prepared by the ring-opening polymerization of cyclic ethers, such as tetrahydrofuran or alkylene oxides, with starter molecules. Suitable starter molecules include water, hydroxyl-functional materials, polyester polyols, and amines.

[0132] In certain embodiments, one or more urethane diacrylates can be used. For example, the curable composition can include one or more urethane diacrylates, including difunctional aromatic urethane acrylate oligomers, difunctional aliphatic urethane acrylate oligomers, and combinations thereof. In certain embodiments, difunctional aromatic urethane acrylate oligomers, such as those available from Sartomer USA, LLC (Exton, Pennsylvania) under the trade name CN9782, can be used as the one or more urethane diacrylates. In other embodiments, difunctional aliphatic urethane acrylate oligomers, such as those available from Sartomer USA, LLC under the trade name CN9023, can be used as the one or more urethane diacrylates. CN9782, CN9023, CN978, CN965, CN9031, CN8881, and CN8886, all available from Sartomer USA, LLC, can all be advantageously used as urethane diacrylates in the composition.

[0133] Suitable acrylic (meth)acrylate oligomers (often referred to in the art as "acrylic oligomers") include oligomers that can be described as materials having an oligomeric acrylic backbone that is functionalized with one or more (meth)acrylate groups (which can be at the terminus of the oligomer or pendant to the acrylic backbone). The acrylic backbone can be a homopolymer, random copolymer, or block copolymer of repeating units of an acrylic compound. The acrylic compound can be any (meth)acrylate, such as a C1-C6 alkyl (meth)acrylate, and functionalized (meth)acrylates, such as (meth)acrylates with hydroxyl, carboxylic acid, and / or epoxy groups. Acrylic (meth)acrylate oligomers can be prepared using any procedure known in the art, such as by oligomerizing a compound, at least a portion of which is functionalized with hydroxyl, carboxylic acid, and / or epoxy groups (e.g., hydroxyalkyl (meth)acrylate, (meth)acrylic acid, glycidyl (meth)acrylate), to obtain a functionalized oligomeric intermediate, which is then reacted with one or more (meth)acrylate-containing reactants to introduce the desired (meth)acrylate functional groups. Suitable acrylic (meth)acrylate oligomers are commercially available, for example, from Sartomer USA, LLC under the product names CN820, CN821, CN822, and CN823.

[0134] Suitable free (meth)acrylate oligomers include, for example, polyester (meth)acrylates, epoxy (meth)acrylates, polyether (meth)acrylates, polyurethane (meth)acrylates, acrylic (meth)acrylate oligomers, epoxy-functional (meth)acrylate oligomers, and combinations thereof.

[0135] According to certain embodiments, the curable composition comprises one or more ethylenically unsaturated compounds containing one or more hydroxyl groups per molecule. Examples of such hydroxyl group-containing ethylenically unsaturated compounds include, but are not limited to, caprolactone adducts of hydroxyalkyl (meth)acrylates (having the general formula HC=C(R)-C(=O)-OR). 1 -(OC(=O)-[(CH2)5] n Compounds corresponding to OH (where R = H, CH3, R 1 =C2-C4 alkylene, such as ethylene, propylene, butylene, and n=1-10, e.g., acryloxyethyl di(caprolactone), hydroxyalkyl (meth)acrylates, alkoxylated (e.g., ethoxylated and / or propoxylated) hydroxyalkyl (meth)acrylates (including mono(meth)acrylates of ethylene glycol and propylene glycol oligomers and polymers), and the like.

[0136] In addition to the above-described radically polymerizable compounds, in this embodiment, the composition includes a radical photoinitiator, particularly a radical photoinitiator with Norrish Type I activity and / or Norrish Type II activity, more particularly a radical photoinitiator with Norrish Type I activity. The radical photoinitiator does not conform to formula (I).

[0137] Non-limiting types of radical photoinitiators suitable for use in the curable compositions include, for example, benzoin, benzoin ether, acetophenone, α-hydroxyacetophenone, benzil, benzil ketal, phosphine oxide, acylphosphine oxide, α-hydroxyketone, phenyl glyoxylate, α-aminoketone, benzoyl formate, acylgermanyl compounds, polymeric derivatives thereof, and mixtures thereof, including, but not limited to, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, α-methylbenzoin, α-phenylbenzoin, Michler's ketone, 1-hydroxyphenyl ketone, acetophenone, 2,2-diethyloxyacetophenone, benzil, α-hydroxyketone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,2-dimethoxy-1,2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4- (methylthio)phenyl]-2-morpholinopropanone, 2-hydroxy-2-methyl-1-phenylpropanone, oligomeric α-hydroxyketones, benzoylphosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, ethyl (2,4,6-trimethylbenzoyl)phenylphosphinate, anisoin, benzoin isobutyl ether, 4-benzoylbiphenyl, 2-benzyl-2-(dimethylamino)-4'-morpholinobutyrophenone, 4,4'-dimethylbenzyl, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide / 2-hydroxy-2-methylpropiophenone 50 / 50 blend, 4'-ethoxyacetophenone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 3'-hydroxyacetophenone, 4'-hydroxyacetophenone, methylbenzoyl formate, 4'-phenoxyacetophenone, polymeric derivatives thereof, and combinations thereof.

[0138] Preferred radical photoinitiators are acetophenone, α-hydroxyacetophenone, phosphine oxides and acylphosphine oxides, more preferably acetophenone and acylphosphine oxides.

[0139] In particular, the radical photoinitiator may be selected from acetophenones such as SpeedCure® BKL (2,2-dimethoxy-1,2-phenylacetophenone); acylphosphine oxides such as SpeedCure® XKM (ethylphenyl(2,4,6-trimethylbenzoyl)phosphineate), SpeedCure® BPO (phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide), SpeedCure® TPO (2,4,6-trimethylbenzoyldiphenylphosphine oxide) or SpeedCure® TPO-L (ethyl(2,4,6-trimethylbenzoyl)phenylphosphineate); and mixtures thereof.

[0140] The amount of radical photoinitiator can vary depending on the radical photoinitiator selected, the amount and type of polymerizable species present in the curable composition, the radiation source and radiation conditions used, and other factors. Typically, however, the amount of radical photoinitiator can be 0% to 10%, e.g., 0.05% to 10%, particularly 0.1% to 5%, and more particularly 0.5% to 2%, by weight of the radical photoinitiator, based on the total weight of the curable composition. For example, the amount of radical photoinitiator can be 0.01% to 5%, 0.02% to 3%, 0.05% to 2%, 0.1% to 1.5%, or 0.2% to 1% by weight, based on the total weight of the curable composition. In another example, the amount of radical photoinitiator can be 1% to 5%, 1.5% to 5%, 2% to 5%, 2.5% to 5%, or 3% to 5% by weight, based on the total weight of the curable composition.

[0141] [Filler] The curable composition may include at least one filler, such as at least one opaque filler that is insoluble in the other components of the photocurable composition. In particular, such fillers are insoluble in the curable composition. Furthermore, it is preferred that the at least one filler is insoluble in the solid resin matrix formed by curing the curable resin composition. The use of one or more fillers that are insoluble in the cured resin matrix allows for the preparation of composite materials from the curable composition of the present invention.

[0142] The filler can be in any suitable shape or form. For example, the filler can be in the form of a powder, beads, microspheres, particles, granules, wires, fibers, or combinations thereof. In particulate form, the particles can be spherical, flat, irregular, or elongated. For example, high aspect ratio particulate fillers can be utilized. Hollow as well as solid fillers are useful in the present invention. According to various embodiments of the present invention, the filler can have an aspect ratio (i.e., the ratio of the length of an individual filler element, such as a particle or fiber, to the width of that individual filler element) of 1:1 or greater, e.g., greater than 1:1, at least 2:1, at least 3:1, at least 5:1, at least 10:1, at least 100:1, at least 1000:1, at least 10000:1, at least 100,000:1, at least 500,000:1, at least 1,000,000:1, or more (i.e., a virtually infinite aspect ratio). According to other embodiments, the filler can have an aspect ratio of 2:1 or less, 3:1 or less, 5:1 or less, 10:1 or less, 100:1 or less, 1000:1 or less, 10000:1 or less, 100000:1 or less, 500000:1 or less, or 1000000:1 or less.

[0143] The surface of the filler can be modified according to any method or technique known in the art, including, but not limited to, sizing (e.g., coating with one or more organic substances), silylation, oxidation, functionalization, neutralization, acidification, other chemical modifications, and the like, and combinations thereof.

[0144] The chemical nature of the filler can be varied and selected as needed to impart desired properties or characteristics to the product obtained upon curing of the photocurable composition. For example, the filler can be inorganic or organic in nature. Organic / inorganic hybrid fillers can also be used. Carbon-based fillers (e.g., carbon fiber, carbon black, carbon nanotubes) and mineral fillers can be used. In particularly preferred embodiments of the present invention, one or more fibrous fillers (i.e., fillers in the form of fibers) can be utilized. Suitable exemplary fibrous fillers include carbon fibers (often referred to as graphite fibers), glass fibers, silicon carbide fillers, boron fibers, alumina fibers, polymer fibers (e.g., aramid fibers), metal fibers, natural fibers (e.g., fibers derived from plant sources), and combinations thereof. The fibers can be of natural or synthetic origin. Any of the following types of fibers can be used: short fibers (less than 10 mm in length), chopped fibers, long fibers (at least 10 mm in length), continuous fibers, woven continuous fibers, nonwoven continuous fibers, woven fiber mats, nonwoven fiber mats (e.g., random fiber mats), biaxial mats, unidirectional mats, continuous strands, unidirectional fibers, fiber tows, fiber wovens, braided fibers, knitted fibers, etc., and combinations thereof. Typically, suitable fibers have a diameter of about 2 to about 20 microns, e.g., about 5 to about 10 microns. Hollow as well as solid fibers can be used; the fiber cross-sections can be circular or irregular.

[0145] Examples of other types of fillers that can be used in the hardenable composition include clays (including organically modified clays and nanoclays), bentonite, silicates (e.g., magnesium silicate, talc, calcium silicate, wollastonite), metal oxides (e.g., zinc oxide, titanium dioxide, alumina), carbonates (e.g., calcium carbonate), mica, zeolites, talc, sulfates (e.g., calcium sulfate), and the like, and combinations thereof.

[0146] In one embodiment, the curable composition is not opaque but contains a relatively high loading of one or more fillers capable of scattering light irradiated onto the photocurable composition. For example, light scattering can occur when the refractive index of the filler differs from the refractive index of the non-filler portion of the curable composition (which, prior to curing, is typically a liquid comprising the photocurable compound, the photoinitiator system, and, optionally, other non-filler additives). Such fillers can include, for example, glass fillers (e.g., glass fibers) and transparent polymer fillers. In such embodiments, the curable composition can contain at least 20%, at least 30%, or at least 40% by weight of such light-scattering fillers, based on the total weight of the curable composition.

[0147] [solvent] Advantageously, the curable composition can be formulated to be solvent-free, i.e., free of any non-reactive volatile materials. However, in certain other embodiments of the present invention, the curable composition can include one or more solvents, particularly one or more organic solvents, which can be non-reactive organic solvents. In various embodiments, the solvent can be relatively volatile, e.g., having a boiling point at atmospheric pressure of 150°C or less. In other embodiments, the solvent can have a boiling point at atmospheric pressure of at least 40°C.

[0148] The solvent can be selected so that it can solubilize one or more components of the curable composition and / or adjust the viscosity or other rheological properties of the curable composition.

[0149] However, the curable composition can alternatively be formulated to contain little or no non-reactive solvent, for example, less than 10%, or less than 5%, or even 0% non-reactive solvent, based on the total weight of the curable composition. Such solvent-free or low-solvent compositions can be formulated using a variety of ingredients, including, for example, low viscosity reactive diluents, selected to provide a curable composition with a viscosity low enough, even in the absence of solvent, that the curable composition can be easily applied to a substrate surface at an appropriate application temperature to form a relatively thin, uniform layer.

[0150] Suitable solvents may include, for example, organic solvents such as ketones; esters; carbonates; alcohols; aromatic solvents such as xylene, benzene, toluene, ethylbenzene, and the like; alkanes; glycol ethers; ethers; amides; and combinations thereof.

[0151] In various embodiments of the present invention, the curable compositions described herein are formulated to have a viscosity of less than 10,000 mPa·s (cP), or less than 5,000 mPa·s (cP), or less than 4,000 mPa·s (cP), or less than 3,000 mPa·s (cP), or less than 2,500 mPa·s (cP), or less than 2,000 mPa·s (cP), or less than 1,500 mPa·s (cP), or less than 1,000 mPa·s (cP), or even less than 500 mPa·s (cP), measured at 25° C. using a Brookfield Viscometer Model DV-II with a 27 spindle (spindle speed varies depending on viscosity, typically between 20 and 200 rpm). In advantageous embodiments of the present invention, the viscosity of the curable composition is between 200 and 1,000 cP at 25° C.

[0152] [Additives] The curable composition may optionally contain one or more additives in place of or in addition to the above components, including, but not limited to, free radical chain transfer agents, antioxidants, UV absorbers, light screeners, light stabilizers, foam suppressors, flow or leveling agents, colorants, pigments, dispersants (wetting agents), slip additives, plasticizers, thixotropic agents, anti-yellowing agents, matting agents, impact modifiers, thermoplastic resins such as acrylic resins that do not contain any free radically polymerizable functional groups, waxes, or various other additives, including additives conventionally utilized in coating, sealant, adhesive, molding, 3D printing, or ink technology.

[0153] In one embodiment, the curable composition comprises an anti-yellowing agent, preferably an anti-yellowing agent containing an amino group, e.g., an aminobenzoate group, or a thio group, e.g., an agent containing both a (phenylthio) group and a carboxylic acid group, or a mixture thereof. Most preferably, the anti-yellowing agent is selected from ethyl-4-(dimethylamino)benzoate, (phenylthio)acetic acid, and mixtures thereof.

[0154] According to a second object, the present invention relates to a curable composition comprising a cationically polymerizable compound and a photoinitiator of formula (I), preferably of formula (VIII) or (V'). All embodiments described above for the cationically polymerizable compound, the photoinitiator of formula (I), and the optional additional compounds apply.

[0155] According to a third object, the present invention relates to a cured product obtained according to the method described above. The cured product may be a 3D printed article, a coating, an ink, an adhesive, a molding composition, or a sealant.

[0156] The most preferred application is the use of the method for the preparation of 3D printed articles.

[0157] Therefore, according to a fourth object, the present invention relates to a method for preparing a 3D printed article, comprising the curing method described above.

[0158] Non-limiting examples of suitable 3D printing methods include stereolithography (SLA); digital light processing (DLP); liquid crystal device (LCD); inkjet head (or multi-jet) printing; continuous liquid interface manufacturing (CLIP); extrusion-type processes such as continuous fiber 3D printing and cast-in-motion 3D printing; and volumetric 3D printing. The fabrication method can be "layer-by-layer" or continuous. Liquids can be deposited, for example, in a container or by inkjet or gel deposition methods.

[0159] When stereolithography is performed on an oxygen-permeable build window, the CLIP procedure enables the production of articles using curable compositions by forming an oxygen-containing "dead zone," a thin, uncured layer of curable composition, between the surface of the cured article being produced and the window. Such processes use curable compositions whose cure (polymerization) is inhibited by the presence of molecular oxygen; such inhibition is typically observed, for example, in curable compositions that are curable by a free-radical mechanism. The desired dead zone thickness can be maintained by selecting various control parameters, such as the photon flux and the optical and cure properties of the curable composition. The CLIP process proceeds by projecting a continuous actinic (e.g., LED) image (which may be generated, for example, by a digital light processing imaging unit) through an oxygen-permeable actinic (e.g., LED)-transmitting window below a bath of curable composition maintained in liquid form. The liquid interface below the advancing (growing) article is maintained by the dead zone formed above the window. The curing article is continuously withdrawn from the bath of curable composition above the dead zone, and the bath can be replenished with additional amounts of curable composition to make up for the amount of curable composition that is incorporated into the growing article as it cures.

[0160] In another embodiment, the curable composition is dispensed by ejection from a printhead rather than dispensed from a reservoir. This type of process is commonly referred to as inkjet or multi-jet 3D printing. One or more UV curing sources mounted directly behind the inkjet printhead cure the curable composition immediately after application to the build surface substrate or a previously applied layer. This method allows the use of two or more printheads capable of applying different compositions to different areas of each layer. For example, compositions of different colors or different physical properties can be applied simultaneously to create 3D-printed parts with various compositions. In typical use, support material (which is later removed during post-processing) is deposited simultaneously with the composition used to create the desired 3D-printed part. The printhead can operate at temperatures from about 25°C to about 100°C. The viscosity of the curable composition is less than 30 mPa·s at the printhead operating temperature.

[0161] In one embodiment, a method for preparing a 3D printed article comprises: a) depositing a first layer of the composition described above onto a surface; b) at least partially curing the first layer according to the method described above to provide a cured layer; c) depositing a second layer of the composition onto the cured first layer; d) at least partially curing the second layer according to the method described above to provide a cured second layer adhered to the cured first layer; and e) repeating steps c) and d) as many times as desired to build a 3D printed article. Includes:

[0162] Before curing, the composition can be applied to a substrate surface by any known common method, such as spraying, knife coating, roller coating, casting, drum coating, dipping, jetting, extrusion, gel deposition, and combinations thereof. Indirect application using transfer methods can also be used. The substrate can be any commercially relevant substrate, for example, a high surface energy substrate or a low surface energy substrate, such as a metal substrate or a plastic substrate. The substrate can include metal, paper, cardboard, glass, polyolefins, thermoplastics such as polycarbonate, acrylonitrile butadiene styrene (ABS) and mixtures thereof, composites, wood, leather, and combinations thereof.

[0163] The method may include a further step f) comprising heating the three-dimensional article to a temperature effective to thermally cure the curable composition.

[0164] After a 3D article has been printed, it may be subjected to one or more post-treatment steps, which may be selected from one or more of the following steps: removal of the printed support structure, washing with water and / or organic solvents to remove residual resin, and post-curing using heat treatment and / or actinic radiation, either simultaneously or sequentially. Post-treatment steps may be used to convert a freshly printed article into a finished functional article ready for use in its intended application.

[0165] In one embodiment, a method for preparing a 3D printed article comprises: a) providing a carrier and an optically transparent member having a build surface, the carrier and the build surface defining a build area therebetween; b) filling the build area with the composition described above; c) continuously or intermittently curing a portion of the composition within the build region according to the method described above to form a cured composition; and d) continuously or intermittently advancing the carrier from the build surface to form a 3D printed article from the hardened composition. Includes:

[0166] The method may further include a post-curing step of heating or microwaving the 3D printed article.

[0167] The post-treatment steps described above can also be applied.

[0168] According to a fifth object, the present invention relates to a 3D printed article obtained by the method for preparing a 3D printed article described above. [Brief explanation of the drawings]

[0169] The following examples and figures illustrate the invention. [Figure 1] Acrylate cure conversion at 405 nm for 0.5% Speedcure TPO-L in the hybrid formulation is provided. [Figure 2] Epoxide cure conversion at 405 nm for 0.5% Speedcure TPO-L in the hybrid formulation is provided. [Figure 3] The acrylate cure conversion at 405 nm is provided with different radical photoinitiators or no radical photoinitiator in the hybrid formulation. [Figure 4] Epoxide cure conversion at 405 nm with different radical photoinitiators or no radical photoinitiator in the hybrid formulation is provided. [Figure 5] The total cationic cure conversion at 405 nm is provided with different radical photoinitiators or no radical photoinitiator in the hybrid formulation. [Figure 6] Provides epoxide cure conversion at 405 nm in cationic formulations. [Figure 7] Provides oxetane cure conversion at 405 nm in cationic formulations. [Figure 8] Provides the total cationic cure conversion in cationic formulations. [Figure 9]The UV spectra of four novel sulfonium salts are provided: Omnicat 550, Speedcure 992S (>99% active ingredient), and Speedcure 938. [Figure 10] 4 provides the cure conversion of acrylates or epoxides versus exposure time at 10 mW with a 405 nm LED. [Example]

[0170] Example 1: Preparation of photoinitiators of formula (I) 1.1. Preparation of intermediate compound of formula (XXI) (step a) Compounds of formula (XXI) were prepared according to the following general procedure 1. To a solution of diaryl sulfide of formula (XX) (1.64 mmol) in dichloromethane (10 mL) was slowly added m-CPBA (1.804 mmol) at 0 °C. The mixture was stirred at 0 °C for 4 hours, then gradually warmed to room temperature and stirred for 16 hours. Saturated aqueous sodium bicarbonate solution was added, and the aqueous layer was then extracted with dichloromethane (3 × 3 mL). The combined organic layers were washed with brine, dried over magnesium sulfate, filtered, and concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography (PE / AcOEt) to give diaryl sulfoxide compound of formula (XXI). TIFF2026500735000045.tif34170[4-(4-methylbenzene-1-sulfinyl)phenyl](phenyl)methanone Prepared from {4-[(4-methylphenyl)sulfanyl]phenyl}(phenyl)methanone using general procedure 1. 73% yield, white solid, mp 143-144 °C. 1 H-NMR(400MHz, CDCl3):7.86(d,J=8.2Hz,2H),7.78-7.74(m,4H),7.60(tt,J=7.3,1.4 Hz,1H),7.58(d,J=8.2Hz,2H),7.50-7.46(m,2H),7.29(d,J=8.2Hz,2H),2.38(s,3H). TIFF2026500735000046.tif331702-(propan-2-yl)-10λ 4 -Thioxanthene-9,10-dione Prepared from 2-(propan-2-yl)-9H-thioxanthen-9-one using general procedure 1. 54% yield, pale yellow solid, mp 68-70°C. 1 H-NMR(400MHz,CDCl3):8.37(dd,J=7.8,1.4Hz,1H),8.24(d,J=1.8Hz,1H),8.16(dd,J=8.0,1.1Hz,1H),8.09(d, J=8.2Hz,1H),7.85(td,J=7.6,1.4Hz,1H),7.74-7.70(m,2H),3.09(septet,J=6.9Hz,1H),1.33(d,J=6.9Hz,6H). TIFF2026500735000047.tif391701-Chloro-4-propoxy-10λ 4 -Thioxanthene-9,10-dione Prepared from 1-chloro-4-propoxy-9H-thioxanthen-9-one using general procedure 1. 61% yield, yellow solid, mp 165-166°C. 1 H-NMR(400MHz, CDCl3):8.20-8.15(m,1H),7.96-7.91(m,1H),7.77-7.70(m,2H),7.62(d,J=9 .2Hz,1H),7.18(d,J=8.7Hz,1H),4.21-4.10(m,2H),2.02-1.93(m,2H),1.15(t,J=7.6Hz,3H). TIFF2026500735000048.tif30170 Methyl [(9,10-dioxo-9,10-dihydro-10λ 4 -thioxanthen-2-yl)oxy]acetate Prepared from methyl [(9-oxo-9H-thioxanthen-2-yl)oxy]acetate using general procedure 1. 81% yield, pale yellow solid. 1H-NMR(400MHz,CDCl3):8.35(d,J=7.8Hz,1H),8.14(d,J=7.8Hz,1H),8.07(d,J=8.7Hz,1H),7.85(t,J=7.6H z,1H),7.78(d,J=2.3Hz,1H),7.71(t,J=7.8Hz,1H),7.42(dd,J=8.7,2.3Hz,1H),4.80(s,2H),3.82(s,3H). TIFF2026500735000049.tif371702,4-Diethyl-10λ 4 -Thioxanthene-9,10-dione Prepared from 2,4-diethyl-9H-thioxanthen-9-one using general procedure 1. 62% yield, yellow solid, mp 99-100°C. 1 H-NMR (400MHz, CDCl3):8.38(dd,J=7.8,1.4Hz,1H),8.13(d,J=1.8Hz,1H),8.05(dd,J=7.8,1.4Hz,1H),7.82(td,J=7.3,1.4Hz,1H),7. 74(td,J=7.3,1.4Hz,1H),7.48(d,J=1.8Hz,1H),3.35-3.18(m,2H),2.78(q,J=7.8Hz,2H),1.30(t,J=7.6Hz,3H),1.44(t,J=7.6Hz,3H). TIFF2026500735000050.tif35170 Chloro-10λ 4 -Thioxanthene-9,10-dione (mixture of 2- and 4-isomers) Speedcure CTX (2.467 g; 10.0 mmol) was added portionwise to trifluoroacetic acid (27 mL) with stirring. The resulting mixture was cooled to 0-5 °C, and 35.6% aqueous hydrogen peroxide (1.003 g; 10.5 mmol) was added dropwise over 10 min. The mixture was then warmed to 20 °C over 4.5 h. Complete conversion of the starting CTX was confirmed by TLC (eluent: petroleum ether / ethyl acetate 1:1). The reaction mixture is added to 250 mL of ice water and stirred for 2 hours. The solid product is filtered off and washed with water. The crude product is then collected, suspended in dichloromethane (50 mL), and the solution is evaporated to remove residual water. The crude product is purified by crystallization from petroleum ether / toluene. Yield: 2.165 g (82%). 1 H-NMR shows that the product is a mixture of the 2- and 4-isomers (63:37).

[0171] 1.2. Y y- PF6 - Preparation of the photoinitiator of formula (I) (steps b) and c) Step b): Compounds of formula (I) were prepared according to the following general procedure 2. The appropriate aromatic sulfoxide of formula (XXI) (0.312 mmol) was dissolved in anhydrous dichloromethane (2.8 mL), and the resulting solution was cooled to between -60°C and -50°C. Trifluoromethanesulfonic anhydride (0.3432 mmol), used as an activating agent, was then added to the solution, and the mixture was stirred at a temperature between -60°C and -50°C for 20 minutes. The appropriate aromatic compound of formula (XXII) (0.312 mmol) was added, and the mixture was allowed to warm gradually to room temperature over 15 hours. The solvent was removed under reduced pressure, and the residue was washed with diethyl ether (2 x 3 mL) to give the compound of formula (I), where Y y- is CF3SO3 - This gave a crude sulfonium trifluoromethanesulfonate salt intermediate of formula (I). Further purification was achieved by silica gel column chromatography (eluting with dichloromethane / methanol).

[0172] Process c): In the examples, the anion Y y- PF6 - It was desired to have a compound of formula (I) The solvent was removed under vacuum and the residue was dissolved in water (10 mL) at room temperature. A solution of sodium hexafluorophosphate (1.2 mol equivalents) in water (1 mL) was added, followed by chloroform (10 mL), and the mixture was stirred at room temperature overnight. The organic layer was separated and the aqueous phase was extracted with chloroform (2 x 5 mL). The solvent was evaporated and Y y- PF6 - Thus, a hexafluorophosphate sulfonium compound of formula (I) was obtained. TIFF2026500735000051.tif421709-Oxo-10-[9-oxo-7-(propan-2-yl)-9H-thioxanthen-2-yl]-2-(propan-2-yl)-9H-thioxanthen-10-ium hexafluorophosphate(1) 2-(propan-2-yl)-10λ using general procedure 2 4 Prepared from -thioxanthene-9,10-dione and 2-(propan-2-yl)-9H-thioxanthen-9-one. Yield 28%, orange solid. 1 H-NMR(400MHz,CDCl3):8.68-8.65(m,1H),8.55-8.50(m,2H),8.25-8.20(m,3H),8.14(d,J=8.2Hz,1H),8.01-7.99(m,2H),7.86-7.83(m,2H),7.5 5(dd,J=8.2,1.8Hz,1H),7.48(d,J=8.2Hz,1H),3.15(septet,J=6.9Hz,1H),2.99(septet,J=6.9Hz,1H),1.36-1.33(m,6H),1.25(d,J=6.9Hz,6H). FT-IR (ATR; cm -1 ):505(w),531(m),556(s),631(w),640(w),688(w),713(w),741(m),752(m),782(m),834(vs),875(w),1061(w),1126(w),1206 (w),1239(w),1265(w),1286(w),1300(w),1390(w),1416(w),1442(w),1472(w),1575(w),1590(w),1640(w),1671(w),2962(w). TOF MS ES+m / z 507.1Da (accurate mass 557.1444Da). TIFF2026500735000052.tif50170 (4-benzoylphenyl) (4-methylphenyl) [9-oxo-7-(propan-2-yl)-9H-thioxanthen-2-yl] sulfonium hexafluorophosphate (2) (Comparative Example) Prepared from [4-(4-methylbenzene-1-sulfinyl)phenyl](phenyl)methanone and 2-(propan-2-yl)-9H-thioxanthen-9-one using general procedure 2. 39% yield, orange solid. 1 H-NMR (400MHz, CDCl3):8.82(d,J=2.3Hz,1H),8.34(d,J=2.3Hz,1H),8.06-7.96(m,4H),7.81-7.79(m,3H ),7.74-7.72(m,2H),7.62-7.47(m,8H),3.04(septet,J=6.9Hz,1H),2.48(s,3H),1.30(d,J=6.9Hz,6H). FT-IR (ATR; cm -1 ):532(m),556(s),580(w),610(w),633(w),643(w),661(w),698(w),731 (w),747(w),782(m),830(vs),876(w),926(w),1012(w),1061(w),1075(w) ),1126(w),1189(w),1205(w),1274(m),1310(w),1317(w),1397(w),1416 (w),1448(w),1472(w),1579(w),1640(w),1660(w),2870(vw),2961(vw). TOF MS ES+m / z 557.2Da (accurate mass 557.1597Da). TIFF2026500735000053.tif63170 (4-Benzoylphenyl) (8-chloro-9-oxo-5-propoxy-9H-thioxanthen-2-yl) (4-methylphenyl) sulfonium hexafluorophosphate (3) (Comparative Example) Prepared from [4-(4-methylbenzene-1-sulfinyl)phenyl](phenyl)methanone and 1-chloro-4-propoxy-9H-thioxanthen-9-one. Yield: 54%. Yellow solid. 1 H-NMR(400MHz,CDCl3):8.64(J=2.3Hz,1H),8.07(dd,J=8.7,2.3Hz,1H),8.02(d,J =8.2Hz,2H),7.94(d,J=8.7Hz,1H),7.81-7.79(m,4H),7.72(d,J=8.3Hz,2H),7.60 -7.55(m,3H),7.51-7.48(m,2H),7.42(d,J=8.7Hz,1H),7.05(d,J=8.7Hz,1H),4.1 0(t,J=6.4Hz,2H),2.49(s,3H),1.91(sextet,J=7.3Hz,2H),1.11(t,J=7.8Hz,3H). FT-IR (ATR; cm- 1 ):508(w),528(w),556(s),633(w),652(w),662(m),698(m),732(w),748 (w),788(m),809(s),835(vs),876(w),926(w),958(w),1012(w),1063(w) ),1178(w),1189(w),1255(m),1275(m),1308(w),1397(w),1433(w),144 8(w),1457(w),1546(w),1577(w),1653(w),2877(w),2967(w),3068(w). TOF MS ES+m / z 607.1Da (accurate mass 607.1163Da). TIFF2026500735000054.tif64170 (4-Benzoylphenyl) (5,7-diethyl-9-oxo-9H-thioxanthen-2-yl) (4-methylphenyl) sulfonium hexafluorophosphate (4) (Comparative Example) Prepared from [4-(4-methylbenzene-1-sulfinyl)phenyl](phenyl)methanone and 2,4-diethyl-9H-thioxanthen-9-one using general procedure 2. 41% yield, orange solid. 1H-NMR(400MHz,CDCl3):8.81(d,J=2.8Hz,1H),8.20(d,J=1.8Hz,1H),8.03-8.01(m,3H),7.82-7.79(m,3H),7.75-7.73(m,2H),7.61-7 .55(m,4H),7.50-7.43(m,4H),2.86(q,J=7.3Hz,2H),2.75(q,J=7.3Hz,2H),2.48(s,3H),1.35(t,J=7.3Hz,3H),1.28(t,J=7.3Hz,3H). FT-IR (ATR; cm- 1 ):476(w),516(w),556(s),633(w),661(m),699(m),731(m),748(w),782(m),833(vs),876(w),926(w),1 059(w),1190(w),1275(w),1310(w),1397(w),1426(w),1447(w),1579(w),1639(w),1660(w),2967(vw). TOF MS ES+m / z 571.2Da (accurate mass 571.1760Da). TIFF2026500735000055.tif571701-Chloro-10-(8-chloro-9-oxo-5-propoxy-9H-thioxanthen-2-yl)-9-oxo-4-propoxy-9H-thioxanthen-10-ium hexafluorophosphate (5) 1-Chloro-4-propoxy-10λ using general procedure 2 4 Prepared from -thioxanthene-9,10-dione and 1-chloro-4-propoxy-9H-thioxanthen-9-one; yield 30%; yellow solid. 1H-NMR(400MHz,DMSO-d6):9.15(d,J=2.3Hz,1H),8.49-8.44(m,1H),8.22-8.17(m,1H ),8.09(d,J=9.2Hz,1H),8.06(d,J=9.2Hz,1H),8.02-7.94(m,3H),7.71(d,J=9.2Hz,1 H),7.62(d,J=9.2Hz,1H),7.43(d,J=8.7Hz,1H),4.23-4.08(m,4H),1.79(sextet,J= 7.3Hz, 2H), 1.68 (sextet, J = 6.9Hz, 2H), 1.02 (t, J = 7.8Hz, 3H), 0.93 (t, J = 7.3Hz, 3H). FT-IR (ATR; cm- 1 ):495(w),534(w),546(w),557(s),644(w),651(w),687(w),694(w),718(w),742(w) ,761(m),773(w),799(m),808(s),820(s),836(vs),882(w),935(w),975(w),1058(m) ,1176(w),1238m),1254(m),1265(m),1276(m),1289(w),1303(m),1394(w),1435(w), 1443(w),1549(w),1558(w),1571(w),1663(w),1683(w),2877(w),2959(w),3082(w). TOF MS ES+m / z 607.1Da (accurate mass 607.0566Da). TIFF2026500735000056.tif571702-(2-Methoxy-2-oxoethoxy)-10-[7-(2-methoxy-2-oxoethoxy)-9-oxo-9H-thioxanthen-2-yl]-9-oxo-9H-thioxanthen-10-ium hexafluorophosphate (6) Using general procedure 2, methyl [(9,10-dioxo-9,10-dihydro-10λ] 4 Prepared from methyl [(9-oxo-9H-thioxanthen-2-yl)oxy]acetate and methyl [(9-oxo-9H-thioxanthen-2-yl)oxy]acetate. Yield 34%, dark yellow solid. 1H-NMR (400MHz, acetone-d6):9.29(bs,1H),8.71(m,1H),8.41-8.35(m,2H),8.16-8.09(m,2H),8.04-7.95(m,3H),7.80(d ,J=9.2Hz,1H),7.75-7.68(m,2H),7.51(dd,J=8.7,2.8Hz,1H),5.12(s,2H),4.97(s,2H),3.784(s,3H),3.777(s,3H). FT-IR (ATR; cm- 1 ):526(m),556(s),591(w),606(w),632(w),640(w),680(w),700(w),750(m),780(m),837(vs),1059(m),1082(w),1122(w), 1167(w),1210(m),1300(w),1339(w),1421(w),1438(w),1475(w),1575(w),1589(w),1599(w),1634(w),1573(w),1748(w). TOF MS ES+m / z 599.1Da (accurate mass 599.0829Da). TIFF2026500735000057.tif571709-Oxo-10-(4-phenoxyphenyl)-2-(propan-2-yl)-9H-thioxanthen-10-ium hexafluorophosphate (12) 2-(propan-2-yl)-10λ using general procedure 2 4 Prepared from -thioxanthene-9,10-dione and diphenyl ether. Yield 41%, pale yellow semi-solid. Note: The product is a mixture of para and ortho isomers (approximately 4:1). Major isomer: 1H-NMR (300MHz, CDCl3):8.65-8.62(m,1H),8.48(d,J=1.9Hz,1H),8.14-8.10(m,1H),8.05(d,J=8.1Hz,1H),7.99-7.95(m,2H),7.83(dd,J=8. 7,1.9Hz,1H),7.68(d,J=9.3Hz,2H),7.44-7.38(m,2H),7.28-7.20(m,1H),7.07-7.00(m,4H),3.15(septet,J=6.8Hz,1H),1.37-1.34(m,6H). TOF MS ES+m / z 423.1Da (accurate mass 423.1413Da). TIFF2026500735000058.tif581701-Chloro-9-oxo-10-(4-phenoxyphenyl)-4-propoxy-9H-thioxanthen-10-ium hexafluorophosphate (16) 1-Chloro-4-propoxy-10λ using general procedure 2 4 Prepared from -thioxanthene-9,10-dione and diphenyl ether. Yield 30%, pale yellow solid. 1 H-NMR (300MHz, CDCl3):8.63-8.59(m,1H),8.43-8.40(m,1H),7.99-7.88(m,3H),7.73(d,J=8.7Hz,2H),7.43-7 .34(m,3H),7.27-7.23(m,1H),7.04-6.99(m,4H),4.30-4.20(m,2H),2.06-1.94(m,2H),1.04(t,J=7.5Hz,3H). TIFF2026500735000059.tif8617010-(4'-Methoxy[1,1'-biphenyl]-4-yl)-9-oxo-2-(propan-2-yl)-9H-thioxanthen-10-ium hexafluorophosphate (26) 2-(propan-2-yl)-10λ using general procedure 2 4 Prepared from -thioxanthene-9,10-dione and 4-methoxybiphenyl. Yield 16%, tan semi-solid. 1H-NMR(300MHz,CDCl3):8.66-8.61(m,1H),8.48(d,J=1.9Hz,1H),8.35-8.28(m,1H),8.23(d,J=8.7Hz,1H),7.99-7.93(m,2H),7.88-7.80 (m,3H),7.70(d,J=8.7Hz,2H),7.45(d,J=8.7Hz,2H),6.95(d,J=8.7Hz,2H),3.83(s,3H),3.14(septet,J=6.9Hz,1H),1.36-1.33(m,6H). TOF MS ES+m / z 437.2Da (accurate mass 437.1568Da). TIFF2026500735000060.tif6417010-(2',6-Dimethoxy[1,1'-biphenyl]-3-yl)-9-oxo-2-(propan-2-yl)-9H-thioxanthen-10-ium hexafluorophosphate (28) 2-(propan-2-yl)-10λ using general procedure 2 4 Prepared from -thioxanthene-9,10-dione and 2,2'-dimethoxy-1,1'-biphenyl. Yield: 21%, pale orange semi-solid. 1 H-NMR(300MHz, CDCl3):8.62-8.59(m,1H),8.45(d,J=1.9Hz,1H),8.14(dd,J =8.7,2.5Hz,1H),8.08-7.96(m,4H),7.83(dd,J=8.1,1.9Hz,1H),7.34-7.28 (m,1H),7.23-7.19(m,2H),7.11(dd,J=7.5,1.9Hz,1H),6.96-6.88(m,2H),3 .83(s,3H),3.56(s,3H),3.14(septet,J=6.9Hz,1H),1.34(d,J=6.9Hz,6H). TOF MS ES+m / z 467.2Da (accurate mass 467.1675Da). TIFF2026500735000061.tif721701-Chloro-10-(4'-methoxy[1,1'-biphenyl]-4-yl)-9-oxo-4-propoxy-9H-thioxanthen-10-ium hexafluorophosphate (32) 1-Chloro-4-propoxy-10λ using general procedure 2 4 Prepared from -thioxanthene-9,10-dione and 4-methoxybiphenyl. Yield: 25%, pale green semi-solid. 1 H-NMR(300MHz,CDCl3):8.46-8.43(m,1H),8.33-8.30(m,1H),7.99-7.91(m,3H),7.71(s,4H),7.46(d,J=8.7Hz,2H),7 .42(d,J=9.3Hz,1H),6.96(d,J=9.3Hz,2H),4.28-4.21(m,2H),3.84(s,3H),2.03-1.91(m,2H),1.02(t,J=7.5Hz,3H). TOF MS ES+m / z 487.1Da (accurate mass 487.1129Da). TIFF2026500735000062.tif581701-Chloro-10-(2',6-dimethoxy[1,1'-biphenyl]-3-yl)-9-oxo-4-propoxy-9H-thioxanthen-10-ium hexafluorophosphate (33) 1-Chloro-4-propoxy-10λ using general procedure 2 4 Prepared from -thioxanthene-9,10-dione and 2,2'-dimethoxy-1,1'-biphenyl. Yield: 12%, dark brown semi-solid. 1 H-NMR(300MHz,CDCl3):8.42-8.39(m,1H),8.23-8.20(m,1H),7.98-7.89(m ,4H),7.45(d,J=9.3Hz,1H),7.37-7.31(m,1H),7.27-7.26(m,1H),7.17(d,J =8.7Hz,1H),7.12(dd,J=7.5,1.9Hz,1H),6.98-6.91(m,2H),4.25(t,J=6.2 Hz,2H),3.82(s,3H),3.61(s,3H),2.00-1.88(m,2H),1.02(t,J=7.5Hz,3H). TOF MS ES+m / z 517.1Da (accurate mass 517.1235Da). TIFF2026500735000063.tif8617010-(5,7-diethyl-9-oxo-9H-thioxanthen-2-yl)-2,4-diethyl-9-oxo-9H-thioxanthen-10-ium hexafluorophosphate (40) 2,4-Diethyl-10λ using general procedure 2 4 Prepared from 9H-thioxanthene-9,10-dione and 2,4-diethyl-9H-thioxanthen-9-one. Yield 52%, yellow solid. 1 H-NMR(300MHz,CDCl3):8.59-8.56(m,1H),8.49-8.42(m,3H),8.30(d,J=1.9Hz,1H),8.20(d,J=1.9Hz,1 H),8.00-7.90(m,3H),7.69(d,J=1.9Hz,1H),7.45-7.40(m,1H),3.31-2.70(m,8H),1.42-1.24(m,12H). TOF MS ES+m / z 535.2Da (accurate mass 535.1760Da).

[0173] 1.3. Preparation of photoinitiators of formula (V') General Procedure 3 To a solution of diaryl sulfide of formula (XX') in dichloromethane, CH3CO3H (35%) was slowly added. The mixture was stirred at 15-20°C for 2 hours, and then quenched with aqueous Na2SO3. Without isolating the mixture, it was cooled to 0-4°C, and excess acetic anhydride and excess H2SO4 were added. The reaction mixture was then gradually warmed to room temperature and washed with water. In the examples, the anion Y y- PF6 - Compounds of formula (V') were desired. An aqueous solution of sodium hexafluorophosphate (1.2 mol equivalents) was added followed by MTBE and the mixture was stirred at room temperature. The precipitate was filtered and washed to give Y y- PF6 - Thus, a sulfonium hexafluorophosphate compound of formula (V') was obtained. TIFF2026500735000064.tif571701-Chloro-10-(8-chloro-9-oxo-5-propoxy-9H-thioxanthen-2-yl)-9-oxo-4-propoxy-9H-thioxanthen-10-ium hexafluorophosphate (5) Prepared from 1-chloro-4-propoxy-9H-thioxanthen-9-one using general procedure 3; 84% yield; yellow solid. The analysis is provided above. TIFF2026500735000065.tif42170Chloro-10-(chloro-9-oxo-9H-thioxanthen-2-yl)-9-oxo-9H-thioxanthen-10-ium hexafluorophosphate (50) (mixture of isomers) Speedcure CTX (1.2336 g; 5.0 mmol) and Chloro-10λ 4 1.3136 g (5.0 mmol) of 1,3-thioxanthene-9,10-dione (2- and 4-isomer mixture) was suspended in a mixture of acetic anhydride (6.0 mL) and dichloromethane (4.0 mL). The stirred mixture was cooled in ice water, and methanesulfonic acid (15.0 mL) was added dropwise over 5 minutes. The mixture was stirred under ice water cooling for 2 hours, and then stirred at 20°C for 60 hours in the dark. The dark red reaction mixture is added to a mixture of ice water (150 g) and dichloromethane (125 mL) and stirred vigorously at ambient temperature for 1 hour. The mixture is phase separated, and the organic phase is washed with water (50 mL), then separated and treated with a solution of potassium hexafluorophosphate (1.4726 g, 8.0 mmol) in water (20 mL). The biphasic mixture is vigorously stirred for 1.5 h and then partially evaporated to remove dichloromethane. The yellow-orange suspension is then diluted with water (100 mL), diisopropyl ether (75 mL) is added, and the mixture is vigorously stirred for 2 h and then filtered. The collected solid is suspended in diisopropyl ether (50 mL) and water (15 mL) and vigorously stirred for 16 h. The solid product is filtered off, washed with diisopropyl ether (50 mL), and dried under vacuum. Yield: 1.5247 g (48%); orange solid. FT-IR (ATR; cm- 1):1677(w),1639(w),1579(w),1453(vw),1439(w),1403(w),1395(w),1292(m),1264(w),1171(w),1143(vw),1 099(w),1057(w),838(vs),818(s),799(m),780(w),759(m),749(m),739(m),671(w),556(s),526(m),511(m). TOF MS ES+m / z 491.0Da (accurate mass 490.9729Da).

[0174] Example 2: Curing characteristics of the photoinitiator of Example 1 2.1. Curing performance at 365nm and 385nm The curing performance of each of the products prepared above was evaluated using real-time FT-IR measurements. The photoinitiator was dissolved in the cycloaliphatic epoxy resin UViCure S105 (available from Sartomer) at the indicated loading (wt%), coated on an FT-IR measurement plate, and irradiated with the indicated LED light source. During irradiation, the 900 cm corresponding to the epoxide ring was observed. -1 The polymerization rate and final reactive group conversion were quantified by monitoring the change in the relevant infrared absorption band around the photoinitiator. -1 cm -1 (denoted by) in acetonitrile, 10 -3 M or 10 -5 Quantification was performed using M concentration. TIFF2026500735000066.tif166170

[0175] 2.2. Curing performance at 405 nm The curing performance of each of the products prepared above was evaluated using real-time FT-IR measurements. The photoinitiators were dissolved in neat trimethylolpropane triacrylate (TMPTA; available from Sartomer as SR351) or in a 1:1 (w / w) mixture of TMPTA and UViCure S105 as indicated, coated onto an FT-IR measurement plate, laminated to prevent oxygen inhibition, and irradiated with the indicated LED light source. For the epoxy component, the 900 cm corresponding to the epoxide ring was used.-1 The polymerization rate and final reactive group conversion were quantified by monitoring the changes in the relevant infrared absorption bands around 1625 cm for the acrylate component. -1 The C=C stretching vibration band near TIFF2026500735000067.tif152170

[0176] 2.3. Belt curing performance at 365nm and 395nm The photoinitiator was dissolved in neat UViCure S105E resin or acrylate / epoxy hybrid resin (prepared by mixing 60 parts by weight of UViCure S105E, 15 parts by weight of UViCure S130, and 25 parts by weight of SR492; all products are available from Sartomer). Formulations were prepared by mixing all materials in the given proportions and stirring at 30–40°C until the sample was completely homogenous; the formulation was then allowed to cool to room temperature. For all experiments, formulations were cured at 6 μm and 24 μm film thicknesses on Leneta Form 3N-31 glossy finish paper using a belt-curing device; films were prepared using a K-bar. All films were then cured under an LED lamp at the given belt speed. The "deep section cure" for each formulation was assessed from the belt speed using the "thumb twist" test (pressing your thumb firmly on the coating while twisting it leaves no visible mark); the calculated cure speed (m / min) is shown. TIFF2026500735000068.tif77170TIFF2026500735000069.tif79170

[0177] These results demonstrate that the sulfonium salt photoinitiators of the present invention are effective photoinitiators for epoxy, acrylic, and hybrid resin formulations under LED lamp conditions.

[0178] In particular, photoinitiators 2 and 4 exhibit higher cure rates than photoinitiators known in the prior art, such as Omnicat BL 550. The belt cure results appear to show that photoinitiator 5 exhibits better cure speed than photoinitiator 1 at 80 m / min for the acrylate / epoxy hybrid resin at both 365 nm and 395 nm.

[0179] Photoinitiator 5 exhibits higher cure speeds than photoinitiators known in the prior art, such as Omnicat BL 550. Photoinitiators 26 and 32 exhibit higher cure rates than photoinitiators known in the prior art, such as Omnicat BL 550.

[0180] Example 3: Other Properties of the Photoinitiator of Example 1 3.1. Color Measurement A formulation containing photoinitiator and neat UViCure S105E resin was prepared as described in Example 2. TIFF2026500735000070.tif105170

[0181] 3.2. Solubility Data The solubilities of selected sulfonium salts in propylene carbonate at ambient temperature (20-25°C) were determined. TIFF2026500735000071.tif67170

[0182] 3.3. Thermal stability determined by DSC Formulations containing photoinitiators and neat UViCure S105E resin and / or TMPTA resin were prepared as described in Example 2. TIFF2026500735000072.tif85170TIFF2026500735000073.tif64170

[0183] 3.4. Transmittance data Samples were prepared at 0.01% w / v in propylene carbonate. TIFF2026500735000074.tif47170

[0184] 3.5. 6-Month Stability Study and Reference TIFF2026500735000075.tif117170

[0185] Example 4: Curing performance in cationic and hybrid formulations and 3D printability of hybrid systems 4.1. Materials and Construction TIFF2026500735000076.tif243170TIFF2026500735000077.tif232170TIFF2026500735000078.tif236170TIFF2026500735000079.tif91170

[0186] 4.2. Sample preparation and test methods TIFF2026500735000080.tif138170TIFF2026500735000081.tif213170TIFF20265007350 00082.tif168170TIFF2026500735000083.tif168170TIFF2026500735000084.tif183170 TIFF2026500735000085.tif183170TIFF2026500735000086.tif183170TIFF20265007350 00087.tif174170TIFF2026500735000088.tif174170TIFF2026500735000089.tif175170

[0187] Preparation of matrices and formulations in Tables 12-21 Matrix: A 1000 mL metal can was filled with the formulation matrix according to the proportions in Table 12. A 1000-1005 g mixture of each matrix sample was prepared and mixed in a mechanical mixer for approximately 1 hour at around 60°C until the solution became clear. Formulation: The photoinitiator and propylene carbonate were first added to a white FlackTek max50 jar, mixed by hand with a stainless steel spatula, placed in a 60°C oven for approximately 1 hour, and mixed again until clear. Next, a formulation matrix was added according to the proportions in Tables 13-21. A 51.25.5-52.60 g mixture of each sample was prepared and mixed for 3 minutes at 3000 RPM in a FlackTek Speedmixer. All jars were then placed in a 60°C oven for approximately 2 hours, removed, and immediately mixed for an additional 2 minutes until the solution was clear.

[0188] [FTIR Test] A Fourier transform infrared spectrometer (FTIR) equipped with an attenuated total reflectance (ATR) device was used. All polymerization kinetic measurements were performed using a Thermo Scientific Nicolet iS50 FT-IR spectrometer equipped with a standard DLaTGS detector. The lamp holder for the ART platform of the FTIR instrument was custom printed from Arkema's N3xtDimention® engineered resin N3D-TOUGH784 to ensure accurate mounting of the Digital Light Labs 365 nm lamp AccuCure ULM-2-365 or the 405 nm lamp AccuCure ULM-2-405. The lamp holder's bottom features a dry air channel, allowing for uniform air flow across the sample surface; the gas flow rate is controlled by a rotameter. The LED light was manually activated by the UV irradiation measurement system. The LED exposure was programmable in the AccuCure software. For measurements, 25 μL of liquid sample was placed in the center of the ATR crystal. A 3 mil thin film was prepared with a customized coating applicator (BYK 3 mil WFM, G1046). An LED lamp with a holder was placed on top of the ART platform. Then, an FTIR scan was initiated to first collect the liquid IR spectrum. 10 mW / cm 2 Each IR spectrum was collected for a specific exposure time with LED light. Measurement of acrylate conversion was performed at approximately 1727 cm -1The peak height below the reference peak was approximately 1407 cm -1 The acrylate peak of SR833S at approximately 790 cm -1 The epoxide peak of UviCure S105 at about 970 cm -1 The oxetane peak of UViCure S130 at 1100 cm was also measured. The ring opening of both the epoxide and the oxetane produced a C-O-C bond, resulting in a peak at approximately 1100 cm. -1 The growth of the COC IR peak height at 1100 cm was also monitored. -1 The growth rate of the peaks could be calculated to assess the overall cationic cure rate. The peak heights were determined using the same baseline, but at 600 cm. -1 and 1800cm -1 The two lowest points between were selected. The peak heights under the peak and above the baseline were then determined. The integration limits for the liquid and cured samples are not identical but are similar, especially for the reference peak.

[0189] For both the liquid and cured samples, the ratio of the acrylate peak height, the epoxide peak height, and the ring-opened peak heights of both the epoxide and oxetane to the reference peak height was quantified. The degree of cure or conversion or peak growth rate, expressed as the percentage of reacted acrylate or epoxide, or ring-opened epoxide and oxetane, was calculated from the following equation: Conversion rate (%) = [(R liq -R c )×100] / R liq Peak growth rate (%) = [(R c -R liq )×100] / R liq where R liq is the peak height ratio of the liquid sample, R c is the peak height ratio of the LED-cured sample. The resulting acrylate and epoxide conversions, or COC growth rates, are collected and listed in Tables 13-21 and plotted in Figures 1-8 and 10.

[0190] UV Vis spectrum measurement The UV-Vis spectrum of each sample was measured using a Shimadzu UV1800 spectrophotometer in a 1.0 cm optical path quartz cell in accordance with ASTM E169-04. The spectrum was scanned over the wavelength range of 450–200 nm. The measurement cell was filled with an acetonitrile solution containing 10 ppm of photoinitiator, and the absorbance value observed was adjusted to not exceed 1.0 in the desired spectral range.

[0191] Working curve measurement Working curve: 405nm, approximately 3mW / cm 2 Flashforge Hunter DLP printer, or 405nm approx. 12mW / cm 2 Printing was performed on a B9Creation B9 Core 550 DLP printer. Various energy doses were applied to a cross section of the build area (without the build platform in place) to cure individual squares or thin films. The thickness of each thin film was measured using a Mitutoyo low-load digital caliper and comparator stand to quantify cure depth. A plot of cure depth versus the logarithm of energy dose was used to determine the critical exposure dose (Ec, mJ / cm). 2 ) and penetration depth (D p , mil) was determined.

[0192] Preparation of tensile test parts Diagnostic components were printed on a 405nm B9 Core 550 DLP 3D printer at approximately 12mW / cm 2 The ASTM D638-14 Type IV tensile dogbone was designed in CAD software and exported to an STL file to enable 3D printing of the diagnostic part. The part was printed in the XY plane directly on the build platform without support structures, with a layer thickness of 50 microns. The amount of energy used per 50 micron layer was 50 mJ / cm for Ex17. 2 , 25mJ / cm for Ex18 2These energy levels were determined from working curve data to achieve a cure depth of 150 microns. Fine-tuning was performed through iterative experimentation to maximize printability and resolution.

[0193] The parts were post-cured in a Sprintray ProCure UV post-cure unit for 20 minutes per side. Irradiance measurements of the post-cure unit at various wavelengths, collected using an Ophir Starbright power meter in combination with a PD300RM-UV radiometer, are shown below. TIFF2026500735000090.tif31170After UV post-cure, samples were conditioned for 7 days according to ASTM D618-13-Procedure A before testing.

[0194] Mechanical testing of 3D printed articles: Samples were tested according to ASTM D638-14 using an Instron 5966 universal testing machine equipped with 5 kN wedge grips. A tensile rate of 5 mm / min was used, and a static axial clip-on extensometer was utilized to determine Young's modulus.

[0195] 4.3 Results and Discussion 4.3.1. Curing performance in hybrid systems The acrylates and epoxides at 405 nm, as listed in Table 13, are shown in the following Figures 1 and 2. Results shown for either high epoxide (HE) or low epoxide (LE) hybrid systems: 1) All of the new cationic photoinitiators showed better acrylate cure than Omnicat 550; 2) All of the new cationic photoinitiators showed better epoxide and total cationic cure than Speedcure 992. The epoxide cure of photoinitiators 5, 1, and 4 (comparative examples) was also better than Omnicat 550 and consistent with the control sample SC938 / CPTX.

[0196] The effect of different radical photoinitiators or no radical photoinitiator on acrylate, epoxide, and total cationic cure at 405 nm, as listed in Tables 13-18, is shown in the following Figures 3, 4, and 5.

[0197] Results shown for either high epoxide (HE) or low epoxide (LE) hybrid systems: 1) Both 5 and 4 (comparative examples) showed high acrylate cure with or without a radical photoinitiator. With the shorter wavelength radical initiator BKL or the low 405 nm absorption XKm, both 4 (comparative example) and CPTX-CPT were able to cure acrylates very well, similar to SC938 / CPTX, even without any radical initiator. 2) Both 5 and 4 (comparative examples) showed better epoxide cure and total cationic cure than Omnicat 550 and SC992, with or without a radical photoinitiator. Overall, both 5 and 4 (comparative examples) showed good performance in hybrid systems, consistent with SC938 / CPTX.

[0198] Under short wavelength LED irradiation such as 365 nm, these new cationic photoinitiators showed similar performance to SC938 / CPTX, Omnicat 550, and SC992, as listed in Tables 13-18.

[0199] 4.3.2. Curing performance in cationic systems The epoxide, oxetane and total cationic cure at 405 nm, as listed in Tables 19-21, are shown in the following Figures 6, 7 and 8.

[0200] Results shown for cationic systems: 1) All four novel cationic photoinitiators 2 (comparative), 4 (comparative), 1, and 5 exhibited better epoxide cure, oxetane cure, and overall cationic cure than Omnicat 550 and SC992. Among them, 5 and 1 performed slightly better than 2 (comparative) or 4 (comparative). Neither radical photoinitiator BKL nor TPO-L was able to promote cationic photopolymerization. In fact, the radical photoinitiators slowed the cationic cure, with TPO-L being the slowest.

[0201] At short wavelength LED exposures such as 365 nm, these new cationic photoinitiators performed very similarly to Omnicat 550 and SC938 / CPTX, and slightly better than SC992, as listed in Tables 19-21.

[0202] 4.3.3 3D printing suitability of hybrid systems UV Spectra: As shown in Figure 9, the UV spectra of the four novel sulfonium salts were compared with Omnicat 550, Speedcure 992S (>99% active ingredient), and Speedcure 938. At 405 nm, UV absorption decreased in the order 5 > 1 > 2 (comparative) ≈ 4 (comparative), all of which were significantly higher than Omnicat 550 and SC 992S. SC 938 had no absorption at wavelengths above 310 nm.

[0203] Formulations for 3D Printing at 405 nm: Exemplary hybrid systems were selected to evaluate the printability of both 5 and 4 (comparative example) compared to Omnicat 550 and SC992, as shown in Table 23. Working curve data was measured from a Flashforge Hunter DLP printer at 3.1 mW and 405 nm or a B9 Core 550 DLP printer at approximately 10 mW and 405 nm. TIFF2026500735000091.tif224170 Working curve film squares of each formulation were printed using a Flashforge Hunter DLP printer at 3.1 mW and 405 nm or a B9 Core 550 DLP printer at approximately 10 mW and 405 nm, and the print exposure conditions are listed in Table 23. As expected, both SC992 (Ctr10) and Omnicat 550 (Ctr11) failed to print even after the exposure time was exceeded. The two novel sulfonium salts printed well, and generally, low concentrations of 5 provided a lower Dp and higher Ec than 4 (comparative example) due to its higher absorption at 405 nm, as shown in Figure 9.

[0204] At a dry air flow rate of 10 LPM, both the acrylate and epoxide cures of formulations Ex17 and Ex18 cured well with a 10 mW 405 nm LED, as shown in Figure 10.

[0205] A series of tensile parts were successfully printed from Formulation Examples Ex17 and Ex18 using a B9 Core 550 DLP printer at approximately 10 mW and 405 nm, and the post-UV cured parts produced a range of desirable tensile property data, as listed in Table 23.

[0206] Example 5: Curing and color measurement of coatings in the presence of anti-yellowing additives The following hybrid formulations (controls) were prepared for cure and color evaluation: TIFF2026500735000092.tif73170Anti-yellowing additives were then added to the control at the levels shown in Table 25. The test formulations were coated onto Leneta 3NT-31 paper substrate (50 μm coating thickness) and passed under a 395 nm LED light source (5 W / cm2, 10 passes). Color measurements of the cured coatings were taken immediately after curing using a PCE colorimeter (model #PCE-CSM3). TIFF2026500735000093.tif139170

[0207] Example 6: Solubility of Phospho Initiators in Propylene Carbonate The solubilities of selected sulfonium salts in propylene carbonate at ambient temperature (20-25°C) were determined. TIFF2026500735000094.tif73170

Claims

1. A cationically polymerizable compound and a compound of formula (I): (In the above formula, Y is an anion with a valence of y, -R １２ and R １３ are bonded to each other to form groups but where: -R １６ , R １７ , R １８ and R １９ are independently H, halogen, (C １ -C ６ ) a linear or branched alkyl group, (C １ -C ６ ) straight-chain or branched alkoxy group, —O—(CH ２ ) ｉ -COOR ２８ Or -(CH ２ ) ｉ -CH-(COOR ２８ ) ２ group (where i is 1 or 2 and R ２８ is H or (C １ -C ４ ) a straight chain or branched alkyl group; and -R １１ , R １４ and R １５ are independently H, halogen, (C １ -C ６ ) a linear or branched alkyl group, (C １ -C ６ ) a linear or branched alkoxy group and —S—Ph—C(═O)—Ph; - Or R １２ and R １３ are not bonded to each other, and R １１ , R １２ and R １３ are independently H, halogen, (C １ -C ６ ) a linear or branched alkyl group, (C １ -C ６ ) a straight-chain or branched alkoxy group, pyrrolidin-1-yl, -L-Ph １ group (wherein L is a single bond, CH ２ or O, Ph １ is a halogen, (C １ -C ６ ) a linear or branched alkyl group and (C １ -C ６ ) a phenyl group optionally substituted with one or more substituents selected from a linear or branched alkoxy group, with the proviso that R １１ , R １２ and R １３ At least one of the following is -L-Ph １ is a group, and R １４ and R １５ are independently H, halogen, (C １ -C ６ ) a linear or branched alkyl group, (C １ -C ６ ) a linear or branched alkoxy group and —S—Ph—C(═O)—Ph; -R ３ is H, halogen, (C １ -C ６ ) a linear or branched alkyl group, (C １ -C ６ ) straight-chain or branched alkoxy group, —O—(CH ２ ) ｌ -COOR ３１ group and -(CH ２ ) ｌ -CH-(COOR ３１ ) ２ group (where l is 1 or 2 and R ３１ is H or (C １ -C ４ ) a linear or branched alkyl group; -R ２ , R ４ , R ５ , R ７ , R ８ , R ９ and R １０ are independently H, halogen, (C １ -C ６ ) a linear or branched alkyl group, (C １ -C ６ ) straight-chain or branched alkoxy groups and —O—(CH ２ ) ｍ -COOR ３２ Or -(CH ２ ) ｍ -CH-(COOR ３２ ) ２ group (where m is 1 or 2, and R ３２ is H or (C １ -C ４ ) a linear or branched alkyl group) and a photoinitiator of formula (I), comprising irradiating the composition with at least one light source having a maximum output wavelength in the range of 350 to 460 nm.

2. In the photoinitiator formula (I), R １２ and R １３ are bonded to each other to form groups but and thus the photoinitiator represents formula (IV): (In the above formula, R ２ , R ３ , R ４ , R ５ , R ７ , R ８ , R ９ , R １０ , R １１ , R １４ , R １５ , R １６ , R １７ , R １８ , R １９ , Y and y are as defined in claim 1) 2. The method of claim 1, comprising:

3. -R ２ , R ４ , R ７ , R ８ , R ９ and R １０ represents H, and R ５ is H, halogen, (C １ -C ６ ) a linear or branched alkyl group; R ３ is halogen, (C １ -C ６ ) a linear or branched alkyl group, (C １ -C ６ ) straight-chain or branched alkoxy group, —O—(CH ２ ) ｌ -COOR ３１ group and -(CH ２ ) ｌ -CH-(COOR ３１ ) ２ group (where l is 1 or 2 and R ３１ is H or (C １ -C ４ ) a linear or branched alkyl group; R ３ is preferably halogen, (C １ -C ６ ) a linear or branched alkyl group and (C １ -C ６ ) a linear or branched alkoxy group; R ３ is most preferably (C １ -C ６ ) a linear or branched alkyl group; or R ３ , R ４ , R ７ , R ８ , R ９ and R １０ is H and R ２ and R ５ are independently halogen, (C １ -C ６ ) a linear or branched alkyl group, (C １ -C ６ ) linear or branched alkoxy groups, and —O—(CH ２ ) ｍ -COOR ３２ Or -(CH ２ ) ｍ -CH-(COOR ３２ ) ２ group (where m is 1 or 2, and R ３２ is H or (C １ -C ４ ) a linear or branched alkyl group; R ２ and R ５ is preferably a halogen, (C １ -C ６ ) a linear or branched alkyl group, and (C １ -C ６ ) independently selected from linear or branched alkoxy groups, R ２ and R ５ is most preferably a halogen and (C １ -C ６ 3. The method of claim 2, wherein the alkoxy groups are independently selected from the group consisting of: a) linear or branched alkoxy groups;

4. In the photoinitiator formula: -R １６ , R １８ , R １１ , R １４ and R １５ represents H, and R １９ is H, halogen, (C １ -C ６ ) a linear or branched alkyl group; R １７ is halogen, (C １ -C ６ ) a linear or branched alkyl group, (C １ -C ６ ) straight-chain or branched alkoxy group, —O—(CH ２ ) ｉ -COOR ２８ Or -(CH ２ ) ｉ -CH-(COOR ２８ ) ２ group (where i is 1 or 2 and R ２８ is H or (C １ -C ４ ) a linear or branched alkyl group; R １７ is preferably halogen, (C １ -C ６ ) a linear or branched alkyl group and (C １ -C ６ ) a linear or branched alkoxy group; R １７ is most preferably (C １ -C ６ ) a linear or branched alkyl group; or -R １７ , R １８ , R １１ , R １４ and R １５ is H and R １６ and R １９ is a halogen, (C １ -C ６ ) a linear or branched alkyl group, (C １ -C ６ ) linear or branched alkoxy groups, and —O—(CH ２ ) ｉ -COOR ２８ Or -(CH ２ ) ｉ -CH-(COOR ２８ ) ２ group (where i is 1 or 2 and R ２８ is H or (C １ -C ４ ) a straight chain or branched alkyl group; １６ and R １９ is preferably a halogen, (C １ -C ６ ) a linear or branched alkyl group, and (C １ -C ６ ) independently selected from linear or branched alkoxy groups, R １６ and R １９ is most preferably a halogen and (C １ -C ６ 4. The method of claim 2 or 3, wherein the alkoxy groups are independently selected from the group consisting of: a) linear or branched alkoxy group;

5. In formula (IV), R ７ and R １１ are identical, R ９ and R １５ are identical, R １０ and R １４ are identical, R ２ and R １６ are identical, R ３ and R １７ are identical, R ４ and R １８ are identical, and R ５ and R １９ are identical, The photoinitiator is represented by formula (V): (In the above formula, -R ７ , R ９ and R １０ are independently H, halogen, (C １ -C ６ ) a linear or branched alkyl group, or (C １ -C ６ ) a linear or branched alkoxy group; -R ２ , R ３ , R ４ and R ５ are independently H, halogen, (C １ -C ６ ) a linear or branched alkyl group, (C １ -C ６ ) straight-chain or branched alkoxy group, —O—(CH ２ ) ｍ -COOR ３２ Or -(CH ２ ) ｍ -CH-(COOR ３２ ) ２ group, where m is 1 or 2, and R ３２ is H or (C １ -C ４ ) a straight chain or branched alkyl group; and -R ８ , Y and y are as defined in claim 1) 5. The method according to claim 2, wherein the method comprises:

6. The photoinitiator is represented by formula (1), (5), (6), (40), (44), (45), (46), (47), (48) or (49), preferably formula (1) or (5): (wherein Y and y are as defined in claim 1) 3. The method of claim 2, comprising:

7. In the photoinitiator formula (I), R １２ and R １３ are not bonded to each other, and the photoinitiator has the formula (VII): (In the above formula, R ２ , R ３ , R ４ , R ５ , R ７ , R ８ , R ９ , R １０ , R １１ , R １２ , R １３ , R １４ , R １５ , Y and y are as defined in claim 1) 2. The method of claim 1, comprising:

8. The photoinitiator is represented by formula (VIII): (In the above formula, -R ２ , R ３ , R ４ , R ５ , R ７ , R ８ , R ９ , R １０ , Y and y are as defined in claim 1; -R ２０ and R ２１ are independently H, halogen, (C １ -C ６ ) a linear or branched alkyl group, (C １ -C ６ ) linear or branched alkoxy groups, preferably H and (C １ -C ６ ) straight chain or branched alkoxy groups, most preferably selected from H and OMe.

8. The method of claim 7, comprising:

9. R ２１ (C １ -C ６ 9. The method of claim 8, wherein alkoxy is a linear or branched alkoxy group, preferably OMe.

10. The photoinitiator is represented by formula (12), (16), (26), (28), (32) or (33), preferably formula (26), (28), (32) or (33): (wherein Y and y are as defined in claim 1) 8. The method of claim 7, comprising:

11. 11. A method according to any one of the preceding claims, wherein the light source has a maximum output wavelength of 380 to 430 nm, even more preferably 385 nm or 395 nm or 405 nm or 420 nm.

12. 12. The method according to any one of claims 1 to 11, wherein the light source is a broadband lamp or a light emitting diode (LED) equipped with an optical filter that limits the emission to wavelengths in the range of 350 to 460 nm.

13. 13. The method of any one of claims 1 to 12, wherein the cationically polymerizable compound comprises at least one compound selected from epoxides, oxetanes, oxolanes, cyclic acetals, cyclic lactones, thiiranes, thietanes, spiroorthoesters, vinyl ethers, and mixtures thereof, preferably cycloaliphatic epoxides, and optionally oxetanes.

14. The composition further comprises a radical polymerizable compound and optionally a radical photoinitiator, wherein: the radically polymerizable compound preferably comprises at least one ethylenically unsaturated compound, most preferably a (meth)acrylate-functionalized compound, and / or The method according to any one of claims 1 to 13, wherein the radical photoinitiator is preferably selected from benzoin, benzoin ethers, acetophenone, α-hydroxyacetophenone, benzil, benzil ketals, phosphine oxides, acylphosphine oxides, α-hydroxyketones, phenylglyoxylates, α-aminoketones, benzoyl formates, acylgermanyl compounds, polymeric derivatives thereof, and mixtures thereof, more preferably acetophenone, α-hydroxyacetophenone, phosphine oxides and acylphosphine oxides, even more preferably acetophenone and acylphosphine oxides.

15. 15. The method of any one of claims 1 to 14, wherein the composition further comprises an anti-yellowing agent, preferably an anti-yellowing agent containing an amino group such as an aminobenzoate group, or a thio group such as an agent containing both a (phenylthio) group and a carboxylic acid group, or a mixture thereof, the anti-yellowing agent most preferably being selected from ethyl-4-(dimethylamino)benzoate, (phenylthio)acetic acid, and mixtures thereof.

16. A cured product obtained according to the method of any one of claims 1 to 15.

17. 16. A method for preparing a 3D printed article, comprising the method of any one of claims 1 to 15.

18. a) depositing a first layer of the composition of any one of claims 1 to 10 and 13 to 15 onto a surface; b) at least partially curing the first layer according to the method of any one of claims 1 to 15 to provide a cured layer; c) depositing a second layer of the composition onto the cured first layer; d) at least partially curing the second layer according to the method of any one of claims 1 to 15 to provide a cured second layer adhered to the cured first layer; e) repeating steps c) and d) a desired number of times to build a 3D printed article; and Optionally, a post-curing step of heating or microwaving the 3D printed article.

18. The method of claim 17, comprising:

19. a) providing a carrier and an optically transparent member having a build surface, the carrier and the build surface defining a build area therebetween; b) filling the construction area with a composition according to any one of claims 1 to 10 and 13 to 15; c) continuously or intermittently hardening a portion of the composition in the build area to form a hardened composition according to the method of any one of claims 1 to 15; d) continuously or intermittently advancing the carrier from the build surface to form a 3D printed article from the hardened composition; and Optionally, a post-curing step of heating or microwaving the 3D printed article.

20. The method of claim 18, comprising:

20. 20. A 3D printed article obtainable by the method of any one of claims 17 to 19.

21. Formula (VIII): (In the above formula, Y is an anion with a valence of y, -R ３ is H, halogen, (C １ -C ６ ) a linear or branched alkyl group, (C １ -C ６ ) straight-chain or branched alkoxy group, —O—(CH ２ ) ｌ -COOR ３１ group, and -(CH ２ ) ｌ -CH-(COOR ３１ ) ２ group (where l is 1 or 2 and R ３１ is H or (C １ -C ４ ) a linear or branched alkyl group; -R ２ , R ４ , R ５ , R ７ , R ８ , R ９ and R １０ are independently H, halogen, (C １ -C ６ ) a linear or branched alkyl group, (C １ -C ６ ) linear or branched alkoxy groups, and —O—(CH ２ ) ｍ -COOR ３２ Or -(CH ２ ) ｍ -CH-(COOR ３２ ) ２ group (where m is 1 or 2, and R ３２ is H or (C １ -C ４ ) a straight chain or branched alkyl group; and -R ２０ and R ２１ are independently H, halogen, (C １ -C ６ ) a linear or branched alkyl group, (C １ -C ６ ) linear or branched alkoxy groups, preferably H and (C １ -C ６ ) straight chain or branched alkoxy groups, most preferably selected from H and OMe. Compound.

22. R ２１ (C １ -C ６ 22. The compound according to claim 21, wherein R is a linear or branched alkoxy group, preferably OMe.

23. Formula (26), (28), (32) or (33): (wherein Y and y are as defined in claim 21) 23. The compound according to claim 21 or 22.

24. Formula (V'): (In the above formula, Y is an anion with a valence of y, -R ３ , R ４ , R ７ , R ９ and R １０ is H, and -R ２ and R ５ are independently halogen, (C １ -C ６ ) a linear or branched alkyl group, (C １ -C ６ ) linear or branched alkoxy groups, and —O—(CH ２ ) ｍ -COOR ３２ Or -(CH ２ ) ｍ -CH-(COOR ３２ ) ２ group (where m is 1 or 2, and R ３２ is H or (C １ -C ４ ) a linear or branched alkyl group; R ２ and R ５ are preferably independently halogen, (C １ -C ６ ) a linear or branched alkyl group, and (C １ -C ６ ) a linear or branched alkoxy group; R ２ and R ５ is most preferably a halogen and (C １ -C ６ ) independently selected from linear or branched alkoxy groups. Compound.

25. Formula (5): (wherein Y and y are as defined in claim 1) The compound of claim 24.

26. q) Formula (XX') (In the above formula, R ２ , R ３ , R ４ , R ５ , R ７ , R ８ , R ９ , R １０ is as defined in claim 24) and a compound of formula (XXI'): (In the above formula, R ２ , R ３ , R ４ , R ５ , R ７ , R ８ , R ９ , R １０ as defined in claim 24), adding acetic anhydride and an acid to the mixture, thereby obtaining a photoinitiator of formula (V'), r) a photoinitiator of formula (V') is desired, Y ｙ－ is different from that obtained in step q), Y' ｙ－ as an anion, or Y' ｙ－ carrying out an ion exchange reaction with an acid having a base Y' to obtain a photoinitiator of formula (V), ｙ－ However, the above-described Y ｙ－ and Y obtained in step q) ｙ－ A different process 25. A process for preparing a compound of formula (V') according to claim 24, comprising:

27. a compound of formula (VIII) according to any one of claims 21 to 23 or a compound of formula (V') according to claim 24 or 25; and - cationically polymerizable compounds, - optionally an anti-yellowing agent A curable composition comprising:

28. 28. The curable composition of claim 27, wherein the compound has formula (26), (28), (32), (33), or (5).

29. 29. The curable composition of claim 27 or 28, comprising an anti-yellowing agent comprising an amino group such as an aminobenzoate group, or a thio group such as an agent comprising both a (phenylthio) group and a carboxylic acid group, or a mixture thereof, wherein the anti-yellowing agent is most preferably selected from ethyl-4-(dimethylamino)benzoate, (phenylthio)acetic acid, and mixtures thereof.

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