Hybrid photocurable composition

Abstract

The chemically active radiation curable composition comprises: a) one or more oxetane functional compounds; b) one or more epoxy functional compounds; c) one or more (meth)acrylate functional compounds; and d) one or more photoinitiators. The oxetane functional compounds are present in the composition at 55% to 90% by weight, preferably 60% to 90% by weight, more preferably 70% to 90% by weight, based on the combined weight of the oxetane functional compounds and the epoxy functional compounds in the composition.

Description

[Technical field]

[0001] The present invention relates to actinically cured materials, including those useful in additive manufacturing applications. [Background technology]

[0002] Light-curable materials are well known and useful for additive manufacturing applications, also referred to as three-dimensional printing (3D printing), including the stereolithography (SL) printing process. In recent years, as LED (light-emitting diode) lights have become cheaper and available in a variety of wavelengths, there has been interest in using them for the light exposure required to cure 3D printed parts.

[0003] Acrylate-based radiation curable systems cure quickly but shrink during curing. Hybrid systems including blends of acrylate-based radiation curable resins with epoxy-based and / or oxetane-based radiation curable resins have been introduced to reduce shrinkage. However, although epoxy and oxetane materials cure much slower than acrylate-based systems, they continue to cure even in the absence of light because they cure cationically. Oxetane-based resins exhibit significantly reduced shrinkage than epoxy-based resins. However, oxetane resins are known to cure slower than epoxy-based resins when used by themselves.

[0004] Traditionally, solid-state lasers with a wavelength of 355 nm and very high intensity, e.g., 25 mW (milliwatts) up to 2000 mW, typically 100 mW to about 1500 mW, have been used to cure these epoxy, oxetane and acrylate hybrid systems. Despite the slower cure rates of cationically cured epoxy and oxetane resins, the shorter wavelength and higher intensity of these lasers have been sufficient to achieve fast cure in these hybrid systems.

[0005] In recent years, LED (light emitting diode) and LCD (liquid crystal) curing systems have become popular due to their improved environmental compatibility and lower cost than older solid-state lasers. However, LED and LCD curing systems provide longer wavelengths, typically 365 nm, 385 nm, 395 nm, 405 nm, 450 nm or 500 nm, and lower intensity than solid-state lasers. Thus, epoxy and oxetane resins in these hybrid systems cure much slower using LED or LCD-based UV curing systems. However, it is desirable to include oxetane-based resins in hybrid systems because they have the advantage of improving green strength and final properties, and even lower shrinkage than epoxy resins in hybrid systems containing acrylates.

[0006] In a typical hybrid resin, the cationic cure portion of the composition (epoxy / oxetane) provides many benefits, but usually cures much slower than the acrylate portion of the composition. Traditionally, a combination of up to 20% by weight of oxetane with epoxide, for example, a mixture of 20% by weight of Uvicure S130 (Sartomer / Lambson) oxetane and 80% by weight of Uvicure S105 (Sartomer / Lambson) epoxy relative to the weight of the cationic cure portion of the composition, is recommended to accelerate the cationic cure rate. This 20% by weight level of oxetane improves green strength to some extent, but the major part of the green strength is due to the approximately 5 to 30% by weight of high functionality acrylate in this hybrid system. Previously, in conventional 3D printers with 355 nm solid-state lasers, the cure rate of this composition was good enough to build up the desired green strength. However, these stereolithography (SL) resins have great difficulty in building parts with sufficient green intensity when used in 3D printers equipped with LEDs with wavelengths of 365 nm, 385 nm, 395 nm, or 405 nm for monochromatic LCD lamps, and the slow curing of the cationic portion of the hybrid system (epoxy and oxetane) has been a bottleneck to commercial success. This is due to the low light intensity provided by LED and LCD 3D printers. Thus, these hybrid systems, including epoxy and oxetane resins, are currently severely limited in their use in conventional hybrid system applications with LED or LCD printers.

[0007] Therefore, there is a need for activating radiation curable blends of acrylate resins, epoxy resins, and oxetane resins that provide improved cure speeds when exposed to longer wavelength and lower intensity light.

[0008] J. Appl. Polym. Sci. 2020, 137, 48333 discloses a cationic / free radical photopolymer consisting of two epoxies and a tetrafunctional acrylate.

[0009] Polym. Int. 2016; 65: 1486-1492 discloses cationic photopolymerization of 3-benzyloxymethyl-3-ethyl-oxetane (MOX104) initiated by triphenylsulfonium hexafluoroantimonate under UV light.

[0010] J. Photopolym. Sct. Technol., pages 119-124, Vol. 13, No. 1, 2000, discloses five oxetane monomers that were evaluated in photocationically cured systems.

[0011] J. Polym. Sci. Part A: Polym. Chem. 43: 3205-3220, 2005 discloses photoinitiated cationic ring-opening polymerization of onium salts of various 3,3-disubstituted oxetane monomers.

[0012] Polymer 42 (2001) 5531-5541 discloses interpenetrating polymer networks (IPNs) synthesized by photoinduced crosslinking polymerization of mixtures of acrylate and epoxide monomers.

[0013] U.S. Pat. No. 7,183,040 discloses a radiation-curable composition that contains, based on the total weight of the composition, (A) 0 to 29% by weight of a cationically curable component having an aliphatic ester linking group, (B) 10 to 85% by weight of an epoxy group-containing component other than A, (C) 1 to 50% by weight of an oxetane group-containing component, and (D) 1 to 25% by weight of a multifunctional acrylate, as well as a radical photoinitiator and a cationic photoinitiator.

[0014] US Patent No. 7,696,260 discloses a composition comprising a cationically polymerizable compound, an iodonium-based cationic initiator, a sensitizer for the cationic initiator, and an antioxidant selected from the group consisting of phenolic antioxidants, lactone antioxidants, and combinations of these antioxidants, the addition of which to the composition contributes to reducing the likelihood of runaway reactions when exposed to actinic radiation in bulk.

[0015] US Patent No. 9,861,452 discloses a liquid radiation-curable resin composition for additive manufacturing, comprising about 5 to about 30% by weight of an oxetane; a (meth)acrylate component; a cationic photoinitiator; a free radical photoinitiator; and about 50 to about 80% by weight of an epoxy, further comprising a cycloaliphatic epoxy component and an epoxy component having an aromatic glycidyl ether group, the majority of the epoxy being the cycloaliphatic epoxy component. Also disclosed is a method of using the liquid radiation-curable resin for additive manufacturing to make a mold for a dental aligner, and a three-dimensional mold made from the liquid radiation-curable resin for additive manufacturing. [Prior art documents] [Patent documents]

[0016] [Patent Document 1] U.S. Patent No. 7,183,040 [Patent Document 2] U.S. Patent No. 7,696,260 [Patent Document 3] U.S. Pat. No. 9,861,452 [Patent Document 4] U.S. Patent Publication No. 2010 / 0222512 A1 [Patent Document 5] U.S. Pat. No. 3,835,003 [Patent Document 6] U.S. Patent No. 5,750,590 [Patent Document 7] U.S. Pat. No. 5,674,922 [Patent Document 8] U.S. Pat. No. 5,981,616 [Patent Document 9] U.S. Patent No. 6,469,108 [Patent Document 10] U.S. Patent No. 6,015,914 [Patent Document 11] U.S. Patent No. 8,377,623 [Non-patent literature]

[0017] [Non-Patent Document 1] J. Appl. Polym. Sci. 2020, 137, 48333 [Non-Patent Document 2] Polym. Int. 2016; 65: 1486-1492 [Non-Patent Document 3] J. Photopolym. Sct. Technol., page 119-124, Vol.13, No.1, 2000 [Non-Patent Document 4] J. Polym. Sci. Part A: Polym. Chem. 43: 3205-3220, 2005 [Non-Patent Document 5] Polymer 42 (2001) 5531-5541 Summary of the Invention [Problem to be solved by the invention]

[0018] Therefore, there is a need for activating radiation curable blends of acrylate, epoxy and oxetane resins that provide improved cure speed when exposed to longer wavelength and lower intensity light. [Means for solving the problem]

[0019] Various oxetane compounds in conventional hybrid SL resins were evaluated. The results showed that up to 20% by weight of oxetane, based on the total weight of the cationically curable compounds in the resin, provided some improvement in the cure speed. Surprisingly, the cure speed increased when the proportion of slow-curing oxetane moieties in the cationically curable compounds was increased. This new discovery not only provides an effective approach to speed up the cationic cure of hybrid systems, but also allows more oxetane to be introduced into the composition to meet or exceed the print performance of conventional hybrid SL systems, such as faster cure speed, stronger green strength with desirable viscosity, improved mechanical properties, and higher thermodynamic properties. For example, up to 80% by weight of Uvicure S130 with 20% by weight of cycloaliphatic epoxide, based on the total weight of the cationically curable compounds, provided the maximum cure speed for the hybrid system. Furthermore, the introduction of higher weight percentages of dioxetane-functional compounds into the hybrid system provided increased cure speed and achieved or exceeded the targeted mechanical properties of the cured parts.

[0020] A chemically active radiation curable composition is provided. The composition comprises, consists of, or consists essentially of the following components: a) one or more oxetane functional compounds; b) one or more epoxy functional compounds; c) one or more acrylate functional compounds; d) at least one photoinitiator; and, optionally, at least one additive. The composition comprises 55% to 90% by weight, preferably 60% to 90% by weight, more preferably 70% to 90% by weight of one or more oxetane functional compounds, based on the total weight of the one or more oxetane functional compounds and the one or more epoxy functional compounds in the composition. For example, the weight ratio of the total amount of oxetane functional compounds to the total amount of epoxy functional compounds may be 90:10 to 55:45, or 90:10 to 60:40, or 85:15 to 75:25.

[0021] Also provided is a method for preparing a 3D printed article, the method comprising at least the following steps: a) providing a first layer of a curable composition of any embodiment described herein on a surface; b) at least partially curing the first layer to provide a cured first layer; c) providing a second layer of a curable composition over the cured first layer; d) at least partially curing the second layer 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. Includes. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] A chemically active radiation curable composition is provided that comprises, consists of, or consists essentially of the following components: a) one or more oxetane-functional compounds, b) one or more epoxy-functional compounds, c) one or more acrylate-functional compounds, d) one or more photoinitiators, and, optionally, at least one additive.

[0023] The chemically active radiation curable composition comprises 55% to 90% by weight, preferably 60% to 90% by weight, more preferably 70% to 90% by weight of one or more oxetane functional compounds, based on the total weight of one or more oxetane functional compounds and one or more epoxy functional compounds in the composition. When the composition comprises a mixture of multiple oxetane functional compounds and / or a mixture of multiple epoxy functional compounds, the above weight percentages can be calculated using the total weight of the mixture of multiple oxetane functional compounds and / or the total weight of the mixture of multiple epoxy functional compounds.

[0024] As shown in the examples, the inventors have discovered that, contrary to the expected results of a slow curing composition, increasing the proportion of the oxetane component (which is the slowest curing component in the composition) exhibits improved cure rates, peaking at about 80 wt. % oxetane, relative to the combined weight of the oxetane and epoxy components in the composition.

[0025] a) Oxetane-functional compounds The oxetane functional compound may be a monomer and / or an oligomer. The total amount of the oxetane functional compound may be from 55% to 90% by weight, preferably from 60% to 90% by weight, more preferably from 70% to 90% by weight, based on the total weight of the oxetane functional compound and the epoxy functional compound in the composition.

[0026] For example, the chemically active radiation curable composition may comprise at least 55% by weight, at least 56%, at least 57%, at least 58%, at least 59%, at least 60%, at least 61%, at least 62%, at least 63%, at least 64%, at least 65%, at least 66%, at least 67%, at least 68%, at least 69%, at least 70%, at least 71%, at least 72%, at least 73%, at least 74%, at least 75%, at least 76%, at least 77%, at least 78%, at least 79%, or at least 80% oxetane functional compounds based on the combined weight of oxetane functional compounds and epoxy functional compounds in the composition. According to other embodiments, the actinic radiation curable composition may include up to 90% by weight, up to 89% by weight, up to 88% by weight, up to 87% by weight, up to 86% by weight, up to 85% by weight, up to 84% by weight, up to 83% by weight, up to 82% by weight, up to 81% by weight, or up to 80% by weight of the oxetane functional compound, based on the combined weight of the oxetane functional compound and the epoxy functional compound in the composition. For all ranges or limits set forth herein for a particular parameter (including the weight percentage of a given component), the invention includes all ranges extending from any lower limit to any upper limit set forth herein.

[0027] The chemically active radiation curable composition may comprise 10% to 90% by weight, preferably 30% to 85% by weight, more preferably 50% to 80% by weight, and most preferably 55% to 80% by weight of one or more oxetane functional compounds, based on the total weight of the curable composition. When the composition comprises a mixture of oxetane functional compounds, the above weight percentages can be calculated using the weight of the mixture of oxetane functional compounds.

[0028] Examples of suitable oxetanes include oxetane itself and its substituted derivatives, provided that the substituents do not interfere with the desired reaction / polymerization / curing of the oxetane. The substituents may be, for example, alkyl, hydroxyalkyl, halo, haloalkyl, aryl, and aralkyl groups. The oxetane may be a monooxetane (a compound having a single oxetane ring), a dioxetane (a compound having two oxetane rings), a trioxetane (a compound having three oxetane rings), or an oxetane compound having four or more oxetane rings. Examples of suitable oxetanes include, but are not limited to, oxetane, trimethylolpropane oxetane, 3-ethyl-3-hydroxymethyl oxetane, 1,4-bis[(3-ethyl-3-oxetanylmethoxy)methyl]benzene, 3-ethyl-3-phenoxymethyl oxetane, bis[(1-ethyl(3-oxetanyl))methyl]ether, 3,3-bis(chloromethyl oxetane), 3-ethyl-3-[(phenylmethoxy)methyl]-oxetane, bis[1-ethyl(3-oxetanyl)]methyl ether, 1,4-bis[(3-ethyl-3-oxetanylmethoxy)methyl]benzene, 4,4-bis(3-ethyl-3-oxetanyl)methoxymethyl]biphenyl. phenyl, 3,3-bis(iodomethyl)oxetane, 3,3-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, 3,3'-[1,4-phenylenebis(methyleneoxymethylene)]bis[3-ethyloxetane], 3-ethyl-3-[[(2-ethylhexyl)oxy]methyl]oxetane, and trimethylolpropane tris(3-ethyl-3-oxetanylmethyl)ether, and the like, and combinations thereof.

[0029] Examples of compounds having two or more oxetane rings that can be used in the present invention 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-oxetanylmethoxy)methyl]propane, and the like. 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 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, and EO-modified bisphenol F(3-ethyl-3-oxetanylmethyl)ether, and combinations thereof.

[0030] Additional examples of suitable oxetanes are described in the following patent documents: U.S. Patent Publication No. 2010 / 0222512 A1, 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, the disclosures of each of which are incorporated herein by reference in their entirety for all purposes. Suitable oxetanes are available from commercial sources, such as oxetanes sold by Toagosei Corporation under the trade names OXT-221, OXT-121, OXT-101, OXT-212, OXT-211, CHOX, OX-SC, and PNOX-1009.

[0031] Also suitable are oxetanes further comprising one or more ethylenically unsaturated polymerization sites, which may be provided by, for example, (meth)acrylate, (meth)acrylamide, vinyl or allyl groups. 3-Ethyl-3-(methacryloyloxy)methyloxetane or (3-ethyloxetan-3-yl)methyl(meth)acrylate are specific examples of such compounds. These compounds are included in the calculation of the amount of oxetane in the curable composition.

[0032] The curable compositions may also contain compounds having two or more different types of polymerizable heterocycles. For example, the compounds may contain one or more oxetane rings and one or more epoxy rings (3-[(oxiranylmethoxy)methyl]oxetane is an example of such a compound). These compounds are included as both epoxy-bearing and oxetane-containing compounds in calculating the relative amount of oxetane based on the total amount of oxetane-functional and epoxy-functional compounds in the composition.

[0033] b) Epoxy-functional compounds The epoxy functional compound may be a monomer and / or an oligomer. The curable composition may contain 5% to 40% by weight, preferably 10% to 30% by weight, more preferably 10% to 20% by weight of one or more epoxy functional compounds, based on the total weight of the curable composition. When the composition contains a mixture of epoxy functional compounds, the above weight percentages can be calculated using the weight of the mixture of epoxy functional compounds.

[0034] Exemplary epoxy-functional compounds suitable for use in the present invention include monoepoxides, diepoxides, and polyepoxides (compounds with three or more epoxy groups per molecule).Cycloaliphatic polyglycidyl compounds and cycloaliphatic polyepoxides are two classes of suitable epoxy-functional compounds.Such compounds have two or more epoxide groups per molecule, and may have a cycloaliphatic ring structure with epoxide groups as side groups (pendant to the cycloaliphatic ring), or may have a structure in which the epoxide group is part of the cycloaliphatic ring structure.

[0035] The epoxy functional compound may comprise, consist of, or consist essentially of at least one epoxy ether. As used herein, the term "epoxy ether" refers to a compound that comprises at least two epoxy groups and at least one ether bond (wherein the ether bond is different from the cyclic ether bond in the epoxy group). In particular, the epoxy ether may comprise at least two epoxy groups and at least two ether bonds (wherein the ether bond is different from the cyclic ether bond in the epoxy group).

[0036] 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 that contains at least two glycidyl ether groups. As used herein, the term "glycidyl ether group" refers to a compound that has the following formula (I): [ka] means the group

[0037] In one embodiment, the at least one epoxy compound may comprise, consist or consist essentially of at least one compound having two glycidyl ether groups, which compound is referred to as a diglycidyl ether. In another embodiment, the at least one epoxy a) may comprise, consist or consist essentially of at least one compound having three glycidyl ether groups.

[0038] The at least one epoxy a) may comprise, consist or consist essentially of at least one compound selected from aromatic epoxies, aliphatic epoxies, and mixtures thereof.

[0039] Epoxy a) may comprise, consist or consist essentially of at least one aromatic epoxy. As used herein, the term "aromatic epoxy" means a compound comprising at least two epoxy groups linked together by an aromatic linker.

[0040] As used herein, the term "aromatic linker" refers to a linker that contains at least one aromatic ring, preferably at least two aromatic rings, more preferably two or three aromatic rings. Aromatic aliphatic linkers, i.e., linkers that contain both aromatic and non-aromatic moieties, are encompassed by the term "aromatic linker."

[0041] The aromatic epoxy may be an aromatic glycidyl ether. As used herein, the term "aromatic glycidyl ether" refers to a compound comprising at least two glycidyl ether groups linked together by an aromatic linker. Such compounds are represented by the following formula (II): [ka] wherein Ar is an aromatic linker; a is at least 2, preferably 2 to 10, more preferably 2 to 6. It can be expressed as:

[0042] The aromatic glycidyl ether may be a bisphenol-based glycidyl ether. As used herein, the term "bisphenol-based glycidyl ether" refers to a compound having at least two glycidyl ether groups linked together by an aromatic linker containing a moiety derived from a bisphenol. Such a compound may be represented by the above formula (II) (wherein a is 2 and Ar is represented by the following formula (III): [ka] wherein L is a linker; R 1 and R 2 is independently selected from alkyl, cycloalkyl, aryl, and halogen atoms; b and c are independently 0 to 4. It can be expressed as:

[0043] In particular, L is -CR 3 R 4 -, -C(=O)-, -SO-, -SO 2 -, -C(=CCl 2 )- and -CR 5 R 6 -Ph-CR 7 R 8 -bond; Here, R3 and R 4 is independently selected from H, alkyl, cycloalkyl, aryl, haloalkyl, and perfluoroalkyl, or R 3 and R 4 may form a ring together with the carbon atoms to which they are attached; R 5 , R 6 , R 7 , and R 8 is independently selected from H, alkyl, cycloalkyl, aryl, haloalkyl, and perfluoroalkyl; Ph is phenylene optionally substituted with one or more groups selected from alkyl, cycloalkyl, aryl, and halogen atoms.

[0044] More specifically, Ar may be a residue of a bisphenol without an OH group. The compound according to formula (III), where Ar is a residue of a bisphenol without an OH group, may also be referred to as 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.

[0045] The epoxy-functional compound may comprise, consist of, or consist essentially of at least one aliphatic epoxy. As used herein, the term "aliphatic epoxy" refers to a compound having at least two epoxy groups linked together by an aliphatic linker.

[0046] As used herein, the term "aliphatic linker" refers to a linker that does not contain any aromatic ring. It may be a linear or branched, cyclic or acyclic, saturated or unsaturated hydrocarbon linker. It may be 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.

[0047] The at least one aliphatic epoxy may be selected from aliphatic glycidyl ethers, epoxidized vegetable oils, and combinations thereof.

[0048] The aliphatic epoxy may be an aliphatic glycidyl ether. As used herein, the term "aliphatic glycidyl ether" refers to a compound that includes at least two glycidyl ether groups linked together by an aliphatic linker. Such compounds may be represented by the following formula (IV): [ka] where Al is an aliphatic linker; d is at least 2, preferably 2 to 10, more preferably 2 to 6. It can be expressed as:

[0049] In particular, Al may be an alkylene, optionally interrupted by one or more ether or ester bonds, or Al may correspond to a partially hydrogenated or fully hydrogenated derivative of the linker of formula (III).

[0050] More specifically, Al is a polyol P having no OH groups. OH Suitable polyols P OHExamples of the ethylene glycol 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, Coal, 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 tetraethylolpropane. These include, for example, diglycerol, 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, glucitol, fucitol, iditol), dianhydrohexitols (i.e. isosorbide, isomannide, isoidide), hydroxylated vegetable oils, tris(2-hydroxyethyl)isocyanurate, polybutadiene polyols, polyester polyols, polyether polyols, polyorganosiloxane polyols, polycarbonate polyols, as well as their alkoxylated (e.g. ethoxylated and / or propoxylated) derivatives and those obtained by ring-opening polymerization of ε-caprolactone initiated with one of the aforementioned polyols.

[0051] The aliphatic epoxy compound may be an epoxidized vegetable oil.

[0052] The term "epoxidized vegetable oil" as used herein means 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 usually comprises one or more unsaturated diglycerides and / or triglycerides. The unsaturated diglycerides and triglycerides may correspond to di- and triesters of glycerol with 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 from 4 to 32 carbon atoms, in particular from 8 to 30 carbon atoms, more particularly from 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 are myristoleic acid, palmitoleic acid, sapienic acid, oleic acid, ricinoleic acid, elaidic acid, basenic acid, linoleic acid, linoelaidic acid, alpha-linolenic acid, arachidonic acid, eicosapentaenoic acid, erucic acid, docosahexaenoic acid, and combinations thereof. Unsaturated vegetable oils can be extracted from plants or trees, such as seeds, fruits, flowers, bark, timber, trunks 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 jetropha oil, epoxidized rubber seed oil, epoxidized tung oil, epoxidized tall oil, and combinations thereof.

[0053] Also suitable are, for example, linear or branched epoxidized polyenes such as epoxidized polybutadienes and copolymers thereof, polyisoprenes, and copolymers thereof.

[0054] 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- 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.

[0055] Examples of suitable monoepoxides include glycidyl (meth)acrylate and (3,4-epoxycyclohexyl)methyl (meth)acrylate, as well as other monoepoxide compounds having epoxy and (meth)acrylate groups.

[0056] Examples of suitable diepoxides include diglycidyl ethers of dialcohols and diglycidyl esters of diacids, such as: ethylene glycol diglycidyl ether, oligo- and polyethylene glycol diglycidyl ether, 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) hexanediol diglycidyl. ethers, cyclohexanedimethanol diglycidyl ether, 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) diglycidyl ethers of bisphenols (e.g., 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.

[0057] Examples of suitable polyepoxides 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 their alkoxylated (e.g., ethoxylated, propoxylated) derivatives, and epoxy novolac resins.

[0058] The curable composition may, in certain embodiments, comprise one or more polymerizable heterocyclic moiety-containing compounds that contain one or more ethylenically unsaturated polymerization sites (in addition to one or more epoxy groups), such as those that may be provided by (meth)acrylate, (meth)acrylamide, vinyl, or allyl groups. Glycidyl methacrylate and glycidyl acrylate are 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 to be epoxies. Suitable examples of epoxy (meth)acrylates include the reaction products of acrylic or methacrylic acid or mixtures thereof with glycidyl ethers or esters.

[0059] Other cationic curing compounds In addition to the oxetane-functional compounds and epoxy-functional compounds in the hybrid composition, other cationically curable compounds may be included in the hybrid composition. Non-limiting examples of such compounds include compounds with free hydroxyl groups. The total mass of the cationically curable compounds, including epoxides, oxetanes, and free hydroxyl components (e.g., hydroxyl groups from SpeedCure S130, alcohols, OH from polyols, and OH from (meth)acrylates), should constitute 100% of the mass of the cationic system of the composition.

[0060] Even if other cationically curable compounds are present in the curable composition, the weight percentages of the one or more oxetane functional compounds referred to herein (i.e., 55% to 90%, or 60% to 90%, or 70% to 90% by weight of the one or more oxetane functional compounds) are based on the combined amount of the one or more oxetane functional compounds and the one or more epoxy functional compounds in the composition, and not on the total weight of all cationically curable compounds.

[0061] Thus, polyols are optionally included in the curable composition. As used herein, the term "polymeric polyol" refers to a polymer having two or more isocyanate-reactive hydroxyl groups per molecule. As used herein, the term "non-polymeric 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 repeat units per molecule, and the term "non-polymeric compound" refers to a compound having up to four repeat units per molecule (thus both monomeric compounds and oligomeric compounds containing two to four repeat 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 repeat units is an example of a polymeric polyol.

[0062] Preferably, the hydroxyl groups are primary and / or secondary hydroxyl groups. When the polyol is a polymeric polyol, the hydroxyl groups may be located at the ends of the polymer according to certain embodiments. However, it is also possible that the hydroxyl groups are located along the main chain of the polymer, or on side chains or groups pendant to the main chain of the polymer. The polymeric portion of the polymeric polyol may be composed of multiple types of repeating units, such as oxyalkylene units, ester units, carbonate units, acrylic units or alkylene units, or combinations thereof.

[0063] According to one particular embodiment of the present invention, the polymeric polyol has the following structure: H.O.R. 9 -OH (In the formula, R 9 is a chain or linker of a polyether (e.g., polyoxyalkylene), polycarbonate, polydiene, polyorganosiloxane, or polyester) It can be expressed as:

[0064] Particularly preferred polymeric polyols include polyether diols and polyester diols. Suitable polyether diols include, for example, polytetramethylene glycol (hydroxyl functionalized polymer of tetrahydrofuran) and polyethylene glycol (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).

[0065] Other types of polymeric polyols that may be 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 hydrogenated or partially hydrogenated polydiene polyols).

[0066] The molecular weight of the polymeric polyol can be varied as may be required or desired to achieve certain properties in the cured composition obtained by curing the curable composition. For example, the number average molecular weight of the polymeric polyol may be at least 300, at least 350, or at least 400 g / mol. In other embodiments, the number average molecular weight of the polymeric polyol may be 5000 g / mol or less, 4500 g / mol or less, or 4000 g / mol or less. For example, the number average molecular weight of the polymeric polyol may be 250 to 5000 g / mol, 300 to 4500 g / mol, or 350 to 4000 g / mol.

[0067] According to one particular embodiment of the invention, the polyol has the following structure: H.O.R. 9 -OH (In the formula, R 9is a divalent nonpolymeric aliphatic moiety that may optionally contain one or more additional heteroatoms (e.g., O, N, S, and / or halogens). It can be expressed as:

[0068] In certain embodiments of the invention, the diol is or comprises a hydrogenated dimer fatty acid (sometimes also referred to as "dimer diol"), e.g. a non-polymeric polyol, which is a diol obtained by dimerization of 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.

[0069] Other types of suitable non-polymeric polyols include, but are not limited to, C2-C12 aliphatic polyols, diols, and oligomers thereof (having up to four oxyalkylene repeat units). The aliphatic polyols or diols may be linear, branched, or cyclic in structure, with the hydroxyl groups both primary or both secondary, or one or more of each type (e.g., one primary hydroxyl group and one secondary hydroxyl group).

[0070] 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 having up to four oxyalkylene repeat units.

[0071] The optional at least one polyol, when present, may be selected from ethylene glycol, propylene glycol, 1,3-propanediol, 1,2-, 1,3- or 1,4-butanediol, 2-methyl-1,3-propanediol (MP diol), neopentyl glycol, alkoxylated derivatives thereof, polyether diols, polyester diols, polycarbonate diols, and combinations thereof.

[0072] The aliphatic diol (with linear, branched, or cyclic structure) may 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, and 2,4-diethyl-1,5-pentanediol, etc., as well as their short chain oligomers (having up to four oxyalkylene repeat units). Typically, the hydroxyl groups of such aliphatic diols are primary or secondary hydroxyl groups that react readily with the diisocyanates used to make the inherently reactive urethane acrylate oligomers.

[0073] The polyol may be selected from ethylene glycol, propylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol or 1,4-butanediol, 2-methyl-1,3-propanediol (MP diol), neopentyl glycol, alkoxylated derivatives thereof, polyether diols, polyester diols, or polysiloxane diols, and combinations thereof.

[0074] The cationically curable compound may 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.

[0075] c) (Meth)acrylate-functional compounds The curable composition may comprise 5% to 95%, preferably 8% to 90%, more preferably 10% to 80% by weight of one or more (meth)acrylate functional compounds based on the total weight of the curable composition. When the composition comprises a mixture of (meth)acrylate functional compounds, the above weight percentages can be calculated using the weight of the mixture of (meth)acrylate functional compounds.

[0076] The curable composition may contain 40% to 90%, 45% to 85%, 50% to 80%, or 50% to 75% by weight of the (meth)acrylate functional compound based on the total weight of the curable composition. Alternatively, the curable composition may contain 5% to 50%, 8% to 45%, 10% to 40%, or 10% to 30% by weight of the (meth)acrylate functional compound based on the total weight of the curable composition. For example, the curable composition may contain at least 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, or 90% by weight of (meth)acrylate functional compounds, based on the total weight of the curable composition. The curable composition may contain up to 95%, 90%, 85%, 80%, 75%, 70%, 65%, 60%, 55%, 50%, 45%, 40%, 35%, 30%, 25%, or 20% by weight of (meth)acrylate functional compounds, based on the total weight of the curable composition. In one embodiment of the present invention, the composition comprises from 15% to 95% by weight, preferably from 20% to 90% by weight, more preferably from 20% to 60% by weight of one or more (meth)acrylate functional compounds, relative to the total weight of the composition.

[0077] Polymerizable ethylenically unsaturated compounds suitable for use in the present invention other than epoxy and oxetane containing compounds include compounds having at least one carbon-carbon double bond, particularly a carbon-carbon double bond capable of participating in a free radical reaction, where at least one carbon of the carbon-carbon double bond becomes covalently bonded to an atom, particularly a carbon atom, of a second molecule. Such a reaction can lead to polymerization or curing, whereby 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 may have one, two, three, four, five or more carbon-carbon double bonds per molecule. Combinations of ethylenically unsaturated compounds having different numbers of carbon-carbon double bonds can be utilized in the curable compositions of the present invention. The carbon-carbon double bond may 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 is the vinyl group -CH=CH 2 (e.g., allyl group, -CH 2 -CH=CH 2 In the additional ethylenically unsaturated compound, two or more different types of functional groups having a carbon-carbon double bond may be present. For example, the ethylenically unsaturated compound may have 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.

[0078] Polymerizable ethylenically unsaturated compounds that are suitable compounds for use in the present invention include the following classes of compounds (where "functional" 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 analogs; 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 caprolactone-based mono(meth)acrylates prepared by the addition of one, two, three or more moles of caprolactone to a hydroxyalkyl (meth)acrylate, such as 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 analogs; 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 analogs.

[0079] Specific examples of suitable polymerizable ethylenically unsaturated compounds having (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 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, alkoxylated 1,6-hexanediol di(meth)acrylate, alkoxylated aliphatic di(meth)acrylate, 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, penta(meth)acrylate 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, cycloaliphatic acrylate compound, 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. ,

[0080] Suitable polyether (meth)acrylates include, but are not limited to, the condensation reaction products of acrylic acid or methacrylic acid or mixtures thereof with polyetherols, which are polyether polyols. Suitable polyetherols may be linear or branched materials with ether linkages and terminal hydroxyl groups. Polyetherols may be prepared by 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.

[0081] One or more urethane diacrylates can be used in certain embodiments of the present invention. For example, the curable composition may 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 under the trade name CN9782 from Sartomer USA, LLC, Exton, Pennsylvania, can be used as one or more urethane diacrylates. In other embodiments, difunctional aliphatic urethane acrylate oligomers, such as those available under the trade name CN9023 from Sartomer USA, LLC, can be used as 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 compositions of the present invention.

[0082] Suitable acrylic (meth)acrylate oligomers (sometimes referred to in the art as "acrylic oligomers") include oligomers that may be described as materials having an oligomeric acrylic backbone functionalized with one or more (meth)acrylate groups, which may be at the end of the oligomer or pendant to the acrylic backbone. The acrylic backbone may be a homopolymer, random copolymer, or block copolymer made up of repeating units of an acrylic compound. The acrylic compound may be any (meth)acrylate, such as C1-C6 alkyl (meth)acrylates, as well as functionalized (meth)acrylates, such as (meth)acrylates with hydroxyl, carboxylic acid, and / or epoxy groups. The acrylic (meth)acrylate oligomers can be prepared by any procedure known in the art, such as by oligomerizing a compound functionalized at least in some locations 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 designations CN820, CN821, CN822 and CN823.

[0083] 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.

[0084] According to certain embodiments, the curable composition is composed of one or more polymerizable ethylenically unsaturated compounds having one or more hydroxyl groups per molecule. Examples of such ethylenically unsaturated compounds having hydroxyl groups include, but are not limited to, hydroxyalkyl (meth)acrylates (having the general formula H 2 C=C(R)-C(=O)-OR 1 -(OC(=O)-[(CH 2 ) 5 ] n OH, (where R=H, CH 3 , R 1 =C 2 ~C 4 Alkylenes such as ethylene, propylene, butylene, and compounds corresponding to n=1 to 10, e.g., acryloxyethyl di(caprolactone), hydroxyalkyl (meth)acrylates, and caprolactone adducts such as alkoxylated (e.g., ethoxylated and / or propoxylated) hydroxyalkyl (meth)acrylates, including mono(meth)acrylates of ethylene glycol and propylene glycol oligomers and polymers.

[0085] The amount of polymerizable ethylenically unsaturated compounds, particularly acrylate compounds, that may be present in the curable compositions of the present invention is not believed to be particularly critical and can be readily varied as may be desired depending on parameters such as the identity of the polymerizable ethylenically unsaturated compound, the nature of the other components of the curable composition, and the desired properties or attributes of the curable composition and cured compositions obtained therefrom, etc. For example, but not limited to, the curable composition may be comprised of from 5% to 90% by weight in total of polymerizable ethylenically unsaturated compounds.

[0086] d) Photoinitiator In certain embodiments of the present invention, the curable compositions described herein contain one or more photoinitiators and are cured by radiation energy. Photoinitiators are compounds that undergo a chemical change under the action of light (or the synergistic effect of the action of light and the electronic excitation of a sensitizing dye) to generate at least one of radicals, acids, and bases, which then effect a polymerization reaction in one or more polymerizable substances present in the corresponding composition. Photoinitiators capable of effecting polymerization of a free-radical curable component (when subjected to light having an appropriate wavelength and / or intensity) are free-radical photoinitiators. Photoinitiators capable of effecting polymerization of a cationically curable component (when subjected to light having an appropriate wavelength and / or intensity) are cationic photoinitiators. Although certain photoinitiators may act as both free-radical and cationic photoinitiators, typically at least two different photoinitiators are used for this purpose.

[0087] In an embodiment, the composition of the present invention may include a free radical photoinitiator. Typically, free radical photoinitiators include those that form radicals by either Norrish type I or P-type mechanisms. Such photoinitiators include those that form radicals by cleavage, known as "Norrish type I", and those that form radicals by hydrogen abstraction, known as "Norrish type II". Norrish type II photoinitiators require a hydrogen donor entity to act as a free radical source. Because the initiation reaction is based on a bimolecular reaction, Norrish type II photoinitiators are usually slower than Norrish type I photoinitiators, which are based on the unimolecular formation of radicals. On the other hand, Norrish type II photoinitiators have better absorption properties in the near UV spectral region. Photolysis of aromatic ketones, such as benzophenone, thioxanthone, benzil, and quinone, in the presence of hydrogen donor entities, such as alcohols, amines, or thiols, leads to the formation of a radical generated from a carbonyl compound (ketyl-based radical) and another radical derived from the hydrogen donor entity. Photopolymerization of vinyl compounds is usually initiated by radicals generated from hydrogen donor entities. Ketyl radicals are usually not reactive towards vinyl compounds due to steric hindrance and delocalization of the unpaired electron.

[0088] For example, the photoinitiator(s) may include at least one of α-hydroxyketones, phenyl glyoxylates, benzyl dimethyl ketals, α-aminoketones, mono-acylphosphines, bis-acylphosphines, phosphine oxides, and combinations thereof (e.g., blends of alpha hydroxyl ketones or acylphosphine oxides). In certain embodiments, the photoinitiator(s) may be 1-hydroxy-cyclohexyl-phenyl-ketone and / or 2-hydroxy-2-methyl-1-phenyl-1-propanone. In other embodiments, the photoinitiator(s) is or includes a phosphine oxide, in particular bis(2,4-6-trimethylbenzoyl)phenylphosphine oxide, (2,4,6-trimethylbenzoyl)phenylethoxyphosphine oxide, tris(2,4,6-trimethylbenzoyl)phosphine oxide, and liquid mixtures thereof.

[0089] Suitable photoinitiators include, but are not limited to, 2-methylanthraquinone, 2-ethylanthraquinone, 2-chloroanthraquinone, 2-benzanthraquinone, 2-t-butylanthraquinone, 1,2-benzo-9,10-anthraquinone, benzil, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, alpha-methylbenzoin, alpha-phenylbenzoin, Michler's ketone, benzophenone, 4,4'-bis-(diethylamino)benzophenone, acetophenone, 2,2-diethyl Oxyacetophenone, diethyloxyacetophenone, 2-isopropylthioxanthone, thioxanthone, diethylthioxanthone, 1,5-acetonaphthylene, ethyl-p-dimethylaminobenzoate, benzyl ketone, α-hydroxyketone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, benzyl dimethyl ketal, benzyl ketal (2,2-dimethoxy-1,2-diphenylethanone), 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropanol Panone-1,2-hydroxy-2-methyl-1-phenyl-propanone, oligomeric α-hydroxyketones, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, ethyl-4-dimethylaminobenzoate, ethyl(2,4,6-trimethylbenzoyl)phenylphosphinate, anisoin, anthraquinone, anthraquinone-2-sulfonic acid sodium salt monohydrate, (benzene)tricarbonylchromium, benzil, benzoin isobutyl ether, benzophenone / 1-hydroxycyclohexyl phenyl ketone, 50 / 5 0 Blend, 3,3',4,4'-Benzophenonetetracarboxylic dianhydride, 4-Benzoylbiphenyl, 2-Benzyl-2-(dimethylamino)-4'-morpholinobutyrophenone, 4,4'-Bis(diethylamino)benzophenone, 4,4'-Bis(dimethylamino)benzophenone, Camphorquinone, 2-Chlorothioxanthen-9-one, Dibenzosuberenone, 4,4'-Dihydroxybenzophenone, 2,2-Dimethoxy-2-phenylacetophenone, 4-(Dimethylamino)benzophenone, 4,4'-Dimethylbenzyl, 2,5-Dimethylbenzophenone, 3,4-Dimethylbenzophenone, Diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide / 2-hydroxy-2-methylpropiophenone, 50 / 50 blend, 4'-Ethoxyacetophenone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, Phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, Ferrocene, 3'-Hydroxyacetophenone, 4'-Hydroxyacetophenone, 3-Hydroxybenzophenone, 4-Hydroxybenzophenone, 1-Hydroxy Cyclohexyl phenyl ketone, 2-hydroxy-2-methylpropiophenone, 2-methylbenzophenone, 3-methylbenzophenone, methylbenzoyl formate, 2-methyl-4'-(methylthio)-2-morpholinopropiophenone, phenanthrenequinone, 4'-phenoxyacetophenone, (cumene)cyclopentadienyliron(ii) hexafluorophosphate, 9,10-diethoxy and 9,10-dibutoxyanthracene, 2-ethyl-9,10-dimethoxyanthracene, thioxanthen-9-one, and combinations thereof.

[0090] The photocurable composition of the present invention may include at least one cationic photoinitiator, preferably in an amount of about 0.2 to 10% by weight based on the total weight of the photocurable composition. The cationic photoinitiator may be selected from those commonly used to initiate cationic photopolymerization. Examples include onium salts with weakly nucleophilic anions, such as halonium salts, iodosyl salts, sulfonium salts, sulfoxonium salts, or diazonium salts. Metallocene salts are also suitable as photoinitiators. Onium salt and metallocene salt photoinitiators are also suitable as aromatic diazonium salts, aromatic sulfonium salts, aromatic iodonium salts, metallocene-based compounds, aromatic phosphonium salts, acylsulfonium salts, and any combination thereof. In another embodiment, the cation is a polymeric sulfonium salt. In another embodiment, the cationic photoinitiator may be at least one of triarylsulfonium salts, diaryliodonium salts, and metallocene-based compounds, and any combination thereof. Onium salts, such as iodonium and sulfonium salts, and ferrocenium salts, have the advantage that they are generally more thermally stable. In certain embodiments, the cationic photoinitiator is BF 4 - , AsF 6 - , SbF 6 - , P.F. 6 - [B(CF 3 ) 4 ] - , C 6 F 5 ) 4 , B[C 6 H 3 -3,5(CF 3 ) 2 ] 4- , B(C 6 H 4 CF 3 ) 4- , B(C 6 H 3 F 2 ) 4- , B[C 6 F4-4(CF 3 )] 4- , Ga(C6 F 5 ) 4- , [(C 6 F 5 ) 3 B.C. 3 H 3 N 2 -B(C 6 F 5 ) 3 ] - ,(C 6 F 5 ) 3 B-NH 2 -B(C 6 F 5 ) 3 ], tetrakis(3,5-difluoro-4-alkyloxyphenyl)borate, tetrakis(2,3,5,6-tetrafluoro-4-alkyloxyphenyl)borate, perfluoroalkylsulfonates, tris[(perfluoroalkyl)sulfonyl]methides, bis[(perfluoroalkyl)sulfonyl]imides, perfluoroalkylphosphates, tris(perfluoroalkyl)trifluorophosphates, bis(perfluoroalkyl)tetrafluorophosphates, tris(pentafluoroethyl)trifluorophosphate, and (CH 6 B 11 Br 6 ) - , (CH 6 B 11 Br 6 ) - or other halogenated carborane anions.

[0091] Examples of commercially available cationic photoinitiators include Cyracure® UVI-6974 and UVI-6976 (a mixture of S,S,S,S'-tetraphenylthiobis(4,1-phenylene)disulfonium dihexafluoroantimonate and diphenyl(4-phenylthiophenyl)sulfonium hexafluoroantimonate), Cyracure® UVI-6970, UVI-6960, UVI-6990 (DOW Corp.), CD1010, CD-1011, CD-1012 (Sartomer Corp.), Adekaoptomer SP150, SP-151, SP-170, SP-171 (Asahi Denka Kogyo), and others. Co., Ltd.), Irgacure® 261, CI-2481, CI-2624, CI-2639, CI2064 (Nippon Soda Co., Ltd.), and DTS-102, DTS-103, NAT-103, NDS-103, TPS-103, MDS-103, MPI-103, BBI-103 (Midori Chemical Co., Ltd.). Most preferred are UVI-6974, CD-1010, UVI-6976, Adekaoptomer SP-170, SP-171, CD-1012, as well as MPI-103 and KI78 (hexafluoroantimony sulfonium salts from Asahi Denka). Also suitable is a mixture of S,S,S,S'-tetraphenylthiobis(4,1-phenylene)disulfonium dihexafluoroantimonate and diphenyl(4-phenylthiophenyl)sulfonium hexafluoroantimonate. The cationic photoinitiators can be used either individually or in combination of two or more. The cationic photoinitiators are: -Examples of known cationic photoinitiators include 4-[4-(3-chlorobenzoyl)phenylthio]phenylbis(4-fluorophenyl)sulfonium hexafluoroantimonate, 4-[4-(3-chlorobenzoyl)phenylthio]phenylbis(4-fluorophenyl)sulfonium tetrakis(pentafluorophenyl)borate, 4-[4-(3-chlorobenzoyl)phenylthio]phenylbis(4-fluorophenyl)sulfonium tetrakis(3,5-difluoro-4-methyloxyphenyl)borate, 4-[4-(3-chlorobenzoyl)phenylthio]phenylbis(4-fluorophenyl)sulfonium tetrakis(2,3,5,6-tetrafluoro-4-methyloxyphenyl)borate, and tris(4-(4-acetylphenyl)thiophenyl)sulfonium tetrakis(pentafluorophenyl)borate (BASF's Irgacure® PAG 290), tris(4-(4-acetylphenyl)thiophenyl)sulfonium tris[(trifluoromethyl)sulfonyl]methide (Irgacure® GSID 26-1 from BASF), tris(4-(4-acetylphenyl)thiophenyl)sulfonium hexafluorophosphate (Irgacure® 270 from BASF), and HS-1 available from San-Apro Ltd.

[0092] Known cationic photoinitiators include the following, either alone or in mixtures: Bis[4-diphenylsulfonium phenyl]sulfide bishexafluoroantimonate; thiophenoxyphenylsulfonium hexafluoroantimonate (available as Chivacure 1176 from Chitec), tris(4-(4-acetylphenyl)thiophenyl)sulfonium tetrakis(pentafluorophenyl)borate (Irgacure® PAG 290 from BASF), tris(4-(4-acetylphenyl)thiophenyl)sulfonium tris[(trifluoromethyl)sulfonyl]methide (Irgacure® GSID 26-1 from BASF), and tris(4-(4-acetylphenyl)thiophenyl)sulfonium hexafluorophosphate (Irgacure® 270 from BASF), [4-(1-methylethyl)phenyl](4-methylphenyl)iodonium tetrakis(pentafluorophenyl)borate (Rhodorsil® from Rhodia). 2074), (4-octyloxyphenyl)phenyliodonium hexafluoroantimonate (available from Hampford as OPPIFP5386), 4-[4-(2-chlorobenzoyl)phenylthio]phenylbis(4-fluorophenyl)sulfonium hexafluoroantimonate (available from Adeka as SP-172), Adeka's SP-300, and (PF 6-m (C n F2 n+1 ) m ) - An aromatic sulfonium salt having an anion, where m is an integer from 1 to 5 and n is an integer from 1 to 4 (available as monovalent sulfonium salts CPI-200K or CPI-200S from San-Apro Ltd., TK-1 available from San-Apro Ltd., or HS-1 available from San-Apro Ltd.).

[0093] In one embodiment, the composition may include an aromatic triarylsulfonium salt cationic photoinitiator. One example of a triarylsulfonium tetrakis(pentafluorophenyl)borate cationic photoinitiator is tris(4-(4-acetylphenyl)thiophenyl)sulfonium tetrakis(pentafluorophenyl)borate. Tris(4-(4-acetylphenyl)thiophenyl)sulfonium tetrakis(pentafluorophenyl)borate is commercially known as IRGACURE® PAG-290 and is available from Ciba / BASF. The cationic photoinitiator may be SbF 6 - , P.F. 6 - , B.F. 4 - , (CF 3 CF 2 ) 3 PF 3 - , (C 6 F 5 ) 4 B - , ((CF 3 ) 2 C 6 H 3 ) 4 B - , (C 6 F 5 ) 4 Ga - , ((CF 3 ) 2 C 6 H 3 ) 4 Ga -The cationic photoinitiator may be an aromatic triarylsulfonium salt having an anion represented by the formula: trifluoromethanesulfonate, nonafluorobutanesulfonate, methanesulfonate, butanesulfonate, benzenesulfonate, or p-toluenesulfonate. Another cationic photoinitiator is an aromatic triarylsulfonium cationic photoinitiator having an anion represented by the formula: fluoroalkyl-substituted fluorophosphate. Commercial examples of aromatic triarylsulfonium cationic photoinitiators having fluoroalkyl-substituted fluorophosphate anions are the CPI-200 series (e.g. CPI-200K® or CPI-210S®) or 300 series available from San-Apro Limited.

[0094] The amount of photoinitiator is not believed to be critical, but can vary as may be appropriate depending, among other factors, on the photoinitiator selected, the amount and type of ethylenically unsaturated compound present in the curable composition, the irradiation source and irradiation conditions used, etc. Typically, however, the amount of photoinitiator may be from 0.05% to 5% by weight, or about 0.2-10% by weight, based on the total weight of the curable composition.

[0095] In certain embodiments of the present invention, the curable compositions described herein do not include any initiator and can be cured (at least partially) with electron beam energy. In other embodiments, the curable compositions described herein include at least one free radical initiator that decomposes when heated or in the presence of an accelerator and is chemically curable (i.e., the curable composition does not need to be exposed to light). The at least one free radical initiator that decomposes when heated or in the presence of an accelerator may include, for example, a peroxide compound or an azo compound. Suitable peroxides for this purpose may include any compound, in particular any organic compound having at least one peroxy (-OO-) group, such as dialkyl, diaryl and aryl / alkyl peroxides, hydroperoxides, percarbonates, peresters, peracids, and acyl peroxides. The at least one accelerator may include, for example, at least one tertiary amine and / or other reducing agent based on one or more M-containing salts (such as, for example, carboxylate salts of transition metals such as iron, cobalt, manganese, and vanadium, and combinations thereof). The accelerator may be selected to accelerate the decomposition of the free radical initiator to generate active free radical species at room or ambient temperature such that curing of the curable composition is accomplished without the need to heat or bake the curable composition. In other embodiments, no accelerator is present and the curable composition is heated to a temperature effective to cause decomposition of the free radical initiator and generate free radical species that initiate curing of the polymerizable compounds present in the curable composition.

[0096] Thermal Initiator In some embodiments, the curable compositions described herein further comprise at least one free radical initiator, in addition to the photoinitiator, which decomposes when heated to further chemically cure the composition (i.e., in addition to exposing the curable composition to light). The at least one free radical initiator may also be referred to herein as a thermal initiator. The thermal initiator, which decomposes when heated or in the presence of an accelerator, may comprise, for example, a peroxide compound or an azo compound. Peroxides suitable for this purpose may comprise any compound, particularly any organic compound having at least one peroxy (-OO-) group, such as dialkyl, diaryl and aryl / alkyl peroxides, hydroperoxides, percarbonates, peresters, peracids, and acyl peroxides. The at least one accelerator may comprise, for example, at least one tertiary amine and / or other reducing agent based on one or more M-containing salts, such as, for example, carboxylate salts of transition M-containing salts of iron, cobalt, manganese and vanadium, and combinations thereof. The accelerator may be selected to accelerate the decomposition of the thermal initiator to generate active free radical species at room or ambient temperature such that curing of the hardenable composition is accomplished without the need to heat or bake the hardenable composition. In other embodiments, no accelerator is present and the hardenable composition is heated to a temperature effective to cause decomposition of the thermal initiator and generate free radical species that initiate curing of the polymerizable compounds present in the hardenable composition. Without wishing to be bound by any theory, according to some embodiments, the exotherm produced by photoinduced polymerization provides sufficient heat to decompose such chemical (thermal) free radical initiators.

[0097] The concentration of the thermal initiator in the chemically active radiation curable composition of the present disclosure can be varied as desired depending on the particular compound selected, the type or types of polymerizable compounds present in the chemically active radiation curable composition, the curing conditions utilized, the desired cure rate, among other possible factors. Typically, however, the chemically active radiation curable composition may further comprise 0.05% to 5% by weight, preferably 0.1% to 2% by weight, of a thermal initiator based on the total weight of the curable composition excluding any toughening agents. According to some embodiments, a typical concentration of the thermal initiator may be up to about 15% by weight, based on the total weight of the curable composition excluding any toughening agents. For example, the chemically active radiation curable composition may comprise a total of 0.1 to 10% by weight of a thermal initiator based on the total weight of the curable composition excluding any toughening agents.

[0098] Thus, in various embodiments of the present invention, the curable compositions described herein can be cured by a method selected from the group consisting of radiation curing (UV radiation or electron beam curing), electron beam curing, chemical curing (using free radical initiators that decompose upon heating or in the presence of an accelerator, e.g., peroxide curing), thermal curing, or a combination thereof.

[0099] Filler The curable composition may contain at least one filler, for example at least one opaque filler that is insoluble in the other components of the photocurable composition. In particular, such fillers are not soluble 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 the production of composite materials from the curable composition of the present invention.

[0100] The filler or fillers may be of any suitable shape or form. For example, the filler may take the form of a powder, bead, particulate, particle, granule, wire, fiber, or combinations thereof. If particulate, the particle may be spherical, flat, irregular, or elongated in shape. For example, high aspect particulate fillers may be utilized. Hollow as well as solid fillers are useful in the present invention. According to various embodiments of the present invention, the aspect ratio of the filler (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) may be 1:1 or more, such as 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 10,000:1, at least 100,000:1, at least 500,000:1, at least 1,000:1, or even more (i.e., a virtually infinite aspect ratio). According to other embodiments, the aspect ratio of the filler may be 2:1 or less; 3:1 or less; 5:1 or less; 10:1 or less; 100:1 or less; 1000:1 or less; 10,000:1 or less; 100,000:1 or less; 500,000:1 or less; or 1,000,000:1 or less.

[0101] 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 materials), silylation, oxidation, functionalization, neutralization, acidification, and other chemical modifications, and the like, and combinations thereof.

[0102] The chemical nature of the filler can be varied and selected as desired to impart certain properties or characteristics to the product obtained by curing the light-curable composition. For example, the filler may be inorganic or organic in character. Mixed organic / inorganic fillers can also be used. Carbon-based fillers (e.g., carbon fibers, carbon black, carbon nanotubes) and mineral fillers can also be used. One or more fibrous fillers (i.e., fillers in the form of fibers) can be utilized in particularly preferred embodiments of the present invention. Suitable examples of fibrous fillers include carbon fibers (sometimes referred to as graphite fibers), glass fibers, silicon carbide fillers, boron fibers, alumina fibers, polymeric 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 (length <10 mm), chopped fibers, long fibers (length at least 10 mm), 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 weaves, braided fibers, and knit fibers, and the like, and combinations thereof. Typically, suitable fibers can have a diameter of about 2 to about 20 microns, for example, about 5 to about 10 microns. Hollow and solid fibers can be used; the fibers may be circular or irregular in cross section.

[0103] Examples of other types of fillers that can be used in the curable compositions of the present invention 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, and sulfates (e.g., calcium sulfate), and the like, and combinations thereof.

[0104] In one embodiment, the curable composition comprises one or more fillers with a relatively high loading that are not opaque but allow scattering of light to which the photocurable composition is exposed. For example, light scattering can occur when the refractive index of the filler is different from the refractive index of the portion of the curable composition that does not contain the filler (which before curing is usually a liquid composed of the photocurable compound, the photoinitiator system, and optionally other additives other than the filler). Such fillers may include, for example, glass fillers (e.g., glass fibers) and fillers composed of transparent polymers. In such an embodiment, the curable composition may comprise at least 20% by weight, at least 30% by weight, or at least 40% by weight of such light scattering fillers, based on the total weight of the curable composition.

[0105] Advantageously, the curable composition of the present invention may be formulated to be solvent-free, i.e., to be free of any non-reactive volatile materials. However, in certain other embodiments of the present invention, the curable composition may contain one or more solvents, in particular one or more organic solvents, which may be non-reactive organic solvents. In various embodiments, the solvent may be relatively volatile, for example a solvent with a boiling point of 150° C. or less at atmospheric pressure. In other embodiments, the solvent may have a boiling point of at least 40° C. at atmospheric pressure.

[0106] The solvent may be selected to solubilize one or more components of the hardenable composition and / or to allow adjustment of the viscosity or other flow properties of the hardenable composition.

[0107] However, the curable compositions of the present invention can be selectively 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, a low viscosity reactive diluent, selected to provide a curable composition that has a sufficiently low viscosity in the absence of solvent that the curable composition can be readily applied to form a relatively thin, uniform layer on a substrate surface at a suitable application temperature.

[0108] Suitable solvents may include, for example, organic solvents such as: ketones; esters; carbonates; alcohols; aromatic solvents such as xylene, benzene, toluene, and ethylbenzene; alkanes; glycol ethers; ethers; amides; and combinations thereof.

[0109] In various embodiments of the invention, the curable compositions described herein are formulated to have a viscosity of less than 10,000 cPs, or less than 9000 cPs, or less than 8000 cPs, or less than 7000 cPs, or less than 6000 cPs, or less than 5000 cPs, or less than 4000 cPs, or less than 3000 cPs, or less than 2500 cPs, or less than 2000 cPs, or less than 1500 cPs, or less than 1000 cPs, or even less than 500 cPs, measured at 25° C. using a Brookfield Viscometer, Model DV-II, with a 27 spindle (with a spindle speed that typically varies between 20 and 200 rpm depending on the viscosity). In an advantageous embodiment of the invention, the viscosity of the curable composition is 200 to 1000 cPs at 25° C.

[0110] The curable compositions of the present invention may optionally contain one or more additives in place of or in addition to the ingredients mentioned above, including, but not limited to, antioxidants, UV absorbers, light blocking agents, light stabilizers, antifoaming agents, flow or leveling agents, colorants, pigments, dispersants (wetting agents), slip agents, plasticizers, thixotropic agents, matting agents, impact modifiers, thermoplastics such as acrylics that do not contain any free radically polymerizable functional groups, waxes, or any other variety of additives, including any additives conventionally utilized in coatings, sealants, adhesives, molding, 3D printing, or ink art.

[0111] Use of the curable composition The curable compositions of the invention described herein may be compositions that undergo curing by free radical polymerization or other types of polymerization (e.g., cationic polymerization). End use applications of the curable compositions of the invention include, but are not limited to, inks, coatings, adhesives, 3D printing resins, molding resins, sealants, composites, and the like.

[0112] According to certain embodiments, the curable compositions may be formulated such that they can be fully cured at ambient or room temperature. However, in other embodiments, the curable compositions are formulated such that a partial cure is performed at ambient or room temperature, with additional curing achieved by heating the partially cured composition to an elevated temperature. For example, an initial cure may be performed by exposing the curable composition to light (e.g., ultraviolet light) in an amount effective to (at least partially) react the components of the curable composition that contain polymerizable ethylenically unsaturated functional groups, and additional curing achieved by heating the curable composition to a temperature effective to initiate reaction of the components of the curable composition that contain polymerizable heterocycle-containing moieties. In such cases, curing can be considered to involve two stages: a first cure stage involving radiation (e.g., light) curing, and a second cure stage involving thermal curing.

[0113] Cured compositions prepared from the curable compositions described herein can be used, for example, in three-dimensional articles (wherein the three-dimensional article can consist essentially of or consist of the present cured compositions), coated articles (wherein a substrate is coated with one or more layers of the cured composition), laminated or bonded articles (wherein a first component of the article is laminated or bonded to a second component by the cured composition), composite articles, or printed articles (wherein graphics or the like are imprinted onto a substrate, such as paper, plastic, or an M-containing substrate, using the present cured compositions).

[0114] Curing of the composition according to the invention may be carried out by any suitable method, such as free radical and / or cationic polymerization. One or more initiators, such as free radical initiators (e.g., photoinitiators, peroxide initiators), may be present in the curable composition. Prior to curing, the curable composition may be applied to the substrate surface by any known conventional technique, such as spraying, knife coating, roller coating, casting, drum coating, dipping, jetting, extrusion, gel deposition, and the like, and combinations thereof. Indirect application using a transfer process may also be used. The substrate may be any commercially relevant substrate, such as a high surface energy substrate or a low surface energy substrate, such as a metal substrate or a plastic substrate, respectively. Substrates may include metal, paper, cardboard, glass; thermoplastics such as polyolefins, polycarbonates, acrylonitrile butadiene styrene (ABS), and blends thereof, composites, wood, leather, and combinations thereof. When used as an adhesive, the curable composition may be cured after being placed between two substrates, whereby the cured composition bonds the substrates together to provide an adhesive article.

[0115] Curing may be accelerated or facilitated by providing energy to the curable composition, such as by heating the curable composition and / or by exposing the curable composition to a radiation source, such as visible or UV light, infrared radiation, and / or electron beam radiation. Thus, the cured composition may be considered the reaction product of the curable composition formed by curing.

[0116] Multiple layers of the curable composition according to the present invention can be applied to a substrate surface; the multiple layers can be cured simultaneously (e.g., by exposure to a single dose) or each layer can be cured sequentially before applying an additional layer of the curable composition.

[0117] The curable compositions of the invention described herein are particularly useful as 3D printing resin formulations, i.e. compositions intended for use in the manufacture of three-dimensional articles using 3D printing techniques. Such three-dimensional articles may be free-standing / self-supporting and may consist essentially or exclusively of the cured compositions according to the invention. The three-dimensional articles may also be composites comprising at least one element consisting essentially or exclusively of the cured compositions as already mentioned, as well as at least one additional element composed of one or more materials other than such cured compositions (e.g. metal or thermoplastic components). The curable compositions of the invention are useful for digital light printing (DLP), although other types of three-dimensional (3D) printing processes may also be carried out using the curable compositions of the invention. Non-limiting examples of suitable 3D printing processes include stereolithography (SLA); digital light process (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 build method may be "layer-by-layer" or continuous. The liquid may be in a vat or deposited, for example, by inkjet or gel deposition.

[0118] A method for producing a three-dimensional article using a curable composition according to the present invention comprises the steps of: a) coating a surface with a first layer of a curable composition described herein in any embodiment in liquid form; b) imagewise exposing the first layer to chemically active radiation to form a first exposed image cross-section, the radiation being of sufficient intensity and duration to cause at least partial curing of the first layer in the exposed areas; c) coating an additional layer of a liquid forming curable composition onto the previously exposed image cross section; d) imagewise exposing said additional layer to chemically active radiation to form an additional image section, the radiation being of sufficient intensity and duration to cause at least partial curing of the additional layer in the exposed areas and to adhere the additional layer to the previously exposed image section; e) repeating steps c) and d) as many times as desired to build a three-dimensional article.

[0119] The photocuring step can be carried out by any suitable means, and in some cases will depend on the components present in the curable composition, but in certain embodiments of the present invention, photocuring is accomplished by exposing the layer to be cured to an effective amount of radiation (e.g., electron beam radiation, UV radiation, visible light, etc.) The three-dimensional article that is formed may also be heated to effect thermal curing.

[0120] Thus, in various embodiments, the present invention provides a method comprising the steps of: a) coating a first layer of a curable composition of any embodiment described herein in liquid form onto a surface; b) imagewise exposing said first layer to chemically active radiation to form a first exposed image cross-section, the radiation being of sufficient intensity and duration to cause at least partial curing of the layer in the exposed areas (e.g., at least 50% curing as measured by % conversion of (meth)acrylate double bonds initially present in the composition); c) coating an additional layer of the above curable composition onto the previously exposed image cross section; d) image-wise exposing said additional layer to chemically active radiation to form an additional image section, the radiation being of sufficient intensity and duration to cause at least partial curing (e.g., at least 50% curing as measured by % conversion of (meth)acrylate double bonds initially present in the composition) of the additional layer in the exposed areas and to adhere the additional layer to the previously exposed image section; e) repeating steps c) and d) as many times as desired to build a three-dimensional article.

[0121] The method may include an additional step f) comprising heating the three-dimensional article to a temperature effective to thermally cure the curable composition (i.e., to react the polymerizable oxetanes present in the curable composition with the compound having an epoxy group).

[0122] Although the embodiments have been described herein in a manner that enables a clear and concise specification to be written, it is intended and will be understood that the embodiments may be variously combined or separated without departing from the invention, for example, it will be understood that all preferred features described herein are applicable to all aspects of the invention described herein.

[0123] In some embodiments, the invention herein can be construed to exclude any element or process step that does not materially affect the basic and novel characteristics of the curable composition or the process of using the curable composition. Further, in some embodiments, the invention can be construed to exclude any element or process step not specified herein.

[0124] Although the invention has been illustrated and described herein with reference to specific embodiments, it is not intended that the invention be limited to the details illustrated, but rather, various changes in the details may be made within the scope and range of equivalents of the claims without departing from the invention. EXAMPLES

[0125] The following materials were used in the examples, as shown in Table 1.

[0126] [Table 1A]

[0127] [Table 1B]

[0128] [Table 1C]

[0129] Sample preparation procedure Preparation of formulations in Tables 1 and 2: In 125mL brown glass bottles, SR259, Uvicure S105, and various oxetanes were first charged, followed by SpeedCure ITX, 938, and BKL. A 100g mixture of each sample was sealed in the bottle by securing the lid with white tape. The three glass bottles were then placed on rollers in a 65°C oven for approximately 2 hours until the solution became clear. For Uvicure S150 and S160 samples, due to their high viscosity, a 100g mixture was made in a 250mL metal can by using a mechanical stirrer and heated up to 45°C for approximately 2 hours until the solution became clear.

[0130] Printing of a thin strip sample using a 355nm SLA Viper™ Photopolymer Additive Manufacturing System. a. PET (polyethylene terephthalate) film was cut into a rectangle (approximate size 7.5 inches x 6.5 inches) to fit the shape of the glass (8 inches x 8 inches), and the PET film was adhered to the glass using double-sided tape. b. A non-sticky substance (Rust-o-leum's Never Wet Coat 1 Spray) was sprayed evenly onto the PET film. c.Selected “elevator motion” on the SLA Viper and set the elevator position to 3.3717. d. A pipette was used to dispense 2 mL of liquid onto the glass. e. The first membrane layer was coated using the 5 μm side of the coating applicator. f. Medium (3-5 mJ / cm) to obtain good green strength of the film 2 ) Set up the laser exposure (Ec) and penetration depth (Dp) (20-70 mils) and begin printing. g. Once printing of the first layer was complete, a second 5 μm membrane layer was applied using the 10 μm side of the applicator. h. The printing and thin film application was repeated until the 30 μm side was used. i. Three 4 inch by 0.5 inch untreated tensile thin strips were printed in this manner, 6 layers per print, 5 μm each, and one 35 mm by 12 mm DMA strip. j. The uncured liquid resin was drained, washed with isopropyl alcohol and dried in air. k. Carefully peel each narrow strip from the PET film. l. At 100% strength, the above narrow strips were post cured for 15 minutes at 30° C. (Envision TECPCA 2000 curing unit). m. Samples were stored at 23±2° C. and 50±10% relative humidity conditions for at least 7 days prior to testing.

[0131] Test Method: LED-DSC Test A photodifferential scanning calorimeter (DSC) with a customized 365 nm LED lamp setup was used for the tests. All photopolymerization kinetics measurements were performed using a TA Instruments Q2000 DSC unit. To ensure an exact fit with the Digital Light Labs 365 nm lamp Accucure ULM-2-365 or 405 nm lamp Accucure ULM-2-405, the lamp holder of the DSC unit can be customized and printed from Arkema N3xtDimension® engineering resin N3D-TOUGH784. The LED light was automatically turned on by connecting the "Event" outlet of the DSC unit to the Accure Photo Rheometer's Ultraviolet Illumination & Measurement System. The LED exposure can be programmed by using "Event" on or off from the Photo DSC software, while the light intensity can be preset from the Accure Photo Rheometer's Ultraviolet Illumination & Measurement System. For the measurements, approximately 5 mg of liquid sample was placed in the center of the T130522 DSC Tzero pan and 50 mW / cm 2 365 nm or 405 nm LED light at 50 mL / min N 2 After curing by exposure at 40° C. for 5 min under flow rate, a second exposure was performed under the same conditions to determine and subtract the blank. The resulting heat flow (W / g) curves were collected and analyzed for the maximum heat flow peak value and maximum peak time.

[0132] Real-time FTIR (Fourier transform infrared spectroscopy) A real-time Fourier transform infrared (RT-FTIR) with attenuated total reflectance (ATR) setup 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 of the ART platform of the FTIR unit was customized and printed from Arkema N3xtDimension® engineering resin N3D-TOUGH784 to ensure an accurate fit with the Digital Light Labs 365 nm lamp Accucure ULM-2-365 or 405 nm lamp Accucure ULM-2-405. The LED light was turned on manually by connecting to an Ultraviolet Illumination & Measurement System. The LED exposure can be programmed by the AccuCure software. For the measurements, a droplet of liquid sample was placed at the center of the ATR crystal. A 3 mil thin film was coated by a customized coating applicator (BYK 3 mil WFM, G1046). The LED lamp with the holder was placed on top of the ART platform. A real-time FTIR scan was then started to collect the IR spectrum. Once the liquid spectrum was collected, the FTIR scan was started at 50 mW / cm 2 The photopolymerization was initiated for a total of 200 seconds by turning on a high-intensity LED light source. Both the epoxide and oxetane were ring-opened to form C-O-C bonds, resulting in a photopolymerization reaction at approximately 1100 cm. -1 The amplification of the COC IR peak height at approx. 1727 cm -1 The C=O reference peak height at 1100 cm was also collected. -1 / 1727cm -1 was calculated to evaluate the cationic curing rate.

[0133] Dynamic Mechanical Analysis (DMA) Testing DMA tests were performed using a TA Instruments DMAQ800 to determine the change in mechanical properties of each cured DMA strip over the temperature range. The DMA machine was run from -150°C to 250°C at 3°C / min with a frequency of 1 Hz. Storage modulus (G'), loss modulus (G") and tangent (delta) curves are measured over the temperature range.

[0134] Tensile Test Tensile properties were measured using an Instron 5966 with a tensile test fixture and a load of 10 kN. Thin strips were prepared for tensile properties. Six specimens were prepared for each sample, and the test speed for tensile testing was set at 5 mm / min. Tests were performed according to the ASTM D882-10 protocol.

[0135] Examples and Performance Table 2 lists the formulations, cure rates, and mechanical properties of the cured compositions for formulations containing 10 wt% acrylate based on the total weight of the composition. The components of each formulation are listed in Table 1 (amounts are given in wt% based on the total weight of the composition). The oxetane / (oxetane+epoxy) ratio is expressed as the wt% of oxetane based on the combined weight of oxetane and epoxy.

[0136] [Table 2]

[0137] Table 3 lists the formulations, cure rates, and mechanical properties of the cured compositions for a formulation containing 65 wt% acrylate based on the total weight of the composition. The components of each formulation are listed in Table 1 (amounts are given in wt% based on the total weight of the composition). The oxetane / (oxetane+epoxy) ratio is expressed as the wt% of oxetane based on the combined weight of oxetane and epoxy.

[0138] [Table 3]

[0139] The results shown in Tables 2 and 3 highlight the surprising finding that the cure rate was greatest, as indicated by the high peak height ratios and low peak times, for compositions in which the oxetane component comprised approximately 80% of the combined weight of the epoxy and oxetane components in the composition.

[0140] Tables 4 and 5 show the variation between 20% and 80% by weight of oxetane based on the combined weight of epoxy and oxetane in the composition. The components of each formulation are listed in Table 1 (amounts are given in weight % based on the total weight of the composition). The oxetane / (oxetane+epoxy) ratio is expressed as weight % of oxetane based on the combined weight of oxetane and epoxy.

[0141] [Table 4]

[0142] [Table 5]

Claims

1. a) one or more oxetane-functional compounds; b) one or more epoxy-functional compounds; c) one or more (meth)acrylate functional compounds; d) at least one photoinitiator; and and optionally at least one additive, 55% to 90% by weight, preferably 60% to 90% by weight, more preferably 70% to 90% by weight, of one or more oxetane-functional compounds based on the total weight of the one or more oxetane-functional compounds and the one or more epoxy-functional compounds in the composition; and 15% to 95% by weight of one or more (meth)acrylate-functional compounds, based on the total weight of the composition; Chemical actinic radiation curable composition.

2. 2. The chemically active radiation curable composition of claim 1, comprising 20% ​​to 90% by weight, more preferably 20% to 60% by weight, of one or more (meth)acrylate functional compounds, based on the total weight of the composition.

3. 3. The chemically active radiation curable composition according to claim 1 or 2, comprising 75% to 85% by weight of the one or more oxetane functional compounds, based on the total weight of the one or more oxetane functional compounds and the one or more epoxy functional compounds in the composition.

4. 4. The chemically active radiation curable composition of claim 1, wherein the one or more oxetane functional compounds comprise at least one of a monofunctional oxetane compound or a difunctional oxetane compound.

5. 5. The chemically active radiation curable composition of claim 1, wherein the one or more epoxy functional compounds comprise at least one of a monofunctional epoxy compound or a difunctional epoxy compound.

6. 6. The chemically active radiation curable composition of any one of claims 1 to 5, wherein the one or more oxetane functional compounds comprise at least one of 3-ethyl-3-hydroxymethyl-oxetane, 3-ethyl-3-[(phenylmethoxy)methyl]-oxetane, bis[1-ethyl(3-oxetanyl)]methyl ether, 1,4-bis[(3-ethyl-3-oxetanylmethoxy)methyl]benzene, 4,4-bis(3-ethyl-3-oxetanyl)methoxymethyl]biphenyl, 3-ethyl-3-(methacryloyloxy)methyloxetane, trimethylolpropane tris(3-ethyl-3-oxetanylmethyl)ether, or combinations thereof.

7. 7. The chemically active radiation curable composition of any one of claims 1 to 6, wherein the one or more epoxy functional compounds comprise at least one of epoxidized vegetable oils, monoepoxides, diepoxides, polyepoxides, alicyclic polyglycidyl compounds, cycloaliphatic polyepoxides, epoxy ethers, aromatic epoxies, aliphatic epoxies, aliphatic glycidyl ethers, linear, branched epoxidized polyenes, or combinations thereof.

8. 8. The chemically active radiation curable composition of any one of claims 1 to 7, wherein the one or more epoxy functional compounds comprise at least one of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, bis(3,4-epoxy-cyclohexyl)adipate, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate modified caprolactone, or combinations thereof.

9. 9. The chemically active radiation curable composition of claim 1, wherein the epoxide and / or oxetane compound comprises one or more (meth)acrylate-functional epoxides, one or more (meth)acrylate-functional oxetanes, one or more epoxy-functional oxetanes, or a combination thereof.

10. 10. The chemically active radiation curable composition of claim 1 further comprising one or more thermal initiators.

11. 11. The chemically active radiation curable composition of claim 1 further comprising one or more hydroxyl functional compounds.

12. 12. The chemically active radiation curable composition according to any one of claims 1 to 11, further comprising at least one filler.

13. 13. The chemically active radiation curable composition of claim 1, wherein the photoinitiator comprises at least one of a cationic photoinitiator or a free radical photoinitiator.

14. 1. A method for producing a hardened material, comprising the steps of: A method comprising the step of curing with chemically active radiation a chemically active radiation curable composition according to any one of claims 1 to 13.

15. 1. A method of producing a 3D printed article, comprising: a) providing a first layer of a chemically active radiation curable composition according to any one of claims 1 to 13 on a surface; b) at least partially curing the first layer to provide a cured first layer; c) providing a second layer of said chemically active radiation curable composition over the cured first layer; d) at least partially curing the second layer to provide a cured second layer adhered to the cured first layer; e) repeating steps c) and d) as many times as desired to build a 3D printed article. A method comprising:

16. 16. The method of claim 15, further comprising step f) comprising heating the 3D printed article to a temperature effective to thermally cure the curable composition.

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