Curable composition

Abstract

A curable composition comprising: A) a radically polymerizable resin comprising at least one (meth) acrylate monomer, at least one (meth) acrylate oligomer, or both; b) a cationically polymerizable resin; c) a free radical photoinitiator; d) a photoacid generator; and E) a polyol; wherein the weight ratio of A: B is 32: 1 to 2: 1. Methods of using the curable composition include use thereof as a dual curable pressure sensitive adhesive having good peel and cohesive strength.

Description

Technical Field

[0001] Embodiments of this disclosure relate to photocurable compositions, and more specifically to curable compositions capable of undergoing multiple curing mechanisms to provide pressure-sensitive adhesives. Background Technology

[0002] Pressure-sensitive adhesives (PSA) allow users to press the adhesive onto a surface and form a bond using pressure without the need for additional heat or energy. Typically, PSAs are soft, flexible, and deformable solids that are safe to use and easy to handle. PSAs are widely used in many industries, including tapes and labels, automotive, electronics, and medical devices.

[0003] Traditional PSAs contain a variety of different polymer compositions dissolved in a solvent, such as water or an organic solvent. One class of PSAs is known as photocurable PSAs. Compared to solvent-based PSAs, photocurable PSAs have attracted attention due to their potential for improved cost, curing efficiency, and a generally better environmental footprint. Solvent-based PSAs require significant time and energy to coat the PSA composition and evaporate the solvent. When organic solvents are used, solvent evaporation generates a class of pollutants called volatile organic compounds (VOCs), thus requiring expensive filtration and solvent recovery mechanisms. While water-based solvents avoid the VOC problems of organic solvents, they require even more energy for the drying process.

[0004] Historically, photocurable PSA has had limited levels of peel and shear strength (i.e., similar to the adhesive strength level of typical PSA). Summary of the Invention

[0005] Such a curable composition is desired, combining the ease of use of conventional pressure-sensitive adhesives, the easy curing properties of UV-PSA, and overcoming the problem of insufficient adhesive strength. This need can be met by the curable compositions disclosed herein, which comprise a free-radical polymerizable resin, a cationic polymerizable resin, a free-radical photoinitiator, and a photoacid generator.

[0006] Exemplary embodiments include a curable composition comprising: A) a free radical polymerizable resin comprising at least one (meth)acrylate monomer, at least one (meth)acrylate oligomer, or both; B) a cationic polymerizable resin; C) a free radical photoinitiator; D) a photoacid generator; and E) a polyol; wherein the weight ratio of A:B is from 32:1 to 2:1.

[0007] These and other embodiments are described in more detail throughout this disclosure. The foregoing general description and the following detailed description provide exemplary embodiments and offer a general overview or framework for understanding the nature and characteristics of the technology. Furthermore, these descriptions are merely illustrative and are not intended to limit the scope of the claims in any way. Detailed Implementation

[0008] There is a need in the art for a curable composition that combines the ease of use of pressure-sensitive adhesives, the easy curing properties of UV-PSA, and overcomes the problem of insufficient adhesive strength or cohesive strength. One or more embodiments disclosed herein meet this need by providing a curable composition comprising a free radical polymerizable resin, a cationic polymerizable resin; a free radical photoinitiator; a photoacid generator; and a polyol.

[0009] "Photochemical light source" refers to an electromagnetic radiation source that produces at least a portion of its electromagnetic radiation in the ultraviolet range (100 nm to 400 nm).

[0010] The term "aliphatic" refers to saturated and unsaturated hydrocarbons, straight-chain (i.e., unbranched) or branched, cyclic or acyclic, excluding aromatic groups. The term "aliphatic" includes, but is not limited to, alkyl, alkenyl, and alkynyl groups. Therefore, illustrative aliphatic groups include, but are not limited to, for example, methyl, ethyl, n-propyl, isopropyl, allyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, sec-pentyl, etc. Isopentyl, tert-pentyl, n-hexyl, sec-hexyl, alkenyl such as vinyl, propenyl, 1-methyl-2-buten-1-yl, and alkynyl such as ethynyl, 2-propynyl (propynyl), and 1-propynyl.

[0011] "Catically polymerizable resins" refer to resins that form polymers in the presence of cations.

[0012] "Cureable composition" refers to a composition whose properties are altered based on a stimulus. Generally, the cureable compositions of this disclosure are cured by polymerization and / or crosslinking. Generally, those cureable compositions cure upon the addition of energy to the system, which may be in the form of photochemical light, heat, or both. Typically, when the compounds in the cureable composition contain carbon-carbon double bonds, polymerization (curing) involves the reaction of such carbon-carbon double bonds.

[0013] "Epoxide" refers to a compound containing one or more epoxy groups, such as a monomer.

[0014] The term "photoinitiator" refers to any type of substance that, upon exposure to radiation (e.g., photochemical radiation), forms a substance that initiates a reaction and cures a polymeric organic substance in a curable composition.

[0015] "Free radical photoinitiator" refers to a compound that undergoes a photoreaction upon absorbing light, producing reactive free radicals. These reactive substances then initiate the curing (polymerization) of the reactive components of the curable composition.

[0016] "Free radical polymerizable resin" refers to a resin that can polymerize when exposed to free radicals.

[0017] The term "(meth)acrylate group" refers to either an acrylate group or a methacrylate group. An acrylate group corresponds to a group with the formula -OC(=O)-CH=CH2. A methacrylate group corresponds to a group with the formula -OC(=O)-C(CH3)=CH2.

[0018] "Monofunctional" refers to a compound that has a single functional group. For example, a monofunctional (meth)acrylate monomer is a monomer that has a single (meth)acrylate group.

[0019] A "monomer" is a molecule having one or more polymerizable functional groups. Monomers have a single molecular weight, typically below 1000 g / mol, preferably from 100 to 950 g / mol. As is generally recognized in the art, commercial products of a particular monomer may contain impurities or other chemicals.

[0020] "Number-average molecular weight" or "M n "Number-average molecular weight" refers to the statistical average molecular weight of polymer chains in a sample or group. Unless otherwise explicitly stated, the number-average molecular weights reported herein were determined using size exclusion chromatography (SEC) with poly(methyl methacrylate) reference standards and tetrahydrofuran as solvent.

[0021] "Oligomer" refers to a molecule with a molecular weight distribution and may or may not have one or more polymerizable functional groups. Oligomers can be the reaction products of two or more monomers and typically have a number-average molecular weight of 500 g / mol or greater, preferably from 500 g / mol to 30,000 g / mol, more preferably from 1,000 g / mol to 8,000 g / mol. Oligomers may not always have a single molecular weight.

[0022] "Photoacid generators" are compounds that release protons or produce other cations or acidic compounds when exposed to light.

[0023] "Polyols" refer to alcohols that have more than one hydroxyl group.

[0024] Embodiments of this disclosure relate to curable compositions comprising: A) a free radical polymerizable resin comprising at least one (meth)acrylate monomer, at least one (meth)acrylate oligomer, or both; B) a cationic polymerizable resin; C) a free radical photoinitiator; D) a photoacid generator; and E) a polyol, wherein the weight ratio of A:B is from 32:1 to 2:1.

[0025] The curable composition comprises A) a free radical polymerizable resin. When combined with a free radical photoinitiator (C) and exposed to photochemical radiation in a first wavelength range, the free radical polymerizable resin polymerizes, thereby forming a pressure-sensitive adhesive from the curable composition.

[0026] The free radical polymerizable resin may contain at least one (meth)acrylate monomer, at least one (meth)acrylate oligomer, or both, preferably both. The at least one (meth)acrylate monomer may be monofunctional (e.g., containing a single (meth)acrylate group) or polyfunctional (e.g., containing more than one (meth)acrylate group), including difunctional monomers or combinations thereof. In embodiments, most or all of the (meth)acrylate monomers used are monofunctional; for example, based on the total weight of the (meth)acrylate monomers, 95% to 99% by weight of the (meth)acrylate monomers are monofunctional, and the remainder are difunctional. The at least one (meth)acrylate oligomer may be polyfunctional, including difunctional monomers. In embodiments, most or all of the (meth)acrylate oligomers used are difunctional; for example, based on the total weight of the (meth)acrylate oligomers, 95% to 100% by weight of the (meth)acrylate oligomers are difunctional. As is well known, (meth)acrylate oligomers can have non-integer average functionality (e.g., between 1.9 and 2.1), and such (meth)acrylate oligomers are applicable herein.

[0027] The categories of (meth)acrylate oligomers are diverse and well known to those skilled in the art. Anticipated oligomer categories include urethane (meth)acrylates, (meth)acrylated epoxy (“epoxy (meth)acrylates”), (meth)acrylated polyesters, and (meth)acrylated siloxanes.

[0028] In addition to (meth)acrylate groups, at least one (meth)acrylate oligomer may contain a urethane linker. The at least one (meth)acrylate oligomer may be an aliphatic urethane (meth)acrylate oligomer. A suitable (meth)acrylate oligomer is available under the trade name CN9018 from Sartamomer Americas.

[0029] The categories of (meth)acrylate monomers are diverse and well known to those skilled in the art. A wide range of (meth)acrylate monomers may be used herein. The at least one (meth)acrylate monomer may comprise a first (meth)acrylate monomer and a second (meth)acrylate monomer. It should be understood that a free radical polymerizable resin may comprise a first (meth)acrylate monomer, a second (meth)acrylate monomer, or a first (meth)acrylate monomer and a second (meth)acrylate monomer, and optionally other monomers. In some embodiments, a free radical polymerizable resin may comprise at least one (meth)acrylate oligomer, a first (meth)acrylate monomer, and a second (meth)acrylate monomer.

[0030] Examples of suitable monofunctional (meth)acrylate monomers include, but are not limited to, (meth)acrylates of aliphatic alcohols (wherein the aliphatic alcohol may be linear, branched, or alicyclic, and may be a monohydric or polyhydric alcohol (e.g., a diol), provided that only one hydroxyl group is (meth)acrylated); (meth)acrylates of aromatic alcohols (e.g., phenols, including alkylated phenols); (meth)acrylates of alkylaryl alcohols (e.g., benzyl alcohol); and (meth)acrylates of oligomeric glycols and polymeric glycols (such as diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol, and polypropylene glycol). (Meth)acrylates; (meth)acrylates of monoalkyl ethers of glycols and oligomeric glycols; (meth)acrylates of alkoxylated (e.g., ethoxylated and / or propoxylated) aliphatic alcohols (wherein the aliphatic alcohol may be linear, branched or alicyclic, and may be a monohydric or polyhydric alcohol (e.g., a diol), provided that only one hydroxyl group of the alkoxylated aliphatic alcohol is (meth)acrylated); (meth)acrylates of alkoxylated (e.g., ethoxylated and / or propoxylated) aromatic alcohols (such as alkoxylated phenols); caprolactone mono(meth)acrylates; etc.

[0031] The following compounds are specific examples of monofunctional (meth)acrylate monomers applicable to component A): methyl (meth)acrylate; ethyl (meth)acrylate; n-propyl (meth)acrylate; n-butyl (meth)acrylate; isobutyl (meth)acrylate; n-hexyl (meth)acrylate; 2-ethylhexyl (meth)acrylate; n-octyl (meth)acrylate; isooctyl (meth)acrylate; n-decyl (meth)acrylate; n-dodecyl (meth)acrylate; tridecyl (meth)acrylate; tetradecyl (meth)acrylate; hexadecyl (meth)acrylate; 2-hydroxyethyl (meth)acrylate; 2- and 3-hydroxypropyl (meth)acrylate; 2-methoxyethyl (meth)acrylate; 2-ethoxyethyl (meth)acrylate; 2- and 3-ethoxypropyl (meth)acrylate; tetrahydrofurfuryl (meth)acrylate; alkoxylated tetrahydrofurfuryl (meth)acrylate; 2-(2-ethoxyethyl)acrylate (Oxyethyl) acrylate; (meth)cyclohexyl acrylate; (meth)glycidyl acrylate; (meth)isodecyl acrylate; (meth)lauryl acrylate; (meth)2-phenoxyethyl acrylate; alkoxylated phenol (meth)acrylate; alkoxylated nonylphenol (meth)acrylate; cyclic trimethylolpropane acetal (meth)acrylate; (meth)isoborneol acrylate; tricyclodecane methanol (meth)acrylate; tert-butylcyclohexanol (meth)acrylate; trimethylcyclohexanol (meth)acrylate; diethylene glycol monomethyl ether (meth)acrylate; diethylene glycol monoethyl ether (meth)acrylate; diethylene glycol monobutyl ether (meth)acrylate; triethylene glycol monoethyl ether (meth)acrylate; ethoxylated (meth)lauryl acrylate; methoxylated polyethylene glycol (meth)acrylate; hydroxyethyl-butylcarbamate (meth)acrylate; 3-(2-hydroxyalkyl)oxazolidinone (meth)acrylate; and combinations thereof.

[0032] As mentioned above, (meth)acrylate monomers can be multifunctional. Multifunctional (meth)acrylate monomers can have 2 to 6 (meth)acrylate groups, particularly 2 or 3 (meth)acrylate groups. Examples of suitable multifunctional (meth)acrylate monomers include bisphenol A di(meth)acrylate; hydrogenated bisphenol A di(meth)acrylate; ethylene glycol di(meth)acrylate; diethylene glycol di(meth)acrylate; triethylene glycol di(meth)acrylate; tetraethylene glycol di(meth)acrylate; polyethylene glycol di(meth)acrylate; propylene glycol di(meth)acrylate; dipropylene glycol di(meth)acrylate; tripropylene glycol di(meth)acrylate; tetrapropylene glycol di(meth)acrylate; polypropylene glycol di(meth)acrylate; polytetramethylene glycol di(meth)acrylate; poly(ethylene glycol di(meth)acrylate; poly(ethylene glycol di(meth)acrylate); ... Methacrylates; 1,2-Butanediol di(meth)acrylate; 2,3-Butanediol di(meth)acrylate; 1,3-Butanediol di(meth)acrylate; 1,4-Butanediol di(meth)acrylate; 1,5-Pentanediol di(meth)acrylate; 1,6-Hexanediol di(meth)acrylate; 1,8-Octanediol di(meth)acrylate; 1,9-Nonanediol di(meth)acrylate; 1,10-Nonanediol di(meth)acrylate; 1,12-Dodecanediol di(meth)acrylate; Neopentylene glycol di(meth)acrylate; 2-Methyl-2,4-pentanediol di(meth)acrylate; polybutadiene di(meth)acrylate; cyclohexane-1,4-diethanol di(meth)acrylate; tricyclodecanediethanol di(meth)acrylate; metal di(meth)acrylates; modified metal di(meth)acrylates; glycerol di(meth)acrylates; glycerol tri(meth)acrylates; trimethylolethane tri(meth)acrylates; trimethylolethane di(meth)acrylates; trimethylolpropane tri(meth)acrylates; trimethylolpropane di(meth)acrylates; pentaerythritol di(meth)acrylates 2,4-hydroxyethyl isocyanurate tri(meth)acrylate; pentaerythritol tri(meth)acrylate; pentaerythritol tetra(meth)acrylate, di(trimethylolpropane)diacrylate; di(trimethylolpropane)triacrylate; di(trimethylolpropane)tetraacrylate, sorbitol penta(meth)acrylate; di(pentaerythritol)tetraacrylate; di(pentaerythritol)pentaacrylate; di(pentaerythritol)hexa(meth)acrylate; tri(2-hydroxyethyl)isocyanurate tri(meth)acrylate; and their alkoxylated (e.g., ethoxylated and / or propoxylated) derivatives; and combinations thereof.Examples of other suitable monofunctional (meth)acrylate monomers include, for example, caprolactone (meth)acrylate, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, isooctyl (meth)acrylate, 2-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isodecanyl (meth)acrylate, ethoxyethoxyethyl (meth)acrylate, neopentyl glycol (meth)acrylate and their alkoxylated analogs, and caprolactone-based (meth)acrylates (“caprolactone adducts of (meth)hydroxyalkyl acrylates”) and combinations thereof prepared by adding 1, 2, 3 or more moles of caprolactone to hydroxyalkyl (meth)acrylates such as hydroxyethyl (meth)acrylate.

[0033] In the embodiments, the first (meth)acrylate monomer may comprise an isobornyl group. The first (meth)acrylate monomer may be monofunctional (having a single (meth)acrylate group). The first (meth)acrylate monomer may comprise a single isobornyl group and a single acrylate group. The (meth)acrylate monomer comprising an isobornyl group may be an isobornyl acrylate having structure (I). Suitable commercially available monofunctional acrylate monomers of structure (I) include SR506A from Sartamomer Americas.

[0034] Structure (I)

[0035] The second (meth)acrylate monomer may contain a furfuryl group. The second (meth)acrylate monomer may be monofunctional (having a single (meth)acrylate group). The second (meth)acrylate monomer may contain both a single acrylate group and a single furfuryl group. In an embodiment, the second (meth)acrylate monomer may be alkoxylated tetrahydrofurfuryl acrylate. In an embodiment, the second (meth)acrylate monomer may have structure (II).

[0036] Structure (II)

[0037] A suitable second acrylate monomer can be purchased from Sartamomer Americas under the trade name SR611.

[0038] In an embodiment, the curable composition may comprise a first (meth)acrylate monomer and a second (meth)acrylate monomer. The ratio of the first (meth)acrylate monomer to the second (meth)acrylate monomer may be 2:1 to 1:2, 8:5 to 1:2, 6:5 to 1:2, 4:5 to 1:2, 3:5 to 1:2, 8:5 to 5:8, 6:5 to 5:6, 11:10 to 10:11, 2:1 to 5:8, 2:1 to 6:5, 2:1 to 5:4, 2:1 to 5:3, or any subset thereof. In an embodiment, the ratio of the first (meth)acrylate monomer to the second (meth)acrylate monomer may be 9:10 to 11:10.

[0039] In particular, at least one (meth)acrylate monomer may be selected from isobornyl (meth)acrylate (preferably IBOA), tetrahydrofurfuryl alkoxylated (meth)acrylate (preferably THFA), or both.

[0040] Based on the total weight of the free radical polymerizable resin (A), the free radical polymerizable resin (A) may contain at least 80% by weight, for example, at least 90% by weight, at least 95% by weight, or at least 99% by weight, of at least one (meth)acrylate monomer, at least one (meth)acrylate oligomer, or both (preferably both). The free radical polymerizable resin (A) may contain other olefinically unsaturated materials, such as allyl, malonate, and itaconic acid esters. The free radical polymerizable resin (A) may consist substantially of a combination or composition of at least one (meth)acrylate monomer and at least one (meth)acrylate oligomer. The weight ratio of at least one (meth)acrylate monomer to at least one (meth)acrylate oligomer in the free radical polymerizable resin (A) may vary over a wide range, for example, from 1:9 to 49:1, from 1:4 to 39:1, from 1:2 to 19:1, or from 1:1 to 19:1.

[0041] The curable composition comprises C) a free radical photoinitiator. The free radical photoinitiator is sensitive to photochemical radiation in a first wavelength range. The free radical photoinitiator is operable to cure a free radical polymerizable resin. Typically, free radical photoinitiators can employ two different modes of action and are classified as Norrish Type I and Norrish Type II photoinitiators based on their mode of action. In some embodiments, the free radical photoinitiator includes a Norrish Type I photoinitiator, a Norrish Type II photoinitiator, or both.

[0042] As used herein, the term "activity" in relation to Norrish type I and Norrish type II activity is intended to refer to Norrish photoinitiation and similar reactions. For example, a photoinitiator with Norrish type I activity would be one that, upon exposure to photochemical radiation in a first wavelength range, undergoes a cleavage reaction to form two radical fragments of the original photoinitiator. For an initiator with Norrish type II activity, exposure to photochemical radiation in the first wavelength range induces the formation of a radical substance that can abstract hydrogen to generate a second radical substance capable of initiating photopolymerization. The Norrish type I and Norrish type II mechanisms are known to those skilled in the art. Free radical photoinitiators suitable for the curable compositions disclosed herein include, but are not limited to, benzoin, benzoin ether, acetophenone, α-hydroxyacetophenone, benzyl, benzyl ketal, anthraquinone, phosphine oxide, acylphosphine oxide, α-hydroxy ketone, phenylglyoxylate, α-amino ketone, benzophenone, thioxanthone, xanthones, acridine derivatives, phenazine derivatives, quinoxaline derivatives, triazine compounds, benzoylcarbamates, aromatic oximes, metallocenes, acylsilyl or acylgermanyl compounds, camphorquinone, their polymeric derivatives, and mixtures thereof.

[0043] Examples of suitable free radical photoinitiators include, but are not limited to, 2-methylanthraquinone, 2-ethylanthraquinone, 2-chloroanthraquinone, 2-benzylanthraquinone, 2-tert-butylanthraquinone, 1,2-benzo-9,10-anthraquinone, benzyl, benzoin, benzoin ether, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, α-methylbenzoin, α-phenylbenzoin, michidone, acetophenone such as 2,2-dialkoxybenzophenone and 1-hydroxyphenyl ketone, benzophenone, 4,4'-bis-( Diethylamino)benzophenone, acetophenone, 2,2-diethyloxyacetophenone, diethyloxyacetophenone, 2-isopropylthioxanthone, thioxanthone, diethylthioxanthone, 1,5-acetylnaphthalene, benzoyl ketone, α-hydroxy ketone, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, benzyl dimethyl ketal, 2,2-dimethoxy-1,2-diphenyl ethyl ketone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinoacetone-1, 2-Hydroxy-2-methyl-1-phenylpropanone, oligo-α-hydroxy ketone, benzoylphosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, ethyl (2,4,6-trimethylbenzoyl)phenylphosphine sulfate, anisolein, anthraquinone, anthraquinone-2-sulfonic acid, sodium salt monohydrate, (benzene)tricarbonylchromium, benzoyl, benzoin isobutyl ether, benzophenone / 1-hydroxycyclohexylphenyl ketone, 50 / 50 blend, 3,3',4,4'-di Benzyl tetracarboxylic acid dianhydride, 4-benzoylbiphenyl, 2-benzyl-2-(dimethylamino)-4'-morpholinophenylbutanone, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(dimethylamino)benzophenone, camphorquinone, 2-chlorothiazol-9-one, dibenzocycloheptenone, 4,4'-dihydroxybenzophenone, 2,2-dimethoxy-2-phenylacetophenone, 4-(dimethylamino)benzophenone, 4,4'-dimethylbenzoin, 2 5-Dimethylbenzophenone, 3,4-Dimethylbenzophenone, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide / 2-hydroxy-2-methylphenylacetone, 50 / 50 blend, 4'-ethoxyacetophenone, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, ferrocene, 3'-hydroxyacetophenone, 4'-hydroxyacetophenone, 3-hydroxybenzophenone, 4-hydroxybenzophenone Ketones, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methylphenylacetone, 2-methylbenzophenone, 3-methylbenzophenone, methyl benzoyl carbamate, 2-methyl-4'-(methylthio)-2-morpholinophenylacetone, phenanthrenequinone, 4'-phenoxyacetophenone, (cumene)cyclopentadienyl iron(ii) hexafluorophosphate, 9,10-diethoxy and 9,10-dibutoxyanthracene, 2-ethyl-9,10-dimethoxyanthracene, thioxanthone-9-one and combinations thereof.

[0044] Suitable free radical photoinitiators include benzophenone (e.g., available from Sartomer Americas under the trademark Speedcure). TM BP, Speedcure TM 7005 and Speedcure TM Those obtained from 7006), thioxanthone (e.g., available from Sartomer Americas under the trademark Speedcure) TM 7010 and Speedcure TM ITX), α-hydroxyacetophenone, acylphosphine oxide (e.g., available from Sartamomer Americas under the trademark Speedcure) TM BPO, Speedcure TM TPO and Speedcure TM TPO-L (obtained) and its combinations.

[0045] Free radical photoinitiators can be acylphosphine oxides. As used herein, the term "phosphine oxide" refers to a compound containing a -P (=O)- group. Acylphosphine oxides may have structure (III).

[0046] Structure (III)

[0047] The free radical photoinitiator can be phenylacetone, such as phenylacetone with structure (IV).

[0048] Structure (IV)

[0049] The free radical photoinitiator can be a blend of acylphosphine oxide and phenylacetone, for example, acylphosphine oxide having structure (III) and phenylacetone having structure (IV).

[0050] Free radical photoinitiators are sensitive to photochemical radiation within a first wavelength range. Sensitivity to photochemical radiation within a first wavelength range means that when the free radical photoinitiator is exposed to photochemical radiation within this range, it generates free radicals. The first wavelength range can include long-wavelength ultraviolet (UV) light, such as light with wavelengths greater than 365 nm, and can be from 365 nm to 450 nm. In some embodiments, the photochemical radiation within the first wavelength range can be generated by LED lights, such as LEDs emitting at 365 nm, 395 nm, 405 nm, or combinations thereof.

[0051] A free radical photoinitiator may have a maximum absorption value within a defined first wavelength range. A free radical photoinitiator may also have additional maximum absorption values ​​outside the defined first wavelength range. In addition to light within the first wavelength range, a free radical photoinitiator may be sensitive to wavelengths defined outside the first wavelength range, including those within a second wavelength range.

[0052] The curable composition comprises B) a cationically polymerizable resin. The term "cationically polymerizable compound" refers to a compound containing polymerizable functional groups that polymerize via a cationic mechanism; for example, the cationically polymerizable group may contain heterocyclic groups or carbon-carbon double bonds substituted with electron-donating groups. In a cationic polymerization mechanism, a cationic initiator accepts a charge from a cationically polymerizable compound, and then the cationic initiator becomes reactive, leading to chain growth through reaction with another cationically polymerizable compound. Without being theoretically limited, it appears that cationically polymerizable resins, when used with photoacid generators, polymerize more slowly than radically polymerizable resins. However, it appears that the bonds formed by cationically polymerizable resins are stronger than those formed by the polymerization of radically polymerizable resins.

[0053] The cationicly polymerizable compounds may be selected from epoxides, oxetanes, vinyl ethers, vinylamides, oxetanes, cyclic acetals, cyclic lactones, thiohexacyclopropanes, thiethanes, spirocyanates, olefinic unsaturated compounds other than (meth)acrylates, their derivatives, and mixtures thereof.

[0054] Epoxides can include aromatic epoxides, alicyclic epoxides, oxetanes, and mixtures thereof. Suitable epoxy-functionalized compounds capable of cationic polymerization include glycidyl ethers, particularly mono-, di-, tri-, and polyglycidyl ether compounds, and alicyclic ether compounds, including those containing carboxylic acid residues, such as alkyl carboxylic acid residues, alkylcycloalkyl carboxylic acid residues, and dialkyl dicarboxylic acid residues. For example, epoxy-functionalized compounds can be bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, brominated bisphenol A diglycidyl ether, brominated bisphenol F diglycidyl ether, brominated bisphenol S diglycidyl ether, epoxy phenolic varnish resin, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, hydrogenated bisphenol S diglycidyl ether, 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate, 2-(3 4-Epoxycyclohexyl-5,5-spiro-3,4-epoxy)cyclohexane-1,4-dioxane, bis(3,4-epoxycyclohexylmethyl) adipate, vinylcyclohexene oxide, limonene dioxide, bis(3,4-epoxy-6-methylcyclohexylmethyl) adipate, 3,4-epoxy-6-methylcyclohexyl-3',4'-epoxy-6'-methylcyclohexane carboxylate, methylene bis(3,4-epoxycyclohexane), dicyclopentadiene diepoxide ethylene glycol di(3,4-epoxycyclohexylmethyl) ether, ethylene bis(3,4-epoxycyclohexane carboxylate), epoxy hexahydrodioctyl phthalate, epoxy hexahydrodi-2-ethylhexyl phthalate, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, through aliphatic polyols (e.g., ethylene glycol diglycidyl ether). Polyether polyols obtained by adding one or more epoxides to glycols, propylene glycol, and glycerols, including polyglycidyl ethers of polyethers, diglycidyl esters of aliphatic long-chain dicarboxylic acids, monoglycidyl ethers of aliphatic higher alcohols, phenol, cresol, butylphenol, or monoglycidyl ethers of polyether alcohols obtained by adding epoxides to these compounds, glycidyl esters of higher fatty acids, epoxidized soybean oil, epoxidized butyl stearic acid, epoxidized octyl stearic acid, epoxidized linseed oil, epoxidized polybutadiene, etc.

[0055] The cationic polymerizable resin may include epoxy resin, preferably a multifunctional (preferably bifunctional) epoxy resin.

[0056] Epoxides may include alicyclic epoxides. Cationicly polymerizable resins may include bifunctional epoxy resins, such as bifunctional alicyclic epoxy resins. Bifunctional alicyclic epoxy resins may have a structure (V).

[0057] Structure (V)

[0058] Based on the total weight of the cationicly polymerizable resin (B), the cationicly polymerizable resin may contain at least 80% by weight, for example, at least 90% by weight, at least 95% by weight, at least 99% by weight, or even at least 99.9% by weight, of epoxy resin. The cationicly polymerizable resin may contain at least one epoxy resin, and is substantially composed of or constitutes thereof.

[0059] Suitable oxetanes capable of cationic polymerization include trimethylene oxide, 3,3-dimethyloxetane, 3,3-dichloromethyloxetane, 3-ethyl-3-phenoxymethyloxetane, and bis(3-ethyl-3-methyloxy)butane, 3-ethyl-3-oxetane, and methanol.

[0060] Suitable oxacyclopentanes capable of cationic polymerization include tetrahydrofuran and 2,3-dimethyltetrahydrofuran.

[0061] Suitable cyclic acetals capable of cationic polymerization include trioxane, 1,3-dioxolane, and 1,3,6-trioxanecyclooctane.

[0062] Suitable cyclic lactones capable of cationic polymerization include β-propiolactone and ε-caprolactone.

[0063] Suitable cyclothioethanes capable of cationic polymerization include ethylene sulfide, 1,2-propylene sulfide, and thio-representing chlorohydrins.

[0064] Suitable thioheterocyclic butanes capable of cationic polymerization include 3,3-dimethylthioheterocyclic butane.

[0065] Suitable spirocyclic orthoesters capable of cationic polymerization are compounds obtained through the reaction of epoxides and lactones.

[0066] Other suitable olefinically unsaturated compounds capable of cationic polymerization include vinyl ethers, such as ethylene glycol divinyl ether, triethylene glycol divinyl ether, and trimethylolpropane trivinyl ether; aliphatic vinyl monomers such as vinylcyclohexane; olefins such as isobutylene; dienes such as butadiene; vinyl alkyl ethers; vinyl aromatic monomers such as styrene and alkylstyrene; unsaturated polymers such as polybutadiene; derivatives of the above organic substances; etc., at least some of which can also be polymerized via a free radical mechanism.

[0067] The curable composition comprises D) a photoacid generator. The photoacid generator is sensitive to photochemical radiation in a second wavelength range. This second wavelength range may differ from the first wavelength range. In some embodiments, the second wavelength range may differ from but overlap with the first wavelength range. Typically, the photoacid generator is a salt, such as iodonium salts and sulfonium salts. When these salts are irradiated with photochemical radiation in the second wavelength range, they undergo homolytic bond breaking to form free radicals, which react with a proton donor to produce a Brønsted acid or Lewis acid. This acid initiates a polymerization reaction.

[0068] Photoacid generators (also known as cationic photoinitiators) may comprise onium salts, such as iodonium salts, sulfonium salts, pyridinium salts, alkoxypyridinium salts, phosphonium salts, oxonium salts, or diazonium salts. In embodiments, the photoacid generator may comprise sulfonium salts, iodonium salts, and / or other onium salts. Specifically, the photoacid generator may be an onium salt, such as a diaryliodonium salt and / or a triarylsulfonium salt. Such photoacid generators include sulfonium salts. Among the sulfonium salts are aromatic sulfonium salts. Specific examples include triphenylsulfonium salts, methyl diphenylsulfonium salts, dimethylphenylsulfonium salts, diphenylnaphthylsulfonium salts, and di(methoxy-naphthyl)methylsulfonium salts. Such aromatic sulfonium salts include those containing hexafluorophosphate ions (PF6). - ) or hexafluoroantimonate ion (SbF6) - Aromatic sulfonium salts as counterions. Specific examples include triphenylsulfonium hexafluorophosphate, methyl diphenyl-sulfonium hexafluorophosphate, dimethylphenyl-sulfonium hexafluorophosphate, diphenylnaphthyl-sulfonium hexafluorophosphate, di(methoxynaphthyl)methyl-sulfonium hexafluorophosphate, and triarylsulfonium hexafluoroantimonate (e.g., Speedcure 976).

[0069] Photoacid generators may comprise triarylsulfonium salts, such as (thioalkyldiphenyl-4,1-diyl)bis(diphenylsulfonium)bis(hexafluoroantimonate). Triarylsulfonium salts may comprise compounds of structures VI, VII, or both. Suitable triarylsulfonium-based photoacid generators are marketed under the trademark Speedcure. TM 976 was purchased from Sartomer Americas.

[0070] Structure (VI)

[0071] Structure (VII)

[0072] In the embodiments, based on the total weight of the photoacid generator, the photoacid generator may contain at least 80% by weight, at least 90% by weight, at least 95% by weight, at least 99% by weight, or even at least 99.9% by weight of an onium salt, such as a sulfonium salt. The photoacid generator may contain, consist of, or be substantially composed of at least one onium salt.

[0073] The photoacid generator can optionally be coupled to the photosensitive compound. Without being theoretically limited, certain radical photoinitiators can act as reducing agents when photoexcited to interact with the photoacid generator (e.g., iodonium salt) in a redox reaction. The resulting oxidized radical photoinitiator is then a cation, which can directly initiate cationic polymerization or interact with other components in the formulation to generate an active cation capable of initiating cationic photopolymerization. In embodiments, the photosensitive compound can be a radical photoinitiator sensitive to photochemical radiation in a first wavelength range. In embodiments, the radical photoinitiator can be a Norrish type I photoinitiator. Examples of such type I photoinitiators include, but are not limited to, Speedcure TPO, Speedcure BKL (Irgacure 651), and Speedcure BPO (BAPO). In other embodiments, the free radical photoinitiator can be selected from various Norrish type II photoinitiators, such as xanthones, thioxanthone, isopropylthioxanthone, chloropropoxythioxanthone, diethylthioxanthone, benzophenone, and acetophenone, or derivatives thereof, provided that the photosensitizer absorbs at the desired wavelength. In embodiments, the photoacid generator can be an iodonium salt, and the free radical photoinitiator can be selected from xanthones, thioxanthone, isopropylthioxanthone, chloropropoxythioxanthone, diethylthioxanthone, benzophenone, acetophenone, acylphosphine oxide, or derivatives thereof.

[0074] Suitable iodonium salts may be selected from bis(4-dodecylphenyl)iodonium hexafluoroantimonate (structure VIII); bis-(4-tert-butylphenyl)iodonium hexafluorophosphate (structure VIV); and 4-isopropyl-4'-methyldiphenyliodonium tetra(pentafluorophenyl)borate (structure X). Suitable commercially available bis(4-dodecylphenyl)iodonium hexafluoroantimonate of structure (VIII) may be branded under the name Speedcure. TM 937 was purchased from Sartomer Americas. Suitable commercially available bis-(4-tert-butylphenyl)-iodonium hexafluorophosphate with the structure (VIV) can be branded Speedcure. TM 938 was purchased from Sartomer Americas. Suitable commercially available 4-isopropyl-4'-methyldiphenyliodotetra(pentafluorophenyl)borate of structure (X) under the trademark Speedcure. TM Purchased from Sartomer Americas for item 939.

[0075] Structure VIII

[0076] Structure VI

[0077] Structure X

[0078] Photoacid generators are sensitive to photochemical radiation in the second wavelength range.

[0079] The second wavelength range may differ from the first wavelength range. Without being theoretically limited, using a second wavelength range different from the first wavelength range allows the operator to independently cure radical-polymerizable resins separately from cationic-polymerizable resins. In embodiments, the photoacid generator may be insensitive to the first wavelength range, or at least a portion thereof.

[0080] Photochemical radiation in the second wavelength range may include ultraviolet (UV) light, such as light in the UVB and UVC range, for example, light with wavelengths from 180 nm to 400 nm, such as 200 nm to 400 nm or 200 nm to 320 nm. In an embodiment, photochemical radiation in the second wavelength range may be generated by an H-bulb (mercury bulb).

[0081] Sensitivity to photochemical radiation in the second wavelength range means that when the photoacid generator is exposed to a second photochemical light source, the photoacid generator produces acid.

[0082] The photoacid generator may have a maximum absorption value within a second wavelength range. The photoacid generator may also have additional maximum absorption values ​​outside the second wavelength range. In addition to photochemical radiation within the second wavelength range, the photoacid generator may be sensitive to wavelengths outside those defined as the second wavelength range. In some cases, it is preferable that the photoacid generator is insensitive to wavelengths used as a first wavelength range for exciting free radical photoinitiators.

[0083] The curable composition comprises an E) polyol, preferably aliphatic. The polyol can be added to the curable composition to adjust its properties, such as flexibility, toughness, hydrolytic stability, and curing rate. Without being theoretically limited, it is believed that the polyol can act as a chain transfer agent, increasing the curing rate. The polyol can be one or more of polyether polyols, polyurethane polyols, polyacrylate polyols, polyester polyols, polycarbonate polyols, and polycaprolactone polyols. In particular, the polyol may comprise either a polycaprolactone polyol, a polyether polyol, or a polyester polyol, preferably a polycaprolactone polyol.

[0084] The polyol can be a diol, triol, or higher polyol, particularly a triol or more functional polyol. It should be understood that a diol is a polyol having two hydroxyl groups, and a triol is a polyol having three hydroxyl groups. Without being theoretically limited, it is believed that when the polyol is multifunctional (diol, triol, or higher polyol), chain transfer processes will produce crosslinks in the curable composition upon curing. In an embodiment, the polyol can be a triol.

[0085] The polyol can be a polycaprolactone polyol derived from the ring-opening of a lactone molecule. In an embodiment, the polycaprolactone polyol may have structure (XI).

[0086] Structure (XI)

[0087] Where R is

[0088] Where n is between 1 and 10.

[0089] Polyols may have viscosities (as measured by the methods described below) of less than 1000 cP at 25°C, such as less than 750 cP, less than 500 cP, less than 250 cP, less than 200 cP, less than 150 cP, 10 cP to 1000 cP, 10 cP to 500 cP, 10 cP to 250 cP, 10 cP to 200 cP, 50 cP to 1000 cP, 50 cP to 500 cP, 50 cP to 250 cP, 50 cP to 200 cP, 100 cP to 1000 cP, 100 cP to 500 cP, 100 cP to 250 cP, 100 cP to 200 cP, or any subset thereof.

[0090] The OH value of the polyol can be from 400 mg KOH / g to 800 mg KOH / g, for example, 500 KOH / g to 800 KOH / g, 400 KOH / g to 700 KOH / g, 400 KOH / g to 600 KOH / g, 500 KOH / g to 600 KOH / g, or any subset thereof, based on the total weight of the polyol.

[0091] Suitable polyols include Capa, purchased from Perstorp Polyols Inc. TM 3031.

[0092] In addition to the components described above, the curable compositions disclosed herein may also contain one or more additives. Such additives include, but are not limited to, antioxidants, UV absorbers, light stabilizers, foam inhibitors, flow agents or leveling agents, colorants, pigments, dispersants (wetting agents), slip additives, fillers (different from or other than inorganic nanoparticles), thixotropic agents, matting agents, accelerators, adhesion promoters (such as acidic adhesion promoters), tackifiers, thermoplastics and other types of polymers (different from or other than the block copolymers described above), waxes, or various other additives, including any additives conventionally used in coatings, sealants, adhesives, molding, or inks. In embodiments, the curable compositions may contain 0% to 20%, 0% to 10% by weight, 0% to 5% by weight, 0% to 1% by weight, 0% to 0.1% by weight, 0% to 0.01% by weight, or any subset thereof of additives.

[0093] Preferably, the curable composition of this disclosure comprises less than 5% by weight of a solvent based on the total weight of the curable composition. The solvent is well known to those skilled in the art and is used to dissolve the implemented components. Solvents include, for example, water, ethanol, isopropanol, butanol, propylene glycol methyl ether, ethyl acetate, butyl acetate, acetone, butanone, methyl isobutyl ketone, tetrahydrofuran, dioxane, N,N-dimethylformamide, dimethyl sulfoxide, acetonitrile, dichloromethane, chloroform, cyclohexane, benzene, toluene, xylene, etc.

[0094] In embodiments, the curable compositions of this disclosure may not include heat-melt-processable polymers, such as acrylic heat-melt polymers (also known as hot glues), which are typically 100% solid formulations based on thermoplastic polymers. Heat-melt-processable polymers are solid at room temperature and are “activated” when heated above their softening point. Once melted, the adhesive can be applied to a substrate in its liquefied or molten state. High molecular weight heat-melt-processable polymers are polymers with a molecular weight (Mn) of 50,000 g / mol to 500,000 g / mol, for example 150,000 g / mol to 200,000 g / mol; a molecular weight (Mw) of 100,000 g / mol to 1,000,000 g / mol, for example 400,000 g / mol to 700,000 g / mol; and a melting point of 80°C to 130°C. In an embodiment, the curable composition may contain less than 1% by weight, such as 0% to 1% by weight, 0% to 0.1% by weight, 0% to 0.01% by weight, or any subset thereof, of a heat-melt-processable polymer.

[0095] Based on the total weight of the curable composition, the curable composition may comprise 60 wt% to 90 wt% of a free radical polymerizable resin (A). Based on the total weight of the curable composition, the curable composition may preferably comprise 65 wt% to 87.5 wt%, more preferably 67.5 wt% to 86 wt% or any subset thereof of a free radical polymerizable resin (A). In embodiments, based on the total weight of the curable composition, the curable composition may comprise 60 wt% to 80 wt%, 60 wt% to 70 wt%, 65 wt% to 90 wt%, 70 wt% to 90 wt%, 75 wt% to 90 wt%, 80 wt% to 90 wt%, 85 wt% to 90 wt%, 70 wt% to 86 wt%, 75 wt% to 86 wt% or any subset thereof of a free radical polymerizable resin (A).

[0096] The curable composition may contain 1% to 60% by weight, preferably 2% to 30% by weight, more preferably 2% to 15% by weight, of at least one (meth)acrylate oligomer, based on the total weight of the curable composition. In embodiments, based on the total weight of the curable composition, the curable composition may contain 5% to 40% by weight, 8% to 30% by weight, 2% to 10% by weight, 4% to 10% by weight, 4% to 5% by weight, or any subset thereof, of at least one (meth)acrylate oligomer.

[0097] The curable composition may contain 20% to 89% by weight, preferably 40% to 87.5% by weight, more preferably 50% to 85% by weight, of at least one (meth)acrylate monomer, based on the total weight of the curable composition. In embodiments, based on the total weight of the curable composition, the curable composition may contain 30% to 89% by weight, 40% to 85% by weight, 60% to 85% by weight, 70% to 85% by weight, 20% to 75% by weight, 20% to 65% by weight, 20% to 55% by weight, 20% to 45% by weight, 20% to 35% by weight, 30% to 80% by weight, 35% to 75% by weight, 40% to 70% by weight, or any subset thereof, of at least one (meth)acrylate monomer.

[0098] In one embodiment, based on the total weight of the curable composition, the curable composition may contain 1% to 60% by weight, preferably 2% to 30% by weight, more preferably 2% to 15% by weight of at least one (meth)acrylate oligomer and 20% to 89% by weight, preferably 40% to 87.5% by weight, more preferably 50% to 85% by weight of at least one (meth)acrylate monomer. Specifically, based on the total weight of the curable composition, the curable composition may comprise at least one (meth)acrylate oligomer of 5% to 40% by weight, 8% to 30% by weight, 2% to 10% by weight, 4% to 10% by weight, 4% to 5% by weight or any subset thereof, and at least one (meth)acrylate monomer of 30% to 89% by weight, 40% to 85% by weight, 50% to 85% by weight, 60% to 85% by weight, 70% to 85% by weight, 20% to 75% by weight, 20% to 65% by weight, 20% to 55% by weight, 20% to 45% by weight, 20% to 35% by weight, 30% to 80% by weight, 35% to 75% by weight, 40% to 70% by weight or any subset thereof.

[0099] Based on the total weight of the curable composition, the curable composition may contain 2% to 30% by weight of a cationically polymerizable resin (B). In an embodiment, based on the total weight of the curable composition, the curable composition may preferably contain 4% to 27.5% by weight, more preferably 5% to 25% by weight or any subset thereof of a cationically polymerizable resin (B). In an embodiment, based on the total weight of the curable composition, the curable composition may contain 5% to 15% by weight, 5% to 10% by weight, 10% to 30% by weight, 15% to 30% by weight, 20% to 30% by weight, 25% to 30% by weight, 10% to 25% by weight, 15% to 20% by weight, 10% to 28% by weight, 15% to 25% by weight or any subset thereof of a cationically polymerizable resin (B).

[0100] The weight ratio of the free radical polymerizable resin (A) to the cationic polymerizable resin (B) is 32:1 to 2:1. The A:B ratio can be 19:1 to 7:3 or 11:1 to 4:1, more preferably 6:1 to 4:1, and especially 5:1.

[0101] Based on the total weight of the curable composition, the curable composition may contain 0.5 wt% to 8 wt%, preferably 1 wt% to 7 wt%, more preferably 3 wt% to 6 wt% of a free radical photoinitiator (C). In embodiments, based on the total weight of the curable composition, the curable composition may contain 1 wt% to 7 wt%, 2 wt% to 7 wt%, 3 wt% to 7 wt%, 4 wt% to 7 wt%, 5 wt% to 7 wt%, 0.5 wt% to 6 wt%, 0.5 wt% to 5 wt%, 0.5 wt% to 4 wt%, 0.5 wt% to 3 wt%, 0.5 wt% to 2 wt%, 1 wt% to 4 wt%, 2 wt% to 3 wt%, or any subset thereof of a free radical photoinitiator.

[0102] Based on the total weight of the cationicly polymerizable resin, the curable composition may contain 0.25 wt% to 5 wt%, preferably 0.5 wt% to 4 wt%, more preferably 1 wt% to 3 wt% of a photoacid generator (D). In embodiments, based on the total weight of the cationicly polymerizable resin, the curable composition may contain 0.25 wt% to 3 wt%, 0.25 wt% to 2.5 wt%, 1 wt% to 4 wt%, 2 wt% to 4 wt%, 0.5 wt% to 3 wt%, 1 wt% to 2.5 wt%, or any subset thereof of a photoacid generator (D). The concentration of the photoacid generator refers to the concentration of the photoacid generator compound itself and does not include any solvents or co-compounds that are not photoacid generators.

[0103] Based on the total weight of the curable composition, the curable composition may contain 0.5 wt% to 10 wt%, preferably 0.75 wt% to 7.5 wt%, more preferably 1 wt% to 5 wt% of polyol (E). In embodiments, based on the total weight of the curable composition, the curable composition may contain 0.5 wt% to 9 wt%, 0.5 wt% to 8 wt%, 0.5 wt% to 7.5 wt%, 0.5 wt% to 7 wt%, 0.5 wt% to 6 wt%, 0.5 wt% to 5 wt%, 1 wt% to 10 wt%, 1 wt% to 7.5 wt% or any subset thereof of polyol (E).

[0104] The curable composition may include:

[0105] 60% to 90% by weight, preferably 65% ​​to 87.5% by weight, more preferably 67.5% to 86% by weight of a free radical polymerizable resin;

[0106] 2% to 30% by weight, preferably 4% to 27.5% by weight, more preferably 5% to 25% by weight of a cationicly polymerizable resin;

[0107] 0.5% to 8% by weight, preferably 1% to 7% by weight, more preferably 3% to 6% by weight of free radical photoinitiator;

[0108] 0.25% to 5% by weight, preferably 0.5% to 4% by weight, more preferably 1% to 3% by weight of the photoacid generator; and

[0109] 0.5% to 10% by weight, preferably 0.75% to 7.5% by weight, more preferably 1% to 5% by weight of polyol, based on the total weight of the curable composition.

[0110] The curable composition may contain at least 80% by weight, such as at least 90% by weight, at least 95% by weight, at least 99% by weight, or even at least 99.9% by weight of the following substances, based on the total weight of the curable composition. The curable composition may contain, consist substantially of, or consist of the following substances: A) a free radical polymerizable resin; B) a cationic polymerizable resin; C) a free radical photoinitiator; D) a photoacid generator; and E) a polyol.

[0111] The curable composition can be partially cured, such as by exposure to photochemical radiation in a first wavelength range, thereby forming a partially cured reaction product. The partially cured reaction product can be a pressure-sensitive adhesive. A pressure-sensitive adhesive is one whose storage modulus (G') measured on a shear rheometer is less than 1 × 10⁻⁶. 5 Polymers of Pa.

[0112] The curable composition can be cured by exposure to photochemical radiation in a first wavelength range and a second wavelength range, thereby forming a radical-cured and cationic-cured composition. The dual-cured composition may have a 180-degree peel strength of at least 2 lb / in. In embodiments, the dual-cured composition may have a 180-degree peel strength of at least 3 lb / in, at least 4 lb / in, at least 5 lb / in, or at least 6 lb / in, for example, as measured according to ASTM D3330.

[0113] The curable composition can be cured by exposure to photochemical radiation in a first wavelength range, photochemical radiation in a second wavelength range, and thermal shock to form a cured composition. The cured composition may have a 180-degree peel strength of at least 2 lb / in. In embodiments, the cured composition may have a 180-degree peel strength of at least 3 lb / in, at least 4 lb / in, at least 5 lb / in, or at least 6 lb / in, for example, as measured according to ASTM D3330.

[0114] The dual-cured composition may have a static shear strength of at least 500 minutes. In embodiments, the dual-cured composition may have a static shear strength of at least 750 minutes, at least 1000 minutes, at least 1500 minutes, at least 2000 minutes, at least 5000 minutes, or at least 10000 minutes, for example, measured according to ASTM D3654 at a temperature of 27°C under a 500 g load.

[0115] The cured composition may have a static shear strength of at least 500 minutes. In embodiments, the cured composition may have a static shear strength of at least 750 minutes, at least 1000 minutes, at least 1500 minutes, at least 2000 minutes, at least 5000 minutes, or at least 10000 minutes, for example, measured according to ASTM D3654 at a temperature of 27°C under a 500 g load.

[0116] Methods for curing a curable composition may include exposing the curable composition to photochemical radiation in a first wavelength range to produce a composition that is at least partially free-radical cured; and exposing the free-radical cured composition to photochemical radiation in a second wavelength range to produce a dual-cured composition.

[0117] In some embodiments, such as when the photoacid generator is an iodonium salt, the curable composition can be cured by exposing it to photochemical radiation within a first wavelength range, resulting in a dual-cured composition. In such embodiments, the photochemical radiation within the first wavelength range activates both the radical photoinitiator and the photoacid generator. If the first light source is a long wavelength (beyond the direct absorption of the photoacid generator as described above), the iodonium salt can be activated by the "redox sensitization" of the iodonium salt by free radicals generated by the radical photoinitiator. Typically, sulfonium salts are believed to be less useful in such systems because they are weaker oxidizing agents than iodonium salts. In embodiments, the composition can be cured in one step using a radical photoinitiator and a sulfonium or iodonium salt photoacid generator via a short-wavelength light source. In these single-step embodiments, the short-wavelength light can activate both the radical and cationic photoinitiator, regardless of whether the cationic initiator is a sulfonium salt or an iodonium salt.

[0118] The curable composition can be exposed to photochemical radiation in a first wavelength range, wherein the total dose of the first photochemical light is 100 mJ / cm. 2 Up to 2000mJ / cm 2 Such as 250mJ / cm 2 Up to 2000mJ / cm 2 500mJ / cm 2 Up to 2000mJ / cm 2 or any subset thereof.

[0119] The curable composition can be exposed to photochemical radiation in a first wavelength range at room temperature (such as 20°C to 30°C).

[0120] The free radical-cured composition can be exposed to photochemical radiation in a second wavelength range, wherein the total dose of the second photochemical light is 200 mJ / cm². 2 Up to 5000mJ / cm 2 For example, 500mJ / cm 2 Up to 5000mJ / cm 2 1000mJ / cm 2 Up to 5000mJ / cm 2 1500mJ / cm 2 Up to 5000mJ / cm 2 , or any subset thereof.

[0121] The free radical cured composition can be exposed to photochemical radiation in the second wavelength range at room temperature (such as 20°C to 30°C).

[0122] The dual-curing composition may be further exposed to a temperature of at least 50°C, for example, 50°C to 100°C, preferably 50°C to 80°C, for at least 30 minutes, for example, 15 minutes to 4 hours, 15 minutes to 3 hours, 15 minutes to 2 hours, 30 minutes to 4 hours, 30 minutes to 3 hours, 30 minutes to 2 hours, or any subset thereof, to produce a cured pressure-sensitive adhesive.

[0123] Methods of using a curable composition may include applying the curable composition to a first substrate; exposing the curable composition to photochemical radiation in a first wavelength range to produce a composition that is at least partially free-radical cured; adhering the free-radical cured composition to a second surface; and exposing the free-radical cured composition to photochemical radiation in a second wavelength range before or after the adhesion step to produce a double-cured composition.

[0124] Methods of using a curable composition may include applying the curable composition to a first substrate; exposing the curable composition to photochemical radiation within the first wavelength range to generate a radical-cured composition that is at least partially cured; and adhering the radical-cured composition to a second surface. The radical photoinitiator may be capable of sensitizing a photoacid generator, and the photoacid generator may be an iodonium salt.

[0125] The free radical photoinitiator can be selected from xanthones, thioxanone, isopropylthioxanone, chloropropoxythioxanone, diethylthioxanone, benzophenone, acetophenone and phosphine oxide (e.g., acylphosphine oxide) or derivatives thereof.

[0126] Iodonium salts may be selected from bis(4-dodecylphenyl)iodonium hexafluoroantimonate; bis-(4-tert-butylphenyl)-iodonium hexafluorophosphate; and 4-isopropyl-4'-methyldiphenyliodonium tetra(pentafluorophenyl)borate.

[0127] Measurement methods

[0128] 180 ° Peel strength

[0129] 180 ° Peel strength was determined according to the standard test method ASTM D3330. As described below, 180... ° The peel strength method differs from ASTM D3330 in that the samples of this invention are conditioned in a constant temperature and humidity chamber for 24 hours, rather than being tested within one minute of preparation as specified in the ASTM standard.

[0130] Specifically, the sample was cut into 1-inch strips and laminated twice onto a stainless steel plate using a Chem Instruments down-rolling instrument, which applies a force of 4.5 pounds at a rate of 10 mm / s according to ASTM D3330. To prepare 180... ° For the peel test, the sample was conditioned in a constant temperature and humidity chamber for 24 hours. At 180°C... ° During the peel test, the sample was stretched at 12 in / min using an Instron machine (model 5543) with a 100 N load sensor, and its peel strength averaged from 1–3 inches of elongation.

[0131] Results are reported in pounds per inch (lb / in) for belt width.

[0132] Static shear resistance

[0133] Static shear resistance was determined according to ASTM D3654. As described below, the static shear method differs from ASTM D3654 in that the samples of this invention are conditioned in a constant temperature and humidity chamber for 24 hours, instead of being tested within one minute of preparation as specified in the ASTM standard. A further difference is the use of a 1” × 1” square adhesive and a weight of 500 g.

[0134] Specifically, samples were prepared in the same manner as the 180° peel strength samples. A 1” × 1” square inch sheet of adhesive was vertically mounted onto the ChemInstruments EZ Shear, and a standard 500 g mass was attached to the free end of the tape. The failure time (the time it took for the tape to completely separate from the panel) was then determined.

[0135] Viscosity

[0136] Viscosity was measured at room temperature or 60°C using a Brookfield DV-III+ viscometer with an SC-27 rotor (if the viscosity was high enough that the viscometer would not work at room temperature). Each sample was measured at a certain number of revolutions per minute (rpm) required to achieve 50% of the torque range. After the temperature and sample had stabilized (typically after 10 minutes), the viscosity was measured in centipoises (cP).

[0137] aspect

[0138] 1. According to a first aspect, the curable composition may comprise A) a free radical polymerizable resin comprising at least one (meth)acrylate monomer, at least one (meth)acrylate oligomer, or both (preferably both); B) a cationic polymerizable resin; C) a free radical photoinitiator; D) a photoacid generator; and E) a polyol; wherein the weight ratio of A:B is from 32:1 to 2:1.

[0139] 2. According to the second aspect, in conjunction with the first aspect, the curable composition may comprise (meth)acrylate oligomers.

[0140] 3. According to the third aspect, in conjunction with any one of aspects 1-2, based on the total weight of the curable composition, the curable composition may contain 1% to 60% by weight, preferably 2% to 30% by weight, more preferably 2% to 15% by weight of at least one (meth)acrylate oligomer.

[0141] 4. According to the fourth aspect, in conjunction with any one of aspects 1-3, the free radical polymerizable resin may contain at least one (meth)acrylate monomer.

[0142] 5. According to the fifth aspect, in conjunction with any one of aspects 1-4, the at least one (meth)acrylate monomer, the at least one (meth)acrylate oligomer, or both may be monofunctional.

[0143] 6. According to the sixth aspect, in conjunction with any one of aspects 1-5, the at least one (meth)acrylate monomer may be selected from isobornyl (meth)acrylate (preferably IBOA), alkoxylated tetrahydrofurfuryl (meth)acrylate (preferably THFA), or both.

[0144] 7. According to the seventh aspect, in conjunction with any one of aspects 1-6, based on the total weight of the curable composition, the curable composition may contain 20% to 89% by weight, preferably 40% to 87.5% by weight, more preferably 50% to 85% by weight of at least one (meth)acrylate monomer.

[0145] 8. According to the eighth aspect, in conjunction with any one of aspects 1-7, the polyol may be a polycaprolactone polyol, a polyether polyol or a polyester polyol, preferably a polycaprolactone polyol.

[0146] 9. According to the ninth aspect, in conjunction with any one of aspects 1-8, based on the total weight of the curable composition, the curable composition may contain 60% to 90% by weight, preferably 65% ​​to 87.5% by weight, more preferably 67.5% to 86% by weight of a free radical polymerizable resin.

[0147] 10. According to the tenth aspect, in conjunction with any one of aspects 1-9, the cationicly polymerizable resin may include an epoxy resin, preferably a multifunctional (preferably bifunctional) epoxy resin.

[0148] 11. According to the eleventh aspect, in conjunction with any one of aspects 1-10, the epoxide may include an alicyclic epoxide.

[0149] 12. According to the twelfth aspect, in conjunction with any one of aspects 1-11, the cationicly polymerizable resin may include one or more of glycidyl ether, vinyl ether, or oxetane.

[0150] 13. According to the thirteenth aspect, in conjunction with any one of aspects 1-12, based on the total weight of the curable composition, the curable composition may contain 2% to 30% by weight, preferably 4% to 27.5% by weight, more preferably 5% to 25% by weight of a cationicly polymerizable resin.

[0151] 14. According to aspect fourteen, in conjunction with any one of aspects 1-13, the free radical photoinitiator can be sensitive to photochemical radiation in a first wavelength range of 365 nm to 450 nm.

[0152] 15. According to aspect fifteen, in conjunction with any one of aspects 1-14, the free radical photoinitiator may include a structure having Compounds.

[0153] 16. In accordance with aspect sixteen, in conjunction with aspect 15, the free radical photoinitiator may further comprise having a structure Compounds.

[0154] 17. According to the seventeenth aspect, in conjunction with any one of aspects 1-16, based on the total weight of the curable composition, the curable composition may contain 0.5% to 8% by weight, preferably 1% to 7% by weight, more preferably 3% to 6% by weight of a free radical photoinitiator.

[0155] 18. According to the eighteenth aspect, in conjunction with any one of aspects 1-17, the photoacid generator can be sensitive to photochemical radiation in the second wavelength range of 200 nm to 400 nm, preferably 200 nm to 320 nm.

[0156] 19. According to the nineteenth aspect, in conjunction with any one of aspects 1-18, the photoacid generating agent may be an onium salt.

[0157] 20. In accordance with aspect 20, in conjunction with aspect 19, the onium salt may be an iodonium salt, such as a diaryliodonium salt and / or a triarylsulfonium salt.

[0158] 21. According to aspect 21, in conjunction with aspect 20, sulfite salts may contain structures ,structure Compounds or both.

[0159] 22. According to the twenty-second aspect, in conjunction with any one of aspects 1-21, based on the total weight of the curable composition, the curable composition may contain 0.25% to 5% by weight, preferably 0.5% to 4% by weight, more preferably 1% to 3% by weight of a photoacid generator.

[0160] 23. According to aspect 23, in conjunction with any one of aspects 1-22, the polyol may be a polycaprolactone polyol.

[0161] 24. According to aspect 24, in conjunction with any one of aspects 1-23, the polyol may be a triol or a polyol with higher functionality.

[0162] 25. In accordance with aspect 25, in conjunction with aspect 23, polycaprolactone polyols may include structures compounds

[0163] in , where n is from 1 to 10.

[0164] 26. According to the twenty-sixth aspect, in conjunction with any one of aspects 1-25, based on the total weight of the curable composition, the curable composition may contain 0.5% to 10% by weight, preferably 0.75% to 7.5% by weight, more preferably 1% to 5% by weight of a polyol.

[0165] 27. According to aspect 27, in conjunction with any one of aspects 1-26, the weight ratio of A:B can be from 19:1 to 7:3.

[0166] 28. According to aspect 28, in conjunction with any one of aspects 1-27, the weight ratio of A:B can be from 11:1 to 4:1, more preferably from 6:1 to 4:1, and particularly 5:1.

[0167] 29. According to aspect 29, in conjunction with any of aspects 1-28, when cured, the 180-degree peel strength of the curable composition, as measured according to ASTM D3330, may be at least 2 pounds (lb / in), preferably 3 lb / in, more preferably 4 lb / in.

[0168] 30. According to the thirtieth aspect, in conjunction with any one of aspects 1-29, when cured, the curable composition may have a static shear strength of at least 500 minutes, as measured according to ASTM D3654 at a temperature of 27°C under a 500 g load.

[0169] 31. According to aspect thirty-one, in conjunction with any one of aspects 1-30, polyols may be aliphatic.

[0170] 32. According to aspect thirty-two, in conjunction with any one of aspects 1-31, a method for curing a curable composition may include: exposing the curable composition to photochemical radiation in a first wavelength range to produce a composition that is at least partially free radical cured; and exposing the free radical cured composition to photochemical radiation in a second wavelength range to produce a double-cured composition.

[0171] 33. According to aspect thirty-three, in conjunction with any one of aspects 1-31, a method for curing a curable composition may include: exposing the curable composition to photochemical radiation in a first wavelength range, thereby producing a double-cured composition.

[0172] 34. According to aspect thirty-four, in conjunction with aspects 1-33, the photoacid generating agent may include iodonium salt.

[0173] 35. According to the thirty-fifth aspect, in conjunction with any one of aspects 32 to 34, the method may further include exposing the double-cured composition to a temperature of 50°C to 100°C, preferably 50°C to 80°C, for 15 minutes to 4 hours, preferably 15 minutes to 3 hours, more preferably 30 minutes to 2 hours.

[0174] 36. According to the thirty-sixth aspect, in conjunction with any one of aspects 32-35, the first wavelength range may be from 365 nm to 450 nm.

[0175] 37. According to aspect thirty-seven, in conjunction with any one of aspects 32 to 36, the second wavelength range may be from 200 nm to 400 nm, preferably from 200 nm to 320 nm.

[0176] 38. According to aspect thirty-eight, in conjunction with any one of aspects 32-37, the curable composition may be exposed to photochemical radiation in a first wavelength range, wherein the total first photochemical radiation dose is 100 mJ / cm². 2 Up to 2000mJ / cm2 Optimal 250mJ / cm 2 Up to 2000mJ / cm 2 More preferably 500mJ / cm 2 Up to 2000mJ / cm 2 .

[0177] 39. According to aspect thirty-nine, in conjunction with any one of aspects 32-38, the curable composition may be exposed to photochemical radiation in a first wavelength range at a temperature of 20°C to 30°C.

[0178] 40. According to aspect 40, in conjunction with any one of aspects 32-39, the free radical-cured composition may be exposed to photochemical radiation in a second wavelength range, wherein the total second photochemical radiation dose is 200 mJ / cm². 2 Up to 5000mJ / cm 2 500mJ / cm 2 Up to 5000mJ / cm 2 More preferably 1,000 mJ / cm 2 Up to 5000mJ / cm 2 Even better, 1500mJ / cm 2 Up to 5000mJ / cm 2 .

[0179] 41. According to aspect 41, in conjunction with any one of aspects 32-40, the free radical cured composition may be exposed to photochemical radiation in the second wavelength range at a temperature of 20°C to 30°C.

[0180] 42. According to aspect 42, in conjunction with any one of aspects 1-31, a method of using the curable composition may comprise: applying the curable composition to a first substrate; exposing the curable composition to photochemical radiation in a first wavelength range to produce a free radical-cured composition that is at least partially cured; adhering the free radical-cured composition to a second surface; and exposing the free radical-cured composition to photochemical radiation in a second wavelength range before or after the adhesion step to produce a double-cured composition.

[0181] 43. According to aspect 43, in conjunction with aspect 42, the method may further include exposing the dual-cured composition to a temperature of 50°C to 80°C for 30 minutes to 2 hours.

[0182] 44. According to aspect 44, in conjunction with any one of aspects 1-31, a method of using the curable composition may comprise: applying the curable composition to a first substrate; exposing the curable composition to photochemical radiation in the first wavelength range to generate at least partially cured free radical-cured composition; and adhering the free radical-cured composition to a second surface, wherein: the free radical photoinitiator is capable of sensitizing a photoacid generator; and the photoacid generator is an iodonium salt.

[0183] 45. According to aspect 45, in conjunction with aspect 44, the free radical photoinitiator may be selected from xanthones, thioxanthone, isopropylthioxanthone, chloropropoxythioxanthone, diethylthioxanthone, benzophenone and acetophenone, or derivatives thereof.

[0184] 46. ​​According to aspect 46, in conjunction with aspect 44 or 45, the iodonium salt may be selected from bis(4-dodecylphenyl)iodonium hexafluoroantimonate; bis-(4-tert-butylphenyl)-iodonium hexafluorophosphate; 4-isopropyl-4'-methyldiphenyliodonium tetra(pentafluorophenyl)borate.

[0185] 47. According to aspect 47, in conjunction with any one of aspects 1 to 31, the free radical photoinitiator may be sensitive to photochemical radiation in a first wavelength range.

[0186] 48. According to aspect 48, in conjunction with aspect 47, the first wavelength range may be 365 nm to 450 nm.

[0187] 49. According to aspect 49, in conjunction with any one of aspects 1 to 31, 47 or 48, the photoacid generator may be sensitive to photochemical radiation in the second wavelength range.

[0188] 50. According to the fiftieth aspect, in conjunction with aspect 49, the second wavelength range may be from 200 nm to 400 nm, preferably from 200 nm to 320 nm.

[0189] 51. According to aspect 51, in conjunction with aspect 49, the first wavelength range and the second wavelength range may overlap.

[0190] 52. According to aspect 52, in conjunction with any one of aspects 1 to 51, the curable composition may comprise 60% to 90% by weight, preferably 65% ​​to 87.5% by weight, more preferably 67.5% to 86% by weight of a free radical polymerizable resin; 2% to 30% by weight, preferably 4% to 27.5% by weight, more preferably 5% to 25% by weight of a cationic polymerizable resin; 0.5% to 8% by weight, preferably 1% to 7% by weight, more preferably 3% to 6% by weight of a free radical photoinitiator; 0.25% to 5% by weight, preferably 0.5% to 4% by weight, more preferably 1% to 3% by weight of a photoacid generator; and 0.5% to 10% by weight, preferably 0.75% to 7.5% by weight, more preferably 1% to 5% by weight of a polyol.

[0191] Example

[0192] The following examples are provided to illustrate the implementation schemes described in this disclosure and are not intended to limit the scope of this disclosure or its appended claims.

[0193] In the case of the H-bulb mentioned in the embodiments, a 300-watt (W) / inch mercury vapor emission bulb manufactured by Fusion UV is used.

[0194] Sulfonium salt photoacid-producing agent

[0195] The following were combined: urethane acrylate oligomer (CN9018, obtained from Sartomer Americas, 5 wt%), isoborneol acrylate (SR506A, obtained from Sartomer Americas, 45 wt%), alkoxylated tetrahydrofurfuryl acrylate (SR611, obtained from Sartomer Americas, 45 wt%), and a free radical photoinitiator (Speedcure). TM 4265, obtained from Sartomer Americas, 5% by weight, was combined to form a prepolymer blend. Specifically, the components were added to a one-gallon paint can and mixed with a top-mounted mixer for 3 hours until homogeneous. The prepolymer blend was then added to a polypropylene cup, and different proportions of cationically polymerizable resin (Uvicure from Sartomer Americas) were added. TM S128), polyols (from Perstorp Polyols Inc. Capa) TM 3031) and sulfonium photoacid generator (from Sartomer Americas' Speedcure) TM976) Add to the prepolymer blend in the proportions shown in Table 1. Mix the components at 2000 RPM for 2 minutes until homogeneous using a Flacktek® DAC 400.2 VAC high-speed mixer.

[0196] Table 1

[0197]

[0198] The goal was to test the 180° peel strength and static shear strength of each of three curing methods using 395nm LED, 395nm LED + H-bulb, and 395nm LED + H-bulb + thermal shock (60°C for 60 minutes). To compare the peel strength of samples (CE-A, CE-B, EX-1, EX-2) under each condition, each sample (CE-A, CE-B, EX-1, EX-2) was pipetted onto a clean sheet of untreated PET, which was adhered to an aluminum plate with 50 μm thick tape. Using the tape as a guide, the coating was applied to the PET substrate using a zero-mil scraper. The coating was then passed through a Phoseon 395nm LED (50 fpm, 3 passes) to cure the free-radical polymerizable resin, and the sample was removed for testing. Next, the remaining samples were passed through a Fusion H-bulb curing unit (16 fpm, 3 passes) and the samples were removed for testing. Then, the remaining sample was exposed to a temperature of 60°C for 60 minutes.

[0199] For each sample, once cured, the release liner is manually rolled onto the sample for easier management. The thickness of each sample is recorded in multiple areas to obtain an average thickness. The sample is then cut into 1-inch diameter strips and laminated twice onto a stainless steel plate using a Chem Instruments roll-down instrument, which applies a force of 4.5 pounds at a rate of 10 mm / s according to ASTM D3330. To prepare 180... ° For the peel test, each sample was conditioned for 24 hours in a chamber with constant temperature (23°C ± 2°C) and humidity (50%RH ± 10%RH). At 180°C... ° During the peel test, the sample was pulled at 12 in / min using an Instron machine (Model 5543) equipped with a 100 N force sensor, and its peel strength was obtained by averaging the elongation from 1 to 3 inches. The results are shown in Table 2.

[0200] Table 2

[0201]

[0202] After LED curing, EX-1 and EX-2 showed peel strengths between 0.8 lb / in and 1.2 lb / in. After LED + H bulb curing, which causes the remaining portion of the free-radically polymerizable resin to cure and initiates curing of the cationically polymerizable resin, the peel strength of both EX-1 and EX-2 increased to greater than 4.0 lb / in. Without wishing to be bound by theory, it is believed that this is due to the photoacid generator generating a photoacid and curing the epoxy portion of the sample. It is believed that this acid-curing propagation will continue to occur over time, as can be seen from the results of thermal shock. After thermal shock, the peel strength of both EX-1 and EX-2 increased to approximately 7 lb / in, while the control samples remained between 2 - 4 lb / in as they do not have epoxies.

[0203] Static shear is a measure of the cohesive strength of UV-PSA formulations. Static shear allows the measurement of the ability of an adhesive tape to remain bonded under a constant load applied parallel to the surface.

[0204] The static shear procedure is similar to ASTM D3654. Samples were prepared in a manner similar to the 180 ° peel strength samples shown above. However, for the static shear test, after conditioning in a constant temperature chamber, a 1" x 1" square inch of the adhesive was mounted vertically onto a ChemInstruments EZ Shear and a standard 500 g mass was attached to the free end of the tape. The failure time (the time when the tape is completely separated from the panel) was determined. The results are given in Table 3.

[0205] Table 3

[0206]

[0207] After LED curing, EX-1 and EX-2 showed static shear values between 3 minutes and 34 minutes. After LED + H bulb curing, the static shear of EX-1 and EX-2 increased to 9 minutes and 231 minutes, respectively. Without wishing to be bound by theory, it is believed that this is due to the photoacid generator generating a photoacid and curing the epoxy portion of the sample. It is believed that this acid-curing propagation will continue to occur over time, as can be seen from the results of thermal shock (TB). After thermal shock, the static shear of EX-1 and EX-2 increased to 2,052 min and 10,080 min, while the control samples (which do not contain epoxy components) remained between 65 min and 200 min.

[0208] Iodonium salt photoacid-producing agent

[0209] The following were combined: urethane acrylate oligomer (CN9018, obtained from Sartomer Americas, 5 wt%), isoborneol acrylate (SR506A, obtained from Sartomer Americas, 45 wt%), alkoxylated tetrahydrofurfuryl acrylate (SR611, obtained from Sartomer Americas, 45 wt%), and a free radical photoinitiator (Speedcure). TM 4265, obtained from Sartomer Americas, 5% by weight, was combined to form a prepolymer blend. Specifically, the components were added to a one-gallon paint can and mixed with a top-mounted mixer for 3 hours until homogeneous. The prepolymer blend was then added to a polypropylene cup, and different proportions of cationically polymerizable resin (Uvicure from Sartomer Americas) were added. TM S128), polyols (from Perstorp Polyols Inc. Capa) TM 3031) and iodonium salt photoacid generator (from Sartomer Americas' Speedcure) TM 937) Add to the prepolymer blend in the proportions shown in Table 2. Mix the components at 2000 RPM for 2 minutes until homogeneous using a Flacktek® DAC 400.2 VAC high-speed mixer.

[0210] Table 4

[0211]

[0212] The aim was to test the 180° peel strength and static shear strength of each of four conditioning methods (395nm LED, 395nm LED + 2-day curing time, 395nm LED + 3-day curing time, and 395nm LED + 7-day curing time). To compare the peel strength of samples (CE-C, CE-D, EX-3) under each condition, each sample (CE-C, CE-D, EX-3) was pipetted onto a clean sheet of untreated PET, which was adhered to an aluminum panel with 50 μm thick adhesive tape. Using the tape as a guide, the coating was applied to the PET substrate using a zero-dense scraper. The coating was passed through a Phoseon 395nm LED (50 fpm, 3 passes) to cure the free radical polymerizable resin and begin curing the cationic polymerizable resin. The samples were then removed for conditioning and testing.

[0213] For each sample, once cured, the release liner was manually wound onto the sample to allow for easier handling. The thickness of each sample was recorded in multiple areas to obtain an average thickness. The samples were then cut into 1-inch diameter strips and laminated onto stainless steel plates twice using a Chem Instruments roll down instrument that applied a force of 4.5 pounds at a rate of 10 mm / sec according to ASTM D3330. To prepare for the 180 ° peel test, each sample was conditioned in a room at a constant temperature (23°C + / - 2°C) and humidity (50% RH + / - 10% RH) for 24 hours, 2 days, 3 days, or 7 days. During the 180 ° peel test, the sample was pulled at 12 in / min using an Instron machine (Model 5543) with a 100 N load cell, and its peel strength was averaged from the elongation from 1 - to 3-inches. The results are shown in Table 5.

[0214] Table 5

[0215]

[0216] After LED curing, EX-3 showed a peel strength of 1.15 pounds force per inch (lb / in). After LED + 2 days, the peel strength of EX-3 remained constant at 1.00 lb / in. After LED + 3 days, the peel strength of EX-3 increased to 3.26 lb / in. After LED + 7 days, the peel strength of EX-3 continued to increase to 5.36 lb / in. It is believed that the increased 180 ° peel strength is due to the Speedcure TPO sensitized photoacid generator (Speedcure 937), which initiates the curing of the epoxy portion of the sample. The control sample CE-C (which does not contain an epoxide) remained between 3 - 4 lb / in. The control sample CE-D (which does not contain a photoacid generator) remained between 0 - 1 lb / in.

[0217] The static shear procedure was similar to ASTM D3654. Samples were prepared in a manner similar to the 180 ° peel strength samples shown above. However, for the static shear test, after conditioning in a constant temperature room, a 1" x 1" square of the adhesive was mounted vertically onto a ChemInstruments EZ Shear, and a standard 500 g mass was attached to the free end of the tape. The failure time (the time when the tape is completely separated from the panel) was determined. The results are given in Table 6.

[0218] Table 6

[0219]

[0220] After LED curing, EX-3 showed a static shear of 0.9 min. After LED+2 days, the static shear of EX-3 increased to 5.2 min. After LED+3 days, the static shear of EX-3 remained constant at 3.4 min. After LED+7 days, the static shear of EX-3 continued to increase to 46.5 min. It is believed that the increased static shear is due to the Speedcure TPO sensitized photoacid generator (Speedcure 937), which initiates the curing of the epoxy portion of the sample. Control sample CE-C (which does not contain epoxy compounds) maintained a static shear of 3–5 min. Control sample CE-D (which does not contain photoacid generator) maintained a static shear of 0–2 min.

[0221] It should be understood that any two quantitative values ​​assigned to a property can constitute a range of that property, and all combinations of ranges formed by all said quantitative values ​​of a given property are considered in this disclosure.

[0222] While specific embodiments of the invention have been illustrated and described, it will be apparent to those skilled in the art that numerous other changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, it is intended that all such changes and modifications falling within the scope of the invention be covered by the appended claims.

Claims

1. A curable composition comprising: A) A free radical polymerizable resin, wherein the free radical polymerizable resin comprises at least one (meth)acrylate monomer, at least one (meth)acrylate oligomer, or both. B) Resins that can be cationically polymerized; C) Free radical photoinitiators; D) Photoacid generators; and E) Polyols; The weight ratio of A to B is 32:1 to 2:

1.

2. The curable composition according to claim 1, wherein the at least one (meth)acrylate monomer is monofunctional.

3. The curable composition according to any one of claims 1 or 2, wherein the at least one (meth)acrylate monomer is selected from isobornyl (meth)acrylate (preferably IBOA), tetrahydrofurfuryl alkoxylated (meth)acrylate (preferably THFA), or both.

4. The curable composition according to any one of claims 1 to 3, wherein the free radical polymerizable resin comprises at least one (meth)acrylate monomer and at least one (meth)acrylate oligomer.

5. The curable composition according to any one of claims 1 to 4, wherein the cationicly polymerizable resin comprises an epoxy resin, preferably a multifunctional (preferably bifunctional) epoxy resin.

6. The curable composition according to any one of claims 1 to 5, wherein the photoacid generator is an onium salt, such as a triarylsulfonium salt.

7. The curable composition according to any one of claims 1 to 6, wherein the polyol is aliphatic.

8. The curable composition according to any one of claims 1 to 7, wherein the polyol is a polycaprolactone polyol, a polyether polyol or a polyester polyol, preferably a polycaprolactone polyol.

9. The curable composition according to any one of claims 1 to 8, wherein the polyol is a polycaprolactone polyol.

10. The curable composition according to any one of claims 1-9, wherein the polyol is a triol or a higher functional polyol.

11. The curable composition of any one of claims 1 to 10, wherein the polyol comprises a polycaprolactone polyol, the polycaprolactone polyol comprising a compound with the following structure ， in Where n is between 1 and 10.

12. The curable composition according to any one of claims 1 to 11, wherein: The weight ratio of A:B is 19:1 to 7:3, preferably 11:1 to 4:1, more preferably 6:1 to 4:1, and especially 5:

1.

13. The curable composition according to any one of claims 1 to 12, wherein the curable composition comprises: 60% to 90% by weight, preferably 65% ​​to 87.5% by weight, more preferably 67.5% to 86% by weight of a free radical polymerizable resin; 2% to 30% by weight, preferably 4% to 27.5% by weight, more preferably 5% to 25% by weight of a cationicly polymerizable resin; 0.5% to 8% by weight, preferably 1% to 7% by weight, more preferably 3% to 6% by weight of free radical photoinitiator; 0.25% to 5% by weight, preferably 0.5% to 4% by weight, more preferably 1% to 3% by weight of the photoacid generator; and 0.5% to 10% by weight, preferably 0.75% to 7.5% by weight, more preferably 1% to 5% by weight of polyol, based on the total weight of the curable composition.

14. The curable composition according to any one of claims 1 to 13, wherein the free radical photoinitiator is sensitive to photochemical radiation in a first wavelength range, and the photoacid generator is sensitive to photochemical radiation in a second wavelength range.

15. A method of using a curable composition according to any one of claims 1-14, the method comprising: The curable composition is applied to a first substrate; The curable composition is exposed to photochemical radiation in a first wavelength range to produce a free radical-cured composition that is at least partially cured; The free radical-cured composition is adhered to the second surface; and Before or after the adhesion step, the free radical-cured composition is exposed to photochemical radiation in a second wavelength range to produce a double-cured composition.

16. The method of claim 15, further comprising exposing the dual-cured composition to 50°C. o C to 80 o The temperature C is maintained for 30 minutes to 2 hours.

17. A method of using a curable composition according to any one of claims 1-14, the method comprising: The curable composition is applied to a first substrate; The curable composition is exposed to photochemical radiation in a first wavelength range to produce a free radical-cured composition that is at least partially cured; and The free radical-cured composition is adhered to the second surface, wherein: The free radical photoinitiator can sensitize the photoacid generator; and The photoacid generator is iodonium salt.

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