Radiation-curable epoxy-based compositions

Abstract

This invention provides radiation-curable epoxy-based compositions, cured products thereof, articles prepared therefrom, and uses thereof, said radiation-curable epoxy-based compositions comprising (a) an epoxy component and at least one cationic photoinitiator, said epoxy component comprising (a-1) at least one alicyclic epoxy compound of formula (I): L-(A). n The present invention also provides the use of the alicyclic epoxy compound of formula (I) in a radiation-curable epoxy-based composition for improving the storage modulus stability of the cured product of the epoxy-based composition, and preferably simultaneously improving water resistance. The cured product of the radiation-curable epoxy-based composition provided herein exhibits low storage modulus loss under high humidity conditions, and preferably also low water absorption.

Description

Technical Field

[0001] This invention relates to radiation-curable epoxy-based compositions, their cured products, their uses, and articles prepared therefrom, said compositions comprising an epoxy component, at least one cationic photoinitiator, and one or more optional additives, said epoxy component comprising a specific alicyclic epoxy compound. The invention also relates to the use of the specific alicyclic epoxy compound in radiation-curable epoxy-based compositions for improving the storage modulus stability of the cured product of said epoxy-based composition, preferably simultaneously improving water resistance. The cured product of the composition according to the invention exhibits low storage modulus loss under high humidity conditions, and preferably also low water absorption. Background Technology

[0002] Traditionally, thermosetting epoxy compositions have been used as adhesives or sealants. Cationic photocurable epoxy compositions have also been developed for various applications, particularly electronics-related ones, due to their advantages such as high efficiency, excellent storage stability, energy savings, and suitability for heat-sensitive components / modules. Cationic photocurable epoxy compositions are also advantageous because they provide cured products with physical properties comparable to thermosetting compositions, are less susceptible to oxygen inhibition than radical UV-curable compositions, and exhibit lower shrinkage rates. Therefore, cationic photocurable epoxy compositions have been used in various well-known applications, such as sealing liquid crystal displays, laminating digital discs, and sealing device packages.

[0003] Electronic devices typically require higher reliability, which is significantly affected by the physical properties of adhesive or sealant compositions, such as modulus and water absorption stability under high humidity conditions. Therefore, there is always a need to develop adhesive or sealant compositions that provide cured products with low storage modulus loss under high humidity conditions, preferably simultaneously exhibiting low water absorption.

[0004] In the prior art, the currently available method for achieving low water absorption is thermosetting, and there are also some corresponding compositions with low water absorption.

[0005] For example, KR100349313B1 (Kim Tae Seong et al.) discloses an adhesive and bonding film for semiconductor packaging that improves the reliability of semiconductor devices by reducing their moisture absorption properties. In this document, thermal curing is required.

[0006] US4767811A (Hans D. Torre et al.) discloses a thermoplastic polyamide molding compound containing an epoxy compound that exhibits reduced water absorption. Thermosetting is also required in this document.

[0007] However, thermosetting typically requires high temperatures (usually above 60°C) to achieve complete curing, which is not suitable for temperature-sensitive devices. Therefore, despite the progress made to date, there is still a need for new radiation-curable epoxy compositions that can be effectively cured without a thermosetting step and that provide cured products with low storage modulus loss under high humidity conditions, preferably with low water absorption as well. Summary of the Invention

[0008] Through in-depth research, the inventors discovered that by using specific alicyclic epoxy compounds, the cured products of the obtained adhesive compositions can achieve low storage modulus loss, and preferably low water absorption, under high humidity conditions and even at elevated temperatures. Therefore, an object of the present invention is to provide radiation-curable epoxy-based compositions that can be effectively cured without a thermal curing step, and that provide cured products with low storage modulus loss, and preferably low water absorption, under high humidity conditions.

[0009] In one aspect, a radiation-curable epoxy-based composition is provided, said radiation-curable epoxy-based composition comprising or consisting of the following components: (a) An epoxy component comprising (a-1) at least one alicyclic epoxy compound of formula (I) or consisting of (a-1) at least one alicyclic epoxy compound of formula (I): L-(A) n (I) in: - n represents an integer of 2, 3, or 4, preferably 2; - A may be the same or different, each independently representing either epoxycyclohexyl or epoxycyclopentyl; and - L does not exist, or represents a single bond, linear or branched n-valent C1-C 10 An alkane group, or a C4-C group. 15 Cycloalkanes; When L is absent, two, three, or four A groups bond directly together to form a bridged ring structure, and When L is C4-C 15 In cycloalkane structures, L forms a bridged ring structure together with one or more A groups; and (b) At least one cationic photoinitiator.

[0010] The inherent presence of a cationic photoinitiator facilitates the complete curing of the composition upon exposure to photochemical radiation. This composition has demonstrated rapid curing speed and the desired degree of curing without the need for a thermal curing step. Curing requires only a single light source, and the curing process is simplified. Furthermore, the cured composition exhibits low storage modulus loss under high humidity conditions and even at elevated temperatures, and preferably also low water absorption, thereby ensuring the reliability of electronic devices in which this composition is applied.

[0011] On the other hand, a cured product of the radiation-curable epoxy-based composition of the present invention is provided.

[0012] In another aspect, the use of the radiation-curable epoxy-based composition according to the invention for bonding, casting, molding, adhesiveting, sealing or coating in radiation-exposed areas of one or more substrates is provided, preferably for use as an adhesive or sealant.

[0013] In another aspect, articles are provided that are bonded or sealed by radiation-curable epoxy-based compositions according to the invention.

[0014] In another aspect, the alicyclic epoxy compound of formula (I) is provided for use in radiation-curable epoxy-based compositions to improve the storage modulus stability of the cured product of the epoxy-based composition, and preferably to improve water resistance simultaneously. Detailed Implementation

[0015] Those skilled in the art will understand that this discussion is merely a description of exemplary embodiments and is not intended to limit the broader aspects of the invention. Unless explicitly stated otherwise, each aspect so described may be combined with any other one or more aspects. In particular, any feature indicated as preferred or advantageous may be combined with any other one or more features indicated as preferred or advantageous.

[0016] Unless otherwise defined, all terms used in this invention (including technical and scientific terms) have the meanings commonly understood by one of ordinary skill in the art to which this invention pertains. Further guidance includes terminology definitions to better understand the teachings of this invention. In case of conflict, this invention (including the definitions) shall prevail.

[0017] Unless the context clearly indicates otherwise, the singular form used in this article is " One / a kind (a / an) "and" Place The "Including plural referents."

[0018] As mentioned in this article regarding numerical values, " about "", About "and similar terms" refers to values ​​of ±10%, preferably ±5%, more preferably ±2%. All values ​​herein should be interpreted as being expressed using the term "and similar terms". about "Modification".

[0019] Unless otherwise stated, the definition of numerical endpoints includes all numbers and fractions falling into their respective ranges, as well as the listed endpoints.

[0020] The term "component" used in this article At least one "or" One or more "This refers to the type of component, not the absolute number of molecules."

[0021] The term "in this article" Contains (comprising / comprises / comprised of) "and" include (including / includes) "or" Contains "Synonyms, including or open-ended, and do not exclude additional undescribed components, members, elements, or method steps."

[0022] When quantities, concentrations, dimensions, and other parameters are expressed in the form of ranges, preferred ranges, upper limits, lower limits, or preferred upper and lower limits, it should be understood that any range that can be obtained by combining any upper or preferred value with any lower or preferred value is also specifically disclosed, whether or not the obtained range is explicitly mentioned in the context.

[0023] The term used in this article is " It is possible / possible / may "It is used in a permissible sense (i.e., it means possible), not in a mandatory sense."

[0024] The room temperature used in this article refers to 23℃±2℃.

[0025] The term "in this article" Average particle size (D50) "50" refers to the particle size corresponding to 50% of the particles in the distribution curve, where particles are accumulated in order of particle size from the smallest to the largest, and the total number of accumulated particles is 100%. The average particle size (D50) is tested using the laser diffraction / scattering method.

[0026] The term "in this article" monomer "" refers to substances that can undergo polymerization reactions to provide structural units for the chemical structure of polymers. The term "" as used in this article Monofunctional "" refers to having an aggregateable part, and the term " polysaccharidosis "" refers to having more than one aggregateable part.

[0027] The epoxy compounds in this article undergo " Ring-opening polymerization " Ring-opening polymerization "This refers to the cyclic compounds ( monomer The polymerization of linear polymers is initiated in the presence of a suitable catalyst.

[0028] The term "in this article" Epoxy compounds "" indicates a compound characterized by the presence of at least one cyclic ether group, i.e., a compound in which the ether oxygen atom is attached to two adjacent carbon atoms to form a cyclic structure. This term is intended to cover monoepoxides, polyepoxides (having two or more epoxy groups), and epoxy-terminated prepolymers. single ring Oxygen compounds "", Diepoxide ",or" Polyepoxides "Intended to represent epoxy compounds having one epoxy group, two epoxy groups, or more than two epoxy groups respectively."

[0029] The term "in this article" Photoinitiator "" indicates a compound that can be activated by an energy-carrying activation beam (such as electromagnetic radiation), for example, upon irradiation with it. The term "" as used herein cationic photoinitiator "This refers to a cationic photoinitiator that generates cationic substances upon light irradiation and initiates the polymerization of cationically curable compounds (such as epoxy compounds).

[0030] All references cited in this article are hereby incorporated in their entirety through citation.

[0031] The radiation-curable epoxy-based composition of the present invention will be described in detail below.

[0032] Component (a): Epoxy component The compositions of the present invention comprise (a) an epoxy component as an essential component. Epoxy component (a) necessarily comprises (a-1) at least one alicyclic epoxy compound of formula (I) below, and may also comprise (a-2) one or more optional additional epoxy compounds (different from component (a-1)). In the present invention, component (a-1) preferably constitutes the major portion of the epoxy component, and the phrase "major portion" herein means that the content of component (a-1) is at least 50% by weight based on the total weight of the epoxy component in the composition.

[0033] Component (a-1): Alicyclic epoxy compound of formula (I) The epoxy component (a) necessarily contains at least one alicyclic epoxy compound of formula (I) or is composed of at least one alicyclic epoxy compound of formula (I): L-(A) n (I) in: - n represents an integer of 2, 3, or 4, preferably 2; - A may be the same or different, each independently representing either epoxycyclohexyl or epoxycyclopentyl; and - L does not exist, or represents a single bond, linear or branched n-valent C1-C 10 An alkane group, or a C4-C group. 15 Cycloalkanes; When L is absent, two, three, or four A groups bond directly together to form a bridged ring structure, and When L is C4-C 15 In cycloalkane structures, L forms a bridged ring structure together with one or more A groups.

[0034] The phrase "n-valent alkane group" here means that the alkane group has n valences, and each valence corresponds to a bonding site with the A group.

[0035] The term "epoxycyclohexyl" here has the following structure: .

[0036] The term "epoxycyclopentyl" here has the following structure: .

[0037] In some implementations, L preferably represents a single bond, a linear or branched divalent C1-C bond. 10 (Or C2-C8, or C2-C6) alkylene, or C4-C 10 Cycloalkanes.

[0038] This invention is not intended to be limited; n-valent C1-C 10 Exemplary examples of alkane groups include, but are not limited to, methylene, ethylene, n-propylene, isopropylene, n-butylene, sec-butylene, tert-butylene, n-pentylene, neopentylene, and hexylene.

[0039] Not intended to limit the invention, illustrative C4-C 15 Cycloalkane structures include, but are not limited to, cyclohexane, cycloheptane, and norbornene structures.

[0040] In a preferred embodiment, the alicyclic epoxy compound of formula (I) is one or more compounds selected from the following:

[0041] Each alicyclic epoxy compound of formula (I) may be included in the composition according to the invention in amounts of at least 3% by weight, preferably at least 20% by weight, but not more than 90% by weight, preferably not more than 80% by weight, such as 5% by weight, 15% by weight, 25% by weight, 28% by weight, 30% by weight, 35% by weight, 40% by weight, 45% by weight, 50% by weight, 57% by weight, 60% by weight, 65% by weight, 66% by weight, 67% by weight, 68% by weight, 69% by weight, 70% by weight, 75% by weight, 77% by weight, 80% by weight, 85% by weight, and 87% by weight, based on the total weight of the composition.

[0042] The inclusion of an alicyclic epoxy compound of formula (I) in the compositions of the present invention can improve the storage modulus loss of the cured composition under high humidity conditions, and preferably improve water absorption at the same time. More specifically, a higher amount of the alicyclic epoxy compound of formula (I) is more beneficial for improving the storage modulus loss of the cured composition under high humidity conditions, and preferably improves water absorption at the same time. When the epoxy component (a) is composed of an alicyclic epoxy compound of formula (I), the cured composition can simultaneously achieve excellent storage modulus loss and extremely low water absorption.

[0043] Component (a-2): One or more optional additional epoxy compounds In addition to the alicyclic epoxide (a-1) of formula (I) as described above, the compositions according to the invention may optionally contain (a-2) at least one other epoxide compound.

[0044] At least one additional epoxy compound (a-2) preferably does not constitute a major part of the epoxy component (a) in the composition. That is, based on the total weight of the epoxy components in the composition, at least one additional epoxy compound (a-2) preferably accounts for no more than 50% by weight.

[0045] Based on the total weight of the composition, each component (a-2) may be included in the composition of the present invention in the following total amounts: 0 to 50% by weight, such as 5% by weight, 10% by weight, 15% by weight, 20% by weight, 22% by weight, 25% by weight, 30% by weight, 35% by weight, 40% by weight, 44% by weight, or 48% by weight.

[0046] At least one additional epoxy compound used herein may be monofunctional or polyfunctional and does not fall within the scope of alicyclic epoxy compounds of formula (I). The additional epoxy compound may be those known in the field of epoxy-based adhesives and may be alicyclic epoxy compounds, aliphatic epoxy compounds, or aromatic epoxy compounds other than alicyclic epoxy compounds of formula (I).

[0047] Illustrative examples of alicyclic epoxides other than those of formula (I) include, but are not limited to: epoxy-substituted alicyclic hydrocarbons, such as cyclohexene oxide, vinylcyclohexene monooxide, limonene oxide, cyclooctene oxide, cyclododecene oxide, and α-pinene oxide; vinylcyclohexene diesteroxides; limonene diesteroxides; glycidyl ethers of alicyclic alcohols; glycidyl esters of alicyclic monocarboxylic acids; diglycidyl ethers of alicyclic diols (such as cyclopentanediol and cyclohexanediol); diglycidyl ethers of cyclohexanediol; bis(3, 4-Epoxycyclohexylmethyl) adipate; bis(3,4-epoxy-6-methylcyclohexylmethyl) adipate; bis(2,3-epoxycyclopentyl) ether; 3,4-epoxycyclohexylmethyl 3',4'-epoxycyclohexane carboxylate; 1,4-cyclohexanediethanol diglycidyl ether; 1,2-cyclohexanedicarboxylate diglycidyl ether; bis(2,3-epoxypropyl)cyclohexane-1,2-dicarboxylate; and alicyclic epoxy resins obtained by hydrogenation of aromatic bisphenol A diglycidyl ether (BADGE) epoxy resin.

[0048] Examples of commercially available products of this type of alicyclic epoxide include, but are not limited to: Cyracure® UVR6105, UVR6110 and UVR6128 available from Dow Chemical; Syna Epoxy S-06E available from Synasia; Celloxide 2021P available from Daicel Corporation; and S28 available from Synasia.

[0049] Illustrative examples of aliphatic or aromatic epoxy compounds include, but are not limited to: olefin oxides; epoxy-substituted aromatic hydrocarbons; epoxy-substituted alkyl ethers of monohydric alcohols or phenols, such as glycidyl ethers of aliphatic and aromatic alcohols; epoxy-substituted alkyl esters of monocarboxylic acids, such as glycidyl esters of aliphatic and aromatic monocarboxylic acids; epoxy-substituted alkyl esters of polycarboxylic acids; alkyl esters and alkenyl esters of epoxy-substituted monocarboxylic acids; epoxy-substituted alkyl ethers of polyols; and monoesters of polyols and epoxy-substituted monocarboxylic acids.

[0050] If the composition of this application contains an aromatic epoxy compound, it is preferable that the aromatic epoxy compound does not constitute a major part of the epoxy component. More preferably, the composition of this application does not contain an aromatic epoxy compound.

[0051] Preferably, the compositions of this application do not contain compounds containing epoxy lactone moieties and / or epoxy lactone moieties.

[0052] Preferably, the compositions of this application do not contain compounds having at least one functional group selected from oxetyl, vinyl ether, and (meth)acryloyl groups.

[0053] The term “not containing” here means that, based on the total weight of the composition, the composition of this application may contain less than 1% by weight, preferably less than 0.5% by weight, more preferably less than 0.1% by weight, and particularly preferably 0.0% by weight of the compound.

[0054] Component (b): Cationic photoinitiator Cationic photoinitiators are cationic photoinitiators that generate cationic substances upon light irradiation and initiate a curing reaction of cationically curable compounds. Each cationic photoinitiator comprises a cationic portion for absorbing light and an anionic portion for serving as an acid source. Component (b) may contain each of the different cationic photoinitiators, individually or in combination.

[0055] Without limiting the invention, illustrative examples of cationic photoinitiators used in the present invention include, but are not limited to, diazonium salt compounds, iodonium salt compounds, sulfonium salt compounds, phosphonium salt compounds, selenium salt compounds, oxonium salt compounds, ammonium salt compounds, and bromide salt compounds.

[0056] Sulfonium salt compounds are preferably used in this invention. Examples of the cationic moiety in sulfonium salt compounds include, but are not limited to, arylsulfonium ions (such as triphenylsulfonium ion, diphenyl[4-(phenylthio)phenyl]sulfonium ion and tri-p-tolylsulfonium ion), preferably triarylsulfonium ion.

[0057] Examples of anionic moieties in cationic photoinitiators include, but are not limited to, BF4. - B(C6F5)4 - PF6 - 、[(Rf) n PF 6-n ] - (Where Rf represents an alkyl group in which 80% or more of the hydrogen atoms are replaced by fluorine atoms; and n represents an integer from 1 to 5), AsF6 - SbF6 - And pentafluorohydroxyantimonate.

[0058] Specific examples of cationic photoinitiators include, but are not limited to, diphenyl[4-(phenylthio)phenyl]sulfonium triethyl trifluorophosphate, diphenyl[4-(phenylthio)phenyl]sulfonium tetra(pentafluorophenyl)borate, diphenyl[4-(phenylthio)phenyl]sulfonium hexafluorophosphate, diphenyl[4-(phenylthio)phenyl]sulfonium tri(pentafluoroethyl) trifluorophosphate, and (1,1''-biphenyl)-4-yl[4-(1,1''-biphenyl)4-ylphenylthio]phenyl tetra(pentafluorophenyl)borate.

[0059] Illustrative examples of commercially available products that can be used in this invention include, but are not limited to, products available under the following trade names: CYRACURE UVI-6970, CYRACURE UVI-6974, CYRACURE UVI-6990, and CYRACUREUVI-950 (each from Union Carbide Corporation, USA); IRGACURE 250, IRGACURE 261, and IRGACURE 264 (each from Ciba Specialty Chemicals Corporation); SP-150, SP-151, SP-170, and OPTOMER SP-171 (each from ADEKA CORPORATION); CG-24-61 (from Ciba Specialty Chemicals Corporation); DAICAT II (from Daicel Corporation); UVAC1590 and UVAC1591 (each from DAICEL-CYTEC Company, Ltd.); CI-2064, CI-2639, CI-2624, CI-2481, CI-2734, CI-2855, CI-2823, CI-2758, and CIT-1682 (each from Nippon Soda Co., Ltd.); PI-2074 (from Rhodia, Tolylisopropylphenyliodonium pentafluorophenylborate); FFC509 (from Minnesota Mining & Manufacturing Co.); BBI-102, BBI-101, BBI-103, MPI-103, TPS-103, MDS-103, DTS-103, NAT-103, and NDS-103 (each from Midori Kagaku Co., Ltd.); CD-1010, CD-1011, and CD-1012 (from Sartomer Company, Inc., USA); and CPI-100P, CPI-101A, and CPI-200K (each obtained from San-Apro Ltd.).

[0060] Each of the cationic photoinitiators may be included in the composition according to the invention in amounts of 0.01 to 5 wt%, preferably 0.1 to 4 wt%, more preferably 0.2 to 3 wt%, most preferably 0.5 to 2 wt%, such as 0.8 wt%, 1.0 wt%, 1.2 wt%, 1.5 wt%, 1.8 wt%, 2.2 wt%, 2.5 wt%, and 2.8 wt%, based on the total weight of the composition.

[0061] Component (c): One or more optional additives The compositions of the present invention may optionally contain one or more additives that can impart improved properties to these compositions. For example, one or more additives may impart one or more of the following: improved elasticity; improved elastic recovery; longer permissible processing time; faster curing time; and lower residual tack. Examples of one or more such additives are toughening agents, fillers, adhesion promoters, rheology modifiers (including thixotropic agents), plasticizers, stabilizers (including UV stabilizers), antioxidants, reactive / non-reactive diluents, desiccants or moisture scavengers, fungicides, flame retardants, or pigments.

[0062] One or more of these additives may be used as needed in any combination and proportion, provided that they do not adversely affect the properties and essential characteristics of the composition. For example, if present, the additives may be present in the following total amounts based on the total weight of the composition: not more than 85% by weight, preferably not more than 40% by weight, such as 80% by weight, 75% by weight, 70% by weight, 65% by weight, 60% by weight, 55% by weight, 50% by weight, 45% by weight, 40% by weight, 35% by weight, 30% by weight, 25% by weight, 20% by weight, 15% by weight, and 10% by weight.

[0063] <packing> The compositions of the present invention may optionally contain one or more fillers as additives. Various fillers may be used alone or in combination.

[0064] Generally, there is no intention to particularly limit the shape of the particles used as fillers: needle-like, spherical, ellipsoidal, cylindrical, bead-like, cubic, or plate-like particles can be used alone or in combination. Furthermore, it is envisioned that aggregates of more than one particle type can be used. Similarly, there is no intention to particularly limit the size of the particles used as fillers. However, the average particle size (d50) of such fillers, as measured by laser diffraction / scattering, will typically be from 0.1 to 1000 μm, for example, from 1 to 500 μm.

[0065] Exemplary fillers include, but are not limited to: graphite, carbon black, calcium carbonate, calcium oxide, calcium chloride, calcium hydroxide (lime powder), calcium sulfate, fused silica, amorphous silica, precipitated silica and / or pyrolytic silica, zeolite, bentonite, wollastonite, magnesium carbonate, magnesium sulfate, diatomaceous earth, barium sulfate, barium oxide, aluminum oxide, aluminum nitride, boron nitride, clay, talc, titanium oxide, iron oxide, zinc oxide, sand, quartz, flint, mica, glass beads, glass powder, and other ground minerals. Organic fillers may also be used, particularly wood fiber, wood flour, sawdust, cellulose, cotton, pulp, cotton, sawdust, chopped straw, rice husks, ground walnut shells, and other chopped fibers; poly(tetrachloroethylene), poly(trifluoroethylene), and poly(vinylidene chloride) powders may also be used. Additionally, short fibers such as glass fiber, glass filament, polyacrylonitrile, carbon fiber, Kevlar fiber, or polyethylene fiber may be added.

[0066] Fillers that impart thixotropic properties to a composition may be preferred for many applications: such fillers are also described as thixotropic agents, such as fumed silica, hydrogenated castor oil, fatty acid amides, or modified silica, alumina, and / or modified alumina. Non-limiting illustrative examples of such thixotropic fillers are commercially available from Cabot Corporation using Cab-O-Sil TS720.

[0067] The desired viscosity of the resulting curable composition can determine the amount of filler used. The total amount of filler should not impede the ease with which the composition can be applied to the substrate by the chosen method for applying the composition. Each filler may be included in the compositions of the invention in amounts of: 0.1 to 80 wt%, preferably 5 to 65 wt%, such as 8 wt%, 10 wt%, 11 wt%, 12 wt%, 15 wt%, 18 wt%, 20 wt%, 22 wt%, 25 wt%, 28 wt%, 30 wt%, 32 wt%, 35 wt%, 38 wt%, 40 wt%, 42 wt%, 45 wt%, 48 wt%, 50 wt%, 52 wt%, 55 wt%, 58 wt%, 60 wt%, 79 wt%, based on the total weight of the composition.

[0068] Toughening agent The compositions of the present invention may also contain a toughening agent as an additive. There are no particular limitations on the toughening agents that can be used in the present invention, and those toughening agents conventionally used in epoxy-based adhesives may be used in the present invention.

[0069] Non-limiting examples of toughening agents applicable to the present invention include: - OH or acid-terminated polyols, such as polyethers (PEG, PPG, PTHF and Velvetol) and polyesters (polyester polyols, polyester diols, fatty acid-modified bisphenol A diglycidyl ether). - Core-shell particles, such as PMMA shells and styrene-polybutadiene cores or polybutadiene cores or polysiloxane cores; - Non-reactive toughening rubber-like materials and fillers, such as end-capped elastomer urethanes, block copolymer rubbers (such as styrene-butadiene-isoprene-based block copolymers, styrene-isoprene-styrene block copolymers, and other rubber-like block copolymers). - Reactive toughening rubbery materials, such as liquid rubbers having two or more epoxy reactive groups (e.g., amine-terminated, OH-terminated, and acid-terminated), such as butadiene-acrylonitrile-based rubbers, carboxyl-terminated butadiene-acrylonitrile (CTBN) with different acrylonitrile (AN) contents, amino-terminated butadiene-acrylonitrile (ATBN), epoxy-terminated butadiene-acrylonitrile (ETBN), and vinyl-terminated butadiene-acrylonitrile (VTBN); OH-terminated polyether polyols (PEG, PPG, PTHF type, 1,3-propanediol-based), OH-terminated polyethers based on cashew nut shell liquid, OH-terminated or acid-terminated polyesters, OH-terminated thermoplastic polyurethanes, HTPB (hydroxyl-terminated polybutadiene), epoxidized HTPB, polyfarnes based on polyene, amine-terminated polyethers (Jeff amines), epoxy-terminated elastomeric polyethers or polyesters (e.g., based on dimer fatty acids).

[0070] Illustrative examples of commercially available toughening agents include, but are not limited to, Voranol CP450 from Dow.

[0071] Excessive toughening agent content leads to poor adhesion properties, poor Tg value, and undesirable viscosity, while insufficient content results in a brittle system. Based on the total weight of the composition, the toughening agent may be included in the compositions of the present invention in amounts of: 1 to 50 wt%, preferably 4 to 40 wt%, such as 3 wt%, 8 wt%, 10 wt%, 12 wt%, 15 wt%, 18 wt%, 20 wt%, 22 wt%, 25 wt%, 28 wt%, 30 wt%, 32 wt%, 35 wt%, 38 wt%, 42 wt%, and 45 wt%.

[0072] <Adhesion Promoter> Adhesion accelerators can be added as additives to the compositions of the present invention to improve the adhesion between the epoxy resin and the substrate. The choice of adhesion accelerator can be determined by the type of surface on which the composition will be applied.

[0073] Commonly used commercial adhesion promoters are organosilanes, such as epoxy-modified silanes, like glycidyl-modified silanes, particularly trimethoxysilanes, preferably glycidoxypropyltrimethoxysilane. Other types of adhesion promoters that can be used herein include: organometallic compounds, such as titanates and zirconates, specific examples of which include isopropyltris(N-ethylaminoethylamino)titanate, tetraisopropyldi(dioctylphosphito)titanate, neoalkoxytrinedecyl zirconate, and zirconium propionate; dihydroxyphenolic compounds, such as catechol and thiodiol; polyphenols, such as biphenyl pyrogallol, gallic acid, or tannic acid; phosphate esters, such as tricresyl phosphate; and plasticizers, which are suspensions of polyvinyl chloride particles in a plasticizer.

[0074] Non-limiting illustrative examples of commercially available adhesion promoters include Glymo, available from Evonik, and Silquest, available from Momentive (such as Silquest A-187).

[0075] Based on the total weight of the composition, the adhesion promoter may be included in the composition of the present invention in the following amounts: 0.01 to 5 wt%, preferably 0.1 to 2.5 wt%, more preferably 0.5 to 1.5 wt%, such as 0.05 wt%, 0.15 wt%, 0.2 wt%, 0.5 wt%, 0.8 wt%, 0.9 wt%, 1.0 wt%, 1.2 wt%, 1.5 wt%, 1.8 wt%, 2.0 wt%, 2.2 wt%, 2.8 wt%, 3.0 wt%, 3.5 wt%, 4.0 wt%, 4.5 wt%.

[0076] <Other Additives> The word "can be used in this application" plasticizer This is to reduce the viscosity of the composition and thus improve its processability. In this document, based on the total weight of the composition, the plasticizer may comprise up to 10% by weight or up to 5% by weight, and is preferably selected from: dicarboxylate; monofunctional linear or branched C4-C... 16 Ethers of alcohols; rosin esters, adipates, sebates, butyrates, thiobutyrates, acetates, propionates, and citrates; esters based on nitrocellulose and polyvinyl acetate; fatty acid esters; dicarboxylic acid esters; esters of fatty acids with OH groups or epoxidized fatty acids; glycolates; benzoates; phosphate esters; sulfonates; trimellitates; polyether plasticizers, such as terminally capped polyethylene glycol or polypropylene glycol; polystyrene; hydrocarbon plasticizers; chlorinated paraffins; and mixtures thereof. It should be noted that phthalates can be used as plasticizers in principle, but they are not preferred due to their toxicological potential.

[0077] “ stabilizer "Should be understood as antioxidant, UV stabilizer, heat stabilizer, or hydrolytic stabilizer. In this document, stabilizers may comprise up to 10% by weight or up to 5% by weight based on the total weight of the composition. Standard commercial examples of stabilizers applicable to this document include: sterically hindered phenols; thioethers; benzotriazoles; benzophenones; benzoates; cyanoacrylates; acrylates; hindered amine light stabilizers (HALS) type amines; phosphorus; sulfur; and mixtures thereof."

[0078] Uses of alicyclic epoxides of formula (I) This document also provides the use of an alicyclic epoxy compound of formula (I) in a radiation-curable epoxy-based composition for improving the storage modulus stability of the cured product of the epoxy-based composition, and preferably simultaneously improving water resistance, wherein the alicyclic epoxy compound of formula (I) is the same as defined above.

[0079] The radiation-curable epoxy-based compositions described herein may have the same definitions as those described in the first aspect.

[0080] In particular, for the purposes of such uses, the alicyclic epoxy compound of formula (I) may be included in the radiation-curable epoxy-based composition in amounts of at least 3% by weight, preferably at least 5% by weight, more preferably at least 20% by weight, but not more than 90% by weight, preferably not more than 80% by weight, such as 4% by weight, 5% by weight, 15% by weight, 22% by weight, 28% by weight, 30% by weight, 35% by weight, 40% by weight, 45% by weight, 50% by weight, 57% by weight, 60% by weight, 65% by weight, 66% by weight, 67% by weight, 68% by weight, 69% by weight, 70% by weight, 75% by weight, 77% by weight, 80% by weight, 85% by weight, and 87% by weight, respectively, based on the total weight of the composition.

[0081] The inventors have unexpectedly discovered that even a very small amount of the alicyclic epoxy compound of formula (I) can improve the storage modulus stability of the cured product of the epoxy-based composition, and preferably simultaneously improve water resistance. For example, a content of only 5% by weight of the alicyclic epoxy compound of formula (I) based on the total weight of the composition can significantly improve the storage modulus loss of the cured composition under high humidity conditions, and even simultaneously improve water absorption. The inventors have also found that higher amounts of the alicyclic epoxy compound of formula (I) are more conducive to improving the storage modulus loss of the cured composition under high humidity conditions, and even simultaneously improving water absorption; and in some cases, the higher the content of the alicyclic epoxy compound of formula (I), the more significant the improvement.

[0082] Methods and Applications To form the defined curable composition, the components are gradually or all at once combined and mixed. Importantly, mixing ensures that the components are uniformly distributed within the composition. For example, a radiation-curable epoxy-based composition according to the invention can be prepared by the following steps: mixing (a) an epoxy component comprising at least one alicyclic epoxy compound of formula (I), (b) at least one cationic photoinitiator, and one or more optional additional components into a homogeneous mixture. Preferably, one or more mixing steps are performed under yellow light.

[0083] The obtained mixture can then be applied to the surface to be bonded in any manner known in the art. The composition can be applied to the optionally pretreated, optionally primed surface of the substrate by conventional application methods such as printing, including screen printing; pin transfer; and syringe application, including via an electro-pneumatically controlled syringe.

[0084] Given that the composition contains a photoinitiator, the energy source used to initiate the curing of the applied composition will emit at least one of ultraviolet (UV) radiation, infrared (IR) radiation, visible light, X-rays, gamma rays, or an electron beam (e-beam). Upon application, when irradiated using commercial curing equipment, the photocurable composition can typically be activated in less than 5 minutes, usually between 1 and 60 seconds (e.g., between 3 and 12 seconds). Useful UV light sources include, for example, ultra-high pressure mercury lamps, high pressure mercury lamps, medium pressure mercury lamps, low-intensity fluorescent lamps, metal halide lamps, microwave-powered lamps, xenon lamps, UV-LED lamps, and laser beam sources (such as excimer lasers and argon ion lasers).

[0085] It is not intended to limit the substrates to which the compositions of the present invention can be applied. Those skilled in the art will recognize those substrates conventionally present in optoelectronic or optomechanical devices. However, references may be made to: polymers such as polyvinyl chloride, polyolefins, and polycarbonates; carbon and nanocarbon substrates; metals such as Al, Pb, Sn, Ge, Si, Ti, Bi, In, Ni, and Fe; anodized metals, particularly anodized aluminum; alloys such as brass and stainless steel; semiconductor materials such as Si, GaAs, InP, GaP, GaSb, and InAs; ceramics, including silicon dioxide, zirconium oxide, ceramic ferrules, piezoelectric ceramics, and dielectric ceramics; and glasses, including FTO / ITO glasses, glass-polymer hybrids, and glasses modified thereon with a conductive layer.

[0086] Example The present invention will now be further described and explained in detail with reference to the following embodiments. These embodiments are intended to help those skilled in the art to better understand and practice the present invention, but are not intended to limit the scope of the invention in any way.

[0087] Preparation of radiation-curable epoxy-based compositions The radiation-curable epoxy-based composition of the present invention is prepared by the following steps: - The epoxy component, cationic photoinitiator, and optional additional additives, excluding fillers and thixotropic agents, are mixed together to form a homogeneous mixture; and - Add the filler and thixotropic agent (if present) to the resulting mixture in the Speedmixer™ DAC400 and mix to form a homogeneous blend. All steps were performed under yellow light.

[0088] LED curing and physical state evaluation 1 g of each prepared curable composition was placed on a glass plate and then irradiated with a UV irradiator manufactured by UVATA at 365 nm - UV-LED (700 mW / cm²). 2 Irradiate for 10 seconds. Afterward, pierce the resulting composition with a bamboo skewer to evaluate the physical state of the composition (i.e., solid or liquid).

[0089] Water absorption rate test method Two g of each curable composition was placed on a circular mold to prepare a specimen with a diameter of 55 mm and a depth of 0.5 mm. Subsequently, a UV irradiator manufactured by UVATA was used with a 365 nm UV-LED (700 mW / cm²). 2 The sample was irradiated for 10 seconds and then left at room temperature for 24 hours. The sample was then stored in a humidity chamber for 3 days under aging conditions of 65°C and 90% RH (relative humidity), and the water absorption rate was measured by weighing. The water absorption rate was calculated using the following formula: in: - W1 is the weight of the sample before aging in the humidity chamber, in grams; and - W2 is the weight of the sample after aging in a humidity chamber, in grams.

[0090] Test methods for energy storage modulus loss Two g of each composition was placed on a mold to prepare a specimen measuring 30 mm × 5 mm × 0.5 mm. Subsequently, a UV irradiator manufactured by UVATA was used with a 365 nm UV-LED (700 mW / cm²). 2The sample was irradiated for 10 seconds and then left at room temperature for 24 hours. The sample was then stored in a humidity chamber for 3 days under aging conditions of 65°C and 90% RH, and the storage modulus loss was measured by DMA using a time-scan mode at 25°C for 5 minutes. The storage modulus loss was calculated using the following formula: in: - It is the storage modulus of the sample before aging in a humidity chamber, in MPa; and - It is the storage modulus of the sample after aging in a humidity chamber, in MPa.

[0091] Since the energy storage modulus loss is negative, it is presented as an absolute value below for comparison.

[0092] Evaluation criteria for energy storage modulus loss The evaluation criterion for energy storage modulus loss is based on its absolute value: - Values ​​greater than 35% are rated as "poor"; - Values ​​between 25% and 35% are rated as "average"; - Values ​​between 15% and 25% are rated as "good"; and - Values ​​less than 15% are rated as "excellent".

[0093] In Tables 1-4 below, the symbol "Ex." indicates an embodiment according to the present invention, while the symbol "CEx." indicates a comparative example. All values ​​related to the amount of components shown in Tables 1-4 below are in grams.

[0094] The following materials are used in the examples.

[0095] Examples 1-4 and Comparative Examples 1-2 Formulations CEx. 1 to CEx. 2 and Ex. 1 to Ex. 4 were prepared according to the composition information provided in Table 1 below. Once prepared, these formulations were cured and their physical states, water absorption, and storage modulus loss were tested according to the test methods described above. The test results are also shown in Table 1.

[0096] Table 1. Composition and performance test results of the curable composition

[0097] All formulations of CEx. 1 to CEx. 2 and Ex. 1 to Ex. 4 were subjected to UV irradiation at 365nm UV-LED (700 mW / cm²). 2After 10 seconds of irradiation, all of them solidified into solids, thus demonstrating that the composition of the present invention solidifies rapidly and efficiently under light irradiation.

[0098] Compared to Cex. 1 and Cex. 2, all cured formulations from Cex. 1 to Cex. 4 exhibited significantly lower storage modulus loss after being stored in a humidity chamber for 3 days under aging conditions of 65°C and 90% RH. Furthermore, all cured formulations from Cex. 1 to Cex. 4 also showed significantly lower water absorption than the cured formulations of Cex. 1 and Cex. 2.

[0099] Examples 5-6 Formulations Ex. 5 to Ex. 6 were prepared according to the composition information provided in Table 2 below. Once prepared, these formulations were cured and their physical states, water absorption, and storage modulus loss were tested according to the test methods described above. The test results are also shown in Table 2. For ease of comparison, CEx. 1 and CEx. 2 and Ex. 2 are reproduced in Table 2.

[0100] Table 2. Composition and performance test results of the curable composition

[0101] Similarly, all formulations from Ex. 5 to Ex. 6 were irradiated with a UV irradiator at 365nm - UV-LED (700 mW / cm²). 2 After 10 seconds of irradiation, all of them solidified into solids, thus demonstrating that the composition of the present invention solidifies rapidly and efficiently under light irradiation.

[0102] Compared to Cex. 1 and Cex. 2, all cured formulations from Cex. 5 to Cex. 6 exhibited significantly lower storage modulus loss after being stored in a humidity chamber for 3 days under aging conditions of 65°C and 90% RH. Furthermore, all cured formulations from Cex. 5 to Cex. 6 also showed significantly lower water absorption than the cured formulations from Cex. 1 and Cex. 2.

[0103] Furthermore, it can be unexpectedly observed from CEx. 1, Ex. 5, Ex. 6, and Ex. 2 that as more (a-2-1) is replaced by (a-1-2) (in other words, as the amount of (a-1-2) increases), the storage modulus loss of the cured formulation gradually decreases, and this also applies to water absorption. This clearly demonstrates that the inclusion of an alicyclic epoxy compound of formula (I) in the composition can significantly improve the storage modulus loss of the cured composition under high humidity conditions, and even simultaneously improve water absorption; and the higher the content of the alicyclic epoxy compound of formula (I), the more significant the improvement.

[0104] Example 7 The formulation of Ex. 7 was prepared according to the composition information provided in Table 3 below. Once prepared, the formulation was cured and its physical state, water absorption, and storage modulus loss were tested according to the test methods described above. The test results are also shown in Table 3. For ease of comparison, CEx. 1 to CEx. 2 and Ex. 1 are reproduced in Table 3.

[0105] Table 3. Composition and performance test results of the curable composition

[0106] Similarly, the formulation of Ex. 7 was prepared using a UV irradiator with a 365nm UV-LED (700 mW / cm²). 2 After irradiation for 10 seconds, it solidifies into a solid, thus demonstrating that the composition of the present invention cures rapidly and efficiently under light irradiation.

[0107] Compared to Cex. 1 and Cex. 2, the cured formulation of Ex. 7 exhibited a significantly lower loss of storage modulus after being stored in a humidity chamber for 3 days under aging conditions of 65°C and 90% RH. Simultaneously, the cured formulation of Ex. 7 also showed a lower water absorption rate than the cured formulations of Cex. 1 and Cex. 2.

[0108] Furthermore, it can be unexpectedly observed from CEx. 1, Ex. 1, and Ex. 7 that as more (a-2-1) is replaced by (a-1-1) (in other words, as the amount of (a-1-1) increases), the storage modulus loss of the cured formulation gradually decreases, and this also applies to water absorption. This clearly demonstrates that the inclusion of alicyclic epoxy compounds of formula (I) in the composition can significantly improve the storage modulus loss of the cured composition under high humidity conditions, and even simultaneously improve water absorption; and the higher the content of alicyclic epoxy compounds of formula (I), the more significant the improvement.

[0109] Example 8 and Comparative Example 3 Formulations of CEx. 3 and Ex. 8 were prepared according to the composition information provided in Table 4 below. Once prepared, the formulations were cured and their physical states, water absorption, and storage modulus loss were tested according to the test methods described above. The test results are also shown in Table 4.

[0110] Table 4. Composition and performance test results of the curable composition

[0111] Similarly, formulations of CEx. 3 and Ex. 7 were prepared using a UV irradiator at 365 nm UV-LED (700 mW / cm²). 2 After irradiation for 10 seconds, it solidifies into a solid, thus demonstrating that the composition of the present invention cures rapidly and efficiently under light irradiation.

[0112] Furthermore, it was unexpected that replacing 5 g of (a-2-1) with 5 g of (a-1-2) improved the storage modulus loss of the cured composition and even simultaneously improved the water absorption rate. In other words, including a small amount of the alicyclic epoxy compound of formula (I) in the composition can improve the storage modulus loss of the cured composition under high humidity conditions and even simultaneously improve the water absorption rate. This is consistent with the above conclusions.

[0113] Although some preferred embodiments have been described, many modifications and variations can be made to them based on the above teachings. Therefore, it should be understood that the invention can be practiced in ways different from those specifically described without departing from the scope of the appended claims.

Claims

1. A radiation-curable epoxy-based composition, said radiation-curable epoxy-based composition comprising: (a) An epoxy component comprising (a-1) at least one alicyclic epoxy compound of formula (I): L-(A) n (I) in: - n represents 2, 3, or 4, preferably 2; - A may be the same or different, each independently representing either epoxycyclohexyl or epoxycyclopentyl; and - L does not exist, or represents a single bond, linear or branched n-valent C1-C 10 An alkane group, or a C4-C group. 15 Cycloalkanes; When L is absent, two, three, or four A groups bond directly together to form a bridged ring structure, and When L is C4-C 15 In cycloalkane structures, L forms a bridged ring structure together with one or more A groups; and (b) At least one cationic photoinitiator.

2. The use of the alicyclic epoxy compound of formula (I) in a radiation-curable epoxy-based composition for improving the storage modulus stability of the cured product of the epoxy-based composition, and preferably simultaneously improving water resistance. L-(A) n (I) in: - n represents 2, 3, or 4, preferably 2; - A may be the same or different, each independently representing either epoxycyclohexyl or epoxycyclopentyl; and - L does not exist, or represents a single bond, linear or branched n-valent C1-C 10 An alkane group, or a C4-C group. 15 Cycloalkanes structure When L is absent, two, three, or four A groups bond directly together to form a bridged ring structure, and When L is C4-C 15 In cycloalkane structures, L forms a bridged ring structure together with one or more A groups.

3. The use according to claim 2, wherein, In addition to the alicyclic epoxy compound of formula (I) as an epoxy component, the radiation-curable epoxy-based composition also contains at least one cationic photoinitiator.

4. The composition according to claim 1 or the use according to claim 2 or 3, wherein L represents a single bond, a linear or branched divalent C1-C bond. 10 Alkylene, or C4-C 10 The cycloalkane structure preferably represents a single bond, a linear or branched divalent C2-C8 alkylene group, a cyclohexane structure, a cycloheptane structure, or a norbornene structure.

5. The composition according to claim 1 or 4, or the use according to any one of claims 2-4, wherein the alicyclic epoxy compound of formula (I) is one or more compounds selected from the group consisting of: （I-1）； （I-2）； (I-3); and （I-4）。 6. The composition according to any one of claims 1 and 4-5, or the use according to any one of claims 2-5, wherein, Based on the total weight of the composition, the alicyclic epoxy compound of formula (I) is present in an amount of at least 3% by weight, preferably at least 20% by weight, but not more than 90% by weight, preferably not more than 80% by weight.

7. The composition according to any one of claims 1 and 4-6, or the use according to any one of claims 3-6, The cationic photoinitiator is selected from diazonium salts, iodonium salts, sulfonium salts, phosphonium salts, selenium salts, oxonium salts, ammonium salts, and bromide salts, such as diphenyl[4-(phenylthio)phenyl]sulfonium triethyltrifluorophosphate; and / or in, Based on the total weight of the composition, the cationic photoinitiator is present in an amount of at least 0.01 wt%, preferably at least 0.5 wt%, but not more than 5 wt%, preferably not more than 2 wt%.

8. The composition according to any one of claims 1 and 4-7 or the use according to any one of claims 3-7, wherein the epoxy component further comprises (a-2) at least one additional epoxy compound different from the alicyclic epoxy compound of formula (I), the total amount of which is preferably 0 to 50% by weight, such as 0 to 45% by weight, based on the total weight of the composition.

9. The composition according to any one of claims 1 and 4-8, or the use according to any one of claims 2-8, The composition further comprises one or more additives selected from toughening agents, fillers, adhesion promoters, rheology modifiers including thixotropic agents, plasticizers, stabilizers including UV stabilizers, antioxidants, reactive / non-reactive diluents, desiccants or moisture scavengers, fungicides, flame retardants, pigments, and combinations thereof; and / or in, Based on the total weight of the composition, the additive is present in a total amount not exceeding 85% by weight, preferably not exceeding 40% by weight.

10. The composition according to any one of claims 1 and 4-9 or the use according to any one of claims 2-9, wherein the composition comprises: 3 to 90% by weight, preferably 20 to 80% by weight, of the alicyclic epoxy compound of formula (I); 1 to 50% by weight, preferably 4 to 40% by weight, of toughening agent, preferably polyol; 0.1 to 80% by weight, preferably 5 to 65% by weight, of filler, preferably silica; 0.01 to 5% by weight, preferably 0.1 to 4% by weight, of a photoinitiator, preferably a sulfonium salt; 0.01 to 5% by weight, preferably 0.1 to 2.5% by weight, of an adhesion promoter, preferably a silane; and 0 to 5% by weight, preferably 0.1 to 2.5% by weight, of a thixotropic agent, preferably fumed silica. The total weight percentage of all components is 100% by weight, and is based on the total weight of the composition.

11. The composition according to any one of claims 1 and 4-10 or the use according to any one of claims 2-10, wherein the composition does not contain an aromatic epoxy compound, a compound containing an epoxy lactone moiety and / or an epoxy lactone moiety, or a compound containing at least one functional group selected from oxetane, vinyl ether and (meth)acryloyl groups.

12. The cured product of the radiation-curable epoxy-based composition according to any one of claims 1 and 4-11.

13. The use of the radiation-curable epoxy-based composition according to any one of claims 1 and 4-11 for bonding, casting, molding, adhesiveting, sealing or coating in a radiation-exposed area of ​​one or more substrates, preferably for use as an adhesive or sealant.

14. Articles bonded or sealed by a radiation-curable epoxy-based composition according to any one of claims 1 and 4-11.

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