One-component curable epoxy composition

Abstract

The present invention provides a one-component curable epoxy composition comprising the following: (A) 20 to 90% by weight of a non-aromatic epoxy resin based on the total weight of the composition; (B) Non-aromatic curing agents and, optionally, non-aromatic accelerators which are a combination of dicyandiamide and a non-aromatic urea accelerator, or the following general formula (I): [Formula 1] Dihydrazides represented by TIFF2026516530000017.tif1875 (where R is an organic group that does not contain a heterocycle); (C) UV stabilizers; and (D) Rubber having a core-shell structure. The present invention further provides a cured product of the one-component curable epoxy composition, an article containing the cured product, and the use of the one-component curable composition or the cured product in an electronic device.

Description

Technical Field

[0001] The present invention relates to a one-component curable epoxy composition, and particularly to a one-component curable epoxy composition that exhibits both color stability and good adhesive strength upon curing, a cured product thereof, an article containing the cured product, and the use of the composition or the cured product thereof.

Background Art

[0002] Curable epoxy-based materials are well known. Such compositions are used as adhesives, coating agents, sealing agents, and can also be used as casting agents. Epoxy-based compositions are also used in the electronics industry. However, conventional epoxy-based materials have unstable colors: they yellow and / or darken when exposed to heat, ultraviolet light, or household chemicals. This instability restricts their application, at least in part, to cosmetic uses, for example, in adhesive applications in visible areas of the outer parts of electronic devices. Therefore, for certain cosmetic uses, color-stable epoxy-based adhesives are required.

[0003] Electronic devices or electronic device components are often subjected to further processing steps after an adhesive has been applied to the electronic device or electronic device component. For example, certain aluminum electronic device components can be subjected to chemical anodic oxidation treatment or dye injection treatment at a later stage of device construction. These treatments all involve harsh chemical treatments. Conventional epoxy-based materials cannot be used for cosmetic applications because they significantly yellow or darken under these conditions. Therefore, in addition to excellent adhesiveness and color stability in the presence of heat, ultraviolet light, or household chemicals, for some applications, an epoxy material with color stability even when subjected to chemical anodic oxidation treatment or dye injection treatment is desired.

Summary of the Invention

Problems to be Solved by the Invention

[0004] In view of the above, it is desirable to provide a one-component curable epoxy composition that exhibits both color stability and good adhesion upon curing, and in particular, a combination of low color change in the Q-sun test, low color change of the metal after anodizing, and strong adhesion to the metal. [Means for solving the problem]

[0005] The present invention provides a one-component curable epoxy composition comprising the following: (A) 20 to 90% by weight of a non-aromatic epoxy resin based on the total weight of the composition; (B) Non-aromatic curing agents and, optionally, non-aromatic accelerators which are a combination of dicyandiamide and a non-aromatic urea accelerator, or the following general formula (I): [ka] Dihydrazides represented by the formula (wherein R is an organic group that does not contain a heterocycle); (C) UV stabilizers; and (D) Rubber having a core-shell structure.

[0006] The present invention also provides a cured product of the one-component curable epoxy composition of the present invention.

[0007] The present invention further provides articles comprising the cured product of the present invention.

[0008] Furthermore, the present invention provides for the use of the one-component curable epoxy composition of the present invention in electronic devices.

[0009] The one-component curable epoxy composition, cured product, article, and use of the present invention are all based on the following remarkable discovery by the inventors: The one-component curable epoxy composition of the present invention, comprising a combination of components (A) to (D), exhibits both color stability and good adhesion upon curing, particularly a combination of low color change after Q-sun testing, low color change after metal anodizing, and strong adhesion to metals. In particular, the composition demonstrates a combination of ΔE94 color change ≤ 3 after Q-sun testing at 150 and 250 hours at 2.5 W, ΔE94 color change ≤ 3 after pickling in metal anodizing, Ti to Ti lap shear strength ≥ 20 MPa, and AnAl (anodic aluminum oxide) to AnAl lap shear strength ≥ 20 MPa. [Modes for carrying out the invention]

[0010] Those skilled in the art will understand that this discussion is for illustrative purposes only and is not intended to limit the broader aspects of the present invention. Each of the aspects described herein can be combined with any other aspect unless explicitly stated otherwise. In particular, any feature indicated as preferred or advantageous can be combined with any other feature indicated as preferred or advantageous.

[0011] Unless otherwise specified, the terms “a,” “an,” and “the” as used herein include both singular and plural references. That is, the terms “a,” “an,” and “the” are used synonymously with “at least one,” meaning one or more of the elements being described.

[0012] As used herein, the terms “comprising” and “comprises” are synonymous with “including,” “includes,” “containing,” or “contains,” and are inclusive or open-ended, not excluding any additional components, elements, or process steps not described herein.

[0013] As used herein, the term "non-aromatic" refers to a compound that does not contain an aryl group or an arylene group.

[0014] When used herein, the ΔE94 color change is measured according to the ASTM E1347-06(2020) standard.

[0015] When used herein, the lap shear strength is measured according to the ASTM D1002-10 (2019) standard.

[0016] Unless otherwise specified, the notation of endpoints in a number includes not only the endpoint itself, but also all numbers and fractions contained within that range.

[0017] Unless otherwise defined, all terms used in the disclosure of this invention, including technical and scientific terms, have the meanings generally understood by those skilled in the art to which this invention pertains.

[0018] According to the present invention, the inventors of the present invention have surprisingly provided a one-component curable epoxy composition comprising the following: (A) 20 to 90% by weight of a non-aromatic epoxy resin based on the total weight of the composition; (B) Non-aromatic curing agents and, optionally, non-aromatic accelerators which are a combination of dicyandiamide and a non-aromatic urea accelerator, or the following general formula (I): [ka] Dihydrazides represented by the formula (wherein R is an organic group that does not contain a heterocycle); (C) UV stabilizers; and (D) Rubber with core-shell structure However, we found that once cured, it can exhibit both color stability and good adhesion.

[0019] In a first embodiment, the disclosure generally relates to a one-component curable epoxy composition comprising: (A) 20 to 90% by weight of a non-aromatic epoxy resin, based on the total weight of the composition; (B) A non-aromatic curing agent and optionally a non-aromatic accelerator which is a combination of dicyandiamide and a non-aromatic urea accelerator, or the following general formula (I):

Chemical formula

[0020] (A) Non-aromatic epoxy resin According to the present invention, the one-component curable epoxy composition contains (A) 20 to 90% by weight of a non-aromatic epoxy resin, based on the total weight of the composition. In some embodiments, the non-aromatic epoxy resin is the main reactive component of the one-component curable epoxy composition of the present invention.

[0021] Preferably, non-aromatic epoxy resins include diglycidyl ether-based epoxy resins and alicyclic epoxy resins, such as diepoxy acetal, diepoxy adipate, diepoxy carboxylate, and dicyclopentadiene-based epoxy resins; isocyanurate derivative epoxy resins, such as triglycidyl isocyanurate; and hydrogenated epoxy resins prepared by hydrogenating aromatic rings in aromatic epoxy resins such as bisphenol A epoxy resin, bisphenol F epoxy resin, phenol novolac epoxy resin, cresol novolac epoxy resin, naphthalene epoxy resin, biphenyl epoxy resin, aralkyl epoxy resin, and biphenylaralkyl epoxy resin. Two or more of these resins can also be used in combination. More preferably, the non-aromatic epoxy resin is a hydrogenated epoxy resin prepared by hydrogenating aromatic rings in aromatic epoxy resins such as bisphenol A epoxy resin, bisphenol F epoxy resin, phenol novolac epoxy resin, cresol novolac epoxy resin, naphthalene epoxy resin, biphenyl epoxy resin, aralkyl epoxy resin, and biphenylaralkyl epoxy resin. Most preferably, the non-aromatic epoxy resin is a hydrogenated bisphenol A epoxy resin.

[0022] Examples of commercially available non-aromatic epoxy resins include, but are not limited to, JER YX-8000D, JER YX-8034, and JER YX-8040 from Mitsubishi Chemical Corporation, and EPALLOY® 5000 from Huntsman Corporation. Preferably, the non-aromatic epoxy resin is the one traded under the name JER-YX 8000D from Mitsubishi Chemical Corporation.

[0023] In a preferred embodiment of the present invention, the amount of non-aromatic epoxy resin is 30 to 90% by weight, preferably 42 to 85% by weight, and more preferably 42 to 80% by weight, based on the total weight of the composition. If the amount of non-aromatic epoxy resin is greater than 90% by weight, the adhesion of the composition to metal will be reduced. If the amount of non-aromatic epoxy resin is less than 20% by weight, the color stability of the composition will be poor.

[0024] In a preferred embodiment of the present invention, the one-component curable epoxy composition does not contain an aromatic epoxy resin.

[0025] (B) Non-aromatic curing agent and optionally non-aromatic accelerator According to the present invention, a one-component curable epoxy composition comprises (B) a non-aromatic curing agent and optionally a non-aromatic accelerator which is a combination of dicyandiamide and a non-aromatic urea accelerator, or the following general formula (I): [ka] (In the formula, R is an organic group that does not contain a heterocycle.) It contains dihydrazide, represented by [the formula shown].

[0026] Combination of dicyandiamide and non-aromatic urea enhancer In one embodiment of the present invention, the one-component curable epoxy composition includes a combination of dicyandiamide and a non-aromatic urea accelerator as component (B).

[0027] Dicyandiamide has the following general chemical structure: [ka]

[0028] Examples of commercially available dicyandiamides include, but are not limited to, Omicure DDA 5, Omicure DDA 10, Omicure DDA 50, and Omicure DDA 100 (all from Huntsman); Dicyanex 1400B, Amicure CG-1200G, Amicure CG-325G, and Dicyanex 1400 F (all from Evonik); and Dyhard 100, Dyhard 1100S, Dyhard 100SH, Dyhard 100SF, and Ecure 14 (all from Alzchem Group). Preferably, the dicyandiamide is the one traded under the name Omicure DDA 5 from Huntsman.

[0029] The non-aromatic urea accelerator can be any conventional non-aromatic urea accelerator in the art used with dicyandiamide, provided that it does not adversely affect the desired technical effects of the composition of the present invention. Preferably, the non-aromatic urea accelerator is a cycloaliphatic-substituted urea. More preferably, the non-aromatic urea accelerator is an isophorone diurea.

[0030] Examples of commercially available non-aromatic urea accelerators include, but are not limited to, Omicure U 35 M from Huntsman.

[0031] In a preferred embodiment of the present invention, the amounts of dicyandiamide and the non-aromatic urea enhancer are 3 to 10% by weight, preferably 4 to 8% by weight, and more preferably 5 to 7% by weight, based on the total weight of the composition.

[0032] Dihydrazide represented by general formula (I) In another embodiment of the present invention, a one-component curable epoxy composition comprises the following general formula (I) as component (B): [ka] (In the formula, R is an organic group that does not contain a heterocycle.) It contains dihydrazide, represented by [the formula shown].

[0033] In a preferred embodiment of the present invention, the dihydrazide is a divalent hydrocarbon group in which R is selected from a saturated or unsaturated aliphatic hydrocarbon group having 2 to 20 carbon atoms, preferably a saturated or unsaturated linear aliphatic hydrocarbon group having 10 to 20 carbon atoms, and more preferably a saturated or unsaturated linear aliphatic hydrocarbon group having 18 carbon atoms. The saturated or unsaturated aliphatic hydrocarbon group may be substituted or unsubstituted, and is preferably unsubstituted. Preferably, the saturated or unsaturated linear aliphatic hydrocarbon group comprises simply alkyl and / or alkenyl, and more preferably alkyl and alkenyl.

[0034] In another preferred embodiment of the present invention, the dihydrazide is selected from the group consisting of 7,11-octadecadiene-1,18-dicarboxylic acid dihydrazide, sebacate acid dihydrazide, adipic acid dihydrazide, eicosanedioic acid dihydrazide, succinic acid dihydrazide, pimelic acid dihydrazide, suberic acid dihydrazide, azelaic acid dihydrazide, sebacate acid dihydrazide, dodecanediolazide, hexadecanediohydrazide, fumarate dihydrazide, tartrate dihydrazide, sebacate acid dihydrazide, adipic acid dihydrazide, and combinations thereof. Preferably, the dihydrazide is selected from the group consisting of 7,11-octadecadiene-1,18-dicarboxylic acid dihydrazide, sebacate dihydrazide, dodecane dihydrazide, adipic acid dihydrazide, and combinations thereof. More preferably, the dihydrazide is 7,11-octadecadiene-1,18-dicarboxylic acid dihydrazide, which has the following structure: [ka]

[0035] Examples of commercially available dihydrazides represented by general formula (I) include, but are not limited to, Ajinomoto Co., Inc.'s Ajicure UDH-J and Ajicure UDH, as well as sebacate dihydrazide, dodecanedihydrazide, and adipic acid dihydrazide manufactured by Otsuka Chemical Co., Ltd. Preferably, the dihydrazide represented by general formula (I) is Ajicure UDH-J and / or Ajicure UDH manufactured by Ajinomoto Co., Inc.

[0036] In a preferred embodiment of the present invention, the amount of dihydrazide represented by general formula (I) is 15 to 35% by weight, preferably 20 to 30% by weight, and more preferably 21 to 25% by weight, based on the total weight of the composition.

[0037] In a preferred embodiment of the present invention, the amounts of the non-aromatic curing agent and the optional non-aromatic accelerator (B) are 3 to 40% by weight, preferably 4 to 30% by weight, and more preferably 4 to 25% by weight, based on the total weight of the composition.

[0038] (C) UV stabilizer According to the present invention, the one-component curable epoxy composition contains (C) an ultraviolet stabilizer.

[0039] The ultraviolet stabilizer can be any conventional ultraviolet stabilizer in the art, as long as it does not adversely affect the desired technical effects of the composition of the present invention. Suitable ultraviolet stabilizers include, but are not limited to, hindered amine light stabilizers.

[0040] Examples of commercially available UV stabilizers include, but are not limited to, Thasorb UV-292 from Rianlon, as well as RIASORB UV-770, RIASORB UV-292, RIASORB UV-123, and RIASORB UV-144 from Rianlon. Preferably, the UV stabilizer is the one traded under the name Thasorb UV-292 from Rianlon.

[0041] The amount of UV stabilizer can be determined by a technical expert according to the actual conditions.

[0042] (D) Rubber with a core-shell structure According to the present invention, the one-component curable epoxy composition includes (D) a rubber having a core-shell structure used as a toughening agent.

[0043] The core-shell structured rubber used in the present invention may be any conventional rubber in the art, as long as it does not adversely affect the desired technical effects of the composition of the present invention. Examples of commercially available core-shell structured rubbers include, but are not limited to, Kane Ace B-564, Kane Ace M-731, and Kane Ace M-521, manufactured by Kaneka Corporation. Preferably, the core-shell structured rubber is the one traded as Kane Ace B-564, manufactured by Kaneka Corporation.

[0044] In a preferred embodiment of the present invention, the amount of rubber (D) having a core-shell structure is 3 to 20% by weight, preferably 4 to 18% by weight, based on the total weight of the composition.

[0045] (E) filler According to the present invention, the one-component curable epoxy composition may further contain (E) a filler.

[0046] The fillers used in the present invention may be any conventional fillers in the art, as long as they do not adversely affect the desired technical effects of the composition of the present invention. Examples of commercially available fillers include, but are not limited to, CAB-O-SIL Ts-720 fumed silica from Cabot Corporation; and FE 920 A SQ, SE5200-SEJ, and FEB25G-SED from Admatex Corporation. Preferably, the fillers used in the present invention are a combination of CAB-O-SIL Ts-720 fumed silica and FE 920 A SQ.

[0047] In a preferred embodiment of the present invention, the amount of filler (E) is 5 to 50% by weight, preferably 7 to 29% by weight, and more preferably 8 to 25% by weight, based on the total weight of the composition.

[0048] (F) Coloring agents According to the present invention, the one-component curable epoxy composition may further contain (F) a coloring agent.

[0049] The colorants used in the present invention may be any conventional colorants in the art, as long as they do not adversely affect the desired technical effects of the composition of the present invention. Examples of commercially available colorants include, but are not limited to, EHCH 15410 (white) and EHCH 87163 (black) from American Colors. Preferably, the colorant is a white color paste manufactured under the trade name EHCH 15410 by American Colors, containing a hydrogenated bisphenol A liquid epoxy resin, a non-aromatic epoxy diluent, titanium dioxide, and a dispersant.

[0050] In a preferred embodiment of the present invention, the amount of colorant (F) is 0.1 to 10.0% by weight, preferably 2.0 to 8.0% by weight, and more preferably 3.0 to 7.0% by weight, based on the total weight of the composition.

[0051] (G) Non-aromatic epoxy diluent According to the present invention, the one-component curable epoxy composition may further contain a non-aromatic epoxy diluent.

[0052] The non-aromatic epoxy diluent used in the present invention may be a conventional non-aromatic epoxy diluent in the art, provided that it does not adversely affect the desired technical effects of the composition of the present invention. Preferably, the non-aromatic epoxy diluent is a diglycidyl ether diluent. More preferably, the non-aromatic epoxy diluent is selected from the group consisting of 1,4-cyclohexanedimethanol diglycidyl ether, polyethylene glycol diglycidyl ether, poly(2-hydroxypropylene) glycol diglycidyl ether, polypropylene glycol diglycidyl ether, 1,3-bis(3-glycidoxypropyl)-1,1,3,3-tetramethyldisiloxane, and combinations thereof. Most preferably, the non-aromatic epoxy diluent is 1,4-cyclohexanedimethanol diglycidyl ether.

[0053] Examples of commercially available non-aromatic epoxy diluents include, but are not limited to, KF EPIOL-LD204 from KUKDO FINECHEM, jER YED216D from Mitsubishi Chemical Corporation, and PG-207GS and ZX-1658GS from Nippon Steel Corporation. Preferably, the commercially available non-aromatic epoxy diluent is selected from the group consisting of EPIOL-LD204 from KUKDO FINECHEM, ZX-1658GS from Nippon Steel Corporation, and combinations thereof. More preferably, the commercially available non-aromatic epoxy diluent is EPIOL-LD204 from KUKDO FINECHEM.

[0054] In a preferred embodiment of the present invention, the amount of non-aromatic epoxy diluent (G) is 5 to 30% by weight, preferably 10 to 25% by weight, and more preferably 15 to 22% by weight, based on the total weight of the composition.

[0055] In a preferred embodiment of the present invention, the one-component curable epoxy composition does not contain an aromatic epoxy diluent.

[0056] (H) Coupling agent According to the present invention, the one-component curable epoxy composition may further contain a (H) coupling agent.

[0057] The coupling agent used in the present invention may be any conventional coupling agent in the art, as long as it does not adversely affect the desired technical effects of the composition of the present invention. Preferably, the coupling agent is an epoxy-functionalized silane. Examples of commercially available coupling agents include, but are not limited to, Silkquest A-187 and Silkquest A-186 from Momentive Performance Materials. Preferably, the coupling agent is the one traded as Silkquest A-187 from Momentive Performance Materials.

[0058] In a preferred embodiment, the amount of the coupling agent is 0.1 to 5% by weight, preferably 0.3 to 3% by weight, based on the total weight of the composition.

[0059] In some embodiments of the present invention, the one-component curable epoxy composition may further optionally contain additives commonly used in the art to which the present invention belongs, such as flame retardants (e.g., ATH (aluminum trihydrate) or phosphate ester flame retardants), thermal conductivity enhancers (e.g., boron nitride), thixotropic agents, or combinations thereof, provided that they do not adversely affect the desired technical effects of the composition of the present invention. The presence, type, and amount of additives may be determined by experts in the art according to actual requirements.

[0060] A preferred embodiment of the present invention, the one-component curable epoxy composition of the present invention, includes the following: (A) 55 to 85% by weight, preferably 57 to 80% by weight, of each non-aromatic epoxy resin based on the total weight of the composition; (B) A combination of dicyandiamide and a non-aromatic urea enhancer in an amount of 3 to 10% by weight, preferably 4 to 8% by weight, based on the total weight of the composition; (C) UV stabilizer; (D) Rubber having a core-shell structure; and (E) Optionally, 5 to 20% by weight, preferably 7 to 15% by weight, of fillers based on the total weight of the composition.

[0061] Another preferred embodiment of the present invention, the one-component curable epoxy composition of the present invention, includes: (A) 20 to 55% by weight, preferably 42 to 50% by weight, of each non-aromatic epoxy resin based on the total weight of the composition; (B) Dihydrazides represented by the general formula (I) as defined above, in an amount of 15 to 35% by weight, preferably 20 to 30% by weight, based on the total weight of the composition; (C) UV stabilizer; (D) Rubber having a core-shell structure; and (E) Optionally, 17 to 30% by weight, preferably 20 to 25% by weight, of fillers based on the total weight of the composition.

[0062] The one-component curable epoxy composition of the present invention can be prepared by any conventional preparation method in the art. In particular, the composition can be prepared by a method comprising the following steps: (1) mixing all components except the curing agent and any curing accelerator by mechanical stirring; and (2) adding the curing agent and any curing accelerator to the mixture obtained in step (1), and further mixing the mixture by mechanical stirring to obtain a homogeneous composition.

[0063] The one-component curable epoxy composition of the present invention can be used for bonding substrates together, and this bonding includes the steps of applying the one-component curable epoxy composition of the present invention to a first substrate, bringing the first substrate coated with the composition into contact with the second substrate, bringing a second substrate into contact with the first substrate coated with the one-component curable epoxy composition of the present invention, and subjecting the coated composition to conditions under which the coated composition can be cured. The one-component curable epoxy composition can be applied by any conventional method in the art, such as dispensing, injecting, spraying, flow coating, blade coating, brush coating, pouring, dipping, impregnation, dropping, roller coating, sprinkle coating, and dipping coating. Preferably, the one-component curable epoxy composition is applied by dispensing or injecting. In the present invention, the substrate can be made from metal, glass, resin composite materials, and ceramics, and preferably the substrate can be made from metal. To cure the epoxy, the one-component curable epoxy composition may be heated at 120-180°C for 10-150 minutes, preferably at 130°C for 120 minutes or at 150°C for 60 minutes.

[0064] In a second embodiment, the disclosure relates to a cured product of the one-component curable epoxy composition of the present invention, an article containing the cured product, and the use of the one-component curable epoxy composition or its cured product in an electronic device.

[0065] The one-component curable epoxy composition of the present invention can be used for bonding metal structures where appearance is important, has anodization resistance and Q-sun resistance, and can be color-matched. Preferably, the one-component curable epoxy composition can be used for electronic devices, preferably including exterior parts to which metal structures are bonded, particularly for gap filling in watch housings, antenna division in phones and tablets, and headphone antenna slots.

[0066] The one-component curable epoxy composition of the present invention exhibits both color stability and good adhesion upon curing, particularly a combination of low color change after Q-sun testing, low color change after metal anodizing, and strong adhesion to metals. Specifically, the composition demonstrates a combination of ΔE94 color change ≤ 3 after Q-sun testing at 150 and 250 hours at 2.5 W, ΔE94 color change ≤ 3 after pickling in metal anodizing, Ti-to-Ti lap shear strength ≥ 20 MPa, and AnAl (anodic aluminum oxide)-to-AnAl lap shear strength ≥ 20 MPa. [Examples]

[0067] The following examples are intended to help those skilled in the art to better understand and implement the present invention. The scope of the present invention is not limited by the examples but is defined by the appended claims. Unless otherwise specified, parts and percentages are all based on weight.

[0068] raw material Ingredient (A) Component a-1: JER YX-8000D, non-aromatic epoxy resin (hydrogenated bisphenol A), with an epoxy equivalent of 180-200 g / mol, available from Mitsubishi Chemical Corporation. Component a-2': EPON Resin 828, aromatic epoxy resin (bisphenol A), with an epoxy equivalent of 188 g / mol, available from Hexion.

[0069] Ingredient (B) Component b-1: Omicure DDA5, dicyandiamide curing agent, particle size ≤10 microns, available from Huntsman. Component b-2: Omicure U 35M, a non-aromatic urea accelerator, with a particle size of ≤10 microns, available from Huntsman. Component b-3: Ajicure UDH-J, formula below: [ka] A dihydrazide hardening agent, represented by [formula], is available from Ajinomoto Co., Inc. Component b-4': Ajicure VDH-J, formula below: [ka] A dihydrazide hardening agent, represented by [formula], is available from Ajinomoto Co., Inc. Component b-5: Ajicure UDH, formula below: [ka] A dihydrazide hardening agent, represented by [formula], is available from Ajinomoto Co., Inc.

[0070] Ingredients (C) Ingredient c-1: Thasorb UV-292, UV stabilizer, available from Rianlon.

[0071] Ingredients (D) Component d-1: Kane Ace B-564, a rubber with a core-shell structure, available from Kaneka Corporation.

[0072] Ingredient (E) Component e-1: CAB-O-SIL Ts-720 fumed silica, filler, available from Cabot Corporation. Component e-2: Fe-920 A SQ, filler, available from Admatex Co., Ltd.

[0073] Ingredient (F): Component f-1: EHCH 15410, white color paste (containing hydrogenated bisphenol A liquid epoxy resin, non-aromatic epoxy diluent, titanium dioxide, and dispersant), available from American Colors.

[0074] Ingredients (G) Component g-1: KF EPIOL LD-204, a non-aromatic epoxy diluent, with an epoxy equivalent of 150 g / mol, available from KUKDO FINECHEM. Component g-2': ERISYS RDGE, aromatic epoxy diluent, with an epoxy equivalent of 121 g / mol, available from Huntsman. Component g-3: YED-216 D, an aliphatic epoxy diluent, with an epoxy equivalent of 120 g / mol, available from Mitsubishi Chemical Corporation.

[0075] Ingredients (H) Component h-1: SILQUEST A-187 silane, coupling agent, available from Momentive.

[0076] Examples 1-9 (Ex.1-Ex.9) and Comparative Examples 1-8 (CEx.1-CEx.8) Tables 1 to 3 show the specific amounts and types of components in the one-component curable epoxy compositions of Examples 1 to 9 and Comparative Examples 1 to 8 of the present invention. The compositions were prepared as follows: (1) All components except the curing agent and any curing accelerator were mixed for 3 minutes at 1600 rpm using a FlackTek SpeedMixer DAC 1200-300 VAC; and (2) The curing agent and any curing accelerator were added to the mixture obtained in step (1), and this mixture was further mixed for 3 minutes at 1600 rpm and 5 mbar using a DAC 1200-300 VAC to obtain a homogeneous composition.

[0077] Test method: Preparation of color paste: The compositions obtained in Examples 1-9 and Comparative Examples 1-8 were premixed in a speed mixer, degassed in a vacuum to form a premixture to be cured, and then poured into a polyoxymethylene mold with dimensions of 3 mm thickness × 75 mm length × 50 mm width, and cured in an oven at 115°C for 3 hours.

[0078] Color change test method: The plate color obtained above was measured according to ASTM E1347-06 (2020). The initial plate color was measured using a Konica Minolta CM3700 A spectrophotometer in reflectance specular component (SCI) mode at an observer angle of 10 degrees. The following Q-sun test and Pickling test simulationAfter the process, the color of the plates was measured using the exact same method as described above. The difference in color before and after the Q-sun test and pickling test simulation process was calculated using the ΔE94 calculation specified by the International Commission on Illumination (CIE), under an illuminance of F02 (cool white fluorescent lamp) and a 1:C ratio of 2:1.

[0079] Q-sun test The plates obtained from the compositions of Examples 1-9 and Comparative Examples 1-8 were subjected to Q-Sun tests for 150 hours and 250 hours, respectively, under the following conditions, in accordance with ASTM D4459: Equipment: ATLAS Ci3000 + Weatherometer Irradiation intensity: 2.5W / (M2·nm) Chamber temperature 35℃ Relative humidity: 30% Black panel temperature: 55℃ Xenon lamp tube output: 3.57kW

[0080] The ΔE94 color change ≤ 3 after 2.5W, 150 hours, and 250 hours of Q-sun testing is within the acceptable range.

[0081] Pickling Test Simulation Process The pickling was carried out according to the anodizing treatment of aluminum electronic devices described in U.S. Patent Application Publication No. 2013 / 0270120. The treatment steps that have the greatest impact on the color are desmutting (smut removal) and chemical polishing. A desmutting bath was prepared with 30% nitric acid. A chemical polishing bath was prepared by mixing concentrated sulfuric acid (98%) and 85% phosphoric acid in a weight ratio of 1:3.

[0082] Specifically, the pickling test was simulated using the following procedure: TIFF2026516530000012.tif48165

[0083] A ΔE94 color change of ≤ 3 after pickling in metal anodizing is acceptable.

[0084] Ti vs. Ti lap shear strength, and AnAl vs. AnAl lap shear strength The lap shear strength of the composition was measured using an INSTRON 5900 in accordance with the ASTM D1002-10 (2019) standard, with a maximum load of 30 KN and a tensile speed of 10 mm / min.

[0085] Base material form and size: Titanium alloy TC4, 101.6mm × 25.4mm × 2mm; Anodized aluminum 6063, 101.6mm × 25.4mm × 2mm Bonding area and thickness: 25.4mm x 12.7mm x 0.127mm Curing conditions: 150℃ x 1 hour Number of samples per composition: The results shown in the table below are the average values ​​of 5 samples.

[0086] Before preparing the sample, the surface of the substrate must be wiped with a dust-free cloth soaked in ethanol.

[0087] A lap shear strength of ≥20 MPa for Ti-to-Ti and ≥20 MPa for AnAl-to-AnAl is within the acceptable range.

[0088] The color change and wrap shear strength of the composition were tested using the methods described above, and the results are shown in Tables 1 to 3 below.

[0089] [Table 1]

[0090] [Table 2]

[0091] From the data in Tables 1 and 2, it can be seen that the one-component curable epoxy compositions of the present invention (Examples 1 to 5), containing combinations of components (A) to (D), exhibited both color stability and good adhesion upon curing, particularly a combination of low color change after Q-sun testing, low color change after metal anodizing, and strong adhesion to metals. Specifically, the compositions demonstrated a combination of ΔE94 color change ≤ 3 after Q-sun testing at 150 and 250 hours at 2.5 W, ΔE94 color change ≤ 3 after pickling in metal anodizing, Ti-to-Ti lap shear strength ≥ 20 MPa, and AnAl (anodic aluminum oxide)-to-AnAl lap shear strength ≥ 20 MPa.

[0092] In contrast, epoxy compositions that do not conform to the present invention (Comparative Examples 1 to 9) did not exhibit a combination of low color change after Q-sun testing, low color change after metal anodizing, and strong adhesion to metal. For example, in contrast to Example 3, Comparative Examples 1 and 2 (neither containing non-aromatic epoxy resins) both showed a much higher ΔE94 color change and a lower lap shear strength than 3 (both containing a heterocyclic dihydrazide). Comparative Example 3 (without rubber having a core-shell structure) also showed a much higher ΔE94 color change and a lower lap shear strength than 3 (both containing a heterocyclic dihydrazide). Furthermore, in contrast to Example 5, Comparative Examples 4 and 5 (neither containing non-aromatic epoxy resins) both showed a much higher ΔE94 color change than 3 (both containing a heterocyclic dihydrazide). Comparative Example 6 (without a non-aromatic epoxy resin, containing a heterocyclic dihydrazide) showed a lower lap shear strength than 20 MPa. Comparative Examples 7 and 8 (both containing a heterocyclic dihydrazide) both showed a lower lap shear strength than 20 MPa.

[0093] [Table 3]

[0094] From the data in Table 3, it can be seen that the one-component curable epoxy compositions of the present invention (Examples 6 to 9), which contain combinations of components (A) to (D) together with a colorant, also exhibited both color stability and good adhesion after curing.

[0095] While several preferred embodiments have been described, many modifications and variations are possible in light of the above teachings. Therefore, it should be understood that the present invention can be implemented in ways other than those specifically described without departing from the scope of the appended claims.

Claims

1. A one-component curable epoxy composition containing the following: (A) 20 to 90% by weight of a non-aromatic epoxy resin based on the total weight of the composition; (B) Non-aromatic curing agents and optionally non-aromatic accelerators which are a combination of dicyandiamide and a non-aromatic urea accelerator, or the following general formula (I): 【Chemistry 1】 Dihydrazides represented by the formula (wherein R is an organic group that does not contain a heterocycle); (C) UV stabilizers; and (D) Rubber having a core-shell structure.

2. (E) The one-component curable epoxy composition according to claim 1, further comprising a filler.

3. The one-component curable epoxy composition according to claim 2, wherein the amount of filler (E) is 5 to 50% by weight, preferably 7 to 29% by weight, and more preferably 8 to 25% by weight, based on the total weight of the composition.

4. (F) The one-component curable epoxy composition according to claim 1, further comprising a coloring agent.

5. The one-component curable epoxy composition according to claim 4, wherein the amount of the coloring agent (F) is 0.1 to 10.0% by weight, preferably 2.0 to 8.0% by weight, and more preferably 3.0 to 7.0% by weight, based on the total weight of the composition.

6. (G) The one-component curable epoxy composition according to claim 1, further comprising a non-aromatic epoxy diluent.

7. The one-component curable epoxy composition according to claim 1, wherein the amount of the non-aromatic curing agent and optionally the non-aromatic accelerator (B) is 3 to 40% by weight, preferably 4 to 30% by weight, and more preferably 4 to 25% by weight, based on the total weight of the composition.

8. The one-component curable epoxy composition according to claim 1, wherein R is a divalent hydrocarbon group selected from a saturated or unsaturated aliphatic hydrocarbon group having 2 to 20 carbon atoms, preferably a saturated or unsaturated linear aliphatic hydrocarbon group having 10 to 20 carbon atoms, in the dihydrazide represented by the following general formula (I).

9. The one-component curable epoxy composition according to claim 1, wherein the amount of the non-aromatic epoxy resin (A) is 30 to 90% by weight, preferably 42 to 85% by weight, and more preferably 42 to 80% by weight, based on the total weight of the composition.

10. A one-component curable epoxy composition according to any one of claims 1 to 9, comprising the following: (A) 55 to 85% by weight, preferably 57 to 80% by weight, of a non-aromatic epoxy resin based on the total weight of the composition; (B) A combination of dicyandiamide and a non-aromatic urea promoter in an amount of 3 to 10% by weight, preferably 4 to 8% by weight, based on the total weight of the composition; (C) UV stabilizer; (D) Rubber having a core-shell structure; and (E) Optionally, 5 to 20% by weight, preferably 7 to 15% by weight, of filler based on the total weight of the composition.

11. A one-component curable epoxy composition according to any one of claims 1 to 9, comprising the following: (A) 20 to 55% by weight, preferably 42 to 50% by weight, of a non-aromatic epoxy resin based on the total weight of the composition; (B) 15 to 35% by weight, preferably 20 to 30% by weight, of a dihydrazide represented by general formula (I) as defined in claim 1 or 8, based on the total weight of the composition; (C) UV stabilizer; (D) Rubber having a core-shell structure; and (E) Optionally, 17 to 30% by weight, preferably 20 to 25% by weight, of filler based on the total weight of the composition.

12. A one-component curable epoxy composition according to any one of claims 1 to 9, further comprising a (H) coupling agent, preferably an epoxy-functionalized silane.

13. A cured product of a one-component curable epoxy composition according to any one of claims 1 to 9.

14. An article comprising the cured product described in claim 13.

15. A one-component curable epoxy composition according to any one of claims 1 to 9, for use in electronic devices, preferably including exterior parts to which metal structures are bonded, particularly in gap filling of watch housings, telephone and tablet antenna splits, and headphone antenna slots.

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