Two-component curable adhesive composition

Abstract

Provided is a two-part curing adhesive composition comprising: Component A, which comprises: (a) at least one alkyl (meth)acrylate monomer; (b) at least one acrylonitrile-butadiene rubber having an acrylonitrile content of less than 45 wt. %, based on the total weight of the acrylonitrile-butadiene rubber; and (c) at least one flexibilizer selected from polyester-based urethane (meth)acrylate oligomers and / or (meth)acrylate-terminated acrylonitrile-butadiene oligomers; and Component B, which comprises at least one catalyst.

Description

[Technical Field]

[0001] The present invention relates to a two-part curable adhesive composition and its use. [Background technology]

[0002] Structural adhesives have been widely used in manufacturing environments to bond substrates such as metals and plastics due to their fast cure rate and high impact resistance. Generally, structural adhesives are formed from two components: a composition containing a curing agent (based on acrylates or methacrylates) and a catalyst for curing the adhesive. These two components are stored in two separate compartments and mixed before applying the adhesive. The catalyst is based on a free-radical polymerization initiator, particularly a peroxide, and is well known in the art. The curing agent component may also contain other elements, such as a cure accelerator, rheology modifier, or adhesion promoter. Such adhesives are described, inter alia, in US 2013 / 0292054 A1, US 6602958 B2, and EP 2194105 B1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2013 / 0292054 [Patent Document 2] U.S. Patent No. 6,602,958 [Patent Document 3] European Patent No. 2194105 Summary of the Invention [Problem to be solved by the invention]

[0004] When structural adhesives are used in portable electronic devices, they may come into contact with human skin and be exposed to chemicals such as sweat, oils, and cosmetics, which can degrade the adhesive's properties. Little prior art has been found to improve the chemical resistance of structural adhesives. Therefore, there is a need for a two-part curing adhesive composition that exhibits excellent chemical resistance, such as oleic acid resistance, upon curing while maintaining mechanical properties and dispensability. [Means for solving the problem]

[0005] In accordance with a first aspect of the present invention, disclosed herein is a two-part curable adhesive composition comprising: (a) at least one alkyl (meth)acrylate monomer; (b) at least one acrylonitrile-butadiene rubber having an acrylonitrile content of less than 45% by weight, based on the total weight of the acrylonitrile-butadiene rubber; and (c) at least one flexibilizing agent selected from polyester-based urethane (meth)acrylate oligomers and / or (meth)acrylate-terminated acrylonitrile-butadiene oligomers; Component A comprising: Component B, which comprises at least one catalyst.

[0006] In accordance with a second aspect of the present invention, provided herein is a method for preparing a two-part curable adhesive composition.

[0007] According to a third aspect of the present invention, provided herein is a laminate comprising a first substrate, a second substrate, and an adhesive layer sandwiched therebetween, wherein the first substrate and the second substrate are independently selected from glass, resin, and metal, and the adhesive layer is formed by curing an adhesive composition of the present invention.

[0008] According to a fourth aspect of the present invention, provided herein is an electronic device comprising the laminate of the present invention or manufactured using the adhesive composition according to the present invention.

[0009] According to a fifth aspect of the present invention, provided herein is the use of an adhesive composition according to the present invention or a laminate according to the present invention in the manufacture of an electronic device.

[0010] Other features and aspects of the subject matter are described in further detail below. DETAILED DESCRIPTION OF THE INVENTION

[0011] Those skilled in the art will appreciate that the present invention has been described with reference to exemplary embodiments only, and is not intended to limit the broad aspects of the present invention. Each aspect so described may be combined with other aspects unless expressly indicated to the contrary. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature indicated as being preferred or advantageous.

[0012] Unless otherwise specified, in the context of the present invention, the terms used shall be construed in accordance with the following definitions.

[0013] Unless otherwise specified, as used herein, the terms "a," "an," and "the" include both singular and plural references.

[0014] As used herein, the terms "comprising" and "comprises" are synonymous with "including," "includes," "containing," or "contains," and are inclusive or open-ended and do not exclude additional, unrecited members, elements, or method steps.

[0015] The terms "at least one" or "one or more" used herein to define a component refer to the type of component and not to the absolute number of molecules.

[0016] As used herein, the term "copolymer" refers to a polymer having multiple monomer units.

[0017] As used herein, the term "oligomer" refers to a low molecular weight polymer containing 10 to 100 repeating units.

[0018] As used herein, the term "graft polymer" refers to a polymer comprising molecules in which one or more block species are attached as side chains to a main chain, the side chains having structural or conformational characteristics different from those of the main chain.

[0019] In this specification, "room temperature" refers to about 15°C to about 35°C, preferably about 25°C.

[0020] Unless otherwise specified, the recitation of numerical endpoints includes all values ​​and fractions subsumed within the respective range, as well as the recited endpoint.

[0021] All documents cited herein are incorporated by reference in their entirety.

[0022] Unless otherwise stated, molecular weights refer to weight average molecular weights (Mw). All molecular weight data are determined by gel permeation chromatography (GPC) (e.g., according to DIN 55672) unless otherwise stated.

[0023] In the present context, the glass transition temperature (Tg) or melting point of a particular polymer is determined using DSC in accordance with DIN 53 765.

[0024] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the meaning commonly understood by one of ordinary skill in the art to which this invention belongs.

[0025] In one aspect, the present disclosure is generally directed to a two-part curable adhesive composition comprising: (a) at least one alkyl (meth)acrylate monomer; (b) at least one acrylonitrile-butadiene rubber having an acrylonitrile content of less than 45% by weight, based on the total weight of the acrylonitrile-butadiene rubber; and (c) at least one flexibilizing agent selected from polyester-based urethane (meth)acrylate oligomers and / or (meth)acrylate-terminated acrylonitrile-butadiene oligomers; Component A comprising: Component B, which comprises at least one catalyst.

[0026] <Ingredient A> (a) Alkyl (meth)acrylate monomer According to the present invention, component A comprises at least one alkyl (meth)acrylate monomer.

[0027] The alkyl (meth)acrylate ester monomer of Component A may be an alkyl ester of acrylic acid or methacrylic acid known in the art. For example, esters of C1-C6 monofunctional alcohols with (meth)acrylic acid (e.g., methyl acrylate, methyl methacrylate, ethyl acrylate or methacrylate, n-propyl or isopropyl acrylate or methacrylate, butyl (meth)acrylate (all isomers)), and hexyl (meth)acrylate, esters of high molecular weight alcohols having up to 12 carbon atoms (e.g., lauryl (meth)acrylate, 2-ethylhexyl (meth)acrylate, hexyl (meth)acrylate, isodecyl (meth)acrylate, etc.). Component A may also contain a combination of two or more such monomers. Preferred alkyl (meth)acrylate monomers are esters of C1-C4 monofunctional alcohols with (meth)acrylic acid, with methacrylic acid esters being particularly preferred. Methyl methacrylate is particularly preferred.

[0028] Suitable commercially available components (a) include methyl methacrylate from Lucite International, VISIOMER® MMA from Evonik, and methyl methacrylate from Mitsubishi Chemical.

[0029] Particularly preferably, the alkyl (meth)acrylate monomer (a) may be present in an amount of 40 to 85% by weight, preferably 40 to 70% by weight, based on the total weight of the adhesive composition.

[0030] (b) acrylonitrile-butadiene rubber According to the invention, component A comprises at least one acrylonitrile-butadiene rubber having an acrylonitrile content of less than 45% by weight, based on the total weight of the acrylonitrile-butadiene rubber.

[0031] The term acrylonitrile-butadiene rubber (also known as nitrile rubber, also abbreviated as "NBR") in the context of this application is understood to mean a rubber which is a copolymer, terpolymer or quaterpolymer of at least one α,β-ethylenically unsaturated nitrile, at least one conjugated diene, and optionally one or more additional copolymerizable monomers. Generally, the weight average molecular weight (Mw) of NBR is in the order of 700,000 g / mol or more.

[0032] Preferably, the acrylonitrile-butadiene rubber has an acrylonitrile content of 10 to 42% by weight, preferably 20 to 40% by weight, and more preferably 30 to 40% by weight, based on the total weight of the acrylonitrile-butadiene rubber. The higher the acrylonitrile content in the acrylonitrile-butadiene rubber, the higher the oil resistance of the material but the lower its flexibility. By using this specific range, the two-component curing adhesive composition has a good balance of chemical resistance and fluidity.

[0033] Functionalized acrylonitrile-butadiene rubber is a copolymer that has been chemically modified to include one or more functional groups, such as hydroxyl groups, amino groups, ether groups, ester groups, amide groups, sulfonate groups, sulfonic acid groups, carboxyl groups, and carboxylate groups, and can also be used as component (b). The presence of functional groups on the acrylonitrile-butadiene rubber promotes crosslinking. In one embodiment, the functionalized acrylonitrile-butadiene rubber contains one or more functional groups covalently bonded to the backbone of the copolymer, either directly or through a moiety such as an alkyl group.

[0034] Derivatives of NBR include carboxylated NBR (XNBR), carboxylated hydrogenated NBR (XHNBR), and NBR in which some of the nitrile groups have been replaced with amide groups (referred to as amidated NBR or ANBR), or a combination comprising at least one of the foregoing.

[0035] In some embodiments, the acrylonitrile-butadiene rubber (b) has a glass transition temperature (Tg) of -15 to -45°C, preferably -30 to -35°C.

[0036] Suitable acrylonitrile-butadiene rubbers for component (b) can be prepared by free radical copolymerization of butadiene and acrylonitrile in emulsion.

[0037] Commercially available acrylonitrile butadiene rubbers include Nipol® DN401L, DN2850, 1052, and 4050 from Zeon Chemicals.

[0038] Particularly preferably, the acrylonitrile-butadiene rubber may be present in an amount of 0.1 to 30% by weight, preferably 5 to 25% by weight, based on the total weight of the adhesive composition.

[0039] (c) Flexibilizer According to the present invention, component A comprises at least one flexibilizer selected from polyester-based urethane (meth)acrylate oligomers and / or (meth)acrylate-terminated acrylonitrile-butadiene oligomers.

[0040] In some embodiments, a polyester-based urethane (meth)acrylate oligomer is used as a flexibilizer in component A of the adhesive composition. The polyester-based urethane (meth)acrylate oligomer may be selected from monofunctional polyester-based urethane (meth)acrylate oligomers and / or multifunctional polyester-based urethane (meth)acrylate oligomers, preferably difunctional polyester-based urethane acrylate oligomers.

[0041] The polyester-based urethane (meth)acrylate oligomer may have a weight average molecular weight (Mw) of 10,000 to less than 40,000 g / mol.

[0042] In some embodiments, polyester-based urethane (meth)acrylate oligomers can be obtained by reacting an aliphatic or aromatic isocyanate having two or more isocyanate groups per molecule with a polyester polyol, and then subjecting the remaining unreacted isocyanate groups to an addition reaction with a hydroxyl group-containing (meth)acrylate monomer. The polyester polyol used to prepare the polyester-based urethane (meth)acrylate oligomers can be selected from polyethylene adipate diol, polybutylene adipate diol, polyhexamethylene isophthalate adipate diol, 3-methyl-1,5-pentane isophthalate diol, 3-methyl-1,5-pentane terephthalate diol, and polycondensates of 1,6-hexanediol and dimer acid. Aliphatic or aromatic isocyanates having two or more isocyanate groups per molecule used in the preparation of polyester-based urethane acrylate oligomers include aliphatic isocyanate compounds including isophorone diisocyanate, dicyclohexylmethane-4,4-diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexane diisocyanate, butene diisocyanate, 1,3-butadiene-1,4-diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, 1,6,11-undecatriisocyanate, etc.; and bis(isocyanatoethyl)benzene, bis(isocyanatopropyl ... The isocyanate may be selected from bis(isocyanatobutyl)benzene, bis(isocyanatomethyl)naphthalene, bis(isocyanatomethyl)diphenyl ether, phenylene diisocyanate, ethylphenylene diisocyanate, isopropylphenylene diisocyanate, dimethylphenylene diisocyanate, diisopropylphenylene diisocyanate, trimethylbenzene triisocyanate, benzene triisocyanate, biphenyl diisocyanate, 3,3-dimethoxybiphenyl-4,4-diisocyanate, hexahydrobenzene diisocyanate, hexahydrodiphenylmethane-4,4-diisocyanate, and mixtures thereof.The hydroxyl group-containing (meth)acrylate monomer used in the preparation of the polyester-based urethane acrylate oligomer may be selected from 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 1-chloro-2-hydroxypropyl (meth)acrylate, diethylene glycol mono(meth)acrylate, 1,6-hexanediol mono(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, and combinations thereof.

[0043] Suitable commercially available polyester-based urethane (meth)acrylate oligomers are sold by BOMAR Specialties LLC as BR-7432GB and BR-741, by RAHN as GENOMER 3485 and GENOMER 3611, and by Nippon Kayaku as UX-3204 and UXT-6000.

[0044] Alternatively, (meth)acrylate-terminated acrylonitrile-butadiene oligomers may also be used as flexibilizers in component A of the adhesive composition to achieve the desired effect. (Meth)acrylate-terminated acrylonitrile-butadiene oligomers refer to (meth)acrylate groups at both ends of an acrylonitrile-butadiene copolymer backbone.

[0045] The acrylonitrile content of the (meth)acrylate-terminated acrylonitrile-butadiene oligomer used in the present invention is not particularly limited, and may be, for example, 5 to 60% of the acrylonitrile content based on the total weight of the (meth)acrylate-terminated acrylonitrile-butadiene oligomer.

[0046] In a preferred embodiment, the (meth)acrylate terminated acrylonitrile-butadiene oligomer may have a weight average molecular weight (Mw) of less than 200,000 g / mol, more preferably from 3000 to 10000 g / mol.

[0047] In a preferred embodiment, the (meth)acrylate terminated acrylonitrile-butadiene oligomer may have a viscosity of 50,000 cps to 1,000,000 cps at ambient temperature.

[0048] Suitable commercially available (meth)acrylate terminated acrylonitrile-butadiene oligomers are sold by Huntsman as Hypro® 1300X33LC VTBNX and Hypro® 1300X43LC VTBNX.

[0049] In some embodiments, a combination of a polyester-based (meth)urethane acrylate oligomer and a (meth)acrylate-terminated acrylonitrile-butadiene oligomer may be used as the flexibilizer in component A of the adhesive composition.

[0050] Particularly preferably, the flexibilizer (c) may be present in an amount of 0.1 to 20% by weight, preferably 5 to 15% by weight, based on the total weight of the adhesive composition.

[0051] (d) A core-shell graft polymer other than component (b). According to the present invention, component A optionally comprises at least one core-shell graft polymer other than component (b). Generally, component (d), if present, is non-reactive in the composition and is used to adjust viscosity and provide toughness to the adhesive composition upon cure.

[0052] The core-shell graft polymer of component (d) can be any of those well known to those skilled in the art. These materials are particulate graft copolymers with a rubbery or elastomeric core and a hard shell. They swell but do not dissolve in alkyl (meth)acrylate monomer (a). Typically, so-called "hard" monomers (e.g., styrene, acrylonitrile, or methyl methacrylate) are grafted onto a rubbery core made from a polymer of so-called "soft" monomers (e.g., butadiene or ethyl acrylate). The "core" or backbone polymer of the graft polymer has a glass transition temperature significantly lower than ambient temperature. The "shell" polymer grafted onto the backbone polymer has a glass transition temperature significantly higher than ambient temperature. Ambient temperature is defined as the temperature range in which the adhesive composition is used.

[0053] Core-shell polymers are often referred to by the abbreviations of the monomers they contain, and useful types include methacrylate-butadiene-styrene (MBS) graft copolymer, styrene-butadiene-styrene (SBS) graft copolymer, acrylate-styrene-acrylic acid (ASA) graft copolymer, acrylonitrile-butadiene-styrene graft copolymer (ABS), and combinations thereof.

[0054] Preferably, the core-shell graft polymer comprises a shell derived from a methacrylate polymer or methacrylate copolymer, with MBS-type core-shell graft polymers being preferred.

[0055] Suitable commercially available core-shell graft polymers are sold as KANE ACE® FM50 by KANEKA BELGIUM NV, KANE ACE® M-521 and KANE ACE® B-564 by KANEKA, and S-2030 and C-223A by Mitsubishi Chemical.

[0056] Particularly preferably, the core-shell graft polymer (d) may be present in an amount of 0.1 to 30% by weight, preferably 5 to 20% by weight, based on the total weight of the adhesive composition.

[0057] additives Component A may optionally include at least one additive selected from adhesion promoters, inhibitors, chelating agents, reducing agents, thixotropic agents, and combinations thereof.

[0058] Adhesion promoters can enhance the adhesion of the composition to the substrate. Suitable examples include organic acids, carboxylic acids, and methacrylated phosphate esters. Exemplary carboxylic acids include methacrylic acid, maleic acid, acrylic acid, fumaric acid, malonic acid, and combinations thereof. Exemplary methacrylated phosphate esters include 2-hydroxyethyl methacrylate phosphate, phosphate ester of polyethylene glycol monomethacrylate, ethyl methacrylate phosphate, and combinations thereof. A commercially available adhesion promoter is available from Harcros Chemicals as Harcryl 1228. When present, the adhesion promoter may be present in an amount of 0.1 to 15 wt %, more preferably 0.1 to 10 wt %, based on the total weight of the adhesive composition.

[0059] The reducing agent may enhance the catalyst. Suitable examples may be selected from tertiary amines and aldehyde-amine reaction products. Useful tertiary amines include N,N-dimethylaniline, N,N-dimethyltoluidine, N,N-dimethylaniline, p-tolyldiethanolamine, and combinations thereof. Commercially available reducing agents, such as N,N-dimethyl-p-toluidine, are available from RSA Corporation. When present, the reducing agent may be present in an amount of 0.5 to 5 wt. %, more preferably 1 to 2 wt. %, based on the total weight of the adhesive composition.

[0060] The inhibitor can extend the shelf life of the adhesive composition and provide a desirable working time. Suitable examples include hydroquinone, methylhydroquinone, paranaphthoquinone, and combinations thereof. Commercially available inhibitors, such as methylhydroquinone, are available from Sigma-Aldrich. When present, the inhibitor may be present in an amount of 0.01 to 1 wt. % based on the total weight of the adhesive composition, more preferably 0.01 to 0.1 wt. %.

[0061] Thixotropic agents can be used to modify the viscosity of the adhesive composition. A suitable thixotropic agent is fumed silica. A commercially available product of fumed silica is Aerosil 200 from Evonik. When present, the thixotropic agent may be present in an amount of 0.1 to 5 wt. %, more preferably 0.1 to 2 wt. %, based on the total weight of the adhesive composition.

[0062] Chelating agents can be used to chelate metal ions in the adhesive, prevent premature curing, and improve storage stability. A suitable chelating agent can be ethylenediaminetetraacetic acid (EDTA). A commercially available chelating agent is Versene 220 from Dow. When present, the chelating agent can be present in an amount of 0.01 to 1 wt. %, more preferably 0.01 to 0.5 wt. %, based on the total weight of the adhesive composition.

[0063] Component B Catalyst According to the present invention, component B comprises at least one catalyst suitable for promoting the curing and / or crosslinking of component A.

[0064] Suitable catalysts for use in the present invention include benzoyl peroxide, cumene hydroperoxide, tertiary butyl hydroperoxide, dicumyl peroxide, tertiary butyl peroxide acetate, tertiary butyl perbenzoate, ditertiary butyl azodiisobutyronitrile, and combinations thereof.

[0065] Particularly preferably, the catalyst may be present in an amount of 0.1 to 20% by weight, preferably 1 to 10% by weight, based on the total weight of the adhesive composition.

[0066] adhesive composition The mixing ratio of component A to component B is 1:1 to 20:1 by weight, preferably 4:1 to 10:1.

[0067] In certain preferred embodiments, the two-part curing adhesive composition comprises, based on the total weight of the adhesive composition: 40 to 85% by weight, preferably 40 to 70% by weight, of at least one alkyl (meth)acrylate monomer (a); 0.1 to 30% by weight, preferably 5 to 25% by weight, of at least one acrylonitrile-butadiene rubber (b) having an acrylonitrile content of less than 45% by weight, based on the total weight of the acrylonitrile-butadiene rubber; 0.1 to 20 wt. %, preferably 5 to 15 wt. %, of a flexibilizer (c) selected from polyester-based urethane (meth)acrylate oligomers or (meth)acrylate-terminated acrylonitrile-butadiene oligomers; 0.1 to 30% by weight, preferably 5 to 20% by weight, of at least one core-shell graft polymer (d) other than component (b); 0.1 to 15 wt. %, preferably 0.1 to 10 wt. %, of at least one adhesion promoter; 0.5 to 5 wt. %, more preferably 1 to 2 wt. %, of at least one reducing agent; 0.01 to 1% by weight, more preferably 0.01 to 0.1% by weight, of at least one inhibitor; 0.1 to 5 wt. %, more preferably 0.1 to 2 wt. %, of at least one thixotropic agent; 0.01 to 1 wt. %, more preferably 0.01 to 0.5 wt. %, of at least one chelating agent; and 1-20 wt. % of at least one catalyst.

[0068] Preparation method The two-component curable adhesive composition according to the present invention can be prepared by the following steps: (i) adding to component (a), if present, an inhibitor and a chelating agent; (ii) dissolving component (b) in the mixture by mixing until a homogeneous solution is obtained; (iii) adding component (d), if present, and stirring until a smooth paste is obtained; (iv) adding component (c), and other additives, if present, to the paste and mixing until all components are dispersed to obtain component A; and (v) A catalyst (component B) is prepared and stored separately and mixed with component A before use.

[0069] The equipment used for mixing, stirring, dispersing, etc. is not particularly limited. Equipment equipped with a stirrer and heater, such as an automatic mortar, Henschel mixer, three-roll mill, ball mill, planetary mixer, or bead mill, can be used. These equipment may also be used in appropriate combination. The method for preparing the two-component curable adhesive composition is not particularly limited, as long as the above components are uniformly mixed in the composition.

[0070] Laminate and electronic device According to a third aspect of the present invention, provided herein is a laminate comprising a first substrate, a second substrate, and an adhesive layer sandwiched therebetween, wherein the first substrate and the second substrate are independently selected from glass, resin, and metal, and the adhesive layer is formed by curing an adhesive composition of the present invention.

[0071] The first substrate and / or the second substrate can be a single material and a single layer, or can include multiple layers of the same or different materials. The layers can be continuous or discontinuous.

[0072] The substrate of the articles described herein can have a variety of properties, including rigidity (e.g., a stiff substrate, i.e., a substrate that cannot be bent using two hands or that breaks when an attempt is made to bend it using two hands), flexibility (e.g., a flexible substrate, i.e., a substrate that can be bent with less than two hands), porosity, electrical conductivity, lack of electrical conductivity, and combinations thereof.

[0073] The substrate of the article can be in a variety of forms, including, for example, fibers, threads, yarns, woven fabrics, nonwoven fabrics, films (e.g., polymeric films, metallized polymeric films, continuous films, discontinuous films, and combinations thereof), foils (e.g., metal foils), sheets (e.g., metal sheets, polymeric sheets, continuous sheets, discontinuous sheets, and combinations thereof), and combinations thereof.

[0074] In a preferred embodiment, at least one of the substrates may be selected from metals, such as metal fired pastes, aluminum, tin, molybdenum, silver, conductive metal oxides such as indium tin oxide (ITO), fluorine-doped tin oxide, and aluminum-doped zinc oxide; glasses such as inked glass and bare glass; and resins such as polycarbonate, polybutylene terephthalate, and polyamide. Further suitable metals include copper, gold, palladium, platinum, aluminum, indium, silver-coated copper, silver-coated aluminum, tin, and tin-coated copper. Preferably, both substrates are selected from one of the aforementioned materials.

[0075] The two-component curable adhesive composition of the present invention can be cured at room temperature within the range of 15 to 35°C for 1 to 3 days.

[0076] As will be appreciated, the time and temperature cure profile of each two-part curing adhesive composition will vary, and different compositions may be designed to provide cure profiles that are particularly suited to industrial manufacturing processes.

[0077] According to a fourth aspect of the present invention, provided herein is an electronic device comprising the laminate of the present invention or manufactured using the adhesive composition according to the present invention.

[0078] The two-part curable adhesive composition of the present invention can be applied to a substrate using any suitable application method, including, for example, automated fine line dispensing, jet dispensing, slot die coating, roll coating, gravure coating, transfer coating, pattern coating, screen printing, spray coating, filament coating, extrusion, air knife, trailing blade, brushing, dipping, doctor blade, offset gravure coating, rotogravure coating, and combinations thereof. The two-part curable adhesive composition can be applied as a continuous or discontinuous coating, in single or multiple layers, and combinations thereof.

[0079] Purpose According to a fifth aspect of the present invention, provided herein is the use of an adhesive composition according to the present invention or a laminate according to the present invention in the manufacture of electronic devices.

[0080] Suitable electronic devices include, but are not limited to, wearable electronic devices (e.g., watches and eyeglasses), portable electronic devices (e.g., phones (e.g., cell phones and smartphones), cameras, tablets, e-readers, monitors (e.g., monitors used in hospitals by medical professionals, athletes, and individuals), watches, calculators, mice, touchpads, joysticks, etc.), computers (e.g., desktop computers, laptop computers), computer monitors, televisions, media players, or other electronic components. [Example]

[0081] The following examples are intended to aid those skilled in the art in better understanding and practicing the present invention. The scope of the present invention is not limited by the examples, but is defined in the appended claims. Unless otherwise specified, all ingredients and percentages are by weight.

[0082] raw materials: Methyl methacrylate is available from Lucite International. Nipol® DN401L is an acrylonitrile-butadiene rubber with an acrylonitrile content of 19% by weight and is available from Zeon Corporation. Nipol® DN2850 is an acrylonitrile-butadiene rubber having an acrylonitrile content of 28% by weight and is available from Zeon Corporation. Nipol® 1052 is an acrylonitrile-butadiene rubber having an acrylonitrile content of 33% by weight and is available from Zeon Corporation. Nipol® 4050 is an acrylonitrile-butadiene rubber having an acrylonitrile content of 40% by weight and is available from Zeon Corporation. Nipol® 4580 is an acrylonitrile-butadiene rubber having an acrylonitrile content of 45% by weight and is available from Zeon Corporation. Hypro® 1300X33LC VTBNX is a methacrylate-terminated acrylonitrile-butadiene oligomer available from Huntsman. Hypro® 2000X168LC is a methacrylate terminated polybutadiene available from Huntsman. BR641D is a polybutadiene urethane acrylate oligomer available from BOMAR Specialties LLC. BR204 is a polyether-based urethane acrylate oligomer available from BOMAR Specialties LLC. BR7432GB is a polyester-based urethane acrylate oligomer available from BOMAR Specialties LLC. Kane Ace® FM50 is an acrylic core-shell polymer available from KANEKA BELGIUM NV. Methacrylic acid is an adhesion promoter and is available from Roehm. Harcryl 1228 is an adhesion promoter available from Harcros Chemicals. Methylhydroquinone is an inhibitor and is available from Sigma Aldrich. VERSENE® 220E is a tetrasodium ethylenediaminetetraacetate tetrahydrate-based chelating agent available from DOW. N,N-dimethyl-p-toluidine is a reducing agent and is available from RSA Corporation. Aerosil 200 is a fumed silica available from Evonik. Perkabox GB-50 is 50% dibenzoyl peroxide in a phthalate-free carrier and is available from Nouryon.

[0083] Test Method: viscosity: The viscosity in the present invention was measured using a Brookfield viscometer with a 27# spindle over a temperature range of 25° C. A viscosity of less than 25,000 mPa·s is acceptable.

[0084] Stability testing of ingredient A: After mixing all of the components of component A, the Examples and Comparative Examples were visually inspected. If a uniform composition was observed, it was recorded as "stable"; if not, it was recorded as "phase separated." Only "stable" was acceptable.

[0085] Preparation of test samples Each test piece was made from two cleaned polyamine (PA) resin sheets of different sizes (the large sheet with a hole in the center had dimensions of 40 mm in width and length and 3 mm in thickness; the small sheet had dimensions of 30 mm in width and length and 3 mm in thickness), glass beads with a diameter of 0.127 mm, and a two-component curing adhesive of the present invention example / comparative example.

[0086] First, the PA sheet was wiped with isopropanol. Then, a two-component curing composition was mixed with a dispenser. When another small PA sheet was joined, the composition was 275 mm thick. 2 A sufficient amount of adhesive beads was dispensed around the hole in the large PA sheet to form a bonded area of ​​275 mm. Glass beads were then scattered on the bond line to act as a gap controller; a small PA sheet was then placed on top of the adhesive, resulting in an effective bonded area of ​​275 mm. 2 The assembly was clamped at 23°C and 50% relative humidity for 24 hours until the adhesive had cured.

[0087] Push-out strength test Push-out strength tests were conducted using a universal testing machine equipped with a punch at 23±2°C and 50%±5% relative humidity. The punch applied a compressive force to the smaller sheet through the hole in the larger sheet at an extrusion rate of 2 mm / min until the assembly could no longer support the load. The maximum load was recorded and divided by the bonded area to calculate the push-out strength.

[0088] Oleic acid tolerance test Test samples were prepared according to the method described above and allowed to cure for 24 hours. Afterward, 100% pure oleic acid was applied using a transfer pipette along the edge of the overlap bond, allowing the oleic acid to be drawn to the center of the sample by capillary action. The oleic acid should completely fill any open spaces around the adhesive. The samples were then aged for 300 hours at 65°C and 90% relative humidity. The aged samples were removed and placed at room temperature. After 2 hours, the aged samples were tested for push-out strength according to the method described above.

[0089] Retention of extrusion strength The retention rate was calculated according to the following formula: Retention rate = (extrusion strength after aging / extrusion strength before aging) × 100%. A retention rate of greater than 50% is acceptable, and greater than 70% is desirable.

[0090] Examples 1 to 12 (Ex. 1 to Ex. 12) and Comparative Examples 1 to 4 (CEx. 1 to CEx. 4) Adhesives were prepared using the components in the amounts (parts by weight) shown in Tables 1 and 2 by the following method, test samples were prepared by the above method, and characteristic tests were conducted by the above method. The evaluation results are shown in Tables 1 and 2.

[0091] Preparation method: All examples and comparative examples were prepared according to the following procedure: (i) adding an inhibitor and a chelating agent to an alkyl (meth)acrylate monomer (a); (ii) dissolving acrylonitrile-butadiene rubber (b) in the above mixture by mixing until a homogeneous solution is obtained; (iii) adding the core-shell graft polymer (d) and stirring until a smooth paste is obtained; (iv) adding the flexibilizer (c) and other additives to the paste and mixing until all components are dispersed to obtain Component A; and (v) Mixing with a catalyst (component B) before use.

[0092] [Table 1]

[0093] [Table 2]

[0094] As can be seen from Tables 1 and 2, compositions having component (b) with an acrylonitrile content outside the claimed range or having a flexibilizer different from that of the present invention either suffered from phase separation and poor processability or did not provide satisfactory chemical resistance to oleic acid.

[0095] While several preferred embodiments have been described, many modifications and variations are possible in light of the above teachings. It is therefore to be understood that the invention may be practiced otherwise than as specifically described without departing from the scope of the appended claims.

Claims

1. (a) at least one alkyl (meth)acrylate monomer; (b) at least one acrylonitrile-butadiene rubber having an acrylonitrile content of less than 45% by weight, based on the total weight of the acrylonitrile-butadiene rubber; and (c) at least one flexibilizing agent selected from polyester-based urethane (meth)acrylate oligomers and / or (meth)acrylate-terminated acrylonitrile-butadiene oligomers; Component A comprising: Component B, which comprises at least one catalyst A two-component curable adhesive composition comprising:

2. 10. The two-part curing adhesive composition of claim 1, wherein the composition optionally comprises (d) at least one core-shell graft polymer other than component (b).

3. 2. The two-part curing adhesive composition of claim 1, wherein the at least one alkyl (meth)acrylate monomer (a) is selected from esters of C1-C6 monofunctional alcohols with (meth)acrylic acid, preferably methyl acrylate, methyl methacrylate, ethyl acrylate or methacrylate, n-propyl or isopropyl acrylate or methacrylate, butyl (meth)acrylate (all isomers), and hexyl (meth)acrylate; esters of high molecular weight alcohols having up to 12 carbon atoms, preferably lauryl (meth)acrylate, 2-ethylhexyl (meth)acrylate, hexyl (meth)acrylate, isodecyl (meth)acrylate, and the like; more preferably esters of C1-C4 monofunctional alcohols with (meth)acrylic acid; and even more preferably methyl methacrylate.

4. 2. The two-part curing adhesive composition according to claim 1, wherein the acrylonitrile-butadiene rubber (b) has an acrylonitrile content of 10 to 42 wt %, preferably 20 to 40 wt %, more preferably 30 to 40 wt %, based on the total weight of the acrylonitrile-butadiene rubber.

5. The two-part curing adhesive composition according to claim 1, wherein the acrylonitrile-butadiene rubber (b) has a glass transition temperature (Tg) of -15 to -45°C, preferably -30 to -35°C.

6. 10. The two-part curing adhesive composition of claim 1, wherein the at least one flexibilizer (c) has a molecular weight of less than 200,000 g / mol.

7. 2. The two-component curing adhesive composition according to claim 1, wherein the polyester-based urethane (meth)acrylate oligomer is selected from monofunctional polyester-based urethane (meth)acrylate oligomers and / or multifunctional polyester-based urethane (meth)acrylate oligomers, preferably difunctional polyester-based urethane acrylate oligomers.

8. 2. The two-part curable adhesive composition according to claim 1, wherein the polyester-based urethane (meth)acrylate oligomer has a weight average molecular weight (Mw) of 10,000 to 40,000 g / mol.

9. 3. The two-part curing adhesive composition of claim 2, wherein the core-shell graft polymer (d) is selected from methacrylate-butadiene-styrene (MBS) graft copolymers, styrene-butadiene-styrene (SBS) graft copolymers, acrylate-styrene-acrylic acid (ASA) graft copolymers, acrylonitrile-butadiene-styrene graft copolymers (ABS), and combinations thereof.

10. 10. The two-part curing adhesive composition of claim 1, wherein component A further comprises an additive selected from adhesion promoters, inhibitors, chelating agents, reducing agents, thixotropic agents, and combinations thereof.

11. 2. The two-part curing adhesive composition of claim 1, wherein the catalyst in Component B is selected from benzoyl peroxide, cumene hydroperoxide, tertiary butyl hydroperoxide, dicumyl peroxide, tertiary butyl peroxide acetate, tertiary butyl perbenzoate, ditertiary butyl azodiisobutyronitrile, and combinations thereof.

12. The following steps: (i) adding the inhibitor and chelating agent, if present, to component (a); (ii) dissolving component (b) in the mixture by mixing until a homogeneous solution is obtained; (iii) adding component (d), if present, and stirring until a smooth paste is obtained; (iv) adding component (c), and other additives, if present, to the paste and mixing until all components are dispersed to obtain component A; and (v) preparing and storing the catalyst (Component B) separately and mixing it with Component A before use; A method for preparing the two-component curable adhesive composition according to any one of claims 1 to 11, comprising:

13. A laminate comprising a first substrate, a second substrate, and an adhesive layer sandwiched therebetween, wherein the first substrate and the second substrate are independently selected from glass, resin, and metal, and the adhesive layer is formed by curing the adhesive composition according to claim 1.

14. An electronic device comprising the laminate according to claim 13, or an electronic device produced using the adhesive composition according to any one of claims 1 to 11.

15. Use of the adhesive composition according to any one of claims 1 to 11 or the laminate according to claim 13 in the manufacture of an electronic device.