Two-component (2K) curable compositions

Abstract

The present invention provides a two-component (2K) curable composition comprising: (A) a first component comprising: i) at least one cyanoacrylate monomer represented by formula 1: H2C═C(CN)—COOR (1) wherein: R is selected from C1-C 18 Alkyl, C3‑C 18 Cycloalkyl, C2-C 15 Alkenyl, C6-C 18 Aryl, C7-C 15 Arylalkyl and C3‑C 15 allyl group; and ii) a peroxide catalyst; and iii) at least one cure accelerator for the at least one cyanoacrylate monomer i); (B) a second component comprising: i) at least one free radical curable compound; and, ii) at least one transition metal compound, wherein, when the components are mixed together, the peroxide catalyst initiates cure of the at least one free radical curable compound and the at least one transition metal compound initiates cure of the at least one cyanoacrylate monomer, and further wherein the at least one free radical curable compound comprises at least one unsaturated polyester polymer containing at least two cycloolefinic double bonds.

Description

Technical Field

[0001] The present invention relates to two-component (2K) curable compositions based on cyanoacrylate monomers.

[0002] More specifically, the present invention relates to a two-component (2K) free radical curable composition comprising at least one cyanoacrylate monomer in a first component and at least one unsaturated polyester in a second component. Background Art

[0003] When using adhesives to assemble structures, it can be challenging to determine the right composition that provides the required bond strength and setting speed to facilitate production. While some adhesives provide strong structural bonds, they take hours to set and require parts to be stored until they reach a strength suitable for handling. Conversely, compositions that provide the fastest cure may not be able to withstand loads or withstand thermal or mechanical stresses.

[0004] Curable cyanoacrylate compositions are widely recognized for their ability to bond to a variety of substrates—including plastics, metals, elastomers, and porous materials—and their ability to develop bond strength in a matter of minutes and, depending on the particular substrate, often in a matter of seconds. The polymerization of cyanoacrylate monomers is initiated by nucleophilic species found on most surfaces under normal atmospheric conditions: this surface chemistry of initiation means that when two surfaces are in intimate contact with a small layer of cyanoacrylate placed between them, there is often sufficient initiating species available. And based on this initiation chemistry, cyanoacrylates can find utility in high-volume manufacturing environments.

[0005] However, the properties of cyanoacrylate adhesives – particularly shear / peel strength, durability and toughness – are often compromised when the adhesive is exposed to elevated temperatures, elevated relative humidity or polar solvents. In the latter case, the adhesive may exhibit blooming, where a white cloud settles along the bond line and creates aesthetic issues. Perhaps more importantly, cyanoacrylates can be very brittle when fully cured and may have low impact strength. As a result, bonded joints formed by the adhesives are unable to withstand heavy loads: this is obviously detrimental because structural adhesives, by definition, become part of the assembly and should not fail when the substrates to which they are bonded are impacted or when stresses reach yield point.

[0006] To alleviate the speed vs. strength dilemma, some authors have attempted to formulate hybrid adhesive technologies designed to eliminate the limitations of instant adhesives and provide rapid structural bonds with the necessary shear / peel strength and durability.

[0007] US 2017335151 A (Ward et al.) discloses a two-part curable composition comprising: (a) a first part comprising a cyanoacrylate composition comprising a cyanoacrylate component, and a rubber toughening agent comprising (i) a reaction product of a combination of ethylene, methyl acrylate, and a monomer having a carboxylic acid cure site, (ii) a dimer of ethylene and methyl acrylate, and a combination of (i) and (ii); and (b) a second part comprising: a 2-substituted benzothiazole or a derivative thereof, wherein the 2-substituent is C 1-20 Alkyl, C 2-20 Olefin group, C 8-20 Alkylbenzyl, C 1-20 Alkylamino, C 1-20 Alkoxy, C 1-20 Alkyl hydroxyl, ether, sulfenamide, C 1-20 Thioalkyl or C 1-20 Thioalkoxy; and wherein at least one of the first part or the second part further comprises: a component containing at least two (meth)acrylate functional groups, at least one benzonitrile compound substituted with at least two or more electron-withdrawing groups selected from halogen, -NO2 or -CN and combinations thereof, and at least one anhydride component.

[0008] US2017327616 A1 (Kenichi et al.) describes a two-part curable composition comprising: a first reagent containing at least 2-cyanoacrylate; a second reagent containing at least a polymer having a hydrolyzable silyl group, wherein an elastomer and a curing catalyst for the above-mentioned polymer are each contained in at least one of the first reagent and the second reagent in a predetermined amount.

[0009] U.S. Pat. No. 8,742,048 (Hersee et al.) discloses a two-part curable composition comprising: (a) a first part comprising a cyanoacrylate component and a cationic catalyst; and (b) a second part comprising a cationically curable component, wherein when mixed together, the cationic catalyst initiates cure of the cationically curable component.

[0010] U.S. Pat. No. 9,371,470 (Barnes et al.) describes a two-part curable composition comprising: (a) a first part comprising a cyanoacrylate component and a peroxide catalyst; and (b) a second part comprising a free radical curable component and a transition metal, wherein when mixed together, the peroxide catalyst initiates cure of the free radical curable component and the transition metal initiates cure of the cyanoacrylate component.

[0011] Despite this prior art, it would be desirable to provide an adhesive system that combines the characteristics of an instant adhesive, such as the rapid set-up time and ability to bond to a variety of substrates, such as metals and plastics, observed with cyanoacrylates, with improved bond strength on a wider variety and / or selection of substrates. Given practical considerations, it would also be desirable to provide a two-part reactive adhesive with reduced odor and flammability that can be mixed in a 1:1 volume ratio without compromising shelf life stability or adhesive performance. Summary of the invention

[0012] According to a first aspect of the present invention, there is provided a two-component (2K) composition comprising:

[0013] (A) a first component comprising:

[0014] i) at least one cyanoacrylate monomer represented by Formula 1:

[0015] H2C═C(CN)—COOR(1)

[0016] Where: R is selected from C1-C 18 Alkyl, C3-C 18 Cycloalkyl, C2-C 15 Alkenyl, C6-C 18 Aryl, C7-C 15 Aralkyl and C3-C 15 Allyl;

[0017] ii) a peroxide catalyst; and

[0018] iii) at least one curing accelerator for the at least one cyanoacrylate monomer i);

[0019] (B) a second component comprising:

[0020] i) at least one free radical curable compound; and,

[0021] ii) at least one transition metal compound,

[0022] wherein, when the components are mixed together, the peroxide catalyst initiates the curing of the at least one free radical curable compound and the at least one transition metal compound initiates the curing of the at least one cyanoacrylate monomer, and

[0023] Further wherein the at least one free radical curable compound comprises at least one unsaturated polyester polymer containing at least two cycloolefinic double bonds.

[0024] The composition according to the invention exhibits advantageous cohesive strength and fixing time on various substrates when the two components are mixed.

[0025] The two-component (2K) curable composition may preferably be characterized in that it comprises 50 to 99.98 wt. %, such as 90 to 99 wt. %, i) of the at least one cyanoacrylate monomer, based on the weight of component (A). Independently or additionally, the two-component (2K) composition may preferably be characterized in that it comprises 0.1 to 10 wt. %, such as 0.1 to 5 wt. %, ii) of the peroxide catalyst, based on the total weight of the composition.

[0026] Preferably, the curing accelerator for at least one cyanoacrylate monomer i) is selected from the group consisting of: calixarene; oxacalixarene; silacrown; crown ether; cyclodextrin; poly(ethylene glycol) di(meth)acrylate; ethoxylated hydrogen-containing compounds, and combinations thereof. Independently of or in addition to this selection, the two-component (2K) curable composition may be characterized in that it contains 0.01 to 10% by weight of iii) the at least one curing accelerator, based on the total weight of the composition.

[0027] In an important embodiment of the present invention, component (B) is further characterized in that it contains a rheology modifier. In this regard, good results have been obtained when component (B) further contains 1 to 5 wt. % of hydrophobic fumed silica, based on the weight of the composition.

[0028] Preferably, the unsaturated polyester (UPS) of component (B) is substantially free of styrene and is characterized by a weight average molecular weight (Mw) of 1000-1000 Daltons, for example 2000 to 10000 Daltons. In addition, the unsaturated polyester (UPS) should preferably contain C5 to C8 cyclic moieties, which can be strained cyclic moieties. Independently of or in addition to these structural preferences, it is preferred that the two-component (2K) curable composition is characterized by comprising 40 to 95 wt. % of i) at least one unsaturated polyester polymer (UPS), based on the weight of component (B).

[0029] In one embodiment of the invention, the first component (A) is contained in a first chamber of a dual chamber cartridge and the second component (B) is contained in a second chamber of the dual chamber cartridge. The chambers are ideally of equal volume.

[0030] According to a second aspect of the present invention there is provided a cured product obtained from a two component (2K) composition as defined above and in the appended claims. The cured product initially exhibits excellent strength and retains strength after heat aging.

[0031] The invention also provides the use of the cured reaction product as defined above and in the appended claims as a structural adhesive.

[0032] definition

[0033] As used herein, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0034] As used herein, the term "comprising" is synonymous with "including", "containing", and is inclusive or open-ended and does not exclude other unrecited members, elements or method steps.

[0035] As used herein, the term "consisting of excludes any element, ingredient, member or method step not specified.

[0036] As used herein, the term "consisting essentially of" limits the scope of a claim to the specified elements, ingredients, members, or method steps, and those additional elements, ingredients, members, or method steps that do not materially affect the basic and novel characteristics of the claimed invention.

[0037] When amounts, concentrations, sizes and other parameters are expressed in the form of ranges, preferred ranges, upper values, lower values ​​or preferred upper and lower values, it should be understood that any range obtainable by combining any upper value or preferred value with any lower value or preferred value is also specifically disclosed, regardless of whether the obtained range is explicitly mentioned in the context.

[0038] Furthermore, according to standard understanding, weight ranges expressed as "from 0" specifically include 0 wt %: the ingredient defined by the range may or may not be present in the composition.

[0039] The words "preferred", "preferably", "desirably" and "particularly" are generally used to refer to embodiments of the present disclosure that may provide specific benefits under certain circumstances. However, the listing of one or more better, preferred, desirable or particular embodiments does not mean that other embodiments are not useful, and is not intended to exclude those other embodiments from the scope of the present disclosure.

[0040] As used in this application, the word "may" is used in a permissive sense—that is, meaning potentially—rather than in a mandatory sense.

[0041] As used herein, room temperature is 23° C.±2° C. As used herein, “ambient conditions” refers to the temperature and pressure of the environment to which a composition is exposed or to which a coating or substrate of the coating is exposed.

[0042] In the context of the present invention, a "two-component (2K) composition" is understood to be a composition in which the first component (A) and the second component (B) must be stored in separate containers due to their (high) reactivity. The two components are mixed only shortly before application and then react, usually without additional activation, to form bonds and thus a polymer network. Higher temperatures can be applied here to accelerate the crosslinking reaction.

[0043] As used herein, alone or as part of another group, "C1-C n An "alkyl" group refers to a monovalent group containing 1 to n carbon atoms, which is a radical of an alkane and includes straight-chain and branched organic groups. Thus, a "C1-C 30 "Alkyl" group refers to a monovalent group containing 1 to 30 carbon atoms, which is a radical of an alkane and includes straight-chain and branched organic groups. Examples of alkyl groups include, but are not limited to, methyl; ethyl; propyl; isopropyl; n-butyl; isobutyl; sec-butyl; tert-butyl; n-pentyl; n-hexyl; n-heptyl; and 2-ethylhexyl. In the present invention, such alkyl groups may be optionally interrupted. Independently or additionally, such alkyl groups may be unsubstituted or may be substituted with one or more substituents, such as halogen, nitro, cyano, amide, amino, sulfonyl, sulfinyl, sulfanyl, sulfoxy, urea, thiourea, sulfamoyl, sulfonamide, carbonyl, carboxyl, and hydroxyl. It should generally be noted that alkyl groups (C1-C 18 Alkyl), for example, an alkyl group containing 1 to 12 carbon atoms (C1-C 12 alkyl) or an alkyl group containing 1 to 6 carbon atoms (C1-C6 alkyl).

[0044] As specific examples of substituted alkyl groups, there can be mentioned "C1-C 18 "Haloalkyl" group means a C1-C 18 Alkyl groups, where C1-C 18 At least one of the hydrogen atoms of the alkyl group is replaced by a halogen atom.

[0045] The term “C3–C 18 "Cycloalkyl" is understood to mean a saturated, monocyclic, bicyclic or tricyclic hydrocarbon radical having 3 to 18 carbon atoms. In general, it should be noted that cycloalkyl (C3-C 12Cycloalkyl). Examples of cycloalkyl include: cyclopropyl; cyclobutyl; cyclopentyl; cyclohexyl; cycloheptyl; cyclooctyl; adamantane; and norbornane. In the present invention, such cycloalkyl may be optionally interrupted. Independently or additionally, such cycloalkyl may be unsubstituted or may be substituted with one or more substituents, such as halogen, nitro, cyano, amide, amino, sulfonyl, sulfinyl, sulfanyl, sulfoxy, urea, thiourea, sulfamoyl, sulfonamide, carbonyl, carboxyl and hydroxyl.

[0046] As used herein, “C6-C 18 "Aryl" groups used alone or as part of a larger moiety - as in "aralkyl" - refer to optionally substituted monocyclic, bicyclic and tricyclic ring systems, wherein the monocyclic ring system is aromatic or at least one of the rings in the bicyclic or tricyclic ring system is aromatic. Bicyclic and tricyclic ring systems include benzo-fused 2-3 membered carbon rings. Exemplary aryl groups include: phenyl; indenyl; naphthyl, tetrahydronaphthyl, tetrahydroindenyl; tetrahydroanthracenyl; and anthracenyl. And it can be noted that phenyl is preferred.

[0047] As used herein, “C2-C 15 "Alkenyl" refers to a hydrocarbon group having 2 to 15 carbon atoms and at least one olefinic unsaturation unit. The alkenyl group may be straight chain, branched or cyclic, and may be optionally substituted. As understood by those of ordinary skill in the art, the term "alkenyl" also includes groups having "cis" and "trans" configurations, or "E" and "Z" configurations. However, it is generally noted that alkenyl groups containing 2 to 10 (C 2-10 ) or 2 to 8 (C 2-8 ) carbon atom. 12Examples of alkenyl groups include, but are not limited to: —CH═CH2; —CH═CHCH3; —CH2CH═CH2; —C(═CH2)(CH3); —CH═CHCH2CH3; —CH2CH═CHCH3; —CH2CH2CH═CH2; —CH═C(CH3)2; —CH2C(═CH2)(CH3); —C(═CH2)CH2CH3; —C(CH3)═CHCH3; —C(CH3)CH═CH2; —CH═CHCH2CH2CH3; —CH2C H═CHCH2CH3; —CH2CH2CH═CHCH3; —CH2CH2CH2CH═CH2; —C(═CH2)CH2CH2CH3; —C(CH3)═CHCH2CH3; —CH(CH3)CH═CHCH; —CH(CH3)CH2CH═CH2; —CH2CH═C(CH3)2; 1-cyclopent-1-enyl; 1-cyclopent-2-enyl; 1-cyclopent-3-enyl; 1-cyclohex-1-enyl; 1-cyclohex-2-enyl; and 1-cyclohex-3-enyl. In the present invention, such alkenyl groups may be optionally interrupted. Independently or additionally, such alkenyl groups may be unsubstituted or may be substituted by one or more substituents, such as halogen, nitro, cyano, amide, amino, sulfonyl, sulfinyl, sulfanyl, sulfoxy, urea, thiourea, sulfamoyl, sulfonamide, carbonyl, carboxyl and hydroxyl.

[0048] As used herein, “C3-C 15 "Allyl" refers to a -CHR-CR'═CR"R'" group having 3 to 15 carbon atoms, wherein R, R', R" and R'" are independently selected from H and C1-C4 alkyl, provided that the group contains at least one allylic hydrogen.

[0049] As used herein, the term "C2-C 12 "Alkynyl" refers to an unsaturated straight or branched hydrocarbon having 2 to 12 carbon atoms and at least one carbon-carbon triple bond. Alkynyl groups may be straight or branched and may be optionally substituted. Exemplary alkynyl groups include ethynyl, prop-1-yn-1-yl and but-1-yn-1-yl. In the present invention, such alkynyl groups may be optionally interrupted. Independently or additionally, such alkenyl groups may be unsubstituted or may be substituted with one or more substituents, such as halogen, nitro, cyano, amide, amino, sulfonyl, sulfinyl, sulfanyl, sulfoxyl, urea, thiourea, sulfamoyl, sulfonamide, carbonyl, carboxyl and hydroxyl.

[0050] As used herein, "alkylaryl" refers to an aryl group substituted with an alkyl group, and "substituted alkylaryl" refers to an alkylaryl group further bearing one or more substituents as described above.

[0051] As used herein, the term "hetero" refers to a group or moiety that contains one or more heteroatoms such as N, O, Si and S. Thus, for example, "heterocycle" refers to a cyclic group having, for example, N, O, Si or S as part of the ring structure. "Heteroalkyl" and "heterocycloalkyl" moieties are alkyl and cycloalkyl groups, respectively, as defined above, that contain N, O, Si or S as part of their structure.

[0052] As used herein, the phrase "optionally interrupted" refers to a group as defined above that is uninterrupted or interrupted between adjacent carbon atoms by: oxygen (O); sulfur (S); or heteroaryl N (R"), wherein R" is H, C1-C6 alkyl or C6-C 18 For example, with respect to the above formula 1 herein, R can be a C1-C 18 Alkyl or C1-C 12 alkyl.

[0053] The term "cyclic" refers to alicyclic or aromatic substituents which may or may not be substituted and / or contain heteroatoms and may be monocyclic, bicyclic or polycyclic.

[0054] As used herein, "(meth)acrylate" and like terms are intended to include both acrylates and methacrylates.

[0055] The term "curing accelerator" herein is intended to include any material that acts as a curing accelerator (or curing agent) for the compound in question. The accelerator may be catalytic or reactive.

[0056] As used herein, the term "crown ether" refers to a macrocyclic polyether whose structure exhibits a conformation with a so-called cavity that can capture cations by coordinating with a lone pair of electrons on an oxygen atom (McGraw-Hill Dictionary of Scientific and Technical Terms (3rd Edition 1984)). Crown ethers are a type of macrocyclic ligand.

[0057] As used herein, the term "silicon dioxide" refers to amorphous silicon dioxide (SiO2). As used herein, the term "fumed silica" is synonymous with "pyrogenic silica" and refers to silicon dioxide formed in a flame or at high temperatures sufficient to decompose organic materials.

[0058] The term "hydrophobic silica" refers to any silica whose surface has been treated with a silylating agent, such as a halosilane such as an alkylchlorosilane, a siloxane such as dimethylsiloxane, or a silazane, so as to functionalize the -OH groups with silyl (Si-Rn) groups.

[0059] The molecular weights referred to in this specification may be measured by gel permeation chromatography (GPC) using polystyrene calibration standards, as performed according to ASTM3536.

[0060] "Acid value" or "acid number" is a measure of the amount of free acid present in a compound: the acid number is the number of milligrams of potassium hydroxide required to neutralize the free acid present in one gram of a substance (mgKOH / g). Any measured acid number given herein is determined according to German standard DIN53402.

[0061] Unless otherwise stated, the OH values ​​given herein were obtained according to Deutsche (DGF) Einheitsmethodenzur Untersuchung von Fetten, Fettprodukten, Tensidenundver-wandten Stoffen (Gesamtinhaltsverzeichnis 2016) C-V17b (53).

[0062] Unless otherwise specified, the viscosity of the coating compositions described herein is measured using a Brookfield viscometer (Model RVT) under standard conditions of 20°C and 50% relative humidity (RH). The viscometer is calibrated using silicone oils with known viscosities varying between 5,000 cps and 50,000 cps. A set of RV spindles connected to the viscometer is used for calibration. The coating composition is measured by using a No. 6 spindle at a speed of 20 rpm for 1 minute until the viscometer is balanced. The calibration is then used to calculate the viscosity corresponding to the equilibrium reading.

[0063] The term "substantially free" should similarly be interpreted to mean that the composition in question contains less than 0.25% by weight of the compound or element in question. DETAILED DESCRIPTION

[0064] Component A

[0065] i) Cyanoacrylate monomer

[0066] The cyanoacrylate component includes i) at least one cyanoacrylate monomer represented by Formula 1:

[0067] H2C═C(CN)—COOR(1)

[0068] Where: R is selected from C1-C 18 Alkyl, C3-C 18 Cycloalkyl, C2-C 15 Alkenyl, C6-C 18 Aryl, C7-C 15 Aralkyl and C3-C15 Allyl.

[0069] Preferably, R in Formula 1 is selected from C1-C 12 Alkyl, C3-C 12 Cycloalkyl and C3-C 12 Allyl. As preferred monomers according to formula 1, which can be used alone or in combination, mention may be made of: methyl cyanoacrylate; ethyl 2-cyanoacrylate (ECA); n-propyl 2-cyanoacrylate; isopropyl 2-cyanoacrylate; n-butyl 2-cyanoacrylate; tert-butyl 2-cyanoacrylate; octyl cyanoacrylate; and 3-methoxyethyl cyanoacrylate.

[0070] Based on the weight of component (A), the composition should contain 50 to 99.98 wt %, such as 90 to 99 wt % i) of the at least one cyanoacrylate monomer. In an alternative but not mutually exclusive preferred expression, based on the weight of the composition, the composition should contain 25 to 50 wt % i) of the at least one cyanoacrylate monomer.

[0071] ii) Peroxide Catalyst

[0072] The composition of the present invention comprises ii) at least one peroxide catalyst. The composition should generally comprise 0.1 to 10 wt%, such as 0.1 to 5 wt%, of ii) the at least one peroxide catalyst, based on the total weight of the composition.

[0073] Although certain peroxides, such as dialkyl peroxides, have been disclosed as useful catalysts in U.S. Pat. No. 3,419,512 (Lees) and U.S. Pat. No. 3,479,246 (Stapleton), and indeed may be useful herein, hydroperoxides represent a preferred class of catalysts for use in the present invention. Furthermore, although hydrogen peroxide itself may be used, the most desirable catalyst is an organic hydroperoxide. For the sake of completeness, the definition of hydroperoxide includes materials such as organic peroxides or organic peresters, which decompose or hydrolyze to form organic hydroperoxides in situ: examples of such peroxides and peresters are cyclohexyl peroxide and hydroxycyclohexyl peroxide, respectively, and t-butyl perbenzoate.

[0074] In one embodiment of the present invention, the catalyst comprises or consists of at least one hydroperoxide compound represented by the formula:

[0075] R p OOH

[0076] Where: R p is a hydrocarbon radical containing up to 18 carbon atoms, and

[0077] Preferably, Rp It is C1-C 12 Alkyl, C6-C 18 Aryl or C6-C 18 Aralkyl.

[0078] As exemplary catalysts that can be used alone or in combination, mention may be made of: cumene hydroperoxide (CHP); p-menthane hydroperoxide; tert-butyl hydroperoxide (TBH); tert-butyl perbenzoate; tert-amyl hydroperoxide; 1,2,3,4-tetramethylbutyl hydroperoxide; benzoyl peroxide; dibenzoyl peroxide; 1,3-bis(tert-butylperoxyisopropyl)benzene; diacetyl peroxide; butyl 4,4-bis(tert-butylperoxy)valerate; p-chlorobenzoyl peroxide; tert-butylcumene peroxide; di-tert-butyl peroxide; diisopropylbenzene peroxide; 2,5-dimethyl-2,5-di-tert-butylperoxyhexane; 2,5-dimethyl-2,5-di-tert-butyl-peroxyhex-3-yne; and 4-methyl-2,2-di-tert-butylperoxypentane.

[0079] iii) Accelerator

[0080] Component (A) of the composition of the present invention includes iii) at least one curing accelerator for the at least one cyanoacrylate monomer i). The composition should generally contain 0.01 to 10 wt %, such as 0.1 to 5 wt % or 0.1 to 3 wt % of iii) the at least one curing accelerator, based on the total weight of the composition. Such accelerators may be selected from: calixarenes and oxacalixarenes; silacrown ethers; crown ethers; cyclodextrins; poly(ethylene glycol) di(meth)acrylates; ethoxylated hydrogen-containing compounds, and combinations thereof.

[0081] Among the calixarenes and oxacalixarenes, many are known and reported in the patent literature. Instructive disclosures include: U.S. Patent No. 4,556,700; U.S. Patent No. 4,622,414; U.S. Patent No. 4,636,539; U.S. Patent No. 4,695,615; U.S. Patent No. 4,718,966; and U.S. Patent No. 4,855,461. And with respect to calixarenes, those compounds in the following structures are useful herein:

[0082]

[0083] Where: R 1 is alkyl, alkoxy, substituted alkyl or substituted alkoxy;

[0084] R 2 is H or alkyl; and

[0085] n is 4, 6 or 8.

[0086] A particularly desirable calixarene is tetrabutyltetrakis[2-ethoxy-2-oxoethoxy]calix-4-arene.

[0087] A variety of suitable crown ethers are known. For example, examples that can be used herein alone or in combination include: 15-crown-5; 18-crown-6; dibenzo-18-crown-6; benzo-15-crown-5; dibenzo-24-crown-8; dibenzo-30-crown-10; tribenzo-18-crown-6; asymmetric dibenzo-22-crown-6; dibenzo-14-crown-4; dicyclohexyl-18-crown-6; dicyclohexyl-24-crown-8; cyclohexyl-12-crown-4; 1,2-decalyl-15-crown-5; 1 ,2-naphtho-15-crown-5; 3,4,5-naphthyl-16-crown-5; 1,2-methyl-benzo-18-crown-6; 1,2-methylbenzo-5,6-methylbenzo-18-crown-6; 1,2-tert-butyl-18-crown-6; 1,2-vinylbenzo-15-crown-5; 1,2-vinylbenzo-18-crown-6; 1,2-tert-butyl-cyclohexyl-18-crown-6; asymmetric dibenzo-22-crown-6 and 1,2-benzo-1,4-benzo-5-oxy-20-crown-7. See U.S. Pat. No. 4,837,260 (Sato), the disclosure of which is expressly incorporated herein by reference.

[0088] Without intending to limit the present invention, useful silacrown ether compounds can be represented by the following structure:

[0089]

[0090] Where: R 3 and R 4 It is an organic group that does not itself cause polymerization of the cyanoacrylate monomer;

[0091] R 5 is H or CH3; and

[0092] n is an integer of 1 to 4.

[0093] Suitable R 3 and R 4 Examples of the group are alkyl, alkoxy such as methoxy and ethoxy, and aryloxy such as phenoxy. 3 and R 4 The radical may contain halogen or other substituents, an example being trifluoropropyl. 4 and R 5 The radical of the group is a basic group such as amino, substituted amino and alkylamino.

[0094] Specific examples of silacrown ether compounds that can be used in the composition of the present invention include:

[0095]

[0096] Dimethylsilyl-11-crown-4;

[0097]

[0098] Dimethylsilyl-14-crown-5-ether; and

[0099]

[0100] Dimethylsilyl-17-crown-6-ol.

[0101] Reference to the disclosure of US Pat. No. 4,906,317 (Liu) may be instructive in the use of such silacrown ethers.

[0102] Many cyclodextrins are useful in the present invention, for example, those described and claimed in U.S. Pat. No. 5,312,864 (Wenz), the disclosure of which is expressly incorporated herein by reference: Hydroxy derivatives of α-, β-, or γ-cyclodextrin that are at least partially soluble in cyanoacrylates would be particularly suitable choices for use as the accelerator component herein.

[0103] As described herein above, poly(ethylene glycol) di(meth)acrylates can be used in the present invention. More specifically, exemplary poly(ethylene glycol) di(meth)acrylates for use herein have the following structure:

[0104]

[0105] Wherein: n is ≥3, for example, 3 to 30 or 3 to 20.

[0106] Thus, specific examples include, but are not limited to: PEG200DMA (n≈4); PEG400DMA (n≈9); PEG600DMA (n≈14); and PEG800DMA (n≈19), where the designated number (eg, 400) represents the average molecular weight of the diol portion of the molecule.

[0107] As described herein above, ethoxylated hydrogen-containing compounds can be used in the present invention. More specifically, exemplary ethoxylated hydrogen-containing compounds useful herein have the following structure:

[0108]

[0109] Where: C m The alkyl or alkenyl chain may be straight or branched;

[0110] m is an integer from 1 to 30, for example an integer from 5 to 20;

[0111] n is an integer from 2 to 30, for example an integer from 5 to 15, and

[0112] R can be H or C1-C6 alkyl.

[0113] In addition, other suitable promoters may be included in the following structure:

[0114]

[0115] Wherein: R and R' are independently selected from hydrogen, C 1-6 Alkyl, C 1-6 Alkoxy, alkyl sulfide, alkyl halide, carboxylic acid and esters, sulfinic acid, sulfonic acid and sulfurous acid and esters, phosphinic acid, phosphonic acid and phosphorous acid and esters;

[0116] Z is a polyether bond;

[0117] n is 1-2;

[0118] p is 1-3;

[0119] g is 1-12, as defined above, R' is the same as R, and g is the same as n.

[0120] One particularly desirable chemical in this class is:

[0121]

[0122] Where (n+m)≥12.

[0123] iv) Stabilizer

[0124] Component (A) of the present invention should preferably include one or more stabilizers. "Stabilizer" for the purposes of the present invention is understood to be an antioxidant, UV stabilizer, free radical stabilizer, anionic stabilizer or hydrolysis stabilizer, which can be used in particular to inhibit the decomposition of peroxides present in the composition. In this context, the stabilizer may account for up to 10% by weight or up to 5% by weight, based on the total weight of component (A).

[0125] Standard commercial examples of stabilizers suitable for use herein include: sterically hindered phenols; thioethers; benzotriazoles; benzophenones; benzoates; amines of the hindered amine light stabilizer (HALS) type; phosphorus; sulfur trioxide and its hydrolysis products; methanesulfonic acid; sulfur; boron trifluoride; boron trifluoride etherate; and mixtures thereof. In a particular embodiment, the stabilizer may be selected from benzoquinone, naphthoquinone, anthraquinone, hydroquinone, methoxyhydroquinone, butylated hydroxytoluene, and mixtures thereof. The disclosures of U.S. Pat. No. 5,530,037 and U.S. Pat. No. 6,607,632 may be instructive to the skilled artisan.

[0126] For the sake of completeness, it should be noted that stating that a stabilizer is preferably included in component (A) does not exclude the inclusion of a stabilizer in component (B). However, the total amount of stabilizer present in both components should not exceed 10% by weight, based on the total weight of the composition.

[0127] Component B

[0128] i) Unsaturated polyester

[0129] Component B of the present composition comprises at least one unsaturated polyester polymer (UPS) containing at least two cycloolefinic double bonds. The unsaturated polyester (UPS) is ideally substantially free of styrene and should preferably be characterized by a weight average molecular weight (Mw) of at least 1000 Daltons, such as 2000 to 10000 Daltons. It is further preferred that the polymer comprises a C5 to C8 cyclic moiety; the moiety is not excluded from being present in a bicyclic structure, such as a bicyclic structure formed when the cyclic structure comprises a bridging hydrocarbon moiety to form two rings in the overall structure.

[0130] Based on the weight of component (B), the composition should contain 40 to 95 wt%, such as 75 to 95 wt% of i) said at least one unsaturated polyester polymer (UPS). In an alternative but not mutually exclusive preferred expression, based on the weight of the composition, the composition should contain 20 to 50 wt% of i) said at least one unsaturated polyester polymer (UPS).

[0131] Commercial examples of unsaturated polyesters (UPS) according to this component include Palatal K785V01 from DSM Resins. In addition, such unsaturated polyesters (UPS) can be prepared by several different methods.

[0132] In a first exemplary method, an unsaturated polyester polymer (UPS) is obtained by a Diels-Alder reaction of carbon-carbon double bonds on the polymer chain of an unsaturated polyester polymer (UP) having no cycloolefinic double bonds but having at least two carbon-carbon double bonds with a cyclic hydrocarbon compound such as cyclopentadiene, methylcyclopentadiene, ethylcyclopentadiene, isopropylcyclopentadiene, 1,3-cyclohexadiene, 1-methyl-4-isopropylcyclohexa-1,3-diene, 2-methyl-5-isopropylcyclohexa-1,3-diene or a mixture thereof.

[0133] In this first method, the reaction temperature and the addition of the cyclic hydrocarbon compound during the reaction are controlled so that the Diels-Alder reaction of the carbon-carbon double bond and the cyclic hydrocarbon compound can occur at any point of the reaction. By way of preferred example, the unsaturated polyester polymer containing cycloolefinic double bonds is obtained by adding dicyclopentadiene to the reaction vessel at or near the end of the unsaturated polyester resin synthesis at ≥150°C: the dicyclopentadiene decomposes into cyclopentadiene and the cyclopentadiene then reacts with the carbon-carbon double bonds of the unsaturated polyester polymer.

[0134] The reactant unsaturated polyester polymer (UP) without cyclic olefinic double bonds has at least one dicarboxylic acid olefin part and can be derived by the condensation reaction of: a) at least one diol; b) at least one α,β-ethylenically unsaturated dicarboxylic acid or its ester-forming derivative; and, optionally, c) at least one dicarboxylic acid or its ester-forming derivative which does not contain any unsaturated aliphatic groups.

[0135] Suitable diols (a) for use in this context include saturated and unsaturated aliphatic and alicyclic dihydroxy compounds and aromatic dihydroxy compounds. These diols preferably have a molecular weight of 250 Daltons or less. When used in this article, the term "diol" should be understood to include its equivalent ester derivatives, however, the premise is that the molecular weight requirement is only related to the diol and not to its derivatives. Exemplary ester derivatives include acetates of diols and, for example, ethylene oxide or ethylene carbonate for ethylene glycol.

[0136] Preferred diols are those having 2 to 10 carbon atoms. Mention may be made, as examples of these diols, of ethylene glycol; propylene glycol; 1,3-propanediol; 1,2-butanediol; 2-methylpropanediol; 1,3-butanediol; 1,4-butanediol; 2,3-butanediol; neopentyl glycol; hexanediol; decanediol; hexamethylene glycol; cyclohexanedimethanol; resorcinol; and hydroquinone. Mixtures of such diols may be used, but in this respect it is generally preferred that at least about 60 mol %, preferably at least 80 mol %, based on the total diol content, are identical diols.

[0137] In a preferred embodiment, the diol is selected from the group consisting of: ethylene glycol; propylene glycol; 1,3-propylene glycol; 1,2-butanediol; 1,3-butanediol; 1,4-butanediol; 2,3-butanediol; neopentyl glycol; hexamethylene glycol; cyclohexanedimethanol; and mixtures thereof. Most preferably, the diol is ethylene glycol or neopentyl glycol.

[0138] The term "dicarboxylic acid" used hereinafter includes equivalents of dicarboxylic acids having two functional carboxyl groups, which behave substantially similar to dicarboxylic acids when reacting with glycols and diols to form polyesters. These equivalents include esters and reactive derivatives that form esters, such as acyl halides and anhydrides, but the prerequisite is that any of the preferred molecular weights mentioned relate to acids rather than their equivalent esters or ester-forming derivatives. Specifically, it is preferred that all dicarboxylic acid monomers [(ii), (iii)] have a molecular weight less than 300 daltons. Therefore, dicarboxylic acid esters with a molecular weight greater than 300 daltons or acid equivalents of dicarboxylic acids with a molecular weight greater than 300 daltons are included, provided that the acid has a molecular weight less than 300 daltons. In addition, the dicarboxylic acid may contain any substituent or combination that does not substantially interfere with polymer formation and the use of the polymer of the present invention.

[0139] Exemplary α,β-ethylenically unsaturated dicarboxylic acids (b) have 4 to 6 carbon atoms (C4-C6) and include: maleic acid; fumaric acid; citraconic acid, chloromaleic acid; allylsuccinic acid; itaconic acid; and, mesaconic acid. Maleic acid may be mentioned as being preferred.

[0140] The other dicarboxylic acids (c) which do not contain any unsaturated aliphatic groups and are suitable for use in the above context include aliphatic, alicyclic and / or aromatic dicarboxylic acids. Preferred dicarboxylic acids are those selected from alkyl dicarboxylic acids having a total of 2 to 16 carbon atoms and aryl dicarboxylic acids having a total of 8 to 16 carbon atoms. Representative alkyl dicarboxylic acids include: glutaric acid; adipic acid; pimelic acid; succinic acid; sebacic acid; azelaic acid; and malonic acid. Preferred adipic acid may be mentioned here. Representative aryl dicarboxylic acids include: terephthalic acid; phthalic acid; and isophthalic acid.

[0141] The condensation reaction for forming the reactant polyester (UP) will occur under conditions for removing water, which conditions are generally composed of one or more of: a temperature of 120° to 250°C; application of a vacuum; and, use of a solvent to promote azeotropic distillation. Conventional catalysts for promoting esterification reactions may be used in the reaction. The catalysts that may be used in an amount of 0.01 to 1 wt %, such as 0.01 to 0.5 wt %, based on the total weight of the reactants are generally compounds of tin, antimony, titanium or zirconium. Mention may be made in this context of titanium alkoxides and their derivatives, for example tetraethyl titanate, tetraisopropyl titanate (TIPT), tetra-n-propyl titanate, tetra-n-butyl titanate, tetra(2-ethylhexyl) titanate, isopropyl butyl titanate, tetrastearyl titanate, diisopropoxy-bis(acetylacetonate)titanium, di-n-butoxy-bis(triethanolamino)titanium, monoacetyl tributyl titanate, monoacetyl triisopropyl titanate and tetrabenzoic acid titanate; titanium complex salts, for example alkali metal titanium oxalate and alkali metal titanium malonate, potassium hexafluorotitanate and complexes of titanium with hydroxycarboxylic acids, for example tartaric acid, citric acid or lactic acid; titanium dioxide / silicon dioxide coprecipitates; hydrated alkali-containing titanium dioxide; and the corresponding zirconium compounds.

[0142] In a second exemplary method for forming the unsaturated polyester (UPS) of this component, dicyclopentadiene (DCPD) can be directly included as a monomer in the synthesis of the unsaturated polyester (UP) polymer from its constituent monomers [(a)-(c)], as described above. The production of such dicyclopentadiene-containing unsaturated polyester polymers is considered to be well known to the skilled artisan. In any case, reference may be made to: Smith et al. The Use of Dicyclopentadiene in Polyesters, Proceedings of the 22nd Annual Technical Conference, SPI, Reinforced Plastics Division, Washington, DC (1967); and Zimmermann et al. Modification of Unsaturated Polyesters with Dicyclopentadiene Qette-Serfen-Anstrichmittel 66, #9, 670-678 (1964).

[0143] In a third exemplary method, the unsaturated polyester (UPS) of the component is obtained by direct reaction of the monomers [(a)-(c)] described above with a norbornene compound containing a -OH or -CO2H reactive functional group. Exemplary monomers contained in the condensation reaction mixture include: 5-norbornene-2-carboxylic acid; 5-norbornene-2,3-dicarboxylic acid; 5-norbornene-2,3-dicarboxylic anhydride, 5-norbornene-2,3-dicarboxylic acid diethyl ester; 5-norbornene-2,3-dicarboxylic acid dimethyl ester; 5-norbornene-2,3-dicarboxylic anhydride; 5-norbornene-2,2-dimethanol; 5-norbornene-2,3-dimethanol; 5-norbornene-2-methanol; 5-norbornene-2-ol; and 5-norbornene-2-yl acetate.

[0144] ii) Transition metal compounds

[0145] As defined above, component (B) of the composition of the present invention should include 100 to 10000 ppm by weight, for example 100 to 5000 ppm by weight of at least one transition metal compound, based on the weight of the component. In particular, it is preferred that the at least one transition metal compound is selected from copper, vanadium, cobalt and iron compounds.

[0146] It may be noted that Cu(I) and Cu(II) compounds are particularly preferred and in fact effective results have been obtained where component B comprises 100 to 5000 ppm, e.g. 500 to 2500 ppm total Cu(I) and Cu(II) compounds based on the weight of the component.

[0147] As a non-exhaustive list of suitable copper(I) and copper(II) compounds, mention may be made of: copper(II) 3,5-diisopropylsalicylate hydrate; copper(II) bis(2,2,6,6-tetramethyl-3,5-heptanedione); basic copper(II) phosphate; copper(II) chloride; copper(II) acetate monohydrate; tetra(acetonitrile)copper(I) hexafluorophosphate; copper(II) formate hydrate; copper(I) tetraacetonitrile trifluoromethanesulfonate; copper(II) tetrafluoroborate; copper(II) perchlorate; tetra(acetonitrile)copper(I) tetrafluoroborate; copper(II) hydroxide; copper(II) hexafluoroacetylacetonate(II) hydrate; and copper(II) carbonate.

[0148] For vanadium compounds, those compounds in which vanadium has 2+ and 3+ valence states are desirable. Examples of such vanadium (III) compounds include vanadyl naphthanate and vanadyl acetylacetonate. Also, when present, these vanadium (III) compounds should be used in an amount of up to 5000 ppm by weight, e.g., 500 ppm to 2500 ppm by weight, based on the weight of component B.

[0149] For the cobalt compound, compounds in which the cobalt has a 2+ valence state are desirable. Examples of such cobalt (II) compounds include cobalt naphthenate, cobalt tetrafluoroborate, and cobalt acetylacetonate. Also, when present, these cobalt (II) compounds should be used in an amount of up to 5000 ppm by weight, such as 500 ppm to 2500 ppm by weight, based on the weight of component B.

[0150] For the iron compound, compounds in which the iron has a 3+ valence state are desirable. Examples of such iron (III) compounds include iron acetate; iron acetylacetonate; iron tetrafluoroborate; iron perchlorate; and iron chloride. When present, these iron (III) compounds should be used in an amount of up to 1,000 ppm by weight, e.g., 100 ppm to 1000 ppm by weight, based on the weight of component B.

[0151] iii) Hydrophobic fumed silica

[0152] Component B of the composition of the present invention preferably comprises 1 to 5 wt % of hydrophobic fumed silica, based on the weight of the composition.

[0153] The hydrophobic fumed silica used should be characterized by at least one of the following: a) an average particle size of less than 5 microns as measured by dynamic light scattering; b) a particle size of 20 to 200 m as measured by Brunauer-Emmett-Teller (BET); 2 / g specific surface area; and c) as measured according to ASTM B527-15 Standard Test Method for Tap Density of Metal Powders and Compounds, 20 to 100 g / l tap density. More specifically, the fumed silica should be characterized by at least one of the following: a) an average particle size of 1 to 10 microns; b) 100 to 250 m 2 / g specific surface area; and c) 25 to 75 g / l tap density. And, for the sake of completeness, it should be noted that these conditions a) to c) are not mutually exclusive, and the fumed silica can meet one, two or ideally three of the conditions.

[0154] Additives and auxiliary ingredients

[0155] The compositions obtained in the present invention will generally further comprise adjuvants and additives that can impart improved properties to these compositions. Such adjuvants and additives, which can be contained in one or both components of a two-component (2K) composition independently of one another, include: photoinitiators; photosensitizers; plasticizers; stabilizers, including UV stabilizers; chelating agents; antioxidants; coupling agents; adhesion promoters; rheological modifiers; fillers; toughening agents; reactive diluents; desiccants; fungicides; flame retardants; corrosion inhibitors; fluorescent markers; pigments; and / or non-reactive diluents.

[0156] Such adjuvants and additives can be used in such combinations and proportions as desired, as long as they do not adversely affect the properties and basic performance of the composition. Although there may be exceptions in some cases, these adjuvants and additives should not account for more than 50% by weight of the total composition, preferably should not account for more than 20% by weight of the composition.

[0157] For the sake of completeness, it should be noted that auxiliary materials and additives containing reactive groups are typically blended into the appropriate component of a two (2K) component composition to ensure its storage stability. Non-reactive materials may be formulated in one or both of the two components.

[0158] As mentioned above, component (B) of the present invention comprises compounds having free radically active unsaturated groups. In certain embodiments, it may be advantageous for component (A) to include, in addition to the peroxide compound, one or more photoinitiator compounds, in particular photoactive compounds which generate free radicals under applied radiation, which can initiate polymerization by addition to the C=C double bond.

[0159] The photoinitiator used in these embodiments should be selected from Norrish Type I and Norrish Type II photoinitiators. Norrish Type I free radical photoinitiators undergo a Norrish Type I reaction upon exposure to actinic radiation: the reaction is defined by IUPAC as the α-cleavage of an excited carbonyl compound to produce an acyl-alkyl radical pair (from an acyclic carbonyl compound) or an acyl-alkyl diradical (from a cyclic carbonyl compound) as the major photoproduct. Norrish Type II free radical photoinitiators undergo a Norrish Type II reaction upon exposure to actinic radiation: the reaction is defined by IUPAC as the photochemical abstraction of a γ-hydrogen by an excited carbonyl compound to produce a 1,4-diradical as the major photoproduct.

[0160] Non-limiting examples of photoactive compounds that undergo Norrish I cleavage include, but are not limited to: 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one (Irgacure 907, available from BASF); 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 (Irgacure 369); and 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholino)phenyl]-1-butanone (Irgacure 379). Non-limiting examples of photoactive compounds that undergo a Norrish II reaction include, but are not limited to: bis(2,6-dimethylbenzoyl)-2,4,4-trimethylpentylphosphine oxide (Irgacure 1800, 1850 and 1700); 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (Lucerin TPO, available from BASF); (2,4,6-trimethylbenzoyl)-phenylphosphinate ethyl ester (Lucerin TPO-L); bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; isopropylthioxanthone; diethylthioxanthone; and 2-chlorothioxanthone. It is worth noting that Norrish II type photoinitiators generally require the presence of a suitable co-initiator - typically an amine, such as 2-dimethylaminoethyl benzoate - for which reason it can be recognized that Norrish I type photoinitiators are preferred.

[0161] The photoinitiator should be present in the photocurable composition in an amount of 0 to 5 wt %, such as 0 to 2.0 wt % or 0 to 1.5 wt %, based on the total weight of the composition.

[0162] The skilled artisan will recognize that a photosensitizer may be incorporated into the composition to increase the efficiency with which the energy delivered by the photoinitiator is used. The term "photosensitizer" is used according to its standard meaning to refer to any substance that increases the rate of photoinitiated polymerization or shifts the wavelength at which polymerization occurs: Odian, Principles of Polymerization 3 rd A guiding reference in this regard is provided in AT&T AG (1991), Page 222. When present, the photosensitizer should be used in an amount of 5 to 25% by weight based on the weight of the photoinitiator.

[0163] The use of photoinitiators - and where applicable photosensitizers - may produce residual compounds from photochemical reactions in the final cured product. Residues can be detected by conventional analytical techniques, such as: infrared, ultraviolet and NMR spectroscopy; gas or liquid chromatography; and mass spectrometry. Thus, the present invention may include a cured matrix (co)polymer and a detectable amount of residues from at least the photoinitiator. Such residues are present in small amounts and generally do not interfere with the desired physicochemical properties of the final cured product.

[0164] "Plasticizers" for the purposes of the present invention are substances which reduce the viscosity of the composition and thus promote its processability. Plasticizers herein may constitute up to 10% by weight or up to 5% by weight, based on the total weight of the composition, and are preferably selected from the following group: polydimethylsiloxanes (PDMS); diurethanes; ethers of monofunctional, linear or branched C4-C16 alcohols, such as Cetiol OE (available from Cognis Deutschland GmbH, Düsseldorf); rosin esters, butyrates, thiobutyrates, acetates, propionates and citrates; esters based on nitrocellulose and polyvinyl acetate; fatty acid esters; dicarboxylates; esters of fatty acids with OH groups or epoxidized; glycolates; benzoates; phosphates; sulfonates; trimellitates; epoxidized plasticizers; polyether plasticizers, such as end-capped polyethylene glycols or polypropylene glycols; polystyrene; hydrocarbon plasticizers; chlorinated paraffins; and mixtures thereof. Note that in principle phthalates can be used as plasticizers, but these are not preferred due to their toxicological potential.Preferably, the plasticizer comprises or consists of one or more polydimethylsiloxanes (PDMS).

[0165] As suitable adhesion promoters, mention may be made of: (meth)acrylic acid; Ebecry 1168, a methacrylated acidic adhesion promoter available from Radcure Corporation; Ebecry 1170, an acrylated acidic adhesion promoter available from Radcure Corporation; β-carboxyacrylates; Sartomer CN704, an acrylated polyester adhesion promoter available from Sartomer Corporation; and CD9050, a monofunctional acid ester CD9052 available from Sartomer Corporation; CD9052, a trifunctional acid ester available from Sartomer Corporation; and zinc diacrylate.

[0166] The compositions of the present invention may optionally contain a toughening rubber, which is ideally in the form of a rubber-modified epoxy resin, in the form of core-shell particles, or a combination thereof. The toughening rubber should have a glass transition temperature (Tg) of no greater than -25°C. g ): Preferably at least a portion of the toughened rubber should have a glass transition temperature (T) of -40°C or lower, more preferably -50°C or lower, and even more preferably -70°C or lower. g ).

[0167] Independent of the presence of rheology modifiers and in particular hydrophobic fumed silica in the composition, it is envisaged that the composition according to the invention may additionally contain fillers. Suitable here are, for example, chalk, lime powder, precipitated and / or pyrolyzed silicic acid, zeolites, bentonites, magnesium carbonate, diatomaceous earth, aluminum oxide, clay, talc, titanium oxide, iron oxide, zinc oxide, sand, quartz, flint, mica, glass powder and other ground minerals. Organic fillers may also be used, in particular carbon black, graphite, wood fiber, wood powder, sawdust, cellulose, cotton, pulp, cotton, wood chips, chopped straw, husks, ground walnut shells and other chopped fibers. Short fibers, such as glass fibers, glass filaments, polyacrylonitrile, carbon fibers, Kevlar fibers, polyethylene fibers, polyethylene powder and granular polytetrafluoroethylene may also be added.

[0168] Also suitable as fillers are hollow spheres with a mineral shell or a plastic shell. For example, these may be hollow glass spheres, which are available under the trade name Glass Commercially available. Plastic based hollow spheres can be used, e.g. or And they are described in EP0520426B1: They consist of inorganic or organic substances and each have a diameter of 1 mm or less, preferably 500 μm or less.

[0169] Fillers which impart thixotropy to the composition may be preferred for many applications: such fillers are also described as rheology aids, for example hydrogenated castor oil, fatty acid amides or expandable plastics such as PVC.

[0170] The total amount of filler present in the composition of the invention is preferably from 1 to 15 wt%, more preferably from 1 to 10 wt%, based on the total weight of the composition.The desired viscosity of the curable composition will generally be determined by the total amount of filler added.

[0171] In order to increase the shelf life even further, it is generally advisable to further stabilize the compositions according to the invention with respect to moisture penetration by using desiccants.

[0172] The presence of reactive diluents in the composition is not excluded, and may in fact be beneficial in modifying the properties of the cured adhesive. Reactant diluents that may be used alone or in combination include, but are not limited to: α,β-ethylenically unsaturated monocarboxylic acids containing 3 to 5 carbon atoms, such as acrylic acid, methacrylic acid, crotonic acid, and esters of these acids; α,β-ethylenically unsaturated dicarboxylic acids containing 4 to 6 carbon atoms, and anhydrides, monoesters, and diesters of these acids; vinyl esters; vinyl ethers; vinyl ketones; and aromatic or heterocyclic aliphatic vinyl compounds.

[0173] Representative examples of suitable esters of acrylic acid, methacrylic acid, and crotonic acid include, but are not limited to, those reacted with saturated aliphatic and alicyclic alcohols having from 1 to 20 carbon atoms, such as methyl acrylate, methyl methacrylate, methyl crotonate, ethyl acrylate, ethyl methacrylate, ethyl crotonate, propyl acrylate, propyl methacrylate, propyl crotonate, isopropyl acrylate, isopropyl methacrylate, isopropyl crotonate, n-butyl acrylate, n-butyl methacrylate, n-butyl crotonate, isobutyl acrylate, isobutyl methacrylate, isobutyl crotonate, tert-butyl acrylate, tert-butyl methacrylate, tert-butyl crotonate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, 2-ethylhexyl crotonate, lauryl acrylate, lauryl methacrylate, crotonate, Lauryl beanate, stearyl acrylate, stearyl methacrylate, stearyl crotonate, cyclohexyl acrylate, cyclohexyl methacrylate, cyclohexyl crotonate, trimethylcyclohexyl acrylate, trimethylcyclohexyl methacrylate, trimethylcyclohexyl crotonate, tetrahydrofurfuryl acrylate, tetrahydrofurfuryl methacrylate, tetrahydrofurfuryl crotonate, stearyl acrylate, stearyl methacrylate, stearyl crotonate, sulfoethyl acrylate, sulfoethyl methacrylate, sulfoethyl crotonate and isobornyl acrylate, isobornyl methacrylate and isobornyl crotonate; hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate and hydroxybutyl methacrylate; and polyalkylene glycol acrylates and polyalkylene glycol methacrylates. Representative examples of other ethylenically unsaturated polymerizable monomers include, but are not limited to, compounds such as the following: anhydrides of fumaric acid, maleic acid, and itaconic acid, monoesters and diesters of fumaric acid, maleic acid, and itaconic acid with alcohols such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, and tert-butanol. Representative examples of vinyl monomers include, but are not limited to, compounds such as vinyl acetate; vinyl propionate; vinyl ethers, such as vinyl ethyl ether; vinyl and vinylidene halides; and vinyl ethyl ketone. Representative examples of aromatic or heterocyclic aliphatic vinyl compounds include, but are not limited to, compounds such as styrene, α-methylstyrene, vinyl toluene, tert-butylstyrene, and 2-vinylpyrrolidone.

[0174] The reactive diluent may account for 0 to 10 wt %, such as 0 to 5 wt %, of the total weight of the composition.

[0175] The presence of non-reactive diluents in the composition of the invention is not excluded insofar as it is effective to adjust the viscosity thereof. For example, but for illustration only, the composition may contain one or more of the following: xylene; 2-methoxyethanol; dimethoxyethanol; 2-ethoxyethanol; 2-propoxyethanol; 2-isopropoxyethanol; 2-butoxyethanol; 2-phenoxyethanol; 2-benzyloxyethanol; benzyl alcohol; ethylene glycol; ethylene glycol dimethyl ether; ethylene glycol diethyl ether; ethylene glycol dibutyl ether; ethylene glycol diphenyl ether; diethylene glycol; diethylene glycol monomethyl ether; diethylene glycol monoethyl ether; diethylene glycol mono-n-butyl ether; diethylene glycol dimethyl ether; diethylene glycol diethyl ether; diethylene glycol di-n-butyl ether; propylene glycol butyl ether; propylene glycol phenyl ether; dipropylene glycol; dipropylene glycol monomethyl ether; dipropylene glycol dimethyl ether; dipropylene glycol di-n-butyl ether; N-methylpyrrolidone; diphenylmethane; diisopropylnaphthalene; petroleum fractions, such as products (available from Exxon); alkylphenols, such as tert-butylphenol, nonylphenol, dodecylphenol and 8,11,14-pentadecatrienylphenol; styrenated phenols; bisphenols; aromatic resins, especially those containing phenolic groups, such as ethoxylated or propoxylated phenols; adipates; sebacates; phthalates; benzoates; organic phosphates or sulfonates; and sulfonamides.

[0176] In addition to the above, it is preferred that the non-reactive diluent accounts for less than 10 wt%, in particular less than 5 wt% or less than 2 wt%, based on the total weight of the composition.

[0177] Exemplary Embodiments of Two-Component (2K) Compositions

[0178] In an exemplary embodiment of the present invention, a two-component (2K) composition comprises:

[0179] (A) a first component comprising:

[0180] 90 to 99 wt % of i) the at least one cyanoacrylate monomer represented by Formula 1, based on the weight of component (A):

[0181] H2C═C(CN)—COOR(1)

[0182] Where: R is selected from C1-C 12 Alkyl, C3-C 12 Cycloalkyl and C3-C 12 Allyl;

[0183] 0.1 to 10 wt % of ii) a peroxide catalyst, based on the total weight of the composition; and

[0184] 0.01 to 10 wt. % of iii) at least one curing accelerator for the at least one cyanoacrylate monomer i), based on the total weight of the composition;

[0185] (B) a second component comprising:

[0186] 40 to 95 wt. %, based on the weight of component (B), of i) at least one free radical curable unsaturated polyester polymer (UPS), wherein the unsaturated polyester (UPS) comprises C5 to C8 cyclic moieties, is substantially free of styrene, and has a weight average molecular weight (Mw) of 1000 to 10000 Daltons;

[0187] 100 to 10,000 ppm by weight, based on the weight of component (B), of ii) at least one transition metal compound selected from the group consisting of: copper compounds; vanadium compounds; cobalt compounds; and iron compounds; and,

[0188] 1 to 5 wt % of hydrophobic fumed silica, based on the weight of the composition,

[0189] wherein, when the components are mixed together, the peroxide catalyst initiates cure of the at least one free radical curable compound and the at least one transition metal compound initiates cure of the at least one cyanoacrylate monomer.

[0190] Methods and Applications

[0191] To form a defined two-component (2K) curable composition, the reactive components are brought together and mixed in a manner that causes them to harden. The reactive compounds should be mixed under sufficient shear to produce a homogeneous mixture. It is believed that this can be achieved without special conditions or special equipment. That is, suitable mixing devices may include: static mixing devices; magnetic stir bar devices; whisk devices; screw conveyors; batch mixers; planetary mixers; CW Brabender or type mixers; and high shear mixers, such as blade mixers and rotary impellers.

[0192] For small-scale applications, where volumes of less than 2 liters are usually used, the preferred packaging for two-component (2K) compositions would be side-by-side double cartridges or coaxial cartridges, in which two tubular chambers - usually of the same volume - are arranged side by side or placed inside each other and sealed with pistons: the actuation of these pistons allows the components to be extruded from the cartridges, advantageously through a tightly mounted static or dynamic mixer. For applications with larger volumes, the two components of the composition can advantageously be stored in drums or barrels: in this case, the two components are extruded by a hydraulic press, in particular through a follower plate, and supplied through a pipe to a mixing device which can ensure a fine and highly uniform mixing of the two components. In any case, for any packaging, it is important that the components are treated with an airtight and moisture-tight seal so that both components can be stored for a long time, ideally for 12 months or more.

[0193] Non-limiting examples of two-component dispensing apparatus and methods that may be suitable for the present invention include those described in US Pat. No. 6,129,244 and US Pat. No. 8,313,006.

[0194] Depending on the desired properties of the cured composition, the two components are typically mixed in a volume ratio of 5:1 to 1:5, e.g., 2:1 to 1:2 or 1.5:1 to 1:1.5, of component A:component B. The latter range includes a volume ratio of 1:1 component A:component B, which itself represents a preferred embodiment of the present invention.

[0195] Where applicable, the two-component (2K) curable composition should be broadly formulated to exhibit an initial viscosity at 25° C. of less than 200,000 mPa.s, for example less than 100,000 mPa.s, which is measured immediately after mixing, for example within a maximum of two minutes after mixing. Independently of or in addition to the viscosity properties, the two-component (2K) composition should be formulated to be bubble-free (foamy) upon mixing and subsequent curing. In addition, the two-component (2K) composition should be further formulated to exhibit at least one of the following properties: i) a maximum exotherm temperature of not more than 120° C., preferably not more than 100° C. and more preferably not more than 80° C.; and ii) a Shore A hardness of at least 50, preferably at least 60, more preferably at least 70 after curing and storage for 7 days at room temperature and 50% relative humidity.

[0196] According to the broadest method aspect of the present invention, the above-mentioned composition is applied to a substrate and then cured in situ. Before applying the composition, it is generally recommended to pre-treat the relevant surface to remove foreign matter: if applicable, this step can promote the subsequent adhesion of the composition thereto. Such treatments are known in the art and can be carried out in a single-stage or multi-stage manner consisting of, for example, one or more of the following treatments: etching treatment with an acid suitable for the substrate and an optional oxidizing agent; ultrasonic treatment; plasma treatment, including chemical plasma treatment, corona treatment, atmospheric plasma treatment and flame plasma treatment; immersion in an aqueous alkaline degreasing bath; treatment with an aqueous cleaning emulsion; treatment with a cleaning solvent, such as carbon tetrachloride or trichloroethylene; and water rinsing, preferably with deionized or demineralized water. In those cases where an aqueous alkaline degreasing bath is used, any degreasing agent remaining on the surface should be removed by rinsing the substrate surface with deionized or demineralized water.

[0197] In some embodiments, the adhesion of the coating composition of the present invention to the preferably pretreated substrate can be promoted by applying a primer thereto. In practice, a primer composition may be required to ensure effective fixation and / or curing time of the adhesive composition on the inert substrate. Although the skilled person will be able to select a suitable primer, guiding references for selecting a primer include, but are not limited to: U.S. Patent No. 3,855,040; U.S. Patent No. 4,731,146; U.S. Patent No. 4,990,281; U.S. Patent No. 5,811,473; GB2502554; and U.S. Patent No. 6,852,193.

[0198] The composition is then applied to the preferably pretreated, optionally primed surface of the substrate by conventional application methods, such as: brushing; roller coating, such as roller coating using a 4-applicator roller apparatus where the composition is solvent-free or a 2-applicator roller apparatus for solvent-containing compositions; knife application; printing methods; and spraying methods, including but not limited to air atomized spraying, air-assisted spraying, airless spraying, and high-volume low-pressure spraying. For coating, adhesive and sealant applications, it is recommended that the composition be applied to a wet film thickness of 10 to 500 μm. Applying thinner layers within this range is more economical and reduces the possibility of harmful thick cured areas. However, strict control must be exercised when applying thinner coats or layers to avoid the formation of discontinuous cured films.

[0199] The curing of the composition of the invention generally takes place at temperatures of -10°C to 175°C, preferably 0°C to 160°C, in particular 20°C to 160°C. Suitable temperatures depend on the specific compounds present and the desired curing rate and can be determined in the individual case by the skilled worker, if necessary using simple preliminary tests. Of course, curing at temperatures of 10°C to 35°C or 20°C to 30°C is particularly advantageous, since it avoids the need to heat or cool the mixture sufficiently from the usual most common ambient temperature. However, where applicable, the temperature of the mixture formed from the individual components of the two-component (2K) composition can be raised to above the mixing temperature and / or application temperature using conventional means including microwave induction.

[0200] The following examples are illustrative of the present invention and are not intended to limit the scope of the present invention in any way.

[0201] Example

[0202] The following materials were used in the examples:

[0203] Ethyl CA: ethyl cyanoacrylate obtained from Sigma Aldrich.

[0204] HPMA: 2-Hydroxypropyl methacrylate from Sigma Aldrich.

[0205] Stock solution 100: Boron trifluoride (diluted in ethyl cyanoacrylate monomer)

[0206] Stock Solution 127: Sulfur dioxide (diluted in ethyl cyanoacrylate monomer)

[0207] Levapren 900: Ethylene vinyl acetate copolymer available from Lanxess Deutschland GmbH.

[0208] 785V-01: an unsaturated polyester resin based on dicyclopentadiene (DCPD) from DSM Resins having a viscosity of 235 mPa.s.

[0209] Kayamer PM2: bis(2-methacryloyloxyethyl) hydrogen phosphate available from Nippon Kayaku.

[0210] TS720: hydrophobic fumed silica available from Cabot Corporation.

[0211] Example 1

[0212] Prepare components A and B by mixing the ingredients according to Table 1 below:

[0213] Table 1 Component (A)

[0214]

[0215] Component (B)

[0216]

[0217] Equal amounts of the components by weight were loaded into separate compartments of a 50 g cartridge and sealed at both ends. The cartridge was then loaded into a cartridge gun and a mixing tip was installed at the front. The two components were pushed into the mixing tip by applying constant pressure on the trigger to ensure thorough mixing before application to the substrate.

[0218] The substrates were abraded aluminum and GMBS hard plastic each having a thickness of 0.1 inch. The substrates were cut into a size of 2.5 cm x 10 cm (1" x 4") for tensile testing.

[0219] Tensile lap shear (TLS) testing was performed at room temperature based on ASTM D 3163-01 - Standard Test Method for Determining Strength of Adhesively Bonded Rigid Plastic Lap-Shear Joints in Shear by Tension Loading. The bond overlap area was 2.5 cm x 2.5 cm (1" x 1") and the bond thickness was 0.1 cm (40 mil).

[0220] The cohesive strength of the composition is measured using a creep test on a single adhesive bead. The bead is applied to the plate with 0.53g / m. The plate comprises a seam cut transverse to the direction in which the beads are applied. Each seam is 0.3cm wide and extends to one side of the plate. The adhesive beads are applied to the plate and bridged on the seam so that it does not sag into the seam itself. The plate is then placed in an oven at 105°F and balanced for 20 minutes. The 40 gram weights attached to the paper clip (size 1) are then suspended in the portion of the adhesive beads above the seam using the other end of the paper clip. The time required for the adhesive bead to break is called the bead time (Bead Time).

[0221] Fixture time (curing time) refers to the shortest time required for the adhesive to develop a handling strength such that the test sample can be removed from the fixture, loosened or handled without stressing the bond and affecting the bond strength. Fixture time is measured here according to ASTM D1144-99.

[0222] The results of these performance tests are given in Table 2 below.

[0223] Table 2

[0224]

[0225] Strength properties were also measured by tensile lap shear on samples cured and conditioned at 150°C for 250 hours.The heat aging test results are given in Table 3 below.

[0226] Table 3: Heat aging

[0227] Heat aging performance results Initial lap shear strength results

[0228] TLS, GBMS, 150℃@250h 13.00 12.70

[0229] TLS, Ab.Al, 150℃@250h 9.00 13.00

[0230] The results show the benefit of the included polyester: strength is maintained even after heat aging.

[0231] Example 2

[0232] This example investigates the inclusion of an acrylate monomer in component (B). In this context, components (A) and (B) were prepared by mixing the ingredients according to Table 4 below:

[0233] Table 4 Component (A)

[0234]

[0235] Component (B)

[0236]

[0237] Equal amounts of the components by weight were loaded into separate compartments of a 50 g cartridge and sealed at both ends. The cartridge was then loaded into a cartridge gun and a mixing tip was installed at the front. The two components were pushed into the mixing tip by applying constant pressure on the trigger to ensure thorough mixing before application to the substrate.

[0238] The substrates were worn aluminum and GMBS hard plastic each having a thickness of 0.1 inch. The substrates were cut into a size of 2.5 cm x 10 cm (1" x 4") for tensile testing.

[0239] The results of the above performance tests are given in Table 5 below.

[0240] Table 5

[0241]

[0242] In view of the foregoing description and examples, it will be apparent to those skilled in the art that equivalent modifications may be made thereto without departing from the scope of the claims.

Claims

1. A two-component (2K) curable composition comprising: (A) a first component comprising: i) 50 to 99.98 weight percent, based on the weight of component (A), of at least one cyanoacrylate monomer represented by Formula 1: H2C═C(CN)—COOR(1) in: R is selected from C1-C 18 Alkyl, C3-C 18 Cycloalkyl, C2-C 15 Alkenyl, C6-C 18 Aryl, C7-C 15 Aralkyl and C3-C 15 Allyl; and ii) a peroxide catalyst; and iii) at least one curing accelerator for the at least one cyanoacrylate monomer i); (B) a second component comprising: i) 40 to 95% by weight, based on the weight of component (B), of at least one unsaturated polyester polymer (UPS) comprising at least two cycloolefinic double bonds; ii) at least one transition metal compound, and, iii) 1 to 5 wt. % of hydrophobic fumed silica, based on the weight of the composition, wherein, when the components are mixed together, the peroxide catalyst initiates the curing of the at least one unsaturated polyester polymer (UPS) and the at least one transition metal compound initiates the curing of the at least one cyanoacrylate monomer, and The unsaturated polyester (UPS) comprises C5 to C8 cyclic moieties and is substantially free of styrene and is characterized by a weight average molecular weight (Mw) of 1000-10000 Daltons.

2. The two-component (2K) curable composition according to claim 1, wherein R in Formula 1 is selected from C1-C 12 Alkyl, C3-C 12 Cycloalkyl and C3-C 12 Allyl.

3. The two-component (2K) curable composition according to claim 1 or 2, wherein the peroxide catalyst comprises or consists of at least one hydroperoxide compound represented by the following formula: R p OOH Where: R p It is C1-C 12 Alkyl, C6-C 18 Aryl or C6-C 18 Aralkyl.

4. A two-component (2K) curable composition according to claim 1 or 2, wherein the peroxide catalyst is selected from the group consisting of cumene hydroperoxide (CHP); p-menthane hydroperoxide; tert-butyl hydroperoxide (TBH); tert-butyl perbenzoate; tert-amyl hydroperoxide; 1,2,3,4-tetramethylbutyl hydroperoxide; benzoyl peroxide; dibenzoyl peroxide; 1,3-bis(tert-butylperoxyisopropyl)benzene; diacetyl peroxide; butyl 4,4-bis(tert-butylperoxy)valerate; p-chlorobenzoyl peroxide; tert-butylcumene peroxide; di-tert-butyl peroxide; diisopropylbenzene peroxide; 2,5-dimethyl-2,5-di-tert-butylperoxyhexane; 2,5-dimethyl-2,5-di-tert-butyl-peroxyhex-3-yne; 4-methyl-2,2-di-tert-butylperoxypentane; and mixtures thereof.

5. The two-component (2K) curable composition according to claim 4, wherein the peroxide catalyst is t-butyl perbenzoate.

6. The two-component (2K) curable composition according to claim 1 or 2, comprising 0.1 to 10 wt. % of ii) the peroxide catalyst, based on the total weight of the composition.

7. A two-component (2K) curable composition according to claim 1 or 2, wherein the curing accelerator is selected from the following group: calixarene; oxacalixarene; silacrown ether; crown ether; cyclodextrin; poly(ethylene glycol) di(meth)acrylate; ethoxylated hydrogen-containing compounds; and combinations thereof.

8. The two-component (2K) curable composition according to claim 1 or 2, comprising 0.01 to 10% by weight of iii) the at least one curing accelerator, based on the total weight of the composition.

9. The two-component (2K) curable composition according to claim 1 or 2, wherein the at least one transition metal compound is selected from the group consisting of copper compounds; vanadium compounds; cobalt compounds; and iron compounds.

10. The two-component (2K) curable composition according to claim 1 or 2, wherein component (B) comprises 100 to 10000 ppm by weight of ii) the at least one transition metal compound, based on the weight of the component.

11. A cured product obtained from the two-component (2K) composition according to any one of claims 1 to 10.

12. Use of the cured reaction product according to claim 11 as a structural adhesive.

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