CURABLE COMPOSITIONS BASED ON CYCLIC THIOETHER COMPOUNDS AND USE THEREOF - Patent application

Abstract

The present invention relates to a curable composition that is liquid at room temperature and comprises at least one thioether compound (A), at least one initiator (B), and at least one catalyst (C), wherein said at least one thioether compound (A) comprises one at least difunctional cyclic thioether.

Description

[Technical Field]

[0001] The present invention relates to a curable composition based on at least one thioether compound containing an at least difunctional cyclic thioester, an initiator, and a catalyst. Furthermore, the present invention relates to the use of the curable composition for bonding, casting, and / or coating substrates. [Background technology]

[0002] Polyinsertion (or insertion polymerization, or polyinsertions) is a polymerization reaction in which a monomer is inserted between the growing chain and the initiator. One example is the Ziegler-Natta process, which produces linear olefins. In this process, the monomer binds to a free coordination site on a metal catalyst and inserts into the metal-carbon bond, resulting in chain growth (also known as "coordination polymerization"). Ring expansion polymerization occurs when the growing polymer chain is terminated by an initiator, as is known from cyclic metathetic catalysts. Initiators include not only metal complexes but also functional organic molecules such as lactones or esters. A summary of this process is published in a scientific paper by Chang and Waymouth in Polymer Chemistry (2017, Vol. 55, pp. 2892–2902, doi:10.1002 / pola.28635).

[0003] Thiiranes are sulfur-containing analogs of epoxides and, in contrast to epoxides, are only partially suitable for cationic polymerization. However, thiiranes favorably undergo polyaddition, anionic, or polyinsertion reactions. One possibility for polymerizing thiiranes via polyinsertion reactions is to use initiators bearing a (thio)carbonylthio group as an essential functional group. In this type of polymerization, the initiator is incorporated into the polymer and, by definition, consumed; it no longer functions as a catalyst. The resulting polythioethers are characterized by high resistance to media and flexibility at low temperatures, making them suitable as sealing masses for aviation and space travel. Furthermore, they are also suitable as high-refractive components in optical materials such as lenses and optical filters.

[0004] Thiirane can be obtained, for example, by reacting epoxide with thiourea, thiocyanate, or 3-methyl-2-benzothiazolinethione through direct sulfur atom transfer. US Patent No. 8,969,503 describes a melt extrusion method for producing thiirane from the corresponding epoxide using thiourea derivatives, thiocyanate, or phosphine sulfide as a sulfur donor. Further examples are described in JP 2019-008289 A, US Patent No. 6,631,021 A, JP 2001-163874 A, JP 2002-241499 A, and JP 2005-343910 A.

[0005] The synthesis method of cyclic polysulfides by thiirane (poly) ring insertion reaction is known in the art.Representative examples are published in the scientific paper by A. Kameyama, M. Kiyota and T. Nishikubo in "Tetrahedron Letters" (1994, Vol. 35, 26th edition, pp. 4571-4574) and in the scientific paper by A. Kameyama, Y. Murakami and T. Nishikubo in "Macromolecules" (1996, Vol. 29, 20th edition, pp. 6676-6678).

[0006] Japanese Patent No. 4,977,099 describes a method for preparing cyclic polysulfides having radically polymerizable groups and polymers obtained by polymerization of the radically polymerizable groups. The initiator used is 2,4-thiazolidinedione, which undergoes a (poly)ring insertion reaction with a thiirane monomer to form a cyclic polysulfide, which is then functionalized with an allyl group by reaction with 3-chloromethylstyrene. Thus, a polymer containing the cyclic polysulfide is obtained by radical polymerization. The disclosure suggests the use of the polymer as a topological gel. It is not intended for use as a curable composition.

[0007] Patent No. 3,976,438 discloses the reaction of a bifunctional aromatic haloformyl compound with an aromatic dithiol and the subsequent reaction of the product (aryl thiocarbonate) with a thiirane. At least one thiirane unit is inserted into the newly connected sulfur-carbonyl bond. The resulting polymers have a high sulfur content and a high refractive index. They are suitable for use as optical elements such as lenses, optical filters, coatings, or anti-reflective films. Again, no mention is made of their use as curable compositions.

[0008] Further suitable cyclic initiators are described in JP 2001-261834 A, JP 2005-281241 A, JP 2008-231349 A, and the scientific article by H. Kudo, S. Makino, A. Kameyama, and T. Nishikubo in the journal "Macromolecules" (2005, Vol. 38, 14th Edition, pp. 5964-5969, doi:10.1021 / ma047642h). The thiiranes used preferably have alkoxymethyl or phenoxymethyl groups. The use of thiiranes functionalized with allyl and propargyl ethers and cycloaliphatic groups is also described.

[0009] A scientific paper by Zhang et al. in Nature Communications (2020, Vol. 11, pp. 1–10, doi:10.1038 / s41467-020-17474-0) discloses polyrhodanine-based polycyclic polymers. Higher-functional initiators can be obtained by condensing rhodamine with difunctional or trifunctional aldehydes. Furthermore, crosslinking of the initiator is possible through N-functionalization of the rhodamine moiety. The final polyinsertion is carried out in the polyfunctional initiator backbone. Crosslinking of the polyether rings is largely limited by the ratio of initiator moieties used per polyether ring. This method makes it impossible to construct polymer structures containing highly crosslinked macrocyclic polythioether moieties. Summary of the Invention

[0010] The present invention aims to provide a single-component curable composition based on thioether compounds, which is liquid at room temperature and is suitable as an adhesive, casting material or coating material.

[0011] According to the present invention, the object is achieved by a curable composition according to claim 1, a use of said composition according to claim 12 and a method according to claim 14.

[0012] Advantageous embodiments of the composition according to the invention are set forth in the dependent claims, which can be combined in any way with one another.

[0013] The composition according to the present invention comprises the following components: a) at least one thioether compound (A), comprising at least one difunctional cyclic thioether; b) at least one initiator (B), and c) at least one catalyst (C).

[0014] The compositions of the present invention are liquid at room temperature and can be thermally cured.

[0015] The present invention will now be described in detail by way of examples using preferred embodiments and the following figures, which should not be construed as limiting. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a DSC curve of the composition according to the present invention. [Figure 2] FIG. 2 shows an isothermal measurement of the curable composition of FIG. 1 carried out at a temperature of 80°C. DETAILED DESCRIPTION OF THE INVENTION

[0017] For purposes of the present invention, "liquid" means that the loss modulus G" determined by measuring viscosity at 23°C is greater than the storage modulus G' of the respective component or composition.

[0018] For purposes of this invention, a composition is considered "curable" if it satisfies the conditions for cure while forming a solid, polymeric structure beyond the gel point. The gel point is the point at which the storage modulus G' and loss modulus G" are equal.

[0019] Where the indefinite article "a" or "an" is used, the plural "one or more" is also included unless expressly excluded.

[0020] "At least bifunctional" means that each molecule contains two or more units of each specified functional group, regardless of whether the functional groups are primary, secondary, or tertiary.

[0021] The compositions of the present invention can be single-component or multi-component. Preferably, the agglomerates (or aggregates, agglomerates, masses, substances, or masses) of the present invention are present as a single component.

[0022] By "single component" or "single component mass" it is meant that the reactive components of the mass are present together in a packaging unit and are mixed together.

[0023] The weight percentages set forth below are based on the total weight of all components of the composition, excluding additives, unless otherwise specified.

[0024] Component (A): Thioether compound The composition according to the present invention comprises, as component (A), at least one thioether compound, which comprises at least one at least difunctional cyclic thioether.

[0025] In other words, component (A) comprises at least one compound containing at least two cyclic thioethers (eg, at least two thiirane or thietane groups) as functional groups.

[0026] Therefore, in this specification and hereinafter, the term "thioether compound" is used for compounds having a cyclic thioether as a functional group.

[0027] Structurally, suitable thioether compounds (A) are not further limited and can be aromatic, aliphatic, or alicyclic thioether compounds.

[0028] In particular, the thioether compounds comprise one or more at least difunctional thiiranes (A1) and / or one or more at least difunctional thietanes (A2).

[0029] Preferably, the thioether compound comprises one or more at least difunctional thiiranes (A1).

[0030] As the thioether compound (A), long-chain thiolanes, thianes, and thiepanes are not preferred because of the very small ring strain and the associated low reactivity.

[0031] Preferably, component (A) is present in a proportion of 15% to 99% by weight, particularly preferably 25% to 98% by weight, based on the total weight of the composition excluding additives.

[0032] Ingredient (A1): Thiirane Component (A) contains, as a thioether compound, in particular at least one at least difunctional thiirane (A1). The use of at least difunctional thiirane (A1) allows the composition to be crosslinked to a higher degree than when monofunctional thiirane (A1) is used. Furthermore, the use of difunctional thiirane (A1) still makes it possible to produce agglomerates with a higher degree of crosslinking than is possible with polyfunctional initiators.

[0033] Preferably, the at least difunctional thiirane (A1) is present in a proportion of at least 5% by weight, more preferably at least 10% by weight, particularly preferably at least 15% by weight, based on the total weight of component (A1).

[0034] Apart from the at least difunctional thiiranes (A1), component (A1) may also comprise monofunctional thiiranes (A1).

[0035] The monofunctional thiirane (A1) is preferably present in a proportion of at most 95% by weight, more preferably at most 90% by weight, particularly preferably at most 85% by weight, based on the total weight of component (A1).

[0036] Preferred examples of thiirane (A1) include compounds obtained by substituting one or more epoxy groups with a thiirane group.

[0037] For example, starting compounds include bisphenol A epoxy resin, bisphenol F epoxy resin, biphenyl glycidyl epoxy resin, naphthalene diol diglycidyl ether, glycidyl ether of tris(hydroxyphenyl)methane, and glycidyl ether of tris(hydroxyphenyl)ethane, and mixtures thereof.

[0038] Additionally, fully or partially hydrogenated analogues of aromatic epoxy resins can all be used as starting compounds.

[0039] Examples of suitable thiiranes (A1) are given below.

[0040] Examples of the monofunctional thiirane (A1) include phenylepithiopropyl ether, 4-tert-butylphenylepithiopropyl ether, neodecanoic acid epithiopropyl ester, butylepithiopropyl ether, 2-ethylhexylepithiopropyl ether, cresylepithiopropyl ether, and cardanylepithiopropyl ether.

[0041] Examples of commercially available monofunctional epoxides from which similar thiiranes (A1) can be obtained include the product sold by Adeka under the trade name Glycirol ED 509-S, the product sold by Olin under the trade name DER727, the product sold by Hexion under the trade name Heloxy Modifier AQ, the product sold by Cardolite under the trade name Cardolite Ultra Lite 513, or the product sold by iPox Chemicals GmbH under the trade name iPox RD 17.

[0042] Examples of difunctional or higher functional aromatic thiiranes (A1) include 1,3-bis(epithioethyl)benzene, 1,4-bis(epithioethyl)benzene, bis[4-(epithioethyl)phenyl]methane, 2,2-bis[4-(epithioethyl)phenyl]propane, bis[4-(epithioethyl)phenyl]sulfide, bis[4-(epithioethyl)phenyl]sulfone, 4,4'-bis(epithioethyl)biphenyl, 1,3-bis(epithiopropyloxy)benzene, 1,4-bis(epithioethyl)phenyl ...4,4'-bis(epithioethyl)biphenyl, 4,4'-bis(epithioethyl)biphenyl, 4,4'-bis(epithioethyl)biphenyl, 4,4'-bis(epithioethyl)biphenyl, 4,4'-bis(epithioethyl)biphenyl, 4,4'-bis(epithioethyl)biphenyl, 4,4'-bis(epithioethyl)biphenyl, 4,4'-bis(epithioethyl)biphenyl, 4,4'-bis(epithioethyl)biphenyl, 4,4'-bis(epi (epithiopropyloxy)benzene, 1,3-bis(epithiopropyloxymethyl)benzene, 1,4-bis(epithiopropyloxymethyl)benzene, bis[4-(epithiopropyloxy)phenyl]methane, 2,2-bis[4-(epithiopropyloxy)phenyl]propane, bis[4-(4-epithiopropyloxy)phenyl]sulfide, bis[4-(epithiopropyloxy)phenyl]sulfone, and 4,4'-bis(epithiopropyloxy)biphenyl.

[0043] Examples of commercially available aromatic epoxy compounds from which similar thiiranes (A1) can be obtained include products sold under the trade names Epikote Resin 828 LVEL, Epikote Resin 166, and Epikote Resin 169 by Hexion Specialty Chemicals BV in the Netherlands, and products sold under the trade names EPICLONT™ 840, 840-S, 850, 850-S, EXA850CRP, and 850-LC by DIC Corporation in Japan.

[0044] Examples of difunctional or higher functional aliphatic thiiranes (A1) include 1,1-bis(epithioethyl)methane, 1,1-bis(epithiopropyl)methane, 1,2-bis(epithiopropyl)ethane, 1,3-bis(epithiopropyl)propane, 1,4-bis(epithiopropyl)butane, tetrakis(epithiopropyl)methane, 1,1,1-tris(epithiopropyl)propane, 1,3-bis(epithiopropyl)-1-(epithiopropyl)-2-thiapropane, and 1,5-bis(epithiopropyl)-2,4-bis(epithiopropyl). Bis(epithiopropyl)-3-thiapentane, bis(epithiopropyl) ether, bis(epithiopropyloxy)methane, 1,2-bis(epithiopropyloxy)ethane, 1,3-bis(epithiopropyloxy)propane, 1,2-bis(epithiopropyloxy)propane, 1-(epithiopropyloxy)-2-(epithiopropyloxymethyl)propane, 1,4-bis(epithiopropyloxy)butane, 1,3-bis(epithiopropyloxy)butane, 1-(epithiopropyloxy)-3-(epithiopropyloxymethyl)butane hexane, 1,5-bis(epithiopropyloxy)pentane, 1-(epithiopropyloxy)-4-(epithiopropyloxymethyl)pentane, 1,6-bis(epithiopropyloxy)hexane, 1-(epithiopropyloxy)-5-(epithiopropyloxymethyl)hexane, 1-(epithiopropyloxy)-2-[(2-(epithiopropyloxyethyl)oxy]ethane, 1-(epithiopropyloxy)-2-[[2-(2-epithiopropyloxyethyl)oxyethyl]oxy]ethane, tetrakis([epithiopropyl (epithiopropyloxymethyl)methane, 1,1,1-tris([epithiopropyloxymethyl)propane, 1,5-bis(epithiopropyloxy)-2-(epithiopropyloxymethyl)-3-thiapentane, 1,5-bis(epithiopropyloxy)-2,4-bis(epithiopropyloxymethyl)-3-thiapentane, 1-(epithiopropyloxy)-2,2-bis(epithiopropyloxymethyl)-4-thiahexane, 1,5,6-tris(epithiopropyloxy)-4-(epithiopropyloxymethyl)-3-thiahexane, 1,8-Bis(epithiopropyloxy)-4-(epithiopropyloxymethyl)-3,6-dithiaoctane, 1,8-bis(epithiopropyloxy)-4,5-bis(epithiopropyloxymethyl)-3,6-dithiaoctane, 1,8-bis(epithiopropyloxy)-4,4-bis(epithiopropyloxymethyl)-3,6-dithiaoctane, 1,8-bis(epithiopropyloxy)-2,4,5-tris(epithiopropyloxymethyl)-3,6-dithiaoctane, 1,8-bis(epithiopropyloxy)-2,5-bis(epithiopropyloxymethyl)-3,6-dithiaoctane, 1,9-bis(epithiopropyloxy)-5-([epithiopropyloxymethyl)-5-[(2-epithiopropyloxyethyl)oxymethyl]oxymethyl These include 1,10-bis(epithiopropyloxy)-5,6-bis[(2-epithiopropyloxyethyl)oxy]-3,6,9-trithiadecane, 1,11-bis([epithiopropyloxy)-4,8-bis(epithiopropyloxymethyl)-3,6,9-trithiaundecane, 1,11-bis(epithiopropyloxy)-5,7-bis(epithiopropyloxymethyl)-3,6,9-trithiaundecane, 1,11-bis(epithiopropyloxy)-5,7-[(2-[epithiopropyloxyethyl)oxymethyl)-3,6,9-trithiaundecane, and 1,11-bis(epithiopropyloxy)-4,7-bis(epithiopropyloxymethyl)-3,6,9-trithiaundecane.

[0045] Examples of commercially available difunctional or higher functionality aliphatic epoxy compounds from which analogous thiiranes (A1) can be obtained include products sold under the trade names iPox RD21, iPox CL60, iPox CL9 by ipox Chemicals GmbH, products sold under the trade name YED-216 D by Mitsubishi Chemical Corporation of Japan, products sold under the trade name Heloxy Modifier HD by Hexion, or products sold under the trade name Araldite DY 3601 by Huntsman.

[0046] Examples of difunctional or higher functional alicyclic thiiranes (A1) include 1,3-bis(epithioethyl)cyclohexane, 1,4-bis(epithioethyl)cyclohexane, bis[4-(epithioethyl)cyclohexyl]methane, bis[4-(epithiopropyl)cyclohexyl]methane, 2,2-bis[4-(epithioethyl)cyclohexyl]propane, bis[4-(epithiopropyl)cyclohexyl]sulfide, bis[4-(epithioethyl)cyclohexyl]sulfide, 2,5-bis(epithioethyl)-1,4-dithiane, 2,5-bis(epithiopropyl)-1,4-dithiane, 4-epithioethyl-1,2-cyclohexene sulfide, 4-epoxy-1,2-cyclohexene sulfide, 1,3- Included are bis(epithiopropyloxy)cyclohexane, 1,4-bis(epithiopropyloxy)cyclohexane, 1,3-bis(epithiopropyloxymethyl)cyclohexane, 1,4-bis(epithiopropyloxymethyl)cyclohexane, bis[4-(epithiopropyloxy)cyclohexyl]methane, 2,2-bis[4-(epithiopropyloxy)cyclohexyl]propane, bis[4-(epithiopropyloxy)cyclohexyl]sulfide, 2,5-bis(epithiopropyloxymethyl)-1,4-dithiane, and 2,5-bis(epithiopropyloxyethyloxymethyl)-1,4-dithiane, and isomers of dicyclopentadiene dimethanol bis-epithiopropyl ether.

[0047] Examples of commercially available cycloaliphatic epoxy compounds from which similar thiiranes (A1) can be obtained include products sold under the trade names CELLOXIDE 2021P and CELLOXIDE 8000 by Daicel Corporation of Japan, products sold under the trade names Omnilane 1005, Omnilane 2005, and Omnilane OC 3005 by IGM Resins BV, products sold under the trade name Syna Epoxy 21 by Jiangsu Tetra New Material Technology Co. Ltd., and products sold under the trade names THI-DE, DE-102, and DE-103 by ENEOS Corporation.

[0048] Examples of (A1) also include compounds obtained by substituting at least one hydrogen atom of an ethylene sulfide group with an optionally substituted alkyl or aryl group, for example, by substituting at least one hydrogen atom of an ethylene sulfide group with a methyl group.

[0049] Ingredient (A2): Thietanes In the composition according to the present invention, thietanes (A2) can also be used as the thioether compound of component (A).

[0050] For example, it can be prepared by reacting appropriate precursor compounds such as thietan-3-one, 3-thiethanol, 3-mercaptothietane, or 3-chlorothietane.

[0051] Difunctional or higher functional thietanes (A2) can also be used advantageously in the compositions according to the invention.

[0052] Also possible is a combination of a thiirane group and a thietane group.

[0053] Exemplary thietane syntheses are described in U.S. Patent Nos. 8,362,280 and 7,132,501. The thietanes described therein are further suitable as thietane (A2) in the compositions of the present invention.

[0054] For example, suitable thietanes (A2) include 3,3'-[oxybis(methylene)]bis(3-ethylthietane), 3-[(allyloxy)methyl]-3-ethylthietane, 3-ethyl-3-(phenoxymethyl)thietane, (3-ethylthietan-3-yl)methanol, 1,4-bis{[(3-ethylthietan-3-yl)methoxy]methyl}benzene, and 3-ethyl-3-{[(2-ethylhexyl)oxy]methyl}thietane.

[0055] Examples of commercially available oxetanes from which similar thietanes (A2) can be obtained include bis(1-ethyl-3-oxetanylmethyl)ether (DOX), 3-allyloxymethyl-3-ethyloxetane (AQX), 3-ethyl-3-(phenoxymethyl)oxetane (POX), 3-ethyl-3-hydroxymethyloxetane (OXA), 1,4-bis[(3-ethyl-3-oxetanylmethoxy)methyl]benzene (XDO), and 3-ethyl-3-[(2-ethylhexyloxy)methyl]oxetane (EHOX). These oxetanes are commercially available from Toagosei Co., Ltd.

[0056] The proportion of the thietane (A2) in component (A) is preferably in the range of 0 to 80% by weight, particularly preferably 0 to 50% by weight, based on the total weight of component (A).

[0057] Ingredient (A3): Hybrid compound Furthermore, component (A) can comprise a hybrid compound (A3) which, apart from at least one cyclic thioether group, further has a crosslinkable functional group such as a (meth)acrylate group, an isocyanate group, an oxetane group, a hydroxy group, or an epoxide.

[0058] In particular, the hybrid compound (A3) has at least one thiirane and / or thietane group as a cyclic thioether group.

[0059] For example, the hybrid compound (A3) can be obtained by partially reacting an at least bifunctional cyclic thioether with a compound bearing another group capable of crosslinking by addition.

[0060] Another possibility is the reaction of isocyanato(meth)acrylates with compounds which, apart from the thiirane and / or thietane groups, have isocyanate-reactive groups.

[0061] It is also possible to react hybrid functional epoxides and / or oxiranes to form analogous thiiranes and / or thietanes, and to partially replace the oxygen of at least difunctional epoxides or oxiranes with sulfur.

[0062] Preferably, the hybrid compound (A3) comprises, apart from at least one cyclic thioether group, further radically curable groups. In particular, thiirane(meth)acrylate hybrid compounds fall within the scope of the present invention.

[0063] Examples of commercially available epoxy (meth)acrylates from which similar thiiranes can be obtained include CYCLOMER M100 from Daicel, UVACURE 1561 from UCB, Epoxy Acrylat Solmer SE 1605, Miramer PE210HA from Miwon Europe GmbH, and Solmer PSE 1924 from Soltech Ltd. Oxetane (meth)acrylates such as Eternacoll OXMA from UBE Industries LTD can also be used to synthesize the hybrid compound (A3).

[0064] The presence of the hybrid compound (A3) makes the composition further crosslinkable. Further curing methods that can proceed apart from the polyinsertion reaction are radical, cationic or anionic polymerization, addition polymerization, and condensation polymerization.

[0065] Preferably, the proportion of the hybrid compound (A3) in component (A) is in the range of 0 to 90% by weight, particularly preferably 0 to 50% by weight, based on the total weight of component (A).

[0066] Component (B): Initiator Apart from the thioether (A), the composition according to the invention comprises at least one initiator (B) containing a functional group suitable for poly-insertion of component (A).

[0067] The use of at least difunctional cyclic thioethers in combination with initiator (B) is essential to the present invention and results in branched polymer chains.

[0068] In a broad sense, the initiator (B) is characterized in that, upon insertion of the thioether compound (A), a functional group suitable for polymerization maintains its structure and can undergo further insertion.

[0069] Preferred initiators (B) are all compounds containing a (thio)carbonylthio group. Compounds containing a (thio)carbonylthio group include all compounds containing a dithioester group (thiocarbonylthio group) or a thioacid ester group (carbonylthio group). There are no further structural limitations. The (thio)carbonylthio group can be linear, cyclic, or bridged, and can be present in prepolymers and / or oligomers.

[0070] The essential functional group of initiator (B) is a (thio)carbonylthio group. Without being bound by scientific theory, the successful mechanism of the reaction of such initiator (B) with cyclic thioethers is due to the fact that the (thio)carbonyl-sulfur bond is cleaved by the attack of the thiolate anion generated from the cyclic thioether. At the same time, a new (thio)carbonyl-sulfur bond is formed, allowing the monomer to be inserted. In this way, the central functional unit is maintained and can be used to insert another monomer selected from component (A).

[0071] In the sense of the present invention, suitable initiators (B) are derived, for example, from thioate esters, dithioesters, dithiocarbonates (xanthates), trithiocarbonates, and sulfur-bridged thiourethanes, including thiourethanes and dithiourethanes (dithiocarbamates).

[0072] Preferably, the initiator (B) is a cyclic initiator (B1).

[0073] Suitable cyclic compounds as cyclic initiator (B1) include γ-thiobutyrolactone, 2,4-thiazolidinedione, 2-thioxothiazolidin-4-one (rhodanine), and rhodanines substituted with aliphatic or aromatic groups, such as 3-ethyl-2-thioxothiazolidin-4-one or 3-benzyl-2-thioxothiazolidin-4-one.

[0074] Preferably, the cyclic initiator (B1) is a 2,4-thiazolidinedione.

[0075] In addition to the cyclic initiators (B1), linear initiators (B2) can also be used in the compositions according to the invention. Suitable examples include dibenzyltrithiocarbonate, S,S'-dimethyldithiocarbonate, S-butylbenzoylcarbamothioate, or 1,3,5-tris(3-acetylmercaptopropyl)-1,3,5-triazine-2,4,6-trione.

[0076] By choosing different initiators (B), it is possible to control, on the one hand, the curing rate of the liquid composition and, on the other hand, the mechanical properties of the cured composition.

[0077] When a linear initiator (B2) is used together with a thioether compound (A), a polythioether chain is formed as the initiator molecule extends.

[0078] The use of cyclic initiators (B1) leads to the formation of macrocyclic polythioether structures. As with linear initiators (B2), the degree of crosslinking of the cyclic polythioethers can be controlled by the proportion of at least difunctional cyclic thioethers.

[0079] The degree of crosslinking can be adjusted over a wide range by selecting the appropriate amount of at least difunctional cyclic thioether, thereby defining a comprehensive spectrum of properties.

[0080] Both the sparsely branched and heavily branched polythioethers are suitable for use as adhesives, casting materials, and coating materials in the cured state.

[0081] In terms of curing speed, the use of cyclic initiators (B1) is preferred over linear initiators (B2), with cyclic initiators (B1) providing higher curing speeds than linear initiators (B2).

[0082] The use of initiators (B) having more than one (thio)carbonylthio group is also within the scope of the present invention. In particular, difunctional or higher functionality initiators offer the possibility of advantageously controlling the reactivity of the mass and adjusting the flexibility of the cured mass.

[0083] Furthermore, an initiator (B) containing (thio)carbonylthio groups in a non-cyclic arrangement in addition to the (thio)carbonylthio groups in a cyclic arrangement in the same molecule can also be advantageously used. Such a compound can be considered as a combination of a cyclic initiator (B1) and a linear initiator (B2).

[0084] The present invention also encompasses the use of mixed-functional initiators (B3). In addition to at least one (thio)carbonylthio group, such initiators preferably contain other curable functional groups. Thus, for example, (meth)acrylate-functional initiators (B3) are also encompassed by the present invention.

[0085] By adding a photoinitiator for radical polymerization together with the (meth)acrylate-functional initiator (B3), more photofixable masses can be obtained.

[0086] Furthermore, the initiator (B) can be an oligomeric thioether compound (B4) when it has a (thio)carbonylthio group.

[0087] The use of oligomeric thioether compounds (B4) allows, in particular, the adjustment of the mechanical and adhesive properties of the cured composition, and in principle, the use of oligomeric thioether compounds (B) also allows the formation of more complex polymer structures, such as block copolymers.

[0088] Such oligomeric thioether compounds (B4) can be obtained by prepolymerization: for this purpose, initiator (B) is reacted with thioether compound (A) in a suitable equivalent ratio, so that the compounds involved in the reaction can then be further polymerized into the cured state.

[0089] For this purpose, preferably 1 to 50 equivalents, particularly preferably 2 to 40 equivalents, of the thioether compound (A) are reacted with 1 equivalent of the initiator (B).

[0090] Hereinafter and throughout this specification, the number of functional groups required for each reaction in each component is referred to as "equivalents." Thus, an equivalent of thioether compound (A) refers to each thioether group in the thioether compound, and an equivalent of initiator (B) refers to a functional group that is suitable for polymerization by insertion of thioether compound (A), maintains its structure, and can thereby undergo further insertion, preferably a (thio)carbonylthio group in initiator (B).

[0091] A plurality of "equivalents" is not further limited and includes both compounds having more than one functional group in the molecule and compounds having one functional group, and / or mixtures thereof.

[0092] Preferably, the oligomerized thioether compound (B4) is present in the liquid state.

[0093] Additionally, the ring size and / or chain length of the polythioether can be influenced by the equivalent ratio of (A) to (B).

[0094] Preferably, the thioether compound (A) can be used in a proportion of 5 to 300 equivalents, more preferably 8 to 250 equivalents, and particularly preferably 10 to 200 equivalents, based on 1 equivalent of the functional group of the initiator (B).

[0095] Based on the total weight of the mass excluding additives, component (B) is preferably present in a proportion of 0.1% to 20% by weight, particularly preferably 0.3% to 10% by weight.

[0096] Component (C): Catalyst Apart from the thioether compound (A) and the initiator (B), the composition further comprises at least one catalyst (C), which accelerates the polymerization and makes it possible to adjust the curing temperature of the composition.

[0097] The catalyst (C) may be selected from the group of non-ionic compounds (C1), such as Lewis acid-base adducts, and ionic compounds (C2), including ionic liquids and zwitterionic compounds.

[0098] Examples of non-ionic catalysts (C1) include adducts of borane and boron trihalides with diethyl ether, tetrahydrofuran, or dimethyl sulfide.

[0099] Zwitterionic compounds suitable as catalysts (C2) include, for example, betaine, amino acids, or carnitine.

[0100] Furthermore, suitable catalysts (C2) can be selected from the group comprising quaternary ammonium salts, quaternary phosphonium salts, tertiary sulfonium salts, and / or secondary iodonium salts. In the use of quaternary ammonium salts, tetramethylammonium, tetraethylammonium, tetra-n-butylammonium, tetra-n-hexylammonium, tetra-n-octylammonium, trimethyl-n-octylammonium, trimethylbenzylammonium, triethyl-n-octylammonium, triethylbenzylammonium, tri-n-butyl-n-octylammonium, tri-n-butylbenzylammonium, methyltriphenylammonium, ethyltriphenylammonium, n-butyltriphenylammonium, n-butyltriphenylammonium, 1-methylpyridinium ... Ethylpyridinium, 1-n-butylpyridinium, 1-n-hexylpyridinium, 1-n-octylpyridinium, 1-butyl-3-methylpyridinium, 1-n-dodecylpyridinium, 1-n-phenylpyridinium, 1-butyl-1-methylpyrrolidinium, 1-methylpicolinium, 1-ethylpicolinium, 1-n-butylpicolinium, 1-n-hexylpicolinium, 1-n-octylpicolinium, 1-n-dodecylpicolinium, 1-phenylpicolinium, 1-ethyl-3-methylimidazolium, 1-butyl-2,3-dimethylimidazolium, and 1-hexyl-3-methylimidazolium are preferred.

[0101] As catalyst (C2), it is particularly preferred to use an ammonium salt obtained by formally alkylating an amine.

[0102] Possible counterions include trifluoromethanesulfonate, p-toluenesulfonate, p-nitrophenoxide, hydrogensulfate, phosphate, hexafluorophosphate, thiocyanate, salicylate, acetate, propionate, hexanoate, 2-ethylhexanoate, tetrafluoroborate, tetrakis(pentafluorophenyl)borate, tetraphenylborate, hydroxide, or halide.

[0103] Examples of suitable catalysts include tetramethylammonium chloride, tetramethylammonium bromide, tetramethylammonium acetate, tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium acetate, tetra-n-butylammonium fluoride, tetra-n-butylammonium chloride, tetra-n-butylammonium bromide, tetra-n-butylammonium iodide, tetra-n-butylammonium acetate, tetra-n-butylammonium boron hydride, tetra-n-butylammonium hexafluorophosphate, tetra-n-butylammonium hydrogen sulfate, tetra-n-butylammonium tetrafluoroborate, tetra-n-butylammonium tetraphenylborate, tetra-n-butylammonium-p-toluenesulfonate, tetra-n-butylammonium salicylate, tetra-n-hexylammonium chloride, tetra-n-hexylammonium bromide, tetra-n-butylammonium acetate, tetra-n-butylammonium iodide, tetra-n-butylammonium hexafluorophosphate, tetra-n-butylammonium hydrogen sulfate, tetra-n-butylammonium tetrafluoroborate, tetra-n-butylammonium tetraphenylborate, tetra-n-butylammonium-p-toluenesulfonate, tetra-n-butylammonium salicylate, tetra-n-hexylammonium chloride, tetra-n-hexylammonium bromide, tetra-n-butylammonium acetate, tetra-n-butylammonium hexafluorophosphate ... xylammonium, tetra-n-octylammonium chloride, tetra-n-octylammonium bromide, tetra-n-octylammonium acetate, trimethyl-n-octylammonium chloride, trimethylbenzylammonium chloride, trimethylbenzylammonium bromide, triethyl-n-octylammonium chloride, triethylbenzylammonium chloride, triethylbenzylammonium bromide, tri-n-butyl-n-octylammonium chloride, tri-n-butylbenzylammonium fluoride, tri-n-butylbenzylammonium chloride, tri-n-butylbenzylammonium bromide, tri-n-butylbenzylammonium iodide, methyltriphenylammonium chloride, methyltriphenylammonium bromide, ethyltriphenylammonium chloride, ethyltriphenylammonium bromide, n-butyltriphenylammonium chloride, n-butyltriphenylammonium bromide, 1-butyl-2-chloride3-Dimethylimidazolium, 1-butyl-1-methylpyrrolidinium chloride, 1-butyl-3-methylpyridinium chloride, 1-methylpyridinium chloride, 1-methylpyridinium bromide, 1-ethylpyridinium chloride, 1-ethylpyridinium bromide, 1-n-butylpyridinium chloride, 1-n-butylpyridinium bromide, 1-n-hexylpyridinium chloride, 1-n-hexylpyridinium bromide, 1-n-octylpyridinium chloride, 1-n-octylpyridinium bromide, 1-n-dodecylpyridinium chloride, 1-n-dodecylpyridinium bromide, 1-n-phenyl chloride Examples of picolinium chloride include 1-n-phenylpyridinium bromide, 1-methylpicolinium chloride, 1-methylpicolinium bromide, 1-ethylpicolinium chloride, 1-ethylpicolinium bromide, 1-n-butylpicolinium chloride, 1-n-butylpicolinium bromide, 1-n-hexylpicolinium chloride, 1-n-hexylpicolinium bromide, 1-n-octylpicolinium chloride, 1-n-octylpicolinium bromide, 1-n-dodecylpicolinium chloride, 1-n-dodecylpicolinium bromide, 1-phenylpicolinium chloride, and 1-phenylpicolinium bromide.

[0104] Examples of quaternary phosphonium salts include tetramethylphosphonium chloride, tetramethylphosphonium bromide, tetraethylphosphonium chloride, tetraethylphosphonium bromide, tetra-n-butylphosphonium chloride, tetra-n-butylphosphonium bromide, tetra-n-butylphosphonium iodide, tetra-n-hexylphosphonium bromide, tetra-n-octylphosphonium bromide, methyltriphenylphosphonium bromide, methyltriphenylphosphonium iodide, ethyltriphenylphosphonium bromide, ethyltriphenylphosphonium iodide, n-butyltriphenylphosphonium bromide, n-butyltriphenylphosphonium iodide, n-hexyltriphenylphosphonium bromide, n-octyltriphenylphosphonium bromide, tetraphenylphosphonium bromide, tetrakishydroxymethylphosphonium chloride, tetrakishydroxymethylphosphonium bromide, tetrakishydroxyethylphosphonium chloride, and tetrakishydroxybutylphosphonium chloride.

[0105] Examples of tertiary sulfonium salts include trimethylsulfonium bromide, triethylsulfonium bromide, tri-n-butylsulfonium chloride, tri-n-butylsulfonium bromide, tri-n-butylsulfonium iodide, tri-n-butylsulfonium tetrafluoroborate, tri-n-hexylsulfonium bromide, tri-n-octylsulfonium bromide, triphenylsulfonium chloride, triphenylsulfonium bromide, and triphenylsulfonium iodide.

[0106] Examples of secondary iodonium salts include diphenyliodonium chloride, diphenyliodonium bromide, and diphenyliodonium iodide.

[0107] The catalyst (C) can be a single compound or a combination of compounds.

[0108] Based on the total weight of the mass excluding additives, component (C) is preferably present in a proportion of 0.01% to 10% by weight, particularly preferably in a proportion of 0.02% to 5% by weight.

[0109] Preferably, the catalyst (C) is used in a ratio of 0.001 to 10 equivalents, particularly preferably 0.005 to 5 equivalents, based on 1 equivalent of the functional group of the initiator (B).

[0110] The absence of a halogen-containing catalyst (C) can be advantageous for use in the electronics field.

[0111] Component (D): Radical curing compound Optionally, the composition according to the present invention further contains, in addition to components (A) to (C), a radically curable compound that can be radically polymerized by irradiation with actinic radiation or heat input.

[0112] Preferably, the radical curing compound (D) is a compound based on (meth)acrylate and (meth)acrylamide.There is no further restriction on the chemical structure of these compounds.For example, both aliphatic and aromatic (meth)acrylate and (meth)acrylamide can be used.

[0113] Herein and hereinafter, derivatives of acrylic acid and methacrylic acid, as well as combinations and mixtures thereof, are referred to as (meth)acrylates and (meth)acrylamides.

[0114] The radically curable compound (D) can be used to achieve rapid photofixation by irradiating the composition with actinic radiation.

[0115] Furthermore, the radically curable compounds (D) can be used to favorably influence the dosing properties of the curable mass.

[0116] Preferably, the radically curable compound (D) comprises at least one difunctional compound.

[0117] For example, the following radically curable compounds (D) are suitable: isobornyl acrylate, stearyl acrylate, tetrahydrofurfuryl acrylate, cyclohexyl acrylate, 3,3,5-trimethylcyclohexanol acrylate, behenyl acrylate, 2-methoxyethyl acrylate and other singly or severally alkoxylated alkyl acrylates, isobutyl acrylate, isooctyl acrylate, lauryl acrylate, tridecyl acrylate, isostearyl acrylate, 2-(o-phenylphenoxy)ethyl acrylate, acryloylmorpholine, N,N-dimethylacrylamide, 4-butanediol diacrylate, 1,6- Hexanediol diacrylate, 1,10-decanediol diacrylate, tricyclodecane dimethanol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, polybutadiene diacrylate, cyclohexanedimethanol diacrylate, monomeric diacrylates and diurethane acrylates, oligomeric or polymeric diols and polyols, polytetramethylene ethylene glycol dimethacrylate, trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate (TMPTMA), dipentaerythritol hexaacrylate (DPHA), and combinations thereof. Higher functionality acrylates derived from multi-branched or dendrimeric alcohols can be advantageously used.

[0118] Analogous methacrylates are also within the scope of this invention.

[0119] Furthermore, radically curable compounds (D) having allyl groups, such as 1,3,5-triallyl-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, commercially available under the trademark TAICROS®, are also suitable. Non-hydrogenated polybutadienes having free double bonds, such as Poly BD® types, can also be used as radically curable compounds (D).

[0120] Acrylates and urethane acrylates based on polyesters, polyethers, polycarbonate diols, polybutadiene diols, and / or hydrogenated polybutadiene diols can be used as a higher molecular mass radically curable compound (D) (component D).

[0121] Furthermore, a combination of a plurality of radically curable compounds (D) is also included within the scope of the present invention.

[0122] In the compositions according to the invention, the radically curable compounds (D) are preferably present in a proportion of up to 50% by weight, particularly preferably up to 30% by weight, based on the total weight of the composition excluding additives.

[0123] Component (E): Radical polymerization initiator Apart from the components (A) to (D), the composition optionally contains a further initiator (E) for activating the radical polymerization, preferably a photoinitiator (E1).

[0124] As the photoinitiator (E1), conventional commercially available compounds such as α-hydroxyketone, benzophenone, α,α'-diethoxyacetophenone, 4,4-diethylaminobenzophenone, 2,2-dimethoxy-2-phenylacetophenone, 4-isopropylphenyl-2-hydroxy-2-propylketone, 1-hydroxycyclohexylphenylketone, isoamyl-p-dimethylaminobenzoate, methyl-4-dimethylaminobenzoate, methyl-o-benzoylbenzoate, benzoin, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2-isopropylthioxanthone, dibenzosuberone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and bisacylphosphine oxide can be used. The listed photoinitiators can be used alone or in combination of two or more of the listed compounds.

[0125] As the UV photoinitiator (E1) used in radical polymerization, for example, IRGACURE™ type from BASF SE can be used, such as IRGACURE 184, IRGACURE 500, IRGACURE 1179, IRGACURE 2959, IRGACURE 745, IRGACURE 651, IRGACURE 369, IRGACURE 907, IRGACURE 1300, IRGACURE 819, IRGACURE 819DW, IRGACURE 2022, IRGACURE 2100, IRGACURE 784, IRGACURE 250, IRGACURE TPO, and IRGACURE TPO-L types.

[0126] Additionally, DAROCUR® types from BASF SE can be used, such as DAROCUR MBF, DAROCUR 1173, DAROCUR TPO, and DAROCUR 4265 types.

[0127] In the composition according to the present invention, the photoinitiator (E1) used as component (E) is activatable by irradiation with actinic radiation, preferably at a wavelength of 200 nm to 480 nm, particularly preferably 250 nm to 400 nm.

[0128] In the composition according to the invention, the initiator (E) used to activate the radical polymerization is preferably present in a proportion of 0% to 5% by weight, particularly preferably 0.01% to 3% by weight, based on the total weight of the mass excluding additives.

[0129] Furthermore, the initiator (E) for radical polymerization may comprise a thermal initiator (E2) that can be activated by heating up to a certain temperature.

[0130] The thermal initiator (E2) ensures complete curing of the radically curable compound (D).

[0131] The present invention also encompasses pure heat curing of the radically curable component (D), in which case the radical polymerization initiator (E) may be composed of component (E2).

[0132] Preferably, the additional thermal initiator (E2) comprises one or more peroxo compounds, which may be selected, for example, from the group consisting of peroxo(di)esters, hydroperoxides, (di)alkyl peroxides, ketone peroxides, perketals, peracids, peroxomonocarbonates, and peroxodicarbonates. It is also possible to use thermal initiators (E2) selected from the group consisting of azo compounds or benzopinacols.

[0133] In the compositions according to the invention, the thermal initiator (E2) is present in a proportion of up to 100% by weight, preferably in a proportion of up to 90% by weight, more preferably in a proportion of up to 80% by weight, particularly preferably in a proportion of up to 70% by weight, based on component (E).

[0134] Ingredient (F): Additive Additionally, the described compositions may include an aerobic component as additive (F).

[0135] The additive (F) is preferably selected from the group consisting of solvents, fillers, dyes, pigments, antioxidants, fluorescent agents, sensitizers, accelerators, stabilizers, adhesion promoters, drying agents, crosslinking agents, flow improvers, wetting agents, thixotropic agents, non-reactive softeners, non-reactive polymeric thickeners, flame retardants, corrosion inhibitors, plasticizers, and combinations thereof.

[0136] For example, epoxides can be used as accelerators, adding them to accelerate cure and lower the temperature required for cure.

[0137] The composition according to the present invention can contain one or more addition-crosslinking curing agents for component (A) as additive (F) as a crosslinking agent. The chemical nature of the curing agent is not further limited. Examples of additional addition-crosslinking curing agents include compounds such as thiols, anhydrides, amines, and / or polyols.

[0138] Preferably, the cross-linking agent is at least difunctional.

[0139] In the composition according to the invention, additive (F) is preferably present in a proportion of up to 85% by weight, based on the total weight of the composition including all ingredients.

[0140] Formulation of the composition of the present invention In a first preferred embodiment, the composition comprises or consists of: a) 15% to 99% by weight of at least one thioether compound (A); b) 0.1 wt% to 20 wt% of an initiator (B); and c) 0.01 wt% to 10 wt% of a catalyst (C) a) to c) are based on the total mass of components (A) to (C), respectively, and the proportions of components (A) to (C) total 100% by weight. In this embodiment, in particular, the composition does not include the above-mentioned components (D) and (E).

[0141] In a second preferred embodiment, the composition comprises or consists of: a) 15% to 99% by weight of at least one thioether compound (A); b) 0.1 wt% to 20 wt% of an initiator (B); c) 0.01 wt% to 10 wt% of a catalyst (C); d) 0% to 50% by weight of a radical curable compound (D); and e) 0% to 5% by weight of an initiator (E) for activating radical polymerization a) to e) are based on the total mass of components (A) to (E), respectively, and the proportions of components (A) to (E) total 100% by weight.

[0142] In either embodiment, the composition may preferably contain additive (F) in a proportion of up to 85% by weight, based on the total weight of the mass.

[0143] In an advantageous embodiment, the amount of solvent required to dissolve and / or disperse the components of the composition, in particular the initiator (B) and / or catalyst (C), can be reduced by using low-viscosity components in the composition. Radically curable compounds (D) are particularly suitable for this purpose.

[0144] In a preferred embodiment, the addition of a solvent can be omitted entirely. The term "solvent" refers to an inert solvent in the composition that does not participate in the polymerization reaction.

[0145] Hardening of the mass according to the invention At temperatures between 60°C and 130°C, the composition according to the present invention can be completely cured within 1 hour, preferably within 30 minutes.

[0146] Also included within the scope of the present invention are temperature gradient cure profiles, i.e., the cure temperature of each composition is changed at least once during cure, subject to inevitable variations.

[0147] For example, heating of the curable composition can be carried out in a convection oven, by thermode, IR radiator, laser, microwave, or induction.

[0148] The compositions of the present invention may have an induction period when each composition is cured at a temperature below its respective onset temperature. The induction period is characterized by the absence of measurable curing of the composition. This means that during the induction period (excluding unavoidable fluctuations), no significant reaction enthalpy can be measured by differential scanning calorimetry and / or viscosity increase by rheometer.

[0149] Depending on the constant temperature below the onset temperature, the induction period may last up to 30 minutes, for example 10 or 20 minutes.

[0150] In particular, the crosslinking reaction after the induction period proceeds at a rate that is almost independent of temperature.

[0151] The compositions according to the invention can also be formulated as preactivatable compositions, in which case the respective composition is activated for curing by an appropriate heat input, after which the heat source is removed, and after a predetermined waiting time the composition is cured.

[0152] Use of the composition according to the invention The compositions of the present invention are particularly suitable for bonding, casting, or coating substrates, and because they cure quickly at relatively low temperatures, they can be used on temperature-sensitive substrates.

[0153] The many possibilities for formulating the compositions according to the invention allow them to exhibit mechanical properties for a variety of applications, such as addition-cure adhesives, moisture-cure silicones, or radical-cure systems.

[0154] Due to the low reaction enthalpy during curing of the compositions according to the invention, the use of fillers can optionally be omitted.

[0155] During the induction period, the viscosity of the composition can be further reduced by a selected constant temperature, resulting in improved flow behavior. The corresponding composition is particularly suitable for casting small or complex shapes.

[0156] In particular, the induction period described above can be advantageously used to carry out application (or dose) and / or curing spatially and temporally separated from thermal activation without further energy input, which allows in particular the use of temperature-sensitive substrates as bonding partners, for example based on polycarbonate.

[0157] Methods for using the agglomerates according to the present invention A method for producing a component using such a curable composition preferably comprises the steps of: a) applying a composition to a first substrate; b) optionally adding a second substrate to form a composite substrate from the first substrate and the second substrate, and contacting the second substrate with the composition applied onto the first substrate; c) optionally exposing the composition to actinic radiation to achieve sufficient fixation strength for further processing of the first substrate or composite substrate; and d) heating the optionally irradiated composition on the first substrate or in the composite substrate to a predetermined cure temperature and curing to form a part, the part comprising the first substrate and a cured adhesive layer connected to the first substrate and optionally the second substrate.

[0158] After bonding in step b), the first or second substrate can be aligned with respect to the other substrate before fixing the composition by irradiation.

[0159] In a first preferred embodiment, the predetermined curing temperature is equal to or higher than the onset temperature of the composition, also known as the curing temperature. In this variant, the composition is in particular heated continuously until it cures.

[0160] In another preferred embodiment, the heating of the composition in step d) is carried out at a certain temperature, also known as the induction temperature, below the onset temperature of the composition, in a manner also known as thermal curing, in other words, the predetermined curing temperature is the induction temperature.

[0161] The induction temperature is preferably at most 30°C lower than the onset temperature, particularly preferably at most 20°C lower than the onset temperature.

[0162] Depending on the selected induction temperature, the inventive composition can have an induction time of up to 30 minutes without hardening. This hardening behavior allows the composition to have a long flow length without risking premature hardening of the part. In this way, the composition can be thermally preactivated.

[0163] In a third preferred embodiment, the heat curing in step d) is carried out below the onset temperature, with the heat source for heating the composition removed after a predetermined pre-activation time. After a predetermined waiting time, the composition is cured without the use of a heat source. In this way, the part can be subjected to any further processing steps and / or spatially separated processing before final curing.

[0164] Alternatively, instead of heating in a suitable vessel or reactor, the heat input for heat curing below the onset temperature can be a continuous flow. For example, applicators such as those used to apply hot melt adhesives are suitable for thermal preactivation of the compositions according to the invention.

[0165] In another preferred embodiment, the light-fixing step c) is carried out only after preactivation of the composition according to step d), an advantage of this method being that after preactivation and light-fixing, final curing of the composition occurs without the application of further heat.

[0166] Properties of the cured composition The compositions of the present invention are suitable for bonding, casting, and coating substrates. Numerous formulation methods allow for the definition of a wide range of property profiles.

[0167] The compositions of the present invention are liquid at room temperature and are preferably formulated as a single component.

[0168] The compositions of the present invention are curable to form solid, polymeric structures under the described cure conditions, and the tensile strength of the cured compositions is essentially maintained even after exposure to temperature and humidity.

[0169] If curing is carried out below the onset temperature, the composition exhibits an induction period of up to 30 minutes during which it remains fluid indefinitely, allowing for thermal preactivation of the composition.

[0170] Optional light fixation allows for high positional accuracy of the joined parts right up to the final curing, thus eliminating the need for traditional fixation aids, which are either not available or represent unacceptable additional costs, especially when processing miniaturized parts.

[0171] The ring-expansion polymerization curing mechanism allows thioether compounds, particularly thiiranes and thietanes, to be cured at low temperatures with sufficiently long processing times. The compositions exhibit sharp cure profiles and simultaneously low reaction enthalpies, allowing safe handling of low-viscosity formulations containing small amounts of fillers.

[0172] The reaction enthalpy is preferably less than 450 J / g, more preferably less than 300 J / g.

[0173] The polymer network formed during curing of the compositions according to the invention is highly resistant to temperature and media.

[0174] Furthermore, by using the hybrid compound (A3) and / or the mixed functionality initiator (B3), the polymer network and any further polymer network can be linked together based on thermal curing and photosetting.

[0175] The compressive shear strength of the glass or aluminum is preferably at least 1 MPa, particularly preferably at least 10 MPa.

[0176] A wide mechanical range can be accessed by adjusting the ring size and crosslink density. High strength yet very flexible materials can be formulated. The modulus of the cured composition can be tuned from 1 MPa to 10,000 MPa.

[0177] Further characteristics and features of the present invention will be illustrated and described in detail below with reference to preferred embodiments, which should not be construed as limiting.

[0178] Measurement methods and definitions used hardening "Crosslinking" or "curing" is defined as a polymerization, addition, or condensation reaction beyond the gel point, which is the point where the storage modulus G' equals the loss modulus G".

[0179] irradiation For irradiation, the composition according to the invention was irradiated with an LED lamp of the DELOLUX series manufactured by DELO Industrie Klebstoffe GmbH & Co. KGaA at a wavelength of 365 nm and an output of 200±20 mW / cm. 2 The irradiation was carried out at an intensity of .

[0180] room temperature The room temperature should be 23±2°C.

[0181] Viscosity measurement The viscosity was measured at 23° C. and a shear rate of 10 / s using an Anton Paar rheometer Physica MCR302 with standardized measuring cone CP20-1.

[0182] Tensile strength Tensile properties, including modulus, tensile strength, and elongation at break, were measured in accordance with DIN EN ISO 527-2:2012-06. Type 5A specimens were used. Measurements were performed at room temperature using a Zwick Roell Allround-Line 20 kN universal testing machine at a test speed of 1 mm / min. Curing was performed by light fixing, with 60-second exposures on each side, optionally with sample rotation after the first 60 seconds. Subsequent heat curing was performed for 45 minutes in a convection oven preheated to 100°C. After cooling, the cured composition specimens were demolded and conditioned at room temperature for 24 hours.

[0183] Compressive shear strength Two samples (20 mm x 20 mm x 5 mm) made of glass or laser-treated aluminum were glued together with a 5 mm overlap using the respective compositions. To do this, a bead of the respective composition was applied to the first sample and spread thinly. The second sample was then joined. The thickness and overlap of the adhesive layer of 0.1 mm were adjusted with a distance wire and / or adhesive device. Optionally, a 200 mW / cm 2 The bonded samples were irradiated for 60 seconds at a wavelength of 365 nm using a DELOLUX 20 / 365 LED lamp with an intensity of 100°C. Subsequent thermal curing was carried out for 45 minutes in a convection oven preheated to 100°C. The samples were conditioned at room temperature for 24 hours prior to measurement.

[0184] Thermal DSC measurement DSC measurements of reactivity were carried out on a differential scanning calorimeter (DSC) of type DSC2 or DSC3+ manufactured by Mettler Toledo.

[0185] For this purpose, 6 mg to 10 mg of liquid sample was weighed into an aluminum crucible (40 μL) using a pin, sealed with a lid, and measured at a temperature range of 30 °C to 230 °C and a heating rate of 5 K / min. Air was used as the process gas (flow rate of 30 mL / min).

[0186] The onset, reaction enthalpy, and peak temperature were evaluated.

[0187] The induction period was determined by isothermal DSC measurements at 80°C and subsequent dynamic DSC measurements in the temperature range from 23°C to 220°C and a heating rate of 10 K / min.

[0188] If curing takes place at 80° C. without a measurable induction period or if the induction period lasts more than 30 minutes, it may be necessary to adjust the temperature of the isothermal DSC measurement, e.g. by dynamic DSC measurement, respectively.

[0189] The onset (corresponding to the induction period), peak time, reaction enthalpy, reaction turnover number, and residual enthalpy were evaluated.

[0190] Optical DSC measurement DSC measurements of the radiation-induced curing reactivity were carried out using a dynamic differential scanning calorimeter (DSC) of the DSC3+ type manufactured by Mettler Toledo, whereby 6–10 mg of liquid sample was weighed into an aluminum crucible (40 μL) using a pin and exposed to 365 nm light for 10 min at 30 °C.

[0191] The peak time and reaction enthalpy were evaluated after subtracting the energy input from the LED lamp.

[0192] Preparation of the curable composition The liquid ingredients were mixed first, then possible fillers and optionally additional solids were mixed using a laboratory stirrer, laboratory dissolver, or Speedmixer (Hauschild) until a homogeneous composition was formed. Compositions containing photoinitiators and sensitive to visible light must be prepared using light outside the excitation wavelength of the photoinitiator or sensitizer, as appropriate.

[0193] The composition thus prepared was filled into a single-chamber cartridge and sealed.

[0194] The following list includes all compounds and their abbreviations used in the examples to prepare the curable compositions:

[0195] Component (A) Thioether compound (A1-1) Bifunctional thiirane based on hydrogenated bisphenol A (A1-2) Bisphenol F-based bifunctional thiirane (A1-3) Bisphenol A-based bifunctional thiirane (A1-4) Monofunctional Thiirane Based on 4-tert-Butylphenyl Glycidyl Ether (A1-5) Monofunctional thiirane based on 2-ethylhexyl glycidyl ether (A2-1) Monofunctional thietane based on trimethylolpropane monoallyl ether (A3-1) Hybrid compounds based on 4-hydroxybutyl acrylate glycidyl ether

[0196] Component (B): Initiator (B1-1) Cyclic initiator: 2,4-thiazolidinedione (available from TCI Deutschland GmbH) (B1-2) Cyclic initiator; rhodanine (available from TCI Deutschland GmbH) (B1-3) Cyclic initiator: 3-ethylrhodanine (available from TCI Deutschland GmbH) (B2-1) Linear initiator; reaction product of 1 equivalent of 2,2-(ethylenedioxy)diethanethiol and 2 equivalents of 2-isocyanatoethyl methacrylate (B2-2) Linear initiator; a reaction product of radical polymerization of dibenzyl trithiocarbonate and n-butyl acrylate, approximately M n = 2.700 g / mol.

[0197] Component (C): Catalyst (C2-1) Tetra-n-butylammonium chloride (available from TCI Deutschland GmbH) (C2-2) Tetra-n-butylammonium acetate (available from Sigma-Aldrich Chemie GmbH) (C2-3) Tetra-n-butylammonium salicylate (available from TCI Deutschland GmbH) (C2-4) 1-butyl-2,3-dimethylimidazolium chloride (available from TCI Deutschland GmbH)

[0198] Component (D): Radical curing compound (D1-1) 4-Acryloylmorpholine (available from RAHN GmbH) (D1-2) Trimethylolpropane trimethacrylate (available from ARKEMA FRANCE under the trade name Sartomer SR350D) (D1-3) Polytetramethylene ethylene glycol dimethacrylate (available from 3M Deutschland GmbH under the trade name DIOL-6000-DMA)

[0199] Component (E): Radical polymerization initiator (E1-1) 1-hydroxycyclohexyl phenyl ketone (available from IGM Resins BV under the trade name Omnirad 184) (E2-1)TBPND (available from United Initiators)

[0200] Ingredient (F): Additive (F1-1) Propylene carbonate (available from BCD Chemie GmbH) (F1-2) Cab-O-Sil TS 382 (available from Cabot) (F1-3) Denka fused silica FB-74 (available from Denki Kagaku Kogyo Co., Ltd.) (F1-4) Denka fused silica FB-7SDC (available from Denki Kagaku Kogyo Co., Ltd.) (F1-5) Denka fused silica SFP-30M (available from Denki Kagaku Kogyo Co., Ltd.) (F1-6) 3-glycidyloxypropyltrimethoxysilane (available from Evonik Nutrition & Care GmbH under the trade name Dynasylan GLYMO) (F1-7) 2,2,6,6-Tetramethylpiperidine-1-oxyl (available from Sigma-Aldrich Chemie GmbH under the trade name TEMPO) (F1-8)jER YX 8000D = hydrogenated bisphenol A epoxy resin (available from Mitsubishi Chemical)

[0201] [Table 1]

[0202] [Table 2]

[0203] [Table 3]

[0204] [Table 4]

[0205] The compositions of Examples 1-19 are illustrative and non-conclusive, showing the range of formulation possibilities of compositions according to the present invention. After curing, the compositions achieve a compressive shear strength of at least 1 MPa. The compositions of Examples 9-19 contain radically curable components and are further fixable with actinic radiation.

[0206] Examples according to the present invention exhibit consistently low reaction enthalpies of less than 300 J / g, which allows for safe handling of the compositions according to the present invention, for example, during manufacturing or transportation.

[0207] The examples according to the invention that make no mention of the cure time at 80°C or the induction period at 80°C require significantly higher temperatures for cure, and as a result, no relevant measurements could be obtained under the defined test conditions.

[0208] The compositions of Examples 1 to 3 each contain at least one difunctional cyclic thioether (A) in combination with an initiator (B) and a catalyst (C). At 80°C, the compositions cure within seconds to minutes after an induction period, achieving tensile strengths greater than 15 MPa.

[0209] The compositions of Examples 4 and 5 use different catalysts (C). These compositions exhibit mechanical properties comparable to those of Examples 1 to 3. The composition of Example 4 achieves an induction period of more than 20 minutes at 80°C.

[0210] Example 6 uses a catalyst based on an imidazolium salt, and Example 7 uses the cyclic initiator 3-ethylrhodanine.

[0211] The composition of Example 8 contains a lower amount of catalyst (C) than the other examples of the present invention. It is also possible to cure compositions containing these ingredients. The cured composition of Example 8 exhibits a high elongation at break of 16%.

[0212] The compositions of Examples 9 and 10 have an increased content of cyclic thioether (A) compared to the other examples according to the invention, and these variations have improved tensile strength and modulus.

[0213] Example 11 contains a high proportion of monofunctional thietanes in addition to difunctional thiiranes. This curable composition exhibits an induction period of 29.6 minutes and a relatively low reaction enthalpy of -108 J / g.

[0214] The compositions of Examples 12 to 24 each contain a radically curable compound (D) and a photoinitiator (E1). Example 12 shows a photofixable variant with a purely difunctional proportion of thioether compound (A). The composition of Example 14 further contains a thermal initiator (E2). The composition of Example 15 contains an increased amount of catalyst (C). Furthermore, this composition does not contain any solvent.

[0215] The composition of Example 16 contains rhodanine as a cyclic initiator (B). The composition of Example 17 contains a linear initiator (B). Both compositions achieve good tensile strength. The cure time of the formulation of Example 17 is significantly increased.

[0216] The composition according to Example 18 contains a proportion of epoxide in addition to the cyclic thioether (A). The use of epoxide as additive (F) in addition to the cyclic thioether can simultaneously promote curing at low temperatures. However, complete replacement of component (A) with epoxide is outside the scope of the present invention. The corresponding Comparative Example 26 shows that such a composition is not curable within the scope of the present invention.

[0217] The compositions of Examples 19 and 20 further comprise an adhesion promoter. The composition of Example 19 also comprises an additional additive (F), thus representing a total proportion of additive (F) of 66% by weight, based on the total weight of the composition. The reaction enthalpy of this mass is -58 J / g. Accordingly, the compositions of the present invention allow the formulation of highly filled systems that can be handled safely and still allow for excellent curing behavior and high tensile strength.

[0218] The composition according to Example 21 contains a smaller amount of cyclic thioether (A) and always has good mechanical properties. As the proportion of monofunctional cyclic thioether increases, as in the composition according to Example 22, the tensile strength decreases, but is still sufficiently high.

[0219] The composition according to Example 23 illustrates a combination of a linear initiator and a cyclic initiator (B) that may also be used according to the present invention.

[0220] In Example 24, a hybrid functional component was used. The combination of acrylate and thiirane functional groups allowed for the polymer network to be linked by photosetting and thermal curing, resulting in a cured composition with advantageous properties. The cured composition exhibited a high tensile strength of 48.3 MPa.

[0221] In Comparative Example 25, no catalyst (C) was added.

[0222] In Comparative Example 26, the thioether compound (A) was replaced with a difunctional glycidyl ether based on bisphenol A. Comparative Example 27 does not contain a difunctional thiirane (A1).

[0223] All of the comparative compositions are not curable within the meaning of the present invention.

[0224] According to the present invention, by combining at least one thioether compound (A) with an initiator (B) and a catalyst (C), it is possible to formulate agglomerates with a strictly defined temperature range and induction period for heat curing, as can be seen from the measurement data in Figures 1 and 2.

[0225] Figure 1 shows the DSC curve of the curable composition of Example 1 according to the present invention. Curing begins at 101°C and is carried out over a strictly limited temperature range. The peak temperature is 107°C and the reaction enthalpy is -182 J / g.

[0226] 2 shows an isothermal measurement of the curable composition of Example 1 according to the present invention, performed at a temperature of 80° C. No measurable cure occurs during the 10.6 minute induction period, after which rapid cure of the composition occurs over the 4.3 minute cure time.

Claims

1. 1. A curable composition that is liquid at room temperature, comprising: a) at least one thioether compound (A); b) at least one initiator (B), and c) at least one catalyst (C) Including, The composition, wherein the at least one thioether compound (A) comprises one at least difunctional cyclic thioether.

2. 2. The composition of claim 1, wherein the thioether compound (A) comprises one or more at least difunctional thiiranes (A1) and / or one or more at least difunctional thietanes (A2).

3. 3. The composition of claim 2, wherein the thioether compound (A) comprises a mixture of one or more at least difunctional thiiranes (A1) and one or more at least monofunctional thiiranes (A1).

4. The composition of any one of claims 1 to 3, wherein the initiator (B) comprises a (thio)carbonylthio group.

5. 5. The composition according to claim 4, wherein the initiator (B) is 2,4-thiazolidinedione or an oligomeric thioether compound (B4) prepared therefrom.

6. The composition according to any one of claims 1 to 5, wherein the thioether compound (A) is contained in the curable composition in a ratio of 5 to 300 equivalents based on 1 equivalent of the initiator (B).

7. The composition according to any one of claims 1 to 6, wherein the catalyst (C) is selected from the group consisting of quaternary ammonium salts, quaternary phosphonium salts, tertiary sulfonium salts, and / or secondary iodonium salts.

8. 8. The composition according to claim 1, wherein the catalyst (C) is contained in the curable mass in a ratio of 0.005 to 5 equivalents, based on 1 equivalent of the initiator (B).

9. The composition according to any one of claims 1 to 8, further comprising a radically curable compound (D) and / or an initiator for radical polymerization (E).

10. The composition comprises the following components: 15% to 99% by weight of said at least one thioether compound (A), 0.1% by weight to 20% by weight of said initiator (B), 0.01% by weight to 10% by weight of the catalyst (C), 0% to 50% by weight of a radically curable compound (D), and 0% to 5% by weight of an initiator (E) for activating radical polymerization Including, The composition according to any one of claims 1 to 9, wherein each of these is based on the total mass of components (A) to (E), and the total of the proportions of components (A) to (E) is 100% by weight.

11. 11. The composition of claim 10, wherein the mass comprises up to 85% by weight of the additive, based on the total weight of the mass including all ingredients.

12. Use of a composition according to any one of claims 1 to 11 for bonding, casting and / or coating substrates.

13. The use according to claim 12, wherein the substrate is an electronic or optoelectronic component.

14. 12. A method for manufacturing a part using the hardenable mass according to any one of claims 1 to 11, said method comprising the following steps: a) applying the composition to a first substrate; b) optionally, adding a second substrate when forming a composite substrate from the first substrate and the second substrate, and contacting the second substrate with the composition applied onto the first substrate; c) optionally exposing the composition to actinic radiation to achieve sufficient bond strength for further processing of the first substrate or the composite substrate; and d) heating the optionally irradiated composition on the first substrate or in the composite substrate to a predetermined curing temperature to cure and form a part. Including, The method, wherein the component comprises the first substrate and a cured adhesive layer connected to the first substrate and optionally to the second substrate.

15. 15. The method according to claim 14, wherein the heating in step d) is carried out at an induction temperature below the onset temperature of the composition, in particular the induction temperature being at most 30°C lower than the onset temperature.

16. 16. The method of claim 15, wherein a heat source for heating the composition is removed after a predetermined preactivation time, and curing of the composition occurs without the use of the heat source after a predetermined waiting time.

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