Curable composition comprising a polytrimethylene ether glycol and method using the composition

Abstract

An actinic radiation-curable composition comprises the following components: (A) a urethane (meth)acrylate based on hydroxy-functional polytrimethylene ether glycol (a1); (B) a (meth)acrylate monomer; and (C) a free-radical initiator component comprising a free-radical photoinitiator (c1). Component (A) is present in the curable composition in a proportion of at least 30% by weight in relation to the total weight of components (A) to (C). Furthermore, a method for bonding, potting, sealing and / or coating is specified.

Description

[0001] DELO Industrial Adhesives GmbH & Co. KGaA Our reference: D 3397 WO

[0002] WS / TH

[0003] Curable mass comprising a polytrimethylene ether glycol and a process using the mass

[0004] AREA OF INVENTION

[0005] The invention relates to an actinic radiation-curable mass comprising a urethane (meth)acrylate based on polytrimethylene ether glycol. Furthermore, the invention relates to a method for joining, potting, sealing, and / or coating using the mass.

[0006] TECHNICAL BACKGROUND

[0007] Light-curing compounds with high flexibility are particularly suitable as potting compounds and for bonding housings for electronic components. These adhesives can protect the components from media and temperature-related influences and have a shock-absorbing effect.

[0008] Highly flexible adhesives can be formulated using urethane (meth)acrylates based on polyethers. Polypropylene glycol (poly-1,2-propanediol, PPG) is frequently used as the starting material. However, the achievable adhesion values ​​on plastics such as polycarbonate (PC) are low. Better adhesion properties can be achieved with urethane (meth)acrylates based on polytetrahydrofuran (poly-THF), but at the cost of reduced peel strength. Urethane (meth)acrylates with a polycarbonate backbone exhibit good adhesion and peel strength; however, the cured compounds are less flexible and therefore not suitable for use in the aforementioned applications.

[0009] The functionalization of polyols with different backbones is known in the art. For example, (meth)acrylate-functionalized urethanes can be obtained directly by reacting the polyols with polyol-reactive (meth)acrylates. Isocyanate-functionalized (meth)acrylates are frequently used for this purpose. An alternative approach is the extension of polyols with difunctional isocyanates followed by capping with isocyanate-reactive (meth)acrylates, including hydroxy-functionalized or amine-functionalized (meth)acrylates. Examples of these syntheses can be found in JP 5 764 040 B2 or WO 2015 / 135800 A1.

[0010] US Patent 2023 / 0183411 A1 combines various (meth)acrylate-functional polyurethanes to form hard and soft segments. Polyether-based diols are used, which are extended with a difunctional isocyanate and finally functionalized with a (meth)acrylate. The cured materials exhibit good thermal resistance and toughness and are particularly suitable for use in 3D printing.

[0011] WO 2013 / 173976 A1 discloses transparent adhesives with a particularly low modulus of elasticity. The light-curable compounds comprise urethane acrylates with a polyether backbone and a plasticizer. The adhesives exhibit very high resistance and good optical properties.

[0012] Light-curable compounds based on (meth)acrylate-functional polyether urethanes, as disclosed in US 2022 / 0204809 A1, exhibit particularly good hydrolysis resistance. The formulations show low mass loss when the cured adhesives are exposed to acidic or alkaline aqueous media.

[0013] The compositions disclosed in the prior art have in common that the increased flexibility achieved through the use of polyether-based urethane (meth)acrylates comes at the expense of the adhesion properties and / or durability of the compositions.

[0014] There is therefore a continued need for actinic radiation-curable materials with excellent mechanical properties and high flexibility in the hardened state.

[0015] SUMMARY OF THE INVENTION

[0016] The object of the present invention is to provide actinic radiation-curable compounds that are flexible in the cured state and exhibit particularly good adhesion, especially to plastics. Furthermore, the cured compounds should exhibit high peel strength and resistance to temperature and humidity. The invention also aims to provide particularly environmentally friendly curable compounds or adhesives through the use of bio-based raw materials.

[0017] This problem is solved according to the invention by a hardenable mass according to claim 1.

[0018] The actinic radiation-curable mass according to the invention comprises:

[0019] (A) a urethane(meth)acrylate based on hydroxy-functional polytrimethylene ether glycol (a1);

[0020] (B) a (meth)acrylate monomer; and

[0021] (C) a radical initiator component comprising a radical photoinitiator (c1), wherein component (A) is present in the curable mass in a proportion of at least 30 wt.%, based on the total weight of components (A) to (C).

[0022] Further advantageous variants are specified in the dependent claims, which can optionally be combined with one another.

[0023] The masses according to the invention are liquid, especially at room temperature, and can be hardened by exposure to actinic radiation.

[0024] Compared to formulations described in the prior art, the hardened masses exhibit high adhesion to plastics and high peel strength. The desired mechanical and adhesive properties are achieved in particular by the minimum proportion of 30 wt.% of component (A), based on the total weight of the reactive components (A) to (C).

[0025] A further advantage of the compositions according to the invention is the possible use of bio-based 1,3-propanediol as a starting material for the synthesis of the urethane(meth)acrylate component (A), which allows the curable composition to be formulated in a particularly environmentally friendly manner. The invention further relates to a method for joining, potting, sealing, and / or coating using the curable composition as described above, which comprises the following steps:

[0026] (a) Providing a first substrate;

[0027] (b) Dosing the curable mass onto the first substrate;

[0028] (c) Optionally adding a second substrate to form a substrate composite; and

[0029] (d) Hardening of the mass on the substrate or in the substrate composite by actinic radiation.

[0030] The use of the hardenable compound enables particularly reliable joining, potting, sealing and / or coating of substrates using sustainable raw materials.

[0031] DETAILED DESCRIPTION OF PREFERRED EXECUTION FORMS

[0032] The invention is described in detail below, using examples of preferred embodiments, which, however, should not be understood in a limiting sense. The following definitions are used in the description:

[0033] “Single-component” or “single-component mass” means, within the meaning of the invention, that the aforementioned components of the mass are present together in a single packaging unit.

[0034] The masses are considered "processable" if the viscosity of the respective finished mixed mass changes by less than 25% during storage at room temperature over the specified period.

[0035] For the purposes of the invention, “liquid” means that at 23 ± 2 °C the loss modulus G” determined by viscosity measurement is greater than the storage modulus G' of the mass in question.

[0036] "At least difunctional" means that each molecule contains two or more units of the respective functional group. Where the indefinite article "ein" or "eine" is used, this also includes the plural form "ein oder mehr" (one or more), unless explicitly excluded.

[0037] All weight percentages listed below refer to the total weight of the reactive components (A) to (C), unless otherwise stated.

[0038] According to the invention, the curable mass used comprises a urethane (meth)acrylate (A) based on hydroxy-functional polytrimethylene ether glycol (a1), a (meth)acrylate monomer (B) and a photoinitiator component (C) comprising a radical photoinitiator (c1).

[0039] The individual components of the actinic radiation-curable mass according to the invention are described in more detail below. However, the respective components can be combined with one another in any desired manner.

[0040] Component (A): Urethane methacrylate

[0041] The urethane(meth)acrylate (A) is based on polytrimethylene ether glycol (poly(1,3-propanediol), PO3G) and offers technical advantages over urethane(meth)acrylates based on alternative polyol backbones. These include high elongation at break and peel strength of the cured mass, as well as high temperature and humidity resistance.

[0042] Component (A) is not further structurally restricted as long as it comprises a urethane (meth)acrylate based on hydroxy-functional polytrimethylene ether glycol. In particular, the polymer backbone of the urethane (meth)acrylate is formed from repeating units of the hydroxy-functional polytrimethylene ether glycol.

[0043] The urethane(meth)acrylate (A) can have an average molar mass of 500 to 20,000 g / mol, preferably of 750 to 15,000 g / mol, particularly preferably of 1,000 to 10,000 g / mol.

[0044] In one variant, the urethane(meth)acrylate (A) is obtained, in particular by reacting the hydroxy-functional polytrimethylene ether glycol (a1) with at least a di-functional isocyanate (a2) to obtain an isocyanate-functional intermediate and subsequently reacting the isocyanate-functional intermediate with an isocyanate-reactive (meth)acrylate (a3).

[0045] In this way, an isocyanate-functional intermediate is initially obtained, which is accordingly an isocyanate-functional polytrimethylene glycol. The isocyanate-functional intermediate is then functionalized by reacting it with the isocyanate-reactive, in particular hydroxy-functional, (meth)acrylate (a3) ​​in order to equip the urethane (meth)acrylate (A) with the (meth)acrylate functionalities intended for radiation curing. The two-step reaction procedure allows for a particularly flexible selection of the components used.

[0046] The at least difunctional isocyanate (a2) and the hydroxyfunctional polytrimethylene ether glycol (a1) can be reacted in a ratio in the range of 0.5 : 1 ,0 to 3.0 : 1 ,0 based on the reactive isocyanate and hydroxyl groups (NCO : OH) of the respective compound, preferably from 1.5 : 1 ,0 to 2.5 : 1 ,0, particularly preferably from 1.9 : 1 ,0 to 2.1 : 1 ,0.

[0047] The isocyanate-reactive (meth)acrylate (a3) ​​can be a hydroxy-functional (meth)acrylate (a3) ​​and the obtained isocyanate-functional intermediate and the hydroxy-functional (meth)acrylate (a3) ​​can be reacted in a ratio of 1.0 : 0.1 to 1.0 : 1.5, based on the reactive isocyanate and hydroxyl groups (NCO : OH) of the respective compound, preferably from 1.0 : 0.25 to 1.0 : 1.2, particularly preferably from 1.0 : 0.75 to 1.0 : 1.1.

[0048] Optionally, one or more catalysts (a4) can be used to accelerate these reactions.

[0049] In another variant, urethane(meth)acrylate (A) is obtained, in particular, by reacting the hydroxy-functional polytrimethylene ether glycol (a1) with an isocyanate-functional (meth)acrylate (a5). This reaction allows urethane(meth)acrylate (A) to be obtained via a one-step synthesis, thus reducing the synthesis effort.

[0050] The isocyanate-functional (meth)acrylate (a5) and the hydroxy-functional polytrimethylene ether glycol (a1) can be reacted in a ratio in the range of 0.25 : 1 .0 to 1 .5 : 1 .0, based on the reactive isocyanate and hydroxyl groups (NCO : OH) of the respective compound, preferably from 0.5 : 1 .0 and 1 .1 : 1 .0, particularly preferably from 0.75 : 1 .0 to 1 .0 : 1 .0.

[0051] In both variants, the reaction behavior of component (A) within the curable mass and thus the achievable mechanical and adhesion properties of the cured mass can be adjusted by the ratio or ratios of the functional groups used in the production of the urethane(meth)acrylate (A), and can therefore be tailored to the intended application.

[0052] Furthermore, the reaction according to the variants described above can be carried out in the presence of an isocyanate-reactive capper (a6), wherein the isocyanate-reactive capper (a6) has at least one isocyanate-reactive group and is free of other groups capable of polymerization.

[0053] In this context, the term “free from further polymerization-capable groups” means that the isocyanate-reactive capper (a6) does not have any further reactive groups that can react and / or crosslink during the hardening of the mass.

[0054] By using the isocyanate-reactive capper (a6) during the synthesis of urethane(meth)acrylate (A), free isocyanate groups of the reactants can be reacted with the capper (a6) to obtain a urethane(meth)acrylate (A) with a desired functionality, based on the number of (meth)acrylate groups. In this way, the curing behavior of the compound can be easily controlled.

[0055] For example, the isocyanate-functional intermediate obtained from the reaction of the hydroxy-functional polytrimethylene ether glycol (a1) with the at least difunctional isocyanate (a2) can be reacted with a mixture of hydroxy-functional (meth)acrylate (a3) ​​and the capper (a6), optionally in the presence of the catalyst (a4).

[0056] The urethane(meth)acrylate (A) can exhibit an average functionality of up to 2.0, based on the number of (meth)acrylate groups. The average functionality of the urethane(meth)acrylate (A) can be adjusted depending on the mixing ratios selected as described above. By using the capper (a6) and / or by using one or more of the components (a2), (a3) ​​or (a5) in a reduced quantity, urethane(meth)acrylates (A) with a functionality of less than 2.0 can also be obtained.

[0057] Furthermore, selected (meth)acrylate monomers (B) can be used as reactive diluents in the synthesis of component (A) if required. The selection and quantity of the reactive diluent to be used are known to those skilled in the art. The proportion of (meth)acrylate monomer (B) determined by its use as a reactive diluent is allocated to component (B) in proportion to the content of components (A) to (C).

[0058] Preferably the average functionality of the urethane(meth)acrylate (A) is in the range of 0.5 to 2.0, more preferably from 1.0 to 2.0, in each case based on the number of (meth)acrylate groups.

[0059] The term "average functionality" here refers to the average number of functional groups per molecule of urethane(meth)acrylate (A), relative to the number of (meth)acrylate groups. For example, a urethane(meth)acrylate (A) with an average functionality of 1 consists of a statistical mixture of reaction products, including both subfunctional urethane(meth)acrylates down to a functionality of 0, and urethane(meth)acrylates with functionalities greater than 1, for example, up to a functionality of 2.

[0060] (a1) Hydroxy-functional polytrimethylene ether glycol

[0061] Modern manufacturing methods enable the production of polytrimethylene ether glycol from biomass. In a first step, 1,3-propanediol is obtained, which is then converted to the hydroxy-functional polytrimethylene ether glycol (a1), for example, by polycondensation using a suitable catalyst. Exemplary syntheses can be found in WO 2023 / 022392 A 1 and WO 2023 / 022393 A1.

[0062] The hydroxy-functional polytrimethylene ether glycol (a1) can have a molecular weight of 250 to 20,000 g / mol, preferably 500 to 15,000 g / mol, and particularly preferably 750 to 10,000 g / mol. Commercially available products suitable as hydroxy-functional polytrimethylene ether glycols include Velvetol H250, Velvetol H500, Velvetol H1000, Velvetol H2000, and Velvetol H2700 from Wheylchem / Allessa (Germany), as well as Ecotrion H1000 and Ecotrion H2000 from Gantrade Corporation.

[0063] (a2) At least difunctional isocyanate

[0064] The at least difunctional isocyanate (a2) can be aliphatic, cycloaliphatic and / or aromatic.

[0065] Examples of at least difunctional isocyanates (a2) include hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-diisocyanatodicyclohexylmethane, methylenediphenyl isocyanate, 2,4,4-trimethylhexane-1,6-diisocyanate,

[0066] 2,2,4-Trimethylhexane-1,6-diisocyanate, toluene-2,4-diisocyanate and toluene-2,6-diisocyanate, which are commercially available under the trade name Desmodur from Covestro AG or under the trade name Vestanat from Evonik Operations GmbH.

[0067] Other suitable at least difunctional isocyanates (a2) are meta-tetramethylxylylene diisocyanate from Allnex Germany GmbH and meta-xylylene diisocyanate and 1,3-bis(isocyanatomethyl)cyclohexane, which are commercially available under the trade name Takenate from Mitsui Chemicals Inc.

[0068] Other suitable at least difunctional isocyanates (a2) are 4,4'-diisocyanato-3,3'-dimethylbiphenyl, available from Nisso Chemical Europe GmbH, as well as 1,5-naphthylene diisocyanate, 1,3-phenylene diisocyanate and

[0069] 1,4-Phenylene diisocyanate, which is available through TCI Chemicals.

[0070] Mixtures containing several of the aforementioned at least difunctional diisocyanates (a2) are also included.

[0071] (a3) Hydroxyfunctional (meth)acrylate

[0072] Examples of hydroxy-functional (meth)acrylates (a3) ​​are 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, glycerol di(meth)acrylate, glycerol mono(meth)acrylate, T rimethylolpropane di(meth)acrylate, pentaerythritol tri-(meth)acrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, polyalkylene glycol mono(meth)acrylate, polycaprolactone(meth)acrylate and dipentaerythritol penta(meth)acrylate.

[0073] Mixtures of several of the aforementioned raw materials are also included.

[0074] These raw materials are commercially available from Evonik Operations GmbH, Arkema Sartomer and GEO Speciality Chemicals.

[0075] (a4) catalyst

[0076] Optionally, one or more catalysts (a4) can be used to accelerate the reaction of the hydroxy-functional polytrimethylene ether glycol (a1) with the at least difunctional isocyanate (a2) and / or the subsequent reaction of the isocyanate-functional intermediate with the hydroxy-functional (meth)acrylate (a3) ​​and / or the capper (a6), as well as to accelerate the reaction of the at least difunctional isocyanate (a2) with the hydroxy-functional (meth)acrylate (a3).

[0077] One or more catalysts (a4) can also be used to accelerate the direct reaction of the hydroxy-functional polytrimethylene ether glycol (a1) with the isocyanate-functional (meth)acrylate (a5).

[0078] Suitable catalysts (a4) include organometallic compounds of tin, zinc, iron, titanium or bismuth, such as dibutyl or dioctyltin diacetate, dibutyl or dioctyltin dilaurate, and tributyltin acetate.

[0079] Other suitable catalysts (a4) are carboxylic acid salts of the above-mentioned elements, such as tin(II) acetate, tin(II) 2-ethylhexanoate, zinc(II) 2-ethylhexanoate and bismuth(III) neodecanoate.

[0080] Other suitable catalysts (a4) are amine compounds such as 1,4-diazabicyclo[2,2,2]octane (DABCO), diazabicycloundecene (DBU), triethylamine, and other tertiary amines. (a5) Isocyanate-functional (meth)acrylate

[0081] Suitable isocyanate-functional (meth)acrylates (a5) are, for example, reaction products such as those that can be obtained according to a process from DE 3 025 227 A1 by reacting aliphatic, cycloaliphatic and / or aromatic, at least difunctional isocyanates (a2) with hydroxy-functional (meth)acrylates (a3).

[0082] The at least difunctional isocyanate (a2) can be used stoichiometrically or in excess, for example in a molar ratio of 1.2 : 1.0, based on the hydroxyfunctional (meth)acrylate (a3), to obtain the isocyanate-functional (meth)acrylate (a5).

[0083] Preferably, the at least difunctional isocyanate (a2) is used stoichiometrically to the hydroxyfunctional (meth)acrylate (a3) ​​to avoid residues of unreacted difunctional isocyanate (a2).

[0084] Excess unreacted monomeric at least difunctional isocyanates (a2) can be separated from the reaction mixture by distillation, for example by vacuum distillation using a thin-film, thin-layer, or short-path evaporator. Such distillation methods are described in the Plastics Handbook Volume 7, “Polyurethanes” (GW Becker (Editor), Hanser-Verlag, Munich, 3rd edition 1993, page 425).

[0085] Examples of suitable isocyanate-functional (meth)acrylates (a5) are 2-isocyanatoethyl methacrylate (removal MOI), 2-isocyanatoethyl acrylate (removal AOI or removal AOI-VM), 1,1-bis(acryloyloxymethyl)ethyl isocyanate (removal BEI), 2-(2-isocyanatoethoxy)ethyl methacrylate (removal MOI-EG), available from Resonac Corporation, and 2-hydroxyethyl propenoate adduct with 5-isocyanato-1-(isocyanatomethyl)-1,3,3-trimethylcyclohexane (VESTANAT EP-DC 1241), available from Evonik Operations GmbH.

[0086] (a6) Capper

[0087] During the synthesis of urethane(meth)acrylate (A), a capper (a6) can optionally be used to react free isocyanate groups. The use of the capper (a6) can advantageously influence the functionality of the urethane(meth)acrylate (A) and furthermore prevent the presence of free, unreacted isocyanate groups in the curable mass.

[0088] The structure of the capper (a6) is not further restricted as long as it has at least one isocyanate-reactive group and no additional group capable of polymerization, i.e., no reactive groups that can react and / or crosslink during the hardening of the mass according to the invention.

[0089] The capper (a6) can be di- or higher-functional and can optionally be used to crosslink two or more urethane(meth)acrylates (A). Preferably, however, the capper (a6) is monofunctional.

[0090] In addition to at least one isocyanate-reactive group, the capper (a6) preferably possesses an aromatic residue or an alkyl or aralkyl residue. The alkyl residue can be linear or branched.

[0091] A capper (a6) with an aliphatic alkyl group having 2 to 20 carbon atoms is particularly preferred.

[0092] The capper (a6) can, for example, be selected from the group consisting of thiols, amines, alcohols, and mixtures thereof. Preferably, it is a hydroxy-functional capper (a6).

[0093] Furthermore, the capper (a6) can contain heteroatoms such as nitrogen, sulfur, phosphorus and / or oxygen.

[0094] Preferably, the capper (a6) is an aliphatic primary or secondary alcohol or a hydroxy-functional alkyl ether.

[0095] Examples of monohydric alcohols that can be used as cappers (a6) are ethanol, n-propanol, n-butanol, n-amyl alcohol, n-hexanol, n-heptanol, n-octanol, n-nonanol, n-decanol, n-undecanol, n-dodecanol, 2-ethylhexanol, 2-butyl-1-octanol and 3,7-dimethyl-1-octanol, as well as other aliphatic, optionally branched, alcohols.

[0096] Hydroxyfunctional monoalkyl ethers can be prepared, for example, starting from ethylene glycol, propylene glycol, or tetramethylene glycol. Examples of hydroxyfunctional monoalkyl ethers that can be used as cappers (a6) are diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether.

[0097] Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether,

[0098] Ethylene glycol monobutyl ether, ethylene glycol monolauryl ether,

[0099] Propylene glycol monomethyl ether, propylene glycol monoethyl ether,

[0100] Propylene glycol monobutyl ether, dipropylene glycol monoethyl ether,

[0101] Dipropylene glycol monobutyl ether and 2-ethylhexyloxyethanol.

[0102] The use of isocyanate-functional cappers (a6) suitable for reaction with the hydroxy-functional polytrimethylene ether glycol (a1) is also in accordance with the invention.

[0103] Optionally, one or more catalysts (a4) can be used to accelerate the reaction of the capper (a6).

[0104] During the synthesis of urethane(meth)acrylate (A), suitable stabilizers (a7) such as phenolic antioxidants or other radical scavengers and / or stabilizers known to those skilled in the art can optionally be added. Examples of such stabilizers (a7) are butylhydroxytoluene (BHT) and hydroquinone monomethyl ether (HQMME).

[0105] Component (A) is present in the curable mass according to the invention, based on the total weight of the reactive components (A) to (C), in a proportion of at least 30 wt.%.

[0106] For example, component (A) is present in a proportion of 30 to 85 wt.%, preferably in a proportion of 35 to 60 wt.%, in each case based on the total weight of the reactive components (A) to (C).

[0107] Component (B): (Meth)acrylate monomer

[0108] The term "(meth)acrylates" is used here and in the following to refer to derivatives of acrylic acid and methacrylic acid, as well as combinations and mixtures thereof. (Meth)acrylamide and compounds derived from it are also included under the term "(meth)acrylate".

[0109] The (meth)acrylate monomer (B) is not further structurally restricted.

[0110] The only crucial factor for the desired reaction behavior of the curable mass and the property profile after curing is that component (B) is a monomer of the respective (meth)acrylate and not a poly(meth)acrylate.

[0111] The (meth)acrylate monomer (B) can exist in a mono- or higher-functional form.

[0112] Both aromatic and aliphatic monomers, including linear or branched (meth)acrylate monomers (B), can be used.

[0113] Geeignet sind beispielsweise die folgenden (Meth)acrylatmonomere (B): lsobornyl(meth)acrylat, Stearyl(meth)acrylat, Tetrahydrofurfuryl(meth)acrylat, Cyclohexyl(meth)acrylat, 3,3,5-Trimethylcyclohexanol(meth)acrylat,

[0114] Behenyl(meth)acrylat, 2-Methoxyethyl(meth)acrylat und andere ein- oder mehrfach alkoxylierte (Meth)alkylacrylate, lsobutyl(meth)acrylat, lsooctyl(meth)acrylat, Lauryl(meth)acrylat, T ridecyl(meth)acrylat, lsostearyl(meth)acrylat, 2-(o-Phenylphenoxy)ethyl(meth)acrylat,

[0115] (Meth)acryloylmorpholin, 4-Butandioldi(meth)acrylat,

[0116] 1 ,6-Hexandioldi(meth)acrylat, 1 , 10-Decandioldi(meth)acrylat,

[0117] Tricyclodecandimethanoldi(meth)acrylat, Dipropylenglycoldi(meth)acrylat, T ripropylenglycoldi(meth)acrylat, Polybutadiendi(meth)acrylat,

[0118] Cyclohexanediethanol di(meth)acrylate, diurethane(meth)acrylates of monomeric, oligomeric or polymeric diols and polyols, trimethylolpropane tri(meth)acrylate (TMPT(M)A), and

[0119] Dipentaerythritol hexa(meth)acrylate (DPH(M)A), and combinations thereof.

[0120] Higher-functional (meth)acrylate monomers (B) derived from multiply branched or dendrimeric alcohols can also be used advantageously.

[0121] Furthermore, (meth)acrylic acid amides are suitable as component (B), including, for example: (meth)acrylamide, N-methyl(meth)acrylamide,

[0122] N,N-dimethyl(meth)acrylamide, N-ethyl(meth)acrylamide,

[0123] N,N-diethyl(meth)acrylamide, N-isopropyl(meth)acrylamide,

[0124] N-butyl(meth)acrylamide, Nt-butyl(meth)acrylamide, N,N-dibutyl(meth)acrylamide, N-phenyl(meth)acrylamide, N-(meth)acryloylmorpholine, N-(meth)acryloylpiperidine, N-(meth)acryloylpiperidine, N-(1,1-dimethyl-3-oxobutyl)(meth)acrylamide, N-1,1,3,3-tetramethylbutyl(meth)acrylamide, dimethylene bis(meth)acrylamide, tetramethylene bis(meth)acrylamide, trimethylhexamethylene bis(meth)acrylamide and tri(meth)acryloyldiethylenetriamine.

[0125] A combination of several (meth)acrylate monomers (B) is also in accordance with the invention.

[0126] The proportion of the (meth)acrylate monomer (B) in the curable mass according to the invention can be from 10 to 68 wt.%, preferably from 40 to 65 wt.%, in each case based on the total weight of the reactive components (A) to (C).

[0127] Component (C): Radical initiator component

[0128] The radical initiator component (C) comprises at least one radical photoinitiator (c1) and enables the hardening of the mass according to the invention by actinic radiation.

[0129] The curable mass according to the invention can contain from 0.05 to 15 wt.% of the radical initiator component (C), preferably from 0.5 to 8 wt.%, in each case based on the total weight of the reactive components (A) to (C).

[0130] (c1) Radical photoinitiator

[0131] All common, commercially available compounds can be used as radical photoinitiators (c1), such as α-hydroxyketones, benzophenone, α,α'-diethoxyacetophenone,

[0132] 4,4-Diethylaminobenzophenone, 2,2-Dimethoxy-2-phenylacetophenone,

[0133] 4-isopropylphenyl-2-hydroxy-2-propyl ketone, 1-hydroxycyclohexylphenyl ketone, isoamyl para-dimethylaminobenzoate, methyl 4-dimethylaminobenzoate, methyl ortho-benzoyl benzoate, benzoin, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2-Hydroxy-2-methyl-1-phenyl-propan-1-one,

[0134] 2-isopropylthioxanthone, dibenzosuberone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoylethoxylphenylphosphine oxide and bisacylphosphine oxides, wherein the aforementioned compounds can be used alone or in combination of two or more of the aforementioned compounds as a radical photoinitiator (c1).

[0135] Omnirad can act as a radical photoinitiator (c1) that can be activated by UV radiation. TM-Types from IGM Resins are used, for example the types Omnirad 184, Omnirad 500, Omnirad 1173, Omnirad 2959, Omnirad 754, Omnirad BDK, Omnirad 369, Omnirad 907, Omnirad 2022, Omnirad 2100, Omnirad 784, Omnirad 250, Omnirad TPO, Omnirad TPO-L, Omnirad 819, Omnirad 819 DW, Omnirad MBF, Omnirad BMS, Omnirad 4265.

[0136] The preceding lists are to be seen as exemplary for the radical photoinitiator (c1) and are by no means to be understood as limiting.

[0137] The radical photoinitiator used as component (c1) in the masses according to the invention is preferably activatable by actinic radiation of a wavelength in the range of 200 to 400 nm, particularly preferably from 250 to 365 nm.

[0138] If required, the radical photoinitiator (c1) can be combined with a suitable sensitizing agent, which is added as an additive (D).

[0139] The radical photoinitiator (c1) is present in the curable mass in a proportion of 0.05 to 5 wt.%, preferably 0.5 to 3 wt.%, in each case based on the total weight of the reactive components (A) to (C).

[0140] In one variant, the component (C) consists of the radical photoinitiator (c1).

[0141] (c2) Radical initiator for heat curing

[0142] Furthermore, it is possible to cure the curable mass according to the invention not only with light but also with heat. For this purpose, a radical initiator for heat curing (c2) can be added in addition to the radical photoinitiator (c1).

[0143] The radical initiator for heat curing (c2) can, for example, be selected from the peroxo compounds and / or the benzpinacols.

[0144] Suitable peroxo compounds include, for example, peroxo(di)esters, hydroperoxides, (di)alkyl peroxides, ketone peroxides, perketals, peracids, and peroxomonocarbonates. Furthermore, peroxodicarbonates, such as those described in WO 2023 / 030 763 A1, can be advantageously used in the curable mass according to the invention. Examples of suitable peroxoesters include cumene peroxyneodecanoate, 1,1,3,3-tetramethylbutylperoxyneodecanoate, tert-amylperoxyneodecanoate, tert-butylperoxyneodecanoate, 1,1,3,3-tetramethylbutylperoxypivalate, tert-amylperoxypivalate, tert-Butyl peroxypivalate, didecanoyl peroxide, dilauroyl peroxide, 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)-hexane, 1,1,3,3-tetramethylbutyl-peroxy-2-ethylhexanoate, tert-amyl peroxy-2-ethylhexanoate, dibenzoyl peroxide, tert- Butyl peroxy-2-ethylhexanoate, tert-butylperoxyisobutyrate, tert-butylperoxy-3,5,5- trimethylhexanoate, tert-butyl peroxyacetate and tert-butyl peroxybenzoate.

[0145] Examples of suitable hydroperoxides include diisopropylbenzene mono-hydroperoxide, p-menthane hydroperoxide, cumene hydroperoxide, 1, 1, 3, 3-

[0146] Tetramethylbutyl hydroperoxide, tert-butyl hydroperoxide and tert-amyl hydroperoxide.

[0147] Examples of suitable peroxomonocarbonates include tert-amyl-peroxy-2-ethylhexyl carbonate, tert-butyl-peroxyisopropyl carbonate and tert-butyl-peroxy-2-ethylhexyl carbonate.

[0148] Examples of suitable peroxodicarbonates include di-(4-tert-butyl-cyclohexyl)-peroxodicarbonate, di-(2-ethylhexyl)-peroxodicarbonate, di-n-butyl-peroxodicarbonate, dicetyl peroxodicarbonate and dimyristil peroxodicarbonate.

[0149] Benzpinacol and derivatives thereof, as described, for example, in US 4,288,527 A, can also be used as radical initiators for hot curing (c2). These include, in particular, halogenated, alkylated, and methoxy-substituted benzpinacols.

[0150] Furthermore, protected benzopinacols can be used as component (c2). These can be either singly or doubly protected and include silyl-protected, in particular singly and doubly trialkylsilyl-protected, benzopinacols.

[0151] Examples of benzopinacols that can be used in the curable masses according to the invention are 1,1,2,2-tetraphenyl-1,2-ethanediol, 1,1,2,2-tetrakis(4-methylphenyl)-1,2-ethanediol, 1,1,2,2-tetrakis(4-methoxyphenyl)-1,2-ethanediol, 1,1,2,2-tetrakis(4-chlorophenyl)-1,2-ethanediol, 1-hydroxy-2-trimethylsiloxy-1,1,2,2-tetraphenylethane, 1,1,2,2-tetraphenyl-1,2-bis-

[0152] (trimethylsiloxy)ethane and 1,1,2,2-tetrakis(4-methylphenyl)-1,2-bis-

[0153] (trimethylsiloxy)ethane. The radical initiator for hot curing (c2) can be present in the masses according to the invention in a proportion of 0 to 10 wt.%, preferably from 0.1 to 5 wt.%, in each case based on the total weight of the reactive components (A) to (C).

[0154] Component (D): Additives

[0155] In addition to components (A) to (C), the hardenable mass according to the invention may contain one or more further additives (D).

[0156] Catalysts are one example, but not an exhaustive one.

[0157] Toughness modifiers such as core-shell particles or block copolymers,

[0158] Dyes, pigments, fluorescent agents, sensitizing agents,

[0159] Thixotropic agents, thickeners, thermostabilizers, antioxidants, UV-

[0160] Stabilisers, plasticisers, fillers, flame retardants, thermally and / or electrically conductive particles, corrosion inhibitors, water scavengers, non-reactive diluents, leveling and wetting additives, adhesion promoters and combinations thereof that can be used as additives (D).

[0161] The additives are preferably present in the hardenable mass in a proportion of 0 to 80 wt.%, particularly preferably in a proportion of 1 to 50 wt.%, in each case based on the total weight of the mass.

[0162] Formulation of the hardenable mass

[0163] A formulation of the curable mass according to the invention for use in the process according to the invention comprises at least the components (A) to (C) described above.

[0164] According to one variant, the curable mass comprises the following components, each based on the total weight of the reactive components (A) to (C):

[0165] (A) 30 to 85 wt.% of urethane(meth)acrylate;

[0166] (B) 10 to 68 wt.% of the (meth)acrylate monomer; and

[0167] (C) 0.05 to 15 wt.% of the radical initiator component comprising a radical photoinitiator (c1), wherein the proportions of components (A) to (C) add up to 100 wt.%.

[0168] In addition to the radical photoinitiator (c1), the radical initiator component (C) can include the radical initiator for heat curing (c2).

[0169] Components (A) to (C) can be present in a proportion of 20 to 100 wt.% in the curable mass, preferably 50 to 99 wt.%, in each case based on the total weight of the mass.

[0170] Optionally, the hardenable mass according to the invention can contain 0 to 80 wt.% of additives as component (D), based on the total weight of the mass.

[0171] The hardenable mass according to the invention can consist of components (A) to (C) and optionally component (D).

[0172] The curable mass according to the invention is preferably provided as a single-component mass.

[0173] Properties and uses of the hardenable compound

[0174] The previously described hardenable mass allows for a wide range of properties to be achieved.

[0175] The hardenable mass is stable during storage and has a processing time of at least 3 days at room temperature.

[0176] The hardenable mass according to the invention can be hardened with actinic radiation and optionally additionally with heat.

[0177] The hardened compound is characterized by high elongation at break. The cured compound is particularly flexible and therefore especially suitable for applications subject to recurring mechanical stresses. Thus, the compound according to the invention can be used in particular for joining, potting, sealing, and / or coating electrical and / or optical components that are exposed to thermal and / or mechanical alternating stresses. Examples include the bonding of loudspeaker components, such as coils and / or diaphragms, or the fixing of lenses and / or mirrors in automotive LiDAR modules that must withstand the shock loads during driving.

[0178] To meet the requirements in such applications, an elongation at break of at least 50% is typically required, so the cured mass should ideally have an elongation at break of at least 50%. Preferably, the cured mass has an elongation at break of at least 100%, and particularly preferably an elongation at break of 150% or more. The elongation at break can be determined according to DIN EN ISO 527.

[0179] The cured compound exhibits a tensile strength of at least 5 MPa, for example 8 MPa or higher, preferably 10 MPa or higher, to create a particularly strong bond or coating. The tensile strength can be determined according to DIN EN ISO 527.

[0180] The hardened compound is also particularly resistant to peel stress, such as that encountered during the bonding of flat ribbon cables. The peel resistance for the substrate combination polycarbonate / polycarbonate (PC / PC) is, for example, at least 10 N / cm, preferably 15 N / cm or more, and particularly preferably 20 N / cm or more.

[0181] On the PC / PC substrate combination, the hardened mass achieves compressive shear strengths of at least 5 MPa.

[0182] Another property of the hardened material is its high resistance to temperature stress. After 7 days at 150 °C, at least 25% of the initial elongation at break remains. The tensile strength also decreases, in particular to a maximum of 25% of the initial value.

[0183] Measurement methods and definitions used

[0184] room temperature

[0185] Room temperature is defined as 23 °C ± 2 °C. Curing

[0186] "Curing" is defined as a polymerization or addition reaction beyond the gel point. The gel point is the point at which the storage modulus G' equals the loss modulus G".

[0187] memory module

[0188] The dynamic-mechanical properties of the cured materials were determined by Dynamic Mechanical Thermal Analysis (DMTA) in accordance with ISO 6721. The specimens, measuring 40 x 5 x 0.5 mm, were cured for 1 minute at 200 mW / cm². 2in a suitable plastic mold. The glass transition temperature is defined as the value at which the magnitude of the first derivative of the storage modulus (E') reaches its maximum (inflection point, see ISO 6721-11:2012 Section 3.1). The storage modulus for the respective temperatures was determined according to ISO 6721-4:2008. The measurement was carried out in a temperature range of 0–300 °C with a heating rate of 1 K / min at a frequency of 1 Hz with an amplitude of 30 pm. A Netzsch DMA 242E was used as the measuring instrument.

[0189] Elongation at break and tensile strength

[0190] Shoulder bars of defined size (dimensions 25 x 5.5 x 2 mm, measuring section 10 x 2 x 2 mm) were cast from the mass. The shoulder bars were irradiated from both sides for 60 seconds each (DELOLUX 20 / 400; intensity: 200 mW / cm²). 2The test specimens were conditioned for 24 hours in the dark at room temperature prior to testing. The shoulder bars were then pulled apart in a Zwick tensile testing machine at a speed of 30 mm / min, and the tensile strength and elongation at break were determined according to DIN EN ISO 527.

[0191] Thermal resistance

[0192] To determine thermal resistance, shoulder bars were produced analogously to the measurements of elongation at break and tensile strength and stored in an oven at 150 °C for 7 days. After oven storage, the shoulder bars were conditioned for 24 hours at room temperature and then tested. Peel strength

[0193] Two polycarbonate (PC) sheets (dimensions 250 mm x 30 mm x 0.1 mm) were bonded together with a layer thickness of 0.1 mm. The bonded sheets were irradiated for 60 seconds (DELOLUX 20 / 400; intensity: 200 mW / cm²). 2The test was performed on a Zwick universal testing machine by pulling the films apart at an angle of 180° at a testing speed of 200 mm / min. For evaluation, the average peel force in Newtons per sample width was determined from the peeling diagram of at least 120 mm of peeling.

[0194] compressive shear strength (DSF) after exposure

[0195] Two PC / PC test specimens (dimensions 20 mm x 20 mm x 5 mm) were bonded with a 5 mm overlap using the respective adhesive. A bead of the adhesive was applied to the first specimen, and then a second specimen was joined. The adhesive layer thickness of 0.1 mm and the overlap were adjusted using spacers and an adhesive applicator. The bonded specimens were irradiated for 60 seconds (DELOLUX 20 / 400; intensity: 200 mW / cm²). 2The specimens were conditioned for 24 hours in the dark at room temperature prior to testing. Testing was performed at room temperature on a Zwick Roell "AIIIRoundLine" testing machine at a deformation rate of 10 mm / min. The result is the mean value of 5 samples.

[0196] Viscosity and processing time

[0197] To determine the processing time, the viscosity of the curable mass was measured at a shear rate of 10⁻⁶ / s using an Anton Paar MCR-302 rheometer. A PP20 plunger was used with a gap of 500 pm and a temperature of 23 ± 1 °C. Sufficient processing time is achieved if the measured viscosity decreases to less than 100% of the initial value after 24 hours of storage at room temperature.

[0198] GPC measurement

[0199] The average molar masses M nThe values ​​were determined using a Viscotek TDA 302 GPC (refractive index and viscosity detector) from Malvern Panalytical GmbH. The GPC columns used were Viscotek LT4000L (mixed bed) and Viscotek T1000 (single-pore) and were calibrated with polystyrene calibration standards from M. n Calibrated from 162 Da to 51,150 Da. Tetrahydrofuran was used as the mobile phase. The flow rate was 1 mL / min at a measurement temperature of 35 °C. For sample preparation, 40 mg of the sample was dissolved in 10 ml of THF. After a residence time of 15 min, the solution was filtered through a syringe filter (0.2 pm) and 100 pl of the solution was injected via an injection loop.

[0200] Production examples

[0201] To produce the curable compounds according to the invention, the urethane (meth)acrylate (A) was first placed in a speed mixer beaker. The corresponding (meth)acrylate monomers (B) were then added. Subsequently, under light-protected conditions, the radical initiator (c1) was added, as well as optionally the radical initiator (c2) and / or the additives (D). The mixture was then homogenized in a Hauschild speed mixer. Finally, the mixture was filled into a suitable container for further testing.

[0202] Raw materials used

[0203] Component (A) - Urethane (meth)acrylate: a1-1 : Velvetol H2700 (Wheylchem / Allessa, Germany) a1-2: Ecotrion H2000 (Gantrade Corporation, Belgium) a1-3: PolyTHF 2000 (BASF, Germany) a1-4: Lupranol 1000 / 1 (BASF, Germany) a1-5: Kuraray Polyol C-3090 (Kuraray Europe GmbH, Germany) a2-1 : Isophorone diisocyanate (IPDI, Evonik Operations GmbH, Germany) a3-1 : 4-Hydroxybutyl acrylate (4-HBA, Osaka Organic Chemical Ind. Ltd., Japan) a3-2 : 2-Hydroxyethyl acrylate (2-HEA, Osaka Organic Chemical Ind. Ltd.) a4-1 : Dibutyltin dilaurate (DBTL, (Sigma-Aldrich Chemie GmbH, Germany) a4-2: Bismuth hneodecanoate (Sigma-Aldrich Chemie GmbH a4-3: Tin(II) ethylhexanoate (Sigma-Aldrich Chemie GmbH a5-1 : Carenz AOI (Resonac Europe GmbH, Germany) a7-1 : Butylhydroxytoluene: BHT (Sigma-Aldrich Chemie GmbH, Germany) a7-2: Hydroquinone monomethyl ether: HQMME (Sigma-Aldrich Chemie GmbH, Germany)

[0204] Component (B) - (Meth)acrylate monomer:

[0205] B-1 : Dimethylacrylamide (DMAA, Rahn GmbH, Switzerland)

[0206] B-2: Isobornyl acrylate: I BOA (Kowa Europe, Germany)

[0207] B-3: Sartomer 420 (3,3,5-Trimethylcyclohexyl acrylate, Arkema, France)

[0208] B-4: ACMO (Rahn GmbH, Switzerland)

[0209] B-5: Acrylic acid (IMCD Deutschland GmbH, Germany)

[0210] B-6: GM EC (Glycerol carbonate methacrylate, Kowa Europe, Germany)

[0211] Component (C) - radical initiator component: c1-1 : Omnirad 819 (IGM Resins, Netherlands)

[0212] Component (D) - Additive:

[0213] D-1 : Dynasylan Glymo (Evonik Industries AG, Germany)

[0214] D-2: Tinuvin 123 (BTC Europe, Germany)

[0215] D-3: Tinuvin 384-2 (BTC Europe, Germany)

[0216] D-4: HDK H 2000 (IMCD Deutschland GmbH, Germany)

[0217] Synthesis examples

[0218] Example 1: Synthesis of urethane(meth)acrylate (A1-1):

[0219] In a suitable reaction vessel, 451 g of Velvetol H2700 (a1-1) were melted at 100 °C and dried under vacuum for 30 min. After cooling to 40 °C, 0.21 g of BHT (a7-1), 0.22 g of HQMME (a7-2) and

[0220] 71.8 g of isophorone diisocyanate (a2-1) was added and homogenized. After adding 0.21 g of DBTL (a4-1), the mixture was stirred at 60 °C until the isocyanate band remained constant. All measurements were performed using a Bruker IR spectrometer.

[0221] 46.6 g of 4-hydroxybutyl acrylate (a3-1) were added to the isocyanate-functional intermediate and stirred at the same temperature. The urethane (meth)acrylate (A1-1) with an average molar mass of 7,200 g / mol and an average functionality of 2, based on the number of (meth)acrylate groups, was obtained without further work-up.

[0222] Example 2: Synthesis of urethane methacrylate (A1-2):

[0223] In a suitable reaction vessel, 200 g of Ecotrion H2000 (a1-2) were melted at 100 °C and dried under vacuum for 30 min. After cooling to 40 °C, 0.11 g of BHT (a7-1), 0.12 g of HQMME (a7-2) and

[0224] 42.9 g of isophorone diisocyanate (a2-1) were added and homogenized. After adding 0.10 g of DBTL (a4-1), the mixture was stirred at 60 °C until the isocyanate band stabilized. 27.8 g of 4-hydroxybutyl acrylate (a3-1) were added to the isocyanate-functional intermediate, and stirring continued at the same temperature. The urethane (meth)acrylate (A1-2), with an average molar mass of 6,000 g / mol and an average functionality of 2 based on the number of (meth)acrylate groups, was obtained without further work-up.

[0225] Example 3: Synthesis of urethane(meth)acrylate (A1-3):

[0226] In a suitable reaction vessel, 900 g of Velvetol H2700 (a1-1) were melted at 100 °C and dried under vacuum for 30 min. After cooling to 40 °C, 0.43 g of BHT (a7-1), 0.44 g of HQMME (a7-2) and

[0227] 88.9 g of retained AOI (a5-1) was added and homogenized. After adding 0.47 g of bismuth neodecanoate (a4-2), the mixture was stirred at 60 °C until the isocyanate band completely disappeared. The urethane (meth)acrylate (A1-3) with an average molar mass of 4,500 g / mol and an average functionality of 2, based on the number of (meth)acrylate groups, was obtained without further work-up. Example 4: Synthesis of urethane methacrylate (A1-4):

[0228] In a suitable reaction vessel, 260 g of Velvetol H2700 (a1-1) were melted at 100 °C and dried under vacuum for 30 min. After cooling to 40 °C, 0.13 g of BHT (a7-1), 0.13 g of HQMME (a7-2), and 43.2 g of isophorone diisocyanate (a2-1) were added under dry air and homogenized. After adding 0.13 g of DBTL (a4-1), the mixture was stirred at 60 °C until the isocyanate band stabilized. 25.3 g of 4-hydroxyethyl methacrylate (a3-1) were added to the isocyanate-functional intermediate, and the mixture was stirred further at the same temperature. The urethane(meth)acrylate (A1-4) with an average molar mass of 7,300 g / mol and an average functionality of 2, based on the number of (meth)acrylate groups, was obtained without further processing.

[0229] Example 5: Synthesis of urethane methacrylate (A1-5):

[0230] The synthesis was carried out analogously to the example! However, instead of Velvetol H2700 (a1-1), 150 g of PolyTHF 2000 (a1-3) were used as the polyol, 17.4 g of 2-hydroxyethyl acrylate (a3-2), and 0.162 g of tin(II) ethylhexanoate (a4-3). The urethane(meth)acrylate (A1-5), with an average molar mass of 8,800 g / mol and an average functionality of 2 based on the number of (meth)acrylate groups, was obtained without further work-up.

[0231] Example 6: Synthesis of urethane methacrylate (A1-6):

[0232] In a suitable reaction vessel, 800 g of Lupranol 1000 / 1 (a1-4) was melted at 100 °C and dried under vacuum for 30 min. After cooling to 40 °C, 0.36 g of BHT (a7-1) and 108 g of isophorone diisocyanate (a2-1) were added under dry air and homogenized. After adding 0.36 g of DBTL (a4-1), the mixture was stirred at 60 °C until the isocyanate band stabilized. 17.6 g of 4-hydroxybutyl acrylate (a3-1) was added to the isocyanate-functional intermediate, and stirring continued at the same temperature. The urethane (meth)acrylate (A1-6), with an average molar mass of 15,200 g / mol and an average functionality of 2 based on the number of (meth)acrylate groups, was obtained without further work-up. Example 7: Synthesis of urethane(meth)acrylate (A1-7):

[0233] The synthesis was carried out analogously to Example 1. Instead of Velvetol H2700 (a1-1), 250 g of Lupranol 1000 / 1 (a1-4) were used as the polyol. The urethane(meth)acrylate (A1-7) with an average molar mass of 5,600 g / mol and an average functionality of 2, based on the number of (meth)acrylate groups, was obtained without further work-up.

[0234] Example 8: Synthesis of urethane methylacrylate (A1-8):

[0235] The synthesis was carried out analogously to Example 1. Instead of Velvetol H2700 (a1-1), 220 g of Kuraray polyol C-3090 (a1-5) were used as the polyol and 20% isobornyl acrylate as the reactive diluent. The urethane (meth)acrylate (A1-8), with an average molar mass of 7,200 g / mol and an average functionality of 2, based on the number of (meth)acrylate groups, was obtained without further work-up. The weight fraction of the reactive diluent isobornyl acrylate was included as the (meth)acrylate monomer in the example tables for component (B).

[0236] Table 1: Composition and properties of the hardenable masses according to the invention.

[0237] ^Value too low, not measurable

[0238] Table 2: Composition and properties of the hardenable masses and comparison masses according to the invention.

[0239] The compositions of Examples E1 to E12 according to the invention comprise the essential components. These are the urethane (meth)acrylate (A) based on polytrimethylene ether glycol, the (meth)acrylate monomer (B), and the radical initiator (C), which comprises a radical photoinitiator (c1). Optionally, further additives (D) are included.

[0240] Example E1 according to the invention uses a urethane (meth)acrylate (A) based on polytrimethylene ether glycol, which was obtained by reacting the hydroxy-functional polytrimethylene ether glycol (a1) with at least a difunctional isocyanate (a2) and subsequent functionalization with a hydroxy-functional (meth)acrylate (a3). The urethane (meth)acrylate A1-1 has an average molar mass of 7,200 g / mol and an average functionality of 2. The hardened mass exhibits good mechanical properties with respect to adhesion, elongation at break, and peel strength, and also shows good resistance to heat (150 °C, 7 days).

[0241] In example E2, a higher quantity of urethane(meth)acrylate A1-1 was used. The cured compound exhibits high elongation at break with slightly lower adhesion values, which nevertheless still meet the requirements and, in particular, decrease to no less than 25% of the initial value during storage at 150 °C for 7 days. The cured compound is therefore resistant to temperature stress.

[0242] In comparative examples V1 and V2, reduced proportions of the urethane(meth)acrylate A1-1 were used, which are outside the range according to the invention of at least 30 wt.%, based on the total weight of the reactive components (A) to (C).

[0243] Comparative example V1 with 20 wt% urethane(meth)acrylate A1-1 initially has an insufficient elongation at break of 1.3% and an unmeasurable peel strength due to insufficient strength.

[0244] The hardened reference compound V2 with 25 wt% urethane(meth)acrylate A1-1 initially exhibits good elongation at break, but this does not withstand thermal stress. Furthermore, the peel strength of the hardened compound is too low. The inventive example E3 with 30 wt% urethane(meth)acrylate A1-1 meets all mechanical requirements and shows sufficient resistance to temperature stress.

[0245] In Example E4, a urethane(meth)acrylate with a molar mass of 13,200 g / mol (A1-2) was used; in Example E5, a urethane(meth)acrylate obtained by direct functionalization of a hydroxy-functional polytrimethylene ether glycol (a1) with an isocyanate-functional (meth)acrylate (a5) was used. The hardened masses meet all mechanical requirements.

[0246] Example E6 shows an embodiment without the additive D-4. In this case too, a hardened mass is obtained that meets all mechanical requirements and is temperature-resistant.

[0247] Examples E7 to E10 show mixtures with different (meth)acrylate monomers (B). The hardened masses possess good adhesion properties and high elongation at break.

[0248] Example E11 shows the use of a methacrylate-functional urethane(meth)acrylate (A1-4). In Example E12, a methacrylate monomer (B-6) is used. The cured masses meet all requirements.

[0249] In comparative examples V3 to V6, urethane(meth)acrylates (A) were used which were not produced starting from polytrimethylene ether glycol.

[0250] The urethane (meth)acrylate in comparative example V3 is based on poly-THF, while comparative examples V4 and V5 are based on polypropylene glycol. None of the comparative examples V3 to V5 achieve the required peel strengths. The initial elongations at break are good, but they exhibit insufficient temperature resistance. These comparative examples demonstrate that the use of bio-based polytrimethylene ether glycol (a1) not only improves the environmental footprint of the composition according to the invention, but also results in improved mechanical and adhesion properties.

[0251] Comparative example V6 uses a urethane (meth)acrylate based on polycarbonate (A1-8). The cured compound exhibits high adhesion values ​​and good resistance to temperature stress. The elongation at break of the cured compound is too low due to the rigid polycarbonate backbone of component (A).

Claims

Patent claims 1. Actinically curable mass comprising the following components: (A) a urethane(meth)acrylate based on hydroxy-functional polytrimethylene ether glycol (a1); (B) a (meth)acrylate monomer; and (C) a radical initiator component comprising a radical photoinitiator (c1); wherein component (A) is present in the curable mass in a proportion of at least 30 wt.%, based on the total weight of components (A) to (C).

2. Curable mass according to claim 1, wherein the urethane(meth)acrylate (A) has an average functionality of up to 2.

0.

3. Curable mass according to claim 1 or 2, wherein the urethane(meth)acrylate (A) has an average molar mass of 500 to 20,000 g / mol.

4. Curable mass according to any of the preceding claims, wherein the urethane (meth)acrylate (A) is obtainable by reacting the hydroxy-functional polytrimethylene ether glycol (a1) with at least a di-functional isocyanate (a2) to obtain an isocyanate-functional intermediate and subsequently reacting the isocyanate-functional intermediate with an isocyanate-reactive (meth)acrylate (a3).

5. Curable mass according to claim 4, wherein the at least difunctional isocyanate (a2) and the hydroxyfunctional polytrimethylene ether glycol (a1) are reacted in a ratio in the range of 0.5:1 ,0 to 3.0:1 ,0, based on the reactive isocyanate and hydroxyl groups of the respective compound.

6. Curable mass according to claim 4 or 5, wherein the isocyanate-reactive (meth)acrylate (a3) ​​is a hydroxy-functional (meth)acrylate (a3), and wherein the isocyanate-functional intermediate and the hydroxy-functional (meth)acrylate (a3) ​​are in in a ratio ranging from 1.0:0.1 to 1.0:1.5, based on the reactive isocyanate and hydroxyl groups of the respective compound.

7. Curable mass according to any one of claims 1 to 3, wherein the urethane (meth)acrylate (A) is obtainable by reacting the hydroxy-functional polytrimethylene ether glycol (a1) with an isocyanate-functional (meth)acrylate (a5).

8. Curable mass according to claim 7, wherein the isocyanate-functional (meth)acrylate (a5) and the hydroxy-functional polytrimethylene ether glycol (a1) are reacted in a ratio in the range of 0.25:1 ,0 to 1 ,5:1 ,0, based on the reactive isocyanate and hydroxyl groups of the respective compound.

9. Curable mass according to any one of claims 4 to 8, wherein the reaction is carried out in the presence of an isocyanate-reactive capper (a6), wherein the isocyanate-reactive capper (a6) has at least one isocyanate-reactive group and is free of further groups capable of polymerization.

10. Curable mass according to any of the preceding claims, wherein the curable mass comprises the following components, each based on the total weight of the reactive components (A) to (C): (A) 30 to 85 wt.% of urethane(meth)acrylate; (B) 10 to 68 wt.% of the (meth)acrylate monomer; and (C) 0.05 to 15 wt.% of the radical initiator component comprising a radical photoinitiator (c1); wherein the proportions of components (A) to (C) add up to 100 wt.%.

11. Curable mass according to any of the preceding claims, wherein the curable mass contains as component (D) 0 to 80 wt.% of at least one additive, based on the total weight of the curable mass.

12. Curable mass according to any of the preceding claims, wherein the cured mass has a tensile strength of at least 5 MPa, determined according to DIN EN ISO 527.

13. Curable mass according to any of the preceding claims, wherein the cured mass has an elongation at break of at least 50%, determined according to DIN EN ISO 527.

14. Curable mass according to any one of the preceding claims, wherein the cured mass for the substrate combination polycarbonate / polycarbonate is exhibits a peel strength of at least 10 N / cm.

15. Method for joining, potting, sealing and / or coating using a curable compound according to any one of the preceding claims, wherein the method comprises the following steps: (a) providing a first substrate; (b) Dosing the curable mass onto the first substrate; (c) optionally adding a second substrate to form a substrate composite; and (d) Hardening of the mass on the substrate or in the substrate composite by actinic radiation.

Images