Transparent, fracture-resistant polymerization resins for the production of dental molded bodies

Description

[0001] The present invention relates to radically polymerizable compositions which are particularly suitable as dental materials for the production of dental moldings, such as artificial teeth, dentures, inlays, onlays, splints (bite splints), crowns, bridges, veneering materials and orthodontic appliances by generative processes.

[0002] Classical dental polymerization systems usually consist of a mixture of transparent liquid monomers, initiator components, stabilizers and pigments (J. Viohl, K. Dermann, D. Quast, S. Venz, The Chemistry of Dental Filling Resins, Carl Hanser Verlag, Munich-Vienna 1986, 21-27). Mixtures of dimethacrylates are usually used as monomers for the construction of polymer networks, e.g. in filling materials (cf. A. Peutzfeldt, Resin composites in dentistry: The monomer systems, Eur. J. Oral. Sci. 105 (1997) 97-116; N. Moszner, T. Hirt, New Polymer-Chemical Developments in Clinical Dental Polymer Materials: Enamel-Dentin Adhesives and Restorative Composites, J. Polym. Sci. Part A: Polym. Chem. 50 (2012) 4369-4402).Examples include the high-viscosity dimethacrylates 2,2-bis[4-(2-hydroxy-3-methacryloyloxypropyl)phenyl]propane (Bis-GMA) and 1,6-bis-[2-methacryloyloxyethoxycarbonylamino]-2,4,4-trimethylhexane (UDMA), as well as the low-viscosity dimethacrylates bismethacryloyloxymethyltricyclo[5.2.1.]decane (TCDMA), decanediol 1,10-dimethacrylate (D 3 MA), and triethylene glycol dimethacrylate (TEGDMA), which are used as diluent monomers. In contrast, the monofunctional monomer methyl methacrylate (MMA), which is low-viscosity but highly volatile, is primarily used for dentures.

[0003] Depending on the application, additional additives and initiators suitable for triggering radical polymerization are added. Photoinitiators for the visible spectrum are used to trigger polymerization with light. These photoinitiators form radicals with blue light and are characterized by good curing depth and excellent bleaching properties. Prosthetic materials contain powdered polymethyl methacrylate (PMMA) as a key component, which forms a paste with MMA. Curing occurs thermally or with redox initiators. In filling composites and luting cements, high proportions of inorganic fillers ensure high flexural strength and surface hardness, although fillers can have a detrimental effect on transparency.

[0004] A major problem of radical methacrylate polymers is the polymerization shrinkage (ΔV P ), ie the volume contraction of the methacrylate monomers used that occurs during polymerization, which can lead to, for example, very disadvantageous marginal gap formation in filling composites and adversely affects the dimensional stability of prosthetic materials (ΔV P is, for example, 21.0 vol.% for pure MMA).

[0005] Another disadvantage of PMMA or dimethacrylate polymers is their high brittleness. The low fracture toughness is an inherent property of amorphous PMMA glass and, in the case of polymer networks formed by dimethacrylate blends, is primarily caused by their highly irregular network structure.

[0006] In recent years, additive manufacturing processes for the production of dental molds have gained increasing interest and widespread use. In additive manufacturing processes, also known as generative manufacturing, 3D molds are created layer by layer from polymerizable materials based on a CAD dataset, with the layers curing achieved through controlled exposure. Stereolithography (SL) uses a UV laser as the light source. The DLP (Digital Light Processing) process uses a projectable image to cure the photopolymerization resin layer by layer.

[0007] Construction materials for the additive manufacturing of dental molds must meet various requirements with regard to the specific characteristics of this process. They should exhibit low viscosity and high transparency, as well as good mechanical properties after curing. The materials disclosed in the prior art are optimized with regard to certain properties, often at the expense of others.

[0008] The use of mono- and polyfunctional methacrylates as resins for generative processes is the subject of numerous patents and patent applications.

[0009] US 10,562,995 B2 discloses polymerization resins for the stereolithographic production of dental prostheses based on mixtures of aromatic di(meth)acrylates, which do not contain OH or COOH groups, with (meth)acrylic monomers, which contain at least one OH or COOH group.

[0010] US 10,568,814 B2 discloses photopolymerizable compositions for the production of artificial teeth and denture bases by 3D printing, which are said to exhibit high flexural strength and a high modulus of elasticity after curing. The materials are based on a mixture of ethoxylated bisphenol A dimethacrylate, monofunctional methacrylates, and urethane dimethacrylates.

[0011] EP 3 020 361 A1 relates to curable compositions for additive manufacturing processes containing radically polymerizable polysiloxanes and disiloxanes. The materials are said to be characterized by high dimensional stability and improved biocompatibility.

[0012] EP 3 494 954 A1 discloses photopolymerizable compositions for the production of dental prostheses containing a mixture of aromatic acrylates with a molecular weight of 200 to 800 g / mol and at least one other (meth)acrylate, which may contain aromatic and non-aromatic rings. The materials are said to be characterized by good Charpy fracture toughness.

[0013] EP 3 564 206 A1 discloses (meth)acryloxy-substituted benzoic acid esters which are said to be suitable as reactive diluents for additive manufacturing processes.

[0014] Dental molded articles must exhibit good fracture toughness, as well as good flexural strength and a high modulus of elasticity. Fracture toughness can be improved through internal plasticization, e.g., by adding flexible monomers. These have the disadvantage of significantly reducing the flexural strength and modulus of elasticity of the polymers. Therefore, according to the current state of the art, polymer particles with a core-shell structure are usually added to polymerization resins as so-called impact modifiers to improve fracture toughness. These particles result in relatively good flexural strength and a relatively high modulus of elasticity.

[0015] WO 2014 / 078537 A1 discloses resin mixtures for the production of dental moldings by 3D printing processes based on mono- and multifunctional methacrylates, which contain silicone-acrylate-based impact modifiers with a core-shell structure to improve impact and fracture toughness.

[0016] US 2018 / 0000570 A1 concerns construction materials based on mono- and multifunctional (meth)acrylates for the additive manufacturing of dental components. The construction materials contain silicone-acrylic-based rubber particles with a core-shell structure (product S2006, Mitsubishi Rayon Co.) as impact modifiers and oligomers produced by reacting trimethyl 1,6-diisocyanate, bisphenol A propoxylate, and 2-hydroxyethyl methacrylate (HEMA). The cured components are said to exhibit good mechanical and physical properties as well as good biocompatibility.

[0017] US 10,299,896 B2 and US 2019 / 0053883 A1 disclose dental components manufactured by additive manufacturing processes, which comprise at least two layers of differently composed construction materials. One layer is formed by a material containing oligomers obtained by reacting intermediates with terminal isocyanate groups with hydroxyl-based methacrylates, a polymerizable acrylic compound, and an impact modifier. At least one further layer is formed by a material containing a urethane monomer, a glycol dimethacrylate, and a filler. The combination of materials with different mechanical and physical properties is said to be advantageous for adapting the components to different requirements. Commercially available polymers with a core-shell structure are used as impact modifiers, such as the product M570 from Kaneka.

[0018] EP 3 564 282 A1 discloses curable compositions for high-temperature photopolymerization processes, which contain an oligomeric urethane dimethacrylate as a glass transition temperature modifier, a (poly)carbonate-(poly)urethane dimethacrylate as a toughness modifier, and optionally core-shell particles. They are said to have good thermomechanical properties and good biocompatibility and are suitable for the production of orthodontic appliances. EP 2 492 289 A1 discloses a polymerizable dental composition comprising an acrylic block copolymer (a) with at least one polymer block A, which mainly contains a (meth)acrylic acid ester unit, and at least one polymer block B, which mainly contains an acrylic acid ester unit.

[0019] The effectiveness of impact modifiers with a core-shell structure is based on the interaction of the tip of a developing crack with the core-shell polymer particles. These particles have a relatively soft polymer core and a hard polymer shell. When a crack tip encounters such a particle, voids form in the core and the polymer shell separates from the polymerized resin matrix, as well as the core from the shell, thus creating space (cavitation) for plastic deformation surfaces. A major disadvantage for dental applications is that core-shell polymers (CSP) significantly reduce the transparency of the materials, which has a detrimental effect on the stereolithographic construction process.

[0020] The invention is based on the object of providing materials for the production of dental molded articles that exhibit a property profile optimized for additive manufacturing processes. In particular, the materials should exhibit high transparency combined with good fracture toughness and high fracture energy. They should also exhibit low viscosity and good mechanical properties after water storage, as well as good biocompatibility.

[0021] According to the invention, this object is achieved by radically polymerizable dental materials as defined in the claims, which contain at least one ABA or AB block copolymer. The dental materials also contain at least one monofunctional, radically polymerizable monomer (a) and at least one radically polymerizable urethane di(meth)acrylate telechelate (b).

[0022] The dental materials according to the invention preferably have the following composition: (a) 30 to 70 wt.%, preferably 30 to 61 wt.% and particularly preferably 40 to 60 wt.% of at least one aromatic, bicyclic or tricyclic mono(meth)acrylate, (b) 20 to 60 wt.%, preferably 30 to 55 wt.% and particularly preferably 33 to 55 wt.% of at least one urethane di(meth)acrylate telechelate having a number-average molecular weight of 750 to 2000 g / mol, (c) 0 to 30 wt.%, preferably 0 to 20 wt.% and particularly preferably 0 wt.% of di(meth)acrylate monomer(s), (d) 1 to 12 wt.%, preferably 2 to 12 wt.% and particularly preferably 2 to 10 wt.% of at least one ABA and / or AB block copolymer, wherein the A block(s) is / are homogeneously miscible and the B block is / are not homogeneously miscible with the mixture of components (a) to (c) and (e) 0.1 to 5.0 wt.%, preferably 0.2 to 4.0 wt.% and particularly preferably 0.3 to 3.0 wt.% of at least one initiator for the radical polymerization.

[0023] Unless otherwise stated, all weight percentages herein refer to the total mass of the material.

[0024] The dental materials according to the invention contain Component (a) preferably at least one aromatic, bicyclic or tricyclic mono(meth)acrylate of formula (I) in which the variables have the following meanings: A is an aromatic group having 6 to 15 carbon atoms or a bicyclic or tricyclic aliphatic group having 7 to 10 carbon atoms, where A may be unsubstituted or substituted by one or more C 1 -C 5 alkyl groups, C 1 -C 5 alkoxy groups and / or chlorine atoms; R is hydrogen or methyl; X 1< , X 2< are each independently omitted or an ether, ester or urethane group, where X 1< is omitted if Y 1< is omitted and where X 2< is omitted if Y 2< is omitted; Y 1< , Y 2< are each independently omitted or a branched or preferably linear aliphatic hydrocarbon radical having 1 to 10 carbon atoms, which may be interrupted by 1 to 3 oxygen atoms.

[0025] (Meth)acrylate herein means acrylate, methacrylate or a mixture thereof, with methacrylate being preferred in all cases.

[0026] All formulas shown herein apply only to compounds that are compatible with chemical valence theory. The indication that a residue is interrupted, for example, by one or more oxygen atoms is to be understood as meaning that these atoms are inserted into the carbon chain of the residue. These atoms are thus bounded on both sides by C atoms and cannot be terminal. C1 residues cannot be branched or interrupted. According to conventional nomenclature, aromatic hydrocarbon residues also include residues containing aromatic and non-aromatic groups. A preferred aromatic residue is, for example, 2,2-diphenylpropane.

[0027] The preferred, particularly preferred, and very particularly preferred definitions given for the individual variables can each be selected independently of one another. Compounds in which all variables have the preferred, particularly preferred, and very particularly preferred definitions are naturally particularly suitable according to the invention.

[0028] Preferred aromatic groups A are benzene, biphenyl and 2,2-diphenylpropane:

[0029] Preferred bicyclic aliphatic groups A are bicyclo[4.4.0]decane, bicyclo[4.3.0]nonane, bicyclo[2.2.2]octane and bicyclo[2.2.1]heptane:

[0030] A preferred tricyclic aliphatic group A is tricyclo[5.2.1.0 2,6< ]decane:

[0031] Bevorzugte aromatische Mono(meth)acrylate (a) sind 2-Phenoxyethyl(meth)acrylat, 2-(o-Biphenyloxy)ethyl(meth)acrylat, 2-Hydroxy-3-phenoxypropyl-(meth)acrylat, 2-[(Benzyloxycarbonyl)-amino]-ethyl(meth)acrylat, 2-[(Benzylcarbamoyl)-oxy]-ethyl-(meth)acrylat, 1-Phenoxypropan-2-yl-(meth)acrylat und 2-(p-Cumylphenoxy)-ethyl-(meth)acrylat. Besonders geeignete aromatische Mono(meth)acrylate sind 2-Phenoxyethyl(meth)acrylat, 2-(o-Biphenyloxy)ethyl(meth)acrylat, 2-Hydroxy-3-phen-oxypropyl(meth)acrylat, 2-[(Benzyloxycarbonyl)amino]-ethyl(meth)acrylat, 1-Phenoxy-propan-2yl-(meth)acrylat, 2-(Benzyloxy)ethyl(meth)acrylat, 3-Phenoxybenzyl(meth)-acrylat, Phenoxypropyl(meth)acrylat, 2-Benzyloxyethyl(meth)acrylat, 2-Benzoyloxy-ethyl(meth)acrylat, 2-(Meth)acryloyloxybenzoesäuremethylester, 2-Phenylethyl-(meth)acrylat und / oder 2-(p-Cumylphenoxy)ethyl(meth)acrylat.

[0032] Preferred bi- or tricyclic mono(meth)acrylates (a) are tricylodecane(meth)acrylate, tricyclodecanemethyl(meth)acrylate and in particular 4,7,7-trimethylbicyclo[2.2.1]heptanyl(meth)acrylate.

[0033] The aromatic, bicyclic, or tricyclic monomethacrylates of formula (I) used in the invention are characterized by good free-radical polymerization capability. Furthermore, the polymers of these monomethacrylates exhibit comparatively low polymerization shrinkage and good mechanical properties. Due to their relatively high molecular weight (150 to 350 g / mol) and relatively nonpolar structure, the mono(meth)acrylates of formula (I) also exhibit low volatility and comparatively low viscosity.

[0034] The dental materials according to the invention contain Component (b)at least one urethane dimethacrylate telechelate having a molecular weight of 750 to 2000 g / mol. Component (b) contains two radically polymerizable groups and thus acts as a crosslinker during the polymerization of the materials of the invention, ie, it leads to the formation of polymer networks. Due to the relatively high molecular weight of component (b), polymers with a lower network density and low polymerization shrinkage are obtained.

[0035] Unless otherwise stated, the molar mass of oligomers and polymers referred to herein is the number-average molar mass, the absolute value of which can be determined using the known methods of freezing point depression (cryoscopy), boiling point elevation (ebullioscopy), or vapor pressure reduction (vapor pressure osmometry). The number-average molar mass of oligomers and polymers is preferably determined using gel permeation chromatography (GPC). This is a relative method in which molecules are separated based on their size, more specifically, their hydrodynamic volume. The absolute molar mass is determined by calibration with known standards.

[0036] Urethane dimethacrylate telechelics (b) are preferably obtained by reacting diisocyanates with diols (HO-DA-OH) and subsequently reacting the α,ω-isocyanate-functionalized urethane telechelics with HEMA or HPMA. DA preferably represents an aromatic or aliphatic hydrocarbon radical having 6 to 33 carbon atoms, preferably a divalent polycyclic hydrocarbon radical, in particular an o-diphenyl, p-diphenyl, or bisphenol A radical, or a branched or preferably linear C 2 -C 18 alkylene group. The hydrocarbon radicals may contain one or more O atoms and / or S atoms, with O atoms being preferred.

[0037] Diols of the formula HO-DA-OH according to the invention are ethoxylated or propoxylated bisphenol A, o-diphenyl or p-diphenyl with 2 to 6 ethoxy or propoxy groups, as well as C 2 -C 18 alkanediols, which may contain 1 to 4 O or S atoms in the carbon chain, cyclic or polycyclic aliphatic diols. Preferred diols are ethoxylated or propoxylated bisphenol A with 2, 3, or 4 ethoxy or propoxy groups, hexane-1,6-diol, octane-1,8-diol, nonane-1,9-diol, decane-1,10-diol, or dodecane-1,12-diol, tetra- or pentaethylene glycol. Very particular preference is given to ethoxylated or propoxylated bisphenol A with 2 or 3 ethoxy or propoxy groups, decane, undecane or dodecanediol, cyclohexanediol, norbornanediol, tricyclodecanediol and tricyclodecanedimethanol (octahydro-4,7-methano-1H-indenedimethanol).

[0038] Preferred diisocyanates are hexamethylene 1,6-diisocyanate (HMDI), 2,2,4-trimethylhexamethylene 1,6-diisocyanate (TMDI), 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethylcyclohexane (isophorone diisocyanate, IPDI), m-tetramethylxylylene diisocyanate (1,3-bis(2-isocyanato-2-ppropyl)benzene, TMXDI), toluene 2,4-diisocyanate (TDI), diphenylmethane 4,4'-diisocyanate (MDI) and 1-isocyanato-4-[(4-isocyanatocyclohexyl)methyl]cyclohexane (H 12 MDI), with IPDI being particularly preferred.

[0039] According to the invention, telechelics according to the general formula (II) are required in which the variables have the following meanings: R 1< , R 2< independently of one another are each H or methyl, preferably methyl, R 3< , R 4< independently of one another are each H or methyl, preferably methyl, x, y independently of one another are each an integer from 1 to 11, preferably 1 to 5, n 1, 2 or 3, preferably 1 Z preferably: DAa structural element derived from the diols HO-DA-OH by cleavage of the hydrogen atoms of the two hydroxyl groups.

[0040] The urethane dimethacrylate telechelates of the invention are characterized by good radical polymerization capability. They also impart good cohesive properties to the cured materials.

[0041] Monofunctional methacrylates (a), urethane dimethacrylate telechelates (b) and optionally further radically polymerizable monomers are preferably used in a ratio such that crosslinked polymers with a network density of less than vc = 300 to 5000 mol / m 3< , particularly preferably 400 to 3000 mol / m 3< are obtained. The crosslinking density is determined significantly by the ratio of crosslinking to monofunctional monomers. According to the invention, preference is given to dental materials in which the molar fraction of the crosslinking monomers is in a range from 0.1 to 0.6 and particularly preferably 0.15 to 0.45. To calculate the molar fraction, all radically polymerizable components of the materials according to the invention are used, ie in particular components (a) to (c) and optionally further radically polymerizable monomers.Crosslinking monomers are understood to be all radically polymerizable components that have two or more radically polymerizable groups, i.e., in particular, components (b) and (c). Crosslinking monomers are also referred to as polyfunctional monomers. Monofunctional monomers are monomers with only one radically polymerizable group.

[0042] The network density corresponds to the number of network nodes (in mol) per unit volume and can be calculated using dynamic mechanical measurements from the plateau value of the storage modulus G' in the elastic range. The glass transition temperature T g and the network density vc are determined using a rheometer, preferably an Anton Paar Rheometer MCR301. For this purpose, the storage and loss moduli of a test specimen (25 x 5 x 1 mm, clamped longitudinally) are measured between 25°C and 250°C (frequency 1 Hz, deformation 0.05%, heating rate 2K / min). T g is given as the maximum of the loss factor tan δ (ratio of loss modulus to storage modulus). The network density is calculated using the formula vc = G' / (RT), where G' is the storage modulus at temperature T g + 50 K, R is the general gas constant, and T is the temperature at T g + 50 K in Kelvin.

[0043] In order to further adjust the crosslinking density and to influence the mechanical properties of the polymers, the dental materials according to the invention can contain, in addition to components (a) and (b), further Di(meth)acrylate monomers (c) contain.

[0044] Preferred di(meth)acrylates (c) are bisphenol A dimethacrylate (Bis-GMA, an addition product of methacrylic acid and bisphenol A diglycidyl ether), ethoxylated or propoxylated bisphenol A dimethacrylate, such as bisphenol A dimethacrylate SR-348c (Sartomer) with 3 ethoxy groups, 2,2-bis[4-(2-methacryloxypropoxy)-phenyl]propane (UDMA, an addition product of HEMA and TMDI), V380 (an addition product of a mixture of 0.7 mol of 2-hydroxyethyl methacrylate and 0.3 mol of 2-hydroxypropyl methacrylate with 1 mol of α,α,α',α'-tetramethyl-m-xylylene diisocyanate), bis(methacryloyloxymethyl)tricyclo-[5.2.1.0 2,6< ]decane (DCP), di-, tri- or tetraethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetra(meth)acrylate, as well as glycerol di- and glycerol trimethacrylate, 1,4-butanediol dimethacrylate, 1,10-decanediol dimethacrylate (D 3 MA) and 1,12-dodecanediol dimethacrylate.

[0045] The di(meth)acrylate monomers (c) are characterized by a relatively low molecular weight. According to the invention, di(meth)acrylates (c) with a molecular weight in the range of 200 to 800 g / mol, preferably 220 to 650 g / mol, are preferred. Due to their low molecular weight compared to the urethane di(meth)acrylate telechelics (b), the di(meth)acrylate monomers (c) cause relatively strong crosslinking of the polymers and thus lead to a high network density, which can have a detrimental effect on fracture toughness. The proportion of other di(meth)acrylates is therefore limited to a maximum of 30 wt. %, preferably a maximum of 10 wt. %. According to a particularly preferred embodiment, the dental materials according to the invention contain exclusively the urethane di(meth)acrylate telechelics (b) as crosslinkers.

[0046] In addition, the dental materials according to the invention may contain other mono(meth)acrylates in addition to component (a). The proportion of other mono(meth)acrylates is preferably less than 10% by weight, with materials that do not contain any other mono(meth)acrylates being particularly preferred.

[0047] The dental materials according to the invention contain Component (d) at least one ABA and / or AB block copolymer. Block copolymers are macromolecules consisting of two or more covalently bonded homopolymer blocks.

[0048] Block copolymers preferred according to the invention can be prepared using known methods of living or controlled polymerization, for example, by radical or ionic (anionic and cationic) polymerization, with controlled radical polymerization and living anionic polymerization being preferred. However, block copolymers can also be obtained by linking end groups of homopolymers. The block copolymers used according to the invention can be di- and triblock copolymers.

[0049] AB block copolymers, for example, can be prepared by esterifying an A block with a terminal OH group to a B block containing a COOH group. End-group-functionalized homopolymer blocks can be prepared relatively easily using controlled radical polymerization methods or by endcapping in anionic polymerization.

[0050] For example, monomer A is polymerized anionically, and an OH group is introduced by endcapping. The OH end group can then be esterified, for example, with α-bromoisobutyric acid. The resulting bromine end group then serves as the starting center for the formation of the B block by ATRP (atom transfer radical polymerization) of monomer B, initiated by metal complexes, for example, of Cu(I), Ru(I), or Fe(II).

[0051] Triblock copolymers can be prepared in an analogous manner. For example, a B block is produced by anionic polymerization of monomer B via a dianion mechanism. The resulting B midblock bears an anion end group on each side, which initiates the anionic polymerization of monomer A to form the two A blocks (Method 1). Esterification of a telechelic B block, which bears a suitable functional group, e.g., an OH group, at each end, with two A blocks that are functionalized only on one side, e.g., with a COOH group, yields ABA triblock copolymers (Method 2). Finally, OH-telechelic homopolymers of monomer B can be esterified with α-bromoisobutyric acid. The two bromine end groups thus formed in homopolymer block B can then be used as starting centers for the formation of the two A blocks by ATRP (Method 3).

[0052] During the synthesis of block copolymers, polymerizable methacrylate groups can also be introduced at the terminal or side positions. These facilitate better integration of the block copolymers into the resulting polymer networks through radical copolymerization of the methacrylate groups.

[0053] The monomers are preferably chosen so that the A blocks are miscible with the resin matrix, ie the mixture of components (a) to (c), and the B block is not miscible with the resin matrix.

[0054] Miscibility is understood here in the thermodynamic sense with reference to single-phase composition. Accordingly, a miscible polymer block is defined as a polymer block made of a single monomer whose homopolymer is soluble in the resin matrix, so that the mixture has a transparency of at least 95%. If, however, the mixture is cloudy or opaque, i.e., if the transparency is less than 95%, the homopolymer, and thus the corresponding polymer block, is not miscible with the resin matrix. Transparency is measured using a spectrophotometer on 1 mm thick, mirror-polished test specimens in transmission (D65) according to ISO 10526:1999, e.g., using a Konika-Minolta CM-5 spectrophotometer.

[0055] The block copolymers significantly improve the fracture toughness of the materials according to the invention after curing. It is assumed that the immiscibility of the B blocks of the block copolymers with the other components of the compositions according to the invention causes microphase separation and thus the formation of morphologies at the nanoscale level. The macromolecules of the ABA or AB block copolymers form spherical or worm-like phases in the monomer resin or during curing through self-assembly. These phases can interact with crack tips, i.e., crack tips impinge on the phases and the fracture energy is distributed among the phases in such a way that the cracks do not propagate further through the material and do not enlarge. Crack propagation in transparent materials can be observed under an electron microscope. In fracture mechanics, the foremost part of the crack is referred to as the crack tip.

[0056] Block copolymers preferred according to the invention are AB diblock and ABA triblock copolymers.

[0057] The A block is a polymer, preferably an oligomer composed of one or more of the following monomers: cyclic, aliphatic esters or ethers, arylene oxide, alkylene oxide, radically polymerizable monomers, for example, α,β-unsaturated acids and α,β-unsaturated acid esters. Block A is preferably a poly(meth)acrylate, polylactone, phenylene oxide, or polyalkylene oxide oligomer. Block A is most preferably a polymer of caprolactone, 2,6-dialkyl-1,4-phenylene oxide, and especially of 2,6-dimethyl-1,4-phenylene oxide, ethylene oxide, propylene oxide, or (meth)acrylates. The A block is therefore preferably a polycaprolactone (PCL), poly(2,6-dimethyl-1,4-phenylene oxide), poly(ethylene oxide), poly(propylene oxide) or poly(meth)acrylate oligomer.

[0058] The B block is preferably a polysiloxane and / or a polyvinyl and / or a polyalkene and / or a polydiene oligomer. The B block is particularly preferably a polydiene oligomer, polyvinylalkanoate oligomer, or a polysiloxane oligomer according to the formula -O-(SiR 5< 2 -O) p -, in which R 5< is a linear C 1 -C 20 alkyl, branched C 3 -C 12 alkyl or C 6 -C 20 aryl group, where the individual R 5< radicals may be the same or different, and p is a number from 3 to 100, preferably a number from 10 to 50.

[0059] Most preferably, the B block is a polymer of dimethylchlorosilane, cyclotri- or cyclotetradimethoxysilane, isoprene, vinyl acetate, isobutene, cis-butadiene, or ethylene. The B block is thus preferably a poly(dimethylsiloxane) (PDMS), poly(isoprene), poly(vinyl acetate), poly(isobutene), cis-poly(butadiene), or poly(ethylene) oligomer.

[0060] The B blocks are characterized by relatively high flexibility. Flexible blocks are defined as blocks formed from monomers whose homopolymers have a glass transition temperature (TG) below 50 °C, preferably below 0 °C, and most preferably in the range of -30 to -110 °C. Block copolymers with flexible blocks improve fracture toughness, but significantly less adversely affect the flexural strength and Young's modulus of the polymers than internal plasticizers.

[0061] Polyester-polysiloxane block copolymers according to the invention are preferred according to the following general formula: (PCL) q -b-(PDMS) r -b-(PCL) q is the q is a number from 5 to 40, preferably 10 to 20, and a pure number from 10 to 100, preferably 30 to 60. (PCL) q stands for polycaprolactone, which is composed of q caprolactone monomers, and (PDMS) r for poly(dimethylsiloxane), which is composed of r dimethylsiloxane monomers. The letter b stands for block.

[0062] Further preferred are poly(meth)acrylate-polysiloxane block copolymers which contain a polymethyl methacrylate radical as A block and a polysiloxane radical as B block, wherein the polysiloxane radical is preferably as defined above and very particularly preferably a poly(dimethylsiloxane) radical.

[0063] Particularly preferred are the ABA triblock copolymers PCL-b-PDMS-b-PCL and PMMA-b-PDMS-b-PMMA with a molar ratio A:B of 0.1 to 5 and a molar mass of preferably 3 to 25 kDa, particularly preferably 4 to 20 kDa, and most particularly preferably 5 to 10 kDa. A preferred block copolymer is PCL-b-PDMS-b-PCL, with the PDMS blocks having a molar mass of approximately 3200 g / mol and the PCL blocks each having a molar mass of approximately 1600 g / mol. PCL stands for polycaprolactone, PDMS for poly(dimethylsiloxane), and PMMA for polymethyl methacrylate.

[0064] The block copolymer(s) are preferably used in an amount of 1 to 12 wt.%, particularly preferably in an amount of 2 to 10 wt.% and very particularly preferably 3 to 8 wt.%, based on the total weight of the dental material.

[0065] It has been found that the block copolymers used according to the invention significantly improve the fracture toughness of the polymer networks without compromising transparency. Furthermore, they cause only a relatively slight increase in viscosity. A further advantage of the block copolymers used according to the invention is that they can be easily mixed homogeneously with the other components of the materials, whereas the homogeneous dispersion of core-shell polymer particles is significantly more complex. Furthermore, particles tend to sediment, so that compositions based on core-shell particles are less stable. In contrast, the block copolymers can be easily incorporated into resin mixtures, allowing the materials to be easily adapted to the intended application and the desired fracture toughness and fracture energy to be adjusted.

[0066] The dental materials according to the invention contain Component(s)at least one initiator for the radical polymerization, preferably a photoinitiator. Preferred photoinitiators are benzophenone, benzoin, and their derivatives, as well as α-diketones and their derivatives, such as 9,10-phenanthrenequinone, 1-phenylpropane-1,2-dione, diacetyl, or 4,4'-dichlorobenzil. Camphorquinone (CQ) and 2,2-dimethoxy-2-phenylacetophenone are particularly preferred, and α-diketones in combination with amines as reducing agents, such as 4-(dimethylamino)benzoic acid ester (EDMAB), N,N-dimethylaminoethyl methacrylate, N,N-dimethylsym.-xylidine, or triethanolamine, are very particularly preferred. Preferred monomolecular photoinitiators for the visible range are monoacyltrialkyl-, diacyldialkyl- and tetraacylgermanium as well as tetraacylstannanes, such as benzoyltrimethylgermanium, dibenzoyldiethylgermanium, bis(4-methoxybenzoyl)diethylgermanium, tetrakis(2-methylbenzoyl)germane or tetrakis(mesitoyl)stannane.Mixtures of the different photoinitiators can also be used, such as bis(4-methoxybenzoyl)diethylgermanium in combination with camphorquinone and 4-dimethylaminobenzoic acid ethyl ester.

[0067] Preferred initiators for curing the dental materials according to the invention with UV light are Norrish type I photoinitiators, especially acetophenones, e.g. 2,2-diethoxy-1-phenylethanone, benzoin ethers e.g. Irgacure 651 (dimethyl benzil ketal), hydroxyalkylphenyl acetophenones, e.g. Irgacure 184 (1-hydroxy-cyclohexyl phenyl ketone), acyl or bisacylphosphine oxides, e.g. Irgacure TPO (2,4,6-trimethylbenzoyldiphenylphosphine oxide) and Irgacure 819 (bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide). Other preferred photoinitiators are 2-benzyl-2-(dimethylamino)-4'-morpholinobutyrophenone (Irgacure 369) and 1-butanone-2-(dimethylamino)-2-(4-methylphenyl)methyl-1-4-(4-morpholinyl)phenyl (Irgacure 379). Particularly preferred photoinitiators are bis(4-methoxybenzoyl)diethylgermanium, Irgacure TPO and Irgacure 819, as well as camphorquinone / 4-(dimethylamino)benzoic acid esters.For post-coating, it is advantageous to use two photoinitiators that differ in their absorption ranges, such as Irgacure TPO and camphorquinone / 4-(dimethylamino)benzoic acid ester.

[0068] The dental materials according to the invention can alternatively or additionally contain thermal initiators, e.g., azo compounds such as 2,2'-azobis(isobutyronitrile) (AIBN) or azobis(4-cyanovaleric acid), or peroxides such as dibenzoyl peroxide, dilauroyl peroxide, tert-butyl peroctoate, tert-butyl perbenzoate, or di-(tert-butyl) peroxide. Combinations with aromatic amines can also be used to accelerate initiation using peroxides. Preferred redox systems are combinations of dibenzoyl peroxide with amines, such as N,N-dimethyl-p-toluidine, N,N-dihydroxyethyl-p-toluidine, ethyl p-dimethylaminobenzoate, or structurally related systems.

[0069] The initiator(s) are preferably used in a total amount of 0.1 to 5.0 wt.%, particularly preferably 0.2 to 4 wt.% and very particularly preferably 0.3 to 3.0 wt.%, these amounts including all initiator components, such as reducing agents.

[0070] The dental materials according to the invention can also contain a certain proportion of one or more core-shell polymers to further improve fracture toughness and impact strength ( component (f)). Preference is given to core-shell polymers (CSP) with a soft polymer core, e.g. made of a cross-linked butyl acrylate, and a relatively hard polymer shell, e.g. PMMA. Soft or flexible polymers are understood to be polymers with a glass transition temperature TG below 50 °C, preferably below 0 °C and very particularly preferably in the range from -30 to -110 °C. A preferred concrete example is PDMS with a TG of approx. -110 °C. Hard polymers are understood to be polymers with a glass transition temperature above 50 °C and preferably above 80 °C. A preferred concrete example is PMMA with a TG of 100 °C.

[0071] The fracture toughness-modifying effect of CSP particles in radical dimethacrylate polymer networks depends primarily on the type of CSP particles, the particle size, the crosslinking density, and the core-to-shell weight ratio, which preferably ranges from 1:1 to 200:1. The crosslinking density is largely determined by the proportion of crosslinking monomers in the particle core. This preferably ranges from 1 to 10 wt. %, based on the mass of the core. According to the invention, particles with a particle size of 0.20 to 5.0 µm are preferred.

[0072] Preferred according to the invention are CSP particles with a core made of soft plastics such as polybutadiene, polyisoprene, polybutyl acrylate, MMA-butadiene-styrene copolymers (MBS), or polydimethylsiloxane, and a shell made of hard plastics such as PMMA or MMA-styrene copolymer. CSP particles suitable according to the invention are commercially available, e.g., from Arkema (Clearstrength), Soken (Chemisnow), or Kaneka (e.g., M521 or M210).

[0073] Core-shell polymers can be added in an amount of up to 15 wt.%. A disadvantage of using core-shell polymers is that they can severely impair the transparency of the compositions, which negatively affects the depth of cure during photopolymerization and, in the case of dental moldings, also negatively affects the aesthetics. According to the invention, materials containing a maximum of 5 wt.% and, particularly preferably, no core-shell particles are therefore preferred. When incorporating the CSP particles into the dental material, care must be taken to ensure good dispersion.

[0074] To influence the mechanical properties, the dental materials according to the invention can be combined with inorganic particulate Fillers (g) be reinforced.

[0075] Preferred inorganic fillers are oxides such as SiO 2 , ZrO 2 and TiO 2 or mixed oxides of SiO 2 , ZrO 2 , ZnO and / or TiO 2 , nanoparticulate or microfine fillers such as fumed silica or precipitated silica, glass powders such as quartz, glass ceramic, borosilicate or X-ray opaque glass powders, preferably barium or strontium aluminum silicate glasses, and X-ray opaque fillers such as ytterbium trifluoride, tantalum(V) oxide, barium sulfate or mixed oxides of SiO 2 with ytterbium(III) oxide or tantalum(V) oxide. Furthermore, the dental materials according to the invention can contain fibrous fillers, nanofibers, whiskers or mixtures thereof. According to a preferred embodiment, the materials according to the invention do not contain fluoroaluminosilicate glasses, calcium aluminum silicate glasses or other fillers that react with organic acids in the sense of an acid-base reaction.

[0076] Preferably, the oxides have a particle size of 0.010 to 15 µm, the nanoparticulate or microfine fillers have a particle size of 10 to 300 nm, the glass powders have a particle size of 0.01 to 15 µm, preferably 0.2 to 1.5 µm, and the X-ray opaque fillers have a particle size of 0.2 to 5 µm.

[0077] Particularly preferred fillers are mixed oxides of SiO 2 and ZrO 2 , with a particle size of 10 to 300 nm, glass powder with a particle size of 0.2 to 1.5 µm, in particular X-ray opaque glass powders, e.g. of barium or strontium aluminum silicate glasses, and X-ray opaque fillers with a particle size of 0.2 to 5 µm, in particular ytterbium trifluoride and / or mixed oxides of SiO 2 with ytterbium(III) oxide.

[0078] To improve the bond between the filler particles and the crosslinked polymerization matrix, SiO 2 -based fillers can be surface-modified with methacrylate-functionalized silanes. A preferred example of such silanes is 3-methacryloyloxypropyltrimethoxysilane. Functionalized acid phosphates, such as 10-methacryloyloxydecyl dihydrogen phosphate, can also be used to surface-modify non-silicate fillers such as ZrO 2 or TiO 2.

[0079] Further preferred fillers are particulate waxes, in particular carnauba wax, preferably with a particle size of 1 to 10 µm, uncrosslinked or partially crosslinked polymethyl methacrylate (PMMA) particles, preferably with a particle size of 500 nm to 10 µm, and polyamide-12 particles, preferably with a particle size of 5 to 10 µm.

[0080] In addition, the dental materials according to the invention can contain a so-called prepolymer filler or isofiller, ie, a ground composite that preferably has a broad particle size distribution, e.g., with particle sizes of 0.05 to 20 µm, in particular about 0.1 to about 10 µm. The prepolymer filler or isofiller is preferably surface-modified, in particular silanized.

[0081] Unless otherwise stated, all particle sizes herein are weight-average particle sizes. The particle size determination in the range from 0.1 µm to 1000 µm is carried out using static light scattering, preferably with an LA-960 static laser scattering particle size analyzer (Horiba, Japan). The light sources used are a laser diode with a wavelength of 655 nm and an LED with a wavelength of 405 nm. The use of two light sources with different wavelengths enables the entire particle size distribution of a sample to be measured in a single measurement run, with the measurement being performed as a wet measurement. For this purpose, a 0.1 to 0.5% aqueous dispersion of the filler is prepared, and its scattered light is measured in a flow cell. The scattered light analysis for calculating particle size and particle size distribution is carried out according to the Mie theory according to DIN / ISO 13320.

[0082] Particle sizes smaller than 0.1 µm are preferably determined using dynamic light scattering (DLS). Particle size measurements in the range from 5 nm to 0.1 µm are preferably performed using dynamic light scattering (DLS) of aqueous particle dispersions, preferably using a Malvern Zetasizer Nano ZS (Malvern Instruments, Malvern UK) with a He-Ne laser with a wavelength of 633 nm and a scattering angle of 90° at 25°C.

[0083] Light scattering decreases with decreasing particle size. Particle sizes smaller than 0.1 µm can also be determined using SEM or TEM spectroscopy. Transmission electron microscopy (TEM) is preferably performed using a Philips CM30 TEM at an accelerating voltage of 300 kV. For sample preparation, drops of the particle dispersion are deposited onto a 50 Å thick copper grid (300 mesh) coated with carbon, and the solvent is then evaporated.

[0084] Fillers are divided into macrofillers and microfillers according to their particle size. Fillers with an average particle size of 0.2 to 10 µm are referred to as macrofillers and fillers with an average particle size of approximately 5 to 100 nm are referred to as microfillers. Macrofillers are obtained, for example, by grinding quartz, X-ray opaque glasses, borosilicates or ceramics and usually consist of splinter-like pieces. The preferred microfillers are pyrogenic SiO 2 or precipitated silica, or mixed oxides, e.g. SiO 2 -ZrO 2 , which are obtainable by hydrolytic co-condensation of metal alkoxides. The microfillers preferably have an average particle size of approximately 5 to 100 nm. Microfillers. Fillers with a smaller particle size have a greater thickening effect.

[0085] In a preferred embodiment, the dental materials according to the invention contain a mixture of two or more fillers, in particular two or more fillers with different particle sizes. It has been found that the use of such filler mixtures does not excessively increase the viscosity of the materials and the compositions are therefore readily processable using additive methods, such as stereolithography. The total filler content is preferably in a range from 0 to 20 wt.%, particularly preferably from 0 to 10 wt.%.

[0086] The dental materials according to the invention may further comprise one or more UV absorber (h)The UV absorber serves to reduce the penetration depth of the light and thus the polymerization depth during the light-induced curing of the composition according to the invention. This proves particularly advantageous in stereolithographic applications, since only thin layers are to be cured in stereolithography. The use of a UV absorber can improve the precision of stereolithographic processes.

[0087] Bevorzugt sind UV-Absorber auf der Basis von Benzotriazol, Benzophenon oder Triazine. Besonders bevorzugte UV-Absorber sind 2,2'-Methylenbis[6-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol], 2,2',4,4'-Tetrahydroxybenzophenon, 2-tert-Butyl-6-(5-chloro-2H-benzotriazol-2-yl)-4-methylphenol (Bumetrizol), 2,2'-Benzol-1,4-diylbis(4h-3,1-benzoxazin-4-on), 2-(4,6-Bis-(2,4-dimethylphenyl)-1,3,5-triazin-2-yl)-5-(octyloxy)-phenol, 2-(2-Hydroxy-5-methylphenyl)benzotriazol, 2-(2-Hydroxyphenyl)benzotriazol, 2-(2H-Benzotriazol-2-yl)-6-dodecyl-4-methylphenol, 2-(2'-Hydroxy-3', 5'-di-t-butylphenyl)-5-chlorobenzotriazole, 2,2'-Dihydroxy-4-methoxybenzophenon und 2,2'-Dihydroxy-4,4'-dimethoxybenzophenon.Further preferred are so-called hindered amine light stabilizers such as bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate, bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, and bis(1,2,2,6,6-pentamethyl-4-piperidyl)-[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butylmalonate. Bumetrizole and 2,2',4,4'-tetrahydroxybenzophenone are particularly preferred UV absorbers.

[0088] The UV absorber preferably has an absorption maximum that corresponds to the wavelength of the light used for curing. UV absorbers with an absorption maximum in the range of 320 to 500 nm, preferably 380 to 480 nm, are advantageous, with UV absorbers with an absorption maximum below 400 nm being particularly preferred.

[0089] UV absorbers are optionally used in an amount of preferably 0 to 1.0 wt.%, particularly preferably 0.01 to 0.5 wt.%. Bumetrizole is preferably used in an amount of 0.01 to 0.2 wt.%, particularly preferably 0.02 to 0.15 wt.%, and 2,2',4,4'-tetrahydroxybenzophenone in an amount of 0.01 to 0.07 wt.%. All data refer to the total weight of the material. Dental materials that do not contain UV absorbers are preferred.

[0090] The dental materials according to the invention may also contain one or more optical brighteners (i)contained. Preferred according to the invention are optical brighteners that absorb light in the UV range, i.e. light with a wavelength below 400 nm. By adding an optical brightener, the penetration depth of the light and thus the curing depth can be reduced, thus increasing the precision in stereolithographic processes. Particular preference is given to optical brighteners that are able to re-emit the light absorbed in the UV range as light with a wavelength of 400 to 450 nm. Such optical brighteners increase the reactivity of the materials by emitting the absorbed short-wave light as longer-wave blue light due to their fluorescence, thus providing additional light output for photoinitiation. Preferred optical brighteners according to the invention are 2,5-bis(5-tert-butyl-benzoxazol-2-yl)thiophene and fluorescent agents in the form of terephthalic acid derivatives, such as2,5-Dihydroxyterephthalic acid diethyl ester or diethyl 2,5-dihydroxyterephthalate.

[0091] The optical brightener(s) are optionally used in an amount of preferably 0 to 0.1 wt.%, particularly preferably 0.001 to 0.05 wt.%, and most preferably 0.002 to 0.02 wt.%, each based on the total weight of the material. Dental materials that do not contain an optical brightener are preferred.

[0092] Optical brighteners can be used in combination with UV absorbers. In this case, the weight ratio of UV absorber to optical brightener is preferably in a range from 2:1 to 50:1, more preferably 2:1 to 30:1, and most preferably 2:1 to 5:1 or 10:1 to 25:1. Combinations containing 2,2',4,4'-tetrahydroxybenzophenone or bumetrizole as UV absorber and 2,5-bis(5-tert-butylbenzoxazol-2-yl)thiophene as optical brightener are preferred. Very particularly preferred is the combination of 2,2',4,4'-tetrahydroxybenzophenone and 2,5-bis(5-tert-butyl-benzoxazol-2-yl)thiophene in a weight ratio of 2:1 to 10:1, preferably 2:1 to 5:1, or the combination of bumetrizole and 2,5-bis(5-tert-butyl-benzoxazol-2-yl)thiophene in a weight ratio of 5:1 to 30:1, preferably 10:1 to 20:1.

[0093] The dental materials according to the invention can also contain further Additive(j) contain, in particular, stabilizers, colorants, plasticizers, thixotropic additives, microbicidal agents and / or blowing agents.

[0094] The dental materials according to the invention preferably contain one or more Stabilizers. These are radical-scavenging substances that prevent premature polymerization. Stabilizers are also known as polymerization inhibitors. These inhibitors, or stabilizers, improve the storage stability of the materials.

[0095] Preferred inhibitors are phenols, such as hydroquinone monomethyl ether (MEHQ) or 2,6-di-tert-butyl-4-methylphenol (BHT). Phenols are preferably used in a concentration of 0.001 to 0.50 wt.%. Other preferred inhibitors are phenothiazine, 2,2-diphenyl-1-picrylhydrazyl (DPPH), galvinoxyl, triphenylmethyl, and 2,2,6,6-tetramethylpiperindin-1-oxyl (TEMPO) radicals. These inhibitors are preferably used in an amount of 0.001 to 0.02 wt.%. Polymerization only occurs when these additives are consumed. The amounts stated refer in each case to the total mass of the material. A mixture of inhibitors containing at least one phenol and at least one of the other initiators is preferably used.

[0096] In addition, the dental materials according to the invention can also Colorantscontained, preferably in a concentration of 0.0001 to 0.5 wt.%. The colorants primarily serve aesthetic purposes. Colorants preferred according to the invention are organic dyes and pigments, in particular azo dyes, carbonyl dyes, cyanine dyes, azomethines and methines, phthalocyanines and dioxazines. Particular preference is given to dyes that are soluble in the materials according to the invention, in particular azo dyes. Also suitable as colorants are inorganic and in particular organic pigments that can be easily dispersed in the dental materials according to the invention. Preferred inorganic pigments are metal oxides or hydroxides, such as titanium dioxide or ZnO as white pigments, iron oxide (Fe 2 O 3 ) as red pigment or iron hydroxide (FeOOH) as yellow pigment. Preferred organic pigments are azo pigments, such as monoazo yellow and orange pigments, disazo pigments or β-naphthol pigments, and non-azo or polycyclic pigments, such asPhthalocyanine, quinacridone, perylene, and flavanthrone pigments. Azo and non-azo pigments are particularly preferred.

[0097] In addition, the dental materials according to the invention may contain one or more plasticizers Plasticizers prevent the polymers from becoming brittle after photochemical curing and possible drying. Plasticizers also ensure sufficient flexibility. Plasticizers are preferably added in a concentration of 0.2 to 5 wt.%. Preferred plasticizers are phthalates, such as dibutyl or dihexyl phthalate; non-acidic phosphates, such as tributyl or tricresyl phosphate; n-octanol; glycerol; or polyethylene glycols. Tartaric acid or citric acid esters, such as citric acid triesters, are particularly preferred, as they are characterized by good biocompatibility.

[0098] The dental materials according to the invention may further comprise one or more Thixotropic additivesThese additives thicken the materials and can thus, for example, prevent sedimentation of the fillers. Materials containing fillers, in particular, therefore preferably contain at least one thixotropic additive. Preferred thixotropic additives are polymers containing OH groups, such as cellulose derivatives, and inorganic substances, such as phyllosilicates. In order not to increase the viscosity of the materials too much, the dental materials according to the invention preferably contain only 0 to 3.0 wt.%, more preferably 0 to 2.0 wt.%, and most preferably 0.1 to 2.0 wt.% of thixotropic additive, based on the total weight of the material.

[0099] Certain fillers, such as highly dispersed SiO 2 , i.e., SiO 2 with a small primary particle size (< 20 nm) and a high surface area (> 100 m 2 ), also have a thixotropic effect. Such fillers can replace thixotropic additives.

[0100] The rheological properties of the dental materials according to the invention are adapted to the desired application. Materials for stereolithographic processing are preferably adjusted so that their viscosity is in the range from 50 mPa s to 100 Pa s, preferably 100 mPa s to 10 Pa s, particularly preferably 100 mPa s to 5 Pa s. The viscosity is determined at 25°C using a cone-and-plate viscometer (shear rate 100 / s). The dental materials according to the invention particularly preferably have a viscosity of <10 Pa s and very particularly preferably <5 Pa s at 25°C. The viscosity is preferably determined using an Anton Paar MCR 302 viscometer with a CP25-2 cone-and-plate measuring device and a measuring gap of 53 µm in rotation at a shear rate of 100 / s. Due to their low viscosity, the dental materials according to the invention are particularly suitable for use with generative manufacturing processes, such as3D printing or stereolithography. The processing temperature is preferably in the range of 10 to 70°C, particularly preferably 20 to 30°C.

[0101] According to the invention, dental materials with the following composition are particularly preferred: (a) 30 to 70 wt.%, preferably 30 to 61 wt.%, particularly preferably 40 to 60 wt.% of at least one aromatic, bicyclic or tricyclic mono(meth)acrylate, (b) 20 to 60 wt.%, preferably 30 to 55 wt.% and particularly preferably 33 to 55 wt.% of at least one urethane di(meth)acrylate telechelate having a number-average molecular weight of 750 to 2000 g / mol, (c) 0 to 30 wt.%, preferably 0 to 20 wt.%, and particularly preferably 0 wt.% of di(meth)acrylate monomer(s), (d) 1 to 12 wt.%, preferably 2 to 12 wt.%, particularly preferably 2 to 10 wt.% of at least one ABA or AB block copolymer, (e) 0.1 to 5.0 wt.%, preferably 0.2 to 4.0 wt.% and particularly preferably 0.3 to 3.0 wt.% of at least one initiator for the radical polymerization, (f) 0 to 15 wt.%, preferably 0 to 5 wt.% and particularly preferably 0 wt.% core-shell polymer particles, (g) 0 to 20 wt.%, preferably 0 to 15 wt.% and particularly preferably 0 to 10 wt.% filler, (h) 0 to 1.0 wt.-%, preferably 0 to 0.7 wt.% and particularly preferably 0 to 0.5 wt.% UV absorber, (i) 0 to 0.5 wt.%, preferably 0 to 0.1 wt.% and particularly preferably 0 to 0.05 wt.% optical brightener and (j) 0 to 15 wt.%, preferably 0 to 10 wt.% and particularly preferably 0.05 to 5 wt.% of further additives. .

[0102] Dental materials with the following composition are particularly preferred: (a) 30 to 70 wt.%, preferably 30 to 61 wt.% and particularly preferably 40 to 60 wt.% of at least one mono(meth)acrylate of the formula (I), (b) 20 to 60 wt.%, preferably 30 to 55 wt.% and particularly preferably 33 to 55 wt.% of at least one urethane di[meth]acrylate telechelate of the formula (II), (c) 0 to 30 wt.%, preferably 0 to 20 wt.% and particularly preferably 0 wt.% of further di(meth)acrylate monomers, (d) 2 to 12 wt.%, preferably 2 to 10 wt.% and particularly preferably 3 to 8 wt.% of at least one ABA or AB block copolymer, (e) 0.1 to 5.0 wt.%, preferably 0.2 to 4 wt.% and particularly preferably 0.3 to 3.0 wt.% of at least one photoinitiator, (f) 0 to 15 % by weight, preferably 0 to 5 % by weight and particularly preferably 0 % by weight of core-shell polymer particles, (g) 0 to 20 % by weight, preferably 0 to 15 % by weight and particularly preferably 0 to 10 % by weight of filler, (h) 0 to 1.0 % by weight, preferably 0 to 0.7 % by weight and particularly preferably 0 to 0.5 % by weight of UV absorber, (i) 0 to 0.5 % by weight.-%, preferably 0 to 0.1 wt.% and particularly preferably 0 to 0.05 wt.% optical brightener and (j) 0 to 15 wt.%, preferably 0 to 10 wt.% and particularly preferably 0.02 to 5 wt.% of further additives. .

[0103] Unless otherwise stated, all weight percentages herein refer to the total mass of the dental material.

[0104] Particularly preferred according to the invention are dental materials which (a) 40 bis 61 Gew.-% an 2-Phenoxyethyl(meth)acrylat, 2-(o-Biphenyloxy)ethyl-(meth)acrylat, 2-Hydroxy-3-phenoxypropyl-(meth)acrylat, 2-[(Benzyloxycarbonyl)amino]ethyl(meth)acrylat, 1-Phenoxypropan-2yl-(meth)acrylat, 2-(Ben-zyloxy)-ethyl(meth)acrylat, 2-(Methaacryloyloxy)ethyl(meth)acrylat, 3-Phenoxy-benzyl(meth)acrylat, Phenoxypropyl(meth)acrylat, 2-Benzyloxyethyl(meth)-acrylat, 2-Benzoyloxyethyl(meth)acrylat, 2-(Meth)acryloyloxybenzoesäure-methylester, 2-Phenylethyl(meth)acrylat, Tricyclodecan(meth)acrylat, Tricyclo-decanmethyl(meth)acrylat und / oder 2-(p-Cumylphenoxy)ethylmethacrylat, (b) 33 bis 55 Gew.-% of at least one urethane di(meth)acrylate telechelate having a number-average molecular weight of 750-2000 g / mol and having at least 4 urethane groups, prepared by reacting 1 mol of ethoxylated or propoxylated bisphenol A, decane or dodecanediol with 2 mol of isophorone diisocyanate (IPDA) and subsequent reaction with 2 mol of 2-hydroxyethyl methacrylate (HEMA) or hydroxypropyl methacrylate (HPMA), (c) 0 wt.% of further di(meth)acrylate monomers, (d) 2 to 10 wt.% of at least one ABA or AB block copolymer, wherein the A block consists of oligomeric polycaprolactone, poly(2,6-dimethyl-1,4-phenylene oxide), poly(ethylene oxide), poly(propylene oxide) or poly(meth)acrylate building blocks and the B block consists of poly(dimethylsiloxane), Poly(isoprene), poly(vinyl acetate), poly(isobutene), cis-poly(butadiene) or poly(ethylene) building blocks, (e) 0% core-shell polymers, (f) 0.1 to 5.0% by weight of at least one photoinitiator and (g) 0.2 to 5% by weight of one or more further additives..

[0105] The dental materials according to the invention are characterized by high fracture toughness and fracture energy, as well as good flexural strength and a relatively high modulus of elasticity, measured at 37°C in water, which corresponds to oral conditions. The materials also exhibit high transparency and low viscosity. A particularly advantageous feature is that the dental materials retain high transparency and low inherent color even after curing.

[0106] In contrast, the core-shell polymers used in the prior art as impact modifiers generally result in a more or less pronounced reduction in transparency, which is disadvantageous for additive manufacturing processes. It has been found that the block copolymers (d) enable an improvement in fracture toughness, but result in only a relatively minor impairment of transparency compared to core-shell polymers. Furthermore, since a significantly lower amount of block copolymers (d) is required to achieve the desired fracture toughness compared to core-shell polymers, the block copolymers (d) enable the production of materials with high transparency that are ideally suited for additive manufacturing processes.

[0107] The fracture toughness-enhancing effect of the block polymers (d) is particularly pronounced when the crosslinking density vc of the materials is in the range of 300 to 5000 mol / m 3 and preferably 400 to 3000 mol / m 3 . While a higher crosslinking density increases the flexural strength and the Young's modulus, it leads to a lower fracture strength of the polymers. A reduction in the crosslinking density increases the fracture toughness but has a detrimental effect on the flexural strength and the Young's modulus.

[0108] A crosslinking density in the preferred range is achieved by using urethane di(meth)acrylate telechelics (b) with a number-average molecular weight of 750 to 2000 g / mol as crosslinkers, whereby the crosslinking density can be finely adjusted by adding small amounts of monomeric di(meth)acrylates.

[0109] According to the invention, materials with a transparency of ≥ 60%, preferably ≥ 70%, and most preferably ≥ 80%, and a viscosity of ≤ 10.0 Pa s, preferably ≤ 5.0 Pa s, are particularly preferred. Transparency is measured as described above according to ISO 10526:1999. Viscosity is determined using a cone-and-plate viscometer as described above.

[0110] After curing, the materials according to the invention exhibit a fracture toughness K max of greater than 1.1 MPa m 1 / 2< , preferably greater than 1.2 MPa m 1 / 2< , particularly preferably greater than 1.4 MPa m 1 / 2< , and a fracture energy FW greater than 250 J / m 2< , preferably greater than 300 J / m 2< , particularly preferably greater than 400 J / m 2< . Workpieces made from these materials thus withstand a high degree of deformation without fracture. High transparency combined with high fracture energy cannot be achieved with core-shell polymers.

[0111] The determination of fracture toughness K max and fracture energy FW is carried out in accordance with ISO 20795-1:2013 in a 3-point bending test with a span of 32 mm. The determination of K max and FW is based on the theoretical principles of the stress intensity factor K 1C . Fracture toughness K max is the maximum stress intensity factor, also known as the stress intensity factor at maximum load, and is calculated as follows: with where and W is the specimen height (= 8 mm), B is the specimen thickness (= 4 mm), a is the crack length (= 3 mm + crack depth with razor blade), S is the span (= 32 mm) and P max is the maximum pressure during the test.

[0112] The fracture work FW (fracture work, total fracture work) is calculated as follows: where U is the total energy required for the fracture of the sample (integral of the load / displacement graph) and is needed to create the two new fracture surfaces B (Π -< - a ). This parameter describes the material's resistance to crack propagation.

[0113] After curing, the materials according to the invention exhibit good flexural strength and a relatively good flexural modulus, as well as good fracture toughness and high fracture energy. Molded parts obtained by curing the materials according to the invention exhibit high rigidity and high resistance to deformation without breaking. Materials which, after curing, have a flexural strength, determined according to ISO 20795-1:2013, of at least 40 MPa, more preferably 50 MPa or more, and most preferably 60 MPa or more are preferred. Furthermore, the cured materials preferably exhibit a flexural modulus, determined according to ISO 20795-1:2013, of at least 1000 MPa, preferably 1300 MPa or more, more preferably 1500 MPa or more, most preferably 2000 MPa or more, and most preferably 2500 MPa.In addition, the materials have a fracture toughness K max of 1.1 MPa m 1 / 2< or greater, preferably 1.2 MPa m 1 / 2< or greater, particularly preferably 1.4 MPa m 1 / 2< or greater, and a fracture work FW of 250 J / m 2< or greater, preferably 300 J / m 2< or greater, particularly preferably 400 J / m 2< or greater. Accordingly, materials with a flexural strength of 60 to 100 MPa, a flexural modulus of 2000 to 2500 MPa, a fracture toughness K max of 1.4 to 2.5 MPa m 1 / 2< and a fracture work FW of 400 to 800 J / m 2< are particularly preferred.

[0114] According to a particularly preferred embodiment of the invention, the materials after hardening have a flexural strength of 50 MPa or greater, measured according to ISO220795-1:2013, and a fracture energy of 250 J / m 2< or greater and a K max value (maximum stress intensity factor) of at least 1.2 MPa·m 0.5< .

[0115] Due to the above properties, the materials according to the invention are outstandingly suitable for use as dental materials, e.g., as denture materials or veneering materials, and in particular for the production or repair of dental moldings, such as dental restorations, dentures, artificial teeth, inlays, onlays, crowns, bridges, drilling templates, splints (bite splints), trial pieces, and orthodontic devices, such as plastic correction splints, so-called aligners, and positioners. The moldings mentioned are also the subject of the invention. The dental materials according to the invention are preferably used extraorally, i.e., not therapeutically.

[0116] The present invention further provides a method for producing dental moldings, in particular for producing the aforementioned dental components, in which a composition according to the invention is cured with the aid of light to produce the dental molding. The production or repair of dental moldings is preferably carried out extraorally, particularly preferably by a generative process, most preferably by 3D printing or a lithography-based process, such as stereolithography.

[0117] The stereolithographic production of molded parts is preferably carried out by directly or indirectly digitizing the tooth or teeth to be restored on the computer to create a virtual image of the tooth situation, then using this image to construct a model of the dental restoration or prosthesis on the computer and then producing this model by generative stereolithographic manufacturing.

[0118] After creating the virtual model of the dental workpiece to be manufactured, the composition according to the invention is polymerized by selective light irradiation. The dental restoration or prosthesis is preferably built up layer by successively polymerizing a large number of thin layers with the desired cross-section. After the layer-by-layer construction of the restoration or prosthesis, excess residual resin is preferably removed. This can be done by suitable mechanical processes (e.g. spinning or blowing off) or by treatment with a suitable solvent, such as an alcohol such as ethanol or isopropanol, a ketone such as acetone or an ester such as ethyl acetate. This is then preferably followed by post-treatment by heating or, more preferably, by irradiating the workpiece with light of a suitable wavelength, such as irradiation with light with an intensity of, for example, 160 mW / cm2< at 405 nm.When using two photoinitiators, irradiation with two different wavelengths is advantageous. Preferably, the workpiece is heated to a temperature above 50 °C simultaneously or in a subsequent step. Photochemical and / or thermal post-treatment can improve the mechanical properties.

[0119] The invention is explained in more detail below using examples. Examples of implementation Example 1 Synthesis of 2-(2-biphenyloxy)-ethyl methacrylate (aromatic monomethacrylate) 1st stage: 2-(2-biphenyl)oxyethanol

[0120]

[0121] In a jacketed reactor, 2.55 kg (15.0 mol) of 2-phenylphenol, 0.12 kg (0.75 mol) of potassium iodide, and 0.17 kg (0.75 mol) of benzyltriethylammonium chloride were added to a solution of 0.90 kg (22.5 mol) of sodium hydroxide in 15.0 kg of water. The solution was heated to 60 °C (internal temperature), and the dropwise addition of 1.81 kg (22.5 mol) of 2-chloroethanol was initiated. After the addition was complete, the mixture was stirred at 60 °C for 48 h. For workup, the mixture was diluted with 6.0 L of toluene, and after phase separation, the aqueous phase was extracted twice with 3.0 L of toluene each time. The combined toluene phases were washed three times with 4.0 L of 1N sodium hydroxide solution, three times with 4.0 L of 1N hydrochloric acid, and three times with 3.0 L of water. The toluene was distilled off in vacuo. After recrystallization from toluene, 2.77 kg (86% yield) of 2-(2-biphenyl)oxyethanol was obtained as a colorless, crystalline solid (mp: 74-75 °C) with a purity of >99% (GC).

[0122] 1< H-NMR (400 MHz, CDCl 3 ) δ (ppm) = 1.86 (t, J = 6.5 Hz, 1H, OH), 3.78-3.81 (m, 2H, HOCH 2 ), 4.04 (t, J = 4.6 Hz, 2H, OCH 2 ), 6.98-7.08, 7.28-7.34, 7.38-7.42 and 7.50-7.52 (4m, 2H, 3H, 2H, 2H, =CH).

[0123] 13< C-NMR (100 MHz, CDCl 3 ) δ (ppm) = 61.4 and 70.3 (OCH 2 ), 113.5 (C-6), 121.7 (C-4), 127.1, 128.7 and 131.0 (C-3, C-5, C-4'), 128.1 and 129.4 (C-2', C-3', C-5', C-6'), 131.5 and 138.4 (C-2, C-1'), 155.4 (C-1).

[0124] IR (diamond ATR): v (cm -1< ) ​​= 3329 (br, m, OH), 3056 (m, =CH), 2918 and 2866 (m, CH 2 ), 1596 and 1584 (m, C=C), 1502 and 1483 (s, aromatic), 1431 (s, CH 2 ), 1260 and 1077 (s, COC), 1054 (s, COH), 749, 730 and 700 (vs, =CH). 2nd step: 2-(2-biphenyloxy)-ethyl methacrylate

[0125]

[0126] In a jacketed reactor, 0.75 kg (7.4 mol) of triethylamine, 37.9 g (0.31 mol) of 4-dimethylaminopyridine, and 0.35 g of 2,6-di-tert-butyl-4-methylphenol were added to a solution of 1.33 kg (6.2 mol) of 2-(2-biphenyl)oxyethanol in 13.0 L of methylene chloride. At 0 °C (internal temperature), a solution of 1.14 kg (7.4 mol) of methacrylic anhydride was added dropwise, and the mixture was stirred for a further 2 hours at this temperature and for 20 hours at 20 °C. The solution was then washed three times with 4.0 L of 1N hydrochloric acid, three times with 4.0 L of 1N sodium hydroxide solution, and three times with 4.0 L of water. The organic phase was stabilized with 0.09 g of phenothiazine. After solvent removal, 1.71 kg (98% yield) of 2-(2-biphenyloxy)ethyl methacrylate (BPOEMA) was obtained as an almost colorless oil with a purity of 96.45% (GC).

[0127] 1< H-NMR (400 MHz, CDCl 3 ) δ (ppm) = 1.93 (s, 3H, CH 3 ), 4.19 and 4.41 (2 t, each J = 4.8 Hz, each 2H, OCH 2 ), 5.55 and 6.08 (2 s, each 1H, =CH 2 ), 6.95-7.06, 7.26-7.30, 7.33-7.37 and 7.52-7.55 (4m, 2H, 2H, 3H, 2H, =CH).

[0128] 13< C-NMR (100 MHz, CDCl 3 ) δ (ppm) = 18.3 (CH 3 ), 63.0 and 66.5 (OCH 2 ), 113.1 (C-6), 121.7 (C-4), 126.0 (C=CH 2 ), 126.9, 128.6, 131.1 (C-3, C-5, C-4'), 127.9 and 129.6 (C-2', C-3', C-5', C-6'), 131.3 and 138.3 (C-2, C-1'), 136.1 (C=CH 2 ), 155.4 (C-1), 167.2 (C=O).

[0129] IR (diamond ATR): v (cm -1< ) ​​= 3027 (w, =CH), 2955 and 2900 (w, CH 2 , CH 3 ), 1716 (vs, C=O), 1636 (m, C=C methacrylate), 1598 and 1584 (m, C=C aromatic), 1504 and 1482 (m, s, aromatic), 1434 (s, CH 2 , CH 3 ), 1261 and 1125 (s, COC ether), 1157 (vs, COC ester), 939 (s, =CH methacrylate), 751, 733 and 697 (vs, =CH aromatic).

[0130] The rotational viscosity of BPOEMA was determined using an MCR rheometer (Anton Paar GmbH, Austria) to be η = 0.01 Pa s. The refractive index of BPOEMA was determined using an ABBE 5 refractometer (Bellingham+Stanley, UK) to be n D 20< = 1.5729. The density of BPOEMA was determined using a DS 7000 oscillating U-tube Density Meter (Küss) to be 1.119 g / cm 3<. A polymerization shrinkage of only 7.4 vol% was determined for the monomer. Example 2 Synthesis of urethane dimethacrylate telechelates according to the invention General procedure for the reaction of diols with diisocyanates and HEMA endcapping (1:2:2)

[0131] A mixture of 1 equivalent of diol, 2 equivalents of isophorone diisocyanate (IPDI), and 700 ppm (based on IPDI) of Metatin 712 was heated to 40 °C. The diol dissolved completely, and the mixture heated to approximately 110 °C. After the exothermic reaction subsided, the mixture was stirred for 1 h at a bath temperature of 80 °C before 2 equivalents of 2-hydroxyethyl methacrylate (HEMA, stabilized with 30 ppm (based on 100% product) BHT) were added dropwise. After the exothermic reaction subsided, the mixture was stirred for a further 10 min at 90 °C. The completeness of the reaction was verified by IR and NMR spectroscopy. The adducts were obtained as colorless, very highly viscous to brittle resins. A. 1,10-decanediol-IPDI-HEMA adduct (1:2:2), isomer mixture (DMA-Telechel-1, molecular weight: 879.15 g / mol)

[0132]

[0133] 1,10-decanediol was used as the diol.

[0134] 1< H NMR (400 MHz, CDCl 3 ): δ (ppm) = 0.85-0.97, 1.01-1.06, 1.19-1.38 and 1.59-1.75 [4 m, 46H, (CH 2 ) 8 , CH 2 , cycl , CH 3 , cycl ), 2.03 (s, 6H, CH 3 , methacrylic), 2.81-2.98 and 3.20-3.33 (2 m, 4H, NCH 2 ), 3.65-3.88 [m, 2H, NCH], 3.98-4.11 (m, 4H, OC H 2 (CH 2 ) 8 ), 4.26-4.40 (m, 8H, O(CH 2 ) 2 O), 4.57-4.94 (m, 4H, NH), 5.60 and 6.14 (2 s, 2H each, =CH 2 ).

[0135] IR (diamond ATR): v (cm -1< ) ​​= 3341 (br, NH), 2927 and 2856 (m, CH), 1695 (vs, C=O), 1638 (m, C=C), 1526 (s, NH), 1456 (m, CH 2 , CH 3 ), 1366 (m, CH 3 ), 1236 (CN), 1167 and 1039 (s, m, COC), 942 (m, =CH), 774 [m, (CH 2 ) 8 ]. B. Bisphenol A-IPDI-HEMA adduct (1:2:2), isomer mixture (DMA-Telechel-2, molecular weight: 1049.31 g / mol)

[0136]

[0137] A bisphenol A derivative with pendant iso-propoxy groups was used as the diol according to the following formula:

[0138] 1< H NMR (400 MHz, CDCl 3 ): δ (ppm) = 0,86-1,06, 1,18-1,21, 1,29-1,40 und 1,62-1,75 [4 m, 42H, CH 2, cycl. , CH 3 ), 1,95 (s, 6H, CH 3, methacryl ), 2,87-2,99 und 3,19-3,36 (2 m, 4H, NCH 2 ), 3,67-3,88 [m, 2H, NCH], 3,91-4,03 und 4,09-4,22 (2 m, 4H, OC H 2 CH), 4,26-4,40 und 4,50-5,18 (2 m, 14H, O(CH 2 ) 2 O, OCH 2 C H , NH), 5,59 und 6,15 (2 s, je 2H, =CH 2 ), 6,80 und 7,12 (2 d, je 4H, =CH).

[0139] IR (diamond ATR): v (cm -1< ) = 3341 (br, NH), 2955 und 2860 (m, C-H), 1705 (vs, C=O), 1640 (w, C=C), 1608 (w, Aromat), 1507 (s, NH), 1456 (m, CH 2 , CH 3 ), 1385 (m, CH 3 ), 1231 (C-N), 1155 und 1043 (s, m, COC), 941 (m, =CH), 829 (m, =CH aromat ). Example 3 Synthesis of PCL(1600)-b-PDMS(3200)-b-PCL(1600) block copolymer (PO-277) 1st stage: Tetramethylammonium 3-aminopropyldimethylsilanoate

[0140] Under a protective gas atmosphere, a mixture of 1,3-bis(3-aminopropyl)tetramethyldisiloxane (2.49 g, 10.0 mmol) and tetramethylammonium hydroxide pentahydrate (3.62 g, 20 mmol) in tetrahydrofuran (THF; 10 ml) was heated at reflux for 3 h. The solvent was distilled off, and the residue was warmed to 50 °C under medium vacuum. The yellowish residue was recrystallized from THF (20 ml). This yielded 3.17 g (15.4 mmol; 77%) of a white solid.

[0141] 1< H-NMR (CDCl 3 , 400 MHz): δ = 3.16 (s, 12H; N +< -CH 3 ), 2.37(t, 2H; J = 7.1 Hz; N-CH 2 ), 1.28 (m, 2H; CH 2 ), 0.14 (m, 2H; Si-CH 2 ), -0.33 (s, 6H; Si-CH3). 2nd stage: Polydimethylsiloxane-αω-dipropyl-3-amine: PDMS(3200)

[0142] A mixture of 1,3-bis(3-aminopropyl)tetramethyldisiloxane (4.98 g, 20.0 mmol) and octamethylcyclotetrasiloxane (12.00 g, 40 mmol) was heated to 80 °C under a protective gas atmosphere. Tetramethylammonium 3-aminopropyldimethylsilanoate (20 mg) was added, and stirring was continued at 80 °C. After 30 min, argon-saturated octamethylcyclotetrasiloxane (56.00 g, 0.192 mol) was slowly added dropwise. The reaction mixture was stirred for a further 18 h at 80 °C and then heated to 150 °C for 30 min to decompose the catalyst. Volatile components were then removed under medium vacuum. 65.30 g (88%) of a colorless oil were obtained.

[0143] 1< H-NMR (CDCl 3 , 400 MHz): δ =2.64 (t, 4H; J = 7.0 Hz; N-CH 2 ), 1.43 (m, 4H; CH 2 ), 0.51 (m, 4H; Si-CH 2 ), 0.05 (s, 250H; Si-CH 3 ). 3rd stage: PCL(1600)-b-PDMS(3200)-b-PCL(1600) block copolymer

[0144] A mixture of PDMS(3200) (20.00 g) and ε-caprolactone (20.40 g) was heated to 80 °C. After 1 h, tin bis(2-ethylhexanoate) (10 mg) was added, and the bath temperature was gradually increased to 130 °C within 0 min. The now clear reaction mixture was stirred at 130 °C for a further 5 h. Volatile components were then distilled off under a fine vacuum. 39.50 g (98%) of the block copolymer was obtained as a waxy, slightly yellowish solid.

[0145] 1< H-NMR (CDCl 3 , 400 MHz): δ = 3.99 (t, 55H; J = 6.8 Hz; O-CH 2 ), 3.57 (t, 4H; J = 6.8 Hz; HO-CH 2 ), 3.15 (q, 4H; J = 6.8 Hz; N-CH 2 ), 2.24 (t, 55H; J = 7.5 Hz; C(O)-CH2 ), 2.10 (t, 4H; J = 7.5 Hz; N-CH2 ), 1.58 (m, 118H; CH2 ), 1.32 (m, 59H; CH2 ), 0.46 (m, 4H; Si-CH2 ), 0.02 (s, 250H; Si-CH 3 ). Example 4 Synthesis of PMMA(1200)-b-PDMS(3200)-b-PMMA(1200) block copolymer 1st stage: α, ω-(2-bromoisobutyrylaminopropyl)-poly(dimethylsiloxane)

[0146] α-Bromoisobutyric bromide (1.44 g; 6.24 mmol) was added dropwise to a solution of PDMS(3200) (6.66 g; 2.08 mmol) and triethylamine (0.84 g; 8.44 mmol) dissolved in THF (100 mL) at 0 °C. The reaction mixture was stirred for 2 h with ice cooling and for 18 h at ambient temperature. The suspension was filtered, and the filtrate was concentrated on a rotary evaporator. The colorless oil was dissolved in dichloromethane (100 mL) and washed with saturated aqueous Na 2 CO 3 solution (2 x 50 mL), hydrochloric acid (0.2 N, 2 x 50 mL), and saturated aqueous NaCl solution (100 mL), dried over anhydrous sodium sulfate, filtered, and concentrated on a rotary evaporator. Volatile components were removed under medium vacuum, yielding 6.32 g (1.81 mmol; 87%) of a slightly yellowish liquid.

[0147] 1< H-NMR (CDCl 3 , 400 MHz): δ = 3.22 (m, 4H; N-CH 2 ), 1.92 (s, 12H; C-CH 3 ), 1.54 (m, 4H; CH 2 ), 0.53 (m, 4H; Si-CH 2 ), 0.05 (s, 258H; Si-CH 3 ). 2nd stage: PMMA(1200)-b-PDMS(3200)-b-PMMA(1200) block copolymer

[0148] Under inert gas conditions, α,ω-(2-bromoisobutyrylaminopropyl)-poly(dimethylsiloxane) (6.22 g; 1.78 mmol), copper(I) chloride (0.35 g; 3.56 mmol), and N,N,N',N",N"-pentamethyldiethylenetriamine (0.62 g; 3.56 mmol) were treated with toluene (50 ml), and the solution was degassed. Methyl methacrylate (7.78 g; 77.7 mmol) was added. The solution was stirred at ambient temperature for 30 min and then heated to 90 °C for 20 h. After cooling, the solution was filtered through neutral alumina. The filtrate was concentrated on a rotary evaporator. The residue was dissolved in dichloromethane and filtered through silica gel. The filtrate was concentrated on a rotary evaporator, and the residue was dried under medium vacuum. 8.77 g (1.49 mmol; 84%) of the block copolymer was obtained as a yellowish solid.

[0149] 1< H-NMR (CDCl 3 , 400 MHz): δ = 3.53 (s, 72H; O-CH 3 ), 3.28-3.03 (m, 4H; N-CH 2 ), 2.20-1.12 (m, 64H; C-CH 3 , CH 2 ), 1.13-0.63 (m 72H, CH 3 ), 0.55-0.40 (m, 4H; SiCH 2 ), 0.0 (s, 252H, Si-CH 3 ). Example 5 Synthesis of PCL(2500)-b-PDMS(3200)-b-PCL(2500) block copolymer

[0150] A mixture of PDMS(3200) (20.00 g) and ε-caprolactone (30.60 g) was heated to 80 °C. After 1 h, tin bis(2-ethylhexanoate) (10 mg) was added, and the bath temperature was gradually increased to 130 °C over 30 min. The now clear reaction mixture was stirred at 130 °C for a further 5 h. Volatile components were then distilled off under medium vacuum. 49.00 g (97%) of a waxy, slightly yellowish solid were obtained.

[0151] 1< H-NMR (CDCl 3 , 400 MHz): δ = 3.99 (t, 86H; J = 6.8 Hz; O-CH 2 ), 3.57 (t, 4H; J = 6.8 Hz; HO-CH 2 ), 3.15 (q, 4H; J = 6.8 Hz; N-CH 2 ), 2.24 (t, 86H; J = 7.5 Hz; C(O)-CH2 ), 2.10 (t, 4H; J = 7.5 Hz; N-CH2 ), 1.60-1.54 (m, 180H; CH2 ), 1.34-1.29 (m, 90H; CH2 ), 0.51-0.40 (m, 4H; Si-CH2 ), 0.02 (s, 250H; Si-CH 3 ). Example 6 Synthesis of PCL(3200)-b-PDMS(3200)-b-PCL(3200) block copolymer

[0152] A mixture of PDMS(3200) (15.00 g) and ε-caprolactone (30.60 g) was heated to 80 °C. After 1 h, tin bis(2-ethylhexanoate) (10 mg) was added, and the bath temperature was gradually increased to 130 °C over 30 min. The now clear reaction mixture was stirred at 130 °C for a further 5 h. Volatile components were then distilled off under medium vacuum. 44.20 g (97%) of a waxy, slightly yellowish solid was obtained.

[0153] 1< H-NMR (CDCl 3 , 400 MHz): δ = 3,99 (t, 106H; J = 6,8 Hz; O-CH 2 ), 3,57 (t, 4H; J = 6.8 Hz; HO-CH 2 ), 3,15 (q, 4H; J = 6,8 Hz; N-CH 2 ), 2,24 (t, 106H; J = 7,5 Hz; C(O)-CH 2 ), 2,10 (t, 4H; J = 7,5 Hz; N-CH 2 ), 1,60-1,54 (m, 220H; CH 2 ), 1,34-1,29 (m, 110H; CH 2 ), 0,51-0,40 (m, 4H; Si-CH 2 ), 0,02 (s, 250H; Si-CH 3 ). Example 7 Production of polymerization and SL resins

[0154] The components listed in Table 1 were mixed together homogeneously in the specified amounts. To this end, all solid components (block copolymer or core-shell particles, photoinitiator) were dissolved in the monomers in a planetary mixer or speed mixer with stirring, if necessary while heating to 50 °C. The urethane dimethacrylate chelates were then added and stirring continued until a homogeneous mixture was achieved. The block copolymers could be easily incorporated into the mixtures. To incorporate core-shell particles, the mixture was additionally homogenized using a rotor-stator mixer (Ultra-Turrax T-25) at a speed of 3000 rpm for 30 minutes. The mixtures were then deaerated in the planetary mixer.

[0155] Test specimens were produced using formulations No. 5 and No. 6 in a bottom-up process using a stereolithography printer (PrograPrint PR5, Ivoclar Vivadent AG, Schaan, Liechtenstein). The printer exposed the samples using DLP technology at a wavelength of 388 nm, an output of 10 mW / cm2, and a pixel size of 50 µm in a layer-by-layer buildup. The layer thickness was 100 µm in each case. Adhering residual resin was removed with isopropanol. For this purpose, the test specimens, together with the build platform (PrograPrint Stage), were cleaned twice with a PrograPrint Clean device (Ivoclar Vivadent AG, Schaan, Liechtenstein) in fresh isopropanol while stirring (first bath 10 min, second bath 5 min) and immediately afterwards blown dry with compressed air. The test specimens were then post-cured by irradiating them with light at a wavelength of 405 nm for 90 seconds. This was done using a PrograPrint Cure device (from the manufacturer).Ivoclar Vivadent AG, Schaan, Liechtenstein; Software: ProArt Print Splint, 2020). The test specimens were then removed from the build platform.

[0156] Test specimens were prepared in metal molds using the remaining compositions from Table 1, which were irradiated on both sides with a dental light source (PrograPrint Cure, Ivoclar Vivadent AG, Schaan, Liechtenstein; software: ProArt Print Splint, year: 2020) and thus cured.

[0157] Further processing and storage of the test specimens was carried out in accordance with the relevant specifications of the following regulations. The flexural strength (BF) and flexural elastic modulus (BM) were determined according to ISO standard ISO-4049 (Dentistry - Polymer-based filling, restorative and luting materials). For this purpose, the test specimens were previously stored either in a dry state at room temperature for 24 hours or in water at 37 °C for 24 hours. In addition, the flexural strength and flexural modulus were measured according to ISO standard 20795-1:2013 (Dentistry - Plastics - Part 1: Denture plastics). The test specimens were then stored in deionized water at 37 °C for 50 hours prior to measurement, and the measurement was then carried out in a thermostatically controlled underwater tank at 37 °C. The fracture toughness K max and the fracture energy FW were determined according to ISO 20795-1:2013. The results of the measurements are shown in Table 2.

[0158] Formulations No. 1 and No. 10 are reference examples that contain neither core-shell polymer nor block copolymer. While these reference examples exhibit good flexural strength and flexural modulus, the fracture toughness and work of fracture values ​​are poor and unsuitable for stereolithography applications. Examples No. 3, No. 4, and No. 14 each contain core-shell polymer particles. The addition of the particles results in an improvement in fracture toughness (K max and work of fracture FW) in all cases.

[0159] In Example 14, Formulation 10 was mixed with 5 wt.% core-shell particles. The addition of the core-shell polymer not only improves fracture toughness but also significantly reduces transparency. In Examples 12, 13, and 15, 5 wt.% of a block copolymer was added as an impact modifier instead of the core-shell particles. Table 2 shows that in all cases, the block copolymers provide a significantly greater improvement in fracture toughness than the core-shell particles, but result in only a comparatively slight reduction in transparency. Example 11 shows that the addition of 3 wt.% of a block copolymer is sufficient to achieve a similar improvement in fracture toughness as 5 wt.% core-shell particles.

[0160] A comparison of Examples 2 and 3 shows that the addition of 3 wt.% block copolymer results in approximately the same improvement in fracture toughness as 5 wt.% core-shell particles. Example 2 is characterized by higher transparency compared to Example 3, confirming that the use of block copolymers enables the production of materials with high fracture toughness and transparency.

[0161] A comparison of examples No. 3 and No. 4 shows that although a further improvement in fracture toughness is possible by increasing the amount of core-shell particles from 5 to 10 wt.%, this is associated with an increasing deterioration in transparency. Table 2: Properties of the hardened materials Viscosity 1)< Flexural strength or modulus 5)< dry ISO4049 Flexural strength or modulus 6)< in water ISO4049 Flexural strength or modulus 7)< ISO20795-2 Fracture toughness ISO2795-2 Glass transition temperature 3)< TG Network density 4)< vc Transparency 2)< Batch η [Pa·s] BF [MPa] BM [MPa] BF [MPa] BM [MPa] BF [MPa] BM [MPa] K max [MPa·m 1 / 2< ] FW [J / m 2< ] [°C] [mol / m 3 ] [%] Nr. 1*) 1,2 128,6 3157 108,3 2642 86,7 2499 0,897 118 85,8 1365 88,6 Nr. 2 1,5 89,4 2430 78,7 2208 71,4 2090 1,703 349 89,3 1660 81,0 Nr. 3*) 2,0 80,9 2307 86,5 2382 77,6 2077 1,732 370 nb nb 76,1 Nr. 4*) nb 106,5 2740 96,1 2451 56,2 1697 2,060 657 nb nb 65,0 Nr. 5 nb nb nb nb nb 59,1 1547 1,607 476 nb nb nb Nr. 6 nb nb nb nb nb 41,9 1036 1,604 616 nb nb nb Nr. 7 3,3 101,5 2729 87,9 2605 85,9 2553 1,610 287 nb nb nb Nr. 8 3,5 88,3 2424 86,9 2370 74,5 2148 2,082 577 nb nb nb Nr. 9 0,9 97,1 2753 88,0 2591 77,8 2273 1,481 255 nb nb nb Nr. 10*) 4,2 117,2 3325 113,0 3103 85,2 3115 0,859 93 98,4 1060 90,9 Nr. 11 4,4 100,5 3110 96,3 2950 88,5 2726 1,801 326 nb nb 85,0 Nr. 12 4,2 112,9 3221 104,7 2919 88,6 2507 2,068 489 nb nb 88,2 Nr. 13 4,8 109,1 3230 104,3 2855 88,5 2624 2,146 546 nb nb 88,7 Nr. 14*) 3,7 105,9 3105 103,6 3170 65,1 2990 1,680 296 nb nb 59,5 Nr. 15 4,6 96,4 2858 96,3 2840 69,2 2192 2,010 613 nb nb 83,0 Nr. 16 4,1 107,1 3382 75,7 2381 62,8 1993 1,933 643 nb nb 87,5 *) Comparison example nbnot determined 1)< Rotational viscosity, determined with an Anton Paar viscometer model MCR 302 with CP25-2 cone-plate measuring device and a measuring gap of 53 µm in rotation at a shear rate of 100 / s at 25°C 2)< determined with a Konika-Minolta spectrophotometer model CM-5 on 1 mm thick, highly polished test specimens in transmission (D65) 3)< Storage and loss modulus of a test specimen (25 x 5 x 1 mm, clamped lengthwise) were determined between 25°C and 250°C with an Anton Paar rheometer model MCR302 (frequency 1 Hz, deformation 0.05%, heating rate 2K / min); TG corresponds to the maximum of the loss factor tan δ (ratio of loss modulus to storage modulus) 4)< the network density was calculated according to the formula vc = G' / (RT), G' is the storage modulus at the temperature TG + 50 K; R is the general gas constant; T is the temperature at TG + 50 K 5)< Flexural strength (BF) and flexural modulus (BM) measured according to ISO4049 after dry storage for 24 h at . RT 6)< Flexural strength (BF) and flexural modulus (BM) measured according to ISO4049 after storage for 24 h at 37°C in water 7)< Flexural strength (BF) and flexural modulus (BM) measured according to ISO20795-2

Claims

1. Radically polymerizable dental material, which comprises at least one ABA or AB block copolymer (d), at least one monofunctional, radically polymerizable monomer (a) and at least one radically polymerizable urethane di(meth)acrylate telechel (b), characterized in that the urethane di(meth)acrylate telechel (b) has a number-average molar mass of from 750 to 2000 g / mol and corresponds to the general formula (II), in which the variables have the following meanings: R1, R2 independently of each other in each case H or methyl, R3, R4 independently of each other in each case H or methyl, x, y independently of each other in each case an integer from 1 to 11, n 1, 2 or 3, Z DA a structural element, which is derived from a diol HO-DA-OH by cleaving the hydrogen atoms from the hydroxyl groups, wherein the diol HO-DA-OH is selected from the following compounds: ethoxylated or propoxylated bisphenol A, o-diphenyl or p-diphenyl with 2 to 6 ethoxy or propoxy groups, C2-C18 alkanediols, which can contain 1 to 4 O or S atoms in the carbon chain, cyclic or polycyclic aliphatic diols.

2. Radically polymerizable dental material according to claim 1, which comprises (a) 30 to 70 wt.-%, preferably 30 to 61 wt.-% and particularly preferably 40 to 60 wt.-% of at least one aromatic, bicyclic or tricyclic mono(meth)acrylate, (b) 20 to 60 wt.-%, preferably 30 to 55 wt.-% and particularly preferably 33 to 55 wt.-% of at least one urethane di(meth)acrylate telechel with a number-average molar mass of from 750 to 2000 g / mol, (c) 0 to 30 wt.-%, preferably 0 to 20 wt.-% and particularly preferably 0 wt.-% of di(meth)acrylate monomer(s), (d) 1 to 12 wt.-%, preferably 2 to 12 wt.-% and particularly preferably 2 to 10 wt.-% of at least one ABA and / or AB block copolymer, wherein the A block or blocks are homogeneously miscible with the mixture of components (a) to (c) and the B block is not homogeneously miscible with the mixture of components (a) to (c), and (e) 0.1 to 5.0 wt.-%, preferably 0.2 to 4.0 wt.-% and particularly preferably 0.3 to 3.0 wt.-% of at least one initiator for the radical polymerization, in each case relative to the total mass of the material.

3. Dental material according to claim 1, which comprises as monomer (a) at least one aromatic, bicyclic or tricyclic monomethacrylate of Formula (I) in which the variables have the following meanings: A an aromatic group with 6 to 15 carbon atoms or a bicyclic or tricyclic aliphatic group with 7 to 10 carbon atoms, wherein A can be unsubstituted or substituted by one or more C1-C5 alkyl groups, C1-C5 alkoxy groups and / or chlorine atoms; R hydrogen or methyl; X1, X2 are each independently absent or an ether, ester or urethane group, wherein X1 is absent if Y1 is absent and wherein X2 is absent if Y2 is absent; Y1, Y2 are each independently absent or a branched or preferably linear aliphatic hydrocarbon radical with 1 to 10 carbon atoms, which can be interrupted by 1 to 3 oxygen atoms.

4. Dental material according to claim 3, which comprises as component (a) 2-phenoxyethyl (meth)acrylate, 2-(o-biphenyloxy)ethyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, phenethyl (meth)acrylate, 2-[(benzyloxycarbonyl)-amino]-ethyl (meth)acrylate, 2-[(benzylcarbamoyl)-oxy]-ethyl (meth)acrylate, 1-phenoxypropan-2-yl (meth)acrylate and 2-(p-cumylphenoxy)-ethyl (meth)acrylate, 2-(benzyloxy)ethyl (meth)acrylate, 3-phenoxybenzyl (meth)acrylate, phenoxypropyl (meth)acrylate, 2-benzyloxyethyl (meth)acrylate, 2-benzoyloxyethyl (meth)acrylate, 2-(meth)acryloyloxybenzoic acid methyl ester, tricyclodecane (meth)acrylate, tricyclodecane methyl (meth)acrylate, 2-(p-cumylphenoxy)ethyl (meth)acrylate, 4,7,7-trimethylbicyclo[2.2.1]heptanyl (meth)acrylate, octahydro-1H-4,7-methanoinden-5-yl (meth)acrylate or a mixture thereof.

5. Dental material according to any one of claims 1 to 4, which comprises as component (b) a telechel according to the general formula (II), in which the variables have the following meanings: R1, R2 each methyl, R3, R4 each methyl , x, y independently of each other, each an integer from 1 to 5, n 1, Z DA a structural element, which is derived from a diol HO-DA-OH by cleaving the hydrogen atoms from the hydroxyl groups, wherein the diol HO-DA-OH is selected from the following compounds: ethoxylated or propoxylated bisphenol A with 2, 3 or 4 ethoxy or propoxy groups, hexane-1,6-diol, octane-1,8-diol, nonane-1,9-diol, decane-1,10-diol, undecanediol or dodecane-1,12-diol, tetra- or pentaethylene glycol, cyclohexanediol, norbornanediol, tri-cyclodecanediol and tricyclodecanedimethanol (octahydro-4,7-methano-1H-indenedimethanol).

6. Dental material according to one of claims 1 to 5, which comprises as component (d) at least one ABA and / or AB block copolymer, in which the A block is an oligomer which is made up of one or more of the following monomers: cyclic, aliphatic esters or ethers, arylene oxide, alkylene oxide, radically polymerizable monomers, for example α,β-unsaturated acids and α,β-unsaturated acid esters; and the B block is a polysiloxane oligomer and / or a polyvinyl oligomer and / or a polyalkene oligomer and / or a polydiene oligomer.

7. Dental material according to claim 6, which comprises as component (d) at least one ABA and / or AB block copolymer, in which the A block is an oligomeric polycaprolactone (PCL), poly(2,6-dimethyl-1,4-phenylene oxide), poly(ethylene oxide), poly(propylene oxide) or poly(meth)acrylate building block and the B block is an oligomeric poly(dimethylsiloxane) (PDMS), poly(isoprene), poly(vinyl acetate), poly(isobutene), cis-poly(butadiene) or poly(ethylene) building block.

8. Dental material according to claim 7, which comprises as component (d) at least one ABA triblock copolymer of the PCL-b-PDMS-b-PCL and / or PMMA-b-PDMS-b-PMMA type with a molar ratio of A:B of from 0.1 to 5 and with a molar mass of from 3 to 25 kDa, preferably 4 to 20 kDa and particularly preferably 5 to 10 kDa.

9. Dental material according to one of claims 1 to 8, which comprises as component (e) at least one photoinitiator, which is preferably selected from benzophenone, benzoin or a derivative thereof, an α-diketone or a derivative thereof, such as 9,10-phenanthrenequinone, 1-phenyl-propane-1,2-dione, diacetyl or 4,4'-dichlorobenzil, camphorquinone (CQ), 2,2-dimethoxy-2-phenylacetophenone or an α-diketone in combination with an amine as reducing agent, such as e.g. 4-(dimethylamino)-benzoic acid ester (EDMAB), N,N-dimethylaminoethyl methacrylate, N,N-dimethyl-sym.-xylidine or triethanolamine, monoacyltrialkyl-, diacyldialkyl-, tetraacylgermanium, a tetraacylstannane, benzoyltrimethylgermanium, dibenzoyldiethylgermanium, bis(4-methoxybenzoyl)diethylgermanium, tetrakis(2-methylbenzoyl)germane or tetrakis(mesitoyl)stannane or a mixture thereof, a Norrish type I photoinitiator, such as acetophenones, e.g. 2,2-diethoxy-1-phenylethanone, benzoin ethers e.g. Irgacure 651 (benzil dimethyl ketal), hydroxyalkylphenylacetophenones, e.g. Irgacure 184 (1-hydroxycyclohexyl phenyl ketone), an acyl- or bisacylphosphine oxide, e.g. Irgacure TPO (2,4,6-trimethylbenzoyldiphenylphosphine oxide) or Irgacure 819 (bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide), 2-benzyl-2-(dimethylamino)-4'-morpholinobutyrophenone (Irgacure 369) and / or 1-butanone-2-(dimethylamino)-2-(4-methylphenyl)methyl-1-4-(4-morpholinyl)phenyl (Irgacure 379).

10. Dental material according to one of claims 1 to 9, with the following composition: (a) 30 to 70 wt.-%, preferably 30 to 61 wt.-%, particularly preferably 40 to 60 wt.-% of at least one aromatic, bicyclic or tricyclic mono(meth)acrylate, (b) 20 to 60 wt.-%, preferably 30 to 55 wt.-% and particularly preferably 33 to 55 wt.-% of at least one urethane di(meth)acrylate telechel with a number-average molar mass of from 750 to 2000 g / mol, (c) 0 to 30 wt.-%, preferably 0 to 20 wt.-% and particularly preferably 0 wt.-% of di(meth)acrylate monomer(s), (d) 1 to 12 wt.-%, preferably 2 to 12 wt.-%, particularly preferably 2 to 10 wt.-% of at least one ABA or AB block copolymer, (e) 0.1 to 5.0 wt.-%, preferably 0.2 to 4.0 wt.-% and particularly preferably 0.3 to 3.0 wt.-% of at least one initiator for the radical polymerization, (f) 0 to 15 wt.-%, preferably 0 to 5 wt.-% and particularly preferably 0 wt.-% of core-shell polymer particles, (g) 0 to 20 wt.-%, preferably 0 to 15 wt.-% and particularly preferably 0 to 10 wt.-% of filler, (h) 0 to 1.0 wt.-%, preferably 0 to 0.7 and particularly preferably 0 to 0.5 wt.-% of UV absorber, (i) 0 to 0.5 wt.-%, preferably 0 to 0.1 wt.-% and particularly preferably 0 to 0.05 wt.-% of optical brightener and (j) 0 to 15 wt.-%, preferably 0 to 10 wt.-% and particularly preferably 0.2 to 5 wt.-% of further additives, in each case relative to the total mass of the material.

11. Dental material according to claim 10, which comprises (a) 40 to 61 wt.-% of 2-phenoxyethyl (meth)acrylate, 2-(o-biphenyloxy)ethyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 2-[(benzyloxycarbonyl)amino]ethyl (meth)acrylate, 1-phenoxypropan-2-yl (meth)acrylate, 2-(benzyloxy)-ethyl (meth)acrylate, 2-(methacryloyloxy)ethyl (meth)acrylate, 3-phenoxybenzyl (meth)acrylate, phenoxypropyl (meth)acrylate, 2-benzyloxyethyl (meth)acrylate, 2-benzoyloxyethyl (meth)acrylate, 2-(meth)acryloyloxybenzoic acid methyl ester, 2-phenylethyl (meth)acrylate, tricyclodecane (meth)acrylate, tricyclodecane methyl (meth)acrylate and / or 2-(p-cumylphenoxy)ethyl methacrylate, (b) 33 to 55 wt.-% of at least one urethane di(meth)acrylate telechel with a number-average molar mass of 750-2000 g / mol and with at least 4 urethane groups, prepared by reacting 1 mol ethoxylated or propoxylated bisphenol A, decanediol or dodecanediol with 2 mol isophorone diisocyanate (IPDI) and then reacting with 2 mol 2-hydroxyethyl methacrylate (HEMA) or hydroxypropyl methacrylate (HPMA), (c) 0 wt.-% further di(meth)acrylate monomers, (d) 2 to 10 wt.-% of at least one ABA or AB block copolymer, wherein the A block is made up of oligomeric polycaprolactone, poly(2,6-dimethyl-1,4-phenylene oxide), poly(ethylene oxide), poly(propylene oxide) or poly(meth)acrylate building blocks and the B block is made up of poly(dimethylsiloxane), poly(isoprene), poly(vinyl acetate), poly(isobutene), cis-poly(butadiene) or poly(ethylene) building blocks, (e) 0% of core-shell polymers, (f) 0.1 to 5.0 wt.-% of at least one photoinitiator and (g) 0.2 to 5 wt.-% of one or more further additives, in each case relative to the total mass of the material.

12. Process for the production of dental shaped parts in which (i) a virtual image of the tooth situation is created by direct or indirect digitization of the tooth to be restored or of the teeth to be restored on a computer, (ii) then a model of the dental restoration or prosthesis is constructed on the computer on the basis of this image, (iii) a dental material in accordance with one of claims 1 to 11 is then polymerized in layers by selective light irradiation in order to form the dental restoration and (iv) the workpiece is then cleaned, optionally by treatment with a solvent, and (v) the workpiece is then optionally further cured by irradiating with light and / or by heating to a temperature above 50°C.

13. Use of a material in accordance with one of claims 1 to 11 as dental material or for the production or repair of dental shaped parts.