Curable composition for optical lens by additive manufacturing

Abstract

The present invention relates to a curable composition for additive manufacturing processes, especially vat technologies, comprising at least a polymerizable composition and a photoinitiator for the manufacture of optical articles, especially ophthalmic articles. The present invention also relates to a method of manufacturing a three-dimensional (3D) optical article from the curable composition.

Description

[0001] CURABLE COMPOSITION FOR OPTICAL LENS BY ADDITIVE MANUFACTURING

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to a curable composition for additive manufacturing processes, especially vat technologies, comprising at least a polymerizable composition and a photoinitiator for the manufacture of optical articles, especially ophthalmic articles. The present invention also relates to a method of manufacturing a three-dimensional (3D) optical article from the curable composition.

[0004] BACKGROUND OF THE INVENTION

[0005] It is known to use an additive manufacturing technology, such as vat photopolymerization additive manufacturing, to manufacture an optical article such as a lens.

[0006] Vat photopolymerization additive manufacturing, also called vat technology or vat- photopolymerization three-dimensional (3D) printing, is generally a three-dimensional (3D) printing technology where a light source, typically UV, cures photopolymer composition (or resin) in a vat to form progressively, continuously or layer-by-layer an optical article. A build platform is positioned within the vat and operates in either a "top-down" approach, descending into the composition, or a "bottom-up" method, moving from the vat bottom up. Examples of vat technologies include frontal photopolymerization (FPP), continuous liquid interface production (CLIP), daylight polymer printing (DPP), stereolithography (SLA), and digital light processing (DLP).

[0007] Typically, in a continuous printing process, such as CLIP, the optical article is continuously formed from the composition. The structure of the article is obtained by inhibiting the polymerization of the composition in some areas of the vat using oxygen. In a layer-by- layer printing process, such as SLA, each layer is selectively cured by exposing it to the light, which solidifies the composition where the light hits, and the process is generally repeated layer by layer until the desired article is created.

[0008] For example, according to digital light processing stereolithography (DLP-SLA), an image of a slice of the part of the optical article to print is projected on a liquid composition vat surface in order to print a layer. After each layer is formed, the part is moved vertically to print a new layer. The part can be moved above or inside the vat. The printing includes a support for the part. At the end of the process, the part of the optical article is removed from the vat. Generally, the optical article is then washed to remove residual liquid composition. In frontal photopolymerization processes, the photoinitiated polymerization reaction typically propagates as a front through the liquid composition, converting it into a solid polymer. The optical article is thus progressively formed.

[0009] To be suitable for vat photopolymerization additive manufacturing, the composition must have certain physical properties. For example, the composition must have a viscosity around 1000 cP and a high stability during the printing.

[0010] Regardless of the manufacturing method, the optical article must also meet certain optical and physical criteria such as a high stability over time, a relative light transmission factor in the visible spectrum (Tv) higher or equal to 80 %, an Abbe number greater than 38, for example, a Yellowness Index less than 1,5 for a thickness of 2 mm, a glass transition temperature (Tg) equal to or less than 100°C, a storage modulus higher than or equal to 1 ,5 GPa at 25°C or a low shrinkage. The optical article must also meet certain chemical criteria such as a low water uptake (over 24h, less than 0.5 weight% relative to the total weight of the optical article) or a good resistance to solvent such as methanol.

[0011] Thus, there is a need in the art to develop a composition with good physical properties compatible with vat technology and resulting in a polymer with mechanical, chemical and / or optical properties suitable for optical products.

[0012] INVENTION SUMMARY

[0013] A first object of the present invention is a curable composition comprising at least

[0014] - one photoinitiator and

[0015] - a polymerizable composition containing at least a mixture of:

[0016] - 20 to 80 weight% of a first polymerizable component,

[0017] - 20 to 80 weight% of a second polymerizable component, with the weight percentage (weight%) based on the total weight of the polymerizable composition and, wherein,

[0018] • The first polymerizable component is an aliphatic urethane (meth)acrylate oligomer,

[0019] • The second polymerizable component is of formula (I): Wherein

[0020] Ri is a non-aromatic carbocycle or non-aromatic heterocycle wherein the cycle comprising 3 to 20 atoms and is optionally substituted by at least one linear or branched saturated alkyl having 1 to 10 carbon atoms and / or at least one acryloxy and / or one methacryloxy group;

[0021] R2 and R3, identical or different, are independently an alkylene, an alkoxylene, an alkyleneoxy, a poly(alkylene) or a poly(alkoxylene) or a poly(alkyleneoxy), wherein the alkylene and the alkoxylene and the alkylenoxy are linear or branched, saturated and having 1 to 10 carbon atoms and wherein the alkylene, the alkoxylene, the alkylenoxy, the poly(alkylene), the poly(alkoxylene) or the poly(alkylenoxy) is optionally substituted, for example by at least one hydroxyl, and / or one acryloxy and / or one methacryloxy group;

[0022] R4, Rs, Re, R9, R10 and Rn, identical or different, are independently hydrogen or a linear or branched saturated alkyl having 1 to 4 carbon atoms, preferably independently a hydrogen or -CH3; m and p, identical or different, are independently 0 or 1 ; and wherein the polymerizable composition further comprises a (meth) acrylate monomer of formula (II):

[0023] Wherein

[0024] R12 is a non-aromatic carbocycle or non-aromatic heterocycle wherein the cycle comprising 3 to 20 atoms and is optionally substituted by at least one linear or branched saturated alkyl having 1 to 10 carbon atoms;

[0025] R13 is an alkylene, an alkoxylene, an alkyleneoxy, a poly(alkylene) or a poly(alkoxylene) or a poly(alkyleneoxy), wherein the alkylene and the alkoxylene and the alkylenoxy are linear or branched, saturated and having 1 to 10 carbon atoms and wherein the alkylene, the alkoxylene, the alkylenoxy, the poly(alkylene), the poly(alkoxylene) or the poly(alkylenoxy) is optionally substituted, for example by at least one hydroxyl, and / or one acryloxy and / or one methacryloxy group;

[0026] R14, R15 and R16, identical or different, are independently hydrogen or a linear or branched saturated alkyl having 1 to 4 carbon atoms, preferably independently a hydrogen or -CHs; n is 0 or 1 , wherein when n=0 the acrylate group is directly bonded to R12 and when n=1 the acrylate group is bonded to R13.

[0027] A second object of the present invention is an optical material obtained by the curing of the said curable composition.

[0028] A third object of the present invention is a method for the manufacturing of an optical element, said method comprising the photopolymerization of the said curable composition. In particular, the present invention is directed to the use of the said curable composition for the manufacturing of a 3-Dimensional (3D) printed element, preferably an optical element.

[0029] A fourth object of the present invention is an optical element obtained by method comprising the photopolymerization of the said curable composition.

[0030] The invention is also directed to an ophthalmic lens comprising at least one said optical element.

[0031] This curable composition exhibits excellent stability over time (physical and optical properties), making it suitable for additive manufacturing processes, especially vat technologies. This curable composition enables to form a transparent material or article with excellent optical, chemical and mechanical performances.

[0032] Another advantage of the present invention is that the composition is free of carcinogenic, mutagenic or reprotoxic compounds (CMR compounds).

[0033] DETAILED DESCRIPTION OF THE INVENTION

[0034] In the present disclosure, the term “curable composition” refers to Ultra-Violet curable composition or Visible curable composition. More specifically, it means that said composition is a product in which monomers, oligomers, etc. are solidified, hardened through a polymerization reaction by Ultra-Violet rays or visible rays. The terms “cure” and “harden” can be used interchangeably.

[0035] In the present disclosure, unless otherwise specified, an optical article / material / element is understood to be transparent when the observation of an image through said optical article / material / element is perceived with no significant loss of contrast, that is, when the formation of an image through said optical article / material / element is obtained without adversely affecting the quality of the image. This definition of the term “transparent” can be applied to all objects qualified as such in the description, unless otherwise specified.

[0036] In the present disclosure, the term “difunctional” in e.g. difunctional polymerizable compound means that the polymerizable compound includes two polymerizable groups. In the present disclosure, the term “polyfunctional” in e.g. polyfunctional polymerizable compound means that the polymerizable compound includes more than two polymerizable groups.

[0037] In the present disclosure, unless specified otherwise, the term “alkyl” refers to a linear or branched chain monovalent saturated aliphatic hydrocarbon radical of 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, more preferably of 1 to 4 carbon atoms.

[0038] For example, the term “linear or branched saturated alkyl” refers to methyl, ethyl, propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl or and t-butyl, preferably methyl (-CH3) and ethyl (- CH2-CH3).

[0039] In the present disclosure, the term “alkylene” represents any divalent radical of a linear or branched hydrocarbon chain comprising 1 to 12 carbon atoms. Examples of C1-C12 alkylene groups include C1-C4 alkylene groups such as -CH2-, -(CH2)2-, -(CH2)3-, -(CH2)4-, -CH(CH3)-, -CH(CH3)-CH2-, -CH2-CH(CH3)-, -(CH2)2-CH(CH3)-, or

[0040] -CH2-CH(CH3)-CH2- as well as -(CH2)5-, -(CH2)6-,

[0041] -(CH2)2-CH(CH3)-(CH2)2-, -(CH2)3-CH(CH3)-CH2-, -(CH2)7-, -(CH2)8- -(CH2)9-, -(CH2)IO-, - (CH2)II-, -(CH2)i2-.

[0042] In the present disclosure, the term “alkoxylene” refers to -O(alkylene) group, wherein the alkylene is as defined above.

[0043] In the present disclosure, the term “alkoxy” refers to -O(alkyl) group, wherein the alkyl is as defined above.

[0044] In the present disclosure, the term “alkyleneoxy” represents a radical of formula -O(R'O)R wherein R' is a C1C12 alkylene, R is a C1C12 alkyl. Examples of (C1-C12 alkylenoxy) groups include OCH2OCH3. The term “polyalkyleneoxy” represents a radical of formula - O(R'O)mR wherein R' is a C1C12 alkylene, R is a C1C12 alkyl and m is an integer from 1 to 12. Examples of (C1-C12 alkylenoxy) groups include -OCH2 -CH2-O-CH3.

[0045] As used herein, the term “acryloxy” or “acryloxy group” means -O(CO)-CH2=CH2.

[0046] As used herein, the term “methacryloxy” or “methacryloxy group” means -O(CO)- CH2=CHCH3.

[0047] In the present disclosure, the term “cycle” or “ring” corresponds to a compound in which one or more series of atoms in the compound is connected to form a ring. Rings may vary in size from three to many atoms, for example 5 or 6 atoms and include examples where all the atoms are carbon (i.e., are carbocycles), or where both carbon and non-carbon atoms are present (heterocyclic compounds). More precisely, a “heterocyclic compound or ring structure” is a cyclic compound that has atoms of at least two different elements as members of its ring(s).

[0048] As used herein, the term “non-aromatic carbocycle” refers to a divalent monocyclic hydrocarbon ring or fused polycyclic hydrocarbon rings, which may comprise one or more unsaturations. In one variant, the non-aromatic carbocycle does not show any unsaturation but is a saturated ring. Examples of non-aromatic carbocycle include cycloalkylene. The expression "cycloalkylene" represents any divalent radical of a monocyclic or polycyclic 3 to 12 membered carbocycle. Examples of C3-C12 alkylene groups include cyclopropylene, cyclopentylene, cyclohexylene, cycloheptylene, cyclodecylene and decahydronaphthylene. The non-aromatic carbocycle can also be for example a fused polycyclic ring such as a tricyclodecane derivative. The non-aromatic carbocycle can be substituted, for example by a linear or branched alkyl.

[0049] In the present disclosure, the term “non-aromatic heterocycle” refers to a divalent monocyclic ring or fused polycyclic rings, which comprise at least one heteroatom being oxygen atom, nitrogen atom or sulfur atom and which may comprise one or more unsaturations. When the heterocycle comprises more than one heteroatom, each heteroatom is, identically or differently of each other, oxygen atom, nitrogen atom or sulfur atom. For example, the heterocycle comprises between 1 to 3 heteroatoms.

[0050] For example, non-aromatic heterocycle includes, but is not limited to, heterocycloalkylene. The non-aromatic heterocycle as used herein can form for example a dioxane, a trioxane, a tetrahydrofuran, a thiane, a pyrrolidine etc.

[0051] Unless mentioned otherwise, the groups and radicals defined hereinabove may be unsubstituted or substituted by one or more substituents.

[0052] The term “substituted” refers to the specified group or moiety bearing one or more substituents, for example by a hydroxyl group (-OH) and / or an alkyl group. The term “optionally substituted” refers to the specified group or moiety being unsubstituted or substituted by one or more substituents.

[0053] Unless otherwise specified, the terms "compound" and "component" are considered interchangeable throughout the present disclosure.

[0054] The curable composition of the present invention comprises at least one photoinitiator and at least one polymerizable composition.

[0055] The polymerizable composition of the present invention contains at least a mixture of two polymerizable components: a first polymerizable component and a second polymerizable component. In the present invention, the first polymerizable component is an aliphatic urethane (meth)acrylate oligomer. Such component increases the flexibility of the curable composition without unduly increasing its viscosity and reduces the total shrinkage of the curable composition since it can be able to form bonds with other molecules. As a result, the resulting polymer is less brittle.

[0056] The term “urethane acrylate oligomer” refers to a type of synthetic polymer that combines the properties of urethane and acrylate groups to form a versatile material used in a variety of applications such as coatings, adhesives, inks, and composites. The urethane segment typically provides toughness and flexibility, while the acrylate portion offers fast curing times and the ability to form rigid and durable networks upon curing.

[0057] The oligomer of the “urethane acrylate oligomer” can be composed of short chains that are formed by reacting together an isocyanate group (-NCO) from the urethane chemistry with a hydroxyl group (-OH) to build the "urethane" linkages, and then further reacting with acrylate functional groups which allow the oligomer to undergo photopolymerization when exposed to UV light.

[0058] The urethane (meth)acrylate oligomer can be obtained by reacting a polyisocyanate with a hydroxyl group-containing (meth)acrylate and, if necessary, with a polyol other than the hydroxyl group-containing (meth)acrylate, and has an acryloyl group (CH2=CHC0‘) and / or a methacryloyl group (CH=C(CH3)-C0‘) as functional groups in the molecule, and a urethane bond (-NH-COO-).

[0059] In particular, the first polymerizable component may preferably comprise at least two (meth)acrylates groups. The first polymerizable component is preferably difunctional (meth)acrylate or polyfunctional (meth)acrylate. Such polymerizable acrylates component enable to get a composition with a good stability over time (stable physical and chemical properties). Notably, the first polymerizable component can preferably be an aliphatic urethane di(meth)acrylate oligomer, an aliphatic urethane tri(meth)acrylate oligomer or a combination thereof.

[0060] In particular, suitable commercially available first polymerizable components include, but are not limited to, UV-841, UV-71, UV-72, UV-73, UV-820, UV-822, and UV-831 (trade names, all manufactured by Ohtake Meishin Chemical Co., Ltd.), HITAROID 4860-CH37, HITAROID 4863 (trade names, manufactured by Hitachi Chemical Co., Ltd.), EBECRYL 210, EBECRYL 215, EBECRYL 230, EBECRYL 244, and EBECRYL 250. YL245, EBECRYL270, EBECRYL284, EBECRYL285, EBECRYL8402, EBECRYL9270 (product names, all manufactured by Daicel-Allnex Co., Ltd.), New Frontier R-1204, New Frontier R-1214, New Frontier R-1220, New Frontier GX-8780 J (product names, all manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Shiko UV -2000B, Shikou UV-3000B, Shikou UV- 3200B, Shikou UV-3300B, Shikou UV-3310B, Shikou UV-6630B, Shikou UV-6640B (product names, all manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), UA- 122P, U-200PA, UA-4200 (product names, all manufactured by Shin-Nakamura Chemical Co., Ltd.), Art Resin CMB-002, Art Resin UN-333, Art Resin UN- 2600, Art Resin UN-2700, Art Resin UN-6304, Art Resin UN-7600, Art Resin UN-9000PEP, Art Resin UN-9200A (product names, all manufactured by Negami Chemical Industries, Ltd.), Photomer 6010, Photomer 6210, Photomer 6230, Photomer 6891 , Photomer 6893-20R (product names, all manufactured by IGM) and combinations thereof.

[0061] In particular, the first polymerizable component can preferably be: propenoic acid, 2-hydroxyethyl ester, polymer with 1 ,1"-methylenebis[4- isocyanatocyclohexane] and 2-oxepanone (CAS N°52404-33-8, product name Photomer 6710, manufactured by IGM); hexanoic acid, 6-[[[[[1 ,3,3-trimethyl-5-[[[[6-oxo-6-[2-[(1-oxo-2- propenyl)oxy]ethoxy]hexyl]oxy]carbonyl]amino]cyclohexyl]methyl]amino]carbonyl]oxy]-,2- [(1-oxo-2-propenyl)oxy]ethylester (CAS n° 119107-13-0, Product name Photomer 6891 , manufactured by IGM); or

[0062] - a mixture thereof.

[0063] In the present invention, the second polymerizable component may be regarded as the rigid monomer of the polymerizable composition, the monomer or component enabling to get a resulting polymer with a relatively high glass transition temperature (Tg) and a good storage modulus.

[0064] In particular, the second polymerizable component can preferably comprise at least two (meth)acrylates groups. Notably, this component can preferably be difunctional (meth)acrylates or polyfunctional (meth)acrylates. Such polymerizable acrylates components enable to get a composition with a good stability over time (stable physical and chemical properties).

[0065] In particular, the second polymerizable component can typically be of formula (I):

[0066] Wherein,

[0067] Ri is a non-aromatic carbocycle or non-aromatic heterocycle wherein the cycle comprising 3 to 20 atoms and is optionally substituted by at least one linear or branched saturated alkyl having 1 to 10 carbon atoms and / or at least one acryloxy and / or one methacryloxy group;

[0068] R2 and R3, identical or different, are independently an alkylene, an alkoxylene, an alkyleneoxy, a poly(alkylene) or a poly(alkoxylene) or a poly(alkyleneoxy), wherein the alkylene and the alkoxylene and the alkylenoxy are linear or branched, saturated and having 1 to 10 carbon atoms and wherein the alkylene, the alkoxylene, the alkylenoxy, the poly(alkylene), the poly(alkoxylene) or the poly(alkylenoxy) is optionally substituted, for example by at least one hydroxyl, and / or one acryloxy and / or one methacryloxy group;

[0069] R4, Rs, Re, R9, R10 and Rn, identical or different, are independently hydrogen or a linear or branched saturated alkyl having 1 to 4 carbon atoms, preferably independently a hydrogen or -CH3; m and p, identical or different, are independently 0 or 1.

[0070] In particular, the second polymerizable component can preferably be of formula (I) with R4, Rs, Re, R9, R10 and Rn independently a hydrogen or -CH3.

[0071] Notably, the second polymerizable component can preferably be of formula (I) wherein m and p, identical, are equal to 1 and R2 and R3are independently an alkylene, wherein the alkylene is linear or branched, saturated and having 1 to 10 carbon atoms and is optionally substituted, for example by at least one hydroxyl, and / or one acryloxy and / or one methacryloxy group, preferably the alkylene is -CH2-. In particular, when m=p=0, the second polymerizable component can typically be of formula (l-A):

[0072] Wherein

[0073] R1 , R4, Rs, Re, R9, R10 and Rn are as defined above.

[0074] In particular, when m=p=1 , the second polymerizable component can typically be of formula

[0075] (l-B)

[0076] Wherein

[0077] R1, R2, R3, R4, Rs, Re, R9, R10 and Rn are as defined above.

[0078] In particular, when m=p=1 and R2 and R3 are -CH2, the second polymerizable can typically be of formula (l-C):

[0079] (l-C)

[0080] Wherein

[0081] R1 , R4, Rs, Re, R9, R10 and Rn are as defined above.

[0082] For example, the second polymerizable component can preferably be tricyclo[5.2.1.02’6]decanedimethanol diacrylate, 2-[5-[(acryloyloxy)methyl]-5-ethyl-1 ,3- dioxan-2-yl]-2-methylpropyl acrylate (CAS n° 87320-05-6), or a mixture thereof, more preferably tricyclo[5.2.1.02’6]decanedimethanol diacrylate.

[0083] In particular, the polymerizable composition can preferably have at least one of the following characteristics:

[0084] - the first polymerizable component is propenoic acid, 2-hydroxyethyl ester, polymer with 1 ,1"-methylenebis[4- isocyanatocyclohexane] and 2-oxepanone (CAS n° 52404-33-8)', or hexanoic acid, 6-[[[[[1 ,3,3-trimethyl-5-[[[[6-oxo-6-[2-[(1-oxo-2- propenyl)oxy]ethoxy]hexyl]oxy]carbonyl]amino]cyclohexyl]methyl]amino]carbonyl]oxy]-,2- [(1-oxo-2-propenyl)oxy]ethylester (CAS n° 119107-13-0)',

[0085] - the second polymerizable component is tricyclo[5.2.1.02’6]decanedimethanol diacrylate or -[5-[(acryloyloxy)methyl]-5-ethyl-1 ,3-dioxan-2-yl]-2-methylpropyl acrylate.

[0086] The proportion of the first polymerizable component and second polymerizable component may be adjusted to tune the strength and / or flexibility of the resulting crosslinked polymer. By increasing the amount of the first polymerizable component, a more flexible polymer may be obtained, while increasing the amount of the second polymerizable component, a tougher polymer may be obtained.

[0087] Advantageously the polymerizable composition contains at least a mixture of:

[0088] - 20 to 80 weight% of the first polymerizable component

[0089] - 20 to 80 weight% of the second polymerizable component, with the weight percentage (weight%) based on the total weight of the polymerizable composition.

[0090] In particular, the polymerizable composition can preferably contain 20 to 60 weight%, 20 to 40 weight%, 40 to 80 weight% or 40 to 60 weight% of the first polymerizable component, with the weight percentage (weight%) based on the total weight of the polymerizable composition.

[0091] In particular, the polymerizable composition can preferably contain 20 weight%, 25 weight%,

[0092] 30 weight%, 35 weight%, 40 weight%, 45 weight%, 50 weight%, 55 weight%, 60 weight%, 65 weight%, 70 weight%, 75 weight% or 80 weight% of the first polymerizable component, with the weight percentage (weight%) based on the total weight of the polymerizable composition.

[0093] In one embodiment of the invention, the polymerizable composition can preferably comprise 20 to 60 weight% of the first polymerizable component, preferably 40 weight%, with the weight percentage (weight%) based on the total weight of the polymerizable composition.

[0094] In particular, the polymerizable composition can preferably contain 20 to 60 weight%, 20 to 40 weight%, 40 to 80 weight% or 40 to 60 weight% of the second polymerizable component, with the weight percentage (weight%) based on the total weight of the polymerizable composition.

[0095] In particular, the polymerizable composition can preferably contain 20 weight%, 25 weight%, 30 weight%, 35 weight%, 40 weight%, 45 weight%, 50 weight%, 55 weight%, 60 weight%, 65 weight%, 70 weight%, 75 weight% or 80 weight% of the second polymerizable component, with the weight percentage (weight%) based on the total weight of the polymerizable composition.

[0096] In one embodiment of the invention, the polymerizable composition can preferably comprise 20 to 60 weight% of the second polymerizable component, preferably 60 weight%, with the weight percentage (weight%) based on the total weight of the polymerizable composition.

[0097] In particular, the polymerizable composition can preferably comprise 30 weight%, 40 weight% or 45 weight% of the first polymerizable component and / or 55 weight%, 60 weight% or 70 weight% of the second polymerizable component, preferably 40 weight% of the first polymerizable component and / or 60 weight% of the second polymerizable component, with the weight percentage (weight%) based on the total weight of the polymerizable composition.

[0098] Third, ppl merizabje component

[0099] The polymerizable composition of the present invention contains at least a mixture of three polymerizable components: a first polymerizable component, a second polymerizable component

[0100] In the present invention, the third polymerizable component is a (meth) acrylate monomer of formula (II):

[0101] Wherein, R12 is a non-aromatic carbocycle or non-aromatic heterocycle wherein the cycle comprising 3 to 20 atoms and is optionally substituted by at least one linear or branched saturated alkyl having 1 to 10 carbon atoms;

[0102] R13 is an alkylene, an alkoxylene, an alkyleneoxy, a poly(alkylene) or a poly(alkoxylene) or a poly(alkyleneoxy), wherein the alkylene and the alkoxylene and the alkylenoxy are linear or branched, saturated and having 1 to 10 carbon atoms and wherein the alkylene, the alkoxylene, the alkylenoxy, the poly(alkylene), the poly(alkoxylene) or the poly(alkylenoxy) is optionally substituted, for example by at least one hydroxyl, and / or one acryloxy and / or one methacryloxy group;

[0103] RM, RIS and Rie, identical or different, are independently hydrogen or a linear or branched saturated alkyl having 1 to 4 carbon atoms, preferably independently a hydrogen or -CHs; n is 0 or 1 , wherein when n=0 the acrylate group is directly bonded to R12 and when n=1 the acrylate group is bonded to R13.

[0104] The (meth) acrylate monomer of formula (II) can be qualified as a diluent monomer. Preferably, this diluent monomer can have a low viscosity. This monomer enhances the flexibility of the resulting polymer. It can also lower the water uptake of the resulting polymer over the time without affecting too much the mechanical performances of the resulting polymer.

[0105] In particular, the (meth)acrylate component of formula (II) can show R14, R15 and R16, being independently a hydrogen or -CH3.

[0106] In particular, the (meth) acrylate component of formula (II) can have n equal to 0.

[0107] In particular, when n is equal to 0, the (meth)acrylate component can be of formula (ll-A):

[0108] (ll-A)

[0109] Wherein R12, R14, R15 and R16 are as defined above.

[0110] In particular, when n is equal to 1 , the (meth)acrylate component can be of formula (ll-B):

[0111] (ll-B) Wherein R12, R13, R14, R15 and R16 are as defined above.

[0112] In one embodiment of the invention, the (meth)acrylate monomer of formula (II) can preferably have a structure similar to the structure of the second polymerizable component. The expression “have a structure similar” means that R12 is similar to R1, considering the number of carbons in the non-aromatic cycle, the presence of heteroatoms and / or the optional substituents.

[0113] Preferably, the (meth)acrylate component of formula (II) can be isobornyl methacrylate (IBOMA), isobornyl acrylate (IBOA) or a mixture thereof.

[0114] In particular, the polymerizable composition can comprise 0.1 to 20 weight% of the (meth)acrylate component of formula (II), based on the total weight of the polymerizable composition. Notably, the polymerizable composition can comprise 1 to 20 weight%, 4 to 20 weight%, 5 to 20 weight%, 5 to 17 weight%, 10 to 20 weight%, 15 to 20 weight%, 0.1 to 17 weight%, 0.1 to 15 weight%, 4 to 17 weight%, 4.8 weight% to 16.7 weight% or 4 to 15 weight% of the (meth)acrylate component of formula (II), based on the total weight of the polymerizable composition. For example, the polymerizable composition can comprise 0.1 weight%, 4 weight%, 4.8 weight%, 5 weight%, 9.1 weight%, 10 weight%, 16.7 weight%, 17 weight% or20 weight% of the (meth)acrylate component of formula (II), based on the total weight of the polymerizable composition.

[0115] In particular, the polymerizable composition can preferably comprise 0.1 to 20 weight%, more preferably 4 to 20 weight% of the (meth)acrylate component of formula (II), based of the total weight of the polymerizable composition.

[0116] <Polymerizable initiator

[0117] The curable composition of the present invention can preferably include at least one polymerization initiator, more precisely at least one photopolymerization initiator.

[0118] The term “photopolymerization initiator” and “photoinitiator” can be used interchangeably. Said photoinitiator is preferably a free-radical photoinitiator. Specific examples of free- radical initiator suitable for the present invention include, but are not limited to, bis(2,4,6- trimethyl benzoyl)phenylphosphine oxide (IRGACURE® 819), 2,4,6-trimethylbenzoyl diphenyl phosphine (TPO), 2-hydroxy-2-methy 1-1-pheny 1-1-propane (DAROCUR® 1173) or benzophenone (BP), 1-Hydroxy cyclohexyl phenyl ketone or a combinations thereof. Among them, bis(2,4,6-trimethyl benzoyl)phenylphosphine oxide (IRGACURE® 819) is particularly preferred because it enables to limit the Yellowness index (Yl) of the cured composition.

[0119] The curable composition can be crosslinked by UV radiation; including near UV / visible radiation, preferably by a UV / visible or near UV / visible lamp; by laser or by LED, more preferably by a near UV / visible lamp.

[0120] Since the (meth)acrylate composition of the present invention is cured under air, the concentration of the free-radical photoinitiator is preferably equal or greater than 0,1 % by weight of the total weight of the UV-curable composition and equal or less than 10% by weight of the total weight of the UV-curable composition, preferentially equal or greater than 0.1 % by weight of the total weight of the UV-curable composition and equal or less than 5% by weight of the total weight of the UV-curable composition, more preferentially equal or greater than 0.1% by weight of the total weight of the UV-curable composition and equal or less than 3% by weight of the total weight of the UV-curable composition. Notably, the concentration of the free-radical photoinitiator can preferably be equal to 0.5% by weight of the total weight of the UV-curable composition.

[0121] In particular, the concentration of the photoinitiator is between 0.1 weight% to 5 weight%, preferably between 0.1 weight% to 3 weight%, more preferably 0.5 weight%, based on the total weight of the curable composition.

[0122] In particular, a polymerization accelerator (sensitizer) such as a thermal polymerization initiator, also called a thermal initiator, can be used in addition to the photoinitiator (i.e in combination with the photoinitiator).

[0123] Notably, in one embodiment of the invention, the curable composition can further comprise a thermal initiator, said thermal initiator being preferably benzoyl peroxide.

[0124] In particular, the concentration of the thermal initiator can be between 0.1 weight% to 5 weight%, preferably between 0.1 weight% to 3 weight%, based on the total weight of the curable composition.

[0125] In one embodiment of the invention, the curable composition can comprise at least two polymerization initiators different from each other. For example, the curable composition can comprise at least two different photoinitiators or a mixture of at least one photoinitiator and one thermal polymerization initiator.

[0126] In particular, when the temperature of dissociation of the thermal polymerization initiator is lower than the temperature of the post curing-oven, the curable composition can preferably contain at least one photoinitiator and at least one thermal polymerization initiator. The thermal polymerization initiator helps to create more bridges between the monomers comprised in the curable composition and enhance the mechanical behaviour of the resulting polymer. In particular, the curable composition can comprise at least two different photoinitiators, such as 2,4,6-trimethylbenzoyl diphenyl phosphine and bis(2,4,6-trimethyl benzoyl)phenylphosphine oxide. As a result, the glass transition temperature (Tg) and a good storage modulus of the resulting polymer can be enhanced.

[0127] <Others polymerizable components>

[0128] In one embodiment of the invention, the polymerizable composition can further comprise an aliphatic (meth)acrylate of formula (III):

[0129] Wherein,

[0130] R17 is an alkylene, an alkoxylene, an alkyleneoxy, a poly(alkylene), a poly(alkoxylene) or a poly(alkyleneoxy), wherein the alkylene, the alkoxylene, the alkyleneoxy are linear or branched, saturated and having 1 to 20 carbon atoms, preferably 2 to 15 atoms and wherein the alkylene, the alkoxylene, the alkyleneoxy, the poly(alkylene), the poly(alkoxylene) or the poly(alkyleneoxy) is optionally substituted for example by at least one hydroxyl or a linear or branched saturated alkyl, at least one hydroxyl, at least one acryloxy and / or at least one methacryloxy group;

[0131] Ri8, R19, R20, R21 , R22 and R23, identical or different, are independently a hydrogen or a linear or branched saturated alkyl having 1 to 4 carbon atoms, preferably independently a hydrogen or -CH3.

[0132] The aliphatic (meth)acrylate of formula (III) can preferably have a low viscosity. By adding this monomer of formula (III), the one skilled in the art is able to adjust the overall viscosity of the curable composition accordingly to the additive manufacturing technology used. This monomer also enhances the flexibility of the resulting polymer.

[0133] In particular, suitable examples of aliphatic (meth)acrylate of formula (III) include, but are not limited to, ethylene glycol diacrylate (EGDA), ethylene glycol dimethacrylate (EGDMA), 1 ,6-hexanediol diacrylate, 1 ,10-decanediol diacrylate, 1,6-Hexanediol dimethacrylate, 1 ,10-Decanediol di methacrylate, 1 ,4 Butanediol Dimethacrylate, 2-hydroxy-3-methacryl- propyl acrylate, 3-methyl-1 ,5-pentanediol diacrylate, their derivatives, and a mixture thereof, preferably is 1 ,6-hexanediol diacrylate or 1 ,10-decanediol diacrylate. In particular, the polymerizable composition can comprise 0.1 to 20 weight% of the aliphatic (meth)acrylate component of formula (III), based on the total weight of the polymerizable composition. Notably, the polymerizable composition can comprise 1 to 20 weight%, 4 to 20 weight%, 5 to 20 weight%, 5 to 17 weight%, 10 to 20 weight%, 15 to 20 weight%, 0.1 to 17 weight%, 0.1 to 15 weight%, 4 to 17 weight%, 4.8 weight% to 16.7 weight% or 4 to 15 weight% of the aliphatic (meth)acrylate component of formula (III), based on the total weight of the polymerizable composition. For example, the polymerizable composition can comprise 0.1 weight%, 4 weight%, 4.8 weight%, 5 weight%, 9.1 weight%, 10 weight%, 16.7 weight%, 17 weight% or 20 weight% of the (aliphatic (meth)acrylate component of formula (III), based on the total weight of the polymerizable composition.

[0134] In particular, the polymerizable composition can preferably comprise 0.1 to 20 weight%, more preferably 4 to 20 weight% of the aliphatic (meth)acrylate component of formula (III), based of the total weight of the polymerizable composition.

[0135] In another embodiment of the invention, the polymerizable composition can further comprise an aliphatic (meth)acrylate of formula (IV): Wherein,

[0136] R24 is an alkyl, an alkoxy, an alkyleneoxy, a poly(alkyl), a poly(alkoxy) or a poly(alkyleneoxy), wherein the alkyl, the alkoxy, the alkyleneoxy are linear or branched, saturated and having 1 to 20 carbon atoms, preferably 2 to 15 atoms and wherein the alkyl, the alkoxy, the alkyleneoxy, the poly(alkyl), the poly(alkoxy) or the poly(alkyleneoxy) is optionally substituted for example by at least one hydroxyl or a linear or branched saturated alkyl and / or at least one hydroxyl;

[0137] R25, R26 and R27, identical or different, are independently a hydrogen or a linear or branched saturated alkyl having 1 to 4 carbon atoms, preferably independently a hydrogen or -CH3.

[0138] The aliphatic (meth)acrylate of formula (IV) can preferably have a low viscosity. By adding this monomer of formula (IV), the one skilled in the art is able to adjust the overall viscosity of the curable composition accordingly to the additive manufacturing technology used. This monomer also enhances the flexibility of the resulting polymer and / or reduces the brittleness of the resulting polymer.

[0139] In particular, suitable examples of aliphatic (meth)acrylate of formula (IV) include, but are not limited to, 2-Hydroxyethyl acrylate (HEA), methyl methacrylate (MMA), Octyl Decyl acrylate (CAS n°911-295-9), Tridecyl acrylate (CAS N°911-296-4), Isodecyl acrylate, their derivatives, and a mixture thereof.

[0140] In particular, the polymerizable composition can comprise 0.1 to 20 weight% of the aliphatic (meth)acrylate component of formula (IV), based on the total weight of the polymerizable composition. Notably, the polymerizable composition can comprise 1 to 20 weight%, 4 to 20 weight%, 5 to 20 weight%, 5 to 17 weight%, 10 to 20 weight%, 15 to 20 weight%, 0.1 to 17 weight%, 0.1 to 15 weight%, 4 to 17 weight%, 4.8 weight% to 16.7 weight% or 4 to 15 weight% of the aliphatic (meth)acrylate component of formula (IV), based on the total weight of the polymerizable composition. For example, the polymerizable composition can comprise 0.1 weight%, 4 weight%, 4.8 weight%, 5 weight%, 9.1 weight%, 10 weight%, 16.7 weight%, 17 weight% or 20 weight% of the (aliphatic (meth)acrylate component of formula (IV), based on the total weight of the polymerizable composition.

[0141] In particular, the polymerizable composition can preferably comprise 0.1 to 20 weight%, more preferably 4 to 20 weight% of the aliphatic (meth)acrylate component of formula (IV), based of the total weight of the polymerizable composition.

[0142] In particular, the polymerizable composition can contain, or eventually consist in, at least a mixture of an aliphatic urethane (meth)acrylate oligomer as first polymerizable component and a component of formula (I) as second polymerizable component; or at least a mixture of an aliphatic urethane (meth)acrylate oligomer as first polymerizable component, a component of formula (I) as second polymerizable component and a (meth) acrylate monomer of formula (II); or at least a mixture of an aliphatic urethane (meth)acrylate oligomer as first polymerizable component, a component of formula (I) as second polymerizable component and an aliphatic (meth)acrylate of formula (III); or at least a mixture of an aliphatic urethane (meth)acrylate oligomer as first polymerizable component, a component of formula (I) as second polymerizable component and an aliphatic (meth)acrylate of formula (IV); or at least a mixture of an aliphatic urethane (meth)acrylate oligomer as first polymerizable component, a component of formula (I) as second polymerizable component and a mixture of at least two components selected among (meth) acrylate monomers of formula (II), aliphatic (meth)acrylates of formula (III) and aliphatic (meth)acrylates of formula (IV).

[0143] <Other components>

[0144] The curable composition may comprise other known additives, other components which are conventionally employed in polymerizable compositions intended for manufacturing optical articles, in particular ophthalmic lenses, in conventional proportions such as solvents, dyes, non-reactive light absorbers, levelling agents, adhesion additives, wetting agents, rheology additives, oxygen scavenger, defoamers and air release additives. These additives and their amounts are selected according to the desired application. For example, these additives can be added to compensate the Yellowness index, to colour the optical article or to control the viscosity of the curable composition.

[0145] In particular, the curable composition can further comprise at least one inhibitor, said inhibitor being preferably 2,6-di-(tert-butyl)-4-methylphenol (BHT) or 4- methoxyphenol (MEHQ). In particular, the concentration of the inhibitor can be between 0.1 weight% to 5 weight%, preferably between 0.1 weight% to 3 weight%, based on the total weight of the curable composition.

[0146] In particular, the curable composition can further comprise at least one UV absorber, said UV absorber being preferably 2-(2'-hydroxy-5'-tert-octyllphenyl)benzotriazole, 1-(4-tert- Butylphenyl)-3-(4-methoxyphenyl) 1 ,3-propanedione) or phenazine, more preferably -(2'- hydroxy-5'-tert-octyllphenyl)benzotriazole. In particular, the concentration of the UV absorber can be between 0.1 weight% to 2 weight%, preferably between 0.1 weight% to 1 .5 weight%, based on the total weight of the curable composition.

[0147] In particular, the curable composition is preferably solvent-free, preferably free of organic solvent. “Free of” a solvent means that no solvent is substantially contained. The content thereof is preferably less than 0.1 weight% of the total weight of the curable composition.

[0148] In particular, the curable composition can further comprise color balancing absorbing dyes or a plurality of color balancing absorbing dyes, each of which reducing transmittance in a different region of the visible spectrum.

[0149] The viscosity of the curable composition of the present invention (Brookfield viscosity) has no particular limit because it can be adjusted depending on the purpose and application devices. However, the UV-curable composition may preferably have a viscosity at 25°C equal to or less than 1200 cP and preferably equal to or less than 1000 cP. Notably, the viscosity of the curable composition can be equal to or less than 800 cP or equal to or less than 900 cP. The viscosity is typically measured with Brookfield Viscometer, SC4-18 modulus according to ISO 3219 method.

[0150] 5.5. The optica).

[0151] The present invention also relates to the material obtained by curing the curable composition, said material exhibiting good optical, good chemical performances and good mechanical performances.

[0152] The curing of the curable composition comprises the irradiation of curable composition. This irradiation enables the polymerization of the at least two polymerizable components detailed above. The curing of the curable composition may advantageously be followed by a thermal treatment.

[0153] The optical material according to the present invention preferably has a glass transition temperature (Tg) higher than or equal to 80°C. Notably, the optical material preferably has a glass transition temperature (Tg) higher than or equal to 85°C, more preferably higher than or equal 90°C, still more preferably higher than or equal to 100°C and even more preferably higher than or equal to 120°C. The Tg measure is typically carried out by dynamic mechanical analysis (DMA) on a planar 60mmx10mmx2mm sample.

[0154] The optical material according to the present invention preferably has a coefficient of linear thermal expansion (GET) equal to or less than about 120 pm / (m.°C), more preferably equal to or less than about 80 pm / (m.°C), still more preferably of about 80 pm / (m.°C). The GET is typically measured by ThermoMechanical Analyser (TMA) in accordance with ASTM E831 .

[0155] In the present disclosure, the term “about” is defined as the measurement incertitude.

[0156] The optical material according to the present invention preferably has a storage modulus (E’) of higher than 2.2 GPa at 25°C and equal or less than 5 GPa. The storage modulus measure is typically carried out by dynamic mechanical analysis (DMA) on a planar 6 cm*1 cm*2 mm (thickness) sample.

[0157] The optical material preferably has a refractive index at 550 nm of about 1.5 and preferably an Abbe number (Ve) of higher or equal to 38 when it is measured using the green line (e) of a mercury lamp at A=546,1 nm. Unless otherwise specified, the refractive indexes referred to in the present application are expressed at 25°C at a wavelength of 550 nm. When the optical material has 2 mm of thickness, the optical material according to the present invention preferably has a relative light transmission factor in the visible spectrum (Tv) of preferably equal or greater than 80%, more preferably equal or greater than 85% when the curable composition is dye-free, and still more preferably equal or greater than 89% when the curable composition is dye-free. The Tv factor, also called “luminous transmission" of the system, is such as defined in ISO standard 13666:1998 and is measured according to the standard ISO 8980-3. It is defined as the average transmission in the 380-780 nm wavelength range that is weighted according to the sensitivity of the eye at each wavelength of the range and measured under D65 illumination conditions (daylight). Transmissions are expressed for 2 mm thick optical articles, measured at the center of the optical article and at a normal incidence of the light beam (0° from the normal).

[0158] The optical material according to the present invention preferably has a Yellowness index (Yi) of lower than 4, more preferably equal or lower than 1 .5. The yellowness index is measured according to ASTM E313.

[0159] In particular, the optical material can be defined as having at least one of the following characteristics:

[0160] - a refractive index at 550 nm of about 1 .5 at 25°C;

[0161] - an Abbe number (Ve) of higher or equal to 38 when it is measured using the green line (e) of a mercury lamp at A=546.1 nm;

[0162] - a Yellowness index (Yi) of lower than 4, more preferably equal or lower than 1 .5;

[0163] - a relative light transmission factor in the visible spectrum (Tv) equal to or higher than 90% when the optical material has 2 mm thickness;

[0164] - a storage modulus (E’) at 25°C equal to or greater than 2.2 GPa and equal to or less than 5 GPa;

[0165] - a storage modulus (E’) at 100°C equal to or greater than 100 MPa, preferably equal to or greater than 400 MPa;

[0166] - a glass transition temperature (Tg) higher than or equal to 80°C, preferably higher than or equal to 90°C, more preferably higher than 100°C;

[0167] - a coefficient of linear thermal expansion (GET) equal to or less than about 120 pm / (m.°C), more preferably equal to or less than about 80 pm / (m.°C);

[0168] - a water uptake after 24h equal to or less than 1 weight%, based on the total weight of the optical material;

[0169] - a water uptake after 2 months equal to or less than 2 weight%, based on the total weight of the optical material. The curable composition of the present invention is therefore particularly suitable for the manufacture of optical article, especially ophthalmic article, by additive manufacturing, especially vat technologies. .Q.P.ticaJJ..QP.hthalmic ields>>

[0170] The optical material of the invention can be used for the manufacturing of an optical element.

[0171] The optical element can be the bulk material, the substrate of an optical article, preferably an optical lens or lens blank, more preferably an ophthalmic lens or lens blank, such as a plastic eyeglass lens. The optical element can also be used as a coating or as a complementary optical member which is adjoined by gluing to a starting optical member, for example to a substrate or by building directly by additive manufacturing on said starting optical member. The starting optical member may be a substrate of the material of the present invention or of another material used for manufacturing ophthalmic lens substrates. Said optical element can be manufactured by using, for example, the technology disclosed in international applications W02015004383A1 and W02019002905A1.

[0172] A substrate, in the sense of the present invention, should be understood to mean an uncoated substrate, and generally has two main faces. The substrate may in particular be made of the present optical material having the shape of an optical article, for example an ophthalmic lens destined to be mounted in glasses. In this context, the term “substrate” is understood to mean the base constituent material of the optical article and more particularly of the optical lens. This material may act as support for a stack of one or more coatings or layers.

[0173] Although ophthalmic optics is a preferred field of the invention, it will be understood that this invention can be applied to optical articles of other types, such as, for example, lenses for optical instruments, in photography or astronomy, optical sighting lenses, ocular visors, optics of lighting systems, screens, glazing, windshields, sport masks, face shields, goggles, optical coatings or adhesives, etc.

[0174] In the present disclosure, the term of “ophthalmic lens” is used to mean a lens adapted to a spectacle frame to protect the eye and / or correct the sight. Said lens can be chosen from afocal, unifocal, bifocal, trifocal, progressive, piano, meaning an optical article without any notable optical power, solar and Fresnel lenses or any other kind of lenses having a discontinuous surface. If the optical article is an optical lens or an ophthalmic lens, it may be coated on its front main surface, rear main side, or both sides with one or more functional coatings. As used herein, the rear face of the substrate is intended to mean the face which, when using the article, is the nearest from the wearer's eye. It is generally a concave face. On the contrary, the front face of the substrate is the face which, when using the article, is the most distant from the wearer's eye. It is generally a convex face.

[0175] The ophthalmic lens of the invention may comprise functional coatings classically used in ophthalmics such as an impact-resistant and / or adhesion primer, an abrasion-resistant and / or scratch-resistant coating, an anti-reflection coating, an antistatic coating, an antisoiling coating, an anti-smudge coating, an anti-dust coating, an anti-fog coating, a water repellent coating, an interferential filter, a tinted coating, a mirror coating, and a combination of any of preceding compatible coatings, especially an impact-resistant primer coating coated with an abrasion and / or scratch-resistant coating.

[0176] « Method for the optical, el e m ent>>

[0177] The present invention also relates to a method for the manufacturing of an optical element, said method comprising the photopolymerization of the curable composition defined above. All embodiments of the curable composition detailed above are applicable to the method for the manufacturing of an optical element.

[0178] The method for the manufacturing of the optical element of the present disclosure preferably comprises an additive manufacturing process (or an additive manufacturing step). The method for the manufacturing of the optical element of the present disclosure preferably comprises a vat-photopolymerization three-dimensional (3D) printing. For example, this vat-polymerization 3D printing can be done through frontal photopolymerization (FPP), stereolithography (SLA) or digital light processing (DLP) process. This printed process can be a layer-by-layer printing process or a continuous printing process, such as Continuous Liquid Interface Product (CLIP) method. The method preferably comprises the technology disclosed in international applications W02015004383A1 and W02019002905A1. Another object of the present invention is the optical element obtained according to said method.

[0179] Thus, according to an embodiment of the present invention, the optical element is a 3- Dimensional (3D) element obtained by an additive manufacturing process, preferably by a method of manufacturing comprising a vat-photopolymerization three-dimensional (3D) printing.

[0180] The optical element can be a part of an optical article. It can be the substrate of an optical article or another layer of the stack constituting an optical article. The optical element according to the present invention is preferably an ophthalmic element.

[0181] A further object of the present invention is the ophthalmic lens comprising the ophthalmic element. In one variant, the ophthalmic element is the substrate of an ophthalmic lens. All embodiments of the optical article or the ophthalmic lens detailed above are applicable to the optical article or the ophthalmic lens comprising the optical element or the ophthalmic element.

[0182] EXAMPLES

[0183] Hereinafter, the present disclosure will be described by way of examples. However, the present disclosure should not be construed as being limited to these examples.

[0184] Curable compositions

[0185] Materials given in Table 1 below were used on the corresponding amounts presented in the table and were mixed together. For reference, a composition comprising only Tricyclo[5.2.1.02,6]-decanedimethanol diacrylate and bis(2,4,6-trimethyl benzoyl)- phenylphosphine oxide was used (Comp Ex.1). A composition comprising three polymerizable components without a component of formula (II) was also used as reference (Comp Ex. 4).

[0186]

[0187] Table 1

[0188] Characterizations of the curable compositions

[0189] The viscosity at 20°C and at 45°C of each composition was measured with Brookfield Viscometer, SC4-18 modulus according to ISO 3219. The results are given in Table 2. The refraction index of each composition at 550 nm was determined using Metricon instrument. The results ae given in Table 2.

[0190] Table 2 These results show that the compositions of Examples 1 to 4 have a higher viscosity and a lower refractive index than the reference composition Comp Ex. 1. These results also show that the composition of Example 1 has a higher viscosity than the composition Comp Ex. 4, which does not contain a component of formula (II). These results show that the compositions of Examples 1 to 4 have a viscosity suitable for vat technologies such as DLP-SLA and Fast, Precise and Predictable processes in additive manufacturing such as frontal photopolymerization patterning (F3P) and a low refractive index.

[0191] Polymerization of the compositions

[0192] Each composition of Examples 1-4 and Comp. Example 1-5 was used to manufacture a polymerized material by digital light processing stereolithography (DLP-SLA). Each layer of the material is polymerized by an UV irradiation at A= 365 nm using a Light-Emitting Diode (LED) Lamp. When all layers had polymerized to make the printed material, the material was removed from the vat containing the composition and was then immersed (i.e dipped) in a commercially available cleaning aqueous based solution to remove the non-polymerized composition from the surface of the material. The final polymerized material has a thickness of 2 mm. The conversion rates are reported in Table 3.

[0193] Table 3

[0194] These results show that the compositions of Examples 1 to 3 are polymerizable with a high conversion rate and thus suitable for vat technologies.

[0195] Optical properties

[0196] Optical properties of the polymerized materials obtained above were characterized. The results are given in Table 4.

[0197] The refraction index of each material at 550 nm was determined using Metricon instrument.

[0198] For each material, the relative light transmission factor in the visible spectrum (Tv), also called luminous transmittance, was characterized in compliance with the standard ISO 8980-3 using a spectrometer Cary 50 (Agilent). The Tv is defined in the standard ISO

[0199] 13666:1998 with the following formula

[0200] The Yellowness index (Yi) was determined according to ASTM E313 with a spectrometer Cary 50 (Agilent) and Essilor Transcalc calculation software. Indeed, the yellowness index was determined from the CIE tristimulus values X, Y, Z through the relation of formula (IV): ... 128X-106Z

[0201] Yl = -

[0202] Y

[0203] The Abbe number (Ve) of the material obtained from the composition of Comparative Example 2 was determined using the Metricon instrument and the following formula (II): Ve =JVe~1; with Nethe refraction index of the green line (e) of a mercury lamp at NFI -NC,

[0204] A=546;1 nm, Np the refraction index of the cadmium at A=480.0 nm and Nc the refraction index of the cadium at A=643.8nm. The measured Abbe number is 55, which is a suitable optical property for an optical article.

[0205] Table 4

[0206] These results show that the polymer obtained from the compositions of Example 1 to 4, i.e. the material obtained by the curing of the curable compositions of Examples 1 to 4, shows suitable optical properties for an optical article.

[0207] Mechanical properties

[0208] Mechanical properties of the polymerized materials obtained above were characterized. The results are given in Table 5.

[0209] The Glass Transition Temperatures (Tg) measure of each polymerized material was carried out by dynamic mechanical analysis with Dynamic Mechanical Analyzer (TA instruments), on a planar 60mmx10mmx2mm sample with a heating rate of 2°C / min.

[0210] The Storage Modulus (E’) of each polymerized material was determined using with Dynamic Mechanical Analyzer (TA instruments) on a planar 60mmx10mmx2mm sample at 25°C and at 100°C.

[0211] The impact resistance (static resistance at 100N (CEN Standard)) was determined for the polymers obtained from the compositions of Comparative Examples 2 and 3, more precisely using a load of 100 newtons on the convex surface of a coated lens made of the polymer obtained from either the composition of example 1 or the composition of example 2, for 10 seconds (lenses : sphere: +0.75 and Centre thickness: 2mm).

[0212] The results show that these polymers according to the invention, i.e. the materials obtained by the curing of the curable compositions of Examples 1 to 4, have a high Tg (Tg tan Delta > 100°C and preferably > 120°C) and a high storage modulus (at 25°C E’>1.5GPa, preferably E’>2.2 GPa and at 100°C E’>100MPa, preferably E’>200MPa) (see Example 1 to 4). These polymers remain processable after polymerization, which is a critical requirement for the fabrication of high-precision optical elements by additive manufacturing, where post-processing steps such as polishing, curing, or shaping are often essential to achieve the desired optical quality. The materials obtained by the curing of the curable compositions of Examples 1 to 4 have mechanical properties that are compatible with those of an optical article such as a lens. By contrast, when the polymerizable composition comprises an aliphatic urethane (meth)acrylate oligomer, a polymerizable component of formula (I), and a polymerizable component of formula (III), but lacks a component of formula (II), the resulting polymer displays insufficient mechanical properties. These are not suitable for use in optical articles such as lenses (see Comparative Example 4).

[0213] Chemical properties

[0214] The water uptake of each polymerized material was determined notably after 24 hours, 30 days and 2 months. Each polymerized material is dried in an oven at 50°C, then placed in a water-saturated oven at 50°C and weighed after 24 hours and then periodically until the plateau is reached. The results are reported in Table 6.

[0215] Table 6 The results show that the isononyl acrylate has the effect to lower the water uptake of the obtained polymer.

[0216] Based on these results, it can be concluded that the compositions of Example 1 to 4 are CMR-free compositions with good physical properties compatible with vat technologies and resulting in a polymer with mechanical, chemical and / or optical properties suitable for optical articles.

Claims

1. CLAIMS1. A curable composition comprising at least- one photoinitiator and- a polymerizable composition containing at least a mixture of:- 20 to 80 weight% of a first polymerizable component,- 20 to 80 weight% of a second polymerizable component, with the weight percentage (weight%) based on the total weight of the polymerizable composition and, wherein,• The first polymerizable component is an aliphatic urethane (meth)acrylate oligomer,• The second polymerizable component is of formula (I):WhereinRi is a non-aromatic carbocycle or non-aromatic heterocycle wherein the cycle comprising 3 to 20 atoms and is optionally substituted by at least one linear or branched saturated alkyl having 1 to 10 carbon atoms and / or at least one acryloxy and / or one methacryloxy group;R2 and R3, identical or different, are independently an alkylene, an alkoxylene, an alkyleneoxy, a poly(alkylene) or a poly(alkoxylene) or a poly(alkyleneoxy), wherein the alkylene and the alkoxylene and the alkylenoxy are linear or branched, saturated and having 1 to 10 carbon atoms and wherein the alkylene, the alkoxylene, the alkylenoxy, the poly(alkylene), the poly(alkoxylene) or the poly(alkylenoxy) is optionally substituted, for example by at least one hydroxyl, and / or one acryloxy and / or one methacryloxy group;R4, Rs, Re, R9, R10 and Rn, identical or different, are independently hydrogen or a linear or branched saturated alkyl having 1 to 4 carbon atoms, preferably independently a hydrogen or -CH3; m and p, identical or different, are independently 0 or 1 ; and wherein the polymerizable composition further comprises a (meth) acrylate monomer of formula (II):WhereinR12 is a non-aromatic carbocycle or non-aromatic heterocycle wherein the cycle comprising 3 to 20 atoms and is optionally substituted by at least one linear or branched saturated alkyl having 1 to 10 carbon atoms;R13 is an alkylene, an alkoxylene, an alkyleneoxy, a poly(alkylene) or a poly(alkoxylene) or a poly(alkyleneoxy), wherein the alkylene and the alkoxylene and the alkylenoxy are linear or branched, saturated and having 1 to 10 carbon atoms and wherein the alkylene, the alkoxylene, the alkylenoxy, the poly(alkylene), the poly(alkoxylene) or the poly(alkylenoxy) is optionally substituted, for example by at least one hydroxyl, and / or one acryloxy and / or one methacryloxy group;R14, R15 and R16, identical or different, are independently hydrogen or a linear or branched saturated alkyl having 1 to 4 carbon atoms, preferably independently a hydrogen or -CHs; n is 0 or 1 , wherein when n=0 the acrylate group is directly bonded to R12 and when n=1 the acrylate group is bonded to R13.

2. The curable composition according to claim 1 , wherein the first polymerizable component is an aliphatic urethane di(meth)acrylate oligomer, an aliphatic urethane tri(meth)acrylate oligomer or a combination thereof.

3. The curable composition according to any one of the preceding claims, wherein the second polymerizable component is of formula (I) with R4, Rs, Rs, R9, R10 and Rn independently a hydrogen or -CH3.

4. The curable composition according to any one of the preceding claims, wherein m and p, identical, are equal to 1 and R2 and R3 are independently an alkylene, wherein the alkylene is linear or branched, saturated and having 1 to 10 carbon atoms and is optionally substituted, for example by at least one hydroxyl, and / or one acryloxy and / or one methacryloxy group, preferably the alkylene is -CH2-.

5. The curable composition according to any one of the preceding claims, wherein the polymerizable composition comprises 20 to 60 weight% of the first polymerizable component, preferably 40 weight%, with the weight percentage (weight%) based on the total weight of the polymerizable composition.

6. The curable composition according to any one of the preceding claims, wherein the polymerizable composition comprises 20 to 60 weight% of the second polymerizable component, preferably 60 weight%, with the weight percentage (weight%) based on the total weight of the polymerizable composition.

7. The curable composition according to any one of the preceding claims, wherein the polymerizable composition comprises 0.1 to 20 weight%, preferably 4 to 20 weight% of the (meth)acrylate component of formula (II), based of the total weight of the polymerizable composition.

8. The curable composition according to any one of the preceding claims, wherein the polymerizable composition further comprises:- at least one aliphatic (meth)acrylate of formula (III):Wherein,R17 is an alkylene, an alkoxylene, an alkyleneoxy, a poly(alkylene), a poly(alkoxylene) or a poly(alkyleneoxy), wherein the alkylene, the alkoxylene, the alkyleneoxy are linear or branched, saturated and having 1 to 20 carbon atoms, preferably 2 to 15 atoms and wherein the alkylene, the alkoxylene, the alkyleneoxy, the poly(alkylene), the poly(alkoxylene) or the poly(alkyleneoxy) is optionally substituted for example by at leastone hydroxyl or a linear or branched saturated alkyl, at least one hydroxyl, at least one acryloxy and / or at least one methacryloxy group;R18, R19, R20, R21 , R22 and R23, identical or different, are independently a hydrogen or a linear or branched saturated alkyl having 1 to 4 carbon atoms, preferably independently a hydrogen or -CH3; or- at least one aliphatic (meth)acrylate of formula (IV):Wherein,R24 is an alkyl, an alkoxyl, an alkyleneoxy, a poly(alkyl), a poly(alkoxy) or a poly(alkyleneoxy), wherein the alkyl, the alkoxy, the alkyleneoxy are linear or branched, saturated and having 1 to 20 carbon atoms, preferably 2 to 15 atoms and wherein the alkyl, the alkoxy, the alkyleneoxy, the poly(alkyl), the poly(alkoxy) or the poly(alkyleneoxy) is optionally substituted for example by at least one hydroxyl or a linear or branched saturated alkyl and / or at least one hydroxyl;R25, R26 and R27, identical or different, are independently a hydrogen or a linear or branched saturated alkyl having 1 to 4 carbon atoms, preferably independently a hydrogen or -CH3; or- at least one aliphatic (meth)acrylate of formula (III) and at least one aliphatic (meth)acrylate of formula (IV).

9. The curable composition according to any one of the preceding claims, wherein said curable composition has a viscosity equal to or less than 1200 cP at 25°C, preferably equal to or less than 1000 cP at 25°C.

10. An optical material obtained by the curing of the curable composition comprising at least- one photoinitiator and- a polymerizable composition containing at least a mixture of:- 20 to 80 weight% of a first polymerizable component,- 20 to 80 weight% of a second polymerizable component, with the weight percentage (weight%) based on the total weight of the polymerizable composition and, wherein,• The first polymerizable component is an aliphatic urethane (meth)acrylate oligomer,• The second polymerizable component is of formula (I):WhereinRi is a non-aromatic carbocycle or non-aromatic heterocycle wherein the cycle comprising 3 to 20 atoms and is optionally substituted by at least one linear or branched saturated alkyl having 1 to 10 carbon atoms and / or at least one acryloxy and / or one methacryloxy group;R2 and R3, identical or different, are independently an alkylene, an alkoxylene, an alkyleneoxy, a poly(alkylene) or a poly(alkoxylene) or a poly(alkyleneoxy), wherein the alkylene and the alkoxylene and the alkylenoxy are linear or branched, saturated and having 1 to 10 carbon atoms and wherein the alkylene, the alkoxylene, the alkylenoxy, the poly(alkylene), the poly(alkoxylene) or the poly(alkylenoxy) is optionally substituted, for example by at least one hydroxyl, and / or one acryloxy and / or one methacryloxy group;R4, Rs, Re, R9, R10 and Rn, identical or different, are independently hydrogen or a linear or branched saturated alkyl having 1 to 4 carbon atoms, preferably independently a hydrogen or -CH3; m and p, identical or different, are independently 0 or 1 ; and wherein the polymerizable composition further comprises a (meth) acrylate monomer of formula (II):WhereinR12 is a non-aromatic carbocycle or non-aromatic heterocycle wherein the cycle comprising 3 to 20 atoms and is optionally substituted by at least one linear or branched saturated alkyl having 1 to 10 carbon atoms;R13 is an alkylene, an alkoxylene, an alkyleneoxy, a poly(alkylene) or a poly(alkoxylene) or a poly(alkyleneoxy), wherein the alkylene and the alkoxylene and the alkylenoxy are linear or branched, saturated and having 1 to 10 carbon atoms and wherein the alkylene, the alkoxylene, the alkylenoxy, the poly(alkylene), the poly(alkoxylene) or the poly(alkylenoxy) is optionally substituted, for example by at least one hydroxyl, and / or one acryloxy and / or one methacryloxy group;RM, RIS and Rie, identical or different, are independently hydrogen or a linear or branched saturated alkyl having 1 to 4 carbon atoms, preferably independently a hydrogen or -CH3; n is 0 or 1 , wherein when n=0 the acrylate group is directly bonded to R12 and when n=1 the acrylate group is bonded to R13.

11. The optical material according to claim 10, defined as having at least one of the following characteristics:- a refractive index at 550 nm of about 1 .5 at 25°C;- an Abbe number (Ve) of higher or equal to 38 when it is measured using the green line (e) of a mercury lamp at A=546.1 nm;- a Yellowness index (Yi) of lower than 4, more preferably equal or lower than 1 .5;- a relative light transmission factor in the visible spectrum (Tv) equal to or higher than 90% when the optical material has 2 mm thickness;- a storage modulus (E’) at 25°C equal to or greater than 2.2 GPa and equal to or less than 5 GPa;- a storage modulus (E’) at 100°C equal to or greater than 100 MPa, preferably equal to or greater than 400 MPa;- a glass transition temperature (Tg) higher than or equal to 80°C, preferably higher than or equal to 90°C, more preferably higher than 100°C;- a coefficient of linear thermal expansion (CET) equal to or less than about 120 pm / (m.°C), more preferably equal to or less than about 80 pm / (m.°C);- a water uptake after 24h equal to or less than 1 weight%, based on the total weight of the optical material;- a water uptake after 2 months equal to or less than 2 weight%, based on the total weight of the optical material.

12. A method for the manufacturing of an optical element, said method comprising the photopolymerization of the curable composition comprising at least- one photoinitiator and- a polymerizable composition containing at least a mixture of:- 20 to 80 weight% of a first polymerizable component,- 20 to 80 weight% of a second polymerizable component, with the weight percentage (weight%) based on the total weight of the polymerizable composition and, wherein,• The first polymerizable component is an aliphatic urethane (meth)acrylate oligomer,• The second polymerizable component is of formula (I):WhereinRi is a non-aromatic carbocycle or non-aromatic heterocycle wherein the cycle comprising3 to 20 atoms and is optionally substituted by at least one linear or branched saturatedalkyl having 1 to 10 carbon atoms and / or at least one acryloxy and / or one methacryloxy group;R2 and R3, identical or different, are independently an alkylene, an alkoxylene, an alkyleneoxy, a poly(alkylene) or a poly(alkoxylene) or a poly(alkyleneoxy), wherein the alkylene and the alkoxylene and the alkylenoxy are linear or branched, saturated and having 1 to 10 carbon atoms and wherein the alkylene, the alkoxylene, the alkylenoxy, the poly(alkylene), the poly(alkoxylene) or the poly(alkylenoxy) is optionally substituted, for example by at least one hydroxyl, and / or one acryloxy and / or one methacryloxy group;R4, Rs, Re, R9, R10 and Rn, identical or different, are independently hydrogen or a linear or branched saturated alkyl having 1 to 4 carbon atoms, preferably independently a hydrogen or -CH3; m and p, identical or different, are independently 0 or 1 , and wherein the polymerizable composition further comprises a (meth) acrylate monomer of formula (II):WhereinR12 is a non-aromatic carbocycle or non-aromatic heterocycle wherein the cycle comprising 3 to 20 atoms and is optionally substituted by at least one linear or branched saturated alkyl having 1 to 10 carbon atoms;R13 is an alkylene, an alkoxylene, an alkyleneoxy, a poly(alkylene) or a poly(alkoxylene) or a poly(alkyleneoxy), wherein the alkylene and the alkoxylene and the alkylenoxy are linear or branched, saturated and having 1 to 10 carbon atoms and wherein the alkylene, the alkoxylene, the alkylenoxy, the poly(alkylene), the poly(alkoxylene) or the poly(alkylenoxy) is optionally substituted, for example by at least one hydroxyl, and / or one acryloxy and / or one methacryloxy group;R14, R15 and R16, identical or different, are independently hydrogen or a linear or branched saturated alkyl having 1 to 4 carbon atoms, preferably independently a hydrogen or -CHs;n is 0 or 1 , wherein when n=0 the acrylate group is directly bonded to R12 and when n=1 the acrylate group is bonded to R13; said method preferably comprising an additive manufacturing process, more preferably a vat-photopolymerization three-dimensional (3D) printing.

13. An optical element obtained according to the method comprising the photopolymerization of the curable composition, said curable composition comprising at least- one photoinitiator and- a polymerizable composition containing at least a mixture of:- 20 to 80 weight% of a first polymerizable component,- 20 to 80 weight% of a second polymerizable component, with the weight percentage (weight%) based on the total weight of the polymerizable composition and, wherein,• The first polymerizable component is an aliphatic urethane (meth)acrylate oligomer,• The second polymerizable component is of formula (I):WhereinR1 is a non-aromatic carbocycle or non-aromatic heterocycle wherein the cycle comprising 3 to 20 atoms and is optionally substituted by at least one linear or branched saturated alkyl having 1 to 10 carbon atoms and / or at least one acryloxy and / or one methacryloxy group;R2 and R3, identical or different, are independently an alkylene, an alkoxylene, an alkyleneoxy, a poly(alkylene) or a poly(alkoxylene) or a poly(alkyleneoxy), wherein thealkylene and the alkoxylene and the alkylenoxy are linear or branched, saturated and having 1 to 10 carbon atoms and wherein the alkylene, the alkoxylene, the alkylenoxy, the poly(alkylene), the poly(alkoxylene) or the poly(alkylenoxy) is optionally substituted, for example by at least one hydroxyl, and / or one acryloxy and / or one methacryloxy group;R4, Rs, Re, R9, R10 and Rn, identical or different, are independently hydrogen or a linear or branched saturated alkyl having 1 to 4 carbon atoms, preferably independently a hydrogen or -CH3; m and p, identical or different, are independently 0 or 1 ; and wherein the polymerizable composition further comprises a (meth) acrylate monomer of formula (II):WhereinR12 is a non-aromatic carbocycle or non-aromatic heterocycle wherein the cycle comprising 3 to 20 atoms and is optionally substituted by at least one linear or branched saturated alkyl having 1 to 10 carbon atoms;R13 is an alkylene, an alkoxylene, an alkyleneoxy, a poly(alkylene) or a poly(alkoxylene) or a poly(alkyleneoxy), wherein the alkylene and the alkoxylene and the alkylenoxy are linear or branched, saturated and having 1 to 10 carbon atoms and wherein the alkylene, the alkoxylene, the alkylenoxy, the poly(alkylene), the poly(alkoxylene) or the poly(alkylenoxy) is optionally substituted, for example by at least one hydroxyl, and / or one acryloxy and / or one methacryloxy group;R14, R15 and R16, identical or different, are independently hydrogen or a linear or branched saturated alkyl having 1 to 4 carbon atoms, preferably independently a hydrogen or -CHs; n is 0 or 1 , wherein when n=0 the acrylate group is directly bonded to R12 and when n=1 the acrylate group is bonded to R13; wherein the optical element is preferably an ophthalmic element.

14. An ophthalmic lens comprising the ophthalmic element obtained according to the method comprising the photopolymerization of the curable composition, said curable composition comprising at least- one photoinitiator and- a polymerizable composition containing at least a mixture of:- 20 to 80 weight% of a first polymerizable component,- 20 to 80 weight% of a second polymerizable component, with the weight percentage (weight%) based on the total weight of the polymerizable composition and, wherein,• The first polymerizable component is an aliphatic urethane (meth)acrylate oligomer,• The second polymerizable component is of formula (I):WhereinRi is a non-aromatic carbocycle or non-aromatic heterocycle wherein the cycle comprising 3 to 20 atoms and is optionally substituted by at least one linear or branched saturated alkyl having 1 to 10 carbon atoms and / or at least one acryloxy and / or one methacryloxy group;R2 and R3, identical or different, are independently an alkylene, an alkoxylene, an alkyleneoxy, a poly(alkylene) or a poly(alkoxylene) or a poly(alkyleneoxy), wherein the alkylene and the alkoxylene and the alkylenoxy are linear or branched, saturated and having 1 to 10 carbon atoms and wherein the alkylene, the alkoxylene, the alkylenoxy, the poly(alkylene), the poly(alkoxylene) or the poly(alkylenoxy) is optionally substituted, for example by at least one hydroxyl, and / or one acryloxy and / or one methacryloxy group;R4, Rs, Re, R9, R10 and Rn, identical or different, are independently hydrogen or a linear or branched saturated alkyl having 1 to 4 carbon atoms, preferably independently a hydrogen or -CH3; m and p, identical or different, are independently 0 or 1 ; and wherein the polymerizable composition further comprises a (meth) acrylate monomer of formula (II):WhereinR12 is a non-aromatic carbocycle or non-aromatic heterocycle wherein the cycle comprising 3 to 20 atoms and is optionally substituted by at least one linear or branched saturated alkyl having 1 to 10 carbon atoms;R13 is an alkylene, an alkoxylene, an alkyleneoxy, a poly(alkylene) or a poly(alkoxylene) or a poly(alkyleneoxy), wherein the alkylene and the alkoxylene and the alkylenoxy are linear or branched, saturated and having 1 to 10 carbon atoms and wherein the alkylene, the alkoxylene, the alkylenoxy, the poly(alkylene), the poly(alkoxylene) or the poly(alkylenoxy) is optionally substituted, for example by at least one hydroxyl, and / or one acryloxy and / or one methacryloxy group;RM, RIS and Rie, identical or different, are independently hydrogen or a linear or branched saturated alkyl having 1 to 4 carbon atoms, preferably independently a hydrogen or -CHs; n is 0 or 1 , wherein when n=0 the acrylate group is directly bonded to R12 and when n=1 the acrylate group is bonded to R13.

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