Photocurable polymer, photocurable polymer composition and photolithography process comprising the same

Abstract

The present invention relates to a polymer formulation for three-dimensional (3D) printing of articles by stereolithography, the formulation comprising a functionalized polymer. The present invention further relates to a lithographic method for forming a 3D object incorporating the aforementioned polymer formulation.

Description

[0001] Related Applications

[0002] This application claims priority to U.S. Provisional Application No. 62 / 743,756, filed on October 10, 2018, the entire contents of which are incorporated by reference into this application for all purposes. Technical Field

[0003] The present invention relates to a polymer formulation for three-dimensional (3D) printing of articles by stereolithography, the formulation comprising a functionalized polymer. The present invention further relates to a lithographic method for forming a 3D object incorporating the aforementioned polymer formulation. Background Art

[0004] Recently, photolithography has found favor in the photoprocessing of 3D articles from polymeric materials due to its relative speed and simplicity. Typically, photolithography involves the use of light, such as UV irradiation, to locally cure a polymerizable formulation at specific locations. This localized curing allows the processing of three-dimensional articles.

[0005] Photolithographic processes typically use polymerizable formulations that are liquids in order to obtain parts with good resolution. Polymerizable formulations that are liquids at room temperature are easier to use in printing processes, but they typically produce articles with mediocre mechanical properties and thermal stability.

[0006] Certain polymers used in photolithography processes exhibit a good profile of mechanical properties. These polymers need to melt above their melting temperatures to be used in liquid polymerizable formulations. One of the challenges in identifying valuable polymers is that they need to remain thermally stable at the polymer melting temperature and be reactive during the printing process when irradiating a layer of the polymerizable formulation.

[0007] Another challenge for valuable polymerizable formulations for use in photolithographic processes is that they must be able to produce 3D articles that exhibit good mechanical properties after photoprocessing and that substantially retain these mechanical properties after exposure to elevated temperatures (eg, above 150°C).

[0008] The polymerizable formulations of the present invention provide a very suitable solution for high temperature 3D printing processes. Summary of the invention

[0009] The present invention relates to a polymer formulation (F) comprising a polymer (P) selected from poly(aryl ether sulfone) (PAES) and polyetherimide (PEI) polymers, wherein the polymer (P) comprises at least one end group having the formula (M1) or (M2):

[0010]

[0011] in

[0012] -R is H or CH 3 ,

[0013] -X is a bond or (CH 2 ) n , where n ranges from 1 to 20, and

[0014] wherein the polymer (P) has a number average molecular weight (Mn) of less than 40,000 g / mol, less than 35,000 g / mol, less than 30,000 g / mol, less than 25,000 g / mol, less than 20,000 g / mol, less than 15,000 g / mol or less than 10,000 g / mol as determined by gel permeation chromatography (GPC) using dichloromethane as mobile phase and polystyrene standards.

[0015] This polymer formulation (F) can be used, for example, in photoprocessing. In particular, the formulation (F) of the present invention can be incorporated into a photolithography process, in which light is used to cure these functionalized polymers. The formulation (F) of the present invention can be converted into a liquid state at a temperature below or above the Tg of the polymer (P) without significant changes, and then cured by irradiation with UV light, thereby producing a high thermal property material with high Tg, high mechanical properties and high thermal stability. The formulation (F) of the present invention can be effectively used in 3D printing lithography processes.

[0016] The present invention also relates to a method for manufacturing a three-dimensional (3D) article using an additive manufacturing system, the method comprising:

[0017] - providing a polymer formulation (F) according to the invention, and

[0018] - Printing a layer of the 3D article from the polymer formulation (F).

[0019] According to another embodiment of the invention, the printing step comprises irradiating the polymer formulation (F) with UV light. The UV light may be, for example, a laser.

[0020] The present invention also relates to a 3D article obtainable at least in part by the above method, and to the use of the polymer formulation (F) for the production of a 3D object by stereolithography (SLA). BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic diagram of the 3D object to be printed.

[0022] Figure 2 is a picture of an object printed by comparative formulation 1.

[0023] Figure 3is a picture of an object printed by formulation 2 of the present invention. DETAILED DESCRIPTION

[0024] The present invention relates to a polymer formulation (F) comprising at least one polymer (P) selected from the group consisting of poly(aryl ether sulfone) (PAES) polymers and polyetherimide (PEI) polymers, wherein the polymer (P) has been functionalized. More precisely, the polymer (P) comprises at least one end group of formula (M1) or (M2):

[0025]

[0026] in

[0027] -R is H or CH 3 ,

[0028] -X is a bond or (CH 2 ) n , wherein n ranges from 1 to 20, such as from 1 to 10 or from 1 to 8.

[0029] According to the present invention, the number average molecular weight (Mn) of polymer (P) is less than 40,000 g / mol, less than 35,000 g / mol, less than 30,000 g / mol, less than 25,000 g / mol, less than 20,000 g / mol, less than 15,000 g / mol or less than 10,000 g / mol, as determined by gel permeation chromatography (GPC) using dichloromethane as mobile phase and polystyrene standards. Preferably, the number average molecular weight (Mn) of polymer (P) is less than 20,000 g / mol.

[0030] Formulations (F) comprising the functionalized polymers (P) of the invention can be used in photofabrication processes. In particular, the polymers (P) and polymer formulations (F) of the invention can be incorporated into photolithographic processes, wherein light is used to cure the functionalized polymers.

[0031] The formulation (F) of the present invention further comprises:

[0032] - at least one solvent,

[0033] - at least one photoinitiator, and

[0034] - At least one blocking agent.

[0035] The formulations (F) according to the invention are preferably liquid, for example at room temperature or above room temperature.

[0036] According to the invention, a photoinitiator is a compound which is added to the formulation in particular in order to convert absorbed light energy, UV or visible light, into chemical energy in the form of initiating species, for example free radicals or cations.

[0037] According to the present invention, a retarder is a compound added to scavenge unused free radicals generated by a photoinitiator or to absorb a portion of the incident UV energy. Such a compound can improve the dimensional accuracy of the manufactured part.

[0038] The polymer (P) described in the present invention is functionalized with functional groups, which are (meth)acrylic moieties (M1) and / or styrene (M2). The functional groups are introduced as post-polymerization modifications at at least one end of the polymer chain, for example at both ends of the polymer chain, and / or in the side chains of the polymer backbone.

[0039] More precisely, the polymer (P) described in the present invention is functionalized at least at one end of the polymer chain, as "terminal functionalization". The polymer (P) of the present invention can be functionalized at both ends of the polymer chain. The polymer (P) of the present invention can also be functionalized within the polymer backbone, as "internal functionalization". For example, with regard to internal functionalization, one or more repeating units of the polymer (P) that are not located at the end of the polymer chain can be functionalized with a functional group, which is a (meth)acrylic acid moiety.

[0040] The formulation (P) of the invention may comprise more than one polymer (P), for example two of three different polymers (P).

[0041] Poly(arylethersulfone) (PAES)

[0042] According to an embodiment, P is a repeating unit (R) having formula (L) PAES ) of PAES:

[0043]

[0044] - Each R 1 independently selected from the group consisting of halogen, alkyl, alkenyl, alkynyl, aryl, ether, thioether, carboxylic acid, ester, amide, imide, alkali metal or alkaline earth metal sulfonate, alkyl sulfonate, alkali metal or alkaline earth metal phosphonate, alkyl phosphonate, amine and quaternary ammonium;

[0045] - for each aromatic ring, each i is an independently selected integer from 0 to 4;

[0046] -T is selected from the group consisting of: a bond, -CH 2 -;-O-;-SO 2 -;-S-;

[0047] -C(O)-; -C(CH 3 ) 2 -;-C(CF 3 ) 2 -;-C(=CCl 2 )-;-C(CH 3 )(CH 2 CH 2 COOH)-; -N=N-; -R a C=CR b -, where R a and R b each independently of one another is hydrogen or C1-C12-alkyl, C1-C12-alkoxy, or C6-C18-aryl;

[0048] -(CH 2 ) m -and-(CF 2 ) m -, wherein m is an integer from 1 to 6; a linear or branched aliphatic divalent group having up to 6 carbon atoms; and combinations thereof;

[0049] -R is H or CH 3 .

[0050] According to an embodiment, when P is PAES, the polymer (P) of the present invention may comprise:

[0051] - at least a repeating unit (R) of formula (L) PAES ):

[0052]

[0053] and / or

[0054] - at least one terminal group having formula (M):

[0055]

[0056] in:

[0057] - Each R 1 independently selected from the group consisting of halogen, alkyl, alkenyl, alkynyl, aryl, ether, thioether, carboxylic acid, ester, amide, imide, alkali metal or alkaline earth metal sulfonate, alkyl sulfonate, alkali metal or alkaline earth metal phosphonate, alkyl phosphonate, amine and quaternary ammonium;

[0058] - for each aromatic ring, each i is an independently selected integer from 0 to 4;

[0059] -T is selected from the group consisting of: a bond, -CH 2 -;-O-;-SO 2-;-S-;

[0060] -C(O)-; -C(CH 3 ) 2 -;-C(CF 3 ) 2 -;-C(=CCl 2 )-;-C(CH 3 )(CH 2 CH 2 COOH)-; -N=N-; -R a C=CR b -, where R a and R b each independently of one another is hydrogen or C1-C12-alkyl, C1-C12-alkoxy, or C6-C18-aryl;

[0061] -(CH 2 ) m -and-(CF 2 ) m -, wherein m is an integer from 1 to 6; a linear or branched aliphatic divalent group having up to 6 carbon atoms; and combinations thereof;

[0062] -R is H or CH 3 .

[0063] According to another embodiment, the repeating unit (R PAES ) is according to formula (L'):

[0064]

[0065] Where R 1 and i are as described above.

[0066] According to an embodiment, one or more end groups of the polymer (P) are according to formula (M'):

[0067]

[0068] Where R 1 , R and i are as described above.

[0069] According to an embodiment, for each R 1 , i is zero. In other words, according to this embodiment,

[0070] -Repeating unit (R PAES ) is a unit having formula (L"):

[0071]

[0072] - one or more end groups of the polymer (P) are according to formula (M"):

[0073]

[0074] Wherein T is as described above.

[0075] According to an embodiment, P is a PAES having at least 50 mol.% (based on the total moles in the polymer) of repeating units of formula (L), (L') or (L"), and comprises at least one end group of formula (M), (M') or (M").

[0076] According to an embodiment of the present invention, at least 60 mol.%, at least 70 mol.%, at least 80 mol.%, at least 90 mol.%, at least 95 mol.%, at least 99 mol.% (based on the total moles in the polymer) or all of the repeating units in PAES are repeating units (R) having formula (L), (L') or (L") PAES ), and comprises at least one terminal group having the formula (M), (M') or (M").

[0077] According to an embodiment of the present invention, P is PAES, wherein T is selected from the group consisting of: a bond, -SO 2 - and -C(CH 3 ) 2 -.

[0078] According to another embodiment of the present invention, P is PAES having at least 50 mol.% (based on the total moles in the polymer) of repeating units selected from the group consisting of:

[0079]

[0080]

[0081] and / or

[0082]

[0083] Where R 1 and i are as described above.

[0084] According to this embodiment, at least 60 mol.%, at least 70 mol.%, at least 80 mol.%, at least 90 mol.%, at least 95 mol.%, at least 99 mol.% (based on the total moles in the polymer) or all of the repeating units in the PAES are repeating units (R) of formula (LA), formula (LB) and / or formula (LC). PAES ).

[0085] According to an embodiment, P is PAES, wherein T is a bond. In other words, P is a functionalized poly(biphenyl ether sulfone) (PPSU).

[0086] According to an embodiment, P is a PPSU comprising:

[0087] - at least 50 mol.% of the repeating units are repeating units of formula (LA) (R PPSU ):

[0088]

[0089] (mol. % is based on the total moles in the polymer),

[0090] Where R 1 and i is as above, and

[0091] - at least one terminal group having the formula (M1) or (M2):

[0092]

[0093] in

[0094] -R is H or CH 3 ,and

[0095] -X is a bond or (CH 2 ) n , wherein n varies from 1 to 20, such as 1 to 10, preferably equal to 1 or 2.

[0096] The PPSU polymer of the present invention can be a homopolymer or a copolymer. If it is a copolymer, it can be a random copolymer, an alternating copolymer or a block copolymer.

[0097] According to an embodiment of the present invention, at least 60 mol.%, at least 70 mol.%, at least 80 mol.%, at least 90 mol.%, at least 95 mol.%, at least 99 mol.% or all of the repeating units in the PPSU are repeating units (R PPSU ).

[0098] When the poly(biphenyl ether sulfone) (PPSU) is a copolymer, it may be composed of repeating units (R PPSU ) different repeating units (R* PPSU ), such as the above-mentioned repeating units of formula (LB) and / or formula (LC), and / or repeating units of formula (LD):

[0099]

[0100] Where R 1and i are as described above.

[0101] Poly(biphenyl ether sulfone) (PPSU) can be prepared by any method known in the art.

[0102] For example, it can be

[0103] It is formed by condensation of 4,4'-dihydroxybiphenyl (bisphenol) and 4,4'-dichlorodiphenyl sulfone in the presence of a base. The reaction of the monomer units proceeds by nucleophilic aromatic substitution with simultaneous elimination of a hydrogen halide unit as a leaving group. However, it should be noted that the structure of the resulting poly(biphenyl ether sulfone) does not depend on the nature of the leaving group. PPSU is then modified after polymerization to introduce a functional group at at least one end of the polymer chain. The functional group is of the formula CH 2 =CH-CH 2 -(CH 2 ) n — α-olefin, wherein n varies between 1 and 10. α-olefin functional groups can also be introduced at both ends of the polymer chain, and / or in the side chains of the polymer backbone.

[0104] According to an embodiment, P is PAES, wherein T is -C(CH 3 ) 2 -. In other words, P is functionalized polysulfone (PSU).

[0105] According to an embodiment, P is a PSU comprising:

[0106] - at least 50 mol.% of the repeating units are repeating units (R) of formula (LB) PSU ):

[0107]

[0108] (mol. % is based on the total moles in the polymer),

[0109] Where R 1 and i is as above, and

[0110] - at least one terminal group having the formula (M1) or (M2):

[0111]

[0112] in

[0113] -R is H or CH 3 ,and

[0114] -X is a bond or (CH 2 )n, wherein n varies from 1 to 20, for example 1 to 10, preferably equal to 1 or 2.

[0115] Therefore, the PSU polymer of the present invention can be a homopolymer or a copolymer. If it is a copolymer, it can be a random copolymer, an alternating copolymer or a block copolymer.

[0116] According to an embodiment of the present invention, at least 60 mol.%, at least 70 mol.%, at least 80 mol.%, at least 90 mol.%, at least 95 mol.%, at least 99 mol.% or all of the repeating units in PSU are repeating units (R) having formula (LB) PSU ).

[0117] When polysulfone (PSU) is a copolymer, it may be composed of different repeating units (R PSU ) repeating unit (R* PSU ), such as repeating units having formula (LA), (LC) and / or (LD), all as described above.

[0118] According to an embodiment, P is PAES, wherein T is -SO 2 -. In other words, P is functionalized polyethersulfone (PES).

[0119] According to an embodiment, P is a PES comprising:

[0120] - at least 50 mol.% of the repeating units are repeating units (R) of formula (LC) PES ):

[0121]

[0122] (mol. % is based on the total moles in the polymer),

[0123] Where R 1 and i is as above, and

[0124] - at least one terminal group having the formula (M1) or (M2):

[0125]

[0126] in

[0127] -R is H or CH 3 ,and

[0128] -X is a bond or (CH 2 )n, wherein n varies from 1 to 20, for example 1 to 10, preferably equal to 1 or 2.

[0129] Therefore, the PES polymer of the present invention can be a homopolymer or a copolymer. If it is a copolymer, it can be a random copolymer, an alternating copolymer or a block copolymer.

[0130] According to an embodiment of the present invention, at least 60 mol.%, at least 70 mol.%, at least 80 mol.%, at least 90 mol.%, at least 95 mol.%, at least 99 mol.% or all of the repeating units in PES are repeating units (R) having formula (LC) PES ).

[0131] When polyethersulfone (PES) is a copolymer, it may be composed of PESU ) different repeating units (R* PESU ), such as repeating units having formula (LA), (LB) and / or (LD), all as described above.

[0132] Poly(etherimide) (PEI)

[0133] According to an embodiment, P is a repeating unit (R PEI ) of PEI, the repeating unit comprising at least one aromatic ring, at least one imide group (as is and / or in its amide acid form) and at least one ether group. PEI ) may optionally further comprise at least one amide group which is not comprised in the amic acid form of an imide group.

[0134] According to an embodiment, the repeating unit (R PEI ) is selected from the group consisting of the following formulae: (I), (II), (III), (IV), (V) and mixtures thereof:

[0135]

[0136]

[0137] in

[0138] -Ar is a tetravalent aromatic moiety and is selected from the group consisting of substituted or unsubstituted, saturated, unsaturated or aromatic monocyclic and polycyclic groups having 5 to 50 carbon atoms;

[0139] -Ar' is a trivalent aromatic moiety and is selected from the group consisting of substituted, unsubstituted, saturated, unsaturated aromatic monocyclic and aromatic polycyclic groups having from 5 to 50 C atoms; and

[0140] -R is selected from the group consisting of substituted and unsubstituted divalent organic groups, for example, selected from the group consisting of:

[0141] (a) an aromatic hydrocarbon group having 6 to 20 carbon atoms and a halogenated derivative thereof;

[0142] (b) a straight chain or branched chain alkylene group having 2 to 20 carbon atoms;

[0143] (c) a cycloalkylene group having 3 to 20 carbon atoms, and

[0144] (d) a divalent group having the formula (VI):

[0145]

[0146] in

[0147] -Y is selected from the group consisting of: an alkylene group having 1 to 6 carbon atoms, such as -C(CH 3 ) 2 and -C n H 2n -(n is an integer from 1 to 6); a perfluoroalkylene group having 1 to 6 carbon atoms, such as -C(CF 3 ) 2 and -C n F 2n -

[0148] (n is an integer from 1 to 6); a cycloalkylene group having 4 to 8 carbon atoms; an alkylene group having 1 to 6 carbon atoms; a cycloalkylene group having 4 to 8 carbon atoms; -O-; -S-; -C(O)-; -SO 2 -;-SO-, and

[0149] -R" is selected from the group consisting of hydrogen, halogen, alkyl, alkenyl, alkynyl, aryl, ether, thioether, carboxylic acid, ester, amide, imide, alkali metal sulfonate, alkaline earth metal sulfonate, alkyl sulfonate, alkali metal phosphonate, alkaline earth metal phosphonate, alkyl phosphonate, amine and quaternary ammonium, and

[0150] - for each R", i is independently zero or an integer ranging from 1 to 4,

[0151] The prerequisite is that at least one of Ar, Ar' and R contains at least one ether group and the ether group is present in the polymer chain backbone.

[0152] According to an embodiment, Ar is selected from the group consisting of:

[0153]

[0154] in

[0155] X is a divalent moiety having a divalent bond at the 3,3', 3,4', 4,3" or 4,4' position and is selected from the group consisting of an alkylene group having 1 to 6 carbon atoms, such as -C(CH 3 ) 2 and -Cn H 2n -(n is an integer from 1 to 6); a perfluoroalkylene group having 1 to 6 carbon atoms,

[0156] For example -C(CF 3 ) 2 and -C n F 2n -(n is an integer from 1 to 6); a cycloalkylene group having 4 to 8 carbon atoms; an alkylene group having 1 to 6 carbon atoms; a cycloalkylene group having 4 to 8 carbon atoms; -O-; -S-; -C(O)-;

[0157] -SO 2 -;-SO-;

[0158] Alternatively X is a group of formula -O-Ar"-O-, wherein Ar" is an aromatic moiety selected from the group consisting of substituted or unsubstituted, saturated, unsaturated or aromatic monocyclic and polycyclic groups having 5 to 50 carbon atoms.

[0159] According to an embodiment, Ar' is selected from the group consisting of:

[0160]

[0161] in

[0162] X is a divalent moiety having a divalent bond at the 3,3', 3,4', 4,3" or 4,4' position and is selected from the group consisting of an alkylene group having 1 to 6 carbon atoms, such as -C(CH 3 ) 2 and -C n H 2n -(n is an integer from 1 to 6); a perfluoroalkylene group having 1 to 6 carbon atoms,

[0163] For example -C(CF 3 ) 2 and -C n F 2n -(n is an integer from 1 to 6); a cycloalkylene group having 4 to 8 carbon atoms; an alkylene group having 1 to 6 carbon atoms; a cycloalkylene group having 4 to 8 carbon atoms; -O-; -S-; -C(O)-;

[0164] -SO 2 -;-SO-;

[0165] Alternatively X is a group of formula -O-Ar"-O-, wherein Ar" is an aromatic moiety selected from the group consisting of substituted or unsubstituted, saturated, unsaturated or aromatic monocyclic and polycyclic groups having 5 to 50 carbon atoms.

[0166] According to embodiments of the present disclosure, at least 50 mol.%, at least 60 mol.%, at least 70 mol.%, at least 80 mol.%, at least 90 mol.%, at least 95 mol.%, at least 99 mol.%, or all of the repeating units in PEI are repeating units (R) having formula (I), (II), (III), (IV), (V) as defined above. PEI ) and / or mixtures thereof.

[0167] According to an embodiment, P is PEI having at least 50 mol.% of repeating units (R) of formula (VII) based on the total moles in the polymer. PEI ):

[0168]

[0169] in

[0170] -R is selected from the group consisting of substituted and unsubstituted divalent organic groups, for example, selected from the group consisting of:

[0171] (a) an aromatic hydrocarbon group having 6 to 20 carbon atoms and a halogenated derivative thereof;

[0172] (b) a straight chain or branched chain alkylene group having 2 to 20 carbon atoms;

[0173] (c) a cycloalkylene group having 3 to 20 carbon atoms, and

[0174] (d) a divalent group having the formula (VI):

[0175]

[0176] in

[0177] -Y is selected from the group consisting of: an alkylene group having 1 to 6 carbon atoms, such as -C(CH 3 ) 2 and -C n H 2n -(n is an integer from 1 to 6); a perfluoroalkylene group having 1 to 6 carbon atoms,

[0178] For example -C(CF 3 ) 2 and -C n F 2n -

[0179] (n is an integer from 1 to 6); a cycloalkylene group having 4 to 8 carbon atoms; an alkylene group having 1 to 6 carbon atoms; a cycloalkylene group having 4 to 8 carbon atoms; -O-; -S-; -C(O)-; -SO 2-;-SO-, and

[0180] -R" is selected from the group consisting of hydrogen, halogen, alkyl, alkenyl, alkynyl, aryl, ether, thioether, carboxylic acid, ester, amide, imide, alkali metal sulfonate, alkaline earth metal sulfonate, alkyl sulfonate, alkali metal phosphonate, alkaline earth metal phosphonate, alkyl phosphonate, amine and quaternary ammonium, and

[0181] - for each R", i is independently zero or an integer ranging from 1 to 4,

[0182] The prerequisite is that at least one of Ar, Ar' and R contains at least one ether group and the ether group is present in the polymer chain backbone.

[0183] -T can be

[0184] -O- or -O-Ar”-O-

[0185] wherein the divalent bond of the -O- or -O-Ar"-O- group is at the 3,3', 3,4', 4,3', or 4,4' position,

[0186] wherein Ar" is an aromatic moiety selected from the group consisting of substituted or unsubstituted, saturated, unsaturated or aromatic monocyclic and polycyclic groups having 5 to 50 carbon atoms, such as substituted or unsubstituted phenylene, substituted or unsubstituted biphenyl, substituted or unsubstituted naphthyl, or a moiety comprising two substituted or unsubstituted phenylene groups.

[0187] According to embodiments of the present disclosure, Ar" has the general formula (VI) as detailed above; for example, Ar" has the formula (XIX):

[0188]

[0189] The polyetherimide (PEI) of the present invention can be prepared by any of the methods known to those skilled in the art, including making a polyetherimide having the formula H 2 NR-NH 2 The diamino compound of formula (XX) (wherein R is as defined above) is reacted with any aromatic bis(ether anhydride) having formula (XXI) (wherein T is as defined above):

[0190]

[0191] Typically, the preparation can be carried out in a solvent (eg, o-dichlorobenzene, m-cresol / toluene, N,N-dimethylacetamide) at a temperature ranging from 20°C to 250°C.

[0192] Alternatively, the polyetherimides can be prepared by melt polymerizing any dianhydride having formula (XXI) with any diamino compound having formula (XX) while heating the mixture of these ingredients at elevated temperature while simultaneously mixing with each other.

[0193] Aromatic bis(ether anhydrides) having formula (XXI) include, for example:

[0194] 2,2-Bis[4-(2,3-dicarboxyphenoxy)phenyl]propane dianhydride; 4,4'-bis(2,3-dicarboxyphenoxy)diphenyl ether dianhydride; 1,3-bis(2,3-dicarboxyphenoxy)phthalic anhydride; 4,4'-bis(2,3-dicarboxyphenoxy)diphenyl sulfide dianhydride; 1,4-bis(2,3-dicarboxyphenoxy)phthalic anhydride; 4,4'-bis(2,3-dicarboxyphenoxy)benzophenone dianhydride; 4,4'-bis(2,3-dicarboxyphenoxy)diphenyl sulfone dianhydride; 2,2-bis[4(3,4-dicarboxyphenoxy)phenyl]propane dianhydride; 4,4'-bis(2,3-dicarboxyphenoxy)diphenyl ether dianhydride; 1,3-bis(2,3-dicarboxyphenoxy)phthalic anhydride; 4,4'-bis(2,3-dicarboxyphenoxy)diphenyl sulfide dianhydride; 1,4-bis(2,3-dicarboxyphenoxy)phthalic anhydride; 4,4'-bis(2,3-dicarboxyphenoxy)benzophenone dianhydride; 4,4'-bis(2,3-dicarboxyphenoxy)diphenyl sulfone dianhydride;

[0013] The invention further comprises the following: 1,2-bis(3,4-dicarboxyphenoxy)phenyl]propane dianhydride; 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl ether dianhydride; 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl sulfide dianhydride; 1,3-bis(3,4-dicarboxyphenoxy)phthalic dianhydride; 1,4-bis(3,4-dicarboxyphenoxy)phthalic dianhydride; 4,4'-bis(3,4-dicarboxyphenoxy)benzophenone dianhydride; 4-(2,3-dicarboxyphenoxy)-4'-(3,4-dicarboxyphenoxy)diphenyl-2,2-propane dianhydride; and mixtures of such dianhydrides.

[0195] The organic diamine having formula (XX) is selected from the group consisting of meta-phenylenediamine, para-phenylenediamine, 2,2-bis(p-aminophenyl)propane, 4,4'-diaminodiphenyl-methane, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ether, 1,5-diaminonaphthalene, 3,3'-dimethylbenzidine, 3,3'-dimethoxybenzidine, and mixtures thereof; preferably, the organic diamine having formula (XX) is selected from the group consisting of meta-phenylenediamine and para-phenylenediamine and mixtures thereof.

[0196] According to an embodiment, P is PEI, which comprises at least 50 mol.% of repeating units (R) having formula (XXIII) or (XXIV) (in the form of imide or their corresponding amide acid) based on the total moles in the polymer. PEI ) and mixtures thereof:

[0197]

[0198]

[0199] In a preferred embodiment of the present invention, at least 50 mol.%, at least 60 mol.%, at least 70 mol.%, at least 80 mol.%, at least 90 mol.%, at least 95 mol.%, at least 99 mol.% or all of the repeating units in PEI are repeating units (R) having formula (XXIII) or (XXIV) (in the form of imide or their corresponding amide acid) PEI ) and mixtures thereof.

[0200] Solvents

[0201] The concentration of the solvent may be between 1 and 80 wt.%, for example between 2 and 75 wt.%, between 5 and 70 wt.%, or between 10 and 65 wt.%, based on the total weight of formulation (F).

[0202] According to an example of the present invention, the solvent is selected from the group consisting of: N-methylpyrrolidone (NMP), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAC), 1,3-dimethyl-2-imidazolidinone, tetrahydrofuran (THF), dimethyl sulfoxide (DMSO) and sulfolane.

[0203] Preferably, the solvent is a dipolar aprotic solvent. Preferably, the solvent is selected from the group consisting of: N-methylpyrrolidone (NMP), dimethylacetamide (DMAc or DMA), N-cyclohexyl-2-pyrrolidone (CHP) and dimethyl sulfoxide (DMSO).

[0204] Photoinitiator

[0205] According to the invention, a photoinitiator is a compound which is added to the formulation in particular to convert the absorbed light energy, UV or visible light, into chemical energy in the form of initiating species, such as free radicals or cations. Based on the mechanism of initiating free radical formation, photoinitiators are generally divided into two categories:

[0206] -Type I photoinitiators undergo unimolecular bond scission upon irradiation, generating free radicals,

[0207] -Type II photoinitiators undergo a bimolecular reaction in which the excited state of the photoinitiator interacts with a second molecule (coinitiator) to generate free radicals.

[0208] The concentration of the photoinitiator in formulation (F) may be between 0.05 and 10 wt.%, for example between 0.1 and 5 wt.%, between 0.2 and 4 wt.%, or between 0.5 and 3 wt.%, based on the total weight of formulation (F).

[0209] According to an embodiment of the present invention, the photoinitiator is selected from the group consisting of:

[0210] -Acetophenone

[0211] -Fennel Olein

[0212] -Anthraquinone

[0213] -Anthraquinone-2-sulfonic acid, sodium salt monohydrate

[0214] -(Benzene)tricarbonylchromium

[0215] -Diphenylethanedione

[0216] -Benzoin

[0217] -Benzoin ethyl ether, benzoin isobutyl ether, benzoin methyl ether and benzophenone

[0218] -3,3',4,4'-Benzophenonetetracarboxylic dianhydride

[0219] -4-Benzoylbiphenyl

[0220] -2-Benzyl-2-(dimethylamino)-4'-morpholinobutyrophenone

[0221] -4,4'-Bis(diethylamino)benzophenone

[0222] -4,4'-Bis(dimethylamino)benzophenone

[0223] -Camphorquinone

[0224] -2-Chlorothioxanthene-9-one

[0225] -(Cumene)cyclopentadienyliron(II) hexafluorophosphate

[0226] -Dibenzocycloheptenone

[0227] -2,2-Diethoxyacetophenone

[0228] -4,4'-Dihydroxybenzophenone

[0229] -2,2-Dimethoxy-2-phenylacetophenone

[0230] -4-(Dimethylamino)benzophenone

[0231] -4,4'-Dimethyldiphenylethanedione

[0232] -2,5-Dimethylbenzophenone

[0233] -3,4-Dimethylbenzophenone

[0234] -Diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide, 2-hydroxy-2-methylpropiophenone and blends (e.g. 50 / 50 blends)

[0235] -4'-Ethoxyacetophenone

[0236] -2-Ethylanthraquinone

[0237] -Ferrocene

[0238] -3'-hydroxyacetophenone, 4'-hydroxyacetophenone, 3-hydroxyacetophenone and 4-hydroxyacetophenone

[0239] -1-Hydroxycyclohexyl phenyl ketone

[0240] -2-Hydroxy-2-methylpropiophenone

[0241] -2-methylbenzophenone or 3-methylbenzophenone

[0242] -Methylbenzoyl formate

[0243] -2-Methyl-4'-(methylthio)-2-morpholinopropiophenone

[0244] -Phenanthrenequinone

[0245] -4'-Phenoxyacetophenone

[0246] -phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide

[0247] -Thioxanthen-9-one

[0248] -Triarylsulfonium hexafluoroantimonates, mixed, 50% in propylene carbonate

[0249] -triarylsulfonium hexafluorophosphates, mixed, 50% in propylene carbonate, and

[0250] - mixtures thereof.

[0251] Preferably, the photoinitiator is selected from the group consisting of 2,2-dimethoxy-2-phenylacetophenone (DMPA), diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide.

[0252] Blockers

[0253] According to the present invention, a retardant is a compound that is added to the formulation in order to (i) scavenge a predetermined amount of free radicals formed by the photoinitiator under UV light irradiation, (ii) scavenge unused free radicals that may be present after the UV irradiation source is turned off, and / or (iii) absorb a portion of the energy transferred to the system during UV irradiation.

[0254] The concentration of the retarder in formulation (F) may be between 0.05 and 10 wt.%, for example between 0.1 and 5 wt.%, between 0.2 and 4 wt.%, or between 0.5 and 3 wt.%, based on the total weight of formulation (F).

[0255] According to an embodiment of the present invention, the blocker is selected from the group consisting of:

[0256] -2-Hydroxy-4-methoxybenzophenone (hydroxyphenyl)

[0257] -1-(4-methoxyphenyl)-3-(4-tert-butylphenyl)propane-1,3-dione (Avobenzone)

[0258] -2,2'-(1,4-phenylene)bis(6-sulfo-1H-benzimidazole-4-sulfonate) disodium (phenyl dibenzimidazole tetrasulfonate disodium)

[0259] -2-[4-(Diethylamino)-2-hydroxybenzoyl]benzoic acid hexyl ester (Diethylaminohydroxybenzoyl benzoic acid hexyl ester)

[0260] -Menthyl-anthranilate (menthyl anthranilate)

[0261] -2,2'-[6-(4-methoxyphenyl)-1,3,5-triazine-2,4-diyl]bis{5-[(2-ethylhexyl)oxy]phenol} (bemotrizinol)

[0262] -2,4-Dihydroxybenzophenone

[0263] -2,2',4,4'-Tetrahydroxybenzophenone

[0264] -4-Hydroxy-2-methoxy-5-(oxo-phenylmethyl)benzenesulfonic acid (Sulisophenone)

[0265] -2,2'-dihydroxy-4,4'-dimethoxybenzophenone

[0266] -5-Chloro-2-hydroxybenzophenone

[0267] -(2-Hydroxy-4-methoxyphenyl)-(2-hydroxyphenyl)methanone (dihydroxybenzoate)

[0268] -2,5-Bis(5-tert-butyl-benzoxazol-2-yl)thiophene

[0269] -2,2'-dihydroxy-4,4'-dimethoxybenzophenone-5,5'-disulfonate sodium salt

[0270] -(2-Hydroxy-4-methoxyphenyl)(4-methylphenyl)methanone (Mexitone)

[0271] -(2-Hydroxy-4-octyloxy-phenyl)-phenyl-methanone (octabenzone)

[0272] -2-(1,2,3-benzotriazol-2-yl)-4-methyl-6-[2-methyl-3-(2,2,4,6,6-pentamethyl-3,5-dioxa-2,4,6-trisilanehept-4-yl)propyl]phenol (Dromtriazole trisiloxane)

[0273] -Terephthalidene dicamphor sulfonic acid (Ecamsule)

[0274] -2-Ethylhexyl 2-cyano-3,3-diphenyl-2-acrylate (Octocrylene)

[0275] -Diethylhexyl butyramido triazone (iscotrizinole)

[0276] -2-Ethoxyethyl 3-(4-methoxyphenyl) acrylate (Cinoxamate)

[0277] -4-Methoxycinnamic acid isopentyl ester (amiloate)

[0278] -2,2'-methanediylbis[6-(2H-benzotriazol-2-yl)-4-(2,4,4-trimethylpentan-2-yl)phenol](bisoctylphenoltriazole)

[0279] -2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol

[0280] -2,2'-Methylenebis[6-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol]

[0281] -2-Hydroxy-4-(octyloxy)benzophenone

[0282] -2-ethyl-,2-[4-(4,6-diphenyl-1,3,5-triazin-2-yl)-3-hydroxyphenoxy]ethyl ester

[0283] -2-tert-butyl-6-(5-chloro-2H-benzotriazol-2-yl)-4-methylphenol

[0284] -2-(2-Hydroxy-5-methylphenyl)benzotriazole

[0285] -2,4-Dinitrophenylhydrazine

[0286] -N-(4-ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidine

[0287] -Hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate

[0288] -2-ethyl-2'-ethoxy-oxalanilide, and

[0289] - mixtures thereof.

[0290] Preferably, the retardant is selected from the group consisting of avobenzone and 2,5-bis(5-tert-butyl-benzoxazol-2-yl)thiophene.

[0291] Optional components

[0292] The formulation of the present invention may contain at least one additive, for example selected from the group consisting of fillers such as silica, antioxidants, antimicrobial compounds and antistatic compounds. The additive may be, for example, a chemically inert substance such as carbon black, silica (e.g., microsilica particles) and carbon nanotubes.

[0293] Method for manufacturing 3D articles

[0294] The present invention also relates to a method for manufacturing a 3D article using an additive manufacturing system, the method comprising:

[0295] - providing a polymer formulation (F) as described above,

[0296] - Printing a layer of the 3D article from the polymer formulation (F).

[0297] According to an embodiment, the printing step comprises irradiating the polymer formulation (F), for example irradiating a layer of such formulation (F) deposited on the printing surface with UV light. The layer preferably has a size ranging from 10 μm to 300 μm, for example from 50 μm to 150 μm.

[0298] The UV light may be, for example, a laser. The irradiation preferably has sufficient intensity to cause substantial curing of the polymer formulation (F), for example a layer of such a formulation (F). Furthermore, the irradiation preferably has sufficient intensity to cause adhesion of the layer of the polymer formulation (F).

[0299] According to another embodiment of the present invention, a method for manufacturing a 3D article using an additive manufacturing system comprises the following steps:

[0300] - providing a polymer formulation (F) as described above,

[0301] - Printing a layer of the 3D article from the polymer formulation (F) by the following steps:

[0302] a) applying a layer of the preparation (F) on the surface,

[0303] b) irradiating the layer with UV light, c) applying a layer of the formulation (F) on the previously irradiated layer,

[0304] d) irradiating the layer with UV light, and

[0305] e) Repeating steps c) and d) a sufficient number of times to produce the 3D article.

[0306] According to an embodiment, the polymer formulation (F) is at room temperature during the process. Alternatively, the formulation can be heated before and / or during printing, in particular if the polymer concentration in the formulation is high. In this case, the temperature can be heated to up to 130° C., up to 120° C. or up to 110° C. before and / or during printing.

[0307] application

[0308] The present invention furthermore relates to the use of a polymer (P) according to the invention or a polymer formulation (F) according to the invention for producing a 3D object / article.

[0309] All the above described embodiments concerning polymers (P) and polymer formulations (F) are equally applicable to the production of 3D objects / articles.

[0310] The present invention also relates to a 3D object or 3D article obtainable at least in part by the manufacturing method of the present invention, using the polymer (P) or polymer formulation (F) described herein.

[0311] The 3D objects or articles obtainable by such a manufacturing method can be used for a variety of end applications. Particular mention may be made of implantable devices, dental prostheses, stents and parts of complex shapes in the aerospace industry and under-the-hood parts in the automotive industry.

[0312] Should the disclosure of any patents, patent applications, and publications incorporated by reference into this application conflict with the description of the present application to the extent that it renders a term unclear, the present description shall take precedence.

[0313] The present invention will now be described in more detail with reference to the following examples, the purpose of which is merely illustrative and not limiting the scope of the present invention.

[0314] Examples

[0315] Example 1 - Synthesis of PSU polymer according to the present invention

[0316] Material

[0317] 4-(Dimethylamino)pyridine (DMAP) (Sigma-Aldrich, ≥99%), acryloyl chloride (Sigma-Aldrich, ≥97%), triethylamine (TEA) (Sigma-Aldrich, ≥99%), potassium carbonate (Fisher Chemical), toluene (Fisher Chemical), anhydrous N,N-dimethylacetamide (DMAc) (Acros Organics, 99.5%), sodium chloride (Fisher Chemical), magnesium sulfate (Spectrum), diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (97%, Sigma-Aldrich), sodium bicarbonate (Spectrum), hydrochloric acid (Fisher Scientific), and anhydrous chloroform (Sigma-Aldrich, ≥99%) were used as received. Bis(4-chlorophenyl)sulfone (98%) and bisphenol A (≥99%) were purchased from Sigma-Aldrich and recrystallized from toluene. Nitrogen (99.999%) was purchased from Praxair. All materials were used as received unless otherwise noted.

[0318] Analytical methods

[0319] 1 H nuclear magnetic resonance (NMR) spectroscopy was performed at 400 MHz using a Varian Unity 400 at 23 °C. 3 ) was used as solvent for all polymers.

[0320] The molecular weight (Mn) of the polymers was characterized relative to polystyrene standards at 35° C. using a Waters Acquity Advanced Permeation Chromatography (APC). An Acquity APC XT column was used with a flow rate of 1 mL / min and a sample concentration of 1 mg / mL.

[0321] The TA Instruments Q50 was used to 2 Thermogravimetric analysis (TGA) was performed at 10°C / min from 25°C to 600°C while the reaction mixture was flowing.

[0322] Differential Scanning Calorimetry (DSC) was performed using a TA instruments Q1000 DSC with an RCS90 refrigeration cooling system and a 50 mL / min nitrogen sample cell purge. The instrument was calibrated using indium (Tm = 156.60 °C) and zinc (Tm = 419.47 °C) standards. An initial heating rate of 10 °C / min was used, followed by a quench cooling of 100 °C / min to remove thermal history. A second thermal cycle at 10 °C / min was used to calculate thermal transitions. The glass transition temperature (Tg) was determined by the inflection point in the TA Universal Analysis software.

[0323] Photorheology was performed on a TA Instruments DHR-2 rheometer with 20 mm parallel plate geometry, Smart Swap TM The UV curing accessory and Omnicure S2000 light source were fitted with a broad spectrum bulb and a 320-500nm filter to allow wavelengths in this window to pass through the sample. The polymers were analyzed oscillating at 25°C using 0.3% strain and 4Hz. 2 The sample was subjected to 30 s of shaking before UV irradiation at an intensity of 1000 nm for 200 s.

[0324] Storage (G') and loss (G") shear moduli were obtained and analyzed using the TA TRIOS software package, and the G' / G" crossover point was determined by the software. The plateau modulus (G_N^0) was determined by averaging the last 100 data points in the storage modulus curve.

[0325] Step 1 - Synthesis of Hydroxyl Terminated PSU Polymer

[0326] This example illustrates the synthesis of hydroxyl terminated PSU polymers at controlled molecular weight according to the following Scheme 1:

[0327]

[0328] In order to control the molecular weight of the final polymer and to generate hydroxyl end groups, polysulfone (PSU) polymers are synthesized with excess bisphenol A monomer (BPA).

[0329] An example of the synthesis of PSU with a target Mn of 6,000 g / mol PSU (ratio of BPA:DCS = 1.08:1) is as follows: Bisphenol A (11.11 g, 0.049 mol), 4,4'-dichlorophenyl sulfone (12.98 g, 0.045 mol), potassium carbonate (8.07 g, 0.058 mol), anhydrous N,N-dimethylacetamide (160 mL) and toluene (80 mL) were weighed into a three-necked round-bottom flask equipped with a Dean-Stark trap and a mechanical stirring bar. 2The heterogeneous solution was purged for 10 min. The reaction was then heated at 160°C for 4 hours while monitoring the removal of water via a toluene / water azeotrope in a Dean-Stark trap. The reaction temperature was raised to 180°C and toluene was removed over 12 h. The resulting solution was filtered to remove salts. Purification was performed by precipitation into 4 L of distilled water. The resulting white polymer was filtered and dried overnight at 210°C in vacuo.

[0330] Step 2 - Synthesis of Acrylate Terminated PSU Polymer

[0331] This example illustrates the synthesis of acrylate terminated PSU polymers at controlled molecular weight according to the following Scheme 2:

[0332]

[0333] Scheme 2 outlines the general synthesis of acrylate-terminated PSU oligomers. PSU (5.00 g, 0.0009 mol) and DMAP (0.0058 g, 0.000048 mol) from Step 1 were charged into a 100 mL round bottom flask. 2 The reaction mixture was purged for 10 min, and then anhydrous CHCl was added. 3 The product of 4-nitropropene was stirred at 40 ℃ for 10 minutes at 40 ℃ for 2 hours.Then, add 4-nitropropene (50mL).Once uniform, the reaction is cooled to 0 ℃.Add triethylamine (0.74g, 0.0073mol) by syringe, and once dissolved, then add acryloyl chloride (0.41g, 0.0046mol) dropwise during 1min.Allow the reaction solution to be heated to room temperature overnight.Then the solution is washed twice with 2M HCl aqueous solution, to remove excessive DMAP, and excessive TEA is converted into salt form, and then stirred for 3h on basic alumina (about 5g).Then the solution is filtered, and then washed twice with saturated sodium bicarbonate solution, and finally washed once with salt water.The gained yellow solid is dried 18 hours in a vacuum at 40 ℃.

[0334] result

[0335] 1H NMR spectroscopy confirmed the quantitative conversion of hydroxyl terminated PSU to acrylate terminated PSU. The observation and integration of acrylate protons between 6-7 ppm relative to the backbone resonances is a clear indicator of quantitative termination.

[0336] The T of the final polymer was confirmed by differential scanning calorimetry at 20 °C / min. g =167℃.

[0337] Target Mn: 6,000 g / mol

[0338] GPC Mn: 5,700 g / mol

[0339] PDI: 2.41

[0340] Titration Mn: 7,260 g / mol

[0341] Example 2 - Printing of PSU polymer

[0342] Step 1 - Preparation of formulation

[0343] The components and the weight % of each component relative to the total weight of the formulation are shown in Table 1.

[0344]

[0345] Table 1 - Wt. %

[0346] Step 2 - Printing

[0347] The preparation was transferred to a glass beaker and brought into focus of the projector. The build platform was inserted into the resin beaker. The build platform was rinsed with the resin surface and then lowered 100 μm into the resin. The STL file of the test sample was cut into 100 μm slices and converted into a monochrome bitmap image. The build platform was set to 15 W / cm 2 Using a 365nm light source with a high intensity, a bitmap image corresponding to the first layer of the part is projected onto the resin surface for 8 seconds. The build platform is then lowered into the resin to re-apply a new layer of resin. Subsequent layers are fabricated using an exposure time of 8 seconds / layer, followed by a re-coating step. This process continues until the entire part is fabricated. The fabricated 3D part is extracted from the build platform and rinsed with NMP to remove any residual uncured resin. It is then wiped with Kim Wipes. TM Dry the parts and transfer them to a glass slide for measurement.

[0348] result

[0349] like Figure 2 As shown, the parts made with Comparative Formulation 1 did not fully exhibit the designed porosity. The pores were either completely closed or partially closed. This can be attributed to over-curing. This formulation resulted in parts with poor feature resolution.

[0350] like Figure 3 As shown, the parts made with Formulation 2 of the present invention exhibit all designed porosity. This can be attributed to the prevention of over-curing by the addition of the UV blocker avobenzone. This formulation results in the manufacture of parts with superior feature resolution.

Claims

1. A method for manufacturing a 3D article using an additive manufacturing system, the method comprising: - providing a polymer formulation (F), and - printing a layer of the 3D article from the polymer formulation (F), wherein the polymer formulation (F) comprises, based on the total weight of the formulation (F): - from 1 to 50 wt.%, based on the total weight of F, of at least one polymer (P), wherein the polymer (P) is a PSU comprising: - at least 50 mol.% of the repeating units are repeating units (R) of formula (LB) psu ), mol.% is based on the total moles in the polymer: - at least one terminal group having formula (M1), Wherein, R is H or CH3, wherein the polymer (P) has a number average molecular weight (Mn) of less than 40,000 g / mol, as determined by gel permeation chromatography (GPC) using dichloromethane as mobile phase and polystyrene standards, - at least one solvent selected from the group consisting of: N-methylpyrrolidone (NMP), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAC), 1,3-dimethyl-2-imidazolidinone, tetrahydrofuran (THF), dimethyl sulfoxide (DMSO) and sulfolane; - at least one photoinitiator selected from the group consisting of: 2,2-dimethoxy -2-phenylacetophenone (DMPA), diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide and phenyl bis (2,4,6-trimethylbenzoyl) phosphine oxide, and - at least one retardant selected from the group consisting of avobenzone and 2,5-bis(5-tert-butyl-benzoxazol-2-yl)thiophene.

2. The method of claim 1, wherein: The polymer (P) has a number average molecular weight (Mn) of less than 10,000 g / mol, as determined by gel permeation chromatography (GPC) using dichloromethane as mobile phase and polystyrene standards.

3. The method of claim 1, wherein: The printing step comprises irradiating the polymer formulation (F) with UV light.

4. The method of claim 3, wherein: The UV light is laser light.

5. A 3D article, at least partially obtained by the method according to any one of claims 1 to 4.

6. Use of the polymer formulation (F) as defined in the method of claim 1 or 2 for producing 3D objects by stereolithography.

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