UV CURABLE COMPOSITION FOR USE IN 3D PRINTING

Abstract

The present invention relates to photocurable compositions, comprising (A1) a N-vinyloxazolidinone of formula (I), wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are independently of each other a hydrogen atom or an organic group having not more than 10 carbon atoms, (A2) optionally one, or more second reactive diluents, (B) one, or more oligomers, and (C) a photoinitiator (C), wherein the amount of component (A1) is 5 to 70% by weight based on the amount of components (A1), (A2) and (B), wherein the viscosity of said photocurable composition is in the range 10 to 3000 mPa.Math.s, preferably 10 to 1500 mPa.Math.s at 30° C. The compositions, from which cured three-dimensional shaped articles having balanced mechanical properties combining stiffness with high toughness can be made, are particularly suitable for the production of three-dimensional articles by stereolithography and photopolymer jetting.

##STR00001##

Claims

1.-18. (canceled)

19. A photocurable composition, comprising (A1) a N-vinyloxazolidinone of formula ##STR00051## wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are independently of each other a hydrogen atom or an organic group having not more than 10 carbon atoms, (A2) optionally one, or more second reactive diluents, (B) one, or more oligomers, and (C) a photoinitiator (C), wherein the amount of component (A1) is 5 to 70% by weight based on the amount of components (A1), (A2) and (B), wherein the viscosity of said photocurable composition is in the range 10 to 3000 mPa.Math.s at 30° C.

20. The photocurable composition, wherein the amount of components (A1) and (A2) is 30 to 70% by weight, and the amount of component (B) is 70 to 30% by weight, based on the amount of components (A1), (A2) and (B).

21. The photocurable composition according to claim 19, wherein and least two of R.sup.1 to R.sup.4 in formula I are a hydrogen atom.

22. The photocurable composition according to claim 19, wherein the N-vinyloxazolidinone of formula I is selected from a compound, wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are a hydrogen atom, a compound, wherein R.sup.1 is a C.sub.1-C.sub.4alkyl group, and R.sup.2, R.sup.3 and R.sup.4 are a hydrogen atom, and a compound, wherein R.sup.1 and R.sup.2 are a hydrogen atom and R.sup.3 and R.sup.4 are a C.sub.1-C.sub.4alkyl group, and mixtures thereof.

23. The photocurable composition according to claim 19, wherein the oligomer (B) is selected from the group consisting of polyester acrylates, polyether acrylates, epoxy acrylates and urethane acrylates.

24. The photocurable composition according to claim 19, wherein the oligomer (B) is obtained by reacting (B1) a hydroxyalkylacrylate, or hydroxyalkylmethacrylate, (B2) an aliphatic diisocyanate, an aliphatic polyisocyanate, a cycloaliphatic diisocyanate, a cycloaliphatic polyisocyanate, an aromatic diisocyanate, or an aromatic polyisocyanate, or mixtures thereof, (B3) a polyester polyol, which is derived from aliphatic dicarboxylic acids and aliphatic diols, and (B4) optionally a secondary polyol.

25. The photocurable composition according to claim 24, wherein component (B1) is selected from the group consisting of 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2- or 3-hydroxypropyl acrylate, 2- or 3-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, and 4-hydroxybutyl acrylate, component (B2) is selected from the group consisting of 4,4′-, 2,4′- and/or 2,2′-methylenedicyclohexyl diisocyanate (H12MDI), isophorone diisocyanates (IPDI) and tolylene 2,4- and/or 2,6-diisocyanate (TDI) and the polyester polyol (B3) is derived from adipic acid and ethylene glycol and 1,4-butanediol ((poly(ethylene 1,4-butylene adipate) diol, PEBA).

26. The photocurable composition according to claim 23, wherein the oligomer (B) is obtained by reacting a polyalkylene glycol with a lactone of formula ##STR00052## at least one cycloaliphatic or asymmetric aliphatic diisocyanate and an hydroxyalkyl(meth)acrylate, or by reacting a lactone of formula (B) with at least one cycloaliphatic or asymmetric aliphatic diisocyanate and an hydroxyalkyl(meth)acrylate, wherein R.sup.113 is a divalent alkylene radical having 1 to 12 carbon atoms and which is optionally be substituted by C.sub.1-C.sub.4alkyl groups and/or interrupted by one or more oxygen atoms.

27. The photocurable composition according to claim 26, wherein the oligomer (B) is obtained by reacting c-caprolactone, 4,4′-, 2,4′- and/or 2,2′-methylenedicyclohexyl diisocyanate and hydroxyethylacrylate.

28. The photocurable composition according to claim 23, wherein the oligomer (B) is obtained by reacting aliphatic, aromatic, or cyclic diisocyanates with hydroxyalkyl(meth)acrylate.

29. The photocurable composition according to claim 19, wherein the photoinitiator (C) is selected from acylphosphine oxide compounds, benzophenone compounds, alpha-aminoketone compounds, phenylglyoxylate compounds, oxime ester compounds, mixtures thereof and mixtures with alpha-hydroxy ketone compounds, or alpha-alkoxyketone compounds.

30. The photocurable composition according to claim 19, wherein the photoinitiator (C) is a compound of the formula ##STR00053## wherein R.sub.50 is unsubstituted cyclohexyl, cyclopentyl, phenyl, naphthyl or biphenylyl; or is cyclohexyl, cyclopentyl, phenyl, naphthyl or biphenylyl substituted by one or more halogen, C.sub.1-C.sub.12alkyl, C.sub.1-C.sub.12alkoxy, C.sub.1-C.sub.12alkylthio or by NR.sub.53R.sub.54; or R.sub.50 is unsubstituted C.sub.1-C.sub.20alkyl or is C.sub.1-C.sub.20alkyl which is substituted by one or more halogen, C.sub.1-C.sub.12alkoxy, C.sub.1-C.sub.12alkylthio, NR.sub.53R.sub.54 or by —(CO)—O—C.sub.1-C.sub.24alkyl; R.sub.51 is unsubstituted cyclohexyl, cyclopentyl, phenyl, naphthyl or biphenylyl; or is cyclohexyl, cyclopentyl, phenyl, naphthyl or biphenylyl substituted by one or more halogen, C.sub.1-C.sub.12alkyl, C.sub.1-C.sub.12alkoxy, C.sub.1-C.sub.12alkylthio or by NR.sub.53R.sub.54; or R.sub.51 is —(CO)R′.sub.52; or R.sub.51 is C.sub.1-C.sub.12alkyl which is unsubstituted or substituted by one or more halogen, C.sub.1-C.sub.12alkoxy, C.sub.1-C.sub.12alkylthio, or by NR.sub.53R.sub.54; R.sub.52 and R′.sub.52 independently of each other are unsubstituted cyclohexyl, cyclopentyl, phenyl, naphthyl or biphenylyl, or are cyclohexyl, cyclopentyl, phenyl, naphthyl or biphenylyl substituted by one or more halogen, C.sub.1-C.sub.4alkyl or C.sub.1-C.sub.4alkoxy; or R.sub.52 is a 5- or 6-membered heterocyclic ring comprising an S atom or N atom; R.sub.53 and R.sub.54 independently of one another are hydrogen, unsubstituted C.sub.1-C.sub.12alkyl or C.sub.1-C.sub.12alkyl substituted by one or more OH or SH wherein the alkyl chain optionally is interrupted by one to four oxygen atoms; or R.sub.53 and R.sub.54 independently of one another are C.sub.2-C.sub.12-alkenyl, cyclopentyl, cyclohexyl, benzyl or phenyl, or the photoinitiator (C) is a mixture of a compound of the formula (XII) and a compound of the formula ##STR00054## wherein R.sub.29 is hydrogen or C.sub.1-C.sub.18alkoxy; R.sub.30 is hydrogen, C.sub.1-C.sub.18alkyl, C.sub.1-C.sub.12hydroxyalkyl,C.sub.1-C.sub.18alkoxy, OCH.sub.2CH.sub.2—OR.sub.34, morpholino, S—C.sub.1-C.sub.18alkyl, a group —HC═CH.sub.2, —C(CH.sub.3)═CH.sub.2, ##STR00055## D, E and f are 1-3; c is 2-10; G.sub.1 and G.sub.2 independently of one another are end groups of the polymeric structure; R.sub.34 is hydrogen, ##STR00056## R.sub.31 is hydroxy, C.sub.1-C.sub.16alkoxy, morpholino, dimethylamino or —O(CH.sub.2CH.sub.2O).sub.g—C.sub.1-C.sub.16alkyl; g is 1-20; R.sub.32 and R.sub.33 independently of one another are hydrogen, C.sub.1-C.sub.6alkyl, C.sub.1-C.sub.16alkoxy or —O(CH.sub.2CH.sub.2O).sub.gC.sub.1-C.sub.16alkyl; or are unsubstituted phenyl or benzyl; or phenyl or benzyl substituted by C.sub.1-C.sub.12-alkyl; or R.sub.32 and R.sub.33 together with the carbon atom to which they are attached form a cyclohexyl ring; R.sub.35 is hydrogen, OR.sub.36 or NR.sub.37R.sub.38; R.sub.36 is hydrogen, C.sub.1-C.sub.12alkyl which optionally is interrupted by one or more non-consecutive O-atoms and which uninterrupted or interrupted C.sub.1-C.sub.12alkyl optionally is substituted by one or more OH, or R.sub.36 is ##STR00057## R.sup.37 and R.sub.38 independently of each other are hydrogen or C.sub.1-C.sub.12alkyl which is unsubstituted or is substituted by one or more OH; R.sub.39 is C.sub.1-C.sub.12alkylene which optionally is interrupted by one or more non-consecutive O, —(CO)—NH—C.sub.1-C.sub.12alkylene-NH—(CO)— or ##STR00058## with the proviso that R.sub.31, R.sub.32 and R.sub.33 not all together are C.sub.1-C.sub.16alkoxy or —O(CH.sub.2CH.sub.2O).sub.g—C.sub.1-C.sub.16alkyl, or the photoinitiator is a mixture of different compounds of the formula (XII), or the photoinitiator is a mixture of compounds of the formula (XII) and (XI).

31. Use of the photocurable composition according to claim 19 in a photopolymerization 3D printing process, in particular vat photopolymerisation, or photopolymer jetting.

32. A method for producing a three-dimensional article, comprising a) providing the photocurable composition according to claim 19, b) exposing the photocurable composition to actinic radiation to form a cured crossection, c) repeating steps (a) and (b) to build up a three-dimensional article.

33. The method according to claim 32, comprising a vat photopolymerization, wherein the photocurable composition according to claim 19 in step b) is cured directly onto a translated or rotated substrate, and the irradiation is patterned via stereolithography, holography, or digital light projection (DLP).

34. The method according to claim 32, comprising a) applying a layer of the photocurable composition of claim 19 onto a surface; b) exposing the layer imagewise to actinic radiation to form an imaged cured cross-section; c) applying a second layer of the photocurable composition onto the previously exposed imaged cross-section; d) exposing the layer from step (c) imagewise to actinic radiation to form an additional imaged cross-section, wherein the radiation causes curing of the second layer in the exposed areas and adhesion to the previously exposed cross-section; and e) repeating steps (c) and (d) in order to build up a three-dimensional article.

35. A three-dimensional article produced by the method according to claim 32.

36. The three-dimensional article according to claim 35 having an Izod impact strength (unnotched) of greater than 45 kJ/m.sup.2 and/or an E modulus of greater than 1750 MPa.

37. The photocurable composition according to claim 19, wherein the viscosity of said photocurable composition is in the range 10 to 1500 mPa.Math.s at 30° C.

38. The photocurable composition, wherein the amount of components (A1) and (A2) is 50 to 70% by weight, and the amount of component (B) is 50 to 30% by weight based on the amount of components (A1), (A2) and (B).

Description

EXAMPLES

Viscosity:

[0227] The viscosity of the photocurable compositions was determined at 30° C. in accordance with DIN EN ISO 3219 using a cone/plate HR-1 Discovery Hybrid Rheometer (TA Instruments) and a cone of 60 mm diameter and an angle of 2° at a shear rate of 100 s.sup.−1.

Preparation of Specimen for Tensile (DIN ISO 527-1, Specimen Type 5A) and Impact Strength Tests (DIN ISO 180)

[0228] All specimen were prepared by casting using home-made silicone molds. After filling of the molds the photopolymers were pre-cured (pinning) in a light cabinet equipped with UVA fluorescent tubes (Sylvania blacklight 368, F40W, T12) for 60 seconds at 5.9 mW/cm.sup.2 irradiance (Gigahertz-Optik X1, sensor UV-3717-4), measured with UV-Control 3CT (UV-technik meyer GmbH). UV curing was performed on both sides of the specimen under a 365 nm UV-LED (Hoenle) in 5 passes (tensile specimen, 2 mm thickness) and 10 passes at 500 mJ/cm.sup.2.

TABLE-US-00001 Example1 Example 2 Example 3 Example 4 Component Wt-% Wt-% Wt-% Wt-% 5-methyl-3-vinyl- 69.50 49.50 39.50 39.50 oxazolidin-2-one Laromer ® UA 9089.sup.1) 29.50 49.50 59.50 — Visiomer ® HEMATMDI.sup.2) — — — 59.50 Omnirad ® TPO-L.sup.3) 1.00 1.00 1.00 1.00 Total 100.00 100.00 100.00 100.00 Viscosity [mPas] 27 113 259 74 at 30° C./100 s.sup.−1 E modulus [MPa] 2000 ± 32  1450 ± 31  1140 ± 32  2730 ± 59  Tensile strength at 47.0 ± 1.2 42.3 ± 2.6 50.8 ± 6.9  84.8 ± 3.3  break [MPa] Elongation at break [%] 29.8 ± 9.2  49.9 ± 12.6 79.8 ± 13.2 7.8 ± 4.3 Izod impact strength 49.6 ± 7.7 57.9 ± 9.9 60.1 ± 13.5 34.1 ± 12.6 (unnotched) [kJ/m.sup.2] .sup.1)BASF, .sup.2)Evonik, .sup.3)IGM Resins.

[0229] As shown in the above Table the mechanical properties of the cured compositions can be modified by changing the ratio of 5-methyl-3-vinyl-oxazolidin-2-one and the used oligomers to obtain materials with good mechanical performance, either focusing on high impact strength (Examples 1 to 3) or high E modulus (Example 4). In addition, the viscosity of the composition in Example 1 is very low which makes it suitable for photopolymer jetting. Low viscous resins are also desired for vat-based printing processes to ensure an efficient recoating step.