CROSS-LINKABLE COMPOSITIONS HAVING A LOW VISCOSITY FOR COATINGS AND MATERIALS WITH A HIGH REFRACTIVE INDEX AND A HIGH HEAT DEFLECTION TEMPERATURE

Abstract

The invention relates to a crosslinkable composition which comprises a component a) at least one bisphenolfluoroene diglycidyl ether tetra(meth)acrylate, a component b) at least one diluent from the mono(meth)acrylates of a monoalcohol comprising a biphenyl, cumyl or benzyl structure, and at least one optional component from components c), d) and e). It also relates to its use for coatings or materials, in particular for 3D printed articles for optical applications, as it also relates to the crosslinked composition and to the finished product, in particular the 3D article which results therefrom.

Claims

1. A crosslinkable composition comprising: a) at least one biphenylfluorene diglycidyl ether tetra(meth)acrylate oligomer, b) at least one diluent from mono(meth)acrylates of a monoalcohol comprising a biphenyl, cumyl or benzyl structure, c) optionally at least one (meth)acrylate oligomer with a (meth)acrylate functionality of at least 2, selected from urethane (meth)acrylates or thiocarbamate (meth)acrylates, d) optionally at least one (meth)acrylate ester monomer or urethane (meth)acrylate monomer with a functionality of from 1 to 6, different from b), e) optionally at least one oligomer from polyester (meth)acrylate, polyether (meth)acrylate or epoxy (meth)acrylate with a functionality of from 1 to 15.

2. The composition according to claim 1, wherein said monomer d) is included and is selected from mono(meth)acrylic esters of C1 to C18 aliphatic alcohols or of C6 to C18 cycloaliphatic alcohols or from polyfunctional (meth)acrylic esters (of functionality 2 to 6) of C2 to C18 polyols, or from hydroxyalkyl (meth)acrylates, and optionally the said monomer d) comprises at least one unit of alkoxy structure.

3. The composition according to claim 1, wherein said oligomer e) is included and is selected from polyester (meth)acrylate or polyether (meth)acrylate or epoxy (meth)acrylate and has a (meth)acrylate functionality of from 1 to 10.

4. The composition according to claim 1, wherein said component a) is the bisphenolfluorene diglycidyl ether tetramethacrylate of formula (I) below: ##STR00004## or the bisphenolfluorene diglycidyl ether tetraacrylate of the same formula (I) except that the methyl group of the methacrylate is absent, with all of the methacrylate groups being replaced by acrylate groups.

5. The composition according to claim 1, wherein the component b) is the biphenyl methanol mono (meth)acrylate of formula (II) below or a compound of formula (III) or (IV): ##STR00005## with R being methyl or H.

6. The composition according to claim 1, wherein the content by weight of component a), with respect to the weight a)+b), varies from 20% to 80%.

7. The composition according to claim 1, wherein the content by weight of d), with respect to the weight a)+b), is from 5% to 50%.

8. The composition according to claim 1, wherein the content by weight of e), with respect to the weight a)+b), is from 5% to 50%.

9. The composition according to claim 1 further comprising at least one initiator.

10. The composition according to claim 9, wherein the at least one initiator is selected from a peroxide or hydroperoxide and can be crosslinked by the thermal route or at low temperature in the presence of a reducing accelerator of the peroxide or hydroperoxide.

11. The composition according to claim 9, wherein the at least one initiator is at least one photoinitiator and can be crosslinked by UV radiation, by laser or by LED.

12. The composition according to claim 1, wherein the composition does not comprise any initiator and can be crosslinked by EB (electron beam) radiation.

13. The composition according to claim 1, wherein the composition can be crosslinked by a dual route combining at least two crosslinking techniques selected from crosslinking by the thermal route, using as initiator a peroxide or hydroperoxide in the presence of a reducing accelerator of the said peroxide or hydroperoxide, crosslinking by UV radiation, laser or LED, using as initiator a photoinitiator, and crosslinking by radiation by electron beam.

14. The composition according to claim 1, wherein the composition has a viscosity at 25° C. according to the ISO 3219 (1993) method of less than 5000 mPa.s.

15. The composition according to claim 1, wherein, after crosslinking provides a crosslinked composition, the crosslinked composition has an HDT according to the ISO 075 (2004) method of at least 70° C.

16. The composition according to claim 1, wherein, after crosslinking provides a crosslinked composition, the crosslinked composition has a Young's modulus at 25° C. according to the ISO 527 (1993) method of at least 2500 MPa.

17. The composition according to claim 1, wherein the composition has an RI before crosslinking according to the ASTM D1218-12(2016) standard of at least 1.47 and, after crosslinking provides a crosslinked composition, the crosslinked composition has an RI of at least 1.50.

18. A method of making a coating comprising crosslinking a composition according to claim 1, wherein the coating has at least one of an HDT according to the ISO 075 (2004) method of at least 70° C. or an RI of at least 1.50.

19. (canceled)

20. A 3D printed article made by crosslinking the composition according to claim 1.

21. A 3D printed article according to claim 20, wherein the 3D printed article is printed by a layer-by-layer printing process or by a continuous process.

22. A 3D printed article according to claim 20 having a refractive index RI of at least 1.50.

23. An article or material made by crosslinking the composition according to claim 1, relating to optical applications and suitable for use as one of: plastic lenses, or optical coatings, or optical fibres, holograms, lenses for prisms and LED materials.

24. A crosslinked composition, resulting from crosslinking the composition according to claim 1.

25. (canceled)

26. (canceled)

27. (canceled)

Description

EXAMPLES

1) Formulations

[0092] The formulations of examples 1 to 6, containing biphenylfluorene diglycidyl ether tetramethacrylate, are prepared with the compounds described below, in the proportions indicated in Table 1 (% by weight with respect to the weight of the formulation): [0093] Compound A: biphenylfluorene diglycidyl ether tetramethacrylate [0094] Biphenylfluorene diglycidyl ether tetramethacrylate is prepared according to the same conditions described in U.S. Pat. No. 6,515,166 for preparing bisphenol A diglycidyl ether tetramethacrylate from bisphenol A diglycidyl ether, and these conditions are applied here to biphenylfluorene diglycidyl ether to give biphenylfluorene diglycidyl ether tetramethacrylate. [0095] Compound B: H008 from KPX Green Chemical, biphenyl-4-methanol acrylate [0096] Compound C: A011 from KPX Green Chemical, ethoxylated biphenyl-2-ol acrylate (1 EO) [0097] Compound D: A003M from KPX Green Chemical, benzyl methacrylate [0098] Compound E: CD590 from Sartomer, 4-cumylphenol acrylate [0099] Compound F: HPMA from Evonik, hydroxypropyl methacrylate [0100] Compound G: SR340 from Sartomer, 2-phenoxyethyl methacrylate

TABLE-US-00001 TABLE 1 Example Example Example Example Example Example Compound 1 2 3 4 5 6 A 51.0 64.0 48.0 46.0 50 50 B 9.0 / / / / / C / / 35.0 32.5 23.5 27.5 D / 20.0 / / 14.0 / E 25.0 16.0 12.0 11.5 12.5 12.5 F 15.0 / 5.0 10.0 / / G / / / / / 10.0 Total: 100.0 100.0 100.0 100.0 100.0 100.0

Characteristics of the Liquid Formulations Before Crosslinking

[0101] To characterize the liquid formulations, measurements of viscosity and refractive index are carried out under the following conditions: [0102] Brookfield viscosity: the viscosity was measured at 25° C. on a Brookfield DVII+ PRO viscometer according to the ISO 3219 (1993) standard [0103] Refractive index: the refractive index is measured on a BELLINGHAM+STANLEY RPM 960-T refractometer at 25° C. according to the ASTM D1218-12(2016) standard.

[0104] The results are presented in Table 2 below.

[0105] Characteristics of the liquid formulations of Examples 1 to 6

TABLE-US-00002 TABLE 2 Example Example Example Example Example Example 1 2 3 4 5 6 Refractive index 1.563 1.563 1.569 1.562 1.570 1.569 Brookfield viscosity 2270 4200 4000 2050 1880 4800 @ 25° C. (mPa .Math. s)

3) Physicochemical Characteristics After Crosslinking

[0106] Samples

[0107] The samples are prepared starting from silicone moulds. The bars (DMA, HDT) have the dimensions, in mm, of 80*10*4 and the test specimens of 5A type for the tensile testing have a thickness of 4 mm. The photoinitiator system is TPO-L (ethyl (2,4,6-trimethylbenzoyl)phenylphosphinate), 2% for all the formulas, and the crosslinking is carried out under a 100% UV bench LED lamp, followed by a post-cure at 80° C. for 12 hours.

[0108] Analytical Conditions

[0109] Tests carried out at 23° C. under a relative humidity (RH) of 50%. [0110] DMA Analysis

[0111] The DMA analysis is carried out on an RDAIII instrument (Rheometrics), in rectangular torsion, with a sweep from −50° C. to 200° C., at 3° C./min, and with a nominal strain of 0.05% and a frequency of 1 Hz. The transition temperature Tα is determined as being the temperature at the summit of the tan delta peak. [0112] HDT:

[0113] The HDT (Heat Deflection Temperature) tests are carried out on the HDT instrument (EDIT) according to the ISO 076 (2004) standard. Method A is used (1.8 MPa); the test specimen (thickness of 4 mm) is positioned flat on the substrate (distance between supports=64 mm). The heating rate is 120° C./h. [0114] Tensile Test:

[0115] The tensile tests are carried out on an MTS tensile testing device with 500 N cell according to the ISO 527 (1993) standard. The test specimens used are of 5A type. The pull rate is 1 mm/min and then 10 mm/min starting from 7% elongation. Determinations are made of the stress, the elongation at break and the Young's modulus.

[0116] Results

[0117] The results of the mechanical and thermomechanical tests carried out on the solid samples of the formulations of examples 1 to 6 rare given in Table 3 below.

[0118] Mechanical and thermomechanical performance qualifies of the formulations of examples 1 to 6

TABLE-US-00003 TABLE 3 Example Example Example Example Example Example 1 2 3 4 5 6 DMA (° C.) 154 163 137 134 133 137 HDT (° C.) 109 140 83 99 103 89 Tensile test Stress 30 19 26 13 12 20 (MPa) Elongation 1.5 1.3 1.2 1.0 1.0 1.2 at break (%) Young's 3200 3100 3200 3100 3000 3900 modulus (MPa)