Blue light cutting optical material having a bluish appearance

Abstract

The present invention relates to an optical material cutting blue light, comprising at least one UV absorber that at least partially blocks light having a wavelength ranging from 400 to 450 nm, at least one absorbing dye A having its maximum absorption wavelength in the range from 520 nm to 640 nm, the optical material being made of a material chosen from polythiourethane materials, polyurethane urea materials, materials resulting from the polymerization or copolymerization of polyepisulfide monomers or oligomers, and materials resulting from the polymerization or copolymerization of allylic monomers or oligomers, the optical material having a colorimetric coefficient b* as defined in the CIE (1976) L*a*b* international colorimetric system that is lower than or equal to 6, and a hue angle h higher than or equal to 120° and lower than or equal to 180°, for an optical material thickness of 2 mm.

Claims

1. An optical material comprising: at least one UV absorber that at least partially blocks light having a wavelength ranging from 400 to 450 nm; at least one absorbing dye A having its maximum absorption wavelength in the range from 520 nm to 640 nm; wherein the optical material: is made of a material chosen from polythiourethane materials, polyurethane urea materials, materials resulting from the polymerization or copolymerization of polyepisulfide monomers or oligomers, and materials resulting from the polymerization or copolymerization of allylic monomers or oligomers; has a colorimetric coefficient b* as defined in CIE (1976) L*a*b* international colorimetric system that is lower than or equal to 6, for an optical material thickness of 2 mm; and has a hue angle h as defined in CIE (1976) L*a*b* international colorimetric system higher than or equal to 120º and lower than or equal to 180º, for an optical material thickness of 2 mm.

2. The optical material of claim 1, further defined as having a hue angle h as defined in CIE (1976) L*a*b* international colorimetric system higher than or equal to 1200 and lower than or equal to 145º, for an optical material thickness of 2 mm.

3. The optical material of claim 1, wherein said absorbing dye A has a maximum absorption wavelength in the range from 550 nm to 610 nm.

4. The optical material of claim 1, wherein said absorbing dye A is an anthraquinone dye.

5. The optical material of claim 4, wherein said absorbing dye A is Solvent Violet 33 or Solvent Violet 13.

6. The optical material of claim 1, further defined as having a relative light transmission factor in the visible spectrum Tv, as defined in standard NF EN 1836, higher than or equal to 82%.

7. The optical material of claim 1, further defined as having a colorimetric coefficient a* as defined in CIE (1976) L*a*b* international colorimetric system that is lower than or equal to 3, for an optical material thickness of 2 mm.

8. The optical material of claim 1, further defined as having a colorimetric coefficient b* as defined in CIE (1976) L*a*b* international colorimetric system that is lower than or equal to 5.5, for an optical material thickness of 2 mm.

9. The optical material of claim 8, further defined as having a colorimetric coefficient b* as defined in CIE (1976) L*a*b* international colorimetric system that is lower than or equal to 5, for an optical material thickness of 2 mm.

10. The optical material of claim 1, further defined as being made of a material chosen from polythiourethane materials and materials resulting from the polymerization or copolymerization of polyepisulfide monomers or oligomers.

11. The optical material of claim 1, wherein the absorbing dyes A are present in an amount ranging from 0.1 to 1000 ppm by weight, relative to the total weight of the optical material.

12. The optical material of claim 1, wherein the UV absorbers are present in an amount ranging from 0.05 to 4% by weight, relative to the total weight of the optical material.

13. The optical material of claim 1, further defined as not comprising any absorbing dye C having a maximum absorption wavelength of 500 nm or greater and less than 550 nm.

14. The optical material of claim 1, further comprising at least one absorbing dye B having its maximum absorption wavelength in the range from 410 nm to 450 nm.

15. An optical article comprising a substrate with a front main face and a rear main face, wherein said substrate comprises the optical material of claim 1.

16. The optical article of claim 15, further defined as an ophthalmic lens.

17. An optical article comprising a substrate with a front main face and a rear main face, wherein said substrate comprises an optical material including at least one UV absorber that at least partially blocks light having a wavelength ranging from 400 to 450 nm, at least one absorbing dye A having its maximum absorption wavelength in the range from 520 nm to 640 nm, the optical material being made of a material chosen from polythiourethane materials, polyurethane urea materials, materials resulting from the polymerization or copolymerization of polyepisulfide monomers or oligomers, and materials resulting from the polymerization or copolymerization of allylic monomers or oligomers, the optical article: having a colorimetric coefficient b* as defined in CIE (1976) L*a*b* international colorimetric system that is lower than or equal to 6, for an optical material thickness of 2 mm; and having a hue angle h as defined in CIE (1976) L*a*b* international colorimetric system higher than or equal to 120º and lower than or equal to 180º, for an optical material thickness of 2 mm.

18. A method for manufacturing the optical material of claim 1, comprising: preparing an optical material composition by mixing at least one UV absorber that at least partially blocks light having a wavelength ranging from 400 to 450 nm, at least one absorbing dye A having its maximum absorption wavelength in the range from 520 nm to 640 nm, and a material or compounds chosen from a polythiourethane material or precursors thereof, a polyurethane urea material or precursors thereof, a material resulting from the polymerization or copolymerization of polyepisulfide monomers or oligomers or a precursor thereof, and a material resulting from the polymerization or copolymerization of allylic monomers or oligomers or a precursor thereof; and curing said an optical material composition.

Description

EXAMPLES

(1) 1. Chemicals Used

(2) Optical materials were prepared from a composition comprising polymerizable monomers, dimethyltin dichloride as a catalyst (CAS No. 753-73-1), Diaresin Blue J® (bluing agent also known as Solvent Violet 33, CAS No. 86090-40-6, supplied by Mitsubishi Chemical Corporation) or Solvent Violet 13 (CAS No. 81-48-1, supplied by Clariant) as an absorbing dye A, Zelec UN® as a mold release agent, one or more UV absorbers for at least partially inhibiting light having a wavelength ranging from 400 to 450 nm and optionally ABS-420® as an absorbing dye B having its maximum absorption wavelength in the range from 410 nm to 450 nm (selective yellow dye having a narrow absorption peak centered at around 421 nm, supplied by Exciton Inc.).

(3) The monomers used in the present examples were norbornane diisocyanate (ISO, CAS No. 74091-64-8), the pentaerythritol tetrakis (3-mercaptopropionate) (THIOL1, CAS No. 7575-23-7), and 2,3-bis((2-mercaptoethyl)thio)-1-propanethiol (THIOL2, CAS No. 131538-00-6), in order to produce the polythiourethane matrix having a refractive index of 1.6.

(4) The UV absorbers according to the invention used in the examples were Seesorb® 709 (2-(2-hydroxy-5-tert-octylphenyl)benzotriazole, CAS No. 3147-75-9, supplied by Shipro Kasei Kaisha), Seesorb® 703 (2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-5-chlorobenzotriazole, CAS No. 3896-11-5, supplied by Shipro Kasei Kaisha), Eversorb® 109 (n-octyl-3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazol-2-yl)phenyl] propionate, CAS No. 83044-89-7, UV absorber offering protection against blue light, supplied by Everlight Chemical), 5-chloro-2-hydroxybenzophenone (noted UV absorber 1, CAS No. 85-19-8, supplied by Sigma-Aldrich), Eusolex® 9020 (4-tert-butyl-4′-methoxydibenzoylmethane, also known as avobenzone, CAS No. 70356-09-1, supplied by Merck KGaA), Tinuvin® 928 (2-[2-hydroxy-3-(dimethylbenzyl)-5-(1,1,3,3-tetramethylbutyl) phenyl]-2H-benzotriazole), and Tinuvin® 1600 (2-[4,6-bis(1,1′-biphenyl-4-yl)-1,3,5-triazine-2-yl]-5-[(2-ethylhexyl)oxy]phenol, supplied by BASF).

(5) 2. Manufacture of Lenses by Casting

(6) Convex and concave molds were assembled by using typing process. A center thickness adjustment was made to obtain 2 mm thick samples.

(7) The formulations of examples 1-2628 were prepared in small batch size by using a 100 mL Duran bottle with a glass tube for nitrogen intake and a vacuum connection. The UV absorber component was mixed with the ISO monomer (isocyanate part) at room temperature (25° C.) until a homogeneous mixture was obtained or, if the UV absorber was not dissolved at room temperature (25° C.), under moderate heat (30° C.).

(8) The dimethyl tin dichloride catalyst was added in the reaction mixture, which was then cooled down to 10° C. prior to addition of the thiol monomers THIOL1 and THIOL2, and stirred under vacuum until homogeneous. The absorbing dyes and the mold release agent were added at the end of the preparation. In some embodiments, absorbing dye A is introduced as a solution in the monomer THIOL2.

(9) The assembled molds were filled with the final formulations using a syringe, and the polymerization reaction was carried out in a regulated electronic oven at maximum 130° C. for 1 day. The molds were then disassembled to obtain plano (no power) lenses with 2 mm center thickness comprising a body of a thermoset material. The lenses were cleaned by immersion and sonication in a surfactant solution, then rinsed and dried.

(10) 3. Characterizations

(11) The optical characteristics of the lenses were determined using a Cary 4000 spectrophotometer from Hunter. The light transmission factor in the visible spectrum Tv was measured in transmission mode from a wearer's view angle, with the back (concave) side of the lens (2 mm thickness at the center) facing the detector and light incoming on the front side of the lens. Tv was measured under D65 illumination conditions (daylight). The light cut-off wavelength was determined from the transmission spectra.

(12) The yellowness index Yi of the prepared lenses was calculated as described above, by measuring on a white background with the above spectrophotometer the CIE tristimulus values X, Y, Z such as described in the standard ASTM E 313-05, through reflection measures, with the front (convex) side of the lens facing the detector and light incoming on said front side. This way of measuring Yi, from an observer's view angle, is the closest to the actual wearing situation.

(13) Protection from phototoxic blue light was evidenced by calculating the mean blue light protection factor BVC between 400 nm and 450 nm, weighted by the light hazard function B′(A), based on the transmission spectrum. Such factor is defined through the following relation and measured at 0° incidence:

(14) $\mathrm{BVC}=100\%-\frac{{\int }_{400}^{450}{B}^{\prime }\left(\lambda \right).Math.T\left(\lambda \right).Math.d\lambda }{{\int }_{400}^{450}{B}^{\prime }\left(\lambda \right).Math.d\lambda }$

(15) wherein T(λ) represents the lens transmission factor at a given wavelength, measured at an incident angle between 0 to 17°, preferably at 0°, and B′(λ) represents the light hazard function shown on figure 1 of publication WO 2017/077359, in the name of the Applicant (relative spectral function efficiency). Said light hazard function results from work between Paris Vision Institute and Essilor International. It can be seen on this figure that blue light is the most dangerous to human eye at 428-431 nm. A few values of the B′(λ) function between 400 and 450 nm are given hereunder:

(16) TABLE-US-00001 Wavelength (nm) Weighting coefficient B′(λ) 400 0.1618 410 0.3263 420 0.8496 430 1.00 440 0.6469 450 0.4237

(17) Resistance of the inventive lenses to photo-degradation was evaluated following exposure to the sun conditions of the Q-sun test. The Q-sun test consists in introducing the prepared material in a Q-SUN® Xe-3 xenon chamber, reproducing full spectrum sunlight, purchased from Q-LAB, at a relative humidity of 20% (±5%) and at a temperature of 23° C. (±5° C.), and exposing it to irradiation for 40 h or 80 h. The optical characteristics of the lenses were measured by Cary 4000 spectrophotometer again to get a new transmission spectrum and calculate the changes caused by the Q-sun test.

(18) 4. Formulations Prepared and Results

(19) The formulations prepared and the characterizations of these formulations and the final lenses are shown in the tables hereunder.

(20) TABLE-US-00002 Compound Examples (parts by weight) 1 2 3 4 5 6 7 ISO 49.9395 49.9395 49.9395 49.9395 50.1437 50.1437 50.1437 THIOL1 23.5880 23.5880 23.5880 23.5880 23.6845 23.6845 23.6845 THIOL2 25.1669 25.1669 25.1669 25.1669 25.2698 25.2697 25.2697 Catalyst 0.0395 0.0395 0.0395 0.0395 0.0396 0.0396 0.0396 Zelec UN ® 0.0691 0.0691 0.0691 0.0691 0.0694 0.0694 0.0694 Seesorb ® 709 1.1843 1.1843 1.1843 1.1843 Seesorb ® 703 0.0123 0.0123 0.0123 0.0123 Eversorb ® 109 0.7928 0.7928 0.7928 Tinuvin ® 1600 Dye A (bluing agent) 0.000197 0.000217 0.000237 0.000257 0.000248 0.000297 0.000347 Diaresin Blue J ® Dye B (yellow dye) 0.000049 0.000049 0.000049 0.000049 Yi 2.02 1.82 1.47 1.23 2.12 1.54 0.82 L* 94.64 94.63 94.51 94.42 94.31 94.18 94.02 a* −1.32 −1.33 −1.35 −1.37 −2.34 −2.33 −2.33 b* 1.71 1.61 1.43 1.31 2.94 2.62 2.24 C* 2.16 2.08 1.96 1.89 3.75 3.50 3.23 h (°) 127.73 129.60 133.30 136.18 128.50 131.58 136.13 BVC (%) 24 24 24 24 34 33 33 Light cut-off (nm) 396 396 396 396 406 406 406 Tv (%) 86.73 86.68 86.41 86.16 85.97 85.63 85.23 Compound Examples (parts by weight) 8 9 10 ISO 50.3432 50.3432 50.3432 THIOL1 23.7787 23.7787 23.7787 THIOL2 25.3703 25.3702 25.3701 Catalyst 0.0398 0.0398 0.0398 Zelec UN ® 0.0696 0.0696 0.0696 Tinuvin ® 1600 0.3980 0.3980 0.3980 Dye A (bluing agent) 0.000298 0.000398 0.000497 Diaresin Blue J ® Yi 0.76 0.15 −1.80 L* 93.57 93.52 92.69 a* −2.08 −2.01 −1.98 b* 1.66 1.29 0.27 C* 2.69 2.41 2.00 h (°) 142.17 147.90 172.20 BVC (%) 29 28 29 Light cut-off (nm) 394 393 393 Tv (%) 84.17 84.03 82.04 Compound Examples (parts by weight) 11 12 13 14 15 16 ISO 50.3834 50.3834 50.3834 50.2433 50.2433 50.2433 THIOL1 23.7977 23.7977 23.7977 23.7315 23.7315 23.7315 THIOL2 25.3906 25.3905 25.3904 25.3199 25.3198 25.3197 Catalyst 0.0398 0.0398 0.0398 0.0397 0.0397 0.0397 Zelec UN ® 0.0697 0.0697 0.0697 0.0695 0.0695 0.0695 UV 0.3186 0.3186 0.3186 absorber 1 Eusolex ® 9020 0.5958 0.5958 0.5958 Dye A (bluing agent) 0.000199 0.000299 0.000398 0.000298 0.000397 0.000496 Diaresin Blue J ® Yi 2.86 1.55 0.22 2.81 1.84 0.39 L* 94.76 94.25 93.78 94.23 93.64 93.15 a* −2.07 −2.06 −2.04 −2.41 −2.50 −2.47 b* 2.87 2.15 1.43 3.21 2.73 1.96 C* 3.54 2.98 2.49 4.01 3.70 3.15 h (°) 125.93 133.80 145.00 126.88 132.50 141.73 BVC (%) 29 29 29 32 33 33 Light cut-off (nm) 393 393 393 407 407 407 Tv (%) 87.04 85.80 84.63 85.79 84.36 83.17 Compound Examples (parts by weight) Cl 17 18 19 20 21 ISO 49.02 49.02 49.02 49.02 49.02 49.02 THIOL1 23.16 23.16 23.16 23.16 23.16 23.16 THIOL2 24.71 23.35 23.16 22.96 22.77 22.57 Catalyst 0.04 0.04 0.04 0.04 0.04 0.04 Zelec UN ® 0.05 0.05 0.05 0.05 0.05 0.05 Seesorb ® 709 1.94 1.94 1.94 1.94 1.94 1.94 Seesorb ® 703 0.12 0.12 0.12 0.12 0.12 0.12 Tinuvin ® 928 0.97 0.97 0.97 0.97 0.97 0.97 Dye A (bluing agent) 1.36 1.55 1.74 1.94 2.13 Solvent Violet 13 Yi 5.3 3.4 2.86 2.8 2.5 2.3 L* 95.7 94.9 95.1 94.9 94.8 94.7 a* −2.4 −2.4 −2.32 −2.4 −2.4 −2.4 b* 4.7 3.7 3.24 3.4 3.2 3.1 C* 5.3 4.4 4.06 4.1 4 3.9 h (°) 116.8 122.9 124.8 125.5 126.8 128 BVC (%) 33.3 33.7 33.2 33.3 33 33.1 Light cut-off (nm) 407 407 407 407 407 407 Tv (%) 89.5 87.5 87.8 87.3 87.2 86.9 Compound Examples (parts by weight) 22 23 24 25 26 ISO 49.02 49.02 49.02 49.02 49.02 THIOL1 23.16 23.16 23.16 23.16 23.16 THIOL2 22.96 22.77 22.57 22.38 22.19 Catalyst 0.04 0.04 0.04 0.04 0.04 Zelec UN ® 0.05 0.05 0.05 0.05 0.05 Seesorb ® 709 1.94 1.94 1.94 1.94 1.94 Seesorb ® 703 0.12 0.12 0.12 0.12 0.12 Tinuvin ® 928 0.97 0.97 0.97 0.97 0.97 Diaresin Blue J ® 1.74 1.94 2.13 2.33 2.52 Yi 3.1 2.9 2.87 2.4 2.3 L* 94.9 94.8 94.7 94.5 94.3 a* −2.3 −2.4 −2.43 −2.4 −2.4 b* 3.5 3.4 3.42 3.1 3.1 C* 4.2 4.1 4.19 3.9 3.9 h (°) 124 125 125.4 127.3 127.9 BVC (%) 33.1 33.2 33.1 33.4 34 Light cut-off (nm) 407 407 407 407 407 Tv (%) 87.3 87.1 86.8 86.5 85.9

(21) TABLE-US-00003 Q-sun Light Time cut-off ΔYi Δb* Example (h) (nm) Tv (%) Yi L* a* b* C* h*(°) (%) (%) 18 0 407 87.8 2.86 95.1 −2.32 3.34 4.06 124.8 — — Dye A: 40 406 87.5 2.87 94.9 −2.30 3.32 4.04 124.7 0.35 −0.60 Solvent 80 406 87.6 2.88 95.0 −2.29 3.32 4.04 124.6 0.70 −0.60 Violet 13 24 0 407 86.8 2.87 94.7 −2.43 3.42 4.19 125.4 — — Dye A: 40 407 86.9 2.81 94.7 −2.38 3.35 4.11 125.4 −2.09 −2.05 Diaresin 80 407 86.9 2.92 94.7 −2.41 3.43 4.19 125.1 1.74 0.29 Blue J ®

(22) Lenses with blue light cutting feature were made using different additives for reducing transmission of light in the range 400-450 nm (various UV absorbers partially blocking blue light, and an absorbing dye B in examples 1-4), and the color generated by these additives was modified by adding various levels of absorbing dye A as a bluing agent. Increasing the amounts of bluing agent allows to obtain a range of lenses with increasing bluish aspect.

(23) The results show that the optical articles according to the invention achieved good protection from blue light (BVC: 24-34%), good protection from UV light (light cut-off wavelength≥393 nm), high transmission in the visible spectrum (Tv>82%, without any antireflective coatings), and good cosmetic appearance (low Yi).

(24) Increasing the amount of absorbing dye A (bluing agent) lowers the transmission (Tv), the yellowness index Yi and b*, while a* remains constant, thus adding a “pure blue” contribution without green or red trend.

(25) The absence of significant variation of Yi and b* after Q-sun testing for 80 h indicates that the absorbing dyes A used are photo-stable: lenses do not appear more yellow after ageing under harsh UV exposure.

(26) Sensory Analysis

(27) Tests performed confirmed better acceptance of lenses according to the invention.

(28) 1.sup.st Test:

(29) On a panel of 5 people, lenses according to the invention were positioned on a white plastic polymer substrate mat and without optical brightener and their tinge observed in transmission under a non direct fluorescent source to avoid as much as possible seeing light reflection on the lens surface.

(30) For all observers, the lenses were spontaneously identified as having a bluish tinge.

(31) 2.sup.nd Test:

(32) Lenses of the invention were positioned and observed as in the first test with comparative lenses, namely commercial blue light cutting lenses having the following features:

(33) a*=−1.9, b*=3.6 h=118° C.=4.1 BVC=28% Tv(D65)=95%

(34) All lenses of the invention were preferred in view of the comparative commercial lenses that are seen yellow-green.