Composition for the manufacture of an ophthalmic lens comprising an encapsulated light-absorbing additive

Abstract

The present invention relates to a thermosetting composition for the manufacture of an ophthalmic lens which efficiently absorbs light rays without degradation of the light-absorbing additive, said composition comprising an allyl monomer or oligomer, a catalyst, at least one light-absorbing additive contained in nanoparticles which are dispersed in said allyl monomer or allyl oligomer. The present invention also relates to the use of said composition and to the ophthalmic lens obtained from said composition.

Claims

1. A polymerizable liquid composition for the manufacture of an ophthalmic lens, comprising: a) at least one allyl monomer or allyl oligomer, b) at least one catalyst for initiating the polymerization of said allyl monomer or allyl oligomer, c) at least one light-absorbing additive not contained in core-shell nanoparticles and homogeneously dispersed in non-core-shell nanoparticles, wherein said non-core-shell nanoparticles are dispersed in said allyl monomer or allyl oligomer.

2. The composition according to claim 1, wherein the light-absorbing additive is selected from the group consisting of a colorant; a colorless light-absorbing additive; and mixtures thereof.

3. The composition according to claim 1, wherein the non-core-shell nanoparticles comprise a polymer.

4. The composition according to claim 1, wherein the non-core-shell nanoparticles comprise a mineral oxide.

5. The composition according to claim 1, wherein the refractive index of the non-core-shell nanoparticles is from 1.47 to 1.56, as measured according to the ISO 489:1999.

6. The composition according to claim 1, wherein the non-core-shell nanoparticles exhibit a size of from 1 nm to 10 μm, as measured according to the Dynamic Light Scattering method.

7. The composition according to claim 1, wherein the amount of light-absorbing additive in the non-core-shell nanoparticles is from 0.0001 to 90 wt % based on the weight of the non-core-shell nanoparticles.

8. The composition according to claim 1, wherein the amount of non-core-shell nanoparticles in the composition is from 0.01 to 2 wt % based on the weight of the composition.

9. The composition according to claim 1, wherein the allyl monomer or oligomer is selected in the group consisting of diethylene glycol bis(allyl carbonate), ethylene glycol bis(allyl carbonate), oligomers of diethylene glycol bis(allyl carbonate), oligomers of ethylene glycol bis(allyl carbonate), bisphenol A bis(allyl carbonate), diallyl phthalate, diallyl isophthalate, diallyl terephthalate and mixtures thereof.

10. The composition according to claim 1, wherein the catalyst is selected in the group consisting of a peroxodicarbonate, a peroxyester, a perketal, and mixtures thereof.

11. A process for the preparation of the polymerizable liquid composition as defined in claim 1, comprising the steps of: a) providing an allyl monomer or allyl oligomer; b) providing a light-absorbing additive not contained in core-shell nanoparticles and homogeneously dispersed in non-core-shell nanoparticles in the form of a powder of nanoparticles dispersible within said allyl monomer or allyl oligomer or in the form of a dispersion of said nanoparticles in a liquid dispersible within said allyl monomer or allyl oligomer; c) providing a catalyst for initiating the polymerization of said allyl monomer or allyl oligomer; and d) mixing said allyl monomer or allyl oligomer, said light-absorbing additive contained in nanoparticles and said catalyst.

12. A process for preventing degradation of a light-absorbing additive by a catalyst for initiating polymerization of an allyl monomer or allyl oligomer comprising: obtaining at least one allyl monomer or allyl oligomer; obtaining at least one catalyst for initiating the polymerization of said allyl monomer or allyl oligomer; obtaining a light-absorbing additive not contained in core-shell nanoparticles, wherein said light-absorbing additive is comprised in in non-core-shell nanoparticles; and mixing the at least one allyl monomer or allyl oligomer, the at least one catalyst for initiating the polymerization of said allyl monomer or allyl oligomer, and the light-absorbing additive comprised in non-core-shell nanoparticles to obtain a polymerizable liquid composition as defined in claim 1, wherein the light-absorbing additive in non-core-shell nanoparticles is homogenously dispersed in said non-core-shell nanoparticles.

13. An ophthalmic lens obtained by curing the polymerizable liquid composition as defined in claim 1.

14. An ophthalmic lens comprising: a) an optical substrate; b) a coating obtained by curing the polymerizable liquid composition as defined in claim 1 on said optical substrate.

15. An ophthalmic lens comprising a composite substrate comprising: a) a matrix obtained by polymerization of at least one allyl monomer or allyl oligomer in presence of a catalyst for initiating the polymerization of said allyl monomer or allyl oligomer; and b) non-core-shell nanoparticles containing at least one light-absorbing additive not contained in core-shell nanoparticles, wherein said at least one light-absorbing additive is homogeneously dispersed in said non-core-shell nanoparticles and said non-core-shell nanoparticles are dispersed in said matrix.

Description

EXAMPLES

(1) Measuring Methods

(2) The following measures are carried out on a lens that is 2 mm thick in its center and that has been cleaned with isopropyl alcohol.

(3) The average (or mean) light transmittance over 420-450 nm range (TB %) is computed from transmittance curve measured according to ISO 8980-3-2003.

(4) The size of the nanoparticles is measured by standard Dynamic Light Scattering method. The technique measures the time-dependent fluctuations in the intensity of scattered light from a suspension of nanoparticles undergoing random Brownian motion. Analysis of these intensity fluctuations allows for the determination of the diffusion coefficients, which, using the Stokes-Einstein relationship can be expressed as the particle size.

(5) Haze value is measured by light transmission measurement using the Haze-Guard Plus© haze meter from BYK-Gardner (a color difference meter) according to the method of ASTM D1003-00. All references to “haze” values in this application are by this standard. The instrument is first calibrated according to the manufacturer's instructions. Next, the sample is placed on the transmission light beam of the pre-calibrated meter and the haze value is recorded from three different specimen locations and averaged.

(6) Colorimetric coefficients of the lenses of the invention are measured according to the international colorimetric system CIE L*a*b*, i.e. calculated between 380 and 780 nm, taking the standard illuminant D 65 at angle of incidence 15° and the observer into account (angle of 10°).

(7) Materials

(8) In the examples, the following compounds are used:

(9) TABLE-US-00001 Component CAS number Function CR-39 ® 142-22-3 allyl monomer CR-39E ® allyl monomer (as disclosed in U.S. Pat. No. 7,214,754) IPP 105-64-6 catalyst methyl methacrylate 80-62-6 monomer to prepare polymer- based nanoparticles ethylene glycol 97-90-5 reticulating agent to prepare dimethacrylate polymer-based nanoparticles 2,2′-Azobis(2,4- 4419-11-8 catalyst dimethylvaleronitrile) (AIVN) tetraethyl 78-10-4 precursor for mineral-based orthosilicate (TEOS) nanoparticles sodium 151-21-3 ionic surfactant dodecylsulfate (SDS) Triton X-100 9002-93-1 surfactant

Example 1: Preparation of Polymer-Based Nanoparticles Containing a Light-Absorbing Additive by Miniemulsion Polymerization

(10) A monomer blend (5 g) is prepared from methyl methacrylate and ethylene glycol dimethacrylate in a weight ratio of 50:50, and OMNISTAB™ 47 (10 mg, available from Deltachem Co. Ltd.) is dissolved in this monomer blend. This blend is added dropwise to 50 ml of an aqueous solution containing SDS (0.5 g) and AIVN (0.05 g) at 80° C. under a nitrogen atmosphere. After completion of the monomer blend addition, the mixture is then further mixed for additional 2 h at 80° C., then centrifuged, washed with ethanol, and dried. The nanoparticles have a size in the range of 200 nm to 1000 nm and a refractive index of 1.5.

(11) The nanoparticles are dispersed in CR39® (12.5 weight % nanoparticles in monomer) to prepare a masterbatch (Master 1).

Example 2: Preparation of Mineral-Based Nanoparticles Containing a Light-Absorbing Additive by Reverse Microemulsion

(12) Ex. 2a: A mixture of cyclohexane (7.5 ml), n-hexanol (1.8 ml), Triton X-100 (1.5 g), OMNISTAB™ 47 (40 mg, available from Deltachem Co; Ltd), TEOS (0.1 ml) and ammonium hydroxide 30% (0.06 ml) are mixed for 24 h. Then, acetone is added and the particles are collected by centrifugation, washed with ethanol and dried. The nanoparticles have a monodisperse size centered on 100 nm and a refractive index corresponding to precipitated silica, around 1.47.

(13) The nanoparticles are dispersed in CR-39 (12.5 weight % nanoparticles in monomer) to prepare a masterbatch (Master 2a).

(14) Ex. 2b: 7.56 g of Triton X-100, 5.86 g hexan-1-ol, 23.46 g cyclohexane, 1.6 ml deionized water, 0.32 ml of methylene blue solution (CAS: 61-73-4, 1% weight solution in water) which is the light-absorbing additive, 0.4 ml of TEOS, and 0.24 ml of 30% ammonium hydroxide solution in water are mixed and stirred at room temperature for 24 h.

(15) After 24 h, one volume of acetone (around 50 ml) is added to the obtained solution, and the particles are collected by centrifugation, washed with acetone or water, dried overnight at room temperature, and annealed in an oven at 80° C. for 3 hours.

(16) 0.2 g of the obtained dried mineral nanoparticles are then redispersed under magnetic stirring in approx. 20 ml acetone and zirconium beads having size of 1 mm as grinding agents. The mixture is finally filtered to remove zirconium beads. 99.8 g of CR-39® is then added and the acetone is stripped out under vacuum so as to obtain a masterbtach (Master 2b).

(17) Ex. 2c: 7.56 g of Triton X-100, 30 ml of hexan-1-ol, 7.2 ml of cyclohexane, 1.6 ml deionized water, 0.32 ml of methylene blue solution (CAS: 61-73-4, 1% weight solution in water) which is the light-absorbing additive, 0.4 ml of TEOS, and 0.24 ml of 30% ammonium hydroxide solution in water are mixed and stirred at room temperature for 24 h.

(18) After 24 h, one volume of acetone (around 50 ml) is added to the obtained solution, and the particles are collected by centrifugation, washed with acetone or water, dried overnight at room temperature. The nanoparticles have a monodisperse size of 100 nm and a refractive index corresponding to precipitated silica, around 1.47.

(19) Nanoparticles are dispersed in CR-39® as in example 2b, to prepare a masterbatch (Master 2c).

(20) Ex. 2d: Ex. 2c was reproduced (Master 2d), except that 1.76 ml of deionized water was used instead of 1.6 ml and 7.4 g of Triton X-100 instead of 7.54 g. The nanoparticles have a monodisperse size of 80 nm.

(21) Ex. 2e: Ex. 2c was reproduced (Master 2e), except that 2.16 ml of deionized water was used instead of 1.6 ml and 7 g of Triton X-100 instead of 7.54 g. The nanoparticles have a monodisperse size of 50 nm.

(22) Examples 2c to 2e show that the ratio between deionized water and Triton X-100 defines the final size of nanoparticles: the higher the ratio, the smaller the nanoparticles.

(23) Ex. 2f: Ex. 2c was reproduced (Master 2f), except that 1.44 ml of deionized water was used instead of 1.6 ml and 7 g of Triton X-100 instead of 7.54 g. Further, 0.16 ml of 5,10,15,20-Tetrakis(4-sulfonatophenyl)-porphine-Cu(II) (TSPP—Cu(II)) solution (0.01 M in deionized water) was added. The nanoparticles have a monodisperse size of 100 nm.

(24) Other light absorbing agents have been used with the same preparation procedure, as summarized in the table A below.

(25) TABLE-US-00002 TABLE A Color Index number (C.I.) Molecule 60730 Acid Violet 43 42090 Acid Blue 9 42051 Acid Blue 3 (Patent Blue V) 74180 Solvent Blue 38 (for microscopy Luxol® Fast Blue MBSN) 20470 Acid Black 1 42045 Acid Blue 1 TSPP-Cu(II)

Example 3: Preparation of Mineral-Based Nanoparticles Containing a Light-Absorbing Additive by Stober Process

(26) 384 mL of methanol is added in 1000 ml bottle. Then, 96 ml of NH.sub.4OH (30% weight solution in water) and 6.4 mL of methylene blue (CAS: 61-73-4, 2% weight solution in deionized water) are added. The mixture is stirred (magnetic stirring) at 400 rpm for 10 min. After that, 3.2 ml of TEOS is added dropwise and stirred at 800 rpm for 2 h.

(27) After reaction is complete, particle size is checked by Dynamic Light Scattering. The average particle size is around 200-230 nm (mono-disperse).

(28) Mixture is transferred to round bottle flask for evaporating 1 h in order to reduce the volume of methanol from 500 to 100 ml, then, centrifuged at 4000 rpm for 45 min. Supernatant is removed and nanoparticles are retrieved as concentrated dispersion in methanol.

(29) Mixture is then cleaned two times with the following procedure: 50 ml of methanol is added with sonication to re-disperse particle. Nanoparticles are collected by centrifugation at 4000 rpm for 30 min.

(30) Nanoparticles are air dried at ambient temperature overnight, then grinded in an agathe mortar. Then nanoparticles are annealed at 180° C. for 2 hours.

(31) 0.3 g of nanoparticle is mixed with 99.7 g of CR-39 monomer in 250 ml bottle. The master-batch is sonicated for 30 min. Centrifugation at 4000 rpm for 30 min is applied to remove the agglomerated particle. The supernatant is collected to obtain a master-batch (Master 3).

Example 4: Preparation of Ophthalmic Lenses According to the Invention

(32) TABLE-US-00003 Material Parts by weight CR39 ® 95.00 CR39E ® 2.00 Master 1 or 2a-f or 3 2.00 IPP 2.40

(33) The monomer blend is manufactured by weighing and mixing the ingredients in a beaker at room temperature. CR39® and CR39E® are first mixed. Once homogeneous, nanoparticles in masterbatch are added then the beaker content is mixed again until full dispersion. Finally, IPP is added and the mixture is stirred thoroughly, then degassed and filtered.

(34) A 71 mm diameter glass bi-plano mold was then filled with the composition using a syringe and the polymerization was carried out in a regulated electronic oven in which the temperature was gradually increased from 45° C. to 85° C. in 15 hours then kept constant at 85° C. for 5 hours. The mold was then disassembled and the resulting lens had a 2 mm thickness in its center.

(35) As shown in FIG. 1, the transmission spectum of the composition comprising Master 1 before polymerization and the transmission spectum of the lens after polymerization show the same transmittance reduction for the maximum absorption wavelength of the light-absorbing additive (424 nm). As such, in the ophthalmic lens according to the present invention the dye has not been degraded by the IPP catalyst during polymerization. Differences in both spectra outside the absorption domain of the light-absorbing additive are obviously linked to the chemical transformation occurring during polymerization (catalyst dissociation, reaction of unsaturated groups . . . ).

(36) As shown in FIG. 2, the resulting ophthalmic lens has an average transmittance TB % of 77% in the range of 420 nm to 450 nm. In comparison, the same ophthalmic lens comprising non-encapsulated dye has an average transmittance TB % of 91%. As such, the ophthalmic lens comprising an encapsulated dye according to the present invention exhibits a better absorption of blue light than the corresponding ophthalmic lens comprising a non-encapsulated dye.

(37) The effects of methylene blue as the light absorbing additive, on haze (light diffusion), particle size and residual color of the lens (as measured by b* according to CIE Lab model) were evaluated with various nanoparticles. Conditions of Example 2b are reproduced, except that the concentration of methylene blue aqueous solution is varied between 0.4% and 1% by increments of 0.2%, yielding nanoparticles with different concentrations of methylene blue.

(38) The increase of methylene blue concentration in nanoparticles showed a positive trend on haze, because less particles were required to obtain the same colouring effect. With particles obtained with 1% methylene blue solution, average transmittance TB % is decreased from 0.5 to 0.3 compared to the particles obtained with 0.4% methylene blue solution, without degrading haze performance.

(39) Increasing the methylene blue concentration also led to an increase in particle size: at 0.4%, the measured particle size was around 80 nm, whereas it was around 90 nm at 0.6%, and 95 nm at both 0.8% and 1%.

(40) Measurements also showed that the haze generated by deionized water washed nanoparticles is around 20-40% lower than that of acetone washed nanoparticles, for a similar residual color (measured by b* reduction in Lab system).