Liquid polymerizable composition comprising an anhydride derivative monomer and mineral nanoparticles dispersed therein, and its use to manufacture an optical article

Abstract

A liquid polymerizable composition including an anhydride derivative monomer with mineral nanoparticles homogeneously dispersed therein, as well as its use for the preparation of a transparent polymeric material having a high refractive index and its use in the optical field.

Claims

1. A liquid polymerizable composition comprising: a liquid monomer composition containing a monomer of formula (I): ##STR00007## wherein: R and R, identical or different, represent a hydrogen atom or a methyl group, X is O, S, NR1- or CR2R3-, R1 is selected from the group consisting of aryl, heteroaryl, aryl C1-C6 alkyl and heteroaryl C1-C6 alkyl, R2 and R3, identical or different, are selected from the group consisting of aryl, heteroaryl, aryl C1-C6 alkyl, heteroaryl C1-C6 alkyl, aryloxy, arylthio, aryl C1-C10 alkyloxy, heteroaryl C1-C10 alkyloxy, aryl C1-C10 alkylthio, and heteroaryl C1-C10 alkylthio, and mineral nanoparticles homogeneously dispersed in said monomer composition, wherein said mineral nanoparticles consist of a material selected from the group consisting of ZnS, ZrO.sub.2, TiO.sub.2 and BaTiO.sub.3.

2. The liquid polymerizable composition of claim 1, wherein in formula (I), R and R are identical.

3. The liquid polymerizable composition of claim 1, wherein in formula (I), X is O, NR1- or CR2R3-.

4. The liquid polymerizable composition of claim 1, wherein in formula (I), X is O.

5. The liquid polymerizable composition of claim 1, wherein in formula (I), X is NR1- and R1 is selected from the group consisting of aryl, heteroaryl, aryl C1-C6 alkyl and heteroaryl C1-C6 alkyl.

6. The liquid polymerizable composition of claim 1, wherein in formula (I), X is CR2R3- and R2 and R3, identical or different, are selected from the group consisting of aryl, heteroaryl, aryl C1-C6 alkyl, heteroaryl C1-C6 alkyl, aryloxy, arylthio, aryl C1-C10 alkyloxy, heteroaryl C1-C10 alkyloxy, aryl C1-C10 alkylthio, and heteroaryl C1-C10 alkylthio.

7. The liquid polymerizable composition of claim 1, wherein said nanoparticles have a particle size less than 50 nm.

8. The liquid polymerizable composition of claim 1, wherein the amount of said mineral nanoparticles in the polymerizable composition is comprised between 5% w/w and 60% w/w, based on the total weight of the liquid polymerizable composition.

9. An optical substrate coated with the liquid composition according to claim 1.

10. The optical substrate according to claim 9, wherein the article is an ophthalmic lens or an optical lens for optical instrument.

11. An optical article cured of the liquid composition according to claim 1.

12. An optical article comprising: (a) an optical substrate, and (b) a coating obtained by thermal and/or UV curing of the liquid polymerizable composition according to claim 1.

13. The optical article according to claim 12, wherein the article is an ophthalmic lens or an optical lens for optical instrument.

14. The liquid polymerizable composition of claim 1, wherein the monomer of formula (I) is methacrylic anhydride.

15. The liquid polymerizable composition of claim 1, wherein said nanoparticles have a particle size between 30 nm and 5 nm.

16. The liquid polymerizable composition of claim 1, wherein the amount of said mineral nanoparticles in the polymerizable composition is comprised between 10% w/w and 50% w/w, based on the total weight of the liquid polymerizable composition.

17. A process for increasing the refractive index of a polymeric material obtained by thermal and/or UV curing of a liquid monomer composition containing a monomer of formula (I): ##STR00008## wherein: R and R, identical or different, represent a hydrogen atom or a methyl group, X is O, S, NR1- or CR2R3-, R1 is selected from the group consisting of aryl, heteroaryl, aryl C1-C6 alkyl and heteroaryl C1-C6 alkyl, R2 and R3, identical or different, are selected from the group consisting of aryl, heteroaryl, aryl C1-C6 alkyl, heteroaryl C1-C6 alkyl, aryloxy, arylthio, aryl C1-C10 alkyloxy, heteroaryl C1-C10 alkyloxy, aryl C1-C10 alkylthio, and heteroaryl C1-C10 alkylthio, and said process comprising the step of homogeneously dispersing mineral nanoparticles in said monomer composition, wherein said mineral nanoparticles consist of a material selected from the group consisting of ZnS, ZrO.sub.2, TiO.sub.2 and BaTiO.sub.3.

Description

(1) FIG. 1 shows the variation of the refractive index (n) according to the loading of ZnS nanoparticles (wt %) respectively at 473 nm, 594 nm and 654 nm.

(2) FIG. 2 shows the variation of the transmittance (T) according to the wavelength (nm) for every ZnS loading (wt %).

(3) FIG. 3 shows the front scattering of the polymer for every ZnS loading (wt %).

(4) The invention will now be further described in the following examples. These examples are offered to illustrate the invention and should in no way be viewed as limiting the invention.

EXAMPLES

1) Preparation of ZnS Nanoparticles Coated with a Thiol-Containing Compound

(5) Zn(OAc).sub.2, the capping agent and thiourea (TUA) are dissolved in DMF. Then the solution is heated under reflux at 160 C. under nitrogen atmosphere. At the end of the heating process, a transparent solution is obtained. The solution is poured in methanol, acetonitrile or water to induce the precipitation of the ZnS nanoparticles. Nanoparticles of ZnS are separated from the solution by centrifugation and washed with methanol or acetonitrile twice. The powder is dried under vacuum for 10 hours.

(6) The capping agents used in this experiment are mercaptoethanol (ME) (CAS: 60-24-2), and thiophenol (PhS) (CAS: 108-98-5).

(7) The relative molar amounts of Zn(OAc).sub.2, the capping agent and thiourea are indicated in table 1.

(8) The amount of capping agent is chosen so that during reflux and after cooling of the mixture, no self-precipitation occurs. Relative molar amounts leading to a stable dispersion are indicated in table 1.

(9) TABLE-US-00001 TABLE 1 Compound Relative molar amounts ME 0.6 PhS 0.3 Zn(OAc)2 1 TUA 1.65

(10) The mean crystal size of the ZnS nanoparticles (without coating) was determined according to the Williamson-Hall method. The mean crystal size of the ZnS nanoparticles was evaluated at 3.58 nm with a relative dispersion of 4.5% (measured by XR diffraction).

(11) The particle size of the coated ZnS nanoparticles was measured using Horiba SZ-100 size measurement instrument after cooling of the dispersion in DMF. The results show a particle size of around 7 nm with a narrow distribution size going from 4 to 14 nm. This small particle size and narrow distribution size allow the limitation of light scattering in the final composite.

2) Preparation of a Liquid Polymerizable Composition Comprising ZnS Nanoparticles Coated with a Thiol-Containing Compound Dispersed in Methacrylic Anhydride

(12) ZnS nanoparticles coated with PhS and ME were introduced into methacrylic anhydride (marketed by Aldrich, CAS: 760-93-0 under the commercial name methacrylic anhydride) in a vial at 60 C. under ultrasonic waves during one day, in various amounts (10 wt %, 20 wt % 30 w %, 40 wt %, 50 wt %, 60 wt %, 70 wt %). Homogeneous dispersions could be obtained up to 60 wt %. At 70 wt %, the dispersion is not completely homogenous. In fact, it can be observed some aggregates having a size higher than 100 nm.

(13) The obtained compositions were applied between two glass plates separated by a spacer of 500 m. Photopolymerization was performed after addition of 1 wt % of a radical photoinitiator (Irgacure184, BASF) and illumination with a Hg lamp during 10 min (450 mW.Math.cm.sup.2). Photopolymerization was induced between two glass substrates to avoid the inhibition by oxygen. A Silicon spacer of 500 m was used between the two glass substrates. The resulting thickness of the cured material was 500 m. For the 60 wt % and 70 wt % compositions, photopolymerization was performed directly in the vial because the viscosity of the compositions was too high to use the glass substrates.

(14) The refractive index (n) of the cured material was measured after demolding using a Metricon 2010M (prism coupling method). The results are indicated in table 2.

(15) TABLE-US-00002 TABLE 2 Amount of Refractive index nanoparticles of the cured material at dispersed various wavelengths n (wt %) 473 nm 594 nm 654 nm at 594 nm Abbe number 0% 1.535 1.524 1.522 45 10% 1.549 1.539 1.535 0.015 44 20% 1.579 1.566 1.560 0.042 38 30% 1.601 1.586 1.582 0.062 33 40% 1.625 1.609 1.605 0.085 33 50% 1.656 1.638 1.633 0.114 32 60% 1.689 1.663 1.659 0.139 26 70% 1.746 1.721 1.714 0.197 25

(16) The data of table 2 shows that the refractive index of the polymer may be increased by 0.197 at 594 nm with the addition of 70 wt % of ZnS nanoparticles compared with the same polymer without nanoparticles.

(17) Furthermore, at every wavelength, the refractive index of the polymer increases with increasing amounts of ZnS nanoparticles. The maximum refractive index obtained is 1.746 at 473 nm with 70 wt % of ZnS nanoparticles.

(18) The transmittance at 400 nm was measured with a spectrophotometer UV-Vis (Hitachi U-4100).

(19) Haze was measured after demolding with a spectrophotometer UV-Vis (Hitachi U-4100) according to Japanese Industrial Standard No 7136-2000 (equivalent to ISO 14782-1999).

(20) Front scattering was measured with a spectrophotometer UV-Vis (Hitachi U-4100). Transmittance, front scattering and haze are indicated in table 3.

(21) TABLE-US-00003 TABLE 3 Optical properties 0 wt % 10 wt % 20 wt % 30 wt % 40 wt % 50 wt % T (400 nm) 87% .sup.86% 85% 78% 82% 78% Front 1.2% 0.91% 2.2% 1.8% 1.4% 5.8% Scattering 400-800 nm Haze: 392 nm 1.2% 0.87% 2.2% 1.9% 1.3% 6.5% 436 nm 1.1% 0.77% 2.1% 1.6% 1.2% 6.0% 544 nm 0.97% 0.62% 1.9% 1.5% 1.1% 5.5% 653 nm 0.90% 0.54% 1.8% 1.4% 1.0% 5.2%

(22) The data of table 3 shows that haze is lower than 5% when loading of nanoparticles is below 50 wt %, which indicates the good dispersing behaviour of ZnS nanoparticles into methacrylic anhydride. When the loading of nanoparticles is higher than 50 wt %, haze is higher than 5% due to some aggregation of the nanoparticles.

(23) At 60 wt % and 70 wt %, transmittance and haze could not be measured.

(24) FIG. 1 shows the variation of the refractive index (n) according to the loading of ZnS nanoparticles (wt %) respectively at 473 nm, 594 nm and 654 nm.

(25) FIG. 2 shows the variation of the transmittance (T) according to the wavelength (nm) for every ZnS loading (wt %).

(26) FIG. 3 shows the front scattering of the prepared samples. If concentration is less then 50 wt %, the dispersion is homogeneous.

3) Preparation of a Liquid Polymerizable Composition Comprising ZrO2 Nanoparticles Dispersed in Methacrylic Anhydride

(27) Five compositions were prepared by adding to methacrylic anhydride (marketed by Aldrich, CAS: 760-93-0 under the commercial name methacrylic anhydride) respectively 10 wt %, 20 wt %, 30 wt %, 40 wt % and 50 wt % of ZrO.sub.2 from a suspension of ZrO.sub.2/MeOH (30 wt % in MeOH, commercially available from Sakai chemical), and then adding to this mixture 3 wt % of Irgacure 184 (a radical photoinitiator marketed by BASF). The methanol of the resulting composition was evaporated under reduced pressure. Methacrylic anhydride could homogeneously disperse ZrO.sub.2 nanoparticles up to 60 wt %.

(28) Then, each composition was applied between two glass plates separated by a spacer of 500 m. Photopolymerization was performed by illumination with a Hg lamp during 10 min (15 mW.Math.cm.sup.2). Photopolymerization was induced between two glass substrates to avoid the inhibition by oxygen. A Silicon spacer of 500 m was used between the two glass substrates.

(29) The refractive indexes and Abbe number of the resulting materials are indicated in table 4.

(30) TABLE-US-00004 TABLE 4 Amount of Refractive index nanoparticles of the cured material at dispersed various wavelengths n (wt %) 473 nm 594 nm 654 nm at 594 nm Abbe number 0% 1.535 1.524 1.522 45 10% 1.546 1.536 1.532 0.012 43 20% 1.564 1.553 1.549 0.029 41 30% 1.590 1.578 1.574 0.054 40 50% 1.642 1.628 1.624 0.104 38

(31) The data of table 4 shows that the refractive index of the polymer may be increased by 0.104 at 594 nm with the addition of 50 wt % of ZrO.sub.2 nanoparticles compared with the same polymer without nanoparticles.

(32) Furthermore, at every wavelength, the refractive index of the polymer increases with increasing amounts of ZrO.sub.2 nanoparticles. The maximum refractive index obtained is 1.642 at 473 nm with 50 wt % of ZrO.sub.2 nanoparticles.

(33) By comparing the data of table 2 with the data of table 4, it appears that the increase of the refractive index of the polymer is higher with ZnS nanoparticles than with ZrO.sub.2 nanoparticles.

(34) Transmittance at 400 nm, front scattering and haze are indicated in table 5.

(35) TABLE-US-00005 TABLE 5 Optical properties 0 wt % 10 wt % 20 wt % 30 wt % 50 wt % T (400 nm) 87% 79% 79% 55% 67% Front Scattering 1.2% 3.6% 2.6% 3.4% 5.3% 400-800 nm Haze: 392 nm 1.2% 3.9% 2.7% 5.6% 5.7% 436 nm 1.1% 3.7% 2.6% 4.5% 5.4% 544 nm 0.97% 3.5% 2.6% 3.4% 5.2% 653 nm 0.90% 3.1% 2.2% 2.7% 4.8%

(36) The data of table 5 shows that the haze is lower than 5% when loading of nanoparticles is below 50 wt %, which indicates good dispersion of the ZrO2 nanoparticles into methacrylic anhydride.

4) Preparation of a Liquid Polymerizable Composition Comprising ZrO2 Nanoparticles Dispersed in N-Phenethyl Diacrylimide

(37) The following compound was synthetized according to protocol described in literature (Org. Biomol. Chem., 2006, 4, 3973-3979):

(38) ##STR00004##

(39) Seven compositions were prepared by adding to freshly prepared N-phenethyl diacrylimide) respectively 10 wt %, 20 wt %, 30 wt %, 40 wt %, 50 wt % and 60 wt % of ZrO.sub.2 from a suspension of ZrO.sub.2/MeOH (30 wt % in MeOH, commercially available from Sakai chemical), and then adding to this mixture 3 wt % of Irgacure 184 (a radical photoinitiator marketed by BASF). The methanol of the resulting composition was evaporated under reduced pressure. N-phenetyl diacrylimide could homogeneously disperse ZrO.sub.2 nanoparticles up to 30 wt %.

(40) Then, each composition was applied between two glass plates separated by a spacer of 500 m. Photopolymerization was performed by illumination with a Hg lamp during 10 min (15 mW.Math.cm.sup.2). Photopolymerization was induced between two glass substrates to avoid the inhibition by oxygen. A Silicon spacer of 500 m was used between the two glass substrates.

(41) The refractive indexes, Abbe number, transmittance and haze of the resulting materials are indicated in table 6.

(42) TABLE-US-00006 TABLE 6 Optical properties 0 wt % 10 wt % 20 wt % 30 wt % 40 wt % 50 wt % 60 wt % 594 nm 1.566 1.590 1.599 1.617 1.647 1.657 1.692 n 0.024 0.033 0.051 0.081 0.091 0.126 Abbe Number 35 37 37 32 23 34 19 T (400 nm) 65% 59% 36% 40% 13% Front 5.7% 4.9% 4.4% 7.0% 12% scattering 400-800 nm Haze 390 nm 7.2% 6.9% 9.3% 12% 31% 435 nm 6.7% 6.2% 6.9% 9.9% 21% 545 nm 5.5% 4.6% 4.2% 6.8% 12% 655 nm 4.4% 3.5% 2.8% 5.3% 9.7%

(43) The data of table 6 shows that ZrO.sub.2 is homogenously dispersed in the polymerizable composition up 30 wt %. Aggregates are formed at higher concentrations.

5) Comparative Examples

(44) ZnS nanoparticles as prepared in example 1 were introduced in the following compounds. 2,5-dipentanone: no dispersion was observed. It may be due to the electronic repulsion of the carbonyl groups which prevents good chelation to the nanoparticle.

(45) ##STR00005## Acetylacetone: no dispersion was observed. It may be due to the fact that the predominant species is the tautomeric form bearing intramolecular H bonding.

(46) ##STR00006##