LIQUID POLYMERIZABLE COMPOSITION COMPRISING MINERAL NANOPARTICLES AND ITS USE TO MANUFACTURE AN OPTICAL ARTICLE

Abstract

Disclosed is a liquid polymerizable composition including a phosphine oxide or a phosphine sulphide monomer composition 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. An optical article comprising an optical substrate coated with a cured liquid polymerizable composition comprising: a liquid monomer composition containing: a monomer of formula (I): ##STR00032## wherein: X is an oxygen atom or a sulphur atom, at least one among R1, R2 and R3, identical or different, represents a polymerizable function which is directly linked to P or linked to P via a C1-C20alkylene, one or several carbon atoms of which may be replaced with: —O—, —S—, —NH— or —NR— wherein R is a C1-C10 alkyl group, a divalent monocycloalkyl or bicycloalkyl comprising 5 to 9 carbon atoms, optionally substituted with 1 to 4 groups independently chosen among an halogen atom, C1-C6 alkyl, C1-C6 alkoxy, or C1-C6 alkylthio, or a phenyl or naphtyl, optionally substituted with 1 to 4 groups independently chosen among an halogen atom, C1-C6 alkyl, C1-C6 alkoxy, or C1-C6 alkylthio, and the other(s) among R1, R2 and R3, identical or different, represent(s) an hydrogen atom, a C1-C10alkoxy, C1-C10alkylthio, phenyl, aryloxy, arylthio, arylC1-C10alkyloxy, or aryl C1-C10alkylthio, or or a mixture of two different monomers M1 and M2 which are able to react together and form the monomer of formula (I), wherein M1 or M2 or both M1 and M2 contain the function P═X and M1 and M2 further contain functions which are able to react together to form a polymer, and mineral nanoparticles homogeneously dispersed in said monomer composition of formula (I) or in said mixture of two different monomers M1 and M2 which are able to react together and form the monomer of formula (I).

2. The optical article of claim 1, wherein said mineral nanoparticles are chosen among ZnS, ZrO.sub.2, TiO.sub.2 or BaTiO.sub.3.

3. The optical article of claim 1, wherein said polymerizable function is selected from the group consisting of vinyl, allyl, isocyanate, thioisocyanate, acrylate, thioacrylate, methacrylate, thiomethacrylate, ether, thioether, alcohol, epoxy, thiol, and episulfide.

4. The optical article of claim 1, wherein the other(s) among R1, R2 and R3 bearing no polymerizable function, identical or different, represent(s) a phenyl, aryloxy, arylthio, arylC1-C10alkyloxy, or aryl C1-C10alkylthio.

5. The optical article of claim 1, wherein said monomer of formula (Ia) is a phosphine oxide of formula (Ia): ##STR00033## wherein: at least one among Ria, Rea and Ria, identical or different, represents: —(R4).sub.n—X—(R5-Y).sub.m—(R6).sub.p-Q wherein: R4, R5 and R6, identical or different, represent a C1-C6 alkylene group, one or several carbon atoms of which may be replaced with a phenylene group, X and Y, identical or different, represent O, S, or —NR—, wherein R is a C1-C6 alkyl group, n, m and p, identical or different, represent an integer from 0 to 4, Q represents a polymerizable function, chosen from acrylate, methacrylate, episulfide, or thiol, and the other(s) among R.sub.1a, R.sub.2a and R.sub.3a, identical or different, represent(s) an hydrogen atom, a phenyl, an C1-C6alkoxy, C1-C6alkylthio, aryloxy, arylthio, aryl C1-C6alkoxy, or aryl C1-C6alkylthio.

6. The optical article of claim 1, wherein said phosphine oxide of formula (Ia) is selected from the group consisting of: ##STR00034## ##STR00035## ##STR00036##

7. The optical article of claim 1, wherein said nanoparticles have a particle size less than 50 nm.

8. The optical article of claim 1, wherein said nanoparticles are chosen among of ZnS nanoparticles coated with one or more thiol-containing compounds.

9. The optical article of claim 8, wherein said ZnS nanoparticles are coated with mercaptoethanol, thiophenol, mercaptophenol, or a mixture thereof.

10. The optical article of claim 8, wherein said nanoparticles of ZnS are coated with a mixture of mercaptoethanol and thiophenol, with a molar ratio of mercaptoethanol and thiophenol over Zn comprised between 2.0 and 0.1.

11. The optical article of claim 8, wherein said nanoparticles of ZnS are coated with mercaptoethanol with a molar ratio of mercaptoethanol over ZnS is comprised between 1.3 and 1.6.

12. The optical article of claim 8, wherein said nanoparticles of ZnS have crystal size comprised between 3 and 10 nm, and the particle size of the nanoparticles of ZnS coated with said thiol-containing compound(s) is comprised between 4 and 80 nm.

13. The optical article of claim 1, wherein the amount of said mineral nanoparticles in the polymerizable composition is comprised between 5 and 50% w/w based on the total weight of the liquid polymerizable composition.

14. The optical article according to claim 1, wherein the article is an ophthalmic lens or an optical lens for optical instrument.

15. The optical article according to claim 1, wherein the optical substrate is a thermoplastic resin or a thermoset or photocured resin.

Description

EXAMPLES

[0160] 1) Preparation of ZnS Nanoparticles Coated with a Thiol-Containing Compound.

[0161] Zn(OAc).sub.2, the capping agent and thiourea (TUA) are dissolved in DMF. The glassware set-up is purge with nitrogen during 10 min. Then the solution is heated under reflux at 160° C. under small nitrogen flow. 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 dryed under vacuum for 10 hours.

[0162] The capping agents used in this set of experiments are mercaptoethanol (ME) (60-24-2), thiophenol (PhS) (108-98-5), and mercaptophenol (MPhO) (637-89-8).

[0163] The relative molar amounts of Zn(OAc).sub.2, the capping agent and thiourea are indicated in table 3.

[0164] The amount of capping agent is chosen so that during reflux and after cooling of the mixture, no self-precipitation occurs. Examples of relative molar amounts leading to a stable dispersion are indicated in table 3. A mixture of 2 different capping agents allows the use of a lower amounts of capping agent.

TABLE-US-00004 TABLE 3 Relative molar amounts Experiment Experiment Experiment Experiment Compound 1 2 3 4 ME 2.18 0.6 0.44 0 PhS 0 0.3 0.44 0 MPhO 0 0 0 2.78 Zn(OAc)2 1 1 1 1 TUA 1.65 1.65 1.65 1.65

[0165] An XRD analysis was performed on the powder of ZnS-ME from experiment 1. The results show that the ZnS particles have a sphalerite structure.

[0166] 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).

[0167] The particle size of the coated ZnS nanoparticles obtained from experiment 3 was measured using Horiba SZ-100 size measurement instrument after cooling of the dispersion in DMF.

[0168] 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 Liquid Polymerizable Composition Comprising ZnS Nanoparticles Coated with a Thiol-Containing Compound Dispersed in a Phosphine Oxide Containing Monomer.

[0169] ZnS nanoparticles coated with PhS, ME and/or MPhO were introduced into the following phosphine oxide monomer 1 and 2 (marketed by Osaka Organic Chemicals respectively under the commercial name Viscoat 3-PA® and 3-PMA®) at 60° C. under ultrasonic waves. Table 4 gives the maximum amount of particles that can be homogeneously dispersed in the monomers 1 and 2.

##STR00031##

TABLE-US-00005 TABLE 4 Molar amount of the capping agent relative to ZnS PhS ME MPhO 3PA 3PMA 0.3 0.6  — Up to 20 wt % N/A 0.88 — — Up to 20 wt % Up to 20 wt % — 2.18 — 6 wt % 4 wt % — — 2.78 Up to 17 wt % N/A

[0170] The data of table 4 shows that ZnS particles capped with MPhO, PhS, Me or a mixture of PhS and Me can be homogeneously dispersed in relatively high amounts (up to 20 wt %) in 3PA or 3PMA monomer composition.

[0171] The polymerizable composition was applied between two glass plates separated by a spacer of 200 μm. Photopolymerization was performed after addition of a radical photoinitiator (Irgacure184, BASF) and illumination with a Hg lamp during 10 min (4 mW.Math.cm.sup.−2). Photopolymerization was induced between two glass substrates to avoid the inhibition by oxygen. A Teflon spacer of 200 μm was used between the two glass substrates. The resulting thickness of the cured material was 220 μm.

[0172] Haze was measured after demolding with a spectrophotometer UV-Vis (Hitachi U-4100) according to Japanese Industrial Standard No 7136-2000.

[0173] 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 5.

TABLE-US-00006 TABLE 5 Refractive index of 3PA + coated particles ZnS Refractive index (220 μm) of 3PA [20 wt % of Wavelength (180 μm) particles] δ n ZnS PhS 654 nm 1.505 1.551 0.046 ME 594 nm 1.508 1.554 0.046 0.3:0.6 473 nm 1.516 1.566 0.05 Abbe number 52 41 T (400 nm)   86%  80% Haze 392 nm 0.31% 4.5% 436 nm 0.27% 4.2% 544 nm 0.25% 4.0% 653 nm 0.25% 3.8%

[0174] The data of table 5 shows that the refractive index of the polymer containing 20 wt % of coated ZnS particles is increased by 0.05 at 473 nm compared with the same polymer without particles.

[0175] Furthermore, the data of table 5 shows that the composite material is suitable for optical materials (haze below 5%).

3) Preparation of Liquid Polymerizable Composition Comprising ZrO2 Nanoparticles Dispersed in a Phosphine Oxide Containing Monomer.

[0176] Five compositions were prepared by adding to the phosphine oxide monomer 1 (marketed by Osaka Organic Chemicals under the commercial name Viscoat 3-PA®) 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.

[0177] Then, each composition was applied between two glass plates separated by a spacer of 500 μm. Photopolymerization was performed by illumination with a Hg lamp during 10 min (4 mW.Math.cm.sup.−2). Photopolymerization was induced between two glass substrates to avoid the inhibition by oxygen. A Silicon spacer of 500 μm was used between the two glass substrates.

[0178] The refractive index and Haze were measured as for example 2.

[0179] The refractive indexes at 594 nm, Abbe numbers and haze of the resulting materials are indicated in Table 6.

TABLE-US-00007 TABLE 6 Optical properties 0 wt % l0 wt % 20 wt % 30 w t% 40□wt % 50□wt % 594 nm 1.506 1.520 1.539 1.555 1.569 1.592 δn — 0.014 0.033 0.049 0.063 0.086 Abbe Number 57 51 48 52 46 45 T (400 nm)  86%  85%  75%  75%  71%  77% Haze 0 wt % l0 wt % 20 wt % 30 w t% 40 wt % 50 wt % 392 nm 0.31% 0.95% 1.3% 1.3% 2.1% 3.8% 436 nm 0.27% 0.86% 1.2% 1.2% 1.9% 3.5% 544 nm 0.25% 0.75% 1.0% 1.0% 1.5% 3.1% 653 nm 0.25% 0.70% 0.92% 0.94% 1.3% 2.8%

[0180] The data of table 6 shows that the refractive index of the polymer may be increased by 0.086 at 594 nm with the addition of 50 wt % of ZrO.sub.2 nanoparticles compared with the same polymer without nanoparticles.

[0181] Furthermore, the data of table 6 shows that the composite material is suitable for optical materials (haze below 5%).

[0182] In table 7 below, materials obtained according to the above described method from a composition containing 3-PA and 20 wt % of ZrO2 nanoparticles or 20 wt % of Zns nanoparticles coated with 0.3:0.6 PhS:ME are compared.

TABLE-US-00008 TABLE 7 20 wt % 20 wt % Optical properties 3-PA coated ZnS ZrO2 thickness 500 μm 220 μm 500 μm 594 nm 1.506 1.554 1.539 δn — 0.046 0.033 Abbe Number 57    41 48 T (400 nm) 91% 80% 75% 20 wt % 20 wt % Haze 3-PA coated ZnS ZrO2 Thickness 500 μm 220 μm 500 μm 392 nm 0.31% 4.5% 1.3% 436 nm 0.27% 4.2% 1.2% 544 nm 0.25% 4.0% 1.0% 653 nm 0.25% 3.8% 0.92%

[0183] The data of table 7 shows that the increase of the refractive index of the polymer is higher with ZnS nanoparticles than with ZrO.sub.2 nanoparticles.

4) Preparation of Liquid Polymerizable Composition Comprising TiO.SUB.2 .Nanoparticles Dispersed in a Phosphine Oxide Containing Monomer.

[0184] Three compositions were prepared by adding to the phosphine oxide monomer 1 (marketed by Osaka Organic Chemicals under the commercial name Viscoat 3-PA®) respectively 10 wt %, 20 wt % and 30 wt % of TiO.sub.2 from a suspension of TiO.sub.2/MeOH (15 wt % in MeOH, commercially available from Sakai chemical), and then adding to this mixture 1 wt % of Irgacure 184 (a radical photoinitiator marketed by BASF). The methanol of the resulting composition was evaporated under reduced pressure.

[0185] Then, each composition was applied between two glass plates separated by a spacer of 500 μm. Photopolymerization was performed by illumination with a Hg lamp during 10 min (1.7 J.Math.cm.sup.−2). A silicon spacer of 500 μm was used between the two glass substrates.

[0186] The refractive index and Haze were measured as for example 2.

[0187] The refractive indexes at 594 nm, Abbe numbers and front scattering of the resulting materials are indicated in Table 8.

TABLE-US-00009 TABLE 8 Optical properties 0 wt % 10 wt % 20 wt % 30 wt % 594 nm 1.506 1.524 1.566 1.617 δn — 0.018 0.006 0.111 Abbe Number 57 44 33 27 T (400 nm) 86% 23% 1% 1%

[0188] In table 9 below, materials obtained according to the above described method from a composition containing 3-PA and 30 wt % of ZrO.sub.2 nanoparticles or 30 wt % of TiO.sub.2 nanoparticles are compared.

TABLE-US-00010 TABLE 9 30 wt % ZrO2 TiO2 594 nm 1.555 1.617 δn 0.049 0.111 Abbe Number 52 27 T (400 nm) 75% 1%

[0189] The data of table 9 show that the transmission of a 3PA material containing TiO2 nanoparticles is much lower than the transmission of the same material comprising ZrO2 nanoparticles. However, it is to be noted that the particle size of TiO2 used to prepare this material is higher than the particle size of ZrO2. Thus, the transmission of a 3-PA composition containing TiO2 nanoparticles should be increased by using TiO2 nanoparticles of lower particle size and by choosing a monomer having a higher refractive index than 3-PA.