Heat-curable hybrid epoxy functional composition and transparent heat-cured caustic-resistant coatings prepared therefrom

Abstract

The present invention relates to a heat-curable composition comprising at least one epoxy monomer comprising two or three epoxy groups, which is not a hydrolysis-polymerizable silicon compound, at least one epoxy compound bearing at least one silicon atom having at least one hydrolyzable group directly linked to the silicon atom and at least one epoxy group, and at least one epoxy ring-opening catalyst. The composition comprises at least 50% by weight of compounds having at least one epoxy group, relative to the total weight of polymerizable compounds present in the composition and provides upon pre-curing a tack-free coating that can be removed by treatment with a solution of sodium hydroxide, and upon post-curing a coating that cannot be removed by treatment with a solution of sodium hydroxide.

Claims

1. A heat-curable composition comprising: (a) at least one epoxy monomer having two or three epoxy groups, which is not a silicon compound having at least one hydrolyzable group directly linked to the silicon atom; (b) at least one epoxy compound bearing at least one silicon atom having at least one hydrolyzable group directly linked to the silicon atom and at least one group comprising an epoxy function linked to the silicon atom through a carbon atom, and/or a hydrolyzate thereof; and (c) at least one epoxy ring-opening catalyst; wherein: the composition comprises at least 50% by weight of at least one compound having at least one epoxy group, relative to the total weight of polymerizable compounds present in the composition; and the heat-curable composition provides: upon heating to a temperature ranging from 60° C. to less than 90° C., a tack-free coating that can be removed by treatment with a 10% wt. solution of sodium hydroxide; and upon heating to a temperature ranging from 90° C. to 140° C., a coating that cannot be removed by treatment with a 10% wt. solution of sodium hydroxide the composition further comprising at least one organic solvent selected from glycol monoethers, the ratio: dry extract weight of monomers (a) and (d) (if present)/dry extract weight of compound (b) ranges from 97/3 to 50/50, where a monomer (d) is an epoxy monomer comprising from 4 to 8 epoxy groups that is not a silicon compound having at least one hydrolyzable group directly linked to the silicon atom; and wherein the composition comprises from 30 to 55% by weight relative to the total weight of the composition of monomers (a), (d) (if present) and compound (b) and from 35 to 65% by weight of at least one organic solvent selected from glycol monoethers, relative to the total weight of the composition.

2. The composition of claim 1, wherein the composition comprises at least 60% by weight of at least one compound having at least one epoxy group, relative to the total weight of polymerizable compounds present in the composition.

3. The composition of claim 1, wherein the composition comprises at least 75% by weight of at least one compound having at least one epoxy group, relative to the total weight of polymerizable compounds present in the composition.

4. The composition of claim 1, wherein the composition is devoid of any non-epoxy functional monomers.

5. The composition of claim 1, wherein the weight ratio: monomers (a)/monomers (d) ranges from 100/0 to 50/50, where a monomer (d) is an epoxy monomer comprising from 4 to 8 epoxy groups that is not a silicon compound having at least one hydrolyzable group directly linked to the silicon atom.

6. The composition of claim 1, wherein the epoxy groups of monomer (a) and compound (b) are chosen from glycidyl groups and cycloaliphatic epoxy groups.

7. The composition of claim 1, wherein compound (b) is a compound of formula:
R.sub.n′Y.sub.mSi(X).sub.4-n′-m  (II) in which the R groups are identical or different and represent monovalent organic groups linked to the silicon atom through a carbon atom and that do not contain any epoxy group, the Y groups are identical or different and represent monovalent organic groups linked to the silicon atom through a carbon atom and contain at least one epoxy group, the X groups are identical or different and represent hydrolyzable groups or hydrogen atoms, m and n′ are integers such that m is equal to 1 or 2 and n′+m=1 or 2.

8. The composition of claim 1, comprising from 1 to 30% by weight of compound (b) relative to the total weight of the composition.

9. The composition of claim 1, comprising monomer (d).

10. An optical article comprising a substrate having at least one main surface bearing a coating resulting from the heat-curing of a heat-curable composition of claim 1.

11. The optical article of claim 10, further defined as an optical lens.

12. The optical article of claim 10, further defined as an ophthalmic lens.

13. A method for preparing the optical article of claim 10, comprising: (i) depositing on the substrate of the optical article a heat-curable composition of claim 1; (ii) heating the optical article coated with said heat-curable composition to a temperature higher than or equal to 60° C. so as to form a tack-free coating; and (iii) heating the optical article coated with said tack-free coating to a temperature higher than or equal to the temperature of step (ii) so as to obtain a completely cured coating.

14. The composition of claim 1, wherein compounds (d) represent from 1 to 10% of the weight of the composition.

15. The composition of claim 1, wherein the ratio: dry extract weight of monomers (a) and (d) (if present)/dry extract weight of compound (b) ranges from 96/4 to 60/40, where a monomer (d) is an epoxy monomer comprising from 4 to 8 epoxy groups that is not a silicon compound having at least one hydrolyzable group directly linked to the silicon atom.

16. A heat-curable composition comprising: (a) at least one epoxy monomer having two or three epoxy groups, which is not a silicon compound having at least one hydrolyzable group directly linked to the silicon atom; (b) at least one epoxy compound bearing at least one silicon atom having at least one hydrolyzable group directly linked to the silicon atom and at least one group comprising an epoxy function linked to the silicon atom through a carbon atom, and/or a hydrolyzate thereof; (c) at least one epoxy ring-opening catalyst; and (d) at least one epoxy monomer comprising from 4 to 8 epoxy groups that is not a silicon compound having at least one hydrolyzable group directly linked to the silicon atom; wherein: the composition comprises at least 50% by weight of at least one compound having at least one epoxy group, relative to the total weight of polymerizable compounds present in the composition; and the heat-curable composition provides: upon heating to a temperature ranging from 60° C. to less than 90° C., a tack-free coating that can be removed by treatment with a 10% wt. solution of sodium hydroxide; and upon heating to a temperature ranging from 90° C. to 140° C., a coating that cannot be removed by treatment with a 10% wt. solution of sodium hydroxide the composition further comprising at least one organic solvent selected from glycol monoethers, the ratio: dry extract weight of monomers (a) and (d)/dry extract weight of compound (b) ranges from 97/3 to 50/50.

17. The composition of claim 1, wherein compound (d) represents from 2 to 6% of the weight of the composition.

Description

EXAMPLES

(1) The optical articles used in the examples comprise an ORMA® lens substrate from ESSILOR, having a 65 mm diameter, a refractive index of 1.50, a power of −2.00 diopters and a thickness of 1.2 mm.

(2) Various coating compositions of epoxy copolymers were prepared and are shown in the tables below. The compositions comprise at least one non silicon-containing bi- or tri-functional epoxy monomer comprising two or three epoxy groups (compound (a)), γ-glycidoxypropyltrimethoxysilane (from Evonik Industries) or 3-glycidoxypropyl methyldiethoxysilane (KBE-402® from Shin-Etsu Silicone), as compound (b) pre-hydrolyzed with 0.10 N HCl, a Lewis acid polymerization catalyst for the epoxy groups (compound (c): Nacure® Super XC-A218, metal salt of triflic acid in n-butanol, 25% wt., from King Industries or Nacure® Super XC-7231, ammonium hexafluoroantimonate from King Industries), a surfactant (EFKA® 3034, which is a fluorocarbon containing organically modified polysiloxane, 50-53% wt. in methoxypropanol, sold by CIBA, or Novec® FC-4434, which is a non ionic surfactant comprising fluoroaliphatic polymeric esters, 25% wt. in dipropylene glycol monomethyl ether, sold by 3M), propylene glycol methyl ether (Dowanol® PM from Dow Chemical Company) and optionally propylene carbonate as a solvent.

(3) The following non silicon-containing bi- or tri-functional epoxy monomers comprising two or three epoxy groups were investigated (compounds (a)): Erisys™ GE-30 (trimethylolpropane triglycidyl ether, abbreviated as GE-30, from CVC thermoset Specialties) and UVACure® 1500 (3′,4′-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, cycloaliphatic diepoxy compound from Allnex USA Inc.).

(4) The following non silicon-containing polyfunctional epoxy monomer comprising from 4 to 8 epoxy groups was used in some examples (compound (d)): Erisys™ GE-60 (sorbitol hexaglycidyl ether, abbreviated as GE-60, from CVC thermoset Specialties).

(5) Other optional compounds can be included in some compositions, such as colloidal silica (MA-ST-HV® from Nissan Chemical, 30% wt. dispersion in methanol, example 20), and dyes.

(6) The structures of some of the various epoxy compounds that have been used are recalled hereunder:

(7) TABLE-US-00001 Epoxy compound Glymo KBE-402 ® Erisys ™ GE-30 Structure Epoxy UVACure ® compound Erisys ™ GE-60 1500 Structure 0

(8) Evaluation of the Coating Performances

(9) a) A dry adhesion test, referred to as a crosshatch tape peel adhesion test, was performed on coated articles in accordance with IS™ 02-010, using 3M SCOTCH® n° 600 transparent tape, such as disclosed in U.S. Pat. No. 7,476,415 and US 20140037964, after they have been subjected to a Q-Sun test. The Q-sun test consists in introducing the prepared lenses 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 their convex side to the light for 40 h or 80 h.

(10) b) Abrasion resistance and haze were determined as disclosed in WO 2012/173596. Specifically, abrasion resistance was measured by means of the sand Bayer test, in accordance with the ASTM F735-81 standard. Haze was measured on a Haze-Gard XL-211 Plus apparatus from BYK-Gardner in accordance with the standard ASTM D1003-00. As haze is a measurement of the percentage of transmitted light scattered more than 2.5° from the axis of the incident light, the smaller the haze value, the lower the degree of cloudiness. Generally, for optical articles described herein, a haze value of less than or equal to 0.3% is acceptable, more preferably of less than or equal to 0.2%.

(11) c) The light transmission factor in the visible spectrum Tv was measured in transmission mode (incidence angle: 0°) from a wearer's view angle using a Cary 4000 spectrophotometer from Hunter, 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).

(12) Preparation, Deposition and Curing of the Coating Compositions

(13) Epoxy compounds (a) and (d) (when present) were mixed in a Nalgene container. The solvent (Dowanol® PM) was added and the solution was allowed to stir for 60 minutes. The surfactant was added and the mixture allowed to mix for 60 more minutes.

(14) Compound (b), typically glymo, was mixed with 0.1N HCl for 0.5-1 hrs, and then added to the other ingredients. An ultrasonication or agitation process was sometimes added to obtain more uniform solutions.

(15) In the coatings utilizing the blocked and buffered catalysts from King Industries, the catalyst was added after mixing the epoxies, solvent and optional dyes together and before adding the hydrolyzed Glymo. In the coatings utilizing Al(AcAc).sub.3, the catalyst was added last (after adding the hydrolyzed Glymo to the epoxy/solvent/dye mixture).

(16) Each of the coating solutions was deposited by spin coating onto a cleaned face of an Orma® lens previously cleaned with diluted NaOH (500 rpm for 5 s, then 1000 rpm for 10 s, all examples except examples 6 and C1, C2), or by dip coating both faces of such lens in the coating composition (at a withdrawal speed of 2.5 mm/s, examples 6 and C1, C2). A pre-curing step at 75-80° C. generally for 15 minutes followed by a post-curing step at 100-110° C. for 3 hours were then performed. The (dry) coating thicknesses were ˜5 μm (examples 6, C1, C2) or ˜8 μm (in the other examples).

(17) The results are shown in the tables below.

(18) TABLE-US-00002 Example 1 2 3 4 5 Epoxy (d)GE-60 2.38 2.72 2.89 3.06 3.23 compound (%) (a)GE-30 4.83 5.52 5.865 6.21 6.555 (%) (a) 19.67 22.48 23.885 25.29 26.695 UVACure ® 1500 (%) (b)Glymo 24.41 16.28 12.21 8.14 4.07 (%) (c)Nacure ® Super 3.85 4.4 4.675 4.95 5.225 XC-A218 (%) EFKA ® 3034 (%) 0.07 0.08 0.085 0.09 0.095 Dowanol ® PM (%) 39.2 44.8 47.6 50.4 53.2 HCl 0.1N (%) 5.59 3.72 2.79 1.86 0.93 After heating 15 Tack-free Tack-free Tack-free Tack-free Tack-free min at 80° C. Removable by Removable by Removable by Mostly Mostly 10% NaOH (8 10% NaOH (8 10% NaOH (8 removable by removable by min at 60° C.) min at 60° C.) min at 60° C.) 10% NaOH (8 10% NaOH (8 min at 60° C.) min at 60° C.) After heating 3 Non- Non- Non-removable by Non-removable Non-removable by hours at 110° C. removable by removable by 10% NaOH (8 by 10% NaOH 10% NaOH (8 10% NaOH (8 10% NaOH (8 min at 60° C.) (8 min at 60° C.) min at 60° C.) min at 60° C.) min at 60° C.)

(19) TABLE-US-00003 C1 C2 Example 6 7 8 (comparative) (comparative) Epoxy (d)GE-60 2.41 2.35 2.29 30.6 3.4 compounds (%) (a)GE-30 4.89 4.77 4.66 7.1 6.9 (%) (a)UVACure ® 19.90 19.42 18.96 0 28.1 1500 (%) (b)Glymo 10.19 11.94 13.60 0 0 (%) (c)Nacure ® Super 3.90 3.80 3.71 5.7 5.5 XC-A218 (%) EFKA ® 3034 (%) 0.07 0.07 0.07 0.1 0.1 Dowanol ® PM (%) 56.33 54.96 53.65 56.6 56.0 HCl 0.1N (%) 2.30 2.69 3.07 0 0 After heating 15 Tack-free Tack-free Tack-free Tack-free Tack-free min at 75° C. Removable by Removable by Removable by Non- Non- (80° C. for 10% NaOH (4 10% NaOH (4 10% NaOH (4 removable by removable by examples C1, C2) min at 60° C.) min at 60° C.) min at 60° C.) 10% NaOH 10% NaOH (30 min at (30 min at 60° C.) 60° C.) After heating 3 Non- Non- Non- Non- Non- hours at 110° C. removable by removable by removable by removable by removable by (100° C. for 10% NaOH (8 10% NaOH (4 10% NaOH (4 10% NaOH 10% NaOH examples C1, C2) min at 60° C.) min at 60° C.) min at 60° C.) (30 min at (30 min at 60° C.) 60° C.)

(20) TABLE-US-00004 Example 9 10 11 12 13 Epoxy (d)GE-60 2.53 2.52 2.50 2.50 2.49 compounds (%) (a)GE-30 5.13 5.11 5.08 5.07 5.05 (%) (a)UVACure ® 20.87 20.81 20.68 20.62 20.56 1500 (%) (b)Glymo 5.26 5.49 5.96 6.18 6.41 (%) (c)Nacure ® Super 5.85 5.83 5.79 5.77 5.76 XC-7231 (%) EFKA ® 3034 (%) 0.07 0.07 0.07 0.07 0.07 Dowanol ® PM (%) 59.09 58.90 58.55 58.37 58.19 HCl 0.1N (%) 1.20 1.26 1.36 1.42 1.47 After heating 15 Tack-free Tack-free Tack-free Tack-free Tack-free min at 75° C. Removable by Removable by Removable by Removable by Removable by 10% NaOH (8 10% NaOH (8 10% NaOH (8 10% NaOH (8 10% NaOH (8 min at 60° C.) min at 60° C.) min at 60° C.) min at 60° C.) min at 60° C.) After heating 3 Non- Non- Non- Non- Non- hours at 100° C. removable by removable by removable by removable by removable by 10% NaOH (8 10% NaOH (8 10% NaOH (8 10% NaOH (4 10% NaOH (4 min at 60° C.) min at 60° C.) min at 60° C.) min at 60° C.) min at 60° C.)

(21) TABLE-US-00005 Example 14 15 16 17 18 Epoxy (d)GE-60 2.66 2.62 2.57 2.57 2.52 compounds (%) (a)GE-30 5.39 5.32 5.22 5.21 5.12 (%) (a)UVACure ® 21.94 21.64 21.25 21.20 20.83 1500 (%) (b)Glymo 4.88 5.92 7.27 7.24 8.55 (%) (c)Nacure ® Super 1.84 1.82 1.78 2.05 2.01 XC-7231 (%) EFKA ® 3034 (%) 0.08 0.08 0.07 0.07 0.07 Dowanol ® PM (%) 62.10 61.26 60.16 60.00 58.95 HCl 0.1N (%) 1.12 1.35 1.66 1.66 1.95 After heating 20 Tack-free Tack-free Tack-free Tack-free Tack-free min at 80° C. Partially Partially Removable by Removable by Removable by removable by removable by 10% NaOH (8 10% NaOH (4 10% NaOH (4 10% NaOH (4 10% NaOH (4 min at 60° C.) min at 60° C.) min at 60° C.) min at 60° C.) min at 60° C.) After heating 3 Non- Non- Non- Non- Non- hours at 100° C. removable by removable by removable by removable by removable by 10% NaOH (8 10% NaOH (8 10% NaOH (8 10% NaOH (8 10% NaOH (4 min at 60° C.) min at 60° C.) min at 60° C.) min at 60° C.) min at 60° C.)

(22) TABLE-US-00006 Example 19 20 Epoxy (d) GE-60 2.42 2.55 compounds (%) (a) GE-30 4.90 5.18 (%) (a)UVACure ® 19.95 21.08 1500 (%) (b)Glymo 10.53 4.9 (%) (b) KBE-402 ® (%) 0 2.6 Colloidal silica (%) 0 15.8 (c) Nacure ®Super 0.32 4.13 XC-A218 (%) (c) Nacure ® Super 2.77 0 XC-7231 (%) EFKA ® 3034 (%) 0 0.08 Novec ® FC-4434 0.19 0 (%) Dowanol ® PM (%) 56.45 42 HCl 0.1N (%) 2.41 1.7 After heating 15 Tack-free Tack-free min at 75° C. (80° C. Removable by Removable by for example 19) 10% NaOH (8 10% NaOH (4 min at 60° C.) min at 60° C.) After heating 3 Non- Non- hours at 110° C. removable by removable by (100° C. for 10% NaOH (4 10% NaoH (4 example 19) min at 60° C., 3 min at 60° C.) times)

(23) TABLE-US-00007 Example 21 22 23 24 25 Epoxy (d)GE-60 2.50 4.00 5.00 6.00 0 compounds (%) (a)GE-30 5.00 8.00 10.00 12.00 15.09 (%) (a)UVACure ® 20.00 15.50 12.50 9.50 10.48 1500 (%) (b)Glymo 10.58 10.58 10.58 10.58 10.36 (%) (c)Nacure ® Super 2.70 2.70 2.70 2.70 0 XC-7231 (%) (c)Al(AcAc).sub.3 (%) 0 0 0 0 0.47 Novec ® FC-4434 0.20 0.20 0.20 0.20 0.20 (%) Dowanol ® PM (%) 51.20 51.20 51.20 51.20 56.87 Propylene 5.40 5.40 5.40 5.40 0 carbonate (%) Methanol (%) 0 0 0 0 4.17 HCl 0.1N (%) 2.42 2.42 2.42 2.42 2.37 Heating time at 18 min 22 min 23 min 25 min 8 min 90° C. (75° C. for example 25) required to tack- free state After heating 3 Non- Non- Non- Non- Non-removable hours at 100° C. removable by removable by removable by removable by 10% NaOH 10% NaOH 10% NaOH 10% NaOH by 10% NaOH (4 min at 60° C., (4 min at (4 min at (4 min at (4 min at 2 times) 60° C., 1 time) 60° C., 3 times) 60° C., 3 times) 60° C., 3 times)

(24) TABLE-US-00008 C3 C4 C5 Example 26 27 (comparative) (comparative) (comparative) Epoxy (a)UVACure ® 30.73 29.89 29.10 28.35 27.50 compounds 1500 (%) (b)Glymo 2.27 4.42 6.46 8.39 10.58 (%) (c)Nacure ® 3.02 2.94 2.86 2.78 2.70 Super XC-7231 (%) Novec ® FC- 0.22 0.22 0.21 0.21 0.20 4434 (%) Dowanol ® PM 57.21 55.65 54.18 52.78 51.20 (%) Propylene 6.03 5.90 5.71 5.57 5.40 carbonate (%) HCl 0.1N (%) 0.52 1.01 1.48 1.92 2.42 After heating Tack-free Tack-free Tack-free Tack-free Tack-free 15 min at 90° C. After heating 3 Non- Non- Partially Partially Removable by hours at 100° C. removable by removable by removable by removable by 10% NaOH (4 10% NaOH 10% NaOH 10% NaOH (4 10% NaOH (4 min at 60° C. 1 (4 min at (4 min at min at 60° C., 1 min at 60° C., 1 time) 60° C., 3 60° C., 2 time): 60% of time): 80% of times) times) the surface is the surface is removed removed

(25) After pre-curing at 75-90° C. for 15 min, the coatings according to the invention were tack-free and removable (strippable) from the lenses, generally totally removable, after soaking in a soda solution (NaOH, 10 wt. %) under ultrasonication at 60° C. for 4 or 8 minutes (ultrasonication was used for each removal treatment with NaOH, such as the ultrasonication provided by a D645 dip coating machine).

(26) After post-curing at 100-110° C. for 3 hrs, the coatings exhibited low haze (˜0.1%), good transmittance (Tv-92%), good adhesion after 80 h Q-sun exposure and/or caustic treatment and good abrasion resistance (Sand Bayer values for examples C2, 6 and 20 were respectively 0.8, 1,13 and 1.3).

(27) The post-cured coatings were caustic resistant, which means that they could not be removed from the lenses after cleaning in a soda solution (NaOH, 10 wt. %) under ultrasonication at 60° C. for at least 4 minutes.

(28) A comparison of examples 1-8 with examples C1 and C2 reveals that the presence in the composition of an organic silicon compound having at least one hydrolyzable group directly linked to the silicon atom and at least one epoxy group (compound (b)) allows to obtain a coating that is removable after a treatment with 10% NaOH at 60° C., preferably with a treatment time of not more than 8 minutes. The coatings in examples C1 and C2 were caustic resistant after pre-curing since they could not be removed by 10% NaOH, even after an extended treatment of 30 min at 60° C.

(29) The examples show that the epoxy coating compositions can be cured by using various catalysts. The amount of hydrolyzed epoxy-silane needed to maintain caustic resistance after post-cure with the ability to strip the coating after pre-cure is dependent on the catalyst nature and concentration.

(30) Adding a small amount of the latent catalyst Nacure® Super XC-A218 to the blocked catalyst Nacure® Super XC-7231 (such as in example 19) allowed improved processing time and composition stability over a composition containing exclusively the blocked catalyst, for thicker optical articles (data not shown). The latent catalyst allowed the coating to pre-cure at a lower temperature and in a shorter time, while the blocked catalyst reacted well at the higher post-cure temperature. Using only the minimum amount of the latent catalyst ensured the longest stability and pot-life of the coating composition.

(31) A comparison of examples 9-13 on one hand and examples 14-18 on the other hand shows that by increasing the pre-cure temperature from 75° C. to 80° C. and time from 15 to 20 minutes, the amount of catalyst needed to obtain a tack-free coating was divided by more than 2, which significantly reduces the coating production costs.

(32) It was found that other epoxy silanes with or without colloidal silica could be added while retaining the removability characteristics, low haze, good transmittance, good adhesion and improved abrasion resistance (example 20).

(33) A coating composition using exclusively a metal chelate catalyst, Al(AcAc).sub.3, was able to be quickly pre-cured at low temperature to a tack-free state (example 25, 8 min at 75° C.) and the coating to be stripped in as little as 8 minutes with 10% wt. NaOH at 60° C.

(34) As seen in examples 21 through 24, increasing the glycidyl ether epoxy concentrations (GE-30 and GE-60), while decreasing the cycloaliphatic epoxy concentration (UVACure® 1500), increased the pre-cure time needed to obtain a tack-free state. By removing the glycidyl ether containing epoxy compounds, it was possible to reduce the pre-cure time needed to obtain a tack-free state to 15 minutes at 90° C. (examples 26, 27). The amount of hydrolyzed epoxysilane needed for stripping after pre-cure could be dramatically reduced while maintaining caustic resistance after post-curing.

(35) Comparative examples C3-C5 show that a composition containing a too high amount of compound (b) leads to a coating that can be partially or totally removed by a 10% wt. solution of sodium hydroxide after post-cure.

(36) The above examples correspond to epoxy coatings directly deposited onto a lens, without surrounding coatings (configuration 1: lens/epoxy coating).

(37) Other coating configurations were also tested to show that the present epoxy coatings can be used as intermediate functional layers in different coating configurations and maintain or improve general coating performances such as mechanical performances:

(38) Configuration 2: lens/epoxy coating/primer coating/hard coat.

(39) Configuration 3: lens/polyurethane reactive coating/epoxy coating/primer coating/hard coat.

(40) Reference configuration: lens/primer coating/hard coat.

(41) The epoxy coating used to compare the different configuration was that of example 6. The primer (polyurethane) and hard coat (polysiloxane) were those used in the examples of WO 2013/013929. The polyurethane reactive coating was that used in the examples of U.S. Pat. No. 6,187,444 and WO 2011/075128, with or without photochromic dyes.

(42) TABLE-US-00009 Configuration Reference 2 3 ASTM haze (%) 0.1 0.1 0.1 Adhesion after Q-sun Good Good Good 80 h Sand Bayer 3.1 3.5-3.7 4.1