Optical article comprising an external water- and/or oil-repellent coating coated with a temporary coating

The invention relates generally to the field of optical articles, in particular ophthalmic lenses, provided with an external coating with a hydrophobic and / or oleophobic property (top coat).

These hydrophobic and / or oleophobic outer coatings are well known in the art.

These hydrophobic and / or oleophobic external coatings, which are generally associated with anti-reflection coatings, are intended to make the ophthalmic lens less messy. It is most often a material of the fluorosilane type which reduces the surface energy in order to prevent the adhesion of oily soils which are thus easier to remove.

One of the problems generated by these hydrophobic and / or oleophobic external coatings is that they achieve an efficiency such as the adhesion to the interface of an adhesive pad / surface of the hydrophobic and / or oleophobic coating necessary for mounting the lenses during application. 'an overflowing operation is thereby altered or even compromised.

Edging is the last step in finishing an ophthalmic lens and is the operation of machining the edge or periphery of the lens to conform it to the dimensions and shape required to fit the lens to the spectacle frame. in which it is intended to take place.

The edging is carried out on an automated grinder comprising diamond grinding wheels which perform the machining defined above and it is therefore necessary to hold the lens to be edged in the grinder fixedly.

To do this, the first phase is to attach an acorn to the center of the convex surface of the lens by means of an adhesive pad such as a double-sided adhesive pad.

The glans to which the lens adheres by means of the adhesive pad is then mechanically fixed in the mounting axis of the grinder and an axial arm blocks the lens by applying a central force on the face of the lens opposite the glans.

During edging, the lens should not undergo an offset greater than 2 °, preferably no more than 1 °, and therefore the adhesion of the pad to the lens surface is essential to obtain an edging. satisfactory.

To remedy these difficulties of edging lenses provided with a hydrophobic and / or oleophobic outer coating, it has been proposed to form on these hydrophobic and / or oleophobic coatings a temporary coating, of organic or inorganic nature. For example, European patent applications EP 1 392 613 and EP 1 633 684, in the name of ESSILOR, describe the use of a temporary coating, of organic or inorganic nature, which increases the surface energy and therefore allows the optician to perform a reliable edging of the lens. After edging, the temporary coating must be removed in order to restore the hydrophobic and / or oleophobic outer coating to its surface properties. It goes without saying that after removal of the temporary coating, the hydrophobic and / or oleophobic outer coating must exhibit surface properties as close as possible to its initial properties.

Although the temporary coatings described in European patent applications EP 1 392 613 and EP 1 633 684 lead, after their removal, to hydrophobic and / or oleophobic external coatings having good surface properties and a static contact angle with the High water (typically 112 °), it is desirable to further increase this contact angle value.

Where appropriate, after the main edging operation of the optical article, it may be desirable to carry out an edging recovery operation, and / or a drilling of the lens, the pierced area serving as a point of attachment to a branch of the lens. eyeglass frame.

For these last steps, in particular the drilling of the glass, it is fundamental that the acorn / adhesive holding pad assembly remains in position on the surface of the article, because it constitutes a reference allowing the positioning of the drills for the drilling of holes.

The film described in patent application WO 05/015 270 makes it possible to ensure the main edging, but it is systematically observed that the acorn / adhesive holding pad assembly spontaneously comes off in the seconds following this main edging operation. .

From the start of the edging operation, it seems that the water projected onto the article during this edging operation infiltrates under the temporary film which wraps around itself. Under these conditions, it is then impossible to subsequently proceed with an overflow recovery or a drilling of the glass.

Patent application WO 03/05 7641 provides for depositing an organic material on a layer of MgF₂. Therefore, the temporary film of an organic material is not deposited directly on the hydrophobic and / or oleophobic outer coating.

The object of the present invention is therefore to provide an optical article, in particular an ophthalmic lens, comprising a hydrophobic and / or oleophobic outer coating directly coated with a temporary layer which:

after removal of the temporary layer, makes it possible to recover a hydrophobic and / or oleophobic external coating having properties practically identical to its initial properties and in particular an angle of static contact with water practically equal to the angle of static contact with l initial water; and / or allows, where appropriate, an overflow recovery operation; and / or makes it possible to pierce the lens, the pierced zone serving as a point of attachment to a branch of a spectacle frame.

The objects here are achieved according to the invention by an optical article comprising on one of its main surfaces a hydrophobic and / or oleophobic outer coating of low surface energy, characterized in that a temporary layer of a latex composition of dried polyurethane is deposited directly on the hydrophobic and / or oleophobic outer coating.

The temporary, preferably peelable, layer has in general a thickness of 10 to 40 µm, preferably 15 to 30 µm and better still 15 to 20 µm and preferably exhibits an elongation at break equal to or less than 200%, better still equal to or less than 150%.

Depending on the method of depositing the temporary layer, the thickness of the layer may vary locally. In particular, in the case of deposition by dip (dipping) in a bath of liquid coating composition, the thickness is greater in the lower part of the glass (the part contacting the liquid of the temporary coating composition first. and leaving the bath last when the glass is raised).

The average thickness of the temporary layer is the average of 3 thicknesses measured at 3 points on the surface: two opposite points: high point (approximately 5 mm from the periphery of the glass), center and low point (approximately 5 mm from the periphery of the glass), in the case of deposition by dip.

The average thickness ranges are the same as the previously mentioned thickness ranges.

Preferably, the temporary layer has a surface energy greater than or equal to 15 mJ / m², better equal to or greater than 20 mJ / m², better still equal to or greater than 30 mJ / m². More preferably, the temporary layer has a polar component of the surface energy of less than 26 mJ / m².

In the present application, the term optical article denotes an organic or inorganic glass substrate, optically transparent, treated or not, depending on whether it comprises one or more coatings of various nature or whether it remains bare.

The surface energies are calculated according to the OWENSWENDT method described in the following reference: Estimation of a surface force energy of polymers OWENS DK, WENDT RG (1969) J. Appl. POLYM. SCI, 13, 1741-1747.

The optical articles of the invention are optical articles, in particular ophthalmic lenses, which comprise a hydrophobic and / or oleophobic outer coating and preferably optical articles comprising both a hydrophobic and / or oleophobic outer coating. deposited on a single or multi-layer anti-reflective coating.

Indeed, the hydrophobic and / or oleophobic external coatings are generally applied to optical articles comprising an anti-reflection coating, in particular in mineral material, in order to reduce their marked tendency to soiling, for example vis-à-vis fatty deposits.

As is known, the hydrophobic and / or oleophobic external coatings are obtained by application, on the surface of the antireflection coating, of compounds which reduce the surface energy of the optical article.

Such compounds have been widely described in the prior art, for example in US Patents 4,410,563, EP 0 203 730, EP 749 021, EP 844

265, and EP 933 377.

Compounds based on silane bearing fluorinated groups, in particular perfluorocarbon or perfluoropolyether groups, are most often used.

By way of example, mention may be made of silazane, polysilazane or silicone compounds comprising one or more fluorinated groups as mentioned above.

A known process consists in depositing on the anti-reflection coating compounds bearing fluorinated groups and Si — R groups, R representing an —OH group or a precursor thereof, preferably an alkoxy group. Such compounds can carry out polymerization and / or crosslinking reactions on the surface of the anti-reflection coating, directly or after hydrolysis.

The application of compounds reducing the surface energy of the optical article is conventionally carried out by soaking in a solution of the compound, by centrifugation or vapor deposition, in particular.

Generally, the hydrophobic and / or oleophobic outer coating has a thickness of less than 10 nm, and more preferably less than 5 nm.

In general, the hydrophobic and / or oleophobic low surface energy outer coating has a surface energy of 14 mJ / m or less.², preferably equal to or less than 13 mJ / m², better equal to or less than 12 mJ / m².

As indicated above, the temporary layer of the invention is a dried layer of a polyurethane latex composition deposited directly on the hydrophobic and / or oleophobic outer coating.

As is well known, a latex is a dispersion in an aqueous medium of polymer or copolymer particles. The aqueous medium can be water, for example distilled water or deionized water, or else a mixture of water and one or more solvents, in particular water and alkanol, generally a C1 to C6 alkanol, and preferably ethanol.

In the present invention, the term polyurethane encompasses both the polyurethane (co) polymers proper, that is to say the polymers obtained by condensation of at least one polyisocyanate and at least one polyol and optionally of 'a chain extender, and polyurethane-urea, that is to say the (co) polymers obtained by condensation of at least one polyisocyanate and of a polyamine, and optionally of a chain extender, and mixtures of these.

Preferably, the polyurethanes and polyurethane-urea of ​​the invention result from the condensation of a diisocyanate with a diol and / or a diamine. More preferably, the polyurethanes and polyurethane-urea of ​​the invention are linear or cyclic aliphatic polyurethanes and polyurethane-urea, that is to say obtained by condensation of linear or cyclic aliphatic polyisocyanates with polyols and / or polyamines linear or cyclic aliphatics.

Among the polyisocyanates useful for forming the polyurethanes and polyurethane-urea of ​​the invention, and in particular the preferred diisocyanates, mention may be made of toluene-2,4-diisiocyanate, toluene -2,6-diisocyanate, diphenylmethane-4, 4'-diisocyanate, diphenylmethane-2,4'-diisocyanate, paraphenylene diisocyanate, biphenyl diisocyanate, 3,3'-dimethyl-4,4'diphenylene diisocyanate, tetramethylene-1,4-diisocyanate, hexamethylene -1,6-diisocyanate, 2,2,4-trimethylhexane-1,6-diisocyanate, lysinemethyl ester diisocyanate, bis (isocyanoethyl) fumarate, isophorone diisocyanate (IPDI), ethylene diisocyanate, dodecane-1,12diisocyanate, cyclobutane-1 , 3-diisocyanate, diisocyanate, cyclohexane-1,4-diisocyanate, diisocyanate, hexahydrotoluene-2,4-diisocyanate, cyclohexane-1,3methylcyclohexyl methylcyclohexyl diisocyanate, hexahydrotoluene-2,4-diisocyanate, cyclohexane-1,3methylcyclohexyl methylcyclohexyl diisocyanate, hexahydrotolisocuène-2,4 2,6-hexahydrotoluene diisocyanate, hexahydrophenylene-1,3-diisocyanate, hexahydrophenylene-

1,4-diisocyanate, perhydrodyphenylmethane-2,4'-diisocyanate, perhydrodiphenylmethane-2,4'-diisocyanate, perhydrodiphenylmethane

2,4'-diisyocanate, perhydrophenylmethane-4,4'-diisocyanate (or bis- (4 isocyanatocyclohexil) -methane, or 4,4'-dicyclohexilomethane diisocyanate) and mixtures thereof.

Preferred polyisocyanates are aliphatic diisocyanates such as hexamethylene-1,6-diisocyanate, isophorone diisocyanate, ethylene diisocyanate, dodecane-1,12-diisocyanate, cyclohexane-1,3 diisocyanate, bis- ( 4-isocyanato-cyclohexyl) -methane and mixtures thereof. The preferred diisocyanate is isophorone diisocyanate.

Other polyisocyanates suitable for the polyurethanes and polyurethane-urea of ​​the invention are described in detail in document WO 98/37115.

Among the polyols suitable for the polyurethanes of the invention, mention may be made of pentaerythritol, trimethylol ethane, trimethylol propane, di (triethylol propane) dimethylol propionic acid, ethylene glycol, 1,2 and 1,3 -propylene glycol, 1,2-butanediol, 1,4-butenediol, 1,3-butanediol, 2,3-butanediol, 2,2,4-trimethyl-1,3-pentanediol, 1, 5-pentanediol,

2.4- pentanediol, 1,6-hexanediol, 2,5-hexanediol, 1,8-optanediol, 2methyl-1,3pentadiol, 2,4-heptanediol, 2-ethyl-1,3-hexanediol, 2methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol (neopentylglycol),

1.4- cyclohexanediol, 2,2-dimethyl-3-hydroxypropyl-2,2-dimethyl-3hydroxypropionate, 1,2,6-hexanetriol, 1,2,4-butanetriol, glycerol, sorbitol, manitol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, dibutylene glycol, 1,4-bis (hydroxymethyl) cyclohexane, 1,2bis (hydroxymethyl) cyclohexane, 1,2-bis (hydroxyethyl) cyclohexane, bis (hydroxypropyl) lantoins, trishydroxyethylisocyanurate.

The preferred polyols are aliphatic diols and in particular polypropylene glycol.

Another class of polyols suitable for the polyurethanes and polyurethane-urea of ​​the invention are polyether polyols such as polyoxyalkylene polyols, polyalkoxylated polyols such as poly (oxytetramethylene) diols and mixtures thereof.

The preferred polyamines are the diamines, in particular the linear and cyclic aliphatic diamines.

Among the diamines, mention may be made of diaminomethane, ethylene diamine, 1,2-diaminopropane, 1,3-diaminopropane, 1,4-diaminobutane, 1,6diaminohexane, 1,4-diaminocyclohexane, 4, 4'-diaminodicyclohexylmethane, 1-amino-3-aminomethyl-3,5,5trimétrylcyclohexane, trimethylamine.

It is also possible to use, for the preparation of polyurethanes and polyurethane-urea suitable for the invention, amino alcohols such as monoethanolamine or diethanolamine.

Polyurethanes and their method of preparation are described, inter alia, in US Pat. No. 6,187,444.

Preferably, the polyurethanes of the invention do not contain acrylic or methacrylic functions, and in particular no polymerizable acrylic or methacrylic function.

Polyurethane latexes suitable for the present invention are commercially available, for example from the company BAXENDEN under the names W 234 and W 240 (polyurethane-urea) or under the name Pellimer TC.^tm (polyurethane-urea) from SOCOMOR and PROXR 910® (polyurethane) from SYNTRON.

The Pellimer TC will be used subsequently after dilution with water. (A mixture is made consisting of 80% by weight of Pellimer TC for 20% by weight of water). This mixture obtained will be referred to hereinafter as TC80F.

The polyurethane latex compositions according to the invention can of course be mixtures of polyurethane latexes, in particular commercial polyurethane latexes.

In a particular embodiment of the invention, the polyurethane latex composition also comprises a small proportion, up to 10% by weight of the composition, of a (meth) acrylic latex, preferably of an acrylic latex. Preferably, the proportion by weight of (meth) acrylic latex varies from 0.1 to 10% by weight and better still from 2 to 6% by weight relative to the total weight of the latex composition.

The proportion by weight of dry extract of the acrylic latex relative to the total weight of dry extract of the composition also preferably varies from 0.1 to 10% by weight, and better still from 2 to 6% by weight.

The presence of (meth) acrylic latex has the advantage, on the one hand, of reducing the hydrophilic nature of the material and, on the other hand, of making the final dry layer more rigid and of reducing its elongation at break.

These (meth) acrylic latexes are commercially available in particular from the company SYNTRON under the names PROXAM 185 RS® (acrylic resin), PROXAM 157® (acrylic copolymer), PROXAM N 360® (acrylic copolymer).

Preferably, the PU latex compositions according to the invention are free from mineral or magnesium colloidal particles.

Obtaining the advantageous results of the invention, in particular the adhesion of the adhesive pad does not require the presence of inorganic or magnesium oxide colloids.

In general, the PU latex compositions according to the invention also preferably comprise one or more surfactants generally in an amount of 0.5 to 10% by weight relative to the total weight of the latex composition, preferably 0.5. at 6% by weight.

In general, the PU latex compositions according to the invention have a solid content (dry extract) of 25 to 55% by weight, preferably 25 to 50%, better still 25 to 45% by weight relative to the total weight. of the latex composition.

Their viscosity at room temperature preferably varies from 5 to 50 cp, and better still from 7 to 46 cp.

The temporary layers of the invention can be deposited on the hydrophobic and / or oleophobic coating by any type of means, but preferably by dipping (dip coating), centrifugation, spraying, or applied by means of a brush (brush coating), preferably by soaking.

The deposition can be carried out on the entire surface of the face of the lens intended to receive the adhesive holding pad or on a part thereof, in particular in the central part of the lens.

In one embodiment, the temporary layer can be applied to the central part by means of a brush.

Preferably, no other coating is placed on the surface of the temporary layer, in other words the temporary layer is preferably single-layer and during an overflow, the adhesive holding pad comes directly into contact with the surface of the temporary layer to polyurethane latex base.

Preferably, the temporary layer is optically inactive, that is to say that it allows the measurement of power with conventional measurement means such as the frontofocometer.

After application, the latex composition according to the invention is dried, generally by heating at temperatures typically varying from 40 ° C to 80 ° C, for a period of a few minutes to a few hours.

The advantageous results of the invention are obtained by simple drying and do not require actinic radiation.

The composition need not include a photoactivatable polymerization initiator.

Preferably, the latex composition is dried in a single step, by heating or maintaining at room temperature.

The following examples illustrate the present invention. In the examples, unless otherwise indicated, all parts and percentages are expressed by weight.

1. Latex compositions used in the examples

The latex compositions used in the examples are given in Table I below.

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The values ​​in brackets in Table I correspond to the amounts of the liquid components (liquid latex, surfactant, etc.) used.

The total dry extracts of the resulting compositions and of the starting materials are shown in the right column of Table I.

2. Preparation of latex compositions No. 7 and 8

The weighed quantity of PROX R 910® is placed in a beaker and the weighed quantities of PROX AM 185 RS®, ACTIRON F 487® and possibly MODAREZ PW 336® are added successively and the mixture is stirred with a RAYNERIE (deflocculating turbine diameter 35mm) starting at low speed then increasing the speed gradually up to 1800 rev / minute and stirring is continued for about 2 and a half hours.

It is left to stand overnight (elimination of microbubbles) before use.

3. Determination of surface energy characteristics of temporary layers of dried latex compositions

- Preparation of samples

The latex compositions are deposited by dip coating on a bare substrate, biplane, base 6, in copolymer of diethylene glycol bis allyl carbonate (CR 39® from the company PPG - ORMA® from the company ESSILOR) using a processing machine. dip coating with a dewetting speed of 1mm / s and a dwell time of 10 seconds. The coated samples are then dried in an oven at 50 ° C for 2 hours.

- Determination of surface energy characteristics

The characteristics of surface energy, total energy, dispersive component and polar component are determined by the method of OWENS

- WENDT using a DIGIDROP GBX device.

By way of comparison, the surface energy characteristics of two hydrophobic and / or oleophobic coatings, namely OPTOOL DSX® from the company DAIKIN and KY 130 from SHINETSU, are also given.

The results are given in Table II below.

TABLE II

<td rowspan="2">Nature of the layer</td><td rowspan="2">Thickness (pm)</td><td colspan="3">Surface energy (mJ / m²)</td>

<td>Total</td><td>Dispersive component</td><td>Polar component</td>

<td>1a</td><td></td><td> 39,7</td><td> 34,3</td><td> 5,4</td>

<td>1b</td><td></td><td> 37,6</td><td> 35,5</td><td> 2,1</td>

<td>1 C</td><td></td><td> 38,1</td><td> 34,8</td><td> 3,3</td>

<td>2a</td><td> 19</td><td> 43,6</td><td> 34,0</td><td> 9,5</td>

<td>2b</td><td></td><td> 44,2</td><td> 35,6</td><td> 8,6</td>

<td>2c</td><td></td><td> 43,6</td><td> 35,8</td><td> 7,8</td>

<td>2d</td><td></td><td> 39,0</td><td> 28,0</td><td> 10,9</td>

<td>3a</td><td></td><td> 43,4</td><td> 34,5</td><td> 8,9</td>

<td>3b</td><td></td><td> 39,8</td><td> 37,2</td><td> 2,6</td>

<td>3c</td><td></td><td> 37,5</td><td> 33,7</td><td> 3,8</td>

<td>3d</td><td></td><td> 36,4</td><td> 32,4</td><td> 4,0</td>

<td>4a</td><td></td><td> -</td><td> -</td><td> -</td>

<td>4b</td><td></td><td> -</td><td> -</td><td></td>

<td>4c</td><td></td><td> 41,3</td><td> 32,6</td><td> 8,7</td>

<td>4d</td><td></td><td> 47,1</td><td> 26,8</td><td> 20,3</td>

<td> 5</td><td></td><td> 36,8</td><td> 34,8</td><td> 2,0</td>

<td> 6</td><td></td><td> 40,9</td><td> 33,1</td><td> 7,8</td>

<td> 7</td><td></td><td> 40,5</td><td> 33,3</td><td> 7,2</td>

<td> 8</td><td> 19</td><td> 43,5</td><td> 31,6</td><td> 12,1</td>

<td>OPTOOLD SX</td><td>2.6nm</td><td> 11,3</td><td> 11,1</td><td> 0,2</td>

<td>KY130</td><td></td><td> 13,1</td><td> 13,0</td><td> 1,0</td>

Examples 1 to 10 and Comparative Examples C1 to C6.

As described above, temporary layers were formed on

<td> -</td><td>an ORMA® substrate (sphere: -5.00 cylinder + 2.00, diameter 65mm and thickness in the center 1.9mm) a polycarbonate substrate (sphere: -8.00 cylinder: +2.00 diameter 65mm and thickness in the center 1.3mm) an ORMIX® 1.6 substrate (sphere: -8.00 cylinder: +2.00 diameter 65mm and thickness in the center 1.1mm</td>

previously coated, in the order indicated, with an abrasion-resistant coating, an anti-reflection coating and a hydrophobic and / or oleophobic outer coating (OPTOOL DSX, thickness 2.6 nm) as described in Example 1 of patent EP 1 392 613. The formation of the temporary layer was observed visually and tests were carried out for overflow and piercing of the samples. The characteristics of the temporary layers and the results are given in Table III.

PROTOCOL FOR MEASURING DEAXING OF LENSES SUBJECT TO AN EDGE OPERATION

I- Description of the test

The edging test is carried out on an Essilor Kappa grinder.

The lenses are overhang so as to give them the shape of a specific frame jig (see below).

The following equipment is required to perform the test: Essilor CLE 60 frontofocometer (for aiming the lenses and final check)

Essilor Kappa digital chain (Centering / Blocker and Grinder)

Charmant type frame jig reference 8320, model 05, size 51 Pseudo control frame.

Adhesive patch or adhesive pad LEAP II 24 mm diameter GAM200 from the company 3M

Essilor tassel to accommodate the adhesive patch.

II- Sampling and assembly parameters.

The assembly dimensions used are as follows:

Height: Half boxing height is

PD (right and left) = 32 mm and Axis = 90 °

The trimming cycle used is a cycle adapted to the material (plastic cycle for low index, polycarbonate cycle for PC and cycle for Medium refractive index MHI substrate). The clamping pressure retained is the pressure corresponding to the fragile glass option of the grinder.

III- Controls

After edging, a check is carried out in order to determine whether the edging operation has been carried out satisfactorily.

The checks are carried out using the CLE 60 frontofocometer by pointing at the lenses placed in the pseudo-frame. The axes are marked during this phase.

If the lens, after the edging operation cannot be inserted into the pseudo-frame or if the lens can be inserted into the pseudo-frame, but has an offset of more than 2 °, the lens is non-compliant and does not did not pass the test. It is referenced - in the results table.

If the lens has an offset of less than 2 °, the lens passes the test and is referenced X in the results table.

DRILLING AFTER TIP

After the edging operation, the lens and glans / adhesive pad assembly, with the acorn / adhesive pad firmly adhering to the lens is placed in an Optodrill or Minima2 drilling machine and held by a blocker.

The lens is then pierced

- either manually with the Minima 2 drill fitted with a 2.2 mm diameter drill, with a rotation speed of 3500 revolutions / minute.

-or automatically with the Optidrill Evo drill fitted with a 2.2 mm diameter drill bit with a rotation speed of 12,000 revolutions / minute.

After drilling, the fixing system is unscrewed and the pierced lens and the glans / adhesive pad are recovered.

Then the glans is removed and the pierced lens recovered.

When the lens can be positioned in the piercing device and thereby successfully passes the piercing operation, it is denoted X in Table III. Otherwise, it is noted -.

For the lenses of Examples 1 to 8 and C1 to C6, the adhesive pad loses its adhesion after the edging operation and does not allow drilling.

For the lenses of Examples 9 and 10, the adhesive pad remains firmly held on the lens after the edging operation and makes it possible to position the lens in the piercing device and to perform a correct piercing.

TABLE III

<td rowspan="2">Ex n °</td><td colspan="2">Temporary layer</td><td rowspan="2">Film formation</td><td rowspan="2">Simple overflow</td><td rowspan="2">Total overflow</td><td rowspan="2">Drilling after total overflow</td>

<td>Latex composition</td><td>Thickness (pm)</td>

<td> 1</td><td>2a</td><td> 19</td><td>X</td><td>X</td><td></td><td></td>

<td> 2</td><td>2b</td><td></td><td>X</td><td>X</td><td></td><td></td>

<td> 3</td><td>2c</td><td></td><td>X</td><td>X</td><td></td><td></td>

<td> 4</td><td>2d</td><td></td><td>X</td><td>X</td><td></td><td></td>

<td> 5</td><td>3a</td><td></td><td>X</td><td>X</td><td></td><td></td>

<td> 6</td><td>3b</td><td></td><td>X</td><td>X</td><td>X</td><td></td>

<td> 7</td><td>3c</td><td></td><td>X</td><td>X</td><td>X</td><td></td>

<td> 8</td><td>3d</td><td></td><td>X</td><td>X</td><td>X</td><td></td>

<td> 9</td><td> 7</td><td></td><td>X</td><td>X</td><td>X</td><td>X</td>

<td> 10</td><td> 8</td><td> 19</td><td>X</td><td>X</td><td>X</td><td>X</td>

<td>C1</td><td>4a</td><td></td><td></td><td></td><td></td><td></td>

<td>C2</td><td>4b</td><td></td><td></td><td></td><td></td><td></td>

<td>C3</td><td>4c</td><td></td><td></td><td></td><td></td><td></td>

<td>C4</td><td>4d</td><td></td><td></td><td></td><td></td><td></td>

<td>C5</td><td> 5</td><td></td><td></td><td></td><td></td><td></td>

<td>C6</td><td> 6</td><td></td><td></td><td></td><td></td><td></td>

X = yes

- = no

The contact angle with water of the hydrophobic and / or oleophobic outer coating of the sample of Example 8 was also measured after removal of the temporary layer with reference to the value of this contact angle for the same coating. hydrophobic and / or oleophobic before deposition of the temporary layer. By way of comparison, the measurement of the contact angle with water was carried out for a commercial product Platinum® (substrate of refractive index 1.56) from the company HANDOK OPTEC.

The measurements were repeated after treatment with caustic soda of the hydrophobic and / or oleophobic coating.

The results are given in Table IV

TABLE IV

<td rowspan="2"></td><td rowspan="2">Nature of the hydrophobic and / or oleophobic coating / temporary layer removed</td><td colspan="2">Contact angle with water (°)</td>

<td>Without caustic soda treatment</td><td>After treatment with caustic soda</td>

<td>EX 11 (invention)</td><td>OPTOOL DSX 2.6 nm / latex n ° 8 (example 10)</td><td> 117°- 120°</td><td> 114°- 115°</td>

<td>Ref. 1</td><td>OPTOOL DSX - 3 nm</td><td> 117°- 120°</td><td> 113°</td>

<td>Ref. 2</td><td>KY 130</td><td> 110°</td><td> 109°</td>

<td>Comparison 1</td><td>Platinum Product '⁹</td><td> 111°</td><td> -</td>

The contact angle is measured using a KRÜSS reference DSA 10 goniometer by depositing 5 drops of deionized water (4μΙ per drop) on the cleaned and dry surface of the lens, one in the center and the four others within 20mm of it.

The treatment with caustic soda which aims to check the resistance of the hydrophobic and / or oleophobic coating consists of soaking the lens for 1 minute in a 0.1 N soda solution, then rinsing with water and alcohol isopropyl, dry, measure the contact angles, soak again for 29 minutes in 0.1 N sodium hydroxide solution, rinse and dry again and measure the contact angles. The value of the contact angle is the average of the results.

The glass is considered to have successfully passed the caustic soda treatment when the average contact angle values ​​without soda treatment and the contact angle after soda treatment are close to the target values ​​defined below:

<td rowspan="2">Nature of the hydrophobic and / or oleophobic coating / temporary layer removed</td><td colspan="2">Target values ​​"Contact angle" with water (°)</td>

<td>Without caustic soda treatment</td><td>After treatment with caustic soda</td>

<td>OPTOOL DSX- 3nm</td><td> 117°-120°</td><td> 113°-114°</td>

<td>KY 130 (20nm consigned)</td><td> 110°</td><td> 109°</td>

The temporary coating according to the invention has the advantages of being applicable by the liquid route, of making it possible to mark the glasses on the temporary layer, of preserving the low surface energy of the hydrophobic and / or oleophobic coating, in particular of better to preserve the contact angle with water after removal of the temporary coating and to be versatile, that is to say to be able to be deposited on different hydrophobic and / or oleophobic layers.