NZ619974B2 - Optical article comprising a surfactant-based temporary antifog coating with an improved durability - Google Patents

Abstract

Disclosed is an optical article comprising a substrate coated with a coating possessing silanol groups on its surface, an antifog precursor coating comprising polyoxyalkylene, and a antifog surfactant composition of formula (CF 2)y(CH2-CH20)x+1H, wherein wherein x is an integer ranging from 1 to 14 and Y is an integer lower than or equal to 10. Also disclosed is a method of imparting antifog properties to an optical article by applying the coatings and compositions defined above to at least one portion of said articles surface. The surfactant is applied to the surface as a liquid composition which temporality adsorbs to the optical articles surface and imparts antifog properties to said article. and Y is an integer lower than or equal to 10. Also disclosed is a method of imparting antifog properties to an optical article by applying the coatings and compositions defined above to at least one portion of said articles surface. The surfactant is applied to the surface as a liquid composition which temporality adsorbs to the optical articles surface and imparts antifog properties to said article.

Description

OPTICAL E SING A TANT-BASED ARY ANTIFOG COATING WITH AN IMPROVED DURABILITY The present invention relates to an optical article, preferably a spectacle lens, comprising an antifog coating sor coating, characterized in that the antifog coating precursor coating is coated with a composition, ably a liquid solution, containing at least one surfactant corresponding to formula F(CF2)y-(CH2—CH20)X+1H , wherein y is an integer lower than or equal to 10 and compounds of a (VIII), in which y= 6 account for at least 90%, preferably at least 95% and more preferably 100% by weight of compounds of formula (Vlll) present in the composition ; x is an r ranging from 1 to 14.

The present invention also relates to a method for imparting antifog properties to an optical article, preferably a lens for spectacles, comprising a step for depositing the composition onto the surface of the article, preferably the liquid solution, as hereabove.

The present invention also relates to antifogging tissues impregnated with said composition.

Very numerous supports, such as plastic materials and glass, suffer as a drawback from becoming covered with fog when their surface temperature ses below the dew point of ambient air. This is especially the case with the glass or organic glass that is used to make glazing for transportation vehicles or buildings, lenses, especially for spectacles, mirrors, and so on. The fogging that develops on these es leads to a decrease in transparency, due to the diffusion of light through water drops, which may cause a substantial discomfort.

To t any fog formation in very damp environments, that is to say the condensation of very little water droplets on a support, it has been suggested to apply hydrophilic coatings onto the outer surface of such support, with a low static contact angle with water, ably of less than 50°, more preferably of less than 25°. Such ent antifog coatings do act as sponges toward fog and enable the water droplets to adhere to the surface of the t by forming very thin film that gives an impression of transparency. These coatings are generally made of highly hydrophilic species such as sulfonates or polyurethanes.

Commercially available products comprise several micrometer-thick hydrophilic layers. 3O As a rule, when the thickness of the coatings is high (several microns), these coatings, as a consequence of water tion, do swell, soften and become mechanically less resistant.

As used herein, a permanent antifog g is intended to mean a coating which hydrophilic properties result from hydrophilic compounds permanently bound to another coating or support.

The application EP 1324078 describes a lens coated with an abrasion—resistant coating and ayered antireflective coating comprising layers with high and low refractive indexes ating with each other, amongst which the outer layer is a low refractive index layer (1.42- 1.48) of from 5 to 100 nm thickness forming an antifog coating consisting in a hybrid layer with a static contact angle with water of less than 10°, obtained through vacuum deposition of both simultaneously an organic compound and silica or of silica and alumina, that is to say through 40 coevaporation of these various components. The antifog coating preferably comprises from 0.02 to 70% by weight of the organic compound relative to the coating total weight, and typically from 6 to 15% by weight, ing to the examples.

Said organic nd comprises one hydrophilic group and one reactive group, for e a trialkoxysilyl group having from 3 to 15 carbon atoms, and has preferably a lar weight g from 150 to 1500 g/mol. Some preferred compounds possess a polyether backbone, especially one polyoxyethylene and one reactive group on each end of the molecule.

Preferred compounds include polyethylene glycol glycidyl ether, hylene glycol rylate and N—(3—trimethoxysilylpropyl)gluconamide.

The g coating therefore comes as a silica-based layer (or a silica + alumina-based layer) 1O incorporating one hydrophilic organic compound. However, its antifog ter does change over time, and it can be observed a stepwise deterioration of the antifogging properties. When becoming too low, they may be restored through a ”washing treatment" of the antifog film, ularly a plasma—mediated treatment. in the practice, the coevaporation method of the application EP 1324078 is very complicated to implement. It would be preferable to have a method for making an g coating t carrying out any coevaporation process.

The American patents US 6,251,523 and US 6,379,776 describe an antireflective, antifog glass for cars or lenses, comprising a glass substrate provided with an antireflective coating based on 110-250 nm-thick silica with a surface roughness Ra of about 5-10 nm, in turn provided with a 8 nm-thick permanent antifog coating obtained through liquid or vapor deposition of the compound CHgO-(CH20H20)5-9—(CH2)3Si(OCH3)3 or a hydrolyzate thereof. At the initial stage, the antifog coating has a static contact angle with water of 3°.

Another solution to combine antireflective and antifogging properties consists in using a thin porous low tive index layer, partially made of surfactants, which enable the layer to acquire antifogging properties. This layer is generally deposited onto a hilic surface.

Thus, the patent US 5,997,621 describes a porous antireflective and antifog coating based on metal oxides (silica beads) and relatively water-soluble anionic surfactants, having generally an ionic hydrophilic head of the carboxylic acid, sulfonate or ate type and a fluorinated chain.

In order to be immobilized on a substrate, the surfactants are preferably able to covalently bind to the metal oxides. The application WO 97/43668 describes a similar construction.

The ation EP 0871046 describes an antireflective and antifog system comprising one inorganic oxide—based porous layer deposited onto a few micrometer-thick water absorbing layer, obtained through polycondensation of an inorganic alkoxide hydrolyzate in the presence of a polyacrylic acid compound. The porous layer, which acts as the antireflective barrier, allows water to access the ing layer.

Antifogging properties may also be obtained by applying temporary ons commercially ble as sprays or towelettes, onto spectacle lenses comprising as the outer layer an antisoiling coating (hydrophobic and oleophobic), often considered as ial when ophthalmic lenses are provided with an antireflective coating. They make it possible to obtain the 40 antifogging property on a short period of time. The ease of soil removal aspect that is given to the antisoiling g is preserved, but after a couple of wiping operations, the antifogging property is significantly d. Indeed, temporary solutions comprise materials that are hydrophilic in nature with poor interactions with the iling coating hydrophobic surface, so that after a few wiping operations, these hydrophilic materials are removed.

A more interesting solution consists in making an antifog coating by applying a temporary hydrophilic solution onto the surface of an antifog coating precursor coating, which represents an alternative to permanent antifog gs.

The application EP 1275624 describes a lens coated with a hard, inorganic, hydrophilic layer based on metal oxides and silicon oxide. lts hydrophilic nature and the presence of nanosized concave portions on the surface thereof enable to impregnate a surfactant and to retain the same adsorbed over a long period of time, thus maintaining an antifog effect for several days. However, an antifog effect can also be observed in the absence of any surfactant.

The ations JP 2004—317539 and JP 2005—281143 describe a lens coated with a multilayered antireflective coating and/or with an abrasion—resistant coating and with an antifog coating precursor coating, having a static contact angle with water of from 50° to 90°. The antifog coating as such, which is a temporary coating, is obtained after application of a surfactant onto the surface of the precursor coating.

The antifog coating precursor coating is obtained from a composition comprising an c compound comprising a hilic group of polyoxyethylene nature, a reactive group e of reacting with the outer layer of the antireflective g, especially a silica-based layer, such as alkoxysilane Si(OR)n, silanol SiOH or isocyanate groups, and ally a fluorinated hydrophobic group, and the composition is chosen so that the static contact angle with water of the antifog coating precursor coating varies from 50° to 90°. The organic nds used in the antifog coating precursor ably have a molecular weight ranging from 700 to 5000 or from 430 to 3700 g/moi. To be mentioned as examples of such compounds are the CH30(CHZCHZO)ZZCONH(CH2)3Si(OCH3)3 or C8F170(CH2CHZO)ZCONH(CH2)38i(OCH3)3 compounds. The sor coating is described as being 0.5 to 20 nm thick. The vely high contact angle of the precursor coating is expected because it enables, according to these applications, to easily remove soils resulting from the drying of water drops. 3O The patent application describes a lens for spectacles comprising a substrate ed with a coating sing silanol groups on the surface thereof and, directly contacting this coating, an g coating precursor coating, wherein the antifog coating sor g: — is obtained through the grafting of at least one organosilane compound possessing: - a poiyoxyalkylene group comprising less than 80 carbon atoms, and - at least one silicon atom carrying at least one hydrolyzabie group, - has a thickness lower than or equal to 5 nm, - has a static contact angle with water of more than 10° and of less than 50°.

The solution which is preferably deposited to e this surface with antifogging properties is 40 the commercially available solution Defog itTM The antifogging properties, especially the durability of the gging effect associated with the lens precursor g bed in the patent application , are very satisfactory.

However, it is desirable to improve the antifogging mances of the lenses for spectacles, which are described in the patent ation . In particular, layers with more efficient antifogging properties are sought after, which would last longer over time and/or under mechanical stresses, while preserving an acceptable ease of soil removal.

Antifog coatings also having good mechanical ties (abrasion and scratch resistance) are still sought after. 1O The present invention aims at preparing such temporary antifog coatings, which significantly improve the antifogging property durability over time and/or under mechanical stresses.

It is a further objective of the present invention to e an antifog coating that would be immediately operational, that is to say a coating which, when a arent lens substrate coated with such coating is placed under conditions generating fog onto said substrate being devoid of said coating, enables to ately attain (that is to say in less than one second) a vision > 6/10 (visual acuity), and preferably of 10/10, without fog ion for an observer looking through a coated lens according to the Snellen E visual acuity scale (ARMAlGNAC scale (Tridents) (Snellen E) reading at 5 meters, ref. T6 ble from FAX lNTERNATlONAL), located at a distance of 5 meters.

It is a further objective of the present invention to e an l article having both antireflective and gging properties.

The foregoing objectives are to be read dlsjunctively with the objective of at least providing the public with a useful alternative.

These objectives may be aimed at, according to the invention, thanks to the application onto the optical article of a composition, preferably a liquid solution, containing at least one surfactant corresponding to a F(CF2)y—(CH2-CH20)X+1H (Vlll), wherein y is an integer lower than or equal to 10, compounds of formula (Vlll) in which y= 6 accounting for at least 90% by weight, preferably at least 95%, more ably 100% by weight of compounds of formula (Vlll) present in the composition, preferably a liquid solution, and x is an integer ranging from 1 to 14.

In particular, the present invention provides an optical article comprising a substrate having at least one main surface coated with a first coating and, directly contacting this first coating, a precursor coating of an antifog coating, wherein the coating precursor of the antifog coating: is obtained through the grafting of at least one organosilane compound : a polyoxyalkylene group, and at least one silicon atom bearing at least one hydrolyzable group; and is further coated with a film obtained by applying onto said precursor coating a surfactant- containing composition containing at least one surfactant of formula F(CF2)y—(CH2-CHZO)X+1H (Vlll), n x is an integer ranging from 1 to 14, y is an integer lower than or equal to 10, [FOLLOWED BY PAGE 4a] compounds of formula (Vlll) in which y=6 being present in an amount of at least 90% by weight relative to the weight of compounds (Vlll) t in the composition, so as to form an g coating.

In another embodiment, x in formula (VIII) is an integer from 2 to 14. The description is detailed hereafter in reference to the embodiment n x in formula (VIII) is an integer from 1 to 14 but the following description and all described and preferred features also apply to the embodiment wherein x, in formula (Vlll), is an integer from 2 to 14.

In the remainder of the specification, ments concerning a surfactant liquid solution will be described in more detail. 1O Preferably, the compounds of formula (Vlll), in which y is higher than 6, are present in an amount of less than 5% by weight, preferably less than 2% by weight, and more preferably 0%, relative to the weight of compounds (Vlll) present in the composition. ably, the liquid solution does not comprise surfactants other than those of formula Vlll.

In r embodiment, the surfactant-containing composition does not comprise any compounds of formula (Vlll), in which y=10.

[FOLLOWED BY PAGE 5] Preferably, the compounds of formula (VIlI), in which x ranges from 1 to 4, are present in an amount of at least 50% by weight, preferably at least 60% by , ve to the weight of compounds (Vlll) present in the ition.

Preferably, the compounds of formula (Vlll), in which x ranges from t to 5, are present in an amount of at least 70% by , preferably at least 80% by weight, relative to the weight of compounds (Vlll) present in the composition.

As is well-known from the person skilled in the art, the weights corresponding to each of the fractions d by the (x, y) s may be determined through HPLC, coupled to a mass spectrometry.

Thus, the t invention relates to an optical article, preferably a lens for spectacles, comprising a substrate provided with a first g and, directly contacting this first coating, an antifog coating precursor coating, characterized in that the antifog coating precursor coating: — is ed through the grafting of at least one organosilane compound possessing: o a polyoxyalkylene group, and 0 at least one silicon atom bearing at least one hydrolyzable group, - has ably a thickness lower than or equal to 5 nm, - has preferably a static contact angle with water of more than 10° and of less than 50°, and is further coated with a film obtained by applying the composition, preferably the surfactant liquid solution such as previously defined and forming an g coating, having preferably a static contact angle with water lower than or equal to 10°, more preferably lower than or equal to In the present application, a coating that is "on" a substrate/coating or which has been deposited "onto" a substrate/coating is defined as a coating that (i) is positioned above the substratefcoating, (ii) is not necessarily in contact with the substrate/coating, that is to say one or more intermediate coatings may be arranged between the substrate/coating and the coating in question (however, it is preferably in contact with said substrate/coating), and (iii) does not necessarily completely cover the substrate/coating. When "a layer 1 is arranged under a layer 2", it is intended to mean that layer 2 is more distant from the substrate than layer 1.

As used herein, an "antifog coating" is ed to mean a coating which, when a transparent lens substrate coated with such coating is placed under conditions generating fog onto said ate being devoid of said coating, enables to immediately attain a visual acuity > 6/10 for an observer looking through a coated lens at a visual acuity scale located at a distance of 5 meters. Several tests to evaluate the antifogging properties of a coating are described in the experimental section. Under fog generating conditions, antifog coatings may either not present fog on their surface (ideally no visual distortion, or visual distortion but visual acuity > 63/10 under the ove mentioned measurement conditions), or may present some fog on their surface but yet enable, e the vision perturbation resulting from fog, a visual acuity > 6/10 under the hereabove mentioned measurement conditions. A non-antifog coating does not allow a visual acuity > 6!10 as long as it is exposed to ions ting fog and generally presents a 40 condensation haze under the hereabove mentioned measurement conditions.

As used herein, an "antifog optical article" is intended to mean an optical article provided with "antifog coating" such as defined hereabove.

Thus, the antifog coating precursor according to the invention, which is a hydrophilic coating, is not considered as being an antifog coating according to the present invention, even if it has some antifogging properties, which may be observed for e by means of a breath test described in the experimental section. lndeed, this antifog coating precursor does not allow to obtain a visual acuity > 6/10 under the hereabove mentioned measurement conditions.

As used , a temporary antifog coating is intended to mean an antifog coating obtained after having applied the liquid solution containing the surfactant of formula (Vlll) onto the surface of the precursor coating of said antifog coating. The durability of a ary antifog coating is generally limited by the wiping operations med on the surface thereof, the surfactant molecules being not permanently attached to the surface of the coating but just adsorbed for more or less durable period of time.

The optical article prepared according to the invention comprises a substrate, preferably transparent, having front and rear main surfaces, at least one of said main es being provided with a coating preferably comprising silanol groups on the surface thereof, ably on both main surfaces. As used , the rear face (generally concave) of the substrate is intended to mean the face which, when using the article, is the nearest from the wearer’s eye. On the ry, the front face ally convex) of the ate, is the face which, when using the article, is the most distant from the wearer’s eye.

Although the e according to the invention may be any optical article that may encounter a problem of fog formation, such as a screen, a glazing for the automotive industry the building industry, or a , it is ably an optical lens, more preferably an ophthalmic lens, for spectacles, or a blank for optical or ophthalmic lenses.

This excludes articles such as intraocular lenses which are in contact with living tissues or contact lenses, which do not sically face the problem of fog formation, as d to lenses for spectacles.

According to the ion, the coating comprising silanol groups on its surface may be formed on at least one of the main surfaces of a bare substrate, that is to say a non coated substrate, or on at least one of the main surfaces of a substrate that has already been coated with one or more functional coatings.

The substrate for the optical article according to the invention may be a mineral or an organic glass, for e of a thermoplastic or thermosetting plastic material.

Especially preferred classes of substrates include poly(thiourethanes), polyepisulfides and resins resulting from the polymerization or (co)polymerization of alkyleneglycol bis allyl carbonates. These are sold, for example, under the trade name CR-39® by the PPG Industries company (ORMA® , from ESSlLOR).

In some applications, it is red that the substrate’s main surface be coated with one or more functional coatings prior to depositing the g comprising silanol groups on its 40 surface. These functional coatings traditionally used in optics may be, without limitation, an -resistant primer layer, an abrasion—resistant and/or a scratch—resistant g, a polarized coating, a photochromic coating or a tinted coating, particularly an impact-resistant primer layer coated with an abrasion-resistant and/or a scratch-resistant layer.

The coating comprising silanol groups on the surface thereof is preferably deposited onto an abrasion-resistant and/or a scratch-resistant coating. The abrasion-resistant coating and/or the scratch-resistant coating may be any layer traditionally used as an abrasion-resistant g and/or scratch-resistant coating in the ophthalmic lenses field.

The abrasion—resistant and/0r scratch-resistant coatings are preferably hard coatings based on poly(meth)acrylates or silanes comprising generally one or more mineral fillers that are 1O intended to improve the hardness and/or the refractive index of the coating once cured. As used herein, a (meth)acrylate is an acrylate or a methacrylate.

The abrasion—resistant coating and/or scratch—resistant hard coatings are preferably made from compositions comprising at least one alkoxysilane and/or a hydrolyzate thereof, obtained for example through hydrolysis with a hydrochloric acid solution, and optionally condensation and/or curing catalysts and/or tants.

Recommended coatings of the present invention include coatings based on epoxysilane hydrolyzates such as those described in the patents EP 0614957, US 4,211,823 and US ,015,523.

The thickness of the abrasion—resistant coating and/or scratch-resistant coating does generally vary from 2 to 10 um, preferably from 3 to 5 um.

Prior to depositing the abrasion-resistant g and/or the scratch-resistant coating, it is possible to apply onto the substrate a primer coating to improve the impact ance and/or the adhesion of the uent layers in the final product.

This coating may be any impact-resistant primer layer traditionally used for articles in a transparent polymer al, such as ophthalmic lenses.

Preferred primer compositions may be chosen from those described in , which is hereby incorporated by reference.

Preferred primer compositions are compositions based on polyurethanes and compositions based on latexes, particularly polyurethane type s and poly(meth)acrylic latexes, and their combinations. Primer layers generally have thicknesses, after curing, ranging from 0.2 to 2.5 pm, preferably ranging from 0.5 to 1.5 um.

The coating comprising silanol groups on the surface thereof will be described hereafter.

As used herein, a coating comprising silanol groups on the surface thereof is intended to mean a coating which naturally ses silanol groups on the surface thereof or a coating which silanol groups have been created after having been submitted to a surface activation treatment. This coating is ore a coating based on siloxanes or silica, for example, without limitation, a silica- based layer, a l g, based on organosilane species such as alkoxysilanes, or a coating based on silica colloids. The first coating, ably sing silanol groups at its surface, may be especially an abrasion—resistant and/or scratch-resistant coating, or, according 40 to the red embodiment, a yered antireflective g or a multilayered antireflective coating which outer layer has silanol groups on the surface thereof. As used herein, the outer layer of a coating is intended to mean the layer that is the most distant from the substrate.

The surface activating treatment generating the silanol groups or at least increasing their proportion on the surface of a g is generally performed under . It may be a dment with energetic and/or reactive species, for example with an ion beam (“lon Pre— Cleaning” or “IPC”) or with an on beam, a corona rge treatment, an ion spallation treatment, an ultraviolet treatment or a -mediated treatment under vacuum, generally using an oxygen or an argon plasma. It may also be an acidic or basic ent and/or a solvent—based treatment (water, hydrogen peroxide or any organic t). Many of these treatments may be combined.

As used herein, energetic species (and/or reactive species) are intended to mean especially ionic species with an energy ranging from 1 to 300 eV, preferably from 1 to 150 eV, more preferably from 10 to 150 eV, and even more preferably from 40 to 150 eV. The energetic species may be chemical species such as ions, radicals or species such as photons or electrons.

The activating treatment may also be an acidic or a basic chemical e treatment, preferably a wet treatment or a treatment using a solvent or a combination of solvents.

The coating comprising silanol groups on the surface f is preferably a low refractive index layer based on silica (comprising silica), most preferably it consists in a silica—based layer (Slog), generally ed through vapor phase deposition.

Said layer based on Si02 may comprise, in addition to silica, one or more other materials traditionally used for making thin layers, for example one or more materials selected from dielectric materials described hereafter in the present specification. This layer based on Si02 is preferably free of Al203.

The inventors observed that it is not essential to carry out a surface treatment when the layer is a layer based on silica, particularly when obtained through evaporation.

The coating comprising silanol groups on the surface thereof preferably comprises at least 70% by weight of SiOz, more preferably at least 80% by weight and even more preferably at least 90% by weight of SiOg. As has already been noticed, in a most preferred embodiment, it comprises 100% by weight of silica.

The g sing silanol groups on the surface thereof may also be a l coating based on silanes such as alkoxysilanes, for example tetraethoxysilane or organosilanes such as y—glycidoxypropyl trimethoxysilane. Such a g is obtained through wet deposition, by using a liquid composition comprising a hydrolyzate of silanes and optionally colloidal materials with a high (> 1.55, preferably > 1.60, more preferably > to 1.70) or a low (5 1.55) tive index. Such a coating which layers comprise an organic/inorganic hybrid matrix based on silanes wherein colloidal materials are dispersed to adjust the tive index of each layer are described for example in the patent FR 2858420. in one embodiment of the invention, the coating comprising silanol groups on the surface thereof is a layer based on silica deposited onto an on-resistant coating, preferably 40 deposited directly onto this abrasion-resistant coating.

Said layer based on silica (comprising ) is preferably a silica-based layer, generally obtained through chemical vapor deposition. It has preferably a thickness lower than or equal to 500 nm, more ably ranging from 5 to 20 nm, and even more preferably from 10 to 20 nm.

Preferably, the deposition of said layer based on silica is carried out by regulating the pressure, which means by adding gas to the tion chamber, the gas being in a non ionic form, preferably by adding oxygen, at a pressure ranging typically from 5.10"5 to 510'4 mbar. in another embodiment of the invention, which is the most preferred ment, the optical e according to the invention comprises an antireflective coating. When such a coating is present, it lly represents the coating comprising l groups on the surface thereof 1O within the meaning of the invention. This antireflective coating may be any antireflective coating traditionally used in the optics field, particularly ophthalmic optics, provided it comprises silanol groups on its surface.

An antireflective coating is defined as a g, deposited onto the surface of an optical article, which improves the antireflective properties of the final optical article. It makes it le to reduce the light reflection at the article-air interface over a relatively large portion of the visible spectrum.

As is also well known, antireflective coatings traditionally comprise a monolayered or a ayered stack composed of tric materials. These are preferably multilayered coatings, comprising layers with a high refractive index (Hl) and layers with a low refractive index (Ll).

In the present application, a layer of the antireflective coating is said to be a layer with a high refractive index when its refractive index is higher than 1.55, preferably higher than or equal to 1.6, more preferably higher than or equal to 1.8 and even more preferably higher than or equal to 2.0. A layer of an antireflective coating is said to be a low refractive index layer when its refractive index is lower than or equal to 1.55, preferably lower than or equal to 1.50, more preferably lower than or equal to 1.45. Unless otherwise specified, the refractive indexes referred to in the present invention are expressed at 25 °C at a wavelength of 550 nm.

The HI and Ll layers are traditional layers well known in the art, generally comprising or more metal oxides, which may be chosen, without limitation, from the materials disclosed in When a Ll layer comprising a mixture of SiOz and Aleg is used, it preferably comprises from 1 to 10%, more preferably from 1 to 8% and even more preferably from 1 to 5% by weight of Al203 ve to Si02 + Al203 total weight in this layer.

Typically, Hl layers have a al thickness ranging from 10 to 120 nm, and Ll layers have a physical thickness ranging from 10 to 100 nm.

Preferably, the antireflective total thickness is lower than 1 micron, more preferably lower than or equal to 800 nm and even more preferably lower than or equal to 500 nm. The antireflective total thickness is generally higher than 100 nm, preferably higher than 150 nm.

Still more preferably, the antireflective g comprises at least two layers with a low refractive index (Ll) and at least two layers with a high refractive index (Hl). Preferably, the total number of layers in the antireflective coating is lower than or equal to 8, more preferably lower than or equal to 6.

HI and LI layers do not need to alternate with each other in the antireflective coating, although they also may, ing to one embodiment of the invention. Two HI layers (or more) may be deposited onto each other, as well as two Ll layers (or more) may be deposited onto each other.

The various layers of the antireflective coating may be deposited according to any one of the methods disclosed in WO 80472, which is hereby incorporated by reference. A particularly recommended method is ation under vacuum. 1O When the coating comprising silanol groups on the surface thereof is an antireflective coating, the luminous reflection factor of an article coated with such an antireflective coating, noted RV, is preferably of less than 2.5% per face of the article. The means to reach such Rv values are well known from the person skilled in the art. in the present application, the "luminous reflection factor" is such as defined in the ISO standard 1366621998, and is measured according to lSO 8980—4 standard, that is to say it is the weighted average of the spectral reflectivity within all the visible spectrum wavelength range from 380 to 780 nm.

Prior to forming the antifog coating sor on the coating comprising silanol groups on the surface thereof, for example an antireflective coating, it is usual to submit the e of such coating to a physical or chemical activation treatment intended to reinforce the adhesion of the antifog coating precursor. These treatments may be selected from those previously bed for activating the coating comprising silanol groups on its surface.

According to the invention, the coating comprising l groups on the surface thereof is directly in contact with the precursor coating of an antifog coating, which will be bed hereunder.

As used herein, "a precursor of an antifog coating" is intended to mean a coating which, if a surfactant-containing liquid on is applied on the surface thereof so as to form a film, represents an antifog g within the meaning of the invention. The system precursor coating + surfactant-based solution film represents the antifog coating as such.

The antifog coating precursor coating is a coating having a thickness preferably lower than or equal to 5 nm, preferably of 4 nm or less, more preferably of 3 nm or less and even more ably of 2 nm or less, possessing preferably a static contact angle with water of more than ° and of less than 50°, which is ed through a permanent grafting of at least one organosilane compound possessing a polyoxyalkylene group and at least one silicon atom g at least one hydrolyzable group.

In one embodiment of the invention, the coating is deposited by applying a composition comprising a hydrolyzate of the organosilane compound possessing a polyoxyalkylene group and at least one silicon atom carrying at least one yzable group.

It is recommended to avoid any condensation of the hydrolyzed organosilane nds so that they can keep as much as le the silanol functions free to react so as to facilitate the 40 grafting of these compounds onto the surface of the optical e and to limit the formation of WO 13929 siloxane prepolymers before grafting. That is the reason why the deposited silane compound thickness is so thin. it is therefore recommended to apply the composition relatively y after the hydrolysis, lly within less than 2 hours, preferably less than 1 hour, more ably less than 30 minutes after having performed the hydrolysis (by adding a lly HCl—based, acidic aqueous solution).

Most ably, the ition is applied less than 10 minutes, even more preferably less than 5 minutes and preferably less than 1 minute after having performed the hydrolysis. it is preferred to t the hydrolysis without supplying heat, i.e. typically at a temperature of from 20 to 25 °C.

As a rule, the deposition of few nanometer-thick layers requires to use very diluted compositions, with a very low dry matter content, which slows down the condensation kinetics.

The organosilane compound used is capable, thanks to its silicon—containing reactive group, to establish a covalent bond with the silanol groups present onto the surface of the coating onto which it is deposited.

The organosilane compound of the invention comprises a polyoxyalkylene chain functionalized at only one end or at both ends thereof, preferably at only one end, by a group sing at least one silicon atom carrying at least one hydrolyzable group. This organosilane compound comprises preferably a silicon atom carrying at least two hydrolyzable groups, preferably three hydrolyzable groups. Preferably, it does not comprise any urethane group. it is ably a compound of formula: R1YmSi(X)3-m (I) wherein the Y groups, being the same or different, are monovalent organic groups bound to the silicon atom through a carbon atom, the groups X, being the same or different, are hydrolyzable groups, R1 is a group comprising a polyoxyalkylene function, m is an integer equal to 0, 1 or 2.

Preferably m = 0.

The X groups are ably selected from alkoxy groups ~O-R3, particularly C1-C4 alkoxy groups, acyloxy groups -O-C(O)R“ where R4 is an alkyl radical, preferably a 01-06 alkyl radical, preferably a methyl or an ethyl, halogens such as Cl, Br and l or trimethylsilyloxy (CH3)3SiO-, and combinations of these groups. Preferably, the groups X are alkoxy groups, and particularly methoxy or ethoxy groups, and more preferably ethoxy groups.

The Y group, present when m is not zero, is preferably a saturated or unsaturated hydrocarbon group, preferably a 01-010 and more preferably a C1—C4 group, for example an alkyl group, such as a methyl or an ethyl group, a vinyl group, an aryl group, for example an optionally substituted phenyl group, especially substituted by one or more C1—C4 alkyl groups. ably Y represents a methyl group.

In a preferred embodiment, the compound of formula! comprises a trialkoxysilyl group such as a triethoxysilyl or a trimethoxysilyl group.

The polyoxyalkylene group of the organosilane compound (group R1) comprises 40 preferably less than 80 carbon atoms, more preferably less than 60 carbon atoms, and even 2012/062620 more preferably less than 50 carbon atoms. Most preferably, the polyoxyalkylene group comprises less than 40 carbon atoms and more preferably less than 30 carbon atoms. The most preferred compounds have a polyoxyalkylene group which comprise from 5 to 20 carbon atoms.

The group R1 preferably satisfies the same conditions.

The R1 group corresponds generally to the formula ~L~R2‘ where L is a nt group bound to the silicon atom of the compounds of formula I or II h a carbon atom, and R2 is a group comprising one polyoxyalkylene group bound to the group L through an oxygen atom, this oxygen atom being included in the group R2. Non limiting examples of L groups include linear or branched, optionally substituted alkyl, cycloalkylene, arylene, yl, amido groups, or 1O combinations of these groups like cycloalkylenealkylene, biscycloalkylene, biscycloalkylenealkylene, arylenealkylene, bisphenylene, bisphenylenealkylene, amido alkylene groups, amongst which for example the group H2)3, or H(OH)CH2~ and — NHC(O)- groups. Preferred L groups are alkyl groups (preferably linear), having preferably 10 carbon atoms or less, more preferably 5 carbon atoms or less, for example ethylene and ene groups.

Preferred R2 groups comprise a polyoxyethylene group —(CH2CH20)n—, a ypropylene group, or combinations of these groups.

The preferred organosilanes of formula l are compounds of following formula II: Ym(X)3-mSi(CH2)n'—(L')m~—(OR)n—O—(L")m-_R' (II) where R' is a hydrogen atom, a linear or branched acyl or alkyl group, optionally substituted by one or more functional groups, and which may furthermore comprise one or more double bonds, R is a linear or branched alkyl group, preferably linear, for example an ne or a propylene group, L' and L" are divalent groups, X, Y and m are such as defined hereabove, n’ is an integer ranging from 1 to 10, preferably from 1 to 5, n is an integer g from 2 to 50, preferably from 5 to 30, more preferably from 5 to 15, m' is O or 1, ably 0, m" is O or 1, preferably 0.

The groups L' and L", when present, may be selected from divalent groups L previously described and represent preferably the group -OCH2CH(OH)CH2- or the group ~NHC(O)—. in this case, the groups —OCHQCH(OH)CH2- or -NHC(O)- are linked to the adjacent groups (CH2),,» (with a group L') and R' (with a group L") h their oxygen atom (for the group -OCHZCH(OH)CH2-) or through their nitrogen atom (for the group —NHC(O)—).

In one embodiment, m = 0 and the hydrolyzable groups X represent methoxy or ethoxy groups. n' is preferably 3. In another ment, R' represents an alkyl group possessing less than 5 carbon atoms, preferably a methyl group. R' may also ent an aliphatic or aromatic acyl group, especially an acetyl group.

Lastly, R' may represent a oxysilylalkylene group or a trihalogenosilylalkylene group such as a group -(CH2)n-'Si(R5)3 where R5 is a hydrolyzable group such as the previously defined X groups and n" is an integer such as the previously defined n' integer. An example of such a R’ group is the group —(CH2)3Si(OCZH5)3. In this embodiment, the organosilane compound comprises two silicon atoms carrying at least one hydrolyzable group. in preferred embodiments, n is 3, or does range from 6 to 9, from 9 to 12, from 21 to 24, or from 25 to 30, preferably from 6 to 9.

To be mentioned as suitable nds of formula II are for example 2- [methoxy(polyethyleneoxy)propyl]trlmethoxysilane compounds of formulas CHao-(CHZCHZO)3.9- Si(OCH3)3 (Ill) and CH20H20)9_12-(CH2)3Si(OCH3)3 (IV), marketed by Gelest, lnc. or ABCR, the compound of formula CHao-(CHQCH20)3-(CH2)38i(OCH3)3 (Vllla), compounds of formula CHSO-(CHZCH20)n-(CH2)38i(OCQH5)3 where n: 21-24, 2- xy(polyethyleneoxy)propyl] trichlorosilanes, 2~[acetoxy(polyethyleneoxy)propyl] trimethoxysilane of formula CH30(O)O‘(CHQCH20)6.9'(CH2)3Si(OCH3)3; 2— [acetoxy(polyethyleneoxy)propyl] triethoxysilane of formula CH30(O)O-(CHZCHZO)5.9- (CH2)38i(OCZH5)3, 2—[hydroxy(polyethyleneoxy)propyl]trimethoxysilane of formula HO- (CHQCH20)6.9-(CH2)3Si(OCH3)3, 2-{hydroxy(polyethyleneoxy)propyl]triethoxysilane of a HO- (CHZCH20)6.9-(CH2)38i(002H5)3, compounds of formulas HO-(CHgCH20)3_12-(CH2)3Si(OCH3)3 and HO-(CH20H20)8(CH2)3Si(002H5)3, polypropylene-bis[(8‘methyldimethoxysilyl)propyl] oxide, and compounds with two siloxane heads such as polyethylene-bis[(3-triethoxysilylpropoxy)-2« hydroxypropoxy] oxide of formula (V), polyethylene-bis[(N,N'-triethoxysilylpropyl)—aminocarbonyl] oxide of formula (Vi) with n = 10-15 and polyethylene—bis(triethoxysilylpropyl) oxide of formula (Vll): OH OH I | (CEHSO)BSi(CH2)3OCHZCHCHZO(CHZCHEO)54OCHZCHCH20(CH2)3Si(OCZH5)3 (V) o 0 ll ll (02H50)38i(CH2)3NHCO(CHQCHQO)nCONH(CH2)3Si(OCQH5)3 (Vl) (CZHSO)3Si(CH2)SO(CHZCH20)25.3O(CH2)38i(OCBH5)3 (W) Preferred nds of formulall are [alkoxy(polyalkylenoxy)alkyl]trialkoxysilanes or their trihalogenated analogues (m = m' = m" = O, R' = alkoxy).

Preferably, the organosilane compound of the invention has no fluorine atom. Typically, the fluorine weight ratio towards the antifog coating precursor coating is of less than 5%, ably of less than 1% by weight and more preferably of 0%.

SUBSTITUTE SHEET (RULE 26) Preferably, the molecular weight of the organosilane compound according to the invention ranges from 400 to 4000 g/mol, preferably from 400 to 1500 g/mol, more preferably from 400 to 1200 g/mol, and even more preferably from 400 to 1000 g/mol.

Of course it is possible to graft a mixture of compounds of formula l or II, for example a mixture of compounds with different polyoxyalkylene RO chain lengths. in one embodiment of the invention, the antifog coating precursor comprises more than 80% by weight of an organosilane compound according to the invention, relative to the antifog coating precursor total weight, preferably more than 90%, more preferably more than 95% and most ably more than 98%. in one embodiment, the antifog coating precursor consists in a 1O layer of said organosilane compound.

Preferably, the antifog coating precursor of the invention comprises less than 5% by weight of a metal oxide or metalloid (for example silica or alumina) relative to the coating total , more ably it is free of any. When the organosilane compound used for making the antifog coating is deposited under vacuum, preferably no metal oxide is co—evaporated, ing to the coevaporation method of at least one organic compound and at least one inorganic compound described in the ation EP 1324078.

Preferably, the antifog coating sor coating does not se any crosslinking agent, which means that is is preferably not formed from a composition comprising a inking agent, for example tetraethoxysilane.

The antifog coating precursor of the invention has preferably a static contact angle with water of more than 10° and of less than 50°, preferably lower than or equal to 45°, more preferably S 40°, even more preferably S 30° and most preferably 5 25°. This t angle does preferably range from 15° to 40°, more preferably from 20° to 30°.

The deposition of the organosilane compound onto the surface of the coating comprising l groups may be carried out according to usual procedures, preferably by gas phase deposition or liquid phase deposition, most preferably in the gas phase, by vacuum evaporation.

When the grafting is carried out in the gas phase, for example by evaporation under vacuum, it may be followed, if needed, with a step for removing the excess of the deposited organosilane compound so as to retain only the silane compound that is really grafted onto the surface of the l group~containing coating. Non grafted molecules are thus removed. Such a removal step should be preferably performed when the ess of the antifog coating precursor initially deposited is higher than 5 nm. r this step for ng the organosilane compound in excess can be omitted in some cases, seeing that it is possible to deposit the organosilane compound so as to form a grafted layer, that is to say once it is d that the deposited thickness does not exceed a few nanometers. Adjusting the deposition parameters for obtaining such thicknesses belongs to the ry competence of any person skilled in the art.

Nevertheless, it is preferred to form the antifog coating precursor coating by depositing some organosilane compound in excess onto the surface of the coating comprising silanol 40 groups and thereafter removing the excess of this deposited but not grafted compound. Indeed, the inventors observed that when a layer of grafted silane compound is directly formed with a thickness lower than or equal to 5 nm, which does not require any removal of organosilane compound in excess, it is sometimes possible to obtain a precursor coating of an antifog coating, the surface of which has not a sufficient y towards a liquid solution sing at least one surfactant, which would lead to a coating not having the desired antifogging properties.

Surprisingly, this is not observed when the organosilane nd is deposited in excess, as previously indicated, and such excess is removed later on. The actual physical thickness of the organosilane compound layer ted in excess is preferably lower than or equal to 20 nm. 1O Removing the organosilane compound deposited in excess may be performed by rinsing (wet process) using for e a soapy water—based solution and/or by wiping (dry process).

Preferably, the removal step comprises a rinsing operation followed with a wiping operation.

Preferably, the rinsing operation is performed by cleaning the article with some soapy water (comprising a tant) using a sponge. Thereafter a g ion is med with deionized water, and optionally, the lens is thereafter submitted to a wiping operation for typically less than 20 seconds, preferably 5 to 20 seconds, by means of a CElVlOlTM or SelvithiM cloth impregnated with alcohol, typically pyl alcohol. Another rinsing ion with deionized water may then be repeated, then a wiping operation with a wiping cloth. All these steps may be carried out manually or be lly or fully automated.

The step of removing the organosilane compound in excess leads to an organosilane nd layer having generally and preferably a thickness of 5 nm or less. In this case, the organosilane compound deposited onto the surface of the optical article forms a monomolecular or a quasi—monomolecular layer.

The organosilane compound may be beforehand dissolved in a solvent prior to being ated, for better controlling the evaporation rate and the deposition rate. The thickness of the film may be controlled in this way thanks to this dissolution and by adjusting the amount of solution to be evaporated.

When the grafting is carried out using a wet process, for example by dipping or spin- coating, it is lly not necessary to perform a step for removing the organosilane compound deposited in .

The antifog coating precursor coating according to the invention has a low roughness.

Typically, for an organosilane compound deposited by vapor phase, the roughness mean value Ra is lower than 2 nm, typically of about 1nm. Ra is such as defined in WC 20111080472.

A temporary antifog coating according to the invention is obtained by depositing onto the antifog coating precursor coating a film of a ition, preferably a liquid solution, comprising at least one surfactant of formula F(CF2)y-(CH2-CH20)X+1H (Vlll), wherein y is an integer lower than or equal to 10, compounds of formula (Vlll), n y: 6, accounting for at least 90% by weight, preferably at least 95%, more preferably 100% by weight of compounds of formula (Vlll) present in the composition, X is an integer ranging from 1 to 14, and in another embodiment from 40 2 to 14.

This solution provides the optical article, ably a lens for spectacles with an antifog temporary protection by creating on their surface a m layer that contributes to disperse the water droplets on the surface of the optical article so that they do not form any visible fog.

Applying the surfactant on may be performed by any known , especially by dipping or spin-coating.

The surfactant on is preferably applied by depositing a drop of this on onto the surface of the antifog coating precursor and then by spreading it so as to cover preferably the whole precursor coating.

The surfactant solution applied is generally an aqueous solution, comprising preferably from 0.5 to 15%, more preferably from 2 to 8% by weight of tants having a Vlll, relative to the weight of the liquid solution. The solution may also comprise alcohols, such as ethanol or isopropyl alcohol, in an amount generally of less than 10% by weight.

The surfactant composition based on compounds of formula (Vlll) being singly significantly more efficient to provide long-lasting antifogging properties, it may be employed in reduced s as compared to surfactants of the prior art, typically in amounts ranging from 2 to 5% by weight, more preferably from 2 to 4% by weight, relative to the weight of the composition.

In more preferred embodiments, a tissue or cloth is impregnated by the inventive surfactant-containing composition based on compounds of formula (VIII) and the tissue is directly used to confer antifogging ties to the optical article coated with the precursor coating by wiping it with said cloth.

There is then no need to previously deposit a drop of the surfactant solution of compounds of formula (VIII).

It has been found that a non woven tissue whose structure ses a hydrophilic polymer and a hydrophobic polymer impregnated by the surfactant compositions based on compounds of formula (Vlll) provides or results in terms of transparency and durability.

An exemple of such a tissue is the tissue “wetlaid” manufactured by the Ahlstrom company.

Indeed, t wishing to be d by a theory, the inventors think that the hydrophilic polymer on one side absorbs the surfactant composition and is able to make a reservoir effect and the hydrophobic polymer on the other side releases the tant composition.

A preferred hydrophilic polymer is a polymer comprising cellulosic units.

It is also preferred to use a surfactant aqueous composition as described previously comprising a monofunctional alcohol and a difunctional alcohol, said monofuctional alcohol having preferably a lower molecular weight than said difunctional alcohol.

The monofunctional alcohol comprises one single hydroxy group, lly ethanol or isopropyl alcohol. The difunctional alcohol comprises only two hydroxy groups. An example of a particularly red difunctional alcohol is propylene glycol (propane-1, 2-diol).

The ion also relates to a non woven wet tissue whose structure comprises a 40 hydrophilic polymer. preferably a hydrophilic polymer comprising cellulosic units, and a hydrophobic polymer, said tissue being impregnated by a surfactant-containing composition based on compounds of formula (Vlll) such as bed ove. in another preferred embodiment, the application of the surfactant containing composition onto said precursor coating is made by wiping the optical article coated with said precursor coating with a dry microfiber tissue, said dry microfiber tissue having been obtained by impregnation, with a surfactant containing composition based on compounds of formula (Vlll) such as described hereabove, of a microfiber tissue comprising microfibers made of polymers comprising ter units and polyamide units, followed by a drying step.

The microfiber tissue used in the invention preferably comprises ibers of polyester 1O and microfibers of polyamide and/or microfibers comprising a ter/polyamide copolymer.

As known in the art, a microfiber tissue or cloth is made of microfibers. A microfiber is a fiber with less than 1.3 Decitex (Dtex) per filament, ably less than 1 Decitex per filament.

Decitex is a measure of linear density and is commonly used to describe the size of a fiber or filament. Ten thousand meters of a 1-decitex fiber weighs one gram. In a microfiber tissue, fibers are combined to create yarns, which are knitted or woven in a variety of constructions.

An example of a preferred microfiber tissue comprising microfibers made of polymers sing polyester units and polyamide units is the M tissue (manufacturer: KB SEIREN Company — retailer: Facol) whose composition is polyester 70% I NylonTM 30% and that is commonly used for cleaning lenses. The microfiber tissue described above is generally impregnated by the surfactant containing composition using impregnation pad(s).

The purpose of the drying step in the preparation of the dry microfiber tissue is to remove ts present in the surfactant containing composition. it is generally a heating step. The heating step preferably comprises heating at a temperature ranging from 60°C to 200°C, more preferably from 80°C to 150°C.

After the heating step, the iber tissue comprising microfibers made of polymers sing polyester units and polyamide units is dry and the weight content of surfactants of formula (Vlll) impregnating said microfiber tissue preferably ranges from 10% to 45%, more preferably 14% to 40 %, even better from 20 to 40% and optimally from 20% to 30% relative to the total weight of the dry impregnated microfiber tissue (tissue and surfactant). In addition, compounds of formula (Vlll) in which y=6 are present in an amount of at least 90% by weight, preferably at least 95%, more preferably 100% by weight, relative to the weight of compounds (Vlll) in the impregnated microfiber tissue.

It has been determined that, surprisingly, the dry microfiber tissue comprising microfibers made of polymers comprising polyester units and polyamide units having been impregnated by the surfactant containing composition based on surfactants of formula (VIII) is still able to remove smudges from the surface of optical articles, while ing at the same time antifogging properties with long lasting effect.

The invention also relates to a dry iber tissue which has been ed by impregnation, with a surfactant containing composition based on compounds of formula (Vlll), of 40 a microfiber tissue sing microfibers made of polymers sing polyester units and polyamide units, followed by a drying step. Said dry microfiber tissue comprising microfibers made of polymers having polyester and polyamide units is thus impregnated with at least one surfactant of formula (VIII), where compounds of formula (VIII) in which y=6 are present in an amount of at least 90% by weight, preferably at least 95%, more preferably 100% by weight, relative to the weight of compounds (VIII) impregnated in the microfiber tissue.

The surfactant solution reduces the static contact angle with water of the surface of the optical article, especially of a spectacle lens. The antifog coating of the ion preferably has a static contact angle with water lower than or equal to 10°, more ably lower than or equal to 5°.

An immediately ional antifog coating is ed as soon as the surfactant 1O composition is applied, which ents one of the major advantages of the invention. Thus, it is not necessary to apply many times a surfactant on to score the antifogging effect, as is the case with products of the prior art.

In on, the antifogging effect provided by the antifog coating is long—lasting over time.

This durability is tested during fogging and defogging cycles, in a procedure described in the experimental section.

The antifog coating is temporary but easily renewable, since it just has to be performed a new application of surfactant when there are not sufficient surfactant molecules adsorbed onto the surface of the g coating precursor anymore. The latter therefore remains "activable" in alI circumstances.

The present invention also relates to a method for imparting antifog ties to an optical article, preferably a lens for spectacles, comprising the application of the surfactant- containing composition previously d, which is preferably a liquid solution, onto a main surface of said optical article, and more preferably using a tissue or cloth impregnated by a surfactant composition based on tants of a (VIII) such as described hereabove, and especially the non woven wet tissue or the dry microfiber tissue as bed above.

Preferably, the main surface of the optical article onto which said composition is applied has a static contact angle with water of 100° or less, preferably 90° or less, more preferably of more than 10° and of less than 50°. Said main surface is generally the e of a coating applied on the substrate of the optical article, eg. a precursor coating of an antifog coating.

Preferably, said main surface is not the surface of a hydrophobic and/or oleophobic coating. Said main surface can be the uncoated surface of the optical article's substrate.

In the present disclosure, a lens does possess antifogging properties if it sfully passes the breath test. For this test, the tester places the lens to evaluate at a distance of about 2 cm from his mouth. The tester for 3 seconds bIows his breath onto the exposed e of the lens. The tester can visually observe the presence or the absence of a condensation haze/distorsion.

A lens is considered as having antifogging properties if it inhibits the haze effect resulting from the fog at the end of the breath test (but it does not necessarily represent an antifog lensas described herein, because it may possibly present a visual distorsion leading to a visual acuity 40 <6/10).

Therefore, the method of the invention generally enables to provide gging properties to any type of optical article, preferably lenses for spectacles, whether the article has an antifog coating precursor coating, or not. The method is especially ended for treating bare lenses or lenses just coated with an abrasion-resistant coating, preferably of the loxane- containing type.

The present ion lastly relates to an optical article, preferably a lens for spectacles, comprising a substrate provided with a g comprising silanol groups on the surface thereof, a part of the e of said coating comprising silanol groups on the e thereof directly contacting an antifog coating precursor coating such as previously defined, and r part of 1O the surface of said coating comprising silanol groups on the surface thereof, preferably the remainder of its surface, being in direct contact with, and adhering to a hydrophobic and/0r oleophobic coating. These parts may be continuous or discontinuous.

Such an optical article can especially be used as a demonstrator for showing antifogging properties, after application on the surface thereof of a liquid solution comprising at least one surfactant and/or one hydrophilic compound with no surface active properties such as previously defined, then by submitting the e to fog generating conditions (breath, refrigerator, boiling water vapor...) or by submitting its surface to one or more wiping operations before being exposed to fog generating conditions.

The optical article mists on that part of the surface covered with the hydrophobic and/or oleophobic g and remains transparent in the area comprising the antifog g.

The hydrophobic and/0r oleophobic coatings, or antisoiling top-coats that can be suitably used in this optical article are especially described in the application . They differ naturally from the antifog coatings of the invention.

The hydrophobic and/or oleophobic coatings used preferably have a surface energy lower than or equal to 14 mJ/mz, preferably lower than or equal to 12 mJ/mz, in accordance with the Owens Wendt method described in the article referred to in the application W02010/055261.

Such optical articles can be manufactured according to any one of the s sed in WO 80472, which is hereby incorporated by reference.

The following examples illustrate the invention in a more detailed yet non limiting way.

EXAMPLES 1. Materials and optical es used Silica is used in the form of granules provided by the Optron lnc. company. The organosilane nd used in the examples to form the antifog coating precursor is 2— [methoxy(polyethyleneoxy)propyl]trimethoxysilane comprising from 6 to 9 ethylene oxide units, of formula (ill) and with a molecular weight 450-600 g/mol (CAS No.: 659534-072. Ref: SlM6492.7, ed by the Gelest, Inc. company).

The lens used comprises a lens substrate in an ORMA® material, comprising a polyurethane-based impact—resistant primer with a thickness of about 1 micron, itself provided 40 with an on-resistant coating with a ess of about 3 microns by depositing and curing a PCT/EP2012l062620 composition such as defined in example 3 of the patent EP 0614957, coated in turn with a five— Iayer antireflective coating Zr02/Si02/Zr02/ITO/Si02 (noted antireflective coating Y) deposited onto the on-resistant coating by ation under vacuum of the materials in the order in which they are mentioned (respective thicknesses of the layers: 29, 23, 68, 7 and 85 nm). An ITO layer is an electrically conductive layer of indium oxide doped with tin (ln20318n).

These lenses are treated on both faces according to the s described hereafter, the concave face being treated before the convex face.

In the examples, the antireflection coating is not submitted to any activating treatment prior to ting the antifog coating precursor. 2. Vapor tion of the antifog coating sor In the examples, the deposition is carried out on the antireflective g Y of a lens by evaporation under vacuum using a Joule effect—based heating source.

The siloxane compound of formula IIi is poured in a copper capsule (in the absence of any porous al), and this capsule is deposited onto a heating support in conductive tantalum. The evaporating device is a SATIS 1200 DLF or BALZERS BAK apparatus. The evaporation pressure of the siloxane compound of formula ”I does generally vary from 5.10“6 to 8.10'6 mbar for SATIS 1200 DLF. Once the evaporation is completed, the surface of each lens is rinsed with some soapy water, optionally with isopropyl alcohol, then deionized water and wiped with a CémoiTM dry cloth so that the excess of siloxane nd of formula III deposited be removed.

The CémoiTM cloth is a cloth provided by the Facoi supplier/retaiier under the reference Microfibre M 840 8 (30x40). 3. Application of a surfactant-containing liguid sqution (temporam antifog on} 3.1 Preparation of surfactant ons Two different surfactants were used: Capstone® FS 3100 is the surfactant used for ing the surfactant solutions of the invention. ne® FS 3100 is a surfactant comprising a compound of general formula F(CF2)y-(CH2- CH20)X+1H (VIII) for which more than 90% by weight corresponds to the fraction y=6 (even more than 95% by weight), x being an integer ranging from 1 to 14. In other words, Capstone® FS3100 is a mixture of compounds having polyethoxylated chains of variable length, but a fluorinated chain of constant length (y=6).

Capstone® F83100 contains trace amounts of compounds of formula (Vlll) in which y is higher than 6 (as impurities), which are not detectable through HPLC. The distribution of the ethoxy group as determined by HPLC-MS in the mixture of ne® FS 3100 compounds is as foIlows: x 1 and 2 3 4 5 6 7 8 Weioht % 28.2 20.5 19.1 14.65 9.35 4.95 2.2 Zonyl® FSO 100 (from DuPont) is used as a comparative tant. Zonyl® FSO 100 is a mixture of compounds of formula (Vlll) wherein y is equal to 6, 8 and 10 with weight s respectively of about 65%, 30% and 5%, and x is an integer ranging from 2 to 13.

A solution is prepared for each surfactant: the surfactant is dissolved in a mixture of deionized water and isopropyl alcohol (IPA), so as to obtain an s solution containing 2.5% by weight of IPA and 6% by weight of surfactant. 3.2. Deposition of the solution onto lenses The lenses provided with an antifog coating sor coating prepared under 2 were treated by means of the solutions bed under 3.1.

Each solution is applied as follows: 1. Stir the solution vial before use. 2. Hold the lens between the thumb and the forefinger and apply 2 drops of the surfactant solution on the center of the convex face of the lens. 3. Using a clean CémoiTM cloth (supplier Facol bre M 840 8 (30x40), spread the drops with the fingertip over all of the lens surface without rubbing (max 7 seconds). 4. Perform the same operation with the concave face of the lens.

. Allow drying for 5 to 10 seconds and control the lens, as for ission only, under the ambient light (ceiling light consisting in a neon tube), by keeping the lens at a distance from the eye of from 30 to 50 cm. 6. Using another clean CémoiTM cloth, wipe the edge of the lens. 7. Remove the white marks which are visible in transmission, the Cémoi TM cloth being held with the forefinger tip, without strongly rubbing. The lens should be clean and devoid of any white mark over its entire surface.

The method makes it possible to obtain a tly transparent ophthalmic lens. 4. Hot vagor test: All the vapor tests have been carried out on a 10 lens-panel: 5 pairs (or s) of lenses, each pair comprising one lens according to the invention (lens treated with the solution with 6% by 3O weight of Capstone® FS 3100) and one comparative lens (lens treated with the solution with 6% by weight of Zonyl® FSO 100).

Before the test, the lenses are placed for 24 hours in a temperature-regulated environment °C) and under 40 to 50% humidity.

For the test, the lenses are placed for 15 seconds above a heated container containing water at 52°C. Immediately after, a visual acuity scale located at a distance of 5 m is observed h the tested lens. The observer evaluates the visual acuity as a function of time and according to following criteria: 0. No fog, no visual distortion (visual acuity = 10/10) 1. Fog and/or visual distortion allowing a visual acuity > 6/10 40 2. Fog and/or visual distortion allowing a visual acuity < 6/1 0 In practical terms, to obtain the score 0 or 1, a wearer having a vision of 10/10 and having placed the lens in front of his eye should be able to distinguish the orientation of the "E" letters on the 6/10 line of the Snellen optotype table placed at a ce of 5 meters.

This test makes it possible to simulate the ordinary living conditions where a wearer leans his face towards a cup of tea/coffee or towards a pan filled with boiling water. if the lenses obtain a score of 0 or 1, they are submitted to a new vapor test after having controlled under a Waldmann lamp that they were totally dry.

The test is repeated for each couple of lenses until each lens obtains a score 2, meaning that it failed in the vapor test. 1O The results are given in the following table (Table 1): Stress number at Stress number at Stress number at l® Stress number at which Zon which Zonyl® which Capstone® which Capstone® FS- FSO-100 obtains FSO100 obtains the FS-3100 obtains the 3100 s the the score 2 score 2 (failure) Couple 1 Couple 2 An improvement in the durability towards vapor test could be noticed with the solution based Capstone® FS-3100 for 3 to 4 of the 5 treated lenses (stress number sed up to 40%), which is particularly important and surprising. For the other lenses, the performances of both surfactants are comparable.

. Tests under winter and tropical conditions These tests were performed using the system for determining the antifog performance of transparent optical articles that is fully bed in French patent application n" 11.53814 filed on May 4, 2011, and represented on figure 1 of said patent application, where it is d (20).

A lens passes the test when ing a sharpness cient N _>_ 0.6. A lens failed in this test when obtaining a sharpness coefficient N < 0.6. The sharpness coefficient N is defined in French patent application n° 11.53814. a) Winter conditions in this test, the lenses provided with an antifog coating precursor coating ed under 2 and further treated as described in 3.2 by means of the solutions described under 3.1 (or with the commercial Defog itTM on) were stored for 60 minutes under "winter ions" (4°C, 40% humidity) and were then rapidly subjected to normal conditions (20°C, 50% humidity). The results are shown below: (Table 2) Surfactant 30 wipings Defog itTM All pass All pass 1 pass, 1 fall zony' FSO‘1OO All pass All pass 1 pass 1 fail (2 lenses) ’ CapstoneQ FS A” 9353 A” pass All pass 3100 5 lenses) b) Tropical ions in this test, the lenses provided with an antifog coating precursor coating prepared under 2 and further treated by means of the ons described under 3.1 (or with the commercial Defog itlM solution) were stored for 30 s under normal conditions (20°C, 45% humidity) and were then rapidly ted to "tropical conditions" (30°C, 70% humidity). The results are shown below: Surfactant No wiping 1 1O win-ins Degog itTM All pass I All pass All pass zony' FSO'mO 1 pass, 1 fail ’ All fail All fail 2|enses Capstone F8 All pass I All pass 3 pass, 1 fail 3100 (5 lenses) 1 All pass Table 3 It can be concluded from these two series of tests that Capstone® FS—3100 (6% by weight) is or to Zonyl® FSO—100 (6% by weight) in terms of antifog performance, and comparable to 1O the Defog itTM commercial solution. 6. Durability of the gging effect after a mechanical stress (after application of a surfactant solution) This test enables to evaluate the resistance to wiping of the temporary anti—fog solution onto the surface of the lenses. It was carried out on several couple of lenses (2 lenses). The general test protocol is described in § 5 of the experimental part of .

Each couple of lenses was initially subjected to a series of 5 wipings, then 10, 10, 10, 20, 20 and additional wiping operations were med. Briefly, a hot vapor test followed by a drying step is carried out between each series of wipings. The test was generally stopped when at least one lens of a couple yielded a low score.

Here, a wiping operation corresponds to one moderately marked rotation of a wiping cloth CémoiTM on both faces of the lens (the lens is d between the thumb and the forefinger).

The antifog scores (A, B, C or D) correspond to the fog level at the end of each hot vapor test, after implementation of the corresponding number of wiping operations (cumulated number): A: Homogeneous water film (acuity 10/10) B: Visual distortion considered as acceptable by the wearer C: Visual distortion considered as not acceptable by the wearer (heterogeneous water film) D: y diffusing white haze, fine water drops.

The lenses are considered as having sfully passed the durability test if they obtained a score A or B.

Lenses G1 are lenses according to the present ion having an antireflection g and a precursor coating of an antifog coating. Lenses G1 are provided with an antifog coating precursor coating prepared under 2 and further d as described in 3.2 by means of the solutions described under 3.1, or similar solutions with a lower (3% wt) or higher (15% wt) amount of surfactant, keeping the amount of isopropyl alcohol at 2.5%. 2012/062620 Lenses 62 are lenses without antireflection coating and t precursor coating of an antifog coating. Lenses G2 are identical to those described in § 1, except that no antireflection coating was deposited onto the abrasion—resistant coating. The solutions described under 3.1 were directly deposited onto said abrasion-resistant coating, as described in 3.2.

The results are shown in the tables hereunder: . . Antifog score after X (cumulated) wiping lens um- 122' e1 Zonyl®6% mun 61 Capstone® F83100 3% 3' G1 Zonyl® 6% A A A 0 G1 Capstone® FS3100 3% A A A A 4' (31 Zonyl® 6% A --- G1 Capstone® F83100 3% A I -u-- ‘ Gt Zonyl® 6% B --- —Capstone®rssioos% 1:A ---- 2 2 —Zonyi®6% A A G1 Capstone® F831OO 6% A A A A A A G1 Zonyl® 6% A A A A A A —Capstone®r=sswo 6% -----n 11' _zony.®6% G1 ne® F831OO 15% A A A A A A A A G1 Zonyl® 6% A A A A A A A C Capstone® F83100 15%m- Table 4 Coup e nl o T ype of Antifog score after X (cumulated) wiping Surfactant containing solution operations with x: Zonyl® FSO-iOO 6% G2 Capstone® F83100 6% G2 Zonyl® FSO-1OO 6% G2 Capstone® F83100 6% Zonyl® FSO-1OO 6% 3" G2 ne® FS3100 6% A A B B G2 Zonyl® FSO-100 6% A A A B B D 4” c2 Capstone® FS31OO 6% A ’_A A A A A Zon |® 0 6% _---lil " Capstone® F83100 6% m.

Table 5 For lenses G1, it can be seen that the durability of antifog performance of ne® FS-3100 at 3% by weight after a ical stress is almost equivalent to that of Zonyl® FSO-1OO at 6% by weight. Both surfactants exhibit similar antifog performances when used at a weight content of For lenses G2, Capstone® FS—31OO is more effective than Zonyl® 0 at a weight content of 6%. However, the durability of the antifogging effect is lower due to the absence of precursor g of an antifog coating on lenses G2. 7. Evaluation of additional lenses and cosmetic aspect of the lenses Lens G1 is the lens according to the present invention that has been defined in § 6. Lens G3 is the antifog spectacle lens commercialized by Seiko, which comprises a substrate having a refractive index of 1.6 and a precursor coating of an antifog coating. Lens G4 is the antifog spectacle lens commercialized by Tokai, which comprises a ate having a tive index of 1O 1.6 and a precursor coating of an antifog coating.

Lenses G1, G3 and G4 were further treated as bed in 3.2 by means of the solution described under 3.1 comprising 6% by weight of ne® FS-3100.

They were subjected to one hot vapor test such as described previously ut wiping cycles), dried as in § 6, and then subjected to additional hot vapor test / drying cycles. Antifog scores were given to the lenses after each hot vapor test. The results are shown in the table below (Table 6).

Number of hot vapor tests Lens III- ---- All lenses G1, G3 and G4 after having been treated as described in 3.2 by means of the solution described under 3.1 comprising 6% by weight of Capstone® FS—3100 exhibit antifogging properties.

Lens G4 does not exhibit a actory antifog effect durability with the Capstone® FS- 3100 solution. Optical distortion is rapidly ed, and ic aspect after fogging is not acceptable. Indeed, the lens s whitish after deposition of the surfactant solution. After drying to evaporate the water film formed at the surface of the lens, spots appeared.

Lenses G1 and G3 demonstrate comparable antifog performance with the Capstone® FS—31OO solution. However, contrary to lens G1, cosmetic aspect after fogging of lens G3 is not acceptable. After drying to evaporate the water film formed at the surface of the lens, spots appeared.

Lens G1 did not exhibit cosmetic problems, before and after elimination of the excess of 3O the siloxane compound of formula III, even though several wiping cycles are perfomed in a durability test. After deposition of the surfactant on, the glide ability of a cloth on the surface of this lens was satisfactory and was the same using Zonyl® FSO-100 6% wt rather than ne® FS—31OO 6% wt. Further, the speed of evaporation of the water film formed at the surface of the lens after fogging was the same for both surfactants. In both cases, homogeneity of the water film was the same.

Claims (39)

What is claimed 1. is:

1. An l article comprising a substrate having at least one main surface coated with a first coating and, directly contacting this first coating, a precursor coating of an antifog coating, wherein the g precursor of the antifog coating: — is obtained through the ng of at least one organosilane compound having: 0 a polyoxyalkylene group, and 0 at least one silicon atom g at least one hydrolyzable group, - and is further coated with a film obtained by applying onto said precursor coating a 1O surfactant-containing composition containing at least one surfactant of a F(CF2)y—(CH2- CH20)X+1H (VIII), wherein x is an integer ranging from 1 to 14, y is an r lower than or equal to 10, compounds of formula (VIII) in which y=6 being present in an amount of at least 90% by weight relative to the weight of compounds (VIII) present in the composition, so as to form an antifog coating. 15

2. The l article of claim 1, wherein the polyoxyalkylene group comrpises less than 80 carbon atoms.

3. The optical article of claim 2, wherein the polyoxyalkylene group comprises less than 40 carbon atoms.

4. The l article of any one of claims 1 to 3, wherein the compounds of formual (VIII) in 20 which y=6 are present in an amount of at least 95% by weight.

5. The optical article of claim 4, wherein the compounds of formual (VIII) in which y=6 are present in an amount of 100% by weight.

6. The optical article of any one of claims 1 to 5, wherein the antifog coating has a static contact angle lower than or equal to 10°. 25

7. The optical article of claim 6, wherein the static contact angle is lower than or equal to 5°.

8. The optical article of any one of claims 1 to 7, wherein the surfactant-containing composition is a liquid n.

9. The optical article of any one of the preceding claims, wherein the compounds of formula (VIII), in which x ranges from 1 to 4, are present in an amount of at least 50% by weight, relative 30 to the weight of compounds (VIII) present in the surfactant-containing ition.

10. The optical e according to any one of the preceding claims, wherein the surfactant— containing composition comprises from 0.5 to 15% by weight of surfactants of formula (VIII), relative to the weight of said ition.

11. The optical article of claim 10, wherein the surfactant-containing composition comprises 35 from 2 to 8% by weight of tants of formula (VIII), relative to the weight of said composition.

12. The optical article according to any one of the preceding claims, n the compounds of formula (VIII), in which y is higher than 6, are present in an amount of less than 5% by weight, relative to the weight of compounds (VIII) present in the the surfactant-containing composition.

13. The optical article of claim 12, wherein the compounds of formula (VIII), in which y is higher than 6, are present in an amount of less than 2% by weight, relative to the weight of compounds (VIII) present in the the surfactant—containing composition.

14. The optical e of claim 12 or 13, wherein the compounds of formula (VIII), in which y is higher than 6, are present in an amount of 0% by weight, ve to the weight of compounds (VIII) present in the the surfactant-containing composition.

15. The optical article of any one of the preceding claims, wherein the first coating ses silanol groups on its surface.

16. The optical article of any one of the preceding claims, wherein the first coating is an 10 antireflective coating, an abrasion-resistant coating or a silica—based layer deposited onto an abrasion—resistant coating.

17. The optical article ing to any one of the preceding claims, wherein the coating precursor of the antifog coating has a thickness lower than or equal to 5 nm.

18. The optical article according to any one of the preceding , n the coating 15 precursor of the antifog coating has a static contact angle with water of more than 10° and of less than 50°.

19. The l e according to any one of the preceding claims, wherein the organosilane compound is a compound of formula: R1Ym8i(x)3-m (I) 20 wherein the Y groups, being the same or different, are monovalent organic groups bound to the silicon through a carbon atom, the X groups, being the same or different, are yzable groups, R1 is a group sing a polyoxyalkylene group, and m is an integer equal to 0, 1 or 2.

20. The optical article according to any one of the preceding claims, wherein the organosilane nd has a polyoxyalkylene group comprising from 5 to 20 carbon atoms. 25

21. The optical e of any one of the preceding claims, further defined as an ophthalmic lens.

22. A method for imparting antifog properties to an optical article having at least one main surface, comprising the application onto said main surface of a surfactant—containing composition such as defined in any one of claims 1 to 21. 30

23. The method of claim 22, wherein the application onto said main surface comprises wiping said main surface with a non woven tissue, whose structure comprises a hydrophilic polymer and a hydrophobic polymer, said tissue being impregnated with said surfactant—containing composition.

24. The method of claim 23, wherein the hilic polymer ses cellulosic units. 35

25. The method of claim 22, wherein the application onto said main surface comprises wiping said main surface with a dry microfiber tissue obtained by impregnation, with said surfactant containing ition, of a microfiber tissue comprising microfibers made of polymers comprising ter units and polyamide units, followed by drying said microfiber tissue.

26. The method of any one of claims 22 to 25, wherein the main surface of the optical article has a static contact angle with water of 100° or less before applying said surfactant-containing composition.

27. The method of claim 26, wherein the static t angle with water is 90° or less.

28. The method of claim 26, wherein the static contact angle with water is more than 10° and less than 50°.

29. The method of any one of claims 22 to 28, wherein the optical e ses a substrate having at least one main surface coated with a precursor coating of an antifog coating, and wherein the coating precursor of the antifog coating is ed through the grafting of at 10 least one organosilane compound having: 0 a polyoxyalkylene group, and c at least one silicon atom bearing at least one hydrolyzable group.

30. The method of claim 29, wherein the polyoxyalkylene group comprises less than 80 carbon atoms. 15

31. The method of claim 29 or 30, wherein the yalkylene group ses less than 40 carbon atoms.

32. A non woven wet tissue whose structure comprises a hydrophilic polymer and a hydrophobic polymer, said tissue being impregnated by a surfactant-containing composition such as d in any one of claims 1 to 21. 20

33. The non woven wet tissue of claim 32, wherein the hydrophilic polymer comprises cellulosic units.

34. A dry microfiber tissue obtained by impregnation, with a surfactant containing composition such as defined in any one of claims 1 to 21, of a microfiber tissue comprising microfibers made of polymers comprising polyester units and polyamide units, followed by drying said microfiber 25 tissue.

35. The l article of claim 1, substantially as herein described with reference to any one of the Examples thereof.

36. The optical article of any one of claims 1 to 21, ntially as herein described.

37. The method of any one of claims 22 to 31, substantially as herein described. 30

38. The non woven wet tissue of claim 32 or 33, substantially as herein described.

39. The dry microfiber tissue of claim 34, substantially as herein described.