WO2021232218A1

WO2021232218A1 - Spectacle lens with antifogging properties

Info

Publication number: WO2021232218A1
Application number: PCT/CN2020/090971
Authority: WO
Inventors: Liu OUYANG; Norbert Hugenberg; Songjin ZHANG
Original assignee: Carl Zeiss Vision International Gmbh; Carl Zeiss Vision Technical Services ( Guangzhou) Ltd.
Priority date: 2020-05-19
Filing date: 2020-05-19
Publication date: 2021-11-25
Also published as: WO2021234032A1; CN115777074A

Abstract

A spectacle lens with antifogging properties and a method of manufacturing thereof are provided. The spectacle lens comprises at least one spectacle lens substrate and at least one coating. The spectacle comprises at least one anti-fog coating and at least one clean coating, the at least one clean coating being the outermost layer thereof.

Description

Spectacle lens with antifogging properties

The present invention relates to a spectacle lens with antifogging properties and a method of manufacturing thereof.

When the surface temperature of optical articles decreases below the dew point of the environment, optical articles such as spectacle lenses are often covered with fog. Under a microscope the fog comprises many tiny water droplets that lead to a decrease in transparency due to the diffusion of light.

The fogging phenomena is caused by the formed and grown droplets from condensed water. K. Rykaczewski, Microdroplet Growth Mechanism during Water Condensation on Superhydrophobic Surfaces, Langmuir 2012, 28, 7720-7729, has shown that the droplets formed started from a close to submicron size and grew to a micron size on non-hydrophilic surface, which leads to a decrease in transparency due to the diffusion of light.

Safety glasses, sport glasses, sunglasses or shields with permanent antifogging properties are commercially available. However, as those glasses or shields usually comprises no antireflective coating, they are usually not very durable in a real wearing environment in terms of scratches and abrasions. To provide a satisfactory antifogging performance, anti-fog coatings are mostly of hydrophilic nature, easy to get dirty and poor to abrasion and scratches. Therefore, even in case a permanent anti-fog coating is applied, the anti-fog coating is often not durable enough in real wearing environment where spectacle lenses continue absorbing moisture and undergo frequent lens cleaning and wiping. Further, wearers of corrective lenses, i.e. lenses with dioptric power according to section 3.5.3 of DIN EN ISO 13666: 2019-12, compared to users of safety glasses may have a much higher expectation on clear vision and wear durability. A spectacle lens with a permanent anti-fog coating that comprises no antireflective coating, or with an antireflective coating and a non-permanent anti-fog coating, may not be accepted of a wearer of corrective lenses.

Ophthalmic lenses, in particular spectacle lenses, with antifogging properties may be prepared by dip or spin coating an ophthalmic lens substrate in a highly hydrophilic water-absorbing resin, such as for example a polyvinyl alcohol, a (sodium) polyacrylate, or a polyurethane containing hydrophilic groups, resulting after curing in an anti-fog coating of a thickness of 3 μm to 10 μm. As mentioned above, the anti-fog coating may have a significant reduced resistance to scratches and abrasions. Additionally, the hydrophilic surface of the anti-fog coating may make it very unfavorable for lens cleaning and wiping.

For ophthalmic lenses, in particular spectacle lenses, a temporary anti-fog coating may be used in combination with an antireflective coating, the anti-fog coating being adjacent to the antireflective coating, either on top of or below the antireflective coating. However, an anti-fog coating on top of an antireflective coating typically shows poor wear durability while an anti-fog coating below an antireflective coating can cause issues on antireflective performance and antireflective durability.

US 2013/0308189 A1 discloses an optical component having a cross-linked anti-fog coating obtainable by covalent attachment of a silane derivative to the surface of the optical component. The silane derivate may be a halosilane or an alkoxysilane functionalized with a terminal hydrophilic group. The terminal hydrophilic group is crosslinked to at least one hydrophilic group of an adjacent silane derivative of the anti-fog coating.

US 2017/0297955 A1 discloses a process for producing an optical glass with an anti-fog coating. This process comprises the preparation of a layer having Si-H groups on the optical glass followed by the reaction of said Si-H groups with a compound having hydrophilic groups and at least one group reactive to the Si-H group, for example at least one reactive C=C double bond. The Si-H groups may be prepared by applying a halosilane, by applying SiO _x under reducing conditions in the presence of hydrogen or by reducing Si-O groups on the surface of the optical glass with radical hydrogen.

US 2012/0028005 A1 discloses an optical article comprising a substrate and on at least one face of the substrate a multilayered antireflective coating functioning in an interferential manner having antifog properties. The last layer of the antireflective coating comprises a layer-by-layer (LbL) coating exposed to environment, wherein the LbL coating consists of a least two bilayers. The bilayers are formed by successively applying a first layer composition and second layer composition, each comprising a superabsorbent polyelectrolyte, acolloid of nanoparticles of metal oxide or silicon oxide, or a mixture thereof, with the proviso that at least one of the layer compositions comprises a superabsorbent polyelectrolyte. A hand wiping test is applied to the optical article, which includes hand-wiping with a dry microfiber cloth for 20 strokes and a visual inspection. The optical article passes, if the coating remains the initial antireflecting color and no fog by breathing.

US 2009/0053465 A1 discloses an optical element comprising in the following order a glass substrate, a water absorbing first layer and a second layer. Blind holes are formed in the water absorbing first layer and in the second layer. The blind holes commence from the surface of the second layer, extend completely through the second layer and at least partially through the water absorbing first layer. The second layer may be i) an anti-reflection coating, a mirror coating or a hard layer; ii) a composite or combination of a hard layer and an anti-reflection coating; or iii) a composite or combination of hard layer and a mirror coating. The optical element, in particular a spectacle lens, exhibits an anti-fogging effect.

US 2019/0056529 A1 discloses a coating for an optical article. The coating comprises a bottom coating comprising at least one hydrophilic resin binder, forming an anti-fogging layer, and a top coating overlying the bottom coating, forming an anti-reflective layer. The top coating comprises nanopores of less than 150 nm pore size.

IN 201721011814 A discloses an anti-glare, anti-fog coating composition prepared from a sol-gel, the sol-gel comprising a precursor solution prepared from a mixture comprising 1: 1: 3 ratio of hexadecyltrimethoxysilane (HDTMS) , glycidoxypropyltrimethoxysilane (GPTMS) , tetraethoxyorthosilicate (TEOS) ; asolvent; an aqueous acid solution; across linking agent;

an acid catalyst; and a silicone-based wetting additive. IN 201721011814 A further discloses a method of imparting scratch resistance, hydrophobic, anti-glare and anti-fog properties to a substrate comprising applying a scratch resistant coating composition, a hydrophobic coating composition, an anti-glare, anti-fog coating composition to at least one side of the substrate.

CN 110187416 A discloses a spectacle lens comprising an anti-fog coating. The anti-fog coating is overcoated with an anti-oil coating.

P.M. Bhada, “How Weld Hose Materials Affect Shielding Gas Quality” , Welding Journal, July 1999, pp. 35-40, discloses in table 2 permeability coefficient of common polymers, such as poly (vinylchloride) , poly (ethylene) of high and low density, poly (propylene) or poly (carbonate) .

Very recently, the outbreak of COVID-19 makes more and more people wear mask to prevent virus transmission. In China more than 80%of the population is wearing masks every day. However, for people who simultaneously wear a spectacle, the mask can cause the spectacle lenses to fog up with every breath because of the hot air breathing through nose and/or mouth and reaching the mostly concave back surface of the spectacle lenses.

In case the coating of a spectacle lens comprises at least one antireflective coating and at least one anti-fog coating, the at least one anti-fog coating being the outermost coating, a long-lasting or durable functionality of the anti-fog coating is currently not achievable. Known hydrophilic compositions resulting in at least one anti-fog coating are typically applied on top of the at least one antireflective coating in an optical thickness below 10 nm to avoid disturbing the antireflective properties of the at least one antireflective coating underneath and to function as at least one anti-fog coating. To function as at least one anti-fog coating means in principle to induce spreading of condensed water droplets to generate a homogeneous water film on top of the at least one anti-fog coating. Both the low coating thickness of the at least one anti-fog coating and its inability to absorb a significant amount of water are thought by the inventors to be the root causes for the inferior durable antifogging performance of known anti-fog coatings. Further, because of the hydrophilic nature of known anti-fog coatings, the spectacle lens may be poorly resistance to contaminations and unfavorable to lens cleaning and wiping.

In case the coating of a spectacle lens comprises at least one antireflective coating and at least one anti-fog coating, the at least one antireflective coating being the outermost coating, the antireflective performance of the at least one antireflective layer may be impaired in optical and mechanical aspects.

In case the coating of a spectacle comprises at least one anti-fog coating and no antireflective coating, the at least one anti-fog coating being the outermost coating, the spectacle lens, as mentioned above, may have a reduced resistance to scratches and abrasions and may be unfavorable to lens cleaning and wiping.

To meet all these requirements and to overcome the drawbacks of the permanent or non-permanent anti-fog coatings of the state of the art, it is therefore an object of the present application to provide a spectacle lens with long term antifogging functionality without comprising a spectacle lens wearers’ expectation on the durability of the spectacle lens or on the transmission of the spectacle lens for clear vision.

This object has been solved by the spectacle lens according to claim 1 and a method for manufacturing the spectacle lens according to claim 13. Preferred embodiments, which might be realized in an isolated fashion or in any arbitrary combination, are listed in the dependent claims.

The co-existance of at least one anti-fog coating and at least one clean coat layer, preferably the co-existance of at least one anti-fog coating adjacent to at least one clean coat layer is thought to be the reason for the long-lasting functionality of the at least one anti-fog coating. Further, due to that co-existance at least one slippery surface is created on top of the spectacle lens. The at least one slippery surface each being the outermost surface of the spectacle lens is thought to be responsible to improve the resistance to contaminations and to ease lens cleaning and wiping. In case the coating of the spectacle lens further comprises at least one antireflective coating the desired antireflective properties are preferably not impaired by the at least one anti-fog coating and the at least one clean coat layer.

As spectacle lens substrate an uncoated or precoated blank, the blank being defined in section 3.8.1 of DIN EN ISO 13666: 2019-12 as piece of optical material with one optically finished surface for the making of a lens; an uncoated or precoated single-vision blank, the single-vision blank being defined in section 3.8.2 of DIN EN ISO 13666: 2019-12 as blank with the finished surface having a single nominal surface power; an uncoated or precoated multifocal blank, the multifocal blank being defined in section 3.8.3 of DIN EN ISO 13666: 2019-12 as blank with the finished surface having two or more visibly divided portions of different dioptric powers or focal powers; an uncoated or precoated progressive-power blank, the progressive-power blank being defined in section 3.8.5 of DIN EN ISO 13666: 2019-12 as power-variation blank where the finished surface is a progressive-power surface; an uncoated or precoated degressive-power blank, the degressive-power blank being defined in section 3.8.6 of DIN EN ISO 13666: 2019-12 as power-variation blank where the finished surfaces is a degressive-power surface; an uncoated or precoated finished lens, the finished lens being defined in section 3.8.7 of DIN EN ISO 13666: 2019-12 as lens of which both sides have their final optical surface; an uncoated or precoated uncut lens, the uncut lens being defined in section 3.8.8 of DIN EN ISO 13666: 2019-12 as finished lens prior to edging; or an uncoated or precoated edged lens, the edged lens being defined in section 3.8.9 of DIN EN ISO 13666: 2019-12 as finished lens edged to final size and shape may be used. If one of the before mentioned blanks is precoated, the respective finished surface comprises at least one coating. If one of the before mentioned lenses is precoated, at least one side thereof comprises at least one coating.

Preferably, the spectacle lens substrate is an uncoated or precoated finished lens or an uncoated or precoated uncut lens.

The uncoated or precoated spectacle lens substrate may be classified as afocal lens with nominally zero dioptric power according to section 3.6.3 of DIN EN ISO 13666: 2019-12 or as corrective lens, i.e. as a lens with dioptric power according to section 3.5.3 of DIN EN ISO 13666: 2019-12.

Further, the uncoated or precoated spectacle lens substrate may be classified as single-vision lens according to section 3.7.1 of DIN EN ISO 13666: 2019-12; as position-specific single-vision lens according to section 3.7.2 of DIN EN ISO 13666: 2019-12; as multifocal lens according to section 3.7.3 of DIN EN ISO 13666: 2019-12; as bifocal lens according to section 3.7.4 of DIN EN ISO 13666: 2019-12; as trifocal lens according to section 3.7.5 of DIN EN ISO 13666: 2019-12; as fused multifocal lens according to section 3.7.6 of DIN EN ISO 13666: 2019-12; as power-variation lens according to section 3.7.7 of DIN EN ISO 13666: 2019-12; as progressive-power lens according to section 3.7.8 of DIN EN ISO 13666: 2019-12; or as degressive-power lens according to section 3.7.9 of DIN EN ISO 13666: 2019-12.

Further, the uncoated or precoated spectacle lens substrate may be classified as protective lens according to section 3.5.4 of DIN EN ISO 13666: 2019-12; as absorptive lens according to section 3.5.5 of DIN EN ISO 13666: 2019-12; as tinted lens according to section 3.5.6 of DIN EN ISO 13666: 2019-12; as clear lens according to section 3.5.7 of DIN EN ISO 13666: 2019 12; as uniformly tinted lens according to section 3.5.8 of DIN EN ISO 13666: 2019-12; a gradient-tinted lens according to section 3.5.9 of DIN EN ISO 13666: 2019-12; as double gradient-tinted lens according to section 3.5.10; as photochromic lens according to section 3.5.11 of DIN EN ISO 13666: 2019-12; or as polarizing lens according to section 3.5.12 of DIN EN ISO 13666: 2019-12.

The uncoated or precoated spectacle lens substrate is preferably based on an optical material, the optical material being defined according to section 3.3.1 of DIN EN ISO 13666: 2019-12 as transparent material capable of being manufactured into optical components. The uncoated or precoated spectacle lens substrate may be made of mineral glass according to section 3.3.1 of DIN EN ISO 13666: 2019-12 and/or of an organic hard resin such as a thermosetting hard resin according to section 3.3.3 of DIN EN ISO 13666: 2019-12; a thermoplastic hard resin according to section 3.3.4 of DIN EN ISO 13666: 2019-12; or a photochromic material according to section 3.3.5 of DIN EN ISO 13666: 2019-12.

Preferably, the uncoated or precoated spectacle lens substrate is based on one of the optical materials mentioned in table 1, particularly preferred one of the organic hard resins.

Table 1: Examples of optical materials for blanks or lenses

*Based on sodium D line

In case, the uncoated or precoated spectacle lens substrate is made of mineral glass and of an organic hard resin such as a thermosetting hard resin or a thermoplastic hard resin, the mineral glass preferably comprises at least one ultrathin lens. In this case, the organic hard resin may comprise an uncoated or precoated blank, an uncoated or precoated single-vision blank, an uncoated or precoated multifocal blank, an uncoated or precoated power-variation blank, an uncoated or precoated progressive-power blank, an uncoated or precoated degressive-power blank, an uncoated or precoated finished lens, an uncoated or precoated uncut lens; or an uncoated or precoated edged lens, each blank comprising on at least the finished surface thereof at least one ultrathin lens and each finished lens comprising on at least one side thereof at least one ultrathin lens. After surfacing the opposite surface of the respective blank, this opposite surface may comprise at least one ultrathin lens as well, the at least one ultrathin lens being identical or different to the other one in relation to the glass composition, to the average thickness and/or to the shape. Further, the spectacle lens substrate may be made of at least two ultrathin lenses comprising a plastic film in-between. The at least one ultrathin lens may be based on various glass compositions, for example, be borosilicate glass, aluminium borosilicate glass or alkali-free borosilicate glass. Preferably, the at least one ultrathin lens is based on a borosilicate glass or an aluminium borosilicate glass. The at least one ultrathin lens preferably has an average thickness in a range from 10 μm to 1000 μm, further preferably from a range from 13 μm to 760 μm, further preferably from a range from 16 μm to 510 μm, more preferably from a range from 18 μm to 390μm and most preferably from a range from 19 μm to 230 μm. Especially preferably, the at least one ultrathin lens has an average thickness in a range from 21 μm to 121 μm or from 75 μm to 140 μm or from 80 μm to 220 μm. The average thickness of the at least one ultrathin lens is understood to mean the arithmetic average. Below an average thickness of 10 μm, the at least one ultrathin lens is too mechanically unstable to be able to be combined with at least one of the surfaces of at least one of the organic hard resin components mentioned before. Above an average thickness of 1000 μm, the at least one ultrathin lens can lead to spectacle lenses that would have too great an edge thickness or too great a middle thickness of the spectacle lens. The average thickness of the at least one ultrathin lens is measured preferably with the Filmetrics F10-HC instrument from Filmetrics Inc. The at least one ultrathin lens preferably has a surface roughness Ra of < 1 nm. Further preferably, the surface roughness Ra of the at least one ultrathin lens is within a range from 0.1 nm to 0.8 nm, more preferably within a range from 0.3 nm to 0.7 nm and most preferably within a range from 0.4 nm to 0.6 nm. The aforementioned values for surface roughness Ra are each based on the front surface and the back surface of the at least one ultrathin lens of an unformed, planar ultrathin lens. After forming, the aforementioned values are in each case applicable preferably to that surface of the ultrathin lens that has not been brought into contact with the shaped body. Depending on the shaped body used for forming, the aforementioned values may also be applicable to the surface of the at least one ultrathin lens that was in contact with the shaped body used for forming. The surface roughness Ra of the at least one ultrathin lens is preferably determined by means of white light interferometry, preferably with the NewView 7100 instrument from Zygo Corporation. Ultrathin lenses are commercially available, for example, under the names: D 263 T eco, D 263 LA eco, D 263 M, AF 32 eco, SCHOTT AS 87 eco, B 270 I, each from Schott AG, or Corning Willow Glass or Corning Gorilla Glass, each from Corning Inc.

In case the spectacle lens substrate is made of an organic hard resin, preferably at least one of the finished surfaces of the spectacle lens substrate comprises at least one hard coating. The at least one finished surface of the spectacle lens substrate may be uncoated or precoated. The at least one hard coating preferably has an average thickness in a range of from 0.6 μm to 10μm, further preferably in a range of from 0.8 μm to 6.6 μm, more preferably in a range of from 1.1 μm to 5.8 μm and most preferably in a range of from 1.6 μm to 4.9 μm. The average thickness of the at least one hard coating is preferably determined by the measurement of the spectral reflectivity and/or the spectral transmissivity. The average thickness is the arithmetic average of the physical thickness of the at least one hard coating measured in at least three positions of the primer coating after application and curing. Preferably, an optical spectrometer, such as one of the devices F20, F10-HC or F10-AR of the company Filmetrics Inc., preferably the device F10-HC, is used to determine the average thickness of the at least one hard coating. Illumination of a spectacle lens comprising a spectacle lens substrate and at least one hard coating with white light causes interference spectra dependent on the physical thickness of the at least one hard coating and the respective refractive index thereof. The path difference corresponds exactly to the multiple of the optical thickness. The average thickness is preferably calculated with Fast Fourier Transformation (FFT) . Alternatively, the average thickness of the at least one hard coating may be determined with at least one scanning electron microscope photograph of a cross-section of the spectacle lens comprising a spectacle lens substrate and at least one hard coating. The thickness of the at least one hard coating is therefore determined in at least three positions and the arithmetic average is formed thereof.

The at least one hard coating may be based on at least one of the coating compositions disclosed in US 2005/0171231 A1, in US 2009/0189303 A1 or in US 2002/0111390 A1.

The at least one hard coating preferably is made of a coating composition disclosed in EP 2 578 649 A1, particularly in EP 2578 649 A1, claim 1. The coating composition configured to produce the at least one hard coating preferably comprises

A) a) at least one silane derivative of the formula (I) Si (OR ¹) (OR ²) (OR ³) (OR ⁴) , wherein R ¹, R ², R ³ and R ⁴, which may be the same or different, are selected from an alkyl, an acyl, an alkyleneacyl, a cycloalkyl, an aryl or an alkylenearyl group, each of which may optionally be substituted, and/or

b) at least one hydrolysis product of the at least one silane derivative of the formula (I) , and/or

c) at least one condensation product of the at least one silane derivative of the formula (I) , and/or

d) any mixture of the components a) to c) thereof;

B) a) at least one silane derivative of the formula (II) R ⁶R ⁷ _3-nSi (OR ⁵) _n, in which R ⁵ is selected from an alkyl, an acyl, an alkyleneacyl, a cycloalkyl, an aryl or an alkylenearyl group, each of which may optionally be substituted, R ⁶ is an organic radical containing an epoxide group, R ⁷ is selected from an alkyl, a cycloalkyl, an aryl or an alkylenearyl group, each of which may optionally be substituted, n is 2 or 3; and/or

b) at least one hydrolysis product of the at least one silane derivative of the formula (II) , and/or

c) at least one condensation product of the at least one silane derivative of the formula (II) , and/or

d)any mixture of the components a) to c) thereof;

C) at least one colloidal inorganic oxide, hydroxide, oxide hydrate, fluoride and/or oxyfluoride;

D) at least one epoxide compound having at least two epoxide groups; and

E) at least one catalyst system comprising at least one Lewis acid and at least one thermolatent Lewis acid-base adduct.

The term “at least one hydrolysis product” of the at least one silane derivative of the formula (I) or (II) respectively expresses the fact that the at least one silane derivative of the formula (I) or of the formula (II) each has already been at least partly hydrolyzed to form silanol groups.

The term “at least one condensation product” of the at least one silane derivative of the formula (I) or of the formula (II) respectively expresses the fact that a certain degree of crosslinking has also already taken place through condensation reaction of the silanol groups.

The at least one silane derivative of the formula (I) may be selected from tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, tetrabutoxysilane, tetraisobutoxysilane, tetrakis (methoxyethoxy) silane, tetrakis (methoxypropoxy) silane, tetrakis (ethoxyethoxy) silane, tetrakis (methoxyethoxyethoxy) silane, trimethoxyethoxysilane, dimethoxydiethoxysilane or mixtures thereof.

The at least one silane derivative of the formula (II) may be selected from 3-glycidoxymethyl-trimethoxysilane, 3-glycidoxypropyltrihydroxysilane, 3-glycidoxypropyldimethylhydroxysilane, 3-glycidoxypropyldimethylethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyl-trimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyldimethoxymethylsilane, 3-glycidoxypropyldiethoxymethylsilane, 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane or mixtures thereof.

The at least one colloidal inorganic oxide may be selected from silicon dioxide, titanium dioxide, zirconium dioxide, tin dioxide, antimony oxide, aluminum oxide or mixtures thereof.

The mean particle diameter of the at least one colloidal inorganic oxide, hydroxide, fluoride or oxyfluoride is preferably selected such that the transparency of the at least one hard coating is not affected. Preferably, the at least one colloidal inorganic oxide, hydroxide, oxide hydrate, fluoride and/or oxyfluoride has a mean particle diameter in the range of from 2 nm to 150 nm, even more preferably of from 2 nm to 70 nm. The mean particle diameter is determined preferably by means of dynamic light scattering. The at least one colloidal inorganic oxide, hydroxide, oxide hydrate, fluoride or oxyfluoride contributes to an increase in scratch resistance through incorporation into the existing network. In addition, selection of at least one colloidal inorganic oxide, hydroxide, oxide hydrate, fluoride or oxyfluoride allows the refractive index of the at least one hard coating to be matched to the refractive index of the uncoated spectacle lens substrate or to a precoating of the spectacle lens substrate.

The at least one epoxide compound having at least two epoxide groups is preferably a polyglycidyl ether compound, more preferably a diglycidyl ether or triglycidyl ether compound. For example, as at least one epoxide compound comprising at least two epoxide compounds digylcidyl ether, ethylenglycoldiglycidyl ether, propylenglycoldiglycolglycidyl ether, 1, 4-butandioldiglycidyl ether, 1, 6-hexandioldiglycidyl ether, trimethylolpropantriglycidyl ether, triglycidylglycerin and/or trimethylolethantriglycidylether may be used in the coating composition. Preferably, the at least epoxide compound comprises trimethylolpropantriglycidyl ether, butandioldiglycidyl ether and/or 1, 6-hexandioldiglycidyl ether.

The at least one catalyst system comprising at least one Lewis acid and at least one thermolatent Lewis acid-base adduct enables very homogeneous crosslinking and hence also constantly high strength over the entire layer thickness of the at least one hard coating. The term "Lewis acid" relates to an electrophilic electron pair acceptor compound, the term “Lewis base” is understood to mean an electron pair donor compound. The at least one Lewis acid is preferably one which have catalytic activity even at relatively low temperatures, for example at room temperature. The at least one Lewis acid may be selected from ammonium salts, metal salts (especially of metals from one of groups 1 (i.e. alkali metal salts) , 2 (i.e. alkaline earth metal salts) or 13 (preferably Al or B) of the periodic table of the elements, halides of an element of group 13 of the periodic table of the elements (especially AIX ₃ or BX ₃ where X is chlorine or fluorine) , organic sulphonic acids and amine salts thereof, alkali metal or alkaline earth metal salts, for example alkali metal or alkaline earth metal salts of carboxylic acids, fluoride salts, organotin compounds, or a mixture thereof. Preferred metal salts of metals from one of groups 1, 2 and 13 of the periodic table of the elements are, for example, perchlorates or carboxylates (i.e. carboxylic salts) . Preferred Lewis acids are, for example, ammonium perchlorate, magnesium perchlorate, sulphonic acids and salts thereof, such as trifluoromethanesulphonic acids and salts thereof.

The at least one Lewis acid-base adduct is understood to mean a compound which has catalytic activity with regard to the chemical reaction in question only at relatively high temperatures, while it is essentially still catalytically inactive at room temperature. Only through the supply of sufficient thermal energy is a thermolatent catalyst compound converted to a catalytically active state.

The at least one silane derivative of the formula (I) and/or the at least one hydrolysis product of the silane derivative of the formula (I) and/or the at least one condensation product of the silane derivative of the formula (I) is/are preferably present in the coating composition in an amount of 5%by weight to 50%by weight, more preferably of 5%by weight to 20%by weight. The amounts given before apply with regard to the at least one silane derivative of the formula (I) , with regard to the at least one hydrolysis product of the formula (I) , with regard to the at least one condensation product of the formula (I) or with regard to any mixture thereof. The amounts given before apply as well with regard to a mixture of silane derivatives of the formula (I) , with regard to a mixture of hydrolysis products of the at least one silane derivative of the formula (I) , with regard to a mixture of condensation products of the at least one silane derivative of the formula (I) or with regard to any mixture thereof.

The at least one silane derivative of the formula (II) and/or the at least one hydrolysis product of the silane derivative of the formula (II) and/or the at least one condensation product of the silane derivative of the formula (II) is/are preferably present in the coating composition in an amount of 5%by weight to 50%by weight, more preferably of 5%by weight to 20%by weight. The amounts given before apply with regard to the at least one silane derivative of the formula (II) , with regard to the at least one hydrolysis product of the formula (II) , with regard to the at least one condensation product of the formula (II) or with regard to any mixture thereof. The amounts given before apply as well with regard to a mixture of silane derivatives of the formula (II) , with regard to a mixture of hydrolysis products of the at least one silane derivative of the formula (II) , with regard to a mixture of condensation products of the at least one silane derivative of the formula (II) or with regard to any mixture thereof.

The weight ratio of the at least one silane derivative of the formula (I) , the at least one hydrolysis product of the silane derivative of the formula (I) and/or the at least one condensation product of the silane derivative of the formula (I) relative to the at least one silane derivative of the silane derivative of the formula (II) , the at least one hydrolysis product of the silane derivative of the formula (II) and/or the at least one condensation product of the silane derivative of the formula (II) is preferably in the range of from 95/5 to 5/95, more preferably in the range of from 70/30 to 30/70, even more preferably in the range of from 60/40 to 40/60.

The at least one colloidal inorganic oxide, hydroxide, fluoride and/or oxyfluoride is preferably present in an amount of 5%by weight to 50%by weight, more preferably of 5%by weight to 25%by weight, based on the total weight of the coating composition. The amounts mentioned before apply for one type of colloidal oxide, one type of hydroxide, one type of fluoride, one type of oxyfluoride, for a mixture thereof, for a mixture of different colloidal oxides, a mixture of different colloidal hydroxides, a mixture of different colloidal fluorides, a mixture of different colloidal oxyfluorides or for a mixture thereof. The mixture of different colloidal oxides, hydroxides, fluorides or oxyfluorides may for example comprises one type of each in different particle sizes or different types of each in the same or in a different particle size.

The at least one epoxide compound having at least two epoxide groups is preferably present in an amount of 0.1%by weight to 10%by weight, more preferably of 0.5%by weight to 10%by weight, based on the total weight of the coating composition. The amounts given before apply with regard to one type of epoxide compound or to a mixture of different types of epoxide compounds.

The at least one catalyst system is preferably present in an amount in the range from 0.01%by weight to 5%by weight, more preferably in the range from 0.1%by weight to 3%by weight, based on the total weight of the coating composition.

The weight ratio of at least one Lewis acid to the at least one thermolatent Lewis acid-base adduct is preferably in the range from 20/1 to 1/2, more preferably from 5/1 to 2/1.

The coating composition comprises at least one solvent comprising at least one alcohol, at least one ether, at least one ester or water. In case the at least one solvent comprises two different solvents, the boiling point of the first solvent S1 and the boiling point of the second solvent S2 is either S1/S2 ≥ 1.2 or S1/S2 ≤ 0.8. Further, in case the at least one solvent comprises two different solvents, the weight ratio of the first solvent to the second solvent is preferably in the range of from 5 to 0.01, more preferably in the range of from 2 to 0.2.

Preferably water is present in an amount of 2%by weight to 15%by weight, based on the total weight of the coating composition.

The components of the coating composition resulting in a hard coating are used in that they add to 100%by weight based on the total weight of the coating composition.

The coating composition mentioned before resulting in at least one hard coating is preferably applied to at least one of the coated or uncoated surfaces of the spectacle lens substrate by dip coating or by spin coating.

The use of the above mentioned coating composition comprising the components (A) to (E) , i.e. at least one silane derivative of formula (I) , at least one hydrolysis product and/or at least one condensation product thereof, at least one second silane derivative of formula (II) , at least one hydrolysis product and/or at least one condensation product thereof, at least one colloidal inorganic oxide, hydroxide, fluoride or oxyfluoride, at least one epoxide compound and at least one catalyst system, enables the production of at least one hard coating having very good adhesive strength on different uncoated or precoated spectacle lens substrates, having a high hardness, being of high scratch resistance and showing a low tendency to crack formation on different uncoated or precoated spectacle lens substrates.

Alternatively or additionally to the before mentioned coating composition resulting in a hard coating, at least one of the finished surfaces of the uncoated or precoated spectacle lens substrate, comprises at least one hard coating which is preferably based on a coating composition comprising

A) a) at least one silane derivative of the formula (III) R ¹R ² _3-nSi (OR ³) _n, wherein R ¹ comprises an alkyl group, a cyclo alkyl group, an acyl group, an aryl group or an hetero aryl group, each of which may be substituted, R ² is an organic rest comprising an epoxide group, R ³ comprises an alkyl group, a cyclo alkyl group, an aryl group or a hetero aryl group, each of which may be substituted, n = 2 or 3, and/or

b) at least one hydrolysis product of the silane derivative of the formula (III) , and/or

c) at least one condensation product of the silane derivative of the formula (III) , and/or

d) any mixture of components a) to c) ;

B) at least one colloidal inorganic oxide, hydroxide, oxide hydrate, fluoride and/or oxyfluoride;

C) at least one epoxy component comprising at least two epoxy groups; and

D) at least one catalyst system comprising at least one Lewis acid and at least one thermolatent Lewis base-adduct.

The term “at least one hydrolysis product” of the at least one silane derivative of the formula (III) the fact that the at least one silane derivative of the formula (III) has already been at least partly hydrolyzed to form silanol groups.

The term “at least one condensation product” of the at least one silane derivative of the formula (III) expresses the fact that a certain degree of crosslinking has also already taken place through condensation reaction of the silanol groups.

The at least one silane derivative of the formula (III) and/or the at least one hydrolysis product of the silane derivative of the formula (III) and/or the at least one condensation product of the at least one silane derivative of the formula (III) and/or any mixture thereof is/are present in the coating composition in a total amount in the range preferably of from 9%by weight to 81%by weight, further preferably of from 13%by weight to 76%by weight, more preferably of from 19%by weight and most preferably of from 23%by weight to 66%by weight, each based on the total weight of the coating composition. The amounts given before apply with regard to the at least one silane derivative of the formula (III) , with regard to the at least one hydrolysis product of the formula (III) , with regard to the at least one condensation of the formula (III) or with regard to any mixture thereof. The amounts given before apply as well with regard to a mixture of silane derivatives of the formula (III) , with regard to a mixture of hydrolysis products of the at least one silane derivative of the formula (III) , with regard to a mixture of condensation products of the at least one silane derivative of the formula (III) or with regard to any mixture thereof.

The at least one colloidal inorganic oxide, hydroxide, oxide hydrate, fluoride and/or oxyfluoride is/are present in the coating composition in a total amount in the range preferably of from 3%by weight to 60%by weight, further preferably of from 6%by weight to 58%by weight, more preferably of from 9%by weight to 57%by weight and most preferably of from 13%by weight to 55%by weight, each based on the total weight of the coating composition. The amounts given before apply with regard to one type of colloidal inorganic oxide, one type of colloidal inorganic hydroxide, one type of colloidal inorganic oxide hydrate, one type of colloidal inorganic fluoride, one type of colloidal inorganic oxyfluoride and any mixture thereof. The amounts given before apply as well with regard to a mixture of different colloidal inorganic oxides, a mixture of different colloidal inorganic hydroxides, a mixture of different colloidal inorganic oxide hydrates, a mixture of different colloidal inorganic fluorides, a mixture of different colloidal inorganic oxyfluorides or any mixture thereof. The mentioned mixtures may include each different particles sizes or different types of colloidal inorganic oxides, hydroxides, oxide hydrates, fluorides and/or oxyfluorides.

The at least one epoxide compound comprising at least two epoxide groups is present in the coating composition in an amount in the range preferably of from 0.01%by weight to 14%by weight, further preferably of from 0.07%by weight to 11%by weight, more preferably of from 0.1%by weight to 6%by weight and most preferably of from 0.2%by weight to 13%by weight, each based on the total weight of the coating composition. The amount given before apply with regard to one type of epoxide compound as well as with regard to a mixture of different epoxide compounds.

The at least one catalyst system comprising at least one Lewis acid and at least one thermolatent Lewis base-adduct is present in the coating composition in an amount in the range preferably from 0.04%by weight to 4%by weight, further preferably from 0.1%by weight to 3%by weight, more preferably from 0.2%by weight to 2%by weight and most preferably from 0.3%by weight to 1%by weight, each based on the total weight of the coating composition. The weight ratio of the at least one Lewis acid to the at least one thermolatent Lewis base-adduct is preferably in a range from 20: 1 to 2: 1, further preferably from 18: 1 to 1: 2, more preferably from 13: 1 to 1: 1 and most preferably from 6: 1 to 1: 1.

The coating composition may comprise at least one organic solvent and/or water. The components of the coating composition resulting in a hard coating are used in that they add to 100%by weight based on the total weight of the coating composition.

As at least one silane derivate of the formula (III) 3-glycidoxymethyl

trimethoxysilane, 3-glycidoxypropyltrihydroxysilane, 3-glycidoxypropyl-dimethylhydroxysilane, 3-glycidoxypropyl-dimethylethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyl

triethoxysilane, 3-glycidoxypropyldimethoxymethyl

silane, 3-glycidoxypropyldiethoxy-methylsilane and/or 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane for example may be used in the coating composition. Preferably, 3-glycidoxypropyltrimethoxysilane and/or 3-glycidoxy

propyltriethoxysilane is/are used as silane derivative of the formula (III) .

The at least one colloidal inorganic oxide, hydroxide, oxide hydrate may be a metal oxide, metal hydroxide, metal oxide hydrate, where the metal ions of the metal oxide, metal hydroxide, metal oxide hydrate comprise or are the metals of titanium, preferably TiO ₂, of silicon, preferably SiO ₂, of zirconium, preferably ZrO ₂, of tin, preferably SnO ₂, of antimony, preferably Sb ₂O ₃, of aluminum, preferably Al ₂O ₃ or AlO (OH) and/or mixed oxides and/or mixtures thereof. Preferably, the colloidal inorganic oxide, hydroxide, oxide hydrate is a metal oxide, metal hydroxide, metal oxide hydrate, wherein the metal ions of the metal oxide, metal hydroxide, metal oxide hydrate comprise or are metals of titanium, silicon, zirconium or mixtures thereof, further preferably of silicon. Further preferably, the at least one colloidal inorganic oxide, hydroxide, oxide hydrate forms core-shell particles. In such core-shell particles the core comprises preferably a metal oxide, metal hydroxide, metal oxide hydrate, wherein the metal ions of the metal oxide, metal hydroxide, metal oxide hydrate comprise or are metals of titanium, preferably TiO ₂, and/or of zirconium, preferably ZrO ₂ and the shell comprises preferably a metal oxide, metal hydroxide, metal oxide hydrate, wherein the metal ions of the metal oxide, metal hydroxide, metal oxide hydrate comprise or are silicon, preferably SiO ₂. As colloidal inorganic fluoride magnesium fluoride may be used. The at least one colloidal oxide, hydroxide, oxide hydrate, fluoride and/or oxyfluoride has a mean particle size in the range preferably from 3 nm to 70 nm, further preferably from 6 nm to 64 nm, more preferably from 8 nm to 56 nm and most preferably from 9 nm to 52 nm.

As at least one epoxide compound comprising at least two epoxide compounds digylcidyl ether, ethylenglycoldiglycidyl ether, propylenglycoldiglycolglycidyl ether, 1, 4-butandioldiglycidyl ether, 1, 6-hexandioldiglycidyl ether, trimethylolpropantriglycidyl ether, triglycidylglycerin and/or trimethylolethantriglycidylether for example may be used in the coating composition. Preferably, the at least epoxide compound comprises trimethylolpropantriglycidyl ether, butandioldiglycidyl ether and/or 1, 6-hexandioldiglycidyl ether.

As at least one Lewis acid ammonium perchlorate, magnesium perchlorate, sulfonic acids and/or salts of sulfonic acids, such as trifluormethane sulfonic acid and/or salts thereof, for example may be used in the at least one catalyst system.

As at least one Lewis base-adduct a metal complex compound, such as aluminum acetylacetonate, iron acetylacetonate and/or zinc acetylacetonate, for example may be used in the at least one catalyst system.

The use of the coating composition comprising the components (A) to (D) , i.e. at least one silane derivative of the formula (III) , at least one hydrolysis product and/or at least one condensation product thereof, least one colloidal inorganic oxide, hydroxide, oxide hydrate, fluoride or oxyfluoride, at least one epoxide compound and at least one catalyst system, enables the production of at least one hard coating having very good adhesive strength on different uncoated or precoated spectacle lens substrates, having a high hardness, being of high scratch resistance and showing a low tendency to crack formation on different uncoated or precoated spectacle lens substrates.

The coating composition resulting in at least one hard coating is preferably applied to at least one coated or uncoated surface of the spectacle lens substrate by dip coating or by spin coating.

The interfacial energy σ _S of a surface is a measure of the energy expenditure required to alter the surface. It is determined by the intermolecular forces at the surface, which can be decomposed into a dispersive component attributed to the intermolecular van der Waals forces, and a polar component caused by permanent dipole moments of molecules in the hard coating. The interfacial energy σ _S of a surface can therefore be decomposed into a dispersive component

caused by the permanent dipoles of the molecules and a polar component

caused by the van der Waals forces. To the highest possible contribution of the polar component

to the interfacial energy

the at least one hard coating can optionally processed with a plasma or corona surface treatment.

Due to the increase of the surface energy improved surface properties, such as the formation of more hydrophilic reactive groups, and/or improved wetting properties may result. In case the coating of the spectacle lens comprises at least one hard coating and at least one anti-fog coating, preferably at least one hard coating adjacent to at least one anti-fog coating, the at least one anti-fog coating being furthest from the surface of the spectacle lens substrate to be coated, each surface of the at least one hard coating adjacent to the at least one anti-fog coating is preferably surface treated, preferably with a plasma or with a corona discharge.

A good adhesion between the at least one hard coating and the at least one anti-fog coating preferably improves the durability of the at least one anti-fog coating.

In case the spectacle lens substrate is made of an organic hard resin, preferably at least one of the finished surfaces of the spectacle lens substrate is coated with at least one hard coating as described above and at least one primer coating. If the spectacle lens comprises at least one hard coating and at least one primer coating, the at least one primer coating is the layer that is located next, but not necessarily adjacent, to the finished surface of the spectacle lens substrate to be coated. Phrased differently, if at least one of the finished surfaces of the spectacle lens substrate is coated with at least one primer coating and with at least one hard coating, preferably the at least one hard coating is furthest away from the to be coated surface of the spectacle lens substrate. The at least one finished surface of the spectacle lens substrate may be uncoated or precoated.

The average thickness of the at least one primer coating preferably lies in a range of from 300 nm to 1200 nm, further preferably in a range of from 340 nm to 1150 nm, further preferably in a range of from 390 nm to 1120 nm, more preferably in a range of from 440 nm to 1110 nm and most preferably in a range of from 470 nm to 1100 nm. The average thickness is the arithmetic average of the physical thickness of the at least one primer coating measured in at least three positions of the primer coating after application and curing. Preferably, the average thickness of the at least one primer coating is determined by the measurement of the spectral reflectivity and/or the spectral transmissivity.

Preferably, an optical spectrometer, such as one of the devices F20, F10-HC or F10-AR of the company Filmetrics Inc., preferably the device F10-HC, is used to determine the average thickness of the at least one primer coating. Illumination of a spectacle lens comprising a spectacle lens substrate and at least one primer coating with white light causes interference spectra dependent on the physical thickness of the at least one primer coating and the respective refractive index thereof. The path difference corresponds exactly to the multiple of the optical thickness. The average thickness is preferably calculated with Fast Fourier Transformation (FFT) . Alternatively, the average thickness of the at least one primer coating may be determined with at least one scanning electron microscope photograph of a cross-section of the spectacle lens comprising a spectacle lens substrate and at least one primer coating. The thickness of the at least one primer coating is therefore determined in at least three positions and the arithmetic average is formed thereof.

The at least one primer coating may preferably be based on a primer coating composition comprising

i) at least one aqueous aliphatic, cycloaliphatic, aromatic or heteroaromatic polyurethane dispersion, at least one aqueous aliphatic, cycloaliphatic, aromatic or heteroaromatic polyurea dispersion, at least one aqueous aliphatic, cycloaliphatic, aromatic or heteroaromatic polyurethane-polyurea dispersion, at least one aqueous aliphatic, cycloaliphatic, aromatic or heteroaromatic polyester dispersion, preferably at least one aqueous aliphatic polyurethane dispersion or at least one aqueous aliphatic polyester dispersion and more preferably at least one aqueous aliphatic polyurethane dispersion,

ii) at least one solvent,

iii) optionally at least one additive.

The at least one aqueous aliphatic, cycloaliphatic, aromatic or heteroaromatic polyurethane dispersion, at least one aqueous aliphatic, cycloaliphatic, aromatic or heteroaromatic polyurea dispersion, at least one aqueous aliphatic, cycloaliphatic, aromatic or heteroaromatic polyurethane-polyurea dispersion, at least one aqueous aliphatic, cycloaliphatic, aromatic or heteroaromatic polyester dispersion is present in the primer coating composition in a total amount from a range preferably of from 2%by weight to 38%by weight, further preferably of from 4%by weight to 34%by weight, further preferably of from 5%by weight to 28%by weight, more preferably of from 6%by weight to 25%by weight and most preferably of from 7%by weight to 21%by weight, each based on the total weight of the primer coating composition. The total amount comprises the amount of only one of the dispersions mentioned before or a mixture thereof.

The primer coating composition comprises preferably at least one aqueous polyurethane dispersion, wherein the polyurethane comprises a polyester unit as a spacer or the polyurethane dispersion is a polyurethane-polyurea dispersion, characterized by the occurrence of both urethane and urea groups in a macromolecular chain of the polyurethane-polyurea. Such polyurethane dispersions are described for example in WO 94/17116 A1, in particular in WO 94/17116 A1, page 7, lines 11 to 33. The aqueous polyurethane dispersion may be blended with anionically stabilized acrylic emulsions, as described in WO 94/17116 A1, in particular in WO 94/17116 A1, page 7, lines 33 to 35.

The at least one solvent is present in the primer coating composition in an amount from a range preferably of from 68%by weight to 99%by weight, further preferable of from 69%by weight to 98%by weight, more preferably of from 81%by weight to 97%by weight and most preferably of from 89%by weight to 93%by weight, each based on the total weight of the primer coating composition. The amounts mentioned before apply with regard to one type of solvent as well as with regard to a mixture of different solvents.

As at least one solvent preferably at least one organic solvent with a low boiling point of < 100℃ under normal pressure and at least one organic solvent with a middle boiling of 100℃ to 150℃ under normal pressure may be used. As at least one organic solvent with a low boiling point methanol, ethanol, 1-propanol, 2-propanol, tert-butanol, actone, diethyl ether, tert-butylmethyl ether, tetrahydrofuran, chloroform, 1, 2-dichlorethane, methylene chloride, cyclohexane, ethyl acetate, n-hexane, n-heptane and/or methyl ethyl ketone for example may be used. Preferably, methanol, ethanol, 1-propanol and/or 2-propanol are used as at least one solvent with a low boiling point. As at least one organic solvent with a middle boiling point 1-methoxy-2-propanol, 1-butanol, dibutyl ether, 1, 4-dioxan, 3-methyl-1-butanol, 4-hydroxy-4-methyl-2-pentanone, methylisobutylketone and/or toluol for example may be used. Preferably, 1-methoxy-2-propanol and/or 4-hydroxy-4-methyl-2-pentanone is/are used as at least one solvent with a middle boiling point.

The weight ratio of the at least one solvent with a low boiling point to the at least one solvent with a middle boiling point is preferably 1: 1, further preferably 1: 1.4, more preferably 1: 1.5 and most preferably 1: 1.7.

As at least one solvent at least one organic solvent with a low boiling point, at least one solvent with a middle boiling point and water may be used. The weight ratio of the at least one solvent with a low boiling point to the at least one solvent with a middle boiling point to water is preferably 2: 7: 1, further preferably 2.5: 6.5: 1, further preferably 3: 6: 1, more preferably 3: 5: 1 and most preferably 3: 6: 1.

The primer coating composition may comprise optionally at least one additive. The at least one additive may comprise at least one dispersing agent, at least one anti-settling agent, at least one wetting agent, at least one biocide, at least one UV-absorber or mixtures thereof. The at least one additive may be present in the primer coating composition preferably in an amount from a range of from 0.01%by weight to 1.7%by weight, further preferably in an amount from a range of from 0.07%by weight to 1.4%by weight, more preferably in an amount from a range of from 0.09%by weight to 1.1%by weight and most preferably in an amount from a range of from 0.1%by weight to 0.7%by weight, each based on the total weight of the primer coating composition. The amounts mentioned before apply with regard to one type of additive as well as with regard to a mixture of different additives.

The primer coating composition comprising the components i) to iii) , i.e. the at least one dispersion, the at least one solvent and optionally the at least one additive, after application on at least one of the uncoated or precoated surfaces of the spectacle lens substrate, drying and curing results in at least one primer coating.

The at least one primer coating composition resulting in at least one primer coating is preferably applied to at least one precoated or uncoated surface of the optical lens substrate by dip coating or by spin coating.

The components of the primer coating composition material resulting in at least one primer coating are used in that they add to 100%by weight, based on the total weight of the primer coating composition.

Alternatively or additionally to the before mentioned at least one primer coating, the coating of the spectacle lens may comprise at least one primer coating based on a primer composition preferably comprising

ii) at least one solvent,

iii) at least one base, and

iv) optionally at least one additive.

The at least one aqueous aliphatic, cycloaliphatic, aromatic or heteroaromatic polyurethane dispersion, at least one aqueous aliphatic, cycloaliphatic, aromatic or heteroaromatic polyurea dispersion, at least one aqueous aliphatic, cycloaliphatic, aromatic or heteroaromatic polyurethane-polyurea dispersion, at least one aqueous aliphatic, cycloaliphatic, aromatic or heteroaromatic polyester dispersion is present in the primer coating composition in a total amount from a range preferably of from 2%by weight to 31%by weight, further preferably of from 4%by weight to 26%by weight, further preferably of from 5%by weight to 21%by weight, more preferably of from 6%by weight to 20%by weight and most preferably of from 7%by weight to 19%by weight, each based on the total weight of the primer coating composition. The total amount comprises the amount of only one of the dispersions mentioned before or a mixture thereof.

The primer coating composition comprises preferably at least one aqueous polyurethane dispersion, wherein the polyurethane comprises a polyester unit as a spacer or the polyurethane dispersion is a polyurethane-polyurea dispersion, characterized by the occurrence of both urethane and urea groups in a macromolecular chain of the polyurethane-polyurea. Such polyurethane dispersions are described for example in WO 94/17116 A1, in particular in WO 94/17116 A1, page 7, lines 11 to 33. The aqueous polyurethane dispersion may be blended with anionically stabilized acrylic emulsions, as described in WO 94/17116 A1, in particular in WO 94/17116 A1, page 7, lines 33 to 35. According to WO 94/17116 A1, page 7, lines 11 to 33, an aqueous polyurethane dispersion typically is a polyurethane-polyurea, i.e., a polymer characterized by the occurrence of both urethane and urea groups in a macromolecular chain. The aqueous polyurethane dispersion may be blended with anionically stabilized acrylic emulsions as mentioned in WO 94/17166 A1, in particular in WO 94/17116 A1, page 7, lines 33 to 35.

The at least one solvent is present in the primer coating composition in an amount preferably from a range of from 69%by weight to 98%by weight, further preferable of from 73%by weight to 96%by weight, more preferably of from 76%by weight to 94%by weight and most preferably of from 79%by weight to 93%by weight, each based on the total weight of the primer coating composition. The amounts mentioned before apply with regard to one type of solvent as well as with regard to a mixture of different solvents.

As at least one solvent preferably at least one organic solvent with a low boiling point of <100℃ under normal pressure and at least one organic solvent with a middle boiling of 100℃ to 150℃ under normal pressure may be used. As at least one organic solvent with a low boiling point methanol, ethanol, 1-propanol, 2-propanol, tert-butanol, actone, diethyl ether, tert-butylmethyl ether, tetrahydrofuran, chloroform, 1, 2-dichlorethane, methylene chloride, cyclohexane, ethyl acetate, n-hexane, n-heptane and/or methyl ethyl ketone for example may be used. Preferably, methanol, ethanol, 1-propanol and/or 2-propanol are used as at least one solvent with a low boiling point. As at least one organic solvent with a middle boiling point 1-methoxy-2-propanol, 1-butanol, dibutyl ether, 1, 4-dioxan, 3-methyl-1-butanol, 4-hydroxy-4-methyl-2-pentanone, methylisobutylketone and/or toluol for example may be used. Preferably, 1-methoxy-2-propanol and/or 4-hydroxy-4-methyl-2-pentanone is/are used as at least one solvent with a middle boiling point.

Further, additionally to the at least one solvent with a low boiling point and/or to the at least one solvent with a middle boiling point, the primer coating composition may comprise water. The weight ratio of the at least one solvent with a low boiling point to the at least one solvent with a middle boiling point to water is preferably 2: 7: 1, further preferably 2.5: 6.5: 1, further preferably 3: 6: 1, more preferably 3: 5: 1 and most preferably 3: 6: 1.

Further, the primer coating composition comprises at least one base, which confers a buffering effect with respect to the pH value to the at least one primer coating resulting from that primer coating composition. The at least one base preferably retards, more preferably inhibits an acidic component to come into contact with an adjacent layer, preferably an adjacent layer which is located nearer or next or adjacent to the spectacle lens substrate. The primer coating composition comprises the at least one base in an amount in the range of preferably from 0.1%by weight to 3.2%by weight, further preferably from 0.2%by weight to 2.8%by weight, further preferably from 0.3%by weight to 2.4%by weight, more preferably from 0.4%by weight to 1.9%by weight and most preferably from 0.5%by weight to 1.6%by weight, each based on the total weight of the primer coating composition. The amounts given before apply to the use of one type of base as well as to the use of a mixture of different bases. The primer coating composition may comprise as at least one base for example imidazole, 1-methylimidazole, 2-methylimidazole, 4-methylimidazole, 2, 5-dimethylimidazole, 4- hydroxymethylimidazole, pyrazole, 1, 2, 3-triazole, 1, 2, 4-triazole, tetrazole, pentazole, pyrrole, pyrrolidine, pyridine, 4-aminopyridine, 4-methylpyridine, 4-methoxypyridine, 2, 4, 6-trimethylpyridine, piperidine, piperazine, triethylamine, di-isopropyl amine, di-isobutyl amine, caustic soda and/or caustic potash. Preferably, the primer coating composition comprises at least one base selected from the group consisting of 2-methlyimidazole, imidazole, 1-methylimidazole, 4-methylimidazole, 2, 5-dimethylimidazole, triethylamine and caustic soda, more preferably at least one base selected from the group consisting of 2-methylimidazole, 1-methylimidazole, 4-methylimidazole and caustic soda. Most preferably, the primer coating composition comprises at least one base selected from the group consisting of 2-methylimidazole and 1-methylimidazole in an amount of a range from 0.1%by weight to 2%by weight, preferably from 0.3%by weight to 1.5%by weight, each based on the total weight the primer coating composition. The amounts mentioned before apply to the use of a mixture of 2-methylimidazole and 1-methylimidazole as well as to the use of 2-methylimidazole or to the use of 1-methylimidazole.

The primer coating composition may comprise optionally at least one additive. The at least one additive may comprise at least one dispersing agent, at least one anti-settling agent, at least one wetting agent, at least one biocide, at least one UV-absorber or mixtures thereof. The at least one additive may be present in the primer coating composition preferably in an amount of from 0.01%by weight to 1.7%by weight, further preferably in an amount of from 0.07%by weight to 1.4%by weight, more preferably in an amount of from 0.09%by weight to 1.1%by weight and most preferably in an amount of from 0.1%by weight to 0.7%by weight, each based on the total weight of the primer coating composition. The amounts mentioned before apply with regard to one type of additive as well as with regard to a mixture of different additives.

The primer coating composition comprising the components i) to iv) , i.e. the at least one dispersion, the at least one solvent, the at least one base and optionally the at least one additive, after application to at least one precoated or uncoated surface of the spectacle lens substrate, drying and curing results in at least one primer coating.

The primer coating composition resulting in at least one primer coating is preferably applied to at least one precoated or uncoated surface of the spectacle lens substrate by dip coating or by spin coating. The components of the primer coating composition resulting in at least one primer coating are used in that they add to 100%by weight based on the total weight of the primer coating composition.

In one embodiment, the coating of the spectacle lens comprises at least one photochromic coating. Preferably, only the precoated or uncoated finished front surface of the spectacle lens substrate comprises or is coated with at least one photochromic coating. If a spectacle lens comprises at least one hard coating, optionally at least one primer coating and at least one photochromic coating, preferably the at least one photochromic coating is the coating next, but not necessarily adjacent, to the surface of the spectacle lens substrate to be coated and the hard coating is the coating furthest away from said surface. The surface of the spectacle lens substrate preferably is optically finished and may be precoated or uncoated. In case the spectacle lens comprises at least one hard coating, optionally at least one primer coating, at least one photochromic coating and at least one anti-fog-coating, preferably the at least one photochromic coating is the coating next to, but not necessarily adjacent to, the surface of the spectacle lens substrate to be coated, whereas the at least one anti-fog coating is the coating furthest away from said surface. The at least one photochromic coating may for example be based on a photochromic composition described in EP 1 433 814 A1, EP 1 602 479 A1 or EP 1 561 571 A1.

EP 1 433 814 A1, in particular EP 1 433 814 A1, claim 1, discloses a photochromic composition comprising (1) 100 parts by weight of radically polymerizable monomers; (2) 0.01 to 20 parts by weight of an amine compound; and (3) 0.01 to 20 parts by weight of a photochromic compound, the radically polymerizable monomers including a radically polymerizable monomer having a silanol group or a group which forms a silanol group by hydrolysis, and/or a radically polymerizable monomer having an isocyanate group. According to EP 1 433 814 A1 to increase adhesion between the photochromic coating resulting from the photochromic composition described therein and a spectacle lens substrate, a radically polymerizable monomer having a silanol group or a group which forms a silanol group by hydrolysis or a radically polymerizable monomer having an isocyanate group is used. Usable monomers are mentioned in EP 1 433 814 A1, page 3, paragraph [0025] , to page 7, paragraph [0046] . Additionally, according to EP 1 433 814 A1 the photochromic composition may include other radically polymerizable monomers. As other polymerizable monomers, a combination of a radically polymerizable monomer having a homopolymer L-scale Rockwell hardness of at least 60 ( “high-hardness monomer” ) and a radically polymerizable monomer having a homopolymer L-scale Rockwell hardness of 40 or less ( “low-hardness monomer” ) is preferably used to improve the characteristic properties such as solvent resistance, hardness and heat resistance of the resulting photochromic coating or the photochromic properties thereof such as colour development intensity and fading speed. Examples and explanations with respect to the high-hardness monomers and the low-hardness monomers are given in EP 1 433 814 A1, page 7, paragraph [0052] , to page 13, paragraph [0096] . To improve the balance of the characteristic properties such as solvent resistance, hardness and heat resistance or photochromic properties such as colour development intensity and fading speed of the resulting photochromic coating, the amount of a low-hardness monomer is preferably 5 to 70%by weight and the amount of a high-hardness monomer is preferably 5 to 95%by weight based on the total of all the other radically polymerizable monomers excluding the radically polymerizable monomer having a silanol group or a group which forms a silanol group by hydrolysis and the radically polymerizable monomer having an isocyanate group. Further, according to EP 1 433 814 A1, it is particularly preferred that a monomer having at least three radically polymerizable groups should be contained as the high-hardness monomer in an amount of at least 5%by weight based on the total of all other radically polymerizable monomers. Further preferably, according to EP 1 433 814 A1, the radically polymerizable monomers include a radically polymerizable monomer having at least one epoxy group and at least one radically polymerizable group in the molecule besides the mentioned monomers classified by hardness. The durability of a photochromic compound and the adhesion of the photochromic coating can be improved by using the radically polymerizable monomer having at least one epoxy group. Radically polymerizable monomers having at least one epoxy group and at least one radically polymerizable group in the molecule are disclosed in EP 1 433 814 A1, page 13, paragraph [0101] , to page 14, paragraph [0105] . According to EP 1 433 814 A1, the amount of the radically polymerizable monomer having at least one epoxy group and at least one radically polymerizable group in the molecule is preferably 0.01 to 30%by weight, particularly preferably 0.1 to 20%by weight based on the total of all other radically polymerizable monomers. The photochromic composition described in EP 1 433 814 A1 comprises at least one amine compound in an amount of 0.01 to 20 parts by weight based on 100 parts by weight of the total of all the radically polymerizable monomers in addition to the above mentioned radically polymerizable monomers. Examples for the at least one amine compound is given in EP 1 433 814 A1, page 14, paragraph [0108] , to page 15, paragraph [0112] . The photochromic composition disclosed in EP 1 433 814 A1 comprises at least one photochromic compound in an amount of 0.01 to 20 parts by weight, preferably 0.05 to 15 parts by weight and more preferably 0.1 to 10 parts by weight based on 100 parts by weight of the total of all radically polymerizable monomers. Examples for photochromic compounds are given in EP 1 433 814 A1, page 15, paragraph [0114] to page 20, paragraph [0122] . EP 1 602 479 A1, in particular EP 1 602 479 A1, claim 9, discloses a photochromic composition comprising 100 parts by weight of a radically polymerizable monomer, 0.001 to 5 parts by weight of a silicone base or fluorine base surfactant and 0.01 to 20 parts by weight of a photochromic compound. According to EP 1 602 479 A1, the photochromic composition comprises a radically polymerizable monomer having a silanol group or a group which forms a silanol group by hydrolysis, an amine compound and a photochromic compound. The use amount of the radically polymerizable monomer having a silanol group or a group which forms a silanol group by hydrolysis is suitably 0.5 to 20%by weight, particularly 1 to 10%by weight based on the total weight of the whole coating agents. Other radically polymerizable monomers which according to EP 1 602 479 A1 can be used together with the radically polymerizable monomer having a silanol group or a group which forms a silanol group by hydrolysis, such as for example trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, tetramethylolmethane trimethacrylate, tetramethylolmethane triacrylate, trimethylolpropane triethylene glycol triacrylate, pentaerythritol tetramethacrylate, dipentaerythritol hexaacrylate, urethane oligomer tetraacrylate, urethane oligomer hexamethacrylate, urethane oligomer hexaacrylate, polyester oligomer hexaacrylate, diethyleneglycol dimethacrylate, triethyleneglycol dimethacrylate, tetraethyleneglycol dimethacrylate, tripropireneglycol dimethacrylate, bisphenol A dimethacrylate, 2, 2-bis (4-methacryloyloxyethoxydiphenyl) propane, glycidyl methacrylate, 2, 2-bis (4-acryloyloxypolyethylene glycol phenyl) propane having an average molecular weight of 776 or methyl ether polyethylene glycol methacrylate having an average molecular weight of 475. The use amount of the other radically polymerizable monomers is suitably 20 to 90%by weight, particularly 40 to 80%by weight based on the weight of the whole coating agents. The use amount of the amine compound, such as triethanolamine, N-methyldiethanolamine, triisopropanolamine, N, N-dimethylaminoethyl methacrylate or N, N-diethylaminoethyl methacrylate for example, is suitably 0.01 to 15%by weight, particularly 0.1 to 10%by weight based on the weight of the whole coating agents. The use amount of the photochromic compound such as a naphthopyran derivative, a chromene derivative, a spirooxazine derivative, a spiropyran derivative or a flugimide derivative is suitably 0.1 to 30%by weight, particularly 1 to 10%by weight based on the weight of the whole coating agents.

In case the spectacle lens comprises at least one photochromic coating, preferably the front surface of the uncoated or precoated spectacle lens substrate comprising the at least one photochromic coating, the spectacle lens may optionally comprise at least one photochromic primer. Preferably the front surface of the spectacle lens substrate comprises the at least one photochromic primer and the at least one photochromic coating, the photochromic coating being the outermost coating thereof. The at least one photochromic primer may comprise the polyurethane resin layer disclosed in EP 1 602 479 A1, in particular in EP 1 602 479 A1, claim 1, or the primer layer disclosed in WO 03/058300 A1, in particular in WO 03/058300 A1, page 22, line 3 to page 23, line 13.

In one embodiment, the spectacle lens may comprise at least one mirror coating. In case the spectacle lens comprises at least one mirror coating. The at least one mirror coating typically comprises alternating dielectric layers in the manner of a Bragg mirror and/or at least one semitransparent metal layer. The at least one semitransparent metal layer may comprise, for example, an aluminum layer, chromium layer, gold layer and/or silver layer. The layer thickness of the semitransparent metal layer is typically within a range of from 4 nm to 48 nm, more typically within a range of from 8 nm to 41 nm and most typically within a range of from 17 nm to 33 nm. The at least one semitransparent metal layer is typically applied by means of a physical vapor deposition method.

The spectacle lens comprises preferably at least one antireflective coating. The at least one antireflective coating preferably comprises alternating discrete metal oxide, metal hydroxide and/or metal oxide hydrate layers composed of or comprising aluminum, silicon, zirconium, titanium, yttrium, tantalum, neodymium, lanthanum, niobium and/or praseodymium. The at least one antireflective coating preferably comprises at least one layer of a metal oxide, metal hydroxide and/or metal oxide hydrate layer composed of or comprising silicon, which preferably forms the outermost layer of the antireflective coating. Suitable materials for the antireflective coating include metals, non-metals, like silicon or boron, oxides, fluorides, silicides, borides, carbides, nitrides, and sulfides of metals. These substances may be used individually or as a mixture of two or more of these materials. Preferred metal oxides and/or non-metal oxides include SiO, SiO ₂, ZrO ₂, AI ₂O ₃, TiO, TiO ₂, Ti ₂O ₃, Ti ₃O ₄, CrO, Cr ₂O ₃, Y ₂O ₃, Yb ₂O ₃, MgO, Ta ₂O ₅, CeO ₂ and HfO ₂.

The antireflective coating typically comprises a coating stack of at least one layer with a high refractive index (HRI) and of at least one layer with a low refractive index (LRI) . There is no limitation for the number of layers. However, from the perspective of broadband reflection reduction, the layer total number in the antireflective coating is preferably higher than or equal to 3, further preferably higher than or equal to 5, and lower than or equal to 9. Preferably, the HRI layers have a physical thickness ranging from 10 to 120 nm and the LRI layers have a physical thickness ranging from 10 to 100 nm. The at least one antireflective coating preferably has a total layer thickness from a range from 100 nm to 1000 nm, preferably from a range from 110 nm to 800 nm, further preferably from a range from 120 nm to 750 nm, more preferably from a range from 130 nm to 700 nm and most preferably from a range from 140 nm to 500 nm. The at least one antireflective coating may be designed with respect to the desired optical properties thereof preferably by using the software OptiLayer, version 12.37, of company OptiLayer GmbH, 85748 Garching b. München, or the software Essential MacLeod, version 11.00.541, of company Thin Film Center Inc., 2745 E Via Rotunda, Tucson, AZ USA. For designing the at least one antireflective coating, the respective refractive indices of the layer materials preferably are assumed to be wavelength dependent. In case the antireflective coating comprises at least one layer of SiO ₂ and at least one layer of TiO ₂, the designing the antireflective coating preferably is based on a refractive index for TiO ₂ of n= 2.420 at 550 nm and a refractive index for SiO ₂ of n = 1.468 at 550 nm.

The at least one antireflective coating may comprise the layer sequence and the layer thickness indicated in EP 2 437 084 A1, in figures 3 and 5, in each case between the superhydrophobic layer and the hard lacquer layer or the layer sequence and the layer thicknesses disclosed in paragraph [0056] of EP 2 801 846 A1.

In a spectacle lens comprising at least one hard coating and at least one antireflective coating, the at least antireflective coating preferably forms the outermost coating. The antireflective coating is preferably disposed on top of the at least one hard coating on the eye side and/or object side of the spectacle lens.

In one embodiment, the spectacle lens may comprise at least one electrically conductive or semiconductive layer. The at least one electrically conductive or semiconductive layer may comprise, for example, a layer composed of or comprising indium tin oxide ( (In ₂O ₃) _0.9 (SnO ₂) _0.1; ITO) , fluorine tin oxide (SnO ₂: F; FTO) , aluminum zinc oxide (ZnO: Al; AZO) and/or antimony tin oxide (SnO ₂: Sb; ATO) . Preferably, the electrically conductive or semiconductive layer comprises a layer composed of or comprising ITO or composed of or comprising FTO. An electrically conductive or semiconductive layer arranged as the outermost layer of the spectacle lens on the object side or eye side reduces or avoids the static charging of the spectacle lens. This in turn facilitates the cleaning of the spectacle lens. The at least one electrically conductive or semiconductive layer may be one of the layers of the antireflective coating.

Preferably the at least one antireflective coating is manufactured by physical vapor deposition, preferably by means of electron beam evaporation or thermal evaporation in a vacuum chamber.

The spectacle lens comprises at least one anti-fog coating. In case at least one of the surfaces of the spectacle lens substrate is coated with at least one anti-fog coating, the at least one anti-fog coating preferably is the outermost coating. In case at least one of the surfaces of the spectacle lens substrate is coated with at least one anti-fog coating and at least one clean coat layer, the at least one clean coat layer preferably is the outermost coating.

The at least one anti-fog coating preferably is of hydrophilic nature wherein the hydrophilic groups of the at least one anti-fog coating orient towards the outermost interface of the at least one anti-fog coating, i.e. not to the interface of the at least one anti-fog coating that is direct towards the spectacle lens substrate, resulting in an increase of the surface energy thereof. When water vapor comes into contact with that outermost interface, instead of the formation of tiny water droplets, the water vapor is captured by the hydrophilic groups and forms a layer of water being absorbed within the hydrophilic anti-fog coating and no fog will occur.

The at least one anti-fog coating preferably comprises an antifogging resin or surfactant, including highly hydrophilic polymers such as polyvinyl alcohol, (sodium) polyacrylate, or polyurethane comprising hydrophilic groups. For example, there are commercially available antifog resins UVAF, AFC-GW, AFC-133P12G, AFC-SW6M and AFC-G*NK from Gelwell Biotech Corp. and Visgard Premium, Visgard Premium SE, Visgard Premium Plus and Visgard Elite from FSI Coating Technologies, Inc.

The layer thickness of the al least one anti-fog coating is not subject in principle to any special constraint. The layer thickness of the at least one anti-fog coating each lies preferably in a range of from 1 μm to 20 μm, further preferably in a range of from 2 μm to 17 μm, more preferably in a range of from 3 μm to 15 μm, most preferably in a range of from 4 μm to 12 μm and particularly preferably in a range of from 5 μm to 10 μm. The thickness of the at least one anti-fog coating preferably is the average thickness, preferably determined by at least one scanning electron microscope photograph of a cross-section of the spectacle lens comprising at least a spectacle lens substrate and at least one anti-fog coating. In the at least one scanning electron microscope photograph, the physical thickness of the at least one anti-fog coating is determined in at least three positions and the arithmetic average is formed thereof.

The at least one anti-fog coating is preferably applied by means of spin coating process.

The spectacle lens comprises at least one clean coat layer. The at least one clean coat layer is preferably the outermost coating. In case the spectacle lens comprises at least one clean coat layer adjacent to at the least one anti-fog coating, the at least one clean coat layer preferably being the outermost layer thereof. The at least one clean coat layer may have oleophobic or hydrophobic properties, as disclosed for example in EP 1 392 613 A1, wherein water forms a contact angle of more than 90°, preferably of more than 100° and particularly of more than 110°. The at least one clean coat layer may comprise for example at least one fluoro organic layer covalently bonding to the underneath adjacent layer as disclosed in DE 198 48 591 A1, claim 1, or at least one layer based on perfluoropolyethers. The at least one clean coat layer is preferably based on at least one hydrophobic coating material comprising silanol-functionalized perfluoropolyethers. Those materials undergo a chemical bonding with free surface hydroxyl groups allowing the hydrophobic chains to smoothly distribute across the surface forming a smooth and slippery coating layer. Further, the at least one clean coat layer is preferably based on at least one silane having at least one fluorine-containing group, which exhibits preferably more than 20 carbon atoms. Per-or polyfluoroalkyl compounds (PFAS) with silane functionality that comprise at least one - (CF ₂) _x-unit with x≥1 are commonly used, to be suitable for vacuum deposition process, these material are commonly present in the shape of pills, commercially available products includes Duralon-series from COTEC GmbH, KY-series from Shin-Etsu Chemical Co., Ltd.

The at least one clean coat layer is preferably of hydrophobic nature ensuring an easy to clean surface to a spectacle lens. Thus, typical contaminations on the surface of a spectacle lens could be easily removed by liquid droplets, preferably water droplets, just rolling off or rolling of in combination with wiping.

The at least one clean coat layer is preferably manufactured by physical vapor deposition.

In case the at least one clean coat layer is not adjacent to the at least one anti-fog coating, the at least one clean coat layer preferably being the outermost coating, the layer thickness of the at least one clean coat layer is not subject in principle to any special constraint. In this case, the thickness of the at least one clean coat layer each lies preferably in a range of from 1 nm to 30 nm, further preferably in a range of from 2 nm to 25 nm, more preferably in a range of from 3 nm to 20 nm, most preferably in a range of from 4 nm to 17 nm and particularly preferably in a range of from 5 nm to 15 nm. The thickness of the at least one clean coat layer preferably is the average thickness, preferably determined by at least one scanning electron microscope photograph of a cross-section of the spectacle lens comprising at least a spectacle lens substrate and at least one clean coat layer. In the at least one scanning electron microscope photograph, the physical thickness of the at least one clean coat layer is determined in at least three positions and the arithmetic average is formed thereof.

In case the at least one clean coat layer is adjacent to the at least on anti-fog coating, the at least one clean coating layer preferably being the outermost coating, the layer thickness of the at least one clean coat layer is preferably balanced not to impair the antifogging effect of the at least one anti-fog coating, e.g. if the layer thickness of the at least one clean coat layer is too high, and not to degrade the functionality of the at least one clean coating layer with respect to its performance of water repelling and antifouling, e.g. if the layer thickness of the at least one clean coat layer is too low. Therefore, in case at least one clean coat layer is adjacent to at least one anti-fog coating, the layer thickness of the at least one clean coat layer each lies preferably in a range of from 1 nm to 20 nm, further preferably in a range of from 1.0 nm to 17 nm, more preferably in a range of from 1.0 nm to 15 nm, most preferably in a range of from 1.0 nm to 13 nm and particularly preferably in a range of from 1 nm to 5 nm.

Preferably, to remain the hydrophobic surface of the at least one clean coat layer while not to significantly reducing the antifogging effect of the at least one anti-fog coating, the average thickness of the at least one clean coat layer may be adapted to have a small water contact angle. Dependent on the composition of the at least one clean coat layer, the thickness of the at least one clean coat layer may need to be reduced for reducing or adapting the water contact angle. Preferably the water contact angle of the at least one clean coat layer lies in a range of from 90° to 105°, more preferably in a range of from 95° to 100°. The water contact angle preferably is determined by means of an OCA20 contact angle meter from Dataphysics using deionized water with a droplet size of 1 μL as liquid. Alternatively or additionally to the low thickness of the at least one clean coat layer, a deposition mask or a shadow mask may be used in the vacuum deposition process for a plasma treatment via ion beam assistance with the chamber purged with Ar or O ₂ gas on the at least one clean coat layer. The surface of the at least one clean coat layer where it is not protected or shielded by the deposition or shadow mask, the hydrophobic material of the at least one clean coat layer may be removed by the plasma treatment and a hybrid surface is created. Alternatively, the surface of the at least one anti-fog coating may be protected or shielded by the deposition or shadow mask and only the not masked parts of the surface of the at least one anti-fog coating are coated with the at least one clean coat layer. The average thickness of the at least one clean coat layer applied with the deposition or shadow mask preferably lies in a range from 1 nm to 50 nm, further preferably from 1 nm to 30 nm, more preferably from 1 nm to 20 nm, and particularly preferably from 1 nm to 10 nm. The average thickness of the at least one clean coat layer applied with the deposition or shadow mask is preferably determined analogously to the thickness of the at least one clean coat layer described above. The deposition or shadow mask preferably is set as the same dimension as the spectacle lens but having many holes. To not to deteriorate the surface slippery the parameters of the holes are preferred to have the diameter ranging from 0.1 to 1 mm, distance of each holes ranging from 1 to 2 mm. Comparing to the wet etching process, shadow mask methodology is versatile because it allows for a wide range of materials to be deposited via a simpler process. The mask can be reused for many depositions by following a simple mask cleaning procedure.

In case the at least one clean coat composition is based on a hydrophobic coating material comprising perfluorinated hydrophobic chains and even though these perfluorinated hydrophobic chains are homogeneously distributed across a surface they still allow water to migrate through. The perfluorinated chains have no significant chemical interaction with themselves due to their inert chemistry offering diffusion channels as shown by the permeability coefficients of common polymers in table 2 of P.M. Bhada, “How Weld Hose Materials Affect Shielding Gas Quality” , Welding Journal, July 1999, pp. 35-40.

In case the coating of the spectacle lens comprises at least one clean coat layer adjacent to at least one anti-fog layer, the at least one clean coat layer preferably being the outermost layer, the hydrophobicity of the at least one clean coat layer may be achieved by at least one - (CF ₂) _x-unit with x≥1. Preferably on a hydrophilic surface, further preferably on the outermost surface of at least one anti-fog coating, molecular chains comprising at least one - (CF ₂) _x-unit with (x≥1) thermal dynamically tend to expand and may results in a networked morphology that protects the surface of the spectacle lens from water or oil-based stains and dirt. But even though those molecular chains are homogeneously distributed across the surface of the at least one anti-fog coating they still allow water to migrate through to the surface of the anti-fog coating. However, it has been found that in case the anti-fog coating underneath the at least one clean coat layer, i.e. the anti-fog coating in direction to the surface of the spectacle lens substrate, is able to absorb water, condensed water droplets from air or breath that may cause fog on at least one surface of the spectacle lens, even in the presence of the at least one clean coating, are usually small enough to be quickly absorbed by the at least one anti-fog coating. Due to that quick absorption the water droplets have no chance to grow to larger size.

Therefore, no fog on the spectacle lens surface visually appears.

A further advantage of the co-existence of at least one anti-fog coating and at least one clean coat layer, the at least one anti-fog coating being adjacent to the at least one clean coat layer, further preferably the at least one clean coat layer being the outermost layer, is that the resistance of the spectacle lens, especially the anti-fog coating, to scratches and abrasion is improved. Due to that co-existence the preferably hydrophilic surface of the at least one anti-fog coating has been converted into a preferably hydrophilic and slippery surface which preferably eases the cleaning and wiping of the spectacle lens. Further preferably, the durability and the long-lasting functionality of the at least one anti-fog coating is enhanced. With the careful controlled layer thickness, preferably in a range of from 1 nm to 5 nm, by the oscillating crystal (state-of the art PVD process control technology) and preferably with 5 to 50 sccm O ₂ or Ar in vacuum deposition process (precise flow meter) the antifogging performance can be kept constant.

Further preferably, the desired properties of a spectacle lens, for example resulting from at least one photochromic coating or at least one antireflective coating are not impaired by the described co- existence of at least one anti-fog coating and at least one clean coat layer. The at least one anti-fog coating and the at least one clean coat layer may be comprised in the coating of a corrective lens, aplano lens, i.e. according to section 3.6.3 of DIN EN ISO 13666: 2019-12 a lens with nominally zero dioptric power, or a shield. The spectacle lenses or the shields may comprise an antireflective coating.

In contrast to IN 201721011814 A wherein the order of the coating sequence is different, in IN 201721011814 A the anti-fog layer being the outermost coating, the co-existence of at least one anti-fog layer and at least one clean coat layer, the coating sequence being the reverse order, i.e. the at least one clean coat layer being the outermost layer, additional protection of the at least one anti-fog layer by the at least one clean coat layer is provided. In IN 201721011814 A the surface contact angle is very high with 109°. At this contact angle, even though there was no visible fogging observed, instead of the formation of tiny water droplets, large sized droplets are formed. This causes visually perceived heavy optical distortion that is much worse than the pure antifogging surface. Oppositely, if the at least one hydrophobic clean coat layer is the outer layer, because of the presence of the hydrophilic anti-fog layer underneath, the water contact angle, as measured in the present invention, is smaller than 100°, and further decreases with bigger droplet size in contact angle measurement. This will ensure a better antifogging performance.

A coating being adjacent to another coating or layer is a coating that is, preferably as a discrete layer, in direct contact with another coating or layer, preferably being a discrete layer as well. Coatings being adjacent include coatings which are covering the whole surface to be coated as well as coating which are covering the surface to be coated only partially.

Summarizing, the following embodiments are particularly preferred within the scope of the present invention:

Embodiment 1: A spectacle lens comprising at least one spectacle lens substrate and at least one coating, wherein the at least one coating comprises at least one anti-fog coating and at least one clean coat layer, each clean coat layer being the outermost layer.

Embodiment 2: A spectacle lens comprising at least one spectacle lens substrate and at least one coating, wherein the at least one coating comprises at least one anti-fog coating and at least one clean coat layer, each clean coat layer being the outermost layer and wherein the spectacle lens comprises from eye to object:

At least one clean coat layer /at least one anti-fog layer /at least one hard coating //back surface of spectacle lens substrate /front surface of spectacle lens substrate //at least one hard coating /at least one antireflective coating /at least one clean coat layer.

Embodiment 3: A spectacle lens comprising at least one spectacle lens substrate and at least one coating, wherein the at least one coating comprises at least one anti-fog coating and at least one clean coat layer, each clean coat layer being the outermost layer and wherein the spectacle lens comprises from eye to object:

At least one clean coat layer /at least one antireflective coating /at least one hard coating //back surface of spectacle lens substrate /front surface of spectacle lens substrate //at least one hard coating /at least one anti-fog coating /at least one clean coat layer.

Embodiment 4: A spectacle lens comprising at least one spectacle lens substrate and at least one coating, wherein the at least one coating comprises at least one anti-fog coating and at least one clean coat layer, each clean coat layer being the outermost layer and wherein the spectacle lens comprises from eye to object:

At least one clean coat layer /at least one anti-fog layer //back surface of spectacle lens substrate /front surface of spectacle lens substrate //at least one hard coating /at least one antireflective coating /at least one clean coat layer.

Embodiment 5: A spectacle lens comprising at least one spectacle lens substrate and at least one coating, wherein the at least one coating comprises at least one anti-fog coating and at least one clean coat layer, each clean coat layer being the outermost layer and wherein the spectacle lens comprises from eye to object:

At least one clean coat layer /at least one antireflective coating /at least one hard coating //back surface of spectacle lens substrate /front surface of spectacle lens substrate //at least one anti-fog coating /at least one clean coat layer.

Embodiment 6: A spectacle lens comprising at least one spectacle lens substrate and at least one coating, wherein the at least one coating comprises at least one anti-fog coating and at least one clean coat layer, each clean coat layer being the outermost layer and wherein the spectacle lens comprises from eye to object:

At least one clean coat layer /at least one anti-fog coating /at least one hard coating //back surface of the spectacle lens substrate /front surface of the spectacle lens substrate //at least one hard coating /at least one anti-fog coating /at least one clean coating.

Embodiment 7: A spectacle lens comprising at least one spectacle lens substrate and at least one coating, wherein the at least one coating comprises at least one anti-fog coating and at least one clean coat layer, each clean coat layer being the outermost layer and wherein the spectacle lens comprises from eye to object:

At least one clean coat layer /at least one anti-fog coating //back surface of the spectacle lens substrate /front surface of the spectacle lens substrate //at least one hard coating /at least one anti-fog coating /at least one clean coating.

Embodiment 8: A spectacle lens comprising at least one spectacle lens substrate and at least one coating, wherein the at least one coating comprises at least one anti-fog coating and at least one clean coat layer, each clean coat layer being the outermost layer and wherein the spectacle lens comprises from eye to object:

At least one clean coat layer /at least one anti-fog coating /at least one hard coating //back surface of the spectacle lens substrate /front surface of the spectacle lens substrate //at least one anti-fog coating /at least one clean coating.

Embodiment 9: A spectacle lens comprising at least one spectacle lens substrate and at least one coating, wherein the at least one coating comprises at least one anti-fog coating and at least one clean coat layer, each clean coat layer being the outermost layer and wherein the spectacle lens comprises from eye to object:

At least one clean coat layer /at least one anti-fog coating //back surface of the spectacle lens substrate /front surface of the spectacle lens substrate //at least one anti-fog coating /at least one clean coating.

Embodiment 10: A spectacle lens comprising at least one spectacle lens substrate and at least one coating, wherein the at least one coating comprising at least one anti-fog coating and at least one clean coat layer, the at least one clean coat layer being the outermost layer thereof, the at least one coating further comprising at least one antibacterial and/or antiviral coating.

Embodiment 11: The spectacle lens according to embodiment 10, wherein the at least one antibacterial and/or antiviral coating comprises at least one biocidal inorganic component and at least one binding inorganic component.

Embodiment 12: The spectacle lens according to any one of embodiment 10 or embodiment 11, wherein the at least one biocidal inorganic component is selected from the group consisting of at least one metal, at least one metal oxide, at least one metal hydroxide, at least one metal oxide hydrate and at least one metal sulfide each composed of or each comprising preferably Ag, AgO, Ag ₂O, Ag ₂S; copper, preferably Cu, Cu ₂O; titanium, preferably TiO, TiO ₂, Ti ₂O ₃, Ti ₃O ₄; zinc, preferably ZnO; and/or iron, preferably FeO, Fe ₂O ₃.

Embodiment 13: The spectacle lens according to any one of embodiments 10 to 12, wherein the at least one binding inorganic component is selected from the group consisting of at least one inorganic metal oxide, at least one metal hydroxide, at least one metal oxide hydrate and at least one metal sulfide each composed of or each comprising silicon, preferably SiO ₂; titanium, preferably TiO, TiO ₂, Ti ₂O ₃, Ti ₃O ₄; aluminum, preferably Al ₂O ₃; and/or zirconium, preferably ZrO ₂.

Embodiment 14: The spectacle according to any one of embodiments 10 to 13, wherein the spectacle lens substrate comprises the at least one antibacterial and/or antiviral coating on one surface of the spectacle lens substrate and at least one anti-fog coating and at least one clean coat layer on the opposite surface thereof, preferably the at least one antibacterial and/or antiviral coating on the front surface of the spectacle lens substrate and the and at least one anti-fog coating and at least one clean coat layer on the back surface of the spectacle lens substrate.

Embodiment 15: A spectacle lens comprising a lens sliding angle within a range of from >6° to <41°, preferably of from >20° to <40°, further preferably of from >25° to ≤39°, the spectacle lens preferably comprising at least one anti-fog coating and at least one clean coat layer, the at least one clean coat layer preferably being the outermost layer thereof.

Embodiment 16: A spectacle lens comprising at least one spectacle lens substrate and at least one coating, wherein the at least one coating comprising at least one anti-fog coating and at least one clean coat layer, the at least one clean coat layer being the outermost layer thereof, wherein spectacle lens exhibits antifogging properties after passing≥2000 strokes of hand wiping by a microfiber cloth with water, the antifogging properties preferably assessed by holding the spectacle lens in a distance of 10 cm over a steam bath with 90℃ hot water for 10 seconds and judging the readability of a printed text through the spectacle lens, the printed text preferably being readable.

Embodiment 17: A spectacle lens comprising at least one spectacle lens substrate and at least one coating, wherein the at least one coating comprises at least one anti-fog coating and at least one clean coat layer, each clean coat layer being the outermost layer and wherein the spectacle lens comprises from eye to object:

At least one clean coat layer /at least one anti-fog coating /at least one hard coating //back surface of the spectacle lens substrate /front surface of the spectacle lens substrate //optionally at least one photochromic coating/optionally at least one primer coating/at least one hard coating /at least one anti-fog coating /at least one clean coating.

Without limiting the scope of the invention, the following examples are given:

I Spectacle lens according to the examples and comparative example

Comparative example 1

A finished lens comprising a factory hardcoating (VISION EASE Tegra Polycarbonate Aspheric FSV) was firstly ultrasonically cleaned and dip coated in the antifog resin Visgard Elite from FSI Inc.

Comparative example 2

A finished lens comprising a factory hardcoating (VISION EASE Tegra Polycarbonate Aspheric FSV) was firstly ultrasonically cleaned and vacuum deposited with a five layers antireflective coating that the material of each layer is SiO ₂, CrO ₂, SiO ₂, CrO ₂, SiO ₂ respectively. The layer thickness were 30nm, 30nm, 20nm, 60nm and 90nm. Afterwards, the lens was further coated a hydrophobic clean coat layer (Cotec Duralon 300+, Company: Cotec GmbH) with a thickness of 5 nm,

Example 1

A finished lens comprising a factory hardcoating (VISION EASE Tegra Polycarbonate Aspheric FSV) was firstly ultrasonically cleaned and dip coated in the antifog resin Visgard Elite from FSI Inc. The coated lens was further deposited with 1 nm of the hydrophobic material Cotec 300+ from COTEC GmbH as clean coat layer.

Example 2

A finished lens comprising a factory hardcoating (VISION EASE Tegra Polycarbonate Aspheric FSV) was firstly ultrasonically cleaned and dip coated in the antifog resin Visgard Elite from FSI Inc. The coated lens was further deposited with 2 nm of the hydrophobic clean coat layer Cotec 300+ from COTEC GmbH.

Example 3

A finished lens comprising a factory hardcoating (VISION EASE Tegra Polycarbonate Aspheric FSV) was firstly ultrasonically cleaned and dip coated in the antifog resin Visgard Elite from FSI Inc. The lens was further deposited with 5 nm of hydrophobic clean coat layer Cotec 300+ from COTEC GmbH.

Example 4

A finished lens comprising a factory hardcoating (VISION EASE Tegra Polycarbonate Aspheric FSV) was firstly ultrasonically cleaned and dip coated in the antifog resin Visgard Elite from FSI Inc. The lens was further deposited with 10 nm of hydrophobic clean coat layer Cotec 300+ from COTEC GmbH.

II Characterisation of the spectacle lenses of the examples and the comparative example

IIa Determination of contact angle

The water contact angle of the spectacle lenses according to the examples and comparative was measured with an OCA20 contact angle meter from Dataphysics; deionized water was used as liquid. Droplet size 1 and 10μL. The results are given in table 2 below.

IIb Determination of Bayer ratio

For the determination of the scratch resistance of the coating of the spectacle lenses according the examples and comparative example, the Bayer ratio was determined according to the COLTS operating procedure. A small pan loaded with a spectacle lens according to the examples or comparative examples as well as loaded with an uncoated diethylene glycol bisallylcarbonate spectacle lens (CR-39 lens) is shaken back and forth a distance of 4 inches, at 150 cycles per minute for 4 minutes. Holes that have been placed across the center section of the pan allow the spectacle lenses to protrude up through the center of each hole, resulting in abrasion in the presence of Kryptonite B as abrasion media. The spectacle lens according to the examples or comparative examples and the CR-39 lens had a hazemeter measurement completed prior to abrasion and another following abrasion. The resulting haze gain of the spectacle lens according to the examples and comparative examples is divided into the resulting haze of the CR-39 lens to establish a ratio of how many more times abrasion resistant the spectacle lens according to the examples or comparative examples is compared to the CR-39 lens. The Bayer ratio R is defined as

with Dstd being the final %haze value of the CR-39 lens minus the initial %haze value of the CR-39 lens and Dtest being the final %haze value of the spectacle lens according to the examples or comparative examples minus the initial %haze value of the spectacle lens according to the examples and comparative examples. The haze-gard plus, company BYK-Gardner GmbH, was used for haze measurement. The higher the Bayer ratio of a coating, the more scratch resistant is the coating. A coating having a Bayer ratio of 1 means that the coating has the same scratch resistance as the CR-39 lens. The Bayer ratios of the spectacle lenses according to the examples and comparative example are given in table 2 below.

IIc Determination of lens sliding angle

The lens sliding angle is a measure of the friction of a lens surface to another desired surface. It is measured by putting the convex side of spectacle lenses of the examples and comparative example on a tilted plate that covered with a standard A4 size printing paper, the tilting angle of the plate is adjustable. The sliding angle is the measured tilting angle when the lens starts to slide down. The results are given in table 2 below.

IId Testing of machine wiping

Machine wiping testing is undertaken with a self-made abrasion tester. Thereby the surface of the spectacle lenses according to the examples and comparative example is rubbed for a specific number of strokes (one stroke = one back and one forth action) with a microfiber cloth under 200 g mass loading. The microfiber cloth was kept wet through the test period.

After every 50 strokes the spectacle lenses are visually inspected by three levels:

1) Passed: if the rating = 1 in hot fog test

3) Failed: if the rating ≥3 in hot fog test

The respective results are given in table 2 below.

IIe Testing of manual wiping

The manual wiping is undertaken with the spectacle lenses according to the examples and comparative example are hand wiped by a microfiber cloth with water. After every 500 strokes the spectacle lenses are inspected by two levels:

1) Passed: if the rating ≤2 in hot fog test

2) Failed: if the rating ≥3 in hot fog test

The results are given in table 2 below.

IIf Hot fog test

The anti-fog properties are assessed by holding the spectacle lenses according to the examples and comparative example in a distance of 10 cm over a steam bath with 90℃ hot water for 10 seconds. Assessment of the anti-fog properties:

The anti-fog properties are judged by reading a printed text through the spectacle lenses. The rating is from 1 to 6, with 1 being the best and 6 the worst. With the rating 1 the printed text is easily readable, with the rating 3 the printed text is still readable and with the rating 6 the printed text not readable any more.

Pass/Fail criteria:

1) Passed: if the rating ≤2 in hot fog test

2) Failed: if the rating ≥3 in hot fog test

IIg Adhesion

The adhesion of the coating to the spectacle lens was evaluated by the cross-cut test. This test applies and removes pressure sensitive tape (3M Scotch 600) over the two cuts made in the coating and into the substrate. The cuts are made by a blade tool with 6 blades parallelly installed, 25 grids of size 1mm x 1mm is formed by cutting perpendicularly. The ranking is made based on the percentage of the delaminated area to the grids area according to BYK Gardner catalogue “QC solutions for coatings and plastics” , 2018, page 158. If the delaminated area is more than 5%, the adhesion is considered as fail. The results are shown in table 2 below.

Table 2:

Claims

Spectacle lens comprising at least one spectacle lens substrate and at least one coating,

characterized in that

the spectacle comprises at least one anti-fog coating and at least one clean coating, the at least one clean coating being the outermost layer thereof.
Spectacle lens according to claim 1,

characterized in that

the at least one anti-fog coating and the at least one clean coating are directly adjacent to each other.
Spectacle lens according to any of the preceding claims,

characterized in that

the thickness of the at least one anti-fog coating lies in a range of from 1 μm to 20 μm.
Spectacle lens according to any of the preceding claims,

characterized in that

the at least one clean coat layer cover the at least one anti-fog layer completely or partially.
Spectacle lens according to any of the preceding claims,

characterized in that

the thickness of the at least one clean coat layer each lies in a range of from 1 nm to 30 nm.
Spectacle lens according to any of the preceding claims,

characterized in that

the water contact angle of the at least one clean coat layer lies in a range of from 90° to 105°.
Spectacle lens according to any of the preceding claims,

characterized in that

the combination of the at least one anti-fog coating and the at least one clean coat layer confers at least one slippery surface to the at least one spectacle lens.
Spectacle lens according to any of the preceding claims,

characterized in that

the combination of the at least one anti-fog coating and the at least one clean coat layer enhances the durability of the at least one anti-fog coating.
Spectacle lens according to any of the preceding claims,

characterized in that

the lens sliding angle of the spectacle lens lies in a range of from >6° to <41°.
Spectacle lens according to any of the preceding claims,

characterized in that

the spectacle lens exhibits antifogging properties after passing≥ 2000 strokes of hand wiping by a microfiber cloth with water.
A spectacle lens according to any of the preceding claims,

characterized in that

the spectacle lens comprises from eye to object:

At least one clean coat layer /at least one anti-fog coating /at least one hard coating//back surface of the spectacle lens substrate /front surface of the spectacle lens substrate //at least one hard coating /at least one anti-fog coating /at least one clean coating.
The spectacle lens according to any of the preceding claims,

characterized in that the coating composition configured to produce the at least one hard coating preferably comprises

A) a) at least one silane derivative of the formula (I) Si (OR ¹) (OR ²) (OR ³) (OR ⁴) , wherein R ¹, R ², R ³ and R ⁴, which may be the same or different, are selected from an alkyl, an acyl, an alkyleneacyl, a cycloalkyl, an aryl or an alkylenearyl group, each of which may optionally be substituted, and/or

b) at least one hydrolysis product of the at least one silane derivative of the formula (I) , and/or

c) at least one condensation product of the at least one silane derivative of the formula (I) , and/or

d) any mixture of the components a) to c) thereof;

B) a) at least one silane derivative of the formula (II) R ⁶R ⁷ _3-nSi (OR ⁵) _n, in which R ⁵ is selected from an alkyl, an acyl, an alkyleneacyl, a cycloalkyl, an aryl or an alkylenearyl group, each of which may optionally be substituted, R ⁶ is an organic radical containing an epoxide group, R ⁷ is selected from an alkyl, a cycloalkyl, an aryl or an alkylenearyl group, each of which may optionally be substituted, n is 2 or 3; and/or

b) at least one hydrolysis product of the at least one silane derivative of the formula (II) , and/or

c) at least one condensation product of the at least one silane derivative of the formula (II) , and/or

d) any mixture of the components a) to c) thereof;

C) at least one colloidal inorganic oxide, hydroxide, oxide hydrate, fluoride and/or oxyfluoride;

D) at least one epoxide compound having at least two epoxide groups; and

E) at least one catalyst system comprising at least one Lewis acid and at least one thermolatent Lewis acid-base adduct.
Method for manufacturing a spectacle lens comprising at least one spectacle lens substrate and

at least one coating,

characterized in that

the spectacle comprises at least one anti-fog coating and at least one clean coating, the at least one clean coating being the outermost layer thereof and the method comprises

a) providing at least one spectacle lens substrate,

b) applying at least one anti-fog coating on at least one surface of the spectacle lens substrate, and

c) depositing at least one clean coat layer.
Method for manufacturing according to claim 13,

characterized in that

the at least one anti-fog coating is applied by dip coating and the at least one clean coat layer is deposited by at least one of the methods selected from the group consisting of i) optionally ion-beam assisted co-evaporation; ii) ion-beam co-sputtering; iii) cathode co-sputtering and iv) plasma-assisted chemical vapor co-deposition.