EP1815276A1

EP1815276A1 - Improving the adhesion of hydrophobic coatings on eyeglass lenses

Info

Publication number: EP1815276A1
Application number: EP05796611A
Authority: EP
Inventors: Bärbel GÖTZ; Cecile Stolz; Gerd-Peter Scherg; Silvia Tomalka
Original assignee: Rodenstock GmbH
Current assignee: Rodenstock GmbH
Priority date: 2004-11-25
Filing date: 2005-10-13
Publication date: 2007-08-08
Also published as: JP2008522202A; US20080038483A1; WO2006056274A1; DE102004056965A1

Abstract

The invention relates to a method for producing an eyeglass lens that is provided with improved adhesion between an antireflective coating or mirror coating that is applied to the eyeglass lens and comprises a single-layer or multilayer structure and a hydrophobic and/or oleophobic coating. Said method comprises the following steps: an eyeglass lens is provided; a hard layer is optionally applied to the surface of the eyeglass lens; an antireflective coating or mirror coating encompassing one or several antireflective layers or mirror layers is applied; a plasma treatment is performed after applying the outermost antireflective layer; and a hydrophobic and/or oleophobic coating is applied.

Description

Improvement of the adhesion of hydrophobic coatings

lenses

The present invention relates to a process for the production of a spectacle lens with improved adhesion between an anti-reflection or anti-reflection coating applied to the spectacle lens, which has a single-layer or multilayer structure, and a hydrophobic and / or oleophobic coating.

The prior art discloses spectacle lenses with an antireflection coating and a hydrophobic coating applied thereto. Such coating systems, however, have the problem that the lifetime of a hydrophobic coating is often insufficient, since the adhesion between the antireflection coating and the hydrophobic coating is insufficient.

Thus, the present invention is based on the technical object of providing a method for producing a spectacle lens with improved adhesion between an antireflection or mirror coating applied to the spectacle lens and a hydrophobic and / or oleophobic coating (also known as "TopCoaf"). Coating).

This object is achieved by providing the embodiments characterized in the claims.

In particular, according to the present invention, a process is provided for the production of a spectacle lens with improved adhesion between an antireflection or mirror coating applied to the spectacle lens, which has a monolayer or multilayer structure, and a hydrophobic and / or oleophobic coating the steps:

(a) providing an (uncoated) spectacle lens,

(b) optionally applying a hard layer to the surface of the glass lens, (c) applying an antireflective or mirror coating comprising one or more antireflective or mirroring layers;

(d) performing a plasma treatment after applying the last or outermost antireflective layer, and (e) applying a hydrophobic and / or oleophobic coating.

As spectacle lens, a plastic glass, for example of polythiourethane, polyepisulfide, PMMA, polycarbonate, polyacrylate or polydiethylene glycol bisallyl carbonate (CR 39 ^® ) or any mixtures of two or more of such materials, or a mineral glass can be used.

The hard layer optionally to be applied in the process according to the invention is not subject to any particular restriction. The hard layer may have a single-layer or multi-layer structure. Various materials and methods can be used to produce the hardcoat. A person skilled in the art is able to select suitable materials for the hard layer and the thickness of the hard layer in a suitable manner. Usually, the hard layer is applied in the form of a hard lacquer or an inorganic material, in particular quartz-based, by means of plasma-assisted vapor deposition techniques or CVD methods. The application of a hardcoat is generally carried out by means of conventional methods, such as a dipping method, a spray method or a spincoat method. However, it is preferred to use a hard layer based on an acrylic polymer, a urethane polymer, a melamine polymer, a silicone resin or an inorganic material, in particular based on quartz. According to a particularly preferred embodiment, a silicone resin is applied as a hard layer to the surface of the spectacle lens, for example starting from siloxanes.

Suitable silicone resins have a composition comprising one or more of the following components:

(1) organosiloxane compounds with or without functional groups, such as glycidoxypropyltrimethoxysilane, (2) co-reactants for functional groups of functional organosilanes, such as organic epoxides, amines, organic acids, organic anhydrides, imines, amides, ketamines, acrylic compounds and isocyanates,

(3) colloidal silica, sols, and / or metal and non-metal oxide sols which preferably have an average particle diameter of about

1 to about 100 nm and more preferably about 5 nm to about 40 nm,

(4) catalysts for silanol condensation, such as dibutyltin dilaurate, zinc naphthenate, aluminum acetylacetonate, zirconium octoate, lead 2-ethylhexoate, aluminum alkoxides and aluminum alkoxide organosilicone derivatives and titanium acetylacetonate,

(5) Catalysts for co-reactants, such as epoxy catalysts and free-radical type catalysts,

(6) solvents such as water, alcohols and ketones; (7) surfactants such as fluorinated surfactants or polydimethylsiloxane-type surfactants;

(8) other additives, such as fillers. Such materials are described, for example, in EP 0 871 907 B1, cf. Sections [0023] to [0026].

The layer thickness of the hard layer is fundamentally not subject to any particular restriction. However, it is preferably adjusted to a thickness of <10 .mu.m, more preferably 1 to 6 .mu.m, particularly preferably 2 to 3 .mu.m.

The antireflection coating may have a single-layer or multi-layer structure. Such single-layer or multi-layer antireflection coatings are known to a person skilled in the art and a person skilled in the art is able to select suitable materials and layer thicknesses of an antireflection coating or of the individual antireflection layers in a suitable manner. An antireflection coating with a one, two, three, four, five or six-layer structure is preferably selected. In the case of antireflection coatings with a two- or multi-layered structure, such a layer sequence is usually selected, in which an antireflection layer with a high refractive index adjoins an antireflective layer with a low refractive index. In other words, for such a It is preferred for a multilayer structure that antireflection layers with a low refractive index and antireflection layers with a high refractive index alternate alternately. In addition, further layers, for example adhesive layers (for example with a thickness of about 5 nm), which need not have an optical function, but are advantageous for the resistance, adhesion properties, climatic resistance, etc., can be incorporated. For example, it is also possible to replace the above antireflection coating by a mirror-coating, comprising one or more mirror-coating layers and, if appropriate, antireflection layers.

Examples of suitable antireflective coating materials include metals, non-metals such as silicon or boron, oxides, fluorides, silicides, borides, carbides, nitrides and sulfides of metals and the foregoing non-metals. These substances may be used singly or as a mixture of two or more of these materials.

Preferred metal or non-metal oxides include SiO, SiO ₂ , ZrO ₂ , Al ₂ O ₃ , TiO, TiO ₂ , Ti ₂ O ₃ , Ti ₃ O ₄ , CrO _x (where x = 1-3), such as Cr ₂ O ₃ , Y ₂ O ₃ , Yb ₂ O ₃ , MgO, Ta ₂ O ₅ , CeO ₂ and HfO ₂ .

Preferred fluorides include MgF ₂ , AIF ₃ , BaF ₂ , CaF ₂ , Na ₃ AIF ₆ and Na ₅ Al ₃ Fi ₄ .

Preferred metals include, for example, Cr, W, Ta and Ag.

It is particularly preferred to use SiO ₂ as the material for the last or outermost (based on the surface of the spectacle lens) antireflection layer, ie the antireflection layer, which is in contact with the hydrophobic and / or oleophobic coating.

The antireflection coating described above can be applied by conventional methods, wherein it is preferred to apply the individual antireflection layers by vacuum deposition or by sputtering. The layer thickness of the antireflection coating with a single-layer or multi-layer structure is fundamentally subject to no particular restriction. However, it is preferably adjusted to a thickness of <400 nm, preferably <300 nm, more preferably <250 nm. However, the minimum layer thickness of the antireflection coating is preferably about> 100 nm. In a multilayer structure of the antireflective coating, the thickness of each individual layer (ie, antireflection layer) is appropriately adjusted as stated above.

For example, such an antireflection coating can be made up of alternating high- or low-index layers of TiO ₂ or SiO ₂ with, for example, λ / 8-TiO ₂ , λ / 8-SiO _2> λ / 2-TiO ₂ and λ / 4. SiO ₂ , when λ stands for light with the wavelength of 550 nm. Such an antireflection coating with multiple layer structure can be produced, for example, by means of known PVD methods.

Suitable hydrophobic and / or oleophobic coatings are known to a person skilled in the art and in principle are not subject to any particular restriction, as long as a coating with hydrophobic and / or oleophobic properties results, which has sufficiently good adhesion properties, such as, for example, silane-based materials. The hydrophobic and / or oleophobic coating preferably comprises a silane having at least one fluorine-containing group, preferably having more than 20 carbon atoms. However, it can also be composed of a corresponding siloxane or silazane, which preferably comprises at least one fluorine-containing group. The silane having at least one fluorine-containing group is preferably based on a silane having at least one hydrolyzable group. Suitable hydrolyzable groups are not subject to any particular restriction and are known to a person skilled in the art. Examples of hydrolyzable groups bonded to a silicon atom are halogen atoms, such as chlorine, -N-alkyl groups, such as -N (CH ₃ ) ₂ or -N (C ₂ Hs) ₂ , alkoxy groups or isocyanate groups, where an alkoxy group, in particular a methoxy group or ethoxy group is preferred as a hydrolyzable group. It is always but also possible to use a silane with at least one fluorine-enthaitenden group carrying at least one hydroxyl group.

The silane having at least one fluorine-containing group preferably comprises one or more polyfluorinated group (s) or one or more perfluorinated ones

Group (s), wherein one or more polyfluorinated or perfluorinated alkyl group (s), one or more polyfluorinated or perfluorinated alkenyl group (s) and / or one or more polyfluorinated or perfluorinated polyether units containing group (s) are particularly preferred. Preferred polyether unit-containing groups comprise one or more - (CF ₂ ) _X O unit (s) where x = 1 to 10, with x = 2 to 3 being particularly preferred.

According to a preferred embodiment of the present invention, the silane has a fluorine-containing group and three hydrolyzable groups or hydroxyl groups.

Furthermore, it may be preferred for the hydrophobic and / or oleophobic coating to be built up from a polyfluorinated or perfluorinated hydrocarbon compound. The polyfluorinated or perfluorinated hydrocarbon compound is not subject to any significant limitation. However, it is preferred to use polytetrafluoroethylene as the polyfluorinated or perfluorinated hydrocarbon compound.

The hydrophobic and / or oleophobic coating is preferably composed exclusively of a silane having at least one fluorine-containing group or a polyfluorinated or perfluorinated hydrocarbon compound. However, it is also possible, a mixture of one or more of these silane (s) and / or one or more poly- or perfluorinated hydrocarbon compound (s), optionally with other inorganic, organometallic or organic auxiliaries for the hydrophobic and / or oleophobic coating, to use.

The hydrophobic and / or oleophobic coating can be applied by customary processes, it being preferred to apply this coating by vapor deposition, CVD processes or by a dipping process. The layer thickness of the hydrophobic and / or oleophobic coating is subject in principle to no particular restriction. However, it is preferably adjusted to a thickness of <50 nm, preferably <20 nm.

The plasma treatment is carried out after the application of the one or the last antireflective layer, if the antireflection coating has a multilayer structure, and before the application of a hydrophobic and / or oleophobic coating. According to the present invention, a plasma treatment is understood to mean a process in which the surface of the glass is brought into contact with plasma and the ions of the plasma change the surface chemically and / or physically in such a way that the adhesion of the hydrophobic substance to be applied subsequently and / or oleophobic coating is significantly improved.

In particular, the plasma treatment (a) in a separate plant before spielsweise a dip coating, (b) as a first step in the TopCoat- coating when the TopCoat coating is applied aufge¬ in a separate plant, (c) as a last step the antireflective coating when the TopCoat coating is applied in a separate unit, or (d) as the last process step before the TopCoat coating when the antireflective coating and the TopCoat coating (s) are applied in one unit.

The process gases suitable in the plasma treatment are not subject to any particular restriction. However, it is preferred to verwen¬ argon, oxygen, nitrogen, CF ₄ , or a mixture of two or more of the above substances. In particular, in the plasma treatment step, argon is used as the process gas. It is particularly advantageous to use in the plasma treatment step a mixture of argon and oxygen, wherein the ratio of argon to oxygen by volume ranges from 3: 1 to 1: 3. The ion energy in the plasma treatment step is preferably set in a range of about 1 eV to about 1000 eV, more preferably 5 eV to 500 eV, most preferably 50 to 100 eV.

The ionic current density in the plasma treatment step is preferably in a range from 10 ¹⁴ to 10 ¹⁹ ions / (cm ² s), more preferably from 10 ¹⁵ to 10 ¹⁸ ions / (cm ² s), with an ionic current density of about 10 ¹⁷ ions / (cm ² s) is most preferred.

The duration of the plasma treatment step is not subject to any particular restrictions. However, it is preferred to carry out the plasma treatment for 10 seconds to 10 minutes, more preferably 30 seconds to 2 minutes, typically 1 minute to 2 minutes.

The method according to the invention makes it possible to produce a spectacle lens which has a significantly improved adhesion between the antireflection coating and the hydrophobic and / or oleophobic coating. Because of this considerable improvement in adhesion, the service life or service life of the hydrophobic and / or oleophobic coating used is substantially increased.

As a test for the lifetime or service life of a hydrophobic and / or oleophobic coating, the following test is used, which simulates the daily cleaning of the spectacle lenses over a longer period of time:

In the service life test, a glass is clamped and loaded with at least 1000 strokes with a commercial cotton cloth or microfiber cloth and a contact force of about 10 N on a support surface with a radius of 1 cm. As a measure of the wear, the decrease in the surface energy (according to the Owens-Wendt method, which is described in "Estimation of the Surface Force Energy of Polymers", Owens DK, Wendt RG (1969) J. APPL. POLYM. SCI. , 13, 1741-1747; as liquids, water, diiodomethane and hexadecane are used in the Owens-Wendt method). Spectacle lenses made according to methods described in the prior art often fail after only 1000 strokes, which corresponds to a practical life of about 1/2 year. Spectacle lenses which are produced by the process according to the invention have a significantly improved service life. As a rule, ophthalmic lenses which are produced by the method according to the invention only precipitate after about 4000 to 6000 strokes, which corresponds to an extension of the service life by a factor of about 4 to 6.

The following example is given to further illustrate the invention without limiting it.

example

The antireflective coating and the hydrophobic and / or oleophobic coating were applied to a spectacle lens in an APS 904 system. A solitaire coating process with plasma treatment was carried out after application of the last SiO ₂ antireflective layer with the following parameters: (a) Gases: Ar, U ₂ , N ₂ or CF ₄ or mixtures thereof;

(b) gas flow (sccm; standard cubic centimeter): 6, 8, 10, 12, 15, 20, 25 or 30;

(c) bias voltage (V): 40, 60, 80, 100, 120 or 150;

(d) discharge current (A): 10, 20, 30, 40 or 50;

(e) time (s): 30, 60, 120 or 300.

Claims

claims

1. A process for the production of a spectacle lens with improved adhesion between seeing an antireflection or mirror coating applied to the spectacle lens, which has a monolayer or multilayer structure, and a hydrophobic and / or oleophobic coating, comprising

Steps:

(a) providing a spectacle lens; (b) optionally applying a hard layer to the surface of the spectacle lens

Spectacle lens,

(c) applying an antireflection coating or mirror coating, comprising one or more antireflective or mirroring layers, (d) carrying out a plasma treatment after application of the outer antireflection coating, and

(e) applying a hydrophobic and / or oleophobic coating.

2. The method of claim 1, wherein a plastic glass or mineral glass is used as the spectacle lens.

3. The method of claim 1 or 2, wherein a hard layer based on an acrylic polymer, a urethane polymer, a melamine polymer, a Sili¬ con resin or an inorganic material, in particular based on quartz, is used.

4. The method according to any one of the preceding claims, wherein the Materia¬ lien for anti-reflection or mirror coating metals, Nichtme¬ metals such as silicon or boron, oxides, fluorides, silicides, borides, carbides, nitrides and sulfides of metals and the Include above non-metals.

5. The method according to any one of the preceding claims, wherein the hydrophobic and / or oleophobic coating comprises a silane having at least one fluorine-containing group and / or a poly- or perfluorinated Kohlen¬ hydrogen compound.

6. The method according to any one of the preceding claims, wherein in the plasma treatment step, the process gas selected from the group consisting of argon, oxygen, nitrogen, and CF ₄ or a mixture of two or more thereof.

7. A method according to any one of the preceding claims, wherein the ion energy in the plasma treatment step is set in a range of 1 eV to 1000 eV.

8. A method according to any one of the preceding claims, wherein the ionic strength is set in the range of 10 ¹⁴ to 10 ¹⁹ l / (cm ² sec).