FR2899342A1 - Composition for hardening organic optical glass, e.g. polyamide glass for sunglasses, contains polysiloxane varnish, solvent, adhesion promoter and optional hardening catalyst - Google Patents

Abstract

A composition (I) for the treatment of optical glass, especially organic glass, contains (a) at least 80 (preferably at least 90) wt% polysiloxane varnish (based on dry substance), (b) solvent(s), (c) optionally a hardening catalyst and (d) adhesion promoter(s). Independent claims are included for (1) a method for the treatment of glass as above, by pretreating the substrate with an alkaline solution containing a surface preparation agent, preferably at 45-60[deg]C, washing the pretreated substrate, drying (preferably with infrared radiation), cooling, immersing in (I), prepolymerising the varnish and then polymerising, preferably at 90-120[deg]C (2) a method for adding a UV stabiliser to (I), especially a stabiliser with a sec. or tert. amino group, preferably a derivative of 2,2,6,6-tetramethyl-piperidine (II), involves adding a dilute solution of nitric acid in 2-methoxypropan-1-ol to composition (I), stirring and then adding (II) .

Description

COMPOSITION AND PROCESS FOR TREATING ORGANIC GLASSES

  Field of the Invention The present invention relates to the treatment of organic glass, especially ophthalmic or solar glass. The purpose of this treatment is to harden the surface of the glass, to make it resistant against scratches, and it can receive anti-reflective treatment, mirror or staining.

  STATE OF THE ART In the field of optics, particularly ophthalmic and solar glasses, appeared on the market a few years ago a material previously only used for frames: polyamide. Under the tradenames and / or trademarks of Trogamid (Degussa) or Grilamid o (EMS), polyamides 4,12 or copolymers of dodecane dioic acid and Cyclohexanamine, 4,4'-methylenebis (2-methylcyclohexanamine ) have been introduced to the eyeglass lens market as substitutes for polycarbonate (another type of thermoplastic glass). Their use is becoming widespread in Europe. But the technical solutions to protect them from scratches and shocks are still rather imperfect.

  Indeed, the thermoplastic polymer glasses, such as polyamide, have a two-dimensional network, and are less resistant than thermosetting glasses that have a three-dimensional network. In particular, the thermoplastic polymer glasses need to be covered with a hardening protective layer. For this, we usually use a varnish.

  The varnishes used must meet a number of requirements, among which: a compatibility of their solvents with the glass intended to be coated; direct adhesion to the substrate, namely organic glass, under conventional operating conditions; a hardness at least equivalent to the varnishes already used on solar polycarbonate; a colorability of up to about 90% light absorptions with dyes already used by the profession; an implementation of said varnishes in coating machines already used by the main manufacturers of sunglasses; a machine life (that is, the possibility of using a quantity of product ready for use for an extended period of time) acceptable; - as low a level of toxicity as possible to the varnish and their solvents for the users (production personnel).

  Compositions having a hardening effect on organic type optical glass are already known.

  By way of example, patent application FR 2 551 223 describes a composition for the hardening of the surface of lenses prepared from polyamide resins, comprising a polyfunctional monomeric acrylic ester, a photoinitiator and a diluent. This composition, applied by photo-induced polymerization, improves the impact and wear resistance of the lenses. The curing effect is achieved using a particular combination of photoinitiator, i.e., a combination of a hydrogen subtractive type photoinitiator and an α-cleavage type photoinitiator of the double bond .

  The glasses thus obtained, however, have a low hardness and are difficult to colorable and not prone to receive anti-reflection treatment or mirror, including vacuum metallization. The present inventors have therefore sought other bases of varnishes and other additives to prepare compositions to meet the criteria set out above, knowing that the first condition for a varnish can be used in the present context is the compatibility of its solvents with the substrate.

  Patent Application FR 2 858 691 describes: an anti-scratch polymerizable composition comprising: a) at least one alkoxysilane and / or at least one hydrolyzate thereof, b) anisotropic particles of at least one metal oxide and / or at least one metal oxyhydroxide, c) optionally a polymerization catalyst, as well as its application in ophthalmic optics. The anisotropic particles indeed confer improved scratch resistance for polysiloxane coatings containing them. In addition, it is specified that the substrates that are suitable for optical articles according to the invention are polycarbonate substrates, those obtained by polymerization of alkyl methacrylates, as well as those obtained by polymerization of allyl carbonates of polyols, such as diethylene glycol bis allyl carbonate sold under the trade name CR 39.

  The present inventors have also developed a varnish based on alkoxysiloxane. But unlike this patent application FR 2 858 691, the composition according to the invention does not contain anisotropic particles having a shape factor and very specific dimensions, and more particularly makes it possible to coat polyamide substrates.

  OBJECT OF THE INVENTION A first object of the invention is a composition for the treatment of optical glass, especially of organic type, comprising a polysiloxane-type varnish, at least one solvent, at least one adhesion promoter, and optionally a catalyst for curing and a stabilizer against UV rays.

  The subject of the invention is also a process for treating optical glass, in particular of organic type.

  Yet another subject of the invention is the use of a stabilizing agent against W radiation, namely a compound comprising a secondary or tertiary amine function, said compound preferably being a derivative of piperidine, and even more preferentially a derivative of 2,2,6,6-tetramethylpiperidine, for stabilizing the system consisting of polysiloxane varnish and organic glass.

  Finally, the subject of the invention is also a process for introducing a stabilizing agent against W radiation, namely a compound comprising a secondary or tertiary amine function, said compound preferably being a derivative of piperidine, and even more preferably a derivative of 2,2,6,6-tetramethylpiperidine, in the composition for the treatment of optical glass according to the invention.

Description of the invention

  The present invention is applicable to organic glasses, more particularly to thermoplastic glasses, and even more particularly to polyamide glasses, such as polyamide 12 (also known as nylon).

  The invention relates to a composition for the treatment of optical glass, especially of organic type, characterized in that it comprises: a polysiloxane-type varnish; optionally a hardening catalyst; at least one solvent; an adhesion promoter; and optionally a UV stabilizer. Varnish: The varnish used in the composition according to the invention is a varnish in which the polysiloxane represents by weight at least 80% of the dry matter of said varnish, and preferably at least 90%. The polysiloxanes used in the composition according to the invention are epoxyalkoxysilanes. Some of these products are known as such. Mixtures of several polysiloxanes can be used. The preferred epoxyalkoxysilanes according to the invention comprise an epoxy group. The preferred epoxyalkoxysilanes according to the invention comprise at least two alkoxy groups, the latter being directly bonded to the silicon atom. A preferred epoxyalkoxysilane is an alkoxysilane having a (3- (3,4-epoxycyclohexyl) moiety, such as 3- (3,4-epoxycyclohexyl) ethyltrimethoxysilane.) Particularly preferred epoxyalkoxysilanes have the formula (1):

  In which: R 1 is an alkyl group of 1 to 6 carbon atoms, preferably a methyl or ethyl group, R 2 is a methyl group or an atom, wherein R 1 is an alkyl group of 1 to 6 carbon atoms, preferably a methyl or ethyl group, R 2 is a methyl group or an atom. of hydrogen, a is an integer from 1 to 6, b represents the integers 0,1 or 2. Preferred examples of such epoxysilanes are γ-glycidoxypropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane, the latter being particularly preferred.

  As epoxysilanes, epoxydialkoxysilanes such as γ-glycidoxypropylmethyl-dimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxyethoxypropylmethyldimethoxysilane can also be used.

  The epoxydialkoxysilanes are preferably used at lower levels than the epoxytrialkoxysilanes mentioned above. Other preferred alkoxysilanes have the following formula: R3cR4dSiZ4- (c + d) (II) Formula wherein R3 and R4 are selected from substituted or unsubstituted alkyl, methacryloxyalkyl, alkenyl and aryl groups (examples of substituted alkyl groups usable are the halogenated alkyls, in particular chlorinated or fluorinated alkyls); Z is an alkoxy, alkoxyalkoxy or acyloxy group; c and d take the values 0, 1 or 2; and c + d is 0.1 or 2. This formula (II) includes the following compounds which are exemplified herein: (1) tetraalkoxysilanes, such as methylsilicate, ethylsilicate, n-propylsilicate, isopropylsilicate, n-butylsilicate, sec-butylsilicate, and t-butylsilicate, and / or (2) trialkoxysilanes, trialkoxyalkoxysilanes or triacyloxysilanes such as methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriméthoxyéthoxysilane, vinyltriacéto-xysilane, phenyltrimethoxysilane, phenyltriethoxysilane, y-chloropropyltriméhoxysilane , γ-trifluoropropyltrimethoxysilane, methacryloxypropyltrimethoxysilane, and / or (3) dialkoxysilanes, such as: dimethyldimethoxysilane, ychloropropylmethyldimethoxysilane and methylphenyldimethoxysilane.

  The use of an alkoxysilane hydrolyzate (s) is possible, and can be carried out according to a technique known from the prior art. Thus, the techniques set forth in EP 614,957 and US 4,211,823 can be employed. The silane hydrolyzate is prepared by adding water or a solution of mineral acid such as hydrochloric acid or sulfuric acid to the silane (s). It is also possible to perform hydrolysis without adding solvents and simply using the alcohol or carboxylic acid formed in the reaction between water and the alkoxysilane (s). These solvents can also be substituted with other solvents, such as alcohols, ketones, alkyl chlorides, and aromatic solvents. Hydrolysis with an aqueous hydrochloric acid solution is preferred.

  The polymerization conditions of the varnish (temperature and / or time) have a considerable influence on the hardness, the colorability and the adhesion of the varnish. In an advantageous embodiment with commonly used polyamides, the polymerization is carried out at a temperature of between 90 ° C. and 120 ° C., for example for a period of the order of two hours. What limits the usable temperature zone is, on the one hand, the deformation temperature of the substrate. On the other hand, below 90 C, the adhesion to the substrate is in some cases more satisfactory. Typically, the polymerization in the absence of catalyst on polyamide 4,12 is carried out at a temperature of between 90 and 110 [deg.] C. (advantageously at about 100 ° C.) and that on polyamide 12 at a temperature of between 110 and 120 ° C. (advantageously close to 120 C, if the substrate allows). At the end of the polymerization, the varnish according to the invention has a refractive index of about 1.5.

  The curing catalyst: A curing catalyst may be used in the composition according to the invention. Some of these known catalysts for curing polysiloxane lacquers may be suitable. Mention may in particular be made, as examples of hardening catalysts, of aluminum compounds, and in particular of aluminum compounds chosen from: aluminum chelates, and compounds of formula (III) or (IV) detailed below: AI (OCR) n (OR ') 3_n (III) O (R'O) 3-nAI (OSIR "3) n (IV) in which: R and R' are linear-chain alkyl groups or branched from 1 to 10 carbon atoms,

  R "is a linear or branched chain alkyl group of 1 to 10 carbon atoms, a phenyl group, a group wherein R has the meaning indicated above, and n is an integer of 1 to 3. An aluminum chelate is a compound formed by the reaction of an aluminum alkoxide with nitrogen and sulfur free sequestering agents containing oxygen as a coordination atom.

  The aluminum chelate is preferably selected from the compounds of formula (V): ## STR5 ##

  wherein: X is a group OL where L is an alkyl group of 1 to 10 carbon atoms, Y is at least one ligand produced from a compound of formula (1) or (2): (1) MI In which: M1, M2, M3 and M4 are alkyl groups of 1 to 10 carbon atoms, and v is an integer which takes the values of 0.1 or 2. 10 As Examples of compounds of formula (V) that can be used in the context of the present invention include aluminum acetylacetonate, ethylacetoacetate, aluminum bisacetylacetonate, alumminium acetylacetonate bisethylacetoacetate and di-n-butoxide monoethylacetoacetate. of aluminum and aluminum dipropoxide monomethylacetoacetate.

  The compounds of formula (III) or (IV) are preferably chosen from those in which R 'is an isopropyl or ethyl group, and R and R "are preferably methyl groups. the composition aluminum acetylacetonate, in a proportion of 0.1 to 5% by weight of the total weight of the composition.

  The use of a curing catalyst decreases the polymerization time, but also the duration of use of the soaking bath. For this reason, it may be advantageous, especially for small series, not to use a catalyst, although this increases the polymerization time.

  The solvent: The compositions of the invention also comprise an organic solvent. For practical reasons, a solvent is preferred, the boiling point of which, at atmospheric pressure, is between 70 ° C. and 140 ° C. As organic solvent which may be used according to the invention, mention may be made of alcohols, esters and ketones. tetrahydropyran, tetrahydrofuran and mixtures thereof. The esters are preferably chosen from acetates and, in particular, ethyl acetate. Ethers may be used in the composition according to the invention as solvents provided that the boiling point is not too high.

  Butanol and isobutanol are known solvents for thermoplastics. But in the case of polyamide glasses, they give rise to problems that are also encountered with other types of solvents, namely: - the problem of bleaching, that is to say the formation of a veil or a white surface on the substrate 25 under the effect of the solvent; - And the problem of damage to the substrate from the point of view of its impact resistance, that is to say the reduction of the impact resistance of the surface under the effect of the solvent. These two problems, which may appear separately or together, render the organic glass unsuitable for use as optical glass.

  Moreover, some solvents do not make it possible to obtain a good adhesion on the thermoplastic organic glasses of the usual varnishes. And finally, as will be explained below, other solvents that may be suitable are removed from the composition because their use is impractical in industrial production.

  For practical reasons related to the constraints of an industrial production, the solvent used in the composition according to the invention must meet the following requirements: be liquid at ambient temperature (that is to say have a melting point below 15 C, and preferably less than 10 ° C., have a boiling point of less than 200 ° C., and preferably less than 160 ° C., so that it can be evaporated at atmospheric pressure, if the solvent is an alcohol, have a chain. Linear comprising not more than 6 carbons, and not more than 2 alcohol functions.

  The inventors have found that methoxy-2-propan-1-ol makes it possible to satisfy all these criteria. Other secondary or tertiary alcohols, such as diacetone alcohol, may also be suitable, but there may be the problem of drying: relatively volatile solvents are preferred so that the drying can take place at atmospheric pressure under IR irradiation, without the use of vacuum equipment.

  Similarly, tert-butyl alcohol could be employed, but it could then have a melting point problem: this alcohol has a too high melting point, ie 25 C.

  The glycol ether may also be suitable as a solvent. Ketones can also be used with the exception of acetone which is too volatile. For example, methyl isobutyl ketone may be quite suitable.

  Finally, a mixture of solvents for the composition according to the invention is also conceivable, such as, for example, a methanol / methoxy-2-propan-1-ol mixture.

  The adhesion promoter: The polyamides (constituents of the optical glass substrate) being thermoplastic, it is necessary to use an adhesion promoter which will allow the varnish to adhere directly to the substrate and also to make it possible. an anti-reflection treatment. The adhesion promoter must achieve an adhesion such that the optical glass can be colored after the coating during the coloring operation in a 95 C boiling water bath without being damaged or weakened. The preferred adhesion promoter in the context of the present invention is GPTMS (3-glycidoxypropyl) trimethoxysilane, which reacts very easily, thanks to its epoxy functions, with the amino groups (previously activated by an alkaline surface treatment). The yield obtained and the nature of the covalent bond created by the reaction between the epoxy and the amine, provide sufficient levels of adhesion to the polyamide thus making the hot coloring steps possible.

  Preferably, the adhesion promoter will be used in a proportion of 1 to 50% by weight relative to the dry matter of the composition of the varnish according to the invention, and particularly preferably in a proportion of 1 to 30%. .

  Stabilization agent against UV rays: The UV stabilization agent makes it possible to respond to the problem of oxidation of the polymers, which causes a yellowing of the substrate, a possible loss of transparency, the appearance of surface cracks. , and that plays on the mechanical properties by decreasing flexibility and tensile strength. This oxidation is accelerated by temperature and UV rays.

  In the context of the invention, a compound based on a secondary or tertiary amine, preferably a secondary or tertiary amine in which the nitrogen atom is part of a saturated hydrocarbon ring, is used as UV stabilizer. at 4.5 or 6 carbon atoms, such as a pyrrolidine or piperidine derivative, and preferably based on a 2,2,6,6-tetramethylpiperidine derivative, and preferably an amine belonging to the family of HALS (Hindered Amines Light Stabilizers).

  Examples of HALS used in the composition according to the invention have the following formulas: 1) Monomer: Tinuvin 770 (CIBA), namely [bis- (2,2,6,6-tetramethyl-4-piperidyl) sebacate] ## STR2 ## ## According to the invention, the introduction of stabilizing agent against UV rays in the composition according to the invention is carried out in an acid medium to prevent this stabilizing agent against UV rays from reacting with the epoxides of the adhesion promoter; the latter can be a GPTMS type compound. Said agent comprises a secondary or tertiary amine function; a secondary or tertiary amine, and even more preferably an amine in which the nitrogen atom is part of a 4,5 or 6 carbon saturated hydrocarbon ring, such as a pyrrolidine derivative or piperidine. The most preferred amines are 2,2,6,6-tetramethylpiperidine derivatives; in this family, amines belonging to the family of HALS (Hindered Amines Light Stabilizers) are preferred.

  The introduction is carried out by a process which comprises the following steps: a) addition of a dilute mineral solution, in particular of nitric acid (for example 2.69 ×) in a suitable solvent, such as methoxy-2 propan-1-ol, to the appropriate lacquer to be deposited on polyamide, b) stirring (typically at room temperature and for several hours, for example 16 hours), c) addition of the UV stabilizing agent, HALS-type preference (e.g. the product sold under the trademark Tinuvin 765 (CIBA), namely bis- (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, at about 0). 15% relative to the solids content of the varnish).

  The invention also relates to a method for treating optical glass, particularly of organic type, said method being characterized in that it comprises the following steps: a) pretreatment of the substrate in an alkaline solution containing a surface-preparation agent, preferably at a temperature of between 45 ° C. and 60 ° C., b) at least one step of rinsing the pretreated substrate, c) drying of the substrate, preferably by infra-red radiation, for example at a temperature of 80 ° C., d) cooling of the substrate. substrate, preferably at a temperature between 10 and 30 C, e) dipping the substrate in a composition for the treatment of optical glass according to the invention, said composition comprising a varnish, f) prepolymerization of the varnish, g) polymerization of the varnish preferably at a temperature between 90 C and 120 C.

  As a surface preparation agent, the inventors have successfully used for the pretreatment the Chemopclean 201P product (which consists of a mixture of 45% sodium hydroxide with 35% sodium gluconate and 20% trisodium phosphate, and whose pH is 14) at a concentration of 3% by weight at 55 ° C for 4 minutes in an ultrasonic tank; the first and second rinses were carried out for 4 minutes each.

  The prepolymerization step is advantageously carried out by infra-red heating. The heating must be carried out in such a way as to prevent the solvents from evaporating too quickly and remaining trapped in the form of bubbles in the varnish. That is why a progressive heating is preferred. In addition, this allows the polymerization reaction to be carried out homogeneously at the lacquer-substrate interface. The glasses obtained are then "dust-free".

  The invention also relates to the use of stabilizing agent W, based on a secondary or tertiary amine, preferably based on a 2,2,6,6-tetramethylpiperidine derivative, and preferably an amine belonging to the HALS family (Hindered Amines Light Stabilizers) HALS to stabilize a polysiloxane / organic glass varnish system.

  The examples which follow illustrate the invention without, however, limiting its scope.

  Examples: In Examples 1 and 2, an adhesion test was performed in order to verify this property on the composition according to the invention. It consists of the following steps: a) on the surface of the varnish is made a grid 25 of 11 longitudinal lines and 11 lateral lines 1 mm apart, b) a 3M adhesive tape is applied for 30 seconds, then torn off. hard hit. c) the number of squares not torn off is counted 30 d) the test is repeated 5 times.

  In addition, a steel wool abrasion test was performed by rubbing the surface of the varnished glass with n 000 steel wool under a load of 200 g 30 times and then noting the extent of the damage. . Example 3 describes the process according to the invention for the treatment of optical glass, in particular of organic glass.

  Finally, Example 4 describes the method of introducing a UV stabilizer, in this case "Tinuvin 765" (CIBA), into the composition according to the invention.

  EXAMPLE 1 According to the Invention: One kilogram of varnish marketed by Isochem under the name of TE 1- 15 8, the main solvent of which is primary butanol and which contains, in percentages relative to its dry matter, 17% of AMEO (3-aminopropyltrimethoxysilane), 5% of GPTMS, 75% of alkoxysilane (methoxy and ethoxysilane) and 3% of acetic acid, 200 g of diacetone alcohol are added. The initial solids content of the varnish is 30% by weight, and the final rate of the mixture obtained is 25% by weight. The concentration of tertiary alcohol is then 16.7% by weight. An injected nylon 12 glass (Grilamid TR 90) is then varnished by dipping with the varnish resulting from this operation. The glass remains perfectly transparent after the polymerization of the varnish carried out in 2 hours at 120 ° C., whereas the varnish TE 1-8 leads to an almost immediate opacification of the glass, due to the attack of the nylon 12 by the primary butanol. After 24 hours, the adhesion and abrasion resistance of the steel wool are tested, and the results are in accordance with industry standards. A staining bath is then applied using the BPI brown dye for 30 minutes at 92 ° C. A 70% absorption is then obtained. Continued staining does not improve absorption, but leads to an attack of the varnish and / or to a detachment thereof.

  Example 2 According to the Invention: Starting from one kilogram of varnish marketed by LGChem under the name of LGCOM-TN11-MP (PM), which contains, in percentages relative to its dry matter, 67% of alkoxysilane, 3% acetic acid, 29% GPTMS (as adhesion promoter), 1% aluminum acetylacetonate (as a curing catalyst), and solids content about 35% in weight. This lacquer has as its main solvent 2-methoxy-propan-1-ol, with a methanol content of 15% by weight. To this varnish is added 400 g of methoxy-2-propan-1-ol. The final solids content is thus reduced to 25% by weight, and the concentration of methanol to 10.7%. A glass injected nylon 12 (Grilamid TR 90) is then varnished by dipping with the varnish resulting from this operation. The glass remains perfectly transparent after the polymerization of the varnish carried out in 2 hours at 110 C, while the initial varnish leads to an almost immediate opacification of the glass, due to the attack of nylon 12 with methanol. After 24 hours, the adhesion and abrasion resistance of the steel wool are tested, and the results are in line with industry standards. The glass immersed for 5 hours in boiling water remains intact.

  A staining bath is then applied using BPI brown dye (Brain Power Incorporated) for 10 minutes at 92 ° C. An absorption of 70% is then obtained.

  The continuation of the coloring made possible by the remarkable adhesion of the varnish and its colorability makes it possible to reach an absorption greater than 90% after 30 minutes of immersion in the coloring bath.

  Example 3 According to the Invention: The polyamide glasses are treated in a dip varnishing machine equipped with ultrasonic tanks. In the first tank, an alkaline solution containing a surface preparation agent (Chemopclean 201P) at a concentration of 3% by weight is brought to 55 ° C. and is subjected to ultrasound. The rinsing is carried out first with running water, then with demineralized water at 40 C. Each step is carried out for 4 minutes, then the glasses are dried for 4 minutes by infra-red heat and then cooled before to be soaked for 8 minutes in the composition for the optical glass treatment described in Examples 1 and 2. The glasses are then introduced into the polymerization furnace.

  EXAMPLE 4 According to the Invention: Process for Introducing Stabilizing Agent for W Radiation A one kilogram of composition for the treatment of optical glass according to the invention is added 75 g of a solution of nitric acid to 2.69% in methoxy-2-propan-1-ol. Stir at room temperature for 16 hours. To this mixture is added 0.15% by weight of stabilizer against UV rays of HALS type (Tinuvin 765, namely bis (1,2,2,6,6-pentamethyl-4-piperidyl). sebacate) relative to the solids content of the varnish, about 0.38 g.

Claims (10)

  1. Composition for the treatment of optical glass including organic type, characterized in that it comprises: - a polysiloxane-type varnish, where the polysiloxane represents by weight at least 80% of the dry matter, and preferably at least 90% of the weight of the dry matter, of said varnish, at least one solvent, optionally a curing catalyst, at least one adhesion promoter. 15   2. Composition according to claim 1, characterized in that it further comprises a stabilizer against W radiation.   3. Composition according to claim 1 or 2, characterized in that the polysiloxane is an epoxyalkoxysilane comprising an epoxy group and at least two alkoxy groups. 25   4. Composition according to any one of claims 1 to 3, characterized in that the solvent is characterized by a boiling point, at atmospheric pressure, between 70 C and 140 C.   5. Composition according to any one of claims 1 to 4, characterized in that the solvent is methoxy-2-propan-1-ol.   6. Composition according to any one of claims 1 to 5, characterized in that the adhesion promoter is (3-glycidoxypropyl) trimethoxysilane (GPTMS).   7. Composition according to any one of claims 1 to 6, characterized in that the stabilizing agent against UV radiation is a secondary or tertiary amine functional compound, a derivative of the preferentially tetramethylpiperidine.   8. Process for the treatment of optical glass, in particular of organic type, said process comprising the following steps: a) pretreatment of the substrate in an alkaline solution containing a surface-preparation agent, preferably at a temperature of between 45 ° C. and 60 ° C. B) at least one step of rinsing the pretreated substrate, c) drying the substrate, preferably by infra-red rays, d) cooling the substrate, e) dipping the substrate in a composition for the treatment of optical glass according to l any one of claims 1 to 7, said composition comprising a varnish, f) prepolymerization of the varnish, g) polymerization of the varnish, preferably at a temperature between 90 ° C and 120 ° C., preferably comprising a piperidine, and even more a derivative of the 2,2,6,6-   9. Use of a stabilizing agent against UV rays, said agent comprising a secondary or tertiary amine function, said agent preferably being a derivative of piperidine, and even more preferably a derivative of 2.2 , 6,6-tetramethylpiperidine, for stabilizing a composition for the treatment of optical glass according to any one of claims 1 to 7.   10. A method for introducing a stabilizing agent against UV rays, said agent comprising a secondary or tertiary amine function, said agent preferably being a derivative of piperidine, and even more preferably a derivative of 2, 2,6,6-tetramethylpiperidine in the composition for the treatment of optical glass according to any one of claims 1 to 7, said process comprising the following steps: a) addition of a dilute nitric acid solution in methoxy-2-propan-1-ol to a composition for the treatment of optical glass according to any one of claims 2 to 7, b) stirring, c) adding the stabilizing agent against UV rays. 30