EP1763493A1

EP1763493A1 - Composition for treating glass-ceramic or glass to improve mechanical strength through curing of surface defects, treatment methods

Info

Publication number: EP1763493A1
Application number: EP05776412A
Authority: EP
Inventors: Pablo Vilato; Marie-Hélène ROUILLON; Caroline Faillat; Sophie Besson; Stéphane LOHOU; Olivier Gaume; Didier Le Couviour
Original assignee: Eurokera SNC
Current assignee: Eurokera SNC
Priority date: 2004-07-02
Filing date: 2005-06-15
Publication date: 2007-03-21
Also published as: WO2006013296A1; KR20070028485A; JP5661986B2; FR2872507A1; CN1984852A; FR2872507B1; KR101243196B1; JP2008504209A; US20090197026A1

Abstract

The invention concerns a composition for treating the surface of glass-ceramic in particular in plate form, flat or hollow glass, or in the form of fibers, suitable for application in thin layer on said glass-ceramic or said glass. It comprises, in aqueous medium, the following constituents (A) and (B): (A) at least one compound comprising at least one function f(A); and (B) at least one compound comprising at least one function f(B) capable of reacting with the function(s) f(A) of constituent (A) inside the thin layer applied on the glass-ceramic or the glass so as to transform the latter through polycondensation and/or polymerization into a solid layer, at least one of the compounds comprised in the definition of (A) and (B) containing at least one R-O- function bound to a silicon atom, R representing an alkyl radical, and at least part of the compounds containing at least one R-O- function bound to a silicon atom that may be in hydrolyzed form resulting from prehydrolysis or spontaneous hydrolysis occurring upon contact of the compound(s) with the aqueous medium.

Description

COMPOSITION FOR TREATING VITRQ CERAMIC OR GLASS FOR IMPROVING MECHANICAL STRENGTH BY TREATMENT OF SURFACE DEFECTS, METHODS OF TREATMENT

The present invention relates to a treatment composition of a glass-ceramic including plate, a glass, in particular a flat glass or a hollow glass (bottles, flasks, etc.), or a glass in the form of fibers, for improving the mechanical strength of said glass by healing surface defects thereof. It also relates to the corresponding treatment processes, as well as to the glasses thus treated.

International application WO 98/45216 describes a method of manufacturing hollow glass containers, with a waterproof surface, according to which is applied to the containers leaving the annealing arch downstream of the machine for manufacturing the glass containers hollow, a water-based treatment agent comprising:

(I) an aqueous-based composition containing organopolysiloxanes, prepared from an alkoxysilane having a functional group such as amino, alkylamino, dialkylamino, epoxy, etc. and alkoxysilanes selected from trialkoxysilanes, dialkoxysilanes and tetraalkoxysilanes; and

(II) a silicon-free component selected from waxes, partial esters of fatty acids and / or fatty acids, and which may contain a surfactant. The temperature of the glass surface during the application of the treatment agent amounts to at least 30 ^° C., being in particular from 30 ° to 150 ^° C. By this treatment, the resistance to prolonged use of the containers is improved.

In the international application WO 98/45217, the application of this coating agent as a second layer is described, the first layer being obtained from a treatment agent containing a trialkoxysilane and / or a dialkoxysilane and / or a tetraalkoxysilane or their hydrolysis and / or condensation products.

US Pat. No. 6,403,175 B1 discloses a cold treatment agent for hollow glass containers to reinforce them on the surface. This water-based agent contains at least the following components: a trialkoxysilane, a dialkoxysilane and / or a tetraalkoxysilane, their hydrolysis products and / or their condensation products; a water-soluble mixture of a polyol and a crosslinking agent of the polyol, the layer of cold treatment agent thus applied being subsequently subjected to crosslinking over a temperature range between 100 and 350 ^° C.

However, the Applicant Company has sought to further improve the mechanical strength of glass-ceramic plates, glasses, in particular flat glass or hollow glass, or glass in the form of fibers, and has developed a new composition of coating providing excellent results, said composition being a polymerizable or polycondensable aqueous composition on the surface of the glass to form a thin film otherwise reacting with the glass through functions SiOH or SiOR (R = alkyl).

The present invention therefore firstly relates to a composition for treating the surface of a glass-ceramic, in particular a plate, or a glass, in particular a flat glass or a hollow glass, or to a glass in the form of fibers, said composition being capable of being applied in a thin layer to said glass-ceramic or said glass, characterized in that it comprises, in an aqueous medium, the following constituents (A) and (B):

(A) at least one compound having at least one function f ( _A ); and

(B) at least one compound having at least one function f ( _B ) capable of reacting with the function (s) f ( _A ) of component (A) within the thin layer applied to the glass-ceramic or glass in order to transform the by polycondensation and / or polymerization into a solid layer,

at least one of the compounds falling within the definition of (A) and (B) comprising at least one R-O- function attached to a silicon atom,

R representing an alkyl radical, and

at least a part of the compounds comprising at least one RO- function attached to a silicon atom that can be in a hydrolysed form resulting from spontaneous prehydrolysis or hydrolysis occurring on contact of the compound (s) with the aqueous medium.

The alkyl radical for R is in particular a linear or branched C 1 -C 6 alkyl radical.

The functions f ( _A ) and f ( _B ) can in particular be chosen from the functions -NH ₂ , -NH-, epoxy, vinyl, (meth) acrylate, isocyanate, alcohol.

In particular, we can choose the functions f (A) / f (B) of the components respectively (A) and (B) from the families indicated in the table below, with the pathway of formation of the thin layer by activated polymerization. under UV or thermally:

Regarding the thermal pathway, it should be noted that it includes the polymerization at room temperature which may be possible in some cases.

By way of examples of compounds falling within the definition of constituents (A) and (B), mention may be made of:

Melamine, ethylenediamine and 2- (2-aminoethylamino) ethanol (compounds having no SiOR or SiOH function);

Bisphenol derivatives (A) (compounds having no SiOR or SiOH function);

Monomeric or oligomeric (meth) acrylates (compounds having no SiOR or SiOH function); The compounds of formula (I):

A-SI (R ¹ MOR ² ) * _* (I)

in which :

- A is a hydrocarbon radical which has at least one group selected from amino, alkylamino, dialkylamino, epoxy, acryloxy, methacryloxy, vinyl, aryl, cyano, isocyanato, ureido, thiocyanato, mercapto, sulfane or silicon-bonded halogen groups directly or via an aliphatic or aromatic hydrocarbon radical;

- R ¹ represents an alkyl group, in particular C 1 -C 3, or A as defined above;

R ² represents a C 1 -C 6 alkyl group which may be substituted with an alkyl [polyethylene glycol] residue; - x = 0 or 1 or 2.

In particular, the following combinations (A) / (B) can be mentioned:

• methacryloxypropyltrimethoxysilane / polyethylene glycol diacrylate; Methacryloxypropyltrimethoxysilane / glycidoxypropylmethyldiethoxysilane; and

3-aminopropyltriethoxysilane / glycidoxypropylmethyl-diethoxysilane. According to a particular embodiment, the functions f ( _A ) of the constituent (A) are -NH ₂ and / or -NH- functions, and the ffo functions of the constituent (B) are epoxy functions, the ratio of the number of functions -N-

H component (A) to the number of epoxy functions is between 0.3: 1 and

3: 1, terminals included, especially between 0.5: 1 and 1.5: 1, inclusive.

There may be mentioned a particular composition according to the invention which comprises 3-aminopropyltriethoxysilane as component (A) and glycidoxypropylmethyl-diethoxysilane as component (B), the latter being advantageously introduced in the prehydrolysed state.

Once introduced into the aqueous medium, the constituents (A) and (B), at least one of which has at least one -SiOR function, undergo a hydrolysis of the function or functions -SiOR in -SiOH, in a period of time more or less long after contact with water. In some cases, an acid such as hydrochloric acid or acetic acid must be added to catalyze the hydrolysis.

Even at room temperature, the condensation of -SiOH functions in -SiO-Si- groups can begin. That's how there can be reactions

(A) + (A); (A) + (B) and (B) + (B) by the -SiOH functions, these reactions being able under certain conditions to participate in the formation of a three-dimensional siloxane network. However, the constituents (A) and (B) and the operating conditions will advantageously be chosen so that this network is only very partially formed in aqueous solution.

According to the present invention, the composition is intended to be applied to the glass-ceramic or the glass to be treated and to form a thin layer by polymerization or polycondensation by reaction of the functions f ( _A ) of the constituent (A) on the functions f ( _B ) of the constituent (B). Moreover, the polycondensation product reacts with the glass-ceramic or glass via the SiOH and SiOR radicals, thus making it possible to cure the surface defects of the latter: glazes, cracks, shocks, etc. The film thus formed is intended to improve the mechanical strength of glass-ceramic or glass. The composition according to the invention may furthermore comprise:

(Cl) at least one polymerization or polycondensation catalyst of the constituents (A) and (B); and / or (C2) at least one UV or thermal radical polymerization initiator, or UV cationic agent, depending on the method of forming the hard coating used.

Advantageously, the constituent (Cl) is or comprises a tertiary amine, such as triethanolamine and diethanolamine propanediol. In general, examples of tertiary amines, those of formula (III): R ⁵ /

R ⁵ - N (III)

R ⁷

wherein R ⁵ to R ⁷ each independently represent an alkyl or hydroxyalkyl group. The presence of at least one catalyst makes it possible to reduce the duration and temperature of polymerization, avoiding, in the case of coating vials or the like, the use of an additional polymerization arch and making it possible to work at the temperature of the bottles. leaving the annealing arch (at 150 ⁰ C for example), as will be described below.

Radical polymerization initiators (C2) are for example mixtures comprising benzophenone, as lirgacure ^® 500 marketed by the company "CIBA SPECIALTY CHEMICALS."

The composition of the invention may furthermore comprise:

(D) at least one anti-scratch and rubbing agent selected from waxes, partial esters of fatty acids and fatty acids, and polyurethanes and other polymers known for their protective function such as acrylic polymers; and or

(E) at least one emulsion polymer whose Tg is between 0 and 100 ⁰ C, in particular between 10 and 80 ⁰ C; and / or (F) at least one surfactant, such as anionic or nonionic surfactant.

As examples of waxes, mention may be made of polyethylene waxes, whether or not they are oxidized.

The waxes, partial esters of fatty acids and fatty acids may be introduced into the composition in the state associated with a surfactant.

The protective agents (D) are thermoplastic and have elastic slip properties. Their inclusion in the formed thin film contributes to the protection against scratches and wear and handling frictions. The emulsion polymers (E) are in particular chosen from emulsion acrylic copolymers, such as those of the "Hycar®" series marketed by the company "NOVEON".

As examples of surfactants (F), mention may be made of polyoxyethylene fatty ethers, such as CISH ₃₅ (OCH ₂ CH ₂ ) 100H, known under the name "Brij®97" as well as copolymers poly (ethylene oxide) -poly (propylene oxide) -poly (ethylene oxide) triblocks. The surfactants used in the examples below are also mentioned.

The composition according to the invention can thus comprise, in an aqueous medium, for a total of 100 parts by weight: up to 25 parts by weight of component (A); up to 25 parts by weight of component (B);

0 to 25 parts by weight of component (Cl) as defined above;

0 to 25 parts by weight of the component (C2) as defined above; 0 to 25 parts by weight of component (D) as defined above; and

0 to 25 parts by weight of component (E) as defined above; and

0 to 25 parts by weight of component (F) as defined above, the aforementioned amounts being indicated as solids, and, when an agent is introduced in the form of an aqueous solution or emulsion, the amount of water of this solution or emulsion then forming part of the aqueous medium of the composition.

The composition according to the invention advantageously has a viscosity at ambient temperature of between 1 and 3 centipoises according to the rotating cylinder method (Brookfield Rheovisco LV viscometer, speed = 60 rpm, accessory low viscosity).

The subject of the present invention is also a process for treating the glass-ceramic surface or glass to improve its mechanical resistance by healing surface defects, characterized in that a thin film is applied to the glass-ceramic parts or glass to be treated. of the composition as defined in one of claims 1 to 15 in a thickness of up to 3 microns, and that a polymerization or polycondensation of said composition is conducted. The composition according to the invention may be prepared for its application by mixing its constituents, generally at the time of use, in various ways:

When the composition according to the invention contains the constituents (A) + (B) + water, it can be prepared by first mixing (A) + (B), then combining this mixture with the water at the time of mixing. 'employment.

It is also possible to pre-hydrolyze (A) and / or (B).

In the case where catalysts and / or additives are present, they can be mixed with water, before mixing with (A) + (B) at the time of use. It is also possible, in the case where one of the constituents (A) or (B) has been hydrolyzed, to incorporate the additives into the unhydrolyzed component.

The application of the composition is advantageously carried out by spraying or dipping ("dip coating"). In order to form the thin, hard layer, it is possible to conduct a drying, for example for a few seconds, then a passage under UV lamps, the UV treatment having a duration for example of a few seconds to 30 seconds.

The thermal polymerization or polycondensation can be carried out at a temperature of, for example, 100 to 200 ^° C. for 5 to 20 minutes. However, the temperature and the duration of the treatment depend on the system used. Thus, there may be systems that allow the formation of the hard thin film thermally at room temperature in an almost instantaneous time. In the case where a hollow glass is coated, it is possible to proceed by depositing the composition by spraying on the hollow glass after the annealing arch, the temperature of the hollow glass during the spraying being 10-150 ^° C., and

when the composition does not contain a catalyst, by passing the hollow glass in a polymerization arch at a temperature of 100 to 220 ^° C. for a lapse of time of a few seconds to 10 minutes; and

when the composition contains a catalyst, allowing the polymerization to proceed without passing through a polymerization arch. The present invention also relates to a glass-ceramic, a flat glass or hollow glass treated with a composition as defined above, according to the process as defined above, as well as on glass fibers, in particular optical fibers (for example examples useful for dental lamps) treated with a composition as defined above, according to the process as defined above.

The present invention also relates to the use of a composition as defined above, for improving the mechanical strength of glass-ceramic or glass by healing defects of its surface. The following examples illustrate the present invention without, however, limiting its scope. In these examples, parts and percentages are by weight unless otherwise indicated.

In these examples:

the "SR610" is a polyethylene glycol diacrylate 600 marketed by the company "CRAY VALLEY"; the mixture "CRAY VALLEY" is a mixture constituted by 67% of "SR610" as defined above and 33% of an aliphatic oligomer diacrylate marketed under the name "CN 132" by the company CRAY VALLEY. Since "CN 132" is poorly miscible in water, a predissolution of it in the "SR610" is necessary; wax "GK6006" is a polyethylene wax with 25% solids, marketed by the company "MORELLS"; the "OG25" wax is a polyethylene wax containing 25% solids, sold by the company "TRUB EMULSION CHEMIE AG";

- I "Irgacure ^® 500" is the trade name of a radical polymerization initiator sold by the company "CIBA", consisting of 50% benzophenone and 50% 1-hydroxycyclohexyl phenyl ketone. EXAMPLE 1a: Flat glasses with a coating layer formed by drying and UV curing.

(a) Preparation of the coating composition

The following formulation was used, the amounts being given in part by weight:

1,5-Methacryloxypropyltrimethoxysilane

Polyethylene glycol 600 "SR610" Diacrylate

0.5

Wax "GK6006" 1.5

Tensio-active agent of the family of modified polysiloxanes, 0.1 marketed by BYK under the name "Byk 341"

Irgacure 500 0.15

Water supplement to

100

A glass coating composition was prepared by hydrolyzing the silane of the formulation in water for 24 hours and then adding the other components of the formulation.

(bO Formation of the coating layer on indented flat glasses

The composition thus obtained was deposited on a batch of flat glasses (70 × 70 × 3.8 mm) on which defects had been created by Vickers indentation with a diamond pyramidal tip and an applied force of 5ON.

The deposit was made by immersion ("dip-coating") at a controlled speed of 500 mm / min to ensure a uniform thickness. This deposit was made 24 hours after the induction so that the crack propagation was stabilized and the constraints around the defect created were relaxed. The glasses were then dried for 10 minutes at 100 ^° C., and then the coated layer was subjected to UV polymerization for 25 seconds, the characteristics of the UV emitter being the following: distance from the surface of the substrate relative to at the lamp: 5 cm; - iron-doped mercury lamp (UVH Strahler type F); power: 150 W / cm.

(c) Tripod bending test

Tripod bending was broken into glasses thus coated, extending the created defect. This test was carried out without UV aging and climatic coatings formed.

A batch of 10 flat glasses was not coated and served as a control. The tripod breaking results express the modulus of rupture (MOR) (MPa) and serve as an assessment of the performance of the composition reinforcement. The reinforcement results for the coating represent the difference of the modulus of rupture in the bending test between the flat control glasses and the treated flat glasses.

The results are reported in Table 1 below. Table 1

The formulation of this example shows a very strong reinforcing effect of weakened glasses, this reinforcement being in fact 107.8% compared to uncoated indented flat glasses.

The graph in Figure 1 expresses the percentage of cumulative failure as a function of the modulus of rupture in MPa. The curve representing the 10 coated flat glass samples is shifted to the higher breaking moduli with respect to the curve of the ten uncoated flat glass samples. The coating formed from the composition of this example therefore gives greater mechanical strength to the glass.

EXAMPLES Ib and Ic: Flat glasses with a coating layer formed by drying and then UV crosslinking.

The following formulations were used, the amounts being given in parts by weight:

Example Ib

Aminopropyltriethoxysilane 1 "CRAY VALLEY" mixture 10 Sodium dodecyl sulphate (surfactant) 0.3 Irgacure 500 0.25 Water supplement 100

Example Ic

Methacryloxypropyltrimethoxysilane 1

Mix "CRAY VALLEY" 10

Acrylated surfactant marketed by the "BYK" Company under ^'1 the name "BYK 3500 UV"

Copolymer surfactant marketed under the name "Gantrez"

Sodium dodecyl sulfate (surfactant) 0.5

Water supplement to 100

For each of the formulations of Examples Ib and Ic, the procedure was as in Example 1a, except that the crosslinking times are of the order of 20 seconds. The results are expressed by the graph of Figure 2 of the accompanying drawing. Each treatment must be compared to its respective witness. Both formulations appear to have reinforcements of the order of 100%.

EXAMPLE 2 Flat glasses with a coating layer formed by thermal crosslinking

(a) Preparation of the coating composition

The following formulation was used, the amounts being given in parts by weight:

Methacryloxypropyltrimethoxysilane 1

Glycidoxypropylmethyldiethoxysilane 1

Wax "GK6006" 1.5

Water supplement to

100

A glass coating composition was prepared by the following procedure:

The two silanes were premixed for 5 minutes, then the water was added and the silanes were hydrolyzed with vigorous stirring for 30 minutes. Then we added the wax.

(b) Formation of the coating layer on indented flat glasses

The procedure was as in Example 1 (b), except that instead of drying followed by UV polymerization, a heat treatment was carried out for 25 minutes at 240 ^° C.

(c) Tripod bending test

The same test as in Example 1 (c) was carried out on the glasses thus coated. The results obtained are presented in Table 2 below as well as in FIG. 3.

Table 2

EXAMPLES 3a to 3d: Flat glasses with a coating layer formed by thermal crosslinking

(a) Preparation of coating compositions

On the one hand, a first can containing raminopropyltriethoxysilane and glycidoxypropylmethyldiethoxysilane were prepared and mixed for 5 to 7 minutes (Example 3a) or 10 minutes (Examples 3b, 3c, 3d) and on the other hand a second can containing the polyethylene wax, the polyurethane and the water, and then the contents of the two cans were mixed 30 minutes before application.

(b) Formation of the coating layer on indented flat glasses

The procedure was then as in Example 2 (b), except that the treatment

(polymerization) heat was carried out at 200 ⁰ C for 20 minutes.

(c) Tripod bending test

The same test as in Example 1 (c) was carried out on the glasses thus coated from the composition of Example 3b.

The results are reported in Table 3 below as well as in Figure 4:

Table 3

In the graph of FIG. 4, the curve representing the ten coated flat glass samples is shifted to the highest breakup modules relative to the curve of the ten uncoated flat glass samples.

The coating formed from the composition of Example 3b therefore gives greater mechanical strength to the glass. (d) Tripod bending test on indented flat glasses with UV and climatic aging of the coating formed from the composition of Example 3b

Two aging tests are used, namely the WOM (Weather-O-Meter) test, in which the flat glass samples are subjected to 540 h UV exposure, and the CV (Variable Climate) test, according to which flat glasses undergo cycles for 15 days from - 10 ° C / + 90 ° C, a cycle lasting 8 hours, at 95% RH.

The results are reported in Figure 5 and in Table 4 below:

Table 4

The reinforcement provided by the coating based on the composition of Example 3b is not modified after the aging tests WOM and CV.

(e) Visualization with the naked eye of the appearance of the coating based on the composition of Example 3b (after WOM and CV)

The glass comprising the coating based on the composition of Example 3b was not degraded after 540 hours UV exposure. It was not altered by moisture under the conditions of the CV test described above. EXAMPLES 4a and 4b Preparation of compositions according to the invention with pre-hydrolysis of at least one silane

A composition is prepared as in Example 3a, except that pre-hydrolysis of the two silanes (Example 4a) or glycidoxypropylmethyldiethoxysilane (Example 4b) is carried out with all the water for 15 minutes.

EXAMPLES 5a and 5b Preparation of compositions according to the invention with introduction of catalysts

A composition was prepared as in Example 3a, except that 0.15 parts of triethanolamine (Example 5a) was added to the second can.

A composition as in Example 3c was also prepared except that 0.075 part of triethanolamine and 0.075 part of diethanolamine propanediol (Example 5b) were added to the second can.

EXAMPLE 6 Influence of the Prehydrolysis of qlycidoxypropylmethyldiethoxysilane

The FTIR spectrograms of the formulation of Example 3a with simultaneous hydrolysis at 23 ° C of the two silanes are identical with or without pre¬ hydrolysis of glycidoxypropylmethyldiethoxysilane after 23 minutes of mixing.

From 23 minutes, the hydrolysis of 3-aminopropyltriethoxysilane and glycidoxypropylmethyl-diethoxysilane is complete. The pre-hydrolysis of glycidoxypropylmethyldiethoxysilane does not affect the hydrolysis reaction kinetics of the two silanes. In contrast, pre-hydrolysis of glycidoxypropylmethyldiethoxysilane influences reinforcement over time. The flat glass reinforcement results as a function of the maturation time (Ih, 3h and 6h or 8h) for the formulation of Examples 3a and 4b are illustrated in Figures 6 and 7, respectively. Table 5: Summary table of the reinforcements with the formulation of Examples 3a and 4b to the tripod test on flat glasses indented with 5ON

σ = standard deviation

The reinforcement on samples of flat glasses indented at 50 N degrades over time. From 3 hours of life of the mixture, the reinforcement without pre-hydrolysis of glycidoxypropylmethyl-diethoxysilane (= simultaneous hydrolysis) and with pre-hydrolysis of glycidoxypropylmethyldiethoxysilane drops. Nevertheless, a pre-hydrolysis seems to attenuate this reduction of the reinforcing properties: it remains at 46% after 8 hours of aging of the formulation while the reinforcement with the formulation of Example 3a (without pre-hydrolysis prior to glycidoxypropylmethyl-diethoxysilane) is more than 14% after 6:30 of maturation of the mixture.

It is therefore recommended a procedure which consists in first hydrolysing the glycidoxypropylmethyldiethoxysilane a few minutes, 5 to 10 minutes, to obtain a stable and lasting strength reinforcement.

EXAMPLE 7 Evolution of the viscosity

The viscosity of the formulation of Examples 3 and 4 with or without pre-hydrolysis of glycidoxypropylmethyl-diethoxysilane is dependent on the temperature at which the mixture is subjected (20 ^° C. or 40 ^° C.). She changes all the more quickly as the temperature is high. The viscosity of the formulation is also dependent on the nature of the polyethylene wax used (OG25 or GK6006). In the presence of GK6006 (Example 3d), the mixture appears stable over time while an increase in viscosity is observed when the formulation contains IOG25.

EXAMPLE 8 Optimization of the polymerization (time and temperature) with tertiary amine catalysts

The use of a tertiary amine triethylamine makes it possible to shorten the polymerization time by half (10 minutes against 20 minutes) and to reduce the polymerization temperature by 50 ^° C. (150 ^° C. against 200 ^° C.) while preserving a level of about 90% reinforcement.

The optimization of the formulation towards a less energy consuming formulation is favorable to a more economical use of the polymerization arch installed in line after the cold end.

Table 6 below is a summary table of the results obtained.

Table 6

EXAMPLE 9: Mechanical strengthening of the edges of glazings. Flat glass tests for automotive and building applications

The defects on the edges are less severe than the defects created with an indentation of 50 N. The cutting and the shaping of the glass create smaller defects on the edges. To simulate the small flaws of the edge, apply a force of 5 N during the indentation. The size (indentation at 50 N or 5 N) and the nature of the defect (indentation or shaping) lead to different reinforcement values for the coating of Example 3a.

Indeed, the strengthening of the edges after coating of the flat glasses and 4-point flexion is 17.1%, whereas for indentation at 5 N and 50 N, 55.3 and 177.3% respectively are obtained.

Table 7 below is a summary table of the results obtained.

Table 7

Examples IQa and IQb: Mechanical reinforcement obtained on bottles

The following formulations were used:

The glass coating compositions were prepared by the following procedure.

The epoxysilane was hydrolyzed for 10 minutes in water, then the aminosilane was added and hydrolyzed for 20 minutes before adding GK 6006 wax.

The test was conducted on a bottle production line using a 16 section IS machine, 32 molds, 300 Burgundy and 410 g.

The bottles are taken out of the arch before the cold treatment, then treated by cold spraying under the following conditions: bottles upside down on spinners, two nozzles for treating respectively the bottom and the barrel of the bottles: the spray nozzle specific for the barrel was 16 cm from the bottle; its spray axis was 11 cm from the bottom of the same bottle.

The nozzle for the bottom was located 16 cm from the bottle; it sprayed the bole up to 3 cm from the bottom.

The rotational speed of the spinner was 120 rpm. ; the spraying times were chosen to make complete turns. The atomizing air pressure was 5.5 bar. The parameters were set to obtain a sliding angle of approximately 8 ° with the formulation of Example 11a:

- Nozzle drum: 4 liters / h;

- Nozzle melts: 4 liters / h;

- Spray for 2 seconds

Part of the bottles removed is treated by spraying

(cold bottles), dried for 15 minutes, then undergoes a study heat treatment of 20 minutes at 200 ⁰ C. The other bottles serve as a control. Each series consists of 320 bottles (10 bottles per mold). The entire surface of the bottles is treated, as well as the bottom. The thickness of the coating is 150 to 300 nm.

Bottles treated with the formulation of Example 10a have a sliding angle of 8 °; those treated with the formulation of Example 10b have a sliding angle of 20 °. The resistance of the bottles is evaluated by the internal pressure test (AGR device). The break histograms are shown in Figures 8 and 9 and the average breaking pressures in Table 8 below.

Table 8

EXAMPLE 11 Addition of an Emulsion Polymer to the Composition: Coating formed by Thermal Crosslinking

(a) Preparation of the coating composition

The following formulation was used, the amounts being given in parts by weight:

Glycidoxypropylmethyldiethoxysilane 1.0

3-Aminopropyltriethoxysilane 0.3

Emulsion of a copolymer having a Tg of + 36 ° C., 2.6 sold by the company "Noveon" under the trademark Hycar® 26391

Water supplement to

100

To prepare the coating composition, the epoxysilane is solubilized for 5 minutes in water. Then the amino silane is added and mixed for 15 minutes. Finally, the copolymer emulsion is added and mixed for 3 minutes.

The same formulation was also prepared without the emulsion. (bθ Deposition of coating on indented flat glasses

The coating compositions thus prepared are deposited on ION-indented glass samples by soaking these glasses in said compositions at 50 cm. min ^-1 , followed by air drying of the samples for 10 min, followed by heat treatment at 200 ⁰ C for 20 min.

(c) Tripod bending test

Example (c) was used as in the example, the results obtained being presented in Table 9 below as well as in Figure 10.

Table 9

EXAMPLE 12: Mechanical Strengthening of Vitroceramic Cooking Hobs

A composition varying from that of Example 10a is sprayed onto a Kerablack type glass-ceramic plate, a mark registered by Eurokéra, only with a wax content of GK 6006 of 2% instead of 1.5%.

Again the epoxysilane was hydrolyzed for 10 minutes in water, then the aminosilane was added and hydrolyzed for 20 minutes before adding GK 6006 wax.

The tested plates are said to be smooth-smooth, their two faces being smooth (as opposed to the plates reinforced mechanically by formation of pins, reliefs on one or two sides, by calendering between rolls with reliefs complementary). Their dimensions are 300 mm x 300 mm x 3 mm thick.

It is sprayed at a flow rate of 11 l / h, and a nozzle displacement speed of 0.45 m / s with 4 translations. A continuous film is formed on one side of the plate, dried for 10 minutes in the open air and then heated at 200 ^° C. for 20 minutes.

The vitroceramic plates meet the standard household appliances NF EN-60-335-2-6.

Next, a set of untreated plates according to the invention and a set of treated plates are subjected to mechanical strength tests.

The plates are kept horizontal so as to leave a central free zone of 240 mm × 240 mm, the reinforcing layer according to the invention oriented, where appropriate on the lower face. The plates are subjected to three series of impacts from above, located on twelve impact zones according to standard NF EN 60-068-2-75 (Norwegian hammer). The energy of the impact instrument is 0.7 J.

The breakage rates are:

- 32% for untreated plates; - 5.5% for coated plates.

Another set of vitroceramic plates treated according to the invention is subjected to aging on a radiant focus of 145 mm of useful diameter, positioned under the plates, at their center. The coatings of the invention, always on the underside, are heated in cycles at 450-600 ^° C. for 30 minutes and allowed to cool for 30 minutes.

The same impact tests as previously carried out on plates having aged on radiants during

- 18 hours: 3% of breakage; - 350 hours: 8.3% of breakage.

It is of interest that the improvement in mechanical strength provided by the invention is maintained by the current use - on the hearth - of the glass-ceramic plates.

Claims

1. A composition for treating the surface of a glass-ceramic, in particular a plate, or a glass, in particular a flat glass or a hollow glass, or a glass in the form of fibers, said composition being capable of being applied in a thin layer to said glass-ceramic or said glass, characterized in that it comprises, in an aqueous medium, the following constituents (A) and (B):

(A) at least one compound having at least one function f ( _A ); and

at least one of the compounds falling within the definition of (A) and (B) comprising at least one R-O- function attached to a silicon atom, R representing an alkyl radical, and

at least a part of the compounds comprising at least one RO- function attached to a silicon atom that may be in a hydrolysed form resulting from a spontaneous prehydrolysis or hydrolysis occurring during the contact of the compound (s) with the aqueous medium .

2. Composition according to Claim 1, characterized in that the alkyl radical R is a linear or branched C1-Cs alkyl radical.

3. Composition according to one of claims 1 and 2, characterized in that the functions f ( _A ) and f ( _B ) are chosen from the functions -NH ₂ , -NH-, epoxy, vinyl, (meth) acrylate , isocyanate and alcohol.

4. Composition according to one of claims 1 to 3, characterized in that the functions f (A) / f (B) of the constituents respectively (A) and (B) are chosen from the following families:

- amine / epoxy; amine / (meth) acrylate;

epoxy / (meth) acrylate;

(meth) acrylate / (meth) acrylate;

vinyl / (meth) acrylate; - vinyl / vinyl;

epoxy / epoxy;

isocyanate / alcohol.

5. Composition according to one of claims 1 to 4, characterized in that the constituents (A) and (B) are chosen from: • melamine, ethylenediamine and 2- (2-aminoethylamino) ethanol;

• bisphenol derivatives (A);

Monomeric or oligomeric (meth) acrylates;

The compounds of formula (I):

A-Si (R ¹ ) _x (OR ² ) ₃ -x (I) in which:

6. Composition according to one of claims 1 to 5, characterized in that the combinations (A) / (B) are chosen from:

• methacryloxypropyltrimethoxysilane / polyethylene glycol diacrylate;

Methacryloxypropyltrimethoxysilane / glycidoxypropylmethyldiethoxysilane; and

3-aminopropyltriethoxysilane / glycidoxypropylmethyl-diethoxysilane.

7. Composition according to one of claims 1 to 6, characterized in that it further comprises: (Cl) at least one polymerization or polycondensation catalyst of the constituents (A) and (B); and / or (C2) at least one UV or thermal radical polymerization initiator, or UV cationic polymer.

8. Composition according to claim 7, characterized in that the constituent (Cl) is or comprises a tertiary amine, such as triethanolamine and diethanolamine propanediol.

9. Composition according to one of claims 7 and 8, characterized in that the radical polymerization initiators are mixtures comprising benzophenone.

10. Composition according to one of claims 1 to 9, characterized in that it further comprises:

(D) at least one anti-scratch and rubbing agent selected from waxes, partial fatty acid esters and fatty acids, and polyurethanes and other polymers known for their protective function such as acrylic polymers.

11. Composition according to one of claims 1 to 10, characterized in that it further comprises: (E) at least one emulsion polymer whose Tg is between

0 and 100 ⁰ C, in particular between 10 and 80 ⁰ C.

12. Composition according to one of claims 1 to 11, characterized in that it comprises:

(F) at least one surfactant.

13. Composition according to one of claims 1 to 12, characterized in that it comprises, in aqueous medium, for a total of 100 parts by weight:

up to 25 parts by weight of component (A);

up to 25 parts by weight of component (B); 0 to 25 parts by weight of component (Cl) as defined in claim 7;

0 to 25 parts by weight of component (C2) as defined in claim 7; 0 to 25 parts by weight of component (D) as defined in claim 10; and 0 to 25 parts by weight of component (E) as defined in claim 11; 0 to 25 parts by weight of the constituent (F) as defined in claim 12. the aforementioned amounts being indicated as solids and, when an agent is introduced in the form of an aqueous solution or emulsion, the quantity of water of this solution or emulsion then forming part of the aqueous medium of the composition.

14. Composition according to one of claims 1 to 13, characterized in that the functions f ( _A ) of the constituent (A) are -NH ₂ and / or - NH-, and the functions f ( _B ) of component (B) are epoxy functions, the ratio of the number of -NH functions of the component (A) to the number of epoxy functions is between 0.3: 1 and 3: 1, inclusive, in particular between 0.5: 1 and 1.5: 1, inclusive.

15. Composition according to one of claims 1 to 14, characterized in that it has a viscosity at room temperature of between 1 and 3 centipoise according to the rotary cylinder method.

16. Process for treating the glass-ceramic surface or glass to improve the mechanical strength by healing surface defects, characterized in that a thin film of the composition as defined is applied to the portions of glass-ceramic or glass to be treated. to one of claims 1 to 15 in a thickness of up to 3 microns, and a polymerization or polycondensation of said composition.

17. The method of claim 16, characterized in that one leads a drying of the applied thin film, then a passage under UV lamps, the treatment having a duration for example of a few seconds to 30 seconds.

18. Process according to Claim 16, characterized in that the polymerization or polycondensation is carried out thermally.

19. The method of claim 16, wherein the glass to be coated is a hollow glass, characterized in that one proceeds by depositing the spray composition on the hollow glass after the annealing arch, the temperature of the hollow glass during the spraying being 10-150 ^° C., and

when the composition contains no catalyst, by passing the hollow glass in a polymerization arch at a temperature of

100 to 220 ⁰ C for a period of time of a few seconds to 10 minutes; and

when the composition contains a catalyst, allowing the polymerization to proceed without passing through a polymerization arch.

20. Glass ceramic plate, flat glass or hollow glass treated with a composition as defined in one of claims 1 to 15, according to the process as defined in one of claims 16 to 19.

21. Glass fibers, especially optical fibers, treated with a composition as defined in one of claims 1 to 15, according to the process as defined in one of claims 16 to 19.

22. Use of a composition as defined in one of claims 1 to 15, for improving the mechanical strength of the glass-ceramic or glass by healing defects on its surface.