EP1274659A1

EP1274659A1 - Glass body with improved strength

Info

Publication number: EP1274659A1
Application number: EP01936193A
Authority: EP
Inventors: Andreas Weber; Roland Bürkle; Silke Deutschbein; Andreas Habeck; Reiner Mauch
Original assignee: Schott Glaswerke AG
Current assignee: Schott AG
Priority date: 2000-04-18
Filing date: 2001-04-05
Publication date: 2003-01-15
Also published as: DE10019355A1; TW593185B; US20040071960A1; DE10191422D2; WO2001079128A2; CN1380876A; KR20020026883A; AU6217401A; JP2003531088A

Description

Vitreous body with increased strength

The invention relates to glass bodies of any shape, for example in the form of flat panes or in three-dimensional form of larger thickness dimensions.

Glass bodies of this type require particularly high strength, in particular surface strength, in numerous applications. Chemical or thermal treatments can be used to achieve this.

When the glass is thermally hardened, compressive stresses are frozen on the surface, while tensile stresses are frozen in the core due to the lower cooling rate. The width of the compressive stress zone is about 1/5 of the glass thickness. However, thermal hardening is limited to panes with thicknesses> 3 mm.

In contrast to thermal hardening, chemical hardening is based on the fact that the compressive stresses in the glass surface are achieved by changing the composition of the surface area in relation to the glass interior. In most cases this will

Change achieved by an alkali ion exchange at temperatures below the transformation temperature Tg. The glass is treated in a potassium nitrate melt at about 50-150 ° C below Tg for several hours. The exchange of Na for K creates a compressive stress zone, the depth of which is approx. 60 - 150 μm. This too

The process is therefore limited to thicker glasses> 0.7 mm. In addition, after chemical hardening, the glass must be polished for optical or electronic applications. This process step in turn increases the cost of production and, in the case of thin glasses (<0.3 mm), also leads to high losses due to breakage. The methods mentioned are therefore not to be used for thin glasses, such as are used in particular for displays or for data storage or for electronic applications.

With a small thickness of the glass, in particular with thicknesses <1 mm, or due to the manufacturing process for three-dimensional glass bodies, the previously known methods for increasing the strength of glass, such as thermal and chemical hardening, are ruled out because these methods are too time-consuming or one for Optical, electrical, electronic and optoelectronic applications produce unusable surface that has to be reworked with a complex polishing process. Particularly in applications where very thin glass (<0.3 mm) is used, an increase in strength is particularly important, as this would otherwise break too easily. In addition, thermal hardening is only possible for glasses with a thermal expansion coefficient of> 7 ppm / ° C. Especially in the above Applications are used due to the required thermal geometry stability glasses with a thermal expansion coefficient of <7 ppm / ° C.

The relatively low practical strength of glass compared to the theoretical strength is caused in particular by injuries and defects in the glass surface. It therefore makes sense to protect the surface with a coating. For example, DE 36 15 227 A1 describes a method with which flat glass has a scratch-resistant splinter coating

Plastic is coated, whereby a plastic powder is melted on the still hot glass surface. However, this method does not achieve a surface quality which is sufficient for glass substrates for use in displays or for data carriers. US Pat. No. 5,476,692 describes a method for improving the strength of glass containers using an organic resin, which is produced by polymerization on the glass. With this method, the surface of the glass is protected and thus more stable against impact and pressure from the outside, but an increase in the glass strength due to the build-up of compressive or tensile stress in the layer or in the glass is not described.

US Pat. No. 5,455,087 also describes a method for increasing the strength of glass containers by polymerization on the glass surface. Here too, the increase in strength is achieved only by the mechanical protective action and not, as described in the method according to the invention, by mechanical prestressing of the polymer layer. The importance of the tear propagation strength of the polymers is also not dealt with in the publications available to date.

The invention has for its object to provide a glass body of any type and shape with a higher strength. In particular, a high surface strength should be achieved with the least possible manufacturing effort and low manufacturing costs.

This object is solved by the features of the independent claims.

The invention is therefore based on a vitreous body, which consists of a.

Base body and a layer applied to this is built.

However, it is ensured that the applied layer is under a defined compressive stress or under a defined tensile stress.

The layer either has its own tension, which becomes effective when it is applied to the glass surface, or it receives it

Post-treatment tension. When applying a layer that is under compressive stress, the external tensile stress must first overcome this compressive stress before the glass breaks. On the other hand, if the applied layer is under tensile stress, compressive stress is generated in the region of the glass near the surface. This must also be done when creating an external one

Tension must first be overcome before the glass breaks.

This defined mechanically pre-stressed layer can consist of organic, inorganic and organic / inorganic materials. In addition to the mechanical prestressing of the applied layer, the tear resistance of the polymer is an important factor in polymer layers in order to increase the mechanical stability of the polymer / glass composite. In the method according to the invention, the selected material, the type of coating, or a suitable aftertreatment ensures the generation of a defined mechanical layer tension. Dip coating, spin coating, rolling, spraying and vacuum processes, such as sputtering, plasma polymerization, or plasma-assisted chemical deposition from the vapor phase can be used as possible coating methods

(PECVD) can be used.

All materials that can be produced with the method according to the invention are therefore suitable as layer materials. Thermoplastics, thermosets and elastomers can be used as organic polymers. For example, polymers such as Polyvinyl alcohols, polyacrylates, polyarylates, polyesters, polysilicones etc. or also materials containing so-called Ormocers and nanoparticles are applied to the glass by the process according to the invention in such a way that defined tensile or compressive stresses are set. This happens on the one hand through the

Selection of the suitable polymer with regard to molecular weight, Degree of hydrolysis, purity, crosslinkable functional groups and by an appropriate aftertreatment, which can be carried out thermally or photochemically (for example UV curing) or autocatalytically. The layer tension is generated by drying and crosslinking the polymer. This process also affects the tear resistance (ASTM D

264) of the polymer. In a preferred embodiment, the range of tear resistance is 10 N / mm, in a particularly preferred range it is in the range of 11-15 N / mm. Values above 10 N / mm mean that they are so-called "notch-resistant" elastomers, which have a significantly higher tear and tear resistance than standard products.

In order to achieve a higher strength and a high chemical resistance, the glass substrate can also be coated several times. A first layer is applied that is under a defined tensile or compressive stress. Around this mechanically pre-stressed layer e.g. To make it more resistant to chemicals, a second layer is applied, which provides this protection.

With the sputtering method, the setting of a certain one is also possible by a suitable choice of the process parameters

Layer tension possible. Then come materials such as metal oxides (e.g. aluminum oxide), metal nitrides (e.g. aluminum nitride), metal oxynitrides ( _e.g. Al _x O _y N _z ), metal carbides, metal oxycarbides, metal carbonitrides, semiconductor oxides ( _e.g. silicon oxide), semiconductor nitrides ( _e.g. silicon nitride), semiconductor oxynitrides (e.g. SiO _x N _y ), semiconductor carbides, semiconductor oxicarbides (e.g.

SiO-P _y ), semiconductor carbonitrides (eg SiC _x N _y ) or metals (eg chromium) or mixtures of these materials. Plasma polymers can be generated from a variety of organic and organometallic volatile compounds. Depending on the coating conditions, plasma polymers can also be deposited with a defined tensile or compressive stress. In the plasma-assisted sputtering process and in In plasma polymerization, the layer tension is adjusted, in particular, by a bias voltage which is applied to the glass to be coated. This bias voltage on the substrate can be generated by applying a DC voltage, a low-frequency voltage, a medium-frequency voltage or a high-frequency voltage to the

Substrate.

The vacuum arc process is particularly well suited to achieving layers with high mechanical strengths from an economic point of view.

The tensile or compressive stress of the applied layer is in the range of 100-1000 MPa, preferably 200-600 MPa and particularly preferably 300-500 MPa. The glass can be coated on one or both sides. The layer thickness depends on

Layer material at 0.05 - 50 μm. In the case of plasma polymers and sputtered layers, the layer thickness is preferably in the range of 0.05-0.5 μm and particularly preferably 0.1-0.3 μm. In the case of the polymer layers applied from the liquid phase, the layer thickness is in the range from 0.5 to 50 μm and, in a particularly preferred embodiment, from 1 to 10 μm.

In a particularly preferred embodiment, the coating is carried out directly after the hot shaping, that is to say on the glass ribbon. An additional increase in surface strength can be achieved in this way. Because the glass is provided with a protective layer immediately after production, e.g. Scratches or signs of corrosion on the glass surface can be prevented.

Due to the mechanical tension in the layer material, the adhesion of the layer material to the glass is of particular importance.

If this adhesion between the layer and the glass is too low, the layer loosens due to the layer tension from the glass or cracks. For adequate adhesion of the layer to the glass, it is therefore expedient to improve the adhesion of the layer by suitable pretreatment of the glass. This can be done by appropriate cleaning of the glass surface with aqueous or organic solutions. Other known methods for improving the adhesive strength of coatings made of glass are corona pretreatment. flame treatment, plasma pretreatment in vacuum, UV pretreatment, ozone pretreatment, UV / ozone pretreatment. To improve the adhesion of silicone polymers, special adhesion promoters such as silanols, hexamethyldisilazane, aminosilanes or polydimethylphenylsiloxane are also used.

By coating the glass on both sides with a layer that is under tensile or compressive stress, e.g. the

Surface strength of the glass can be increased from 580 MPa to 2,350 MPa, which is in the range of intrinsic strength.

If not only the surface of a flat glass substrate, but also the edges of a glass substrate is provided with a layer that is under mechanical compressive or tensile stress, this increases the surface and edge strength. This is particularly important in the case of thin glass substrates of <0.3 mm, since there the edges cannot be ground with the usual edge processing methods.

In particular, thin glasses with a thickness of less than 0.3 mm, preferably glasses with thicknesses in the range of 0.03-0.2 mm, can now be hardened by the process according to the invention and can thus also be used for applications in which otherwise only Glasses with a thickness greater than 0.3 mm can be used. Is used to harden the

Glass transparent and according to the inventive method heat-resistant materials, these glasses can be used as substrates, for example for the production of displays such as LCDs or PLEDs. In this way, stable, flexible displays can be produced using the method according to the invention.

In a particularly advantageous embodiment, these layers can perform other functions in addition to their strength-increasing effect by the process according to the invention. For example, they can also act as a diffusion barrier against easily movable alkali ions or as reflective layers for reflective displays.

If the transparency of the glass substrate is not required, metallic layers can also be used to generate layer stresses. Particularly suitable are Cr layers and Ta layers in α modification, which at low process pressures (<4 μbaή and high

Separation services are deposited.

When Cr or Ta is sputtered, a tensile stress is found in the metallic layer, which essentially depends on the process pressure during the sputtering. The lower the process pressure, the higher the

Tension due to the higher kinetic energy of the applied layer molecules. At process pressures> 10 μbar, the layer tension becomes negligibly small. In addition, the sputter rate drops sharply due to the lower ion energy of the Ar ⁺ ions.

Another application of the method according to the invention is in the production of data carriers made of glass, in particular so-called hard disks made of glass. To ensure the mechanical stability of these glass hard disks, they are usually subjected to chemical hardening. However, this chemical hardening has some disadvantages such as long process times, surface contamination. So they have to Glass substrates for hard disks can be polished and washed after chemical hardening. These processes are also very time consuming. By means of the method according to the invention, these processes are no longer necessary and the glass hardened by the method according to the invention can be used for the production of hard disks without further pretreatments.

Another application of the method according to the invention is in the production of printed circuit boards in which a thin glass film with a thickness of 30-100 μm is used instead of glass fabric. This is done by coating with an epoxy resin and the subsequent one

Curing by exposure to light or heat creates a toughened layer on the glass, increasing its surface strength. A copper foil is then laminated onto the glass treated in this way and the electrical circuit carriers are produced by structuring the copper and fitting it with further electrical components. The

Surface strength is measured using a ring-on-ring method (ROR) based on DIN 52292 or DRAFT DIN 52300. The measuring apparatus consists of two concentric steel rings, a support ring (radius 20 mm) and a load ring (radius 4 mm). A square sample (50 mm x 50 mm) is placed between the two load rings and the load on the glass is increased in a defined manner via the upper load ring. An anisotropic stress state is generated in the thin glass sample. The tests are carried out with a linearly increasing force effect, a force-controlled stress rate of 2 MPa / s being specified. The stress is increased until the glass breaks.

Non-linear force-stress relationships are taken into account for the calculation of the breaking stresses. The breaking stresses are given in the unit MPa and evaluated according to DIN 55303-7. The values calculated from this estimation method are then as

Strength values of the glasses tested. Various measuring methods are available for determining layer stresses in metallic or oxidic thin and thick layers. This measurement is carried out relatively simply by bending a thin glass strip which is coated with the method according to the invention. The mechanical layer stress is calculated from the basic mechanical data of the glass, its geometry, the measured bending and the layer thickness. The procedure is in the scriptures

E. I. Bromley, J.N. Randall, D.C. Flanders and R.W. Mountain, "A Technique for the Determination of Stress in Thin Films"

J. Vac. Be. Technol. B 1 (4), Oct.-Dec. 1983, pp. 1364-1366 and

H, Guckel, T. Randazzo and D.W. Burns "A Simple Technique for the Determination of Mechanical Strain in Thin Films with Applications to Polysilicon",

J. Appl. Phy. 57 (5), March 1985, pp. 1671-1675.

embodiments

1. Coating with polyvinyl alcohol directly on the glass pull

Alkali-free borosilicate glass of the AF 37 glass type from Schott with a thickness of 700 μm was coated with polyvinyl alcohol (Mowiol from Clariant; 10% dissolved in H ₂ 0) during the glass drawing process (down-draw). The glass transition temperature was approx. 80 ° C when the polyvinyl alcohol (viscosity 1100 mPas) was sprayed on both sides (top and bottom) and dried in an oven at 180 ° C for approx. 15 seconds during the on-line process. The tensile stress was 0.6 GPa, the layer thickness 10 μ. The surface strength of the same glass without coating was 512 MPa, while the glass with the above-mentioned coating had intrinsic strength measured at 2,350 MPa.

2. Coating of glass substrates with polyvinyl alcohol

Alkali-containing borosilicate glass (D 263 from Schott Displayglas GmbH), size 100 x 100 mm and thickness 0.4 mm, was made with a polyvinyl alcohol (Mowiol from Clariant, 16% in H ₂ 0) at room temperature using a centrifugal process (2000 min ^"1 , viscosity 250 mPas) and dried at 180 ° C. for 10 minutes. The layer thickness was 20 μm. With one-sided coating, the surface strength was 706 MPa (with a tensile stress of 0.2 GPa) and with two-sided coating (immersion process) 924 MPa (tensile stress 0.26 GPa) The uncoated samples had a surface strength of 579 MPa.

3. Coating of glass substrates with a silicone elastomer

Alkali-containing borosilicate glass (D 263 from Schott Displayglas GmbH, size 100 x 100 mm) with a thickness of 0.2 mm was obtained using a polydimethylsiloxane (Elastosil ^® from Wacker) using an immersion process

(Viscosity 70,000 mPas, drawing speed 50 cm / min) coated and at 180 ° C for 10 min. dried. The layer thickness was 40 μ, the tear strength of the polymer is 12 N / mm. The tensile stress was 0.14 GPa, while the surface strength was 722 MPa. The uncoated reference had a surface strength of 404 MPa.

4. Coating with a silicone resin

Alkali-containing borosilicate glass (D 263 from Schott Displayglas GmbH, format 100 x 100 mm) with a thickness of 0.1 mm was used

Alkylphenyl silicone resin Silres ^® (40% solution in xylene) from Wacker coated on one side with a centrifugal process (4000 min ^"1 , viscosity 60 mPas) and dried at 200 ° C. for 15 min. The layer thickness of the samples was 8.7 μm. The tensile stress was 0.21 GPa and the surface strength 733 MPa, while the uncoated samples had a ^'surface strength of 426 MPa.

5. Coating with a SiC _x O _y H _z plasma polymer

Using a low-pressure plasma process, borosilicate glass (D 263 from Schott Displayglas GmbH, glass thickness 0.4 mm, format 200 x 200 mm) was coated with hexamethlydisiloxane (HMDSO) as a monomer. A parallel plate reactor was used here, the lower electrode being connected to a high-frequency generator (13.56 MHz). The RF power applied to the electrode was 300 watts, the bias voltage also applied to this electrode was - 300 V. After 30 minutes, the was

Layer thickness 0.6 μ. An SiC _x O _y layer was produced which had a compressive stress of 0.3 GPa. The surface strength of the coated samples was 1420 MPa, while the uncoated samples had a surface strength of 579 MPa.

6. Coating with a SiC _x NH _z plasma polymer

Borosilicate glass (D 263 from Schott Displayglas GmbH, format 150 x 150 mm, 400 μm thick) was made of a 0.42 μm thin SiC _x N _y H _z layer using a high-frequency, low-pressure plasma in a parallel plate reactor

Tetramethylsilane (TMS) and nitrogen are generated. The deposition time was 20 minutes. The pressure was 0.11 mbar. A flow of 5 sccm (standard cubic centimeter per minute) TMS and 24 sccm nitrogen was set. The process pressure was 0.2 mbar. The compressive stress of the plasma polymer layer was 0.6 GPa. The surface strength was 1120 MPa, while the uncoated samples had a surface strength of 579 MPa.

7. D 263 glass / silicone resin / silicone elastomer composite

A glass film of size 100 x 100 mm of glass type D 263 (company lettering from Schott-pesag) is used as the glass substrate with a thickness of 100 μm, which is produced using the down-draw process. The strength of these glass substrates is approximately 470 MPa. The glass substrate is spun (5000 1 / min) with a

Methylphenyl silicone resin (product name Silres® from Wacker-Chemie GmbH, silicone resin / xylene solution mass ratio 1: 3) coated and then dried at 220 ° C. for 15 minutes in a forced air oven. The layer thickness is 4.5 μm, the tensile stress is 0.21 GPa and the surface strength is approx. 980 MPa. Since the silicone resins have a low chemical resistance i.a. compared to ketones, a second layer is applied. The silicone resin-coated glass substrates are coated with a silicone polymer film based on polydimethylsiloxane (product name Elastosil® from Wacker-Chemie GmbH, viscosity 70000 mPas) using a centrifugal process (5000 1 / min) and at

200 ° C dried in a forced air oven for 20 min. The layer thickness is 45 μ. The strength of the first coating was increased significantly, and the second coating improved the chemical resistance, in particular to ketones.

8. Coating with an amorphous silicon nitride layer using Plasma Enhanced Chemical Vapor Deposition (PECVD)

Substrate: AF45 0.7 mm x 400 x 400 mm from Schott display glass Plant: PI / PE-CVC reactor horizontal arrangement with plasma cage

Plasma excitation frequency: 13.56MHz

Plasma power: 40W

Temp .: T = 300 ° C

Precursor gases: SiH ₄ 65sccm, NH ₃ 280sccm

Carrier gases: N ₂ ^β OOsccm, H ₂ 178sccm

Process pressure: 890 bar

Layer thickness: ~ 450 nm

Layer stress: σ «- 345 ... -380 MPa

Surface strength without coating: σ ₀ «540 MPa Surface strength with coating: 'OS 950 MPa

Coating with a silicon oxide layer (SiO by sputtering (sputtering, PVD, phys. Vapor deposition)

Substrate: D263 0.4 x 400 x 400 mm ³ from Schott

Displayglas GmbH

System: Vertical in-line sputtering system with water-cooled magnetron cathode and

RF plasma generation

Source: 2 x linear water-cooled

Magnetron cathodes 488 mm wide with

Between the cooling zone

Fully oxidized quartz glass target

Plasma excitation frequency: 13.56 MHz plasma power: 2500W substrate temperature: 250 ° C carrier gases: Ar 40sccm, Kr 5sccm, 0 ₂ x sccm Driving speed: 0.1 m / min

Process pressure: 2.9 μbar

Layer thickness: ~ 280 nm

Layer tension: σ _s »- 180. .. -250 MPa

Surface strength without coating .; .: ^'"■" σ ₀ «579 MPa

Surface strength with coating: σ ' _n OS _ς «722 MPa

10. Coating of glass substrates with aluminum oxide (AlOJ by sputtering (sputtering, AVD Phys. Vapor Deposition)

Substrate: D263 0.4 x 400 x 400 mm ³ System: Vertical in-line sputtering system with water-cooled magnetron cathode and

RF plasma generation

Source: 2x linear magnetron cathode 488 mm wide

Al ₂ 0 ₃ target

Plasma excitation frequency: 13.56 MHz

Plasma power: 2x2500 W

Carrier gases: Ar 50sccm, Kr 5sccm, 0 ₂ 5sccm

Substrate temperature: 250 ° C

Driving speed: 0.15m / min

Process pressure: 3.2 ibar

Layer thickness: ~ 280 nm

Layer stress: σ _s «- 250 -330 MPa

Surface strength without coating: σ ₀ «579 MPa Surface strength with coating: 'os 754 MPa

11. Application of Cr by sputtering in the magnetron field

Substrate: AF 45 0.7 mm thickness 400 mm

Glass bandwidth from Schott display glass

System: Vertical Irt-Line sputtering system with water-cooled magnetron cathode and

DC plasma generation Source: Linear magnetron cathode 488 mm wide

Cr target

Plasma excitation frequency: 13.56 MHz Plasma power: 4 kW Carrier gases: Ar 40 sccm Process pressure: 2.6 μbar, pressure increase to

Plasma ignition to ~ 15 μbar

Layer thickness: ~ 400nm

Layer tension: 350 ... - 400 MPa

Surface strength without coating: 515 MPa Surface strength with coating: σ _os «1520 MPa

12. Coating of glass substrates with aluminum oxide (Al ₂ O ₃ ) by vapor deposition using the e-beam process

Substrate: D263 0.4 x 50 mm x 50 mm System: vacuum evaporation system with

planet suspension

Source: Balzers e-Beam on Al ₂ 0 ₃ , source distance

450 mm Residual gas pressure: 10 ^"5 mbar

Layer thickness: ~ 300nm

Layer stress: σ _s «225 -255 MPa (compressive stress)

Surface strength without coating: σ ₀ «404 MPa Surface strength with coating: - ^" σ _os «631 MPa

13. Coating of glass substrates with silicone resins

An alkali-containing borosilicate glass (D263 T from Schott Displayglas GmbH, format 100 x 100 mm) with a thickness of 0.1 mm was dissolved in xylene (55% solution) with a polysiloxane Silres® from Wacker (55% solution) and filtered. A 5% solution of F 100 (from Wacker) in xylene is then added for faster crosslinking of the polysiloxane solution and stirred with a magnetic stirrer. The glasses are coated with the polymer solution using a centrifugal process (1000 min ^'1 ) and dried at 230 ° C. for 60 min in a forced air oven. The layer thickness of the sample was 5.3 μm. The tensile stress was 0.19 GPa and the surface strength was 814 MPa, while the uncoated samples were one

Had a surface strength of 426 MPa.

14. Coating of glass substrates with an acrylate-epoxy polymer mixture

An alkali-containing borosilicate glass (D263 from Schott Displayglas GmbH, format 100 x 100 mm), 0.1 mm thick, was coated on both sides with a polymer mixture of polyacrylate and polyepoxide from Clariant (centrifugal process 800 min ^"1 ) and at 230 ° C. 30 min in a forced air oven. The layer thickness of the sample was 3.5 μm, the tensile stress 0.18 GPa and the surface strength 790 MPa, while the uncoated samples had a surface strength of 426 MPa.

15. Coating with polyurethane resin 15.1 2-component system

An alkali-containing borosilicate glass (D263 from Schott Displayglas GmbH, size 100 x 10 mm) with a thickness of 0.2 mm was coated with a polyurethane varnish (Desmodur / Desmophen, Bayer) using the spin-coat process. The viscosity of the resin system was adjusted with a non-polar solvent so that at a speed of 2000 rpm

Layer thickness of 5 μm resulted. The system was cured at 120 ° for 10 min. The tensile stress was 0.17 GPa and the surface strength was 683 MPa, while the uncoated samples had a surface strength of 404 MPa.

15.2 1-component system

An alkali-containing borosilicate glass (D263 from Schott Displayglas GmbH, size 300 x 400 mm) with a thickness of 0.2 mm was coated with the 1-component PU lacquer Coetrans (Coelan) by spraying. The paint was diluted with MIBK to a solids content of 20%. The paint was applied with an air atomizing nozzle (air pressure 2 bar), the layer thickness was 20 μm. The coating hardens at room temperature by reacting with atmospheric moisture within 1 hour. The samples had a tensile stress of 0.15 GPa and a surface strength of 679 MPa, while the uncoated samples had a surface strength of

404 MPa.

15.3 Coating with an aqueous PU system

An alkali-containing borosilicate glass (D263 from Schott Displayglas GmbH, size 100 x 100 mm) with a thickness of 0.2 mm was sprayed with the aqueous coating system hydroglaze (from Diegel) coated. The spray pressure was 3 bar, the nozzle diameter 0.8 mm. Depending on the application, layer thicknesses between 5 and 15 μm were obtained, the tensile stress being 0.18 GPa and the surface strength 752 MPa, while the uncoated samples had a surface strength of 404 MPa.

16. Coating with epoxy resin

An alkali-containing borosilicate glass (D263 from Schott Displayglas GmbH, size 100 x 100 mm) with a thickness of 0.2 mm was used with the 2 K

Epoxy Stycast 1269 A (Grace) coated in a spin-coat process (1500 s ^"1 ) and cured for 3 hours at 120 °. The layer thickness was 7.2 μm, the tensile stress 0.18 GPa and the surface strength 748 MPa ( Surface strength of the uncoated reference 404 MPa).

17. Coating with silicone elastomer (platinum-catalyzed - addition-crosslinking)

An alkali-containing borosilicate glass (D263 from Schott Displayglas GmbH, size 100 x 100 mm), 0.2 mm thick, was coated with an addition-crosslinking silicone using the spin-coat method (1300 s ^"1 ). The coating solution had the following formulation: 10 , 0 g vinyl siloxane 0.4 g crosslinker 0.1 g platinum catalyst

5.0 g ethyl acetate

After the spin coating, the coating was cured under an IR radiation field within 5 seconds and a layer thickness of 9.7 μm was achieved. The tensile stress of the coated samples was 0.19 GPa and the surface strength was 783 MPa, during the uncoated samples had a surface strength of 404 MPa.

18. Coating with UV-curing systems

An alkali-containing borosilicate glass (D263 from Schott Displayglas GmbH, size 100 x 100 mm) ^" 0.2 mm thick was coated with UV-curing coating systems using the spin-coat process (1300 s ^{" 1} ). The coating systems were based on the one hand on acrylate and on the other hand on epoxy. These coating systems were cured with a

Fusion lamp (lamp type H) and an output of 180 W / cm ² , which was passed over the coated samples at a speed of 6 m / min. The thickness of the acrylate coating was 7.6 μm (tensile stress 0.2 GPa, surface strength 658 MPa). The surface strength of the uncoated reference was 404 MPa.

Claims

claims

1. vitreous body with increased strength;

1.1 comprising a base body made of glass and at least one layer applied to it;

1.2 at least one layer is under compressive or tensile stress.

2. Glass body according to claim 1, characterized in that the compressive or tensile stress is in the range of 100 to 1000 MPa.

3. Glass body according to claim 1 or 2, characterized in that the layer material consists of organic or inorganic materials or of a mixture or a compound of organic and inorganic materials.

4. Glass body according to one of claims 1 to 3, characterized in that the layer under tension covers the surface of the glass body completely or partially.

5. Glass body according to one of claims 1 to 4, characterized in that the base body is in the form of flat glass, curved flat glass or a container glass.

6. Glass body according to claim 5, characterized in that the thickness of the base body is in the range of 10 to 1,500 microns.

7. vitreous body according to one of claims 1 to 6, characterized in that the base body is flexible and the thickness of the glass is in the range from 10 to 200 μm.

8. Glass body according to one of claims 1 to 7, characterized in that the glass body comprises two or more layers, at least one of the two or more layers being applied to protect the stressed layer or layers.

9. A method for producing a vitreous body according to one of the

Claims 1 to 8, characterized by the following process steps:

9.1 one or more layers is or are applied to the glass by dipping, spin coating, rolling on or spraying on organic polymers, inorganic materials or organically modified ceramic materials by means of sol-gel technology;

9.2 at least one layer is post-treated to set the required layer tension.

10. The method according to claim 9, characterized in that the layer consists of a polymer whose tear strength is at least 10N / mm.

11. The method according to claim 9, characterized in that the aftertreatment is carried out by thermal drying, electromagnetic radiation, UV treatment, UV / ozone treatment, corona treatment, electron beams, flame treatment.

12. The method according to any one of claims 1 to 8, characterized in that the coating is carried out in a vacuum using physical vapor deposition or sputtering processes.

13. The method according to any one of claims 1 to 8, characterized in that the coating is carried out by plasma-assisted deposition from the gas phase, by piasmapolymerization or by a plasma arc process.

14. The method according to claim 11, characterized in that

Metals, semiconductors, metal oxides, semiconductor oxides, metal nitrides, carbonitrides, oxynitrides, oxycarbides, semiconductor nitrides, carbonitrides, oxynitrides, oxycarbides or mixtures and compounds of these materials are used.

15. The method according to claim 12, characterized in that volatile metal compounds or volatile organic or organometallic compounds are used as starting materials.

16. The method according to any one of claims 11 to 14, characterized in that the layer voltage is generated by a bias by applying

DC voltage or AC voltage on the substrate is set.

17. The method according to any one of claims 1 to 15, characterized in that the coating and post-treatment takes place immediately after the hot molding.

18. Displays made with glass substrates according to claims 1 to

16th

19. Hard disks made with glass substrates according to claims 1 to 16.

20. Electrical circuit carrier made with glass substrates according to claims 1 to 16.

21. Tempered flat glass according to claims 1 to 8, characterized in that the coating fulfills further functional features on at least one side.

22. Tempered flat glass according to claim 17, characterized in that the coating acts on at least one side as an anti-reflective layer.

23. Tempered flat glass according to claim 17, characterized in that the coating acts on at least one side as a reflection or absorption layer.

24. Tempered flat glass according to claim 17, characterized in that the coating acts on at least one side as a diffusion barrier.

25. Tempered flat glass according to claim 17, characterized in that the coating acts on at least one side as a photosensitive layer.

26. Tempered flat glass according to claim 17, characterized in that the coating acts on at least one side as a polarizer.

7. Tempered flat glass according to claim 17, characterized in that the coating is used on at least one side for information storage.