Bulletproof laminated glass

Abstract

The invention relates to a laminated glass comprising a first glass layer, at least one second glass layer spaced from the first glass layer, and a resin layer provided between the first and second glass layers. The laminated glass contains, by weight, 71-75% SiO2, 0.5-1.5% AI2O3, 6-12% CaO, 4-7% MgO, 11-15% Na2O, and is adjusted to provide resistance at BR-7 NS levels according to the EN1063 standard.

Description

[0001] BULLETPROOF LAMINATED GLASS

[0002] TECHNICAL FIELD

[0003] The present invention relates to laminated glass consisting of at least two thin glass sheets, particularly designed to be used as laminated glass for the vehicles, especially for a windshield.

[0004] STATE OF THE ART

[0005] Commercially available transparent glass-based shield generally consists of multiple layers of glass and polymer combined to form a relatively thick composite. The resulting composite must remain transparent without optical distortion, while also providing maximum protection against bullet and fragment impacts with minimal weight and cost. In particular, laminated glass structures are required to locally limit the damage caused by a bullet, thus maximizing the remaining field of view and providing protection against multiple impacts.

[0006] Laminated glass is generally used in the automotive, aerospace, or construction industries due to its advantage of being "safety" glass. It is typically consist of at least two glass sheets bonded together by an interlayer made of plastic, usually polyvinyl butyral (PVB). Traditionally, the glass used for windshields is designed asymmetrically and consists of two sheets of sodium-calcium-silicate glass, with the outer sheet being thicker than the inner one. To increase the mechanical durability of such glass, the component glass sheets are tempered, creating a compressive region on the surface and a tensile region at the center.

[0007] EP2909148B1 publication relates to a laminated glass comprising at least one outer glass sheet, an inner glass sheet, and a polymer interlayer positioned between the two glass sheets. In EP2909148B1 , the inner glass sheet has a maximum thickness of 1.5 mm. The outer glass sheet is a glass sheet with a chemical composition different from that of the inner sheet, and the difference between the Tp1 and Tp2 temperatures is less than 80°C. Tp1 is defined as the arithmetic mean of the upper annealing temperature and softening temperature of the outer glass sheet, and Tp2 is defined as the arithmetic mean of the upper annealing temperature and softening temperature of the inner glass sheet. BRIEF DESCRIPTION OF THE INVENTION

[0008] The object of the invention is to provide a bulletproof glass structure.

[0009] In order to achieve above objective, the invention relates to a laminated glass comprising a first glass layer, at least one second glass layer spaced from the first glass layer, and a resin layer provided between the first and second glass layers. The laminated glass, in terms of the weight ratio of the first and second glass layers, contains 71-75% SiO2, 0.5-1 .5% AI2O3, 6-12% CaO, 4-7% MgO, 11-15% Na2O, and is adjusted to meet BR-7 NS level resistance according to the EN1063 standard. In this way, the glass layers, with a composition that reduces the bullet’s kinetic energy upon impact, and the resin layer, which absorbs the bullet’s kinetic energy and prevents the spread of mechanical damage, ensure that bullets fired from various weapons are contained within the laminated glass system, preventing them from reaching the protected side at the rear of the system or causing injuries from glass fragments during an attack.

[0010] In a preferred embodiment of the invention, the SiO2 weight ratio is in the range of 71% to 73%. Thus, SiO2, acting as the main oxide and network former, increases the durability of the glass, enhancing its ballistic resistance. Additionally, the melting temperature is increased. SiO2 is sourced primarily from kaolin and sand, both of which contain high silica content.

[0011] In a preferred embodiment of the invention, the CaO weight ratio is in the range of 8% to 10%. In this way, the use of calcium oxide increases the mechanical durability of the laminated glass, making it more resistant to impacts and other physical effects.

[0012] In a preferred embodiment of the invention, the MgO weight ratio is in the range of 4% to 5%. Thus, the use of magnesium oxide increases the mechanical durability of the laminated glass.

[0013] In a preferred embodiment of the invention, the Na2O weight ratio is in the range of 13% to 14%. In this way, the use of sodium oxide lowers the melting point, making the glass production process more manageable and enabling the creation of glass that can be processed at lower temperatures.

[0014] In a preferred embodiment of the invention, the K2O weight ratio is in the range of 0.07% to 0.12%. Thus, the use of potassium oxide reduces the viscosity and crystallization tendency of the laminated glass, facilitating its melting. In a preferred embodiment of the invention, the Fe2O3 weight ratio is in the range of 0.06% to 0.3%. Thus, the use of ferric oxide strengthens the mechanical durability of the glass.

[0015] In a preferred embodiment of the invention, the TiO2 weight ratio is in the range of 0.049% to 0.073%. Thus, the use of titanium dioxide increases the laminated glass’s resistance to alkalis and acids.

[0016] In a preferred embodiment of the invention, the SO3 weight ratio is in the range of 0.21% to 0.22%. Thus, SO3 is added as a refining agent to the glass batch.

[0017] In a preferred embodiment of the invention, the total glass thickness is in the range of 62-64 mm. In this way, it is made suitable for vehicle use and meets the relevant standards.

[0018] In a preferred embodiment of the invention, the total glass weight is in the range of 140 to 145 kg / m2. In this way, it is made suitable for vehicle use and meets the relevant standards.

[0019] In a preferred embodiment of the invention, the resin layer contains polyvinyl butyral (PVB). In this way, the bullet’s kinetic energy is absorbed, and the spread of mechanical damage is prevented.

[0020] In a preferred embodiment of the invention, the bottommost layer contains polycarbonate. Thus, the formation of fragments from the shattering laminated glass upon impact is prevented.

[0021] In a preferred embodiment of the invention, the layer adjacent to the bottommost layer contains thermoplastic polyurethane. In this way, the spread of mechanical damage is prevented.

[0022] In a preferred application of the invention, the glass layers are cut, the resin layer is provided between the two glass layers, and the layers are combined with thermoplastic polyurethane (TPU) between the seventh glass layer and the polycarbonate layer, followed by the assembled glass layers being placed in an autoclave at a temperature of 120°C and a pressure of 6 bars for 8 hours to laminate them. Thus, the glass layers used in the intermediate layers can be used untreated, semi-tempered, or chemically tempered. BRIEF DESCRIPTION OF THE FIGURES

[0023] Figure 1 is a schematic representation of the bulletproof laminated glass.

[0024] DETAILED DESCRIPTION OF THE INVENTION

[0025] In this detailed description, the development subject to the invention is explained with references to examples in a manner that does not limit the scope of the invention, but rather serves to better illustrate the concept.

[0026] In Figure 1 , the bulletproof laminated glass is shown schematically. The bulletproof laminated glass consists of a first glass layer (10), a second glass layer (20), a third glass layer (30), a fourth glass layer (40), a fifth glass layer (50), a sixth glass layer (60), a seventh glass layer (70), and a resin layer (80) provided between them. Below the seventh glass layer (70), there is a polycarbonate layer (90), with a resin layer (80) positioned between them. The glass layers (10, 20, 30, 40, 50, 60, 70) contain, by weight, 71-75% SiO2, especially 71-73%, 0.5- 1.5% AI2O3, 6-12% CaO, especially 8-10%, 4-7% MgO, especially 4-5%, 13-14% Na2O, and other additives.

[0027] The table above shows the percentage by weight of the materials used in the glass composition. In Example 1 , the glass layers (10, 20, 30, 40, 50, 60, 70) contain, by weight, 71.76% SiO2, 0.95% AI2O3, 8.54% CaO, 4.39% MgO, 13.74% Na2O, 0.07% K2O, 0.30% Fe2O3, 0.049% TiO2, and 0.21 % SO3. The resin layer (80), which contains polymeric polyvinyl butyral (PVB) and thermoplastic polyurethane (TPU) and is positioned between the glass layers (10, 20, 30, 40, 50, 60, 70), and a polycarbonate layer (90) below the seventh glass layer (70) make the glass suitable for vehicle use. The total thickness of this glass composition is reduced to 62-64 mm, preferably 63 mm, and the total weight is reduced to 140-145 kg / m2, preferably 144 kg / m2. The resulting bulletproof laminated glass, combined with transparent polymeric resin layers (80), exhibits BR-7 NS level resistance according to the EN1063 standard.

[0028] In Example 2, the glass layers (10, 20, 30, 40, 50, 60, 70) contain, by weight, 72.01 % SiO2, 0.53% AI2O3, 9.22% CaO, 4.46% MgO, 13.30% Na2O, 0.12% K2O, 0.067% Fe2O3, 0.073% TiO2, and 0.22% SO3. This glass composition also creates a bulletproof glass suitable for vehicle use, with the same thickness and weight range as Example 1.

[0029] The production method of laminated glass designed according to the composition values shown in Example 1 or Example 2 involves cutting the glass layers (10, 20, 30, 40, 50, 60, 70) into dimensions of 50 cm x 50 cm, combining the resin layer (80), which contains PVB, between two glass layers, and assembling the seventh glass layer (70) and the polycarbonate layer (90) with TPU in between. The assembled glass layers are laminated in an autoclave at 120°C and 6 bars of pressure for 8 hours. The glass layers used in the intermediate layers can be untreated, semi-tempered, or chemically tempered. The first glass layer (10) is produced with a thickness of 10 mm, the second, third, fourth, and fifth glass layers (20, 30, 40, 50) are produced with a thickness of 8 mm, the sixth and seventh glass layers (60, 70) are produced with a thickness of 6 mm. The resin layer (80) has a thickness of 0.76 mm, the resin layer (80) containing thermoplastic polyurethane between the seventh glass layer (70) and the polycarbonate layer (90) has a thickness of 1.27 mm, and the polycarbonate layer has a thickness of 3 mm. Firing tests were conducted to test the structural strength of the produced laminated glass. The firing tests were carried out according to the EN 1063 standard using 7.62 x 51 mm AP (armor-piercing) standard ammunition. Three shots were fired at speeds of 828.50 m / s, 819.09 m / s, and 821.85 m / s. An aluminum witness plate was placed behind the laminated glass system to verify whether any penetration or fragmentation occurred. No penetration or fragmentation was observed after the tests.

[0030] REFERENCE NUMBERS

[0031] 10 First Glass Layer

[0032] 20 Second Glass Layer

[0033] 30 Third Glass Layer

[0034] 40 Fourth Glass Layer 50 Fifth Glass Layer 60 Sixth Glass Layer 70 Seventh Glass Layer 80 Resin Layer 90 Polycarbonate Layer

Claims

CLAIMS1. A laminated glass comprising a first glass layer, at least one second glass layer spaced from the first glass layer, and a resin layer provided between the first and second glass layers, characterized in that, by weight, the first and second glass layers contain:- 71-75% SiO2,- 0.5-1 .5% AI2O3,- 6-12% CaO,- 4-7% MgO,- 11-15% Na2O, and the thickness of the laminated glass is adjusted to provide resistance at BR-7 NS levels according to the EN1063 standard.

2. The laminated glass according to claim 1 , wherein the SiO2 weight ratio is in the range of 71% to 73%.

3. The multilayer laminated glass according to any of the preceding claims, wherein the CaO weight ratio is in the range of 8% to 10%.

4. The multilayer laminated glass according to any of the preceding claims, wherein the MgO weight ratio is in the range of 4% to 5%.

5. The multilayer laminated glass according to any of the preceding claims, wherein the Na2O weight ratio is in the range of 13% to 14%.

6. The multilayer laminated glass according to any of the preceding claims, wherein the K2O weight ratio is in the range of 0.07% to 0.12%.

7. The multilayer laminated glass according to any of the preceding claims, wherein the Fe2O3 weight ratio is in the range of 0.06% to 0.3%.

8. The multilayer laminated glass according to any of the preceding claims, wherein the TiO2 weight ratio is in the range of 0.049% to 0.073%.

9. The multilayer laminated glass according to any of the preceding claims, wherein the SO3 weight ratio is in the range of 0.21% to 0.22%.

10. The laminated glass according to any of the preceding claims, wherein the total glass thickness is in the range of 62-64 mm.

11. The multilayer laminated glass composition according to any of the preceding claims, wherein the total glass weight is in the range of 140 to 145 kg / m2.

12. The multilayer laminated glass according to any of the preceding claims, wherein the resin layer contains polyvinyl butyral (PVB).

13. The multilayer laminated glass according to any of the preceding claims, wherein the bottommost layer contains polycarbonate.

14. The multilayer laminated glass according to any of the preceding claims, wherein the layer adjacent to the bottommost layer contains thermoplastic polyurethane.

15. A method for producing a multilayer laminated glass according to any of the preceding claims, comprising the steps of cutting the glass layers (10, 20, 30, 40, 50, 60, 70), providing a resin layer (80) between two glass layers, assembling the seventh glass layer (70) and polycarbonate layer (90) with thermoplastic polyurethane (TPU) in between, and laminating the assembled glass layers (10, 20, 30, 40, 50, 60, 70) in an autoclave at 120°C and 6 bars for 8 hours.

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