LAMINATED GLASS WITH THIN INNER PANE AND SOUNDPROOFING THERMOPLASTIC INTERMEDIATE LAYER

Abstract

A vehicular laminated glass for separating a vehicle interior from an external environment is presented. The laminated glass includes inner and outer panes made of glass and having respective thicknesses of less than or equal to 0.4 mm, and greater than or equal to 1.5 mm, and an acoustically damping intermediate layer that bonds the inner pane to the outer pane. According to one aspect, the acoustically damping intermediate layer has two outer polymeric layers between which an inner polymeric layer is positioned, the outer polymeric layers having lower elasticity or plasticity than the inner polymeric layer. According to another aspect, the inner polymeric layer has a thickness of 0.05 mm to 0.40 mm, each of the outer polymeric layers have a thickness of 0.20 mm to 0.60 mm, and the total thickness of the acoustically damping intermediate layer is at least 0.70 mm.

Claims

1.-14. (canceled)

15. A vehicular laminated glass for separating a vehicle interior from an external environment, the vehicular laminated glass, comprising: an inner pane made of glass, the inner pane having a thickness of less than or equal to 0.4 mm; an outer pane made of glass, the outer pane having a thickness of greater than or equal to 1.5 mm; and an acoustically damping intermediate layer that bonds the inner pane to the outer pane, wherein the acoustically damping intermediate layer comprises at least two outer polymeric layers and an inner polymeric layer positioned therebetween, the at least two outer polymeric layers have lower elasticity or plasticity than the inner polymeric layer, the inner polymeric layer has a thickness of 0.05 mm to 0.40 mm, the at least two outer polymeric layers each have a thickness of 0.20 mm to 0.60 mm, and the total thickness of the acoustically damping intermediate layer is at least 0.70 mm.

16. The vehicular laminated glass according to claim 15, wherein: a damping factor ?.sub.1 of a first mode and a damping factor ?.sub.2 of a second mode of the vehicular laminated glass measured according to a mechanical impedance measurement (MIM) per ISO 16940 at a temperature of 20? C., with the vehicular laminated glass having: i) a surface area of 25 mm?300 mm; ii) a thickness of 2.1 mm for each of the inner pane and the outer pane between which the acoustically damping intermediate layer is laminated, are ?.sub.1?0.20 and ?.sub.2?0.25.

17. The vehicular laminated glass according to claim 16, wherein ?.sub.1?0.25 and ?.sub.2?0.30.

18. The vehicular laminated glass according to claim 16, wherein ?.sub.1?0.25 and ?.sub.2?0.35.

19. The vehicular laminated glass according to claim 15, wherein the inner pane has a thickness of 0.1 mm to 0.4 mm, preferably approx. 0.3 mm.

20. The vehicular laminated glass according to claim 15, wherein the inner pane has a thickness substantially equal to 0.3 mm.

21. The vehicular laminated glass according to claim 15, wherein the outer pane has a thickness of 1.5 mm to 2.6 mm.

22. The vehicular laminated glass according to claim 15, wherein the outer pane has a thickness of 1.6 mm to 2.1 mm.

23. The vehicular laminated glass according to claim 15, wherein the outer pane has a thickness substantially equal to 1.8 mm.

24. The vehicular laminated glass according to claim 15, wherein the at least two outer polymeric layers and the inner polymeric layer contain at least one of: a) polyvinyl butyral (PVB), b) ethylene vinyl acetate (EVA), c) polyurethane (PU), and d) mixtures or copolymers or derivatives of one or more of a)-c).

25. The vehicular laminated glass according to claim 24, wherein d) comprises at least one of: d1) polyvinyl butyral (PVB); d2) polyvinyl butyral (PVB); and d3) plasticizers.

26. The vehicular laminated glass according to claim 15, wherein the inner polymeric layer has a thickness of 0.07 mm to 0.30 mm.

27. The vehicular laminated glass according to claim 15, wherein the inner polymeric layer has a thickness of 0.10 mm to 0.20 mm.

28. The vehicular laminated glass according to claim 15, wherein the outer polymeric layers each have a thickness of 0.30 mm to 0.40 mm.

29. The vehicular laminated glass according to claim 15, wherein the inner pane is a chemically tempered pane.

30. The vehicular laminated glass according to claim 29, wherein the inner pane contains aluminosilicate glass.

31. The vehicular laminated glass according to claim 29, wherein the inner pane contains from 55 wt.-% to 72 wt.-% silicon oxide (SiO.sub.2), from 5 wt.-% to 10 wt.-% aluminum oxide (Al.sub.2O.sub.3), from 10 wt.-% to 15 wt.-% sodium oxide (Na.sub.2O), from 7 wt.-% to 12 wt.-% potassium oxide (K.sub.2O), and from 6 wt.-% to 11 wt.-% magnesium oxide (MgO).

32. The vehicular laminated glass according to claim 15, wherein the inner pane is a non-prestressed pane and contains borosilicate glass.

33. The vehicular laminated glass according to claim 15, wherein the outer pane is a non-prestressed pane.

34. The vehicular laminated glass according to claim 15, wherein the outer pane contains soda lime glass.

35. A method for producing a vehicular laminated glass, the method comprising: arranging, respectively in a sequential order, an inner pane, an acoustically damping intermediate layer, and an outer pane, areally atop one another; and bonding the inner pane and the outer pane to one another by lamination, wherein the inner pane is made of glass and has a thickness of less than or equal to 0.4 mm, wherein the outer pane is made of glass and has a thickness greater than or equal to 1.5 mm, wherein the acoustically damping intermediate layer comprises at least two outer polymeric layers and an inner polymeric layer positioned therebetween, wherein the at least two outer polymeric layers have lower elasticity or plasticity than the inner polymeric layer, wherein the inner polymeric layer has a thickness of 0.05 mm to 0.40 mm, wherein the at least two outer polymeric layers each have a thickness of 0.20 mm to 0.60 mm, and wherein the total thickness of the acoustically damping intermediate layer is at least 0.70 mm.

36. A method comprising: using of the vehicular laminated glass of claim 15 in a motor vehicle, including in one or more of: a) a windshield of a passenger car, b) a side window of a passenger car, c) a rear window of a passenger car, and d) a roof panel of a passenger car.

Description

[0060] They depict:

[0061] FIG. 1 a cross-section through an embodiment of the laminated glass according to the invention,

[0062] FIG. 2 a flowchart of an embodiment of the method according to the invention.

[0063] FIG. 1 depicts a laminated glass according to the invention, which is made of an inner pane 1 and an outer pane 2, which are bonded to one another via an acoustically damping intermediate layer 3. The acoustically damping intermediate layer 3 is formed from an inner polymeric layer 3.2 and two outer polymeric layers 3.1, wherein the outer polymeric layers 3.1 are in each case immediately adjacent the inner pane 1 or outer pane 2 areally and the inner polymeric layer 3.2 is situated between the outer polymeric layers 3.1 and is immediately adjacent them areally. The outer polymeric layers 3.1 are in each case made of PVB with a thickness of 0.35 mm. The inner polymeric layer 3.2 is made of PVB with a thickness of 0.15 mm. The elasticity of the inner polymeric layer 3.2 is higher than the elasticity of the outer polymeric layers 3.1. The inner pane 1 is chemically tempered, whereas the outer pane is not tempered. The laminated glass is provided as a windshield of a motor vehicle. The laminated glass is, as is customary for motor vehicle windshields, three-dimensionally curved. This means that the pane has curvature in multiple spatial directions, in particular in a horizontal and vertical direction. However, for the sake of simplicity, the laminated glass is schematically depicted flat in the figure.

[0064] The laminated glass according to the invention has, due to its low glass thicknesses, a very low weight. However, it is characterized by high break resistance and stone impact resistance. The laminated glass meets, in particular, the high safety requirements for laminated glazings in the automotive sector, such that, it can be used, for example, as a windshield. Through the additional stabilization of the composite pane by means of the acoustically damping intermediate layer, it is, in particular, possible to use an extremely thin inner pane for the vehicular panes. This result was unexpected and surprising for the person skilled in the art.

[0065] Alternatively, the inner pane 1 can, for example, also be made of non-tempered borosilicate glass. It has been demonstrated that even with such a glass combination (outer pane 1.5 mm, non-tempered soda lime glass; inner pane 0.4 mm non-tempered borosilicate glass), very good results in terms of stability and break resistance can be obtained.

[0066] FIG. 2 depicts a flowchart of an embodiment of the method according to the invention for producing a laminated glass according to the invention. An inner pane 1 and an outer pane 2 are provided in a planar starting state. The inner pane 1 and the outer pane 2 are subjected together to a bending process and congruently bent into their final three-dimensional shape.

[0067] Optionally, the inner pane 1 is chemically tempered after bending. To that end, the inner pane 1 is cooled slowly after bending in order to avoid thermal stresses. A suitable cooling rate is, for example, 0.1? C./sec. The inner pane 1 is subsequently treated for a period of a few hours, for example, 4 hours, at a temperature of 460? C. with a melt of potassium nitrate and chemically tempered thereby. The treatment effects a diffusion-driven exchange of sodium ions by larger potassium ions over the surface of the glass. Surface compressive stresses are thus generated. The inner pane 1 is subsequently cooled and then washed with sulfuric acid to remove residues of the potassium nitrate.

[0068] Subsequently, an acoustically damping intermediate layer 3 is arranged between the inner pane 1 and the outer pane 2. The stack made up of the inner pane 1, intermediate layer 3, and outer pane 2 is bonded in a conventional manner by lamination, for example, by a vacuum bag method.

LIST OF REFERENCE CHARACTERS

[0069] (1) inner pane [0070] (2) outer pane [0071] (3) acoustically damping intermediate layer [0072] (3.1) outer polymeric layer having lower elasticity [0073] (3.2) inner polymeric layer having higher elasticity