Spacer for acoustically insulating glazing

Abstract

The present invention relates to a viscoelastic plastic interlayer (1) for a laminated glazing (2) having vibro-acoustic damping properties, the interlayer (1) comprising a vibro-acoustic damping layer (3), the damping layer (3) having a first thickness e 1, the sum of the first thickness e 1 and the second thickness e 2 being greater than or equal to 0.82 mm, and the ratio between the second thickness e 2 and the first thickness e 1 being greater than or equal to 5.05. FIG. 3

Description

Title of the invention: Spacer for acoustically insulating glazing Field of invention

[0001] The present invention relates to a viscoelastic interlayer for glazing, in particular for glazing of a dwelling. The present invention also relates to a method for designing this glazing. State of the art

[0002] It is known to use laminated glazing to manufacture a window for a home, enabling both the acoustic insulation of the home and the window to resist mechanical impacts, for example to prevent intrusions into the home. Document EP 0 842 767 describes, for example, such laminated glazing, comprising two sheets of glass joined by an interlayer having acoustic damping and / or low stiffness properties. However, the use of such an interlayer does not make it possible to obtain good performance both in terms of acoustic insulation and in terms of impact resistance.

[0003] For this purpose, it is known to increase the thickness of the interlayer so as to increase the acoustic performance and the resistance of the glazing to mechanical impacts. Document WO2020 / 152416 describes, for example, a glazing having an impact resistance of category P2A of the European standard EN 356. This impact resistance is permitted by increasing the thickness of the interlayer compared to known glazings, for a single-layer or multi-layer interlayer. However, in the case of a multi-layer interlayer, this document does not describe how to choose the thickness of each of the layers of the interlayer. In addition, this document does not describe the contributions of the different layers of an interlayer to the acoustic insulation on the one hand and to the resistance to mechanical impacts on the other hand. Statement of the invention

[0004] An aim of the invention is to provide an interlayer for a glazing having a resistance at least equal to the resistance of a P2A type glazing of the EN 356 standard, the glazing having improved sound insulation properties with respect to the sound insulation properties of a glazing comprising a single-layer interlayer, while limiting the quantity of raw materials necessary to produce the interlayer.

[0005] This aim is achieved, at least partially, within the framework of the present invention thanks to a viscoelastic interlayer for laminated glazing having vibro-acoustic damping properties, the interlayer comprising: - a vibro-acoustic damping layer, the damping layer having a first thickness e7, the vibro-acoustic damping layer being formed by a poly(vinyl butyral) (PVB) resin comprising a plasticizer, the mass content of plasticizer being strictly greater than 28.5%, - at least one skin layer, the skin layer or all of the skin layers having a second thickness e2, the skin layer being formed by a poly(vinyl butyral) (PVB) resin comprising a plasticizer, the mass content of plasticizer being less than 28.5%, - the sum of the first thickness e7 and the second thickness e2 being greater than or equal to 0.82 mm, - the ratio between the second thickness e2 and the first thickness e, being greater than or equal to 5.05.

[0006] The present invention is advantageously supplemented by the following characteristics, taken individually or in any of their technically possible combinations:

[0007] - the damping layer has a mass content of plasticizer between 28.5% excluded and 40%,

[0008] - the skin layer has a mass rate of plasticizer between 17% and 28.5%,

[0009] - the interlayer comprises two layers of skin, the vibro-damping layer acoustic being arranged between the two layers of skin,

[0010] - the first thickness e7 is between 0.10 mm and 0.15 mm and preferably between 0.12 mm and 0.14 mm,

[0011] - the second thickness e2 is between 0.64 mm and 0.75 mm and preferably between 0.69 mm and 0.72 mm,

[0012] - the ratio between the second thickness e2 and the first thickness e, is understood between 5.05 and 7.00, in particular between 5.05 and 6.00.

[0013] Another aspect of the invention is a laminated glazing having vibro-acoustic damping properties, comprising: - two sheets of glass, and - an interlayer according to one embodiment of the invention, the interlayer being arranged between the two sheets of glass.

[0014] The glazing advantageously has impact resistance greater than or equal to that of category P2A glazing according to European standard EN 356.

[0015] Each of the glass sheets advantageously has a thickness ev greater than 1.8 mm and in particular between 2.8 mm and 3.5 mm.

[0016] Each of the glass sheets advantageously has a thickness ev greater than 3 mm and in particular between 2.8 mm and 3.5 mm, and - the sum of the first thickness e7 and the second thickness e2 is greater than or equal to 0.82 mm, - the ratio between the second thickness e2 and the first thickness e2 is between 5.05 and 6.

[0017] Each of the glass sheets advantageously has a thickness ev of between 1.8 mm and 2.8 mm exclusive, and - the sum of the first thickness e7 and the second thickness e2 is greater than or equal to 0.85 mm, - the ratio between the second thickness e2 and the first thickness e2 is between 5.5 and 7.

[0018] Another aspect of the invention is a method of designing a glazing, the glazing being a glazing according to an embodiment of the invention, the glazing having a predetermined impact resistance, the method comprising steps of: - determination of the first thickness ej of the vibro-acoustic damping layer, then - determination of the second thickness e2 of the or all of the skin layers, from the first thickness ej and from the predetermined impact resistance.

[0019] Advantageously, the predetermined impact resistance is chosen so that the glazing belongs to a predetermined category according to the European standard EN 356, and in which the determination of the second thickness e2 is implemented from the predetermined category. Description of figures

[0020] Other characteristics, aims and advantages of the invention will emerge from the following description, which is purely illustrative and non-limiting, and which must be read in conjunction with the appended drawings in which:

[0021] [Fig.l] - [Fig.l] illustrates the acoustic insulation of different laminated glazings,

[0022] [Fig.2] - [Fig.2] illustrates the average perforation height with three balls of different laminated glazing,

[0023] [Fig.3] - [Fig.3] schematically illustrates a glazing in section according to a method of realization of the invention,

[0024] [Fig.4] - [Fig.4] illustrates a domain for the first thickness of a layer of core and the second thickness of skin layers of an interlayer according to one embodiment of the invention,

[0025] [Fig.5] - [Fig.5] schematically illustrates a method of designing a glazing according to one embodiment of the invention.

[0026] Throughout the figures, similar elements bear identical references. Definitions

[0027] Measurement of impact resistance

[0028] Compliance with category P2A of the EN 356 standard is measured by a ball drop test method (in English "ball drop test" or "hard body drop test") which consists of successively dropping three steel balls of 10 cm diameter and a mass of 4.1 kg from a certain height onto the glazing. To achieve category P2A, three samples of a glazing must withstand three successive ball drops from a height of 3 m.

[0029] From a statistical point of view, it is very difficult to draw significant conclusions on the performance of the tested glazing due to the limited number of samples (determination of a probability of failure at 3 m with only three samples).

[0030] A more robust method for assessing the performance of glazing according to the EN 356 standard has been developed by the applicant company. This method is the mean break height with three balls (MBH3). This method consists of dropping three balls successively from a certain height onto a glazing sample. If the sample passes the test without being punctured by the three balls, then another glazing of the same type is tested, dropping the three balls from a greater height corresponding to the height of the previous test plus a fixed increment value. If the sample does not pass the test, then another glazing of the same type is tested, dropping the three balls from a lower height corresponding to the height of the previous test minus a fixed increment value.By repeating this test, we converge and then oscillate around the average perforation height of the glazing by three balls. This height corresponds to the height at which half of the samples are perforated and the other half are not. We will preferably choose the starting height close to the average perforation height expected for the glazings tested, the fixed increment value (plus or minus) preferably being close to the standard deviation of a probability distribution examined by the test (probability of failure in the three-ball test as a function of the drop height of the balls). For a P2A performance test with laminated glazing, we will therefore choose a starting height of 3.6 m and an increment value of 0.3 m.A statistical treatment of this method shows that the mean perforation height and the associated standard deviation and the 95% confidence interval on the value of the mean perforation height can be defined and calculated (see Dixon W.J. Mood A., "A method for obtaining and analyzing sensitivity data", Journal of the American Statistical Association, 43, 1948). Once the mean perforation height and the associated standard deviation . obtained, we can then estimate whether the difference between the mean perforation height and the target height (for example 3 m for P2A level glazing) is large enough compared to the standard deviation of the distribution to ensure that the probability of failure at the target height is negligible. For example, if the target height is 3 m, the mean perforation height is 3.6 m and the standard deviation is 0.3 m, this means that the difference of 0.6 m is worth twice the standard deviation, and the probability of failure at 3 m is then 2.3% for a normal (Gaussian) distribution.

[0031] Poly(vinyl butyral) (PVB)

[0032] One layer of the interlayer is formed by a resin comprising poly(vinyl butyral) (PVB).

[0033] The person skilled in the art knows the following two types of PVB: standard PVB and acoustic PVB.

[0034] Standard PVB is historically the first PVB used for interlayers. In this document, the term "standard PVB" means a resin comprising PVB and comprising a plasticizer, the mass content of the plasticizer in the resin being less than 28.5%, preferably between 17% and 28.5%, in particular between 26.5% and 28.5%. The mass-average molar mass of co-polyvinyl butyral-polyvinyl alcohol may be between 100 and 250 g / mol. For example, the commercial product designated "RB41" from the Eastman company is a single-layer interlayer of standard PVB.

[0035] In the present invention, the term “acoustic PVB” means a resin comprising PVB and comprising a plasticizer, the mass content of the plasticizer in the resin being between 28.5% exclusive and 50%, preferably between 28.5% exclusive and 40%, in particular between 28.5% exclusive and 30.5%. For example, the commercial product designated “QS41” from the company Eastman is an interlayer comprising a core layer formed by an acoustic PVB. Detailed description of the invention

[0036] Effect of the thickness of an acoustic core layer of an interlayer

[0037] Referring to [Fig. 1], a glazing unit may comprise an interlayer and two glass sheets, each glass sheet having a thickness equal to 4 mm. The interlayer may be arranged between the two glass sheets. The interlayer may have a core layer of acoustic PVB and two skin layers of standard PVB, the core layer being arranged between the two skin layers.

[0038] The inventors have discovered that a variation in the thickness of all the skin layers only marginally affects the acoustic insulation of a glazing unit comprising the interlayer. Curve (a) of [Fig.l] illustrates the variation in the acoustic insulation of a glazing unit with frequency, the glazing unit comprising a known interlayer, the interlayer comprising an acoustic PVB core layer having a thickness equal to 0.1 mm and two standard PVB skin layers, the total thicknesses of the skin layers being equal to 0.70 mm. Curve (b) illustrates the variation of the sound insulation of a glazing unit with frequency, the glazing unit comprising an interlayer, the interlayer comprising an acoustic PVB core layer having a thickness equal to 0.1 mm and two standard PVB skin layers, the total thicknesses of the skin layers being equal to 0.35 mm. Curve (c) illustrates the variation of the sound insulation of a glazing unit with frequency, the glazing unit comprising an interlayer, the interlayer comprising an acoustic PVB core layer having a thickness equal to 0.1 mm and two standard PVB skin layers, the total thicknesses of the skin layers being equal to 1.4 mm.Curve (d) illustrates the variation of the sound insulation of a glazing unit with frequency, the glazing unit comprising an interlayer, the interlayer comprising an acoustic PVB core layer having a thickness equal to 0.1 mm and two standard PVB skin layers, the total thicknesses of the skin layers being equal to 2.1 mm. Curve (e) illustrates the variation of the sound insulation of a glazing unit with frequency, the glazing unit comprising an interlayer, the interlayer comprising an acoustic PVB core layer having a thickness equal to 0.1 mm and two standard PVB skin layers, the total thicknesses of the skin layers being equal to 2.8 mm.

[0039] [Table 1] below describes sound reduction indices calculated from the simulations illustrated by [Fig.l]. The indices are calculated following the NF EN ISO 717-1:2013-05 standard. The weighted sound reduction index is noted Rw. The weighted sound reduction index adapted to a spectrum related to human activities and air traffic noise is noted RA. The weighted sound reduction index adapted to a spectrum related to road traffic is noted RAtr. The indices are calculated for different total thicknesses of skin layers.

[0040] [Tables 1] Total thickness of skin layers (mm) 0.35 0.7 1.4 2.1 2.8 Rw (dB) 37 37 37 37 38 Ra (dB) 36 36 36 37 37 RA,Tr(dB) 34 34 35 35 35

[0041] Thus, the thickness of the core layer of the interlayer can be chosen independently of the other thicknesses, since the thickness of the other layers of the interlayer will only marginally affect the acoustic insulation of the glazing.

[0042] Effect of the total thickness of the interlayer

[0043] With reference to [Fig. 2], the values ​​of the MBH3 test, described above, are measured for glazing units comprising an interlayer. The glazing unit comprises two sheets of glass each having an equal thickness and an interlayer. In particular, curve (f) illustrates a glazing unit in which each sheet of glass has a thickness equal to 3 mm and curve (g) illustrates a glazing unit in which each sheet of glass has a thickness equal to 2 mm. The interlayer comprises a core layer having a thickness equal to 0.13 mm. The total thickness of the skin layers varies depending on the glazing units tested.

[0044] The inventors have discovered that the value of the MBH3 test is linear with respect to the total thickness of the interlayer and in particular with respect to the total thickness of the skin layers for a constant core layer thickness, as illustrated by [Fig.2]. Thus, from the chart constructed in [Fig.2], it is possible to predetermine a total minimum thickness of the interlayer, i.e. the sum of the thickness of the core layer and the thickness of all the skin layers, to exhibit impact resistance according to a predetermined category. Since the thickness of the core layer can be predetermined as seen previously, it is possible to calculate the minimum and sufficient thickness of all the skin layers for the glazing to exhibit impact resistance according to a predetermined category.

[0045] With reference to [Fig.2], the thicknesses of the interlayer layers for a glazing meeting the criteria of category P2A of standard EN 356 are sought. In order for the glazing not to be perforated by impacts, the difference between the height H and the value of the MBH3 test must be greater than several times the standard deviation of the heights tested in the MBH sequence, preferably greater than three times the standard deviation, which makes it possible, for a Gaussian statistic, to ensure a failure rate of less than 0.15%. For the glazing illustrated by [Fig.2], the standard deviation is approximately equal to 0.35 m for a total thickness of the interlayer equal to 0.76 mm. Curve (f) illustrates the MBH3 for a glazing in which each of the glass sheets has a thickness equal to 3 mm. Curve (g) illustrates the MBH3 for glazing in which each of the glass sheets has a thickness equal to 2 mm.

[0046] Interleaf 1

[0047] With reference to [Fig. 3], one aspect of the invention is a viscoelastic interlayer 1 for a laminated glazing 2 having vibro-acoustic damping properties.

[0048] The interlayer 1 comprises a vibro-acoustic damping layer 3. The damping layer 3 has a first thickness ej. The vibro-acoustic damping layer 3 is formed by a poly(vinyl butyral) (PVB) resin comprising a plasticizer, the mass content of plasticizer being strictly greater than 28.5%. In particular, the damping layer 3 is made of PVB acoustic.

[0049] The interlayer 1 comprises at least one skin layer 4. The skin layer 4 or all of the skin layers 4 have a second thickness e2. The skin layer 4 is formed by a poly(vinyl butyral) (PVB) resin comprising a plasticizer. The mass content of plasticizer is less than 28.5%. In particular, the skin layer 4 is made of standard PVB.

[0050] The sum of the first thickness e7 and the second thickness e2 is greater than or equal to 0.82 mm. In the case where the interlayer comprises only a core layer and one or more skin layers, the thickness of the interlayer etot is greater than or equal to 0.82 mm. The ratio between the second thickness e2 and the first thickness e2 is greater than or equal to 5.05. Thus, the interlayer is suitable for the manufacture of glazing having impact resistance characteristics meeting at least category P2A of the EN356 standard, while limiting the quantity of material used to manufacture the core layer, maintaining sound insulation characteristics equivalent to known glazings and limiting the total quantity of material used to manufacture the interlayer.In particular, this effect is achieved for glazing comprising glass sheets, each glass sheet having a thickness ev greater than 3 mm, in particular between 3 mm and 3.5 mm. In particular, the thickness etot is chosen so that the difference between an average perforation height with three balls greater than or equal to 3 m (MBH3) and 3 m is greater than three times the standard deviation of the height distribution. Thus, the probability of a glazing breakage caused by an impact is approximately zero. The value of such a standard deviation is approximately 0.35 m, which makes it possible to calculate the predefined condition on the thickness etot.

[0051] [Fig.4] illustrates the domain (comprising peas in [Fig.4]) in which the first thickness ej and the second thickness e2 can be chosen.

[0052] The interlayer 1 may comprise two skin layers 4. The vibro-acoustic damping layer 3 may be arranged between the two skin layers 4. Thus, it is possible to limit the first thickness ej so as to respect the relationship defined above relating to the ratio between the first thickness ej and the second thickness e2, while facilitating the manufacture of the interlayer (by preventing a roll of PVB from sticking to itself). Alternatively, the interlayer 1 may comprise two layers, including a core layer and a skin layer. Alternatively, the interlayer 1 may comprise a core layer and at least three skin layers. Skin layers may be superimposed so as to choose the second thickness from several films for the manufacture of the skin layer having the same thickness.

[0053] The first thickness e7 may be between 0.10 mm and 0.15 mm and preferably between 0.12 mm and 0.14 mm. Thus, the sound insulation of the glazing 1 can be maximized while limiting the amount of material used to manufacture the core layer. Indeed, as illustrated by [Fig.l], an increase in the second thickness e2 has only a negligible impact with regard to the sound insulation of the glazing.

[0054] The second thickness e2 may be greater than 0.64 mm, in particular between 0.64 mm and 0.75 mm, and preferably between 0.69 mm and 0.72 mm. The ratio between the second thickness e2 and the first thickness e may be between 5.05 and 7.00, in particular between 5.05 and 6.00. Thus, the interlayer is suitable for manufacturing a glazing 1 having mechanical impact resistance properties at least equal to a glazing of category P2A of the EN 356 standard, while making it possible to reduce, for an equal interlayer thickness, the thickness of the core layer.

[0055] Glazing 2

[0056] With reference to [Fig. 3], another aspect of the invention is laminated glazing 2 having vibro-acoustic damping properties. The glazing 2 comprises two glass sheets 5 and an interlayer 1. The interlayer 1 is arranged between the two glass sheets 5.

[0057] Glazing 2 may have an impact resistance greater than or equal to that of category P2A glazing according to European standard EN 356. In other words, glazing 2 may have an average perforation height with three balls greater than or equal to 3 m. Thus, glazing 2 may delay or prevent unwanted intrusion into a home.

[0058] Each glass sheet may be a monolithic glass sheet. The monolithic glass sheet may be formed by at least one material selected from a structural polymer, preferably poly(methyl methacrylate), polycarbonate, structural polyurethane, soda-lime glass, aluminosilicate glass, borosilicate glass. The glass sheet may be thermally toughened or chemically toughened.

[0059] Each glass sheet 5 may have a thickness ev greater than 1.8 mm and in particular between 1.8 mm and 2.8 mm excluded. Thus, by choosing the thickness range of a predefined glass sheet, and in particular for a sum of the first thickness ejet of the second thickness e2 greater than or equal to 0.85 mm, and a ratio between the second thickness e2 and the first thickness ej of between 5.05 and 7.00, the glazing 2 has resistance properties at least equal to that of a glazing of category P2A of the EN 356 standard, while limiting the thickness of the glass sheet used with respect to known glazings having the same resistance.

[0060] Each glass sheet 5 may have a thickness ev greater than 2.8 mm and in particular between 2.8 mm and 3.5 mm excluded. Thus, by choosing the range thickness of a predefined glass sheet, and in particular for a sum of the first thickness e7 and the second thickness e2 greater than or equal to 0.82 mm, and a ratio between the second thickness e2 and the first thickness e, between 5.05 and 6.00.1e glazing 2 has resistance properties at least equal to that of a glazing of category P2A of standard EN 356, while limiting the thickness of the glass sheet used with respect to known glazings having the same resistance.

[0061] Glazing design method 2

[0062] With reference to [Fig. 5], another aspect of the invention is a method 6 for designing a glazing 2. The glazing 2 has a predetermined impact resistance. It is for example possible to choose an impact resistance according to a category of the EN 356 standard. It is also possible to choose an impact resistance by predetermining an average perforation height with three balls, according to the aforementioned method.

[0063] The method 6 comprises a step 61 of determining the first thickness e2 of the vibro-acoustic damping layer. The method 6 comprises a subsequent step 62 of determining the second thickness e2 of the or all of the skin layers, from the first thickness e2 and from the predetermined impact resistance.

[0064] When implementing the method 6, the predetermined impact resistance can be chosen so that the glazing 2 belongs to a predetermined category according to the European standard EN 356. The determination of the second thickness e2 can be implemented from the predetermined category. Thus, it is not necessary to determine the first thickness ej with regard to the desired mechanical resistance properties of the glazing 2, which makes it possible to simplify its design.

Claims

Claims

1. Viscoelastic interlayer for laminated glazing having vibro-acoustic damping properties, the interlayer comprising: - a vibro-acoustic damping layer, the damping layer having a first thickness eh, the vibro-acoustic damping layer being formed by a poly(vinyl butyral) (PVB) resin comprising a plasticizer, the mass content of plasticizer being strictly greater than 28.5%, - at least one skin layer, the skin layer or all of the skin layers having a second thickness e2, the skin layer being formed by a poly(vinyl butyral) (PVB) resin comprising a plasticizer, the mass content of plasticizer being less than 28.5%, - the sum of the first thickness e7 and the second thickness e2 being greater than or equal to 0.82 mm, - the ratio between the second thickness e2 and the first thickness e2 being greater than or equal to 5.

05.

2. Interlayer (1) according to the preceding claim, in which the damping layer (3) has a mass content of plasticizer of between 28.5% exclusive and 40%.

3. Interlayer (1) according to claim 1 or 2, in which the skin layer (4) has a mass content of plasticizer of between 17% and 28.5%,

4. Interlayer (1) according to one of the preceding claims, the interlayer (1) comprising two skin layers (4), the vibro-acoustic damping layer (3) being arranged between the two skin layers (4).

5. Interlayer (1) according to one of the preceding claims, in which the first thickness e7 is between 0.10 mm and 0.15 mm, preferably between 0.12 mm and 0.14 mm.

6. Interlayer (1) according to one of the preceding claims, in which the second thickness e2 is between 0.64 mm and 0.75 mm, preferably between 0.69 mm and 0.72 mm.

7. Interlayer (1) according to one of the preceding claims, in which the ratio between the second thickness e2 and the first thickness e, is between 5.05 and 7.

00.

8. Laminated glazing (2) having vibro-acoustic damping properties, comprising: - two sheets of glass (5), and - an interlayer (1) according to one of the preceding claims, the interlayer (1) being arranged between the two sheets of glass (5).

9. Glazing (2) according to the preceding claim, having an impact resistance greater than or equal to that of a P2A category glazing according to European standard EN 356.

10. Glazing (2) according to claim 8 or 9, in which each of the glass sheets (5) has a thickness ev greater than 1.8 mm.

11. Glazing (2) according to claim 10, in which each of the glass sheets has a thickness ev greater than 3 mm, and in which: - the sum of the first thickness e7 and the second thickness e2 is greater than or equal to 0.82 mm, - the ratio between the second thickness e2 and the first thickness ej is between 5.05 and 6.

12. Glazing (2) according to claim 10, in which each of the glass sheets has a thickness ev of between 1.8 mm and 2.8 mm exclusive, and in which: - the sum of the first thickness e7 and the second thickness e2 is greater than or equal to 0.85 mm, - the ratio between the second thickness e2 and the first thickness e2 is between 5.5 and 7.

13. Method (6) for designing a glazing (2), the glazing (2) being in accordance with a glazing as defined in one of claims 8 to 10, the glazing (2) having a predetermined impact resistance, the method comprising steps of: - determining (61) the first thickness e2 of the vibro-acoustic damping layer, then - determining (62) the second thickness e2 of the or all of the skin layers, from the first thickness e2 and from the predetermined impact resistance.

14. Method (6) for designing a glazing (2) according to the preceding claim, in which the predetermined impact resistance is chosen so that the glazing (2) belongs to a predetermined category according to the European standard EN 356, and in which the determination of the second thickness e2 is implemented from the predetermined category.