Laminated glass with bird-proof pattern

Abstract

The present invention is directed to a laminated glazing comprising two glass sheets laminated together by at least two thermoplastic interlayers, at least one surface of one of the interlayers comprising a bird-repellent pattern disposed between the two thermoplastic interlayers, the at least one thermoplastic interlayer comprising polyvinyl acetal.

Description

[Technical field]

[0001] The present invention is directed to a laminated glazing comprising two glass sheets laminated together by at least two thermoplastic interlayers, at least one surface of one of the interlayers comprising a bird-repellent pattern disposed between the two thermoplastic interlayers, the at least one thermoplastic interlayer comprising polyvinyl acetal.

[0002] Collisions into windows are one of the biggest threats to birds, as birds do not perceive the window glass as an obstacle. Efforts have been made to develop bird-safe glass by turning the window glass into an obstacle that birds can see and avoid. Such glass usually has bird-proof patterns, i.e., visual markers, on the entire surface of the glass to distort the reflection of the surrounding elements. Such patterns are generally printed directly onto the surface of one of the glass panes, for example by enamel printing. However, such printing techniques are not very flexible and are quite costly in the manufacturing process. In addition, such printing techniques can degrade the quality of the glass, as enamel printing requires high temperatures.

[0003] Laminated glass usually consists of two panes of glass bonded together by a thermoplastic interlayer, often made from a plasticizer-containing polyvinyl acetal such as polyvinyl butyral (PVB).

[0004] Therefore, a possible solution is to modify the surface of a thermoplastic interlayer with an anti-bird pattern and then laminate it between two glass sheets. However, the inventors have now found that this approach has various drawbacks. The anti-bird pattern printed or coated on the surface of the interlayer using ink can interfere with the glass surface, resulting in problems with the adhesion between the interlayer and the glass. This can compromise the safety of the laminated glass.

[0005] Furthermore, it has surprisingly been found that when the pattern is in direct contact with the glass surface, the optical quality is reduced, especially in terms of the sharp boundaries of the individual objects that make up the bird-repellent pattern. This reduction in optical quality inevitably leads to a reduction in the economic value of the window produced.

[0006] The problem addressed by the present invention was therefore to provide laminated glass with an anti-bird pattern that has improved stability, optical quality, durability and / or processability. These and other problems have been solved by the present invention.

[0007] Thus, a first aspect of the invention relates to a laminated glazing for reducing or preventing bird strikes comprising at least two glass sheets and at least first and second thermoplastic interlayers, characterized in that at least one surface of the first thermoplastic interlayer is provided with an anti-bird pattern facing the second thermoplastic interlayer, the first thermoplastic interlayer comprising polyvinyl acetal, preferably the anti-bird pattern being printed or coated on at least one surface of the first thermoplastic interlayer.

[0008] In other words, the bird-repellent pattern is sandwiched between the first and second thermoplastic interlayers, so that the pattern does not come into direct contact with the glass surface of one of the two glass panes. This feature significantly improves the adhesion of the interlayer to the glass panes, and therefore the safety of the laminated glass. Furthermore, the optical quality of the individual features of the pattern is significantly improved. In addition, the use of UV filters present in the two interlayers on either side of the pattern can reduce fading or degradation of the pattern due to exposure to sunlight.

[0009] Also, preferably, the bird-proof pattern has a transmittance of less than 5% for light in the range of 380 to 750 nm. In this embodiment, the bird-proof pattern can have any color. However, the bird-proof pattern is preferably black or gray.

[0010] Alternatively, the bird repellent pattern has a transmittance of more than 50% for light in the range of 380 to 750 nm and includes an ultraviolet absorbing agent or an ultraviolet reflecting agent.

[0011] Unlike humans, many birds have tetrachromatic vision and can see light in the ultraviolet range, so bird repellent patterns can be present on the first thermoplastic intermediate layer with UV absorbers or UV reflectors, which are then visible to birds but perceived as transparent to the human eye.

[0012] Examples of suitable UV reflectors include tin oxide or titanium oxide, which can be deposited on the surface of the first thermoplastic intermediate layer by any conventional thin film deposition, coating or printing technique.

[0013] Examples of suitable UV absorbers include benzotriazole-based compounds, benzophenone-based compounds, triazine-based compounds, benzoate-based compounds, malonate-based compounds or oxalic acid anilide-based compounds.

[0014] More preferably, the ultraviolet absorber is a benzotriazole-based ultraviolet absorber such as 2-(5-methyl-2-hydroxyphenyl)benzotriazole, 2-[2-hydroxy-3,5-bis(α,ω-dimethylbenzyl)phenyl]-2H-benzotriazole, 2-(3,5-di-t-butyl-2-hydroxyphenyl)benzotriazole, 2-(5-chloro-2-benzotriazolyl)-6-tert-butyl-p-cresol, 2-(3-t-butyl-5-methyl-2-hydroxyphenyl)-5-chlorobenzotriazole, 2-(3,5-di-t-butyl-5-methyl-2-hydroxyphenyl)-5-chlorobenzotriazole, 2-(3,5-di-t-amyl-2-hydroxyphenyl)benzotriazole, and 2-(2′-hydroxy-5′-t-octylphenyl)benzotriazole. or 2,2,6,6-tetramethyl-4-piperidyl benzoate, bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)-2-(3,5-di-t-butyl-4-hydroxybenzyl)-2-n-butylmalonate, and 4-(3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy)-1-( hindered amine-based UV absorbers such as 2-(3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy)ethyl)-2,2,6,6-tetramethylpiperidine; or benzoate-based UV absorbers such as 2,4-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate and hexadecyl-3,5-di-t-butyl-4-hydroxybenzoate. Most preferably, the UV absorber has a hydroxyphenylbenzotriazole structural unit. 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol is particularly preferred.

[0015] The transmittance for light in the range of 380 to 750 nm is measured in accordance with JIS R 3106.

[0016] The bird repellent pattern can have any shape or motif. Preferably, the bird repellent pattern includes a plurality of different elements, such as dots, lines or grids. More preferably, the different elements have a major dimension between 1 mm and 10 mm. Most preferably, the bird repellent pattern is a dot pattern.

[0017] Surprisingly, it has also been found that laminated glass with a low yellowness index db in areas that do not contain a bird-repellent pattern, i.e. areas where there is no coating or printing and the laminated glass appears transparent, gives particularly advantageous results in terms of bird protection. It is believed that these highly transparent areas increase the contrast with the printed / coated areas on the first interlayer, so that birds can more easily detect the printed / coated areas. Thus, a preferred embodiment of the present invention relates to laminated glass in which the yellowness index db of the laminated glass in areas that do not contain a bird-repellent pattern is less than 3, preferably less than 2.5, more preferably less than 2, and particularly preferably less than 1.0.

[0018] Yellowness is determined by the transmittance of the film at 430 nm in ColorQuest XE at Hunterlab 2° / C setting in accordance with EN410.

[0019] Preferably, the thickness of the first and second thermoplastic intermediate layers is independently from 450 to 2500 μm, more preferably from 600 to 1000 μm, and most preferably from 700 to 900 μm.

[0020] Alternatively, if one thermoplastic interlayer has a thickness as described above, the other thermoplastic interlayer may be significantly thinner, in this embodiment, the thinner thermoplastic interlayer is less than 100 μm, preferably 10-100 μm, more preferably 15-75 μm, most preferably 20-50 μm, specifically about 25 μm.

[0021] Preferably, both the first and second thermoplastic intermediate layers comprise polyvinyl acetal.

[0022] The membranes can include polyvinyl acetals each having a different polyvinyl alcohol content, degree of acetalization, residual acetate content, ethylene percentage, molecular weight, and / or different chain lengths of the aldehyde in the acetal group.

[0023] In particular, the aldehydes used to prepare the polyvinyl acetals can be linear or branched (i.e., "n" or "iso") containing from 2 to 10 carbon atoms, resulting in the corresponding linear or branched acetal groups, which are correspondingly called "polyvinyl (iso)acetals" or "polyvinyl (n)acetals."

[0024] Polyvinyl butyral is particularly preferred.

[0025] The polyvinyl acetals used have a proportion of polyvinyl acetate groups of 0.1 to 20 mol %, preferably 0.5 to 3 mol % or 5 to 8 mol %.

[0026] The polyvinyl alcohol content of the polyvinyl acetal may be 6 to 26 mass%, 8 to 24 mass%, 10 to 22 mass%, 12 to 21 mass%, 14 to 20 mass%, or 16 to 19 mass%, and preferably 16 to 21 mass% or 10 to 16 mass%.

[0027] The vinyl alcohol content and vinyl acetate content of the polyvinyl acetals are specified in accordance with DIN ISO 3681 (acetate content) and DIN ISO 53240 (PVA content).

[0028] Preferably, the first and second thermoplastic intermediate layers contain at least 16% by weight of plasticizer, for example 16.1 to 36.0% by weight, preferably 22.0 to 32.0% by weight, in particular 26.0 to 30.0% by weight.

[0029] Alternatively, one of the two interlayers may contain less than 18% by weight (e.g., 17.9% by weight), less than 12% by weight, less than 8% by weight, less than 6% by weight, less than 4% by weight, less than 3% by weight, less than 2% by weight, less than 1% by weight of plasticizer, or even no plasticizer (0.0% by weight), when the other interlayer contains a large amount of plasticizer within the ranges set forth herein above.

[0030] Suitable plasticizers are: esters of polyhydric aliphatic or aromatic acids, for example dialkyl adipates, such as dihexyl adipate, dioctyl adipate, hexylcyclohexyl adipate, mixtures of heptyl adipate and nonyl adipate, diisononyl adipate, heptylnonyl adipate, and esters of adipic acid with cycloaliphatic ester alcohols or with ether compound-containing ester alcohols, dialkyl sebacates, for example dibutyl sebacate, and esters of sebacic acid with cycloaliphatic ester alcohols or with ether compound-containing ester alcohols, esters of phthalic acid, for example butyl benzyl phthalate or bis-2-butoxyethyl phthalate, esters or ethers of polyhydric aliphatic or aromatic alcohols or oligoether glycols having one or more unbranched or branched aliphatic or aromatic substituents, such as esters of glycerol, diglycol, triglycol or tetraglycol with linear or branched aliphatic or cycloaliphatic carboxylic acids; examples of the latter group include diethylene glycol-bis-(2-ethylhexanoate), triethylene glycol-bis-(2-ethylhexanoate), triethylene glycol-bis-(2-ethylbutanoate), tetraethylene glycol-bis-n-heptanoate, triethylene glycol-bis-n-heptanoate, triethylene glycol-bis-n-hexanoate, tetraethylene glycol dimethyl ether and / or dipropylene glycol benzoate, phosphoric acid esters with aliphatic or aromatic ester alcohols, such as tris(2-ethylhexyl) phosphate (TOF), triethyl phosphate, diphenyl-2-ethylhexyl phosphate and / or tricresyl phosphate, Esters of citric acid, succinic acid, and / or fumaric acid can be selected from the group:

[0031] In addition, the film may contain further additives such as residual amounts of water, oxidation inhibitors, adhesion modifiers, optical brighteners or additives, stabilizers, colorants, processing aids, organic nanoparticles, pyrogenic silicic acid, and / or surface-active substances. In particular, the film may contain 0.001 to 0.1 wt. % of an alkali salt and / or an alkaline earth salt of a carboxylic acid as an adhesion modifier.

[0032] The film may further include one or more of the UV absorbers mentioned above in the bulk of the material in addition to or in place of the UV absorbers used to form the bird repellent pattern on the surface of the intermediate layer.

[0033] The laminated glass of the present invention can be used in a variety of architectural applications, such as windows, structural building panels in buildings or stadiums, decorative building panels, indoor or outdoor staircases or platforms, skylights in roadways or walkways, railings, curtain walls, floors, balconies, columns, skylights, and privacy screens.

[0034] In a second aspect, the present invention relates to a glass window comprising the laminated glass according to the present invention and further a third glass sheet separated by air from the first or second glass sheet. Such glass windows are generally used for the purpose of improving thermal and / or sound insulation.

[0035] The present invention also relates to a method for producing the laminated glass described above.

[0036] The first and second thermoplastic intermediate layers may be any conventional polyvinyl butyral sheet, such as, for example, 0.76 mm thick, such as the Trosifol® series of products commercially available from, for example, Kuraray Europe GmbH.

[0037] The bird repellent pattern can be coated or printed onto at least one surface of the first thermoplastic intermediate layer. The printed or coated layer typically contains an inorganic or organic pigment that should not dissolve in the polymer matrix.

[0038] Any suitable pigment may be used, including carbon black, iron oxide, polyaniline, perylene, or spinel pigments. The pigment may be dispersed in a carrier fluid, such as water, alcohol, or a mixture of alcohol and water. Additionally, a binder may be present, such as polyvinyl alcohol, polyvinyl butyral, polyvinylpyrrolidone, polyacrylate, polyurethane, or polystyrene acrylate. Such printing compositions are hereinafter referred to as "printing inks" or simply "inks".

[0039] Water-based printing inks are preferred over organic solvent-based printing inks as they do not swell or dissolve the film and / or cause film defects.

[0040] Printing inks can be applied by techniques commonly known in the printing industry, such as offset, gravure, flexography, and screen printing, and are usually followed by a drying step.

[0041] The dry film thickness of the printed part is between 1 and 50 μm depending on the printing technique and the required opacity. Typically, the dry film thickness is between 10 and 30 μm. The total dry film thickness may be obtained by superposing several ink layers from successive printing or coating processes.

[0042] Thereafter, the first and second thermoplastic interlayers can be joined together such that the bird deterrent pattern contacts a major surface of the second thermoplastic interlayer, and then the interlayer stack so produced can be laminated between two glass panes to produce a laminated glass.

[0043] Vacuum laminators can be used. These consist of a chamber that can be heated and evacuated, in which the laminated glass can be laminated within 30-60 minutes. Reduced pressures of 0.01-300 mbar and temperatures of 100-200 ° C, especially 130-160 ° C, have proven their worth in practice.

Claims

1. 1. A laminated glazing for reducing or preventing bird strikes comprising at least two glass sheets and at least a first thermoplastic interlayer and a second thermoplastic interlayer, 1. A laminated glass, comprising: at least one surface of the first thermoplastic interlayer comprising a bird repellent pattern facing the second thermoplastic interlayer; and the first thermoplastic interlayer comprises polyvinyl acetal; and the yellowness index db of the laminated glass in areas not including the bird repellent pattern is less than 1.0 as determined by film transmittance at 430 nm in ColorQuest XE at Hunterlab 2° / C setting in accordance with EN 410.

2. 2. The laminated glazing of claim 1, wherein the bird deterrent pattern is printed or coated onto the at least one surface of the first thermoplastic interlayer.

3. 3. The laminated glass according to claim 1, wherein the bird-proof pattern has a transmittance of less than 5% for light in the range of 380 to 750 nm, as measured in accordance with JIS R 3106.

4. 3. The laminated glass according to claim 1 or 2, wherein the laminated glass in an area not including the bird-repellent pattern has a transmittance of more than 50% for light in the range of 380 to 750 nm, as measured in accordance with JIS R 3106, and contains an ultraviolet absorber or an ultraviolet reflector.

5. 5. The laminated glass according to claim 1, wherein the bird-repellent pattern comprises a plurality of different elements.

6. The laminated glazing of claim 5, wherein the distinct elements have a major dimension of from 1 mm to 10 mm.

7. 7. The laminated glass according to claim 5, wherein the bird-repellent pattern is a dot pattern.

8. 8. The laminated glass of claim 1, wherein the second thermoplastic interlayer comprises polyvinyl acetal.

9. 9. The laminated glass according to claim 1 , wherein at least the first thermoplastic interlayer or the second thermoplastic interlayer comprises at least one plasticizer in an amount of more than 16% by weight before lamination.

10. 10. The laminated glass of claim 1, wherein the polyvinyl acetal of the first thermoplastic interlayer and the second thermoplastic interlayer is polyvinyl butyral (PVB).

11. 11. A glass window comprising the laminated glass of any one of claims 1 to 10 and further comprising a third glass sheet separated from the first glass sheet or the second glass sheet by air.

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