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 interlayers, at least one surface of one of the interlayers comprising a bird repellent pattern disposed between the two interlayers, and at least one interlayer comprising an ionomer.

Description

[Technical field]

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

[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 glass sheets bonded together by an interlayer. Such membranes are often made from plasticizer-containing polyvinyl acetals, such as polyvinyl butyral (PVB). Partially neutralized ethylene acid copolymers, called "ionomers," have also been used as interlayers to make laminated safety glass, as disclosed, for example, in U.S. Pat. No. 3,404,134 and WO 2019 / 027865.

[0004] Therefore, a possible solution is to modify the surface of the 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 a first and a second interlayer, characterized in that at least one surface of the first interlayer is provided with an anti-bird pattern facing the second interlayer, the first interlayer comprising an ionomer, preferably the anti-bird pattern being printed or coated on at least one surface of the first interlayer.

[0008] In other words, the bird-repellent pattern is sandwiched between the first and second 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-blocking agents 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 color vision and can see light in the ultraviolet range, so bird-repellent patterns can be made on the first intermediate layer with ultraviolet absorbers or ultraviolet reflectors, in which case these patterns are 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 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] Also preferred are 1,2,3,4-butanetetracarboxylic acid, 1,2,3,4-tetrakis(2,2,6,6-tetramethyl-4-piperidinyl) ester (64022-61-3) or butanedicarboxylic acid, 1,4-dimethyl ester, polymer with 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol (65447-77-0).

[0016] The transmittance for light in the range of 380 to 750 nm is measured in accordance with JIS R 3106.

[0017] 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.

[0018] Surprisingly, it has also been found that laminates 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 laminate appears transparent, provide 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 laminates with a yellowness index db of less than 3, preferably less than 2.5, more preferably less than 2 in areas that do not contain a bird-repellent pattern.

[0019] Yellowness is determined by the transmittance of the film at 430 nm in ColorQuest XE at Hunterlab 2° / C setting in accordance with EN410.

[0020] Preferably, the thickness of the first and second intermediate layers is independently from 450 to 2500 μm, more preferably from 600 to 1000 μm, and most preferably from 700 to 900 μm.

[0021] Alternatively, if one intermediate layer has the thickness described above, the other intermediate layer may be significantly thinner. In this embodiment, the thinner intermediate layer is less than 100 μm, preferably 10 to 100 μm, more preferably 15 to 75 μm, most preferably 20 to 50 μm, specifically about 25 μm.

[0022] Preferably, both the first and second intermediate layers comprise an ionomer.

[0023] The term "ionomer" as used herein generally refers to a polymer containing ionic groups that are carboxylates, such as ammonium carboxylates, alkali metal carboxylates, alkaline earth metal carboxylates, transition metal carboxylates and / or combinations of such carboxylates. Such polymers are generally prepared by partially or completely neutralizing the carboxylic acid groups of a precursor or parent polymer, which is an acid copolymer as defined herein, for example by reaction with a base. An alkali metal ionomer as used herein is a sodium ionomer, such as a copolymer of ethylene and methacrylic acid, in which all or a portion of the carboxylic acid groups of the copolymerized methacrylic acid units are neutralized, with substantially all of the neutralized carboxylic acid groups being in the form of sodium carboxylate.

[0024] In the ethylene-α,β-unsaturated carboxylic acid copolymer serving as the base polymer, the content of the constitutional units derived from the α,β-unsaturated carboxylic acid is typically 2% by mass or more or 5% by mass or more (based on the total mass of the copolymer).Furthermore, the content of the constitutional units derived from the α,β-unsaturated carboxylic acid is typically 30% by mass or less (based on the total mass of the copolymer).

[0025] Examples of α,β-unsaturated carboxylic acids that make up the ionomer include, but are not limited to, acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, and mixtures of two or more thereof. In one embodiment, the α,β-ethylenically unsaturated carboxylic acid is selected from acrylic acid, methacrylic acid, and mixtures thereof. In another embodiment, the α,β-ethylenically unsaturated carboxylic acid is methacrylic acid.

[0026] To obtain ionomers, the ethylene acid copolymer is partially neutralized by reaction with one or more bases. Examples of suitable procedures for neutralizing ethylene acid copolymers are described in US Patent Nos. 3,404,134 and 6,518,365. After neutralization, from about 1%, or from about 10%, or from about 15%, or from about 20%, to about 90%, or to about 60%, or to about 55%, or more than about 30%, of the hydrogen atoms of the carboxylic acid groups present in the ethylene acid copolymer are replaced with cations.

[0027] Preferably, the ionomers according to the present invention are sodium neutralized ethylene-α,β-unsaturated carboxylic acid copolymers.

[0028] In addition, the film may contain further additives such as residual amounts of water, plasticizers, oxidation inhibitors, adhesion promoters or regulators, optical brighteners or fluorescent 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 regulator.

[0029] However, preferably the intermediate layer does not contain a plasticizer.

[0030] A preferred adhesion promoter is a silane. Silanes suitable for use according to the present invention are dialkoxysilanes. In one embodiment, each alkoxy group contains 1 to 3 carbon atoms. Suitable examples include diethoxydimethylsilane, diethoxy(methyl)vinylsilane, 1,3-diethoxy-1,1,3,3-tetramethyldisiloxane, dimethoxydimethylsilane, dimethoxymethylvinylsilane, methyldiethoxysilane, diisopropyldimethoxysilane, dicyclopentyldimethoxysilane, γ-aminopropyl-N-cyclohexylmethyldimethoxysilane, 3-aminopropylmethyldimethoxysilane, N-phenyl-3-aminopropylmethyldimethoxysilane, N-phenyl-3-aminopropylmethyldimethoxysilane, NP-(aminoethyl)-γ-aminopropylmethyldimethoxysilane, and 3-glycidoxypropylmethyldiethoxysilane.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] The present invention also relates to a method for producing the laminated glass described above.

[0035] The first and second intermediate layers may be any conventional ionomer sheet, such as, for example, the Trosifol® SentryGlas® series of products commercially available from, for example, Kuraray Europe GmbH, having a thickness of 0.76 mm.

[0036] The bird repellent pattern can be coated or printed onto at least one surface of the first intermediate layer. The printed or coated layer typically contains an inorganic or organic pigment that should not dissolve in the polymer matrix.

[0037] 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".

[0038] Water-based printing inks are preferred over organic solvent-based printing inks because they do not swell or dissolve the interlayer and / or cause defects in the interlayer.

[0039] 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.

[0040] 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.

[0041] The first and second interlayers can then be joined together such that the bird-repellent pattern contacts a major surface of the second interlayer, and then the interlayer stack so produced can be laminated between two glass panes to produce laminated glass.

[0042] 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 glass for reducing or preventing bird strikes, comprising at least two glass panes and at least a first interlayer and a second interlayer, 1. A laminated glass, wherein at least one surface of the first interlayer comprises a bird repellent pattern facing the second interlayer, the first interlayer comprises an ionomer, and the yellowness index db of the laminated glass in areas not including the bird repellent pattern is less than 2 as determined at 430 nm in ColorQuest XE at a Hunterlab 2° / C setting in accordance with EN 410.

2. 10. The laminated glass of claim 1, wherein the bird repellent pattern is printed or coated onto the at least one surface of the first interlayer.

3. 3. The laminated glass according to claim 1, wherein the bird-repellent pattern has a transmittance of less than 5% for light in the range of 380 to 750 nm, 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 a range of 380 to 750 nm, measured in accordance with JIS R 3106, and contains an ultraviolet absorber or an ultraviolet reflector.

5. 3. The laminated glass according to claim 1, wherein the ionomer is an ethylene-α,β-unsaturated carboxylic acid copolymer neutralized with sodium.

6. 3. The laminated glass according to claim 1, wherein the bird-repellent pattern is a dot pattern.

7. 3. The laminated glass of claim 1, wherein the first interlayer comprises a dialkoxysilane.

8. 3. The laminated glass of claim 1 or 2, wherein the second interlayer comprises an ionomer.

9. 3. The laminated glass according to claim 1, wherein at least the first interlayer and / or the second interlayer does not contain a plasticizer.

10. 3. The laminated glass according to claim 1, wherein the ionomer resin of the first intermediate layer and the second intermediate layer is an ethylene-α,β-unsaturated carboxylic acid copolymer neutralized with sodium.

11. A glass window comprising the laminated glass of claim 1 or 2 and a third glass sheet separated from the first glass sheet or the second glass sheet by air.