Method for influencing strength of glass

Abstract

A method of reducing strength of a first glass sheet is described. A portion of the first major surface of the first glass sheet is treated with a first powder to reduce the strength of the first glass sheet. The first powder includes particles comprising aluminosilicate glass. Glass sheets treated using such a method can be used to make laminated glazing in which a first glass sheet is laminated to a sheet of glazing material using an interlayer structure comprising at least one sheet of bonded interlayer material. The strength of the first glass sheet may be reduced before or after lamination to the sheet of glazing material.

Description

Technical Field

[0001] This invention relates to a method for reducing the strength of glass sheets and a method for manufacturing laminated window glass comprising glass sheets having reduced strength. Such laminated window glass can be used as windows in automobiles, particularly as windshields for vehicles. Background Technology

[0002] Conventional laminated window glass for automotive windshields consists of two layers of soda-lime silicate glass bonded together from polyvinyl butyral (PVB) sheets. Typically, each glass sheet is 2.1 mm thick, and the PVB sheet is usually 0.76 mm thick.

[0003] As is well known in the art, stacked car windshields offer improved safety benefits to vehicle drivers. However, vehicle manufacturers are also addressing vehicle safety issues in the event of a forward collision with a pedestrian.

[0004] In the event of a collision with a pedestrian, the pedestrian's head may strike the vehicle's windshield, causing further injury.

[0005] WO2013181505A1 describes a glass laminate comprising at least one chemically strengthened glass sheet with a thickness not exceeding 2.0 mm and a polymer interlayer between the glass sheets. Defects are generated in the surface of one of the glass sheets to weaken the glass laminate in the event of an impact event on a first side of the laminate, while maintaining the strength of the laminate in the event of an impact on an opposite second side of the laminate.

[0006] EP2062862A1 describes a glass sheet stack structure produced by stacking at least three glass sheets in an interlayer between two adjacent glass sheets, each glass sheet having a thickness of less than 1 mm.

[0007] WO2019245819A1 describes a glass laminate structure with controlled fracture for pedestrian safety.

[0008] WO202115654A1 describes a laminated glass for a vehicle that has undergone a strength flattening process, which may include the use of powder with an average particle diameter of 10 nm to 100 μm.

[0009] Polishing materials, such as glass, to improve their optical quality is well known in the art.

[0010] Cerium oxide (or cerium dioxide) has been used for polishing glass surfaces for many years, see, for example, US2,383,500.

[0011] US2,597,182 describes a smoothing technique used between grinding and polishing steps to smooth glass blanks. A mixture of rouge and pumice is used as the abrasive. This grinding, smoothing, and polishing process was widely used before the development of the float glass process.

[0012] US2012 / 0094578A1 describes a heterogeneous aggregated composite structure having multiple first particles (typically nanoparticles) on the surface of a second particle (typically a micron-sized particle) used in polishing compositions for removing stains and polishing glass. The first particles comprise cerium oxide, and the second particles comprise silicon oxide, aluminum oxide, and / or zirconium oxide. In the heterogeneous aggregate, the first particles are held on the surface of the second particles by electrostatic forces.

[0013] WO2003 / 091351A2 describes an unexpanded perlite polishing composition. The composition comprises a base material of unexpanded perlite grains having a selected grain size distribution, said grains undergoing grain breakage upon application of an abrasive force to the base material. The selected grain size distribution comprises relatively large-volume unexpanded perlite grains having a (d90) grain size in the range of about 101 to about 229 μm. The base material, in response to an abrasive force applied thereto during polishing, causes the continuous breakage of the unexpanded perlite grains to produce a final polishing composition with a sufficiently low level of abrasiveness under said abrasive force, making it suitable for polishing. A composition and method thereof for polishing acrylic dentures and CRT tube surfaces using the unexpanded perlite polishing composition are also described.

[0014] Polishing compositions for unexpanded perlite ore and their uses are also described in US2003 / 0203337A1 and US2003 / 0224702A1.

[0015] The perlite polishing compositions described in WO2003 / 091351A2, US2003 / 0203337A1 and US2003 / 0224702A1 have an initial selected grain size distribution that varies with use because unexpanded perlite grains continue to break during polishing under abrasive force. Summary of the Invention

[0016] The purpose of this invention is to provide a method for reducing the strength of glass sheets that can be used to manufacture laminated window glass for vehicle windshields, thereby reducing the risk of serious pedestrian injury in the event of a collision between the vehicle and a pedestrian.

[0017] Therefore, a first aspect of the present invention provides a method for reducing the strength of a first glass sheet having a first primary surface and a second opposing primary surface; the method includes a processing step of treating a portion of the first primary surface of the first glass sheet with a first powder to reduce the strength of the first glass sheet; wherein the first powder comprises particles of aluminosilicate glass.

[0018] Preferably, the aluminosilicate glass includes pumice. The pumice is aluminosilicate glass because the composition contains silicon dioxide (SiO2) and aluminum oxide (Al2O3).

[0019] Preferably, the aluminosilicate glass comprises basalt. Basalt is an aluminosilicate glass because the composition contains silicon dioxide (SiO2) and aluminum oxide (Al2O3). Other pulverized igneous rocks may also be used to form the first powder.

[0020] Preferably, the aluminosilicate glass has a composition comprising (by weight) 40-75% SiO2, 5-20% Al2O3, 0-10% Na2O, 0-10% K2O, 0-15% Fe2O3 and 0-20% CaO.

[0021] Preferably, the aluminosilicate glass has a composition comprising (by weight) 55-75% SiO2, 5-15% Al2O3, 0-10% Na2O, 0-10% K2O, 0-10% Fe2O3, and 0-10% CaO.

[0022] Preferably, the aluminosilicate glass comprises (by weight) the following composition: 70-75% SiO2, 10-15% Al2O3, 2-7% Na2O, 2-7% K2O, and 0.5-3.5% Fe2O3.

[0023] Preferred aluminosilicate glass comprises (by weight) the following composition: 71-75% SiO2, 10-14% Al2O3, 2-6% Na2O, 2-6% K2O, and 0.5-2.5% Fe2O3 and 0-1% CaO.

[0024] Aluminosilicate glass may contain other impurities, such as manganese oxide and / or titanium dioxide. Preferably, the impurities are less than about 5% by weight.

[0025] The first powder comprises particles having a particle size distribution having: an average particle diameter; and a median particle diameter.

[0026] Preferably, the first powder comprises particles having a particle size distribution having: an average particle diameter of 1 μm to 250 μm; and / or a median particle diameter greater than 5 μm.

[0027] Without being theoretically limited, it is assumed that when the main surface of a glass sheet is treated with a powder containing particles, the particles induce at least one microcrack in the powder-treated main surface. When strength tests are performed by applying a test load to the powder-treated main surface of the glass sheet, the strength of the glass sheet is reduced compared to when the main surface of the glass sheet is not powder-treated. The strength of the glass can be determined using standard techniques, such as those described in ISO 1288-5 (2016).

[0028] The average particle diameter can be determined using a particle size analyzer such as the Beckman Coulter LS 13 320 particle size analyzer.

[0029] The median particle diameter in the particle size distribution is commonly referred to in the prior art as D50 or Dv(50), and is the size point below which 50% of the material is contained. D50 can be determined using a particle size analyzer such as the Beckman Coulter LS 13 320 particle size analyzer.

[0030] Preferably, the median particle diameter of the particle size distribution of the first powder is not greater than 100 micrometers.

[0031] By controlling the particle distribution of the first powder in this way, the number of small particles can be reduced, thereby reducing the amount of dust that may be generated during the processing steps. Avoiding dust is advantageous for processing steps prior to laminating the first glass sheet onto a second window glass material sheet, such as the second glass sheet, because any dust introduced into the lamination process can remain after the lamination process and be visible in the final laminated window glass.

[0032] Preferably, the average particle diameter of the particle size distribution is at least mp1 μm, wherein mp1 is 1, 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50.

[0033] The preferred particle size distribution has an average particle diameter of at most mp2 μm, where mp2 is 200, 150 or 100.

[0034] Preferably, the average particle diameter of the particle size distribution is in the range of mp1μm to mp2μm, wherein mp1 is 1, 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50, and mp2 is 200, 150 or 100.

[0035] Preferably, the median particle diameter in the particle size distribution is no greater than 90 μm.

[0036] Preferably, the median particle diameter in the particle size distribution is no greater than 80 μm.

[0037] Preferably, the median particle diameter in the particle size distribution is no greater than 70 μm.

[0038] Preferably, the median particle diameter in the particle size distribution is at least 10 μm.

[0039] Preferably, the median particle diameter of the particle size distribution is at least 15 μm, more preferably at least 20 μm, even more preferably at least 25 μm, and even more preferably at least 30 μm.

[0040] Preferably, the median particle diameter of the particle size distribution is in the range of md1μm to md2μm, where md1 is 5, 10, 15, 20, 25 or 30, and md2 is 100, 90, 80, 70, 60 or 50.

[0041] Preferably, the treatment method can appropriately reduce the strength of the treated glass sheet while avoiding visually observable scratches on the main surface of the glass.

[0042] Particles in a particle distribution have a lower limit diameter and an upper limit diameter.

[0043] The upper limit diameter can be defined as: in a sample used to determine particle size distribution, at most the total volume occupied by particles of that size and containing that size occupies 90% of the total material volume. The upper limit diameter can be referred to as D90 or Dv(90). For example, if D90 is 200 μm, this means that 90% of the sample has a size of 200 μm or smaller. D90 can be determined using a particle size analyzer such as the Beckman Coulter LS 13 320 particle size analyzer.

[0044] The lower limit diameter can be defined as a particle diameter below which 10% of the material used to determine particle distribution is contained. When defined in this way, the lower limit diameter may be referred to as D10 and can be determined using a particle size analyzer such as the Beckman Coulter LS 13 320 particle size analyzer.

[0045] The parameters D10, D50, and D90 have been used in size distribution measurements by laser diffraction for many years and are well known to those skilled in the art.

[0046] Preferably, the particle size distribution has a D10 of greater than 1 μm, and more preferably not greater than 20 μm, more preferably not greater than 15 μm, and even more preferably not greater than 10 μm.

[0047] Preferably, the particle size distribution has a D90 greater than 50 μm.

[0048] The preferred particle size distribution has a D90 greater than Dw μm, where Dw is 60, 70, 80, 90, 100, 125 or 150.

[0049] Preferably, the particle size distribution has a D90 of less than Dx μm, where Dx is 500, 400, 300, or 200.

[0050] The particle size distribution has a span defined as (D90-D10) / D50, and gives an indication of how far apart D10 and D90 are, normalized by the midpoint.

[0051] Preferably, the particle size distribution of the first powder has a range of 0.5 to 15, which is defined as (D90-D10) / D50.

[0052] Preferably, the span is between 1 and 15, more preferably between 1 and 10, and even more preferably between m and n, where m is 1.5, or 2, or 2.5, and n is 3, or 4, or 5, or 6, or 7, or 8, or 9.

[0053] It was also found that parameters D90-D10 can provide useful indicators of suitability for a particular powder used in this invention.

[0054] Preferably, D90-D10 is at least 30 μm, more preferably D90-D10 is at least Da μm, wherein Da is 40, 50, 60, 70, 80, 90 or 100.

[0055] Preferably, D90-D10 is at most 400 μm, more preferably D90-D10 is at most Db μm, wherein Db is 350, 300, 250 or 200.

[0056] Preferably, the particle size distribution has a mode particle diameter of at least 50 μm, more preferably at least 75 μm, even more preferably at least 100 μm, and even more preferably at least 125 μm.

[0057] Preferably, the particle size distribution has a mode particle diameter of up to 300 μm, more preferably up to 250 μm, and even more preferably up to 200 μm.

[0058] During the processing steps, pressure is preferably used to coat the first powder onto the first main surface of the first glass sheet. Preferably, the powder is applied to a depth of 1-2 cm. 2 The pressure over the area is less than about 0.01 MPa. Preferably, the pressure will not cause the particles to break.

[0059] The pressure applied is sufficient to reduce the strength of the treated first glass sheet to the desired level, whether used alone or as a panel in a laminated window glazing system incorporating such a treated glass sheet. The effect on the strength of the treated first glass sheet can be assessed using strength measurement methods known in the art, such as those defined in ISO 1288-5 (2016).

[0060] The powder used in the processing steps comprises particles with a hardness value sufficient to mark the glass surface with scratches, cracks, or microcracks. Hardness can be measured using standard methods, such as those used to determine Vickers hardness, and can be the hardness of a sheet of material having the same or substantially the same composition as the first powder. Suitable Vickers hardness tests are described in ASTM C1327-08. For example, hardness can be determined by measuring the hardness of a single substance subsequently ground to form the first powder. Float glass, such as soda-lime glass, typically has a Vickers hardness of 5.2 GPa to 5.8 GPa. Particles with a Vickers hardness of less than 10 GPa are preferred. Particles with a hardness much greater than that of the glass being processed tend to cause too many and / or too deep marks, i.e., scratches, which may affect the optical properties of the glass sheet being processed. Preferably, the hardness of the particles in the first powder is about 1.1-2, or 1.5-2 times, the hardness of the first glass sheet.

[0061] In some implementations, a powder applicator is used to apply a first powder to a first main surface of a first glass sheet.

[0062] When using a powder applicator, a first powder may be applied to a first main surface of a first glass sheet and then rubbed with the powder applicator; and / or the first powder may be applied to a powder applicator and the powder applicator having the first powder thereon may be rubbed onto the first main surface of the first glass sheet.

[0063] In some embodiments, a first powder is applied to a first main surface of a first glass sheet by a powder applicator, which includes at least one of a cloth, a brush, a scraper, and a roller.

[0064] When using a cloth, the first powder may be applied to the first main surface of the first glass sheet and then wiped with the cloth; and / or the first powder may be applied to a cloth and the cloth with the first powder may be wiped onto the first main surface of the first glass sheet.

[0065] When using a brush, the first powder may be applied to the first main surface of the first glass sheet and then rubbed with the brush; and / or the first powder may be applied to a brush and the brush with the first powder may be rubbed onto the first main surface of the first glass sheet.

[0066] When using a scraper, the first powder may be applied to the first main surface of the first glass sheet and then wiped with the scraper; and / or the first powder may be applied to a scraper and the scraper with powder on it may be wiped onto the first main surface of the first glass sheet.

[0067] When using a roller, the first powder may be applied to the first main surface of the first glass sheet and then rubbed with the roller; and / or the first powder may be applied to a roller and the roller with the first powder on it may be rubbed onto the first main surface of the first glass sheet.

[0068] Preferably, the scraper comprises an elastomeric material.

[0069] When using a brush, preferably, the brush comprises a plurality of bristles.

[0070] When using a brush, a rotating brush is preferably used in the processing steps. Preferably, during the processing steps, the rotating brush has a rotation axis that is transverse to the first main surface of the first glass sheet during processing.

[0071] Preferably, during processing, the rotational speed of the rotating brush relative to the first main surface of the first glass sheet is less than 1000 rpm; more preferably, during processing, the rotational speed of the rotating brush relative to the first main surface of the first glass sheet is between 50 and 500 rpm; even more preferably, during processing, the rotational speed of the rotating brush relative to the first main surface of the first glass sheet is between 100 and 300 rpm.

[0072] When using a brush, the duration of the processing step can depend on the size of the brush, the number of bristles per unit area of ​​the brush or each brush, and the speed of the brush relative to the first main surface of the first glass sheet during processing. For example, similar results can be obtained when processing with a brush at a rotational speed of S1 relative to the first main surface of the first glass sheet for a duration T1, and with a brush at a rotational speed of 1 / 2S1 for a duration of 2T1.

[0073] It is advantageous if the brush bristles consist of synthetic materials, preferably nylon (e.g., nylon 612 or nylon 66) or polyester. However, other types of bristles may also be used in the processing steps.

[0074] It is evident that the properties of the bristles can be altered so that each bristle contains a certain amount of particles, particularly abrasive particles. Examples of such bristles are disclosed in US4,507,361 and US5,226,929. Methods for manufacturing bristles with abrasive fillers are known, for example, as described in US3,522,342.

[0075] Preferably, the diameter of the brush bristles is in the range of 0.1 to 1 mm, more preferably in the range of 0.2 to 0.8 mm, and even more preferably in the range of 0.2 to 0.6 mm. Preferably, the length of the brush bristles will be in the range of 5 to 50 mm, more preferably 10 to 45 mm, and most preferably 20 to 40 mm.

[0076] In some implementations, a fluid carrier is used to direct the first powder toward the first primary surface of the glass sheet.

[0077] Preferably, the fluid carrier comprises a gas, more preferably nitrogen or air.

[0078] Preferably, the fluid carrier comprises a liquid, more preferably water.

[0079] Preferably, the fluid carrier is in the form of a jet.

[0080] When the fluid is a liquid, it is preferably in the form of a jet or droplets.

[0081] Preferably, the fluid carrier impacts the first primary surface of the glass sheet at a velocity, wherein the velocity of the fluid carrier is preferably less than 200 m / s, more preferably between 1 m / s and 100 m / s. The fluid velocity is selected to achieve the desired strength reduction of the first glass sheet.

[0082] In some embodiments, a liquid is used in the processing step of treating the first main surface of the first glass sheet with the first powder.

[0083] Preferably, the liquid contains water.

[0084] Preferably, the first powder is dispersed in a liquid.

[0085] The liquid in which the first powder is dispersed can be a slurry.

[0086] In some embodiments, the second main surface of the first glass sheet is treated with a second powder, the second powder having a composition and containing particles having a particle size distribution.

[0087] Preferably, the second main surface of the first glass sheet is processed during the processing steps, although the second main surface of the first glass sheet may be processed before, after, and / or simultaneously with the first main surface of the first glass sheet being treated with the first powder.

[0088] Preferably, the particle size distribution of the second powder is the same as that of the first powder.

[0089] Preferably, the composition of the second powder is the same as that of the first powder.

[0090] Preferably, the second powder is the same as the first powder.

[0091] In some embodiments, the first glass sheet is a panel of laminated window glass comprising a first glass sheet bonded to a window glass material sheet via an interlayer structure comprising at least one adhesive interlayer material sheet, the panel of the laminated window glass having an exposed main surface, wherein the exposed main surface comprises a first main surface of the first glass sheet.

[0092] The exposed main surface of the laminated window glass does not face the intermediate layer structure.

[0093] Using conventional nomenclature, the exposed primary surface of laminated window glass is either surface one or surface four of the laminated window glass.

[0094] Preferably, the window glass material is a glass sheet or a plastic sheet.

[0095] Preferably, the window glass sheet has a thickness of 1 mm to 5 mm, more preferably 1.3 mm to 3 mm.

[0096] Preferably, the window glass sheet is a chemically strengthened glass sheet with a thickness between 0.4 mm and 1.3 mm.

[0097] Preferably, the window glass sheet is thinner than the first glass sheet.

[0098] Preferably, laminated window glass is used for vehicle windows, especially car windshields.

[0099] Preferably, the window glass sheet is a glass sheet produced using the float glass process, and the first main surface of the window glass sheet is the tin side, while the second opposing main surface of the window glass sheet is the air side.

[0100] Preferably, the window glass sheet is a glass sheet produced using the float glass process, and the first main surface of the window glass sheet is the air side, while the second main surface of the window glass sheet is the tin side.

[0101] Preferably, the window glass sheet is soda-lime silicate glass, which has the following composition (by weight): SiO2 69-74%; Al2O3 0-3%; Na2O 10-16%; K2O 0-5%; MgO 0-6%; CaO 5-14%; SO3 0-2%.

[0102] In an embodiment where the first glass sheet is a panel of laminated window glass, the laminated window glass includes a first glass sheet bonded to a window glass material sheet via an interlayer structure comprising at least one adhesive interlayer material sheet. The panel of the laminated window glass has an exposed main surface, and wherein the exposed main surface comprises the first main surface of the first glass sheet. Preferably, the laminated window glass is a vehicle window, particularly a car windshield.

[0103] Preferably, the laminated window glass has a Head Injury Criterion (HIC) value of less than 700, more preferably less than 650, and even more preferably less than 600. The Head Injury Criterion (HIC) is commonly referred to as the Head Impact Criterion (HIC).

[0104] Preferably, the HIC value is measured at grid locations A, 12, a according to EURO-NCAP Vulnerable Road User Testing Protocol Version 9.0.2, where a is between -4 and +4, preferably between -3 and +3, more preferably between -2 and +2; and an impact velocity of 40 km / h.

[0105] Preferably, the header format used to determine the HIC value is as described in UN Regulation No. 127 (E / ECE / 324 / Rev.2 / Add.126 / Rev.2).

[0106] In some embodiments, the first glass sheet is produced using a float glass process, and wherein a first primary surface of the first glass sheet is tin-side and a second primary surface of the first glass sheet is air-side.

[0107] In some embodiments, the first glass sheet is produced using a float glass process, wherein the first primary surface of the first glass sheet is air-side and the second primary surface of the first glass sheet is tin-side.

[0108] In a preferred embodiment, the processing steps do not include a grinding step. In such embodiments, it is preferred that the first glass sheet is produced using a float process, a rolling process, or a pull-down process. As is known in the art, glass sheets produced by the float process have a fired polished surface with good optical quality and parallel main surfaces, requiring no subsequent grinding and / or repolishing. In these embodiments, the processing steps are not used to improve the optical quality of the formed first glass sheet, although it is apparent that if a portion of the first glass sheet is soiled prior to the processing steps, the first processing steps will also clean any contamination on the portion of the first main surface of the first glass sheet. Therefore, it is preferable to clean the first main surface of the first glass sheet prior to the processing steps.

[0109] In some embodiments, the processing steps include at least a first cleaning step. The first cleaning step may be performed before or after powder treatment of a portion of the first main surface of the first glass sheet. The portion of the first main surface of the powder-treated first glass sheet may be cleaned before and after powder treatment.

[0110] Cleaning can be performed using known cleaning methods, including fluids and / or contact materials such as cloths, brushes, and sponges.

[0111] Preferably, the first cleaning step is used to remove dirt and the like from the first main surface of the first glass sheet without reducing the strength of the first glass sheet.

[0112] In some implementations, the particles have a first particle size distribution before the processing step and a second particle size distribution after the processing step, wherein the first particle size distribution is the same as or substantially the same as the second particle size distribution.

[0113] In these embodiments, it is preferred that when the particles are used to treat a first portion of the first main surface of the first glass sheet, the particles do not break, or any breakage of the particles used to treat the first portion of the first main surface of the first glass sheet results in a reduction of only 5% to 50% in the D90 of the particles in the powder. For example, the D90 of the first particle size distribution may be 500 μm, and the D90 of the second particle size distribution may be about 250 μm to 475 μm.

[0114] Other embodiments of the first aspect of the present invention have other preferred features.

[0115] Preferably, the first powder contains no or substantially no cerium dioxide. When the first powder contains no or substantially no cerium dioxide, the first powder does not contain any intentionally added cerium dioxide particles.

[0116] Preferably, the first powder contains no or substantially no rouge. When the first powder contains no or substantially no rouge, it contains no intentionally added rouge particles.

[0117] Preferably, the first powder is essentially composed of powdered aluminosilicate glass.

[0118] Preferably, the particles are primarily composed of aluminosilicate glass.

[0119] Preferably, the first powder is a powdered aluminosilicate glass containing multiple particles.

[0120] Preferably, the first powder has a composition comprising (by weight) 40-75% SiO2, 5-20% Al2O3, 0-10% Na2O, 0-10% K2O, 0-15% Fe2O3, and 0-20% CaO.

[0121] Preferably, the first powder has a composition comprising (by weight) 65-75% SiO2, 5-15% Al2O3, 0-10% Na2O, 0-10% K2O, 0-10% Fe2O3 and 0-10% CaO.

[0122] Preferably, the first powder has a composition comprising (by weight) 55-75% SiO2, 5-15% Al2O3, 0-10% Na2O, 0-10% K2O, 0-10% Fe2O3 and 0-10% CaO.

[0123] Preferably, the first powder has a composition comprising (by weight) 70-75% SiO2, 10-15% Al2O3, 2-7% Na2O, 2-7% K2O, and 0.5-3.5% Fe2O3.

[0124] Preferably, the first powder has a composition comprising (by weight) 71-75% SiO2, 10-14% Al2O3, 2-6% Na2O, 2-6% K2O, 0.5-2.5% Fe2O3 and 0-1% CaO.

[0125] Preferably, the particles of the first powder do not have a heterogeneous aggregate structure.

[0126] Preferably, the first powder does not contain unexpanded perlite.

[0127] Preferably, the aluminosilicate glass is not perlite.

[0128] Preferably, prior to the processing step, a portion of the first primary surface of the first glass sheet has a first visible light transmittance, and after the processing step, a portion of the first primary surface of the first glass sheet has a second visible light transmittance, wherein the second visible light transmittance is at least 70%. The visible light transmittance can be measured according to recognized standards, such as BS EN410 (2011).

[0129] Preferably, when the first glass sheet is flat, the first main surface of the first glass sheet is treated with a first powder, and then the first glass sheet is shaped using a forming process, such that after shaping, the radius of curvature of the first glass sheet in at least one direction is between 500 mm and 10000 mm, preferably between 1000 mm and 8000 mm.

[0130] Preferably, after the first glass sheet has been formed using a forming process, the first main surface of the first glass sheet is treated with a first powder, such that after the forming process, the radius of curvature of the first glass sheet in at least one direction is between 500 mm and 10000 mm, preferably between 1000 mm and 8000 mm.

[0131] Preferably, the first main surface of the first glass sheet is treated with the first powder before and after forming.

[0132] Preferably, during the processing step, the area of ​​a portion of the first main surface of the first glass sheet treated with the first powder is smaller than the area of ​​the first main surface of the first glass sheet.

[0133] Preferably, during the processing step, the area of ​​a portion of the first main surface of the first glass sheet treated with the first powder is 10%-80% of the area of ​​the first main surface of the first glass sheet.

[0134] Preferably, during the processing step, a portion of the first primary surface of the first glass sheet treated with powder extends to at least one peripheral edge of the first primary surface of the first glass sheet.

[0135] The thickness of the first glass sheet is preferably between 1 mm and 5 mm, and more preferably between 1.3 mm and 3 mm.

[0136] Preferably, the first main surface of the first glass sheet is a convex surface.

[0137] Preferably, the first main surface has an optically transparent coating that reflects and / or absorbs infrared radiation on at least a portion thereof.

[0138] Preferably, the first main surface of the first glass sheet is convex.

[0139] Preferably, the first glass sheet is a sodium-calcium silicate glass sheet, particularly a float glass sheet.

[0140] Preferably, the first glass sheet is manufactured using the float glass process. Other methods for manufacturing glass sheets, such as rolling and drawing, may also be used.

[0141] Sodium-calcium silicate glass is commonly referred to as sodium-calcium silicate glass, or simply as "sodium-calcium" glass sheet.

[0142] Preferably, the first glass sheet is soda-lime silicate glass, having the following composition (by weight): SiO2 69-74%; Al2O3 0-3%; Na2O 10-16%; K2O 0-5%; MgO 0-6%; CaO 5-14%; SO3 0-2%; Fe2O3 0.005-2%.

[0143] Preferably, the first glass sheet is not chemically strengthened. When the glass sheet has not undergone ion exchange or has undergone ion processing and the subsequent layer depth is 0 μm to Dxo μm, the glass sheet can be classified as not chemically strengthened, where Dxo is 1, 2, 3, 4, or 5.

[0144] Preferably, the first glass sheet is an alkaline aluminosilicate glass sheet, which preferably contains at least about 6 wt% (by weight) alumina (Al2O3) and / or is preferably chemically strengthened.

[0145] In some embodiments, a portion of the first primary surface of the first glass sheet has an initial roughness before being treated with the first powder, and a final roughness after being treated with the first powder, wherein the treated portion of the first primary surface of the first glass sheet includes a region with surface roughness having an Rz of less than 20 μm. As known to those skilled in the art, Rz is the maximum height of the profile, which is the sum of the maximum profile peak height and the maximum profile valley depth within the sampling length. The sampling length can be less than 5 cm, preferably between 0.5 cm and 4 cm, or between 0.5 cm and 3 cm, or between 0.5 cm and 2 cm, or between 0.5 cm and 1 cm. The sampling length can be greater than or equal to 1 cm.

[0146] In some embodiments, a portion of the first primary surface of the first glass sheet has an initial roughness before being treated with the first powder, and a final roughness after being treated with the first powder, wherein the treated portion of the first primary surface of the first glass sheet includes a region with a surface roughness having a Ra of less than 5 μm, preferably less than 4 μm, or 3 μm, 2 μm, or 1 μm. Ra is the arithmetic mean deviation of the profile within the sampling length. The sampling length can be less than 5 cm, preferably between 0.5 cm and 4 cm, or between 0.5 cm and 3 cm, or between 0.5 cm and 2 cm, or between 0.5 cm and 1 cm. The sampling length can be greater than or equal to 1 cm.

[0147] In some embodiments, a portion of the first primary surface of the first glass sheet has an initial roughness before being treated with the first powder, and a final roughness after being treated with the first powder, wherein the treated portion of the first primary surface of the first glass sheet includes a region with surface roughness having an Rmax of at least 10 μm and / or preferably at most 25 μm. Rmax is the maximum single roughness depth within the sampling length. The sampling length can be less than 5 cm, preferably between 0.5 cm and 4 cm, or between 0.5 cm and 3 cm, or between 0.5 cm and 2 cm, or between 0.5 cm and 1 cm. The sampling length can be greater than or equal to 1 cm.

[0148] In some embodiments, a portion of the first primary surface of the first glass sheet has an initial roughness before being treated with the first powder and a final roughness after being treated with the first powder, wherein the treated portion of the first primary surface of the first glass sheet includes a region with surface roughness having an Rv of up to 20 μm. Rv is the maximum profile valley depth (Rv) within the sampling length. The sampling length can be less than 5 cm, preferably between 0.5 cm and 4 cm, or between 0.5 cm and 3 cm, or between 0.5 cm and 2 cm, or between 0.5 cm and 1 cm. The sampling length can be greater than or equal to 1 cm.

[0149] In some embodiments, a portion of the first primary surface of the first glass sheet has an initial roughness before being treated with the first powder, and a final roughness after being treated with the first powder, wherein the treated portion of the first primary surface of the first glass sheet includes a region with surface roughness having an Rz of less than about 8 μm. The sampling length can be less than 5 cm, preferably between 0.5 cm and 4 cm, or between 0.5 cm and 3 cm, or between 0.5 cm and 2 cm, or between 0.5 cm and 1 cm. The sampling length can be greater than or equal to 1 cm.

[0150] In some embodiments, a portion of the first primary surface of the first glass sheet has an initial roughness before being treated with the first powder, and a final roughness after being treated with the first powder, wherein the treated portion of the first primary surface of the first glass sheet includes a region having a surface roughness having an Ra value in the range of 0.3 μm to 2 μm. The sampling length can be less than 5 cm, preferably between 0.5 cm and 4 cm, or between 0.5 cm and 3 cm, or between 0.5 cm and 2 cm, or between 0.5 cm and 1 cm. The sampling length can be greater than or equal to 1 cm.

[0151] In some embodiments, a portion of the first primary surface of the first glass sheet has an initial roughness before being treated with the first powder, and a final roughness after being treated with the first powder, wherein the treated portion of the first primary surface of the first glass sheet includes a region with surface roughness having an Rmax of at least 1 μm and / or preferably at most 10 μm. The sampling length can be less than 5 cm, preferably between 0.5 cm and 4 cm, or between 0.5 cm and 3 cm, or between 0.5 cm and 2 cm, or between 0.5 cm and 1 cm. The sampling length can be greater than or equal to 1 cm.

[0152] In some embodiments, a portion of the first primary surface of the first glass sheet has an initial roughness before being treated with the first powder, and a final roughness after being treated with the first powder, wherein the treated portion of the first primary surface of the first glass sheet includes a region having a surface roughness having an Rv of at most 4 μm, preferably at most 3 μm, and / or preferably at least 0.5 μm. The sampling length can be less than 5 cm, preferably between 0.5 cm and 4 cm, or between 0.5 cm and 3 cm, or between 0.5 cm and 2 cm, or between 0.5 cm and 1 cm. The sampling length can be greater than or equal to 1 cm.

[0153] In some embodiments, a portion of the first primary surface of the first glass sheet has an initial roughness before being treated with the first powder, and a final roughness after being treated with the first powder. The treated portion of the first primary surface of the first glass sheet includes a region with a surface roughness having an Rz of at most 10 μm, and preferably at most 40 μm, or preferably at most 35 μm, or more preferably at most 30 μm. The sampling length can be less than 5 cm, preferably between 0.5 cm and 4 cm, or between 0.5 cm and 3 cm, or between 0.5 cm and 2 cm, or between 0.5 cm and 1 cm. The sampling length can be greater than or equal to 1 cm.

[0154] In some embodiments, a portion of the first primary surface of the first glass sheet has an initial roughness before being treated with the first powder, and a final roughness after being treated with the first powder, wherein the treated portion of the first primary surface of the first glass sheet includes a region with surface roughness having an Ra value in the range of 0.1 μm to 8 μm. The sampling length can be less than 5 cm, preferably between 0.5 cm and 4 cm, or between 0.5 cm and 3 cm, or between 0.5 cm and 2 cm, or between 0.5 cm and 1 cm. The sampling length can be greater than or equal to 1 cm.

[0155] In some embodiments, a portion of the first primary surface of the first glass sheet has an initial roughness before being treated with the first powder, and a final roughness after being treated with the first powder, wherein the treated portion of the first primary surface of the first glass sheet includes a region with surface roughness having an Rmax of up to 20 μm. The sampling length can be less than 5 cm, preferably between 0.5 cm and 4 cm, or between 0.5 cm and 3 cm, or between 0.5 cm and 2 cm, or between 0.5 cm and 1 cm. The sampling length can be greater than or equal to 1 cm.

[0156] In some embodiments, after treatment with the first powder, the first glass sheet has

[0157] The increase in haze is less than approximately 5%. Haze measurements can be performed using the BYK Hazegard Plus in transmission mode, or using a spectrometer such as the Perkin-Elmer Lambda 1050.

[0158] The present invention provides a method for manufacturing laminated window glass from a second aspect, comprising the steps of: (i) providing a first glass sheet having a first main surface and a second opposing main surface; (ii) reducing the strength of the first glass sheet using a method according to the first aspect of the invention; and (iii) laminating the first glass sheet to the window glass sheet using an interlayer structure comprising at least one adhesive interlayer material sheet; wherein the first main surface of the first glass sheet faces the interlayer structure, or wherein the second main surface of the first glass sheet faces the interlayer structure.

[0159] As is conventional in the prior art, surface one of the laminated window glass is the outermost surface of the laminated window glass, and surface four of the laminated window glass is an inward-facing surface defined relative to the interior of the vehicle or building in which the laminated window glass is installed. The inward-facing surface of the laminated window glass faces the interior of the vehicle or building in which the laminated window glass is installed. The outermost surface (usually referred to as the outer surface) faces the exterior of the vehicle or building in which the laminated window glass is installed.

[0160] Preferably, the first glass sheet is washed after step (ii) and before step (iii) to remove any powder therefrom, otherwise the powder may end up remaining in the final laminated window glass.

[0161] Preferably, step (ii) is performed before and after step (iii), with the first main surface of the first glass sheet facing the intermediate layer structure. In such an embodiment, the first main surface of the first glass sheet is preferably surface two or surface three of the laminated window glass.

[0162] Preferably, the second main surface of the first glass sheet is treated with a second powder having a composition and containing particles having a particle size distribution, wherein the second main surface of the first glass sheet is treated before or after step (iii).

[0163] Preferably, step (ii) is performed before step (iii), and wherein after step (iii), the second main surface of the first glass sheet faces the intermediate layer structure.

[0164] The embodiment in which step (ii) occurs before and after step (iii) has other preferred features, with the second main surface of the first glass sheet facing the intermediate layer structure.

[0165] Preferably, the first main surface of the first glass sheet is surface one or surface four of the laminated window glass.

[0166] Preferably, prior to step (iii), the second main surface of the first glass sheet is treated with a second powder having a composition and containing particles having a particle size distribution.

[0167] Preferably, during step (ii), the second main surface of the first glass sheet is treated with the second powder.

[0168] The thickness of the first glass sheet is preferably between 1 mm and 5 mm, and more preferably between 1.3 mm and 3 mm.

[0169] Preferably, the window glass sheet has a thickness between 1 mm and 5 mm, more preferably between 1.3 mm and 3 mm.

[0170] Preferably, the window glass sheet is thinner than the first glass sheet.

[0171] Preferably, the window glass sheet is a second glass sheet having its strength reduced using the method according to the first aspect of the invention.

[0172] Preferably, the laminated window glass is a window used for openings in the vehicle.

[0173] Preferably, the laminated window glass is the windshield of the vehicle.

[0174] Preferably, the laminated window glass is bent in at least one direction. Preferably, the radius of curvature in at least one direction is between 500 mm and 20,000 mm, more preferably between 1,000 mm and 8,000 mm.

[0175] Preferably, at least one adhesive interlayer material sheet includes polyvinyl butyral (PVB), acoustically modified PVB, ethylene copolymers such as ethylene-vinyl acetate copolymer (EVA), polyurethane (PU), polyvinyl chloride (PVC), ethylene and methacrylic acid copolymer (EMA), or Uvekol (liquid curable resin).

[0176] Preferably, at least one adhesive interlayer material sheet is a sheet of polyvinyl butyral (PVB), EVA, PVC, EMA, polyurethane, acoustically modified PVB, or Uvekol (liquid curable resin).

[0177] Preferably, at least one adhesive interlayer material sheet has a thickness of 0.3 mm to 2.3 mm, more preferably 0.3 mm to 1.6 mm, and most preferably between 0.3 mm and 0.8 mm.

[0178] Preferably, the interlayer structure comprises 2, 3, 4, 5, 6, 7, 8, 9, 10, or more sheets of adhesive interlayer material. Each sheet of adhesive interlayer material may be of the same type, i.e., all are PVB and may all have the same thickness.

[0179] Preferably, the intermediate layer structure comprises at least one polyester sheet, more preferably at least one polyethylene terephthalate (PET) sheet, and preferably, at least one polyester sheet has an optically transparent coating on at least one of its main surfaces that reflects and / or absorbs infrared radiation.

[0180] Preferably, the first glass sheet is a sodium-calcium silicate glass sheet, particularly a float glass sheet.

[0181] Preferably, the window glass sheet is a sodium-calcium silicate glass sheet, especially a float glass sheet.

[0182] Preferably, the first glass sheet is not chemically strengthened. When the glass sheet has not undergone an ion exchange process or has undergone an ion exchange process and the subsequent layer depth is between 0 μm and Dxo μm, the glass sheet can be classified as unchemically strengthened, where Dxo is 1, 2, 3, 4, or 5.

[0183] In some implementations, the laminated window glass achieves a Head Injury Criterion (HIC) value of less than 700, more preferably less than 650, and even more preferably less than 600. The Head Injury Criterion (HIC) is commonly referred to as the Head Impact Criterion (HIC).

[0184] Preferably, the HIC value is measured at grid positions A, 12, a according to EURO-NCAP Vulnerable Road User Test Protocol version 9.0.2, where a is between -4 and +4, preferably between -3 and +3, more preferably between -2 and +2; and an impact velocity of 40 km / h.

[0185] Preferably, the header format used to determine the HIC value is as described in UN Regulation No. 127 (E / ECE / 324 / Rev.2 / Add.126 / Rev.2) Annex 4.

[0186] In some implementations, the window glass sheet is an alkaline aluminosilicate glass sheet.

[0187] Preferably, the alkaline aluminosilicate glass sheet contains at least about 6% by weight of alumina (Al2O3).

[0188] In some embodiments, the window glass sheet is a chemically strengthened glass sheet, wherein preferably, the window glass sheet has a thickness of less than 1.2 mm, more preferably between 0.3 mm and 1 mm, and even more preferably between 0.4 mm and 0.9 mm.

[0189] In some embodiments, the window glass sheet is a second glass sheet whose strength has been reduced using the method according to the first aspect of the invention.

[0190] Preferably, the treated surface of the second glass sheet faces the intermediate layer structure.

[0191] In some implementations, a first glass sheet has been produced using a float glass process, and the first primary surface of the first glass sheet is tin-side, and the second primary surface of the first glass sheet is air-side.

[0192] In some implementations, a first glass sheet has been produced using a float glass process, and the first primary surface of the first glass sheet is air-side, and the second primary surface of the first glass sheet is tin-side.

[0193] In some embodiments, the window glass sheet is a glass sheet produced using the float glass process, and the first primary surface of the window glass sheet is tin-side, while the second opposing primary surface of the window glass sheet is air-side.

[0194] In some embodiments, the window glass sheet is a glass sheet produced using the float glass process, and the first main surface of the window glass sheet is the air side, and the second main surface of the window glass sheet is the tin side. Attached Figure Description

[0195] The invention will now be described with reference to the following figures (not to scale), in which:

[0196] Figure 1 This is a cross-sectional view of the laminated window glass manufactured according to the present invention;

[0197] Figure 2 This is a plan view of the laminated window glass manufactured according to the present invention;

[0198] Figure 3 It is a diagram showing details of the particle distribution used to process glass sheets to reduce their strength; and

[0199] Figure 4 It is a view of the interior of a vehicle having a windshield manufactured according to the present invention. Detailed Implementation

[0200] Figure 1 A cross-sectional view of a curved laminated window glaze manufactured according to the present invention is shown.

[0201] The laminated window glass 1 has a first soda-lime silicate glass sheet 3, which has a composition such as clear float glass and may include a colorant such as iron oxide to provide laminated window glass with some form of sunlight control. The first sheet 3 has a thickness of 2.1 mm, although this thickness may be in the range of 1.4 mm to 2.5 mm or in the range of 1.6 mm to 2.3 mm.

[0202] A typical soda-lime silicate glass composition (by weight) is: SiO2 69-74%; Al2O3 0-3%; Na2O 10-16%; K2O 0-5%; MgO 0-6%; CaO 5-14%; SO3 0-2%; Fe2O3 0.005-2%. The glass composition may also contain other additives, such as clarifying agents, which are typically present in amounts up to 2%. Soda-lime silicate glass compositions may contain other colorants such as Co3O4, NiO, and Se to impart the desired color to the glass when viewed under transmitted light. The transmitted glass color can be measured according to recognized standards such as BS EN410 (2011).

[0203] The laminated window glass 1 also has a second sodium calcium silicate glass sheet 7 with a thickness of 2.1 mm, but the second sheet may have a thickness in the range of 1.4 mm to 2.5 mm, and preferably is not as thick as the first sheet 3.

[0204] In this embodiment, the first glass sheet 3 is an outer sheet (or outer panel) and the second glass sheet 7 is an inner sheet (or inner panel). As is known in the art, the outer sheet faces the exterior of the vehicle in which the laminated glass 1 is installed or to be installed, and the inner sheet faces the interior of the vehicle in which the laminated glass is installed or to be installed.

[0205] The first sheet 3 is bonded to the second sheet 7 via an adhesive interlayer structure 5. In this embodiment, the adhesive interlayer structure 5 is a 0.76 mm thick PVB sheet. The adhesive interlayer structure 5 can have a thickness between 0.3 mm and 1.8 mm.

[0206] Other suitable adhesive interlayers include PVC, EVA, EMA, and polyurethane. Interlayer structure 5 may include two or more adhesive interlayer material sheets. The adhesive interlayer material may contain heat-absorbing and / or heat-reflecting particles, such as indium tin oxide (ITO). A carrier sheet, such as polyethylene terephthalate (PET), may be present between the two adhesive interlayer material sheets, and the carrier sheet may have a coating on its main surface. This coating may be infrared-reflective and may contain one, two, three, or more silver-containing layers.

[0207] The laminated window glass 1 is bent in one or more directions. The radius of curvature in one of the one or more directions is between 1000 mm and 8000 mm.

[0208] When laminated window glass is bent in two directions, each direction of bending is preferably orthogonal to the other. Preferably, the radius of curvature in one or both directions is between 1000 mm and 8000 mm.

[0209] The first sheet 3 has a protruding first main surface 9 and an opposing recessed second main surface 11. The second sheet 7 has a protruding third main surface 13 and an opposing recessed fourth main surface 15. The recessed surface 11 of the first sheet 3 contacts the adhesive interlayer 5, while the protruding surface 13 of the second sheet 7 contacts the adhesive interlayer 5. Using conventional nomenclature, the protruding main surface 9 of the first sheet 3 is "surface one" (or S1) of the laminated window glass 1, the recessed main surface 11 of the first sheet 3 is "surface two" (or S2) of the laminated window glass 1, the protruding main surface 13 of the second sheet 7 is "surface three" (or S3) of the laminated window glass 1, and the recessed main surface 15 of the second sheet 7 is "surface four" (or S4) of the laminated window glass 1.

[0210] In this embodiment, a treated central region 17 is present on the fourth surface (the recessed fourth main surface 15 of the second sheet 7 of sodium-calcium silicate glass) that has been powder-treated according to the present invention. Figure 1In the cross-sectional view, the treated central region 17 extends between the sides 17' and 17". In this embodiment, only the treated central region 17 is treated with the powder according to the invention. In other embodiments, at least one of surfaces one, two, three, and four has been treated with the powder according to the invention.

[0211] Either or both of the first sheet 3 and the second sheet 7 can be formed by the float glass process.

[0212] Figure 2 This is a schematic plan view of the laminated window glass 1, along... Figure 1 The direction of arrow 10.

[0213] exist Figure 2 In the middle, the perimeter of the laminated window glass is typical of a vehicle windshield. Figure 1 It is a cross-sectional view along the plane including line n-n'.

[0214] In this embodiment, the masking strip 21 is located on the recessed fourth main surface 15 of the second sheet 7. The masking strip 21 is optically opaque and is applied to the glass in a conventional manner before the second sheet 7 is formed. The masking strip 21 is a coating that is screen-printed onto the glass surface and fused to the glass surface by heat.

[0215] Inside the shielding strip 21, the laminated window glass 1 has a viewing area 23. In the prior art, the permissible light transmittance of a vehicle windshield is typically set by regulations such as ECE R43. In this embodiment, the viewing area displays 70% or more of the total visible light transmittance (light source A, two-degree observer), as measured under normal incidence. Visible light transmittance can be measured according to recognized standards such as BSEN410 (2011).

[0216] Set the processed center region 17 in the center region of the perspective region 23. Figure 2 In the image, the processed central area 17 is shown as a dashed line, but in the laminated window glass 1, it is impossible to determine the position of the processed central area 17 with the naked eye.

[0217] In this example, the processing area 17 is a rectangular area with a first side 17a, a second side 17, a third side 17c, and a fourth side 17d. The area of ​​the processed central area 17 is approximately 40% of the area of ​​the perspective area, but can be 10%-80% of the area of ​​the perspective area 23.

[0218] The laminated window glass 1 has corners h, j, k, and l in the plan view, such that when viewed in the direction of arrow 10, the laminated window glass has an upper edge hj, a lower edge kl, a right edge jk, and a left edge lh. The processed central region 17 is located within the area defined by corners h, j, k, and l.

[0219] In this example, the central processing area 17 has a rectangular shape, but the processed central area can have other shapes, such as square, ellipse, circle, or irregular shape. Side 17a can be parallel to the upper edge hj of the laminated window glass. Side 17b can be parallel to the right edge jk of the laminated window glass. Side 17c can be parallel to the lower edge kl of the laminated window glass. Side 17d can be parallel to the left edge lh of the laminated window glass. For example, sides 17a, 17b, and 17d can be as follows: Figure 2 As shown, however, side 17c can be curved and substantially parallel to the lower edge kl of the laminated window glass.

[0220] Preferably, the treated central region has sides that are evenly spaced from the edge of the shielding strip, although this is not required.

[0221] In some implementations, the treated area may extend from one side of the shielding strip, for example at the lower edge, and extend through the transparent area.

[0222] Returning to the illustrated embodiment, the treated central region 17 is part of the recessed fourth main surface 15 of the second glass sheet 7, which has been powder-treated according to the invention to reduce the strength of the laminated window glass 1.

[0223] When the laminated window glass 1 is installed as a windshield in a vehicle, in the event of a pedestrian being involved in a collision with the vehicle, the reduction in the strength of the windshield upon impact with the protruding first main surface 9 (due to the reduced strength of the second glass sheet 7) reduces the severity of pedestrian injuries, especially head injuries.

[0224] In this embodiment, the stacked windshield 1 is manufactured in a conventional manner, wherein first and second glass sheets 3, 7 are formed using suitable forming processes such as bending or gravity-assisted bending. The first and second glass sheets 3, 7 can be formed individually or simultaneously together, wherein the first and second glass sheets 3, 7 are formed in pairs. This can be done with the second glass sheet 7 on top of the first glass sheet 3. Alternatively, the first glass sheet 3 can be on top of the second glass sheet 7, and their order can be alternated before stacking. The formed glass sheets are then joined together using a conventional stacking method via a PVB sheet 5. After stacking, the windshield 1 is cleaned with deionized water, leaving its exposed surfaces with their original surfaces.

[0225] The laminated window glass 1 is supported around its perimeter so that it is recessed into the fourth main surface 15 facing upwards.

[0226] To treat the recessed fourth main surface 15, 2g of suitable powder is applied to the center 1' of the recessed fourth main surface 15 and spread evenly over an area to define a central treatment area, namely a rectangular area 17 having sides 17a, 17b, 17c, and 17d. In this embodiment, the treatment area has a size of approximately 80cm × 50cm.

[0227] According to "Glass Processing Days, 13-15 Sept 1997, pp. 40-44", the surface roughness of float glass has an Rz of <0.1 μm. Preferably, after powder treatment, the surface roughness of the powder-treated area is <1 μm, more preferably <0.5 μm. The location of the powder applied to the recessed fourth main surface 15 cannot be determined by the naked eye.

[0228] In this embodiment, the powder is a commercially available pumice powder having the chemical composition shown in Table 1.

[0229]

[0230] Table 1

[0231] The particle size distribution of the powder was determined using a commercially available particle size analyzer, such as the Beckman Coulter LS 13 320 particle size analyzer, and is shown below. Figure 3 In. Figure 3 In the diagram, line 60 is the 'differential volume (%)' line, representing the percentage of particles within a certain diameter range. Line 62 is the 'cumulative > volume (%)' line, representing the percentage of particles with a diameter greater than a specific particle diameter. For example, approximately 76% of the particles have a particle diameter greater than 10 micrometers.

[0232] The average particle diameter of the powder was 62 μm, the median particle diameter (D50) was 33 μm, the mode particle diameter was 154 μm, the D10 particle diameter was 4.2 μm, and the D90 particle diameter was 169 μm. The particle size distribution span of the powder was 4.99. The values ​​of the average particle diameter, median particle diameter, mode particle diameter, D10 particle diameter, and D90 particle diameter were determined by measuring the powder sample using a Beckman Coulter LS13 320 particle size analyzer. That is, the particle size distribution of the powder sample was measured using a Beckman Coulter LS13 320 particle size analyzer to determine the above-mentioned characteristics.

[0233] The powder had 75% of the samples with particle sizes smaller than about 101 micrometers and 50% of the samples with particle sizes smaller than about 33 micrometers.

[0234] The powder comprises particles that are appropriately resistant to damaging the surface of the glass sheet being processed. These particles may be referred to as abrasive grains. The powder used in the embodiments described herein has a particle size distribution that does not generate excessive dust during the processing steps and has sufficiently large particles so that the processing steps can be performed in a sufficiently short time without creating excessive scratches that could degrade the optical quality of the glass.

[0235] Optical quality may include the measurement of haze and / or the methods described in WO2004 / 083835A1 or US5,694,479.

[0236] The powder used in the processing steps can be collected after the processing steps, and its particle size distribution can be determined using a suitable particle size analyzer such as the Beckman Coulter LS 13 320 particle size analyzer.

[0237] To determine the effect on the strength of glass sheets when a portion of the main surface of a glass sheet is treated with the aforementioned powder, a series of tests were conducted. These tests were performed on numerous soda-lime-silica glass sheets formed using the float glass process.

[0238] The glass sheets used for evaluation were monolithic, each with a nominal thickness of 4 mm. Each glass sheet was an annealed clear float glass sheet, which was cut and edge-finished to produce ten sets of 240 mm × 240 mm samples, see Table 2. Clear float glass refers to glass having a composition as defined in BS EN 572-1 and BS EN 572-2 (2012).

[0239] As is known in the art, glass produced by the float glass process has a “tin side” that is in contact with molten tin during its formation and an “air side” that is opposite the tin side. It is well known in the art that the tin side has lower strength because it comes into contact with the conveyor rollers when it is transported from the float through an annealing furnace to be subsequently cut into sheets.

[0240] As discussed in "Acta Materiala Vol. 59, No. 4, pp. 1790-1799 (2011)," when measured from the air side or the tin side, a subcritical crack cluster that affects the strength of the glass is formed, and the strength measurement on the tin side shows a lower strength.

[0241] In the test of ten sets of 240mm×240mm samples, the strength of the relative surfaces was tested by measuring the strength by applying a load from the air side or the tin side.

[0242] Referring to Table 2, sample groups A1 and A2 are control groups used to determine the baseline strength of transparent float glass sheets, measured from the air side or the tin side.

[0243] Sample groups B1 and B2 are annealed glass sheets (like sample groups A1 and A2), which are treated with powder and then their strength is measured from the tin side or the air side.

[0244] Sample groups C1 and C2 are similar to sample groups B1 and B2, but the difference is that after being treated with test powder, the samples were heat-treated by raising the glass temperature from ambient conditions (about 20°C) to about 650°C, and then cooling it to ambient conditions with suitable air to simulate the heat distribution experienced by the glass sheet during the glass forming process (such as gravity sag or bending process).

[0245] Samples D1 and D2 are pre-annealed glass sheets, which were then heat-treated as described above for samples C1 and C2.

[0246] Sample groups F1 and F2 are the same as sample groups D1 and D2, but after a suitable air cooling step to ambient conditions, the samples in the sample groups are treated with powder in the same manner as sample groups B1, B2 and C1, C2.

[0247] Sample groups C1 and C2 were prepared to evaluate the effect of powder treatment on the strength of glass sheets prior to the heat treatment step, while sample groups F1 and F2 were prepared to evaluate the effect of powder treatment on the strength of glass sheets subsequently after the heat treatment step.

[0248] Samples treated with powder are prepared as follows. For each glass sheet in a specific sample group to be treated with powder, 1g of powder is placed at the center of the main surface to be treated. The powder is evenly spread over a circular area with a diameter of approximately 100mm centered on the center of the glass sheet. The powder is applied to the main surface of the glass sheet using a pressure of approximately 0.5N, moving in a spiral direction from the center of the glass sheet outwards to the periphery of the 100mm circular area and back to the center, so that the powder is evenly spread over the entire circular area. Each spiral movement from the center to the periphery of the circular area takes 10 seconds, and the contact area with the glass surface is approximately 1cm². 2 Use rubber tools.

[0249] The heat-treated samples were measured using a GASP surface stress measuring device, such as those commercially available from Strainotics (www.strainoptics.com) and Ayrox (www.ayrox.com). The GASP surface stress measurements showed a surface compressive stress of approximately 14 MPa to 17 MPa. That is, compared to the annealed glass samples, the heat-treated samples exhibited an increase in surface compressive stress of approximately 14 MPa to 17 MPa.

[0250] Surface damage caused by processing the tin or air side (sometimes referred to as the non-tin side) of each glass sheet is invisible to the naked eye. The damage can be seen using a microscope, and scratches can be seen using an Olympus SZX-12 optical microscope with a 1.6x objective lens at a setting of 40. Some of the observed scratches may have already been present on the surface of the glass sheet before powder treatment. The observed scratches are longer than 100 μm (typically less than 1000 μm) and less than 5 μm wide.

[0251] The haze of powder-treated glass sheets was measured using a BYK Hazegard Plus spectrometer in transmission mode and a Perkin-Elmer λ1050 spectrometer in total / diffuse transmission and reflectance modes. The results were compared with a control sample that was not powder-treated. No discernible difference was found between the control sample and the powder-treated glass sheets; the difference was within the measurement error range. The powder-treated glass sheets may exhibit an increase in haze, preferably less than 5% of the increase seen in the control sample.

[0252] Strength measurements were performed using an Instron 5985 materials testing system equipped with an ISO 1288-5 R60 ring-on-ring test apparatus. In each case, the samples were tested at a stress rate of 2 MPa / s until failure, and the maximum load and failure location were recorded. The number of tests performed on each sample group is listed in Table 2.

[0253] In Table 2, “Feature Strength” provides a measure of the location of the Weibull distribution, and “Weibull Modulus” is a measure of the variability of Weibull data.

[0254] As shown in Table 2, the strength of sample group A1 (141.8 MPa) is higher than that of sample group A2 (100.7 MPa), indicating a difference in glass strength between the air side and the tin side of the glass sheet manufactured using the float glass process. As mentioned above, after the glass sheet is formed, the tin side comes into contact with the conveyor rollers, which introduces subcritical cracks on the tin side of the float glass sheet, thereby reducing the glass strength.

[0255] As shown in Table 2, when the powder was applied to the annealed glass sheets (sample groups B1 and B2), the air-side glass strength decreased by approximately 50%, while the tin-side strength decreased by approximately 30%. The lower decrease in tin-side strength may be due to the already lower initial strength of the tin side.

[0256] The annealed samples that were subsequently heat-treated (sample groups D1 and D2) showed an increase in glass strength of approximately 50-60 MPa (compared to sample groups A1 and A2).

[0257] When the annealed glass sheets are heat-treated glass and then powder-treated (sample groups F1 and F2), they exhibit reduced strength compared to annealed glass sheets that are heat-treated but not powder-treated (sample groups D1 and D2). The Weibull modulus also increases.

[0258] The strength reduction of sample groups F1 and F2 differed from that of their corresponding sample groups B1 and B2, possibly because sample groups F1 and F2 had higher initial strength before powder treatment. The strength of sample groups F1 and F2 was approximately 15 MPa higher than that of their corresponding sample groups B1 and B2.

[0259] The effect of powder-treated glass sheets and heat-treated powder-treated glass sheets (sample groups C1 and C2) is that, compared with heat-treated annealed glass sheets (sample groups D1 and D2) without the intermediate treatment step of powder treatment, the strength of the glass sheets is reduced to a level comparable to that of annealed glass sheets (sample groups A1 and A2), but with a slightly narrower strength distribution (increased Weibull modulus).

[0260] To evaluate the effect of using powder-treated glass sheets, a vehicle windshield was manufactured, wherein at least one glass sheet of the vehicle windshield was powder-treated as described above.

[0261]

[0262] Table 2

[0263] Vehicle windshields were constructed with the configurations shown in Table 3. Each vehicle windshield consisted of a pair of initially pressed, bent transparent soda-lime silica glass sheets (2.1 mm thick) stacked together using 0.76 mm thick PVB sheets. Conventional lamination conditions were used, and each vehicle windshield was prepared using the same lamination conditions. Prior to lamination, the bent glass sheets underwent powder treatment. This corresponds to how the samples in sample group F1 or F2 were treated before strength measurements were performed, as shown in Table 2.

[0264]

[0265] Table 3

[0266] Vehicle windshields are manufactured by first bending glass sheets to become the inner and outer panels. As is conventional in the prior art, the glass sheet to become the outer panel is the exterior of the vehicle windshield to which the windshield is installed (or intended to be installed); while the inner panel is the interior of the vehicle windshield to which the windshield is installed (or intended to be installed). See reference. Figure 1 The outer panel of the laminated window glass 1 corresponds to the first glass sheet 3, while the inner panel of the laminated window glass 1 corresponds to the second glass sheet 7.

[0267] Returning to the embodiments in Table 3, using conventional bending methods, such as those described in EP0398759A2 or WO2004 / 085324A1, each glass sheet was bent (commonly referred to as "forming"). The bent glass sheets were then stacked together using PVB sheets with a thickness of 0.76 mm to produce the samples in Table 3.

[0268] The samples in sample group W1 are comparative, in which neither the inner nor outer plates were treated with powder.

[0269] The glass sheets used to manufacture the samples in sample group W2 were formed using the same bending process as those used to form the samples in sample group W1. However, before assembling the bent glass sheets to manufacture the final windshield, the surface of the outer panel was treated with the aforementioned powder, which would face the PVB sheet in the final laminated windshield (commonly referred to as surface two). No other glass surfaces were treated with this powder.

[0270] The glass sheets used to manufacture the samples in sample group W3 are formed using the same bending process as those used to form the samples in sample group W1. However, before assembling the bent glass sheets to manufacture the final windshield, the surface of the outer panel, which will face the PVB sheet in the final laminated windshield (commonly referred to as surface two), is treated with the aforementioned powder (the same as in sample group W2). However, the surface of the inner panel, which does not face the PVB sheet in the final laminated windshield (commonly referred to as surface four), is also treated with the aforementioned powder.

[0271] The glass sheets used to manufacture the samples in sample group W4 were formed using the same bending process as those used to form the samples in sample group W1. However, before assembling the bent glass sheets to manufacture the final windshield, the inner surface of the PVB sheet not facing the final laminated windshield (commonly referred to as surface four) was powder-treated with the aforementioned process. No other glass surfaces were powder-treated.

[0272] In the above embodiments, surface one is a convex surface, surface two is a concave surface, surface three is a convex surface, and surface four is a concave surface.

[0273] Powder preparation involves applying 1g of powder to a portion of the surface of a curved glass sheet, which will be the test impact location for the HIC test. Using a rubber tool, spread 1g of test powder evenly over a 50mm x 50mm square area with approximately 0.5N of pressure. Cover the square area with the test powder applied linearly and parallel over approximately 5 seconds, for a total preparation time of approximately 60 seconds. The square area is formed with the prepared area centered on the impact location required for the HIC test.

[0274] After treatment with the test powder, the glass sheet is washed with water to remove any test powder from the glass sheet, otherwise the powder may end up remaining in the final laminated window glass.

[0275] The particle size distribution of the powder can also help remove the powder from the glass sheet after treatment. Even if only one surface of the glass sheet is treated with powder, both surfaces of the glass sheet can be cleaned.

[0276] In the samples of sample groups W1, W2, W3, and W4, surfaces one and three are the tin sides of the glass sheets used for the outer and inner layers. Since the heat-treated sheets have similar strengths, referring to sample groups F1 and F2 (and Table 2), similar results are expected if surface one is tin-side and surface three is air-side; or if surface one is air-side and surface three is tin-side; or if surface one is air-side and surface three is air-side.

[0277] To determine the HIC value of the windshield, HIC tests were conducted at grid locations A, 12, +2 with an impact speed of 40 km / h, using the procedure described in EURO-NCAP Vulnerable Road User Test Protocol version 9.0.2. The header format used to determine the HIC value is as described in UN Regulation No. 127 (E / ECE / 324 / Rev.2 / Add.126 / Rev.2) Annex 4.

[0278] Referring to sample groups B1, B2 and F1, F2 in Table 2, the increased Weibull modulus indicates less change in strength distribution after the glass sheet has been powder-treated. Unbound by theory, this could help reduce the overall HIC value of vehicle windshields treated with this powder, as areas on the glass sheet surface are unlikely to have above-average strength.

[0279] The HIC values ​​of the vehicle windshields in sample groups W1, W2, W3 and W4 are shown in Table 4 below.

[0280]

[0281] Table 4

[0282] For vehicle windshields, a HIC value below 700, preferably below 650, is desirable. Sample groups W3 and W4 have an average HIC value below 700. For sample group W3, the HIC value is consistently less than 700, and the HIC value of the vehicle windshields shows almost no variation in this sample group.

[0283] Similar behavior is expected by treating areas of different sizes on surfaces two and / or four. For example, the treated area may be less than 80% of the area of ​​the corresponding main surface of the glass sheet and / or the treated area may be greater than 10% of the area of ​​the corresponding main surface of the glass sheet. A larger percentage of powder-treated surfaces two and / or four increases the area of ​​the vehicle windshield with reduced strength (and therefore a lower HIC value), thereby helping to reduce potential injury to pedestrians whose heads may strike different parts of the vehicle windshield.

[0284] Figure 4 A vehicle including a windshield 100 manufactured according to the present invention is shown. The windshield 100 is basically as described above. Figure 1 and 2 As stated above.

[0285] The windshield 100 has a transparent area defined by an upper edge DG; a right edge FG; a lower edge EF; and a left edge DE. Inside the upper, right, lower, and left edges is a treated area 104. The treated area is defined by the upper edge D'-G'; the right edge F'-G'; the lower edge E'-F'; and the left edge D'-E'. The interior of the treated area surface 4 of the windshield has been powder-treated with the type described above. The treated area 104 is not visible to the naked eye and forms part of the transparent area 102. Outside the treated area 104, the windshield surface 4 is not powder-treated.

[0286] The processed area 104 is approximately 75% of the entire perspective area 102.

[0287] In this embodiment, surface two is also treated with powder, which may be the same powder used to treat surface four.

[0288] Surface one and / or surface three of the windshield 100 are also within the scope of this invention. The treated area of ​​each main surface may be the same or different.

[0289] It can handle any combination of surface one, surface two, surface three, and surface four.

[0290] By including powder-treated glass sheets in the windshield 100, the strength of the glass sheets is reduced, which in turn reduces the strength of the windshield 100. If a pedestrian impacts the windshield 100 and comes into contact with its surface, the windshield is more likely to break due to the powder treatment. The glass sheets can be treated before being laminated onto another window glass material sheet, particularly a glass sheet, to create laminated window glass. Alternatively or supplementarily, the glass sheets can be powder-treated after being laminated onto the window glass material sheet, although this is only possible for the exposed surfaces of the windshield.

Claims

1. A method for reducing the strength of a first glass sheet, the first glass sheet having a first main surface and a second opposing main surface; The method includes: Processing steps, The processing steps include treating a portion of the first main surface of the first glass sheet with a first powder to reduce the strength of the first glass sheet; The first powder contains particles containing aluminosilicate glass.

2. The method of claim 1, wherein the aluminosilicate glass comprises pumice or basalt.

3. The method according to claim 1 or 2, wherein the aluminosilicate glass has (by weight) a composition comprising: 40-75% SiO2, 5-20% Al2O3, 0-10% Na2O, 0-10% K2O, 0-15% Fe2O3, and 0-20% CaO.

4. The method according to any one of the preceding claims, wherein the aluminosilicate glass has (by weight) a composition comprising: 55-75% SiO2, 5-15% Al2O3, 0-10% Na2O, 0-10% K2O, 0-10% Fe2O3, and 0-10% CaO.

5. The method according to any one of the preceding claims, wherein the aluminosilicate glass has (by weight) a composition comprising: 70-75% SiO2, 10-15% Al2O3, 2-7% Na2O, 2-7% K2O, and 0.5-3.5% Fe2O3.

6. The method according to any one of the preceding claims, wherein the aluminosilicate glass has (by weight) a composition comprising: 71-75% SiO2, 10-14% Al2O3, 2-6% Na2O, 2-6% K2O, 0.5-2.5% Fe2O3 and 0-1% CaO.

7. The method according to any one of the preceding claims, wherein the particles have a particle size distribution, the particle size distribution having: Average particle diameter from 1 μm to 250 μm; and Median particle diameter greater than 5 micrometers.

8. The method according to claim 7, wherein the median particle diameter of the particle size distribution of the first powder is not greater than 100 μm.

9. The method according to claim 7 or claim 8, wherein the particle size distribution of the first powder has at least one of the following: D10 greater than 1 μm, D10 not greater than 20 μm; D90 greater than 50 μm; a span defined as (D90-D10) / D50 between 0.5 and 15; D90-D10 of at least 30 μm; and D90-D10 of at most 400 μm.

10. The method according to any one of the preceding claims, wherein the particles have a Vickers hardness of greater than 5.2 GPa, preferably greater than 5.6 GPa, more preferably greater than 5.8 GPa, and even more preferably greater than 6 GPa.

11. The method according to any one of the preceding claims, wherein the first powder is applied to the first main surface of the first glass sheet using a powder applicator, preferably wherein the powder applicator comprises at least one of a cloth, a brush, a scraper, and a roller.

12. The method according to any one of the preceding claims, wherein during the processing step, a fluid carrier is used to guide the first powder to the first main surface of the first glass sheet, preferably wherein the fluid comprises a gas, such as nitrogen or air; or a liquid such as water.

13. The method according to any one of the preceding claims, wherein when the first glass sheet is treated with the first powder, a liquid is used in the processing step.

14. The method according to any one of the preceding claims, wherein the second main surface of the first glass sheet is treated with a second powder, the second powder having a composition and comprising particles having a particle size distribution, preferably wherein the particle size distribution of the second powder is the same as the particle size distribution of the first powder, and / or wherein the composition of the second powder is the same as the composition of the first powder.

15. The method according to any one of the preceding claims, wherein the first glass sheet is a soda-lime silicate glass having a composition comprising (by weight) the following: SiO2 69-74%; Al2O3 0-3%; Na2O 10-16%; K2O 0-5%; MgO 0-6%; CaO 5-14%; SO3 0-2%; and Fe2O3 0.005-2%; and / or wherein the first glass sheet has a thickness between 1 mm and 5 mm.

16. The method according to any one of the preceding claims, wherein the first glass sheet is produced by a float glass process, and wherein the first primary surface of the first glass sheet is tin-side, and the second primary surface of the first glass sheet is air-side.

17. The method according to any one of the preceding claims, wherein the first glass sheet is a laminated window slab, the laminated window slab comprising the first glass sheet joined to a window slab material sheet by an interlayer structure comprising at least one adhesive interlayer material sheet, the laminated window slab having an exposed main surface, and wherein the exposed main surface comprises a first main surface of the first glass sheet, preferably wherein the exposed main surface of the laminated window slab is surface one or surface four of the laminated window slab.

18. A method for manufacturing laminated window glass, comprising the following steps: (i) Providing a first glass sheet having a first main surface and a second opposing main surface; (ii) Using the method according to any one of claims 1 to 16 to reduce the strength of the first glass sheet; as well as (iii) The first glass sheet is laminated onto the window glass sheet using an interlayer structure comprising at least one adhesive interlayer material sheet; The first main surface of the first glass sheet faces the intermediate layer structure, or the second main surface of the first glass sheet faces the intermediate layer structure.

19. The method of claim 18, wherein step (ii) is performed before step (iii), and wherein after step (iii), the first main surface of the first glass sheet faces the intermediate layer structure.

20. The method of claim 19, wherein the first primary surface of the first glass sheet is surface two or surface three of the laminated window glass.

21. The method according to any one of claims 18-20, wherein the second main surface of the first glass sheet is treated with a second powder having a composition and comprising particles having a particle size distribution, wherein the second main surface of the first glass sheet is treated before or after step (iii).

22. The method of claim 18, wherein step (ii) is performed before step (iii), and wherein after step (iii), the second main surface of the first glass sheet faces the intermediate layer structure.

23. The method of claim 22, wherein the first primary surface of the first glass sheet is surface one or surface four of the laminated window glass.

24. The method according to claim 22 or 23, wherein prior to step (iii), the second main surface of the first glass sheet is treated with a second powder having a composition and comprising particles having a particle size distribution.

25. The method according to claim 21 or 24, wherein the second main surface of the first glass sheet is treated with the second powder during step (ii).

26. The method according to any one of claims 18 to 25, wherein the laminated window glass is a vehicle windshield.

27. The method of claim 26, wherein the vehicle windshield has a HIC value of less than 700, preferably less than 650.

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