Classifications

• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C15/00—Surface treatment of glass, not in the form of fibres or filaments, by etching
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C2204/00—Glasses, glazes or enamels with special properties
  • C03C2204/08—Glass having a rough surface

Definitions

• the present invention relates to matt glass sheets, in particular acid- etched glass sheets, and to such glass sheets that may be used as floor covering.
• matt glass sheets we mean herein translucent glass sheets with a satin finish which diffuse light and may assure privacy.
• “Matt glass sheets” may preferably show at least one of the following properties: a luminous transmittance (LT) value of less than 90%, a haze value of more than 90% and/or a clarity value of less than 20% (all these values being measured on the acid -etched face of a clear glass sheet of 8 mm-thick).
• LT luminous transmittance
• Glass sheets according to this invention may have particular advantage for use as floor covering or for staircase steps, due to their anti-slip properties, in exterior and interior applications. They may also be used for example for decorative purpose, in furniture, wardrobes, in tables, shelves, in bathrooms or in shops displays.
• EP 937 689 A1 describes an alternative which consists in making holes in the glass and fill them in with a resin comprising grains of a hard material.
• matt acid-etched glass sheets are known, which may be used for floor applications. They are aesthetically pleasant and have the advantage, compare to clear glass, that what is under the flooring, e.g. concrete, is not visible.
• acid -etched glass sheets may be produced by controlled acid attack, during between 30 seconds and 15 minutes (depending on the acid solution used), on a surface of a pre-formed glass sheet.
• the acid attack produces a degree of surface roughness on the treated glass surface which results in reduced spectral reflection (due to greater diffusion of reflected light) and a fine matt appearance.
• This very fine surface roughness may be characterised by the combination of a Rz around 1 1 - 13 ⁇ m and a Rz/RSm around 0.14 - 0.17.
• RSm may vary between 60 and 100 ⁇ m.
• Rz and RSm are typical measures of surface roughness; the way to measure those values is explained hereunder.
• the present invention provides a glass sheet as defined by claim 1 .
• Dependent claims define preferred and/or alternative aspects of the invention.
• the acid -etched surfaces of glass sheets according to the invention have a surface roughness defined by:
• Rz greater than 12, preferably greater than 14, more preferably greater than 16 and less than 22, preferably less than 20, and
• Rz/RSm greater than 0.18, greater than 0.20, preferably greater than 0.21 , more preferably greater than 0.22 and less than 0.30, preferably less than 0.28, more preferably less than 0.26.
• Cut-off "use the whole selected data length"
• the present invention has particular advantages in relation to flooring or staircase steps, nevertheless it may also be used on shelves or shop displays, for example, on which the objects can not slip.
• only one face of the glass sheet may have a roughness in the range of the present invention.
• both faces of the glass sheet may be acid -etched.
• Glass sheets according to the invention may show RSm greater than 65, preferably greater than 70, more preferably greater than 72 ⁇ m and less than 90, preferably less than 85, more preferably less than 80 ⁇ m.
• glass sheets according to the invention when tested according to standard DIN 51130:2004-6, show anti-slip properties ranging from R9 to R11 ; preferably, they reach R11.
• R9, RI O and R11 are examples of applications for R9, RI O and R11 :
• Glass sheets according to the invention may preferably have L* (defined in the CIE L*a*b* system, for a clear glass sheet of 8 mm-thick, and measured on the acid-etched face of the glass sheet with a MINOLTA CM-2600d apparatus, with the following measurement parameters: illuminant C, 10° , SCI, white tile as background) of less than 72%, preferably less than 70%, more preferably less than 68%, and greater than 60%, preferably greater than 63%, more preferably greater than 65%. These values have to be compared with a conventional acid -etched glass which shows a L* value of around 73%. This lower L* value for the present ant-slip glass sheets may be explained by the change in roughness of the acid -etched surface.
• L* defined in the CIE L*a*b* system, for a clear glass sheet of 8 mm-thick, and measured on the acid-etched face of the glass sheet with a MINOLTA CM-2600d apparatus, with the following measurement parameters:
• Glass sheets according to the invention may preferably have at least one of the following properties: a luminous transmittance (LT) value of less than 90%, preferably less than 89% and greater than 84%, preferably greater than 86%, a haze value greater than 90%, preferably greater than 95%, more preferably greater than 98%, and a clarity value of less than 20% , preferably less than 10%, more preferably less than 7%, still more preferably less than 5%, and greater than 2%, preferably greater than 3%, more preferably greater than 4%, all these values being measured on the acid-etched face of a clear glass sheet of 8 mm-thick.
• LT luminous transmittance
• Clarity is a measure of the light that is scattered at small angles when passing through a glass sheet; haze is a measure of the light that is scattered at greater angles when passing through a glass sheet. All the measurements of haze and clarity referred to herein where made on a HAZE-GARD PLUS apparatus conform to the standard ASTM D-1003.
• the glass substrate used may be float glass of various thicknesses (between 1 .8 and 16.2 mm, for example). A thickness greater than 6 mm is preferred for floor applications.
• the glass sheet may be tempered and/or laminated; for shelves or displays it may be tempered.
• the present invention provides a floor covering as defined by claim 9 and a method, as defined in claim 10, for manufacturing glass sheets according to the invention.
• Acid -etched glass sheets according to the invention may advantageously be produced by controlled acid attack, using well-known acid-etching solutions commonly used in the manufacture of conventional acid-etched glass, during more than 5 minutes, preferably between 10 and 30 min (depending on the acid solution used) on a surface of a pre-formed glass sheet.
• the acid attack produces a degree of surface roughness on the treated glass surface, a texturing which results in anti-slip properties.
• the acid attack may be made in one or several steps.
• a sheet of clear float glass 8 mm-thick is acid-etched in a known manner, but during a longer time than for conventional acid-etched glass. In this case the duration of the acid attack was 25 minutes.
• the roughness of glass sheet was then measured by a Taylor- Hobson Talysurf analysis of surface roughness, as commonly used for analysing surface roughness.
• the analysis consists of arranging a fine stylus having a calibrated point in contact with the surface to be analysed and slowly displacing the stylus across the surface so as to record all variations in the altitude of the surface. The parameters cited above were used to carry out this analysis.
• Rz (also called Rtm) is the average of all of the values Rz1 , Rz2 .... etc. over the entire profile Rz1 is the greatest difference in altitude between the highest peak and the lowest valley over the first cut-off portion of the sample
• Rz2 is the greatest difference in altitude between the highest peak and the lowest valley over the second cut-off portion of the sample (and so on for Rz3)
• RSm also called Sm
• Sm is the average of the distance between each time the profile crosses the average line; it represents an indication of the average distance between the main peaks of the profile.
• the short range filter and long range filter are used to separate a characteristic measurement of surface roughness from an overall "waviness" of the sample and from very short wavelength effects.

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• Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Surface Treatment Of Glass (AREA)
• Laminated Bodies (AREA)

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• 2007
  • 2007-10-18 EP EP07821491A patent/EP2074072A2/de not_active Withdrawn
  • 2007-10-18 WO PCT/EP2007/061126 patent/WO2008046877A2/en not_active Ceased

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