EP-3307685-B1 - FOREHEARTH FRITS, PEARLS AND/OR CONCENTRATES FOR FLUORESCENCE

Inventors

• BODIN, Stephane, Francois Yves
• DUMAN, Yasin
• Darbouret, Benoit

Dates

Publication Date

20260506

Application Date

20160802

Claims (6)

1. A fluorescent glass frit, wherein the composition is as follows: 15-65 wt% SiO 2 0-5 wt% Al 2 O 3 3-25 wt% B 2 O 3 5-15 wt% Na 2 O 0-8 wt% CaO 5-65 wt% rare earth metal oxide 0-15 wt% Li 2 O, wherein the rare earth metal oxide is selected from the group consisting of europium oxide, samarium oxide, dysprosium oxide, terbium oxide, cerium oxide, and combinations of the foregoing.
2. A soda-lime glass further comprising the fluorescent glass frit of claim1.
3. A borosilicate glass further comprising the fluorescent glass frit of claim 1.
4. An opalescent glass further comprising the fluorescent glass frit of claim 1.
5. A pearl or concentrate comprising the fluorescent glass frit of claim 1.
6. The glass frit, pearl or concentrate of claims 1 to 5 wherein the glass frit, pearl or concentrate is devoid of all of nickel, chromium, lead and cadmium.

Description

BACKGROUND OF THE INVENTION 1. Field of Invention The present invention relates to the field of forehearth frits, pearls, and/or concentrates for use in glass compositions. In particular, the present invention provides a system of forehearth frits, pearls, and/or concentrates, in accordance with REACH and food migration specifications, that is capable of imparting a fluorescent effect to glass product by addition to a glass composition in the forehearth of a glass furnace, and a method of using the fluorescent effect system of forehearth frits, pearls, and/or concentrates. The invention further provides a glass composition for use in forming the fluorescence system or for use directly in a forehearth. 2. Description of Related Art Prior art shows that no method of imparting fluorescent effects to glass exists. Fluorescence is an effect usually used for paints, polymers such as polishes, or very technical items such as lasers or banknotes. The prior art documents US 2014/0037074, SU 1590455 A, JP 2005 011745 A, US 2012/126172 A, US 6 287 993 B, US 3996 627 B, US 4 102 805 B and US 3 522 190 B all discloses glass compositions similar to the one of the current invention. However, all of these compositions are different from the one of the current invention. BRIEF SUMMARY OF THE INVENTION Accordingly, methods to obtain fluorescent glasses via forehearth are sought. The present invention represents one such effort. Fluorescence is a light emission which follows an absorption of UV light or X-rays. Lasers can be used to provide the UV or X-ray irradiation. This emitted light is called luminescence and is visible only under exposure. In the following the glass frit which contains element(s) able to produce fluorescence in glass will be named "the fluorescent glass frit" and the glass pearl or concentrate which contains element(s) able to produce fluorescence in glass will be named "fluorescent forehearth concentrate or pearl." Collectively, these will be termed "fluorescent dyes" or simply "dyes." The manufacture of fluorescent glass in a forehearth of a furnace (manufacturing methods are not according to the current invention and only mentioned for illustrative purposes) may be undertaken by the addition of either: (i) a fluorescence enriched glass frit, or (ii) a fluorescence-imparting concentrate or pearl comprising a non-smelted compacted interspersion for addition to the molten glass in the forehearth of a glass furnace. The concentrate or pearl is added to a molten clear, colorless or colored base glass. The intentional addition of fluorescence-imparting oxides, glasses, concentrates or pearls to a molten base glass in the forehearth of a glass furnace is believed to be novel. Fluorescence can be imparted to, and observed in, various glasses such as soda-lime glasses, borosilicate glasses or opal glasses. In such processes, the fluorescent glass frit or fluorescent forehearth concentrate or pearl is added to the molten glass flowing through the forehearth of a furnace. Unlike mass production, the fluorescence-imparting compositions and processes of the invention make possible the manufacture of one or more fluorescent effect compositions and clear/colorless/colored glass compositions from a single melting furnace equipped with multiple forehearths. In the forehearth fluorescence imparting process, the fluorescent glass frit or fluorescent forehearth concentrate or pearl is metered into the molten base glass after the base glass flows from the refining zone or distributor of the furnace and into the forehearth. It can be added in combination with one or several colored usual frits, pearls or concentrates. Indeed, a fluorescent effect can be observed in a colored glass. The present invention provides a system of fluorescent forehearth frits, pearls and/or concentrates that can be quickly and completely dispersed and dissolved when added to the molten base glass of a forehearth furnace at conventional commercial molten glass temperatures. Accordingly, the system of frits, pearls and/or concentrates can be used at a lower loading (less than about 10 wt%, preferably less than 5 wt%, such as 0.1-5% or 1-4 %) in the final glass composition relative to the prior art. Use of the forehearth fluorescent effect frits, pearls and/or concentrates of the present invention leads to a uniform dispersion of fluorescent glass with the base glass obtaining a fluorescent effect. With these fluorescence-imparting compositions, the glass producer can also produce other heterogeneous effect like fluorescent stripes. The invention further provides methods of using the glass frits, concentrates or pearls, and a method for forming an agglomerated fluorescent effect concentrate or pearl. The current invention comprises the following item: A fluorescent glass frit, wherein the composition is as follows: 15-65 wt% SiO20-5 wt% Al2O33-25 wt% B2O35-15 wt% Na2O0-8 wt% CaO5-65 wt% rare earth metal oxide0-15 wt% Li2O, wherein the rare earth me