Method for recycling glass

Abstract

A glass recycling method includes positing the glass in a chamber, irradiating surfaces of the glass with a laser over a laser irradiation time, introducing an acidic solution to the chamber and exposing the glass to the acidic solution over a first exposure time, introducing an alkaline solution to the chamber and exposing the glass to the alkaline solution over a second exposure time, and vibrating and rotating the chamber during the laser irradiation time, the first exposure time, and the second exposure time.

Description

SP24-262METHOD FOR RECYCLING GLASSCROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of priority under 35 U.S.C. § 119 of U.S. Provisional Application Serial No. 63 / 716326 filed on November 5, 2024, the content of which is relied upon and incorporated herein by reference in its entirety.FIELD

[0002] The present disclosure relates generally to methods for recycling glass and more specifically to methods for recycling glass manufactured for use in electronic devices.BACKGROUND

[0003] In the production of glass articles, such as glass sheets used for liquid crystal display thin film transistor (LCD-TFT) applications, waste glass can be generated. It is desirable to recycle such waste glass in order to minimize its environmental impact. However, such waste glass can include films, seals, and other forms of contamination, the removal of which can add complexity and expense to the recycling process. Accordingly, there is a continuing need for improved methods of recycling such glass.SUMMARY

[0004] Embodiments disclosed herein include a method of recycling glass. The method includes positioning the glass in a chamber. The method also includes irradiating surfaces of the glass in the chamber with a laser over a laser irradiation time. In addition, the method includes introducing an acidic solution to the chamber and exposing the glass to the acidic solution over a first exposure time. The method also includes introducing an alkaline solution to the chamber and exposing the glass to the alkaline solution over a second exposure time. In addition, the method includes vibrating and rotating the chamber during the laser irradiation time, the first exposure time, and the second exposure time.

[0005] Additional features and advantages of the embodiments disclosed herein will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the disclosed embodimentsSP24-262 as described herein, including the detailed description which follows, the claims, as well as the appended drawings.

[0006] It is to be understood that both the foregoing general description and the following detailed description present embodiments intended to provide an overview or framework for understanding the nature and character of the claimed embodiments. The accompanying drawings are included to provide further understanding and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments of the disclosure, and together with the description serve to explain the principles and operations thereof.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 is a schematic view of example forms of waste glass in an LCD panel fabrication process;

[0008] FIG. 2 is a schematic perspective side view of an example sample of waste panel glass;

[0009] FIG. 3 is a schematic perspective side view of an example sample of TFT glass;

[0010] FIG. 4 is a schematic perspective side view of an example sample of CF glass;

[0011] FIG. 5 is a schematic perspective side view of an example laser irradiation of the sample of FIG. 2;

[0012] FIG. 6 is a schematic perspective side view of an example laser irradiation of the sample of FIG. 3;

[0013] FIG. 7 is a schematic perspective side view of an example laser irradiation of the sample of FIG. 4;

[0014] FIG. 8 is a schematic perspective side view of exemplary samples subsequent to a laser irradiation step and prior to chemical treatment steps;

[0015] FIG. 9 is a schematic perspective side view of a chamber containing waste glass of exemplary samples during a laser irradiation step;

[0016] FIG. 10 is a schematic perspective side view of a chamber containing waste glass of exemplary samples during an acid treatment steps;

[0017] FIG. 11 is a schematic perspective side view of a chamber containing waste glass of exemplary samples subsequent to alkaline treatment steps;

[0018] FIG. 12 is a schematic perspective side view of exemplary samples subsequent to acid, alkaline and neutralization treatment steps;SP24-262

[0019] FIG.13 is a schematic perspective side view of exemplary samples in a chamber containing polishing media;

[0020] FIG. 14 is a schematic perspective view of residue removed by polishing media; and

[0021] FIG 15 is a schematic perspective view of an exemplary sample after a recycling treatment.DETAILED DESCRIPTION

[0022] Reference will now be made in detail to the present preferred embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts. However, this disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[0023] Ranges can be expressed herein as from “about” one particular value, and / or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, for example by use of the antecedent “about,” it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0024] Directional terms as used herein - for example up, down, right, left, front, back, top, bottom - are made only with reference to the figures as drawn and are not intended to imply absolute orientation.

[0025] Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order, nor that with any apparatus specific orientations be required. Accordingly, where a method claim does not actually recite an order to be followed by its steps, or that any apparatus claim does not actually recite an order or orientation to individual components, or it is not otherwise specifically stated in the claims or description that the steps are to be limited to a specific order, or that a specific order or orientation to components of an apparatus is not recited, it is in no way intended that an order or orientation be inferred, in any respect. This holds for any possible non-express basis for interpretation, including: matters of logic with respect to arrangement of steps, operational flow, order of components, or orientation of components;SP24-262 plain meaning derived from grammatical organization or punctuation, and; the number or type of embodiments described in the specification.

[0026] As used herein, the singular forms "a," "an" and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a” component includes aspects having two or more such components, unless the context clearly indicates otherwise.

[0027]

[0028] Exemplary methods of recycling LCD panel glass usually comprise panel deconstruction followed by polishing and exposure chemicals to remove films. However, once broken panels become irregular pieces, planar polish becomes impractical. In some processes, chemical dipping is applied to remove films. However, the presence of organic compounds such as resins, polymer coatings, black matrix materials, and sealants tend to block or decrease the chemical reaction of metals, oxides, and nitrides on the glass surface. Meanwhile, nitrides tend to be retained after exposure to common acids and / or alkaline solutions, and while these may be removed by grinding and polishing, such may be impractical when applied to waste glass with irregular shapes. Embodiments disclosed herein combine thermal, mechanical, and chemical steps to treat waste glass with irregular shapes and sizes, enabling the complete removal of foreign material in order to generate waste glass with impurity levels similar to newly formed glass.

[0029] FIG 1 shows an exemplary liquid crystal display (LCD) panel fabrication process. An LCD panel was constructed with thin film transistor (TFT) glass 2 and color filter (CF) glass 4 comprising different patterned TFT films 3 and CF films 5 deposited on glass 1. The TFT glass 2 and CF glass 4 can then be sandwiched together with sealant 6, for example, a UV cured resin. In order to increase manufacturing utilization, a large mother panel sheet, intended to contain multiple panels, may be cut into a plurality of smaller panels 7 after assembly. In such processes, waste glass material may be generated, such as, for example, in TFT and CF processes and / or following the integration of glass sheets into LCD panels (including related cutting processes), wherein a variety of organic and / or inorganic materials may be deposited on the waste glass sheets. Such waste glass material may, for example, include TFT glass 2, CF glass 4, waste panel glass 7, and trimmed glass 8.

[0030] FIG. 2 shows a schematic perspective side view of an example sample of waste panel glass 7. Waste panel glass 7 sandwiches TFT films 3, CF films 5, and sealant 6 and includes TFT glass 2 and CF glass 4.SP24-262

[0031] FIG. 3 shows a schematic perspective side view of an example sample of TFT glass 2. TFT glass 2 includes metal fdms 3A, oxide fdms 3B, and nitride fdms 3C on the glass 1.

[0032] FIG. 4 shows a schematic perspective side view of an example sample of CF glass 4. CF glass 4 includes red / green / blue (R / G / B) color resins 5A, black matrix 5B, and oxide films 5C.

[0033] Waste panel glass 7 of FIG. 2 may contain similar materials and / or layers as trimmed glass 8 of FIG. 1. Such materials and / or layers may, for example, include metal and / or oxide films, such as indium tin oxide (ITO) films, silicon nitride films, silicon oxide films, as well as copper, aluminum, molybdenum, and / or titanium films. In CF glass, such materials may, for example, include a variety of organic films and / or resins, which may, for example, take the form of black matrix materials, polarizers, sealants, tapes, and / or adhesives.

[0034] Embodiments disclosed herein may include waste glass samples comprising any configuration of one or more of such materials and / or layers. For example, glass 1 of TFT glass 2 and / or CF glass 4 may comprise Coming® Eagle XG® glass. Metal layer 3 A may comprise copper, oxide layer 3B may comprise silicon oxide and ITO, and nitride layer 3C may comprise silicon nitride. Organic layers may comprise R / G / B resin 5A, black matrix 5B, and ITO oxide layer 5C. When recycling waste glass, it is desirable to remove as many of these materials and / or layers as possible in an efficient and cost-effective manner.

[0035] FIG. 5 shows a schematic perspective side view of an example laser irradiation of waste panel glass 7 of FIG. 2. Laser irradiation of waste panel glass 7 includes directing a laser 10 from a laser source 11 onto sealant 6A. Such irradiation can cause vaporization of sealant 6A. Meanwhile, suction device 12 can carry away material removed from sealant 6A. After removal of sealant 6A, TFT glass 2 can be separated from CF glass 4. A remnant of sealant 6A may remain on glass, which can be removed in subsequent processing steps as described herein.

[0036] FIG. 6 shows a schematic perspective side view of an example laser irradiation of TFT glass 2 of FIG. 3. Laser irradiation of TFT glass 2 includes directing a laser 10 from a laser source 11 onto a surface of TFT glass 2. In this treatment, heat 13 can cause metal layer 3 A melt and partially vaporize to form voids 13A while, at the same time, imparting thermal cracks 13B, 13C, and 13D, into oxide layer 3B and nitride layer 3C.

[0037] FIG. 7 shows a schematic perspective side view of an example laser irradiation of CF glass 4 of FIG. 4. Laser irradiation of CF glass 4 includes directing a laser 10 from a laser source 11 onto a surface of CF glass 4. Heat 13 of laser irradiation can cause R / G / B resins 5A and black matrix layer 5B vaporize while, at the same time, imparting thermal cracks 14A,SP24-26214B and 14C, into ITO layer 5C. Meanwhile, suction device 12 can carry away material from vaporization of 5A and 5B.

[0038] FIG. 8 shows a schematic perspective side view of a sample 15 (which can include TFT glass 2, CF glass 4, and / or waste panel glass 7 of FIGS. 5, 6, and 7) subsequent to a laser irradiation step and prior to chemical treatment steps. As can be seen from FIG. 8 in comparison to FIG. 5, organic layers include sealant 6, R / G / B resins 5A and black matrix 5B has been removed (e.g., vaporized) from CF glass 4. In addition, substantial amounts of metal layer 3A have been removed and oxide layer 3B and nitride layers 3C have been partially removed from TFT glass 2 (e.g., as a result of the thermal cracking described with reference to FIG. 6). These cracks will become paths for chemicals to penetrate layers 3B and layers 3C to react with metal layer 3 A in following chemical treatment steps. In some conditions, a portion of sealant 6A may remain on sample 15 as shown in FIG. 8.

[0039] FIG. 9 shows a schematic perspective side view of a chamber 17 containing TFT glass 2, CF glass 4, and waste panel glass 7 during a laser irradiation step. Chamber 17 includes movement mechanism 18A and vibration mechanism 18B which can cause chamber 17 to vibrate and / or rotate in accordance with methods known to persons having ordinary skill in the art. Similar to FIGS. 5-7, laser irradiation of TFT glass 2, CF glass 4, and / or waste panel glass 7 includes directing a laser 10 from a laser source 11 onto one or more surfaces of samples. Meanwhile, suction device 12 can carry away material removed from samples. In certain exemplary embodiments, suction device 12 can comprise a vacuum source.

[0040] In certain exemplary embodiments, the laser 10 comprises a pulsed fiber laser as known to persons having ordinary skill in the art. In certain exemplary embodiments, the laser 10 can be passed through abeam expanding collimator, an X-Y scanning galvanometer, one or more mirrors, and / or one or more lenses (e.g., field lenses) in accordance with laser operation methods known to persons having ordinary skill in the art. In certain exemplary embodiments, a power of laser 10 ranges from about 50 watts to about 300 watts.

[0041] In certain exemplary embodiments, chamber 17 is rotated at a rotation speed ranging from about 5 rotations per minute (rpm) to about 10 rpm. In certain exemplary embodiments, chamber 17 is vibrated at a frequency of about 60 Hz to about 120 Hz.

[0042] The combined operation of laser 10 and rotation and / or vibration of chamber 17 can enable increased laser irradiation of surface areas of TFT glass 2, CF glass 4, and / or waste panel glass 7 having irregular shapes. For example, the combined operation of laser 10 and rotation and / or vibration of chamber 17 can enable laser irradiation of surface areas ofSP24-262 samples at a variety of different angles, which can result in increased removal of materials present on those surfaces. For example, such irradiation can cause vaporization of sealant 6A as shown in FIG.5, vaporization of organic layers of R / G / B resin 5A and black matrix 5B as shown in FIG. 7 and destroy metal layer 5 A to form voids as shown in FIG. 6 while, at the same time, imparting thermal cracks 13B, 13C, and 13D, into any oxide layer 3B or nitride layer 3C. Such voids 13A in metal layer 3A can cause delamination of oxide layers 3B and nitride layers 3C from samples. Meanwhile, thermal cracks 13B, 13C, and 13D can in turn, facilitate additional removal of oxide layer 3B and nitride layers 3C in downstream chemical treatment steps.

[0043] In certain exemplary embodiments, irradiating surfaces of samples via combined operation of laser 10 and rotation and / or vibration 19 of chamber 17 can occur for a laser irradiation time ranging from 30 minutes to 1 hour. In some cases, laser irradiation steps can be repeated after subsequent to chemical treatment steps.

[0044] FIG. 10 shows a schematic perspective side view of a chamber 20 containing samples 15 of FIG. 8 during an acid treatment step. As shown in FIG. 10, a pH meter 24 is used to monitor and / or control pH value, which in certain exemplary embodiments should be less than about 4.0 during acid treatment. Acid treatment can occur subsequent to a laser irradiation step and comprises introducing an acidic solution 23 to chamber 20. Acid treatment step includes vibrating 22 and / or rotating chamber 20 via movement mechanism 21A and vibration mechanism 2 IB.

[0045] In certain exemplary embodiments, acidic solution 23 comprises an acidic aqueous solution comprising at least one of hydrochloric acid (HC1), sulfuric acid (H2SO4) and / or nitric acid (HN03). For example, acidic solution 23 may comprise HC1 in a range of about 10% to about 37% by volume and may comprise H2SO4 in a range of about 10% to about 20% by volume, including embodiments in which pH value should is controlled to be less than 4. In certain exemplary embodiments, a temperature of acidic solution 23 may be less than about 55°C, such as from about 20°C to about 55°C.

[0046] In certain exemplary embodiments, chamber 20 is rotated at a rotation speed ranging from about 5 rotations per minute (rpm) to about 10 rpm. In certain exemplary embodiments, chamber 20 is vibrated at a frequency of about 60 Hz to about 120Hz. Such rotation and / or vibration can facilitate chemical reaction between materials still present on samples 15 (e.g., one or more metal layer 3A or oxide layer 3B or nitride layer 3C or ITO layers 5C).SP24-262

[0047] In certain exemplary embodiments, samples 15 of waste glass can be exposed to acidic solution 23 during rotation and / or vibration of chamber 20 over a first exposure time ranging from about 30 minutes to about 1 hour.

[0048] In certain exemplary embodiments, most metal layers 3 A of TFT glass 2 and ITO layers 5C of CF glass 4 can be completely removed after acid treatment. In addition, oxide layers 3B and nitride layer 3C of TFT glass 2 can be partially removed but can also delaminate from glass because metals layers 3A has been removed.

[0049] FIG. 11 shows a schematic perspective side view of a chamber 20 containing samples 15 of waste glass during an alkaline treatment step. Alkaline treatment step can occur subsequent to acid treatment step and comprises introducing an alkaline solution 25 to chamber. Alkaline treatment step includes vibrating 22 and / or rotating chamber 20 via movement mechanism 21A and vibration mechanism 2 IB. As shown in FIG. 10, a pH meter24 is used to monitor and / or control pH value, which in certain exemplary embodiments should be greater than about 10.0 during alkaline treatment.

[0050] In certain exemplary embodiments, alkaline solution 25 comprises an alkaline aqueous solution comprising sodium hydroxide (NaOH). For example, alkaline solution may comprise NaOH in a range of >10% NaOH with pH of at greater than about 10 and / or NaaPOr if need by volume. In certain exemplary embodiments, a temperature of alkaline solution 25 may be greater than about 50°C, such as from about 50°C to about 95 °C, and further such as from about 60°C to about 85°C.

[0051] In certain exemplary embodiments, chamber 20 is rotated at a rotation speed ranging from about 5 rotations per minute (rpm) to about 10 rpm. In certain exemplary embodiments, chamber 20 is vibrated at a frequency of about 60 Hz to aboutl20 Hz. Such rotation and / or vibration can facilitate chemical reaction between materials still present on samples 15 of waste glass (e.g., organic compound R / G / B resins 5A, black matrix 5B and Sealant 6A and other physical attached particles on glass surface).

[0052] In certain exemplary embodiments, samples 15 can be exposed to alkaline solution25 during rotation and / or vibration of chamber 20 over a second exposure time ranging from about 30 minutes to about 1 hour.

[0053] In certain exemplary embodiments, a rinse solution having a pH of about 7 may be introduced to chamber 20 between the first exposure time (in acidic solution) and the second exposure time (in alkaline solution). An exemplary rinse solution is water, such as deionized water. For example, acidic solution 23 of FIG. 10 may be first drained from chamber 20SP24-262 followed by introduction of rinse solution. Rotation and / or vibration of chamber 20 may continue during exposure of samples 15 to rinse solution.

[0054] In certain exemplary embodiments, a neutralizing solution having a pH of less than 7 may be introduced to chamber 20 of FIG. 10 after the second exposure time (in alkaline solution). An exemplary neutralizing solution is an organic acid, such as citric acid (C’eHsO?). For example, alkaline solution 25 may be first drained from chamber 20 followed by introduction of neutralizing solution. Rotation and / or vibration of chamber 20 may continue during exposure of samples 15 to neutralizing solution.

[0055] FIG. 12 shows a schematic perspective side view of sample 26, which is sample 15 subsequent to acid, alkaline, neutralization and clean steps. Residues 26A, including oxides and nitrides, may retain on the sample 26.

[0056] FIG. 13 shows a schematic perspective side view of samples 26 placed in a tumble chamber 27 filled with a liquid 30 comprising tumbling media 29. In certain exemplary embodiments, liquid 30 comprises water with a pH of about 7. Rotation and / or vibration 28 of chamber 27 may continue during vibration using methods known to person having ordinary skill in the art.

[0057] FIG. 14 shows residue 26A of FIG. 12 can be mechanically removed by tumbling media 29 of FIG. 13, wherein tumbling media 29 contacts and removes residue 26A from the surface.

[0058] FIG. 15 shows a schematic perspective side view of sample 32, wherein sample 32 is sample 15 of FIG. 8 subsequent to chemical treatment steps (e.g., treatment steps in acidic and alkaline solutions and tumbling). As can be seen from sample 32 in comparison to FIGS. 2-8, TFT films 3 and CF films 5 have been completely removed from glass substrate 1.

[0059] Embodiments disclosed herein include those in which performing the combination of laser irradiation steps, acid treatment steps, alkaline treatment steps, neutralization steps and tumbling steps results in removal of materials on waste glass (e.g., removal of organic layers 6, 5A and 5B, metal layer 3A, metal oxide layer 3B and 5C and nitride layer 3C as shown by comparing FIG. 16 with FIG. 2) such that the treated waste glass contains similar levels of those materials as found on pristine glass. For example, fresh samples of Coming® Eagle XG® glass were compared with treated recycled samples of Coming® Eagle XG® glass used in LCD-TFT applications for a variety of metallic contaminants using x-ray florescence (XRF) and induction coupled plasma mass spectrometry (ICP-MS) with the results shown in Table 1.

[0060] Table 1: Metallic contaminant levels on glass before and after treatmentSP24-262

[0061] As can be seen from Table 1, the treated waste glass had comparable levels of contaminants as fresh glass.

[0062] It will be apparent to those skilled in the art that various modifications and variations can be made to embodiment of the present disclosure without departing from the spirit and scope of the disclosure. Thus, it is intended that the present disclosure cover such modifications and variations provided they come within the scope of the appended claims and their equivalents.

Claims

SP24-262What is claimed is:

1. A method of recycling glass comprising: positioning the glass in a chamber; irradiating surfaces of the glass in the chamber with a laser over a laser irradiation time; introducing an acidic solution to the chamber and exposing the glass to the acidic solution over a first exposure time; introducing an alkaline solution to the chamber and exposing the glass to the alkaline solution over a second exposure time; and vibrating and rotating the chamber during the laser irradiation time, the first exposure time, and the second exposure time.

2. The method of claim 1, wherein the laser comprises a pulsed fiber laser.

3. The method of claims 1 or 2, wherein a power of the laser ranges from about50 watts to about 300 watts.

4. The method of claim 1, wherein the method comprises decomposing or vaporizing materials present on the glass, wherein at least one sample of the glass is oriented at a different angle as at least one other sample of the glass.

5. The method of any one of claims 1 to 4, wherein the acidic solution comprises at least one of hydrochloric acid (HC1), sulfuric acid (H2SO4), or nitric acid (HNO3).

6. The method of any one of claims 1 to 5, wherein the alkaline solution comprises sodium hydroxide (NaOH).

7. The method of any one of claims 1 to 6, wherein a temperature of the acidic solution is less than about 50°C and a temperature of the alkaline solution is greater than about 50°C.SP24-2628. The method of any one of claims 1 to 7, wherein the chamber is rotated at a rotation speed ranging from about 5 rotations per minute (rpm) to about 10 rpm during the laser irradiation time, the first exposure time, and the second exposure time.

9. The method of any one of claims 1 to 8, wherein the laser irradiation time, the first exposure time, and the second exposure time each range from about 30 minutes to about 1 hour.

10. The method of any one of claims 1 to 9, wherein a rinse solution having a pH of about 7 is introduced to the chamber between the first exposure time and the second exposure time.

11. The method of any one of claims 1 to 10, wherein a neutralization solution having a pH of less than about 7 is introduced to the chamber after the second exposure time.

12. The method of claim 11, wherein the neutralization solution comprises citric acid (CeHsO?).

13. The method of any one of claims 1 to 12, further comprising introducing a tumbling media to the chamber subsequent to the second exposure time, exposing the glass to the tumbling media over a tumbling time, and vibrating and rotating the chamber during the tumbling time.

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