Method for producing a glass container

Abstract

The present invention relates to a method for producing a glass container comprising the steps of: a. melting a solid vitrifiable mixture to obtain a molten vitrifiable mixture; b. feeding the molten vitrifiable mixture into a plurality of glass container forming machines through the respective feed channels; c. combining at least one recycled glass frit into the molten vitrifiable mixture in at least one of the feed channels, the frit being obtained from a vitrifiable mixture comprising recycled glass cullet and at least one fluxing agent; d. forming a glass container in said forming machines using the molten vitrifiable mixture from step c.

Description

METHOD FOR PRODUCING A GLASS CONTAINER FIELD OF THE INVENTION

[001] The present invention relates to a method for producing glass containers. In particular, the present invention relates to a method for producing a glass container using recycled glass cullet, especially post-consumer glass cullet (referred to as PCR cullet). BACKGROUND OF THE INVENTION

[002] As is known, the cycle for the production of a glass container essentially comprises the steps of: melting a vitrifiable solid mixture to obtain a molten mass, forming the molten mass to obtain the glass container, annealing the glass container and final finishing.

[003] The vitrifiable solid mixture is melted in melting furnaces, generally operating continuously, to which the components of the mixture are fed automatically. The mixture comprises virgin raw materials in powder form and additive materials (fluxes, stabilizing agents, coloring agents, decolorizing agents, refining agents, oxidizing agents, reducing agents, etc.).

[004] The vitrifiable liquid mixture obtained by melting passes from the melting furnace tank to a refining area (refiner) usually located within the same furnace – and from there, through a series of feed channels (pre-crucible), also called heat conditioning channels, to a respective series of forming machines, each of which can produce a final product with a different shape. The vessel exiting the forming machine undergoes an annealing heat treatment to eliminate the stresses generated in the glass during forming. Finally, in the finishing stage, the vessel finishing operations are carried out (cutting, decoration, etc.). Petition 870260013236, dated 11 / 02 / 2026, page 9 / 61 2 / 19

[005] In the field of glass container production, there is a constant commitment to using recycled glass cullet as a substitute, at least partially, for the virgin raw materials that feed into the melting stage.

[006] A common practice, for example, is the recovery of glass cullet generated in glass production plants, such as, for example, products rejected due to lack of quality requirements, production waste, etc. This glass cullet, also defined as post-industrial recycled cullet or PIR cullet, can come from the same production facility where it is recycled (internal PIR cullet) or from other facilities other than the one where it is recycled (external PIR cullet).

[007] In an attempt to further reduce the consumption of raw materials and energy in the production processes of glass containers, the recycling of glass cullet from the sorting of urban waste is also known, generally called post-consumer recycled cullet or PCR cullet.

[008] PCR cullet is advantageously recycled in plants for the production of coloured glass containers (e.g. green, brown or amber glass), where it can also be used in large quantities, for example, even as high as 60% to 80% by weight of the vitrifiable mixture subjected to melting.

[009] In the case of the production of containers for perfumery, cosmetics and the food sector, where a white and highly transparent glass is required, the recycling of PCR cullet, on the other hand, presents some critical problems that severely limit its reuse and, consequently, the possibility of marketing products that are more environmentally sustainable and that meet the concepts of the circular economy.

[0010] PCR shards actually consist of a mixture of glass Petition 870260013236, dated 11 / 02 / 2026, page 10 / 61 3 / 19 colored and white glass with a highly variable chemical composition and, in any case, substantially different from that of the glass used to manufacture said type of container. In particular, PCR cullet is characterized by the presence of high concentrations of coloring compounds, especially iron and chromium oxides, which impart a yellow-greenish color to the final container if introduced into the solid vitrifiable mixture subjected to fusion.

[0011] This undesirable color change can be controlled by adding glass decolorizing agents (e.g., Se, Co, or Er-based compounds) to the solid vitrifiable mixture subject to melting. The use of certain decolorizing compounds (e.g., rare earth oxides), however, in addition to reducing the environmental sustainability of the resulting glass products, negatively affects the transparency of the glass if added in large quantities. Furthermore, controlling the color of the glass through decolorizing compounds must take into account the compositional variations between different batches of PCR cullet used; this implies the need to constantly monitor the chemical composition of the glass during the production cycle.

[0012] An example of a process in which PCR shards are used together with virgin raw materials for the production of glass containers for the perfume and cosmetics industry is described in EP 3252021 A1.

[0013] Another critical factor that limits the recycling of cullet In the production of glass containers, PCR (polymer-recycled cullet) is characterized by the fact that, generally, a plurality of forming machines receive the molten glass mass fed from a single melting furnace. Therefore, if PCR cullet is fed into the solid vitrifiable mixture subjected to melting, the final containers that come out of the forming machines are made of glass with the Petition 870260013236, dated 11 / 02 / 2026, p. 11 / 61 4 / 19 same recycled raw material content, since it is not possible to feed each machine with a mass of molten glass with a predetermined content different from PCR cullet.

[0014] The inability to produce containers with different contents and types of recycled material represents a significant technical limitation, which restricts the flexibility of a production facility and prevents it from promptly meeting market demands. Currently, this restriction appears to be overcome only by installing multiple melting furnaces, each of which is fed a vitrifiable mixture containing a different proportion of PCR shards. This solution, however, is obviously difficult in terms of practical feasibility due to the installation costs involved. SUMMARY OF THE INVENTION

[0015] In consideration of the aforementioned state of the art, the applicant has set himself the main objective of providing a method for the production of glass containers that overcomes, at least in part, the disadvantages of the state of the art.

[0016] In particular, a specific objective of the present invention is to provide a method for the production, using different forming machines fed by the same melting furnace, of glass containers with a different content of recycled glass cullet, particularly PCR cullet, i.e., containers made of molten glass incorporating different proportions of glass cullet.

[0017] A second objective of the present invention is to provide a method for the production of glass containers, in particular for cosmetics and perfumery, which allows the recovery and recycling of glass cullet, so as to be more environmentally sustainable and respectful of the concepts of circular economy.

[0018] An additional objective of the present invention is to provide a Petition 870260013236, dated 11 / 02 / 2026, page 12 / 61 5 / 19 method for the production of glass containers that uses recycled glass cullet, particularly post-consumer glass cullet, as a partial replacement for virgin glass-forming raw materials.

[0019] The applicant has now verified that this objective and others, which will be better illustrated below, can be achieved by dosing a glass shard, in particular a PCR glass shard, in the form of a frit into the individual feed channels through which the liquid vitrifiable mixture flows from the melting furnace and which is fed into the forming machines.

[0020] The glass cullet is preliminarily converted into a recycled glass frit (hereinafter also referred to as just frit), which is a finely divided glass substance (e.g., granules or flakes) with a melting point lower than that of the initial glass cullet; the frit is then incorporated and homogenized into the vitrifiable molten mixture flowing in the feed channels.

[0021] According to a first aspect, therefore, the present invention relates to a method for the production of glass containers comprising the steps of: a. to melt a first solid vitrifiable mixture to obtain a first molten vitrifiable mixture; b. feeding the first molten vitrifiable mixture to a plurality of glass container forming machines through their respective feeding channels; c. combine at least one recycled glass frit with the first melted vitrifiable mixture in at least one of the feed channels, the frit being obtained from a second solid vitrifiable mixture comprising recycled cullet and at least one fluxing agent; d. forming a glass container in said forming machines using the molten vitrifiable mixture from step c. Petition 870260013236, dated 11 / 02 / 2026, p. 13 / 61 6 / 19

[0022] Recycled glass frit can be easily obtained by melting a vitrifiable solid mixture comprising cullet and at least one fluxing agent and subjecting the molten mixture to rapid cooling.

[0023] In one embodiment, the solid vitrifiable mixture used to prepare the frit may also contain a glass decolorizing compound to compensate for any coloration imparted by the addition of recycled glass frit to the molten vitrifiable mixture.

[0024] In another embodiment, the decolorizing agent can also be introduced into the molten vitrifiable mixture flowing in the feed channel in the form of a glass frit containing it, other than recycled glass frit.

[0025] Other process features according to the present invention are defined in dependent claims 2 to 12.

[0026] The addition of cullet in the form of a frit to one or more feed channels allows single-forming machines to be fed with a molten vitrifiable mixture with a different and predetermined content of cullet. With the method described herein, it is also possible to feed the feed channels with recycled glass frits with different chemical compositions from one another. The method according to the present description, therefore, increases the versatility of a glass container production plant, allowing a greater variety of recycled glass containers to be produced with the same melting furnace. The method also allows for reduced preparation times for a specific product batch, improving the plant's ability to quickly meet market demands. Furthermore, the manufactured products, being obtained from the recovery and recycling of waste material, meet criteria of Petition 870260013236, dated 11 / 02 / 2026, page 14 / 61 7 / 19 Environmental sustainability and the circular economy are becoming increasingly important to the market. DETAILED DESCRIPTION OF THE INVENTION

[0027] The features and advantages of the method according to the present invention will become more apparent from the following description. The description and the following embodiments are provided for the sole purpose of illustrating the present invention and should not be construed in a way that limits the scope of protection defined by the appended claims.

[0028] The numerical limits and ranges expressed in this description and appended claims also include the numerical value or values ​​mentioned. Furthermore, all values ​​and subranges of a numerical limit or range should be considered specifically included as if they had been explicitly mentioned.

[0029] The compositions according to the present invention may comprise, consist of, or consist essentially of the essential and optional components described in this description and the appended claims.

[0030] For the purposes of this description and the appended claims, the term essentially means that the composition or component may include additional ingredients, but only to the extent that the additional ingredients do not materially alter the essential characteristics of the composition or component.

[0031] According to the present invention, the method comprises a melting step of a first vitrifiable solid mixture to obtain molten glass to be fed into glass container forming machines.

[0032] The composition of the first solid vitrifiable mixture is of Petition 870260013236, dated 11 / 02 / 2026, p. 15 / 61 8 / 19 type known to those skilled in the art. Preferably, the first vitrifiable mixture is a mixture suitable for obtaining soda-lime glass. For example, the first vitrifiable solid mixture comprises at least quartz sand (SiO2), sodium carbonate, and calcium carbonate. The first vitrifiable solid mixture may further include one or more additive materials to give the glass the desired aesthetic and physicochemical properties. Examples of additive materials are: additional vitrification compounds (or glass formers), stabilizing agents, coloring agents, decolorizing agents, oxidizing agents, reducing agents, and refining agents.

[0033] The first vitrifiable solid mixture also preferably contains post-industrial recycled cullet (PIR cullet).

[0034] In one embodiment, the first solid vitrifiable mixture may also contain post-consumer recycled cullet (PCR cullet) in addition to the PCR cullet introduced in the form of a frit into the feed channels of the forming machines. The first solid vitrifiable mixture may also contain post-industrial recycled cullet (PIR cullet).

[0035] As used in this description, the term broken glass indicates a material formed from fragments of glass products or products containing glass.

[0036] The term “recycled glass cullet” refers to glass cullet derived from post-consumer and post-industrial waste or scrap from glass products.

[0037] The terms recycled glass shards, glass shards PCR and PCR cullet preferably comprise glass cullet derived from glass containers, for example, for packaging food, cosmetics or perfumery products, which are generally separated as municipal waste for recycling. Petition 870260013236, dated 11 / 02 / 2026, page 16 / 61 9 / 19 typically after one or more pre-treatment steps (e.g., washing, grinding, sorting based on color and size, etc.).

[0038] The terms “post-industrial recycled cullet” and “PIR cullet” preferably refer to glass waste generated during an industrial glass production cycle (e.g., products discarded due to failure to meet required quality standards, production scrap, etc.).

[0039] The first vitrifiable solid mixture can be melted in a melting furnace, for example, a tank furnace with automatic loading of the mixture components. In the melting furnace, the first molten vitrifiable mixture is generally maintained at a temperature in the range of 1,400°C to 1,500°C.

[0040] Next, the first molten vitrifiable mixture in which recycled glass frit is incorporated into the feed channels of forming machines is also called base molten glass.

[0041] The liquid glass mass produced in the melting furnace is then transferred to a refining tank, where the gases present in it are removed and any remaining undissolved residues are eliminated. From the refining tank, the first molten vitrifiable mixture is transferred to a distribution channel and from there distributed into a plurality of feed channels, each of which carries the first molten vitrifiable mixture to a respective forming machine. In the feed channels, the temperature of the first molten vitrifiable mixture is maintained, for example, in the range of 1,000°C to 1,250°C.

[0042] According to the requirements, recycled glass frit may be incorporated into the mass of the first melted vitrifiable mixture within one or more feed channels or at one or more points of the same channel. Petition 870260013236, dated 11 / 02 / 2026, p. 17 / 61 10 / 19

[0043] Frit can be prepared substantially by any of the frit-making processes known in the art. In general, frit is obtained by a process that includes the preparation and melting of a second vitrifiable solid mixture, comprising glass cullet and at least one fluxing agent, at a temperature above 1,000°C, followed by rapid cooling to obtain a new solid glass substance.

[0044] The recycled glass cullet used for the preparation of the frit preferably includes PCR cullet and / or PIR cullet, more preferably at least PCR cullet. In one embodiment, the frit does not include PIR cullet.

[0045] In one embodiment, the second vitrifiable solid mixture used to prepare the frit comprises recycled cullet in an amount ranging from 50% to 90% by weight, preferably 60% to 80% by weight, relative to the weight of the vitrifiable solid mixture, the fluxing agent and optional additive materials making up 100% by weight.

[0046] In the second vitrifiable solid mixture, cullet is therefore the main vitrification material (glass-forming material), that is, the material from which the frit mainly obtains its oxide content, in particular SiO2, Na2O and CaO.

[0047] Preferably, the glass shards usable for preparing the fritters have fragments with dimensions in the range of 5 mm to 50 mm. Preferably, the glass shards have a content equal to or less than 1% by weight of fragments with dimensions greater than 50 mm. Preferably, the glass shards have a content of fragments with dimensions less than 5 mm equal to or less than 5% by weight.

[0048] The aforementioned grain size of the glass cullet favors its fusion and, therefore, its transformation into frit.

[0049] In one embodiment, the shard of glass used is called Petition 870260013236, dated 11 / 02 / 2026, page 18 / 61 11 / 19 extra-fine quality PCR shards, i.e., a mixture of white and semi-white soda lime glass shards.

[0050] The term white glass shard indicates a colorless and transparent glass shard with an Fe2O3 content between 0.020% and 0.070% by weight.

[0051] The term half-white glass cullet indicates a relatively colorless and transparent glass with an Fe2O3 content greater than 0.070% by weight and less than 0.15% by weight.

[0052] Preferably, the cullet has a Cr2O3 content in the range of 0.0005% to 0.0020% by weight.

[0053] The second vitrifiable solid mixture for the production of recycled glass frit comprises at least one fluxing agent (also called flux). The function of the fluxing agent is to lower the melting temperature of the frit relative to the melting temperature of the cullet used to manufacture it.

[0054] The fluxing agents that can be used are the compounds commonly used for the production of glass and frits.

[0055] Examples of such compounds are: - boric anhydride (B2O3), usually in the form of anhydrous borax; - alkali metal oxides, preferably oxides of Li, Na and K (e.g., Na2O, K2O); - Alkali metal carbonate salts, preferably Li, Na and K carbonate salts (Li2CO3, Na2CO3, K2CO3).

[0056] The fluxing agent can also be a mixture of the previous compounds.

[0057] In one embodiment, the second solid vitrifiable mixture used to prepare the frit comprises at least one fluxing agent in an amount within the range of 10% to 50%, preferably 15% to 40%, more preferably 15% to 30%, Petition 870260013236, dated 11 / 02 / 2026, p. 19 / 61 12 / 19 by weight relative to the weight of the vitrifiable solid mixture.

[0058] The second solid vitrifiable mixture for frit production may also comprise one or more additional additive materials, selected, for example, from: vitrifying agents (e.g., Al₂O₃ or B₂O₃), stabilizing agents (e.g., CaO, MgO, BaO, etc.), coloring agents (e.g., iron oxides, chromium oxides, cobalt oxides, metals such as Ni, Cu, Se, Mn, Ti), decolorizing agents, oxidizing agents (e.g., NaNO₃, KNO₃), reducing agents (e.g., graphite, pyrite, carbon) and refining agents (e.g., Na₂SO₄, antimony oxide) and mixtures thereof. These additive materials may also be used to prepare the solid vitrifiable mixture used to produce the base fused glass.

[0059] Some compounds, as they are known, may have more than one function among those indicated above (for example, B2O3 may act as a vitrifying, fluxing and stabilizing agent).

[0060] Preferably, the optional additive materials are present in the vitrifiable solid mixture used to prepare the frit in an amount within the range of 0% to 15%, preferably 0.5% to 15%, more preferably 0.5% to 5%, by weight relative to the weight of the vitrifiable solid mixture.

[0061] The introduction of cullet in frit form into the base of molten glass can impart an undesirable coloration to the glass, tending towards yellow-green, due to the content of coloring agents originally present in the cullet. In such a case, if a white glass container is desired, it is preferable to incorporate at least one glass decolorizing compound into the base molten glass mass.

[0062] For this purpose, for example, bleaching compounds known to those skilled in the art may be used, Petition 870260013236, dated 11 / 02 / 2026, page 20 / 61 13 / 19 gauges are typically used in glass manufacturing processes.

[0063] Preferably, the bleaching compound is selected from: - Oxides of one or more of the following elements: Co, Ce, Er, Mn; - a metal selected from: selenium, manganese; - mixtures of the previous compounds.

[0064] Preferably, the decolorizing compound is added to the vitrifiable solid mixture to prepare the frit in a total weight amount in the range of 1 ppm to 2,000 ppm, more preferably in the range of 1 ppm to 500 ppm, relative to the weight of the vitrifiable solid mixture.

[0065] The aforementioned oxides and metals with a decolorizing function can also be used in mixtures with each other.

[0066] In one embodiment, the glass decolorizing compound can be mixed into the first molten vitrifiable mixture flowing in the feed channel in the form of a glass frit containing it, different from the recycled glass frit. Adding the decolorizing agent to the base molten glass via a frit separate from the recycled glass frit allows the decolorizing effect to be noticed more quickly, thus increasing process controllability.

[0067] Furthermore, adding the decolorizing agent to the feed channel into which the recycled glass frit is introduced allows for the production of decolorized glass with reduced consumption of decolorizing agents compared to adding it to the first solid vitrifiable mixture used to produce the base molten glass, where one or more decolorizing compounds are normally already included. Additionally, adding the decolorizing agent to the first solid vitrifiable mixture used to produce Petition 870260013236, dated 11 / 02 / 2026, page 21 / 61 14 / 19 Base molten glass can lead to non-optimal colorations of products obtained with molten glass flowing in channels where no recycled glass frit is added.

[0068] The color of the final glass container is also caused by the oxidation state of the molten vitrifiable mixture supplied to the forming machines. Advantageously, the oxidation state can be controlled by adding oxidizing agents (e.g., NaNO3, KNO3) and reducing agents (e.g., graphite, pyrite, carbon).

[0069] In one embodiment, for example, in order to reduce the green color imparted by the presence of iron oxides in cullet, it is possible to add to the second vitrifiable solid mixture used to prepare the frit at least one oxidizing agent to bring the iron to its highest oxidation state, which is associated with a yellow color instead of green. In this case, the use of NaNO3 as an oxidizing agent is particularly preferred.

[0070] In a preferred embodiment, the recycled glass frit according to the present description may have the following composition (percentages by weight with reference to the weight of the frit): - 50 to 65% SiO2 - 15 to 20% Na2O - 0 to 3% K2O - 7 to 12% CaO - 0 to 3% MgO - 0 to 3% BaO - 1 to 3% Al2O3 - 0.1 to 0.2% SO3 - 0 to 3% Li2O - 10 to 20% B2O3 - 0.03 to 0.07% Fe2O3 Petition 870260013236, dated 11 / 02 / 2026, p. 22 / 61 15 / 19

[0071] The composition of the frit is preferably selected so that its viscosity curve, that is, the trend of the viscosity value (Log η) of the frit in the liquid state as its temperature varies, is similar to that of the molten vitrifiable mixture present in the channel.

[0072] The physical-chemical and compositional characteristics of the frit can be selected by taking into account several parameters, in particular the composition of the glass cullet, the temperature and rheological characteristics of the base molten glass in which the frit is incorporated, the feed rate of the base molten glass and the length of the feed channel traversed by it (which define the time within which the melting and homogenization of the frit must be completed).

[0073] A person skilled in the art, based on their technical knowledge and / or with the aid of routine experimental trials, is able to select the quantity and type of fluxing agents and optional additive materials to obtain a recycled glass frit with adequate melting and homogenization rate in the base fused vitrifiable mixture.

[0074] Preferably, recycled glass frit has one or more of the following characteristics: - melting temperature (Tm) within the range of 1050 to 1250°C, preferably within the range of 1160 to 1200°C (according to ISO 7884-3: 1987; temperature value measured in Log η = 2, η expressed in Poise); - softening temperature (Ts) within the range of 550 to 650°C, preferably within the range of 600 to 630°C (according to ISO 7884-3: 1987; temperature value measured in Log η = 7.6, η expressed in Poise); - annealing temperature (Tm) within the range of 400 to Petition 870260013236, dated 11 / 02 / 2026, page 23 / 61 16 / 19 500°C, preferably within the range of 460 to 490°C (according to ISO 7884-3: 1987; temperature value measured in Log η = 13.3, η expressed in Poise).

[0075] Preferably, the recycled glass frit has a density in the range of 2.4 to 2.8 g / dm3, more preferably in the range of 2.5 to 2.65 g / dm3.

[0076] The fritter can be produced with equipment known to those skilled in the art.

[0077] For example, frit can be obtained by a process that includes the following steps: i. melt the second solid vitrifiable mixture comprising recycled glass cullet and at least one fluxing agent to obtain a second molten vitrifiable mixture; ii. Cool the second molten vitrifiable mixture to obtain the recycled glass frit.

[0078] The second vitrifiable solid mixture in step i above is preferably melted at a temperature within the range of 1,000°C to 1,600°C, more preferably within the range of 1,200°C to 1,500°C.

[0079] Cooling can be carried out by any suitable technique, including pouring the second melted vitrifiable mixture into water to obtain a granular-shaped frit and rolling it between cooled rolls to obtain a flake-shaped frit.

[0080] At the end of the cooling (quenching) process, the frit can be ground to obtain a powder with the desired particle size.

[0081] Preferably, the frit incorporated into the base molten glass consists of granules with an average size in the range of 1 mm to 5 mm. Preferably, the frit has a content equal to or less than 2% by weight of granules with dimensions greater than 5 mm. Preferably, the cullet has a granule content with dimensions Petition 870260013236, dated 11 / 02 / 2026, page 24 / 61 17 / 19 less than 1 mm equal to or less than 5% by weight.

[0082] Recycled glass frit can be introduced into the molten glass mass flowing in the feed channels in a variable amount within a wide range of values.

[0083] For example, recycled glass frit can be added in amounts ranging from 0.5% to 15% by weight relative to the weight of the molten glass mass flowing in the feed channel.

[0084] With the method according to the present description, it is possible to introduce a quantity of recycled glass cullet into a final glass container, for example, up to 15% by weight of the container's weight.

[0085] Glass shard frit can be combined with the melted vitrifiable mixture mass in the feed channels using conventional equipment for dosing and homogenizing it, in particular the apparatus generally used for glass staining in the channel (anti-cristle staining) by means of glass frits.

[0086] The molten vitrifiable mixture in which the frit has been included is supplied, through the feed channels, to the forming machines where the glass vessel is produced, for example, by a glass blowing process. Each feed channel is generally provided with a corresponding dosing device (feeder) to dose a desired quantity of a drop of molten glass to a respective forming machine.

[0087] The vessel may be formed, for example, by blowing, pressure blowing or any other suitable process. Once formed, the vessel is cooled to preserve the desired shape, then annealed in one or more annealing furnaces. Vessels exiting the annealing treatment may undergo any finishing treatments, for example, cutting, polishing or application of coatings (e.g., anti-reflective, etc.). Petition 870260013236, dated 11 / 02 / 2026, page 25 / 61 18 / 19 reinforcement, decorative, etc.).

[0088] Preferably, the recycled glass container obtained using the method described herein is a container in the form of a bottle, jar, jug, etc., for packaging, for example, perfumes, cosmetic products (creams, lotions, detergents, etc.), pharmaceutical products or food products. The packaged product may be in the form of a liquid, cream, paste, powder, etc.

[0089] To better understand the features of the present invention, the following embodiment is provided below. EXAMPLE 1

[0090] A recycled glass frit according to the present invention was prepared from the following vitrifiable solid mixture (percentages by weight with reference to the weight of the vitrifiable solid mixture): - 70% of PCR glass shards, - 8% lithium carbonate, - 22% anhydrous borax.

[0091] The PCR shard was of extra-silty quality (99.9% by weight of white and semi-white soda lime glass), with an Fe2O3 content of less than 0.07% and a C2O3 content of less than 0.002%, said percentages referring to the weight of the shard.

[0092] The vitrifiable solid mixture was melted in a melting furnace and the molten mass was cooled in water. The resulting frit was ground and sieved in order to select the portion of granules with dimensions in the range of 1 to 5 mm.

[0093] The following physicochemical characteristics were determined in the fritters prepared in this way: - Melting point = 1195°C - softening temperature = 620°C - Annealing temperature = 480°C Petition 870260013236, dated 11 / 02 / 2026, page 26 / 61 19 / 19 Density = 2.6 g / dm³ - Log p (O2) = - 1.95 bar.

[0094] In a melting furnace, a base molten glass was prepared from a vitrifiable solid mixture comprising virgin raw materials and internal PIR cullet, free of PCR cullet.

[0095] The frit was incorporated into a feed channel of a perfume glass bottle forming machine in an amount equal to 7% by weight relative to the weight of the base molten glass flowing in the channel.

[0096] In this way, final glass containers were obtained consisting of 5% recycled glass by weight. Petition 870260013236, dated 11 / 02 / 2026, p. 27 / 61

Claims

1. A method for producing a glass container, characterized in that it comprises the steps of: a. melting a first solid vitrifiable mixture to obtain a first molten vitrifiable mixture; b. feeding the first molten vitrifiable mixture into a plurality of glass container forming machines through their respective feed channels; c. combining at least one recycled glass frit with the first molten vitrifiable mixture in at least one of the feed channels, the frit being obtained from a second solid vitrifiable mixture comprising recycled glass cullet and at least one fluxing agent; d. forming a glass container in said forming machines using the molten vitrifiable mixture from step c.

2. Method according to claim 1, characterized in that the recycled glass frit has one or more of the following characteristics: - melting temperature in the range of 1050 to 1250°C, preferably in the range of 1160 to 1200°C; - softening temperature in the range of 550 to 650°C, preferably in the range of 600 to 630°C; - annealing temperature in the range of 400 to 500°C, preferably in the range of 460 to 490°C; - density within the range of 2.4 to 2.8 g / dm3, preferably within the range of 2.5 to 2.65 g / dm3.

3. Method, according to claim 1 or 2, characterized in that said recycled glass frit comprises Fe2O3 in an amount less than 0.1% by weight, preferably within the range of 0.03% to 0.07% by weight, relative to the weight of the frit.

4. A method according to any one of claims 1 to 3, characterized in that the recycled glass frit comprises an additive material selected from: glazing agent, stabilizing agent, coloring agent, decolorizing agent, oxidizing agent, reducing agent, refining agent and mixtures thereof.

5. Method according to claim 4, characterized in that the recycled glass frit comprises at least one glass decolorizing agent.

6. Method according to claim 5, characterized in that said at least one glass decolorizing agent is selected from: - oxides of one or more of the following elements: Co, Ce, Er, Mn, - selenium, manganese - mixtures thereof.

7. A method according to any one of claims 1 to 6, characterized in that said recycled glass frit is obtained by a process comprising the steps of: i. melting the second solid vitrifiable mixture comprising recycled glass cullet and at least one fluxing agent to obtain a second molten vitrifiable mixture; ii. cooling the second molten vitrifiable mixture to obtain the recycled glass frit.

8. Method according to claim 7, characterized in that said second solid vitrifiable mixture comprises said recycled glass cullet in an amount within the range of 50% to 90% by weight, preferably 60% to 80% by weight, relative to the weight of the solid vitrifiable mixture. Petition 870260013236, dated 11 / 02 / 2026, page 29 / 61 3 / 3 9. Method, according to claim 6 or 7, characterized in that said second solid vitrifiable mixture comprises said at least one fluxing agent in an amount within the range of 10% to 50% by weight, preferably 15% to 40% by weight, relative to the weight of the solid vitrifiable mixture.

10. A method according to any one of claims 1 to 9, characterized in that said at least one fluxing agent is selected from: - boric anhydride (B2O3), - alkali metal oxides, preferably oxides of Li, Na and K, - alkali metal carbonate salts, preferably carbonate salts of Li, Na and K, - mixtures thereof.

11. A method according to any one of claims 1 to 10, characterized in that it comprises incorporating into the first molten vitrifiable mixture from step a at least one frit, other than said recycled glass frit, comprising at least one compound selected from: coloring agent, decolorizing agent, oxidizing agent, reducing agent and mixtures thereof.

12. A method, according to any one of claims 1 to 11, characterized in that said recycled glass cullet is selected from: post-consumer glass cullet, post-industrial glass cullet and mixtures thereof.