Method for recycling paper money or special paper, fibrous suspension, recycled fibre, use of same, and paper obtained

Abstract

The present invention pertains to the fields of recovery or reuse of waste materials. The present invention discloses a method for recycling banknotes. The process of producing banknotes generates solid waste, such as paper rejected due to quality problems and printing defects, resulting in a considerable amount of waste that must be managed properly. The present invention aims to overcome the aforementioned problem and proposes a method for recycling current paper money on the basis of its composition. In this way, the recycling of scraps from the banknote manufacturing process highlights the relevance of the circular economy and the responsible use of resources in the printing industry.

Description

[0001] RECYCLING PROCESS OF PAPER MONEY OR SPECIAL PAPER, FIBROUS SUSPENSION, RECYCLED FIBER AND THEIR USE AND PAPER OBTAINED

[0002] FIELD OF APPLICATION

[0003] The present invention applies to the fields of recovery or utilization of waste materials. The present invention discloses a process for recycling waste material from the banknote production process.

[0004] BACKGROUND OF THE INVENTION

[0005] Recycling scraps from the banknote production process and / or paper money recycling represents a fundamental practice in the sustainable management of waste generated by banknote printing companies. The banknote production process typically generates solid waste from printed or unprinted paper rejects due to quality issues, paper rejected for printing adjustments, possible paper from printer jams, refills from the process of cutting sheets to the correct final banknote format, and also printed banknotes rejected due to possible printing errors or any other unacceptable defects. To handle these rejects, they are properly shredded (scraps) in special machines at printing companies to de-characterize them, thus preventing any misuse of the material after disposal or recycling.

[0006] These paper scraps can play a crucial role in reducing waste and promoting sustainability. For example, by undergoing a recycling process, they can be used as a fiber source in the manufacture of high-quality papers. This practice not only helps minimize environmental impact by reducing the amount of waste sent to landfills, but also contributes to the preservation of natural resources, as it avoids the need to produce paper from virgin raw materials. In this context, to solve the problem explained above, the present invention provides a process for recycling current paper currency based on its composition. Thus, recycling scraps from the banknote production process illustrates the importance of the circular economy and the responsible use of resources in the printing industry. STATE OF THE ART

[0007] Document PI 9605508-1 reveals the development of a technology that enables the recycling of papers containing formaldehyde-melamine-based chemical additives, a product commonly known as wet strength. Such papers, in this case currency papers, are currently incinerated or deposited in landfills and landfills, as there is no domestic technology that allows for their reuse by the recycling industry. This causes environmental and ecological problems, as this material does not decompose or dissolve in water, remaining intact in the soil, releasing printing ink and pollutants. To enable the recycling of such material, this technology was developed to enable the reuse of formaldehyde-melamine-impregnated papers. This technology involves the use of alkalis, products that act on the chemical bonds of formaldehyde-melamine.

[0008] Unlike what is reported in the above document, current paper money uses epichlorohydrin resin as its UR principle. The disuse of urea resin for this purpose is linked to its high toxicity. Although this product was historically used in papermaking to provide moisture resistance, this substance, which belongs to the formaldehyde resin family, is known for its strong and unpleasant odor, as well as its toxic nature. By changing the chemical agent, the pulp works in a neutral medium, in the pH range of 7. In the present invention, there is no need for the pulp to be immersed, and the process occurs for up to 6 hours and under controlled pressure.

[0009] Document CN109294034 discloses a method for converting waste banknotes into recycled composite material. The method comprises the following steps: Step 1. Pretreat the waste banknotes and confidential waste paper to optimize the fiber structure and morphology to obtain pre-modified fibers; Step 2. Weigh in parts by weight: 30-50 parts of pre-modified fiber, 52-67 parts of recycled polyethylene particles, 1-3 parts of maleic anhydride-grafted polyethylene, 0.5-1 part of polyethylene wax, 0.1-0.2 parts of light stabilizer, 0.1-0.2 parts of antioxidant 168; Step 3. The pre-modified fiber and recycled polyethylene granules weighed in step 2 are placed in a high-speed mixer, mixed well, and then maleic anhydride-grafted polyethylene, polyethylene wax, light stabilizer and antioxidant are added sequentially.Mix the antioxidant 168 to obtain a mixture I, and add the mixture I to the flat twin-screw extruder from the main feeding port in a uniform feeding manner, and extrude the granules for sealing; Step 4. The extruded pellet obtained in step 3 is injection molded by an injection molding machine, and then demolded and cooled to obtain a composite material.

[0010] Unlike the present invention, the above document reports the transformation of paper scraps with RU as part of a polymeric material, which will serve as raw material for the extruder.

[0011] Document BR 10 2019 003165 4 describes the production of polymer composites based on polypropylene and banknotes (banknotes of any currency) for the manufacture of objects made with polypropylene as the main material. The polypropylene used can be virgin and / or recycled. Blends of polypropylene and other polyolefins are also considered, aiming to provide a viable alternative to significantly reduce the accumulation of this waste. This technology has enabled an efficient method for recovering rejected banknotes unsuitable for circulation, based on the production of composites containing polypropylene, without the need for prior treatment of the note or impregnation with resins. The choice of polypropylene is related to its widespread industrial use, due to the diversity of items produced using this polymer.This technology leveraged the existing capacity to produce the same polypropylene items of all types, using a composite made from virgin polypropylene and / or recycled banknotes. The composite can be used to mold items used in the automotive, packaging, toy, and furniture industries, among others.

[0012] Unlike the present invention, the document above reports the reuse of paper money as an integral material of a polymeric compound aimed at the manufacture of new objects.

[0013] SUMMARY OF THE INVENTION

[0014] The banknote production process generates solid waste, such as paper rejected due to quality issues and printing errors, resulting in a considerable amount of waste that needs to be managed properly.

[0015] In this scenario, aiming to solve the aforementioned problem, the present invention offers a process for recycling current paper money, based on its composition. Thus, recycling scraps from the banknote manufacturing process highlights the importance of the circular economy, the responsible use of resources in the printing industry, the reduction of virgin fiber consumption in paper production, and the reduction of the volume of waste destined for landfills.

[0016] BRIEF DESCRIPTION OF THE FIGURES

[0017] Figure 1 illustrates the simplified flowchart of the process covering step (c);

[0018] Figure 2 illustrates the material to be recycled;

[0019] Figures 3 and 4 illustrate the final product obtained in step (c).

[0020] DETAILED DESCRIPTION OF THE INVENTION

[0021] The invention can be better understood through the following detailed description, in accordance with the attached figures.

[0022] As illustrated in part of Figure 1, the present invention reveals a process for recycling special or security paper, comprising the steps of:

[0023] (a) Perform thermal and chemical treatment of the material to be recycled by pressure cooking; and

[0024] (b) Wash the material.

[0025] Special or security paper is defined as: paper money, wine labels, abrasive paper, passports, decorative paper, stamps, official documents, among others, which contain wet-resistant resin (RU).

[0026] The material to be recycled is specialty or security paper, preferably with a 100% cotton composition and a wet strength (W / W) resin content greater than 0.25% of the final paper (1,000 kg of cotton paper / 2.50 kg of resin). This could be, for example, residual materials from banknote production or any other source, such as notes withdrawn from circulation in the market, without the need for prior cleaning. Furthermore, the size of the material to be used in the process can vary; preferably, it is suggested to use perforated material, as illustrated in Figure 2, since the larger the contact area, the greater the favoring of the chemical reactions present here. However, size is not an impediment.

[0027] The process is batch-based, so in step (a), the material is weighed, for example, 1000 kg or 2000 kg, depending on the equipment used. The material undergoes thermal and chemical treatments to break it down into reusable fibers, break down the original wet strength of the special or security paper, dissolve the polyester-based security threads, and disperse the various inks, metallic pigments, resins, and varnishes used in the banknote printing process.

[0028] Thermal and chemical treatment is performed in equipment that agitates the cooking process, such as spherical or cylindrical rotary digesters or autoclaves. These devices are preferably made of carbon steel and coated externally with insulating material for improved heat exchange and thermodynamic losses.

[0029] As an example, the capacity for a spherical digester with a volume of 10.8 m 3 is 1000 kg of material per batch and in the cylindrical digester with a volume of 23 m 3 is 2000 kg per batch.

[0030] The material to be recycled is dosed with water and an alkaline agent, preferably caustic soda. The alkaline agent concentration used is 48.5% to 50.5% by weight, preferably 50%. The proportions used in the process include a charge of 2 parts water and 0.1 part alkaline agent to 1 part material to be recycled (volume / weight). For example, for every 2,000 L of water, 1,000 kg of material to be recycled and 100 L of alkaline agent are used. The quality of the water used is invariable; for example, industrial water with a color standard >30 uc and turbidity >2.0 ntu can be used. After feeding the material to be recycled, water, and the alkaline agent solution into the equipment, it is hermetically sealed to begin the pressure cooking process.

[0031] The internal pressure of the equipment is increased from 4.3 to 4.7 bar and controlled by introducing saturated steam from, for example, a boiler in the company's utilities area.

[0032] A movement, preferably rotational, is applied with the aim of homogenizing the material during the process, making the chemicals interact uniformly with the chips being treated.

[0033] Once the material has been cooked, which can last up to 7 hours, the equipment's pressure is gradually released, for example, over 3 hours, to atmospheric pressure (1 atm = 101325 Pa) through relief valves. Once the cooking equipment is depressurized, it is opened through the airtight lid, and the treated material is transferred to a tank, where it will be fed to the next stage: washing.

[0034] In step (b), the material is washed to reduce the pH of the medium, preferably under moderate agitation. The washing process involves adding water with a pH close to 7 to the tank and soaking the freshly cooked material from step (a) in the equipment for an average of 3 hours. Optionally, 11-12% aluminum sulfate at pH 3.0 can be added to a 1% solution, in a ratio of 0.02 parts aluminum sulfate to 1 part recycled material (volume / mass), to speed up the washing process by reducing the pH. Subsequently, the water is removed, and fresh water is added to the washing tank. Throughout the washing process, the suspension's pH is monitored; when values ​​between 7.0 and 8.0 are reached, the process is complete, resulting in a fibrous suspension with a neutral pH that can be used in the production of any product using this raw material, including paper and any other fibrous product.

[0035] The fibrous suspension obtained from the process comprises a neutral pH between 7.0 and 8.0 and 50% in water.

[0036] To produce specialty paper, an additional step can be added to the process: water extraction (step (c). This extraction facilitates the use of the fibrous suspension in the papermaking process.

[0037] In step (c) the extraction of water from the material after washing is carried out by removing the water from the fibrous suspension by means of gravity drainage on a forming screen, for example made of polyester, and subsequently the material is pressed, for example, with pneumatic pressure of between 3 - 4 bar, and preferably with a wet press up to a value of up to 50% moisture in the recycled material.

[0038] Optionally, the wet press can be lined with felt.

[0039] This process does not entirely remove the color from the base material used, and the resulting fibers still contain a certain amount of particles from pigments, security threads, etc. The total process loss is estimated at approximately 10% of the original amount of banknote trimmings initially acquired.

[0040] At the end of step (c), a recycled fiber is obtained that can be used in the production of paper and any other product of fibrous origin, as illustrated in figures 3 and 4.

[0041] The fiber obtained from the process with the addition of step (c) has a pH between 7.0 and 8.0, an average moisture content of 10% to 50% and a light and opaque color.

[0042] In this way, obtaining special paper from the process of the present invention can be carried out directly from step (b) with the fibrous suspension or from the fiber obtained after step (c).

[0043] The fibrous suspension, as well as the fiber obtained from the process, can be used to manufacture paper or any other product of fibrous origin, such as packaging, hygienic mats, acoustic insulation, among others.

[0044] In this way, any paper product or any other product of fibrous origin can be produced, such as special paper, banknotes, passports and tax stamps, comprising among one of its constituents the fibrous suspension or fiber as obtained by the process of the present invention.

[0045] As can be seen, this invention enables a circular economy for a product—waste banknotes—that until now has not been able to be used for the production of the base product: paper. This reduces reliance on virgin raw materials and provides a valuable renewable input option for the paper market: cotton fiber.

[0046] The invention will be elucidated by the following examples, without being limited to or by them.

[0047] Examples

[0048] Example 1: Obtaining recycled specialty paper with fiber obtained from additional step (c). To obtain recycled specialty paper, the fiber obtained in step (c) undergoes a disaggregation of the fibrous raw materials. That is, the material passes through a tank equipped with rotating blades that disaggregate the fed material. The work is done at a consistency (mass / mass concentration) of approximately 5%, that is, 5% consistency means that there is a ratio of 5 g of fibrous material (solid) to 100 g of water (liquid).

[0049] This disaggregated mass then passes through rotating blades that modify the fibers appropriately for paper production, with optional controls: inlet and outlet pressure at 2.5 to 4.0 Pa, electrical current of the equipment, which must be constant, and Schopper degree (°SR - unit of measurement referring to the degree of drainage of a fibrous suspension) according to the desired specification for the final paper.

[0050] This refined pulp is fed to a tank where it receives additives such as dyes and bleaches, and continuously dosed additives such as glue, starch, retainers, coagulants, mineral fillers, and others, depending on the desired customization of the final product. The refined pulp is then screened to remove some of the impurities in various centrifugal purifiers and fed through a distributor to the paper machine's inlet box, then to the tank that feeds the paper machine.

[0051] The headbox distributes this fibrous suspension through a metering lip onto the flat table (Fourdrinier), whose function is to form the paper by dewatering it onto a perforated plastic screen. At the end of this stage, the continuous sheet of paper has a dry content of approximately 20%.

[0052] After this sheet passes through presses equipped with felts to absorb the water removed by this pressure until a dry content of approximately 40%.

[0053] The sheet is then dried using steam-heated cylinders until the product reaches its final moisture content of approximately 5%.

[0054] In the middle of the drying process, the continuous sheet can receive a surface bath treatment (normally a modified starch) to improve some of the paper's properties in a dosing equipment called a size press or size press.

[0055] After this treatment, the paper is dried again using steam-heated cylinders or infrared dryers.

[0056] Some papers also receive mechanical treatment using heated steel or rubber-coated calenders to improve the uniformity of the paper surface (smoothness, roughness), as well as to partially adjust the thickness of the product.

[0057] The paper is then rolled onto spools and removed from the paper machine.

[0058] These rolls, called jumbo rolls, are destined for a finishing equipment called a rewinder where these rolls are wound under tension and cut to the required width into reels.

[0059] These coils can then be packaged for their destination and sale or go through cutters where they are cut into sheets and then packaged for sale.

[0060] The present invention has been disclosed in this descriptive report in terms of its preferred embodiment. However, other modifications and variations are possible from the present description, still being within the scope of the invention disclosed herein.

Claims

MODIFIED CLAIMS Received by the International Secretariat on 19 December 2024 (19.12.2024) 1. Special or security paper recycling process, CHARACTERIZED by comprising the steps of: (a) carry out thermal and chemical treatment of the material to be recycled by pressure cooking; in which the material to be recycled is subjected to thermal and chemical treatment in equipment that performs agitation at the time of cooking, in which the material to be recycled is dosed with water and an alkaline agent, in which the concentration used of the alkaline agent is 48.5% to 50.5% by weight; the proportions comprising a load of 2 parts of water and 0.1 part of alkaline agent for 1 part of material to be recycled (volume / weight); where, after feeding the equipment with the material to be recycled, water and alkaline agent solution, it is hermetically sealed to begin the pressure cooking process, where the internal pressure is raised from 4.3 to 4.7 bar and controlled with the introduction of saturated steam;Once the material has been cooked, the pressure in the equipment is gradually released to atmospheric pressure to open the hermetic lid and the treated material is transferred to a tank. and; (b) washing the material, in which said washing is carried out under agitation; where the washing takes place by inserting water with a pH close to 7 into the tank and leaving the recently cooked material from step (a) to soak for 3 hours; subsequently, the water is removed and new water is inserted into the washing tank; throughout the washing, the pH of the suspension is controlled; when values ​​between 7.0 and 8.0 are reached, the process is finished, obtaining a fibrous suspension.

2. Process, according to claim 1, CHARACTERIZED in that the material to be recycled is special or security paper, preferably with a composition of 100% by weight of cotton and a resin participation with wet strength (RU) greater than a participation of 0.25% on the paper. MODIFIED SHEET (ARTICLE 19) 3. Process, according to claim 1 or 2, CHARACTERIZED by the size of the material to be used in the process being variable, preferably, the material being perforated.

4. Process, according to claim 3, CHARACTERIZED by the fact that the equipment that performs agitation at the time of cooking are rotary digesters or autoclaves of spherical or cylindrical shape and are constructed of carbon steel coated externally with insulating material.

5. Process, according to claim 4, CHARACTERIZED by further comprising the addition of aluminum sulfate 1 1 - 12% m / m and pH 3.0 to a 1% solution, in a proportion of 0.02 parts of aluminum sulfate to 1 part of recycled material (volume / mass).

6. Process, according to claim 5, CHARACTERIZED by further comprising a step (c) to produce special paper, which is the extraction of water, carried out by means of the removal of water from the fibrous suspension by means of gravity dewatering in a forming screen and, subsequently, the material is pressed, preferably, with a wet press to a value of up to 10% humidity.

7. Process, according to claim 6, CHARACTERIZED in that the wet press is additionally coated with felt.

8. Fibrous suspension CHARACTERIZED by being obtained by the process, as defined in claim 1, comprising neutral pH between 7.0 to 8.0 and 50% in water.

9. Recycled fiber CHARACTERIZED by being obtained from the extraction of water from the fibrous suspension, as defined in claim 8, comprising a pH between 7.0 to 8.0, average moisture content of 10% to 50% and a light and opaque color.

10. Use of fibrous suspension, as defined in claim 8, CHARACTERIZED by being for the production of paper or a product of fibrous origin. MODIFIED SHEET (ARTICLE 19) 11. Use of recycled fiber, as defined in claim 9, CHARACTERIZED by being for the production of paper or a product of fibrous origin.

12. Paper or product of fibrous origin CHARACTERIZED by comprising fibrous suspension, as defined in claim 8.

13. Paper or product of fibrous origin CHARACTERIZED by comprising recycled fiber, as defined in claim 9. MODIFIED SHEET (ARTICLE 19)

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