Process for the extraction of cellulose fibers from pineapple plant waste

Abstract

An environmentally-friendly and economic process for the manufacture (extraction) of cellulosic fibers from natural raw materials, preferably inedible waste (e.g. leaves) of the pineapple plant is disclosed. The obtained cellulosic fibers are characterized by high purity, high whiteness, and high strength, and can be used in the paper-industry in pure form, or in admixture with cellulosic fibers from other sources for the production of paper, cardboard, or other articles comprising cellulose.

Description

eco:fibr GmbH November 15, 2024119166P1452PC2 Process for the Extraction of Cellulose Fibers from Pineapple Plant Waste FIELD OF THE INVENTION

[0001] The invention relates to a method of processing inedible parts of plants,in particular the pineapple plant, e.g. crowns and leaves, for the manufacture(extraction) of high purity and high whiteness cellulose fibers, which can be usedin the paper industry as raw material for the production of paper, cardboard, andother articles comprising cellulose. BACKGROUND OF THE INVENTION

[0002] Even in the digital era, demand for products made from paper orcardboard remains huge: Books, newspapers, boxes, cups, receipts, posters,tickets, shopping bags etc. are all made from paper or cardboard. Cellullosicfibers, needed for the production of such products, are generally extracted from wood. Although growing environmental concerns give rise to an increased awareness and the striving for more sustainability such as the incorporation ofrecycled paper into newly produced paper, around 4 million hectares of forest(the size of the Netherlands) are chopped every year due to the demand of thepaper industry.

[0003] On the other hand, mankind consumes large amounts of tropical fruits,discarding inedible parts of the plants. The plant species Ananas comosus, commonly referred to as pineapple, is a herbaceous perennial originally indigenous to South America. Pineapple is a popular tropical fruit that generateshuge quantities of processing and on-farm waste. In Costa Rica alone, one ofthe world's largest pineapple exporters, 4.5 million tons of pineapple plant wasteaccrues every year. This agricultural waste is either left to rot, mechanicallyeco:fibr GmbH November 15, 2024119166P1452PC2 crushed, or burned, with the remainder then ploughed under. This disposalroute not only leads to undesired creeping acidification and pollution of arable land, it also causes costs of about 1000 to 2500 US Dollars per hectare ofcultivated pineapple.

[0004] The non-fruit wastes generated from pineapple production are theleaves, stems, and crowns. These parts of the plant mainly consist of water,with moisture contents of about 80 wt.%. The dry mass of crown leaves containsbetween 30 and 45 wt.% cellulose, between 20 and 25 wt.% hemicellulose,around 10 wt.% lignin, and about 2 wt.% pectin. It is obvious that tapping thislarge reservoir of valuable cellulosic fibers in plant waste is highly desirable fromenvironmental and economical viewpoints. It would benefit the agricultural sector in the pineapple-producing countries, reduce CO2 emissions by nothaving to burn the waste, and it would help to reduce worldwide deforestation.

[0005] Any process that aims to generate cellulosic fibers that are suitable forindustrial applications, requires the removal of non-cellulosic componentspresent in the plants. Substances like lignin, pectin, proteins, waxes, amino acids, salts, and other small matter are all undesired impurities in the paperindustry and must be eliminated. The degree to which their removal is achievedcan serve as a quality indicator of the cellulose extraction process.

[0006] Processes for the extraction of cellulose from parts of the pineapple planthave long been known in the art. GB2085500A, for example, disclosed amethod consisting of the three steps "degumming", "delignification", and "softening" of raw fibers extracted from pineapple leaves by decortication.

[0007] Yet there is no industrial process for the extraction of cellulose frompineapple currently established. Fibers obtained in the prior art often containedrelatively large amounts of residual lignin, rendering the fibers stiff and slightly colored. Other problems were low yields and the high energy demand necessary for heating and applying high pressure, posing a financial hurdle. Large amounts of environmentally hazardous waste waters containing sulfur and / or chlorine compounds were often generated, complicating the industrial applicability of the processes. Problems like these have to be overcome if theeco:fibr GmbH November 15, 2024119166P1452PC2 large amount of cellulose currently hidden in natural raw material waste, like inpineapple waste is to be harnessed for useful applications.OBJECT OF THE INVENTION

[0008] There is a need for an extraction method of cellulose fibers from inedibleparts of plants, in particular of the pineapple plant, that not only isenvironmentally friendly and economically viable, but also produces cellulose fibers useful as raw material in the paper industry, which requires the fibers to be of high purity, high whiteness and high strength.SUMMARY OF THE INVENTION

[0009] The present invention discloses an environmentally friendly andeconomically viable process by which cellulose fibers can be extracted fromnatural raw material, preferably pineapple plant waste.

[0010] In particular, the invention relates to a process for the manufacturing ofcellulosic material from natural raw material, comprising the step of basic digestion of the natural raw material, comprising bringing into contact the natural raw material with an alkaline aqueous solution; wherein no pre-treatment using acid and / or homogenization is conducted.

[0011] Further according to the invention is that the process can comprise oneor more of the following steps: a) provision of the natural raw material; and / or b)shredding the natural raw material; and / or, c) partially drying the natural rawmaterial; and / or d) filtration; and / or e) neutralization; and / or f) washing; and / or g) bleaching; and / or h) pressing; and / or i) washing with at least one alcohol; and / or j) drying; and / or k) recovery of chemicals used in the claimed process, e.g. recovery of the at least one alcohol; l) separation of the enzyme bromelain and / or lignin; m) use of waste water obtained from other steps a) to l), inparticular from steps c), e) and / or f) for the production of biogas.

[0012] Further according to the invention is that the natural raw material used inthe process can comprise not more than 25 wt.% of lignin and / or wherein theeco:fibr GmbH November 15, 2024119166P1452PC2 natural raw material can comprise at least 30% by weight of cellulosic material, based on the total dry mass of the natural raw material.

[0013] Further according to the invention is that the natural raw material used inthe process can comprise plant waste stemming from the species Ananas comosus, preferably comprising the leaves and / or fruit crowns of said plant, flax (Linum usitatissimum), bamboo (Bambusoideae), sugar cane (Saccharum officinarum), Corchorus, kenaf (Hibiscus cannabinus), cannabis, sisal (Agave sisalana), lygeum (Lygeum spartum), ramie (Boehmeria nivea), coconut (Cocos nucifera), Rosa canina, agave (Agave tequilana), or mixtures thereof.

[0014] Further according to the invention is, that the basic digestion in theprocess can be performed in an alkaline aqueous solution with a pH valuebetween 9 and 14, preferably between 10 and 14, and / or at a temperaturebetween 50 and 120 °C, preferably between 60 and 100 °C, more preferably between 70 and 90°C.

[0015] Further according to the invention is that it is possible that in the processno chemical compounds comprising chlorine or sulfur atoms are used.

[0016] Further according to the invention is that in the process the insolublesolids obtained after basic digestion can be washed with at least one alcohol,wherein the at least one alcohol is selected from ethanol, n-propanol, butanol, pentanol, hexanol, cyclohexanol, or a mixture thereof, with the preferred alcohol being ethanol.

[0017] Further according to the invention is that the alkaline aqueous solutionfor the basic digestion in the process can be reused multiple times, until the pHof said solution has dropped to a value which renders the solution ineffective in further alkaline digestion steps, preferably until the pH value has dropped below 9.

[0018] Further according to the invention is that the fibrous material obtainedafter basic digestion in the process and, optionally, washed with at least onealcohol, can be bleached, preferably by treatment of the fibrous material with analkaline aqueous hydrogen peroxide solution.eco:fibr GmbH November 15, 2024119166P1452PC2

[0019] Further according to the invention is a cellulosic material or a cellulosicmaterial obtained by the process according to the invention, wherein the cellulosic material can be characterized by a cellulose content of more than 80wt.%, preferably more than 85 wt.%, based on the total weight of the cellulosic material, and / or a fiber length of individual cellulose fibers between 0.5 and 4 mm, and / or a fiber diameter of individual cellulose fibers between 15 and 25 µm.

[0020] Further according to the invention is that the cellulosic material can becharacterized by a tensile energy absorption (TEA) of at least 25 J / m2, and / or a tensile index of at least 35 Nm / g, and / or a maximum strain of not more than 2.5 %, measured according to DIN EN ISO 1924-2 and / or after grinding of the cellulosic material in a Jokro-grinder according to DIN 54360 for 5 minutes the cellulosic material is characterized by a tensile energy absorption (TEA) of at least 70 J / m2, and / or a tensile index of at least 55 Nm / g, and / or a maximum strain of not more than 2.5 %, measured according to DIN EN ISO 1924-2.

[0021] Further according to the invention is the use of the cellulosic materialaccording to the invention, or as manufactured according to the process according to the invention as substitute for cellulosic material stemming from wood.

[0022] Further according to the invention is the use of the cellulosic materialaccording to the invention, or as manufactured according to the process according to the invention for manufacturing of an article.

[0023] Further according to the invention is an article comprising the cellulosicmaterial according to the invention, or as manufactured according to the process according to the invention, wherein the article can be for example paper, cardboard, tissue, textile, composites, molded pulp, insulation material, nanocellulose or fleece.

[0024] Further according to the invention is the manufacturing of an articleaccording to the invention comprising using a cellulosic material according to the invention, or as manufactured according to the process according to the invention.eco:fibr GmbH November 15, 2024119166P1452PC2 DETAILED DESCRIPTION OF THE INVENTION

[0025] The object is achieved by a process for the manufacturing of cellulosicmaterial form natural raw material, comprising the step of basic digestion of thenatural raw material, comprising bringing into contact the natural raw material with an alkaline aqueous solution; wherein no pre-treatment using acid and / orhomogenization is conducted.

[0026] The process according to the invention can comprise optionally one ormore of the following steps: a) provision of the natural raw material; and / or b)shredding the natural raw material; and / or, c) partially drying the natural rawmaterial; and / or d) filtration; and / or e) neutralization; and / or f) washing; and / or g) bleaching; and / or h) pressing; and / or i) washing with at least one alcohol; and / or j) drying; and / or k) recovery of chemicals used in the claimed process, e.g. recovery of the at least one alcohol; l) extraction of the enzyme bromelain.

[0027] The natural raw material used in the process according to the inventioncan comprise or consist of parts, in particular of waste parts of the pineappleplant (also referred to herein as Ananas comosus). Leaves, stems and crownsof pineapples accumulate in large quantities in countries that cultivate thetropical fruit, and are usually burned or otherwise disposed of, without any specific use. Pineapple plant waste can be used because of its readily and cost-efficient availability, however, any plant waste that has a sufficiently low lignin content, preferably lower than 25 wt.%, based on the dry mass of the naturalraw material, and / or a sufficiently high cellulose content, preferably higher than30 wt.%, based on the dry mass of the natural raw material, can also be used.Further example plants are flax (Linum usitatissimum), bamboo (Bambusoideae), sugar cane (Saccharum officinarum), Corchorus, kenaf (Hibiscus cannabinus), Cannabis, sisal (Agave sisalana), lygeum (Lygeumspartum), ramie (Boehmeria nivea), coconut (Cocos nucifera), Rosa canina,eco:fibr GmbH November 15, 2024119166P1452PC2 agave (Agave tequilana). It is also possible to combine plant waste fromdifferent sources and different plants.

[0028] Dry masses of natural raw material can be determined by heating to105°C until the weight is constant. Lignin contents of natural raw material can be determined, for example, according to the method of Savard: Hydrolysis ofhemicellulose and cellulose through treatment of the natural raw material with sulfuric acid; lignin is obtained as insoluble residue, which allows to calculate its content. Cellulose contents can be determined according to the KürschnerHoffner method, which oxidizes and removes lignin and hemicellulose by nitric acid in alcohol.

[0029] Once the natural raw material as described above is provided (step a)),it can be subjected to the process according to the invention, i.e. the basicdigestion step, comprising bringing into contact the natural raw material with an alkaline solution. No pre-treatment using acid and / or homogenization and / orheat-treatment is conducted prior to the basic digestion. Preferably, the naturalraw material is only subjected to a shredding step prior to the basic digestion. The basic digestion mainly aims at the removal of lignin and / or hemicellulose at least partially, preferably completely. Lignin is a complex phenolic polymer that provides an embedding structure for the cellulosic polymers of the secondary cell walls of plants. It is insoluble in water but can be dissolved under certain conditions in various solvents. The process according to the invention preferablyemploys a mild alkaline approach: atmospheric pressure and / or pH valuesbetween 9 and 14 and / or temperatures between 50 to 120°C. In particular, pHvalues range between 9 and 14, or between 10 and 14, or between 11 and 14, or between 10 and 13, or between 11 and 13. Preferred are pH values between 10 to 14. In particular temperatures from 50°C to 120°C are employed, or from60°C to 120°C, or from 70°C to 120°C, or from 80°C to 120°C, or from 90°C to 120°C, or from 50°C to 110°C, or from 60°C to 110°C, or from 70°C to 110°C, or from 80°C to 110°C, or from 90°C to 110°C, or from 50°C to 100°C, or from 60°C to 100°C, or from 70°C to 100°C, or from 80°C to 100°C, or from 80°C to 100°C, or from 50°C to 90°C, or from 60°C to 90°C, or from 70°C to 90°C.eco:fibr GmbH November 15, 2024119166P1452PC2 Preferably, temperatures from 60°C to 100°C, or from 70 °C to 90 °C areemployed.

[0030] The alkaline aqueous solution used for the basic digestion is prepared bydissolving alkali and / or earth alkali metal hydroxides, preferably sodium hydroxide, in water. Concentrations of the hydroxide salts in the alkaline aqueous solution with which the natural raw material is to be treated, range from1 wt% to 10wt%, or from 1.5 wt% to 10wt%, or from 2 wt.% to 10 wt.%, or from1.5 wt% to 8 wt%, or from 2wt% to 8 wt%, or from 1.5wt% to 6wt%, or from 2 wt% to 6 wt%, or from 1.5 wt% to 3.5 wt%, or from 1wt% to 3.5 wt%, preferablyfrom 1 wt.% to 4 wt.%; wherein the wt% are based on the total weight of thealkaline aqueous solution.

[0031] Immersion of natural raw material in the alkaline aqueous solution canlast from 0.5 to 8 hours, or from 1 to 8 hours, or from 1.5 to 8 hours, or from 0.5to 7 hours, or from 1 to 7 hours, or from 1.5 to 7 hours, or from 0.5 to 6 hours,or from 1 to 6 hours, or from 1.5 to 6 hours, or from 0.5 to 4 hours, or from 1 to4 hours, or from 0.5 to 3 hours, or from 1 to 3 hours, or from 0.5 to 2 hours, orfrom 1 to 2 hours, preferably from 0.5 to 2 hours.

[0032] The weight ratio of natural raw material (dry weight) : alkaline aqueoussolution is preferably as concentrated as possible, i.e. below 1:20. Particularly, the weight ratio of natural raw material (dry weight): alkaline aqueous solution is at most 1:15, or at most 1:12, or at most 1:10, or at most 1:8, or at most 1:5, or at most 1:3, or between 1:15 to 1:3, or between 1:15 to 1:5, or between 1:10 to 1:3, or between 1:10 to 1:5, or between 1:3 to 1:8, or between 1:3 to 1:5, preferably between 1:3 to 1:8.

[0033] Preferably, the weight ratio of natural raw material (dry weight) : NaOH(dry weight) is in the range of 1 : 0.6 to 1: 0.03, or 1:0.6 to 1:0.15, or 1: 0.4 to 1:0.1.

[0034] During the basic digestion step, the mixture can be stirred or moved toincrease the efficiency of the reaction.

[0035] The resulting mixture of the basic digestion step contains insolubleresidues comprising or consisting of cellulosic material and a liquid phase whicheco:fibr GmbH November 15, 2024119166P1452PC2 contains the alkaline aqueous solution and further components, like water stemming from the natural raw material, and / or side-products also stemming from the natural raw material.

[0036] The conventional way of removing lignin and / or hemicellulose from e.g.wood to obtain the cellulosic material, the so-called Kraft process, uses sulfideand sulfate under harsh conditions, with temperatures up to 180°C and pressures up to 10 bar, to transform wood into pulp. The dry mass of wood is typically composed of about 25-30 wt.% lignin, and 70 wt.% cellulosic carbohydrates, with roughly 45 wt.% cellulose and 25 wt.% hemicelluloses. Incontrast thereto, the lignin-content of the natural raw material used in the process according to the invention is at most 25 wt.%. For example, dried pineapple leaves contain only around 10 wt.% lignin, much less than wood. Itwas found that the harsh conditions of the Kraft process to remove lignin to a degree that satisfies the requirements of the paper-industry are therefore not needed in the process according to the invention. The low toxicity of the chemicals used in the present invention, as well as the milder conditions (temperature and pressure) compared to those used in the traditional Kraft process, simplifies the process, thus contributing to reduced running costs. In addition, the risk of environmental and health damages is reduced.

[0037] The process according to the invention can be performed under relativelymild conditions, with the highest temperature of 120 °C being applied during the basic digestion described above. It is furthermore possible to altogether avoid chemical compounds that contain sulfur or chlorine atoms, such as sulfate, sulfite, chlorate, chlorite, or hypochlorite, with all the positive consequences for the environment and human health.

[0038] Another advantage of the mild conditions is that the alkaline aqueoussolution can be reused several times. Every process cycle results in a certain dilution of the alkaline aqueous solution by virtue of the residual water in the natural raw material. The alkaline aqueous solution can be reused until its pH has reached values too low to be effective. Alkaline aqueous solutions with pH values below 9 are considered to be ineffective.eco:fibr GmbH November 15, 2024119166P1452PC2

[0039] In the process according to the invention, the natural raw material can beshredded (optional step b)) prior to the basic digestion step, e.g. in a chopperuntil a particle size of approximately 5 mm diameter is reached. The shredding damages the plant cell walls, which makes the cellulose fibers more accessible, and also aids in (optional) following steps, namely the removal of water from theshredded natural raw material. Optional step b) thus results in a sludge ofnatural raw material.

[0040] Further it is possible to subject the natural raw material, which can e.g.be derived from above described step b) to a drying step (optional step c)), inwhich the natural raw material is at least partially dried, i.e. dewatered bysuitable means, preferably by mechanical means, in particular by pressing.Drying can be conducted until a moisture content of about 20 to 60 wt.% isachieved. The juice separated and obtained in step c) usually comprises plantextractives such as polyphenols or pectins, among which some may prove valuable and worth isolating. In case pineapple material is used as natural raw material, the juice gathered during this drying step comprises polyphenols,pectins, and / or proteins, like the enzyme bromelain that can be isolated byextraction in a separate process (optional step l)). Bromelain finds wide-spreaduse in the food and pharmaceutical industry for the production of various value- added end products. Further, it is possible to use the waste water obtained fromother steps of the process according to the invention, e.g. the waste water of step c) for the production of biogas. The waste water obtained in the steps of the process according to the invention may have a netto energy potential of 0.02 and even up tp 0.1 MWh per ton of dried natural raw material (optional step m)).

[0041] Above described steps a) to c) can be conducted prior to the basicdigestion step.

[0042] Further, it is also possible to conduct one or more additional processsteps after the basic digestion step is complete:

[0043] It is possible to subject the mixture obtained in the basic digestion stepto one or more phase separation steps, where the liquid phase gets separated from the insoluble residue (step d)). Phase separation can be effected by simpleeco:fibr GmbH November 15, 2024119166P1452PC2 decantation, but is preferentially achieved through filtration, for example by using a drum or a belt filter The insoluble residue comprising or consisting ofcellulosic material usually remains as a sludge after step d), i.e., a mixture ofinsoluble solids and residuals of the liquid component, which could not beremoved by the phase separation process.

[0044] The sludge obtained in step d) can then subjected to one or moreneutralization steps (step e)). The neutralization can be achieved with a diluteacid such as acetic, citric, nitric, hydrochloric, phosphoric, or sulfuric acid. The preferred acid is acetic acid. Because the volume of the liquid component in thesludge increases through the neutralization step, the now neutral liquid component in the sludge is removed from insoluble solids, comprising or consisting of cellulosic material by another filtration step (step d)).

[0045] The insoluble residue contained in the sludge comprises or consists ofthe desired cellulosic material.

[0046] The lignin, removed from the cellulosic fibers and partially decomposedby the basic digestion described above, can potentially be isolated from the alkaline aqueous solution in a separate process step (step l)). The chemicalindustry provides many profitable uses of lignin. Some examples comprisechemical products like adhesives, polymers, polyols, sizing, coating and emulsifier agents. In the majority of the prior art, sulfuric acid is employed fordelignification, which is why the wastewater contains not only (partiallydecomposed) lignin, but also sulfate. It is therefore difficult to isolate sulfate-free lignin, which is a sought-after product by the chemical industry. The isolation of sulfate-free lignin is made possible by the process according to the invention.

[0047] After the basic digestion, the insoluble solids can still contain smallamounts of organic matter such as waxes, amino acids and oligopeptides. Thisorganic matter can, optionally, be removed by washing the insoluble solids in aliquid comprising or consisting of at least one alcohol (step i)). The liquidcomprising or consisting of at least one alcohol dissolves the small organicmatter. This step is usually performed at temperatures between 10 and 30°C and can last for 1-8 hours. Preferred conditions are room temperature and 1-2eco:fibr GmbH November 15, 2024119166P1452PC2 hours. Alcohols suitable for this extraction are small, linear or branched, acyclicor cyclic aliphatic alcohols, such as ethanol, n-propanol, butanol, pentanol, hexanol, cyclohexanol, or mixtures of thereof. The preferred alcohol is ethanol.

[0048] The resulting suspension can then be filtered (step d)), and the insolubleresidue, comprising or consisting of cellulosic material, washed with water (stepf)). The filtrate, which is a liquid comprising or consisting of the alcohol or alcohols used for the extraction as well as the small organic matter removedfrom the insoluble solids, comprising or consisting of cellulosic material, obtained after the basic digestion, can be subjected to a separate distillationprocess, which allows to regain the alcohol or the alcohols used for theextraction (step k)). The thereby obtained alcohol or alcohols can then bereused in step i) of a new process cycle. By implementing this measure, theamount of organic waste fluid, as well as the overall process costs, is optimized.The insoluble residue obtained after step i), optionally followed by step f) and / orstep f) comprises or consists of fibrous cellulosic material, which can still becontaminated by small amounts of lignin and / or hemicellulose and / or protein that could hitherto not be removed.

[0049] In order to increase further the purity of the fibrous cellulosic material, anoptional bleaching step (step g)) can be applied. Small amounts of lignin, which resisted the basic digestion, can be eliminated by bleaching, leading to improved whiteness levels of the final product. Bleaching of the fibrous material can be achieved by various oxidative chemical agents, particularly chlorate, chlorite and hypochlorite or hydrogen peroxide. In particular, in the processaccording to the invention, hydrogen peroxide in a slightly basic aqueous media is employed as bleaching agent in step g). The concentration of bleachingagent, preferably hydrogen peroxide in the aqueous bleaching media should be between 2 and 10 wt%, or between 3 and 10wt%, or between 4 and 10 wt%, orbetween 2 and 9 wt%, or between 3 and 9 wt%, or between 4 and 9 wt%, or between 2 and 8wt%, or between 3 and 8 wt%, or between 4 and 8 wt%, , orbetween 2 and 7 wt%, or between 3 and 7 wt%, or between 4 and 7 wt%, or between 2 and 6 wt%, or between 3 and 6 wt%, or between 4 and 6 wt%,eco:fibr GmbH November 15, 2024119166P1452PC2 preferably between 2 and 9 wt%, or between 3 and 8 wt%, or between 3 and 6wt% based on the total weight of the aqueous bleaching media.

[0050] The alkaline conditions of the bleaching media can be generated bydissolution of alkali or earth alkali hydroxides in water. pH values of the bleaching media should be between 8 and 12, or between 9 and 12, or between10 and 12, or between 8 and 11, or between 9 and 11, preferably between 9and 11. Typical alkali or earth alkali hydroxides, such as sodium, potassium ormagnesium hydroxide, or mixtures thereof, can be used. The preferredhydroxide salt for use in the bleaching media is sodium hydroxide.

[0051] Ideally, the bleaching composition also comprises at least one anti-foaming agent, in order to prevent foaming due to the development of molecular oxygen during the process. Anti-foaming agents suitable for bleaching areknown in the art. Typical concentrations range from 0.001 wt.% to 0.01 wt.%.

[0052] Bleaching times typically range from 30 min to 4 hours, or from 1 hour to4 hours, or from 2.5 hours to 4 hours, or from 3 hours to 4 hours, or from 30 minutes to 3 hours, or from 1 hour to 3 hours, or from 1.5 hour to 3 hours, or from 2 hours to 3 hours, or from 30 minutes to 2 hours, or from 1 hour to 2 hours, preferably 30 min to 120 min. Bleaching temperatures can range from 30°C to90°C, or from 40°C to 90°C, or from 50°C to 90°C, or from 60°C to 90°C, or from30°C to 80°C, or from 40°C to 80°C, or from 50°C to 80°C, or from 60°C to 80°C, or from 30°C to 70°C, or from 40°C to 70°C, or from 50°C to 70°C, preferably50°C to 70°C.

[0053] Preferably, the bleaching is conducted in one bleaching step. This meansthat the bleaching is conducted only once, in particular within the above defined time frames and / or temperature ranges. This has the advantage of saving water, reagents and energy.

[0054] The combination of the above defined mild conditions in the basicdigestion step and the mild bleaching conditions makes it possible to obtain cellulosic material in high yields and high quality as defined in the following.

[0055] After the bleaching step g), the mixture can be cooled down to roomtemperature, and neutralized (step e)) with dilute aqueous acid, preferablyeco:fibr GmbH November 15, 2024119166P1452PC2 acetic acid. The suspension can then be filtered (step d)), and the insolubleresidue, comprising or consisting of cellulosic material, intensively washed withwater (step f)), thereby removing e.g. bleached decomposition products, sodiumacetate, and / or the anti-foaming agent. The obtained insoluble residue usuallyremains as a sludge, i.e., a mixture of insoluble solids and a liquid component, which consists of small amounts of water. The insoluble solids comprise or consist of cellulosic material.

[0056] A further optional step of the process according to the invention is adrying step (step j)) to drying the cellulosic material obtained by the processaccording to the invention described above by standard methods, e.g. byfiltration (step d)) or by pressing (step h)) or by applying heat, or by a combination of one or more drying methods.

[0057] The typical yield of cellulosic material of one process cycle of the processaccording to the invention is between 25 and 40 wt%, or even between 25 and60 wt% based on the dry mass of the starting natural raw material. The obtainedcellulosic material can have a purity of more than 80 wt.%, or more than 85wt.%, or more than 90 wt.%, or more than 95 wt.%, or more than 98 wt% ofcellulose fibers, based on the total weight of the cellulosic material. Preferably, the cellulosic material contains less than 20 wt.%, or less than 15 wt.%, or lessthan 10 wt.%, or less than 5 wt.%, or less than 2 wt% impurities such as lignin,hemicellulose, waxes, or proteins. Residual lignin contents can range between0.6 and 0.9 wt.% in case of bleached pulp, and 2 to 5 wt% in case of unbleachedpulp.

[0058] One embodiment of the process according to the invention is depicted inFigure 1. The process according to the invention is particularly economically viable, if the enzyme bromelain is isolated from the juice obtained by pressing / drying the shredded pineapple raw material, and / or lignin is isolatedfrom the alkaline aqueous solution used for the basic digestion, and / or thealcohol used for extraction is reused after distillation. Both side products, bromelain and lignin, can be sold to the chemical, pharmaceutical or foodeco:fibr GmbH November 15, 2024119166P1452PC2 industry for additional profit. Wastewater can be used in biogas power plants oralso used as fertilizers in agriculture.

[0059] The cellulosic material obtained by the process according to the inventionmainly consists of cellulose fibers. Individual cellulose fiber lengths varybetween 0.5 and 4 mm, and individual cellulose fiber diameters vary between15 and 25 µm. An electron scanning microscopy image of individual cellulosefibers stemming from pineapple plant waste subjected to the process accordingto the invention is shown in Figure 2.

[0060] The cellulosic material obtained by the process according to theinvention, which mainly consists of cellulose fibers, preferably which wasproduced from pineapple plant raw material, is characterized by high strength.In order to test the cellulose fibers in a reliable and reproducible setup, test paper sheets can be produced according to ISO 5263-1:2004 and ISO 5269-2:2004. Cellulosic material obtained by the process according to the invention,preferably exclusively manufactured from pineapple raw material, show tensileenergy absorption (TEA) values of at least 23 J / m2, or of at least 25 J / m2, or ofat least 30 J / m2, or of at least 35 J / m2, or of at least 40 J / m2, and / or up to 45J / m2, or up to 50 J / m2, or up to 55 J / m2, or up to 60 J / m2, or up to 65 J / m2, or up to 70 J / m2, or up to 75 J / m2, or up to 80 J / m2, or up to 85 J / m2, or up to 90 J / m2. In particular TEA values of between 23 to 90 J / m2, or between 25 and 90 J / m2, or between 30 and 85 J / m2, or between 30 and 80 J / m2are achieved.

[0061] Cellulosic material obtained by the process according to the invention,preferably exclusively manufactured from pineapple raw material, show tensileindices of at least 35 Nm / g, or of at least 40 Nm / g, or of at least 45 Nm / g, and / or up to 90 Nm / g, or up to 85 Nm / g, or up to 80 Nm / g, or up to 75 Nm / g, or up to70 Nm / g, or up to 65 Nm / g, or up to 60 Nm / g, or up to 55 Nm / g. In particular, tensile indices of between 35 to 90 Nm / g, or between 40 to 80 Nm / g, or between40 to 60 Nm / g are achieved.

[0062] Cellulosic material obtained by the process according to the invention,preferably exclusively manufactured from pineapple raw material, show burst indices of at least 2.0 kN / g, or of at least 2.5 kN / g, or of at least 3.0 kN / g, and / oreco:fibr GmbH November 15, 2024119166P1452PC2 of at most 3.5 kN / g, or of at most 4.0 kN / g, or of at most 4.5 kN / g, or of at most5.0 kN / g, or of at most 5.5 kN / g, or of at most 6.0 kN / g, or of at most 6.5 kN / g.In particular, burst indices of between 2.0 to 6.5 kN / g, or between 2.5 to 6.0 kN / g, or between 3.0 to 5.5 kN / g are achieved.

[0063] Cellulosic material obtained by the process according to the invention,preferably exclusively manufactured from pineapple raw material, show tensile strains of at least 1.0%, or of at least 1.2%, or of at least 1.5%, and / or at most 2.5%, or at most 2.2%, or at most 2.0%. In particular, tensile strains of between 1.0 to 2.5%, or 1.2 to 2.2% or 1.5 to 2.0% are achieved.

[0064] Cellulosic material obtained by the process according to the invention,preferably exclusively manufactured from pineapple raw material, shows a breaking length of at least 3 km, or of at least 3.5 km, or of at least 4 km, or ofat least 4.5 km, or of at least 5 km, or of at least 5.5 km, and / or up to 8 km, or up to 7.5 km, or up to 7 km, or up to 6.5 km. In particular, a breaking length of between 3 km to 8 km, or between 4 km to 7 km, or between 5 km to 6.5 km is achieved.

[0065] Cellulosic material obtained by the process according to the invention,preferably exclusively manufactured from pineapple raw material, shows a burst pressure of at least 170 kPa, or of at least 180 kPa, or of at least 190 kPa, or ofat least 210 kPa, and / or at most 360 kPa, or at most 340 kPa, or at most 320 kPa, or at most 300 kPa. In particular, a burst pressure of between 170 to 360 kPa, or between 180 to 320 kPa or between 190 to 290 kPa is achieved.

[0066] TEA, tensile indices, burst indices and tensile strains are measuredaccording to DIN EN ISO 1924-2. These mechanical properties of the cellulosicmaterial obtained according to the process of the present invention are superioror at least equal to most other cellulose fibers obtained from various plantprecursors, like wood.

[0067] The mechanical properties of the cellulosic material obtained by theprocess of the invention can be further enhanced by grinding the fibers before paper production. This enhancement is dependent on the grinding time,reaching a maximum after 5 minutes grinding in a Jokro-mill according to DINeco:fibr GmbH November 15, 2024119166P1452PC2 54360. By contrast, cellulosic fibers obtained from pine wood reach theirmaximum mechanical properties after 20 min of grinding.

[0068] Cellulosic material obtained by the process according to the invention,preferably exclusively manufactured from pineapple raw material, and after 5minutes grinding in a Jokro-mill according to DIN 54360 show tensile energyabsorption (TEA) values of at least 70 J / m2, or of at least 75 J / m2, or of at least80 J / m2, or of at least 85 J / m2, or of at least 90 J / m2, and / or up to 100 J / m2, orup to 95 J / m2. In particular TEA values of between 70 to 100 J / m2, or between80 and 95 J / m2 are achieved.

[0069] Cellulosic material obtained by the process according to the invention,preferably exclusively manufactured from pineapple raw material, and after 5minutes grinding in a Jokro-mill according to DIN 54360 show tensile indices ofat least 55 Nm / g, or of at least 60 Nm / g, and / or up to 70 Nm / g, or up to 65 Nm / g.In particular, tensile indices of between 55 to 70 Nm / g, or between 60 to 70Nm / g are achieved.

[0070] Cellulosic material obtained by the process according to the invention,preferably exclusively manufactured from pineapple raw material, and after 5 minutes grinding in a Jokro-mill according to DIN 54360 show tensile strains ofat least 1.0%, or of at least 1.2%, or of at least 1.5%, and / or at most 2.5%, or at most 2.2%, or at most 2.0%. In particular, tensile strains of between 1.0 to 2.5%, or 1.2 to 2.2% or 1.5 to 2.0% are achieved. In particular, the cellulosic materialobtained by the process according to the invention is characterized by a tensile energy absorption (TEA) of at least 25 J / m2, and / or a tensile index of at least 35Nm / g, and / or a maximum strain of not more than 2.5 %, measured according toDIN EN ISO 1924-2 and / or after grinding of the cellulosic material in a Jokro- mill according to DIN 54360 for 5 minutes the cellulosic material is characterized by a tensile energy absorption (TEA) of at least 70 J / m2, and / or a tensile indexof at least 55 Nm / g, and / or a maximum tensile strain of not more than 2.5 %,measured according to DIN EN ISO 1924-2.eco:fibr GmbH November 15, 2024119166P1452PC2

[0071] The cellulosic material obtained by the process according to the inventionis furthermore characterized by high whiteness levels, especially if the fiberswere bleached during the manufacturing process.

[0072] The cellulosic material obtained by the process according to the inventioncan be directly used as substitute of traditional cellulosic material obtained fromwood, e.g., by the paper industry for the production of paper or cardboard. Thecellulosic material can either be used alone, or in a mixture together with cellulose fibers gathered from different sources.

[0073] Thus, further according to the invention is the use of the cellulosicmaterial according to the invention or obtained according to the process of the invention as substitute for cellulosic material stemming from wood. Thus, the cellulosic material according to the invention or obtained according to the process of the invention can be used for manufacturing of an article.

[0074] Further according to the invention is the article comprising or consistingof cellulosic material according to the invention or obtained according to the process of the invention. Such an article can be for example paper, cardboard, tissue, textile, composites, molded pulp, insulation material, nanocellulose orfleece.

[0075] Further according to the invention is also the manufacturing of an articlecomprising or consisting of cellulosic material according to the invention or obtained according to the process of the invention. EXAMPLES

[0076] The invention will be described exemplarily in the following sectionwithout being restricted to the therein disclosed specific embodiments.

[0077] In the following, the process according to the invention is compared toprocesses which are state of the art, namely the soda process and the acetosolv process.

[0078] Process according to the invention (Example 1): 20 kg of pineapplewaste were shredded into 5 x 5 mm particles, immersed in 50 L of an aqueouseco:fibr GmbH November 15, 2024119166P1452PC2 5 % sodium hydroxide solution, and the mixture stirred for 2 hours at 80°C. After neutralization with acetic acid, insoluble solids were filtered off and washed withwater. The thus obtained insoluble solids were then stirred for 1.5 h in 30 L ofwater and then water was removed. The insoluble solids were then added to 21kg of ethanol, and the mixture stirred for 2.5 hours at room temperature. After filtration, the resulting fibrous material was washed with water twice (firstwashing step: 30 L and second washing step: 25 L of water). For bleaching, 120 g of sodium hydroxide were dissolved in 30 L of an aqueous 8.75 % hydrogen peroxide solution (resulting in a pH of 13), and after the fibrous material hasbeen added, the composition was heated to 60°C under stirring and kept as thistemperature for 1.5 hours under stirring. The suspension was neutralized withacetic acid, filtered and the resulting cellulosic material washed with 25 L water and then filtered again.

[0079] Process according to the invention (Example 2):_ 20 kg of pineapplewaste were shredded into 5 x 5 mm particles, immersed in 50 L of an aqueous 5 % sodium hydroxide solution, and the mixture stirred for 2 hours at 90°C. After neutralization with acetic acid, insoluble solids were filtered off and washed with water. The thus obtained insoluble solids were then stirred for 1.5 h in 30 L of water and then water was removed. After filtration, the resulting fibrous material was washed with water twice (first washing step: 30 L and second washing step: 25 L of water). For bleaching, 120 g of sodium hydroxide were dissolved in 30 L of an aqueous 8.75 % hydrogen peroxide solution (resulting in a pH of 13), and after the fibrous material has been added, the composition was heated to 60°C under stirring and kept as this temperature for 1.5 hours under stirring. The suspension was neutralized with acetic acid, filtered and the resulting cellulosic material washed with 25 L water and then filtered again.

[0080] Soda process: 180 g of dried pineapple leaves were shredded into 2x1cm particles, and mixed with 1.8 L of a 2 % aqueous NaOH solution. The mixture was heated to 150°C at a pressure of 4 bar in an autoclave for 2 hours. After the reaction, the insoluble solids were separated from the liquid by filtration and washed with water. The solid was then stirred in water at 800 min-1for 30eco:fibr GmbH November 15, 2024119166P1452PC2 minutes, and the obtained coarse particles (> 1.5 mm) separated from the fine particles by filtration. The fine particles were finally dried to a residual moisture content of 30 wt.%.

[0081] Acetosolv-process: 100 g of dried pineapple leaves were shredded into2x1 cm particles and added to aqueous acetic acid. The mixture was heated to 110 °C, before hydrogen peroxide and phosphoric acid were added. The resulting concentrations of the acetic acid, the phosphoric acid, and the hydrogen peroxide were 74 %, 0.4 %, and 4 % respectively. Boiling continued for 3 h and 15 min, before the mixture was cooled to 0 °C within 30 min. Phase separation was achieved through filtration, and the obtained solid residue was washed with water. The solid was then stirred in water at 800 min-1for 30 minutes, and the obtained coarse particles (> 1.5 mm) separated from the fine particles by filtration. The fine particles were finally dried to a residual moisture content of 30 wt.%.

[0082] As can be seen from the table, the cellulosic material obtained accordingto the process of the present invention shows superior properties, when compared to the soda- or the acetosolv-process.Ex.1 (acco Soda Acetosolv Process rding Ex.2 (according to invention) to the invention) (state of (state of the the art) art) NaOH: 5 %, OH: 98 %, NaOH: 5% NaOH C2H4O2: 74 %, Chemicals used EtH2O2: 4 %,H H2O2 2O2: 8.25 % : 8.25 % (aq): 2 %H3PO4: 0.4 %Temperatur / at most 80 °C / at most 90°C / 150 °C / 110 °C / pressure ambient pressure ambient pressure 4.4 bar ambient pressure Residual content of lignin [wt%]0.75 0.8 0.29 2.6Cellulose content [wt%]85 84 76 78TEA [J / m2][1] 37 n.d. 117 24Tensile index [Nm / g][1]43 n.d. 86 44eco:fibr GmbH November 15, 2024119166P1452PC2 T[1]ensile strain [%]1.46 1.99 2.47 1.09Tensile strength [kN / m][1]3.6 n.d. 6.8 3.5Breaking length [km][1]4.4 5.66 8.8 4.5Burst pressure [kPa][2]187 n.d. 478 207[1] determined according to DIN EN ISO 1924-2; [2] determined according to DIN 53141; n.d. = not determined

[0083] The cellulosic material according to Example 1 is further subjected to agrinding in a Jokro-mill according to DIN 54360. The results are shown in the following table: Grinding time [min] 0 5 10 15TEA [J / m2] 37 93 64 67Tensile index [Nm / g] 43 67 55 55Tensile Strain (%) 1.5 2.5 2.0 2.0

[0084] The maximum of the mechanical properties are achieved already afteronly 5 minutes grinding. The mechanical properties slightly decrease with a grinding time exceeding 5 min, but remain on a rather high constant level.

Claims

eco:fibr GmbH November 15, 2024119166P1452PC2 CLAIMS1. Process for the manufacturing of cellulosic material from natural raw material,comprising the step of basic digestion of the natural raw material, comprisingbringing into contact the natural raw material with an alkaline aqueous solution; wherein no pre-treatment using acid and / or homogenization is conducted.

2. Process according to claim 1, wherein the process further comprises one or moreof the following steps: a) provision of the natural raw material; and / orb) shredding the natural raw material; and / or,c) partially drying the natural raw material; and / ord) filtration; and / ore) neutralization; and / orf) washing; and / org) bleaching; and / orh) pressing; and / ori) washing with at least one alcohol; and / orj) drying; and / ork) recovery of chemicals used in the claimed process, e.g. recovery of theat least one alcohol; l) separation of the enzyme bromelain and / or lignin;m) use of waste water obtained from other steps a) to l), in particular fromsteps c), e) and / or f) for the production of biogas.

3. Process according to claim 1 or 2, wherein the natural raw material comprises notmore than 25 wt.% of lignin and / or wherein the natural raw material comprises atleast 30% by weight of cellulosic material, based on the total dry mass of thenatural raw material.eco:fibr GmbH November 15, 2024119166P1452PC24. Process according to at least one the of claims 1 to 3, wherein the natural rawmaterial comprises plant waste stemming from the species Ananas comosus, preferably comprising the leaves and / or fruit crowns of said plant, flax (Linumusitatissimum), bamboo (Bambusoideae), sugar cane (Saccharum officinarum), Corchorus, kenaf (Hibiscus cannabinus), cannabis, sisal (Agave sisalana), lygeum(Lygeum spartum), ramie (Boehmeria nivea), coconut (Cocos nucifera), Rosa canina, agave (Agave tequilana), or mixtures thereof.

5. Process according to at least one of the claims 1 to 4, wherein the basic digestionis performed in an alkaline aqueous solution with a pH value between 9 and 14,preferably between 10 and 14, and / or at a temperature between 50 and 120 °C,preferably between 60 and 100 °C, more preferably between 70 and 90°C.

6. Process according to at least one the of claims 1 to 5, wherein no chemicalcompounds comprising chlorine or sulfur atoms are used.

7. Process according to at least one the of claims 1 to 6, wherein the insoluble solidsobtained after basic digestion are washed with at least one alcohol, wherein the atleast one alcohol is selected from ethanol, n-propanol, butanol, pentanol, hexanol,cyclohexanol, or a mixture thereof, with the preferred alcohol being ethanol.

8. Process according to at least one the of claims 1 to 7, wherein the alkaline aqueoussolution for the basic digestion is reused multiple times, until the pH of said solutionhas dropped to a value which renders the solution ineffective in further alkalinedigestion steps, preferably until the pH value has dropped below 9.

9. Process according to at least one the of claims 1 to 8, wherein the fibrous material obtained after basic digestion and, optionally, washed with at least one alcohol, isbleached, preferably by treatment of the fibrous material with an alkaline aqueoushydrogen peroxide solution.eco:fibr GmbH November 15, 2024119166P1452PC210. Cellulosic material or cellulosic material obtained by the process according to atleast one of the claims 1 to 9, wherein the cellulosic material is characterized by acellulose content of more than 80 wt.%, preferably more than 85 wt.%, based on the total weight of the cellulosic material, and / or a fiber length of individual cellulosefibers between 0.5 and 4 mm, and / or a fiber diameter of individual cellulose fibersbetween 15 and 25 µm.

11. Cellulosic material according to claim 10, that is characterized by a tensile energyabsorption (TEA) of at least 25 J / m2, and / or a tensile index of at least 35 Nm / g,and / or a maximum strain of not more than 2.5 %, measured according to DIN ENISO 1924-2 and / or after grinding of the cellulosic material in a Jokro-grinder according to DIN 54360 for 5 minutes the cellulosic material is characterized by a tensile energy absorption (TEA) of at least 70 J / m2, and / or a tensile index of atleast 55 Nm / g, and / or a maximum strain of not more than 2.5 %, measuredaccording to DIN EN ISO 1924-2.

12. Use of the cellulosic material as claimed in at least one of the claims 10 or 11, oras manufactured according to at least one of the claims 1 to 9 as substitute forcellulosic material stemming from wood.

13. Use of the cellulosic material as claimed in at least one of the claims 10 or 11, oras manufactured according to at least one of the claims 1 to 9 for manufacturingof an article.

14. Article comprising the cellulosic material as claimed in at least one of the claims10 or 11, or as manufactured according to at least one of the claims 1 to 9,wherein the article can be for example paper, cardboard, tissue, textile, composites, molded pulp, insulation material, nanocellulose or fleece.eco:fibr GmbH November 15, 2024119166P1452PC215. Manufacturing of an article as claimed in claim 14, comprising using a cellulosicmaterial as claimed in at least one of the claims 10 or 11, or as manufacturedaccording to at least one of the claims 1 to 9.

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