Paper pulp comprising a fibrous by-product

Abstract

A process for preparing paper pulp, comprising the following steps: - mixing (E10) a mass percentage of a fibrous by-product (10) with a complementary mass percentage of cellulosic pulp (20), wherein the fibrous by-product (10) comprises at least one of the following: coffee husk obtained from roasting coffee beans, the coffee husk comprising a mass percentage of water-soluble compounds greater than 15% and a mass content of water less than 20%, and textile dust having a length of less than 5 mm; and - refining (E20) the mixture to obtain paper pulp.

Description

TECHNICAL FIELD

[0001] This presentation concerns the general technical field of pulp and paper preparation processes, and that of pulp and paper, in particular packaging papers. STATE OF THE ART

[0002] Papermaking processes transform fibrous raw materials, such as wood fibers, into paper pulp. The paper pulp is then used to produce paper, for example, packaging paper.

[0003] Conventional processes involve manufacturing paper pulp primarily from wood fibers. These processes can be divided into mechanical, chemical, and thermomechanical methods. Each method aims to separate cellulose fibers from components such as lignin and hemicelluloses, while preserving the integrity and length of the fibers to ensure the quality of the final paper. However, these processes have a significant environmental impact due to the felling of trees to obtain the wood fibers and the chemicals used in the corresponding papermaking process.

[0004] To reduce the environmental impact of papermaking, papers can incorporate by-products such as industrial waste, for example, coffee husks generated during coffee roasting. EP 3 440 260 B1 describes a process for manufacturing paper from coffee husks from which the soluble portion has been previously extracted. The coffee husks are refined after extraction and then mixed with wood fibers. US 7 927 460 B1 describes a process for manufacturing paper from coffee husks that have been previously ground in the presence of water. The coffee husks are then mixed with an aqueous suspension of traditional paper pulp fibers.However, these processes are energy-intensive due to the separate processing of coffee husks and the paper pulp with which they are mixed, and are also relatively complex due to the processing of the coffee husks before mixing them with the paper pulp fiber.

[0005] Other papers exist that incorporate textile by-products such as textile scraps or textile fibers. However, these papers have a basis weight exceeding 150 g / m², due to the substantial size of the textile fibers. Furthermore, the textile fibers themselves require pre-treatment before being used to manufacture paper, and their refining is very energy-intensive, again due to the large size of the fibers. GENERAL STATEMENT

[0006] One aim of this application is to address the aforementioned drawbacks by proposing a paper pulp preparation process with reduced environmental impact and reduced cost.

[0007] Another objective of this application is to address the aforementioned disadvantages by proposing a paper pulp, packaging paper or packaging that has a reduced environmental impact and a reduced cost.

[0008] According to one aspect, the present application relates to a process for preparing paper pulp, comprising the following steps: mixing a mass percentage of a fibrous by-product with a complementary mass percentage of a cellulosic pulp, wherein the fibrous by-product comprises at least one of the following: coffee husk obtained from roasting coffee beans, the coffee husk comprising a mass percentage of water-soluble compounds greater than 15% and a mass content of water less than 20%, and textile dust having a length of less than 5 mm; and refining the mixture to obtain paper pulp.

[0009] Cellulose pulp can be obtained by cooking at least one of the following fibers: a wood fiber, an annual plant fiber.

[0010] Wood fiber may include at least one of the following fibers: softwood fiber, hardwood fiber. Annual plant fiber may include at least one of the following fibers: flax fiber, hemp fiber, jute fiber, rice fiber, bagasse fiber, miscanthus fiber.

[0011] The mass percentage of fibrous by-product in the mixture can be between 10% and 60%, for example, it can be between 20% and 40%.

[0012] The coffee film may have an average surface area of ​​less than 2 cm², or even less than 1.5 cm².

[0013] At least 95% of the fibers present in textile dust may have a length of less than 3 mm, or even a length of less than 2 mm.

[0014] During the refining stage, the paper pulp can be refined to have a Schopper-Riegler degree between 55 °SR and 100 °SR, for example between 65 °SR and 85 °SR.

[0015] Cellulosic pulp can be obtained by cooking at least one fiber from an annual plant, the process further comprising at least one pre-mixing step among cooking, peeling, washing and bleaching the fiber from the annual plant in order to obtain the cellulosic pulp.

[0016] The process may also include a post-refining step to purify the paper pulp.

[0017] The process may further include a post-refining step of adding an additive to the paper pulp. The additive may include at least one of the following: a retention agent, a dry strength agent, a wet strength agent, a sizing agent, mineral fillers, or a colorant.

[0018] According to a second aspect, the present application relates to a process for preparing a molded cellulose object, comprising the following steps: preparation of paper pulp by means of a process according to the first aspect; molding of the paper pulp; and drying of the molded paper pulp so as to obtain an object of molded cellulose.

[0019] According to a third aspect, the present application relates to a process for preparing a roll of paper, comprising the following steps: preparation of paper pulp by means of a process according to the first aspect; feeding a headbox of a paper machine with the paper pulp; progressive drainage of the paper pulp on a forming table; drying of the drained paper pulp so as to obtain a strip of paper; and winding of the paper strip onto a mandrel so as to obtain a roll of paper.

[0020] The process for preparing a paper roll may further include a step of applying at least one functional layer to the drained and dried paper pulp, for example, a starch layer, a barrier layer, a sealing layer, or a micro-pigmented layer. The step of applying at least one functional layer may be carried out prior to winding. This step may be carried out on one side only, or alternatively on both sides, of the paper web.

[0021] According to a fourth aspect, the present application relates to paper pulp prepared using the process according to the first aspect.

[0022] Paper pulp can have a Schopper-Riegler degree between 55 °SR and 100 °SR, for example between 65 °SR and 85 °SR.

[0023] According to a fifth aspect, the present application relates to a molded cellulose object obtained using the process according to the second aspect.

[0024] According to a sixth aspect, the present application relates to packaging paper obtained using the process according to the third aspect.

[0025] The wrapping paper can have a basis weight between 10 g / m² and 50 g / m², for example between 18 g / m² and 25 g / m².

[0026] According to a seventh aspect, the present application relates to packaging comprising wrapping paper according to the sixth aspect or an object made of molded cellulose according to the fifth aspect. DESCRIPTION OF THE FIGURES

[0027] There figure 1 represents a block diagram of a paper pulp preparation process according to a first embodiment. figure 2represents a block diagram of a paper pulp preparation process according to a second embodiment compatible with the first embodiment. figure 3 This represents a block diagram of a process for preparing a molded cellulose object, according to one embodiment, from paper pulp. figure 4 represents a block diagram of a process for preparing a roll of paper according to a first embodiment, starting from paper pulp. figure 5 represents a block diagram of a process for preparing a roll of paper according to a second embodiment, from paper pulp. figure 6 represents the length distribution of the ground textile fibers for two samples. figure 7 represents the distribution of textile dust length for a sample.

[0028] Across all figures, similar elements bear identical references. DETAILED DESCRIPTION Manufacturing process

[0029] A process for preparing paper pulp, illustrated by way of non-limiting example in figure 1 includes the following steps: mixture E10 of a mass percentage of a fibrous by-product 10 with a complementary mass percentage of a cellulosic pulp 20, in which the fibrous by-product 10 comprises at least one of the following: coffee husk obtained from roasting coffee beans, the coffee husk comprising a mass percentage of water-soluble compounds greater than 15% and a mass content of water less than 20%, and textile dust having a length of less than 5 mm; and refining E20 of the mixture to obtain paper pulp.

[0030] The paper pulp thus prepared incorporates a fibrous by-product 10, which corresponds to an unrecovered industrial waste product, generated in the case of coffee husks during coffee bean roasting, and in the case of textile dust during the production or processing of a textile product. The paper is therefore manufactured with a reduced environmental impact. Furthermore, the use of the fibrous by-product 10 does not degrade the visual or mechanical properties of the paper.

[0031] When the fibrous by-product 10 is coffee husk, the raw coffee husk—that is, directly from roasting and therefore having a mass percentage of water-soluble compounds greater than 15% and a mass water content less than 20%—can be blended with the pulp 20 without prior chemical or mechanical treatment, in particular without prior mixing with water and grinding. This simplifies and reduces the cost of the papermaking process. Specifically, the coffee husk used for blending has not undergone any extraction of its soluble fraction, grinding in the presence of water, or refining between roasting and blending. Furthermore, the entire coffee husk can be used for blending, which also contributes to reducing the cost of papermaking.

[0032] When the fibrous by-product 10 is textile dust, the raw textile dust—that is, dust directly from the production or processing of the textile product and therefore less than 5 mm in length—can be mixed with the pulp 20 without prior chemical or mechanical treatment. The textile dust can also be the result of shredding textile products. This simplifies and reduces the cost of the paper pulp preparation process. In particular, the textile dust used for the mixture has not undergone any cutting, shredding, defibration, or refining prior to mixing. Furthermore, all of the textile dust can be used for the mixture, which also helps to reduce the cost of paper pulp preparation.Finally, due to the short length of the textile dust, the presence of textile dust in the mixture allows its use in a paper with a reduced basis weight and allows an E20 refining of the mixture to obtain the same level of refining which is less energy costly than refining a mixture which would include a textile fiber.

[0033] Alternatively, textile dust can include textile shredding, that is, ground textile fibers. Textile shredding is obtained by grinding or micronizing textile waste, that is, textile fibers that have been unraveled to be separated into individual fibers. Textile shredding then comprises fibers with a fiber length of less than 5 mm.

[0034] Textile dust can be characterized using optical methods performed in the laboratory, for example, with a fiber measuring device such as the Lorentzen & Wettre Fiber Tester Plus, marketed by the ABB Group. Such characterization allows for the evaluation of fiber length, fiber width, the quantity of fines (particles shorter than 0.2 mm), shape factor, macrofibril content, and coarseness through image analysis. The fiber size of the textile dust is, of course, determined before the E10 mixing step.

[0035] Other methods for measuring the dimensions of textile fibers can be implemented, with fiber length and width being objective quantities.

[0036] Finally, the combined E20 refining of the mixture of fibrous by-product 10 and cellulose pulp 20 to obtain paper pulp provides an energy saving compared to separate refining of the cellulose pulp 20 and the fibrous by-product 10 upstream of their E10 mixture. Furthermore, such combined E20 refining of the mixture better preserves the fiber length of the cellulose pulp 20 used for the same level of refining, particularly in the case of pulp obtained from the cooking of wood fiber, compared to separate refining of the cellulose pulp 20 and the fibrous by-products 10. In addition, the presence of coffee husks in the mixture allows for faster E20 refining, and therefore less energy-intensive, than refining cellulose pulp 20 alone. Coffee film

[0037] The term "coffee skin," or silverskin, refers to a fibrous by-product of coffee bean roasting. It is a thin membrane that surrounds the coffee bean before it is roasted.

[0038] The mass percentage of water-soluble compounds in the raw coffee skin, that is, directly from the manufacturing process in the absence of subsequent chemical or mechanical treatments, is classically greater than 15%, or even greater than 20%, and less than 60%, or even less than 30%.

[0039] The mass water content in the raw coffee skin is classically less than 20%, or even less than 15% or even less than 10%.

[0040] A raw coffee film typically has an average surface area of ​​less than 2 cm², or even less than 1.5 cm².

[0041] A raw coffee film typically has an average thickness of between 20 micrometers and 80 micrometers, particularly between 40 micrometers and 60 micrometers. Textile dust

[0042] The term "textile fiber" refers to a by-product of the production or processing of textile products. It generally originates from textile cutting scraps. Raw textile dust, meaning dust directly from the production or processing of textile products without any subsequent chemical or mechanical treatments, has a length greater than 5 mm, generally greater than 10 mm.

[0043] The term "textile dust" refers to a fibrous by-product 10 resulting from the production, use, or processing of textile products and is generally in the form of a particle smaller than a textile fiber. Textile dust is less than 5 mm long.

[0044] At least 95% of the fibers present in textile dust, particularly in raw textile dust, may be less than 3 mm long. In other words, at least 95% of the particles corresponding to textile dust are less than 3 mm long. The average fiber length in raw textile dust may be less than 2 mm, or even less than 1 mm.

[0045] At least 95% of the fibers present in raw textile dust may have a width of less than 40 micrometers. The average width of the fibers present in raw textile dust may be less than 35 micrometers, or even less than 25 micrometers. The "average" value is defined as the average calculated from a set of measurements of the parameter (width or length) obtained by optical analysis of the fibers in a sample.

[0046] An example of characterization of samples of first-type textile dust (textile dust comprising textile fragments resulting from the shredding of the textile product) or second-type textile dust (textile dust resulting from the production of the textile product) is illustrated in the table below: Average length (mm) Average width (µm) Fines content (%) 1st < type - sample no. 1 0,682 22,73 15,87 1st < type - sample no. 2 0,530 24,10 24,47 1st type - sample no. 3 0,732 23,27 22,77 1st type - sample no. 4 0,993 22,83 10,90 1st type - sample no. 5 0,538 23,45 19,45 2nd type - sample no. 1 1,353 22,57 45,47 2nd type - sample no. 2 0,907 22,33 30,07

[0047] The fines content corresponds to the ratio between the number of fines and the number of fibers measured in the sample. An example of fiber distribution according to fiber length class for these same samples is given in the table below: Fiber distribution according to fiber length class (%) [0.2 mm - 0.5 mm] [0.5 mm - 1.5 mm] [1.5 mm - 3 mm] [3 mm - 5 mm] 1st type - sample no. 1 38,6 57,3 4,1 0,1 1st < type - sample no. 2 56,0 43,1 0,8 0,0 1st type - sample no. 3 41,4 50,5 7,6 0,5 1st type - sample no. 4 20,6 62,2 16,7 0,5 1st type - sample no. 5 53,2 46,3 0,6 0,1 2nd type - sample no. 1 17,3 42,5 36,7 3,5 2nd type - sample no. 2 35,9 49,5 11,6 2,9

[0048] An example of fiber distribution according to fiber width class for these same samples is given in the table below: Fiber distribution according to fiber width class (%) [0 - 20 µm] [20- 25 µm] [25- 30 µm] [30- 40 µm] [40- 80 µm] 1st type - sample no. 1 19,4 49,8 24,3 6,0 0,5 1st < type - sample no. 2 11,6 40,9 33,4 13,3 0,8 1st type - sample no. 3 14,3 48,6 28,6 8,1 0,4 1st type - sample no. 4 17,9 52,3 24,5 5,0 0,4 1st type - sample no. 5 12,8 49,3 31,4 6,2 0,3 2nd type - sample no. 1 31,5 40,6 19,6 7,0 1,3 2nd type - sample no. 2 29,2 41,6 20,5 7,4 1,3

[0049] The percentage of fibers present in raw textile dust with a length of less than 0.2 mm can be greater than 20%, or even greater than 25%. figures 6 And 7illustrate such a distribution for samples no. 1 and no. 2 of the first type of textile dust, and for sample no. 1 of the second type of textile dust.

[0050] The mass water content in raw textile dust is classically less than 20%, or even less than 10%. Fibrous by-product

[0051] The fibrous by-product 10 used for mixing E10 with the cellulosic pulp 20 can correspond to a mass of coffee husks or a mass of textile dust, for example in the form of textile fluff.

[0052] The fibrous by-product 10 used for mixing E10 with the cellulosic pulp 20 may comprise a fibrous by-product 10 of a single type, or alternatively a mixture of different fibrous by-products 10. For example, the fibrous by-product 10 used for mixing may comprise only coffee skins, or only textile dust, or alternatively may comprise a mixture of coffee skins and textile dust. Cellulose pulp

[0053] The term "cellulose pulp" refers to any pulp that can be used to manufacture paper. Cellulose pulp 20 may be obtained by cooking a fiber and may not have undergone any refining prior to mixing E10 with the fibrous by-product 10.

[0054] Cellulose pulp 20 can be obtained by cooking at least one of the following fibers: a wood fiber, an annual plant fiber. The term "annual plant" refers to a plant that completes its life or harvest cycle in a single year or growing season, often in less than twelve months.

[0055] Wood fiber may include at least one of the following fibers: softwood fiber, hardwood fiber. Annual plant fiber may include at least one of the following fibers: flax fiber, hemp fiber, jute fiber, rice fiber, bagasse fiber, miscanthus fiber.

[0056] Cellulose paste 20 can thus be obtained, for example, by isolating the cellulose fibers contained in wood or in an annual plant.

[0057] The cellulose pulp 20 used for the E10 blend can be obtained by boiling a single fiber or a blend of several fibers, including wood and / or annual plant fibers. The type(s) of fiber used to obtain the cellulose pulp 20 can be chosen based on the fiber cost and / or the desired paper properties. For example, the cellulose pulp 20 used for the blend can be pulp obtained solely from wood fibers, or a blend of pulp obtained from boiling wood fibers and pulp obtained from boiling flax or hemp fibers. A cellulose pulp 20 obtained from boiling wood fibers can be used for a wide range of applications, such as printing papers, board, and packaging.A cellulose pulp 20 obtained from the cooking of annual plant fibers such as flax or hemp can be used for paper with a long lifespan, with a lower environmental impact. Blend

[0058] The mass percentage of fibrous by-product 10 in the mixture can be between 10% and 60%, for example, between 20% and 50%, between 30% and 40%, or any value within these ranges. Such mass percentages allow for the production of pulp, and subsequently paper, with satisfactory physical properties, such as satisfactory mechanical strength, processability, tensile strength, and / or durability. The pulp produced by this process can be used to prepare paper suitable for various applications, such as molded cellulose products or packaging paper.

[0059] Mass percentage represents the mass of a component relative to the total mass of a mixture or solution. For example, a mass percentage of 30% for fibrous by-product 10 means that there are 30 kg of fibrous by-product 10 in 100 kg of the total mixture of fibrous by-product 10 and cellulose pulp 20. Therefore, in this case, there will be 70 kg of cellulose pulp 20 in the 100 kg of total mixture.

[0060] For example, the mixture could contain 30% coffee husks by mass and 70% cellulose pulp by mass, for example, pulp obtained from cooking wood fibers. The coffee husks in the mixture would then represent 30% of the total mass of the mixture. Alternatively, the mixture could contain 50% coffee husks by mass and 50% cellulose pulp by mass, for example, pulp obtained from cooking wood fibers. Alternatively, the mixture could contain 30% textile dust by mass and 70% cellulose pulp by mass, for example, pulp obtained from cooking wood fibers. The textile dust in the mixture would then represent 30% of the total mass of the mixture.Alternatively, the mixture may include a mass percentage of textile dust equal to 50% and a mass percentage of cellulose pulp, for example from the cooking of wood fibers, equal to 50%.

[0061] The mass percentage of fibrous by-product 10 can be adjusted according to the desired paper basis weight. For example, for paper with a basis weight of less than 25 g / m², the mass percentage of fibrous by-product 10 can be less than 30%, and for paper with a basis weight greater than 40 g / m², the mass percentage of fibrous by-product 10 can be greater than 30%. Refining

[0062] E20 refining is a mechanical treatment that shortens, hydrates, and fibrillates the fibers in the mixture by applying compression and shear forces. The fibrils increase the bonds between fibers, and the cutting process, which reduces fiber length, improves their distribution within the pulp and ultimately the resulting paper. Refined pulp is thus better suited for preparing molded cellulose products or paper webs for use in papermaking, such as packaging paper.

[0063] E20 refining can be carried out in one or more double-disc refiners and / or one or more conical refiners, for example by means of a continuous flow Claflin refiner and / or by means of a refining stack such as a Jones stack.

[0064] A double-disc refiner comprises a fixed disc and a moving disc, between which the mixture is compressed and sheared to shorten the fibers it contains. A refiner stack comprises a cylinder and one or more rotating blades, between which the mixture passes and is cut to shorten the fibers it contains.

[0065] E20 refining parameters, such as the applied shear effect or refining time, are adjusted to preserve the length and properties of the blended fibers according to the desired Schopper-Riegler degree. This allows the paper pulp containing the refined fibers to be easily drained (E62) and effectively retained on the forming cloth.

[0066] The Schopper-Riegler degree (°SR) indicates the rate at which water can be extracted from a dilute pulp suspension. The Schopper-Riegler degree is measured at the end of the E20 refining process, using any suitable apparatus, for example, an apparatus conforming to ISO 5267-1:2000.

[0067] Paper pulp can have a Schopper-Riegler degree (SR) between 55°SR and 100°SR, for example, between 65°SR and 85°SR, for example, between 70°SR and 80°SR, for example, approximately 75°SR. Such Schopper-Riegler degree ranges correspond to good physical properties of the paper pulp, particularly for molding (E51) and drying (E52) to manufacture molded cellulose products, or for draining (E62) to produce paper webs.

[0068] When the fibrous by-product 10 includes coffee husks, refining E20 can be carried out for a refining time of less than 1 hour 30 minutes, for example, between 45 minutes and 1 hour 15 minutes. The refining time of a mixture comprising coffee husks and cellulose pulp 20 can be shorter than the refining time of cellulose pulp 20 alone. For example, for a mixture comprising a mass percentage of coffee husks equal to 50% and a mass percentage of cellulose pulp 20 obtained from the cooking of wood fibers equal to 50%, a refining time to obtain a Schopper-Riegler degree of 75 °SR can be approximately 50 minutes, whereas the refining time would be approximately 75 minutes for cellulose pulp alone. The presence of coffee skins in the mixture therefore reduces the refining time, and thus the energy consumed by refining E20.The higher the mass percentage of coffee hulls in the blend, the shorter the refining time required to achieve the same level of refinement, i.e., the same Schopper-Riegler degree. Furthermore, for the same level of refinement, the average fiber length in the blend refined with coffee hulls is greater than the average fiber length in the pulp refined alone. The presence of coffee hulls therefore helps maintain fiber length for the same level of refinement. This preserves the mechanical properties of the paper produced from this pulp.For example, at a Schopper-Riegler degree of 73 °SR, the average fiber length of paper pulp refined from an E10 blend of coffee husk and 20% cellulose pulp can range from 0.9 mm to 1.3 mm, compared to less than 1 mm for refined cellulose pulp alone, and the proportion of fibers longer than 1.5 mm is increased. Fibrillation is also improved.

[0069] When the fibrous by-product 10 includes textile dust, refining E20 can be carried out for a refining time exceeding 45 minutes, for example, between 1 and 2 hours. The refining time of a mixture comprising textile dust and cellulose pulp 20 can be substantially equivalent to the refining time of cellulose pulp alone. For example, for a mixture comprising a mass percentage of textile dust equal to 30% and a mass percentage of cellulose pulp 20 obtained from the cooking of wood fibers equal to 70%, a refining time to obtain a Schopper-Riegler degree of 75 °SR can be approximately 1 hour. For the same level of refining, the average fiber length in the refined mixture containing textile dust is greater than the average fiber length in cellulose pulp that would be refined alone.The presence of textile dust thus helps preserve fiber length for the same level of refinement. This allows for the preservation of the mechanical properties of the paper obtained from this pulp. For example, for a Schopper-Riegler degree of 70 °SR, the average fiber length of pulp refined from an E10 mixture of textile dust and 20% cellulosic pulp can be between 1.1 mm and 1.5 mm, compared to a length of less than 1 mm for refined cellulosic pulp alone, and the proportion of fibers longer than 1.5 mm is increased. Fibrillation is also improved.

[0070] E20 refining can be carried out at a dry fiber concentration between 2% and 6%, for example, between 3% and 5%. Dry fiber refers to all the fibers of the fibrous by-product 10 and the fibers of the pulp 20 contained in the paper pulp. The concentration corresponds to the mass of dry fiber, expressed in grams, relative to the total volume of the mixture of dry fiber and liquid, particularly water, present in the paper pulp, expressed in liters. The whole is expressed as a percentage. For example, a dry fiber concentration of 4%, i.e., 40 g / L, corresponds to a mass of 40 g of dry fiber present in a volume of 1 L of paper pulp.

[0071] One or more additional refinements can be carried out, for example in a double-disc refiner and / or a conical refiner. The mixture can undergo each additional refinement one or more times, depending on the desired final properties of the pulp and paper. Purge

[0072] The process may also include a post-refining step (E20) involving the purification (E30) of the paper pulp. This purification (E30) removes impurities, agglomerates, or large particles that may be present in the paper pulp, such as coffee bean residue from the roasting by-product. Such purification (E30) improves paper homogeneity and reduces the potential for machine breakage or other papermaking problems caused by these impurities.

[0073] One or more additional refining steps may, for example, take place after the E30 purification. Adding an additive

[0074] The process may further include a post-refining step E20 of adding an additive E40 to the paper pulp. The addition of one or more E40 additives improves the properties of the paper pulp and / or paper, for example, to facilitate the subsequent manufacture of the paper reel or the molded cellulose object.

[0075] The additive may include at least one of the following: a retention agent, a dry strength agent, a wet strength agent, a bonding agent, mineral fillers, a colorant.

[0076] The addition of the E40 additive can, for example, take place after the E30 purification, and before or after one or more additional refining stages. Cellulose pulp production

[0077] As illustrated by way of non-limiting example in figure 2The process may further include at least one pre-mixing step E10 from among cooking E1, peeling E2, washing E3 and bleaching E4 of the wood or annual plant fiber in order to obtain the cellulosic pulp 20. In particular, when the cellulosic pulp 20 is obtained from cooking at least one annual plant fiber such as flax or hemp fiber, the process may further include at least one pre-mixing step E10 from among cooking E1, peeling E2, washing E3 and bleaching E4 of the annual plant fiber in order to obtain the cellulosic pulp 20.

[0078] The E1 cooking of the fiber can be carried out in a washing machine. E1 cooking parameters, such as cooking time, cooking pressure and / or composition of a cooking solution, can be adapted according to the nature of the fiber to be cooked and the desired properties of the cellulosic pulp 20.

[0079] E2 deburring can be carried out in a deburring stack. E2 deburring allows for an initial shortening of the fibers. Parameters of E2 deburring, such as deburring time, can be adapted according to the nature of the fiber to be deburred and the desired properties of the cellulose pulp 20.

[0080] The E3 wash may include black liquor extraction and / or wash liquor extraction. The wash liquor may consist of a mixture of wash water and sodium hydroxide (NaOH). The E3 wash may be performed during and / or after the E2 deburring.

[0081] E4 bleaching can be carried out in a bleaching machine, and allows lightening and / or purifying cellulose pulp 20, while preserving its fibers. Method for preparing a molded cellulose object

[0082] A process for preparing a molded cellulose object, illustrated by way of non-limiting example in figure 3 includes the following steps: preparation of paper pulp by means of a process as described above; molding E51 of the paper pulp; and drying E52 of the molded paper pulp so as to obtain a molded cellulose object.

[0083] The molded cellulose object preparation process described above offers similar advantages to the paper pulp preparation process described above. In particular, it allows for the preparation of a molded cellulose object using a fibrous by-product 10 without prior treatment of the fibrous by-product 10, and with a less energy-intensive E20 refining of the mixture that better preserves fiber length, for a wide range of molded cellulose object weights. This makes the molded cellulose object preparation process simpler, less expensive, and reduces its environmental impact.

[0084] A molded cellulose object can be obtained using a molded cellulose object preparation process as described above. The molded cellulose object could, for example, be a cellulose tray. Method for preparing a roll of paper

[0085] A method for preparing a roll of paper, illustrated by way of non-limiting example in figure 4 , including the following steps: preparation of paper pulp by means of a process as described above; feeding E61 of a headbox of a paper machine with the paper pulp; progressive draining E62 of the paper pulp on a forming table; drying E63 of the drained paper pulp so as to obtain a paper strip; and winding E64 of the paper strip onto a mandrel so as to obtain a paper reel.

[0086] The paper reel preparation process described above offers similar advantages to the pulp preparation process described above. In particular, it allows for the preparation of a paper reel using a fibrous by-product 10 without prior treatment of the fibrous by-product 10, and with a less energy-intensive E20 refining of the mixture that better preserves fiber length, for a wide range of paper web weights wound onto the core. This makes the paper reel preparation process simpler, less expensive, and reduces its environmental impact.

[0087] A paper machine may include a headbox, a forming table, and one or more presses. The headbox allows the paper pulp to be discharged in a controlled and even manner onto the forming table for drainage (E62). The forming table includes a forming cloth that carries the pulp and allows for the drainage (E62) of water, table rollers that guide and tension the forming cloth, and suction boxes that draw water from the paper pulp. The press(s) remove the water from the paper pulp by compression. The press(s) may include press felts, press rollers, suction boxes, etc.

[0088] Where appropriate, the paper roll manufacturing process described above may include a step of diluting the paper pulp obtained by means of the paper pulp preparation process as described above, in order to obtain the desired dry fiber concentration before feeding E61 into the headbox.

[0089] The progressive E62 draining of paper pulp can be carried out on a flat forming table.

[0090] E63 drying of paper pulp can be carried out in a press and drying section. E63 drying stabilizes the paper pulp into a continuous sheet of paper.

[0091] The E64 winding of the paper strip can be carried out using a winder, in order to form the paper roll.

[0092] Any purification steps E30 and / or the addition of an additive E40 take place after refining E20 and before feeding the headbox with the pulp E61. One or more additional refining steps may take place after purification E30 and before feeding the headbox with the pulp E61.

[0093] The paper roll preparation process may further include a step of applying at least one E65 functional layer, or coating, to the drained and dried paper pulp. Applying at least one E65 functional layer improves the properties of the paper obtained from the drained pulp. This at least one functional layer may, for example, include a starch layer, a barrier layer, a sealing layer, and / or a micro-pigmented layer. In particular, one or more E65 barrier layers may be applied to protect the paper against water, grease, oil, and / or oxygen.

[0094] The application of at least one E65 functional layer can be carried out inline, i.e., without interrupting the manufacturing process, thus optimizing paper roll production. Therefore, and as illustrated by way of non-limiting example in figure 4The application of at least one functional layer E65 can be carried out after the drying step E63, and the process may further include an additional drying step E66 of the paper pulp. This additional drying E66 occurs after the application E65 of the functional layer and before the winding E64 of the paper web onto the mandrel. Specifically, the functional layer is applied E65 to the paper web, then the paper web is dried again during the additional drying step E66, and finally the paper web is wound E64 onto the mandrel.

[0095] Alternatively, or in addition, the application step of at least one E65 functional layer can be performed offline. In this case, and as illustrated by way of non-limiting example in figure 5, the process may further include an unwinding step E67 of the paper web carried out after the winding step E64, then the application step of at least one functional layer E65, then an additional drying step E68, then an additional winding step E69 of the paper web onto a mandrel so as to obtain a paper roll.

[0096] The step of applying at least one E65 functional layer can be carried out on only one of the two faces, or alternatively on both faces, of the paper strip.

[0097] A process for manufacturing a sheet of paper includes obtaining a roll of paper by means of the process described above, and cutting the roll of paper so as to obtain the sheet of paper. Paper pulp, paper, packaging

[0098] Paper pulp can be obtained using a paper pulp preparation process as described above. The paper pulp described is thus obtained more simply, less expensively, and with a reduced environmental impact compared to a conventional process. The paper pulp comprises a refined mixture of a mass percentage of a fibrous by-product 10, such as coffee husks or textile dust, with a complementary mass percentage of cellulose pulp 20. The paper pulp may comprise a mass percentage of fibrous by-product 10 ranging from 10% to 60%, for example, from 20% to 50%, or for example, from 30% to 40%.

[0099] Paper pulp can have a Schopper-Riegler degree (SR) between 55°SR and 100°SR, for example between 65°SR and 85°SR, for example between 70°SR and 80°SR, for example approximately 77°SR. Such Schopper-Riegler degree ranges correspond to good physical properties of the paper pulp, particularly for molding (E51) and drying (E52) to manufacture molded cellulose products, or for draining (E62) to produce paper webs and then paper.

[0100] Paper, especially wrapping paper, can be obtained by means of a paper roll preparation process as described above, with the advantages described above.

[0101] The basis weight of paper corresponds to the ratio between the weight and the surface area of ​​the paper. Basis weight can be measured using any suitable device, for example, a circular shear. Paper obtained using the process described above can have a basis weight ranging from 10 g / m² to 50 g / m², for example, between 20 g / m² and 40 g / m², or between 18 g / m² and 25 g / m². As can be seen from the examples below, the process makes it possible to obtain papers with a basis weight generally between 20 and 30 g / m², or even less than 20 g / m². Such basis weights give the paper good mechanical properties and ease of handling for the user, and allow for a variety of uses, for example, for different types of packaging.

[0102] The paper can have a thickness of between 40 and 60 micrometers.

[0103] The tensile strength of paper represents the force required to break the paper. Tensile strength can be measured by any suitable instrument, for example, a vertical dynamometer. Paper can exhibit a tensile strength measured along its length from 2 daN / 30 mm to 8 daN / 30 mm, for example, from 5 daN / 30 mm to 6 daN / 30 mm. Paper can exhibit a tensile strength measured along its width from 1 daN / 30 mm to 5 daN / 30 mm, for example, from 2 daN / 30 mm to 4 daN / 30 mm, for example, from 2.5 daN / 30 mm to 3.5 daN / 30 mm. Such tensile strength ranges ensure good paper resistance for its end use and converting processes.

[0104] The paper may have a tear resistance measured in the longitudinal direction of the paper between 150 mN and 250 mN, for example between 180 and 220 mN. The paper may have a tear resistance measured in the lateral direction of the paper between 150 mN and 250 mN, for example between 180 and 220 mN.

[0105] The paper can present a differentiating visual appearance, for example with fragments of coffee film or textile dust exhibiting a different shade from the rest of the paper, while maintaining satisfactory homogeneity.

[0106] Packaging may include wrapping paper as described above or a molded cellulose object obtained by means of a molded cellulose object preparation process as described above.

[0107] Although this presentation has been made with reference to specific embodiments, modifications and changes can be made to these examples without departing from its general scope. In particular, individual features of the various embodiments illustrated / mentioned can be combined in additional embodiments. Examples

[0108] The tables below illustrate the characteristics of several papers obtained from coffee husks. The ratios indicated as "XX - YY" with XX+YY = 100 correspond to the percentage of fibrous by-product 10 (XX) - percentage of cellulose pulp 20 (YY). Papers handmade in the laboratory Features Standard Unit 10 -90 20-80 30-70 50-50 Schopper-Riegler Index (SR) ISO 5267-1 75 74 77 82 Weight ISO 536 g / m² 21,9 31,0 21,8 30,8 22,3 30,9 21,9 30,7 Bendtsen permeability ISO 5636-3 ml / min 22 6 77 18 17 5 73 14 Tear ISO 1974 mN 135 192 137 208 99 137 101 155 Tensile strength ISO1924-2 daN / 30mm 5,3 7,3 3,9 6,7 4,4 6,0 3,0 4,9 Elongation ISO1924-2 % 1,7 1,9 1,3 1,6 1,2 1,2 0,8 1,0 Papers made on a paper machine Features Standard Unit 28 - 72 Schopper-Riegler Index (SR) ISO 5267-1 70 Weight ISO 536 g / m² 24,5 19,1 Bendtsen permeability ISO 5636-3 ml / min 69 165 Tear ISO 1974 mN 150 110 Tensile strength ISO1924-2 daN / 30mm 5,0 3,4 Elongation ISO1924-2 % 1,5 1,4

[0109] The table below illustrates the characteristics of several papers obtained from textile dust. The XX - YY ratios indicated correspond to the percentage of fibrous by-product 10 (XX) - percentage of cellulosic pulp 20 (YY). Papers handmade in the laboratory Features Standard Unit 10-90 20-80 30-70 50-50 Schopper-Riegler Index (SR) ISO 5267-1 74 76 55 75 55 87 Weight ISO 536 g / m² 24,9 25,3 19,4 19,3 24,8 19,7 19,2 Bendtsen permeability ISO 5636-3 ml / min 78 80 > 8800 928 151 > 8800 44 Tear ISO 1974 mN 217 206 194 162 1159 152 81 Tensile strength ISO1924-2 daN / 30mm 5,6 4,2 1,9 2,7 3,9 1,5 2,3 Elongation ISO1924-2 % 1,8 1,8 1,2 1,4 1,7 1,4 1,6

Claims

1. A process for preparing paper pulp, comprising the following steps: - mixing (E10) a mass percentage of a fibrous by-product (10) with a complementary mass percentage of a cellulosic pulp (20), wherein the fibrous by-product (10) comprises at least one of the following: coffee husk obtained from roasting coffee beans, the coffee husk comprising a mass percentage of water-soluble compounds greater than 15% and a mass content of water less than 20%, and textile dust having a length of less than 5 mm; and - refining (E20) the mixture to obtain the paper pulp.

2. A process according to claim 1, wherein the cellulosic pulp (20) is obtained from cooking at least one of the following fibers: a wood fiber, an annual plant fiber.

3. A process according to claim 1 or claim 2, wherein the mass percentage of fibrous by-product (10) in the mixture is between 10% and 60%, for example between 20% and 40%.

4. A method according to any one of claims 1 to 3, wherein the coffee film has an average surface area of ​​less than 2 cm² 2 , or even less than 1.5 cm 2 and / or at least 95% of the fibers present in the textile dust have a length of less than 3 mm.

5. A method according to any one of claims 1 to 4, comprising a preliminary step of grinding textile fibers so as to obtain a textile dust comprising ground textile fibers.

6. A process according to any one of claims 1 to 5, wherein, during the refining step (E20), the paper pulp is refined so as to have a Schopper-Riegler degree between 55 °SR and 100 °SR, for example between 65 °SR and 85 °SR.

7. A process according to claim 2, wherein the cellulosic pulp (20) is obtained by cooking at least one fiber from an annual plant, the process further comprising at least one pre-mixing step (E10) from among cooking (E1), peeling (E2), washing (E3) and bleaching (E4) of the annual plant fiber in order to obtain the cellulosic pulp (20).

8. A process according to any one of claims 1 to 7, further comprising a post-refining step (E20) of purifying (E30) the paper pulp.

9. A process according to any one of claims 1 to 8, further comprising a post-refining step (E20) of adding an additive (E40) to the paper pulp, the additive comprising at least one of a retention agent, a dry strength agent, a wet strength agent, a sizing agent, mineral fillers, a colorant.

10. A process for preparing a molded cellulose object, comprising the following steps: - preparing a paper pulp by means of a process according to any one of claims 1 to 9; - molding (E51) the paper pulp; and - drying (E52) the molded paper pulp so as to obtain a molded cellulose object.

11. A method for preparing a paper roll, comprising the following steps: - preparing paper pulp by means of a method according to any one of claims 1 to 9; - feeding (E61) a headbox of a paper machine with the paper pulp; - progressively draining (E62) the paper pulp on a forming table; - drying (E63) the drained paper pulp so as to obtain a paper strip; and - winding (E64) the paper strip onto a mandrel so as to obtain a paper roll.

12. A process according to claim 11, further comprising a step of applying at least one functional layer (E65) to the drained and dried paper pulp, for example among a starch layer, a barrier layer, a sealing layer, a micro-pigmented layer.

13. Paper pulp prepared by means of the process according to any one of claims 1 to 9, wherein the paper pulp has a Schopper-Riegler degree between 55 °SR and 100 °SR, for example between 65 °SR and 85 °SR.

14. Packaging paper obtained by means of the process according to claim 11 or claim 12, wherein the packaging paper has a basis weight of between 10 g / m² 2 and 50 g / m 2 , for example between 18 g / m 2 and 25 g / m 2 .

15. Packaging comprising wrapping paper according to claim 14 or a molded cellulose object obtained by means of a process according to claim 10.

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