Paper pulp comprising cereal straw

Abstract

The present invention relates to a method for manufacturing a paper pulp, comprising the following steps: - mixing (E1) a mass percent of cereal straw (10) of between 20% and 70% with a complementary mass percent of natural fibre or wood fibre (20); - cooking (E2) the mixture in a digester; - slushing (E3) and washing (E4) the pulp; and - refining (E5) the pulp in a beater.

Description

[0001] TITLE: Paper pulp containing cereal straw

[0002] TECHNICAL FIELD

[0003] This presentation concerns the general technical field of manufacturing processes for paper pulp, paper reels and paper sheets, and that of paper pulp and papers, in particular papers for smoking articles.

[0004] STATE OF THE ART

[0005] Papermaking processes transform fibrous raw materials, such as natural or wood fibers, into paper pulp. The pulp is then used to produce a paper roll, which is wound into a paper reel. The reel can then be cut to make sheets of paper and paper products such as smoking materials.

[0006] A smoking product typically consists of a charge, a paper wrapper around the charge, and optionally a filter through which the product is smoked. The charge is designed to generate aerosols when burned and usually contains tobacco. Examples of smoking products include manufactured and roll-your-own cigarettes, as well as cigars.

[0007] The composition and properties of the paper used to form the wrapper of a smoking product influence the speed and evenness of combustion, the smoker's taste, the amount of smoke produced, and the health effects due to the paper's composition and the substances released when it is burned. The paper's composition and properties also influence how easily it can be handled and rolled. Paper also has an environmental impact that varies depending on its composition, manufacturing process, and use.

[0008] Conventional processes involve manufacturing paper pulp primarily from natural fibers or 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 are expensive and dependent on the supply of natural or wood fibers, which are sometimes limited resources and / or subject to significant price fluctuations. Furthermore, these processes have a significant environmental impact due to the felling of trees to obtain wood fibers and the use of chemicals in the corresponding papermaking process.

[0009] Document EP 3 923 749 A1 describes a packaging material for a smoking product. The packaging material comprises pieces extracted from cocoa husks combined with web-building fibers. However, the paper manufacturing process is dependent on the supply of cocoa fibers, a resource that can be limited and / or subject to price fluctuations. Furthermore, the sourcing of cocoa fibers generates a high carbon footprint for companies located in regions of the world where cocoa trees do not grow.

[0010] GENERAL STATEMENT One aim of this application is to remedy the aforementioned disadvantages by proposing a paper pulp manufacturing process with a reduced environmental impact.

[0011] Another objective of this application is to address the aforementioned drawbacks by proposing a roll of paper, a sheet of paper and a smoking or heating article with a reduced environmental impact.

[0012] According to a first aspect, the present application relates to a process for manufacturing paper pulp, comprising the following steps: mixing a mass percentage of cereal straw between 20% and 70% with a complementary mass percentage of natural fiber or wood fiber; cooking the mixture in a washing machine so as to obtain a cooked pulp; peeling and washing the cooked pulp; and refining the peeled and washed pulp in a refining pile.

[0013] The natural fiber may include at least one of the following fibers: hemp fiber, flax fiber, sisal fiber, miscanthus fiber, bamboo fiber.

[0014] Wood fiber may include at least one of the following fibers: softwood fiber, hardwood fiber, eucalyptus fiber.

[0015] Cereal straw may include at least one of the following cereal straws: rice straw, wheat straw, rye straw, barley straw, oat straw.

[0016] The mass percentage of cereal straw can be between 30% and 70%, preferably between 35% and 65%, for example about 50% or about 65%.

[0017] The cooking can be carried out for a cooking time of between 3h and 6h, for example between 4h and 5h30.

[0018] Cooking can be carried out at a cooking pressure between 4 bars and 7 bars, for example between 5 bars and 6 bars.

[0019] The cooking can be carried out in a cooking solution comprising between 8% and 20% sodium hydroxide, for example comprising between 12% and 16% sodium hydroxide.

[0020] The cooking can be carried out in a cooking solution comprising between 5% and 15% sulfites, for example comprising between 7% and 11% sulfites.

[0021] Refining may include a first refining stage and / or a second refining stage.

[0022] The first refining stage can be carried out in a refining stack. This stage can be performed, for example, using one or more double-disc and / or conical refiners, and more specifically, using a refining stack. The first refining stage can be carried out for a duration of between 1 and 4 hours, for example, between 1 and 2 hours. The first refining stage can be carried out at a dry fiber concentration of between 2% and 6%, for example, between 3% and 5%. The second refining stage can be carried out, for example, using one or more double-disc and / or conical refiners. The second refining stage can be carried out for a duration of between 1 and 4 hours, for example, between 1 and 2 hours.The second refining stage can be carried out at a dry fiber concentration of between 1% and 4%, for example between 1.5% and 3%.

[0023] The unwinding step can be performed in a stack. The unwinding step can be performed for a duration of between 1 and 5 hours, for example, between 1 and 3 hours.

[0024] The washing step may include the extraction of black liquors from the pulp. The washing step may include the introduction of water. The washing step may include the extraction of wash liquors. The washing step may include washing the pulp in a bleacher for a washing time of, for example, between 1 and 4 hours, or between 2 and 3 hours.

[0025] According to a second aspect, the present application relates to a process for manufacturing a roll of paper, comprising the following steps:

[0026] - manufacturing paper pulp using a process according to the first aspect;

[0027] - feeding a headbox with paper pulp at a dry fiber concentration of between 0.1% and 0.4%, for example between 0.2% and 0.3%;

[0028] - gradual draining of the paper pulp on a forming table;

[0029] - drying the paper pulp to obtain a strip of paper; and

[0030] - winding the paper strip onto a mandrel to obtain a roll of paper.

[0031] The paper roll manufacturing process may further include a pulp bleaching step, which takes place before feeding the headbox.

[0032] According to a third aspect, the present application relates to a process for manufacturing a sheet of paper for a smoking or heating article, the process comprising obtaining a roll of paper by means of a process according to the second aspect, and cutting the roll of paper so as to obtain a sheet of paper for a smoking or heating article.

[0033] According to a fourth aspect, the present application relates to a paper pulp comprising a mass percentage of cereal straw of between 20% and 70%, for example between 30% and 60%, and a complementary mass percentage of natural fiber or wood fiber, the paper pulp being obtained by means of a process according to the first aspect.

[0034] According to a fifth aspect, the present application relates to a roll of paper obtained by means of a process according to the second aspect, the paper comprising a mass percentage of cereal straw of between 20% and 70%, for example between 30% and 60%, and a complementary mass percentage of natural fiber or wood fiber.

[0035] According to a sixth aspect, the present application relates to a sheet of paper for smoking or heating articles obtained by means of a process according to the third aspect, the sheet of paper comprising a mass percentage of cereal straw of between 20% and 70%, for example between 30% and 60%, and a complementary mass percentage of natural fiber or wood fiber.

[0036] According to a seventh aspect, the present application relates to an article for smoking or heating comprising a sheet of paper according to the sixth aspect and a charge adapted to generate aerosols when burned, the sheet of paper being rolled into a cylinder around the charge.

[0037] DESCRIPTION OF FIGURES Figure 1 represents a block diagram of a paper pulp manufacturing process according to one embodiment.

[0038] Figure 2 represents a block diagram of a process for manufacturing a roll of paper from paper pulp according to one embodiment.

[0039] Across all figures, similar elements bear identical references.

[0040] DETAILED DESCRIPTION

[0041] Manufacturing process

[0042] A process for manufacturing paper pulp, as illustrated by way of non-limiting example in Figure 1, comprises the following steps: mixing E1 of a mass percentage of cereal straw 10 between 20% and 70% with a complementary mass percentage of natural fiber or wood fiber 20; cooking E2 of the mixture in a washing machine so as to obtain a cooked pulp; drawing E3 and washing E4 of the cooked pulp; and refining E5 of the drawn and washed pulp in a refining pile.

[0043] This process makes it possible to manufacture paper by replacing part of the natural fiber or wood fiber with cereal straw, which is an unused agricultural waste product. The paper is therefore produced with a reduced environmental impact.

[0044] Paper pulp made from a mixture containing between 20% and 70% cereal straw by mass produces paper with good mechanical strength, handling characteristics, porosity, tensile strength, durability, and combustion properties. This pulp can be used to manufacture paper suitable for a variety of applications. For example, it can be used to make food-grade baking paper, molded cellulose products, or paper or materials that come into contact with food, such as cellulose trays. It can also be used to manufacture heated products, such as tobacco sticks, or smoking products, such as manufactured cigarettes, rolling cigarettes, or cigars. These cigarettes can be low-flammability cigarettes.

[0045] The paper pulp made from this mixture also results in paper that is free of tobacco or nicotine and has a neutral taste for the user of a smoking article containing this paper, thus helping to improve the user experience.

[0046] Mixing step E1

[0047] Mass percentage represents the mass of a component relative to the total mass of a mixture or solution. For example, a mass percentage of 70% for cereal straw 10 means that there are 70 kg of cereal straw 10 in 100 kg of the total mixture of cereal straw 10 and natural fiber or wood fiber 20. Thus, in the process, the mass percentage of cereal straw 10 is between 20% and 70%, which corresponds to a complementary mass percentage of natural fiber or wood fiber 20 of between 80% and 30%, respectively.

[0048] The natural fiber may include at least one of the following: hemp fiber, flax fiber, sisal fiber, miscanthus fiber, bamboo fiber, cotton fiber, jute fiber, etc. The natural fiber used for the blend may include mixtures of such fibers as hemp, flax, sisal, miscanthus, bamboo, cotton, jute, etc., with the total mass percentage of the mixture of different natural fibers being between 30% and 80%.

[0049] Wood fiber may comprise at least one of the following fibers: softwood fiber, hardwood fiber, eucalyptus fiber, etc. Wood fiber is extracted from the cellulose of wood by chemical processes. The wood fiber used for the blend may comprise mixtures of such softwood, hardwood, eucalyptus, etc. fibers, with the total mass percentage of the mixture of different wood fibers being between 30% and 80%.

[0050] The use of natural fibers or wood fibers can be chosen based on the cost of the fiber and / or the desired properties of the paper. Wood fibers can be used for a wide range of applications, such as newspapers, cardboard, and packaging. Natural fibers can be used for paper with a long lifespan and a lower environmental impact.

[0051] Cereal straw 10 may include at least one of the following cereal straws: rice straw, wheat straw, rye straw, barley straw, or oat straw. Cereal straw 10 is an unrecovered agricultural waste product available in quantity and at low cost. For example, mixture E1 may be a mixture of approximately 50% rice straw by mass with approximately 50% natural hemp fiber by mass.

[0052] The cereal straw 10 used for the mixture may comprise mixtures of straws from different cereals, the total mass percentage of the mixture of different cereal straws 10 being between 20% and 70%. For example, the cereal straw used for the mixture may comprise a mixture of rice straw and wheat straw. For example, the mixture may comprise a mass percentage of cereal straw approximately equal to 50%, of which approximately 25% is rice straw and approximately 25% is wheat straw.

[0053] Cereal straw 10 can be in the form of cereal straw bales 10. The straw bales are conveyed to the leacher by a conveyor for mixing and cooking.

[0054] The mass percentage of cereal straw 10 can be between 30% and 70%, preferably between 35% and 65%, preferably between 45% and 55%, or any range between these values. For example, the mass percentage of cereal straw 10 can be approximately 50%, approximately 55%, approximately 60%, or approximately 65%. Such mass percentages of cereal straw 10 allow for efficient E2 firing and satisfactory E7 rinsing and draining of the cereal straw 10, even in the case of rice straw, for example, which retains a lot of water. Furthermore, such mass percentages of cereal straw allow for the production of pulp and then paper with satisfactory physical properties.

[0055] Cooking stage E2

[0056] The mixture of cereal straw 10 and natural fiber or wood fiber 20 is cooked for example in a washing machine, so as to produce paper pulp.

[0057] The E2 firing can be carried out for a duration of between 3 and 6 hours, for example between 4 and 5.5 hours, for example approximately 5 hours. Such firing durations optimize the E2 firing of the mixture with cereal straw 10, notably by limiting the amount of uncooked cereal straw 10 in the paper pulp and subsequently in the resulting paper.

[0058] The E2 cooking process can be carried out at a cooking pressure between 4 and 7 bars, for example between 5 and 6 bars, for example approximately 5.5 bars. Such cooking pressures optimize the E2 cooking of the mixture with cereal straw 10.

[0059] The E2 firing can be carried out in a firing solution containing between 8% and 20% sodium hydroxide, for example, between 12% and 16% sodium hydroxide, for example, approximately 14% sodium hydroxide. The firing solution may also contain between 5% and 15% sulfites, for example, between 7% and 11% sulfites, for example, approximately 9% sulfites. Such a firing solution is suitable for the E2 firing of the mixture with cereal straw 10, in particular allowing for a reduction in the amount of uncooked cereal straw 10 in the pulp and subsequently in the resulting paper. The sulfites may be, for example, sodium sulfites.

[0060] The E2 cooking process may include several phases of pressure and temperature increase with intermediate degassing.

[0061] The cooked mixture is then drained, for example into the conveyor pile.

[0062] Step E3 for defiling and E4 for washing

[0063] The E3 deburring step can be carried out in a deburring stack. E3 deburring of the dough allows for an initial shortening of the dough fibers, for example after cooking E2 and before refining E5.

[0064] The E3 derolling of the dough can be carried out for a derolling time of between 1 h and 5h, for example between 1 h and 3h, for example equal to about 2h.

[0065] The washing step E4 may include an extraction E41 of black liquors from the pulp.

[0066] The washing step E4 may include an introduction of water E42.

[0067] The washing step E4 may include an extraction E42 of wash liquors. The wash liquors may comprise a mixture of wash water and sodium hydroxide (NaOH).

[0068] The washing step E4 may further include washing the dough in a bleacher E43 for a washing time of between 1 h and 4h, for example between 2h and 3h.

[0069] One or more of the washing substeps E41, E42, E43, E44 described above may be carried out. These substeps may be performed in any order. The washing step E4 may be carried out during and / or after the unwinding step E3.

[0070] Refining stage E5

[0071] E5 refining is a mechanical treatment that shortens, hydrates, and fibrillates the pulp fibers by applying compression and shear forces to the pulp. The fibrils help increase the bonds between fibers, and the cutting process, which reduces fiber length, improves their distribution within the pulp and ultimately the resulting paper. The refined pulp is thus better suited for forming a paper web and for E10 cutting the paper web into sheets.

[0072] The E5 refining stage may include a first refining stage E51 and / or a second refining stage E52. The first refining stage E51 may be carried out using one or more double-disc refiners and / or conical refiners, for example, a refining pile. The refining pile may be a Jones pile. The refining pile comprises a cylinder and one or more rotating blades. During the first refining stage E51, the fibers pass through the refining pile, which allows for initial shortening of the pulp, which is then cut by the rotating blade(s). Parameters of the first refining stage E51, such as the applied shear effect, are adjusted to preserve the fibers from the mixture with cereal straw. Thus, the refined fibers can subsequently be easily drained and effectively retained on the forming cloth.Alternatively, the first refining stage E51 can be carried out in any other suitable refining device, such as a double disc refiner or a conical refiner.

[0073] The first refining step E51 can be carried out for a first refining time of between 1 h and 4h, for example between 1 h and 2h.

[0074] The first refining stage E51 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 cereal straw fibers and natural or wood fibers contained in the pulp. The concentration corresponds to the mass of dry fibers, expressed in grams, relative to the total volume of the mixture of dry fibers and liquid, particularly water, present in the pulp, expressed in liters. The result 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 fibers present in a volume of 1 L of pulp.

[0075] A second refining stage E52 can be carried out using one or more double-disc refiners and / or conical refiners, for example, a double-disc refiner. The double-disc refiner comprises a fixed disc and a moving disc, between which the pulp is compressed and sheared for a second fiber shortening. Alternatively, the second refining stage E52 can be carried out in any other suitable refining device, such as a refining stack. The parameters of the second refining stage E52, such as the applied shearing effect, are adapted to preserve the fibers from the mixture with cereal straw 10. Thus, the refined fibers can subsequently be easily drained and effectively retained on the forming cloth.

[0076] The second refining stage E52 can be carried out for a second refining duration of between 1 h and 4 h, for example between 1 h and 2 h.

[0077] The second refining stage E52 can be carried out at a dry fiber concentration of between 1% and 4%, for example between 1.5% and 3%.

[0078] The dry fiber concentrations during the first refining stage E51 and the second refining stage E52 are lower than the concentrations encountered in paper pulp manufacturing processes based solely on natural fibers or wood fibers 20. Thus, the manufacturing process allows good drainage E7 on the cloth and correct sheet formation, including for pulp containing cereal straw 10 such as rice straw.

[0079] One or more additional refinements may be carried out, for example in a Jones-type refiner pile and / or a double-disc refiner and / or a conical refiner. The pulp may undergo each refinement one or more times, depending on the desired final properties of the cereal straw-based paper.

[0080] 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 using any suitable apparatus, for example, an apparatus conforming to ISO 5267-1:2000. The pulp may have a Schopper-Riegler degree at the end of refining between 40°SR and 100°SR, preferably between 70°SR and 90°SR, for example, approximately 85°SR. Such Schopper-Riegler degree ranges correspond to good physical properties of the paper pulp, particularly for its E7 draining in the production of paper webs.

[0081] Example

[0082] A mass percentage equal to 50% of rice straw is mixed with a complementary mass percentage equal to 50% of natural hemp fiber.

[0083] The mixture is cooked for a cooking time of 5 hours, at a cooking pressure of 5.5 bars, in a cooking solution comprising 14% soda and 9% sulfites.

[0084] After baking E2, the dough is scrolled during scrolling E3 and washed simultaneously during washing E4.

[0085] Then, the first refining stage E51 of the pulp takes place in a refining stack for a first refining time of 1 hour 30 minutes, and at a mass percentage of dry fibers of 4% (40 g / L).

[0086] Then, the second refining stage E52 of the pulp takes place in a double disc refiner, for a second refining time of 1 hour 30 minutes, and at a mass percentage of dry fibers of 2.2%.

[0087] This process allows the production of paper pulp with satisfactory mechanical and porosity properties for the subsequent manufacture of paper for an article such as a smoking article.

[0088] Method for manufacturing a roll of paper and a sheet of paper

[0089] A process for manufacturing a roll of paper, as illustrated by way of non-limiting example in Figure 2, comprises the following steps:

[0090] - manufacturing paper pulp using a paper pulp manufacturing process as described above;

[0091] - feeding E6 of a headbox with paper pulp at a dry fiber concentration between 0.1% and 0.4%, for example between 0.2% and 0.3%;

[0092] - progressive E7 draining of paper pulp on a forming table;

[0093] - drying E8 of the paper pulp to obtain a strip of paper; and

[0094] - winding E9 of the paper strip onto a mandrel to obtain a roll of paper.

[0095] 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 (E7). The forming table includes a forming cloth that carries the pulp and allows the water to drain, table rollers that guide and tension the forming cloth, and suction boxes that draw water from the pulp. The press(s) remove the water from the paper sheet by compression. The press(s) may include press felts, press rollers, suction boxes, etc.

[0096] The concentration of dry fibers in the pulp feeding the headbox for a paper pulp with cereal straw is lower than for a paper pulp containing only natural fibers or wood fibers. This results in a homogeneous fibrous mat and optimizes the formation of the paper sheet from the mixture with cereal straw.

[0097] 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 manufacturing process as described above, in order to obtain the desired dry fiber concentration before feeding the headbox E6.

[0098] The gradual E7 draining of paper pulp can be carried out on a flat forming table. The E7 draining of paper pulp containing cereal straw 10 can be carried out more gradually than the draining of paper pulp containing only natural fibers or wood fibers.

[0099] E8 drying of paper pulp can be carried out in a press and drying section. E8 drying stabilizes the paper pulp into a continuous sheet of paper.

[0100] The E9 winding of the paper strip can be carried out using a winder, in order to form the paper roll.

[0101] The paper strip obtained after E8 drying can be drained again in an additional draining step, and / or can be dried again in an additional drying step.

[0102] The process for manufacturing a paper reel may further include a pulp bleaching step. The bleaching step takes place after the pulp has been manufactured according to the process described above and before the pulp draining step E7, specifically before the feeding step E6 into the headbox.

[0103] A process for manufacturing a sheet of paper, for example a sheet of paper for a smoking or heating article, includes obtaining a roll of paper by means of the process described above, and cutting E10 of the roll of paper so as to obtain a sheet of paper, for example a sheet of paper for a smoking or heating article.

[0104] Paper pulp, paper reel, sheet of paper

[0105] A paper pulp comprising a mass percentage of cereal straw 10 of between 20% and 70%, for example between 30% and 60%, and a complementary mass percentage of natural fiber or wood fiber 20, is obtained by means of a paper pulp manufacturing process as described above.

[0106] The mass percentage of cereal straw 10 in the paper pulp may be between 30% and 70%, preferably between 35% and 65%, preferably between 45% and 55%, or any range between these values. The mass percentage of cereal straw 10 in the paper pulp may, for example, be approximately 50%, approximately 55%, approximately 60%, or approximately 65%. A paper reel is obtained by means of a paper reel manufacturing process as described above, the paper comprising a mass percentage of cereal straw 10 of between 20% and 70%, for example, between 30% and 60%, and a complementary mass percentage of natural fiber or wood fiber 20.

[0107] The mass percentage of cereal straw 10 in the paper may be greater than 35%, for example, greater than 50%, greater than 60%, or greater than 65%. The mass percentage of cereal straw 10 in the paper may be between 30% and 70%, preferably between 35% and 65%, preferably between 45% and 55%, or any range between these values. The mass percentage of cereal straw 10 in the paper may, for example, be approximately 50%, approximately 55%, approximately 60%, or approximately 65%.

[0108] Coresta is a unit of measurement used to express the porosity of tobacco paper, that is, the passage of air through the paper. This unit of measurement corresponds to the airflow rate (expressed in cm³). 3 / min) passing through a 1 cm sample 2of paper, at an applied pressure of 1000 Pa. The paper obtained by the process described above can have a porosity between 5 and 30 Coresta, for example between 5 and 20 Coresta, for example between 7 and 15 Coresta, or any porosity between these values. For example, the paper can have a porosity of approximately 8 Coresta, approximately 10 Coresta, or approximately 12 Coresta. For a smoking article, such porosities provide good combustion quality and delivery of compounds to the user.

[0109] Basis weight (or grammage) refers to the ratio of a paper's surface area to its weight. Basis weight can be measured using any suitable device, for example, a 100 cm² circular saw. 2 The paper obtained using the process described above can have a basis weight of between 5 g / m² 2 and 40 g / m 2 , for example between 10 g / m 2 and 20 g / m2 , for example between 12 g / m 2 and 18 g / m 2 , for example equal to approximately 14 g / m³ 2 Such weights give the paper good mechanical properties and ease of handling for the user.

[0110] Tensile strength represents the force required to break paper. Tensile strength can be measured with any suitable instrument, such as a vertical dynamometer. Paper can have a tensile strength ranging from 1 daN / 30 mm to 5 daN / 30 mm, for example, between 2 daN / 30 mm and 4 daN / 30 mm. Such tensile strength ranges ensure good paper resistance for its end use and converting processes.

[0111] The paper can have a differentiating visual appearance, for example with fragments of cereal straw 10 having a different shade from the rest of the paper, while maintaining a satisfactory homogeneity of the paper.

[0112] A sheet of paper, for example a sheet of paper for a smoking or heating article, is obtained by means of a papermaking process such as that described above. The sheet of paper therefore comprises a mass percentage of cereal straw 10 of between 20% and 70%, for example between 30% and 60%, and a complementary mass percentage of natural fiber or wood fiber 20. The sheet of paper may be a low ignite potential (LIP) paper sheet.

[0113] The sheet of paper could be, for example, a sheet of paper for a manufactured cigarette or a roll-your-own cigarette. The manufactured or roll-your-own cigarette can be a low-flammability cigarette. This reduces the risk of fire, especially if the cigarette is lit but not actively smoked.

[0114] A smoking article comprises a sheet of paper as described above and a suitable charge to generate aerosols when burned, the paper being rolled into a cylinder around the charge. The charge may include tobacco, for example, cut leaf tobacco, reconstituted tobacco material, or mixtures thereof. The charge may also include, as an alternative or in addition to tobacco, other plant material such as plants, herbs, etc.

[0115] A smoking article, such as a cigarette, can be manufactured by placing the filling inside a sheet of paper and rolling the paper around the filling. The sheet of paper then defines an external circumferential surface, forming a container for the filling. The smoking article may further include a filter located at one end of the cylinder formed by the sheet of paper.

[0116] Alternatively or in addition, the sheet of paper as described above can be used to make sleeve paper for coating the filter of smoking articles such as cigarettes.

[0117] An item to be heated could, for example, be a tobacco stick.

[0118] 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.

Claims

DEMANDS 1. A process for manufacturing paper pulp, comprising the following steps: - mixture (E1) of a mass percentage of cereal straw (10) between 20% and 70% with a complementary mass percentage of natural fiber or wood fiber (20); - cooking (E2) of the mixture in a washing machine so as to obtain a cooked paste; - demolding (E3) and washing (E4) of the cooked dough; and - refining (E5) of the dewatered and washed pulp in a refining stack.

2. A method for manufacturing paper pulp according to claim 1, wherein the natural fiber (20) comprises at least one of the following fibers: a hemp fiber, a flax fiber, a sisal fiber, a miscanthus fiber, a bamboo fiber, or wherein the wood fiber (20) comprises at least one of the following fibers: a softwood fiber, a hardwood fiber, an eucalyptus fiber.

3. A method for manufacturing paper pulp according to claim 1 or claim 2, wherein the cereal straw (10) comprises at least one of the following cereal straws: rice straw, wheat straw, rye straw, barley straw, oat straw.

4. A method for manufacturing paper pulp according to any one of claims 1 to 3, wherein the mass percentage of cereal straw (10) is between 30% and 70%, preferably between 35% and 65%, for example is about 50% or is about 65%.

5. A method for manufacturing paper pulp according to any one of claims 1 to 4, wherein the cooking (E2) is carried out for a cooking time of between 3h and 6h, for example between 4h and 5h30, and at a cooking pressure of between 4 bar and 7 bar, for example between 5 bar and 6 bar.

6. A method for manufacturing paper pulp according to any one of claims 1 to 5, wherein the cooking (E2) is carried out in a cooking solution comprising between 8% and 20% of soda, for example comprising between 12% and 16% of soda, the cooking solution further comprising between 5% and 15% of sulfites, for example comprising between 7% and 11% of sulfites.

7. A method for manufacturing paper pulp according to any one of claims 1 to 6, wherein the refining (E5) comprises a first refining step (E51) carried out in a refining stack for a first refining time of between 1 h and 4 h, for example between 1 h and 2 h, at a dry fiber concentration of between 2% and 6%, for example between 3% and 5%, and a second refining step (E52) carried out in a double-disc refiner, for a second refining time of between 1 h and 4h, for example between 1 h and 2h, at a dry fiber concentration of between 1% and 4%, for example between 1.5% and 3%.

8. A method for manufacturing paper pulp according to any one of claims 1 to 7, wherein the uncoiling step (E3) is carried out in an uncoiling stack for a uncoiling time of between 1 h and 5 h, for example between 1 h and 3 h, and wherein the washing step (E4) comprises an extraction (E41) of black liquors from the pulp, an introduction of water (E42), an extraction of washing liquors (E43) and / or a washing of the pulp in a bleacher (E44) for a washing time of between 1 h and 4 h, for example between 2 h and 3 h.

9. A process for manufacturing a roll of paper, comprising the following steps: - manufacturing paper pulp by means of a process according to any one of claims 1 to 8; - feeding (E6) a headbox with paper pulp at a dry fiber concentration of between 0.1% and 0.4%, for example between 0.2% and 0.3%; - progressive draining (E7) of the paper pulp on a forming table; - drying (E8) of the paper pulp to obtain a strip of paper; and - winding (E9) of the paper strip onto a mandrel to obtain a paper roll.

10. Method of manufacturing a sheet of paper for a smoking or heating article, the method comprising obtaining a roll of paper by means of a method according to claim 9, and cutting (E10) the roll of paper so as to obtain a sheet of paper for a smoking or heating article.

11. Paper pulp comprising a mass percentage of cereal straw (10) of between 20% and 70%, for example between 30% and 60%, and a complementary mass percentage of natural fiber or wood fiber (20), the paper pulp being obtained by means of a process according to any one of claims 1 to 8.

12. Paper roll obtained by means of a process according to claim 9, the paper comprising a mass percentage of cereal straw (10) of between 20% and 70%, for example between 30% and 60%, and a complementary mass percentage of natural fiber or wood fiber (20).

13. Paper sheet for smoking or heating article obtained by means of a process according to claim 10, the paper sheet comprising a mass percentage of cereal straw (10) of between 20% and 70%, for example between 30% and 60%, and a complementary mass percentage of natural fiber or wood fiber (20).

14. Article for smoking or heating comprising a sheet of paper according to claim 13 and a charge adapted to generate aerosols when burned, the sheet of paper being rolled into a cylinder around the charge.

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