Paper pulp containing cereal straw

Abstract

This presentation relates to a process for manufacturing paper pulp, comprising the following steps: - mixing (E1) a mass percentage of cereal straw (10) between 20% and 70% with a complementary mass percentage of natural fiber or wood fiber (20); - boiling (E2) of the mixture in a washing machine; - drawing (E3) and washing (E4) of the pulp; and - refining (E5) of the pulp in a refining stack. Figure for the abstract: Fig. 1

Description

Title of the invention: Paper pulp comprising cereal straw. Technical field.

[0001] The present exposition relates to the general technical field of manufacturing processes for paper pulp, paper reels and paper sheets, and to that of paper pulp and papers, in particular papers for smoking articles. STATE OF THE ART

[0002] Papermaking processes allow fibrous raw materials, such as natural fibers or wood fibers, to be transformed into paper pulp. The paper pulp is then used to produce a paper strip wound into a paper reel. The reel can then be cut to make sheets of paper and paper articles such as smoking articles.

[0003] A smoking article generally comprises a charge, a paper wrapper around the charge, and optionally a filter through which the article is smoked. The charge is designed to generate aerosols when burned and typically contains tobacco. Examples of smoking articles include manufactured and roll-your-own cigarettes, as well as cigars.

[0004] The composition and properties of the paper used to form the wrapper of a smoking article influence the speed and uniformity of combustion, the taste for the smoker, the amount of smoke produced, and the health effects due to the paper's composition and the substances released when the paper is burned. The paper's composition and properties also influence how easily the paper can be handled and rolled. The paper also has an environmental impact that varies depending on its composition, manufacturing process, and use.

[0005] Conventional processes consist of manufacturing paper pulp primarily from natural fibers or wood fibers. These processes can be divided into mechanical, chemical, or 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 guarantee the quality of the final paper. However, these processes are costly and dependent on the supply of natural fibers 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 chemicals used in the corresponding papermaking process.

[0006] Document EP 3 923 749 A1 describes a packaging material for a smoking article. 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 supply of cocoa fibers generates a high carbon footprint for companies located in regions of the world where cocoa trees do not grow. GENERAL STATEMENT

[0007] One objective of the present application is to remedy the aforementioned disadvantages by proposing a paper pulp manufacturing process with a reduced environmental impact.

[0008] Another objective of the present application is to remedy the aforementioned disadvantages by proposing a roll of paper, a sheet of paper and a smoking or heating article, which has a reduced environmental impact.

[0009] 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 an additional mass percentage of natural fiber or wood fiber; - cooking the mixture in a washing machine to obtain a cooked paste; - demolding and washing of the cooked dough; and - refining of the processed and washed pulp in a refining stack.

[0010] The natural fibre may include at least one of the following fibre: a hemp fibre, a flax fibre, a sisal fibre, a miscanthus fibre, a bamboo fibre.

[0011] The wood fiber may comprise at least one of the following fibers: a softwood fiber, a hardwood fiber, an eucalyptus fiber.

[0012] Cereal straw may include at least one of the following cereal straws: rice straw, wheat straw, rye straw, barley straw, oat straw.

[0013] The mass percentage of cereal straw can be between 30% and 70%, preferably between 35% and 65%, for example be about 50% or be about 65%.

[0014] The cooking can be carried out for a cooking time of between 3h and 6h, for example between 4h and 5h30.

[0015] The cooking can be carried out at a cooking pressure between 4 bars and 7 bars, for example between 5 bars and 6 bars.

[0016] 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.

[0017] The cooking can be carried out in a cooking solution comprising between 5% and 15% sulfites, for example comprising between 7% and 11% sulfites.

[0018] Refining may include a first refining stage and / or a second refining stage.

[0019] The first refining step can be carried out in a refining stack. The first refining step can be carried out, for example, using one or more double-disc refiners and / or conical refiners, more particularly using a refining stack. The first refining step can be carried out for a first refining time of between 1h and 4h, for example, between 1h and 2h. The first refining step can be carried out at a dry fiber concentration of between 2% and 6%, for example, between 3% and 5%. The second refining step can be carried out, for example, using one or more double-disc refiners and / or conical refiners. The second refining step can be carried out for a second refining time of between 1h and 4h, for example, between 1h and 2h.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%.

[0020] The unwinding step can be performed in a unwinding stack. The unwinding step can be performed during an unwinding time of between Ih and 5h, for example between Ih and 3h.

[0021] 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, for example, between 1 and 4 hours, or for example, between 2 and 3 hours.

[0022] According to a second aspect, the present application relates to a method for manufacturing a roll of paper, comprising the following steps: - manufacturing paper pulp using a process according to the first aspect; - 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%; - progressive draining of the paper pulp on a forming table; - drying of the paper pulp to obtain a strip of paper; and - winding of the paper strip onto a mandrel to obtain a roll of paper.

[0023] The paper roll manufacturing process may further include a pulp bleaching step, which takes place before feeding E6 into the headbox.

[0024] According to a third aspect, the present application relates to a method for 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 the second aspect, and cutting the roll of paper so as to obtain a sheet of paper for a smoking or heating article.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] According to a seventh aspect, the present application relates to a smoking or heating article 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. DESCRIPTION OF THE FIGURES

[0029] Fig. 1 represents a block diagram of a paper pulp manufacturing process according to one embodiment.

[0030] Figure [Fig. 2] represents a block diagram of a process for manufacturing a coil of paper made from paper pulp according to a method of embodiment.

[0031] Throughout the figures, similar elements bear identical references. DETAILED DESCRIPTION Manufacturing process

[0032] A process for manufacturing paper pulp, as illustrated by way of non-limiting example in [Fig. 1], comprises the following steps:

[0033] - mixture El of a mass percentage of cereal straw 10 between 20% and 70% with an additional mass percentage of natural fiber or wood fiber 20;

[0034] - E2 cooking of the mixture in a washing machine so as to obtain a cooked paste;

[0035] - E3 demolding and E4 washing of the cooked dough; and

[0036] - E5 refining of the dewatered and washed pulp in a refining stack.

[0037] This process makes it possible to manufacture paper by substituting part of the fiber natural or wood fiber instead of cereal straw, which is an unused agricultural waste product. The paper is therefore manufactured with a reduced environmental impact.

[0038] Paper pulp made from a mixture containing a mass percentage of cereal straw 10 between 20% and 70% produces paper with good mechanical strength, handling properties, porosity, tensile strength, durability, and combustion properties. The paper pulp produced by this process can be used to manufacture paper suitable for various applications. For example, the paper pulp can be used to manufacture food-grade cooking paper, molded cellulose products, or paper or materials that come into contact with food, such as cellulose trays. The paper pulp can also be used to manufacture, for example, heated articles, such as tobacco sticks, or smoking articles such as manufactured cigarettes, rolling cigarettes, or cigars. The cigarette may be a low-flammability type.

[0039] The paper pulp made from this mixture also makes it possible to produce paper free of tobacco or nicotine and which has a neutral taste for the person who smokes a smoking article including this paper, which helps to improve the experience of the user who smokes it. Mixing step El

[0040] 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.

[0041] The natural fiber may comprise at least one of the following fibers: hemp fiber, flax fiber, sisal fiber, miscanthus fiber, bamboo fiber, cotton fiber, jute fiber, etc. The natural fiber used for the blend may comprise mixtures of such fibers as hemp, flax, sisal, miscanthus, bamboo, cotton, jute, etc., the total mass percentage of the mixture of the different natural fibers being between 30% and 80%.

[0042] The wood fiber may comprise at least one of the following fibers: a softwood fiber, a hardwood fiber, a eucalyptus fiber, etc. The wood fiber is a Fiber extracted from wood cellulose by chemical processes. The wood fiber used for the mixture may include mixtures of such fibers from softwoods, hardwoods, eucalyptus, etc., the total mass percentage of the mixture of different wood fibers being between 30% and 80%.

[0043] The use of natural fibers or wood fibers 20 can be chosen depending 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, for example, newspapers, cardboard, and packaging. Natural fibers can be used for paper with a long lifespan and a lower environmental impact.

[0044] The cereal straw 10 may comprise at least one of the following cereal straws: rice straw, wheat straw, rye straw, barley straw, or oat straw. The cereal straw 10 is an unrecovered agricultural waste product available in quantity and at low cost. For example, the mixture El may be a mixture of approximately 50% rice straw by mass with approximately 50% natural hemp fiber by mass.

[0045] The cereal straw 10 used for the mixture may comprise mixtures of straws from different cereals, the total mass percentage of the mixture of the 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 about 25% is rice straw and about 25% is wheat straw.

[0046] 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.

[0047] 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. The mass percentage of cereal straw 10 can, for example, be approximately 50%, approximately 55%, approximately 60%, or approximately 65%. Such mass percentages of cereal straw 10 allow for efficient cooking E2 and satisfactory rinsing and draining E7 of the cereal straw 10, even in the case, for example, of rice straw, which retains a lot of water. Such mass percentages of cereal straw also allow for the production of pulp and then paper with satisfactory physical properties. Cooking stage E2

[0048] 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.

[0049] The E2 firing can be carried out for a firing time of between 3 and 6 hours, for example between 4 and 5.5 hours, for example approximately 5 hours. Such firing times make it possible to optimize the E2 firing of the mixture with cereal straw 10, in particular by limiting the amount of uncooked cereal straw 10 in the paper pulp and subsequently in the resulting paper.

[0050] 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.

[0051] The E2 firing can be carried out in a firing solution comprising between 8% and 20% sodium hydroxide, for example, between 12% and 16% sodium hydroxide, for example, approximately 14% sodium hydroxide. The firing solution may further comprise 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 limiting the amount of uncooked cereal straw 10 in the paper pulp and subsequently in the resulting paper. The sulfites may be, for example, sodium sulfites.

[0052] The E2 cooking process may include several phases of pressure and temperature increase with intermediate degassing.

[0053] The cooked mixture is then drained, for example into the de-spinning pile. Step E3 of the unwinding process and E4 of the washing process

[0054] The deburring step E3 can be carried out in a deburring stack. Deburring E3 of the pulp allows for an initial shortening of the pulp fibers, for example after cooking E2 and before refining E5.

[0055] The E3 derolling of the dough can be carried out for a derolling time of between Ih and 5h, for example between Ih and 3h, for example equal to about 2h.

[0056] The washing step E4 may include an extraction E41 of black liquors from the pulp.

[0057] The washing step E4 may include an introduction of water E42.

[0058] The washing step E4 may include an extraction E42 of washing liquors. Wash liquors may include a mixture of wash water and sodium hydroxide (NAOH).

[0059] The washing step E4 may further include washing the dough in a bleacher E43 for a washing time of between 1h and 4h, for example between 2h and 3h.

[0060] One or more of the washing substeps E41, E42, E43, E44 described above may be carried out. The washing substeps E41, E42, E43, E44 may be carried out in any conceivable order. The washing step E4 may be carried out during and / or after the unwinding step E3. Refining step E5

[0061] 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 paper pulp and subsequently within the resulting paper. The refined pulp is thus better suited for forming a paper web and for E10 cutting the paper web into sheets of paper.

[0062] Refining E5 may include a first refining stage E51 and / or a second refining stage E52.

[0063] The first refining stage E51 can be carried out using one or more double-disc refiners and / or conical refiners, for example, a refining pile. The refining pile can 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 an 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 protect 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. 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.

[0064] The first refining step E51 can be carried out for a first refining time of between Ih and 4h, for example between Ih and 2h.

[0065] The first refining step E51 can be carried out at a dry fiber concentration of between 2% and 6%, for example, between 3% and 5%. Dry fiber corresponds to all the cereal straw fibers 10 and natural fibers or wood fibers contained in the paper 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, in particular 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 fibers present in a volume of IL of paper pulp.

[0066] A second refining stage E52 can be carried out using one or more double-disc refiners and / or conical refiners, for example, using 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.

[0067] The second refining step E52 can be carried out for a second refining time of between Ih and 4h, for example between Ih and 2h.

[0068] The second refining step E52 can be carried out at a dry fiber concentration of between 1% and 4%, for example between 1.5% and 3%.

[0069] 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 makes it possible to preserve good drainage E7 on the cloth and correct sheet formation, including for a pulp including cereal straw 10 such as rice straw.

[0070] One or more additional refining stages may be carried out, for example in a Jones-type refining pile and / or a double-disc refiner and / or a conical refiner. The pulp may undergo each refining stage once or several times, depending on the desired final properties of the cereal straw-based paper 10.

[0071] 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 manufacture of paper web. Examples

[0072] A mass percentage equal to 50% of rice straw is mixed with a complementary mass percentage equal to 50% of natural hemp fiber.

[0073] 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.

[0074] After cooking E2, the dough is scrolled during scrolling E3 and washed simultaneously during washing E4.

[0075] Then, the first refining step E51 of the pulp takes place in a refining stack for a first refining time of 1h30, and at a mass percentage of dry fibers of 4% (40 g / L).

[0076] Then, the second refining step E52 of the pulp takes place in a double disc refiner, for a second refining time equal to 1h30, and at a mass percentage of dry fibers equal to 2.2%.

[0077] This process allows the obtaining of a paper pulp having satisfactory mechanical and porosity properties for the subsequent manufacture of paper for an article such as a smoking article.

[0078] Method for manufacturing a roll of paper and a sheet of paper

[0079] A method for manufacturing a roll of paper, as illustrated by way of non-limiting example in [Fig.2], comprises the following steps: - manufacturing paper pulp using a paper pulp manufacturing process as described above; - feeding E6 of 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 so as to obtain a strip of paper; and - winding E9 of the paper strip onto a mandrel so as to obtain a roll of paper.

[0080] 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 homogeneous 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) serve to remove the water from the paper sheet by compression. The press(s) may include press felts, press rollers, suction boxes, etc.

[0081] The concentration of dry fibers in the pulp that feeds the headbox for a paper pulp with cereal straw 10 is lower than for a paper pulp containing only natural fibers or wood fibers. Thus, a homogeneous fibrous mat is obtained and the formation of the paper sheet from the mixture with cereal straw 10 is optimized.

[0082] Where appropriate, the process for manufacturing a roll of paper described above may include a step of diluting the paper pulp obtained by means of the process for manufacturing a paper pulp as described above, in order to obtain the desired dry fiber concentration before feeding the headbox E6.

[0083] The progressive E7 draining of the 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 progressively than the draining of paper pulp containing only natural fibers or wood fibers.

[0084] The E8 drying of the paper pulp can be carried out in a press and drying section. The E8 drying process stabilizes the paper pulp into a continuous strip of paper.

[0085] The winding E9 of the paper strip can be carried out using a winder, in order to form the paper roll.

[0086] The paper strip obtained after drying E8 can be drained again in an additional draining step, and / or can be dried again in an additional drying step.

[0087] The process for manufacturing a paper reel may further include a step of bleaching the paper pulp. The bleaching step takes place after the production of the paper pulp according to the process described above and before the draining E7 of the paper pulp, in particular before the feeding E6 of the headbox.

[0088] A method 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.

[0089] Paper pulp, paper reel, sheet of paper

[0090] 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.

[0091] 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%.

[0092] A paper roll is obtained by means of a paper roll manufacturing process as described above, the paper comprising a mass percentage of cereal straw 10 of between 20% and 70%, for example including between 30% and 60%, and an additional mass percentage of natural fiber or wood fiber 20.

[0093] 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%.

[0094] The Coresta is a unit of measurement used to express the porosity of a smoking paper, that is, the passage of air through the smoking paper. This unit of measurement corresponds to the airflow (expressed in cm³ / min) passing through a 1 cm² sample of 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.

[0095] Basis weight corresponds to the ratio between the surface area of ​​paper and its weight. Basis weight can be measured using any suitable device, for example, a 100 cm² circular saw. Paper obtained using the process described above can have a basis weight between 5 g / m² and 40 g / m², for example, between 10 g / m² and 20 g / m², for example, between 12 g / m² and 18 g / m², for example, approximately 14 g / m². Such basis weights give the paper good mechanical properties and ease of handling for the user.

[0096] Tensile strength represents the tensile force required to break the paper. Tensile strength can be measured by any suitable device, for example, a vertical dynamometer. The paper may have a tensile strength between 1 daN / 30 mm and 5 daN / 30 mm, for example, between 2 daN / 30 mm and 4 daN / 30 mm. Such tensile strength ranges ensure good paper strength for its end use and the converting stages.

[0097] The paper may 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.

[0098] A sheet of paper, for example a sheet of paper for a smoking or heating article, is obtained by means of a process for manufacturing a sheet of paper as described above. The sheet of paper therefore comprises a mass percentage of cereal straw 10 between 20% and 70%, for example between 30% and 60%, and a complementary mass percentage of natural fiber or wood fiber 20.

[0099] The sheet of paper may be a sheet of paper with low ignition propensity.

[0100] The sheet of paper could be, for example, a sheet of paper for an industrial cigarette or for a roll-your-own cigarette. The industrial cigarette or the roll-your-own cigarette could be a low-flammability cigarette. Thus, the risk of fire is reduced, particularly if the cigarette is lit without being actively smoked.

[0101] A smoking article comprises a sheet of paper as described above and a charge adapted to generate aerosols when burned, the sheet of paper being rolled into a cylinder around the charge. The charge may comprise tobacco, for example, cut leaf tobacco, reconstituted tobacco material, or mixtures thereof. The charge may comprise, as an alternative or in addition to tobacco, other plant material such as plants, herbs, etc.

[0102] The smoking article, for example a cigarette, can be manufactured by placing the filling inside the sheet of paper and rolling the paper around the filling. The sheet of paper of the smoking article then defines an external circumferential surface forming a container for the filling. The smoking article may further include a filter disposed at one end of the cylinder formed by the sheet of paper.

[0103] Alternatively or in addition, the sheet of paper as described above can be used to manufacture sleeve paper for coating the filter of the smoking article such as the cigarette.

[0104] An article to be heated can, for example, be a tobacco stick.

[0105] Although the present exposition has been carried out with reference to specific embodiments, modifications and changes may be made to these examples without departing from their general scope. In particular, individual features of the various embodiments illustrated / mentioned may be combined in additional embodiments.

Claims

Demands

1. A method for manufacturing paper pulp, comprising the following steps: - mixing (E1) of a mass percentage of cereal straw (10) of between 20% and 70% with an additional 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.

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 of 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 1h and 4h, for example between 1h and 2h, 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 1h and 4h, for example between 1h 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 an uncoiling time of between 1h and 5h, for example between 1h and 3h, 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 1h and 4h, for example between 2h and 3h.

9. A method for manufacturing a paper reel, comprising the following steps: - manufacturing paper pulp by means of a method 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 so as to obtain a paper web; and - winding (E9) of the paper web onto a mandrel so as to obtain a paper reel.

10. A method for 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.