Method for manufacturing flutting and / or liners for corrugated cardboard

Abstract

1. A method for producing fluting and / or liners for corrugated board, comprising the steps of: a) using broke obtained from the production of liners in pulp used for the production of fluting, wherein at least 50% of the broke is unrelated to the production of liners; and / or b) using broke obtained from the production of fluting in pulp used for the production of liners, wherein at least 50% of the broke is unrelated to the production of fluting.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing fluting and / or liners for corrugated cardboard.

Background Art

[0002] Corrugated cardboard (sometimes referred to as corrugated cardboard or corrugated fiberboard) is a packaging material that can be converted into various types of packaging solutions. Corrugated cardboard is a fibrous substrate made of cellulose fibers. The fibers can be virgin fibers or recycled fibers such as those derived from used corrugated cardboard or other materials.

[0003] Corrugated cardboard includes at least one core (fluting) and at least one flat base paper (liner or liner board) adhered to the surface of the core. For example, corrugated cardboard can consist of a layer of fluting adhered between two layers of liners to form a sandwich structure. The sandwich structure can be formed in various forms such as single, double, and triple walls as described, for example, in Kirwan M., J., Paper and Paperboard. Packaging Technology, Blackwell Publishing 2005.

[0004] One problem in producing corrugated cardboard is the adhesion between the liner and the fluting. If the adhesion is too low, delamination occurs, and adding too much adhesive to ensure sufficient adhesion can cause washboard symptoms and curling of the corrugated cardboard. It is important that the adsorption of the added glue to the liner and / or core is optimal. If the adhesive does not adsorb to the fluting / liner, delamination occurs, and the same thing happens if it adsorbs too much to the fluting / liner.

[0005] There are various qualities of corrugated cardboard, which may include different types of linerboard and coreboard. Container cardboard (also known as CCM or corrugated case material) is a type of cardboard specifically manufactured for corrugated cardboard production and includes both the linerboard and coreboard (or fluting), the two types of paper that make up corrugated cardboard. Container cardboard is generally brown as it is made primarily from natural, unbleached wood fibers, but its shade can vary depending on the type of wood, the pulping process, the recycling rate, and the impurity content.

[0006] Examples of different types of liners are kraft liners and test liners. Kraft liners are typically produced from kraft pulp, which can be bleached or unbleached, and may contain one or more layers / plies, where the top layer / ply is often optimized to provide a good print surface and good moisture resistance. Test liners are primarily produced from recycled corrugated cardboard and are usually made with two layers / plies. Due to the presence of recycled fibers, test liners may typically have lower mechanical strength than kraft liners, especially lower burst strength. Kraft liners are often used in packaging boxes where higher strength characteristics are required.

[0007] Fluting is formed from paper or cardboard that has been corrugated using a corrugator with heat, moisture, and pressure.

[0008] Fluting is often prepared from neutral sulfite semi-chemical (NSSC) pulp. NSSC pulp, typically made from hardwoods, is notable for its exceptional rigidity and high hardness, making it suitable for use in fluting. Neutral sulfite semi-chemical (NSSC) pulping is a well-known and long-established process in the field of paper pulping. One reason for using NSSC pulping is its high yield, typically exceeding 60%. In NSSC pulping, the pulp contains sulfites such as Na2SO3 or (NH4)2SO3 and bases such as NaOH or Na2CO3. "Neutral" means that the pH of the NSSC pulp is generally between 6 and 10. The pulp can be pulped in batch or continuous pulping machines. Typically, the pulping time is 5 minutes to 3 hours, and the pulping temperature is 160 to 200°C. NSSC pulp contains a relatively high amount of residual lignin, typically 15-20%, which makes it hard. The Kappa number of NSSC pulp is usually above 70. NSSC pulping is "semi-chemical" in the sense that it also includes mechanical refining of the pulp. Refining can be done, for example, using a disc refiner at digester pressure or atmospheric pressure.

[0009] The fluting and liner are bonded to each other by placing an adhesive between the core and the liner. The liner is bonded to at least one surface of the core by the adhesive. The adhesive is preferably applied to at least one surface of the grooved core, after which the liner is bonded to the surface. Any adhesive conventional in the art can be used. The adhesive may be, for example, a starch-based glue that can be extracted from a wide variety of plants. Some of the most common plants are corn, wheat, barley, rice, potato, tapioca, and pea. The starch is preferably natural, i.e., unmodified starch. The adhesive may also contain water, sodium hydroxide, and boric acid. Other additives may be added, such as additives that improve wet strength or adhesive bond strength. Other functional chemicals, such as borax, glyoxal, or mixtures thereof, may also be added, for example, to improve moisture resistance or gelling behavior.

[0010] One significant challenge when creating corrugated cardboard and cardboard is moisture resistance. When cardboard is exposed to moisture, water and water vapor can diffuse through the liner, causing the cardboard to soften. A common solution to this problem is to increase the basis weight of the fluting and / or liner, but this conflicts with environmental demands for lower basis weight materials that consume less raw materials.

[0011] Another solution is to add a barrier layer to the liner to reduce the permeability of water and water vapor. However, this is simply an incomplete solution because moisture can still diffuse on the opposite side or through the edges, consequently affecting the mechanical stability of the corrugated cardboard. In addition, the barrier layer increases costs and typically reduces the recyclability of the material.

[0012] The fluting or core may also be treated or coated with hydrophobic agents, but this generally increases costs and can negatively affect the mechanical properties of the fluting. High levels of hydrophobic agents can also impair the adhesion between the fluting and the liner. NSSC pulp, in particular, requires high levels of hydrophobic agents to achieve the level of water resistance required in the finished fluting.

[0013] Waste paper refers to partially or completely manufactured paper or board that is discarded from the papermaking, processing, and finishing processes. A significant amount of waste paper is generated during the production of liners, fluting, and corrugated cardboard. Since waste paper can amount to well over 5% of the total output of a machine, it is an important source of fiber, and waste paper processing is an essential part of the papermaking process from a financial and operational standpoint.

[0014] Waste paper is continuously generated, and a “waste paper processing system” is typically implemented to collect, process, and make this resource available for reuse. Waste paper can be wet or dry, depending on where in the process it is obtained. The wet or dry waste paper is then broken down, possibly diluted into a slurry, or stored in waste paper stock for reuse. A waste paper processing system typically includes a waste paper pulper, which is used to break down the waste paper into waste paper stock, which can then be pumped, processed, and subsequently mixed with new stock. The term waste paper pulper can encompass a wide range of machines and may refer to both standalone waste paper pulpers and under-machine (or UTM) pulpers that directly receive paper, including any trim, from the machine. Standalone waste paper pulpers are typically used for processing discarded finished reels or for waste paper that has been packaged or collected for any reason. For efficient waste paper processing and management, monitoring and controlling waste paper chemistry is crucial.

[0015] New machine concepts and increased machine speeds, coupled with the growing demand for resource conservation, further increased the need for pulp with improved properties.

[0016] There remains a need for new and improved fluting and liner materials and methods that combine strength, low basis weight, water / moisture resistance, low chemical consumption, low cost, and / or high recyclability. [Overview of the Initiative]

[0017] The purpose of this disclosure is to provide an improved method for manufacturing corrugated cardboard consisting of liners and fluting that solves or improves at least some of the problems described above.

[0018] A further objective of this disclosure is to provide an improved method for recycling materials when manufacturing corrugated cardboard consisting of liners and flutings.

[0019] A further object of this disclosure is to provide an improved method for manufacturing corrugated cardboard that increases the reuse of waste paper and maintains the quality and properties of the boards produced.

[0020] The purposes described above, as well as other purposes that would be understood by those skilled in the art in light of this disclosure, are achieved by various aspects of this disclosure. [Modes for carrying out the invention]

[0021] Waste paper refers to partially or completely manufactured paper or board that is discarded from the paper or board manufacturing, processing, and finishing processes. Waste paper can be broken down, diluted into a slurry, or stockpiled for reuse. Most commonly, waste paper is reused in the same or the same type of process in which it was produced.

[0022] The use of NSSC pulp in the manufacture of liners is problematic due to the presence of particles and shabs that negatively affect the appearance and optical properties of the liners. This invention is based on the inventive recognition that waste paper obtained from the manufacture of fluting, i.e., recycled material, can be conveniently reused as pulp used for the manufacture of liners. The inventors have also found that waste paper obtained from the manufacture of liners can be conveniently reused as pulp used for the manufacture of fluting for corrugated cardboard.

[0023] The waste paper obtained from fluting production typically contains a higher amount of NSSC pulp than the waste paper from liner production. Using NSSC pulp in liners is desirable because it can offer advantages in terms of improved strength and reduced cost. However, using NSSC pulp in liner production is problematic due to the presence of particles and shives, which typically negatively affect the appearance and optical properties of the liner. The advantage of using NSSC pulp from waste paper compared to using virgin NSSC pulp is that the NSSC pulp from waste paper has undergone additional mechanical and / or chemical treatments that reduce the presence of particles and shives, which negatively affect the appearance and optical properties of the liner. This means that it may be possible to use a higher amount of NSSC pulp from waste paper in liners than virgin NSSC pulp.

[0024] Scrap paper obtained from liner manufacturing typically contains a higher amount of kraft pulp than scrap paper from fluting, which can improve the mechanical strength of the fluting. Since the scrap paper is already refined to an appropriate level, it can help reduce the tendency for cracking in the fluting. Scrap paper obtained from liner manufacturing also typically contains a higher amount of internally added (hydrophobic) sizing agent kraft pulp than scrap paper from fluting, which can improve the water and moisture resistance of the fluting.

[0025] General liners and flutings are made on different equipment, although it is also common for the liner and the fluting to be made on different machines in the same facility.

[0026] According to a first aspect shown herein, A method of manufacturing a fluting and / or a liner for cardboard, comprising: a) using waste paper obtained from the production of the liner in the pulp used for the production of the fluting, wherein at least 50% of the waste paper is waste paper unrelated to the production of the liner; and / or b) using waste paper obtained from the production of the fluting in the pulp used for the production of the liner, wherein at least 50% of the waste paper is waste paper unrelated to the production of the fluting; A method is provided that includes these steps.

[0027] Unrelated waste paper means waste paper resulting from production on another production line, i.e., another paper or cardboard working machine. As a result, the unrelated waste paper is produced at another location or on another production line. Internal waste paper means waste paper produced on the same production line, i.e., the same paper or cardboard working machine. It has been found beneficial to use waste paper from liner production in fluting production and vice versa. For fluting production, it would be preferable for at least 60%, preferably at least 70%, more preferably at least 80%, even more preferably at least 90% of the waste paper to be waste paper unrelated to the production of the liner. For liner production, it would be preferable for at least 60%, preferably at least 70%, more preferably at least 80%, even more preferably at least 90% of the waste paper to be waste paper unrelated to the production of the fluting. From a sustainability and economic perspective, it is still possible to use some amount of internal waste paper for the production of fluting or liner according to the present invention.

[0028] The unrelated waste paper used is obtained from the manufacture of liners or fluting, i.e., not waste paper from ready-made corrugated cardboard containing both liners and fluting.

[0029] Fluting or liners can be manufactured using paper or cardboard machine tools adapted for the manufacture of fluting or liners. Paper or cardboard machine tools for producing fluting and liners are well known in the art. Typically, the machine layout includes a stock processing section, a wet end section, a press section, a drying section, and a calender and / or coating section. In the wet end section, the fluting or liner web is formed by distributing a pulp suspension or stock onto one or more wires using one or more headboxes and partially dewatering them. The resulting fluting or liner web can be single-ply or multi-layered.

[0030] The formed web is typically subjected to further dewatering, which may include, for example, passing the web through the press section of a paper machine, where it passes between large rolls under high pressure to squeeze out as much water as possible. The press section may consist of a traditional nip press unit and press fabric felt, and / or one or more shoe presses or extended dewatering nip. These can operate with various nip or press loads, various positions, temperatures, and delay times. The press section may have one or more shoe presses to maximize production. If one or more shoe presses are used, they can operate at press levels exceeding 800 kN / m, for example, exceeding 1000 kN / m, for example exceeding 1200 kN / m, or for example exceeding 1450 kN / m. The removed water is typically received by the fabric or felt.

[0031] After the pressing section, the web may be subjected to a drying section. Drying may include, for example, passing the web around a series of heated drying cylinders. Drying can typically remove the water content to a level of about 1 to 15 wt%, preferably about 2 to 10 wt%.

[0032] Waste paper is formed from all sections of a paper or cardboard machine and may contain wet or dry material depending on which section it is obtained from.

[0033] The method of this disclosure: a) A process in which waste paper obtained from the production of liners is used in pulp for the production of fluting, wherein at least 50% of the waste paper is waste paper unrelated to the production of liners, or b) A process in which waste paper obtained from the production of fluting is used in pulp for the production of liners, wherein at least 50% of the waste paper is waste paper unrelated to the production of fluting, or Combination of steps a) and b) Includes.

[0034] Typically, liners and flutings are produced using different equipment; however, it is also common for liners and flutings to be produced using different machines within the same facility.

[0035] The method of the present invention is preferably carried out in a plant where both liners and flutings are produced.

[0036] In a plant that produces both liners and flutings, waste paper from each process can be easily reused in the other process; that is, waste paper from the production of liners can be reused as pulp for the production of flutings, and waste paper from the production of flutings can be reused as pulp for the production of liners. In this way, the advantages of both methods can be combined, and waste can be minimized.

[0037] The use of waste paper in steps a) and b) typically involves breaking it down using a waste paper pulper, and optionally diluting the waste paper to form a waste paper stock, which can then be pumped, processed, and mixed with new pulp.

[0038] The waste paper obtained from the production of liners is preferably broken down using a waste paper pulper and optionally diluted to form a waste paper stock, which can be pumped, processed, and then mixed with pulp used for the production of fluting.

[0039] The waste paper obtained from the production of fluting is preferably broken down using a waste paper pulper and optionally diluted to form a waste paper stock, which can then be pumped, processed, and mixed with pulp used for the production of liners.

[0040] Thus, in some embodiments, the waste paper used in steps a) and / or b) is the waste paper stock.

[0041] The waste paper can be broken down, for example, in a vertical or horizontal pulper. The consistency may be, for example, in the range of 2 to 20 wt%, more preferably in the range of 4 to 10 wt%. The broken-down pulp may be further diluted if necessary.

[0042] The pH of the waste paper during decomposition and optional dilution is preferably in the range of 5 to 11, more preferably in the range of 6 to 10. The temperature of the waste paper during decomposition and optional dilution is preferably in the range of 20 to 80°C, more preferably in the range of 30 to 50°C. Before reuse, the waste paper may be deflaked or the fibers may be disintegrated or fibrillated to ensure that no clumps or aggregates of residual flakes or fibers remain. The Schopper Riegler (SR) number of the resulting waste paper stock is determined according to ISO 5267-1 and is preferably in the range of 18 to 50, more preferably in the range of 20 to 45.

[0043] The advantage of using pulp from waste paper compared to virgin pulp is that the pulp from waste paper has already been dehydrated once, thus reducing the presence of colloidal substances and impurities, including electrolytes, in the liquid phase. This reduction can be measured by measuring the conductivity of the waste paper or waste paper stock. In some embodiments, the conductivity of the waste paper is less than 1200, less than 1000, less than 800, or less than 600 when decomposed at 3.5 wt% in distilled water, more preferably less than 500, less than 450, less than 400, less than 350, or less than 300 mS / m.

[0044] The conductivity of the resulting waste paper stock is preferably less than 1200, less than 1000, less than 800, or less than 600, and more preferably less than 500, less than 450, less than 400, less than 350, or less than 300 mS / m.

[0045] In some embodiments, waste paper obtained from the production of liners and flutings is broken down and optionally diluted in a separate waste paper pulper, resulting in pure liner waste paper and pure fluting waste paper, respectively. In some embodiments, internal and unrelated waste paper obtained from the production of liners and flutings is broken down and optionally diluted in a general pulp broker, resulting in a mixture of liner waste paper and fluting waste paper.

[0046] The waste paper obtained from liner production typically contains a higher amount of kraft pulp than the waste paper from fluting. In some embodiments, the waste paper obtained from liner production contains at least 60 wt%, preferably at least 70 wt%, and more preferably at least 80 wt%, of kraft pulp based on the dry weight of the waste paper.

[0047] Waste paper obtained from fluting production typically contains a higher amount of NSSC pulp than waste paper from liners.

[0048] "NSSC pulp" is obtained by "NSSC pulping" and is defined in the background art section. NSSC pulp can be hardwood pulp, softwood pulp, or a mixture thereof. NSSC pulp is preferably a hardwood / softwood pulp mixture containing less than 15 wt% softwood, preferably less than 10 wt% softwood, and more preferably less than 5 wt% softwood. The hardwood may be, for example, aspen, alder, poplar, eucalyptus, birch, acacia, or beech. NSSC pulp is pulped using a pulp containing preferably sulfite, preferably Na2SO3 or (NH4)2SO3, and a base, preferably NaOH or Na2CO3. In some embodiments, the yield from NSSC pulping is greater than 60%, preferably greater than 65%, preferably greater than 70%, and more preferably greater than 75%. The term "neutral" means that the pH of the NSSC pulp is in the range of 6 to 10. The pulping time is preferably in the range of 5 minutes to 3 hours. The pulping temperature is preferably in the range of 160 to 200°C. NSSC pulp may contain a relatively high amount of residual lignin, such as 15 to 20%. The Kappa number of NSSC pulp is typically greater than 70, preferably greater than 80, preferably greater than 95, and more preferably greater than 100, according to ISO 3260. NSSC pulping is "semi-chemical" in the sense that it also includes mechanical refining of the pulp. Refining can be carried out, for example, using a disc refiner at pulping vessel pressure or atmospheric pressure. Refining can be carried out in one or more steps at the same or different pulp consistency. The first refining step may preferably be carried out at a higher consistency, such as 5 to 35%, and the second refining step may preferably be carried out at a lower consistency, such as <5%.

[0049] In some embodiments, the waste paper obtained from the production of fluting includes less than 2%, preferably less than 1.8%, and more preferably less than 1.6% of Pulmac shaves (slot size 0.1 mm).

[0050] In some embodiments, the waste paper obtained from the production of fluting contains at least 30 wt%, preferably at least 40 wt%, and more preferably at least 50 wt%, of NSSC pulp based on the dry weight of the waste paper. In some embodiments, the waste paper obtained from the production of fluting contains at least 60 wt%, preferably at least 70 wt%, and more preferably at least 80 wt%, of NSSC pulp based on the dry weight of the waste paper. This means that the overall kraft pulp content of the fluting increases when waste paper obtained from the production of liners containing at least 60 wt% kraft pulp is added.

[0051] In some embodiments, the pulp used for the production of the liner contains at least 60 wt%, preferably at least 70 wt%, and more preferably at least 80 wt%, of kraft pulp based on the dry weight of the pulp. This means that the overall NSSC pulp content of the liner increases when waste paper obtained from the production of fluting containing, for example, at least 60 wt%, of NSSC pulp.

[0052] Depending on the composition, quality, and availability of the waste paper, various amounts of waste paper can be used. In some embodiments, the amount of waste paper obtained from the production of liners used for pulp for the production of fluting is in the range of 1 to 30 wt%, preferably 5 to 30 wt%, more preferably 1 to 20 wt%, even more preferably 5 to 20 wt%, and even more preferably 10 to 20 wt%, based on the dry weight of the pulp.

[0053] In some embodiments, the amount of waste paper obtained from the production of fluting used for pulp for liner production is in the range of 1 to 30 wt%, preferably 5 to 30 wt%, more preferably 1 to 20 wt%, even more preferably 5 to 20 wt%, and even more preferably 10 to 20 wt%, based on the dry weight of the pulp.

[0054] Efficient waste paper processing and management require monitoring and controlling waste paper chemistry. Prolonged delays, such as downtime, can increase microbial activity within the waste paper. Microbial activity can alter the waste paper chemistry, potentially impacting quality and viability when producing fluting or liners.

[0055] The waste paper used in this disclosure is preferably fresh waste paper. Fresh waste paper means waste paper from fluting or liners that has been decomposed and optionally diluted less than 20 days, more preferably less than 15 days, more preferably less than 5 days, more preferably less than 3 days, and most preferably less than 1 day prior.

[0056] The waste paper used in this disclosure is preferably mill waste paper, i.e., scraps and trim obtained from production at a mill. Mill waste paper can be obtained from various sections of the production process.

[0057] In some embodiments, waste paper from liner production is obtained from the forming section, pressing section and / or drying section.

[0058] In some embodiments, waste paper from the production of fluting is obtained from a forming section, a pressing section, a drying section, and / or a corrugator.

[0059] In some embodiments, the fluting or liner is a multilayer fluting or multilayer liner comprising two outer plies and at least one intermediate ply sandwiched between the outer plies, where waste paper is used in the pulp used to prepare the intermediate ply. Placing the waste paper in the intermediate ply can reduce, for example, the impact of the waste paper on the appearance of the fluting or liner in which it is used.

[0060] In some embodiments, the waste paper obtained from step a) of liner production improves the hydrophobicity of the fluting produced. The waste paper obtained from liner production typically contains a higher amount of internally added (hydrophobic) sizing agent kraft pulp than the waste paper from fluting, which can improve the water and moisture resistance of the fluting.

[0061] In some embodiments, the waste paper from step b) obtained from the production of fluting contains fewer impurities and shives compared to virgin NSSC. Using NSSC pulp in the production of liners is problematic, typically due to the presence of particles and shives that negatively affect the appearance and optical properties of the liners. The advantage of using NSSC pulp from waste paper compared to virgin NSSC pulp is that the NSSC pulp from waste paper has been subjected to additional mechanical and / or chemical treatments that reduce the presence of particles and shives that negatively affect the appearance and optical properties of the liners. This means that it may be possible to use a higher amount of NSSC pulp from waste paper than virgin NSSC pulp.

[0062] A fluting or liner for corrugated cardboard is provided, which can be obtained by a method according to any one of the prior claims, in accordance with a second aspect shown herein.

[0063] The resulting fluting and liner are intended for use in corrugated cardboard. The corrugated cardboard includes at least one layer of uncorrugated liner, which is bonded to at least one layer of fluting. For example, the corrugated cardboard may consist of a layer of fluting sandwiched between two layers of liner.

[0064] Corrugated cardboard including fluting and liner, according to a third embodiment shown herein, i) Fluting including waste paper obtained from the manufacture of liners, wherein at least 50% of the waste paper is unrelated to the manufacture of liners. and / or ii) Liners containing waste paper obtained from the manufacture of fluting, wherein at least 50% of the waste paper is waste paper unrelated to the manufacture of fluting. Cardboard boxes are provided, including the following:

[0065] While the present invention has been described with reference to various exemplary embodiments, as will be understood to those skilled in the art, various modifications can be made without departing from the scope of the invention, and equivalents can be substituted for its elements. In addition, many modifications can be made to adapt the teachings of the invention to specific situations or materials without departing from the essential scope of the invention. Thus, the present invention is not limited to the specific embodiments disclosed as the best possible mode for carrying out this invention, and the present invention is intended to encompass all embodiments that fall within the scope of the appended claims. [Examples]

[0066] Example 1 (Comparison) NSSC beech pulp was obtained in a dry form, then broken down into finishes, and processed at 150 g / m² using a wire mesh pilot paper machine. 2 It was created on a single-ply web. The production speed was 45 m / min, and the finish temperature was 45°C.

[0067] Example 2 (Comparison) The NSSC beech pulp used in Example 1 was refined to a higher SR value, and a web was prepared in the same manner as in Example 1. The increased SR due to the refinement particularly increased the tensile index (Geom).

[0068] Example 3 NSSC beech pulp, as used in Example 1, is washed with water (40 m³ per ton of pulp) using an Eimco belt washing unit. 3The material was washed with fresh water. 2.7% of the fine powder was removed along with colloidal substances and impurities, including electrolytes in the liquid phase. As a result of washing, the pH of the pulp suspension increased, supporting the removal of electrolytes and the reduction of ash content. The web was prepared in the same manner as in Example 1. Small improvements were observed in both tensile strength and elongation.

[0069] Example 4 NSSC beech pulp, as used in Example 1, was mixed with washed NSSC birch waste paper pulp (washed as described in Example 3). The pulps were mixed in a 50-50 ratio. The web was prepared in the same manner as in Example 1. Significant improvements were observed in both tensile strength and elongation.

[0070] Example 5 In this example, washed NSSC birch waste pulp, as used in Example 4, was used without other fibers. The web was prepared in the same manner as in Example 1. The tensile strength properties and elongation were further improved. TIFF0007912027000001.tif76170TIFF0007912027000002.tif93170

[0071] Unless otherwise specified, the physical properties discussed in this disclosure are determined according to the following standards: Whiteness C / 2°+UV ISO 2470-1 L* C / 2°+UV ISO 5631-1 a* C / 2°+UV ISO 5631-1 b* C / 2°+UV ISO 5631-1 Basis weight ISO 536 Thickness, single sheet ISO 534 Umbrella, single sheet ISO 534 Air permeability GH ISO 5636-5 Cobb 30s ISO 535 Moisture content 50%rh ISO 287 Scott-Bond TAPPI T569 Tensile strength ISO 1924-3 Tensile index ISO 1924-3 Tensile strength md / cd ISO 1924-3 Elongation ISO 1924-3 Tensile stiffness ISO 1924-3 Tensile stiffness index ISO 1924-3 E - Modulus of Elasticity ISO 1924-3 TEA ISO 1924-3 TEA index ISO 1924-3 TEA index ISO 1924-3 Fracture toughness ISO / TS 17958 Fracture toughness index ISO / TS 17958 Tear resistance ISO 1974 Tear index ISO 1974 SCT ISO 9895 SCT index ISO 9895 RCT ISO 12192 RCT index ISO 12192 Rupture Index ISO 2759 Bursting strength ISO 2759

[0072] Unless otherwise specified, standard methods can be applied to determine the physical and mechanical properties in both the cross direction (cd) and the longitudinal direction (md).

Claims

1. A method for manufacturing flutting and / or liners for corrugated cardboard, a) A process in which waste paper obtained from the production of liners is used in pulp for the production of flutes, wherein at least 50 wt% of the waste paper is waste paper unrelated to the production of liners, and the amount of waste paper obtained from the production of liners used in pulp for the production of flutes is in the range of 1 to 30 wt% based on the dry weight of the pulp. and / or b) A step in which waste paper obtained from the production of fluting is used in pulp for the production of liners, wherein at least 50 wt% of the waste paper is waste paper unrelated to the production of fluting, and the amount of waste paper obtained from the production of fluting used in pulp for the production of liners is in the range of 1 to 30 wt% based on the dry weight of the pulp. Methods that include...

2. The method according to claim 1, comprising step a).

3. The method according to claim 1, comprising step b).

4. The method according to claim 1, comprising steps a) and b).

5. The method according to any one of claims 1 to 4, wherein the amount of waste paper obtained from the production of liners, used for pulp for the production of fluting, is in the range of 5 to 20 wt% based on the dry weight of the pulp.

6. The method according to any one of claims 1 to 4, wherein the amount of waste paper obtained from the production of fluting, used for pulp for the production of liners, is in the range of 5 to 20 wt% based on the dry weight of the pulp.

7. The method according to any one of claims 1 to 4, wherein the waste paper is mill waste paper.

8. The method according to any one of claims 1 to 4, wherein the waste paper from the production of fluting is obtained from a forming section, a pressing section, a drying section, and / or a corrugator.

9. The method according to any one of claims 1 to 4, wherein the waste paper from the manufacture of the liner is obtained from a forming section, a pressing section and / or a drying section.

10. The method according to any one of claims 1 to 4, wherein the fluting or liner is a multilayer fluting or multilayer liner comprising two outer plies and at least one intermediate ply sandwiched between the outer plies, and the waste paper is used for pulp used to prepare the intermediate plies.

11. The method according to any one of claims 1 to 4, wherein the waste paper obtained in step a) from the manufacture of the liner improves the hydrophobicity of the fluting produced.

12. Corrugated cardboard including fluting and liner, the corrugated cardboard is i) Fluting comprising waste paper obtained from the production of liners, wherein at least 50 wt% of the waste paper is waste paper unrelated to the production of liners, and the amount of waste paper obtained from the production of liners used for the production of fluting is in the range of 1 to 30 wt% based on the dry weight of the pulp. and / or ii) Liners comprising waste paper obtained from the production of fluting, wherein at least 50 wt% of the waste paper is waste paper unrelated to the production of fluting, and the amount of waste paper obtained from the production of fluting used for the production of liners is in the range of 1 to 30 wt% based on the dry weight of the pulp, Cardboard, including.

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