Multilayer paper, use of same and container

Abstract

The present invention relates to a paper comprising (a) an outer layer comprising bleached short cellulose fiber, (b) a core layer comprising about 70% to about 90% by weight of bleached short cellulose fiber and about 10% to about 30% by weight of bleached short fiber chemi-thermomechanical pulp, and (c) an inner layer comprising bleached short cellulose fiber. The paper may comprise one or more additional barrier layers. The barrier layer(s) applied to the outer, core, and / or inner layer of the paper may comprise a resin, a release agent, an additive to increase the coefficient of friction, and / or low-density polyethylene (LDPE). The paper of the present invention is suitable for forming containers for liquids or food. A container made from the paper of the present invention is also disclosed.

Description

MULTILAYER PAPER, ITS USE AND CONTAINER FIELD OF INVENTION

[0001] The present invention relates to a paper comprising (a) an outer layer comprising bleached hardwood pulp, (b) a core layer comprising about 70% to about 90% by weight of bleached hardwood pulp and about 10% to about 30% by weight of bleached hardwood pulp, and (c) an inner layer comprising bleached hardwood pulp. The paper may comprise one or more additional barrier layers. The barrier layer(s) applied to the outer, core, and / or inner layer of the paper may comprise a resin, a release agent, an additive to increase the coefficient of friction, and / or low-density polyethylene (LDPE). The paper of the present invention is suitable for forming containers for liquids or foods. Also disclosed is a container obtained from the paper of the present invention. BACKGROUND OF THE INVENTION

[0002] When it comes to containers / packaging for liquids and food, there's a market trend toward replacing plastic with paper. However, this substitution is associated with significant challenges. Plastic has good elongation, flexibility, and tensile strength, and doesn't tear easily. Paper, on the other hand, behaves very differently.

[0003] The papers currently on the market have low mechanical strength, but some use long fibers to improve this property, as long fiber provides properties suitable for this application. Another disadvantage of the papers currently on the market is that they are thicker than plastic films, which makes it impossible to form the final packaging, causing cracks in the fiber and consequently losing strength and barrier properties when polymeric material is applied to establish sealing and barrier properties, whereas the base paper alone lacks these properties.

[0004] In this context, document BR 112012000100-0, for example, refers to a laminated packaging material for a container comprising a paper substrate layer and at least one other layer containing at least one linear low-density polyethylene. The laminated packaging material for liquid food containers described in this document comprises an outermost layer of thermoplastic material, a paper substrate layer, and an innermost layer of thermoplastic material, the innermost layer of thermoplastic material comprising a blend of a linear low-density polyethylene and a low-density polyethylene. According to with the document, it is an advantage to use mixtures of these two polymers, as it provides a low thickness of the innermost layer of the thermoplastic material.

[0005] In the state of the art, there is a need to obtain paper containers for liquids and food that are biodegradable, recyclable and compostable, but at the same time possessing good mechanical properties.

[0006] To replace plastic containers / packaging with paper containers / packaging, the present invention developed a biodegradable, recyclable, and compostable multilayer paper, comprising 100% short fibers and possessing good strength. This paper can be coated with barrier layers, providing good sealing and a barrier to liquids and grease. The paper developed in the present invention comprises a significant amount of renewable source material (natural fibers) and can be applied in various processes. SUMMARY OF THE INVENTION

[0007] Described herein is a base paper comprising (a) an outer layer comprising bleached hardwood pulp; (b) a flute layer comprising about 70% to about 90% by weight of bleached hardwood pulp and about 10% to about 30% by weight of bleached hardwood pulp, based on the total dry weight of the flute layer in the paper; and (c) an inner layer comprising bleached hardwood pulp.

[0008] The fiber comprised in the paper of the present invention is 100% short hardwood fiber, preferably eucalyptus fiber.

[0009] In one embodiment of the invention, the base paper has the following fiber length distribution, based on dry weight: i. 0 to 0.2 mm: 9.90 to 12.20%; ii. 0.2 to 0.6 mm: 18.30 to 21.90%; iii. 0.6 to 1.2 mm: 63.10 to 66.70%; iv. 1.2 to 2.0 mm: 3.90 to 6.70%; and v. 2.0 to 3.2 mm: 0.10 to 0.40%.

[0010] Fiber lengths were measured according to ISO 16065-2:2014.

[0011] In one embodiment of the invention, the base paper comprises natural starch between the layers.

[0012] In one embodiment of the invention, one or more of the layers of the base paper comprise(s) additives selected from cationic starch, oxidized starch and a sizing agent.

[0013] In one embodiment of the invention, the base paper has a grammage of about 200 g / m 2 at about 300 g / m 2 , in which the outer layer and the inner layer have a weight of approximately 50 g / m 2 each, and the paper weight was measured in accordance with ISO 536:2012.

[0014] The base paper of the present invention has: i. tensile strength L of about 10 kN / m to about 20 kN / m; ii. elongation L of about 1.3 mm to about 2.5 mm; iii. TEA L of about 150 J / m 2 at about 300 J / m 2; iv. tensile strength T of about 7 kN / m to about 12 kN / m; v. elongation T of about 4 mm to about 8 mm; and / or vi. TEA T of about 280 J / m 2 at about 500 J / m 2 ; where tensile strength L, elongation L, TEA L, tensile strength T, elongation T and TEA T are measured according to ABNT - NBR ISO 1924-3:2006.

[0015] In a preferred embodiment of the invention, the paper is cardboard.

[0016] The paper of the present invention may additionally comprise one or more barrier layers.

[0017] In one embodiment of the invention, the paper comprises: - a barrier layer of 4 to 6 g / m 2 applied to the outer layer, wherein the barrier layer comprises a resin and optionally a release agent and / or an additive to increase the coefficient of friction; - a barrier layer of 3 to 5 g / m 2applied to the inner layer, where the barrier layer comprises a resin; - a barrier layer of 4 to 6 g / m 2 applied to the inner layer, where the barrier layer comprises a resin, a release agent and an additive to increase the coefficient of friction.

[0018] In another embodiment of the invention, the paper comprises: - a barrier layer of 12 to 16 g / m 2 applied to the outer layer, where the barrier layer comprises LDPE polyethylene; and - a barrier layer of 16 to 20 g / m 2 applied to the inner layer, where the barrier layer comprises polyethylene LDPE.

[0019] In another embodiment of the invention, the paper comprises: - a barrier layer of 16 to 20 g / m 2 applied to the inner layer, where the barrier layer comprises polyethylene LDPE.

[0020] In one embodiment of the invention, the base paper comprising barrier layers is for forming containers for liquids or foods.

[0021] Also described in the present invention is the use of the base paper comprising barrier layers of the invention for the production of containers for liquids or food, preferably for immediate consumption.

[0022] A container made from the paper of the present invention is also described. The container can be a cup, a container, a lunch box, a food box, or a jar. The container is for liquids or foods, such as coffee, juice, soda, dry and fatty foods, popcorn, and ice cream. In a preferred embodiment, the container is for liquids or foods for immediate consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 01 represents the multilayer base paper of the present invention.

[0024] Figure 02 represents the base paper of the present invention coated with biodegradable barrier layers, according to one of the embodiments of the present invention.

[0025] Figure 03 represents the base paper of the present invention coated with a polymer barrier layer in the inner layer, according to one of the embodiments of the present invention.

[0026] Figure 04 represents the base paper of the present invention coated with polymer barrier layers in the inner and outer layers, according to one of the embodiments of the present invention.

[0027] Figure 05 refers to the weights of samples 1 to 11 of base paper of Example 2 of the present invention.

[0028] Figures 06 to 11 represent graphs of the mechanical properties of samples 1 to 11 of base paper of Example 2 of this invention. Particularly, Figure 06 refers to Tensile Strength L, Figure 07 refers to Elongation L, Figure 08 refers to TEA L, Figure 09 refers to Tensile Strength T, Figure 10 refers to Elongation T and Figure 11 refers to TEA T.

[0029] Figure 12 represents a graph of pH values ​​monitored during the biodegradability test of Example 3.

[0030] Figure 13 represents a graph of moisture percentages monitored during the biodegradability test of Example 3.

[0031] Figure 14 represents a graph of the percentage of Biodegradability during the test period for the sample in Example 3.

[0032] Figure 15 (a) refers to the organic compound after sieving (2 mm sieve) and Figure 15 (b) refers to the remaining sample after sieving (2 mm sieve), from the compostability test of Example 3.

[0033] The paper of the present invention is a biodegradable, recyclable, and compostable multilayer paper that uses only short fibers. This paper (also called base paper) may or may not be coated with barrier layers.

[0034] The base paper of the present invention comprises: (a) an outer layer comprising bleached short cellulose fiber; (b) a fluting layer comprising about 70% to about 90% by weight of bleached hardwood pulp and about 10% to about 30% by weight of bleached hardwood chemithermomechanical pulp, based on the total dry weight of the fluting layer in the paper; and (c) an inner layer comprising bleached short cellulose fiber.

[0035] The outer layer may also be called the cover side, felt side, or lining side. The inner layer may also be called the back side, canvas side, or backing side.

[0036] The bleached short fiber chemithermomechanical pulp contained in the core layer gives the paper rigidity and bulk.

[0037] The fibers comprised in all layers of the paper of the present invention are 100% short hardwood fibers, preferably eucalyptus fibers. In a preferred embodiment, the fibers are bleached virgin eucalyptus fibers.

[0038] The larger the fiber size, the larger the contact surface and the greater the strength of the paper comprising it. However, although the paper of the present invention does not employ long fibers, either alone or in a mixture with short fibers, it was possible to achieve, in the present invention, a paper with good strength and good mechanical properties.

[0039] The fiber length distribution contributes to the strength of the paper of the present invention, as it allows for better interlacing and greater bond strength between the fibers, resulting in improved mechanical properties. The different fiber sizes, in the proportions revealed here, influence how these fibers interact with each other and, consequently, affect the properties of the paper comprising them.

[0040] The base paper of the present invention has the following fiber length distribution, based on dry weight: i. 0 to 0.2 mm: about 9.90 to 12.20%; ii. 0.2 to 0.6 mm: about 18.30 to 21.90%; iii. 0.6 to 1.2 mm: about 63.10 to 66.70%; iv. 1.2 to 2.0 mm: approximately 3.90 to 6.70%; and v. 2.0 to 3.2 mm: approximately 0.10 to 0.40%.

[0041] Fiber lengths were measured according to ISO 16065-2 2014.

[0042] In one embodiment of the invention, the base paper comprises natural starch between the layers. The natural starch serves to bind the layers of the paper together.

[0043] In one embodiment of the invention, one or more of the base paper layers comprise additives selected from cationic starch, oxidized starch, and a sizing agent, preferably AKD sizing. In a preferred embodiment, the cationic starch is added to all three layers of the paper (inner, core, and outer). In a preferred embodiment, the oxidized starch is the surface starch and is applied in the size press, coating the inner and outer layers of the board. In a preferred embodiment, the sizing agent is added to all three layers of the paper (inner, core, and outer).

[0044] Cationic starch helps with adhesion between fibers, i.e. fiber-to-fiber bonding.

[0045] Oxidized starch, or surface starch, aids in water absorption and fiber-to-fiber bonding, preventing fiber detachment during the printing process. Furthermore, this starch helps ensure that the resin remains on the surface of the paper during coating application, reducing the amount of resin migrating into the base paper. Sheet bonding and fiber-to-fiber bonding are assessed using the Scott-bond test.

[0046] The sizing agent applied to the base paper of the present invention is used for Cobb properties; to prevent water absorption into the fibers. Preferably, the agent is a neutral and alkaline sizing agent based on AKD (alkyl ketene dimer).

[0047] In one embodiment of the invention, the base paper has a grammage of about 200 g / m 2 at about 300 g / m 2 , in which the outer layer and the inner layer have a weight of approximately 50 g / m 2each. The core layer weight is the difference between the total weight of the base paper and the sum of the weights of the outer and inner layers (sum equal to 100 g / m 2 ). Paper weight is measured according to ISO 536:2012 - Paper and board - Determination of Grammage.

[0048] The base paper of the present invention has: i. tensile strength L of about 10 kN / m to about 20 kN / m; ii. elongation L of about 1.3 mm to about 2.5 mm; iii. TEA (Tensile Energy Absorption) L of about 150 J / m 2 at about 300 J / m 2 and TEA index L of about 450 J / kg to about 1,350 J / kg; iv. tensile strength T of about 7 kN / m to about 12 kN / m; v. elongation T of about 4 mm to about 8 mm; and / or vi. TEA (Tensile Energy Absorption) T of about 280 J / m 2 at about 500 J / m 2and TEA T index of about 1,100 J / kg to about 2,200 J / kg; wherein the tensile strength L, elongation L, TEA L, TEA L index, tensile strength T, elongation T, TEA T and TEA T index are measured in accordance with ABNT - NBR ISO 1924-3:2006 - Determination of tensile properties - Part 3: Constant elongation rate method (100 mm / min).

[0049] The paper of the present invention also has excellent machinability, which can be defined as the production speed and quality in the forming machine of the container made with the paper of the invention, for example, a cup.

[0050] The base paper of the present invention has Scott Bond bond values ​​greater than 65 lb. ft / in. 2, measured based on TAPPI 569. Scott Bond correlates with internal delamination and the range of values ​​used in the present invention prevents problems from occurring during the polyethylene extrusion and / or resin application steps, as well as during the formation of the liquid container (cup).

[0051] In a preferred embodiment of the invention, the paper is cardboard.

[0052] The paper of the present invention may additionally comprise one or more barrier layers. The paper comprising barrier layers of the present invention has good sealing and barrier properties to liquids and grease. Furthermore, said paper has good production capacity at high speeds and does not present blocking problems.

[0053] In one embodiment of the invention, the base paper is coated with biodegradable barrier layers. This paper comprises: - a barrier layer of 4 to 6 g / m 2applied to the outer layer, wherein the barrier layer comprises a resin and optionally a release agent and / or an additive to increase the coefficient of friction; - a barrier layer of 3 to 5 g / m 2 applied to the inner layer, where the barrier layer comprises a resin; - a barrier layer of 4 to 6 g / m 2 applied to the inner layer, where the barrier layer comprises a resin, a release agent and an additive to increase the coefficient of friction.

[0054] In a preferred embodiment of the invention, the base paper coated with biodegradable barrier layers comprises: - a barrier layer of 4 to 6 g / m 2 applied to the outer layer, where the barrier layer comprises about 95% of the resin and optionally about 3% of the release agent and / or about 2% of the additive to increase the coefficient of friction; - a barrier layer of 3 to 5 g / m 2applied to the inner layer, where the barrier layer comprises 100% of the resin; - a barrier layer of 4 to 6 g / m 2 applied to the inner layer, where the barrier layer comprises approximately 94% of the resin, approximately 4% of the release agent and approximately 2% of the additive to increase the coefficient of friction.

[0055] The resin, release agent and additive to increase the coefficient of friction are biodegradable.

[0056] The resin is preferably a water-based styrene-acrylic resin and provides the paper with a barrier effect. The release agent is preferably a wax and is used to prevent blocking, preventing the sheets from sticking together on the reel or skid. Applying the wax layer makes the paper very smooth, so it is necessary to include an additive to increase the coefficient of friction (COF), which increases the paper's friction. This COF additive is a water-based styrene-acrylic additive.

[0057] Although both the resin and the additive are styrene acrylic, there is a difference between them related to the polymerization process, in which the glass transition temperature (T g ) of the additive is larger and generates microspheres.

[0058] The paper coated with the biodegradable barrier layers according to the present invention has high bonding properties, making it suitable for use in containers for liquids or food. In particular, this coated paper can be used for liquids and food up to approximately 95°C.

[0059] Furthermore, this coated paper has a repulpability above 90%, preferably around 96%, and is biodegradable, recyclable and compostable.

[0060] Containers made with the coated paper of the present invention are reusable and recyclable, made with raw materials from renewable sources and have coatings that guarantee sensory properties.

[0061] In another embodiment of the invention, the base paper is coated with polymer barrier layers on the inner and outer layers. This polymer-coated paper comprises: - a barrier layer of 12 to 16 g / m 2applied to the outer layer, where the barrier layer comprises Low Density Polyethylene (LDPE); and - a barrier layer of 16 to 20 g / m 2 applied to the inner layer, where the barrier layer comprises Low Density Polyethylene (LDPE).

[0062] Paper coated with LDPE on the outer and inner layers can be used to form containers for hot and cold liquids and foods.

[0063] In another alternative embodiment of the invention, the base paper is coated with a polymer barrier layer only on the inner layer. This polymer-coated paper comprises: - a barrier layer of 16 to 20 g / m 2 applied to the inner layer, where the barrier layer comprises Low Density Polyethylene (LDPE).

[0064] Paper coated with LDPE only on the inner layer can be used to form containers for liquids and hot foods.

[0065] The Low Density Polyethylene (LDPE) used in the polymer coated paper of the present invention is obtained by an extrusion process, in which the solid LDPE is melted and a film is formed, and the film is subsequently applied to the paper.

[0066] The polymer coated paper of the present invention can be used to form containers for liquids and foods up to about 95°C.

[0067] In one embodiment of the invention, the base paper comprising barrier layers is for forming containers for liquids, such as cups, or food, preferably for immediate consumption.

[0068] The paper comprising barrier layers of the present invention has high external barrier strength, good printability (flexographic, offset), low water absorption, and alcohol resistance of up to 15%. Furthermore, this paper is 100% recyclable.

[0069] Also described in the present invention is the use of the base paper comprising barrier layers of the invention for the production of containers for liquids, such as cups, or food, preferably for immediate consumption.

[0070] A container made from the paper of the present invention is disclosed herein. The container can be a cup, a container, a lunch box, a food box, or a jar. The container is for liquids or foods, such as coffee, juice, soda, beverages with an alcohol content of up to 15%, dry and fatty foods, popcorn, and ice cream. In a preferred embodiment, the container is for liquids or foods for immediate consumption.

[0071] The container of the present invention is suitable for contact with food, can be produced entirely from renewable raw materials, is sealable (in the ultrasonic or hot air process) and can be recycled and / or biodegraded, preferably it can be composted.

[0072] The container comprising the paper of the present invention is technically very versatile due to its rigidity, thickness, printability and high productivity. EXAMPLES

[0073] The examples presented in the present invention are non-exhaustive, serve only to illustrate the invention and should not be used as a basis for limiting it. Example 1

[0074] In this example, tests related to the morphology of the fibers comprised in the base paper of the present invention are described.

[0075] Eleven samples of base paper with a weight of 210 g / m were tested. 2 , 230 g / m 2 and 250 g / m 2 . The weights were measured in accordance with ISO 536:2012 - Paper and board - Determination of Grammage.

[0076] Table 1 lists the properties of weighted fiber length, fiber wall thickness, fibrillation, fines content, and number of fibers per gram. These fiber properties were measured on paper using fiber image analysis equipment based on ISO 16065-2 2014. Table 1

[0077] The weighted fiber length of 0.77 mm to 0.82 mm gives the paperboard excellent fiber interlacing, ensuring the ideal Scott bond for application, elasticity and surface uniformity to receive barrier application, polyethylene extrusion and high print quality.

[0078] The wall thickness of 4.61 pm to 5.68 pm gives rigidity to the cardboard paper, achieving good properties in lower weights and contributing to the resistance of the container made with said paper, for example, a cup.

[0079] Fibriling contributes to paper strength. The higher the fibrillation, the greater the fiber-to-fiber contact and the greater the paper's strength. A fibrillation level of 1.38% to 1.73% ensures the fiber-to-fiber bond in the paperboard to withstand the extrusion and folding processes. Furthermore, this level is combined with the internal sizing agent to promote liquid capillary control and low edge wicking.

[0080] The number of fibers per gram ranged from 15.18 to 18.9 million. The fiber density in short-grain paperboard provides adequate bulk for product compression during sealing, allowing for the necessary deformation for joining the layers during compression.

[0081] In addition to the above properties, the fiber length distribution of the base paper of the present invention was evaluated in samples of paper with a grammage of 210 g / m. 2 , 230 g / m 2 and 250 g / m 2. The distributions were measured based on dry weight and in accordance with ISO 16065-2 2014, and are shown in Table 2. The fibers tested have a width greater than or equal to 10 pm. Table 2

[0082] This distribution by fiber length allows the base paper of the present invention to have good mechanical properties, such as TEA and elongation.

[0083] Other properties related to the morphology of the fibers included in the paper of the present study are found in Table 3 and were also measured on the paper using fiber image analysis equipment, based on the ISO 16065-2 2014 Standard. Table 3 Example 2

[0084] In this example, tests related to the mechanical properties of the base paper of the present invention are described, that is, the paper comprising an outer layer, core layer and inner layer, without barrier layers.

[0085] The properties evaluated in the present studies are Tensile Strength L, Elongation L, TEA L, TEA index, Tensile Strength T, Elongation T, TEA T, and TEA index. Ten measurements of these properties were performed for each sample. Table 4 shows the averages of the ten measurements performed for each sample, and Figures 5 to 11 represent graphs of the properties of the tested samples. These properties were measured in accordance with ABNT - NBR ISO 1924-3:2006.

[0086] With this study, it can be observed that the paper of the present invention has good mechanical properties, so that containers for liquids or food made with this paper will have good resistance. Table 4

[0087] This example describes Biodegradability, Compostability and Ecotoxicity Tests of the paper coated with biodegradable layers of the present invention. The tested sample comprises: - an outer layer comprising bleached short cellulose fiber; - a flute layer comprising bleached short fiber cellulose and bleached short fiber chemithermomechanical pulp, based on the total dry weight of the flute layer in the paper; - an inner layer comprising bleached short cellulose fiber; - a barrier layer applied to the outer layer, where the barrier layer comprises 95% resin, 3% release agent and 2% additive to increase the coefficient of friction; - a barrier layer applied to the inner layer, wherein the barrier layer comprises 100% of the resin; and - a barrier layer applied to the inner layer, where the barrier layer comprises 94% resin, 4% release agent and 2% additive to increase the coefficient of friction.

[0088] The sample consists of paper coated in white polymeric material, weighing approximately 2.601 kg. 3.1. Biodegradability Test

[0089] The present test aimed to determine Biodegradability.

[0090] All components of the coating layers (resin, release agent, and additive to increase the coefficient of friction) are biodegradable. It should be noted that the biodegradability test was performed on the final composition, which comprises the base paper and the coating layers.

[0091] The sample was previously reduced to approximate dimensions of 2 cm x 2 cm for the test. Table 5 presents the data regarding the masses of sample, organic compound, cellulose (reference) used and their description, in each incubation reactor. The test was performed in triplicate for each condition evaluated (organic compound, cellulose and sample).

[0092] The initial parameters of the biodegradability test are presented in Table 5. Table 5 Incubation reactors 1, 2 and 3 = organic compound Incubation reactors 4, 5 and 6 = cellulose (reference) Incubation reactors 10, 11 and 12 = sample

[0093] The pH and humidity values ​​monitored during the biodegradability test can be seen in Figures 12 and 13, respectively.

[0094] From the data obtained on carbon dioxide (CO2) released in each incubation reactor, a graph was created that relates the percentage of biodegradability of the paper sample with barrier layers of the invention and cellulose (reference), during the test period, as shown in Figure 14.

[0095] The methods used to determine biodegradability were in accordance with DIN EN 13432:2000, DIN EN 13432:2000 Corrigendum 2:2007, ISO 14855-1:2012 and ABNT NBR 15448-2:2008. Biodegradability was determined through a test that simulates an intense aerobic composting process in the laboratory, under controlled conditions. The percentage of biodegradability was determined by the conversion of the organic carbon of the sample into carbon dioxide (CO2) released during the test period.

[0096] As can be seen in Figure 14, the cellulose (reference), under the test conditions, presented a biodegradability percentage of 100% of its mass after the 67-day period. The paper sample with barrier layers of the invention presented a biodegradability percentage of 100% of its organic constituents after the approximately 130-day test period, under controlled aerobic composting conditions according to the methodology of ISO 14855-1:2012.

[0097] According to ABNT NBR 15448-2 standard, the sample must present a biodegradability percentage of at least 90% of its organic constituents, after the end of 180 days of testing, for it to be considered a biodegradable material.

[0098] Thus, according to ABNT NBR 15448-2:2008 standard, the paper sample with barrier layers of the invention analyzed met the biodegradability requirements under controlled aerobic composting conditions. 3.2. Compostability Test

[0099] The present test aimed to determine disintegration through composting.

[0100] Table 6 presents the data regarding the sample masses used, organic compound (reference), initial moisture, pH and temperature parameters. The test was performed in duplicate for each condition evaluated (organic compound and sample). Table 6

[0101] After the end of the composting process (12 weeks), the fertilizer formed was sieved using a sieve with a 10 mm mesh opening and then a sieve with a 2 mm opening, collecting all the pieces of the test sample that did not pass through the 2 mm sieve.

[0102] In Figure 15, the images of the organic compound formed after the test can be observed, the remaining fragments of the test material retained in the sieve with an opening of 2 mm in diameter. In particular, Figure 15 (a) refers to the organic compound after sieving (2 mm sieve) and Figure 15 (b) refers to the sample remaining after sieving (2 mm sieve).

[0103] The methods used to determine disintegration through composting were in accordance with DIN EN 14045:2003 and ABNT NBR 15448-2:2008. The test was carried out under aerobic composting conditions on a pilot scale. The degree of disintegration was obtained after 12 weeks of testing by determining the total dry solids mass of the remaining sample particles that did not pass through the 2 mm sieve.

[0104] Table 7 presents the results obtained after the end of the disintegration test through composting. Table 7

[0105] The values ​​presented in Table 7 refer to the averages of duplicate samples. As can be seen in Table 7, the amount of sample mass remaining after the Disintegration through Composting test after sieving using the 2 mm sieve was 5.10 g.

[0106] According to ABNT NBR 15448-2:2008 standard, the fraction retained after sieving using a 2 mm mesh opening must be less than 10% (requirement to meet the Disintegration through Composting criterion). Therefore, the sample must present a degree of disintegration greater than 90%.

[0107] The analyzed sample showed 99.67% disintegration of its organic constituents after the test period under aerobic composting conditions on a pilot scale according to the methodology of DIN EM 14045:2003 and ABNT NBR 15448-2:2008 standards.

[0108] Thus, according to ABNT NBR 15448-2:2008, the analyzed sample met the requirements for Disintegration through Aerobic Composting on a pilot scale. 3.3. Ecotoxicity Test

[0109] The present test aimed to evaluate ecotoxicity.

[0110] To evaluate the effects of the organic compound used in the composting disintegration test on the emergence and initial growth of higher plant seeds after exposure to the composting test, an ecotoxicity test was conducted. According to the standard, plant seeds of each species must be selected for the ecotoxicity test.

[0111] The ecotoxicity assessment of the Biodegradation products was based on OECD TEST No. 208 - Guidelines for the Testing of Chemicals, Section 2, Test No. 208: Terrestrial Plant Test: Seedling Emergence and Seedling Growth Test, 2006. The test was carried out by observing the emergence capacity of selected plants, as well as visible phytotoxic effects.

[0112] After 21 days of testing, the emergence capacity of plants in the soil composted with the sample was observed, compared with the controls (non-composted soil), indicating that its composting does not generate negative germination effects.

[0113] According to OECD 208, compound fertilizer meets the criteria for ecotoxicity when emergence (germination) of at least 70% of the species occurs, the plants do not present phytotoxic effects (chlorosis, necrosis, wilting of leaves and trunk deformations) and exhibit normal variation in growth and morphology for all germinated species.

[0114] According to OECD 208, the sample analyzed met the requirements for determining the ecotoxicity of biodegradation products. The plants showed no phytotoxic effects and exhibited normal growth and morphology for germinated species.

Claims

CLAIMS 1. Paper, characterized by the fact that it comprises: (a) an outer layer comprising bleached short cellulose fibre; (b) a fluting layer comprising about 70% to about 90% by weight of bleached hardwood pulp and about 10% to about 30% by weight of bleached hardwood chemithermomechanical pulp, based on the total dry weight of the fluting layer in the paper; and (c) an inner layer comprising bleached short cellulose fibre.

2. Paper according to claim 1, characterized in that it presents the following distribution by fiber length, based on dry weight: i) 0 to 0.2 mm: 9.90 to 12.20 %; ii) 0.2 to 0.6 mm: 18.30 to 21.90 %; iii) 0.6 to 1.2 mm: 63.10 to 66.70 %; iv) 1.2 to 2.0 mm: 3.90 to 6.70 %; and v) 2.0 to 3.2 mm: 0.10 to 0.40 %, in which the fiber lengths were measured in accordance with ISO 16065-2:2014.

3. Paper according to claim 1 or 2, characterized in that it comprises natural starch between the layers.

4. Paper according to any one of claims 1 to 3, characterized in that one or more of the layers comprises additives selected from cationic starch, oxidized starch and a binding agent.

5. Paper according to any one of claims 1 to 4, characterized in that the paper has a grammage of approximately 200 g / m 2 at about 300 g / m 2 , in which the outer layer and the inner layer have a weight of around 50 g / m 2 each, where the grammage is measured according to ISO 536:2012.

6. Paper according to any one of claims 1 to 5, characterized in that it has: i) tensile strength L of about 10 kN / m to about 20 kN / m; ii) elongation L of about 1.3 mm to about 2.5 mm; iii) TEA L of about 150 J / m 2 at about 300 J / m2 ; iv) tensile strength T of about 7 kN / m to about 12 kN / m; v) elongation T of about 4 mm to about 8 mm; and / or vi) TEA T of about 280 J / m 2 at about 500 J / m 2 ; where the tensile strength L, elongation L, TEA L, tensile strength T, elongation T and TEA T are measured according to ABNT - NBR ISO 1924-3:2006.

7. Paper according to any one of claims 1 to 6, characterized in that the paper is cardboard.

8. Paper according to any one of claims 1 to 7, characterized in that it additionally comprises one or more barrier layers.

9. Paper according to claim 8, characterized in that it comprises: - a barrier layer of 4 to 6 g / m 2 applied to the outer layer, wherein the barrier layer comprises a resin and optionally a release agent and / or an additive to increase the coefficient of friction; - a barrier layer of 3 to 5 g / m 2 applied to the inner layer, where the barrier layer comprises a resin; - a barrier layer of 4 to 6 g / m 2 applied to the inner layer, where the barrier layer comprises a resin, a release agent and an additive to increase the coefficient of friction.

10. Paper according to claim 8, characterized in that it comprises: - optionally a barrier layer of 12 to 16 g / m 2 applied to the outer layer, wherein the barrier layer comprises LDPE polyethylene; and - a barrier layer of 16 to 20 g / m 2 applied to the inner layer, where the barrier layer comprises LDPE polyethylene.

11. Paper according to any one of claims 1 to 10, characterized in that it is for forming containers for liquids or foods.

12. Use of the paper defined in any one of claims 1 to 10, characterized in that it is for the production of containers for liquids or food.

13. Container, characterized by the fact that it is obtained from the paper defined in any one of claims 8 to 10.

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