Paper intended to form U-shaped straw

Abstract

The present invention relates to a drinking U-shaped straw, and more particularly, to a paper for manufacturing a drinking U-shaped straw, which is environmentally friendly, biodegradable, and capable of forming the shape of a curved straw, having an accordion-like structure at the bend. The paper has high water resistance as well as high tensile properties compatible with intended use. In particular, the paper for forming a U-shaped straw comprises: 10 to 50 dry weight% of a first fiber having a length of 1.4 mm to 2.5 mm; 40 to 80 dry weight% of second fibers having a length of 0.3 mm to 0.8 mm; and 1 to 6 dry weight% of a sizing agent.

Description

[0001] This application is a divisional application of the invention patent application with application number 202180011285.7, application date February 1, 2021, and invention name “Paper intended to form U-shaped straws”. Technical Field

[0002] The present invention relates to a U-shaped drinking straw, and more particularly to a novel paper for manufacturing the U-shaped drinking straw. The paper is environmentally friendly and biodegradable, and can be formed into a curved straw shape with an accordion-like structure at the bend. The paper has high water resistance and high strength and elongation properties compatible with the intended use. Background Art

[0003] For reasons of hygiene and convenience, straws are widely used when drinking beverages, such as soda. Indeed, if the liquid is in a can, it can be helpful to avoid direct contact between the mouth and the can for hygiene reasons. Furthermore, using a straw for soda has been shown to limit the contact surface between the soda and the teeth, and to prevent the formation of dental caries due to the sugars contained in soda.

[0004] Traditional drinking straws are made of plastic and are intended for single use. This plastic material is too light and does not contain enough raw materials to make it environmentally and economically viable. Currently, the best way to extract value from these straws is to throw them into conventional garbage to recover the heat energy when incinerated. The problem is that incineration is extremely expensive. As a result, large quantities of lightweight plastic are stored in controlled landfills, especially in wealthier countries. Moreover, such plastic straws are often discarded by users in nature, becoming a source of pollution in rivers, oceans, forests, etc., and can also be harmful to aquatic or terrestrial animals and plants.

[0005] Furthermore, as some countries are seeking to remove as much plastic as possible from everyday items, such as plastic straws, it is also necessary to find a material that can replace plastic to make straws.

[0006] There is also a need to develop a straw material that is environmentally friendly and further has a relatively inexpensive disposal method and exhibits physical and mechanical properties that are compatible with use in wet conditions, particularly with respect to the integrity of the material over a predetermined period of time.

[0007] To address this problem, drinking straws made of paper have been developed.

[0008] Paper straws should have sufficient mechanical resistance to be used in liquids, i.e. have the ability to absorb water without being degraded.

[0009] For example, US2018235390(A1) discloses a straight straw formed from a cardboard sheet made of rapidly renewable resources and being recyclable, biodegradable, and compostable. The cardboard sheet is made of bamboo, bagasse, reed, or any combination thereof or a single material.

[0010] CN109463964(A) discloses a paper straight drinking straw, which comprises a first paper layer, a wax layer or a wax mixture layer covering the first paper layer, and a second paper layer covering the wax layer or the wax mixture layer.

[0011] DE 202018105665 U1 discloses an environmentally friendly and sustainable paper straw. However, in this document, food-grade laminates or edible wax are used to impart liquid repellency to the straw. These additional components increase the final price of the straw and the number of manufacturing steps.

[0012] US2019 / 0249369 A1 discloses a straw for drinking beverages, comprising a waterproof paper tube having an inner surface; and a composition layer disposed on the inner surface. The composition includes a plant-derived wax to make the cellulose-based material waterproof.

[0013] Most of the time, water resistance of paper requires the application of additional layers, especially layers made of wax, which increases the production costs. Water resistance in the sense of the present invention refers to the ability of paper to absorb water. This parameter is usually measured by the Cobb test.

[0014] These additional coatings disclosed in the prior art literature have some disadvantages.

[0015] Firstly, they do not allow the different layers of the straw to adhere adequately to one another due to incompatibility with the adhesive / glue.

[0016] Secondly, printing on wax is impossible. Therefore, one option is to print directly on the paper without applying a wax layer. The problem is that the straw's waterproof properties are reduced. A second option is to print directly on the paper without applying a wax layer, and then apply another layer on top of the printed layer to achieve some satisfactory waterproof properties. This second option is obviously expensive.

[0017] Today, as indicated in the prior art literature, there are many paper-based straight straws. However, there is a need to develop paper-based U-shaped straws, that is, straws with an accordion-like pivot for the convenience of the end user. The mechanical resistance of a U-shaped drinking straw is even more difficult to achieve, especially along the accordion area of ​​the straw, which combines flexibility and contact with the liquid. In addition, the formation of this pivot area requires the paper to have specific physical and mechanical properties, in particular, elongation, to prevent the paper from tearing during the formation of the U-shaped part of the straw.

[0018] Thus, various aspects of the present invention are directed to at least one paper for manufacturing a U-shaped drinking straw that has mechanical properties that enable the formation of an accordion region and is easily processed in conventional equipment. Another aspect is directed to a straw that is waterproof and compatible with use as a U-shaped drinking straw without requiring specialized coatings, such as wax. Another aspect is directed to a directly printable paper. Another aspect is directed to a biodegradable and environmentally friendly paper.

[0019] To at least partially address the problems outlined above, the applicant has developed a composition that enables specific tensile strength and cobb strength values ​​to be achieved to meet the requirements for using paper in U-shaped straws and to comply with the process requirements for forming the accordion region of the U-shaped straw. Summary of the Invention

[0020] In one aspect of the present invention, a paper for forming a U-shaped straw is disclosed. The paper is characterized in that it comprises:

[0021] 10 to 50% by dry weight of first fibers having a length of 1.4 mm to 2.5 mm;

[0022] 40 to 80% by dry weight of second fibers having a length of 0.3 mm to 0.8 mm; and

[0023] 1 to 6% by dry weight of a sizing agent;

[0024] The paper has:

[0025] 4 to 8% transverse elongation.

[0026] The formulation disclosed above provides a paper having the mechanical and physical properties required for use in straws. More specifically, the formulation makes it possible to obtain a paper having a sufficiently high transverse elongation to enable the accordion portion of a U-shaped straw to be formed without tearing the paper during the formation of the accordion portion, and also to ensure its integrity when exposed to liquids. In addition, the formulation further enables the paper to have a high resistance to moisture (also known as water resistance) to maintain structural integrity when in contact with liquids and to function as a straw. Using this formulation, a paper having sufficient tensile strength is obtained for use as a straw. As will be explained in other paragraphs, one or more layers of paper can be used to make straws.

[0027] The paper intended to form a U-shaped straw may further present one or more of the following technical features, alone or in combination.

[0028] In one embodiment, the paper of the present invention may comprise a Cobb water resistance of 15 to 34 gsm. Such Cobb water resistance is measured according to ISO 535.

[0029] According to a particular embodiment, the paper may comprise 0.5 to 1.5% by dry weight of at least one wet strength agent.In some embodiments, the paper may comprise no wet strength agent.

[0030] The paper has a machine direction and a cross machine direction. The paper may further have a machine direction tensile strength of 3 to 9 kN / m. The machine direction and cross machine direction tensile strength are measured according to ISO 1924.

[0031] The paper can have a transverse tensile strength of 0.8 to 5 kN / m. In certain embodiments, the transverse tensile strength can be from 0.8 to less than 1.2 kN / m. This lower tensile strength range is typically seen in lighter and thinner papers according to the present invention, but still provides sufficient tensile strength for use in U-shaped straws. In other embodiments, the transverse tensile strength can be from 1.2 to 5 kN / m. Higher tensile strength is helpful during high-speed processing and converting the paper into the U-shaped straw shape.

[0032] The paper may have a transverse elongation of 4 to 8%, preferably 5 to 7%, measured according to ISO 1924-5. Such a transverse elongation enables the paper to be squeezed without breaking, thereby enabling the U-shaped portion of the U-shaped straw to be formed.

[0033] The paper may have a machine direction elongation measured according to ISO 1924-5 of 2 to 4%, preferably 2.4 to 3.5%.

[0034] In a particular embodiment, the paper may contain broke in an amount ranging from 0.5 to 20% by dry weight. In some embodiments, the paper may not contain any broke.

[0035] The paper may further comprise at least one filler. The filler is advantageously chosen from talc or calcium carbonate.

[0036] According to a particular embodiment, the paper of the invention may further contain starch, said starch being present in the paper in an amount of at most 1 % by dry weight.

[0037] The paper comprises 1 to 6% by dry weight of sizing agent.In one embodiment, the paper according to the invention may also preferably contain a wax based on alkyl ketene dimer (AKD) as sizing agent.

[0038] According to a particular embodiment, the paper of the invention may further contain sodium carbonate, present in the sizing agent in an amount of up to 2% by dry weight. The inventors have surprisingly observed that the presence of sodium carbonate prevents the deposition of AKD in the tanks where the preparation takes place and allows AKD to be catalyzed in the drying part of the plant.

[0039] Optionally, the paper may comprise a wet strength agent. In one embodiment, the wet strength agent may comprise polyamine epichlorohydrin (PAE), or formaldehyde is preferred when providing a wet strength agent.

[0040] In a particular embodiment, the paper may include at least one of the following features:

[0041] The length of the first fiber is 1.6 mm to 1.8 mm,

[0042] The length of the second fiber is 0.5 mm to 0.7 mm.

[0043] The paper may have a thickness of 40 μm to 200 μm. In one embodiment, the paper may have a thickness of 65 μm to 190 μm.

[0044] In order to improve the strength of paper, the paper may have a machine direction tear strength of 45 g to 140 g and / or a cross machine direction tear strength of 45 g to 140 g, measured according to ASTM D 412 method.

[0045] In one embodiment, the paper may include at least one of the two following characteristics:

[0046] Wet burst strength of 55KPa to 200KPa measured according to ISO3689,

[0047] • Gramweight of 30-140 gsm measured according to ISO 536.

[0048] In another embodiment, the paper may include at least one of two of the following characteristics:

[0049] Wet burst strength of 55KPa to 200KPa measured according to ISO3689,

[0050] • Gramweight of 60-140 gsm measured according to ISO 536.

[0051] A further aspect of the invention relates to a U-shaped drinking straw made from at least one layer of paper as defined above.

[0052] Advantageously, the use of the paper described herein for forming a U-shaped straw prevents tearing of the paper during the formation of the accordion portion that forms the pivoting portion of the straw. Furthermore, the paper having the characteristics defined above allows the accordion portion of the U-shaped straw to also have mechanical and physical properties that prevent the paper from collapsing under wet conditions.

[0053] In a first embodiment, the U-shaped straw is made from three layers of said paper. These layers form a laminate and are bonded together by a food-compatible glue.

[0054] The inventors have found that particularly satisfactory results are obtained when the U-shaped straw is made from an outer layer having a grammage of 60 gsm, an inner layer having a grammage of 60 gsm and an intermediate layer having a grammage of 120 gsm, the intermediate layer being arranged between the inner and outer layers.

[0055] In this embodiment, the paper forming the outer layer has a porosity of 360 to 800 ml / min and / or the paper forming the inner layer has a porosity of 360 to 800 ml / min, measured according to ISO 5636-3.

[0056] In a second embodiment, a U-shaped straw is made from two layers of paper as described herein (an inner layer and an outer layer, respectively). These layers form a laminate and are bonded together by a food-compatible glue.

[0057] In this embodiment, particularly satisfactory results were obtained when the U-shaped straw was made from an outer layer having a grammage of 80 gsm and an inner layer having a grammage of 140 gsm. Advantageously, the outer layer has a porosity of 360 to 800 ml / min, measured according to ISO 5636-3.

[0058] Other advantages and characteristics of the invention will become clearer in the following description, which is given by way of illustration and not by way of limitation.

[0059] In the following description, reference is made to a first fiber and a second fiber. The terms "first" and "second" are used solely to distinguish between two elements that are close but not identical. These terms are not intended to define precedence or spatial or temporal placement between these elements. Furthermore, these terms may be interchanged without detracting from the following description.

[0060] In addition, in the following description, it refers to an "inner" layer and an "outer" layer. These terms are general terms used to better identify the position of these layers in the U-shaped straw structure and are not intended to limit the disclosure of the present invention. In addition, these terms can be interchanged without affecting the following disclosure. DETAILED DESCRIPTION

[0061] Aspects of the present invention relate to a U-shaped straw made from at least one layer of the paper. The paper comprises at least 10-50% by dry weight of first fibers, 40-80% by dry weight of second fibers, and 1-6% by dry weight of a sizing agent. Unless otherwise stated, the weight percentages or dry weight percentages disclosed herein are relative to the total composition of the paper (the total composition of the paper is 100% by dry weight). In addition, in a specific embodiment, the paper has a thickness of 40 μm to 190 μm and a grammage of 30 gsm to 140 gsm, preferably a thickness of 65 μm to 190 μm and a grammage of 60 gsm to 140 gsm. Optionally, the paper may contain 0.5 to 1.5% by dry weight of a wet strength agent.

[0062] In one embodiment, the composition for paper is such that the paper has a transverse tensile strength of 0.8 to 5 KN / m, preferably 1.2 to 5 KN / m, and / or a transverse elongation of 4 to 8%, more preferably an elongation of 5 to 7%. Such transverse tensile strength and transverse elongation enable the paper to have sufficient strength to form the accordion portion of a U-shaped straw. That is, the paper will resist the compression applied to form the accordion portion without tearing, and the paper will further have sufficient strength to prevent any collapse of the U-shaped straw formed with the paper. In addition, the composition of such paper enables it to have a Cobb water resistance of 15 to 34 gsm on one side (e.g., the reverse side) and a Cobb water resistance of 15 to 34 gsm on the other side (e.g., the front side), the two Cobb water resistance values ​​being the same or different. Cobb water resistance is measured according to ISO 535. Such Cobb water resistance enables the paper to be used in U-shaped straws because such a value will be able to ensure the integrity of the paper under humid conditions during the general use of such straws. In practice, a typical straw is used for about 20 minutes. The paper used to form the U-shaped straw also needs to have a sufficiently high water resistance to prevent any dissolution, collapse, or other degradation of the paper within at least 30 minutes of contact with water. Such a Cobb water resistance value enables the paper to meet these requirements.

[0063] Furthermore, paper made from this composition can have a machine-machine-direction elongation of 2 to 4%, more preferably 2.4 to 3.5%. This elongation property enables the paper to prevent any tearing of the accordion portion, which forms the pivoting portion of the straw, during use when formed into a U-shaped straw. Furthermore, this elongation property helps prevent the paper from tearing during the formation of the accordion portion of the U-shaped straw. Furthermore, the paper can have a machine-machine-direction tensile strength of 3 to 9 kN / m. The tensile strength in the machine-machine-direction and cross-machine-direction directions is measured according to ISO 1924. The paper then has a machine-machine-direction tear strength of 45 to 140 g and a cross-machine-direction tear strength of 45 to 140 g. These machine-machine-direction and cross-machine-direction tear strengths also help prevent the paper from tearing during the formation of the accordion portion of the U-shaped straw, as well as during the pivoting of the straw portion and during use of the U-shaped straw.

[0064] Furthermore, the paper can be refined to a Schopper with a SR of 45 to 50°. The paper can further have a wet burst strength of 55 kPa to 200 kPa. Such wet burst strength values ​​provide the paper with water resistance compatible with use in forming U-shaped straws intended for exposure to water. It also prevents the U-shaped straws from collapsing under wet conditions.

[0065] The length of the first fibers is 1.4 mm to 2.5 mm, preferably 1.6 mm to 1.8 mm. The first fibers can be selected, for example, from softwood fibers, such as Northern Bleached Softwood Kraft (NBSK) or Southern Bleached Softwood Kraft. Other types of softwood pulp or even unbleached softwood pulp can also be used.

[0066] Furthermore, the length of the second fibers is from 0.3 mm to 0.8 mm, more preferably from 0.5 mm to 0.7 mm. These second fibers can be selected, for example, from hardwood fibers, such as eucalyptus pulp, or northern bleached hardwood kraft pulp (NBHK) or southern bleached hardwood kraft pulp. Other types of hardwood pulp or even unbleached hardwood pulp can also be used.

[0067] In some embodiments, the paper may contain more than two types of fibers, such as additional third and / or fourth fibers, etc. The additional fibers may include any suitable type of fiber that is a different material than the first and second types of fibers. In certain embodiments, the additional fibers may include PCW (post-consumer waste) pulp, and / or any other form of recycled pulp that may be food grade, or may include non-wood fibers.

[0068] The sizing agent may be an alkyl ketene dimer (AKD), alkenyl succinic anhydride (ASA), and / or a rosin-based sizing agent. Alternatively, the sizing agent may include SMA (styrene maleic anhydride), SAE (styrene acrylic emulsion), SAA (styrene acrylic acid), EAA (ethylene acrylic acid), polyester, polyethylene, combinations thereof, or any other suitable material. In certain embodiments, the sizing agent may be applied to the surface of the paper.

[0069] The sizing agent enables one to achieve a Cobb water resistance compatible with the requirements for forming U-shaped straws using such paper. According to a particular embodiment, a small amount of sodium carbonate, typically up to 2% by dry weight, may be added to the sizing agent. The addition of sodium carbonate enables catalysis of AKD in the dryer section of the paper machine during the paper forming process. Thus, the use of sodium carbonate can increase the production speed of paper. Advantageously, the inclusion of a sizing agent in the paper composition allows the wax layer applied in the prior art to be eliminated, while also enabling the printing of such paper.

[0070] Furthermore, wet strength agents can be selected from polyamine epichlorohydrin (PAE), glyoxylated resins (GPAM – glyoxylated polyacrylamide), or formaldehyde-based resins. Formaldehyde-based resins can be selected from urea-formaldehyde-based resins and melamine-formaldehyde-based resins. Such wet strength agents contribute to the resistance of paper to wet conditions.

[0071] According to one embodiment, the paper may further contain 0.5 to 20% by dry weight of broke. Broken corresponds to the recycled portion of paper obtained at the beginning or end of paper processing. Those portions of the produced paper are usually wrinkled and may not be used. Such broken paper can also be considered as recycled paper from the paper manufacturing process. Using such broken paper can also reduce the production costs of such paper.

[0072] Furthermore, optionally or additionally, the paper may contain at least one filler, for example, selected from talc or calcium carbonate. Such fillers may also influence the whiteness and opacity of the paper and may further reduce production costs. The at least one filler may be present in the paper composition in an amount of up to 7% by dry weight.

[0073] Optionally, the paper may contain up to 1% starch by dry weight. Starch is used in the composition of paper for wet-end purposes. More specifically, starch improves the strength of the paper during wet-end processing and also improves the runnability of the manufacturing process.

[0074] The paper can be made by known methods. In one embodiment, at least the first fiber and the second fiber are introduced into a pulp pool, and water is added to suspend those fibers. Optionally, in the case where sizing agents, wet strength agents, fillers and / or starch are present in a large amount of paper, these substances can be added to the pulp pool. The suspension obtained is then usually refined and then distributed on a forming wire to form a layer. During the conveying of the dispersion containing at least the first fiber and the second fiber, some water is removed by drainage. The obtained layer then passes through a press section, that is, is pressed between two cylinders to enable further removal of water from the layer. The press section may comprise more than one workstation consisting of two cylinders. In this case, the pressure applied to the layer is increased at each workstation to dry the layer by pressing it. At the end of the press section, a paper layer is obtained.

[0075] The manufacturing process may also include a size press step. Once the paper layer is obtained, this size press step is performed. In fact, sizing agents can be added to the paper during this step through the size press. In addition, the manufacturing process may also include a calendering step after the size press step. This calendering step can reduce the thickness or porosity of the paper or increase the smoothness of the paper. Optionally or additionally, the manufacturing process may further include a coating step. This coating step may include depositing pigments or fillers to further increase the smoothness of the paper, thereby improving, for example, the printing properties of the paper.

[0076] In the following, some specific recipes are given, one relating to a paper having a grammage of 60 gsm, another relating to a paper having a grammage of 120 gsm, a third relating to a paper having a grammage of 80 gsm, a fourth relating to a paper having a grammage of 80 gsm made without any wet strength agent, and a fifth relating to a paper having a grammage of 34 gsm.

[0077] First formulation: Preparation of paper with a grammage of 60 gsm

[0078] According to this first formulation, paper is made from the components listed in the following table:

[0079]

[0080] The technical characteristics of the paper obtained with this first formulation are as follows:

[0081] characteristic unit value thickness μm 69 Paper machine longitudinal elongation ％ 2.8 Transverse elongation ％ 6.2 Machine longitudinal tensile strength KN / m 4.2 Transverse tensile strength KN / m 2.7 Wet burst strength KPa 55 Cobb water resistance on the reverse side gsm 17 Front Cobb water resistance gsm 17 Paper machine longitudinal tearing strength g 58 Transverse tearing strength g 60

[0082] Second formulation: Preparation of paper with a grammage of 120 gsm According to this second formulation, paper was made from the components listed in the following table:

[0083]

[0084] The technical characteristics of the paper obtained with this second formulation are as follows:

[0085]

[0086]

[0087] Third formulation: Preparation of paper with a grammage of 80 gsm

[0088] According to this third formulation, paper is made from the components listed in the following table:

[0089]

[0090] The technical characteristics of the paper obtained with this third formulation are as follows:

[0091] characteristic unit value thickness μm 80 Paper machine longitudinal elongation ％ 2.1 Transverse elongation ％ 6.5 Machine longitudinal tensile strength KN / m 5.8 Transverse tensile strength KN / m 3.7 Wet burst strength KPa 60 Cobb water resistance on the reverse side gsm 20 Front Cobb water resistance gsm 20 Paper machine longitudinal tearing strength g 65 Transverse tearing strength g 80

[0092] Fourth recipe: Preparation of paper with a grammage of 80 gsm

[0093] According to this fourth formulation, paper was prepared without any wet strength agent in the composition. More specifically, the paper was made from the components listed in the following table:

[0094]

[0095] The technical characteristics of the paper obtained with this fourth formulation are as follows:

[0096] characteristic unit value thickness μm 80 Paper machine longitudinal elongation ％ 2.1 Transverse elongation ％ 6.5 Machine longitudinal tensile strength KN / m 5.8 Transverse tensile strength KN / m 3.7 Cobb water resistance on the reverse side gsm 20 Front Cobb water resistance gsm 20 Paper machine longitudinal tearing strength g 65 Transverse tearing strength g 80

[0097] Fifth formulation: preparing paper with a grammage of 34 gsm.

[0098] According to this fifth formulation, paper is made from the components listed in the following table:

[0099]

[0100] This paper can also be made with up to 20% broke by weight. As mentioned above, this lightweight paper also contains some precipitated calcium carbonate (PCC), which can be added to the paper to increase opacity and / or add color or hue to the outer layer of the paper, which may be useful when forming U-shaped straws from the paper. When provided, the amount of PCC used in the paper is typically about 1-2% by weight.

[0101] The technical characteristics of the paper obtained with this fifth formulation are as follows:

[0102] characteristic unit value thickness μm 44 Paper machine longitudinal elongation ％ 2.0％ Transverse elongation ％ 4.2％ Machine longitudinal tensile strength KN / m 3.6 Transverse tensile strength KN / m 1.2 Wet burst strength KPa 37 Cobb water resistance on the reverse side gsm 14 Front Cobb water resistance gsm 15 Paper machine longitudinal tearing strength g 28.1 Transverse tearing strength g 34.3

[0103] In the following, some specific U-shaped straws made of at least one layer of the paper described above are described.

[0104] The first U-shaped straw implementation: made of two layers of paper

[0105] The first U-shaped straw is made of two layers of paper as disclosed above. The two layers of paper are glued with a food-compatible glue (such as the one manufactured and sold by Henkel). CW21058 glue) together. More specifically, the U-shaped straw is made of an inner layer and an outer layer. The inner layer is intended to come into contact with the beverage during use of the U-shaped straw, and the outer layer is intended to come into contact with the mouth of the user of the U-shaped straw.

[0106] The inner layer is made of the 140 gsm paper disclosed above. The paper forming this inner layer is not calendered, as it does not need to have a defined smoothness, as only the liquid (i.e., the beverage) is intended to come into contact with the paper. Therefore, this U-shaped straw is particularly designed for still beverages, such as juice.

[0107] On the other hand, the outer layer has a grammage of approximately 80 gsm. The outer layer is calendered to have a predetermined smoothness, more specifically, to prevent damage to the mouth of a user of the U-shaped straw. More specifically, the porosity of the paper forming the outer layer is 360 ml / min to 800 ml / min. This porosity of the paper forming the outer layer ensures that the outer layer has the desired smoothness to prevent any damage to the user's mouth during use of the U-shaped straw disclosed in the first embodiment.

[0108] Second U-shaped straw implementation: made of three layers of paper

[0109] In another embodiment, a U-shaped straw is made of three layers of the paper disclosed above, the layers being bonded together with a food-compatible glue, which may be the same glue used in the first embodiment of the U-shaped straw. More specifically, this U-shaped straw is made of an inner layer intended to come into contact with the beverage during use of the U-shaped straw, an outer layer intended to come into contact with the user's mouth during use of the U-shaped straw, and an intermediate layer sandwiched between the inner and outer layers.

[0110] The inner layer may have a grammage of approximately 60 gsm. The inner layer may or may not be calendered. More specifically, the inner layer may be calendered to provide the layer with a predetermined smoothness, more specifically, a porosity of 360 ml / min to 800 ml / min. If the U-shaped straw is intended for use with sparkling beverages, the inner layer is preferably calendered to prevent foaming. However, if the U-shaped straw is intended for use with non-sparkling beverages, calendering the inner layer is not necessary.

[0111] In addition, the outer layer may also have a grammage of about 60 gsm. The outer layer is calendered to have a porosity of 360 ml / min to 800 ml / min in order to have smoothness to prevent any damage to the user's mouth as disclosed in the first U-shaped straw embodiment.

[0112] The intermediate layer may have a grammage of 120 gsm. This intermediate layer is not calendered, as there is no need to calender this intermediate layer. In fact, this intermediate layer is only intended to provide the U-shaped straw with sufficient rigidity to prevent it from collapsing, for example when it is intended to be used to punch a hole in the lid of a closed beverage carton.

[0113] Thus, a paper is obtained that is intended to form a U-shaped straw having properties that enable the formation of an accordion region and that is easy to process in conventional equipment, as well as having waterproof properties compatible with use in drinking straws, without the need for special coatings such as wax layers, and the paper using the paper composition disclosed above can be directly printable and can also be biodegradable and environmentally friendly. In fact, the composition disclosed above enables the paper to have compatible mechanical and physical properties that enable the paper to have the deformation required to form the accordion portion of the U-shaped straw without tearing. In addition, such a composition prevents the paper from tearing and collapsing under humid conditions, making it also capable of being used to manufacture U-shaped straws.

[0114] The examples disclosed above correspond to specific embodiments and must be interpreted as illustrative examples rather than restrictive examples. In fact, without departing from the scope of the present disclosure, a person skilled in the art can manufacture U-shaped straws with more than one, two or three layers as disclosed in the preferred embodiments disclosed above. In addition, a person skilled in the art can use a different grammage of paper from that disclosed in the specific embodiments, as long as the grammage remains between 30 and 140 gsm. In addition, without departing from the scope of the present disclosure, a person skilled in the art can freely use another glue to enable bonding of multiple layers and forming a U-shaped straw, as long as this glue is a food-compatible grade glue.

Claims

1. A U-shaped straw, characterized in that It is made of at least one layer of paper, characterized in that the paper comprises: 10 to 50% by dry weight of first fibers having a length of 1.4 mm to 2.5 mm; 40 to 80% by dry weight of second fibers having a length of 0.3 mm to 0.8 mm; 1 to 6% by dry weight of a sizing agent; 0.5 to 1.5% by dry weight of at least one wet strength agent, and wherein no more than 1% by dry weight of starch is present in the paper; The paper has: 4 to 8% transverse elongation, 2 to 4% machine length elongation, and • A thickness of 40 μm to 200 μm; wherein the U-shaped straw comprises at least an inner layer of paper and an outer layer of paper.

2. The U-shaped straw according to claim 1, characterized in that It has a Cobb water resistance of 15 to 34 gsm.

3. The U-shaped straw according to claim 1, wherein the wet strength agent is selected from polyamine epichlorohydrin (PAE), glyoxylated resin (GPAM - glyoxylated polyacrylamide) or formaldehyde-based resin.

4. U-shaped drinking straw according to any one of the preceding claims, characterized in that It has a machine direction tensile strength of 3 to 9 kN / m.

5. U-shaped drinking straw according to any one of the preceding claims, characterized in that It has a machine direction elongation of 2.4 to 3.5%.

6. U-shaped drinking straw according to any one of the preceding claims, characterized in that It further contains starch, said starch being present in the paper in an amount of at most 1 % by dry weight.

7. The U-shaped drinking straw according to any one of the preceding claims, wherein the sizing agent is selected from alkyl ketene dimer (AKD), alkenyl succinic anhydride (ASA) or a rosin-based sizing agent.

8. U-shaped drinking straw according to any one of the preceding claims, characterised in that The sizing agent further contains sodium carbonate, which is present in the sizing agent in an amount of at most 2% by dry weight.

9. U-shaped drinking straw according to any one of the preceding claims, characterised in that The length of the first fibers is 1.6 mm to 1.8 mm.

10. U-shaped drinking straw according to any one of the preceding claims, characterised in that The length of the second fibers is 0.5 mm to 0.7 mm.

11. U-shaped drinking straw according to any one of the preceding claims, characterised in that The paper has a thickness of 65 μm to 190 μm.

12. A U-shaped drinking straw according to any one of the preceding claims, characterised in that The paper has a machine direction tear strength of 45 g to 140 g.

13. A U-shaped drinking straw according to any one of the preceding claims, characterised in that The paper has a transverse direction tear strength of 45 g to 140 g.

14. U-shaped drinking straw according to any one of the preceding claims, characterised in that The paper has a wet burst strength of 55 KPa to 200 KPa.

15. U-shaped drinking straw according to any one of the preceding claims, characterised in that The paper has a grammage of 30 gsm to 140 gsm, preferably 60 gsm to 140 gsm.

16. U-shaped drinking straw according to any one of the preceding claims, characterised in that The paper has a transverse tensile strength of 0.8 to 5 kN / m.

17. A U-shaped drinking straw according to any one of the preceding claims, characterised in that The paper has a transverse tensile strength of 0.8 to less than 1.2 KN / m.

18. A U-shaped drinking straw according to any one of the preceding claims, characterised in that The paper has a transverse tensile strength of 1.2 to 5 kN / m.

19. The U-shaped straw according to claim 1, characterized in that The outer layer has a grammage of 80 gsm, and the inner layer has a grammage of 140 gsm.

20. The U-shaped straw according to claim 1, characterized in that The outer layer has a porosity of 360 ml / min to 800 ml / min.

21. The U-shaped straw according to any one of claims 1 to 18, characterized in that The U-shaped straw is made from three layers of paper, the layers forming a laminate.

22. The U-shaped straw according to claim 21, characterized in that The U-shaped straw is made of an outer layer with a grammage of 60 gsm, an inner layer with a grammage of 60 gsm, and a middle layer with a grammage of 120 gsm, wherein the middle layer is arranged between the inner layer and the outer layer.

23. The U-shaped straw according to claim 21, characterized in that The paper forming the outer layer has a porosity of 360 ml / min to 800 ml / min.

Images